Zinc oxide desulfurizer for high-precision desulfurization of coal gas and preparation method of zinc oxide desulfurizer

Abstract

The invention provides a zinc oxide desulfurizer for high-precision desulfurization of coal gas and a preparation method of the zinc oxide desulfurizer, and belongs to the technical field of coal gas desulfurization. The preparation method of the zinc oxide desulfurizer for high-precision desulfurization of the coal gas comprises the following steps: S1, mixing zinc oxide powder, an auxiliary agent and water according to a certain proportion to prepare pug; s2, carrying out extrusion molding on the pug obtained in the step S1 to obtain a desulfurizer precursor; and S3, drying and roasting the desulfurizer precursor obtained in the step S2 to obtain the zinc oxide desulfurizer. The auxiliary agent comprises any one or more of a forming agent, a pore forming agent and a synergist. The zinc oxide desulfurizer for high-precision desulfurization of coal gas is prepared by the preparation method. The zinc oxide desulfurizer provided by the invention has higher adsorption capacity for hydrogen sulfide in coal gas, the adsorption capacity can reach 35-40% at 300 DEG C, the sulfur release phenomenon hardly exists, the adsorption performance is more stable than that of the conventional desulfurizer, and the adsorption process is more environment-friendly.

Description

Technical Field

[0001] The invention relates to the technical field of coal gas desulfurization, and in particular to a zinc oxide desulfurizer used for high-precision desulfurization of coal gas and a preparation method thereof. Background Art

[0003] At present, the removal of hydrogen sulfide in coal gas is mainly wet desulfurization and dry desulfurization. Among them, wet desulfurization has the problem of low desulfurization efficiency and cannot meet the process requirements; while dry desulfurization mainly uses iron oxide desulfurizer and zinc oxide desulfurizer. Among them, iron oxide desulfurizer has a significant effect on the adsorption of hydrogen sulfide, but its desulfurization accuracy is low. After iron oxide treatment, the concentration of hydrogen sulfide in coal gas is 10-50ppm, which cannot meet the requirement of hydrogen sulfide concentration ≤0.1ppm required for clean catalytic conversion of coal gas; zinc oxide desulfurizer has good desulfurization effect, and the outlet hydrogen sulfide concentration can achieve the requirement of ≤0.1ppm, but conventional zinc oxide desulfurizer has low hydrogen sulfide adsorption capacity, short service life and sulfur release problem (hydrogen sulfide adsorption is unstable and hydrogen sulfide is released), which leads to unstable coal gas clean utilization process and abnormal process shutdown. Therefore, seeking a high-precision zinc oxide desulfurizer with large hydrogen sulfide adsorption capacity and the ability to solve the sulfur release problem is of great significance to the clean utilization of coal resources.

[0004] In view of this, the present invention is proposed. Summary of the invention

[0005] The object of the present invention is to provide a zinc oxide desulfurizer for high-precision desulfurization of coal gas and a preparation method thereof to solve the above problems.

[0006] In order to achieve the above objectives, the present invention particularly adopts the following technical solutions:

[0007] The present invention provides a method for preparing a zinc oxide desulfurizer for high-precision desulfurization of coal gas, the preparation method comprising the following steps:

[0008] S1: Mix zinc oxide powder, additives and water in a certain proportion to prepare a slurry;

[0009] S2: Extruding the mud obtained in S1 to obtain a desulfurizer precursor;

[0010] S3: drying and calcining the desulfurizing agent precursor obtained in S2 to obtain the zinc oxide desulfurizing agent;

[0011] The auxiliary agent includes: any one or more of a molding agent, a pore-forming agent, and a synergist; the molding agent is selected from any one or more of hydroxypropyl methylcellulose, carboxymethyl cellulose, and hydroxyethyl cellulose; the pore-forming agent includes basic zinc carbonate; the synergist includes ammonium chloride; and the water is deionized water.

