Method for reactivation of platinum group metal catalyst with aqueous alkaline and/or reducing solutions

The present invention relates to a method for reactivation of a platinum group metal catalyst. More particularly, it relates to a method for reactivation of a platinum group metal catalyst lowered in catalytic activity as the result of having been used for the catalytic reaction of hydrocarbons optionally containing an oxygen atom.
Conventional catalysts of this type which have been used in the catalytic reaction of hydrocarbons optionally containing an oxygen atom, such as in the steam-reforming of hydrocarbons, hydro-cracking of hydrocarbons, partial oxidation of hydrocarbons and steam-reforming of alkanols, include base metal (e.g. Fe, Ni, Co) catalysts and noble metal (e.g. Pt, Pd, Ru) catalysts. In comparison with the base metal catalysts (particularly nickel catalysts), the noble metal catalysts (particularly platinum group metal catalysts) possess certain advantages as, for instance, resistance to the deposition of carbonaceous materials thereon and maintenance of high catalytic activity with use in small amounts. However, due to the expensiveness of the noble metal catalysts, the practical considerations have been concentrated in the use of the base metal catalysts. In order to overcome this shortcoming, attempts have been made to reactivate noble metal catalysts lowered in the catalytic activity so as to enable their reuse. Typical conventional procedures for such reactivation include treatment with hydrogen, steam or oxygen, and in fact, such procedures are quite effective in the elimination of certain poisonous materials in addition to the carbonaceous materials deposited on the catalysts. However, the recovery of the catalytic activity provided by these procedures is frequently not satisfactory.
In general, catalytic reactions of hydrocarbons optionally containing an oxygen atom in the presence of a platinum group metal catalyst result in deposition of various materials such as carbonaceous materials and sulfurous materials on the catalyst particles. In addition, these catalytic reactions often result in a sintering of the catalyst particles causing their mutual cohesion, whereby the particle size of the catalyst enlarged and the dispersibility of the catalyst consequently lowered. Further, the physical and chemical constitutions and behaviors of the catalysts may be gradually changed during the catalytic reactions. Due to these and other factors which are still unclear, the catalytic activity of the catalyst is lowered during the course of the catalytic reaction. In order for recovery of the catalytic activity to reach a practically satisfactory level, it is necessary to substantially reduce or eliminate these adverse factors.
As the result of extensive study, it has now been found that treatment of platinum group metal catalysts lowered in catalytic activity by contact with at least one agent selected from an inorganic alkaline substance and a reducing substance in an aqueous medium provides an effective recovery of the catalytic activity. It has also been found that the combination of treatments with both an inorganic alkaline substance in an aqueous medium and a reducing substance in an aqueous medium is particularly effective for accomplishment of the reactivation. It has further been found that the reactivation effected by the treatment with the inorganic alkaline substance and/or the reducing subtance can be more assured by treating the catalyst lowered in catalytic activity with hydrogen, steam or oxygen before or after the treatment with the inorganic alkaline substance and/or the reducing substance.
It may be noted that conventional treatment with hydrogen, steam or oxygen is effective for the removal of carbonaceous materials deposited on the catalyst but not for the elimination of sulfurous materials. On the other hand, treatment with an inorganic alkaline substance or a reducing substance is highly effective for the removal of sulfurous materials though the effect of elimination of carbonaceous materials may not be as high as obtained by conventional treatment with hydrogen, steam or oxygen. Particularly notable is the fact that while the conventional treatment has almost no effect on the recovery of the lowered catalytic activity, treatment with an inorganic alkaline substance or a reducing substance has a surprisingly significant effect.
According to the present invention, the reactivation of a platinum group metal catalyst lowered in the catalytic activity is carried out by treatment of the catalyst with at least one inorganic alkaline substance or at least one reducing substance or both, in an aqueous medium.
The platinum group metal catalyst to be subjected to the treatment in the present invention may be the one which comprises a platinum group metal such as ruthenium, rhodium, palladium, osmium, iridium or platinum as the catalyst component deposited on a carrier material such as alumina, magnesia, zirconia, titania, silica, silica-alumina, silica-magnesia, alumina-magnesia or carbon and lowered in catalytic activity as the result of having been used for the catalytic reaction of hydrocarbons optionally containing an oxygen atom. In addition to the said essential catalyst component, the platinum group metal catalyst may comprise any additive which does not materially afford any unfavorable influence thereon. Examples of the additive include any material known as the so-called "co-catalyst" such as alkali metals, alkaline earth metals, iron, copper, nickel, cobalt, chromium, tungsten, manganese or molybdenum. The term "hydrocarbons optionally containing an oxygen atom" hereinabove used is intended to mean organic compounds consisting of carbon atoms and hydrogen atoms or of carbon atoms, hydrogen atoms and oxygen atoms, and their examples include aliphatic hydrocarbons, aromatic hydrocarbons, naphthenic hydrocarbons, alkanols, alkanones, etc. Examples of the catalytic reaction are steam-reforming of hydrocarbons, hydro-cracking of hydrocarbons, partial oxidation of hydrocarbons, steam-reforming of alkanols, etc.
The inorganic alkaline substance may be an inorganic alkaline compound containing at least one alkali metal or alkaline earth metal. Examples of the alkali metals and the alkaline earth metals are sodium, potassium, calcium, magnesium, barium, strontium, etc. Preferred examples of the inorganic alkaline compounds containing these alkali metals and alkaline earth metals are hydroxides, carbonates, nitrates, sulfates, etc. or mixtures thereof. The concentration of the inorganic alkaline substance in the aqueous medium may be varied depending upon the amount of the catalyst component deposited on the carrier material, the degree of lowered catalytic activity, the temperature and pressure at which the reactivation treatment is carried out and the like. In general, however, the concentration is usually from about 0.001 to 10 N, preferably from about 0.001 to 5 N.
As the reducing substance, there may be employed normally water-soluble or water-dispersible reducing substances such as hydrazine, formaldehyde, sodium borohydride, lithium aluminum hydride, sodium tartrate, potassium tartrate, sodium potassium tartrate, calcium tartrate, sodium hydrogen tartrate, sodium formate, potassium formate, calcium formate, glucose, etc. or mixtures thereof. The concentration of the reducing substance in the aqueous medium depends on the amount of the catalyst component deposited on the carrier material, the degree of lowered catalytic activity, the temperature and pressure employed in the reactivation treatment, etc. Normally it falls in the range of about 0.01% to 10% by weight.
Even when the catalyst lowered in catalytic activity is treated solely with the inorganic alkaline substance or the reducing substance, appreciable elimination of sulfurous materials deposited on the catalyst and considerable recovery of the catalytic activity can be attained by choosing appropriate conditions for the treatment. In general, however, the treatment is preferably carried out in two separate steps, i.e. by treatment with the inorganic alkaline substance and then treatment with the reducing substance, or vice versa. When desired, such as two step treatment may be repeatedly applied until a satisfactory recovery of the catalytic activity is achieved, though a single application of two step treatment is usually sufficient.
The treatment with the inoganic alkaline substance is usually effected at room temperature (i.e. about 5.degree. to 30.degree. C.) or while heating under atmospheric pressure or an elevated pressure. Howver, it can be widely varied depending on the extent of lowered catalytic activity, the composition of the catalyst, the kind of the inorganic alkaline substance employed, etc. In general, a higher temperature affords a better result, but too high a temperature should be avoided since the carrier material may be unfavorably dissolved. Thus, the temperature is usually from about 5.degree. to 250.degree. C., preferably from about 50.degree. to 200.degree. C. The pressure may be appropriately selected so as to maintain the system for treatment in a liquid state, and such pressure do not usually exceed 50 kg/cm.sup.2.
Treatment with the reducing substance may be carried out at a temperature from room temperature to the decomposition temperature of the reducing substance under atmospheric pressure or at an elevated pressure. Although the temperature is considerably affected by various factors such as the extent to which the catalytic activity is lowered, the composition of the catalyst and the kind of the reducing substance, the temperature is ordinarily between room temperature and about 250.degree. C. insofar as the reducing substance is not decomposed. The pressure may be appropriately selected so as to keep the system in a liquid state and is normally not higher than 50 kg/cm.sup.2.
When combined two step treatments with the inorganic alkaline substance and with the reducing substance are effected in this order or vice versa, these may be performed with or without intervention of water-washing and/or drying between them.
The treatment(s) with the inorganic alkaline substance and/or with the reducing substance may be effected until a satisfactory recovery of the catalytic activity is attained. Usually, treatment(s) effected so as to eliminate not less than about 40% of carbonaceous materials and not less than about 70% of sulfurous materials deposited on the catalyst will achieve the satisfactory recovery of the catalytic activity. The contact or treating time employed will vary depending upon many factors such as whether one or two step treatments are used, the degree of recovery of catalytic activity desired, etc. Usually a treating time of several minutes to several tens hours (e.g. 3 minutes to 80 hours) is generally sufficient to achieve the aforementioned satisfactory recovery of catalytic activity. However, as stated above, the deterioration of the catalytic activity is caused not only by deposition of carbonaceous and/or sulfurous materials but also by other unclear factors, and therefore the elimination of the said deposited materials may not always be sufficient for recovery of the catalytic activity. If necessary, therefore, the said treatment(s) with the inorganic alkaline substance and/or with the reducing substance may be carried out in combination with any conventional reactivation treatment. For instance, the treatment of the catalyst with hydrogen, steam or oxygen may be effected prior to, between or subsequent to the treatment(s) with the inorganic alkaline substance and/or with the reducing substance.
Examples of usable gases for the conventional reactivation treatment are hydrogen, oxygen, steam, a mixture of hydrogen and steam, a mixture of oxygen and steam, etc. These gases may be optionally diluted with any other inert gas such as nitrogen, helium or argon. Particularly preferred are (1) hydrogen, (2) a mixture of hydrogen and steam having a hydrogen content of not less than about 30 mol%, (3) a mixture of steam and a gaseous diluent having a steam content of not less than about 30 mol %, (4) a mixture of oxygen and a gaseous diluent having an oxygen content of not less than about 0.5% by volume, (5) a mixture of oxygen, steam and a gaseous diluent having an oxygen content of not less than about 0.5% by volume and a steam content of not less than about 30% by volume, etc.
The conditions for treatment with the said gases depend on the amount of the catalyst component deposited on the carrier material, the deposited amount of poisonous materials (particularly carbonaceous materials), the concentration of the active gases, the kind of other treatment procedures employed, etc. Usually a temperature of about 350.degree. to 750.degree. C. and a pressure of about 1 to 50 atm. (absolute) are adopted. The treatment may be continued until the deposited amount of poisonous materials, particularly carbonaceous materials, is appreciably decreased. When the deposited amount of carbonaceous materials is relatively large, the generation of heat occurs sometimes. In such case, the oxygen content in the treating gases may be decreased or the use of the treating gases containing no oxygen is preferred.
After the finalization of the treatment(s) as explained above, the resulting catalyst may be washed with water and/or dried. Particularly, when the final step is the treatment with the inorganic alkaline substance or the reducing agent in an aqueous medium, water washing and drying are favorable.
As stated above, the thus reactivated catalyst is satisfactorily recovered in catalytic activity. Even when the catalyst is severely poisoned and its catalytic activity is extremely lowered, the repeated application of the above treatment(s) enables the satisfactory recovery of catalytic activity nearly equal to that of a freshly prepared catalyst. Further, when the once reactivated catalyst is lowered again in the catalytic activity, the repeated application of the above treatment(s) will reactivate it. Thus, the present invention is quite advantageous in making it possible to use an expensive platinum group metal catalyst repeatedly.

Practical and presently preferred embodiments of the present invention are illustratively shown in the following Examples wherein part(s) and % are by weight unless otherwise indicated. The amount of the catalyst required for reaction indicates a minimum amount of the catalyst required for showing a catalytic activity for reaction.
EXAMPLE 1
A catalyst comprising 2.0% of ruthenium and 0.1% of chromium oxide deposited on spheroidal particles of alumina of 4 mm in diameter as a carrier material (hereinafter referred to as "Catalyst A.sub.1 ") (325 ml) was charged into a tubular reactor of 1 inch in diameter, and a gaseous mixture comprising naphtha (content of sulfur, 2 ppm; final boiling point, 168.degree. C.), steam, hydrogen, methane and carbon oxides was fed therein to effect continuously steam-reforming reaction for 1500 hours under the following conditions:
Temperature of reactor: inlet, 450.degree. C., outlet, 524.degree. C.;
Space velocity: 2000 (l/hr);
Ratio of steam/hydrocarbon: 0.9 (number of oxygen atoms per one carbon atom in the feeding gaseous mixture);
Pressure: 13 atm. (absolute)
After 1500 hours, the resultant catalyst (hereinafter referred to as "Catalyst B.sub.1 ") was treated under the conditions as shown in Table 1 for reactivation. The reactivated catalyst was reused in steam-reforming reaction under the same conditions as mentioned above. The results are shown in Table 1.
As seen from Table 1, the reactivation treatment with hydrogen is extremely effective for elimination of carbonaceous materials, but removal of sulfurous materials is insufficient and the dispersibility can be hardly recovered so that recovery of the catalytic activity is scarcely observed (Catalysts C.sub.1 -1 and C.sub.1 -2). In the case of treatment with an inorganic alkaline substance, elimination of sulfurous materials and recovery of the dispersibility as well as recovery of the catalytic activity are good.
Table 1 Reactivated Catalyst A.sub.1 B.sub.1 C.sub.1 -1 C .sub.1 -2 D.sub.1 -1 D .sub.1 -2 D.sub.1 -3 D.sub.1 -4 D.sub.1 -5 D.sub.1 -6 D.sub.1 -7 D.sub.1 -8 D.sub.1 -9 D.sub.1 -10 D.sub.1 -11 D.sub.1 -12 Condi- Reactivating -- -- H.sub.2 O.sub.2 :N.sub.2 0.375N 0.375N 0.375N 1.0N 5.0N 0.375N 0.375N 0.375N 0.375N 0.375N 0.375N 0.001N tions agent*) (=21: NaOH NaOH NaOH NaOH NaOH Na.sub.2 CO.sub.3 KOH Ba(OH).sub.2 Sr(OH).sub.2 NaOH NaOH NaOH of 79 by treat- volume) ment for Temper- -- -- 650 500 50 70 100 100 70 100 100 100 100 148 205 100 reacti- ature (.degree.C.) vation Pressure -- -- 6.0 6.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 5.0 20.0 1.0 (ata) Time (hrs) -- -- 12 5 6.0 3.0 1.5 0.75 0.5 3.0 3.0 3.0 3.0 1.0 0.5 10.0 Post-treat- -- -- -- -- Water washing: 100.degree. C., 2 hrs. ment Drying: 100.degree. C., 16 hrs. Elimina- Carbo- -- -- 100 100 41 46 55 54 59 54 52 50 48 56 58 40 tion per- naceous centage materials of poisonous Sulfurous -- -- 33 40 78 84 95 97 100 93 90 87 87 100 100 80 materials materials (%) Specific surface area 43 20 19 17 28 30 35 37 37 3 6 35 33 32 34 37 30 (m.sup.2 /g-Ru) Amount of catalyst 52.5 -- -- -- 85 68 63 63 61 64 64 66 68 63 60 69 required for reac- tion (ml) *In case of Catalysts C.sub.1 -1 and C.sub.1 -2, the treatment was carrie out with a space velocity of 2500 (1/hr).
EXAMPLE 2
A catalyst comprising 0.3% of ruthenium deposited on spheroidal particles of alumina of 4 mm in diameter as a carrier material (1000 ml) was charged into a tubular reactor of 1 inch in diameter, and naphtha (final boiling point, 108.degree. C.) and hydrogen were fed therein to effect continuously hydro-cracking reaction under the following conditions:
Temperature of reactor at inlet: 265.degree. C;
Pressure: 46 atm. (absolute);
Ratio of hydrogen/hydrocarbon: 1.20 (by mol)
Mass velocity: 500 kg-mol/m.sup.2. hr
The conversion of hydrogen at the initial stage was 82%, and the catalytic activity was materially decreased after about 200 hours. The resultant catalyst was heated in a 0.375 N aqueous solution of sodium hydroxide at 100.degree. C. for 3 hours, washed with water at 100.degree. C. for 2 hours and then dried at 100.degree. C. for 16 hours. The thus reactivated catalyst was reused for hydro-cracking under the same conditions as above, whereby a conversion of hydrogen of 80% was observed.
