ES2261375T3 - COOLING OF A DEPARAFINED REACTOR WITH HEAVY DEPARAFINED PRODUCT RECYCLING. - Google Patents

Abstract

A catalytic dewaxing process comprising contacting a paraffinic paraffinic hydrocarbon feed with hydrogen, in the presence of a dewaxing catalyst in a catalytic dewaxing zone, under conditions of high temperature and pressure effective for hydrogen to react with said feed and produce a dewaxed product of reduced pour point, which includes a heavy fraction 426, 7 ° C + (800 ° F +) from the dewaxer, separating and cooling at least a fraction of said heavy fraction, and passing it again through said area of Dewaxed as a cooling liquid for temperature control.

Description

Cooling of a dewaxing reactor with recycling of heavy dewaxed product.

Description Background Field of the Invention

The invention relates to a process for cooling a dewaxing reactor with dewaxing product heavy recycled. More particularly, the invention relates to catalytic dewaxing or a paraffin hydrocarbon fraction highly paraffinic from synthesis Fischer-Tropsch, in which the temperature of the exothermic dewaxing reaction is controlled by recycling of heavy dewaxed product to the reactor, such as liquid from cooling.

Background of the invention

It has been found recently that they can produce solvent fuels and premium lubricating oils from high quality from Fischer-Tropsch paraffin and hydrotreated oily paraffin. Paraffin Fischer-Tropsch is a term used for describe paraffinic hydrocarbons produced by a process of synthesis of Fischer-Tropsch hydrocarbons in the which a synthesis gas feed comprising a mixture of H2 and CO reacts in the presence of a catalyst Fischer-Tropsch, in effective conditions to form hydrocarbons Typical processes to produce these products from High quality from paraffin include two or more of fractionation, hydroisomerization and dewaxing, particularly catalytic dewaxing. Sometimes it is necessary hydrotreatment before hydroisomerization, particularly in the case of oil-derived oily paraffins. For example, U.S. Patent 4,963,672 describes a process to convert Fischer-Tropsch paraffinic hydrocarbons in a lubricant base material that has a high viscosity index (VI) and a low pour point due to successive operations of hydrotreatment, hydroisomerization and dewaxing with solvents European Patent Publication EP 0 668 342 A1 suggests a process to produce base lubricating oils by hydrogenation followed by hydroisomerization of a refined Fischer-Tropsch paraffin, followed by dewaxed. Hydrogenation is performed without cracking, to reduce the hydroisomerization temperature and increase the life of the catalyst, being known to those skilled in the art that both factors are adversely affected by the presence of oxygenated compounds and heteroatoms in food paraffin

Summary of the invention

The invention relates to dewaxing catalytic of a paraffinic hydrocarbon feed (as far as successive "paraffin feeding"), where the temperature of the exothermic dewaxing reaction is controlled by recycling of the heavy dewaxed product to the reactor, as a liquid Cooling. The paraffin feed is dewaxed catalytically by reaction thereof with hydrogen in the presence of a temperature and pressure dewaxing catalyst high. Paraffin is understood as a material that includes hydrocarbons that solidify under normal conditions of environmental temperature and pressure of 24ºC (75ºF) and 101.3 kPa (1 atm). The heavy dewaxed product is that fraction of the dewaxed paraffin feeding that has a point of initial boil in the range from approximately 426.7 at 510 ° C (800 to 950 ° F) and preferably at minus 454ºC (454ºC +) (850ºF (850ºF +)). At least a portion of this heavy dewaxed product separates from dewaxed product total and cools to a temperature sufficient to control the temperature in the catalytic dewaxing zone, but not lower to its cloud point. The product has been found heavy dewaxed recycled reacts very little, if any, with the hydrogen in the dewaxing zone and therefore does not provide a significant amount of heat to the exothermic reaction of dewaxed. The paraffin feed will contain at least 15, preferably at least 25 and more preferably at least 35% by weight of hydrocarbons having an initial boiling point from about 426.7 ° C to 510 ° C (800 to 950 ° C) and preferably at least 454.4 ° C (850 ° C). At least 50% by weight and preferably at minus 90% by weight of the paraffin feed fed at dewaxing reactor will have an initial boiling point in the range of 343-399 ° C (fraction 343-399ºC +) (650-750ºF (fraction 650-750ºF +)), with a final boiling point of at minus 565.5 ° C (1050 ° F) and preferably greater than 565.5 ° C (1050ºF). A preferred paraffin feed comprises Fischer-Tropsch synthesized hydrocarbons highly paraffinic, which have undergone hydroisomerization. Others less preferred paraffinic hydrocarbons, such as Oily paraffin derivatives and hydrocracked materials, se they treat by extraction and / or catalytic hydrorefin to separate the non-paraffinic hydrocarbons such as aromatic and other unsaturated, together with compounds containing heteroatoms, in order of producing a paraffin feed. Paraffin feeding resulting from these treatments is typically fed to dewaxer, without an intermediate hydroisomerization stage. He Dewaxed product is fractionated to separate and cool at least a portion of the heavy dewaxed product for recycling as cooling liquid, together with useful product fractions lubricants and fuels

