Patent Application
20070260102
As mentioned above, the co-processing of vegetable oils mixed with mineral hydrocarbon oil in industrial hydrotreatment units is an alternative to increase the production of high aggregate value N-paraffins from raw materials derived from renewable sources, such as, short chain vegetable oils (C12-C14), being the following oils preferable material for the process described in this invention: the palm kernel oil (Elaeis guineensis), babassu oil (Orbignya speciosa), and ouricuri/licuri oil (Syagrus coronata (Martius) Beccari), among others.
Another important factor on the operational aspect is that, with the dilution of vegetable oil (V.O.), the industrial unit may operate at lower baseline temperatures, which contributes to reduce costs of the process as a whole.
The hydrotreatment process in accordance with this invention includes, hydrotreatment of a vegetable hydrocarbon oil and/or natural fats that may be used in a pure state, or in a mixture with mineral hydrocarbon oil, in the range of 0% to 100% by weight, preferably between 0% and 50% by weight, and even more preferably between 0% and 30% of vegetable hydrocarbon oil over the total weight of the hydrocarbon mixture to be processed, with the rest of said mixture constituted of mineral hydrocarbon oil, under operational conditions detailed below.
The useful mineral hydrocarbon load in the process is kerosene that is usually obtained from the refinery. Its analysis, together with the data obtained from the mixtures with vegetable oils in the various valued proportions, are found in Table 1 (at the end), which gives the parameters before the mixtured load goes through hydrotreatment.
Table 1 shows that the parameters obtained from mixtures of kerosene with vegetable oils are very close to those represented by pure kerosene load usually used in the process of obtaining N-paraffins.
The catalysts used in hydrotreatment (HDT) are basically metal oxides, that are totally or partially converted into sulfides (active phase) supported in y-alumina (y-Al2O3).
The conversion of the oxides to sulfides (sulfidation) is carried out in the hydrotreatment reactor itself. The active phase performs the reactions of hydrogenolysis and hydrogenation. The support performs the basic function of supplying a specific elevated area, in which the active components are found dispersed, in the form of small particles. Besides, the support supplies mechanical resistance and thermal stability, preventing sintering (agglomeration of the active phase). The y-alumina has a specific area between 200 and 400 m2/g, with a pore volume of 0.5 to 1.0 cm3/g and weak to moderate acidity. There is a synergistic effect between the metal sulfides of the VI-B groups, (Mo and W) and VIII (Co and Ni), in the different reactions involved in the process of hydrotreatment, so that the activity of catalysts containing sulfides, from both groups, are quite superior to the activity of individual sulfides. Therefore, mixed sulfides are normally used for the active phase (Co—Mo, Ni—Mo, Ni—W, Co—W), with an optimal ratio between metal group VIII and metal group VI-B staying within a range of 0.33 and 0.54.
Operational Conditions
In the hydrotreatment process to produce N-paraffins, the reaction takes place in the presence of hydrogen under high pressurein the operational range of 7 MPa to 15 MPa, preferably in the range of 10 to 12 MPa. The average temperature of a catalytic bed may vary from 250° C. to 400° C., preferably between 280° C. to 320° C., with a spatial velocity ranging from 0.5 h−1 to 2 h−1, preferably between 1.2 h−1 and 1.6 h−1. The catalytic bed may be divided into two or more stages with cold hydrogen injection between the stages for temperature control, with a ratio of hydrogen/mixture ranging between 200 NL of hydrogen/L of mixture to 1000 NL of hydrogen/L of mixture, preferably between 300 NL of hydrogen/L of mixture to 1000 NL of hydrogen/L of mixture.
The experimental reaction conditions for hydrotreatment are determined by typical conditions of an HDT N-paraffins unit. Tests were planned in such a way that for one same experimental condition, it was always realized also a test with a pure mineral hydrocarbon oil (M.O.) without the addition of vegetable oil (V.O.), in order to determine the efficiency caused by the presence of the vegetable oil being studied.
The process of the invention will be operational described below with reference to
In accordance with
The reactions are exothermic and in this way, the increase of temperature occurs along the catalytic bed, and thus the N-paraffin product from the output of the reactor (206) has a temperature higher than the entry (or inlet) temperature, creating the stream (109) that has a C10-C13 level varying from 70%-80%, where part of the heat is recovereded through the exchangers (204) and (203) that heats the mineral oil load (B). The stream (109) passes through another cooler (207), this time using refrigerated water, to condensing light products formed that follow by (110), which are separated from the gaseous stream in the vase (208), where a stream (111) of water produced by the process is also separated and is sent to the acid water system (C) of the refinery for treatment.
The hydrocarbon stream (112), containing the N-paraffins product coming from hydrocracking of the vegetable hydrocarbon oil and the mineral hydrocarbon oil is directed to a rectifier tower (D) (not shown), where sulfide gas and ammonia produced by the HDS and HDH reactions, respectively, are removed.