EXAMPLE 3
A catalyst comprising 2.6% of ruthenium and 0.1% of chromium oxide deposited on spheroidal particles of alumina of 4 mm in diameter as a carrier material (hereinafter referred to as "Catalyst A.sub.2 ") (325 ml) was charged into a tubular reactor of 1 inch in diameter, and a gaseous mixture comprising naphtha (content of sulfur, 2 ppm; final boiling point, 168.degree. C.), steam, hydrogen, methane and carbon oxides was fed therein to effect continuously steam-reforming reaction for 2400 hours under the following conditions:
Temperature of reactor: inlet, 400.degree. C., outlet, 517.degree. C;
Space velocity: 1500 (l/hr);
Ratio of steam/hydrocarbon: 0.7 (number of oxygen atoms per one carbon atom in the feeding gaseous mixture);
Pressure: 13 atm. (absolute)
After 2400 hours, the resultant catalyst (hereinafter referred to as "Catalyst B.sub.2 ") was treated under the conditions as shown in Table 2 for reactivation. The reactivated catalyst was reused in steam-reforming reaction under the same conditions as mentioned above. The results are shown in Table 2.
As seen from Table 2, the reactivation treatment with hydrogen is extremely effective for elimination of carbonaceous materials, but removal of sulfurous materials is insufficient and the dispersibility can be hardly recovered so that recovery of the catalytic activity is scarcely observed (Catalyst C.sub.2). In the case of treatment with an inorganic alkaline substance at room temperature, elimination of sulfurous materials and recovery of the dispersibility are relatively good when the treating time is long, but the recovery of the catalytic activity is insufficient (Catalysts D.sub.2 -1 and D.sub.2 -2). The treatment with an inorganic alkaline substance under heating is proved to be effective for recovery of the catalytic activity (Catalysts D.sub.2 -3to D.sub.2 -5). In the treatment with a reducing substance, elimination of sulfurous material is good, but removal of carbonaceous materials is hardly attained. There is a tendency to recovery of the catalytic activity (Catalysts D.sub.2 -6 to D.sub.2 -13).
Table 2 Reactivated Catalyst A.sub.2 B.sub.2 C.sub.2 D.sub.2 -1 D.sub.1 -2 D.sub.1 -3 D.sub.1 -4 D.sub.2 -5 D.sub.2 -6 D.sub.2 -7 D.sub.2 -8 D.sub.2 -9 D.sub.2 -10 D.sub.2 -11 D.sub.2 -12 D.sub.2 -13 Condi- Reactivating -- -- H.sub.2 0.375N 0.375N 0.375N 0.375N 0.375N 0.4% 0.3% 0.7% 2.0% 0.3% 1.0% 1.0% 1.0% tions agent* NaOH NaOH NaOH NaOH NaOH Hydra- Lithium Sodium Sodium Glucose Hydra- Formal- Sodium of zine aluminum tart- formate zine dehyde boro- treat- hydride rate hydride ment for Temper- -- -- 650 30 30 50 100 148 20 20 20 20 60 60 60 reacti- ature (.degree.C. ) vation Pressure -- -- 6.0 1.0 1.0 1.0 1.0 5.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 (ata) Time (hrs) -- -- 12.0 3.0 10.0 6.0 3.0 1.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 Post-treat- -- -- -- Water washing: 100.degree. C., 2 hrs. Water washing: Water washing: 75.degree. C., 3 hrs. ment Drying: 100.degree. C., 16 hrs. 75.degree. C., 3 hrs. Drying: 100.degree. C., 16 hrs. Drying: 100.degree. C., 16 hrs. Elimina- Carbo- -- -- 100 12 41 43 52 56 0 0 0 0 0 0 0 0 tion per- naceous centage materials of poisonous Sulfurous -- -- 31 32 72 78 90 100 68 49 46 53 49 90 67 88 (%) Specific surface area 43 71 17 21 27 28 34 35 21 23 23 23 23 23 23 23 (m.sup.2 /g-Ru) Amount of catalyst 92 -- -- -- -- 147 110 106 276 270 272 272 276 266 270 276 required for reac- tion (ml) *In case of Catalyst C.sub.2, the treatment was carried out with a space velocity of 2500 (1/hr).
EXAMPLE 4
The reactivated catalysts as obtained in Example 3 (Catalysts D.sub.2 -1 to D.sub.2 -4 and D.sub.2 -6 to D.sub.2 -12) were each subjected to further treatment for reactivation under the conditions as shown in Table 3. The thus reactivated catalysts were each reused for continuous steam-reforming under the same conditions as shown in Example 3. The results are shown in Table 3.
As seen from Table 3, the catalysts (E.sub.3 -1 to E.sub.3 -20) reactivated in two steps are much more recovered in catalytic activity than the catalysts (D.sub.2 -1 to D.sub.2 -4 and D.sub.2 -6 to D.sub.2 -12) reactivated in one step.
Table 3 Catalyst E.sub.3 -1 E.sub.3 -2 E.sub.3 -3 E.sub.3 -4 E.sub.3 -5 E.sub.3 -6 E.sub.3 -7 E.sub.3 -8 E.sub.3 -9 E.sub.3 -10 E.sub.3 -11 E.sub.3 -12 E.sub.3 -13 E.sub.3 -14 E.sub.3 -15 E.sub.3 -16 E.sub.3 -17 E.sub.3 -18 E.sub.3 -19 E.sub.3 -20 Catalyst used D.sub.2 -1 D.sub.2 -2 D.sub.2 -3 D.sub.2 -3 D.sub.2 -4 D.sub.2 -4 D.sub.2 -6 D.sub.2 -6 D.sub.2 -11 D.sub.2 -12 D.sub.2 -1 D.sub.2 -2 D.sub.2 -3 D.sub.2 -3 D.sub.2 -4 D.sub.2 -4 D.sub.2 -7 D.sub.2 -8 D.sub.2 -9 D.sub.2 -10 Condi- Reacti- 1.0% 0.4% 0.4% 0.5% 0.4% 0.3% 0.375N 0.375N 0.375N 0.375N 0.3% 0.3% 0.7% 2.0% 0.3% 0.3% 0.375N 0.1N 0.375N 0.375N tions vating Hydra- Hydra- Hydra- Formal- Hydra- Sodium NaOH NaOH NaOH NaOH Lithium Lithium Sodium Sodium Lithium Glu- NaOH NaOH NaOH NaOH of agent zine zine zine dehyde zine boro- alum- alum- tart- formate alum- cose treat- hy- inum inum rate inum ment dride hydride hydride hydride for Temper- 60 20 20 20 20 20 50 100 100 80 20 20 20 20 20 20 50 100 100 80 reacti- ature vation (.degree.C.) Pressure 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 (ata) Time 3.0 3.0 3.0 3.0 3.0 3.0 6.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 6.0 3.0 1.5 3.0 (hrs) Post- Water washing: 75.degree. C., 3 hrs. Water washing: 100.degree. C., 2 hrs. Water washing: 75.degree. C., 3 hrs. Water washing: 100.degree. C., 2 hrs. treat- Drying: 100.degree. C., 16 hrs. Drying: 100.degree. C., 16 hrs. Drying: 100.degree. C., 16 hrs. Drying: 100.degree. C., 16 hrs. ment Elimina- Carbo- 12 41 43 43 52 52 43 54 53 47 12 41 43 43 52 52 43 44 46 47 tion per- naceous centage materials of poisonous Sulfurous 89 91 93 93 97 95 91 97 95 89 66 86 89 90 95 95 89 88 93 92 materials materials (%) Specific surface area 34 36 36 36 40 40 35 39 41 39 31 36 37 37 41 40 38 37 37 37 (m.sup.2 /g-Ru) Amount of catalyst 108 110 102 106 95 98 102 95 93 95 126 106 100 100 94 95 98 100 100 100 required for reac- tion (ml)
EXAMPLE 5
The reactivated catalyst obtained in Example 3 (Catalyst D.sub.2 -3) was treated with a 0.4% aqueous solution of hydrazine at 20.degree. C. under 1 atm. (absolute) for 3 hours, washed with water at 75.degree. C. for 3 hours and dried at 100.degree. C. for 16 hours. Then, the resulting catalyst was again subjected to treatment with a 0.375 N aqueous solution of sodium hydroxide at 50.degree. C. under 1 atm. (absolute) for 6 hours and treatment with a 0.4l % aqueous solution of hydrazine at 20.degree. C. under 1 atm. (absolute) for 3 hours, followed by washing with water at 75.degree. C. for 3 hours and drying at 100.degree. C. for 16 hours. The thus reactivated catalyst was used for steam-reforming under the same conditions as stated in Example 3. The results are as follows: elimination percentage of poisonous materials: carbonaceous materials, 75%; sulfurous material, 100%. Specific surface area: 42 m.sup.2 /g-Ru. Amount of catalyst required for reaction: 93 ml.
As seen from the above results, the repeating treatments with an inorganic alkaline substance and with a reducing substance are quite effective for reactivation of the catalyst.
EXAMPLE 6
The reactivated catalyst obtained in Example 3 (Catalyst D.sub.2 -3) was treated with a 0.7% aqueous solution of sodium tartrate at 20.degree. C. under 1 atm. (absolute) for 3 hours, washed with water at 75.degree. C. for 3 hours and dried at 100.degree. C. for 16 hours. Then, the resulting catalyst was again subjected to treatment with a 0.375 N aqueous solution of sodium hydroxide at 50.degree. C. under 1 atm. (absolute) for 6 hours and treatment with a 0.7% aqueous solution of sodium tartrate at 20.degree. C. under 1 atm. (absolute) for 3 hours, followed by washing with water at 75.degree. C. for 3 hours and drying at 100.degree. C. for 16 hours. The thus reactivated catalyst was used for steam-reforming under the same conditions as stated in Example 3. The results are as follows: elimination percentage of poisonous materials: carbonaceous materials, 70%; sulfurous material, 100%. Specific surface area: 42 m.sup.2 /g-Ru. Amount of catalyst required for reaction: 93 ml.
As seen from the above results, the repeating treatments with an inorganic alkaline substance and with a reducing substance are quite effective for reactivation of the catalyst.
EXAMPLE 7
A catalyst comprising 3.8% of ruthenium deposited on spheroidal particles of alumina of 4 mm in diameter (hereinafter referred to as "Catalyst A.sub.4 ") (325 ml) was charged into a tubular reactor of 1 inch in diameter, and naphtha (content of sulfur, 2 ppm; final boiling point, 220.degree. C.) and steam were fed therein to effect continuously steam-reforming reaction from 750 hours under the following conditions:
Temperature of reactor: inlet, 510.degree. C., outlet, 518.degree. C.;
Space velocity: 2000 (l/hr);
Ratio of steam/hydrocarbon: 1.9 (number of oxygen atoms per one carbon atom in the feeding gaseous materials);
Pressure: 13 atm. (absolute)
After 750 hours, the catalyst (hereinafter referred to as "Catalyst B.sub.4 ") was treated under the same conditions as shown in Table 4 for reactivation. The reactivated catalyst was reused in steam-reforming reaction under the same conditions as mentioned above. The results are shown in Table 4.
As seen from Table 4, treatment with an inorganic alkaline substance shows recovery of the catalytic activity, and treatment with a reducing substance shows a tendency to recovery of the catalytic activity. However, when the catalyst is severely polluted, an elevated temperature is necessary for satisfactory recovery of the catalytic activity by treatment with an inorganic alkaline substance.
Table 4 Reactivated Catalyst A.sub.4 B.sub.4 C.sub.4 D.sub.4 -1 D.sub.4 -2 D.sub.4 -3 D.sub.4 -4 D.sub.4 -5 D.sub.4 -6 D.sub.4 -7 D.sub.4 -8 D.sub.4 -9 D.sub.4 -10 D.sub.4 -11 D.sub.4 -12 D.sub.4 -13 D.sub.4 -14 D.sub.4 -15 D.sub.4 -16 D.sub.4 -17 D.sub.4 -18 Condi- Reacti- -- -- H.sub.2 0.375N 0.375N 0.375N 0.4% 1.0% 1.0% 0.375N 0.375N 0.375N 0.1N 0.375N 0.375N 0.5% 0.3% 0.3% 0.7% 2.0% 0.3% tions vating NaOH NaOH NaOH Hy- For- Sodium Na.sub.2 CO.sub.3 Ba(OH).sub.2 Sr(OH).sub.2 Na.sub.2 CO.sub.3 Ba(OH).sub.2 Sr(OH).sub.2 For- Sodium Lithium Sodium Sodium Glu- of agent dra- malde- boro- malde- boro- alumi- tart- for- cose treat- zine hyde hy- hyde hy- num rate mate ment dride dride hydride for Temper- -- -- 650 30 50 100 20 60 60 100 100 100 100 80 100 20 20 20 20 20 20 reacti- ature vation (.degree.C.) Pressure -- -- 6.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 (ata) Time -- -- 12.0 3.0 6.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 1.0 3.0 3.0 3.0 3.0 3.0 3.0 Post- -- -- -- Water washing: 100.degree. C., -- -- -- Water washing: 100.degree. C., 2 hrs. Water washing: 75.degree. C., 3 hrs. treat- 2 hrs. Drying: 100.degree. C., 16 hrs. Drying: 100.degree. C., 16 hrs. ment Drying: 100.degree. C., 16 hrs. Elimina- Carbo- -- -- 100 10 41 56 0 0 0 54 51 50 44 49 46 0 0 0 0 0 0 tion per- naceous centage materials of poisonous Sulfurous -- -- 29 30 80 94 72 71 90 91 89 86 77 80 79 56 70 51 49 57 52 materials materials (%) Specific surface area 43 20 19 23 29 36 23 26 26 3 6 35 35 32 32 31 23 23 26 26 25 23 (m.sup.2 /g-Ru) Amount of catalyst 91 -- -- -- 145 109 270 264 270 111 114 119 123 126 129 274 278 260 264 264 270 required for reac- tion (ml)
EXAMPLE 8
The reactivated catalysts as obtained in Example 7 (Catalysts D.sub.4 -1 to D.sub.4 -3, D.sub.4 -8 and D.sub.4 -10 to D.sub.4 -18) were each subjected to further treatment for reactivation under the conditions as shown in Table 5. The thus reactivated catalysts were each reused for continuous steam-reforming under the same conditions as shown in Example 7. The results are shown in Table 5.
As seen from Table 5, the catalysts (E.sub.5 -1 to E.sub.5 -19) reactivated in two steps are much more recovered in catalytic activity than the catalysts (D.sub.4 -1 to D.sub.4 -3, D.sub.4 -8 and D.sub.4 -10 to D.sub.4 -18) reactivated in one step.
Table 5 Catalyst E.sub.5 -1 E.sub.5 -2 E.sub.5 -3 E.sub.5 -4 E.sub.5 -5 E.sub.5 -6 E.sub.5 -7 E.sub.5 -8 E.sub.5 -9 E.sub.5 -10 E.sub.5 -11 E.sub.5 -12 E.sub.5 -13 D.sub.5 -14 E.sub.5 -15 E.sub.5 -16 E.sub.5 -17 E.sub.5 -18 D.sub.5 -19 Catalyst used D.sub.4 -1 D.sub.4 -3 D.sub.4 -8 D.sub.4 -8 D.sub.4 -10 D.sub.4 -11 D.sub.4 -12 D.sub.4 -13 D.sub.4 -13 D.sub.4 -14 D.sub.4 -1 D.sub.4 -2 D.sub.4 -10 D.sub.4 -11 D.sub.4 -12 D.sub.4 -15 D.sub.4 -16 D.sub.4 -17 D.sub.4 -18 Condi- Reacti- 1.0% 0.4% 0.5% 0.5% 0.5% 1.0% 0.3% 0.375N 0.1N 0.375N 0.7% 0.3% 0.3% 2.0% 0.3% 0.1N 0.1N 0.375N 0.375N tions vating Sodium Hydra- Formal- Formal- Formal- Hydra- Sodium NaOH NaOH KOH Sodium Glu- Lithium Sodium Lithium NaOH Na.sub.2 CO.sub.3 Ba(OH).sub.2 Sr(OH).sub.2 of agent boro- zine dehyde dehyde dehyde zine boro- tart- cose alumi- for- alumi- treat- hydride hy- rate num mate num ment dride hydride hydride for Temper- 60 20 20 60 20 60 20 100 100 80 20 20 20 20 20 100 100 80 100 reacti- ature vation (.degree.C.) Pressure 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 (ata) Time 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 1.0 (hrs) Post- treat- Water washing: 75.degree. C., 3 hrs. Water washing: 100.degree. C., Water washing: 75.degree. C., 3 hrs. Water washing: 100.degree. C., 2 hrs. ment Drying: 100.degree. C., 16 hrs. 2 hrs. Drying: 100.degree. C., 16 hrs. Drying: 100.degree. C., 16 hrs. Drying: 100.degree. C., 16 hrs. Elimina- Carbo- 10 56 51 51 44 49 46 54 4 4 52 10 41 44 49 46 47 44 49 46 tion per- naceous centage materials of poisonous Sulfurous 86 96 95 97 89 96 90 86 80 85 65 91 89 91 90 90 88 91 90 materials materials (%) Specific surface area 36 41 41 41 36 41 35 4 1 36 36 32 37 40 37 36 41 40 37 35 (m.sup.2 /g-Ru) Amount of catalyst 109 93 97 93 106 97 116 95 102 106 123 102 98 102 106 96 100 102 112 required for reac- tion (ml)
EXAMPLE 9
The reactivated catalyst obtained in Example 7 (Catalyst D.sub.4 -13) was treated with a 0.1 N aqueous solution of sodium hydroxide at 100.degree. C. under 1 atm. (absolute) for 3 hours, washed with water at 100.degree. C. for 2 hours and dried at 100.degree. C. for 16 hours. Then, the resulting catalyst was again subjected to treatment with a 0.5% aqueous solution of formaldehyde at 20.degree. C. under 1 atm. (absolute) for 3 hours and treatment with a 0.1 N aqueous solution of sodium hydroxide at 100.degree. C. under 1 atm. (absolute) for 3 hours, followed by washing with water at 100.degree. C. for 2 hours and drying at 100.degree. C. for 16 hours. The thus reactivated catalyst was used for steam-reforming under the same conditions as stated in Example 7. The results are as follows: elimination percentage of poisonous materials: carbonaceous materials, 80 %, sulfurous material, 100%. Specific surface area: 42 m.sup.2 /g-Ru. Amount of catalyst required for reaction: 92 ml.
