Patent Application
20130324782
This application claims priority to Russian Patent Application No. 2012122289, filed May 29, 2012, which is incorporated herein by reference in its entirety.
The invention pertains to the method for isomerization of paraffin hydrocarbons C4-C7 for production of high-octane gasoline components and can be used in the oil refining and petrochemical industries.
The closest approach to the present invention in terms of technical substance is the U.S. Pat. No. 6,495,733 B01 J 27/053 Superacid catalyst for hydroisomerization of n-paraffins. According to this invention, a porous zirconium oxide catalyst, in which not less than 70% of pores have a diameter of 1-4 nm, is used in isomerization of n-paraffin hydrocarbons.
The disadvantage of this isomerization method is the low process stability and incomplete recoverability of the catalyst activity after regeneration. Thus, when implementing the process of C5-C6 paraffin hydrocarbons isomerization according to U.S. Pat. No. 6,495,733 using a catalyst, in which 75% of pores with the diameter from 1 to 4 nm, at the temperature of 150° C., pressure of 3.0 MPa, feed space velocity of 3 h−1, and molar ratio hydrogen:feedstock of 2:1, the catalyst activity in isomerization of C5-C6 is reduced by 10% after 200 hours.
Paraffin hydrocarbons C4-C7 are isomerized on a porous zirconium oxide catalyst with the average pore diameter within 8 to 24 nm in a hydrogen atmosphere at the temperature of 100-250° C. and pressure of 1.0-5.0 MPa, molar ratio H2:hydrocarbons of (0.1-5):1, feed space velocity of 0.5-6.0 h−1. Products of isomerization are stabilized and/or fractioned to recover individual hydrocarbons or high-octane fractions.
Method for isomerization of light paraffin hydrocarbons is implemented as follows.
N-butane, C5-C6 cut or C7 cut are used as a feedstock.
The feedstock composition is given in Table 1.
The feedstock is mixed with hydrogen or hydrogen-bearing gas (HBG), heated to the temperature of 100-250° C., pressure of 1.0-5.0 MPa, molar ratio H2:hydrocarbons of (0.1-5):1, and feed space velocity of 0.5-6.0 hour−1, and fed to a reactor filled with a porous catalyst with the average pore diameter from 8 to 24 nm, which contains 0.1-3.0 weight % of a hydrogenating component on a carrier, consisting of sulfated and/or tungstated zirconium, aluminum, titanium, manganese, and iron oxides.
The reaction product is analyzed by gas-liquid chromatography using a capillary column with the OV-1 phase applied.
The isomerization depth is determined:
The proposed method offers the stable isomerization depth of unbranched paraffin hydrocarbons C4-C7 during the entire service cycle and after its regeneration.
Sulfated or tungstated zirconium dioxide in combination with aluminum oxide, titanium oxide, manganese oxide, and iron oxide is used as the catalyst carrier for isomerization of paraffin hydrocarbons C4-C7. The hydrogenating component is selected from platinum, palladium, nickel, gallium, or zinc metals.
The carrier for the catalyst of normal paraffins isomerization is prepared by mixing the components followed by extruding, drying, and calcination at 500-800° C. The catalyst is prepared by impregnating the carrier with a solution containing the hydrogenating component and subsequent drying and calcination at 400-550° C. in the air flow. The average diameter of pores of the resultant catalyst is determined by the BET method.
The process efficiency depends on the maintenance of a constant isomerization depth during operation and after regeneration of the catalyst.
Coke is deposited on the catalyst surface during operation. Some active sites become inaccessible for the source hydrocarbon as the surface deposits built up, which results in reduction of the isomerization depth. The catalyst activity is recovered by regeneration, which consists in high-temperature treatment of the catalyst in the nitrogen flow, containing 1-10 vol. % of oxygen.
Presence of nano-pores with the radius of 8-24 nm is a prerequisite for maintaining the constant isomerization depth in operation and after oxidative regeneration. The use of a catalyst with smaller pores (below 8 nm) results in reduction of the isomerization depth in the course of operation and it is incompletely recovered after oxidative regeneration. The use of a catalyst with larger pores (over 24 nm) results in reduction of the isomerization depth.
N-butane is used as the feedstock. The process is implemented on a pilot plant at the temperature of 180° C., pressure of 1.0 MPa, molar ratio H2:hydrocarbon of 0.1:1 and feed space velocity of 1.0 h−1 on a catalyst with the average pore diameter of 8 nm, which has the following composition, weight %:
1.0% Ga is used as the hydrogenating component.
Composition of the n-butane isomerization feedstock is given in Table 1.
Depth of n-butane isomerization into isobutane after 10, 200 hours and after regeneration of the catalyst is given in Table 2.
The catalyst is coked after 200 hours of continuous operation. To do this, the molar ratio hydrogen:hydrocarbons is set to 0.02:1, the temperature raised to 250° C. and held for 20 hours. After coking, the regeneration at the temperature of 500° C. in the nitrogen flow with 5 vol. % of oxygen is performed. Upon completion of regeneration, the experiment is conducted under the previous conditions.
Isomerization is performed according to the method of example 1 differing in that:
Depth of n-butane isomerization into isobutane after 10, 200 hours and after regeneration of the catalyst is given in Table 2.
Isomerization is performed according to the method of example 1 differing in that:
Depth of n-butane isomerization into isobutane after 10, 200 hours and after regeneration of the catalyst is given in Table 2.
Isomerization is performed according to the method of example 1 differing in that:
Depth of n-butane isomerization into isobutane after 10, 200 hours and after regeneration of the catalyst is given in Table 2.
