RU2227067C1 - Method of production of catalyst and a method of production of hydrocarbons and their oxygen-containing derivatives with the catalyst use - Google Patents

Abstract

FIELD: chemical and petrochemical industries. SUBSTANCE: the invention presents a method of preparation of a catalyst and a method of production of hydrocarbons and their oxygen-containing derivatives with the catalyst use. The invention is pertinent to the catalysts used for production of hydrocarbons, including liquid synthetic fuels, olefins, solid hydrocarbons as well as their oxygen-containing derivatives, for example - alcohols from a mixture of CO and hydrogen. The invention solves a problem of development of a method of an efficient catalyst production and a method of production of hydrocarbons and their oxygen-containing derivatives with use of this catalyst. The catalyst is prepared from powders of a catalytically active agent, a heat- conducting agent and a cellulating agent with the particles sizes of less than 300 microns in the following way: powders of the heat- conducting and the cellulating agents are mixed, the produced powder is further mix with the catalytically active agent, the obtained mixture is compressed and a body of the catalyst is given the necessary shape. Then the body of the catalyst is subjected to a high-heat treatment. EFFECT: the invention allows to obtain the method of efficient catalyst for production of hydrocarbons and their oxygen-containing derivatives. 15 cl, 2 tbl l, 10 ex

Description

The invention relates to catalysts for the production of hydrocarbons, including liquid synthetic fuels, olefins, solid hydrocarbons, as well as their oxygen-containing derivatives, for example alcohols from a mixture of CO and hydrogen (synthesis gas). Subsequently, the resulting hydrocarbons can be used to generate energy (i.e., to burn as fuel) or to obtain useful chemical compounds, for example, hydrocarbons with fewer carbon atoms per molecule, polymeric materials, higher alcohols, surfactants, and other

Known methods for converting synthesis gas into valuable chemical products by reactions

nCO + (2n + 1) H ₂ = C _n H _{2n + 2} + nH ₂ O

nCO + (2n) H ₂ = C _n H _2n + nH ₂ O

nCO + (2n) H ₂ = C _n H _{2n + 1} OH + (n-1) H ₂ O

in the presence of a catalyst. These methods are combined under the name "Fischer-Tropsch synthesis." As a result of the Fischer-Tropsch synthesis, saturated and unsaturated hydrocarbons with any number of carbon atoms from 1 (methane) to more than 100, as well as alcohols, can be quantified and isolated. The catalyst usually contains one or more elements from the group: iron, cobalt, nickel, ruthenium. The synthesis gas may have a different ratio of CO: H ₂ content, determined by the method of its production, and may also be diluted with nitrogen.

An analysis of the characteristic features of the Fischer-Tropsch synthesis carried out in a review by A.A. Khasin, V.A. Kirillov, Catalysis in Industry, No. 2, 2002, pp. 26-37, made it possible to formulate the basic requirements for the organization of the catalytic layer for the Fischer-Tropsch synthesis process. As a result of the analysis, the following criteria to the catalyst bed are formulated, which are necessary to ensure the efficient implementation of the Fischer-Tropsch synthesis process:

1. a high concentration of catalytically active component in the reaction volume;

2. small characteristic particle size of the catalyst (less than 50 microns);

3. high effective thermal conductivity of the catalyst layer;

4. Developed gas-liquid phase interface;

5. Providing a convective gas flow regime close to the ideal displacement regime.

The cited review also concludes that the process schemes with conventional catalysts in the suspended layer, fixed bed, or fluidized bed do not meet the requirements. Therefore, increasing the efficiency of the process for producing hydrocarbons from synthesis gas requires the development of a new method for preparing a catalyst.

Closest to the above problems is solved by the invention of US Patent 5716899, B 01 J 21/04, 02/10/1998. This invention provides a method of preparing a catalyst body by placing a suspension containing particles of a catalytically active agent and other materials, including ceramics, metals, glass, etc., in a matrix of a cellular material having parallel channels separated by walls whose porosity exceeds 45%. During subsequent drying, the liquid is removed from the suspension. In this case, it is preferable to use a ceramic cellular matrix, since this provides a high porosity of the matrix walls.

The disadvantage of the proposed method is the low content of the catalytically active component per unit volume of the catalyst body, as well as the difficulty of achieving a wall thickness of less than 50 μm, which is necessary to ensure intensive mass transfer within the porous structure of the matrix wall. It should also be noted the low thermal conductivity of ceramic materials, proposed by the invention as a matrix.