As seen from the above results, the repeating treatments with a reducing substance and with an inorganic alkaline substance are quite effective for reactivation of the catalyst.
EXAMPLE 10
The reactivated catalyst obtained in Example 7 (Catalyst D.sub.4 -17) was treated with a 0.375 N aqueous solution of barium hydroxide at 80.degree. C. under 1 atm. (absolute) for 3 hours, washed with water at 100.degree. C. for 2 hours and dried at 100.degree. C. for 16 hours. Then, the resulting catalyst was again subjected to treatment with a 2.0% aqueous solution of sodium formate at 20.degree. C. under 1 atm. (absolute) for 3 hours and treatment with a 0.375 N aqueous solution of barium hydroxide at 80.degree. C. under 1 atm. (absolute) for 3 hours, followed by washing with water at 100.degree. C. for 2 hours and drying at 100.degree. C. for 16 hours. The thus reactivated catalyst was used for steam-reforming under the same conditions as stated in Example 7. The results are as follows: elimination percentage of poisonous materials: carbonaceous materials, 76% sulfurous material, 100%. Specific surface area: 42 m.sup.2 /g-Ru. Amount of catalyst required for reaction: 92 ml.
As seen from the above results, the repeating treatments with an inorganic alkaline substance and with a reducing substance are quite effective for reactivation of the catalyst.
EXAMPLE 11
The reactivated catalysts obtained in Example 4 (Catalyst E.sub.3 -5) and in Example 4 (Catalyst E.sub.3 -7)) were each reused for steam-reforming under the same conditions as shown in Example 3. The results are shown in Table 6, from which it is understood that the reactivated catalysts show the similar behavior to the fresh catalyst (Catalyst A.sub.2) in depression of the catalytic activity and their catalytic activity, particularly that of Catalyst E.sub.3 -5, is nearly equal to the catalytic activity of the fresh catalyst.
Table 6______________________________________Catalyst A.sub.2 E.sub.3 -5 E.sub.3 -7______________________________________Amount of catalyst Start 92 95 102required for 600 hours 164 171 183reaction (ml) 1200 hours 221 232 250______________________________________
EXAMPLE 12
The reactivated catalysts obtained in Example 4 (Catalyst E.sub.3 -13) and in Example 6 were each reused for steam re-forming under the same conditions as shown in Example 3. The results are shown in Table 7, from which it is seen that the reactivated catalysts show the similar behavior to the fresh catalyst (Catalyst A.sub.2) in depression of the catalytic activity and their catalytic activity, particularly that of the reactivated catalyst obtained in Example 6 is nearly equal to the catalytic activity of the fresh catalyst.
Table 7______________________________________ Obtained inCatalyst A.sub.2 E.sub.3 -13 Example 6______________________________________Amount of catalyst Start 92 100 93required for 600 hours 164 179 166reaction (ml) 1200 hours 221 242 224______________________________________
EXAMPLE 13
The reactivated catalysts obtained in Example 8 (Catalyst E.sub.5 -8) and in Example 9 were each reused for steam-reforming under the same conditions as shown in Example 7. The results are shown in Table 8, from which it is seen that the reactivated catalysts show the similar behavior to the fresh catalyst (Catalyst A.sub.4) in depression of the catalytic activity.
Table 8______________________________________ Obtained inCatalyst A.sub.4 E.sub.5 -8 Example 9______________________________________Amount of catalyst Start 91 95 92required for 200 hours 156 167 159reaction (ml) 400 hours 222 238 226______________________________________
EXAMPLE 14
The reactivated catalysts obtained in Example 8 (Catalyst E.sub.5 -16) and in Example 10 were each reused for steam-reforming under the same conditions as shown in Example 7. The results are shown in Table 9, from which it is seen that the reactivated catalysts show the similar behavior to the fresh catalyst (Catalyst A.sub.4) in depression of the catalytic activity.
Table 9______________________________________ Obtained inCatalyst A.sub.4 E.sub.5 -16 Example 10______________________________________Amount of catalyst Start 91 96 92required for 200 hours 156 166 160reaction (ml) 400 hours 222 235 229______________________________________
EXAMPLE 15
A catalyst comprising 2.0% of ruthenium and 0.1% of chromium oxide deposited on spheroidal particles of alumina of 4 mm in diameter as a carrier material (hereinafter referred to as "Catalyst A.sub.10 ") (325 ml) was charged into a tubular reactor of 1 inch in diameter, and a gaseous mixture comprising naphtha (content of sulfur, 2 ppm; final boiling point, 168.degree. C.), steam, hydrogen, methane and carbon oxides was fed therein to effect continuously steam-reforming reaction for 1500 hours under the following conditions:
Temperature of reactor: inlet, 450.degree. C., outlet, 524.degree. C.;
Space velocity: 2000 (1/hr);
Ratio of steam/hydrocarbon: 0.9 (number of oxygen atoms per one carbon atom in the feeding gaseous mixture);
Pressure: 13 atm. (absolute)
After 1500 hours, the resultant catalyst (hereinafter referred to as "Catalyst B.sub.10 ") was treated under the conditions as shown in Table 10 for reactivation. The reactivated catalyst was reused in steam-reforming reaction under the same conditions as mentioned above. The results are shown in Table 10.
As seen from Table 10, the reactivation treatment with gaseous materials is effective for elimination of carbonaceous materials, but removal of sulfurous materials is insufficient and the dispersibility can be hardly recovered so that recovery of the catalytic activity is scarcely observed (Catalysts C.sub.10 -1 to C.sub.10 -5). In the case of treatment with an inorganic alkaline substance, elimination of sulfurous materials and recovery of the dispersibility (as well as recovery of the catalytic activity) are good.
Table 10__________________________________________________________________________ ReactivatedCatalyst A.sub.10 B.sub.10 C.sub.10 -1 C.sub.10 -2 C.sub.10 -3 C.sub.10 -4 C.sub.10 -5 D.sub.10 -1 D.sub.10 -2 D.sub.10 -3 D.sub.10 -4 D.sub.10__________________________________________________________________________ -5Condi- Reactivating -- -- H.sub.2 H.sub.2 :H.sub.2 O H.sub.2 O:N.sub.2 O.sub.2 :N.sub.2 O.sub.2 :H.sub.2 O: 0.375N 0.375N 0.375N 0.375N 0.375Ntions agent* (=1:1 (=3:1 (=21: N.sub.2 (=10: NaOH Na.sub.2 CO.sub.3 Ba(OH).sub.2 NaOH NaOHof by mol) by mol) 79 by 50:40 bytreat- vol- volume)ment ume)for Temper- -- -- 600 600 650 500 600 100 100 100 50 30reacti- ature (.degree.C.)vation Pressure -- -- 6.0 6.0 6.0 6.0 6.0 1.0 1.0 1.0 1.0 1.0 (ata) Time (hrs) -- -- 6.0 6.0 12.0 5.0 10.0 1.5 3.0 3.0 6.0 10.0Post-treat- -- -- -- -- -- -- -- Water washing: 100.degree. Water washing:ment 2 hrs. 100.degree. C., hrs. Drying: 100.degree. C., 16 Drying: 100.degree. C., 16 hrs.Elimina- Carbo- -- -- 78 80 100 100 100 55 54 50 41 40tion per- naceouscentage materialsofpoisonous Sulfurous -- -- 21 28 32 40 38 95 93 87 78 75materials materials(%)Specific surface area 43 20 19 19 19 17 18 35 36 33 28 28 (m.sup.2 /g-Ru)Amount of catalyst 52.5 -- -- -- -- -- -- 63 64 66 85 --required for reac-tion (ml)__________________________________________________________________________ Note: *In case of Catalysts C.sub.10 -1 to C.sub.10 -5, the treatment was carried out with a space velocity of 2500 (1hr).
EXAMPLE 16
The reactivated catalysts as obtained in Example 15 (Catalysts C.sub.10 -1, C.sub.10 -2 and C.sub.10 -5) were each subjected to further treatment for reactivation under the conditions as shown in Table 11. The thus reactivated catalysts were each reused for continuous steam-reforming under the same conditions as shown in Example 15. The results are shown in Table 11.
As seen from Table 11, the catalysts (E.sub.11 -1 to E.sub.11 -6) reactivated in two steps are much recovered in catalytic activity.
Table 11__________________________________________________________________________Catalyst E.sub.11 -1 E.sub.11 -2 E.sub.11 -3 E.sub.11 4 E.sub.11 5 E.sub.11 -6 E.sub.11 -7 E.sub.11 8Catalyst used C.sub.10 -1 C.sub.10 -1 C.sub.10 -1 C.sub.10 -1 C.sub.10 -2 C.sub.10 -5 C.sub.10 -1 C.sub.10 -1__________________________________________________________________________Condi- Reactivating 0.375N 0.375N 0.375N 0.375N 0.1N 0.375N 0.375N 0.375Ntions agent NaOH NaOH Na.sub.2 CO.sub.3 Ba(OH).sub.2 NaOH NaOH NaOH NaOHoftreat-mentfor Temper- 50 80 100 100 100 80 30 30reacti- ature (.degree.C.)vation Pressure 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 (ata) Time (hrs) 3.0 1.5 1.5 2.0 1.5 1.5 10.0 3.0Post-treat- Water washing: 100.degree. C., 2 hrs.ment Drying: 100.degree. C., 16 hrs.Elimina- Carbo- 81 86 85 83 83 100 80 80tion per- naceouscentage materialsofpoisonous Sulfurous 83 96 94 88 90 97 80 48materials materials (%)Specific surface area 31 38 37 35 37 38 28 23 (m.sup.2 /g-Ru)Amount of catalyst 78 58 61 63 61 58 -- --required for reac-tion (ml)__________________________________________________________________________
EXAMPLE 17
The reactivated catalysts as obtained in Example 16 (Catalysts E.sub.11 -1, E.sub.11 -7 and E.sub.11 -7 and E.sub.11 -8) were each subjected to further treatment for reactivation under the conditions as shown in Table 12. The thus reactivated catalysts were each reused for continuous steam-reforming under the same conditions as shown in Example 15. The results are shown in Table 12.
As seen from Table 12, the catalysts (F.sub.12 -1 to F.sub.12 -11) reactivated in three steps are much recovered in catalytic activity.
Table 12__________________________________________________________________________Catalyst F.sub.12 -1 F.sub.12 -2 F.sub.12 -3 F.sub.12 -4 F.sub.12 -5 F.sub.12 -6 F.sub.12 -7 F.sub.12 -8 F.sub.12 F.sub.12 -10 F.sub.12 -11Catalyst used E.sub.11 -1 E.sub.11 -1 E.sub.11 -1 E.sub.11 -1 E.sub.11 -1 E.sub.11 -7 E.sub.11 -7 E.sub.11 -7 E.sub.11 -7 E.sub.11 -7 E.sub.11__________________________________________________________________________ -8Condi- Reacti- 0.4% 0.5% 0.3% 0.3% 0.3% 0.4% 0.5% 0.3% 0.7% 2.0% 1.0%tions vating Hydra- Formal- Sodium Lithium Glu- Hydra- Formal- Sodium Sodium Sodium Hydra-of agent zine dehyde boro- aluminum cose zine dehyde boro- tart- formate zinetreat- hydride hydride hydride ratementfor Temper- 20 20 20 20 20 20 20 20 20 20 60reacti- aturevation (.degree. C.) Pressure 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 (ata) Time 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 (hrs)Post-treat- Water washing: 75.degree. C., 3 hrs.ment Drying: 100.degree. C., 16 hrs.Elimina- Carbo- 81 81 81 81 81 80 80 80 80 80 80tion per- naceouscentage materialsofpoisonous Sulfurous 96 90 95 92 92 92 87 90 91 93 94materials materials (%)Specific surface area 41 40 40 40 40 37 36 35 36 36 39 (m.sup.2 /g-Ru)Amount of catalyst 53 55 56 53 56 60 61 63 61 61 56required for reac-tion (ml)__________________________________________________________________________
EXAMPLE 18
The reactivated catalysts obtained in Example 16 (Catalyst E.sub.11 -2) and in Example 17 (Catalyst F.sub.12 -1) were each reused for steam-reforming under the same conditions as shown in Example 15. The results are shown in Table 13, from which it is seen that the reactivated catalysts show the similar behavior to the fresh catalyst (Catalyst A.sub.10) in depression of the catalytic activity and their catalytic activity, particularly that of Catalyst F.sub.12 -1 is nearly equal to the catalytic activity of the fresh catalyst.
Table 13______________________________________Catalyst A.sub.10 E.sub.11 -2 F.sub.12 -1______________________________________Amount of catalyst Start 52.5 58 53required for 300 hours 123.5 139.5 125reaction (ml) 600 hours 183 208.5 186 900 hours 252 289 257______________________________________
EXAMPLE 19
A catalyst comprising 2.6% of ruthenium and 0.1% of chromium oxide deposited on spheroidal particles of alumina of 4 mm in diameter as a carrier material (hereinafter referred to as "Catalyst A.sub.14 ") (325 ml) was charged into a tubular reactor of 1 inchin diameter, and a gaseous mixture comprising naphtha (content of sulfur, 2 ppm; final boiling point, 168.degree. C.), steam, hydrogen, methane and carbon oxides was fed therein to effect continuously steam-reforming reaction for 2400 hours under the following conditions:
Temperature of reaction: inlet, 400.degree. C., outlet 517.degree. C;
Space velocity: 1500 (1/hr);
Ratio of steam/hydrocarbon: 0.7 (number of oxygen atoms per one carbon atom in the feeding gaseous mixture);
Pressure: 13 atm. (absolute)
After 2400 hours, the resultant catalyst (hereinafter referred to as "Catalyst B.sub.14 ") was treated under the conditions as shown in Table 14 for reactivation. The reactivated catalyst was reused in steam-reforming reaction under the same conditions as mentioned above. The results are shown in Table 14.
As seen from Table 14, the reactivation treatment with gaseous materials is effective for elimination of carbonaceous materials, but removal of sulfurous materials is insufficient and the dispersibility can be hardly recovered so that recovery of the catalytic activity is scarcely observed (Catalysts C.sub.14 -1 to C.sub.14 -5). In the case of treatment with an inorganic alkaline substance, elimination of sulfurous materials and recovery of the dispersibility (as well as recovery of the catalytic activity) are good.
Table 14 Reactivated Catalyst A.sub.14 B.sub.14 C.sub.14 -1 C.sub.14 -2 C.sub.14 -3 C.sub.14 -4 C.sub.14 -5 D.sub.14 -1 D.sub.14 -2 D.sub.14 -3 D.sub.14 -4 D.sub.14 -5 D.sub.14 -6 D.sub.14 -7 D.sub.14 -8 D.sub.14 -9 Condi- Reactivating -- -- H.sub.2 H.sub.2 :H.sub.2 O H.sub.2 O:N.sub.2 O.sub.2 :N.sub.2 O.sub.2 :H.sub.2 O 0.375N 0.375N 0.375N 0.375N 0.375N 0.375N 0.1N 0.375N 0.375N tions agent* (=1:1 (=3:1 (=21: N.sub.2 (=10: NaOH NaOH NaOH NaOH Na.sub.2 CO.sub.3 Ba(OH).sub.2 NaOH Na.sub.2 CO.sub.3 Ba(OH).sub.2 of by mol) by mol) 79 by 50:40 by treat- volume) volume) ment for Temper- -- -- 600 600 650 500 600 30 30 50 100 100 100 100 80 100 reacti- ature (.degree.C.) vation Pressure -- -- 6.0 6.0 6.0 6.0 6.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 (ata) Time (hrs) -- -- 6.0 6.0 12.0 5.0 10.0 3.0 10.0 6.0 3.0 3.0 3.0 3.0 3.0 1.5 Post-treat- -- -- -- -- -- -- -- Water washing: 100.degree. C., Water washing: 100.degree. C., 2 hrs. ment 2 hrs. Drying: 100.degree. C., 16 hrs. Drying: 100.degree. C., 16 hrs. Elimina- Carbo- -- -- 75 78 100 100 100 12 41 43 52 51 47 40 44 45 tion per- naceous centage materials of poisonous Sulfurous -- -- 19 25 30 37 35 32 72 78 90 88 82 75 77 76 materials materials (%) Specific surface area 43 20 19 19 19 17 18 21 27 28 34 34 32 30 30 29 (m.sup.2 /g-Ru) Amount of catalyst 92 -- -- -- -- -- -- -- -- 147 110 112 116 120 122 127 required for reac- tion (ml) Note: *In case of Catalysts C.sub.14 -1 to C.sub.14 -5, the treatment was carried out with a space velocity of 2500.sup.14 (1/hr).
