Calcium-based aerogel desulfurization catalyst and preparation method thereof

Abstract

The present application relates to desulfurization catalyst technical field, specifically to a kind of calcium-based aerogel desulfurization catalyst and its preparation method.The raw materials include the following share:high specific surface calcium hydroxide 70-90 parts, oxide aerogel 2-20 parts, gasification slag 0.5-10 parts, carbide slag 0.5-10 parts.Preparation method specifically: the above raw materials are added into ball mill respectively to be dispersed, the obtained uniformly dispersed mixture is obtained D90 greater than 200 mesh, the dry powder with bulk density less than 0.5g / cm 3 , i.e., calcium-based aerogel desulfurization catalyst;The preparation process of the method is simple, raw material is economically available, the obtained catalyst particle is uniformly dispersed, the bulk density is small, the specific surface area is high, can be high-efficiency desulfurization under low temperature condition, can be widely applied to industrial flue gas purification desulfurization industry.

Description

Technical Field

[0001] This invention relates to the field of desulfurization catalyst technology, specifically to a calcium-based aerogel desulfurization catalyst and its preparation method. Background Technology

[0002] To reduce SO2 emissions from industrial flue gas, researchers have developed a series of effective desulfurization catalysts and devices.

[0003] Based on whether water is added during the desulfurization process and the dry / wet state of the desulfurization products, desulfurization processes are divided into three main categories: wet, semi-dry, and fully dry. Wet desulfurization is a relatively mature process with a low calcium-to-sulfur ratio (1.1–1.2) and high desulfurization efficiency, but it suffers from large footprint, equipment susceptibility to corrosion, scaling, and clogging, and secondary pollution issues. Semi-dry desulfurization uses ordinary slaked lime (Ca(OH)2) as a desulfurizing agent. The calcium sulfate and calcium sulfite particles formed after reacting with SO2 are relatively large, easily clogging the pores of calcium hydroxide and hindering the absorption of sulfur dioxide from the flue gas, resulting in low desulfurization efficiency and low utilization efficiency of the desulfurizing agent. Dry desulfurization processes require less equipment investment and are simpler to operate. Currently, sodium bicarbonate is the main desulfurizing agent used in industrial production. Using ultrafine sodium bicarbonate powder as a desulfurizing agent, it decomposes under high-temperature flue gas to produce highly active sodium carbonate (Na2CO3), which reacts chemically with SO2 and other acidic media in the flue gas, being absorbed and purified to meet emission standards. However, baking soda is expensive and its desulfurization products are difficult to process.

[0004] High-specific-surface-area calcium hydroxide possesses well-developed pores, enabling rapid adsorption and absorption of HCl and SO2 in flue gas, achieving a utilization rate exceeding 85%. This addresses the issues of low efficiency and low utilization rate in sulfur dioxide removal associated with ordinary calcium hydroxide. CN115073023A discloses a method for preparing highly efficient desulfurization quicklime. By adding a pre-digester, the contact time between the digestion water and quicklime is increased. Adding hydrophilic organic surfactants and alkali metal compounds to the digestion water results in a quicklime product with small particle size, high specific surface area, and high reactivity, leading to higher desulfurization efficiency. CN210495909U obtains ultrafine powder particles by directly installing a superheated steam flow pulverizer at the desulfurization tower inlet, increasing the particle reaction surface area and enhancing the activity of the desulfurizing agent. Summary of the Invention

[0005] The purpose of this invention is to provide a calcium-based aerogel desulfurization catalyst and its preparation method. By adding oxide aerogel and ball milling and mixing, the particle size and packing density of the catalyst can be controlled, the specific surface area can be increased, the utilization rate of calcium hydroxide can be improved, and efficient desulfurization of industrial flue gas can be achieved.

[0006] To achieve the above objectives, the present invention employs the following technical solutions:

[0007] A calcium-based aerogel desulfurization catalyst, by weight, comprises 70-90 parts of high specific surface area calcium hydroxide, 2-20 parts of oxide aerogel, 0.5-10 parts of gasification slag, and 0.5-10 parts of carbide slag.

