Zinc oxide desulfurizer as well as preparation method and application thereof

Abstract

The invention provides a zinc oxide desulfurizer as well as a preparation method and application thereof. The zinc oxide desulfurizer disclosed by the invention is prepared by adopting an impregnation method, C12A7 with a cage cavity structure is taken as a raw material, and the C12A7 with the cage cavity structure has abundant micro channels, so that H2S can enter the C12A7 conveniently, and meanwhile, a larger reactive surface is provided; zinc oxide is loaded by an impregnation method and has a synergistic effect with C12A7, so that the utilization efficiency of zinc oxide can be greatly improved; the zinc oxide desulfurizer is high in activity: due to a unique cage cavity structure, O2 <-> in a cage cavity and S2 <-> in raw material gas can be quickly exchanged, so that the high-activity desulfurizer with extremely high sulfide purification degree is prepared; at normal temperature, the sulfur capacity is greater than 12%; the zinc oxide desulfurizer disclosed by the invention is high in strength: the crushing strength of particles is greater than or equal to 80N / cm; the zinc oxide desulfurizer has the advantages of low zinc oxide content (less than or equal to 40%), cheap and easily available raw materials and low cost.

Description

Technical Field

[0001] The invention relates to the technical field of desulfurization, and in particular to a zinc oxide desulfurizer and a preparation method and application thereof. Background Art

[0002] With the continuous development of petrochemical and fine chemical industries in my country, various new high-efficiency catalysts are being used more and more. These high-efficiency catalysts are more sensitive to sulfides in chemical raw gas. Trace amounts of sulfides will cause poisoning and failure of high-efficiency catalysts. Therefore, it is necessary to remove organic sulfur and inorganic sulfur from chemical raw gas. It is difficult to remove organic sulfur from chemical raw gas. Although the method of high-temperature cobalt-molybdenum hydrogenation and zinc oxide can basically remove organic sulfides and inorganic sulfides, the process route is complicated, the operating conditions are harsh, the investment cost is huge, and it is difficult to achieve a high desulfurization accuracy (<0.1ppm). Therefore, this method is difficult to promote and use in my country.

[0003] Among many types of dry desulfurizers, zinc oxide occupies an important position due to its high desulfurization accuracy, stable and convenient operation, and high sulfur capacity (weight percentage). The conventional operating temperature of this type of desulfurizer is generally above 200°C. In recent years, from the perspective of rational use of thermal energy and energy saving and consumption reduction, both domestic and foreign countries have been committed to the development and research of low-temperature and normal-temperature fine desulfurizers. It is quite difficult to achieve dry fine desulfurization under normal temperature conditions. The sulfur capacity of normal-temperature zinc oxide desulfurizer is much lower than that of the commonly used high-temperature zinc oxide desulfurizer. Its formula requires the use of special zinc oxide (such as activated zinc oxide), which is more expensive.

[0004] At present, domestic zinc oxide desulfurizers contain a high content of zinc oxide and are mainly suitable for high-temperature desulfurization. The main domestic zinc oxide desulfurizer technologies listed in HG / T2508 are shown in Table 1 below:

[0005] Table 1- Technical requirements of zinc oxide desulfurizer

[0006]

[0007]

[0008] As can be seen from Table 1, the zinc oxide content of domestic zinc oxide desulfurizer is very high (≥80%), which results in high cost. Moreover, most of them are only suitable for high temperature (220°C and above), and the sulfur capacity at room temperature is low (<10%), and the purification degree is not high (≤0.1ppm). A large amount of zinc oxide in the desulfurizer is not effectively utilized, resulting in waste of resources and excessive cost.

[0009] Based on the defects of the current zinc oxide desulfurizer, it is necessary to improve it. Summary of the invention

[0010] The purpose of the present invention is to provide a zinc oxide desulfurizer with low cost, high sulfur capacity, high purification degree and suitable for room temperature and a preparation method thereof; the zinc oxide desulfurizer is a supported catalyst, with calcium heptaaluminate (12CaO·7Al2O3, referred to as C12A7) having a cage structure as a carrier, and the active component Zn is loaded by an impregnation method. It has the characteristics of low zinc oxide content (≤40%), high sulfur capacity (≥12%), high purification degree (≤0.01ppm), low cost, etc., and can simultaneously meet the requirements of room temperature removal of various raw gas sulfides.

