ES2331517T3 - FISCHER-TROPSCH PROCEDURE USING A FISCHER-TROPSCH CATALYST AND A CATALYST CONTAINING ZEOLITE. - Google Patents

Abstract

Fischer-Tropsch process for the conversion of carbon monoxide and hydrogen to C5<+> hydrocarbon mixtures in which process use is made of Fischer-Tropsch catalyst particles and fluid catalytic cracking (FCC) catalyst particles. The FCC catalyst can be a fresh FCC catalyst, or an equilibrium catalysts (E-cat).

Description

Fischer-Tropsch procedure which uses a Fischer-Tropsch catalyst and a catalyst containing zeolite.

The present invention relates to a Fischer-Tropsch procedure for conversion of carbon monoxide and hydrogen in hydrocarbon mixtures C 5 + using a catalyst of Fischer-Tropsch and a catalyst containing zeolite

The procedure of Fischer-Tropsch generally comprises the following procedural steps.

The first stage involves reacting a source of carbon (such as coal or natural gas) with a source of oxygen (such as water vapor, air or oxygen) to form a mixture of carbon monoxide and hydrogen, usually called synthesis gas

The second stage involves contacting the carbon monoxide and hydrogen with a catalyst Fischer-Tropsch leading to hydrocarbons and water. Depending on the process conditions and the catalyst used, the nature of hydrocarbons and chain length may vary The main products of the reaction of Fischer-Tropsch are linear paraffins and olefins and water, but limited isomerization can occur and the inclusion of heteroatoms such as oxygen. Catalysts generally applied for this second stage are catalysts containing iron and / or cobalt. In order to enhance the isomerization during this second stage, a Cocatalyst

The third stage involves the isomerization of the hydrocarbons formed in the second stage to produce products more valuable For example, the longest chains in the product they can undergo cracking to form products in the range of diesel or gasoline, and linear paraffins can be isomerized to improve the properties of the diesel product such as the point of cloudiness and pour point. Generally used hydrotreatment catalysts adapted for this third stage.

US 5,928,980 discloses the use (in the second stage of the Fischer-Tropsch process) of a spent fluid catalytic cracking catalyst (FCC) impregnated with a group VIII metal, preferably cobalt and / or iron This catalyst composition is prepared by impregnating the spent FCC catalyst with a metal salt, calcining the impregnated FCC catalyst to obtain a supported metal oxide and reducing the metal oxide to give the metal in a reducing gas atmosphere. The impregnated metal serves as a Fischer-Tropsch catalyst.

The preparation of this composition of prior art catalyst requires a procedure cumbersome (which involves the stages of impregnation, calcination and reduction). It is therefore an object of the present invention provide a procedure for the conversion of monoxide from carbon and hydrogen in mixtures of C5 + hydrocarbons using a catalyst system of Fischer-Tropsch and an FCC catalyst, a system that  It is easier to prepare.

A second object is to provide a procedure using a catalyst system that can be used in  a more flexible way as needed.

A third object is to provide a system of economic catalyst

The prior art only discloses the use of FCC catalyst spent on a process of Fischer-Tropsch It is a fourth object of the present invention expand the scope of the FCC catalyst to be used in Fischer-Tropsch procedures using also other types of FCC catalysts. The document US-A-4 906 671 describes a procedure to produce diesel from hydrogen and oxides of carbon using a catalyst system comprising a FCC catalyst and an FT catalyst.

Document US3254023, example 6 deals with a procedure in which a type synthesis is used Fischer-Tropsch as an addition reaction exothermic, serving the heat derived from it to effect an endothermic dehydration reaction. It is a dehydration of isobutanol to give isobutylene catalyzed by a zeolite and synthetic. The reactions are carried out under pressure atmospheric

According to the invention a method according to claim 1.

The method according to the invention uses Fischer-Tropsch catalyst particles and fluid catalytic cracking catalyst particles. So, The catalyst composition according to the present invention can be prepared simply by mixing catalyst particles of Fischer-Tropsch and FCC catalyst particles existing. Its preparation does not require impregnation stages. desired from an industrial point of view.

