High-temperature-resistant coal catalytic gasification catalyst and preparation method thereof

Abstract

The application provides a high-temperature-resistant coal catalytic gasification catalyst and a preparation method thereof, and relates to the field of catalysts; the method comprises the following steps: performing pyrolysis treatment on coal bases to obtain semicoke, immersing the semicoke in an organic metal salt of an alkali metal to form a catalyst precursor, adding a modifier to the catalyst precursor to perform modification treatment, and adopting an ion exchange method to composite active components to the modified catalyst precursor to prepare a composite catalyst. The catalyst prepared by the application has a conversion rate of 89.1% and a cumulative methane generation amount of 12.9 mmol.g ‑1 -1.min-1 after 300 min of reaction, and the content of methane in the product reaches 26.4%, which shows excellent methane production performance.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of catalysts, in particular to a high-temperature-resistant coal catalytic gasification catalyst and a preparation method thereof. BACKGROUND

[0002] Coal catalytic gasification technology was first developed in 1976, during which Exxon Corporation and Giant Point Energy Corporation in the United States proposed coal catalytic gasification schemes; in China, Xinao successfully developed a complete coal catalytic gasification process system after years of exploration, and the technology reached an international leading level, and industrialized production began in 2017.

[0003] The prior art has reported a large number of schemes for realizing coal catalytic gasification by using sodium carbonate as a catalyst, and carbonates of potassium and sodium, salts of alkaline earth metals and transition metals are good catalysts for coal catalytic gasification. Coal catalytic gasification is a typical gas-solid heterogeneous reaction, and the gas-phase reactants react with carbon on the surface of coal loaded with a catalyst, and the activity of the catalyst depends on the specific surface area of coal and its dispersion degree on the surface of coal. In addition to the active center of the surface oxide group formed by alkali metals and carbon on the surface of sodium / potassium carbonate, sodium / potassium carbonate also changes the pore structure of the coal surface, and further melting and diffusion at the gasification temperature can improve the activity of the coal. For example, Exxon Mobil Corporation used K2CO3 as a catalyst and developed a coal pressurized fluidized bed catalytic gasification process for the purpose of producing substitute natural gas. After adding the K2CO3 catalyst, the carbon conversion rate was greatly improved, and the reaction rate was about 4 times higher in the same reaction time.

[0004] Compared with single-component catalysts, multi-component catalysts with higher gasification efficiency have been widely concerned in recent years. For example, a mixture of K2SO4 and FeSO4 was used as a catalyst for gasification of Pittsburgh HVA coal, and the reaction conditions were as follows: the molar ratio of K / Fe was 9, the temperature was 850℃, the pressure was 0.1 MPa, the atomic ratio of metal / carbon was 0.02, the metal loading was 5.1-7.3 g / 100 g carbon, the carbon particle size was 53-106 μm, and the reaction gas was H2O / H2 or H2O / N2 (the H2O content was 30%). Under the above conditions, the carbon conversion rate reached 100%, while the carbon conversion rate was only 89% when K2CO3 was used as a catalyst alone. For another example, a ternary catalyst Li2CO3-Na2CO3-K2CO3, a binary catalyst Na2CO3-K2CO3, and a single-component catalyst K2CO3 were used for coal gasification kinetics research, respectively. It was found that the activation energy of the ternary catalyst was lower than that of the binary catalyst and the single-component catalyst K2CO3. This is because the ternary catalyst is in a liquid state at a gasification temperature of 700-900℃, while the binary catalyst and the single-component catalyst K2CO3 are in a solid state. The liquid catalyst has good flowability and is more likely to diffuse into the reaction system, so the active sites of coal increase accordingly, and the activity is relatively high. It was also found that the accumulation or excess of sodium / potassium carbonate on the surface of coal is easy to stick and slag in a molten state, which has an adverse effect on the catalytic gasification process.