Thus, the invention relates to a process dewaxing catalyst comprising contacting a paraffinic paraffinic hydrocarbons feed with hydrogen, in the presence of a dewaxing catalyst in a catalytic dewaxing zone, under temperature conditions and high pressure effective for hydrogen to react with said feed and produce a dewaxed product of point of reduced fluidity, which includes a heavy fraction, separate and cool at least a portion of said heavy fraction, and pass it from again to said dewaxing zone as a cooling liquid for temperature control. More specifically, the invention comprises a catalytic dewaxing process in the which a paraffin feed, which comprises hydrocarbons that have an initial boiling point in the range of 343-399ºC (650-750ºF), and that includes a fraction 426.7 ° C + (800 ° F +) reacts with hydrogen in presence of a dewaxing catalyst in an area of dewaxed at elevated temperature and pressure, to produce a dewaxed product of reduced pour point containing a fraction 426.7 ° C + (800 ° F +), followed by separation of at least one portion of fraction 426.7 ° C + (800 ° F +) of dewaxed product and cooling to a temperature above its point of cloudiness and below the dewaxing temperature, and Recycling of the cold dewaxed product to the dewaxing zone as a cooling fluid, to reduce the temperature in the area dewaxing In a preferred embodiment, the invention is refers to a process to dewax paraffinic hydrocarbons of Fischer-Tropsch synthesis by hydroisomerization of hydrocarbons in order to form a hydroisomerized product comprising a paraffin feed containing a fraction 426.7ºC + (800ºF +), catalytically dewaxing the feed for form a dewaxed product of reduced pour point, separate at least a portion of a heavy fraction 426.7 ° C + (800ºF +) of the dewaxed product, cool at least a portion of the heavy fraction and pass it back to the area of dewaxed as a cooling liquid. In one more embodiment detailed, the invention comprises an integrated process for synthesize a fraction of paraffinic hydrocarbons of nature paraffin, from a synthesis gas comprising a mixture of H2 and CO, hydroisomerize said paraffin fraction to form a hydroisomerized product and catalytically dewax said hydroisomerized product in a dewaxing zone, for form a dewaxed product of reduced pour point which contains a fraction of heavy dewaxed product, a portion from which it cools and is used as a cooling liquid in said dewaxing zone, said process comprising:

(a) reacting said mixture of H2 and CO in the presence of a catalyst for hydrocarbon synthesis Fischer-Tropsch that contains a component cobalt catalyst, under effective reaction conditions for form paraffinic paraffinic hydrocarbons of high nature purity, at least a portion of which are liquids in said reaction conditions;

(b) pass said paraffinic hydrocarbons to a hydroisomerization reaction zone;

(c) react said hydrocarbons paraffin with hydrogen in the presence of a catalyst dual function hydroisomerization in said reaction zone of hydroisomerization to form a hydroisomerized product that comprises hydrocarbons that have an initial boiling point in the range of 343-399 ° C (650-750ºF) and a boiling end point of at minus 565.5 ° C (1050 ° F);

(d) catalytically dewaxing said product hydroisomerized in a catalytic dewaxing zone for reduce its pour point, by reacting it with hydrogen to high temperature and pressure, in the presence of a catalyst that comprises a catalytic metal component of Group VIII and a crystalline aluminosilicate component, to form a product dewaxing comprising hydrocarbons having a point initial boiling above and below said point of initial boiling in the range of 343-399 ° C (650-750ºF), which includes heavy hydrocarbons that they have an initial boiling point in the range of 426.7-510 ° C (800-950 ° F);

(e) separate at least a portion of said heavy hydrocarbon dewaxed product of the rest of said dewaxed product;

(f) cool at least a portion of said dewaxed product of heavy hydrocarbon separated to a temperature below that existing in said dewaxed zone catalytic, and

(g) pass said material again dewaxed cooled to said dewaxing reaction zone As a cooling liquid.

In a preferred embodiment, the process Fischer-Tropsch is a process of synthesis of mud phase hydrocarbons in which H 2 and CO react in a sludge comprising a liquid of hydrocarbon sludge, gas bubbles and a hydrocarbon synthesis catalyst consisting of particles, and the sludge liquid comprises synthesized hydrocarbons that are liquid under the conditions of reaction. The sludge liquid is removed from the synthesis reactor of Fischer-Tropsch hydrocarbons and passes to the area of the hydroisomerization reaction in step (b).

Brief description of the drawings

Figure 1 is a schematic flow chart of a dewaxing process useful in the practice of invention.

Figure 2 is a schematic flow chart of a hydrocarbon synthesis process Fischer-Tropsch in the mud phase that includes a dewaxing process according to the practice of invention.

Detailed description

Hydroisomerization and other hydroconversion processes convert a part of the 343-399ºC + (650-750ºF +) hydrocarbons into hydrocarbons that boil below the 343-399ºC (650-750ºF) range, 343-399ºC- (650-750ºF-). While this lower boiling point material may remain in the hydroconverted material (eg, the
hydroisomerized), it is preferred to remove it before dewaxing to minimize the size of the dewaxing reactor and the amount of dewaxing catalyst needed. The removal of the lower boiling point components can be carried out, for example, by sudden gross vaporization and / or fractionation before dewaxing. The choice is determined by the expert. The lower boiling point components can be used for fuels. The dewaxed product is separated into various desired fractions, as set forth above, and typically includes, in addition to the fraction 454.4 ° C + (850 ° F +), more than one lubricant base material (fraction). By lubricant base material is meant all or part of the dewaxed product 343-399 ° C + (650-750 ° F +) produced by the process of the invention. As those skilled in the art know, a lubricant base material is an oil that has lubricating qualities, which boils in the general range of lubricating oils and is useful for preparing various lubricants such as lubricating oils and greases.

Dewaxing is conducted to convert not more than 40% by weight and in a proportion limited preferably to no more than 30% by weight of the hydroisomerized product 343-399ºC + (650-750ºF +) in material 343-399ºC- (650-750ºF-). The grade conversion will depend on the dewaxing catalyst, as well as from the feed to the dewaxer. In contrast to the process described in U.S. Pat. 4,963,672 referenced previously, due to the very low or zero concentration of nitrogen and sulfur compounds and the very low level of compounds oxygenated in paraffinic hydrocarbons produced by the Fischer-Tropsch process, hydrogenation or hydrotreatment for elimination of heteroatoms, aromatics and other unsaturated is not normally necessary before the hydroisomerization to form the paraffin feed. Additionally, the only compounds that contain heteroatoms present in any amount in the hydrocarbons of the synthesis Fischer-Tropsch comprise oxygenated materials. These oxygenated compounds are present fundamentally and in their most in the 204ºC- (400ºF-) hydrocarbons, which are separated easily from the heaviest hydrocarbons. If the hydrocarbons Paraffinous Fischer-Tropsch 343-399ºC + (650-750ºF +) contain less than, e.g., 5% by weight of hydrocarbons 204 ° C- (400 ° F-), no hydrotreatment is typically required before the hydroisomerization to produce paraffin feed. This This is not the case for an oil-derived oily paraffin, which may contain appreciable amounts of compounds that contain heteroatoms, particularly those that contain sulfur and nitrogen, as well as aromatic and other unsaturated compounds. The Typical hydrotreatment catalysts include the good known hydrotreatment catalysts such as Co / Mo or Ni / Mo on alumina. Other hydrotreatment catalysts include combinations of Co and / or Ni and Mo and / or W on a basis of silica / alumina Such catalysts are typically sulfurized. Hydrotreated hydrocarbons are released from volatile materials to remove H2S, water, nitrogen and other species that deactivate the catalyst, before dewaxing. Terms typical for the hydrotreatment of oily paraffin e hydrocracked hydrocarbons in order to form a feed paraffin for dewaxing include temperatures included in the range from about 232 to 426.7 ° C (450 to 800ºF), a hydrogen pressure between approximately 2758 and 17237 kPa (400 and 2500 psia), a space velocity between approximately 0.5 and 3 V / V / h (power volume / power volume catalyst per hour), and a flow of hydrogen gas that goes from approximately 89 to 890 lN / l (500 to 5000 scf / b).