[0011] To achieve the above object, the present invention adopts the following technical solutions:

[0012] In a first aspect, the present invention provides a method for preparing a zinc oxide desulfurizer, comprising the following steps:

[0013] mixing dodecaluminate heptaaluminate and zinc oxide to obtain a mixture;

[0014] adding an alkaline solution to the mixture and kneading to obtain a plastic dough;

[0015] The plastic dough is dried and then calcined to obtain a catalyst carrier;

[0016] After mixing ZnO and ammonium carbonate, adding ammonia water and stirring to obtain an impregnation solution;

[0017] The catalyst carrier is added into the impregnation solution, stirred and then dried to obtain a zinc oxide desulfurizer.

[0018] Preferably, the plastic dough is dried at 100-150° C. for 2-12 hours, and then calcined at 400-500° C. for 2-4 hours to obtain the catalyst carrier.

[0019] Preferably, the catalyst carrier is added to the impregnation solution, stirred, and then dried at 180 to 250° C. for 2 to 12 hours to obtain a zinc oxide desulfurizer.

[0020] Preferably, the alkaline solution comprises an aqueous NaOH solution and / or an aqueous KOH solution;

[0021] The mass concentration of the alkaline solution is 10-20%.

[0022] Preferably, dodecalcium heptaaluminate and zinc oxide are mixed to obtain a mixture, and in the step of adding an alkaline solution to the mixture, the mass ratio of dodecalcium heptaaluminate, zinc oxide, and alkaline solution is (70-90):(10-30):(25-50).

[0023] Preferably, after mixing ZnO and ammonium carbonate, adding ammonia water, stirring to obtain an impregnation solution, and in the step of adding the catalyst support to the impregnation solution, the mass volume ratio of ZnO, ammonium carbonate, catalyst support, and ammonia water is (1-5) g: (2-6) g: (45-49) g: (15-16) mL;

[0024] The mass concentration of the ammonia water is 20-25%.

[0025] Preferably, the method for preparing dodecalcium heptaaluminate comprises the following steps:

[0026] Mixing an aluminum source and a calcium source to obtain a mixed powder;

[0027] Add nitric acid to water to obtain an acid solution;

[0028] Adding the mixed powder into the acid solution and mixing to obtain a wet powder;

[0029] The wet powder is dried at 100-150°C for 2-12 hours, and then calcined at 600-700°C for 2-4 hours to obtain dodecaluminate heptaaluminate having a cage structure;

[0030] The aluminum source is pseudo-boehmite;

[0031] The calcium source is calcium hydroxide;

[0032] The molar ratio of aluminum in the aluminum source to calcium in the calcium source is 7:6;

[0033] In the step of adding nitric acid to water, the nitric acid is a nitric acid solution with a mass fraction of 65-68%, and the mass ratio of the nitric acid solution to water is (3-5):(48-50);

[0034] In the steps of mixing an aluminum source and a calcium source to obtain a mixed powder and adding nitric acid into water, the molar ratio of aluminum in the aluminum source to water is 1:(2.67-2.78).

[0035] In a second aspect, the present invention further provides a zinc oxide desulfurizer, which is prepared by the preparation method.

[0036] In a third aspect, the present invention also provides a zinc oxide desulfurizer prepared by the preparation method or the use of the zinc oxide desulfurizer in removing sulfides from raw gas.

[0037] Preferably, the zinc oxide desulfurizer is used under the following conditions: reaction temperature is 20-30°C, space velocity is 500-2000h -1 .

[0038] The zinc oxide desulfurizer and its preparation method of the present invention have the following beneficial effects compared with the prior art:

[0039] The zinc oxide desulfurizer of the present invention is prepared by an impregnation method, using C12A7 with a cage structure as a raw material. The C12A7 with a cage structure has abundant micro-channels, which facilitates the entry of H2S and provides a larger reactive surface. The zinc oxide is loaded by the impregnation method, which has a synergistic effect with C12A7 and can greatly improve the utilization efficiency of zinc oxide. The zinc oxide desulfurizer of the present invention has high activity: due to the unique cage structure, the O in the cage cavity 2- S in the raw gas 2- Rapid exchange can be carried out, thereby obtaining a highly active desulfurizer with extremely high sulfide purification degree; under normal temperature conditions, when the H2S content in the imported raw gas is ≤1000ppm, the H2S content in the outlet purified gas is less than 0.01ppm, and the sulfur capacity is greater than 12% at this time; the zinc oxide desulfurizer of the present invention has a high purification degree: under normal temperature conditions, when the H2S content in the imported raw gas is ≤1000ppm, the H2S content in the outlet purified gas is less than 0.01ppm; the zinc oxide desulfurizer of the present invention has high strength: the particle crushing strength is ≥80N / cm; the zinc oxide desulfurizer of the present invention has a low zinc oxide content (≤40%), and the raw materials are cheap and easy to obtain, and the cost is low. DETAILED DESCRIPTION

[0040] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. 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.