[0005] Therefore, it is urgent to develop an alkali metal catalyst which is not easy to be inactivated, resistant to high temperature, has good coal catalytic gasification effect, and is more easily dispersed uniformly, so as to break through the bottleneck of industrialization of coal catalytic gasification technology. SUMMARY

[0006] The present application aims to provide a high-temperature-resistant coal catalytic gasification catalyst and a preparation method thereof. The preparation process of the catalyst precursor greatly improves the uniformity, dispersibility and porosity of the coal base in the catalyst, and significantly improves the utilization rate of the active component and the activity of the catalyst when the active component is compounded.

[0007] To achieve the above-mentioned purpose, the present application proposes the following technical solutions:

[0008] In a first aspect, the present application discloses a preparation method of a high-temperature-resistant coal catalytic gasification catalyst, comprising the following steps:

[0009] 1) pyrolyzing a coal base to obtain semi-coke;

[0010] 2) impregnating the semi-coke with an organic metal salt of an alkali metal to obtain a catalyst precursor;

[0011] 3) modifying the catalyst precursor;

[0012] 4) using ion exchange process to modify the active component of the catalyst precursor, and post-treat the product to obtain the composite catalyst with high temperature resistance.

[0013] Further, the semi-coke prepared in step 1) comprises Fe2O3 8.85%, Al2O3 19.87%, SiO2 32.33%, K2O 18.69%, Cr2O3 1.55%, CaO 12.98%, NiO 0.82%, MgO 2.96%, Na2O 1.74%, and MnO 0.21%, based on the mass percentage of oxides and the total amount of the oxides being 100%.

[0014] Further, the reaction conditions for preparing the semi-coke in step 1) are as follows:

[0015] In the fluidized bed reactor, the coal base is heated to pyrolysis reaction completion under N2 / H2 atmosphere and at a temperature of 450-850°C; wherein the coal base is one or more of bituminous coal, lignite, peat, petroleum coke, or anthracite.

[0016] In the fluidized bed reactor, the coal base is heated to pyrolysis reaction completion under N2 / H2 atmosphere and at a temperature of 450-850°C; wherein the coal base is one or more of bituminous coal, lignite, peat, petroleum coke, or anthracite.

[0017] Further, the particle size of the semi-coke is 0.6-1 cm, and the porosity is 30-50%.

[0018] Further, the conditions for the impregnation treatment of the semi-coke with the organic metal salt of alkali metal in step 2) are as follows: the semi-coke is immersed in a reaction container containing a solution of the organic metal salt of alkali metal under N2 atmosphere, stirred at a temperature of 40-75°C for 2-5 h to obtain the catalyst precursor; wherein the organic metal salt of alkali metal is selected from one or any combination of sodium dodecyl benzene sulfonate, sodium oleate, potassium dodecyl benzene sulfonate, potassium oleate, and polyacrylamide potassium salt.

[0019] Further, the modification process of the catalyst precursor with the ammonium salt as the modifier in step 3) controls the PH of the mixed solution in the reaction container to be greater than 7.5.

[0020] Further, the ammonium salt is selected from one or more of (NH4)2CO3, NH4HCO3, NH4NO3, (NH4)2SO4, and NH4Cl.

[0021] Further, the active component in step 4) is selected from at least two of sodium salt, magnesium salt, potassium salt, calcium salt, manganese salt, iron salt, cobalt salt, and nickel salt.

[0022] Furthermore, the reaction conditions for the ion exchange process are as follows: ion exchange reaction temperature is 20–200℃, pressure is 0.1–1.6 MPa, and reaction time is 10–60 min.

[0023] Secondly, the present invention discloses a high-temperature resistant coal catalytic gasification catalyst, which is prepared by the above-mentioned method for preparing a high-temperature resistant coal catalytic gasification catalyst; wherein, the coal catalytic gasification catalyst comprises, by weight, 80-93% catalyst precursor, 2-5% modifier, and 5-15% active component.