Paraffin feeding includes preferably the entire fraction 343-399 ° C + (650-750ºF +) of, or (i) an oily paraffin hydrotreated or hydrocracked material from which the compounds containing heteroatoms, aromatics and others unsaturated and preferably hydroisomerized before dewaxed and (ii) hydroisomerized paraffinic hydrocarbons formed by a process of hydrocarbon synthesis, being determined the initial cut-off point between 343ºC and 399ºC (650ºF and 750ºF) by the expert technician and its end point being determined exactly, preferably above 565.5 ° C (1050 ° F), by feed, catalyst and process variables used for the synthesis The paraffin feed may also contain boiling material at lower temperature, 343-399ºC- (650-750ºF-), in case wanted. While this lower boiling point material does not It is useful for a lubricant base material, when it comes to according to the process of the invention it is useful for fuels The paraffin feed also includes more than 90% and typically more than 95% paraffinic hydrocarbons and this is what is meant by "paraffinic" in the context of the invention. Most of the hydrocarbons contained in the Fischer-Tropsch paraffin are normal paraffins. Paraffin feeds derived by hydroisomerization of a paraffin fraction Fischer-Tropsch have insignificant amounts of sulfur and nitrogen compounds (e.g., less than 1 ppm by weight). Paraffin feeds Fischer-Tropsch that have these properties and are useful in the process of the invention have been derived from the fraction paraffin produced by a Fischer-Tropsch process in the mud phase, with a catalyst that has a component Cobalt Catalytic In the practice of the invention, it is preferred use a hydrocarbon synthesis process Fischer-Tropsch in the mud phase for the synthesis of paraffin feeding and particularly one that employs a Fischer-Tropsch catalyst comprising a cobalt catalytic component, in order to provide a factor high alpha to produce higher molecular weight paraffins more desirable

The practice of the invention is not limited to use. of any particular dewaxing catalyst, but can be practiced with any dewaxing catalyst that reduce the pour point of the paraffin feed, and preferably a catalyst that produces a reasonable yield of the desired dewaxed product fractions. Such catalysts comprise at least one metallic catalyst component and an acidic refractory metal oxide component. He metallic catalyst component may comprise one or more compounds or metals of Group VIII of the Periodic Table of Elements and preferably at least one noble metal component, such as, but not limited to, platinum. The Groups to be referenced in this report refer to Groups such as They are found in the Periodic Table of the Elements Sargent-Welch registered as literary property in 1968 by the Sargent-Welch Scientific Company. He refractory metal oxide component preferably comprises at least one crystalline aluminosilicate and preferably at least a zeolite These include molecular sieves morpho-selective that, when combined with at minus a metallic catalytic component, it has been shown that they are paraffin dewaxing tools Fischer-Tropsch and oily paraffins and include, for example, mordenite, ZSM-5, ferrite, ZSM-11, ZSM-23, ZSM-35, ZSM-22 also known such as theta-one or TON, and silicoaluminophosphates known as SAPO's (document 5,135,638). Dewaxing can be carried out with the catalyst in a fixed bed, fluid or in phase of mud. Typical dewaxing conditions include a temperature in the range from about 204 to 315.5ºC (400 to 600ºF), a pressure of 3447-17237 kPa (500-2500 psig), hydrogen treatment flow  178-890 lN / l (1000-5000 SCF / B) for continuous flow and LHSV reactors of 0.1-10, preferably 0.2-2.0. The dewaxing is typically performed to convert no more than 40% by weight and preferably not more than 30% by weight of the product hydroisomerized 343-399 ° C + (650-750ºF +) in boiling material lower.

A dewaxing catalyst is preferred which it comprises a catalytic platinum component and a component that comprises the hydrogen form of mordenite (Pt / H-mordenite), particularly for dewaxing of a paraffin feed derived from the process Fischer-Tropsch This is because it has found that not all catalysts and conditions of Dewaxing are equivalent, when used to dewax  these hydroisomerized materials very pure and highly paraffinics, due to cracking reactions that take place during dewaxing. These cracking reactions produce lower boiling material. For example, the Patent U.S. 3,539,498 states that by using 0.5% by weight of platinum on mordenite H for dewaxing of a feed of Distilled light lubricating oil 315.5-371 ° C (600-700ºF) to a pour point of -23ºC (-10ºF), the product yield was only 68% by volume. The U.S. Patent 4,057,488 cites a 65.5% volume return, using platinum on mordenite H, to dewax a material denitrogenated refining boiling between 393.3 and 510 ° C (740-950ºF). Surprisingly and unexpectedly, it has found that by the use of Pt / H-mordenite to dewax a feed Hydroisomerized Fischer-Tropsch paraffin that boils in the range of lubricating oils (e.g., 343-399ºC + (650-750ºF +)), it is not produce these high conversion levels in hydrocarbons of lower boiling point. When a noble metal is used, the noble metal load, based on the combined weight of the mordenite and the noble metal will be between approximately 0.1 and 1.0% by weight and preferably between 0.3 and 0.7% by weight, comprising the noble metal preferably Pt. Another metal can be used noble, Pd, in combination with the Pt. It has been found that a combination of a dewaxing catalyst Pt / H-mordenite with a paraffin feed hydroisomerized derived from a process Fischer-Tropsch that employs a catalyst that it comprises a catalytic component of cobalt, it resulted in a lower pour point for a given conversion level, which the same catalyst with a refined paraffin material derived from a petroleum oil This is unexpected.