[0012] In the present invention, the purity of the zinc oxide powder is ≥95%; preferably, the specific surface area of ​​the zinc oxide powder is ≥40m2 / g; preferably, the pore volume of the zinc oxide powder is ≥0.3cc / g; preferably, the sulfate impurity content in the zinc oxide powder is ≤0.5%.

[0013] Preferably, the certain proportion in S1 includes: in terms of mass fractions, the molding agent accounts for 1% to 3% of the mass of the zinc oxide powder; the pore-forming agent accounts for 10% to 15% of the mass of the zinc oxide powder; the synergist accounts for 15% to 20% of the mass of the zinc oxide powder; and the water accounts for 25% to 33% of the mass of the zinc oxide powder.

[0014] Preferably, the mixing time is 2 to 2.5 hours, and more preferably 2 hours.

[0015] Optionally, after step S1 and before step S2, the method further includes: curing the mud obtained in step S1;

[0016] Preferably, the curing treatment conditions are: maintaining an ambient temperature of 50 to 80° C., an ambient humidity of 60% to 90%, and curing treatment for 10 to 12 hours.

[0017] Preferably, the drying temperature is 120°C for 3-4 hours; and the calcining temperature is 120-330°C.

[0018] Further preferably, the calcination is enhanced calcination; the enhanced calcination comprises a first stage calcination and a second stage calcination performed sequentially:

[0019] The first stage calcination comprises: heating the dried desulfurization agent precursor from 120° C. to 200° C. at a heating rate of 2° C. / min in a mixed atmosphere of nitrogen and carbon dioxide, and staying at 200° C. for 7 hours;

[0020] The second stage roasting includes: first, gradually replacing the mixed atmosphere of the first stage roasting with hot air at 200-205°C; when the oxygen content of the atmosphere in the roasting system reaches 20% and the carbon dioxide concentration is lower than 0.1%, starting to heat up at 5°C / min, roasting for 5 hours after reaching the target temperature of 330°C, and waiting to cool to room temperature to obtain the zinc oxide desulfurizer for high-precision desulfurization of coal gas.

[0021] More preferably, in the first stage of roasting, the mixed atmosphere circulates only inside the roasting system and does not exchange heat or components with the outside;

[0022] The concentration of carbon dioxide in the mixed atmosphere is 60% to 85%, the concentration of nitrogen is 15% to 40%, and the oxygen content is required to be ≤0.1%.

[0023] The first stage of the present invention is a calcination atmosphere of nitrogen and carbon dioxide. By introducing carbon dioxide into the calcination system, the active component ZnO in the zinc oxide desulfurizer absorbs the carbon dioxide in the calcination atmosphere and forms a three-effect composite ZnO-NH3-CO2 (PKa=28.9) with the synergist ammonium chloride in the formula. The three-effect composite is a solid super base, and its alkalinity is much greater than that of conventional zinc oxide products (the main components of conventional zinc oxide desulfurizers are: ZnO (PKa=5.2), MnO (PKa=9.3) or Fe2O3 (PKa=7.5). It has an extremely high reaction rate with acidic hydrogen sulfide in coal gas, and the formed product ZnS-NH3-CO2 is 1.5 times the reaction temperature of the conventional zinc oxide desulfurizer. O2 (PKa = 26.1) is still a solid super base, which can continuously react with the acidic hydrogen sulfide in the coal gas, thus avoiding various problems existing in conventional zinc oxide desulfurizers. For example, the active components ZnO, MnO or Fe2O3 in conventional zinc oxide desulfurizers adsorb hydrogen sulfide to form substances such as ZnS, MnS or Fe2OS, and the alkalinity of the desulfurizer decreases. The active components such as ZnO, MnO or Fe2O3 are covered on the surface of the desulfurizer, blocking the contact between the active components and the hydrogen sulfide in the coal gas, thereby reducing the adsorption strength of hydrogen sulfide and the adsorption capacity. Among them, PKa is the acid dissociation constant of the substance. The larger the PKa, the weaker the acidity and the stronger the alkalinity of the substance.