In one embodiment, the particles of Fischer-Tropsch catalyst and particles of FCC catalyst can be used in the form of bodies formed in which both particles are embedded. Examples of bodies shaped are spray dried particles (microspheres), extrudates, granules, spheres, etc.

Such shaped bodies can be prepared forming a physical mixture of catalyst particles of Fischer-Tropsch and FCC catalyst particles. Suitable methods to obtain such shaped bodies include spray drying, granulation, extrusion (optionally combined with kneading), pearl formation or any other conventional conformation method used in fields of catalysts and absorbents or combinations of same. For example, if the preparation of the particles of Fischer-Tropsch catalyst involves a stage of spray drying, it is possible to add the FCC catalyst to the Fischer-Tropsch catalyst before drying by spraying and subsequently spray drying the resulting mixture.

If desired, a bonding material can be added or matrix to improve the mechanical resistance of the bodies conformed Examples of suitable bonding or matrix materials are alumina, silica, clays and mixtures thereof. Generally they prefer bonding materials or matrix comprising alumina. The bonding material or matrix, if present, is present preferably in an amount of 10-40% by weight, more preferably 15-35% by weight, and most preferably 25-35% by weight, based on the Total weight of the catalyst composition.

The term "FCC catalyst" includes new FCC catalysts, spent FCC catalysts and equilibrium catalysts (E-cat, equilibrium catalysts ). A spent FCC catalyst is less expensive than a new FCC catalyst. In addition, its use results in the reuse of waste materials, which is economically and environmentally favorable.

If the FCC catalyst particles and the Fischer-Tropsch catalyst particles no they are in the form of shaped bodies in which both particles are embedded, the catalyst particles of Fischer-Tropsch and catalyst particles of FCC can be dosed individually (as needed) at Fischer-Tropsch unit. This creates a great flexibility. For example, if the procedural conditions change during processing or if one of the catalysts is deactivates faster than the other, one of the catalysts can be added with a faster dosing rate than the other.

In addition, the quality of the E-cat or The spent FCC catalyst will vary from batch to batch. This difference can be compensated by adapting the dosing rate of the FCC catalyst particles compared to that of Fischer-Tropsch catalyst particles. In addition, it is possible either to use both types of particles of catalyst in the second stage of the process of Fischer-Tropsch, or use the particles of Fischer-Tropsch catalyst in the second stage and FCC catalyst particles in the third stage.

In the process according to the invention FCC catalysts containing zeolite Y are used. Such FCC catalysts generally contain zeolite Y, clay (for example kaolin, metacaolin, bentonite), silica, alumina, rare earth metal compounds, etc. Examples of suitable metals are rare earth metals, for example Ce, La, and transition metals of groups IV-VIII of the Periodic System, for example V, Cr, Mn, Fe, Co, Ni, Cu, Zr, Nb, Ru, Re, etc. The metal compounds can serve, for example, to increase the resistance of the particles (for example compounds of La), enhance the stability of the catalyst (for example compounds of Ni) or enhance the conversion of CO (for example compounds of Fe, Co or Ru). This metal compound is preferably present in or on the FCC catalyst particles in amounts of 0.1 to 10% by weight, more preferably 0.3 to 2% by weight, calculated as oxide and based on the total weight of FCC catalyst that contains
metal.

The metal compound can be deposited on FCC catalyst particles in any known manner in the technique Examples of such methods are impregnation, ion exchange and precipitation by deposition of salts of soluble metals

If desired, the catalyst particles of FCC with deposited metal are calcined and / or previously reduced after the metal compound has been deposited.

An additional advantage of using a catalyst FCC spent compared to a new FCC catalyst is that A spent FCC catalyst will generally contain a compound of desired metal, due to the fact that the feeding of hydrocarbons to be subjected to cracking in an FCC unit It usually contains various metals (for example nickel, vanadium). Therefore, no stage of additional deposition to introduce a metal compound of this kind.

The catalyst of Fischer-Tropsch can be any catalyst of Conventional Fischer-Tropsch, which preferably It comprises iron and / or cobalt. For the preparation of such Catalysts are referred, for example, to WO documents 01/97968, WO 01/89686 and WO 01/70394.