The problem solved by this invention is to develop a method for preparing an effective catalyst for the production of hydrocarbons and their oxygen-containing derivatives from synthesis gas, which meets the following requirements:

1. A high concentration of catalytically active agent is not less than 0.4 g / cm ³ ;

2. High mechanical strength of the catalyst body;

3. High thermal conductivity of the catalyst body - at least 1 W / (m · K);

4. High gas permeability of the catalyst body - not less than 5 · 10 ^-15 m ² ;

5. Developed porous structure with a predominance of pores smaller than 50 microns.

In the present invention, a catalyst for converting synthesis gas to hydrocarbons is prepared by sequentially carrying out the following operations:

- the preparation of powders A, B and C, respectively, consisting of granules of a catalytically active agent (powder A), a heat-conducting agent (powder B) and a pore-forming agent (powder C) with a size of less than 300 microns,

- a mixture of powders B and C (powder D),

- compaction of powder G, preparation of a fraction of less than 300 microns from a compacted mass of powder,

- mixing of powders A and G,

- compaction of the mixture and giving the body of the catalyst the necessary shape,

- heat treatment of the catalyst body.

The term “catalytically active agent” is understood here to mean a set of phases including a phase containing cations of an active metal (for example, cobalt, iron, nickel, ruthenium or with their content). Essentially important is the ability of the catalytically active agent to transform during the heat treatment of the catalyst body in a reducing medium into a set of phases, including the active metal phase, fixed on the phase of the substrate of an oxide nature, which has a decisive influence on the physicochemical properties of the active metal phase, for example, its dispersion. Moreover, the content of the active metal in the said set of phases should be more than 5 wt.%, Preferably 8-30 wt.%. The catalytically active agent can be prepared according to one of the previously described cooking methods by precipitation (US Patent 5397806, C 07 C 001/04, 03/14/95), impregnation (US Patent 4960801, C 07 C 001/04, 02.10.90, US Patent 4613624, C 07 C 001/04, 09/23/86) or in another known or original way. Preferably, the phase of the active metal formed during the heat treatment has a predominant particle size of from 6-7 to 9-11 nm.

By the term “heat-conducting agent” is meant a phase or a combination of phases of one or more metals inert with respect to synthesis gas, for example copper, zinc, aluminum or their intermetallic compounds and alloys. Essentially important properties for a heat-conducting agent are its high thermal conductivity after the heat treatment stage (at least 50 W · m ^-1 · K ^-1 ) and stability under reaction conditions. An important property is the possibility of forming reliable contact between the granules of the heat-conducting agent at the stage of heat treatment. For this, it is necessary that the Tamman temperatures for the phases of the heat-conducting agent do not exceed the temperature of the heat treatment stage. It should be noted that the heat-conducting agent in the catalyst also functions as a hardening (reinforcing) agent.

By the term “pore-forming agent” is meant a phase or set of phases that decompose during heat treatment to gaseous chemical compounds or to gaseous chemical compounds with the formation of solid phases simultaneously, the volume of which is substantially less than the volume of the initial pore-forming agent. As a pore-forming agent, it is preferable to use salts and / or oxides and / or hydroxides and / or hydroxocarbonates of one or more metals included in the heat-conducting agent (for example, basic copper carbonate (malachite) when using metallic copper as a heat-conducting agent) . A catalytically active agent can also be used as a pore-forming agent if its transformations during heat treatment are accompanied by a significant decrease in the volume of the solid phase.

To ensure the necessary parameters of the porous structure of the catalyst body, the granules constituting the powders A, B, C and D should have a size of less than 300 microns (preferably less than 200 microns). It is preferable that the prevailing particle sizes in the mixed powders are close.

The ratios of the content of the heat-conducting agent, the content of the pore-forming agent and the content of the catalytically active agent are determined by the optimal ratio of the strength – gas permeability – productivity parameters and can vary over a wide range. At the same time, to ensure the necessary catalyst parameters, it is necessary to observe the ratio of the mass content of powder B to the mass content of powder B not more than 4, and the mass ratio of the content of powder A to the mass content of powder G not less than 0.25.

It should be noted that the stage of compaction of the powder G is optional, although its introduction into the proposed method increases the strength characteristics of the catalyst and the efficiency of the Fischer-Tropsch synthesis process using it.

Compaction of the powder mixture A and D and shaping of the catalyst body can be carried out using any of the known tabletting, extrusion or rolling methods on a rolling mill, preferably at a compaction pressure of more than 2000 kgf / cm ² . The geometric shape of the body of the concentrated permeable catalyst can be any and is determined by the requirements for a particular reactor. Most preferred are the shapes of plates (including disks) and hollow cylinders with cross-sections of various geometry (including hollow cylinders of revolution). The thickness of the plate (or cylinder wall) can be from fractions of a millimeter to 1 m; the optimal size is determined from the technological parameters of the cooking method and the conditions for achieving a reasonable pressure drop across the catalyst body.