EXAMPLE 20
The reactivated catalysts as obtained in Example 19 (Catalysts D.sub.14 -7 to D.sub.14 -9) were each subjected to further treatment for reactivation under the conditions as shown in Table 15. The thus reactivated catalysts were each reused for continuous steam-reforming under the same conditions as shown in Example 19. The results are shown in Table 15.
As seen from Table 15, the catalysts (E.sub.15 -1 to E.sub.15 -5) reactivated in two steps are much recovered in catalytic activity.
Table 15__________________________________________________________________________Catalyst E.sub.15 -1 E.sub.15 -2 E.sub.15 -3 E.sub.15 -4 E.sub.15 -5Catalyst used D.sub.14 -7 D.sub.14 -7 D.sub.14 -7 D.sub.14 -8 D.sub.14 -9__________________________________________________________________________Condi- Reactivating H.sub.2 H.sub.2 :H.sub.2 O 0.sub.2 :H.sub.2 O H.sub.2 H.sub.2 :H.sub.2 Otions agent*of ( = 1:1 N.sub.2 ( = 10: ( = 1:1treat- by mol) 50:40 by by mol)ment volume)for Temper- 600 600 600 650 650reacti- ature (.degree.C.) -vation Pressure 6.0 6.0 6.0 6.0 6.0 (ata) Time (hrs) 6.0 6.0 10.0 12.0 12.0 Post-treat- -- -- -- -- -- mentElimina- Carbo- 85 87 100 100 100tion per- naceouscentage materialsofpoisonous Sulfurous 80 81 84 81 82materials materials(%)Specific surface area 31 31 30 30 30(m.sup.2 /g-Ru)Amount of catalyst 105 105 110 110 112required for reac-tion (ml)__________________________________________________________________________ Note: *In case of Catalysts E.sub.15 -1 to E.sub.15 -5, the treatment was carried out with a space velocity of 2500 (1/hr).
EXAMPLE 21
The reactivated catalysts as obtained in Example 19 (Catalysts D.sub.14 -1 to D.sub.14 -4, D.sub.14 -8 and D.sub.14 -9) were each subjected to further treatment for reactivation under the conditions as shown in Table 16. The thus reactivated catalysts were each reused for continuous steam-reforming under the same conditions as shown in Example 19. The results are shown in Table 16.
As seen from Table 16, the catalysts (E.sub.16 -1 to E.sub.16 -10) reactivated in two steps are much recovered in catalytic activity.
Table 16__________________________________________________________________________Catalyst E.sub.16 -1 E.sub.16 -2 E.sub.16 -3 E.sub.16 -4 E.sub.16 -5 E.sub.16 -6 E.sub.16 -7 E.sub.16 -8 E.sub.16 -9 E.sub.16 -10Catalyst used D.sub.14 -1 D.sub.14 -2 D.sub.14 -3 D.sub.14 -3 D.sub.14 -3 D.sub.14 -4 D.sub.14 -8 D.sub.14 -8 D.sub.14 -9 D.sub.14__________________________________________________________________________ -9Condi- Reactivating 1.0% 0.4% 0.3% 0.5% 0.3% 0.3% 0.5% 0.7% 0.4% 2.0%tions agent Hydra- Hydra- Lithium Formal- Sodium Glucose Formal- Sodium Hydra- Sodiumof zine zine alumi- dehyde boro- dehyde tart- zine formatetreat- num hydride ratement hydridefor Temper- 60 20 20 20 20 20 20 20 20 20reacti- ature (.degree.C.)vation Pressure 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 (ata) Time (hrs) 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0Post-treat- Water washing: 75.degree. C., 3 hrs.ment Drying: 100.degree. C., 16 hrs.Elimina- Carbo- 12 41 43 43 43 52 44 44 45 45tion per- naceouscentage materialsofpoisonous Sulfurous 89 91 93 93 93 97 90 88 92 90materials materials(%)Specific surface area 34 36 36 36 34 40 36 36 36 36(m.sup.2 /g-Ru)Amount of catalyst 108 110 102 106 108 95 106 106 102 102required for reac-tion (ml)__________________________________________________________________________
EXAMPLE 22
The reactivated catalysts as obtained in Example 21 (Catalysts E.sub.16 -1, E.sub.16 -3 and E.sub.16 -5 to E.sub.16 -7) were each subjected to further treatment for reactivation under the conditions as shown in Table 17. The thus reactivated catalysts were each reused for continuous steam-reforming under the same conditions as shown in Example 15. The results are shown in Table 17.
As seen from Table 17, the catalysts (F.sub.17 -1 to F.sub.17 -5) reactivated in three steps are much recovered in catalytic activity.
Table 17__________________________________________________________________________Catalyst F.sub.17 -1 F.sub.17 -2 F.sub.17 -3 F.sub.17 -4 F.sub.17 -5Catalyst used E.sub.16 -1 E.sub.16 -3 E.sub.16 -5 E.sub.16 -6 E.sub.16 -7__________________________________________________________________________Condi- Reactivating H.sub.2 H.sub.2 H.sub.2 :H.sub.2 O H.sub.2 O:N.sub.2 O.sub.2 :H.sub.2 O:N.sub.2tions agent* (=1:1 (=3:1 (=10:50:40of by mol) by mol) by volume)treat-mentfor Temper- 650 600 600 650 600reacti- ature (.degree. C.)vation Pressure 6.0 6.0 6.0 6.0 6.0 (ata) Time (hrs) 12.0 6.0 6.0 12.0 10.0 Post-treat- -- -- -- -- -- mentElimina- Carbo- 100 86 87 100 100tion per- naceouscentage materialsofpoisonous Sulfurous 96 96 96 97 94materials materials(%)Specific surface area 35 37 35 40 37(m.sup.2 /g-Ru)Amount of catalyst 100 96 102 93 98required for reac-tion (ml)__________________________________________________________________________ Note: *In case of Catalysts F.sub.17 -1 to F.sub.17 -5, the treatment was carried out with a space velocity of 2500 (1/hr).
EXAMPLE 23
The reactivated catalysts obtained in Example 20 (Catalyst E.sub.15 -1) and in Example 22 (Catalyst F.sub.17 -4) were each reused for steam-reforming under the same conditions as shown in Example 19. The results are shown in Table 18, from which it is seen that the reactivated catalysts show the similar behavior to the fresh catalyst (Catalyst A.sub.14) in depression of the catalytic activity and their catalytic activity, particularly that of Catalyst F.sub.17 -4, is nearly equal to the catalytic activity of the fresh catalyst.
Table 18______________________________________Catalyst A.sub.14 E.sub.15 -1 F.sub.17 -4______________________________________Amount of catalyst Start 92 105 93required for 600 hours 164 191 168reaction (ml) 1200 hours 221 260 227______________________________________
EXAMPLE 24
A catalyst comprising 2% of ruthenium deposited on spheroidal particles of alumina of 4 mm in diameter (hereinafter referred to as "Catalyst A.sub.18 ") (6700 ml) was charged into a tubular reactor of 5 inch in diameter, and methanol and steam were fed therein to effect continuously steam-reforming reaction for 2000 hours under the following conditions:
Temperature of reactor: inlet, 580.degree. C., outlet, 620.degree. C.;
Space velocity: 15800 (1/hr);
Ratio of steam/methanol: 1.5 (by mol);
Pressure: 6 atm. (absolute)
After 2000 hours, the catalyst (hereinafter referred to as "Catalyst B.sub.18 ") was treated under the same conditions as shown in Table 18 for reactivation. The reactivated catalyst was reused in steam-reforming reaction under the same conditions as mentioned above. The results are shown in Table 18.
As seen from Table 18, treatment with an inorganic alkaline substance or a reducing substance shows recovery of the catalytic activity.
Table 18__________________________________________________________________________ ReactivatedCatalyst A.sub.18 B.sub.18 D.sub.18 -1 D.sub.18 -2 D.sub.18 -3 D.sub.18 -4__________________________________________________________________________Condi- Reactivating -- -- 0.375N 0.375N 1.0% 0.3%tions agent NaOH NaOH Hydra- Glucoseof zinetreat-mentfor Temper- -- -- 30 100 60 20reacti- ature (.degree.C.)vation Pressure -- -- 1.0 1.0 1.0 1.0 (ata) Time (hrs) -- -- 3.0 3.0 3.0 3.0Post-treat- -- -- Water washing: Water washing:ment 100.degree. C., 2 hrs. 75.degree. C., 3 hrs. Drying: 100.degree. C., 16 hrs. Drying: 100.degree. C., 16 hrs.Elimina- Carbo- -- -- 12 53 0 0tion per- naceouscentage materialsofpoisonous Sulfurous -- -- -- -- -- --materials materials(%)Specific surface area 43 17 20 34 23 23(m.sup.2 /g-Ru)Amount of catalyst 1.3 -- -- 1.6 3.8 4.0required for reac-tion (1)__________________________________________________________________________
EXAMPLE 25
The reactivated catalysts as obtained in Example 24 (Catalysts D.sub.18 -1 to D.sub.18 -4) were each subjected to further treatment for reactivation under the conditions as shown in Table 19. The thus reactivated catalysts were each reused for continuous steam-reforming under the same conditions as shown in Example 24. The results are shown in Table 19.
As seen from Table 19, the catalysts (E.sub.19 -1 to E.sub.19 -4) reactivated in two steps are much more recovered in catalytic activity than the catalysts (D.sub.18 -1 to D.sub.18 -4) reactivated in one step.
Table 19______________________________________Catalyst E.sub.19 -1 E.sub.19 -2 E.sub.19 -3 E.sub.19 -4Catalyst used D.sub.18 -1 D.sub.18 -2 D.sub.18 -3 D.sub.18 -4______________________________________Condi- Reactivating 1.0% 0.3% 0.375N 0.375Ntions agent Hydra- Sodium NaOH NaOHof zine boro-treat- hydridementfor Temperature 60 20 100 80reacti- (.degree.C.)vation Pressure 1.0 1.0 1.0 1.0 (ata) Time (hrs) 3.0 3.0 3.0 3.0Post-treat- Water washing: Water washing:ment 75.degree. C., 3 hrs. 100.degree. C., 2 hrs. Drying: Drying: 100.degree. C., 16 hrs. 100.degree. C., 16 hrs.Elimina- Carbo- 12 52 52 50tion per- naceouscentage materialsofpoisonous Sulfurous -- -- -- --materials materials(%)Specific surface area 34 40 41 38(m.sup.2 /g-Ru)Amount of catalyst 1.5 1.4 1.3 1.4required for reac-tion (1)______________________________________
EXAMPLE 26
A catalyst comprising 2.0% of ruthenium deposited on spheroidal particles of alumina of 4 mm in diameter as a carrier material (hereinafter referred to as "Catalyst A.sub.20 ") (290 ml) was charged into a tubular reactor of 1 inch in diameter, and methane (content of sulfur, 2 ppm) and air were fed therein to effect continuously partial oxidation for 2500 hours under the following conditions:
Temperature of reactor: inlet, 310.degree. C., outlet, 700.degree. C.;
Space velocity: 17500 (1/hr);
Ratio of air/methane: 2.37 (by mol);
Pressure: 1 atm. (absolute)
After 2500 hours, the resultant catalyst (hereinafter referred to as "Catalyst B.sub.20 ") was treated under the conditions as shown in Table 20 for reactivation. The reactivated catalyst was reused in partial oxidation under the same conditions as mentioned above. The results are shown in Table 20.
As seen from Table 20, treatment with an inorganic alkaline substance or a reducing substance shows recovery of the catalytic activity.
Table 20__________________________________________________________________________ ReactivatedCatalyst A.sub.20 B.sub.20 D.sub.20 -1 D.sub.20 -2 D.sub.20 -3 D.sub.20 -4__________________________________________________________________________Condi- Reactivating -- -- 0.375N 0.375N 1.0% 2.0%tions agent NaOH NaOH Formal- Sodiumof dehyde formatetreat-mentfor Temper- -- -- 30 100 60 20reacti- ature (.degree.C.)vation Pressure -- -- 1.0 1.0 1.0 1.0 (ata) Time (hrs) -- -- 3.0 3.0 3.0 3.0Post-treat- -- -- Water washing: 100.degree. C., Water washing: 75.degree. C.,ment 2 hrs. 3 hrs. Drying: 100.degree. C., 16 hrs. Drying: 100.degree. C., 16 hrs.Elimina- Carbo- -- -- 12 52 0 0tion per- naceouscentage materialsofpoisonous Sulfurous -- -- 32 95 70 55materials materials(%)Specific surface area 43 17 21 33 21 21(m.sup.2 /g-Ru)Amount of catalyst 58 -- -- 67 170 172required for reac-tion (ml)__________________________________________________________________________
EXAMPLE 27
The reactivated catalysts as obtained in Example 26 (Catalysts D.sub.20 -1 to D.sub.20 -4) were each subjected to further treatment for reactivation under the conditions as shown in Table 21. The thus reactivated catalysts were each reused for continuous partial oxidation under the same conditions as shown in Example 26. The results are shown in Table 21.
As seen from Table 21, the catalysts (E.sub.21 -1 to E.sub.21 -4) reactivated in two steps are much more recovered in catalytic activity than the catalysts (D.sub.20 -1 to D.sub.20 -4) reactivated in one step.
Table 21__________________________________________________________________________Catalyst E.sub.21 -1 E.sub.21 -2 E.sub.21 -3 E.sub.21 -4Catalyst used D.sub.20 -1 D.sub.20 -1 D.sub.20 -3 D.sub.20 -4__________________________________________________________________________Condi- Reactivating 1.0% 0.3% 0.375N 0.375Ntions agent Hydra- Sodium NaOH NaOHof zine boro-treat- hydridementfor Temper- 60 20 80 80reacti- ature (.degree.C.)vation Pressure 1.0 1.0 1.0 1.0 (ata) Time (hrs) 3.0 3.0 3.0 3.0 Post-treat- Water washing: 75.degree. C., Water washing: 100.degree. C., ment 3 hrs. 2 hrs. Drying: 100.degree. C., 16 hrs. Drying: 100.degree. C., 16 hrs.Elimina- Carbo- 12 52 47 47tion per- naceouscentage materialsofpoisonous Sulfurous 95 97 92 93materials materials(%)Specific surface area 34 40 39 37(m.sup.2 /g-Ru)Amount of catalyst 68 62 60 62required for reac-tion (ml)__________________________________________________________________________
EXAMPLE 28
A catalyst comprising 1.0% of ruthenium and 0.1% of chromium oxide deposited on spheoidal particles of alumina of 4 mm in diameter as a carrier material (hereinafter referred to as "Catalyst A.sub.23 ") (400 ml) was charged into a tubular reactor of 1 inch in diameter, and a gaseous mixture comprising naphtha (content of sulfur, 2 ppm; final boiling point, 108.degree. C.) and hydrogen was fed therein to effect continuously hydro-cracking for 700 hours under the conditions as shown in Table 22:
Table 22______________________________________Temperature of 265.degree. C.reactor at inletPressure 46 atm. (absolute)Ratio of hydrogen/ 1.20 (by mol)hydrocarbonMass velocity 500 kg-mol/m.sup.2.hr______________________________________
After 700 hours, the resultant catalyst (hereinafter referred to as "Catalyst B.sub.23 ") was treated under the conditions as shown in Table 23 for reactivation. The reactivated catalyst was reused in hydro-cracking under the same conditions as mentioned above. The results are shown in Table 23.
As seen from Table 23, the reactivation treatment with hydrogen is extremely effective for elimination of carbonaceous materials, but removal of sulfurous materials is insufficient and the dispersibility can be hardly recovered so that recovery of the catalytic activity is scarcely observed (Catalyst C.sub.23). In the case of treatment with an inorganic alkaline substance at room temperature for a long time, elimination of sulfurous materials and recovery of the dispersibility are good, but recovery of the catalytic activity is still not good (Catalysts D.sub.23 -1 and D.sub.23 -2). When treated with an inorganic alkaline substance under heating, recovery of the catalytic activity is good (Catalysts D.sub.23 -3, D.sub.23 -4, D.sub.23 -5, D.sub.23 -14, D.sub.23 -15, D.sub.23 -16). On the other hand, sole treatment with an aqueous solution of hydrazine is effective in removal of sulfurous materials but almost ineffective in removal of carbonaceous materials. Nevertheless, a tendency to recovery of the catalytic activity is seen (Catalysts D.sub.23 -6 to D.sub.23 -13).