[0024] As can be seen from the above technical solutions, the present invention achieves the following beneficial effects:

[0025] This invention discloses a high-temperature resistant coal catalytic gasification catalyst and its preparation method. The preparation process involves first obtaining semi-coke and impregnating it with an organometallic salt to form a catalyst precursor. Then, ammonium salts are used to modify the catalyst precursor to create composite active components, ultimately yielding a high-temperature resistant composite catalyst with a more uniform distribution of active components and excellent coal catalytic gasification performance. Specifically, it offers the following advantages:

[0026] 1. Pyrolysis of coal yields semi-coke, which is then impregnated in organometallic salts of alkali metals to form catalyst precursors, thereby improving the uniformity, dispersibility, and porosity of the coal.

[0027] 2. In the catalyst preparation process, ammonium salts are used to modify the catalyst precursor. By controlling the pH, the prepared composite catalyst is made weakly alkaline, which reduces the formation of insoluble potassium aluminum silicate during coal catalytic gasification and improves the utilization rate of active components.

[0028] 3. The active components in the composite catalyst have a lower melting point, which allows them to melt at a lower temperature and then penetrate into the pores of the coal-based material during the reaction, resulting in a more uniform distribution of the active components. At the same time, their good fluidity makes them easier to diffuse into the reaction system, thereby increasing the number of active sites in the coal.

[0029] It should be understood that all combinations of the foregoing concepts and the additional concepts described in more detail below can be considered part of the inventive subject matter of this disclosure, provided that such concepts do not contradict each other.

[0030] The foregoing and other aspects, embodiments, and features of the teachings of the present invention will be more fully understood from the following description in conjunction with the accompanying drawings. Other additional aspects of the invention, such as features and / or beneficial effects of exemplary embodiments, will become apparent from the following description or may be learned through practice of specific embodiments according to the teachings of the present invention. Attached Figure Description

[0031] The drawings are not drawn to scale. In the drawings, like reference numerals can be used to denote like parts throughout the various views. For the sake of clarity, not every component can be labeled in every drawing. Embodiments of various aspects of the application will now be described, by way of example only, with reference to the drawings in which:

[0032] Figure 1 Flow chart for preparation of catalyst for coal catalytic gasification of the present application;

[0033] Figure 2 TEM image of catalyst prepared for Comparative Example 1 of the present application;

[0034] Figure 3 TEM image of catalyst prepared for Example 12 of the present application. DETAILED DESCRIPTION

[0035] In order to make the objects, technical solutions, and advantages of the embodiments of the present application clearer, the technical solutions of the embodiments of the present application will be described below clearly and completely with reference to the drawings of the embodiments of the present application. Obviously, the described embodiments are some but not all of the embodiments of the present application. Based on the described embodiments of the present application, all other embodiments obtained by a person of ordinary skill in the art without creative effort should fall within the scope of the present application. Unless otherwise defined, the technical terms or scientific terms used herein should be understood as their common meanings to those having ordinary skill in the art to which the present application pertains.

[0036] The terms "first", "second", and similar terms used herein do not necessarily indicate any order, quantity, or importance, but are used to distinguish different components. Also, unless otherwise specified, the singular forms "a", "an", and "the" or similar referents do not necessarily limit the quantity to one but can mean one or more than one. The terms "including", "containing", and similar terms are intended to cover the elements or objects listed after the term "including", "containing", or similar terms, and are not limited to the elements or objects listed after the term "including", "containing", or similar terms. The terms "upper", "lower", "left", "right", and similar terms are used only to indicate relative positions, and can change when the absolute positions of the described objects change.

[0037] Based on the research, it is found that the simple alkali metal salt as catalyst in the coal catalytic gasification process application, although the early stage has achieved good catalytic effect, but with the long time use of catalyst, the accumulation of molten state sodium / potassium carbonate on the coal surface leads to mutual adhesion and slagging deactivation, thereby affecting the coal catalytic gasification effect, and the catalytic efficiency is significantly reduced. The present application aims at the problem, and proposes a high-temperature-resistant coal catalytic gasification catalyst and a preparation method thereof, which is not only high-temperature-resistant and has excellent catalytic effect, and is not easy to be deactivated.