The heat treatment of the catalyst body can be carried out in one or two stages. In this case, it is essential that the final heat treatment be carried out in a stream of hydrogen or a hydrogen-containing gas. The heat treatment temperature should be higher than the Tamman temperature (i.e., about 0.5 of the absolute melting temperature) of at least one of the phases that make up the heat-conducting agent, on the one hand, and ensure optimal recovery of active metal cations from the structure of the catalytically active agent, on the other side.

The main advantages of the proposed method for the preparation of the catalyst are the high content of the catalytically active agent per unit volume of the catalyst body while ensuring the developed porous structure of the catalyst body, as well as the high thermal conductivity of the resulting catalysts, which allows to reduce the temperature gradient inside the catalyst body, that is, to ensure the flow of the exothermic process in the mode close to isothermal. An additional advantage of the proposed method is the simplicity of separation of the reaction products from the solid phase, which is provided by the relatively large overall dimensions of the catalyst body and its high mechanical strength. The heat removal from the bodies of the concentrated permeable catalyst can be provided by thermal contact of the catalyst bodies with the wall of the reactor or with the wall of additional heat exchangers introduced into the reaction volume.

The problem is also solved by a method for producing hydrocarbons and / or their oxygen-containing derivatives from synthesis gas using a catalyst prepared as described above.

The invention is illustrated by the following examples.

Example 1. The catalyst is prepared on the basis of the following powders:

Powder A — Co-Al hydroxocarbonate powder (1: 1) with a hydrotalcite structure, prepared according to the procedure described in A.A. Khassin, T.M. Yurieva, G.N. Kustova, I.Sh. Itenberg, M.P. Demeshkina, T.A. Kriger, L.M. Plyasova, G.K. Chermashentseva and V.N. Parmon. Cobalt-aluminum co-precipitated catalysts and their performance in the Fischer-Tropsch synthesis. J. Mol. Catal. A: Chem., 168 (1-2), 193-207 (2001). This hydroxocarbonate has the ability to transform during the reduction treatment in a stream of hydrogen into a combination of phases of the active metal (cobalt) and the anion-modified co-oxide Co-Al. According to titration of the amount of active metal (cobalt) with atmospheric oxygen (control was carried out by weight change), according to photoelectron spectroscopy, and also according to magnetic susceptibility, the content of the active metal in the mentioned set of phases is about 27 wt.% [A.A. Khassin, V.F. Anufrienko, V.N. Ikorskii, L.M. Plyasova, G.N. Kustova, T.V. Larina, I.Yu. Molina and V.N. Parmon. Phys. Chem. Chem. Phys., 4 (17), 4236-4243 (2002).] The grains forming the powder have a size of less than 250 microns.

Powder B is a copper metal powder with a particle size of less than 50 microns.

Powder B is a powder of basic copper carbonate Cu ₂ (OH) ₂ CO ₃ (malachite).

The mixture of powders B and C to obtain powder D is carried out in a ratio of 3: 2 wt. share. The powder compaction G is carried out by tabletting at a pressure of 4000 kgf / cm ² , then crushing is carried out and a fraction of particles with a size of less than 250 microns is sifted out.

The mixing of powders A and G is carried out in a ratio of 9:11 wt. Compaction of the mixture A and G and shaping the disk with a diameter of 15 mm and a height of 6 mm is carried out by tabletting at a pressure of 3000 kgf / cm ² .

Heat treatment is carried out in two stages - in an argon stream at a temperature of 550 ° C and in a stream of hydrogen at a temperature of 650 ° C. After heat treatment, the catalyst body has the following phase composition: metallic copper + metallic cobalt, mounted on the surface of anionically modified cobalt aluminate.

The main parameters of the obtained catalyst are shown in Table 1.

Catalytic tests are carried out in a flow reactor with the composition of the reaction mixture CO 30 vol.%, N ₂ 60 vol.%, N ₂ 10 vol.%, At a pressure of 0.1 MPa and a temperature of 210 ° C. The flow of the reaction mixture is passed through the catalyst body through the transport pores. The flow around the catalyst body is eliminated by sealing the side surfaces of the disk. The catalytic properties of the obtained catalyst are shown in Table 2.

