Coal catalytic gasification reaction method and application of perovskite type catalyst in coal catalytic gasification reaction

Abstract

The invention relates to the field of coal catalytic gasification reaction, and discloses a coal catalytic gasification reaction method and application of a perovskite type catalyst in coal catalytic gasification reaction, the catalyst comprises an A2B2O5 type perovskite material, an A site element is Ca and / or Sr, and a B site element is at least one of Fe, Mn, Ni and Co. The application of the catalyst in the catalytic coal gasification reaction can improve the catalytic coal gasification reaction rate and reduce the gasification temperature.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of coal catalytic gasification reaction, and particularly relates to a coal catalytic gasification reaction method and application of a perovskite catalyst in coal catalytic gasification reaction. BACKGROUND

[0002] Coal gasification technology is a clean coal technology, and is also a key technology for developing coal-based chemicals (ammonia, methanol, acetic acid, olefins, etc.), coal-based liquid fuels (dimethyl ether, gasoline, etc.), hydrogen production, integrated coal gasification combined cycle power generation system (IGCC), and integrated coal gasification fuel cell combined power generation (IGFC). Developing multi-production technology with coal gasification technology as the core has become a hot technology and an important development direction for efficient and clean utilization of coal in various countries. However, traditional coal gasification technology faces some challenges, including high temperature and high pressure, low reaction rate, low carbon conversion rate, and poor economy, which are the main obstacles to the progress of coal gasification technology. The addition of catalysts helps to overcome these problems, enabling coal gasification reaction to proceed under milder conditions, significantly reducing energy consumption and reducing the requirements for equipment materials. This not only improves the gasification rate, but also has a positive impact on desulfurization, dust removal, and environmental protection. Iron-based oxides and calcium-based oxides are widely used in coal catalytic gasification due to their high catalytic activity, but iron-based oxides are prone to carbon deposition at high temperatures, and calcium-based oxides are prone to deactivation and volatilization at high temperatures, which significantly reduces their activity, limiting their application in industry.

[0003] As one of the methods for efficient and clean utilization of coal, coal gasification process is favored by people due to its wide range of applications, ability to obtain product gas of different compositions as needed, and use of various types of reactors. A large number of laboratory studies have reached the level of industrial methods, but how to further improve the efficiency of coal gasification and optimize the composition of product gas has always been the goal of coal gasification researchers. In order to further improve the efficiency of coal gasification and reduce the gasification temperature, people have been considering coal catalytic gasification for more than a hundred years.

[0004] The catalysts for coal catalytic gasification studied so far almost include all the metal elements in the periodic table. There are mainly the following several categories: (1) metal oxides, metal hydroxides and salts mainly containing alkali metals and alkaline earth metals, including NaOH, KOH, CaCO3, K2CO3, Na2CO3, CaO, etc.; (2) transition metals, mainly including iron, cobalt, nickel, etc., among which Ni shows better catalytic activity; (3) rare earth metals, mainly Ce(NO3)3, considering the factors of high price and low catalytic activity, so far the research on coal gasification using rare earth metals as catalyst has not aroused the actual interest of people; (4) minerals or ash in coal, no matter which coal, more or less contains a certain amount of minerals. However, due to the difference in region and coal type, the amount and composition of the contained minerals are quite different.

[0005] Therefore, in order to better meet the needs of the coal catalytic gasification industry, it is urgent to explore new catalysts to improve the gasification efficiency and economy. SUMMARY

[0006] The purpose of the present application is to overcome the problems of slow coal catalytic gasification reaction rate and high gasification temperature in the prior art, and to provide a coal catalytic gasification reaction method and application of a perovskite catalyst in coal catalytic gasification reaction, which can improve the coal catalytic gasification reaction rate and reduce the gasification temperature.

[0007] In order to achieve the above purpose, the first aspect of the present application provides an application of a perovskite catalyst in coal catalytic gasification reaction, wherein the catalyst comprises a A2B2O5 type perovskite material, wherein the A site element is Ca and / or Sr, and the B site element is at least one of Fe, Mn, Ni and Co.

[0008] The second aspect of the present application provides a coal catalytic gasification reaction method, wherein the method comprises: contacting the catalyst, the carbon-containing raw material and the gasification agent to perform coal catalytic gasification reaction; The catalyst comprises a A2B2O5 type perovskite material, wherein the A site element is Ca and / or Sr, and the B site element is at least one of Fe, Mn, Ni and Co. The mass ratio of the catalyst to the carbon-containing raw material is 1:4-11.

[0009] Preferably, the mass ratio of the catalyst to the carbon-containing raw material is 1:4-10.

[0010] Preferably, the initial gasification temperature of the coal catalytic gasification reaction is 900-1100℃.