During the hydroisomerization of paraffinic hydrocarbons to obtain the paraffin feed, the conversion of hydrocarbons 343-399 ° C + (650-750ºF +) in hydrocarbons 343-399ºC- (650-750ºF-), may be  between about 20 and 80% by weight, preferably between 30 and 70% and more preferably between about 30 and 60% by weight, based on a single step of feeding through The reaction zone. The paraffin feed may contain smaller amounts of material 343-399 ° C (650-750ºF-) before hydroconversion and at least a portion of this lower boiling material is will also become boiling point components even more low. Typical conditions of the hydroisomerization reaction they include a temperature and pressure typically between 149-482ºC (300-900ºF) and 0-17237 kPa (0-2500 psig), with preferred ranges of 288-399 ° C (550-650ºF) and 2068-8274 kPa (300-1200 psig), respectively. The flow rates of hydrogen treatment are 89-890 lN / l (500-5000 SCF / B), with a preferred range of 356-712 lN / l (2000-4000 SCF / B). He hydroisomerization catalyst comprises one or more components Group VIII catalytic metals, and preferably one or more non-noble metals, such as Co, Ni and Fe, which will also include typically an oxide promoter of a Group VIB metal (e.g., Mo or W), supported on a metal oxide support of character acid to give the catalyst both a hydrogenation function to hydroisomerize hydrocarbons and an acid function of hydrocracking The catalyst may also contain a metal of Group IB, such as copper, as a hydrogenolysis suppressant. The catalyst cracking and hydrogenation activity is determined by its specific composition, as is known. In a preferred embodiment, the catalytically active metal comprises cobalt and molybdenum. The acid oxide carrier or vehicle can include silica, alumina, silica-alumina, silica-alumina-phosphates, dioxide titanium, zirconium oxide, vanadium oxide, and other oxides of Groups II, IV, V or VI, as well as Y sieves, such as Y sieves ultra-stable Preferred brackets include silica, alumina and silica-alumina and, more preferably, a silica-alumina in which the silica concentration in the bulk support (as opposed to the surface silica) is less than about 50% by weight, preferably less than 35% by weight and more preferably 15-30% by weight. As is known, if the support is alumina, small amounts of fluorine or chlorine can be incorporated into the same to increase acid functionality. The surface specific support will be in the range that goes from about 180 to 400 m2 / g, preferably 230-350 m2 / g, with a pore volume, bulk density and resistance to cross crushing respective ranges in the range of 0.3 to 1.0 ml / g and preferably 0.35-0.75 ml / g; 0.5-1.0 g / ml, and 0.8-3.5 kg / mm. A particularly preferred hydroisomerization catalyst comprises cobalt, molybdenum and optionally copper, on a support amorphous silica-alumina containing approximately 20-30% by weight of silica. The Preparation of these catalysts is well known and well documented. Illustrative, but not limiting examples of such catalysts, their preparation and use can be found, for example, in U.S. Pat. 5,370,788 and 5,378,248.

A hydroisomerization catalyst that is particularly preferred in the practice of the invention comprises both cobalt and molybdenum catalytic components supported on an amorphous silica-alumina stand with bass silica content, and most preferably one in which the cobalt component is deposited on the support and calcined before adding the molybdenum component. This catalyst it will contain 10 to 20% by weight of MoO3 and 2-5% by weight of CoO on an amorphous support of alumina-silica in which the silica content ranges between 20 and 30% by weight of the support. It has been found that this catalyst exhibits satisfactory retention of selectivity and good resistance to deactivation by oxygenated compounds found in paraffin feeds produced by the Fischer-Tropsch process. The addition of a component Copper suppresses hydrogenolysis. The preparation of this catalyst is described, for example, in U.S. Pat. 5,757,920 and 5,750,819, whose descriptions are incorporated herein memory by reference.