[0041] It should be noted that the order of description of the following embodiments is not intended to limit the preferred order of the embodiments. In addition, in the description of the present application, the term "including" means "including but not limited to". Various embodiments of the present invention may be in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity and should not be understood as a rigid limitation on the scope of the present invention; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical values ​​within the range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as single numbers within the numbered ranges, such as 1, 2, 3, 4, 5 and 6, which apply regardless of the range. In addition, whenever a numerical range is indicated in this article, it is meant to include any cited numbers (fractions or integers) within the indicated range.

[0042] The present invention provides a method for preparing a zinc oxide desulfurizer, comprising the following steps:

[0043] S1. mixing calcium dodecaaluminate and zinc oxide to obtain a mixture;

[0044] S2, adding alkaline solution to the mixture, kneading, and obtaining a plastic dough;

[0045] S3, drying the plastic dough, and then calcining it to obtain a catalyst carrier;

[0046] S4, after mixing ZnO and ammonium carbonate, adding ammonia water, stirring, to obtain an impregnation solution;

[0047] S5. Add the catalyst carrier into the impregnation solution, stir and dry to obtain a zinc oxide desulfurizer.

[0048] The zinc oxide desulfurizer prepared by the invention comprises a catalyst carrier, wherein the catalyst carrier comprises calcium heptaaluminate (12CaO·7Al2O3, referred to as C12A7) with a cage structure, an active component ZnO is loaded by an impregnation method, and an auxiliary agent is also provided, wherein the auxiliary agent comprises Na and / or K elements. The zinc oxide desulfurizer prepared by the invention has the characteristics of low zinc oxide content (≤40%), high sulfur capacity (≥12%), high purification degree (≤0.01ppm), low cost and the like, and can simultaneously meet the requirements of room-temperature removal of sulfides in various raw gas.

[0049] In some embodiments, the plastic dough is dried at 100-150° C. for 2-12 hours, and then calcined at 400-500° C. for 2-4 hours to obtain a catalyst carrier.

[0050] In some embodiments, the catalyst carrier is added to the impregnation solution, stirred, and then dried at 180-250° C. for 2-12 hours to obtain a zinc oxide desulfurizer.

[0051] In some embodiments, the alkaline solution includes aqueous NaOH and / or aqueous KOH;

[0052] The mass concentration of the alkaline solution is 10-20%.

[0053] In some embodiments, calcium dodecanedialuminate and zinc oxide are mixed to obtain a mixture, and in the step of adding an alkaline solution to the mixture, the mass ratio of calcium dodecanedialuminate, zinc oxide, and alkaline solution is (70-90):(10-30):(25-50).

[0054] In some embodiments, after ZnO and ammonium carbonate are mixed, ammonia water is added, stirred, and an impregnation solution is obtained. In the step of adding the catalyst support to the impregnation solution, the mass volume ratio of ZnO, ammonium carbonate, catalyst support, and ammonia water is (1-5) g: (2-6) g: (45-49) g: (15-16) mL;

[0055] The mass concentration of ammonia water is 20-25%.

[0056] In some embodiments, the method for preparing dodecacalcium heptaaluminate comprises the following steps:

[0057] Mixing an aluminum source and a calcium source to obtain a mixed powder;

[0058] Add nitric acid to water to obtain an acid solution;

[0059] Adding the mixed powder into the acid solution and mixing to obtain a wet powder;

[0060] The wet powder is dried at 100-150°C for 2-12 hours, and then calcined at 600-700°C for 2-4 hours to obtain dodecacalcium heptaaluminate having a cage structure.