[0011] By the technical scheme, the catalyst including the A2B2O5 type perovskite material is applied in the coal catalytic gasification reaction, the initial gasification temperature and the end gasification temperature of the carbon-containing raw material can be significantly reduced, the maximum gasification rate of the carbon-containing raw material can be improved, the coal catalytic gasification reaction rate can be accelerated, the gasification reaction time can be shortened, and the gasification efficiency can be improved, specifically, the initial gasification temperature of the coal coke can be reduced to 969.06 DEG C, the end gasification temperature can be reduced to 1093.46 DEG C, and the rate can also be improved to 20.18 % / min. BRIEF DESCRIPTION OF DRAWINGS

[0012] Figure 1 is an XRD pattern of the catalyst prepared in Preparation Example 1; Figure 2a and Figure 2b are respectively SEM and EDS data patterns of the catalyst prepared in Preparation Example 1 under different shooting scales; Figure 3a and Figure 3b are respectively mapping and particle size distribution patterns of the catalyst prepared in Preparation Example 1 under 100 nm; Figure 4a 、 Figure 4b 、 Figure 4c and Figure 4d are respectively XPS spectrum and O element, Fe 2p and Ca 2p spectrum of the catalyst prepared in Preparation Example 1; Figure 5 is a gasification characteristic TG, DTG curve diagram of the catalyst prepared in Preparation Example 1, Comparative Example 3 and Example 1; Figure 6 is a gasification characteristic TG, DTG curve diagram of Example 2; Figure 7 is a gasification characteristic TG, DTG curve diagram of Example 3; Figure 8 is a gasification characteristic TG, DTG curve diagram of Example 4; Figure 9 is a gasification characteristic TG, DTG curve diagram of Example 5; Figure 10 is a gasification characteristic TG, DTG curve diagram of Example 6; Figure 11a is a gasification characteristic TG, DTG curve diagram of Comparative Example 3; Figure 11b is a gasification characteristic TG, DTG curve diagram of Comparative Preparation Example 3; Figure 12 is a gasification characteristic TG, DTG curve diagram of Comparative Example 1; Figure 13 is a gasification characteristic TG, DTG curve diagram of Comparative Example 2; Figure 14 Raman spectra of Preparation Example 1 and Comparative Preparation Example 3. DETAILED DESCRIPTION

[0013] The endpoints of the ranges and any values described herein are not limited to the precise values stated. The ranges and values should be construed to be roughly about the ranges and values. Individual endpoints of the ranges, the endpoints of the ranges and the individual point values can be combined with one another to form one or more new ranges, which are to be considered as being specifically disclosed herein.

[0014] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application; the use of the terms "including," "comprising," "having" and "with" used herein are specifically intended to be open-ended and do not exclude the presence of other components, steps or features. The description herein of any aspects of the application using terms such as "comprising", "having", "including" or "with" to describe the presence of a feature or features in described combinations are specifically intended to be open-ended and do not exclude the presence of additional

[0015] In the present application, the term "comprising" or "including" is an open term, i.e. it includes the stated features but not excluding other features.

[0016] In the present application, all percentages, parts, ratios, etc. are based on weight unless otherwise indicated. All such weights as they come to be used or considered are in a consolidated form, not in a molecular dispersion.

[0017] In the present application, "first" and "second" do not indicate any order or limitation to the materials or steps, but are used to distinguish the materials or steps from each other, unless otherwise specified. For example, "first protective atmosphere" and "second protective atmosphere" are used to distinguish the protective atmospheres from each other.

[0018] The first aspect of the present application provides a perovskite catalyst for use in catalytic gasification of coal, wherein the catalyst comprises a perovskite material of A2B2O5 type, wherein A site elements are Ca and / or Sr, and B site elements are at least one of Fe, Mn, Ni and Co.

[0019] The catalyst of the present application comprises a perovskite material of A2B2O5 type, which enables the catalyst to have high catalytic activity in the catalytic gasification of coal, significantly reduces the initial and final gasification temperatures of coal char, increases the maximum gasification rate of coal char, increases the rate of coal catalytic gasification, shortens the reaction time, and improves the gasification efficiency.

[0020] The size distribution of the catalyst particles is preferably 50-350nm, and more preferably 50-300nm.

[0021] The particle size distribution of the catalyst is obtained by scanning electron microscopy.

[0022] According to the present application, the catalyst preferably has a spherical morphology.

[0023] The catalyst with the above-mentioned size and morphology is more conducive to reducing the initial and final gasification temperatures of coal char and improving the gasification efficiency.

[0024] The morphology of the catalyst is tested by scanning electron microscopy.

[0025] The oxygen vacancy of the A2B2O5 perovskite material has a wide selection range, and the catalyst is characterized by XPS, and the oxygen vacancy content in the catalyst is 20-30%.

[0026] The oxygen vacancy is obtained by the O1s peak separation method of XPS. Specifically, the oxygen vacancy area obtained by peak separation is divided by the oxygen vacancy, lattice oxygen and OH - The area of oxygen.

[0027] According to the present application, the A-site element is preferably Ca, and the B-site element is preferably Fe.

[0028] According to a particularly preferred embodiment of the present application, the catalyst comprising the Ca2Fe2O5 perovskite material can improve the gasification efficiency, and further preferably, the catalyst is a Ca2Fe2O5 perovskite material. The catalyst with the above-mentioned chemical composition is more conducive to accelerating the coal catalytic gasification reaction rate and shortening the gasification reaction time.