[0008] Furthermore, by weight, it includes 80-90 parts of high specific surface area calcium hydroxide, 5-10 parts of oxide aerogel, 0.5-5 parts of gasification slag, and 0.5-5 parts of carbide slag.

[0009] Furthermore, the specific surface area of ​​the high specific surface area calcium hydroxide is 30-100 m². 3 / g.

[0010] Furthermore, the oxide aerogel is one or both of silica aerogel and zinc oxide aerogel.

[0011] A method for preparing a calcium-based aerogel desulfurization catalyst includes the following steps:

[0012] (1) Weigh the high specific surface area calcium hydroxide, oxide aerogel, gasification slag and carbide slag according to the weight parts and add them to the ball mill for grinding and dispersing for a period of time to obtain a uniformly dispersed mixture;

[0013] (2) The uniformly dispersed mixture obtained in step (1) is separated by cyclone separation to obtain a D90 greater than 200 mesh and a bulk density less than 0.5 g / cm³. 3 The dry powder, namely calcium-based aerogel desulfurization catalyst.

[0014] Furthermore, the grinding and dispersion time is 1-5 hours.

[0015] Compared with the prior art, the present invention has the following advantages:

[0016] (1) The calcium-based aerogel desulfurization catalyst provided by the present invention uses calcium hydroxide with high specific surface area as active component. The high specific surface area and suitable pore size can improve the adsorption and reaction efficiency of SO2 in flue gas, thereby improving the desulfurization efficiency.

[0017] (2) The present invention uses oxide aerogel as an additive. Its porous structure and light weight and low density help to increase the specific surface area and effective pore volume of the desulfurizer, and play a positive role in promoting the adsorption and activation of SO2.

[0018] (3) In this invention, the mixture is ground and dispersed by a ball mill, and then separated by cyclone separation to obtain a desulfurizing agent mixture with uniform particle dispersion and low bulk density, which can increase the surface area of ​​the reaction particles and is beneficial to improving the desulfurization efficiency.

[0019] (4) The calcium-based aerogel desulfurization catalyst provided by the present invention has a simple preparation process, and the raw materials and equipment are economical and readily available. It can effectively reduce production costs and pollutant generation, and is energy-saving and environmentally friendly. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the present invention clearer, the following will describe them in conjunction with embodiments of the present invention.

[0021] The technical solutions of the present invention will be clearly and completely described. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0022] Example 1

[0023] The raw material composition of the calcium-based aerogel desulfurization catalyst is: high specific surface area calcium hydroxide (specific surface area of ​​30 m²). 3 90g of (g), 10g of silica aerogel, 3g of gasification furnace slag, and 3g of carbide slag.

[0024] Preparation method of calcium-based aerogel desulfurization catalyst: The above raw materials were added to a ball mill and ground and dispersed for 5 hours to obtain a uniformly dispersed mixture; the uniformly dispersed mixture was separated by cyclone separation to obtain a D90 of approximately 400 mesh and a bulk density of 0.4 g / cm³. 3 The dry powder is the calcium-based aerogel desulfurization catalyst, and the performance results are shown in Table 1.

[0025] Example 2

[0026] The raw material composition of the calcium-based aerogel desulfurization catalyst is: high specific surface area calcium hydroxide (specific surface area of ​​50 m²). 3 80g (g), 5g silica aerogel, 5g zinc oxide aerogel, 3g gasification slag, 3g calcium carbide slag.

[0027] Preparation method of calcium-based aerogel desulfurization catalyst: The above raw materials are added to a ball mill and ground and dispersed for 1.5 hours to obtain a uniformly dispersed mixture; the uniformly dispersed mixture is separated by cyclone separation to obtain a D90 of approximately 350 mesh and a bulk density of 0.45 g / cm³. 3 The dry powder is the calcium-based aerogel desulfurization catalyst, and the performance results are shown in Table 1.