Table 23 Reactivated Catalyst A.sub.23 B.sub.23 C.sub.23 D.sub.23 -1 D.sub.23 -2 D .sub.23 -3 D.sub.23 -4 D.sub.23 -5 D.sub.23 -6 D.sub.23 -7 D.sub.23 -8 D.sub.23 -9 D.sub.23 -10 D.sub.23 -11 D.sub.23 -12 D.sub.23 -13 D.sub.23 -14 D.sub.23 -15 D.sub.23 -16 0 .4% 0.3% 0.7% 2.0% 0.3% 1.0% 1.0% 1.0% Condi- Reactivating -- -- H.sub.2 0.375N 0.375N O.375N 0.375N 0.375N Hydra- Lithium Sodium Sodium Glu- Hydra- Form Sodium 5.0N 0.375N 0.375N tions agent* NaOH NaOH NaOH NaOH NaOH zine alumi- tart- for- cose zine alde- borohy- NaOH Na.sub.2 CO.sub.3 Ba(OH).sub.2 treat- num hy- rate mate hyde dride ment dride for Temperature -- -- 650 30 30 50 100 148 20 20 20 20 20 60 60 60 100 100 100 reacti- (.degree.C.) vation Pressure -- -- 6.0 1.0 1.0 1.0 1.0 5.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 (ata) Time (hrs) -- -- 12.0 3.0 10.0 6.0 3.0 1.0 3.0 3.0 3.03.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 Post-treat- Water washing: 100.degree. C., 2 hrs. Water washing: 75.degree. C., 3 hrs. Water washing: 75.degree. C., 3 hrs. Water washing: 100.degree. C., ment -- -- -- 2 hrs. Drying: 100.degree. C., 16 hrs. Drying: 100.degree. C., 16 hrs. Drying: 100.degree. C., 16 hrs. Drying: 100.degree. C., 16 hrs. Elimina- Carbo- tion per- naceous -- -- 100 10 30 35 47 50 0 0 0 0 0 0 0 0 50 43 40 centage materials of poisonous Sulfurous materials materials -- -- 20 40 73 79 90 100 70 51 51 54 51 91 69 88 95 86 82 (%) Specific surface area (m.sup.2 /g-Ru) 43 25 25 27 28 31 36 36 28 29 29 29 29 29 29 29 38 36 32 Conversion of hydrogen 88 5 5 7 8 50 68 69 40 39 39 39 38 45 39 38 70 68 65 (%)
EXAMPLE 29
The reactivated catalysts as obtained in Example 28 (Catalysts D.sub.23 -1 to D.sub.23 -12) were each subjected to further treatment for reactivation under the conditions as shown in Table 24. The thus reactivated catalysts were each reused for continuous hydro-cracking under the same conditions as shown in Example 28. The results are shown in Table 24.
As seen from Table 24, the catalyst (E.sub.24 -1 to E.sub.24 -20) reactivated in two steps are much more recovered in catalytic activity than the catalysts (D.sub.23 -1 to D.sub.23 -12) reactivated in one step.
Table 24 Catalyst E.sub.24 -1 E.sub.24 -2 E.sub.24 -3 E.sub.24 -4 E.sub.24 -5 E.sub.24 -6 E.sub.24 -7 E.sub.24 -8 E.sub.24 -9 E.sub.24 -10 E.sub.24 -11 E.sub.24 -12 E.sub.24 -13 E.sub.24 -14 E.sub.24 -15 E.sub.24 -16 E.sub.24 -17 E.sub.24 -18 E.sub.24 -19 E.sub.24 -20 Catalyst used D.sub.23 -1 D.sub.23 -2 D.sub.23 -3 D.sub.23 -3 D.sub.23 -4 D.sub.23 -4 D.sub.23 -6 D.sub.23 -6 D.sub.23 -11 D.sub.23 -12 D.sub.23 -1 D.sub.23 -2 D.sub.23 -3 D.sub.23 -3 D.sub.23 -4 D.sub.23 -4 D.sub.23 -7 D.sub.23 -8 D.sub.23 -9 D.sub.23 -10 Condi- Reactivating 1.0% 0.4% 0.4% 0.5% 0.4% 0.3% 0.375N 0.375N 0.375N 0.375N 0.3% 0.3% 0.7% 2 .0% 0.3% 0.3% 0.375N 0.1N 0.375N 0.375 tions agent Hydra- Hydra- Hydra- Form- Hydra- Sodium NaOH NaOH NaOH NaOH Lithium Lithium Sodium Sodium Lithium Glu- NaOH NaOH NaOH NaOH of zine zine zine alde- zine boro- alum- alum- tart- for- alum- cose treat- hyde hy- inum inum rate mate inum ment dride hydride hydride hydride for Temperature 60 20 20 20 20 20 50 100 100 100 20 20 20 20 20 20 50 100 100 80 reacti- (.degree.C.) vation Pressure 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 (ata) Time (hrs) 3.0 3.0 3.0 3.0 3.0 3.0 6.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 6.0 3.0 1.5 3.0 Post-treat- Water washing: 75.degree. C., 3 hrs. Water washing: 100.degree. C., 2 hrs. Water washing: 75.degree. C., 3 hrs. Water washing: 100.degree. C., 2 hrs. ment Drying: 100.degree. C., 16 hrs. Drying: 100.degree. C., 16 hrs. Drying: 100.degree. C., 16 hrs. Drying: 100.degree. C., 16 hrs. Elimina- Carbo- 10 30 35 35 47 47 35 49 48 39 10 30 35 35 47 47 35 36 38 39 tion per- naceous centage materials of poisonous Sulfurous 91 93 95 95 98 97 93 98 97 91 68 88 91 92 97 97 91 90 95 94 materials materials (%) Specific surface area 36 38 38 38 40 4 0 37 40 42 40 36 38 39 39 42 41 39 39 39 39 (m.sup.2 /g-Ru) Conversion of hydrogen 48 51 74 70 80 77 74 80 81 80 50 50 74 74 81 80 77 74 74 74 (%)
EXAMPLE 30
The reactivated catalyst obtained in Example 28 (Catalyst D.sub.23 -3) was treated with a 0.4% aqueous solution of hydrazine at 20.degree. C. under 1 atm. (absolute) for 3 hours, washed with water at 75.degree. C. for 3 hours and dried at 100.degree. C. for 16 hours. Then, the resulting catalyst was again subjected to treatment with a 0.375 N aqueous solution of sodium hydroxide at 50.degree. C. under 1 atm. (absolute) for 6 hours and treatment with a 0.4% aqueous solution of hydrazine at 20.degree. C. under 1 atm. (absolute) for 3 hours, followed by washing with water at 75.degree. C. for 3 hours and drying at 100.degree. C. for 16 hours. The thus reactivated catalyst was used for hydro-cracking under the same conditions as shown in Table 22. The results are shown in Table 25.
Table 25______________________________________Catalyst FElimination per- Carbon-centage of aceous 70poisonous materialsmaterials(%) Sulfurous materials 100Specific surface area 42(m.sup.2 /g-Ru)Conversion of hydrogen (%) 81______________________________________
As seen from the above results, the repeating treatments with an inorganic alkaline substance and with a reducing substance are quite effective for reactivation of the catalyst.
EXAMPLE 31
The reactivated catalysts obtained in Example 29 (Catalysts E.sub.24 -5 and E.sub.24 -7) were used for continuous hydro-cracking under the conditions as shown in Example 28. The reactivated catalysts showed a similar tendency to a freshly prepared catalyst (Catalyst A.sub.23) in depression of the catalytic activity.
EXAMPLE 32
A catalyst comprising 0.3% of ruthenium and 0.1% of chromium oxide deposited on spheroidal particles of alumina of 4 mm in diameter as a carrier material (hereinafter referred to as "Catalyst A.sub.28 ") (1000 ml) was charged into a tubular reactor of 1 inch in diameter, and naphtha (content of sulfur, 2 ppm; final boiling point, 108.degree. C.) and hydrogen were fed therein to effect continously hydro-cracking reaction under the conditions as shown in Table 27.
Table 27______________________________________Temperature of 265.degree. C.reactor at inletPressure 46 atm. (absolute)Ratio of hydrogen/ 1.20 (by mol)hydrocarbonMass velocity 500 kg-mol/m.sup.2 . hr______________________________________
After 200 hours, the resultant catalyst (hereinafter referred to as "Catalyst B.sub.28 ") was treated under the conditions as shown in Table 28 for reactivation. The reactivated catalyst was reused in hydro-cracking reaction under the same conditions as mentioned above. The results are shown in Table 28.
As seen from Table 28, the reactivation treatment with gaseous materials such as hydrogen, hydrogen-steam, oxygen-nitrogen and oxygen-nitrogen-steam is extremely effective for elimination of carbonaceous materials, but removal of sulfurous materials is not achieved and the dispersibility can be hardly recovered so that recovery of the catalytic activity is not observed (Catalysts C.sub.28 -1 to C.sub.28 -5). In the case of treatment with an inorganic alkaline substance at room temperature, elimination of sulfurous materials is accomplished, but no catalytic activity is recognized (Catalyst D.sub.28 -5). When treated with an inorganic alkaline substance under heating, elimination of sulfurous materials and recovery of the dispersibility as well as recovery of the catalytic activity are good (Catalysts D.sub.28 -1 to D.sub.28 -4).
Table 28__________________________________________________________________________ ReactivatedCatalyst A.sub.28 B.sub.28 C.sub.28 -1 C.sub.28 -2 C.sub.28 -3 C.sub.28 -4 C.sub.28 -5 D.sub.28 -1 D.sub.28 -2 D.sub.28 -3 D.sub.28 -4 D.sub.28__________________________________________________________________________ -5Condi- Reactivat- -- -- H.sub.2 H.sub.2 :H.sub.2 O H.sub.2 O:N.sub.2 O.sub.2 :N.sub.2 O.sub.2 :H.sub.2 O: 0.375N 0.375N o.375N 0.375N 0.375Ntions ing agent*) (1:1 (3:1 (21:79 N.sub.2 (10:50 NaOH Na.sub.2 CO.sub.3 Ba(OH).sub.2 NaOH NaOHof by mol) by mol) by :40 bytreat- volume) volume)ment Tempera- -- -- 600 600 650 500 600 100 100 100 50 30for ture (.degree.C.)reacti- Pressure -- -- 6.0 6.0 6.0 6.0 6.0 1.0 1.0 1.0 1.0 1.0vation (ata) Time (hrs) -- -- 6.0 6.0 12.0 5.0 10.0 1.5 3.0 3.0 6.0 10.0Post-treat- -- -- -- -- -- -- -- Water washing: 100.degree. C., 2 hrs.ment Drying: 100.degree. C., 16 hrs.Elimina- Carbo-tion per- naceous -- -- 76 78 100 100 100 44 43 40 35 30centage materialsofpoisonous Sulfurousmaterials materials -- -- 28 31 34 42 40 88 86 82 79 73(%)Specific surface area(m.sup.2 /g-Ru) 43 25 25 25 25 23 24 34 36 32 31 28Conversion ofhydrogen (%) 89 5 5 5 6 5 6 68 68 65 50 8__________________________________________________________________________
EXAMPLE 33
The reactivated catalysts as obtained in Example 32 (Catalysts C.sub.28 -1, C.sub.28 -2 and C.sub.28 -5) were each subjected to further treatment for reactivation under the conditions as shown in Table 29. The thus reactivated catalysts were each reused for continuous hydro-cracking under the same conditions as shown in Table 27. The results are shown in Table 29 (Catalysts E.sub.29 -1 to E.sub.29 -8).
Likewise, the reactivated catalysts as obtained in Example 32 (Catalysts D.sub.28 -1 and D.sub.28 -2) were each subjected to further treatment for reactivation under the conditions as shown in Table 29. The thus reactivated catalysts were each reused for continuous hydro-cracking under the same conditions as shown in Table 27. The results are shown in Table 29 (Catalysts E.sub.29 -9 to E.sub.29 -12).
As seen from Table 29, the catalyst (E.sub.29 -1 to E.sub.29 -6 and E.sub.29 -9 to E.sub.29 -12) reactivated in two steps are much more recovered in catalytic activity than the catalysts reactivated in one step.
Table 29__________________________________________________________________________Catalyst E.sub.29 -1 E.sub.29 -2 E.sub.29 -3 E.sub.29 -4 E.sub.29 -5 E.sub.29 -6 E.sub.29 -7 E.sub.29 -8 E.sub.29 -9 E.sub.29 -10 E.sub.29 -11 E.sub.29 -12Catalyst used C.sub.28 -1 C.sub.28 -1 C.sub.28 -1 C.sub.28 -1 C.sub.28 -2 C.sub.28 -5 C.sub.28 -1 C.sub.28 -1 D.sub.28 -1 D.sub.28 -2 D.sub.28 -3 D.sub.28__________________________________________________________________________ -4Condi- Reactivat- 0.375N 0.375N 0.375N 0.375N 0.1N 0.375N 0.375N 0.375N H.sub.2 H.sub.2 O:N.sub.2 H.sub.2 H.sub.2 O:N.sub.2tions ing agent NaOH NaOH Na.sub.2 CO.sub.3 Ba(OH).sub.2 NaOH NaOH NaOH NaOH (3:1 (3:1of by mol) by mol)treat- Tempera- 50 80 100 100 100 80 30 30 600 650 600 650for ture (.degree.C.)reacti- Pressure 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 6.0 6.0 6.0 6.0vation (ata) Time (hrs) 6.0 1.5 3.0 3.0 1.5 1.5 10.0 3.0 6.0 12.0 6.0 12.0Post-treat- Water washing: 100.degree. C., 2 hrs. -- -- -- --ment Drying: 100.degree. C., 16 hrs.Elimina- Carbo- 79 84 83 81 81 100 78 78 86 100 85 100tion per- naceouscentage materialsofpoisonous Sulfurous 83 96 94 88 90 97 80 51 89 87 83 80materials materials(%)Specific surface area 34 41 40 38 40 41 31 30 34 36 32 31(m.sup.2 /g-Ru)Conversion of 60 78 75 74 75 78 9 7 78 78 75 65hydrogen (%)__________________________________________________________________________
EXAMPLE 34
The reactivated catalysts as obtained in Example 33 (Catalysts E.sub.29 -1, E.sub.29 -7 and E.sub.29 -8) were each subjected to further treatment for reactivation under the conditions as shown in Table 30. The thus reactivated catalysts were each reused for continuous hydro-cracking under the same conditions as shown in Table 27. The results are shown in Table 30.
As seen from Table 30, the catalysts (F.sub.30 -1 to F.sub.30 -11) reactivated in three steps are more recovered in catalytic activity than the catalysts reactivated in two steps.
Table 30__________________________________________________________________________Catalyst F.sub.30 -1 F.sub.30 -2 F.sub.30 -3 F.sub.30 -4 F.sub.30 -5 F.sub.30 -6 F.sub.30 -7 F.sub.30 -8 F.sub.30 -9 F.sub.30 -10 F.sub.30 -11Catalyst used E.sub.29 -1 E.sub.29 -1 E.sub.29 -1 E.sub.29 -1 E.sub.29 -1 E.sub.29 -7 E.sub.29 -7 E.sub.29 -7 E.sub.29 -7 E.sub.29 7 E.sub.29__________________________________________________________________________ -8Condi- Reactivat- 0.4% 0.5% 0.3% 0.3% 0.3% 0.4% 0.4% 0.3% 0.7% 2.0% 1.0%tions ing agent Hydra- Formal- Sodium Lithium Glucose Hydra- Formal- Sodium Sodium Sodium Hydra-of zine dehyde boro- aluminum zine dehyde boro- tartrate formate zinetreat- hydride hydride hydridement Tempera- 20 20 20 20 20 20 20 20 20 20 60for ture (.degree. C.)reacti- Pressure 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0vation (ata) Time (hrs) 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0Post-treat- Water washing: 75.degree. C., 3 hrs.ment Drying: 100.degree. C., 16 hrs.Elimina- Carbo- 80 81 81 81 81 80 80 80 80 80 80tion per- naceouscentage materialsofpoisonous Sulfurous 96 90 95 92 92 92 97 90 91 93 94materials materials(%)Specific surface area 41 40 40 40 40 37 36 35 36 36 39(m.sup.2 /g-Ru)Conversion of 75 74 74 75 73 45 44 42 44 44 49hydrogen (%)__________________________________________________________________________
EXAMPLE 35
A catalyst comprising 0.3% of ruthenium deposited on spheroidal particles of alumina of 4 mm in diameter (hereinafter referred to as "Catalyst A.sub.32 ") (1000 ml ) was charged into a tubular reactor of 1 inch in diameter, and naphtha (content of sulfur, 2 ppm; final boiling point, 110.degree. C.) and hydrogen were fed therein to effect continuously hydro-cracking reaction for 200 hours under the conditions as shown in Table 31.