[0061] In some embodiments, the aluminum source is pseudo-boehmite; specifically, pseudo-boehmite is also known as monohydrated aluminum oxide, pseudo-boehmite, and its English name is Pseudo Boehmite, AlOOH·nH2O, n=0.08-0.62;

[0062] The calcium source is calcium hydroxide;

[0063] The molar ratio of aluminum in the aluminum source to calcium in the calcium source is 7:6; specifically, since the chemical formula of dodecaluminate is 12CaO·7Al2O3, in which the molar ratio of aluminum to calcium is 7:6, the molar ratio of aluminum in the aluminum source to calcium in the calcium source is 7:6;

[0064] In the step of adding nitric acid to water, the nitric acid is a nitric acid solution with a mass fraction of 65-68%, and the mass ratio of the nitric acid solution to water is (3-5):(48-50);

[0065] In the steps of mixing an aluminum source and a calcium source to obtain a mixed powder and adding nitric acid into water, the molar ratio of aluminum in the aluminum source to water is 1:(2.67-2.78).

[0066] In some embodiments, the plastic dough is placed in a mold and formed into a strip shape, and then dried at 100-150° C. for 2-12 hours, and then calcined at 400-500° C. for 2-4 hours to obtain a catalyst carrier.

[0067] Based on the same inventive concept, the present invention also provides a zinc oxide desulfurizer, which is prepared by the above-mentioned preparation method.

[0068] Based on the same inventive concept, the present invention also provides a zinc oxide desulfurizer prepared by the above preparation method or the use of the above zinc oxide desulfurizer in removing sulfides from raw gas.

[0069] In some embodiments, the conditions for using zinc oxide desulfurizer are: reaction temperature is 20-30°C, space velocity is 500-2000h-1 .

[0070] The zinc oxide desulfurizer of the present invention is prepared by an impregnation method, using C12A7 with a cage structure as a raw material. The C12A7 with a cage structure has abundant micro-channels, which facilitates the entry of H2S and provides a larger reactive surface. The zinc oxide is loaded by the impregnation method, which has a synergistic effect with C12A7 and can greatly improve the utilization efficiency of zinc oxide. The zinc oxide desulfurizer of the present invention has high activity: due to the unique cage structure, the O in the cage cavity 2- S in the raw gas 2- Rapid exchange can be carried out, thereby obtaining a highly active desulfurizer with extremely high sulfide purification degree; under normal temperature conditions, when the H2S content in the imported raw gas is ≤1000ppm, the H2S content in the outlet purified gas is less than 0.01ppm, and the sulfur capacity is greater than 12% at this time; the zinc oxide desulfurizer of the present invention has a high purification degree: under normal temperature conditions, when the H2S content in the imported raw gas is ≤1000ppm, the H2S content in the outlet purified gas is less than 0.01ppm; the zinc oxide desulfurizer of the present invention has high strength: the particle crushing strength is ≥80N / cm; the zinc oxide desulfurizer of the present invention has a low zinc oxide content (≤40%), and the raw materials are cheap and easy to obtain, and the cost is low.

[0071] The zinc oxide desulfurizer of the present application and its preparation method and application are further described below with specific examples. This section further illustrates the content of the present invention in conjunction with specific examples, but should not be construed as limiting the present invention. Unless otherwise specified, the technical means used in the examples are conventional means well known to those skilled in the art. Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the art.

[0072] Example 1

[0073] The present invention provides a method for preparing a zinc oxide desulfurizer, comprising the following steps:

[0074] S1, 0.85714 mol of calcium hydroxide powder and 1 mol of pseudo-boehmite powder are mixed to obtain a mixed powder (the molar ratio of aluminum to calcium in the mixed powder is 7:6);

[0075] S2, add 5g of nitric acid (aqueous solution of nitric acid) with a mass concentration of 68% to 50g (i.e. 2.78mol) of water, and fully dissolve to obtain a clear and transparent solution, which is the acid solution;

[0076] S3, adding the mixed powder in S1 to the acid solution in S2, mixing, and obtaining a wet powder;

[0077] S4, drying the wet powder in S3 at 100°C for 12 hours, and then calcining at 700°C for 2 hours to obtain dodecaluminate heptahedralite having a cage structure;

[0078] S5, mixing 75 g of calcium heptaaluminate having a cage structure in S4 and 25 g of ZnO to obtain a mixture;

[0079] S6, adding 50 g of 10% by mass KOH aqueous solution to the mixture in S5, kneading to obtain a plastic dough;

[0080] S7, placing the plastic dough in a mold (the mold is a hollow cylindrical shape with an inner diameter of 4 mm) to form a strip-shaped object, drying it at 150° C. for 2 h, and then calcining it at 500° C. for 2 h to obtain a catalyst carrier;

[0081] S8, after mixing 5g ZnO and 6g ammonium carbonate, add 15mL of 25% ammonia water, stir, and obtain an impregnation solution;

[0082] S9. Add 45 g of the catalyst carrier prepared in step S7 to the impregnation solution obtained in S8, stir and place for 15 hours, and then dry at 180° C. for 12 hours to obtain a zinc oxide desulfurizer.

