Desulfurizing agent for large SNG fine desulfurization device and preparation method thereof

Abstract

The invention provides a desulfurizing agent for a large SNG fine desulfurization device and a preparation method thereof, the desulfurizing agent comprises a carrier, active components, a first auxiliary agent and a second auxiliary agent, the carrier is Al2O3, the active components are ZnO and CuO, the first auxiliary agent is La2O3 or CeO2, and the second auxiliary agent is selected from one or more of TiO2, MgO and CaO; the desulfurizing agent is prepared from the following components in percentage by mass: 25 to 50 percent of ZnO, 25 to 45 percent of CuO, 1 to 5 percent of first aid, 0.5 to 10 percent of second aid and the balance of carrier Al2O3. Compared with the prior art, the desulfurizer disclosed by the invention can be used in a wide-temperature environment (170-230 DEG C), the desulfurization effect is good, and the sulfur content after desulfurization is lower than 4ppb; by adding the first aid La2O3 and the second aid, the slight methanol synthesis reaction of Cu in the desulfurizing agent can be inhibited, the content of byproduct methanol in the tail gas is reduced, and the desulfurizing effect is ensured; the carrier Al2O3 is high in strength and good in stability, and the desulfurizer is suitable for industrial application.

Description

Technical Field

[0001] The invention relates to the technical field of desulfurizing agents, and in particular to a desulfurizing agent used in a large-scale SNG fine desulfurization device and a preparation method thereof. Background Art

[0002] my country has a long history of research on fine desulfurization processes and desulfurizers for chemical manufacturing. Among them, Huashuo Technology Co., Ltd. (formerly Hubei Institute of Chemistry), Northwest Institute of Chemical Industry, Beijing Sanju Company and other companies have done a lot of research work and developed their own desulfurizers and supporting desulfurization processes.

[0003] More than a decade ago, the desulfurization capacity index of large-scale domestic chemical production facilities was 10ppm, resulting in a service life of desulfurization agents related to downstream synthesis of about 2 years. As the desulfurization index of large-scale domestic natural gas production facilities has been changed to below 4ppb, domestic desulfurization agents have not been completely replaced.

[0004] Since the operating temperature of the desulfurization tank of the methanation unit of a large-scale coal-to-natural gas project is between 170-230°C, this temperature range is already at the lower limit of the desulfurizer for the methanol synthesis reaction. The synthesis gas may undergo a slight methanol synthesis reaction with the Cu in the desulfurizer. Inhibiting this side reaction is the key to whether the fine desulfurizer can be used in the methanation process.

[0005] Therefore, there is a need for a desulfurizing agent that can be suitable for use in a large-scale SNG production fine desulfurization device. Summary of the invention

[0006] In order to solve the above technical problems, the present invention provides a desulfurizer for a large-scale SNG fine desulfurization device and a preparation method thereof. The desulfurizer has excellent performance, high wear resistance, and good removal effect on organic sulfur.

[0007] To achieve this technical purpose, the present invention adopts the following scheme: In the first aspect, the present invention provides a desulfurizer for a large-scale SNG fine desulfurization device, including a carrier, an active component, a first auxiliary agent and a second auxiliary agent, the carrier is Al2O3, the active components are ZnO and CuO, the first auxiliary agent is La2O3 or CeO2, and the second auxiliary agent is one or more of TiO2, MgO, and CaO; in terms of mass percentage, the desulfurizer includes ZnO: 25-50%, CuO: 25-45%, the first auxiliary agent: 1-5%, the second auxiliary agent: 0.5-10%, and the balance is the carrier Al2O3.

[0008] On the other hand, the present invention also provides a method for preparing a desulfurizer for a large-scale SNG fine desulfurization device, comprising the following steps: S1, mixing the active component, the precursor of the first auxiliary agent and the precursor of the second auxiliary agent and dissolving them in deionized water to obtain solution I; S2, adding the precipitant into deionized water to dissolve, and preparing solution II and solution II' of different concentrations respectively; S3, adding the precursor of the carrier into deionized water to prepare solution III; S4, adding solution I to solution II for precipitation to obtain precipitation system I; adding solution II' to solution III for precipitation to obtain precipitation system II; S5, mixing precipitation system I with precipitation system II, stirring for 0.5 to 10 hours and then standing for 0.5 to 10 hours; S6. The mixture is precipitated, filtered, dried, roasted and molded to form a desulfurizer.