Referring to Figure 1, a Simple schematic flow chart of a dewaxing unit 10 and a process useful in the practice of the invention. So, it shows a hydroconversion reactor 12, a dewaxing reactor catalytic 14 and a vacuum distillation tower 16. Associated with these are three sudden vaporization drums 18, 20 and 22, and two heat exchangers 24 and 26. A paraffin fraction of Paraffinic hydrocarbons are fed, by pipe 28, to a hydroconversion reactor 12. The paraffin fraction has a initial boiling point in the range of 343-399ºC (650-750ºF) and boil continuously to a boiling end point greater than 565.5 ° C (1050ºF). The reactor 12 can be a hydrogenator, a hydrotreator or a hydroisomerizer. In the hydroconversion reactor, the descending paraffin feed reacts with hydrogen also descending that enters the reactor through pipe 30, in presence of a suitable catalyst in a fixed bed of catalyst 32. For purposes of illustration, the paraffin fraction it will be the one produced by a hydrocarbon synthesis process Fischer-Tropsch in mud phase and reactor 12 It will be a hydroisomerization unit. The catalyst of hydroisomerization in reactor 12 contains 10-20% by weight of MoO 3 and 2-5% by weight of CoO on a amorphous alumina-silica support component in the which silica content is between 10 and 30% in weight. The reaction conditions include a temperature and a hydrogen pressure of 378ºC (713ºF) and 4999 kPa (725 psig). During hydroisomerization, approximately 40% by weight of the feed becomes a fraction of hydrocarbons more light boiling below the initial boiling point of the paraffin fraction, the remaining 60% by weight comprising the heavier hydroisomerized feed for the operation of dewaxed. The hydroisomerized hydrocarbons are removed from the bottom of the reactor through pipe 34 and pass to a drum of simple separation 18, in which lighter hydrocarbons are removed as head steamers, through pipe 36. This separation may also include a fractionation column (not represented) for the separated liquid, before passing the same to the dewaxing unit located downstream. The heavier paraffin feed is removed from drum 18 in the form liquid and passes, through pipe 38, to the dewaxing reactor catalytic 14. The reactor 14 contains a fixed bed 40 of dewaxing catalyst comprising 0.5% by weight of Pt on H-mordenite Hydrogen or a gas of treatment containing hydrogen in the reactor through line 42. Dewaxing conditions in the reactor include a temperature of approximately 288ºC (550ºF) and a pressure of hydrogen of approximately 4999 kPa (725 psig). feeding paraffin reacts with hydrogen in the presence of the catalyst dewaxing, which reduces its pour point and converts some of the feed in boiling material lower. Approximately 20% by volume of the feed paraffin becomes lower boiling material during dewaxing. Dewaxed hydrocarbons are removed from the dewaxing reactor through the pipe 44 and passed to a sudden evaporator 20, which operates at a lower pressure than the dewaxing reactor. The sudden evaporator is also a type of simple drum separator. The lighter material is removed as head steam through the pipe 46. The dewaxed product 343-399 ° C + (650-750 ° F +) remaining removed by pipe 48 and passed to the distillation tower 16, in which it is divided into the desired number of lubricant and fuel fractions, as shown. The fumes head are made to pass, through pipe 55 through a changer of heat 24, in which a part of the hydrocarbon vapors they condense and the resulting liquid and vapor mixture is made pass through the pipe 25 to the separation drum 22. The steam and the liquid separates, removing steam by head, through the pipe 27, and the condensate being returned again, through the pipe 23, to the top of the tower as reflux. A portion of the liquid of heads (23A) is removed as a stream of light product, the which can be used as a base material for light lubricants or As fuel. Less than 10% by volume of the feed that goes to distillation tower through pipe 48 becomes a Lightweight vacuum diesel fraction, suitable for use as Diesel. This is removed from the tower by pipe 50. Approximately 25% by volume is removed, through pipe 52, as base material for automatic transmission fluids. Approximately 50% by volume of the dewaxed distillate is removed through pipe 54, as a lubricant fraction useful as a base material for passenger car engine oils (crankcase oil motor). The remaining 25% in volume is a fraction of material heavy lubricant base, which is removed from the bottom of the tower, by the pipe 56. This has an initial boiling point comprised in the range of 426.7-454.4 ° C (800-850ºF) and an end point of approximately 617 ° C (1142 ° F). Approximately 75% by volume of this product heavy dewaxing is passed, through pipe 58, for its further processing in a heavy lubricant for applications industrial oils and / or heavy motor oils. 25% by volume  remaining is conducted, by pipe 60, to and through the heat exchanger 26, in which it is cooled to a temperature below 288ºC (550ºF), and then through pipes 62, 64 and 66 to reactor 14 as cooling liquid. How I know demonstrate in the following example, this cooling liquid does not seems to react with hydrogen in the presence of the catalyst dewaxed to a significant extent, for reasons that are not well known. The use of this recycled cold dewaxed product maintains the dewaxing reactor at the desired temperature of 288ºC (550ºF), without using cold food, a gas cold, another cold hydrocarbon liquid that could dilute the dewaxed product and food, or a system of indirect heat exchange.

Figure 2 is a schematic flow chart of an integrated hydrocarbon synthesis process useful in the practice of the invention, which includes hydroisomerization and dewaxing of a paraffin fraction from synthesis Fischer-Tropsch The same numbers in Figure 2 they refer to the same reactors, heat exchangers, separators, pipes and distillation tower as in Figure 1. Referring to Figure 2, the integrated unit 100 it comprises a mud phase hydrocarbon synthesis reactor 110 which contains a three-phase sludge 112 inside, has a gas distribution plate 114 at the bottom of the sludge to inject synthesis gas from the area of the lower collecting chamber, and liquid filtration media indicated as box 116, submerged in the mud. The synthesis gas, which comprises a mixture of H2 and CO in a molar ratio of 2.1: 1, is passed to reactor through pipe 118, the liquid separating continuously sludge, which comprises synthesized hydrocarbons that are liquids under reaction conditions, as filtered by the pipe 120 and the gaseous effluent being removed from the reactor by head as waste gas through pipe 122. The filtrate, which it comprises synthesized hydrocarbons that are liquid in the reaction conditions, and containing the boiling fraction 343-399ºC + (650-750ºF +), is made pass to a hydroisomerization reactor 12, which is the same as in Figure 1 and has the same catalyst inside. At hydrocarbon synthesis reactor 110, H 2 and CO of the gas of synthesis react in the presence of the particulate catalyst to form the desired hydrocarbons, most of the which comprise the sludge liquid, together with gaseous products of the reaction, much of which is water vapor and CO 2. The circles in 112 represent the gas bubbles of synthesis and gaseous products, while solid points represent the hydrocarbon synthesis catalyst Particulate Fischer-Tropsch. Gaseous heads comprise water vapor, CO2, hydrocarbon products gaseous, unreacted synthesis gas and low amounts important of oxygenated compounds. The heads are passed to through respective heat exchangers hot and cold 124 and 126, in which they cool to condense a portion of water and hydrocarbons, and to respective separators hot and cold 128 and 130, in order to recover liquid hydrocarbons condensed Thus, the head gas is passed through the pipe 122 through a hot heat exchanger 124 to separate by condensation of some water vapor and heavier hydrocarbons in liquid form, then passing the mixture of gas and liquid by pipe 132 to separator 128, in which water and liquid hydrocarbons are separated from the remaining gas as layers separated liquids. The water layer is removed by pipe 134 and liquid hydrocarbons are removed by pipe 136 and pass to the hydroisomerization unit 12, together with the filtrate from  of filter 116. The separated liquid hydrocarbon from the hot separator 128 contains hydrocarbons that solidify in normal ambient temperature and pressure conditions, and are useful as part of the paraffin feed to the unit of hydroisomerization 12. The uncondensed gas is removed from the separator 128 and passes through pipe 140 through the cold heat exchanger 126, to condense more water and light hydrocarbons into shape liquid, then posing the mixture of gas and liquid through the pipe 142 to cold separator 130, in which the liquid separates of the uncondensed gas as two separate layers. The water is removed by pipe 144 and liquid hydrocarbon by pipe 146 and to through the pipe 34. The non-condensed vapors are removed by head through pipe 150. Hydrogen or a gas is passed hydrogen containing treatment to the top of the unit of hydroisomerization through the pipeline 30. Hydrocarbons suffer hydroisomerization and the mixture of hydroisomerized hydrocarbons and gas is removed from the reactor through pipe 34 and passes along with the lighter hydrocarbons from pipe 146, at a fractionator 156, which operates at atmospheric pressure or higher, in which the lighter components are separated as fractions fuels, such as a fraction of gasoline removed by the pipe 158, and a fuel fraction of turbojet / diesel removed by pipe 160, withdrawing the unreacted hydrogen from 138 and hydrocarbon gas Light as queue gas through pipe 162. The hydroisomerized more heavy, which comprises the desired hydrocarbons that boil in the range of lubricating oils that have a point of initial boil in the range from 343 to 399ºC (650-750ºF), is removed from the bottom of the fractionator through the pipe 164. Thus, in this embodiment, the lighter portion of the hydroisomerized product is separated from the lubricating oils material before dewaxing. This reduces notably the load on both the dewaxing unit and over the subsequent vacuum tube distiller. The fraction of lubricating oil that has an initial boiling point of approximately 371ºC (700ºF) and an end point greater than 565.5ºC (1050ºF), pipe 164 is passed to a unit of catalytic dewaxing 14, which contains a fixed bed 40 of a dewaxing catalyst comprising Pt / H-mordenite. It is passed hydrogen or a gas of hydrogen containing treatment to the top of the reactor dewaxing 14 through the pipe 42, and reacts with the product hydroisomerized to reduce its pour point and produce a dewaxed product comprising a base material of lubricants, which is removed, together with unreacted hydrogen and the gaseous products of the dewaxing reaction, by the pipe 44, is passed through a fractionator of simple sudden vaporization 20 to remove steam and gas as heads, and then to the vacuum distillation tower 16, by the pipe 48. As in the case of hydroisomerization, the Catalytic dewaxing also results in some of the base stock material is cracked to a material that boils at lower temperature, to form a light fraction. At tubular vacuum distiller, the light fraction is separated from the dewaxed base material and is removed from the unit by the pipe 158, removing the lubricating base material from the unit dewaxed by pipe 56. Although only one is shown single base stock stream for convenience, in most cases a plurality of base viscosity stocks occur different by vacuum fractionation. Hydrocarbon gases  light and any remaining amount of unreacted hydrogen they are removed by head through pipe 80. Most (e.g., more 50%) of the heavy base stock is removed by pipe 58 and sends to further processing in various lubricants. The rest is passed, through the pipe 60, to and through the changer of heat 26, in which it is cooled to a temperature sufficiently below the temperature in the reactor of dewaxed to be used as a cooling liquid. This cold cooling liquid is passed through pipes 62, 64 and 66, back to the dewaxing reactor, in which it does not reacts with the hydrogen in the reactor in a proportion that impair its effectiveness as a cooling liquid.