[0029] In the present application, the Ca2Fe2O5 perovskite material refers to a compound with a layered crystal structure composed of Ca, Fe and O elements.

[0030] It should be noted that the Ca2Fe2O5 perovskite material in the present application also has oxygen vacancies.

[0031] The inventors of the present application find in research that controlling the oxygen vacancy in the Ca2Fe2O5 type perovskite catalyst within a suitable range can further improve the catalytic activity of the catalyst. According to the present application, preferably, the catalyst is characterized by XPS, and the oxygen vacancy content in the catalyst is 23-26%, for example, can be 23%, 24%, 25%, 26%, or can be a range consisting of any of the above values, which can greatly improve the surface adsorption efficiency of carbon dioxide, strengthen the electron transfer process, and thus significantly enhance the coal gasification reaction activity, improve the coal catalytic gasification reaction rate, and reduce the gasification temperature.

[0032] In the present application, XRD is used to test the composition of the catalyst.

[0033] The source of the A2B2O5 type perovskite material in the present application has a wide selection range, which can be obtained from commercial or any known method in the art to meet the composition and morphology requirements.

[0034] According to the present application, preferably, the catalyst is prepared by sol-gel high-temperature calcination coupling method, which can accelerate the coal catalytic gasification reaction rate, shorten the gasification reaction time, and thus improve the gasification efficiency.

[0035] According to some preferred embodiments of the present application, the preparation method of the catalyst comprises: (1) mixing the A-site element source, the B-site element source, the chelating agent, and the crosslinking agent in the presence of a solvent to form a gel; (2) drying and calcining the gel.

[0036] In the present application, the catalyst prepared by the above method is more conducive to improving the dispersity of each element in the catalyst, improving the performance of the catalyst, more conducive to reducing the initial gasification temperature and the end gasification temperature of the carbon-containing raw material, and can improve the maximum gasification rate of the carbon-containing raw material, accelerate the coal catalytic gasification reaction rate, shorten the gasification reaction time, and improve the gasification efficiency.

[0037] In the present application, the A-site element source, the B-site element source, and the solvent are first mixed to obtain a first mixed solution; the chelating agent, the crosslinking agent, and the solvent are second mixed to obtain a second mixed solution; and the second mixed solution and the first mixed solution are third mixed to form a gel.

[0038] According to some specific embodiments of the present application, preferably, the molar concentration of the A-site element source in the first mixed solution is 0.1-0.3 mol / L. For example, it can be 0.1 mol / L, 0.2 mol / L, 0.3 mol / L, or can be a range consisting of any of the above values.

[0039] According to some embodiments of the present application, preferably, the molar concentration of the chelating agent in the second mixed solution is 0.3-0.5 mol / L. For example, it can be 0.3 mol / L, 0.4 mol / L, 0.5 mol / L, or a range consisting of any of the above values.

[0040] According to the present application, the molar ratio of the A-site element source and the B-site element source is selected from a wide range, preferably, the molar ratio of the A-site element source and the B-site element source is 1:0.8-1.2, for example, it can be 1:0.8, 1:0.9, 1:1, 1:1.1, 1:1.2, or a range consisting of any of the above values. By selecting the molar ratio of the A-site element source and the B-site element source in the above range, it is more conducive to preparing the catalyst for coal catalytic gasification reaction.

[0041] According to a particularly preferred embodiment of the present application, the A-site element source is a calcium source, and the B-site element source is an iron source.

[0042] The present application selects a wide range of calcium sources, preferably, the calcium source is selected from at least one of calcium acetate, calcium nitrate, and calcium sulfate, more preferably calcium acetate.

[0043] The present application selects a wide range of iron sources, preferably, the iron source is selected from at least one of iron nitrate, iron sulfate, and iron acetate, more preferably iron nitrate.

[0044] The calcium source or the iron source can also contain crystal water, which is not particularly limited by the present application.

[0045] The present application selects a wide range of the molar ratio of the chelating agent and the cross-linking agent, preferably, the molar ratio of the chelating agent and the cross-linking agent is 1:0.8-1.2, for example, it can be 1:0.8, 1:0.9, 1:1, 1:1.1, 1:1.2, or a range consisting of any of the above values. By selecting the molar ratio of the chelating agent and the cross-linking agent in the above range, it is more conducive to preparing the catalyst for coal catalytic gasification reaction.

[0046] The present application selects a wide range of chelating agents, preferably, the chelating agent is selected from citric acid and / or ethylenediaminetetraacetic acid, more preferably citric acid.

[0047] The present application selects a wide range of cross-linking agents, preferably, the cross-linking agent is selected from at least one of ethylene glycol, 1,4-butanediol, and 1,6-hexanediol, more preferably ethylene glycol. Adding the above cross-linking agent is more conducive to promoting the formation of gel.

[0048] The present application does not particularly limit the type of solvent as long as it can dissolve all the components added in the process of preparing the catalyst, for example, it can be water.