[0009] Furthermore, the temperature of the deionized water used to prepare the solution in steps S1-S3 is 40-90° C. The molar concentration of solution I to solution II is 1:1.0-5.0, and the molar concentration ratio of solution II' to solution III is 1:1.0-5.0.

[0010] Furthermore, in the process of preparing precipitation system I in step S4, the volume ratio of solution I to solution II is 1:1.5-4.5, preferably 1:3-4.

[0011] Furthermore, in the process of preparing precipitation system II in step S4, the volume ratio of solution III to solution II' is 1:3-9, preferably 1:4.5-6.

[0012] Furthermore, in step S5, the volume ratio of precipitation system I to precipitation system II is 1:0.1-14.8, preferably 1:0.4-6.

[0013] Furthermore, step S6 specifically includes: washing, filtering, drying and calcining the mixed precipitation system, adding graphite and cellulose to the filter residue after calcination, mixing evenly and pressing into tablets to obtain a desulfurizer; wherein the drying temperature is 70-110°C, the calcination temperature is 400-500°C, and the masses of graphite and cellulose are 1-5% and 0.5-5% of the mass of the filter residue after calcination, respectively.

[0014] Furthermore, the precursors of the active component, the first auxiliary agent and the second auxiliary agent are soluble salts containing corresponding metal ions, for example, the precursors are selected from one or more of nitrates, chlorides and carbonates containing corresponding metal cations.

[0015] Furthermore, the precursor of the carrier is one or more of aluminum nitrate, aluminum chloride, and pseudo-boehmite.

[0016] Furthermore, the precipitant is Na2CO3 or NaHCO3 or a mixture of the two.

[0017] Compared with the prior art, the present invention has the following beneficial effects: The desulfurizer of the present invention can be used in a wide temperature environment (170-230° C.), has a good desulfurization effect, and the sulfur content after desulfurization is less than 4 ppb; the addition of the first auxiliary agent La2O3 and the second auxiliary agent can inhibit the slight methanol synthesis reaction of Cu in the desulfurizer, reduce the content of byproduct methanol in the tail gas, and ensure the desulfurization effect; the carrier A12O3 has high strength and good stability, and the desulfurizer is suitable for industrial application. DETAILED DESCRIPTION

[0018] In order to fully understand the purpose, features and effects of the present invention, the present invention is described in detail through the following specific implementation methods, but the present invention is not limited thereto. Example 1

[0019] S1. Weigh 33.41 g Zn(NO3)2·6H2O, 25.10 g Cu(NO3)2·2.5H2O, 5.74 g La(NO3)3·6H2O, 4.36 g Ti(NO3)4·5H2O, and 9.55 g Ca(NO3)2·4H2O and dissolve them in 300 ml deionized water at 60°C to obtain solution I.

[0020] S2. Weigh 41.59 g Na2CO3 and dissolve it in 300 ml deionized water at 60°C to obtain solution II; weigh 35.68 g NaHCO3 and dissolve it in 300 ml deionized water at 60°C to obtain solution II'.

[0021] S3. Weigh 71.27 g of Al(NO3)3·9H2O and dissolve it in 300 ml of deionized water at 60°C to obtain solution III.

[0022] S4. Slowly add solution Ⅰ into solution Ⅱ and stir for 2 hours to obtain precipitation system Ⅰ; slowly add solution Ⅱ' into solution Ⅲ and stir for 2 hours to obtain precipitation system Ⅱ.

[0023] S5. Add precipitation system II into precipitation system I, stir for 2 hours and then let stand for 2 hours.

[0024] S6. Wash the precipitate system obtained in step S5 with deionized water at 60°C for 6 times and filter; dry the filter residue in a 110°C blast oven for 12 hours, and then heat to 450°C at a rate of 1°C / min and calcine for 6 hours to obtain 31.2 g of the product, add 1% of graphite and 0.5% of cellulose to the filter residue, mix well, and press into a Φ3*3mm cylindrical commercial product to obtain a desulfurizer.

