Ni-Fe binary metal coal catalytic gasification catalyst, and preparation method and application thereof

Abstract

This invention discloses a Ni-Fe binary metal coal catalytic gasification catalyst, its preparation method, and its applications, belonging to the field of coal gasification. This invention addresses the technical problem of Ni catalysts being prone to sintering and sulfur poisoning under high-temperature conditions, leading to a significant reduction in their activity. In this invention, Ni and Fe are anchored on HZSM5 molecular sieves through physical adsorption and are highly dispersed on the surface of the HZSM5 molecular sieves, prepared using an excess impregnation method and calcination. This invention couples the lateral etching characteristics of Ni and the vertical etching characteristics of Fe, enhancing the gasification etching process of coal by the catalyst in the spatial direction, significantly improving carbon conversion rate, and providing an optimized approach for the design of coal catalytic gasification catalysts. Compared with existing catalysts, the Ni-Fe binary metal catalyst exhibits superior catalytic activity and thermal stability, while its preparation method is simple, making it a coal catalytic gasification catalyst with great development potential.

Description

Technical Field

[0001] This invention belongs to the field of coal gasification technology, specifically, it relates to a Ni-Fe binary metal coal catalytic gasification catalyst, its preparation method, and its application. Background Technology

[0002] Coal gasification technology is a clean coal technology and a key core technology for the development of coal-based chemical synthesis (ammonia, methanol, acetic acid, olefins, etc.) and coal-based liquid fuel synthesis (dimethyl ether, gasoline, etc.), hydrogen production, integrated gasification combined cycle (IGCC) power generation, and gasification combined fuel cell (IGFC) power generation. Developing combined heat and power (CHP) technologies centered on coal gasification has become a hot technology and important development direction for the efficient and clean utilization of coal in various countries. The gasification process is a thermochemical process that, under high-temperature conditions, uses air, pure oxygen, steam, or hydrogen as the gasification medium to convert solid fuels into gaseous fuels through partial oxidation reactions. However, for traditional gasification technologies, the high reaction temperatures required and the generation of more low-reactivity graphitic carbon at high temperatures present bottlenecks in practical applications.

[0003] Catalytic gasification technology has been extensively studied in recent years due to its low reaction temperature and high thermal efficiency. Accelerating the decomposition of carbon-oxygen surface complexes with metal catalysts to increase the gasification reaction rate at relatively low temperatures has always been a hot topic in catalytic gasification research. Under gasification conditions, coal and char are converted into low-activity graphitic carbon, and the etching of graphitic carbon by metals is the essential process of catalytic gasification. Different metals exhibit differences in their lateral and vertical etching capabilities. From the morphological characteristics of the gasification etching trenches, some metals form deep trenches vertically on the graphitic carbon surface, but the trenches are relatively narrow; other metals leave shallower but wider trenches. Therefore, when using a single metal catalyst, there is still considerable room for improvement in its catalytic performance.

[0004] Ni catalyst is a commonly used catalytic catalyst for coal gasification. During catalytic gasification, it exhibits edge decay etching with lateral etching characteristics and shows high catalytic activity in coal catalytic gasification. However, Ni catalyst is prone to sintering and sulfur poisoning under high temperature conditions, which greatly reduces its activity and makes it difficult to promote in industry. Summary of the Invention

[0005] This invention provides a Ni-Fe binary metal coal catalytic gasification catalyst and its preparation method. The binary metal catalyst couples the lateral etching characteristics of metallic Ni and the vertical etching characteristics of metallic Fe. Their lateral widening ability and vertical penetration ability complement each other, which enhances the gasification etching process in the spatial direction and can form deep and wide etching trenches, thus greatly improving the carbon conversion rate.

[0006] Adding Fe to the Ni catalyst improves the dispersibility of the Ni phase particles and can suppress the sintering of the Ni catalyst at high temperatures. The catalyst of this invention uses HZSM5 molecular sieve with high acidity as a support, which enhances the Ni catalyst's resistance to sulfur poisoning. Simultaneously, HZSM5 molecular sieve has a large specific surface area, allowing for a large loading of active materials in the catalyst. Furthermore, it exhibits high thermal stability, high tolerance to sulfur and nitrogen compounds, and easy regeneration, making it an excellent support for Ni-Fe binary metal coal catalytic gasification catalysts.

[0007] The present invention adopts the following technical solution:

[0008] The purpose of this invention is to provide a Ni-Fe binary metal coal catalytic gasification catalyst, which is prepared by an excess impregnation method. In the catalyst, Ni and Fe are anchored on HZSM5 molecular sieves through physical adsorption and are highly dispersed on the surface of the molecular sieve. Specifically, Ni accounts for 15%-20% of the molecular sieve mass, and Fe accounts for 30%-40% of the molecular sieve mass.