Table 31______________________________________Temperature ofreactor at inlet 265.degree. C.Pressure 46 atm. (absolute)Ratio of hydrogen/hydrocarbon 1.20 (by mol)Mass velocity 500 kg-mol/m.sup.2 . hr______________________________________
After 200 hours, the catalyst (hereinafter referred to as "Catalyst B.sub.32 ") was treated under the same conditions as shown in Table 32 for reactivation. The reactivated catalyst was reused in hydro-cracking reaction under the same conditions as mentioned above. The results are shown in Table 32.
As seen from Table 32, treatment with a gaseous material is extremely effective in removal of carbonaceous materials but is insufficient in removal of sulfurous materials. In addition, it is almost ineffective in recovery of the dispersibility. Thus, recovery of the catalytic activity is not substantially recognized. Treatment with an inorganic alkaline substance is effective not only in removal of sulfurous materials and recovery of the dispersibility but also in recovery of the catalytic activity.
Table 32 Reactivated Catalyst A.sub.32 B.sub.32 C.sub.32 -1 C.sub.32 -2 C.sub.32 -3 C.sub.32 -4 C.sub.32 -5 D.sub.32 -1 D.sub.32 -2 D.sub.32 -3 D.sub.32 -4 D.sub.32 -5 D.sub.32 -6 D.sub.32 -7 D.sub.32 -8 D.sub.32 -9 Condi- Reactivating -- -- H.sub.2 H.sub.2 :H.sub.2 O H.sub.2 O:N.sub.2 O.sub.2 :N.sub.2 O.sub.2 :H.sub.2 O:N.sub.2 0.375N 0.375N 0.375N 0.375N 0.375N 0.375N 0.1N 0.375N 0.375N tions agent (1:1 by (3:1 by (21:79 by (10:50:40 NaOH NaOH NaOH NaOH Na.sub.2 CO.sub.3 Ba(OH).sub.2 NaOH Na.sub.2 CO.sub.3 Ba(OH).sub.2 of mol) mol) volume) by volume) treat- Temperature -- -- 600 600 650 500 600 30 30 50 100 100 100 100 80 100 ment (.degree. C.) for Pressure -- -- 6.0 6.0 6.0 6.0 6.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 reacti- (ata) vation Time (hrs) -- -- 6.0 6.0 12.0 5.0 10.0 3.0 10.0 6.0 3.0 3.0 3.0 3.0 3.0 1.5 Post-treat- -- -- -- -- -- -- -- Water washing: 100.degree. C., 2 hrs. ment Drying: 100.degree. C., 16 hrs. Elimina- Carbo- -- -- 76 78 100 100 100 10 30 35 47 43 40 29 37 38 tion per- naceous centage materials of poisonous Sulfurous -- -- 28 31 34 42 40 40 73 79 90 86 82 76 78 77 materials materials (%) Specific surface area 43 25 25 25 25 23 2 4 27 28 31 36 36 32 30 31 30 (m.sup.2 /g-Ru) Conversion of hydrogen 89 5 5 6 7 5 5 6 8 50 68 68 68 66 65 60 (%)
EXAMPLE 36
The reactivated catalysts as obtained in Example 35 (Catalysts D.sub.32 -7, D.sub.32 -8 and D.sub.32 -9) were each subjected to further treatment for reactivation under the conditions as shown in Table 33. The thus reactivated catalysts were each reused for continuous hydro-cracking under the same conditions as shown in Table 31. The results are shown in Table 33.
As seen from Table 33, the catalysts reactivated in two steps are much more recovered in catalytic activity than the catalysts reactivated in one step.
Tabl3 33__________________________________________________________________________Catlayst E.sub.33 -1 E.sub.33 -2 E.sub.33 -3 E.sub.33 -4 E.sub.33 -5Catalyst used D.sub.32 -7 D.sub.32 -7 D.sub.32 -7 D.sub.32 -8 D.sub.32 -9__________________________________________________________________________Condi- Reactivating H.sub.2 H.sub.2 :H.sub.2 O O.sub.2 :H.sub.2 O:N.sub.2 H.sub.2 H.sub.2 :H.sub.2 Otions agent (1:1 by (10:50:40 1:1 byof mol) by volume) mol)treat-mentfor Temperature 600 600 600 650 650reacti- (.degree. C.)vation Pressure 6.0 6.0 6.0 6.0 6.0 (ata) Time (hrs) 6.0 6.0 10.0 12.0 12.0 Post-treat- -- -- -- -- -- mentElimina- Carbo- 83 85 100 100 100tion per- naceouscentage materialsofpoisonous Sulfurous 80 81 84 81 82materials materials(%)Specific surface area 31 31 30 30 30(m.sup.2 /g-Ru)Conversion of hydrogen 73 73 73 72 68(%)__________________________________________________________________________
EXAMPLE 37
The reactivated catalysts as obtained in Example 35 (Catalysts D.sub.32 -1 to D.sub.32 -5 and D.sub.32 -9) were each subjected to further treatment for reactivation under the conditions as shown in Table 34. The thus reactivated catalysts were each reused for continuous hydro-cracking under the same conditions as shown in Table 31. The results are shown in Table 34.
As seen from Table 34, the catalysts reactivated in two steps are much more recovered in catalytic activity than the catalysts reactivated in one step.
Table 34__________________________________________________________________________Catalyst F.sub.34 -1 F.sub.34 -2 F.sub.34 -3 F.sub.34 -4 F.sub.34 -5 F.sub.34 -6 F.sub.34 -7 F.sub.34 -8 F.sub.34 -9 F.sub.34 -10Catalyst used D.sub.32 -1 D.sub.32 -2 D.sub.32 -3 D.sub.32 -3 D.sub.32 -3 D.sub.32 -4 D.sub.32 -8 D.sub.32 -8 D.sub.32 -9 D.sub.32__________________________________________________________________________ -9Condi- Reactivating 1.0% 0.4% 0.3% 0.5% 0.3% 0.3% 0.5% 0.7% 0.4% 2.0%tions agent Hydra- Hydra- Lithium Formal- Sodium Glucose Formal- Sodium Hydra- Sodiumof zine zine aluminum dehyde boro- dehyde tartrate zine formatetreat- hydride hydridement Temperature 60 20 20 20 20 20 20 20 20 20for (.degree. C.)reacti- Pressure 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0vation (ata) Time (hrs) 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0Post-treat- Water washing: 75.degree. C., 3 hrs.ment Drying: 100.degree. C., 16 hrs.Elimina- Carbo- 10 30 35 35 35 47 37 37 38 38tion per- naceouscentage materialsofpoisonous Sulfurous 90 91 95 95 95 98 90 89 92 90materials materials(%)Specific surface area 37 38 38 38 37 41 38 38 38 38(m.sup.2 /g-Ru)Conversion of hydrogen 70 70 71 68 70 71 70 70 71 72(%)__________________________________________________________________________
EXAMPLE 38
The reactivated catalysts as obtained in Example 37 (Catalysts F.sub.34 -1, F.sub.34 -3 and F.sub.34 -5 to F.sub.34 -7) were each subjected to further treatment for reactivation under the conditions as shown in Table 35. The thus reactivated catalysts were each reused for continuous hydro-cracking under the same conditions as shown in Table 31. The results are shown in Table 35.
As seen from Table 35, the catalysts (G.sub.35 -1 to G.sub.35 -5) reactivated in three steps are much more recovered in catalytic activity than the catalysts reactivated in two step.
Table 35__________________________________________________________________________Catalyst G.sub.35 -1 G.sub.35 -2 G.sub.35 -3 G.sub.35 -4 G.sub.35 -5Catalyst used F.sub.34 -1 F.sub.34 -3 F.sub.34 -5 F.sub.34 -6 F.sub.34 -7__________________________________________________________________________Condi- Reactivating H.sub.2 H.sub.2 H.sub.2 :H.sub.2 O H.sub.2 O:N.sub.2 O.sub.2 :H.sub.2 O:N.sub.2tions agent (1:1 by (3:1 by (10:50:40of mol) mol) by volume)treat-mentfor Temperature 650 600 600 650 600reacti- (.degree. C.)vation Pressure 6.0 6.0 6.0 6.0 6.0 (ata) Time (hrs) 12.0 6.0 6.0 12.0 10.0 Post-treat- -- -- -- -- -- mentElimina- Carbo- 100 84 85 100 100tion per- naceouscentage materialsofpoisonous Sulfurous 96 97 97 97 96materials materials(%)Specific surface area 38 39 38 41 39(m.sup.2 /g-Ru)Conversion of hydrogen 77 78 76 79 78(%)__________________________________________________________________________
EXAMPLE 39
The reactivated catalysts (Catalysts E.sub.33 -1 and G.sub.35 -4) respectively as obtained in Examples 36 and 38 were reused for continuous hydro-cracking under the conditions as shown in Table 31. The reactivated catalysts showed the same tendency as a freshly prepared catalyst (Catalyst A.sub.32) in depression of the catalytic activity.
EXAMPLE 40
A catalyst comprising 0.3% of platinum deposited on spheroidal particles of alumina of 4 mm in diameter as a carrier material (hereinafter referred to as "Catalyst A.sub.37 ") (1000 ml) was charged into a tubular reactor of 1 inch in diameter, and a gaseous mixture comprising naphtha (content of sulfur, 2 ppm; final boiling point, 105.degree. C.) and hydrogen was fed therein to effect continuous hydro-cracking reaction for 200 hours under the conditions as shown in Table 36.
Table 36______________________________________Temperature ofreactor at inlet 260.degree. C.Pressure 46 atm. (absolute)Ratio of hydrogen/hydrocarbon 1.4 (by mol)Mass velocity 500 kg-mol/m.sup.2 . hr______________________________________
After 200 hours, the resultant catalyst (hereinafter referred to as "Catalyst B.sub.37 ") was treated under the conditions as shown in Table 37 for reactivation. The reactivated catalyst was reused in hydro-cracking reaction under the same conditions as mentioned above. The results are shown in Table 37.
As seen from Table 37, the reactivation treatment with hydrogen or hydrogen-steam is extremely effective for elimination of carbonaceous materials, but removal of sulfurous materials is insufficient and the dispersibility can be hardly recovered so that recovery of the catalytic activity is scarcely observed (Catalysts C.sub.37 -1 and C.sub.37 -2). In the case of treatment with an inorganic alkaline substance at room temperature for a long time, elimination of sulfurous materials and recovery of the dispersibility are good, but recovery of the catalytic activity is not well recognized (Catalysts D.sub.37 -1 and D.sub.37 -2). When treated with an inorganic alkaline substance under heating, the catalytic activity is highly recovered.
Table 37__________________________________________________________________________ ReactivatedCatalyst A.sub.37 B.sub.37 C.sub.37 -1 C.sub.37 -2 D.sub.37 -1 D.sub.37 -2 D.sub.37 -3 D.sub.37 -4 D.sub.37 -5__________________________________________________________________________Condi- Reactivating H.sub.2 H.sub.2 :H.sub.2 O 0.375N 0.375N 0.375N 0.375N 0.375Ntions agent*) -- -- (1:1 by NaOH NaOH NaOH Na.sub.2 CO.sub.3 Ba(OH).sub.2of mol)treat Temperaturement (.degree. C.) -- -- 600 600 30 50 100 100 100for Pressurereacti- (ata) -- -- 6.0 6.0 1.0 1.0 1.0 1.0 1.0vation Time (hrs) -- -- 6.0 6.0 10.0 6.0 1.5 3.0 3.0Post-treat- -- -- -- -- Water washing: 100.degree. C., 2 hrs.ment Drying: 100.degree. C., hrs.Elimina- Carbo- -- -- 76 78 30 35 44 43 40tion per- naceouscentage materialsofpoisonous Sulfurousmaterials materials -- -- 26 31 73 79 88 86 82(%)Specific surface area(m.sup.2 /g-Ru) 42 24 24 25 27 30 34 37 32Conversion of hydrogen(%) 85 5 7 6 5 50 68 69 69__________________________________________________________________________
EXAMPLE 41
A catalyst comprising 1.0% of ruthenium deposited on spheroidal particles of alumina of 4 mm in diameter as a carrier material (hereinafter referred to as "Catalyst A.sub.39 ") (250 ml) was charged into a tubular reactor of 1 inch in diameter, and a gaseous mixture comprising methanol (content of sulfur, 1 ppm) and hydrogen was fed therein to effect continuously hydro-cracking reaction for 200 hours under the conditions as shown in Table 38.
Table 38______________________________________Temperature ofreactor at inlet 470.degree. C.Pressure 10 atm. (absolute)Ratio of hydrogen/methanol 1.1 (by mol)Mass velocity 500 kg-mol/m.sup.2 . hr______________________________________
After 200 hours, the resultant catalyst (hereinafter referred to as "Catalyst B.sub.39 ") was treated under the conditions as shown in Table 39 for reactivation. The reactivated catalyst was reused in hydro-cracking reaction under the same conditions as mentioned above. The results are shown in Table 39.
As seen from Table 39, the reactivation treatment with hydrogen or hydrogen-steam is extremely effective for elimination of carbonaceous materials, but removal of sulfurous materials is insufficient and the dispersibility can be hardly recovered so that recovery of the catalytic activity is scarcely observed (Catalysts C.sub.39 -1 and C.sub.39 -2). In the case of treatment with an inorganic alkaline substance at room temperature for a long time, elimination of sulfurous materials and recovery of the dispersibility are good, but recovery of the catalytic activity is not well recognized (Catalysts D.sub.39 -1 and D.sub.39 -2). When treated with an inorganic alkaline substance under heating, the catalytic activity is highly recovered (Catalysts D.sub.39 -3 to D.sub.39 -5). Sole treatment with an aqueous solution of a reducing substance is effective in elimination of sulfurous materials but not in elimination of carbonaceous materials. Nevertheless, a tendency to recovery of the catalytic activity is seen (Catalysts D.sub.39 -6 to D.sub.39 -8).
Table 39__________________________________________________________________________ ReactivatedCatalyst A.sub.39 B.sub.39 C.sub.39 -1 C.sub.39 -2 D.sub.39 -1 D.sub.39 -2 D.sub.39 -3 D.sub.39 -4 D.sub.39 -5 D.sub.39 -6 D.sub.39 -7 D.sub.39__________________________________________________________________________ -8Condi- Reactivating H.sub.2 H.sub.2 :H.sub.2 O 0.375N 0.375N 0.375N 0.375N 0.375N 0.4% 0.3% 1.0%tions agent -- -- (1:1 by NaOH NaOH NaOH Na.sub.2 CO.sub.3 Ba(OH).sub.2 Hydra- Glu- Form-of mol) zine cose alde-treat- hydement Temperaturefor (.degree. C.) -- -- 600 600 30 50 100 100 100 20 20 60reacti- Pressurevation (ata) -- -- 6.0 6.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 Time (hrs) -- -- 6.0 6.0 10.0 6.0 1.5 3.0 3.0 3.0 3.0 3.0Post-treat- -- -- -- -- Water washing: 100.degree. C., 2 Water washing: 75.degree. C., 3 hrs.ment Drying: 100.degree. C., 16 hrs. Drying: 100.degree. C., 16 hrs.Elimina- Carbo- -- -- 75 76 10 35 45 43 40 0 0 0tion per- naceouscentage materialsofpoisonous Sulfurous -- -- 24 25 40 80 89 85 84 70 51 69materials materials(%)Specific surface area(mg.sup.2 /g-Ru) 42 18 18 18 22 26 31 30 28 26 27 27Amount of catalystrequired (ml) 80 -- -- -- 200 148 120 122 130 152 151 150__________________________________________________________________________
EXAMPLE 42
The reactivated catalysts as obtained in Example 41 (Catalysts D.sub.39 -1 to D.sub.39 -4) were each subjected to further treatment for reactivation under the conditions as shown in Table 40. The thus reactivated catalysts were each reused for continuous hydro-cracking under the same conditions as shown in Table 38. The results are shown in Table 40.
As seen from Table 40, the catalysts (E.sub.40 -1 to E.sub.40 -5) are effectively recovered in catalytic activity.