[0038] Specifically as Figure 1 The preparation method of the high-temperature-resistant coal catalytic gasification catalyst disclosed by the present application comprises the following steps:

[0039] 1) The coal base is subjected to pyrolysis treatment to obtain semicoke; wherein the reaction conditions for pyrolysis treatment of the coal base to obtain semicoke are as follows: the coal base is heated to 450-850 DEG C under N2 / H2 atmosphere in a fluidized bed reactor until the pyrolysis reaction is completed; the coal base is one or more of bituminous coal, lignite, peat, petroleum coke or anthracite; the obtained semicoke comprises, in terms of mass percentage based on oxides and the total amount of the oxides being 100%, Fe2O3 8.85%, Al2O3 19.87%, SiO2 32.33%, K2O 18.69%, Cr2O3 1.55%, CaO 12.98%, NiO 0.82%, MgO 2.96%, Na2O 1.74%, MnO 0.21%, and the particle size of the semicoke is 0.6-1 cm and the porosity is 30-50%;

[0040] 2) The semicoke is subjected to impregnation treatment with an organic metal salt of alkali metal to obtain a catalyst precursor; wherein the impregnation treatment conditions are as follows: the semicoke is impregnated in a reaction container containing a solution of the organic metal salt of alkali metal under N2 atmosphere, and stirred at a temperature of 40-75 DEG C for 2-5 h to obtain the catalyst precursor; wherein the organic metal salt of alkali metal is selected from one or any combination of sodium dodecyl benzene sulfonate, sodium oleate, potassium dodecyl benzene sulfonate, potassium oleate and polyacrylamide potassium salt;

[0041] 3) The catalyst precursor is subjected to modification treatment with an ammonium salt as a modifier, and the PH of the mixed solution in the reaction container is controlled to be greater than 7.5 during the modification process; the ammonium salt is selected from one or more of (NH4)2CO3, NH4HCO3, NH4NO3, (NH4)2SO4 and NH4Cl;

[0042] 4) using ion exchange process to the modified catalyst precursor composite active component, the product after treatment, to obtain high temperature resistant composite catalyst; wherein the coal catalytic gasification catalyst by weight fraction, including catalyst precursor 80-93%, modifier 2-5%, active component 5-15%; ion exchange process reaction conditions are: ion exchange reaction temperature is 20-200℃, the pressure is 0.1-1.6 MPa, the reaction time is 10-60 min; active component is selected from at least two of sodium salt, magnesium salt, potassium salt, calcium salt, manganese salt, iron salt, cobalt salt, nickel salt.

[0043] The high temperature resistant coal catalytic gasification catalyst and the preparation method thereof disclosed by the present application will be further specifically introduced in combination with the specific embodiments shown in the accompanying drawings.

[0044] Example 1

[0045] Take 50g of 60-100 mesh anthracite coal and place it in a fluidized bed reactor. Heat the coal to 850℃ under N2 / H2 atmosphere, and keep the temperature until the coal-based pyrolysis reaction is completed to produce semi-coke. Place the semi-coke in a reaction kettle, and immerse the semi-coke in 0.25 mol / L sodium oleate under N2 atmosphere, with stirring for 5h at 75℃. Add NH4HCO3 dropwise to the prepared catalyst precursor for modification until the pH of the mixed solution is 8. After modification of the prepared precursor, perform ion exchange with 0.25 mol / L Na2CO3 and K2CO3, with an ion exchange reaction temperature of 200℃, a pressure of 0.1 MPa, and a reaction time of 60 min. After the reaction, perform post-treatment on the product, including washing, centrifugation, drying, and grinding, to produce a catalyst marked as S-1.

[0046] Example 2

[0047] Take 50g of 60-100 mesh anthracite coal and place it in a fluidized bed reactor. Heat the coal to 600℃ under N2 / H2 atmosphere, and keep the temperature until the coal-based pyrolysis reaction is completed to produce semi-coke. Place the semi-coke in a reaction kettle, and immerse the semi-coke in 0.25 mol / L sodium oleate under N2 atmosphere, with stirring for 5h at 75℃. Add NH4HCO3 dropwise to the prepared catalyst precursor for modification until the pH of the mixed solution is 8. After modification of the prepared precursor, perform ion exchange with 0.25 mol / L MgCO3 and K2CO3, with an ion exchange reaction temperature of 200℃, a pressure of 0.1 MPa, and a reaction time of 60 min. After the reaction, perform post-treatment on the product, to produce a catalyst marked as S-2.