[0009] This invention provides a method for preparing a Ni-Fe binary metal coal catalytic gasification catalyst, characterized by comprising the following steps:

[0010] Step 1: Dissolve Ni(NO3)2·6H2O and Fe(NO3)3·9H2O in deionized water to obtain a catalyst precursor solution;

[0011] Step 2: Calcine the HZSM5 molecular sieve and cool it to room temperature;

[0012] Step 3: The calcined HZSM5 molecular sieve is impregnated in the precursor solution using the excess impregnation method, while heating and stirring continuously, and then dried.

[0013] Step 4: Calcine again, grind and sieve to obtain the catalyst.

[0014] Further specifying, in step 2, calcination is carried out at 500℃-600℃ for 2-3 hours.

[0015] Further specifying, in step 3, the immersion temperature is 80°C.

[0016] To further specify, in step 3, the heating and stirring time is 1 hour.

[0017] Further specifying, in step 3, drying is performed at 110℃-120℃ for 10h-12h.

[0018] Further specifying, in step 4, the roasting is carried out at 500℃-600℃ for 3-4 hours.

[0019] To further specify, in step 4, the sample is passed through a 120-mesh sieve.

[0020] The catalyst described above or the catalyst prepared by any of the methods described above may be used for coal catalytic gasification.

[0021] Compared with the prior art, the present invention has the following advantages:

[0022] This invention provides a Ni-Fe binary metal coal catalytic gasification catalyst, its preparation method, and its applications. The Ni-Fe binary metal catalyst used in this invention, as a catalyst for coal catalytic gasification, has a simple preparation method and couples the lateral etching characteristics of Ni and the vertical etching characteristics of Fe during the catalytic gasification process, enhancing the gasification etching process in the spatial direction and significantly improving carbon conversion rate. This invention, from the perspective of the spatial directional characteristics of metal gasification etching, provides an optimization approach for the design of coal catalytic gasification catalysts.

[0023] The catalyst of this invention uses HZSM5 molecular sieve with a high specific surface area as a support, and selects Ni(NO3)2·6H2O and Fe(NO3)3·9H2O with good water solubility as precursors. An excess impregnation method is used to allow more Ni and Fe to be adsorbed on the surface of HZSM5 molecular sieve.

[0024] This invention utilizes HZSM5 molecular sieve with high acidity as a catalyst support, enhancing the resistance of Ni catalysts to sulfur poisoning, while Fe inhibits the sintering of Ni catalysts at high temperatures. This effectively solves the problems associated with Ni catalysts and significantly improves their catalytic performance.

[0025] To further understand the features and technical content of this invention, please refer to the following detailed description and accompanying drawings. However, the accompanying drawings are for reference and illustration only and are not intended to limit the invention. Attached Figure Description

[0026] Figure 1 The carbon conversion rate of coal gasification under different amounts of Ni-Fe binary metal coal catalytic gasification catalyst and single metal catalyst is shown. Detailed Implementation

[0027] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, while not limiting the invention in any way. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0028] Example 1: In this example, the Ni-Fe binary metal coal catalytic gasification catalyst was prepared according to the following steps:

[0029] (1) A catalyst precursor solution was prepared by fully dissolving 4.95 g of Ni(NO3)2·6H2O and 14.47 g of Fe(NO3)3·9H2O in 100 mL of deionized water;

[0030] (2) Take 8.13g of HZSM5 molecular sieve and calcine it at 550℃ for 3h. After the temperature drops to room temperature, it is ready for use.

[0031] (3) 5.01g of calcined HZSM5 molecular sieve was placed in the precursor solution, stirred continuously at 80℃ for 1h, and then dried at 110℃ for 12h.

[0032] (4) The dried material was calcined at 550℃ for 3 hours, and after cooling to room temperature, it was ground and sieved to obtain particles with a particle size of less than 120 mesh, which is the Ni-Fe binary metal coal catalytic gasification catalyst, in which Ni accounts for 20% of the molecular sieve mass and Fe accounts for 40% of the molecular sieve mass. The yield of the catalyst was calculated to be 83.2% by weighing.

[0033] Example 2: In this example, the Ni-Fe binary metal coal catalytic gasification catalyst was prepared according to the following steps:

[0034] (1) A catalyst precursor solution was prepared by dissolving 4.90 g of Ni(NO3)2·6H2O and 14.42 g of Fe(NO3)3·9H2O in 100 mL of deionized water.