Example 2. The catalyst is prepared analogously to example 1, but a powder of Co-Zn-Al hydroxocarbonate with a hydrotalcite structure prepared according to the procedure described by A.A. is used as powder A. Khassin, T.M. Yurieva, G.N. Kustova, I.Sh. Itenberg, M.P. Demeshkina, T.A. Kriger, L.M. Plyasova, G.K. Chermashentseva and V.N. Parmon. Cobalt-aluminum co-precipitated catalysts and their performance in the Fischer-Tropsch synthesis. J. Mol. Catal. A: Chem., 168 (1-2), 193-207 (2001), with a particle size of less than 150 microns. This hydroxocarbonate has the ability to transform during processing in a stream of hydrogen into a set of phases of the active metal (cobalt) and anion-modified joint oxide Zn-Al. According to titration of the amount of active metal (cobalt) with atmospheric oxygen (control was carried out by weight change), the content of the active metal in the mentioned set of phases is about 24 wt.%. Powder G also contains particles less than 150 microns in size. After heat treatment, the catalyst body has the following phase composition: metallic copper + metallic cobalt, mounted on the surface of anionically modified zinc aluminate.

The main parameters of the obtained catalyst are shown in Table 1.

The catalytic properties of the obtained catalyst are shown in Table 2.

Example 3. The catalyst is prepared analogously to example 1, but as a powder And use a joint hydroxocarbonate Ni-Mg (1: 1), prepared by the coprecipitation of cations of nickel and magnesium from solutions of nickel and magnesium nitrates with a solution of NaOH at 60 ° C, pH 10.5 . This hydroxocarbonate has the ability to transform during processing in a stream of hydrogen into a set of phases of an active metal (nickel) and a joint oxide of Ni-Mg. According to titration of the amount of active metal (nickel) with atmospheric oxygen (control was carried out by weight change), the content of the active metal in the mentioned set of phases is about 32 wt.%. The grains forming the powder have a size of less than 150 microns.

The obtained fractions of powder A and powder G are mixed in a ratio of 2: 3 wt.

Compaction of the mixture of powders A and G and shaping a round plate with a diameter of 15 mm and a height of 6 mm is carried out by tabletting at a pressure of 3000 kgf / cm ² .

Heat treatment is carried out in one stage - in a stream of hydrogen at a temperature of 650 ° C. After heat treatment, the catalyst body has the following phase composition: metallic copper + metallic nickel, mounted on the surface of the joint nickel-magnesium oxide.

The main parameters of the obtained catalyst are shown in Table 1.

The catalytic properties of the obtained catalyst are shown in Table 2.

Example 4. The catalyst is prepared analogously to example 1, but as the powder B, tin bronze powder of the PbrO10 grade (Cu 90 at.%, Sn 10 at.%) With a particle size of less than 70 microns is used. The mixture of powders B and C to obtain powder D is carried out in a ratio of 4: 3 wt. share. The obtained fractions of powder A and powder G are mixed in a ratio of 1: 1 wt.

After heat treatment, the catalyst body has the following phase composition: an alloy of copper with tin + metallic copper + metallic cobalt, mounted on the surface of anion-modified cobalt aluminate.

The main parameters of the obtained catalyst are shown in Table 1.

The catalytic properties of the obtained catalyst are shown in Table 2.

Example 5. The catalyst is prepared analogously to example 1, but the powder of powder B is a powder of copper hydroxide Cu (OH) ₂ with a particle size of less than 50 microns.

The mixture of powders B and C to obtain powder D is carried out in a ratio of 3: 2 wt. share. The obtained fractions of powder A and powder G are mixed in a ratio of 1: 1 wt.

After heat treatment, the catalyst body has the following phase composition: metallic copper + metallic cobalt, mounted on the surface of anionically modified cobalt aluminate.

The main parameters of the obtained catalyst are shown in Table 1.

The catalytic properties of the obtained catalyst are shown in Table 2.

Example 6. The catalyst is prepared analogously to example 1, but as a pore-forming agent, powder B, a catalytically active agent is used — a Co-Zn-Al hydroxocarbonate powder with a hydrotalcite structure. The compaction of powder A is carried out by tabletting at a pressure of 4000 kgf / cm ² , then crushing is carried out to obtain a powder with a fraction of less than 250 microns. The stage of mixing the pore-forming agent and the heat-conducting agent is not carried out. The obtained fractions of powder A, powder B and powder C are mixed in a ratio of 9:16 wt.

Compaction of the mixture of powders A and B and shaping a round plate with a diameter of 15 mm and a height of 6 mm is carried out by tabletting at a pressure of 3000 kgf / cm ² .

After heat treatment, the catalyst body has the following phase composition: metallic copper + metallic cobalt, mounted on the surface of anionically modified cobalt aluminate.

The main parameters of the obtained catalyst are shown in Table 1.

The catalytic properties of the obtained catalyst are shown in Table 2.