[0049] According to the present application, preferably, the mixing condition comprises: temperature 80-90℃, for example, can be 80℃, 82℃, 84℃, 86℃, 88℃, 90℃, or can be a range consisting of any of the above values, more preferably 84-88℃; mixing time is 2-5h, for example, can be 2h, 3h, 4h, 5h, or can be a range consisting of any of the above values, more preferably 3-5h.

[0050] The present application has a wide range of dry conditions, preferably, the drying condition comprises: temperature 100-150℃, for example, can be 100℃, 110℃, 120℃, 130℃, 140℃, 150℃, or can be a range consisting of any of the above values; time is 8-12h, for example, can be 8h, 9h, 10h, 11h, 12h, or can be a range consisting of any of the above values.

[0051] According to the present application, preferably, the calcination is carried out under a first protective atmosphere.

[0052] According to the present application, preferably, the first protective atmosphere is selected from at least one of argon, helium and nitrogen.

[0053] According to the present application, preferably, the calcination comprises low-temperature calcination first, and then high-temperature calcination.

[0054] According to the present application, preferably, the low-temperature calcination has a temperature of 350-450℃, for example, can be 350℃, 370℃, 400℃, 420℃, 450℃, or can be a range consisting of any of the above values, more preferably 390-420℃; time is 2-5h, for example, can be 2h, 3h, 4h, 5h, or can be a range consisting of any of the above values, more preferably 3-5h.

[0055] According to the present application, preferably, the high-temperature calcination has a temperature of 850-950℃, for example, can be 850℃, 870℃, 900℃, 920℃, 950℃, or can be a range consisting of any of the above values, more preferably 890-920℃; time is 3-5h, for example, can be 3h, 4h, 5h, or can be a range consisting of any of the above values, more preferably 4-5h.

[0056] In the present application, the calcination treatment is carried out in the above-mentioned preferred temperature range, which is more advantageous to improve the performance of the catalyst, and can better reduce the initial gasification temperature and end reaction temperature in the coal catalytic gasification reaction, while improving the gasification rate, avoiding the collapse and agglomeration of the catalyst structure caused by too high temperature, leading to performance decline.

[0057] The second aspect of the present application provides a method for coal catalytic gasification reaction, wherein the method comprises: contacting the catalyst with a carbon-containing raw material and a gasification agent to perform a coal catalytic gasification reaction; The catalyst comprises a perovskite material of A2B2O5 type, wherein the A site element is Ca and / or Sr, and the B site element is at least one of Fe, Mn, Ni and Co. The mass ratio of the catalyst to the carbon-containing raw material is 1:4-11.

[0058] The inventors of the present application found in the experiment that the catalyst comprising a perovskite material of A2B2O5 type has high catalytic reaction activity in the coal catalytic gasification reaction, which can not only significantly reduce the initial gasification temperature and the end gasification temperature of the coal char, but also increase the maximum gasification rate of the coal char, which indicates that the reaction can be performed under relatively mild conditions and the coal catalytic gasification reaction rate is accelerated and the gasification reaction time is shortened, thereby improving the gasification efficiency.

[0059] It should be noted that in the present application, the carbon-containing raw material is a raw material that can chemically react with the gasification agent to generate combustible gas (such as carbon monoxide, hydrogen, etc.).

[0060] It should be noted that in the present application, the gasification agent can convert the carbon in the coal into combustible gas (such as hydrogen, carbon monoxide, etc.).

[0061] The size distribution, morphology, type selection, oxygen vacancy content, preparation method and characterization method of the catalyst in the present application are the same as described above, and will not be described here.

[0062] According to the present application, preferably, the method further comprises: loading the catalyst on the carbon-containing raw material, and then contacting with the gasification agent. By loading the catalyst on the carbon-containing raw material, the contact between the catalyst and the reactants can be enhanced, and the reaction rate can be improved.

[0063] The present application has a wide range of choices for the loading method, and preferably, the loading method is selected from at least one of impregnation method, dry mixing method and ion exchange method.

[0064] According to the present application, preferably, the mass ratio of the catalyst to the carbon-containing raw material is 1:4-10. For example, it can be 1:4, 1:5, 1:6, 1:7, 1:8, 1:9, 1:10, or a range composed of any of the above values. By making the mass ratio of the catalyst to the carbon-containing raw material within the above preferred range, the activity of the coal catalytic gasification reaction can be more improved, the reaction rate can be faster, and the reaction time can be shorter.

[0065] The present application has a wide range of choices for the carbon-containing raw material, and preferably, the carbon-containing raw material is selected from at least one of coal char, lignite, bituminous coal, coke, semi-coke and petroleum coke, and more preferably, the carbon-containing raw material is coal char.

[0066] The source of the carbon-containing raw material is not particularly limited in the present application, and the carbon-containing raw material can be prepared by a method known in the art, such as carbonization, hydrothermal method, etc., which is well known to those skilled in the art. The specific preparation conditions and operations of the carbon-containing raw material are not particularly limited in the present application, and the preparation conditions of the carbon-containing raw material known in the prior art can be used.