[0024] Preferably, in the first stage of the present invention, the atmosphere of nitrogen and carbon dioxide is used. Within the preferred carbon dioxide concentration range of the present invention, as the carbon dioxide concentration increases, the concentration of carbon dioxide adsorbed by the desulfurizer increases, the alkalinity strength of the formed three-effect composite ZnO-NH3-CO2 increases, and the adsorption rate of hydrogen sulfide increases. However, when the carbon dioxide concentration is higher than 90%, the alkalinity of the three-effect composite tends to be flat or even slightly decreased.

[0025] In the second stage of roasting, the mixed gas atmosphere of the first stage is replaced with an air atmosphere. The temperature of the air atmosphere entering the roasting system is maintained at 200℃~205℃ to prevent a drastic temperature change that causes the desulfurizer to pulverize. The purpose of replacing with an air atmosphere is to perform high-temperature aerobic oxidation on the cellulose forming agent used in the desulfurizer production process to volatilize the cellulose, which not only eliminates the negative impact of cellulose on the zinc oxide desulfurizer's adsorption of hydrogen sulfide, but also the volatilization of cellulose can increase the volume pore volume of the zinc oxide desulfurizer, increase the contact area between hydrogen sulfide and the active components of the desulfurizer, and enhance the desulfurizer's ability to adsorb hydrogen sulfide.

[0026] The invention also provides a zinc oxide desulfurizer for high-precision desulfurization of coal gas, which is prepared by the preparation method.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] The present invention scientifically adjusts the formula, the preparation process, especially the roasting process, and obtains a desulfurizer precursor with excellent components. A solid superbase intermediate that is completely different from the conventional technology is prepared through a unique first-stage roasting process, thereby avoiding various adverse effects of the conventional technology. Combined with the subsequent second-stage roasting, a desulfurizer with more superior pore size conditions and stronger hydrogen sulfide adsorption performance is finally formed. The raw materials are cheap and easy to obtain, the operation steps are simple, the repeatability is strong, the method is suitable for batch production, and is conducive to industrial promotion.

[0029] The zinc oxide desulfurizer provided by the present invention for high-precision desulfurization of coal gas has an adsorption capacity of up to 40% for hydrogen sulfide at 300°C, which is significantly higher than 29% to 31% of conventional zinc oxide desulfurizers; and the zinc oxide desulfurizer provided by the present invention has no desulfurization phenomenon during the entire life cycle operation process, and the hydrogen sulfide concentration at the outlet of the zinc oxide desulfurization tower can be stably maintained at 0.1ppm for a long time, while the conventional zinc oxide desulfurizer has obvious desulfurization phenomenon during the desulfurization process, and the hydrogen sulfide concentration at the outlet of the desulfurization tower is as high as 0.6 to 2.5ppm. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] It should be noted that the purity of the zinc oxide powder used in the present invention is ≥95%, and the specific surface area is ≥40m 2 / g, pore volume ≥0.3cc / g, sulfate impurity content ≤0.5%. The extrusion equipment used is a hydraulic extruder, the pressure of the hydraulic extruder is 200-300t, the extrusion shape is columnar, and the diameter size is The length of the extruded strip is 10 to 15 mm.

[0032] Example 1

[0033] This embodiment provides a method for preparing a zinc oxide desulfurizer, and the specific steps are as follows:

[0034] 1. Prepare the mud: mix 100 kg zinc oxide powder, 1 kg hydroxypropyl methylcellulose, 10 kg basic zinc carbonate, 15 kg ammonium chloride and 25 kg deionized water for 2 hours;

[0035] 2. Clay curing: Curing the clay produced by mixing in step 1, the curing conditions are: ambient temperature 60°C, ambient humidity 90%, and curing time 10h;

[0036] 3. Extrusion molding: The clay cured in step 2 is extruded to obtain a diameter of The columnar extruded strips with a length of 10 to 15 mm are the desulfurization agent precursor;

[0037] 4. Drying: Dry the desulfurizer precursor obtained in step 3 at 120°C for 3 hours;