While types of reaction catalyst Suitable Fischer-Tropsch comprise, for example, one or more Group VIII catalytic metals such as Fe, Ni, Co, Ru and Re, in the process of the invention it is preferred that the catalyst comprises a catalytic component of cobalt. In a embodiment, the catalyst comprises catalytically amounts Effective Co and one or more of Re, Ru, Fe, Ni, Th, Zr, Hf, U, Mg and La on a suitable inorganic support material, preferably one comprising one or more refractory metal oxides. Brackets Preferred for Co-containing catalysts comprise particularly titanium dioxide. Useful catalysts and their preparation are known and illustrative, but can be found non-limiting examples, for example, in U.S. Pat. 4,568,663; 4,663,305; 4,542,122; 4,621,072 and 5,545,674. In a Mud phase hydrocarbon synthesis process, which is a type of hydrocarbon synthesis process Fischer-Tropsch preferred in the practice of invention, a synthesis gas comprising a mixture of H2 and CO is bubbled as a third phase through a mud in a reactor comprising a hydrocarbon synthesis catalyst of dispersed particulate Fischer-Tropsch type and suspended in a liquid mud comprising products hydrocarbons of the synthesis reaction that are liquid in the reaction conditions The molar ratio of hydrogen to monoxide Carbon can vary in general from approximately 0.5 to 4, but more typically within the range ranging from about 0.7 to 2.75 and preferably from approximately 0.7 to 2.5. The stoichiometric molar ratio for a hydrocarbon synthesis reaction Fischer-Tropsch is as a rule approximately 2.0, but in a hydrocarbon synthesis process In the mud phase it is usually about 2.1 / 1 and can be increased to obtain the desired amount of hydrogen at starting from the synthesis gas for a reaction other than the reaction of synthesis Mud phase process conditions vary in a certain degree, depending on the catalyst and the desired products. In the practice of the invention, it is preferred that the reaction of hydrocarbon synthesis is conducted under conditions in which little or none of the gas displacement reaction of water and more preferably without taking place at all water gas displacement reaction during the synthesis of hydrocarbons It is also preferred to conduct the reaction in conditions that give an alpha factor of at least 0.85, preferably  at least 0.9 and more preferably at least 0.92, in order to synthesize a greater amount of weight hydrocarbons top molecular most desirable. This has been achieved in a mud phase process that uses a catalyst that contains a Cobalt Catalytic Component Those skilled in the art know that the alpha factor means the kinetic alpha factor of Schultz-Flory. Typical effective conditions for produce hydrocarbons that comprise mostly paraffins C_ {5+}, (e.g., C_ {5 +} - C_ {200}) and preferably C 10+ paraffins (and more preferably C 20+) in a hydrocarbon synthesis process in phase of sludge that employs a catalyst comprising a component of Cobalt supported include, for example, temperatures, pressures and hourly space velocities of gas in the range ranging from about 160-315 ° C (320-600ºF), 552-4.134 kPa (80-600 psi) and 100-40,000 V / h / V, expressed as standard volumes of gas mixture of CO and H2 (0 ° C, 101.3 kPa (1 atm)) per hour and per volume of catalyst, respectively. Hydrocarbons that are liquid in the reaction conditions are removed from the reactor using means of filtration.

The invention will be more fully understood with reference to the example that follows.