[0067] The present application has a wide range of choices for the type of gasification agent, preferably, the gasification agent is selected from at least one of carbon dioxide, liquid water, water vapor, by using the above-mentioned type of gasification agent, the carbon in coal can be converted into combustible gas (such as hydrogen, carbon monoxide, etc.), thereby realizing efficient conversion and utilization of coal, more preferably carbon dioxide. Using carbon dioxide as a gasification agent, not only more conducive to the resource utilization of carbon dioxide generated in industry, but also can significantly improve the efficiency of the gasification reaction and the quality of the product. The reason may be that carbon dioxide as an active component participates in the gasification reaction, and plays its dual function of containing oxygen and carbon, thereby reducing the oxygen consumption in the reaction. At the same time, the participation of carbon dioxide can react with carbon in coal to generate carbon monoxide, which can increase the content of CO in the synthesis gas, reduce the relative emission amount of CO2, and thus improve the overall quality of the gasification gas.

[0068] According to the present application, preferably, the space velocity of the gasification agent is 750-900 h -1 , which is conducive to improving the gasification efficiency and shortening the reaction time, more preferably 800-900 h -1 .

[0069] According to the present application, preferably, the coal catalytic gasification reaction is carried out under a second protective atmosphere.

[0070] The present application has a wide range of choices for the protective atmosphere, preferably, the second protective atmosphere is selected from argon and / or nitrogen.

[0071] According to the present application, preferably, the initial gasification temperature of the coal catalytic gasification reaction is 900-1100℃, for example, it can be 900℃, 1000℃, 1100℃, or it can be a range consisting of any of the above values, more preferably 950-1000℃, further preferably 950-970℃. By making the initial gasification temperature of the coal catalytic gasification reaction in the above preferred range, it is more conducive to reducing the activation energy of the reaction, so that the reaction can be carried out under relatively mild conditions. At the same time, the gasification efficiency is improved, and the reaction time is shortened.

[0072] According to a particularly preferred embodiment of the present application, the catalyst is a Ca2Fe2O5 type perovskite material, the carbon-containing raw material is at least one selected from coal coke, lignite, bituminous coal, coke, semi-coke, and petroleum coke, the gasifying agent is at least one of carbon dioxide, liquid water, and water vapor, and the mass ratio of the catalyst to the carbon-containing raw material is 1:4-10. The above preferred combination is advantageous for further increasing the coal catalytic gasification reaction rate and reducing the gasification temperature.

[0073] The present application will be described in detail below through examples.

[0074] In the following examples and comparative examples, unless otherwise specified, the methods are conventional methods; the reagents, materials, and instruments used, unless otherwise specified, are commercially available and / or prepared by methods known in the art.

[0075] In the following examples and comparative examples, the characterization methods of the size, morphology, and composition of the catalysts are as described above and will not be repeated here.

[0076] In the following examples, XPS is used to test the surface composition and element valence of the catalysts.

[0077] In the following examples and comparative examples, the weight loss rate X of the sample can be calculated according to the relevant data obtained from the experiment, (Formula 1) wherein, in the formula, M0 is the mass at the beginning of the thermogravimetric experiment, M t is the weight of the sample at any time during the temperature programmed process, and in the present application, the higher the weight loss rate of the carbon-containing raw material, the better the effect.

[0078] In the following examples and comparative examples, the gasification reaction rate is calculated, and the vertical coordinate in the weight loss rate graph represents the gasification reaction rate which is the first-order integral of the weight loss rate with respect to time obtained in (Formula 1), and the gasification reaction rate W of the sample can be obtained, (Formula 2) In the present application, the larger the absolute value of the maximum gasification reaction rate W, the faster the reaction and the better the effect.

[0079] The following preparation examples are used to illustrate the preparation of the catalysts in the present application.

[0080] Preparation Example 1 First, 3.56 g (0.02 mol) of calcium acetate and 8.08 g (0.02 mol) of iron nitrate nonahydrate were added into 100 mL of deionized water, and then 8.41 g (0.04 mol) of citric acid and 2.23 mL (0.04 mol) of ethylene glycol were added into 100 mL of deionized water. After the solid was dissolved, the citric acid and ethylene glycol solution was slowly added into the above metal salt solution. The mixture was stirred at 85°C for 4 h, and then dried in an oven at 120°C for 10 h to obtain a Ca2Fe2O5 precursor.

[0081] The Ca2Fe2O5 precursor was high-temperature calcined under a protective atmosphere (high-purity Ar) at a temperature increasing rate of 5 ℃ / min to 400°C for 3 h, and then high-temperature calcined at a temperature increasing rate of 5 ℃ / min to 900°C for 4 h to obtain a perovskite Ca2Fe2O5 catalyst, which was naturally cooled to room temperature after the calcination was completed.

