A kind of composite catalyst and preparation method thereof

A catalyst and composite technology, applied in chemical instruments and methods, catalysts for physical/chemical processes, preparation/purification of sulfur, etc. The effects of absorption and decomposition, controllable process parameters, and improved stability

Active Publication Date: 2022-02-22
XIANGTAN UNIV
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  • Abstract
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Problems solved by technology

[0003] At present, the main method for industrially treating hydrogen sulfide waste gas is the Claus process, which is to incompletely oxidize hydrogen sulfide to generate water and sulfur, so that sulfur can be recovered, but hydrogen resources are wasted, because hydrogen sulfide waste gas cannot be recovered It is completely oxidized, and the tail gas is also accompanied by the generation of sulfur dioxide. Direct discharge into the atmosphere will cause secondary pollution. Therefore, it is very meaningful to find an effective way to directly decompose hydrogen sulfide into sulfur and hydrogen.
[0004] In recent years, there are many shortcomings in the method of directly decomposing hydrogen sulfide to generate hydrogen and sulfur: excessive energy consumption, expensive materials, low catalyst decomposition efficiency and easy deactivation, harsh decomposition reaction conditions, etc., for example: Furhad et al. Directly decompose hydrogen sulfide without adding a catalyst. It is found that the conversion rate of hydrogen sulfide is 35.6% at a temperature of 1200°C and a pressure of 0.1Mpa. The rate can reach 65.8%. Although this process realizes the direct decomposition of hydrogen sulfide, the required temperature is too high and consumes a lot of energy; Zhao et al. used pulsed corona discharge plasma reactor to explore the direct decomposition of hydrogen The minimum energy consumption of each hydrogen sulfide molecule is 17 eV, but it cannot handle the high concentration of hydrogen sulfide gas, which also limits the industrial application; Ma Guijun et al. 2+ When doped into ZnS, the decomposition rate of hydrogen sulfide can reach 17 μmol / h, but the catalyst is easily deactivated, the utilization rate of visible light is extremely low, and the decomposition efficiency is not high

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  • A kind of composite catalyst and preparation method thereof
  • A kind of composite catalyst and preparation method thereof
  • A kind of composite catalyst and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0021] The specific steps of alkali treatment of silicon carbide: put silicon carbide into an alkali solution of a certain concentration, the treatment temperature is 50-90°C, and the treatment time is 1-6 hours; the alkali solution is sodium hydroxide or potassium hydroxide solution At least one of them, the molar concentration of the alkali solution is 0.2-4 mol / L.

[0022] A kind of preparation method of composite catalyst:

[0023] Step 1: Weigh 0.276g of ammonium molybdate and 0.800g of cobalt nitrate hexahydrate into a beaker, add 40ml of pure water, and stir to dissolve.

[0024] In the second step, 2 g of alkali-treated silicon carbide is weighed and added to the solution in the first step, and stirred on a magnetic stirrer to form a mixed solution.

[0025] The third step is to put the mixed liquid into a constant temperature water bath, firstly age it at 40°C for 30 minutes, then evaporate it at 70°C for 4 hours, and then put it into an oven and dry it at a constant...

Embodiment 2

[0033] The composite microwave catalyst prepared according to Example 1 is applied to the decomposition of catalytic hydrogen sulfide, specifically: first, asbestos is filled in the reaction quartz tube of the microwave reactor to facilitate fixing the catalyst bed, and then the prepared in Example 1 The composite catalyst is placed in a quartz tube to form a microwave catalyst bed, a thermocouple is inserted into the center of the catalyst bed, and then a mixed gas of hydrogen sulfide is introduced to cause a gas-solid phase catalytic reaction to achieve the purpose of decomposing hydrogen sulfide.

[0034] The mixed gas is provided by Dalian Date Gas Co., Ltd., and consists of nitrogen and hydrogen sulfide, wherein the hydrogen sulfide content is 15vol%.

[0035] The gas chromatograph was GC-7890A manufactured by Agilent Corporation, USA.

[0036]The range of microwave power is 0-1350W, preferably 300-800W, and the frequency is 2450MHz.

[0037] Details are as follows:

[...

Embodiment 3

[0043] In this example, different kinds of composite catalysts were selected to carry out the hydrogen sulfide decomposition reaction experiment. The dosage of the composite catalyst was 2 g, the mesh size was 40-60 mesh, and the bed temperature of the catalyst was 650°C. The carbonization time was all 1 hour. Hydrogen sulfide mixed gas (use 15vol% H in the present invention 2 S and 85vol% N 2 The mixed gas was tested) the inlet flow rate was 60ml / min, the reaction pressure was normal pressure, and the temperature of the reaction bed was regulated by adjusting the microwave power. The experimental results are shown in Table 2. Table 2 shows the decomposition rate of different catalysts for microwave catalytic decomposition of hydrogen sulfide.

[0044] Table 2

[0045] catalyst Bed temperature (°C) Hydrogen sulfide decomposition rate (%) C-Mo 2 C / SiC

[0046] C-Mo 2 C / SiC, C-Co 2 The decomposition rates of C / SiC and C-WC / SiC catalysts were 50.1%, 49.5...

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Abstract

A composite catalyst and a preparation method thereof, the catalyst includes at least one carbon-composite transition metal carbide as an active component and silicon carbide as a carrier, when M represents the transition metal, MC is a transition metal carbide, The composite catalyst is represented as C-MC / SiC. The preparation method is as follows: first dissolve the transition metal salt to form a transition metal salt solution, and then mix it with silicon carbide; then evaporate the mixed solution to dryness, dry, and calcinate to obtain the precursor; finally, the precursor is in the reactor, microwave, carbonized, and cooled A composite catalyst is obtained. The invention can not only maximize the catalytic performance of the active components, but also greatly improve the stability of the catalyst, and contribute to the decomposition of hydrogen sulfide; alkali treatment of silicon carbide is more conducive to the absorption of hydrogen sulfide and break down. The raw materials of the catalyst are low in cost and easy to obtain, and the preparation method has simple steps, controllable process parameters and convenient operation.

Description

technical field [0001] The invention belongs to the technical field of catalysts, and in particular relates to a composite catalyst and a preparation method thereof. Background technique [0002] With the rapid development of society and economy in today's society, the country and the people pay more and more attention to environmental protection. Hydrogen sulfide is a by-product in the mining and processing of coal, oil and natural gas. If it is directly discharged into the environment without treatment, it will cause serious environmental pollution. Especially in recent years, gas fields with relatively high sulfur content have emerged continuously. In the petrochemical industry, hydrodesulfurization technology is widely used to produce high-quality fuel oil. Therefore, a large amount of hydrogen sulfide waste gas is produced every day. Corrosion of equipment and piping during transport. Hydrogen sulfide is a highly toxic gas with high chemical activity. When the concentr...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B01J27/224C01B17/04
Inventor 徐文涛陈佳楠周继承朱俊
Owner XIANGTAN UNIV
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