Isomerization is performed according to the method of example 1 differing in that:
Depth of n-butane isomerization into isobutane after 10, 200 hours and after regeneration of the catalyst is given in Table 2.
Isomerization is performed according to the method of example 1 differing in that:
Depth of n-butane isomerization into isobutane after 10, 200 hours and after regeneration of the catalyst is given in Table 2.
Isomerization is performed according to the method of example 1 differing in that:
Depth of n-butane isomerization into isobutane after 10, 200 hours and after regeneration of the catalyst is given in Table 2.
Isomerization is performed according to the method of example 2 differing in that:
Depth of n-butane isomerization into isobutane after 10, 200 hours and after regeneration of the catalyst is given in Table 2.
Isomerization is performed according to the method of example 3 differing in that:
Depth of n-butane isomerization into isobutane after 10, 200 hours and after regeneration of the catalyst is given in Table 2.
Isomerization is performed according to the method of example 4 differing in that:
Depth of n-butane isomerization into isobutane after 10, 200 hours and after regeneration of the catalyst is given in Table 2.
Isomerization is performed according to the method of example 5 differing in that:
Depth of n-butane isomerization into isobutane after 10, 200 hours and after regeneration of the catalyst is given in Table 2.
Isomerization is performed according to the method of example 6 differing in that:
Depth of n-butane isomerization into isobutane after 10, 200 hours and after regeneration of the catalyst is given in Table 2.
C5-C6 cut is used as the feedstock. The process is implemented on a pilot plant at the temperature of 180° C., pressure of 4.0 MPa, molar ratio H2:hydrocarbon of 3.0:1, and feed space velocity of 1.0 h−1 on a catalyst with the average pore diameter of 20 nm, which has the following composition, weight %:
Pd in the amount of 0.3% is used as the hydrogenating component.
Composition of the feedstock for C5-C6 cut isomerization is given in Table 1.
Depth of isomerization for C5-C6 cut after 10, 200 hours and after regeneration of the catalyst is given in Table 2.
Isomerization is performed according to the method of example 13 differing in that:
Depth of isomerization for C5-C6 cut after 10, 200 hours and after regeneration of the catalyst is given in Table 2.
Isomerization is performed according to the method of example 13 differing in that:
Depth of isomerization for C5-C6 cut after 10, 200 hours and after regeneration of the catalyst is given in Table 2.
Isomerization is performed according to the method of example 13 differing in that:
Depth of isomerization for C5-C6 cut after 10, 200 hours and after regeneration of the catalyst is given in Table 2.
Isomerization is performed according to the method of example 13 differing in that:
Depth of isomerization for C5-C6 cut after 10, 200 hours and after regeneration of the catalyst is given in Table 2.
Isomerization is performed according to the method of example 14 differing in that:
Depth of isomerization for C5-C6 cut after 10, 200 hours and after regeneration of the catalyst is given in Table 2.
Isomerization is performed according to the method of example 15 differing in that:
Depth of isomerization for C5-C6 cut after 10, 200 hours and after regeneration of the catalyst is given in Table 2.
Isomerization is performed according to the method of example 16 differing in that:
Depth of isomerization for C5-C6 cut after 10, 200 hours and after regeneration of the catalyst is given in Table 2.
C7 cut is used as the feedstock. The process is implemented on a pilot plant at the temperature of 250° C., pressure of 4.0 MPa, molar ratio H2:hydrocarbon of 5.0:1, and feed space velocity of 0.5 h−1 on a catalyst with the average pore diameter of 8 nm, which has the following composition, weight %:
Pt in the amount of 0.5% is used as the hydrogenating component.
Composition of the feedstock for isomerization of C7 cut is given in Table 2.
Depth of isomerization for C7 cut after 10, 200 hours and after regeneration of the catalyst is given in Table 2.
Isomerization is performed according to the method of example 21 differing in that:
Depth of isomerization for C7 cut after 10, 200 hours and after regeneration of the catalyst is given in Table 2.
Isomerization is performed according to the method of example 21 differing in that:
Depth of isomerization for C7 cut after 10, 200 hours and after regeneration of the catalyst is given in Table 2.
Isomerization is performed according to the method of example 22 differing in that:
Depth of isomerization for C7 cut after 10, 200 hours and after regeneration of the catalyst is given in Table 2.
Isomerization is performed according to the method of example 21 differing in that:
Depth of isomerization for C7 cut after 10, 200 hours and after regeneration of the catalyst is given in Table 2.
Parameters of the isomerization process as per examples 1-24 (isomerization depth), average pore diameter for the catalyst, and its chemical composition are given in Table 2.
The conducted experiments indicate that it is necessary to use a zirconium oxide catalyst with the average pore diameter of 8-24 nm to ensure the efficient isomerization of C4-C7 hydrocarbons. Both deep isomerization and maintenance of the isomerization depth for the entire life cycle and after regeneration performed after the catalyst coking is ensured in this case.
When C4-C7 hydrocarbons are isomerized using a zirconium oxide catalyst with the average pore diameter below 8 nm (Examples 7, 9, 11, 17, 19, and 23), then the isomerization depth is reduced already after 200 hours and not recovered completely after regeneration.
When using a zirconium oxide catalyst with the average pore diameter over 24 nm for the isomerization process (Examples 8, 10, 12, 18, 20, and 24), both the initial and the final depth of isomerization for C4-C7 paraffin hydrocarbons is reduced by 10-20% relatively.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2012122289 | May 2012 | RU | national |