Table 40______________________________________Catalyst E.sub.40 -1 E.sub.40 -2 E.sub.40 -3 E.sub.40 -4 E.sub.40 -5Catalyst used D.sub.39 -1 D.sub.39 -2 D.sub.39 -3 D.sub.39 -3 D.sub.39 -4______________________________________Condi- Reacti- 1.0% 0.4% 0.4% 0.5% 0.4%tions vating Hydra- Hydra- Hydra- Formal- Hydra-of agent zine zine zine dehyde zinetreat- Tempera- 60 20 20 20 20ment aturefor (.degree. C.)reacti- Pressure 1.0 1.0 1.0 1.0 1.0vation (ata) Time (hrs) 3.0 3.0 3.0 3.0 3.0Post- Water washing: 75.degree. C., 3 hrs.treat- Drying: 100.degree. C., 16 hrs.mentElimina- Carbo- 10 35 45 45 43tion per- naceouscentage materialsofpoisonous Sulfurous 90 94 96 98 96materials materials(%)Specific surface area 30 32 35 35 34(m.sup.2 /g-Ru)Amount of catalyst 122 110 95 95 98required (ml)______________________________________
EXAMPLE 43
A catalyst comprising 1.5% of ruthenium and 0.1% of chromium oxide deposited on spheroidal particles of alumina of 4 mm in diameter as a carrier material (hereinafter referred to as "Catalyst A.sub.41 ") (290 ml) was charged into a tubular reactor of 1 inch in diameter, and a gaseous mixture comprising methane and air was fed therein to effect continuously partial combustion reaction for 500 hours under the following conditions:
Temperature of reactor: inlet, 310.degree. C., outlet, 700.degree. C;
Space velocity: 17500 (1/hr);
Ratio of air/methane: 2.37 (by mol);
Pressure: 1 atm. (absolute)
After 500 hours, the resultant catalyst (hereinafter referred to as "Catalyst B.sub.41 ") was treated under the conditions as shown in Table 41 for reactivation. The reactivated catalyst was reused in partial combustion reaction under the same conditions as mentioned above. The results are shown in Table 41.
As seen from Table 41, the reactivation treatment with hydrogen is extremely effective for elimination of carbonaceous materials, but removal of sulfurous materials is insufficient and the dispersibility can be hardly recovered so that recovery of the catalytic activity is scarcely observed (Catalyst C.sub.41 -1). In the case of treatment with an inorganic alkaline substance at room temperature for a long time, elimination of sulfurous materials and recovery of the dispersibility are good, but recovery of the catalytic activity is not well recognized (Catalysts D.sub.41 -1 and D.sub.41 -2). Treatment with an inorganic alkaline substance under heating is per se effective in recovery of the catalytic activity (Catalysts D.sub.41 -3 to D.sub.41 -5 and D.sub.41 -14 to D.sub.41 -16). Treatment with an aqueous solution of a reducing substance is effective in elimination of sulfurous materials but not in elimination of carbonaceous materials and recovery of the dispersibility. Nevertheless, a tendency to recovery of the catalytic activity is seen (Catalysts D.sub.41 -6 to D.sub.41 -13).
Table 41 Reactivated Catalyst A.sub.41 B.sub.41 C.sub.41 -1 D.sub.41 -1 D.sub.41 -2 D.sub.41 -3 D.sub.41 -4 D.sub.41 -5 D.sub.41 -6 D.sub.41 -7 D.sub.41 -8 D.sub.41 -9 D.sub.41 -10 D.sub.41 -11 D.sub.41 -12 D.sub.41 -13 D.sub.41 -14 D.sub.41 -15 D.sub.41 -16 Condi- Reactivating H.sub.2 0.375N 0.375N 0.375N 0.375N 0.375N 0.4% 0.3% 0.7% 2.0% 0.3% 1.0% 1.0% 1.0% 3.0N 0.375N 0.375N tions agent -- -- NaOH NaOH NaOH NaOH NaOH Hydra- Lithium Sodium Sodium Glu- Hydra- Form- Sodium NaOH Na.sub.2 CO.sub.3 Ba(OH).sub.2 of zine aluminum tart- for- cose zine alde- borohy- treat- hydride rate mate hyde dride ment Temperature for (.degree. C.) -- -- 650 30 30 50 100 148 20 20 20 20 20 6 0 60 60 100 100 100 reacti- Pressure vation (ata) -- -- 6.0 1.0 1.0 1.0 1.0 5.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 Time (hrs) -- -- 12.0 3.0 10.0 6.0 3.0 1.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 Post-treat- -- -- -- Water washing: 100.degree. C., 2 hrs. Water washing: 75.degree. C. 3 hrs. Water washing: 75.degree. C., 3 hrs. Water washing: 100.degree. C., 2 hrs. ment Drying: 100.degree. C., 16 hrs. Drying 100.degree. C., 16 hrs Drying: 100.degree. C., 16 hrs. Drying: 100.degree. C., 16 hrs. Elimina- Carbo- -- -- 100 12 41 43 52 58 0 0 0 0 0 0 0 0 54 50 48 tion per- naceous centage materials of poisonous Sulfurous -- -- 31 32 72 78 95 100 70 51 50 55 51 92 70 90 97 94 91 materials materials (%) Specific surface area (m.sup.2 /g-Ru) 43 17 17 21 26 28 33 34 19 21 21 21 21 21 21 21 34 32 30 Amount of catalyst required (ml) 51 -- -- -- -- 150 105 100 174 170 172 172 174 166 170 174 101 107 110
EXAMPLE 44
The reactivated catalysts as obtained in Example 43 (Catalysts D.sub.41 -1 to D.sub.41 -13) were each subjected to further treatment for reactivation under the conditions as shown in Table 42. The thus reactivated catalysts were each reused for continuous partial combustion under the same conditions as shown in Example 43. The results are shown in Table 42.
As seen from Table 42, the treatment for reactivation at the second step is quite effective for recovery of the catalytic activity.
Table 42 Catalyst E.sub.42 -1 E.sub.42 -2 E.sub.42 -3 E.sub.42 -4 E.sub.42 -5 E.sub.42 -6 E.sub.42 -7 E.sub.42 -8 E.sub.42 -9 E.sub.42 -10 E.sub.42 -11 E.sub.42 -12 E.sub.42 -13 E.sub.42 -14 E.sub.42 -15 E.sub.42 -16 E.sub.42 -17 E.sub.42 -18 E.sub.42 -19 E.sub.42 -20 Catalyst used D.sub.41 -1 D.sub.41 -2 D.sub.41 -3 D.sub.41 -3 D.sub.41 -4 D.sub.41 -4 D.sub.41 -6 D.sub.41 -6 D.sub.41 -11 D.sub.41 -12 D.sub.41 -1 D.sub.41 -2 D.sub.41 -3 D.sub.41 -3 D.sub.41 -4 D.sub.41 -4 D.sub.41 -7 D.sub.41 -8 D.sub.41 -9 D.sub.41 -9 Condi- Reactivating 1.0% 0.4% 0.4% 0.5% 0.4% 0.3% 0.375N 0.375N 0.375N 0.375N 0.3% 0.3% 0.7% 2 .0% 0.3% 0.3% 0.375N 0.1N 0.375N 0.375N tions agent Hydra- Hydra- Hydra- For- Hydra- Sodium NaOH NaOH NaOH NaOH Lithium Lithium Sodium Sodium Lithium Glu- NaOH NaOH NaOH NaOH of zine zine zine mal- zine boro- alu- alu- tart- for- alu- cose treat- dehyde hy- minum minum rate mate minum ment dride hydride hydride hydride for Temperature 60 20 20 20 20 20 50 100 100 80 20 20 20 20 20 20 50 100 100 8 0 reacti- (.degree. C.) vation Pressure 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 (ata) Time (hrs) 3.0 3.0 3.0 3.0 3.0 3.0 6.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 6.0 3.0 1.5 3.0 Post-treat- Water washing: 75.degree. C., 3 hrs. Water Washing: 100.degree. C., 2 hrs. Water washing: 75.degree. C., 3 hrs. Water washing: 100.degree. C., 2 hrs. ment Drying: 100.degree. C., 16 hrs. Drying: 100.degree. C., 16 hrs. Drying: 100.degree. C., 16 hrs. Drying: 100.degree. C., 16 hrs. Elimina- Carbo- 12 41 43 43 52 52 43 54 53 47 12 4 1 43 43 52 52 43 44 46 47 tion per- naceous centage materials of poisonous Sulfurous 91 93 95 95 97 96 92 97 96 92 68 88 91 92 96 96 91 90 94 93 materials materials (%) Specific surface area 34 36 36 36 40 40 3 5 39 41 39 31 36 37 37 41 40 38 37 37 37 (m.sup.2 /g-Ru) Amount of catalyst 150 160 101 105 75 77 103 76 74 90 149 154 102 110 76 77 115 72 80 92 required (ml)
EXAMPLE 45
The reactivated catalyst as obtained in Example 43 (Catalyst D.sub.41 -3) was treated with a 0.7% aqueous solution of sodium tartrate at 20.degree. C. under 1 atom. (absolute) for 3 hours, washed with water at 75.degree. C. for 3 hours and dried at 100.degree. C. for 16 hours. Then, the resulting catalyst was again subjected to treatment with a 0.375 N aqueous solution of sodium hydroxide at 50.degree. C. under 1 atom. (absolute) for 6 hours and treatment with a 0.7% aqueous solution of sodium tartrate at 20.degree. C. under 1 atom. (absolute) for 3 hours, followed by washing with water at 75.degree. C. for 3 hours and drying at 100.degree. C. for 16 hours. The thus reactivated catalyst was used for partial combustion under the same conditions as shown in Example 43. The results are shown in Table 43, from which it is understood that the repeating treatments are quite effective in recovery of the catalytic activity.
Table 43______________________________________Catalyst F______________________________________Elimination Carbonaceouspercentage materials 75of poison-ous mate- Sulfurousrials (%) materials 100Specific surface area(m.sup.2 /g-Ru) 42Amount of catalyst required(ml) 58______________________________________
EXAMPLE 46
The reactivated catalyst as obtained in Example 44 (Catalyst E.sub.42 -5) was used for continuous partial combustion under the conditions as shown in Example 43. The reactivated catalyst showed the same tendency as a freshly prepared catalyst in depression of the catalytic activity.
EXAMPLE 47
A catalyst comprising 1.7% of ruthenium deposited on spheroidal particles of alumina of 4 mm in diameter as a carrier material (hereinafter referred to as "Catalyst A.sub.45 ") (290 ml) was charged into a tubular reactor of 1 inch in diameter, and a gaseous mixture comprising methane and air was fed therein to effect continuously partial combustion reaction for 300 hours under the conditions as shown in Table 44.
Table 44______________________________________Temperature of at inlet 310.degree. C.reactor at outlet 700.degree. C.Space velocity 17500 hr.sup.-1Ratio of air/methane 2.37 (by mol)Pressure 1 atm. (absolute)______________________________________
After 300 hours, the resultant catalyst (hereinafter referred to as "Catalyst B.sub.45 ") was treated under the conditions as shown in Table 45 for reactivation. The reactivated catalyst was reused in partial combustion reaction under the same conditions as mentioned above. The results are shown in Table 45.
As seen from Table 45, the reactivation treatment with a gaseous material such as hydrogen, hydrogen-steam, oxygen-nitrogen or oxygen-nitrogen-steam is extremely effective for elimination of carbonaceous materials, but removal of sulfurous materials is insufficient and the dispersibility can be hardly recovered so that recovery of the catalytic activity is scarcely observed (Catalysts C.sub.45 -1 to C.sub.45 -5). In the case of treatment with an inorganic alkaline substance at room temperature, elimination of sulfurous materials is good but recovery of the catalytic activity is not seen. Treatment with an inorganic alkaline substance under heating is effective in elimination of sulfurous materials and recovery of the dispersibility, and recovery of the catalytic activity is recognized.
Table 45__________________________________________________________________________ ReactivatedCatalyst A.sub.45 B.sub.45 C.sub.45 -1 C.sub.25 -2 C.sub.45 -3 C.sub.45 -4 C.sub.45 -5 D.sub.45 -1 D.sub.45 -2 D.sub.45 -3 D.sub.45 -4 D.sub.45__________________________________________________________________________ -5Condi- Reacti- -- -- H.sub.2 H.sub.2 :H.sub.2 O H.sub.2 O:N.sub.2 O.sub.2 :N.sub.2 O.sub.2 :H.sub.2 O:N.sub.2 0.375N 0.375N 0.375N 0.375N 0.375Ntions vating (1:1 by (3:1 by (21:79 by (10:50:40 NaOH Na.sub.2 CO.sub.3 Ba(OH).sub.2 NaOH NaOHof agent mol) mol) volume by volumetreat- Temperature -- -- 600 600 650 500 600 100 100 100 50 30ment (.degree.C.)for Pressure -- -- 6.0 6.0 6.0 6.0 6.0 1.0 1.0 1.0 1.0 1.0reacti- (ata)vation Time (hrs) -- -- 6.0 6.0 12.0 5.0 10.0 1.5 3.0 3.0 6.0 10.0Post-treat- -- -- -- -- -- -- -- Water washing: 100.degree. C., 2 hrs.ment Drying: 100.degree. C., 16 hrs.Elimina- Carbo- -- -- 78 80 100 100 100 55 54 50 41 40tion per- naceouscentage materialsofpoisonous Sulfurous -- -- 23 30 34 42 40 97 95 89 80 77materials materials(%)Specific surface area 43 19 19 19 19 17 18 35 36 33 28 28(m.sup.2 /g-Ru)Amount of catalyst 65 -- -- -- -- -- -- 108 101 110 150 --required (ml)__________________________________________________________________________
EXAMPLE 48
The reactivated catalysts as obtained in Example 47 (Catalysts C.sub.45 -1, C.sub.45 -2 and C.sub.45 -5) were each subjected to further treatment for reactivation under the conditions as shown in Table 46. The thus reactivated catalysts (Catalysts E.sub.46 -1 to E.sub.46 -7) were each reused for continuous partial combustion under the same conditions as shown in Table 44. The results are shown in Table 46, from which it is understood that the treatment with an inorganic alkaline substance under heating at the second step is quite effective in recovery of the catalytic activity.
Table 46__________________________________________________________________________Catalyst E.sub.46 -1 E.sub.46 -2 E.sub.46 -3 E.sub.46 -4 E.sub.46 -5 E.sub.46 -6 E.sub.46 -7Catalyst used C.sub.45 -1 C.sub.45 -1 C.sub.45 -1 C.sub.45 -1 C.sub.45 -2 C.sub.45 -5 C.sub.45 -1__________________________________________________________________________Condi- Reactivating 0.375N 0.375N 0.375N 0.375N 0.1N 0.375N 0.375Ntions agent NaOH NaOH NaOH Ba(OH).sub.2 NaOH NaOH NaOHoftreat-mentfor Temperature 50 80 100 100 100 80 30reacti- (.degree.C.)vation Pressure 1.0 1.0 1.0 1.0 1.0 1.0 1.0 (ata) Time (hrs) 3.0 1.5 1.5 2.0 1.5 1.5 10.0Post-treat- Water washing: 100.degree. C., 2 hrs.ment Drying: 100.degree. C., 16 hrs.Elimina- Carbo- 81 86 85 83 83 100 80tion per- naceouscentage materialsofpoisonous Sulfurous 85 98 96 90 92 99 82materials materials(%)Specific surface area 31 38 37 37 37 38 28(m.sup. 2 /g-Ru)Amount of catalyst 142 115 101 106 117 120 --required (ml)__________________________________________________________________________
EXAMPLE 49
The reactivated catalysts as obtained in Example 48 (Catalyst E.sub.46 -1) were each subjected to further treatment for reactivation under the conditions as shown in Table 47. The thus reactivated catalysts (Catalysts F.sub.47 -1 to F.sub.47 -5) were each reused for continuous partial combustion under the same conditions as shown in Table 44. The results are shown in Table 47, from which it is understood that the treatment for reactivation in three steps results in higher recovery of the catalytic activity.
Table 47__________________________________________________________________________ Catalyst F.sub.47 -1 F.sub.47 -2 F.sub.47 -3 F.sub.47 -4 F.sub.47 -5Catalyst used E.sub.46 -1 E.sub.46 -1 E.sub.46 -1 E.sub.46 -1 E.sub.46 -1__________________________________________________________________________Condi- Reactivating 0.4% 0.5% 0.3% 0.3% 0.3%tions agent Hydra- Form- Sodium Lithum Glucoseof zine alde- boro- aluminiumtreat- hyde hydride hydridement Temperature 20 20 20 20 20for (.degree.C.)reacti- Pressure 1.0 1.0 1.0 1.0 1.0vation (ata) Time (hrs) 3.0 3.0 3.0 3.0 3.0Post-treat- Water washing: 75.degree. C., 3 hrs.ment Drying: 100.degree. C., 16 hrs.Elimina- Carbo- 82 82 82 82 82tion per- naceouscentage materialspoisonous Sulfurous 98 92 97 94 94materials materials(%)Specific surface area 40 39 39 39 39(m.sup.2 /g-Ru)Amount of catalyst 70 72 72 70 72required (ml)__________________________________________________________________________
EXAMPLE 50
A catalyst comprising 1.0% of ruthenium and 0.1% of chromium oxide deposited on spheroidal particles of alumina of 4 mm in diameter as a carrier material (hereinafter referred to as "Catalyst A.sub.49 ") (290 ml) was charged into a tubular reactor of 1 inch in diameter, and a gaseous mixture comprising methane and air was fed therein to effect continuously partial combustion reaction for 300 hours under the conditions as shown in Table 48.