[0025] The desulfurizer composition is: 40% ZnO, 40% CuO, 3% La2O3, 1% TiO2, 3% CaO, 13% Al2O3. Example 2

[0026] The preparation method and steps of the desulfurizer are basically the same as those in Example 1, wherein the precursors and contents of the active components, auxiliary agents, carriers, and precipitants are shown in Table 1 (unit in the table: g).

[0027] Table 1

[0028] The desulfurizer composition is: 30% ZnO, 30% CuO, 3% La2O3, 4% TiO2, 6% CaO, 27% Al2O3. Example 3

[0029] The preparation method and steps of the desulfurizer are basically the same as those in Example 1, wherein the precursors and contents of the active components, auxiliary agents, carriers, and precipitants are shown in Table 2 (unit in the table: g).

[0030] Table 2

[0031] The desulfurizer composition is: 45% ZnO, 45% CuO, 1% La2O3, 2% TiO2, 3% CaO, 4% Al2O3. Example 4

[0032] The preparation method and steps of the desulfurizer are basically the same as those in Example 1, wherein the precursors and contents of the active components, auxiliary agents, carriers, and precipitants are shown in Table 3 (unit in the table: g).

[0033] Table 3

[0034] The desulfurizer composition is: 40% ZnO, 40% CuO, 3% La2O3, 1% TiO2, 3% MgO, 13% Al2O3. Example 5

[0035] The preparation method and steps of the desulfurizer are basically the same as those in Example 1, wherein the precursors and contents of the active components, auxiliary agents, carriers, and precipitants are shown in Table 4 (unit in the table: g).

[0036] Table 4

[0037] The desulfurizer composition is: 40% ZnO, 40% CuO, 3% La2O3, 2% MgO, 2% CaO, 13% Al2O3. Example 6

[0038] The preparation method and steps of the desulfurizer are basically the same as those in Example 1, wherein the precursors and contents of the active components, auxiliary agents, carriers, and precipitants are shown in Table 5 (unit: g).

[0039] Table 5

[0040] The desulfurizer composition is: 40% ZnO, 40% CuO, 3% La2O3, 2% MgO, 2% CaO, 13% Al2O3. Example 7

[0041] The preparation method and steps of the desulfurizer are basically the same as those in Example 1, and the precipitant is a mixture of Na2CO3 and NaHCO3. The active components, auxiliary agents, carriers, precursors of the precipitant and their contents are shown in Table 6 (unit: g).

[0042] Table 6

[0043] The desulfurizer composition is: 40% ZnO, 40% CuO, 3% La2O3, 1% TiO2, 3% CaO, 13% Al2O3. Example 8

[0044] The preparation method and steps of the desulfurizer are basically the same as those in Example 1, and the first auxiliary agent is CeO2. The precursors and contents of the active components, auxiliary agents, carriers, and precipitants are shown in Table 7 (unit: g).

[0045] Table 7

[0046] The desulfurizer composition is: 40% ZnO, 40% CuO, 3% CeO2, 1% TiO2, 3% CaO, 13% Al2O3. Comparative Example 1

[0047] The preparation method and steps of the desulfurizer are basically the same as those in Example 1, wherein the first auxiliary agent is not included. The precursors and contents of other active components, auxiliary agents, and carriers are shown in Table 8 (unit in the table: g).

[0048] Table 8

[0049] The desulfurizer composition is: 40% ZnO, 40% CuO, 4% TiO2, 3% MgO, 13% Al2O3. Comparative Example 2

[0050] Purchased a sample of refined desulfurizer from an imported company.

[0051] The desulfurizers in the above examples and comparative examples were tested for performance, and the testing method was as follows: The raw gas contains 1% H2S and 100ppm thiophene by volume, and the rest is high-purity N2. The air velocity is set to 1500h-1 The reaction temperature was raised to 170°C at a rate of 1°C / min and operated in the range of 170-230°C. The test pressure was 0.2MPa. The desulfurizer loading was 0.5ml. The total sulfur content in the tail gas was determined using a Canadian Galvanic 9600L micro-sulfur analyzer.

[0052] The radial crushing strength test of the desulfurizer is carried out according to the test method of HG / T 2782 "Determination of the crushing strength of fertilizer catalyst particles".