[0082] The Ca2Fe2O5 catalyst was subjected to XRD detection, and the results are shown in Figure 1 It can be seen that the XRD diffraction peak position of the synthesized Ca2Fe2O5 catalyst is consistent with the simulation data, proving that the pure-phase Ca2Fe2O5 oxide is successfully synthesized by the sol-gel method.

[0083] The micro-morphology and structure of the Ca2Fe2O5 catalyst were analyzed by SEM characterization, as shown in Figure 2a and Figure 2b The dispersion of each element was studied by mapping, as shown in Figure 3a and Figure 3b From Figure 2a , 2b it can be seen that the Ca2Fe2O5 catalyst has a close spherical structure from the shooting scale of 5 μm to 100 nm. The particle surface is relatively smooth, Figure 3b and the particle size distribution diagram shows that the particle diameter is 100-250 nm. From the mapping of Figure 3a it can be seen that the elements Fe, Ca, and O are uniformly distributed without agglomeration after high-temperature calcination.

[0084] The surface composition and element valence of the catalyst were analyzed by measuring the XPS spectrum to analyze the internal structure and activity relationship of the Ca2Fe2O5 catalyst. From the full spectrum of Figure 4a it can be seen that the surface of the catalyst is composed of C, O, Ca, and Fe. The O 1s spectrum is shown in Figure 4b which shows that the peak located at about 529.9 eV is attributed to the lattice oxygen (O 2-), while the peak around 531.57 eV is usually attributed to defect oxygen, and the peak around 532.79 eV corresponds to hydroxyl species (OH - ), and from the fitted peak area, it can be known that there are 24.96% oxygen vacancies in Ca2Fe2O5 catalyst, which can significantly improve the adsorption of carbon dioxide on the surface of the catalyst, enhance the electron transfer, and increase the reactivity of coal gasification.

[0085] High-resolution Fe 2p spectra show in Figure 4c that the Fe 2p 3 / 2 and Fe 2p 1 / 2 binding energies of the two spin-orbit doublets are 708.45 eV and 721.92 eV, respectively, and the binding energy distance between the two peaks is 13.47 eV. The peak at 708.31 eV is attributed to Fe 2+ . The peak at 709.72 eV is attributed to Fe 3+ . The appearance of Fe 2+ in the Ca2Fe2O5 sample reflects the presence of oxygen vacancies in the system. The generation of oxygen vacancies leaves two electrons for each missing oxygen atom, leading to the reduction of iron to Fe 2 + .

[0086] The high-resolution spectrum of Ca 2p is deconvoluted into four peaks Figure 4d ). The peaks at 346.73 eV and 350.34 eV correspond to Ca 2p 3 / 2 and Ca 2p 1 / 2 , respectively. The results show that there is Ca 2+ in the Ca2Fe2O5 catalyst. The other two peaks at 347.24 eV and 350.85 eV may be due to the residual CaCO3 / CaOx that may be left on the surface during the preparation process.

[0087] Thermogravimetric test was performed on the Ca2Fe2O5 catalyst, as shown in Figure 5 , the Ca2Fe2O5 catalyst hardly loses weight.

[0088] The Ca2Fe2O5 catalyst was characterized by Raman spectroscopy, as shown in Figure 14 , it can be seen from Figure 14 that the I D / I G of Ca2Fe2O5 in the Raman spectrum is greater than that of CaFeO3, and Ca2Fe2O5 has more oxygen vacancies.

[0089] Preparation Example 2 According to the method of Preparation Example 1, except that 900℃ high temperature calcination was replaced by 1000℃ high temperature calcination.

[0090] Preparation Example 3 According to the method of Preparation Example 1, except that 900℃ high temperature calcination is replaced by 1100℃ high temperature calcination.

[0091] Preparation Example 4 Ca2Fe2O5 was prepared by solid phase reaction method, CaCO3 and Fe2O3 were mixed and ground in a agate mortar for 5h, then heated to 1000℃ at a rate of 10℃ / min, kept at 1000℃ for 5h, and then cooled to room temperature in air.

[0092] Comparative Preparation Example 1 According to the method of Preparation Example 1, except that calcium acetate was not added, Fe3O4 catalyst was obtained.

[0093] Comparative Preparation Example 2 According to the method of Preparation Example 1, except that iron nitrate nonahydrate was not added, CaO catalyst was obtained.

[0094] Comparative Preparation Example 3 Iron nitrate nonahydrate and calcium nitrate pentahydrate were dissolved in deionized water in a ratio of 1:1 according to the stoichiometric ratio of metal cations, and the solution was stirred in a water bath at 70℃ for 30 minutes. After all the reagents were completely dissolved in water and dispersed, citric acid was added to the solution in a ratio of 3:1 according to the molar ratio of citric acid to the total cations in the solution. After the citric acid was completely dissolved in the solution, the amount of ethylene glycol added was twice the molar amount of citric acid. After adding the ethylene glycol, the temperature was raised to 80℃ and stirring was continued for 2 hours until the gel was formed. The precursor sample was placed in a muffle furnace and calcined at 400℃ for 2 hours to remove the organic matter in the sample. The temperature was then raised to 1100℃ and calcined for 6 hours to obtain CaFeO3 perovskite catalyst.