[0038] 5. Calcination: Strengthen calcination under special working conditions. Strengthen calcination is divided into the following two stages:

[0039] The first stage of calcination: the desulfurization agent precursor dried in step 4 is placed in a mixed atmosphere of nitrogen and carbon dioxide, the temperature is increased from 120°C to 200°C, the heating rate is 2°C / min, and it stays at 200°C for 7 hours. The gas of the mixed atmosphere only circulates inside the calcination system and does not exchange heat or components with the outside. The concentration of carbon dioxide in the mixed atmosphere is 60%, and the concentration of nitrogen is 40%, wherein the oxygen content in the mixed gas needs to be ≤0.1%;

[0040] The second stage of roasting: the mixed atmosphere of the first stage of roasting is gradually replaced by hot air. The air needs to be heated to 200°C before entering the roasting system. When the oxygen content in the atmosphere gas in the roasting system reaches 20% and the carbon dioxide concentration is lower than 0.1%, the temperature is raised to 330°C to start roasting. The heating rate is 5°C / min. After roasting at the highest temperature of 330°C for 5 hours, the intensive roasting stage is ended. When the temperature drops to room temperature, the zinc oxide desulfurizer for high-precision desulfurization of coal gas is obtained.

[0041] Example 2

[0042] This embodiment provides a method for preparing a zinc oxide desulfurizer, and the specific steps are as follows:

[0043] 1. Prepare the clay material: same as in Example 1;

[0044] 2. Clay material maintenance: same as in Example 1;

[0045] 3. Extrusion molding: same as in Example 1;

[0046] 4. Drying: same as in Example 1;

[0047] 5. Calcination: Strengthen calcination under special working conditions. Strengthen calcination is divided into the following two stages:

[0048] The first stage of calcination: the desulfurization agent precursor dried in step 4 is placed in a mixed atmosphere of nitrogen and carbon dioxide, the temperature is increased from 120°C to 200°C, the heating rate is 2°C / min, and it stays at 200°C for 7 hours. The gas of the mixed atmosphere only circulates inside the calcination system and does not exchange heat or components with the outside. The concentration of carbon dioxide in the mixed atmosphere is 80%, and the concentration of nitrogen is 20%, wherein the oxygen content in the mixed gas needs to be ≤0.1%;

[0049] The second stage of roasting: the mixed atmosphere of the first stage of roasting is gradually replaced by hot air. The air needs to be heated to 200°C before entering the roasting system. When the oxygen content in the atmosphere gas in the roasting system reaches 20% and the carbon dioxide concentration is lower than 0.1%, the temperature is raised to 330°C to start roasting. The heating rate is 5°C / min. After roasting at the highest temperature of 330°C for 5 hours, the intensive roasting stage is ended. When the temperature drops to room temperature, the zinc oxide desulfurizer for high-precision desulfurization of coal gas is obtained.

[0050] Example 3

[0051] This embodiment provides a method for preparing a zinc oxide desulfurizer, and the specific steps are as follows:

[0052] 1. Prepare the mud: mix 100 kg zinc oxide powder, 1 kg hydroxypropyl methylcellulose, 10 kg basic zinc carbonate, 20 kg ammonium chloride and 25 kg deionized water for 2 hours;

[0053] 2. Clay material maintenance: same as in Example 1;

[0054] 3. Extrusion molding: same as in Example 1;

[0055] 4. Drying: same as in Example 1;

[0056] 5. Calcination: Strengthen calcination under special working conditions. Strengthen calcination is divided into the following two stages:

[0057] The first stage of calcination: the desulfurization agent precursor dried in step 4 is placed in a mixed atmosphere of nitrogen and carbon dioxide, the temperature is increased from 120°C to 200°C, the heating rate is 2°C / min, and it stays at 200°C for 7 hours. The gas of the mixed atmosphere only circulates inside the calcination system and does not exchange heat or components with the outside. The concentration of carbon dioxide in the mixed atmosphere is 80%, and the concentration of nitrogen is 20%, wherein the oxygen content in the mixed gas needs to be ≤0.1%;