[0028] Example 3

[0029] The raw material composition of the calcium-based aerogel desulfurization catalyst is: high specific surface area calcium hydroxide (specific surface area of ​​80 m²). 3 80g (g), 20g zinc oxide aerogel, 3g gasification slag, 3g calcium carbide slag.

[0030] Preparation method of calcium-based aerogel desulfurization catalyst: The above raw materials were added to a ball mill and ground and dispersed for 3 hours to obtain a uniformly dispersed mixture; the uniformly dispersed mixture was separated by cyclone separation to obtain a D90 of approximately 375 mesh and a bulk density of 0.42 g / cm³. 3 The dry powder is the calcium-based aerogel desulfurization catalyst, and the performance results are shown in Table 1.

[0031] Example 4

[0032] The raw material composition of the calcium-based aerogel desulfurization catalyst is: high specific surface area calcium hydroxide (specific surface area of ​​60 m²). 3 70g of silica aerogel, 10g of zinc oxide aerogel, 5g of gasification slag, and 3g of calcium carbide slag.

[0033] Preparation method of calcium-based aerogel desulfurization catalyst: The above raw materials were added to a ball mill and ground and dispersed for 2 hours to obtain a uniformly dispersed mixture; the uniformly dispersed mixture was separated by cyclone separation to obtain a D90 of approximately 325 mesh and a bulk density of 0.35 g / cm³. 3 The dry powder is calcium-based aerogel for desulfurization, and the performance results are shown in Table 1.

[0034] Example 5

[0035] The raw material composition of the calcium-based aerogel desulfurization catalyst is: high specific surface area calcium hydroxide (specific surface area of ​​90 m²). 3 90g of silica aerogel, 5g of zinc oxide aerogel, 10g of gasification slag, and 10g of calcium carbide slag.

[0036] Preparation method of calcium-based aerogel desulfurization catalyst: The above raw materials were added to a ball mill and ground and dispersed for 1.5 hours to obtain a uniformly dispersed mixture; the uniformly dispersed mixture was separated by cyclone separation to obtain a D90 of approximately 400 mesh and a bulk density of 0.38 g / cm³. 3 The dry powder is the calcium-based aerogel desulfurization catalyst, and the performance results are shown in Table 1.

[0037] Example 6

[0038] The raw material composition of the calcium-based aerogel desulfurization catalyst is: high specific surface area calcium hydroxide (specific surface area of ​​100 m²). 3 80g of silica aerogel, 5g of zinc oxide aerogel, 10g of gasification slag, and 3g of calcium carbide slag.

[0039] Preparation method of calcium-based aerogel desulfurization catalyst: The above raw materials were added to a ball mill and ground and dispersed for 3 hours to obtain a uniformly dispersed mixture; the uniformly dispersed mixture was separated by cyclone separation to obtain a D90 of approximately 375 mesh and a bulk density of 0.43 g / cm³. 3The dry powder is the calcium-based aerogel desulfurization catalyst, and the performance results are shown in Table 1.

[0040] Comparative Example 1

[0041] Raw material composition: High specific surface area calcium hydroxide (specific surface area of ​​30m²) 3 90g of gasification furnace slag, 10g of calcium carbide slag.

[0042] Preparation method: The above raw materials were added to a ball mill and ground and dispersed for 1.5 hours to obtain a uniformly dispersed mixture; the uniformly dispersed mixture was then separated by cyclone separator to obtain a D90 of approximately 300 mesh and a bulk density of 0.56 g / cm³. 3 The performance results of the dry powder are shown in Table 1.

[0043] Comparative Example 2

[0044] Raw material composition: 80g ordinary calcium hydroxide, 5g silica aerogel, 10g zinc oxide aerogel, 3g gasification furnace slag, 10g calcium carbide slag.

[0045] Preparation method: The above raw materials were added to a ball mill and ground and dispersed for 3 hours to obtain a uniformly dispersed mixture; the uniformly dispersed mixture was then separated by cyclone separation to obtain a D90 of approximately 250 mesh and a bulk density of 0.52 g / cm³. 3 The performance results of the dry powder are shown in Table 1.