[0095] Thermogravimetric test was performed on the CaFeO3 catalyst, as shown in Figure 11b , there was about 47% weight loss and a weight loss rate of -9%·min -1 .

[0096] Raman characterization was performed on the CaFeO3 catalyst, as shown in Figure 14 , it can be seen from Figure 14 that the I D / I G of Ca2Fe2O5 in the Raman spectrum is greater than that of CaFeO3, so Ca2Fe2O5 has more defects.

[0097] The following examples are used to illustrate the method of coal catalytic gasification reaction in the present application.

[0098] Example 1 The coal was dried in a constant temperature drying oven at 100°C for 12h, then pickled with 6mol / L HCl in a water bath at 60°C for 4h, after reaction, washed with deionized water until neutral; then pickled with concentrated HF in a water bath at 60°C for 4h, after reaction, washed with deionized water until neutral, finally pickled with 6mol / L HCl in a water bath at 60°C for 4h, after reaction, washed with deionized water until neutral, and dried in a constant temperature drying oven at 80°C for 12h. About 5g of coal sample was placed in a tube furnace, and heated at a rate of 5°C / min under N2atmosphere, and calcined at 900°C for 30min to obtain coal char.

[0099] The coal catalytic gasification experiment was carried out on a simultaneous thermal analyzer, and the Ca2Fe2O5catalyst obtained in Preparation Example 1 was combined with the coal char obtained above by impregnation method (the mass ratio of catalyst to coal char was 1:8). First, the temperature was raised from room temperature to 900°C under Ar2atmosphere, and after constant temperature for 5min, the Ar2was switched to CO2, and the space velocity of CO2was 850h-1. When the reaction temperature reached 1400°C, the experiment was ended. -1

[0100] The TG and DTG curves of the gasification characteristics of the coal char catalyzed by the Ca2Fe2O5catalyst are shown in Figure 5 , and the experimental results are shown in Table 1.

[0101] Example 2 According to the method of Example 1, except that the mass ratio of catalyst to coal char was adjusted to 1:4, the TG and DTG curves of the gasification characteristics of the coal catalytic gasification reaction of the catalyst are shown in Figure 6 , and the experimental results are shown in Table 1.

[0102] Example 3 According to the method of Example 1, except that the mass ratio of catalyst to coal char was adjusted to 1:6, the TG and DTG curves of the gasification characteristics of the coal catalytic gasification reaction of the catalyst are shown in Figure 7 , and the experimental results are shown in Table 1.

[0103] Example 4 According to the method of Example 1, except that the mass ratio of catalyst to coal char was adjusted to 1:10, the TG and DTG curves of the gasification characteristics of the coal catalytic gasification reaction of the catalyst are shown in Figure 8 , and the experimental results are shown in Table 1.

[0104] Example 5 According to the method of Example 1, except that the catalyst obtained in Preparation Example 1 was replaced by an equal amount of catalyst obtained in Preparation Example 2. ​

[0105] The TG, DTG curves of the gasification characteristics of the catalyst during the coal catalytic gasification reaction are shown in Figure 9 The experimental results are shown in Table 1.

[0106] Example 6 The method of Example 1 was followed, except that the catalyst obtained in Preparation Example 1 was replaced with an equal amount of the catalyst obtained in Preparation Example 3.

[0107] The TG, DTG curves of the gasification characteristics of the catalyst during the coal catalytic gasification reaction are shown in Figure 10 The experimental results are shown in Table 1.

[0108] Example 7 The method of Example 1 was followed, except that the catalyst obtained in Preparation Example 1 was replaced with an equal amount of the Ca2Fe2O5 catalyst obtained in Preparation Example 4.

[0109] Comparative Example 1 The method of Example 1 was followed, except that the catalyst obtained in Preparation Example 1 was replaced with an equal amount of the catalyst obtained in Comparative Preparation Example 1.

[0110] The TG, DTG curves of the gasification characteristics of the catalyst during the coal catalytic gasification reaction are shown in Figure 12 The experimental results are shown in Table 1.

[0111] Comparative Example 2 The method of Example 1 was followed, except that the catalyst obtained in Preparation Example 1 was replaced with an equal amount of the catalyst obtained in Comparative Preparation Example 2.

[0112] The TG, DTG curves of the gasification characteristics of the catalyst during the coal catalytic gasification reaction are shown in Figure 13 The experimental results are shown in Table 1.

[0113] Comparative Example 3 The method of Example 1 was followed, except that the Ca2Fe2O5 catalyst obtained in Preparation Example 1 was not added to the coal catalytic gasification reaction.

[0114] The TG, DTG curves of the gasification characteristics of the coal coke are shown in Figure 5 The experimental results are shown in Table 1.

[0115] Comparative Example 4 The method of Example 1 was followed, except that the catalyst obtained in Preparation Example 1 was replaced with an equal amount of the CaFeO3 catalyst obtained in Comparative Preparation Example 3.