[0058] The second stage of roasting: the mixed atmosphere of the first stage of roasting is gradually replaced by hot air. The air needs to be heated to 200°C before entering the roasting system. When the oxygen content in the atmosphere gas in the roasting system reaches 20% and the carbon dioxide concentration is lower than 0.1%, the temperature is raised to 330°C to start roasting. The heating rate is 5°C / min. After roasting at the highest temperature of 330°C for 5 hours, the intensive roasting stage is ended. When the temperature drops to room temperature, the zinc oxide desulfurizer for high-precision desulfurization of coal gas is obtained.

[0059] Comparative Example 1

[0060] The difference from Example 3 is that: Step 5, calcination, the desulfurizer precursor dried in Step 4 is first calcined at 200°C at 2°C / min for 7h in a mixed atmosphere of nitrogen and carbon dioxide, and then calcined at 330°C at 5°C / min for 5h.

[0061] Comparative Example 2

[0062] The difference from Example 3 is that in step 5, calcination, the desulfurizer precursor dried in step 4 is firstly heated to 200°C at 2°C / min in air atmosphere for 7h, and then heated to 330°C at 5°C / min for 5h.

[0063] Comparative Example 3

[0064] The difference from Example 3 is that: Step 5, calcination, the desulfurizer precursor dried in Step 4 is first calcined at 200°C at 2°C / min under air atmosphere for 7 hours, and then the air atmosphere is replaced with a mixed atmosphere of nitrogen (20%) and carbon dioxide (80%) and the temperature is increased to 330°C at 5°C / min and calcined for 5 hours.

[0065] Comparative Example 4

[0066] The difference from Example 3 is that when preparing the mud in step 1, the amount of the synergist ammonium chloride is 0, and the other steps are the same.

[0067] Comparative Example 1

[0068] Comparative Example 1 is an existing conventional zinc oxide desulfurizer, and its preparation method is as follows:

[0069] 1. Prepare the mud: mix 100 kg zinc oxide powder, 1 kg hydroxypropyl methylcellulose, 10 kg basic zinc carbonate and 25 kg deionized water for 2 hours;

[0070] 2. Clay material maintenance: same as in Example 1;

[0071] 3. Extrusion molding: same as in Example 1;

[0072] 4. Drying: same as in Example 1;

[0073] 5. Calcination: The desulfurizer dried in step 4 is heated from 120°C to 200°C in an air atmosphere at a heating rate of 2°C / min, and stays at 200°C for 7 hours, then heated to 330°C at a rate of 5°C / min, and calcined at a maximum temperature of 330°C for 5 hours. The calcination is terminated and the temperature is reduced to room temperature to obtain a conventional zinc oxide desulfurizer.

[0074] The zinc oxide desulfurizer provided in the embodiment, control example and comparative example was used for gas desulfurization to carry out performance testing, and the implementation standards were as follows:

[0075] 1. Hydrogen sulfide adsorption capacity / %, the test is carried out in accordance with HG / T2513-2014;

[0076] 2. Radial crushing strength / N·cm-, tested in accordance with HG / T2782-2011;

[0077] 3. Use the average sulfur release over 168 hours / ppm, and the detection shall comply with Appendix E of HG / T2513-2014.

[0078] The test results are shown in Table 1 below:

[0079] Table 1 Test results of coal gas desulfurization performance of zinc oxide desulfurizer provided in the embodiment and the comparative example

[0080]

[0081] It can be seen from Table 1 that, compared with the conventional zinc oxide desulfurizer provided in Comparative Example 1, the zinc oxide desulfurizer prepared in Examples 1 to 3 not only greatly improves the hydrogen sulfide adsorption capacity when desulfurizing coal gas, but also successfully avoids the occurrence of sulfur release; the present application first adds the desulfurization synergist component ammonium chloride, and optimizes the roasting process. By setting the roasting atmosphere to nitrogen and carbon dioxide in the first stage, the carbon dioxide in the roasting process forms a triple-effect solid superbase with the zinc oxide component and the ammonium chloride component in the zinc oxide desulfurizer, thereby improving the performance of the desulfurizer;