Example

Fischer-Tropsch synthesis

Paraffinic hydrocarbons were produced synthesized by the Fischer-Tropsch process in a mud phase reactor from a gas feed of synthesis comprising a mixture of H2 and CO that had a molar ratio of H2 to CO between 2.11 and 2.16. He sludge comprised particles of a synthesis catalyst of Fischer-Tropsch hydrocarbons comprising cobalt and rhenium supported on titanium dioxide dispersed in a liquid of hydrocarbon sludge, making the gas gush out synthesis through the mud. The liquid mud included products hydrocarbons of the synthesis reaction that were liquids in the reaction conditions These included a temperature of 218 ° C (425ºF), a pressure of 4999.5 kPa (290 psig) and a speed Linear gaseous feed of 12 to 18 cm / s. The alpha factor of Synthesis step was greater than 0.9. Paraffinic hydrocarbons, that are liquid under the reaction conditions and that constitute the sludge, were removed from the reactor by filtration. The distribution of Boiling points of this paraffinic hydrocarbon liquid are given in Table 1.

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TABLE 1

Boiling Point Distribution,% by Weight of the Fischer-Tropsch Reactor Product (PEI-500ºF) PEI-260ºC 1.0 (500-700ºF)   260-371 ° C 28.1 (700ºF +) 371 ° C + 70.9 (1050ºF +) 565.5 ° C + 6.8

Hydroisomerization

The paraffin liquid was hydroisomerized without fractionation and therefore included 29% by weight of material that boiled below 371 ° C (700 ° F) shown in Table 1. The paraffin liquid was hydroisomerized by reaction with hydrogen in presence of a dual function hydroisomerization catalyst which consisted of cobalt (CoO, 3.2% by weight) and molybdenum (MoO 3, 15.2% by weight) supported on an acid component of amorphous silica-alumina cogel, 15.5% by weight of which It was silica. The catalyst had a specific surface area of 266 m2 / g and a pore volume (P.V. H2O) of 0.64 ml / g. This catalyst was prepared by deposition and calcination of the component of cobalt on the support before deposition and calcination of the molybdenum component The conditions for hydroisomerization are shown in Table 2 and selected for a 50% objective by weight of conversion of fraction 371 ° C + (700 ° F +), which is defined how:

Conv. 371 ° C + (700ºF +) = [1 - (% p 371ºC + (700ºF +) in product) / (% p 371ºC + (700ºF +) in power)] x 100

TABLE 2

Reaction Conditions Hydroisomerization Temperature, ºF (ºC) 713 (378) H 2 pressure (psig (pure)), kPa (725) 73442 Gas flow Treatment H2 (SCF / B) lN / l (2500) 445 LHSV, v / v / h 1.1 Conversion of 371ºC + (700ºF +)  target% p fifty

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As indicated in the Table, 50% by weight of the paraffin feed 371 ° C + (700 ° F +) became products with boiling point 371ºC- (700ºF-). The product hydroisomerized was fractionated to separate fractions 371 ° C + (700ºF +) and 371ºC- (700ºF-), dividing the product 371ºC- (700ºF-) hydroisomerized separated to recover products fuels with cloud point and crystallization point reduced

Table 3 shows the product properties 371 ° C + (700 ° F +) hydroisomerized comprising 86.8% by weight of hydrocarbons that boil in the range of 371-510ºC (700-950ºF) and 11.6% p of 510ºC + hydrocarbons (950ºF +).

TABLE 3

Boiling Point Distribution (degrees F), ºC, by GCD,% by weight, and pour point Material Fraction 700ºF + hydroisomerized (PEI-320ºF) PEI-160ºC 0 (320-500ºF)   160-260 ° C 0 (500-700ºF)   260-371 ° C 1.6 (700-950ºF)   371-510 ° C 86.8 (730ºF +) 388 ° C + (78.3) (950 + ºF) 510 + ºC 11.6 Pour point, ºC 2 KV @ 40 ° C, (cSt) 10-6 m 2 / s 26.25 KV @ 100ºC, (cSt) 10-6 m 2 / s 5.07 SAW 148

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Catalytic Dewaxing

The hydroisomerized product 371ºC + (700ºF +) shown in Table 3 was catalytically deparaffinized using a catalyst with 0.5% p of Pt / H-mordenite for reduce the pour point and form a lubricating base material of high VI. In this experiment a small plant unit was used upward flow pilot. Dewaxing conditions included a pressure of H2 of 5171 kPa (750 psig), with a nominal flow of treatment gas from 445 lN / l (2500 SCF / B) to 1 LHSV and a temperature of 288ºC (550ºF). The dewaxed product leaving the reactor was fractionated using distillation 15/5 standard to separate fuel components from point lower boiling produced in the dewaxing reactor and the product 371 ° C (700 ° F +) was subjected to Hivac distillation to obtain narrow cuts, determining low temperature properties  over portions of 388-510 ° C (730-950ºF) and 510ºC + (950ºF +). The results are summary in Table 4.

TABLE 4

Results of the Catalytic Dewaxing of F-T Paraffin Hydroisomerized Material Reactor temperature (ºF) ºC (550) 288 Yields,% p \ hskip0,4cm C_ {1} -C_ {4} 11.3 \ hskip0,4cm C_ {5} -320ºF 9.1 \ hskip0,4cm 320-730ºF 1.3 \ hskip0,4cm 730-950ºF 59.9 \ hskip0,4cm  950ºF + 18.4 \ hskip0.4cm Performance Total 78.3 (730-950ºF) 388-510 ° C \ hskip0,4cm Pour point, ºC 26 \ hskip0.4cm KV to 40 ° C, (cSt) 10-6 m 2 / s 17.27 KV at 100 ° C, (cSt) 10-6 m 2 / s 3.96 \ hskip0,4cm SAW 127.3 (950ºF +) 510 ° C + Pour point, ºC 7 KV at 40 ° C, (cSt) 10-6 m2 / s 80.19 \ hskip0.4cm KV at 100 ° C, (cSt) 10-6 m 2 / s 11.90 \ hskip0,4cm SAW 142.5 Stock Base 371ºC + (700ºF +) Total (dewaxed) \ hskip0,4cm Point of fluidity, ºC fifteen KV at 40 ° C at 40 ° C (cSt) 10-6 m 2 / s 22.76 KV at 100 ° C, (cSt) 10-6 m 2 / s 4.83 \ hskip0,4cm SAW 138.1

The data in Table 3 show returns of 86.8% by weight of hydroisomerized product which boiled in the range of 371-510 ° C (700-950ºF) and 11.6% by weight of product hydroisomerized 510 ° C + (950 ° F +). So, of the product hydroisomerized 371.1 ° C + (700 ° F +), the material 510 ° C + (700 ° F +) is 88.2% by weight and the material 510 ° C + (950 ° F +) is 11.8% by weight. After dewaxing, dewaxing product approximately 371 ° C + (700 ° F +), Table 4 shows that only 59.9% by weight is 371 ° C + (700 ° F +), while 23.5% by weight comprises 510 ° C dewaxed product + (950 ° F +). This therefore indicates a major conversion of product feed hydroisomerized 371-510 ° C (700-950ºF) in the hydrocarbon dewaxer boiling at a lower temperature, essentially without conversion some of the dewaxed product 510ºC + (950ºF +) in hydrocarbons They boil at a lower temperature.