[0053] The desulfurization agent performance evaluation results of each embodiment and comparative example are shown in Table 9.

[0054] Table 9

[0055] Through the above embodiments, the desulfurizer of the present invention has good desulfurization performance, high strength, can effectively inhibit the occurrence of side reactions, and has suitable process conditions and good application prospects.

[0056] Finally, it should be noted that the above examples are only preferred embodiments of the present invention. Of course, those skilled in the art can make changes and modifications to the present invention. If these modifications and variations fall within the scope of the claims of the present invention and their equivalent technologies, they should be considered to be within the scope of protection of the present invention.

Claims

1. A desulfurizer for a large-scale SNG fine desulfurization device, comprising a carrier, an active component, a first auxiliary agent and a second auxiliary agent, characterized in that: The carrier is Al2O3, the active components are ZnO and CuO, the first auxiliary agent is La2O3 or CeO2, and the second auxiliary agent is selected from one or more of TiO2, MgO, and CaO; in terms of mass percentage, the desulfurizer includes ZnO: 25-50%, CuO: 25-45%, the first auxiliary agent: 1-5%, the second auxiliary agent: 0.5-10%, and the balance is the carrier Al2O3.

2. A method for preparing a desulfurizer for a large-scale SNG fine desulfurization device according to claim 1, characterized in that: The following steps are involved: S1, mixing the active component, the precursor of the first auxiliary agent and the precursor of the second auxiliary agent and dissolving them in deionized water to obtain solution I; S2, adding the precipitant into deionized water to dissolve, and preparing solution II and solution II' of different concentrations respectively; S3, adding the precursor of the carrier into deionized water to prepare solution III; S4, adding solution I to solution II for precipitation to obtain precipitation system I; Adding solution II' to solution III for precipitation to obtain precipitation system II; S5, mixing precipitation system I with precipitation system II, stirring for 0.5 to 10 hours and then standing for 0.5 to 10 hours; S6. The mixture is precipitated, filtered, dried, roasted and molded to form a desulfurizer.

3. The method for preparing a desulfurizing agent for a large-scale SNG fine desulfurization device according to claim 2, characterized in that: The temperature of the deionized water used to prepare the solutions in steps S1-S3 is 40-90°C, the molar concentration ratio of solution I to solution II is 1:1.0-5.0, and the molar concentration ratio of solution II' to solution III is 1:1.0-5.

0.

4. The method for preparing a desulfurizing agent for a large-scale SNG fine desulfurization device according to claim 2, characterized in that: In the process of preparing precipitation system I in step S4, the volume ratio of solution I to solution II is 1:1.5-4.

5.

5. The method for preparing a desulfurizing agent for a large-scale SNG fine desulfurization device according to claim 2, characterized in that: In the process of preparing precipitation system II in step S4, the volume ratio of solution III to solution II' is 1:3-9.

6. The method for preparing a desulfurizing agent for a large-scale SNG fine desulfurization device according to claim 2, characterized in that: In step S5, the volume ratio of precipitation system I to precipitation system II is 1:0.1-14.

8.

7. The method for preparing a desulfurizing agent for a large-scale SNG fine desulfurization device according to claim 2, characterized in that: Step S6 specifically includes: washing, filtering, drying and calcining the mixed precipitation system, adding graphite and cellulose to the filter residue after calcination, mixing evenly and pressing into tablets to obtain a desulfurizer; wherein the drying temperature is 70-110°C, the calcination temperature is 400-500°C, and the mass of graphite and cellulose is 1-5% and 0.5-5% of the mass of the filter residue after calcination, respectively.

8. The method for preparing a desulfurizing agent for a large-scale SNG fine desulfurization device according to claim 2, characterized in that: The precursors of the active component, the first auxiliary agent and the second auxiliary agent are soluble salts containing corresponding metal ions.

9. The method for preparing a desulfurizing agent for a large-scale SNG fine desulfurization device according to claim 2, characterized in that: The precursor of the carrier is one or more of aluminum nitrate, aluminum chloride, and pseudo-boehmite.

10. The method for preparing a desulfurizing agent for a large-scale SNG fine desulfurization device according to claim 2, characterized in that: The precipitant is Na2CO3, NaHCO3 or a mixture of the two.

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