[0035] (2) Take 8.01g of HZSM5 molecular sieve and calcine it at 550℃ for 3h. After the temperature drops to room temperature, it is ready for use.

[0036] (3) 4.99g of calcined HZSM5 molecular sieve was placed in the precursor solution, stirred continuously at 80℃ for 1h, and then dried at 110℃ for 12h.

[0037] (4) The dried material was calcined at 550℃ for 3 hours, and after cooling to room temperature, it was ground and sieved to obtain particles with a particle size of less than 120 mesh, which is the Ni-Fe binary metal coal catalytic gasification catalyst, in which Ni accounts for 20% of the molecular sieve mass and Fe accounts for 40% of the molecular sieve mass. The yield of the catalyst was calculated to be 80.8% by weighing.

[0038] Example 3: In this example, the Ni-Fe binary metal coal catalytic gasification catalyst was prepared according to the following steps:

[0039] (1) A catalyst precursor solution was prepared by dissolving 4.96 g of Ni(NO3)2·6H2O and 14.48 g of Fe(NO3)3·9H2O in 100 mL of deionized water.

[0040] (2) Take 8.09g of HZSM5 molecular sieve and calcine it at 550℃ for 3h. After the temperature drops to room temperature, it is ready for use.

[0041] (3) 5.01g of calcined HZSM5 molecular sieve was placed in the precursor solution, stirred continuously at 80℃ for 1h, and then dried at 110℃ for 12h.

[0042] (4) The dried material was calcined at 550℃ for 3 hours, and after cooling to room temperature, it was ground and sieved to obtain particles with a particle size of less than 120 mesh, which is the Ni-Fe binary metal coal catalytic gasification catalyst, in which Ni accounts for 20% of the molecular sieve mass and Fe accounts for 40% of the molecular sieve mass. The yield of the catalyst was calculated to be 82.1% by weighing.

[0043] Catalyst performance evaluation

[0044] Taking bituminous coal as an example, the Ni-Fe binary metal coal catalytic gasification catalyst prepared in Example 1 above, and the Fe and Ni monometallic coal catalytic gasification catalyst prepared by the same method, were added to coal at different mass percentages, and their performance was tested on a fluidized bed test apparatus. Evaluation conditions: gasification temperature 900℃, CO2 flow rate of gasifying agent 1.8 L / min. The carbon conversion rate of coal catalytic gasification with different catalyst addition amounts is shown below. Figure 1 As shown, the carbon conversion rate of coal catalytic gasification gradually increases with the increase of catalyst addition. Furthermore, the catalytic effect of the Ni-Fe binary metal coal catalytic gasification catalyst is far superior to that of Fe and Ni monometallic coal catalytic gasification catalysts. After adding 20% ​​Ni-Fe binary metal coal catalytic gasification catalyst, the carbon conversion rate increased from 10.1% to 85.1%, indicating that this Ni-Fe binary metal coal catalytic gasification catalyst has excellent catalytic performance. This invention uses bituminous coal as an example to test catalyst performance, but testing with other coal types can also improve the carbon conversion rate, although the increase may differ slightly.

Claims

1. The application of a Ni-Fe binary metal catalyst in coal gasification, characterized in that, In the catalyst, Ni and Fe are physically adsorbed and anchored on the HZSM5 molecular sieve and highly dispersed on the surface of the HZSM5 molecular sieve, wherein Ni accounts for 15%-20% of the mass of the HZSM5 molecular sieve and Fe accounts for 30%-40% of the mass of the HZSM5 molecular sieve; it is prepared according to the following steps: Step 1: Dissolve Ni(NO3)2·6H2O and Fe(NO3)3·9H2O in deionized water to obtain a precursor solution; Step 2: Calcine the HZSM5 molecular sieve and cool it to room temperature; Step 3: The calcined HZSM5 molecular sieve is impregnated in the precursor solution using the excess impregnation method, while heating and stirring continuously, and then dried. Step 4: Calcine again, grind and sieve to obtain the catalyst; In step 2, calcination is carried out at 500 ℃-600 ℃ for 2 h-3 h.

2. The application according to claim 1, characterized in that, In step 3, the immersion temperature is 80 ℃ and the time is 1 h.

3. The application according to claim 1, characterized in that, In step 3, dry at 110 ℃-120 ℃ for 12 h.

4. The application according to claim 1, characterized in that, In step 4, calcination is carried out at 500 ℃-600 ℃ for 3 h-4 h.

5. The application according to claim 1, characterized in that, In step 4, the sample is passed through a 120-mesh sieve.

Images