This therefore proves that essentially little or none of the recycled 510ºC + (950ºF +) heavy dewaxed product (used as a cooling liquid) reacts with the dewaxing catalyst.

Claims (23)

1. A catalytic dewaxing process that comprises contacting a hydrocarbon feed paraffinics of paraffinic nature with hydrogen, in the presence of a dewaxing catalyst in a dewaxing zone catalytic, under conditions of high temperature and pressure effective so that hydrogen reacts with that feed and produce a dewaxed product of reduced pour point, which includes a heavy fraction 426.7 ° C + (800 ° F +) from dewaxer, separate and cool at least a fraction of said heavy fraction, and make it pass again through said area of dewaxed as a cooling liquid to control the temperature. 2. A process according to claim 1, in which said fraction of heavy dewaxed product has an initial boiling point in the range of 426.7-510 ° C (800-950 ° F). 3. A process according to claim 1 or 2, in which said paraffin feed comprises hydrocarbons that have an initial boiling point in the range of 343-399 ° C (650-750ºF). 4. A process according to any one of claims 1 to 3, wherein said feed paraffin has a final boiling point of at least 565.5 ° C (1050ºF). 5. A process according to any of the previous claims, wherein said feed Paraffin comprises a hydroisomerized product. 6. A process according to any of the previous claims, wherein said catalyst of dewaxing comprises at least one catalytic metal component and at least one component of microcrystalline aluminosilicate of acid character. 7. A process according to claim 6, wherein said catalytic metal component comprises the minus a Group VIII metal. 8. A process according to claim 7, wherein said metal component comprises a component of noble metal 9. A process according to claim 8, wherein said catalyst comprises Pt and H-mordenite 10. A process according to any of the previous claims, wherein said feed Paraffin is derived from hydrocarbons synthesized by the process Fischer-Tropsch 11. A process according to any of the claims 1 to 9, wherein said paraffin feed is derived from an oily paraffin or a hydrocracked material that is has tried to eliminate non-paraffinic hydrocarbons and compounds which contain hetero atoms. 12. A process according to claim 10 or 11, in which said paraffin feed has been subjected to hydroisomerization. 13. A process according to claim 1, in which the paraffin feed is derived from a process of synthesis of Fischer-Tropsch hydrocarbons that understands: (a) reacting said mixture of H2 and CO in the presence of a hydrocarbon synthesis catalyst Fischer-Tropsch that contains a component cobalt catalyst, under effective reaction conditions for form paraffinic paraffinic hydrocarbons of high nature purity, at least a portion of which are liquids in said reaction conditions; (b) pass said paraffinic hydrocarbons to a hydroisomerization reaction zone; Y (c) react said hydrocarbons paraffin with hydrogen in the presence of a catalyst dual function hydroisomerization in said reaction zone of hydroisomerization to form a hydroisomerized product that comprises hydrocarbons having an initial boiling point in the range of 343-399 ° C (650-750ºF) and a final boiling point of at minus 565ºC (1050ºF), and in which the hydroisomerized product is catalytically deparaffin in the presence of a catalyst that it comprises a catalytic metallic component of Group VIII and a crystalline aluminosilicate component, to convert a part of the hydroisomerized product in boiling material bottom and form a dewaxed product comprising hydrocarbons having a higher initial boiling point and lower than said initial boiling point in the range of 343-399ºC (650-750ºF), which includes heavy hydrocarbons that have an initial boiling point in the range of 426.7-510 ° C (800-950ºF).

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14. A process according to claim 13, in which dewaxing is conducted to convert no more than 40% by weight of the hydroisomerized product 343-399 ° C + (650-750ºF +) in boiling material lower. 15. A process according to claim 13 or 14, in which said H 2 and CO react in a phase of sludge comprising a liquid of hydrocarbon sludge, bubbles of gas and a particulate hydrocarbon synthesis catalyst and in which said sludge liquid comprises synthesized hydrocarbons which are liquids under the reaction conditions, and in which said sludge liquid is removed from said sludge, and passed to said Hydroisomerization reaction zone in step (b). 16. A process according to any of the claims 13 to 15, wherein said cooling liquid reduce the temperature in said dewaxing zone. 17. A process according to any of the claims 13 to 16, wherein said hydrocarbon fraction  synthesized paraffin includes hydrocarbons that have a point of initial boiling within said range of 343-399ºC (650-750ºF) and one point final of at least 565.5ºC (1050ºF). 18. A process according to any of the claims 13 to 17, wherein said catalyst of hydroisomerization comprises a non-metal catalyst component noble of Group VIII and an acid support. 19. A process according to claim 18, wherein said dewaxing catalyst comprises a Zeolite component and a noble metal component. 20. A process according to claim 19, wherein said dewaxing catalyst comprises Pt and H-mordenite 21. A process according to claim 19, wherein said hydroisomerization catalyst comprises a metallic catalytic component of cobalt and molybdenum and said support comprises alumina-silica that has no more 30% by weight silica. 22. A process according to any of the claims 13 to 21, wherein said sludge liquid comprises hydrocarbons 343-399 ° C (650-750ºF), at least a portion of which Remove before subjecting said liquid to hydroisomerization. 23. A process according to any of the claims 13 to 22, wherein said heavy fraction of dewaxed material has a boiling endpoint greater than 565.5 ° C (1050 ° F).