The catalyst of Fischer-Tropsch can be promoted with various metals, for example Al, Ti, Cr, Mn, Ca, Na and / or K. In addition, the Fischer-Tropsch catalyst particles can contain binder materials, such as silica and / or alumina.

Both the FCC catalyst particles and Fischer-Tropsch catalyst particles can be used in the second stage of the procedure of Fischer-Tropsch, or in the form of particles separated, or in the form of shaped bodies in which both particles are embedded. Based on the total weight of FCC catalyst particles and catalyst particles of Fischer-Tropsch, the catalyst particles of FCC are preferably used in an amount of 5 to 40% by weight, more preferably from 10 to 30% by weight.

The second stage can be carried out in any suitable reactor, such as a fluidized bed reactor (permanent). The temperature preferably ranges from 250 ° to 400 ° C, more preferably from 300 ° to 370 ° C, and most preferably from 330 ° to 350 ° C. The pressure ranges from 10 up to 60 bar, more preferably 15 to 30 bar, and most preferably in about 20 bar.

The volume ratio of H2 / CO oscillates preferably from 0.2 to 6.0, preferably 0.5-6, most preferably 1-3.

The third stage is usually performed at temperatures of 150 to 600 ° C, more preferably 200 to 500 ° C, and most preferably from 300 to 400 ° C. Pressure ranges preferably from 5 to 60 bar, more preferably from 15 up to 40 bar, and most preferably from 20 to 30 bar.

The resulting hydrocarbon product contains preferably, based on mass, at least 35%, more preferably at least 45%, and most preferably at least 50% of C5 + compounds. The procedure can be used. for the production of aromatic compounds, olefins and / or branched hydrocarbons. Preferably, the procedure is used. for the production of liquid fuel, especially diesel and gasoline, and preferably unleaded gasoline.

Example

The following experiments illustrate the suitability of FCC catalysts based on zeolite Y (new and E-cat), for the isomerization of products linear olefins under typical conditions of the Fischer-Tropsch Catalysts that are suitable for this purpose or in the second stage (as cocatalyst) or in the third stage of the procedure Fischer-Tropsch in order to enhance the Isomerization of linear olefinic products.

For this purpose the performance was tested of the FCC catalysts in a hydroisomerization of 1-hexene The reaction conditions (temperature, total pressure and dihydrogen pressure) for testing performance were identical to the conditions present in a typical Fischer-Tropsch procedure at high temperature:

Temperature

: 340 ° C

Total pressure

: 20 bar

Entrance of catalyst

: 2.2 g

WHSV, 1-Hexene

: 2.85 g / g / h

quad

{} \ hskip0.1cm (based on zeolite Present)

Partial pressure of H2

: 9 bar

Partial pressure of N_ {2}

: 10.8 bar

Partial pressure of 1-hexene

: 0.22 Pub

Molar ratio of H 2/1-hexene

: 40.9

Molar ratio of N2 / 1-hexene

: 49.1

FCC catalysts in situ in the reactor were reduced to a hydrogen pressure of 20 bar at 340 ° C for 1 h. Once the reduction procedure was completed, the nitrogen flow was introduced and subsequently 1-hexene (0.11 ml / min) was dosed. The composition of the reaction product was monitored by an online GC analysis.

Three different types of FCC catalysts by this process were tested: a catalyst again FCC containing a low amount of rare earth (RE, rare earth) catalyst new FCC containing a high amount of rare earth metals , and an equilibrium FCC catalyst (E-cat) that resulted from the FCC catalyst with a low amount of RE. The product distributions obtained in these tests at an execution time of 0.5 h and 17.5 h are presented in tables 1 and 2, respectively.

In these tables, n -C6 refers to normal C6 paraffins, and -C6 refers to branched C6 paraffins, n -C6 = refers to olefins Normal C 6, i-C 6 = refers to branched C 6 olefins, and <C 6 and> C 6 refers to compounds with less and more than 6 carbon atoms respectively.

TABLE 1 Test results at a runtime of 0.5 h

one

TABLE 2 Test results at a runtime of 17.5 h

2

As can be seen from these tables, the new FCC catalyst with a low amount of RE it has a high selectivity for branched C6 olefins (i-C6 =) and branched C6 paraffins (i-C_ {6}). Total quantities of products isomerized at an execution time of 0.5 h and 17.5 h were 52.0% by weight and 60.1% by weight, respectively. She's tall isomerization selectivity was accompanied by a low level of cracking only 3.4% by weight of products smaller than C_ {6} (<C_ {6}) at a runtime of 17.5 h. The quantity of aromatic products was well below 1% in weight throughout the execution.