[0048] Example 3

[0049] Take 60-100 mesh anthracite 50 g in the fluidized bed reactor, under N2 / H2 atmosphere, coal heating to 450℃, keep the temperature until the coal-based pyrolysis reaction is completed, the semi-coke is prepared; the semi-coke is placed in the reaction kettle, under N2 atmosphere, the semi-coke is immersed in 0.25 mol / L sodium oleate, the stirring time is 5h, the temperature is 75℃; to the prepared catalyst precursor, drop (NH4)2CO3 modification treatment, until the mixed solution PH is 8; after modification of the prepared precursor, ion exchange with 0.25 mol / L CoCO3, K2CO3, ion exchange reaction temperature is 200℃, pressure is 0.1 MPa, reaction time is 60 min; after the reaction, the product is treated, the prepared catalyst is marked as S-3.

[0050] Example 4

[0051] Take 60-100 mesh anthracite 50 g in the fluidized bed reactor, under N2 / H2 atmosphere, coal heating to 850℃, keep the temperature until the coal-based pyrolysis reaction is completed, the semi-coke is prepared. The semi-coke is placed in the reaction kettle, under N2 atmosphere, the semi-coke is immersed in 0.25 mol / L sodium dodecyl benzene sulfonate, the stirring time is 2h, the temperature is 75℃; to the prepared catalyst precursor, drop (NH4)2CO3 modification treatment, until the mixed solution PH is 9; after modification of the prepared precursor, ion exchange with 0.25 mol / L Ni(NO3)2, K2CO3, ion exchange reaction temperature is 20℃, pressure is 0.1 MPa, reaction time is 10 min; after the reaction, the product is treated, the prepared catalyst is marked as S-4.

[0052] Example 5

[0053] Take 60-100 mesh anthracite 50 g in the fluidized bed reactor, under N2 / H2 atmosphere, coal heating to 850℃, keep the temperature until the coal-based pyrolysis reaction is completed, the semi-coke is prepared. The semi-coke is placed in the reaction kettle, under N2 atmosphere, the semi-coke is immersed in 0.25 mol / L sodium dodecyl benzene sulfonate, the stirring time is 2h, the temperature is 75℃; to the prepared catalyst precursor, drop (NH4)2CO3 modification treatment, until the mixed solution PH is 9; after modification of the prepared precursor, ion exchange with 0.25 mol / L Ni(NO3)2, K2CO3, ion exchange reaction temperature is 20℃, pressure is 0.1 MPa, reaction time is 10 min; after the reaction, the product is treated, the prepared catalyst is marked as S-4.

[0054] Example 6

[0055] Take 60-100 purpose anthracite 50 g is placed in fluidized bed reactor, under N2 / H2 atmosphere coal heating to 850℃, keep this temperature until coal base pyrolysis reaction is completed, preparation semi-coke; The prepared semi-coke semi-coke is placed in reaction kettle, under N2 atmosphere, semi-coke is immersed in 0.25mol / L polyacrylamide potassium salt, stirring time is 5h, temperature is 75℃;To the prepared catalyst precursor, drop (NH4)2CO3 modification treatment, until mixed solution PH is 9;After modification to the prepared precursor, carry out ion exchange with the concentration of 0.25mol / L Ni(NO3)2, K2CO3, ion exchange reaction temperature is 20℃, pressure is 0.1MPa, reaction time is 10min;After reaction, the product is treated, and the prepared catalyst is marked as S-6.