[0082] Example 2 Based on Example 1, the concentration of carbon dioxide during the roasting process is increased to 80%, thereby enhancing the super alkalinity of Zn-NH3-CO2 and improving the hydrogen sulfide adsorption capacity of the zinc oxide desulfurizer. The average sulfur release of the desulfurizer in 168h is 0ppm;

[0083] Example 3, based on Example 2, increases the concentration of the synergist ammonium chloride component, enhances the super-alkalinity of Zn-NH3-CO2, maintains the average sulfur release of the desulfurizer at 0 ppm in 168 hours, and further improves the hydrogen sulfide adsorption capacity of the zinc oxide desulfurizer;

[0084] The formula of Control Example 1 is basically the same as that of Example 3, but the roasting operation is different. The roasting atmosphere of Control Example 1 is all nitrogen and carbon dioxide. Since the roasting atmosphere in the second stage is not replaced and is still nitrogen and carbon dioxide, the organic component cellulose in the desulfurizer does not volatilize, and the cellulose covers the surface of zinc oxide to form an organic film, which isolates the contact with hydrogen sulfide, so the adsorption capacity of hydrogen sulfide is greatly reduced. However, because of the presence of ammonium chloride synergistic component and the adsorption of carbon dioxide in the first stage of roasting, the desulfurizer prepared by this method is still higher than that of Control Example 1, but sulfur release occurs, and the average sulfur release in 168h is 0.05ppm;

[0085] Compared with Example 3, the atmosphere of the roasting components in Comparative Example 2 is all air atmosphere, and since no carbon dioxide is adsorbed to form a triple-effect super base, the adsorption capacity of the prepared desulfurizer for hydrogen sulfide is low, but there is an ammonium chloride synergistic component, so the desulfurizer prepared by this method is still higher than that of Comparative Example 1;

[0086] Compared with Example 3, Control Example 3 changes the order of the roasting atmosphere. The first roasting stage uses an air atmosphere, and the second roasting stage uses a mixed gas atmosphere (nitrogen concentration 20%, carbon dioxide concentration 80%). Because the air roasting atmosphere temperature in the first stage is relatively low, the organic components such as cellulose are not burned. In the second stage, there is no oxygen at high temperature, and the organic components cannot burn and volatilize. The organic component cellulose in the desulfurizer does not volatilize, and the cellulose covers the surface of zinc oxide to form an organic film, isolating it from contact with hydrogen sulfide. In addition, the roasting temperature in the second stage is relatively high, and the adsorption strength of the desulfurizer on carbon dioxide is very poor, and it is impossible to form a high-quality Zn-NH3-CO2 superbase. Therefore, the prepared desulfurizer has a poor adsorption capacity for hydrogen sulfide, and the average sulfur release in 168 hours is 0.01ppm;

[0087] Compared with Example 3, the preparation formula of Control Example 4 removes the synergist ammonium chloride, and the other processes remain unchanged. Because no Zn-NH3-CO2 superbase is formed, the desulfurizer performance is poor, and the average sulfur release in 168 hours is 0.08ppm;

[0088] It can be seen from Table 1 that the zinc oxide desulfurizer provided by the embodiment of the present invention has a high adsorption strength for hydrogen sulfide in coal gas. The conventional zinc oxide desulfurizer releases 0.5ppm~2.0ppm of hydrogen sulfide during the desulfurization process, that is, the concentration of hydrogen sulfide at the outlet of the zinc oxide desulfurization tower increases from a stable 0.1ppm to 0.6~2.5ppm. The zinc oxide desulfurizer provided by the present invention does not release sulfur during the entire life cycle operation process, and the concentration of hydrogen sulfide at the outlet of the zinc oxide desulfurization tower can be stably maintained at 0.1ppm for a long time, which completely solves the problem of sulfur release caused by the poor adsorption strength of hydrogen sulfide in the desulfurization process of conventional products.