The gaseous stream (113) coming from (208), is rich in unreacted hydrogen, but also may contain high levels of sulfide gas, that may damage reactions; therefore, the level of sulfide gas is kept below a minimum baseline level through a purge (E) stream (114). The purged stream (115) passes through the reactor crucible (or vase) (209) to retain any liquid compound that has been dragged, creating the stream (116), which is compressed by the compressor (210) up to the entry (or inlet) pressure in the furnace (205), creating the stream (117). The stream (117) is mixed with the stream (118), which contains pure hydrogen to compensate the consumed hydrogen, producing a stream rich in hydrogen (119) which is then mixed with stream (106) in the entrance of the furnace (205).
The N-paraffin product at the bottom of the rectifier tower (D) passes through two fractionators (not shown in the Figure) used to separate the three streams, C10-, C10-C13 and C13+.
The proof of technical viability of the proposed process shall be described below based on the evaluation of the quality and increase of N-paraffins production.
Normal C-10-C13 Paraffin Content
The quality of the product after processing in accordance with this invention, measured at the outlet of the rectifier tower (D), is associated to the content of purity obtained in the C10-C13 N-paraffins streams which were analyzed by gas chromatography, shows concentration over 98% by weight, since the maximum content allowed for branching in these products should not be over 2%.
As expected from the concept of the invention, the liquid product that results from the processing of the mixture of vegetable hydrocarbon oil and mineral origin in accordance with the invention, would be basically made up of linear hydrocarbons, with contents of C10-C13 N-paraffins very similar to those obtained using only kerosene as the sole input, as shown by Graph 1.
In accordance with this parameter, the results obtained through the hydrotreatment processing of a mixture of vegetable and mineral loads in accordance with this invention, indicates a mass increase in the production of N-paraffins, mainly from the C10-C13 stream which shows the viability of using this type of mixture when mineral raw material in refineries is not sufficient to fulfill the demand for C10-C13 N-paraffins while continuing to use the same industrial process.
Density of the Products
Table 2 (at the end) shows that depending on the concentration of vegetable oil in the hydrotreatment load, the density and the refractory index of the product may be maintained constant or present a slightly higher values than the values presented by products produced by processing a load of pure kerosene, and that these small alterations are not significant enough to influence the results when employing the intended process of mixtures, such as those presented below.
Analysis of the Aromatics Contents
Another specification to be controlled is the product aromatic content that must be lower than 0.7% by weight.
In Table 3 (at the end) we can see that the addition of vegetable hydrocarbon oil maintains or reduces the level of aromatics in the final product, when compared to processing a load of pure kerosene, which in environmental terms contributes very favorably to the process.
Production Increase
As can be seen by the results obtained, the increase of production obtained by HDT of the mixture of vegetable hydrocarbon oil with a normal load of mineral hydrocarbon oil is linked to cases in which low availability of mineral oil prevents the complete fulfillment of the production and the consumer market demands. By using this process, the C10-C13 production is increased as well as the production from the C13+ stream (that is used as drilling fluid). Graphs 2 and 3 below show the percentage of production increase of N-paraffins (C10-C13 and C13+, respectively) according to the addition of different concentrations of vegetable oil to kerosene.
The description of this process, as well as the Figures, Graphs and Tables that accompany this document, prove the excellence of this invention in the sense of present a process where the addition of an amount of a natural oil or natural fat to a load of petroleum hydrocarbon in hydrotreatment processing.
The process of this invention overcomes problems resulting from the need for an increase in production of N-paraffins in situations in which kerosene availability is limited by the capacity of refining in the operational unit, offering alternative of inputs in which normal processing will produce N-paraffins with improved characteristics besides an increase in weighting that results in economical advantages in final results. Also, it is possible to adapt the nature of the vegetable oil used for refinery purposes in terms of the C10-C13 content of N-paraffin product obtained, and that also provides an increase in the production of C13+, which may reach double that which would be obtained by using pure kerosene. The production of C13+ is valuable as a production asset, due to the fact that its qualities make it a product used in the petroleum industry as drilling fluid.
Although this invention has been presented in its preferred implementations regarding some of the compositions of the mixture of kerosene and vegetable oil load to be submitted to hydrotreatment, and the specification described so far be considered to be sufficient to allow those well versed in the technology to put the invention into practice, This inventive process is not limited in its scope to the examples presented, since these are intended to be just an illustration and serve as a base for other modifications and alterations introduced into the context of the inventive concept, which may be practiced, as long as they do not deviate from the essential concept.
Vegetable oils of other types that are functionally equivalent and comply with the fundamental requirements of use in this invention are considered covered by the scope of this invention, and are placed within the spirit of the scope of the invention.
In this way, various modifications of the invention as far as to the nature and range of vegetable/mineral hydrocarbon oil content to be used in mixtures of vegetable/mineral hydrocarbon oil, in addition to those presented and described here, will become clear for those well versed in the technology from the description presented, which will be experienced according to the increase in N-paraffins fractions aiming at economic gains according to their destinations and industrial uses. Such changes are introduced into the scope of the attached claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| PI 0601403-8 | Apr 2006 | BR | national |