[0056] Example 7

[0057] Take 60-100 purpose anthracite 50 g is placed in fluidized bed reactor, under N2 / H2 atmosphere coal heating to 850℃, keep this temperature until coal base pyrolysis reaction is completed, preparation semi-coke. The prepared semi-coke semi-coke is placed in reaction kettle, under N2 atmosphere, semi-coke is immersed in 0.25mol / L polyacrylamide potassium salt, stirring time is 5h, temperature is 75℃;To the prepared catalyst precursor, drop (NH4)2CO3 modification treatment, until mixed solution PH is 9;After modification to the prepared precursor, carry out ion exchange with the concentration of 0.25mol / L Ni(NO3)2, K2CO3, ion exchange reaction temperature is 20℃, pressure is 0.1MPa, reaction time is 10min;After reaction, the product is treated, and the prepared catalyst is marked as S-6.

[0058] Example 8

[0059] Take 60-100 purpose anthracite 50 g is placed in fluidized bed reactor, under N2 / H2 atmosphere coal heating to 850℃, keep this temperature until coal base pyrolysis reaction is completed, preparation semi-coke. The prepared semi-coke semi-coke is placed in reaction kettle, under N2 atmosphere, semi-coke is immersed in 0.25mol / L polyacrylamide potassium salt, stirring time is 5h, temperature is 75℃;To the prepared catalyst precursor, drop (NH4)2CO3 modification treatment, until mixed solution PH is 9;After modification to the prepared precursor, carry out ion exchange with the concentration of 0.25mol / L Ni(NO3)2, K2CO3, ion exchange reaction temperature is 20℃, pressure is 0.1MPa, reaction time is 10min;After reaction, the product is treated, and the prepared catalyst is marked as S-6.

[0060] Example 9

[0061] Take 60-100 purpose anthracite 50 g is placed in fluidized bed reactor, under N2 / H2 atmosphere coal heating to 850℃, keep this temperature until coal base pyrolysis reaction is completed, preparation semi-coke; The semi-coke is placed in the reactor, under N2 atmosphere, semi-coke is immersed in 0.25mol / L sodium oleate, stirring time is 5h, temperature is 75℃;To the catalyst precursor prepared drop NH4HCO3 modification treatment, until the mixed solution PH is 8;After modification to the prepared precursor, with the concentration of 0.25mol / L Ni (NO3) 2, K2CO3 ion exchange, ion exchange reaction temperature is 150℃, pressure is 0.2MPa, reaction time is 60min;After reaction, the product is treated, the catalyst prepared is marked as S-9.

[0062] Example 10

[0063] Take 60-100 purpose anthracite 50 g is placed in fluidized bed reactor, under N2 / H2 atmosphere coal heating to 850℃, keep this temperature until coal base pyrolysis reaction is completed, preparation semi-coke; The semi-coke is placed in the reactor, under N2 atmosphere, semi-coke is immersed in 0.25mol / L sodium oleate, stirring time is 5h, temperature is 75℃;To the catalyst precursor prepared drop NH4HCO3 modification treatment, until the mixed solution PH is 8;After modification to the prepared precursor, with the concentration of 0.25mol / L Ni (NO3) 2, K2CO3 ion exchange, ion exchange reaction temperature is 150℃, pressure is 0.2MPa, reaction time is 60min;After reaction, the product is treated, the catalyst prepared is marked as S-9.

[0064] Example 11

[0065] Take 60-100 purpose anthracite 50 g is placed in fluidized bed reactor, under N2 / H2 atmosphere coal heating to 850℃, keep this temperature until coal base pyrolysis reaction is completed, preparation semi-coke; The semi-coke is placed in the reactor, under N2 atmosphere, semi-coke is immersed in 0.25mol / L sodium oleate, stirring time is 5h, temperature is 75℃;To the catalyst precursor prepared drop NH4HCO3 modification treatment, until the mixed solution PH is 8;After modification to the prepared precursor, with the concentration of 0.25mol / L Ni (NO3) 2, K2CO3 ion exchange, ion exchange reaction temperature is 150℃, pressure is 0.2MPa, reaction time is 60min;After reaction, the product is treated, the catalyst prepared is marked as S-9.