[0089] Please note that the technical features of the above embodiments can be combined arbitrarily. In order to make the description concise, all possible combinations of the technical features in the above embodiments are not described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification. The above embodiments only express several implementation methods of the present application, and their descriptions are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that for ordinary technicians in this field, without departing from the concept of the present application, several variations and improvements can be made, which all belong to the scope of protection of the present application. Therefore, the scope of protection of the patent in this application shall be based on the attached claims.

Claims

1. A method for preparing a zinc oxide desulfurizer for high-precision desulfurization of coal gas, characterized in that: The preparation method comprises the following steps: S1: Mix zinc oxide powder, additives and water in a certain proportion to prepare a slurry; S2: Extruding the mud obtained in S1 to obtain a desulfurizer precursor; S3: drying and calcining the desulfurizing agent precursor obtained in S2 to obtain the zinc oxide desulfurizing agent; The auxiliary agent includes: any one or more of a molding agent, a pore-forming agent, and a synergist.

2. The preparation method according to claim 1, characterized in that: The purity of the zinc oxide powder is ≥95%; Preferably, the specific surface area of ​​the zinc oxide powder is ≥40m 2 / g; Preferably, the pore volume of the zinc oxide powder is ≥0.3cc / g; Preferably, the sulfate impurity content in the zinc oxide powder is ≤0.5%.

3. The preparation method according to claim 1, characterized in that: The molding agent is selected from any one or more of hydroxypropyl methylcellulose, carboxymethyl cellulose, and hydroxyethyl cellulose; The pore former includes basic zinc carbonate; The synergist includes ammonium chloride; The water is demineralized water.

4. The preparation method according to claim 1 or 3, characterized in that: The certain proportion includes: in terms of mass fraction, the molding agent accounts for 1% to 3% of the mass of the zinc oxide powder; the pore-forming agent accounts for 10% to 15% of the mass of the zinc oxide powder; the synergist accounts for 15% to 20% of the mass of the zinc oxide powder; and the water accounts for 25% to 33% of the mass of the zinc oxide powder.

5. The preparation method according to claim 1, characterized in that: The mixing time is 2 to 2.5 hours.

6. The preparation method according to claim 1, characterized in that: After step S1 and before step S2, the method further includes: curing the mud obtained in step S1; The curing treatment conditions are: maintaining the ambient temperature at 50-80° C. and the ambient humidity at 60%-90% for 10-12 hours.

7. The preparation method according to claim 1, characterized in that: The drying temperature is 120°C and the drying time is 3-4h; The calcination temperature is 120-330°C.

8. The preparation method according to claim 1, characterized in that: The roasting is enhanced roasting; the enhanced roasting includes a first stage roasting and a second stage roasting performed sequentially: The first stage calcination comprises: heating the dried desulfurization agent precursor from 120° C. to 200° C. at a heating rate of 2° C. / min in a mixed atmosphere of nitrogen and carbon dioxide, and staying at 200° C. for 7 hours; The second stage roasting includes: first, gradually replacing the mixed atmosphere of the first stage roasting with hot air at 200-205°C; when the oxygen content of the atmosphere in the roasting system reaches 20% and the carbon dioxide concentration is lower than 0.1%, starting to heat up at 5°C / min, roasting for 5 hours after reaching the target temperature of 330°C, and waiting to cool to room temperature to obtain the zinc oxide desulfurizer for high-precision desulfurization of coal gas.

9. The preparation method according to claim 8, characterized in that: During the first stage of roasting, the mixed atmosphere circulates only inside the roasting system and does not exchange heat or components with the outside world; The concentration of carbon dioxide in the mixed atmosphere is 60% to 85%, the concentration of nitrogen is 15% to 40%, and the oxygen content is required to be ≤0.1%.

10. A zinc oxide desulfurizer for high-precision desulfurization of coal gas, characterized in that: The zinc oxide desulfurizer is prepared by the preparation method according to any one of claims 1 to 9.

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