The new FCC catalyst with a high amount of RE also showed high selectivity for C6 branched olefins (i-C6 =) and the C6 branched paraffins (i-C6). The total quantities of isomerized products at a time of execution of 0.5 h and 17.5 h were 44.8% by weight and 60.5% in weight, respectively. The level of cracking was 5.3% by weight at a runtime of 17.5 h. The amount of aromatic products It was well below 1% by weight throughout the execution.

The equilibrium FCC catalyst showed a somewhat lower selectivity with respect to C6 olefins branched (i-C6 =) and C6 paraffins branched (i-C6) than FCC catalysts new. Total quantities of products isomerized to a runtime of 0.5 h and 17.5 h were 38.2% by weight and the 39.8% by weight, respectively. The level of cracking was only 3.0% by weight at an execution time of 17.5 h. Again the quantity of aromatic products was well below 1% in weight throughout the execution. Although the level of isomerization of this E-cat was inferior to that of the catalysts of New FCC is still acceptable for use in the product of Fischer-Tropsch, especially as a cocatalyst In the second stage.

These experiments show that FCC catalysts can isomerize olefinic hydrocarbons linear in typical Fischer-Tropsch conditions. This indicates its suitability for use in the second and third Fischer-Tropsch procedure stage.

Claims (11)

1. Procedure of Fischer-Tropsch for the conversion of monoxide from carbon and hydrogen in mixtures of C 5 + hydrocarbons, procedure in which catalyst particles are used Fischer-Tropsch and catalyst particles fluid catalytic cracking containing zeolite Y, comprising said process contacting carbon monoxide and the hydrogen with catalyst particles of Fischer-Tropsch at a pressure in the range of from 10 to 60 bar leading to hydrocarbons and water, and isomerize the hydrocarbons with the catalyst particles of fluid catalytic cracking. 2. Method according to claim 1, in which the mixture of carbon monoxide and hydrogen is put in contact with a mixture of catalyst particles of Fischer-Tropsch and catalyst particles fluid catalytic cracking, in which the catalyst particles of fluid catalytic cracking comprise from 5 to 40% in weight of said mixture. 3. Method according to claim 2, in which the catalyst particles of Fischer-Tropsch and catalyst particles of fluid catalytic cracking is dosed individually to the mixture of reaction. 4. Method according to claim 2, in which the catalyst particles of Fischer-Tropsch and catalyst particles of fluid catalytic cracking are used in the form of bodies formed in those that are embedded both particles. 5. Method according to claim 1, in which the step of contacting catalyst particles of Fischer-Tropsch with a mixture of monoxide carbon and hydrogen to form a hydrocarbon mixture C_ {5} + is followed by a separate step of contacting the mixture of C 5 + hydrocarbons with the particles of fluid catalytic cracking catalyst. 6. Procedure according to any one of the previous claims, wherein the catalyst particles  of Fischer-Tropsch comprise iron. 7. Procedure according to any one of the previous claims, wherein the catalyst particles  of Fischer-Tropsch comprise cobalt. 8. Procedure according to any one of the previous claims, wherein the cracking catalyst fluid catalytic is a fluid catalytic cracking catalyst in balance or spent. 9. Procedure according to any one of the previous claims, in which a compound has been deposited  metal on catalytic cracking catalyst particles fluid. 10. Method according to claim 1, which understands: a first stage that involves reacting a carbon source with an oxygen source to form a mixture of carbon monoxide and hydrogen; a second stage where they get in touch carbon monoxide and hydrogen with particles of Fischer-Tropsch catalyst leading to hydrocarbons and water; Y a third stage in which the hydrocarbons formed in the second stage; in which cracking catalyst particles Catalytic fluid containing zeolite Y are used in the third stage. 11. Procedure according to any one of the previous claims, wherein the catalyst particles  Catalytic cracking fluid isomerize olefinic hydrocarbons linear