[0066] Example 12

[0067] Take 60-100 mesh anthracite 50 g in the fluidized bed reactor, under N2 / H2 atmosphere, coal heating to 850℃, keep the temperature until the coal-based pyrolysis reaction is completed, the semi-coke is prepared; the semi-coke is placed in the reactor, under N2 atmosphere, the semi-coke is immersed in 0.25 mol / L potassium oleate, the stirring time is 5h, the temperature is 75℃; drop the NH4HCO3 modification treatment to the prepared catalyst precursor, until the mixed solution PH is 8; after the modification of the prepared precursor, ion exchange with 0.25 mol / L K2CO3, Mn(NO3)2, Ni(NO3)2, the ion exchange reaction temperature is 150℃, the pressure is 0.2MPa, the reaction time is 60min; after the reaction, the product is treated, the prepared catalyst is marked as S-12.

[0068] Comparative example 1

[0069] Take 60-100 mesh anthracite 50 g in the fluidized bed reactor, under N2 / H2 atmosphere, coal heating to 850℃, keep the temperature until the coal-based pyrolysis reaction is completed, the semi-coke is prepared; the semi-coke is placed in the reactor, under N2 atmosphere, the semi-coke is immersed in 0.25 mol / L potassium oleate, the stirring time is 5h, the temperature is 75℃; drop the NH4HCO3 modification treatment to the prepared catalyst precursor, until the mixed solution PH is 8; after the modification of the prepared precursor, ion exchange with 0.25 mol / L K2CO3, Mn(NO3)2, Ni(NO3)2, the ion exchange reaction temperature is 150℃, the pressure is 0.2MPa, the reaction time is 60min; after the reaction, the product is treated, the prepared catalyst is marked as S-12.

[0070] Catalyst performance evaluation

[0071] Evaluation conditions: gasification temperature 700℃, gasification pressure 3.5Mpa, initial water-coal ratio 2g / g·min -1 , carrier gas (Ar gas) flow rate 1L / min. The fixed bed reactor is 32mm in diameter and 800mm in height. The product gas enters the separation tank for gas-liquid separation, the separated gas is dehumidified by the dryer, measured by the wet flowmeter, then collected by the gas bag, finally analyzed by GC for the product gas composition and content in each time period. See Table 1 for specific analysis data.

[0072] Table 1 Reaction time 300min coal gasification conversion rate, methane generation amount and methane content

[0073]

[0074] From the catalytic data of Table 1, it can be seen that in the coal catalytic gasification reaction, under the same experimental conditions, the conversion rate of coal gasification to gas phase products is the highest for the S-12 catalyst prepared according to the method of the present application, and the conversion rate reaches 89.1% at a reaction time of 300 min, the cumulative amount of methane generated reaches 12.9 mmol·g -1 , the content of methane in the product reaches 26.4%, showing excellent methanation performance.

[0075] For this reason, the catalyst S-12, S-13 and raw coal are analyzed from the perspective of microstructure to explain the reason for the excellent catalytic performance of S-12.

[0076] Table 2 BET full analysis data of catalyst

[0077] Catalyst Pore volume ml / g Average pore diameter nm Specific surface area m 2 / g]] S-13 0.0050 8.411 1.188 S-12 0.0059 6.498 2.146 Raw coal 0.0081 6.667 2.434

[0078] Combined with the BET pore size analysis data, it is shown that compared with the raw coal, the catalyst S-12 and S-13 have changed the pore structure of the raw coal to different degrees, and the pore volume and specific surface area are reduced; among them, the catalyst S-12 has a larger pore volume and a smaller average pore size, but still has a rich pore structure and a larger specific surface area. However, further research on the distribution of active components in the catalyst found that only a few potassium carbonate molecules in the catalyst S-13 entered the surface pores of the semicoke, and most of them existed on the surface of the coal powder, and the dispersion was poor, and there was obvious accumulation phenomenon, as shown in Figure 2 ; while Figure 3 As shown in the micrograph of catalyst S-12, it can be clearly seen that the potassium oleate molecules are uniformly dispersed in the coal powder, and no accumulation phenomenon exists; the reason is that the oil-philic group anion of potassium oleate improves the binding ability of alkali metal ions to the surface of coal, so that the potassium ions are fully and uniformly dispersed on the surface of coal. In summary, the catalyst S-12 has a rich pore structure and a larger specific surface area, and the active components in the modified catalyst are fully and uniformly dispersed on the surface of the coal, thereby showing excellent methanation performance.