Example 7. The catalyst is prepared analogously to example 1, but the mixing of powders B and C to obtain a powder G is carried out in a ratio of 2: 1 wt.%, And the mixing of powders A and G is carried out in a ratio of 2: 3 wt.

After heat treatment, the catalyst body has the following phase composition: metallic copper + metallic cobalt, mounted on the surface of anionically modified cobalt aluminate.

The main parameters of the obtained catalyst are shown in Table 1.

The catalytic properties of the obtained catalyst are shown in Table 2.

Example 8. The catalyst is prepared analogously to example 1, but the mixing of powders A and G is carried out in a ratio of 1: 2 wt.%.

The main parameters of the obtained catalyst are shown in Table 1.

The catalytic properties of the obtained catalyst are shown in Table 2.

Example 9. The catalyst is prepared analogously to example 2, but the body shape of the concentrated permeable catalyst is a hollow rotation cylinder with an external diameter of 45 mm, an internal diameter of 10 mm and a height of 30 mm, and the mixture of A and D is compressed and shaped into a hollow rotation cylinder by tabletting at a pressure of 2300 kgf / cm ² .

The main parameters of the obtained catalyst are shown in Table 1.

The catalytic properties of the obtained catalyst are shown in Table 2.

Example 10. The catalyst is prepared analogously to example 1, but the body shape of the concentrated permeable catalyst is a 1 mm thick plate, and the compaction and shaping of the body of the concentrated permeable catalyst is carried out by rolling a mixture of powders A and G on rollers with a diameter of 35 cm with an estimated seal pressure of about 3500 kgf / cm ² .

The main parameters of the obtained catalyst are shown in Table 1.

Claims (15)

1. A method of preparing a catalyst for producing hydrocarbons and / or their oxygen-containing derivatives from synthesis gas, characterized in that the catalyst is prepared from powders of a catalytically active agent, a heat-conducting agent and a pore-forming agent with a particle size of less than 300 μm as follows: powders of a heat-conducting and pore-forming agents are mixed , the obtained powder is further mixed with a catalytically active agent, the resulting mixture is compacted and the necessary shape is given to the catalyst body, then thermal is carried out processing of the catalyst body. 2. The method according to claim 1, characterized in that after the stage of mixing the powders of the heat-conducting and pore-forming agents, the obtained powder is densified and a powder is prepared from the compacted mass, consisting of granules with a size of less than 300 microns. 3. The method according to any one of claims 1 and 2, characterized in that the ratio of the mass content of the pore-forming agent to the mass content of the heat-conducting agent does not exceed 4. 4. The method according to any one of claims 1 to 3, characterized in that the ratio of the mass content of the catalytically active agent to the mass content of the heat-conducting and pore-forming agents is not less than 0.25. 5. The method according to any one of claims 1 to 4, characterized in that the catalytically active agent contains one of the metals of group VIII. 6. The method according to any one of claims 1 to 5, characterized in that the phase content of the catalytically active metal in the catalytically active agent is at least 2 wt.%. 7. The method according to any one of claims 1 to 6, characterized in that metal copper and / or zinc and / or aluminum and / or tin and / or mixtures thereof or alloys are used as the heat-conducting agent. 8. The method according to any one of claims 1 to 7, characterized in that the oxide and / or hydroxide and / or carbonate and / or hydroxocarbonate and / or the salt of one or more metals included in the composition are used as a pore-forming agent. heat transfer agent. 9. The method according to any one of claims 1, 3-7, characterized in that the powder of a catalytically active agent is used as a pore-forming agent. 10. The method according to any one of claims 1 to 9, characterized in that the compaction of the mixture and shaping the body of the catalyst is carried out by tabletting. 11. The method according to any one of claims 1 to 9, characterized in that the compaction of the mixture and shaping the body of the catalyst is carried out by rolling the mixture in a rolling mill with the introduction of an additional stage of cutting the plate of the desired shape. 12. The method according to any one of claims 1 to 11, characterized in that the catalyst body is shaped into a cylinder, or a perforated cylinder, or a plate, or a profiled plate. 13. The method according to any one of claims 1 to 12, characterized in that the heat treatment is carried out in a stream of hydrogen-containing gas at a temperature above 400 ° C. 14. The method according to any one of claims 1 to 12, characterized in that the heat treatment is carried out in two stages in a stream of inert gas at a temperature above 400 ° C and in a stream of hydrogen-containing gas at a temperature above 300 ° C. 15. A method of producing hydrocarbons and / or their oxygen-containing derivatives from synthesis gas, characterized in that it is carried out using a catalyst prepared according to any one of claims 1 to 14.