[0046] Comparative Example 3

[0047] Raw material composition: 80g ordinary calcium hydroxide, 10g gasification furnace slag, 10g carbide slag.

[0048] Preparation method: The above raw materials were added to a ball mill and ground and dispersed for 1.5 hours to obtain a uniformly dispersed mixture; the uniformly dispersed mixture was then separated by cyclone separator to obtain a D90 of approximately 200 mesh and a bulk density of 0.63 g / cm³. 3 The performance results of the dry powder are shown in Table 1.

[0049] The performance of each comparative example and embodiment of the present invention was tested, and the performance indicators of the flue gas desulfurizer were: specific surface area, particle size, adsorption pore volume, and desulfurization efficiency.

[0050] The particle size and particle size distribution of the products in the examples and comparative examples were tested using a laser particle size analyzer.

[0051] The BET specific surface area and total pore volume of the products in the examples and comparative examples were tested and analyzed using a specific surface area analyzer according to the method in GB / T 19587-2017 "Determination of Specific Surface Area of ​​Solid Substances by Gas Adsorption BET Method".

[0052] For a direct comparison, the desulfurization performance tests were all conducted using exhaust gas (220℃) from a steel plant.

[0053] Table 1 Performance testing of calcium-based aerogel desulfurization catalysts

[0054]

[0055]

[0056] As shown in Table 1, the desulfurizer provided by this invention has the characteristics of large specific surface area, low bulk density, and large adsorption volume, exhibiting excellent desulfurization efficiency. The examples and comparative examples demonstrate that the use of high specific surface area calcium hydroxide and oxide aerogel is crucial for obtaining a high-performance desulfurizer; Examples 4 and 5 and Comparative Example 1 further illustrate that the type and amount of oxide aerogel added have a significant impact on the bulk density, adsorption volume, and desulfurizer performance. Comparative Examples 2 and 3 show that the influence of high specific surface area calcium hydroxide on desulfurization performance is also critical.

[0057] Contents not described in detail in this specification are prior art known to those skilled in the art. Although illustrative specific embodiments of the invention have been described above to facilitate understanding by those skilled in the art, it should be understood that the invention is not limited to the scope of the specific embodiments. Various modifications are readily apparent to those skilled in the art as long as they fall within the spirit and scope of the invention as defined and determined by the appended claims, and all inventions utilizing the concept of this invention are protected.

Claims

1. The application of a calcium-based aerogel desulfurization catalyst in flue gas desulfurization, characterized in that, By weight, the calcium-based aerogel desulfurization catalyst comprises 70-90 parts of high specific surface area calcium hydroxide, 2-20 parts of oxide aerogel, 0.5-10 parts of gasification slag, and 0.5-10 parts of carbide slag. The specific surface area of ​​the high specific surface area calcium hydroxide is 30-100 m². 2 / g; The oxide aerogel is one or both of silica aerogel and zinc oxide aerogel.

2. The application according to claim 1, characterized in that, By weight, the calcium-based aerogel desulfurization catalyst comprises 80-90 parts of high specific surface area calcium hydroxide, 5-10 parts of oxide aerogel, 0.5-5 parts of gasification slag, and 0.5-5 parts of carbide slag.

3. The application according to claim 1, characterized in that, The preparation method of the calcium-based aerogel desulfurization catalyst includes the following steps: (1) Weigh the high specific surface area calcium hydroxide, oxide aerogel, gasification slag and carbide slag according to the weight parts and add them to the ball mill for grinding and dispersing for a period of time to obtain a uniformly dispersed mixture; (2) The uniformly dispersed mixture obtained in step (1) is separated by cyclone separation to obtain a D90 greater than 200 mesh and a bulk density less than 0.5 g / cm³. 3 The dry powder, namely calcium-based aerogel desulfurization catalyst.

4. The application according to claim 3, characterized in that, The grinding and dispersion time is 1-5 hours.

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