Table 48______________________________________Temperature of at inlet 310.degree. C.reactor at outlet 700.degree. C.Space velocity 17500 hr.sup.-1Ratio of air/methane 2.37 (by mol)Pressure 1 atm. (absolute)______________________________________
After 300 hours, the resultant catalyst (hereinafter referred to as "Catalyst B.sub.49 ") was treated under the conditions as shown in Table 49 for reactivation. The reactivated catalyst was reused in partial combustion reaction under the same conditions as mentioned above. The results as shown in Table 49.
As seen from Table 49, the reactivation treatment with a gaseous material is extremely effective for elimination of carbonaceous materials, but removal of sulfurous materials is insufficient and the dispersibility can be hardly recovered so that recovery of the catalytic activity is scarcely observed. In the case of treatment with an inorganic alkaline substance, elimination of sulfurous materials and recovery of the dispersibility as well as recovery of the catalytic activity are good.
Table 49__________________________________________________________________________ ReactivatedCatalyst A.sub.49 B.sub.49 C.sub.49 -1 C.sub.49 -2 D.sub.49 -1 D.sub.49 -2 D.sub.49 -3__________________________________________________________________________Condi- Reactivating H.sub.2 O.sub.2 :H.sub.2 O: 0.375N 0.1N 0.375Ntions agent -- -- N.sub.2 (10: NaOH NaOH Na.sub.2 CO.sub.3of 50:40 bytreat- volume)ment Temperature -- -- 600 600 50 100 100for (.degree.C.)reacti- Pressure -- -- 6.0 6.0 1.0 1.0 1.0vation (ata) Time (hrs) -- -- 6.0 10.0 6.0 3.0 3.0 Post-treat- -- -- -- -- Water washing: 100.degree. C., 2 hrs. ment Drying: 100.degree. C., 16 hrs.Elimina-tion per- Carbo-centage naceous -- -- 75 100 43 40 51of materialspoisonous Sulfurous -- -- 21 37 78 80 93materials materials(%)Specific surface area 43 17 17 17 28 28 33(m.sup.2 /g-Ru)Amount of catalyst 83 -- -- -- 140 120 115required (ml)__________________________________________________________________________
EXAMPLE 51
The reactivated catalyst as obtained in Example 50 (Catalyst D.sub.49 -2) was subjected to further treatment for reactivation under the conditions as shown in Table 50. The thus reactivated catalyst was reused for continuous partial combustion under the same conditions as shown in Table 48. The results are shown in Table 50, from which is understood that the catalyst reactivated in two steps is more recovered in catalytic activity than the catalyst reactivated in one step.
Table 50______________________________________Catalyst E.sub.50 -1 E.sub.50 -2Catalyst used D.sub.49 -2 D.sub.49 -2______________________________________ Reactivating H.sub.2 O.sub.2 :H.sub.2 O:N.sub.2Condi- agent (10:50:40tions by volume)of Temperature 600 600treat- (.degree.C.)ment Pressure 6.0 6.0for (ata)reacti- Time (hrs) 6.0 10.0vation Post-treat- -- -- mentElimina-tion per- Carbo- 85 100centage naceousof materialspoisonous Sulfurous 85 89materials materials(%)Specific surface area 29 28(m.sup.2 /g-Ru)Amount of catalyst 115 114required (ml)______________________________________
EXAMPLE 52
The reactivated catalyst as obtained in Example 50 (Catalysts D.sub.49 -1 and D.sub.49 -3) was subjected to further treatment for reactivation under the conditions as shown in Table 51. The thus reactivated catalyst was reused for continuous partial combustion under the same conditions as shown in Table 48. The results are shown in Table 51, from which it is understood that the catalyst reactivated in two steps is more recovered in catalytic activity than the catalyst reactivated in one step.
Table 51______________________________________Catalyst F.sub.51 -1 F.sub.51 -2 F.sub.51 -3Catalyst used D.sub.49 -1 D.sub.49 -1 D.sub.49 -3______________________________________Condi- Reactivating 0.3% 0.3% 0.3%tions agent Lithium Sodium Glucoseof aluminum boro-treat- hydride hydridementfor Temperature 20 20 20reacti- (.degree. C.)vation Pressure 1.0 1.0 1.0 (ata) Time (hrs) 3.0 3.0 3.0 Post-treat- Water washing: 75.degree. C., 3 hrs. ment Drying: 100.degree. C., 16 hrs.Elimina- Carbo- 43 43 52tion per- naceouscentage materialsofpoisonous Sulfurous 96 96 97materials materials(%)Specific surface area 34 32 38(m.sup.2 /g-RuAmount of catalyst 94 97 90required (ml)______________________________________
EXAMPLE 53
The reactivated catalyst as obtained in Example 52 (Catalysts F.sub.51 -1 to F.sub.51 -3) were each subjected to further treatment for reactivation under the conditions as shown in Table 52. The thus reactivated catalyst were each reused for continuous partial combustion under the same conditions as shown in Table 48. The results are shown in Table 52, from which it is understood that the catalysts reactivated in three steps are more recovered in catalytic activity than the catalyst reactivated in two steps.
Table 52______________________________________Catalyst G.sub.52 -1 G.sub.52 -2 G.sub.52 -3Catalyst used F.sub.51 -1 F.sub.51 -2 F.sub.51 -3______________________________________Condi- Reactivating H.sub.2 H.sub.2 :H.sub.2 O H.sub.2 O:N.sub.2tions agent (1:1 by (3:1 byof mol) mol)treat-mentfor Temperature 600 600 650reacti- (.degree.C.)vation Pressure 6.0 6.0 6.0 (ata) Time (hrs) 6.0 6.0 12.0 Post-treat- -- -- -- mentElimina- Carbo- 86 87 100tion per- naceouscentage materialsofpoisonous Sulfurous 98 98 99materials materials(%)Specific surface area 35 33 38(m.sup.2 /g-Ru)Amount of catalyst 92 95 89required (ml)______________________________________
EXAMPLE 54
The reactivated catalysts as obtained in Examples 51 and 53 (Catalysts E.sub.50 -1 and G.sub.52 -3) were each reused for continuous partial combustion under the same conditions as shown in Table 48. As the result, it was recognized that the reactivated catalysts show the same tendency as a freshly prepared catalyst (Catalyst A.sub.49) in depression of the catalytic activity.
EXAMPLE 55
A catalyst comprising 1.0% of ruthenium deposited on spheroidal particles of alumina of 4 mm in diameter as a carrier material (hereinafter referred to as "Catalyst A.sub.54 ") (290 ml) was charged into a tubular reactor of 1 inch in diameter, and a gaseous mixture comprising methanol (content of sulfur, 5 ppm) and air was fed therein to effect continuously partial combustion for 300 hours under the conditions as shown in Table 53.
Table 53______________________________________Temperature of at inlet 280.degree. C.reactor at outlet 700.degree. C.Space velocity 17500 hr.sup.-1Ratio of air/methanol 2.40 (by mol)Pressure 1 atm. (absolute)______________________________________
After 300 hours, the resultant catalyst (hereinafter referred to as "Catalyst B.sub.54 ") was treated under the conditions as shown in Table 54 for reactivation. The reactivated catalyst was reused in partial combustion reaction under the same conditions as mentioned above. The results are shown in Table 54.
As seen from Table 54, the reactivation treatment with hydrogen or hydrogen-steam is extremely effective for elimination of carbonaceous materials, but removal of sulfurous materials is insufficient and the dispersibility can be hardly recovered so that recovery of the catalytic activity is scarcely observed. In the case of treatment with an inorganic alkaline substance at room temperature for a long time, elimination of sulfurous materials and recovery of the dispersibility are good, but recovery of the catalytic activity is insufficient. Treatment with an inorganic alkaline substance under heating is proved to be effective for recovery of the catalytic activity. In treatment with a reducing substance, elimination of sulfurous materials is hardly attained. However, there is a tendency to recovery of the catalytic activity.
Table 54__________________________________________________________________________ ReactivatedCatalyst A.sub.54 B.sub.54 C.sub.54 -1 C.sub.54 -2 D.sub.54 -1 D.sub.54 -2 D.sub.54 -3 D.sub.54 -4 D.sub.54 -5 D.sub.54 -6 D.sub.54 -7 D.sub.54__________________________________________________________________________ -8 Reactivating -- -- H.sub.2 H.sub.2 :H.sub.2 O 0.375N 0.375N 0.375N 0.375N 0.375N 0.4% 0.3% 1.0%Condi- agent (1:1 by NaOH NaOH NaOH Na.sub.2 CO.sub.3 Ba(OH).sub.2 Hydra- Glucose Formal-tions mol) zine dehydeof Temperature -- -- 600 600 30 50 100 100 100 20 20 60treat- (.degree.C.)mentfor Pressure -- -- 6.0 6.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0reacti- (ata)vation Time (hrs) -- -- 6.0 6.0 10.0 6.0 1.5 3.0 3.0 3.0 3.0 3.0 Post-treat- -- -- -- -- Water washing: 100.degree. C., 2 Water washing: ment Drying: 100.degree. C., 16 hrs. 75.degree. C., 3 hrs. Drying: 100.degree. C., 16 hrs.Elimina-tion per- Carbo- -- -- 100 100 41 43 44 43 40 0 0 0centage naceousof materialspoisonous Sulfurous -- -- 31 32 72 78 95 85 84 72 50 68materials materials(%)Specific surface area 43 13 13 17 20 24 29 28 26 22 23 23(m.sup.2 /g-Ru)Amount of catalyst 85 -- -- -- -- 150 115 120 127 163 161 160required (ml)__________________________________________________________________________
EXAMPLE 56
A catalyst comprising 2.0% of platinum deposited on spheroidal particles of alumina of 4 mm in diameter as a carrier material (hereinafter referred to as "Catalyst A.sub.56 ") (290 ml) was charged into a tubular reactor of 1 inch in diameter, and a gaseous mixture comprising methane and air was fed therein to effect continuously partial combustion for 300 hours under the conditions as shown in Table 55.
Table 55______________________________________Temperature of at inlet 310.degree. C.reactor at outlet 700.degree. C.Space velocity 17500 hr.sup.-1Ratio of air/methane 2.37 (by mol)Pressure 1 atm. (absolute)______________________________________
After 300 hours, the resultant catalyst (hereinafter referred to as "Catalyst B.sub.56 ") was treated under the conditions as shown in Table 56 for reactivation. The reactivated catalyst was reused in partial combustion reaction under the same conditions as mentioned above. The results are shown in Table 56.
As seen from Table 56, the reactivation treatment with hydrogen or hydrogen-steam is extremely effective for elimination of carbonaceous materials, but removal of sulfurous materials is insufficient and the dispersibility can be hardly recovered so that recovery of the catalytic activity is scarcely observed. In the case of treatment with an inorganic alkaline substance at room temperature, elimination of sulfurous materials and recovery of the dispersibility are relatively good when the treating time is long, but recovery of the catalytic activity is insufficient. Treatment with an inorganic alkaline substance under heating is proved to be effective for recovery of the catalytic activity. In treatment with a reducing substance, elimination of sulfurous material is good, but removal of carbonaceous materials is hardly attained. However, there is a tendency to recovery of the catalytic activity.
Table 56__________________________________________________________________________ ReactivatedCatalyst A.sub.56 B.sub.56 C.sub.56 -1 C.sub.56 -2 D.sub.56 -1 D.sub.56 -2 D.sub.56 -3 D.sub.56 -4 D.sub.56 -5 D.sub.56 -6 D.sub.56 -7 D.sub.56__________________________________________________________________________ -8Condi- Reactivating H.sub.2 H.sub.2 :H.sub.2 O 0.375N 0.375N 0.375N 0.375N 0.375N 0.4% 0.3% 1.0%tions agent -- -- (1:1 by NaOH NaOH NaOH Na.sub.2 CO.sub.3 Ba(OH).sub.2 Hydra- Glu- Form-of mol) zine cose alde-treat- hydementfor Temperaturereacti- (.degree.C.) -- -- 600 600 30 50 100 100 100 20 20 60vation Pressure (ata) -- -- 6.0 6.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 Time (hrs) -- -- 6.0 6.0 10.0 6.0 1.5 3.0 3.0 3.0 3.0 3.0 Post-treat- Water ment -- -- -- -- Water washing: 100.degree. C., 2 washing: 75.degree. C., 3 hrs. Drying: 100.degree. C., 16 hrs. Drying: 100.degree. C., 16 hrs.Elimina- Carbo-tion per- naceous -- -- 75 76 40 42 44 43 40 0 0 0centage materialsofpoisonous Sulfurousmaterials materials -- -- 22 27 72 79 94 86 86 74 52 70(%)Specific surface area(m.sup.2 /g-Ru) 41 15 15 15 22 24 29 28 27 23 24 24Amount of catalystrequired (ml) 48 -- -- -- -- 87 73 75 77 90 94 92__________________________________________________________________________
EXAMPLE 57
A catalyst comprising 2.0% of ruthenium deposited on spheroidal particles of alumina of 4 mm in diameter as a carrier material (hereinafter referred to as "Catalyst A.sub.58 ") (350 ml) was charged into a tubular reactor of 1 inch in diameter, and a gaseous mixture comprising naphtha (content of sulfur, 2 ppm; final boiling point, 108.degree. C.) and air was fed therein to effect continuous partial combustion for 200 hours under the conditions as shown in Table 57.
Table 57______________________________________Temperature of at inlet 350.degree. C.reactor at outlet 900.degree. C.Pressure 1 atm. (absolute)Ratio of air/naphtha 14.0 (by mol)Space velocity 17500 cm hr.sup.-1______________________________________
After 200 hours, the resultant catalyst (hereinafter referred to as "Catalyst B.sub.58 ") was treated under the conditions as shown in Table 58 for reactivation. The reactivated catalyst was reused in partial combustion reaction under the same conditions as mentioned above. The results are shown in Table 58.
As seen from Table 58, the reactivation treatment with a gaseous material is effective for elimination of carbonaceous materials, but removal of sulfurous materials is insufficient and the dispersibility can be hardly recovered so that recovery of the catalytic activity is scarcely observed. In the case of treatment with an inorganic alkaline substance at room temperature for a long time, elimination of sulfurous materials and recovery of the dispersibility are good, but recovery of the catalytic activity is not well recognized (Catalyst D.sub.58 -1). When treated with an inorganic alkaline substance under heating, the catalytic activity is highly recovered (Catalysts D.sub.58 -2to D.sub.58 -5). Treatment with an aqueous solution of hydrazine or the like is effective in elimination of sulfurous materials but not in elimination of carbonaceous materials. However, a tendency to recovery of the catalytic activity is recognized (Catalysts D.sub.58 -6 to D.sub.58 -8).
Table 58__________________________________________________________________________ ReactivatedCatalyst A.sub.58 B.sub.58 C.sub.58 -1 C.sub.58 -2 D.sub.58 -1 D.sub.58 -2 D.sub.58 -3 D.sub.58 -4 D.sub.58 -5 D.sub.58 -6 D.sub.58 -7 D.sub.58__________________________________________________________________________ -8Condi- Reactivating H.sub.2 H.sub.2 :H.sub.2 O 0.375N 0.375N 0.375N 0.375N 0.375N 0.4% 0.3% 1.0%tions agent -- -- (1:1 by NaOH NaOH NaOH Na.sub.2 CO.sub.3 Ba(OH).sub.2 Hydra- Glu- Form-of mol) zine cose alde-treat- hydementfor Temperature -- -- 600 600 30 50 100 100 100 20 20 60reacti- (.degree.C.)vation Pressure -- -- 6.0 6.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 (ata) Time (hrs) -- -- 6.0 6.0 10.0 6.0 1.5 3.0 3.0 3.0 3.0 3.0 Post-treat- Water washing: 100.degree. C., 2 Water washing:ment 75.degree. C., 3 hrs. -- -- -- -- Drying: 100.degree. C., 16 Drying: 100.degree. C., 16 hrs.Elimina- Carbo-tion per- naceous -- -- 100 100 48 51 52 53 51 0 0 0centage materialsofpoisonous Sulfurousmaterials materials -- -- 23 25 70 80 93 90 91 70 51 69(%)Specific surface area(m.sup.2 /g-Ru) 42 11 11 14 17 22 28 29 27 26 27 27Amount of catalystrequired (ml) 80 -- -- -- -- 156 118 115 120 155 156 155__________________________________________________________________________

Number	Date	Country
51/155512	Dec 1976	JPX
52/15635	Feb 1977	JPX
52/48285	Apr 1977	JPX
52/48286	Apr 1977	JPX
52/49507	Apr 1977	JPX

Number	Name	Date
1980829	Ridler	Nov 1934
3374182	Young	Mar 1968
3824193	Williams et al.	Jul 1974
3959382	Yeh et al.	May 1976
4148750	Pine	Apr 1979

Method for reactivation of platinum group metal catalyst with aqueous alkaline and/or reducing solutions

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