[0116] The TG, DTG curves of the gasification characteristics of the catalyst during the coal catalytic gasification reaction are shown in Figure 11a The experimental results are shown in Table 1.

[0117] Table 1

[0118] From the above results, it can be seen that the catalyst in the preparation example of the present application has stability in the reaction, and the example of the present application can be compared with the comparative example, and it can be seen that the catalyst prepared in the comparative example has lower activity than the present application. In the comparative example 4, although the maximum gasification rate is higher than that of example 1, the thermogravimetric test of the catalyst of CaFeO3 itself shows that there is about 47% weight loss and-9%·min -1 The stability is very poor in the coal gasification reaction. The addition of the catalyst prepared in the example of the present application can reduce the initial gasification temperature and the end gasification temperature of the coal catalytic gasification reaction, shorten the reaction time, accelerate the reaction rate, end the gasification reaction in advance, improve the efficiency of the coal catalytic gasification reaction, and has higher stability. The problems of slow coal catalytic gasification reaction rate and high gasification temperature are solved.

[0119] The preferred embodiments of the present application are described in detail above, but the present application is not limited thereto. Within the technical concept of the present application, various simple modifications can be made to the technical solutions of the present application, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be considered as disclosed by the present application and belong to the protection scope of the present application.

Claims

1. Use of a perovskite type catalyst in a catalytic gasification reaction of coal, characterized in that, The catalyst comprises a perovskite material of A2B2O5 type, wherein A site elements are Ca and / or Sr, and B site elements are at least one of Fe, Mn, Ni and Co.

2. The use according to claim 1, wherein, The size distribution of the particles of the catalyst is 50-350 nm, preferably 50-300 nm; And / or, the catalyst has a spherical morphology; And / or, the catalyst is characterized by XPS, and the content of oxygen vacancies in the catalyst is 20-30%, preferably 23-26%.

3. Use according to claim 1 or 2, wherein, The A site elements are Ca, and the B site elements are Fe; Preferably, the catalyst is prepared by a sol-gel-high temperature calcination coupling method.

4. Use according to claim 3, wherein, The preparation method of the catalyst comprises: (1) mixing A site element source, B site element source, chelating agent and crosslinking agent in the presence of a solvent to form a gel by reaction; (2) drying and calcining the gel.

5. Use according to claim 4, wherein, The molar ratio of the A site element source to the B site element source is 1:0.8-1.2 in terms of metal elements; And / or, the molar ratio of the chelating agent to the crosslinking agent is 1:0.8-1.2; And / or, the chelating agent is selected from citric acid and / or ethylenediaminetetraacetic acid; And / or, the crosslinking agent is selected from at least one of ethylene glycol, 1,4-butanediol and 1,6-hexanediol; And / or, the temperature is 80-90℃, and the mixing time is 2-5h; And / or, the drying conditions include a temperature of 100-150℃ and a time of 8-12h; And / or, the calcination is carried out in a first protective atmosphere; Preferably, the first protective atmosphere is selected from at least one of argon, helium and nitrogen; And / or, the calcination comprises low-temperature calcination followed by high-temperature calcination; Preferably, the temperature of the low-temperature calcination is 350-450℃, and the time is 2-5h; Preferably, the temperature of the high-temperature calcination is 850-950℃, and the time is 3-5h.

6. A method of catalytic gasification of coal, characterized by, The method comprises: contacting the catalyst, carbon-containing raw material and gasifying agent to perform coal catalytic gasification reaction; The catalyst comprises a perovskite material of A2B2O5 type, wherein A site elements are Ca and / or Sr, and B site elements are at least one of Fe, Mn, Ni and Co. The mass ratio of the catalyst to the carbon-containing raw material is 1:4-11.

7. The method of claim 6, wherein, The size distribution of the particles of the catalyst is 50-350 nm, preferably 50-300 nm; And / or, the catalyst has a spherical morphology; Preferably, the catalyst is characterized by XPS, and the content of oxygen vacancies in the catalyst is 20-30%, preferably 23-26%.

8. The method of claim 6 or 7, wherein, The method further comprises: loading the catalyst on the carbon-containing raw material, and then contacting with the gasifying agent; Preferably, the loading method is selected from at least one of impregnation method, dry mixing method and ion exchange method; And / or, the mass ratio of the catalyst to the carbon-containing raw material is 1:4-10; And / or, the carbon-containing raw material is selected from at least one of coal coke, lignite, bituminous coal, coke, semi-coke and petroleum coke, preferably coal coke; And / or, the gasifying agent is selected from at least one of carbon dioxide, liquid water and water vapor, preferably carbon dioxide; and / or the gasification agent has a space velocity of 750-900 h -1 , preferably 800-900 h -1 .

9. The method of any of claims 6-8, wherein, The coal catalytic gasification reaction is carried out in a second protective atmosphere; Preferably, the second protective atmosphere is selected from argon and / or nitrogen.

10. The method of any of claims 6-9, wherein, The initial gasification temperature of the catalytic gasification reaction of the coal is 900-1100°C, preferably 950-1000°C.

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