[0079] Although the present application has been disclosed with reference to the preferred embodiments above, it is not intended to limit the present application. Those skilled in the art without departing from the spirit and scope of the present application can make various modifications and improvements. Therefore, the protection scope of the present application shall be subject to the definition of the claims.

Claims

1. A method for preparing a high-temperature resistant coal catalytic gasification catalyst, characterized in that, Includes the following steps: 1) Pyrolysis of coal-based materials yields semi-coke; 2) The semi-coke is impregnated with an organometallic salt of an alkali metal to obtain a catalyst precursor; 3) Modify the catalyst precursor; 4) The modified catalyst precursor is combined with active components using ion exchange process, and the product is post-treated to obtain a high-temperature resistant composite catalyst. The reaction conditions for the pyrolysis treatment in step 1) are as follows: in a fluidized bed reactor, under a N2 / H2 atmosphere and at a temperature of 450-850℃, the coal-based material is heated until the pyrolysis reaction is completed; the organometallic salt of the alkali metal in step 2) is selected from one or any combination of sodium dodecylbenzenesulfonate, sodium oleate, potassium dodecylbenzenesulfonate, potassium oleate, and potassium polyacrylamide. Based on the mass percentage of oxides and the total amount of said oxides being 100%, the semi-coke obtained in step 1) comprises: Fe2O3 8.85%, Al2O3 19.87%, SiO2 32.33%, K2O 18.69%, Cr2O3 1.55%, CaO 12.98%, NiO 0.82%, MgO 2.96%, Na2O 1.74%, and MnO 0.21%. The semi-coke has a particle size of 0.6~1cm and a porosity of 30~50%; In step 3), ammonium salt is used as a modifier to modify the catalyst precursor. During the modification process, the pH of the mixed solution in the reaction vessel is controlled to be greater than 7.

5.

2. The method for preparing the high-temperature resistant coal catalytic gasification catalyst according to claim 1, characterized in that, The coal base in step 1) is one or more of bituminous coal, lignite, peat, petroleum coke, or anthracite.

3. The method for preparing the high-temperature resistant coal catalytic gasification catalyst according to claim 1, characterized in that, The conditions for the semi-coke impregnation treatment using an organometallic salt of an alkali metal in step 2) are as follows: Under a nitrogen atmosphere, the semi-coke is impregnated in a reaction vessel containing an organometallic salt solution of the alkali metal, and stirred at a temperature of 40-75°C for 2-5 hours to obtain a catalyst precursor.

4. The method for preparing the high-temperature resistant coal catalytic gasification catalyst according to claim 1, characterized in that, The ammonium salt is selected from one or more of (NH4)2CO3, NH4HCO3, NH4NO3, (NH4)2SO4, and NH4Cl.

5. The method for preparing the high-temperature resistant coal catalytic gasification catalyst according to claim 1, characterized in that, The active component in step 4) is at least two of the following: sodium salt, magnesium salt, potassium salt, calcium salt, manganese salt, iron salt, cobalt salt, and nickel salt.

6. The method for preparing the high-temperature resistant coal catalytic gasification catalyst according to claim 5, characterized in that, The reaction conditions for the ion exchange process are as follows: ion exchange reaction temperature is 20~200℃, pressure is 0.1~1.6MPa, and reaction time is 10~60min.

7. A high-temperature resistant coal catalytic gasification catalyst, characterized in that, The high-temperature resistant coal catalytic gasification catalyst is prepared by the method according to any one of claims 1-6; wherein, the coal catalytic gasification catalyst comprises, by weight, 80-93% catalyst precursor, 2-5% modifier, and 5-15% active component; and the high-temperature resistant coal catalytic gasification catalyst, when applied to a coal catalytic gasification reaction at 700℃ for 300 min, achieves a maximum conversion rate of 89.1% and a maximum methane production of 12.9 mmol·g. -1 .

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