[0083] Example 2

[0084] The present invention provides a method for preparing a zinc oxide desulfurizer, comprising the following steps:

[0085] S1, 0.85714 mol of calcium hydroxide powder and 1 mol of pseudo-boehmite powder are mixed to obtain a mixed powder (the molar ratio of aluminum to calcium in the mixed powder is 7:6);

[0086] S2, add 5g of nitric acid (aqueous solution of nitric acid) with a mass concentration of 68% to 50g (i.e. 2.78mol) of water, and fully dissolve to obtain a clear and transparent solution, which is the acid solution;

[0087] S3, adding the mixed powder in S1 to the acid solution in S2, mixing, and obtaining a wet powder;

[0088] S4, drying the wet powder in S3 at 120°C for 4 hours, and then calcining at 650°C for 2 hours to obtain dodecaluminate heptahedralite having a cage structure;

[0089] S5, mixing 75 g of calcium heptaaluminate having a cage structure in S4 and 25 g of ZnO to obtain a mixture;

[0090] S6, adding 50 g of 10% by mass KOH aqueous solution to the mixture in S5, kneading to obtain a plastic dough;

[0091] S7, placing the plastic dough in a mold (the mold is a hollow cylindrical shape with an inner diameter of 4 mm) and forming it into a strip-shaped object, drying it at 120° C. for 4 h, and then calcining it at 450° C. for 2 h to obtain a catalyst carrier;

[0092] S8, after mixing 5g ZnO and 6g ammonium carbonate, add 15mL of 25% ammonia water, stir, and obtain an impregnation solution;

[0093] S9. Add 45 g of the catalyst carrier prepared in step S7 to the impregnation solution obtained in S8, stir and place for 15 hours, and then dry at 200° C. for 4 hours to obtain a zinc oxide desulfurizer.

[0094] Example 3

[0095] The present invention provides a method for preparing a zinc oxide desulfurizer, comprising the following steps:

[0096] S1, 0.85714 mol of calcium hydroxide powder and 1 mol of pseudo-boehmite powder are mixed to obtain a mixed powder (the molar ratio of aluminum to calcium in the mixed powder is 7:6);

[0097] S2, add 5g of nitric acid (aqueous solution of nitric acid) with a mass concentration of 68% to 50g (i.e. 2.78mol) of water, and fully dissolve to obtain a clear and transparent solution, which is the acid solution;

[0098] S3, adding the mixed powder in S1 to the acid solution in S2, mixing, and obtaining a wet powder;

[0099] S4, drying the wet powder in S3 at 150°C for 2 hours, and then calcining at 600°C for 4 hours to obtain dodecaluminate heptahedralite having a cage structure;

[0100] S5, mixing 70 g of calcium heptaaluminate having a cage structure in S4 and 30 g of ZnO to obtain a mixture;

[0101] S6, adding 30 g of 10% by mass KOH aqueous solution to the mixture in S5, kneading to obtain a plastic dough;

[0102] S7, placing the plastic dough in a mold (the mold is a hollow cylindrical shape with an inner diameter of 4 mm) to form a strip-shaped object, drying it at 100° C. for 12 h, and then calcining it at 400° C. for 4 h to obtain a catalyst carrier;

[0103] S8, after mixing 5g ZnO and 6g ammonium carbonate, add 15mL of 25% ammonia water, stir, and obtain an impregnation solution;

[0104] S9. Add 45 g of the catalyst carrier prepared in step S7 to the impregnation solution obtained in S8, stir and place for 15 hours, and then dry at 250° C. for 2 hours to obtain a zinc oxide desulfurizer.

[0105] Example 4

[0106] The present invention provides a method for preparing a zinc oxide desulfurizer, comprising the following steps:

[0107] S1, 0.85714 mol of calcium hydroxide powder and 1 mol of pseudo-boehmite powder are mixed to obtain a mixed powder (the molar ratio of aluminum to calcium in the mixed powder is 7:6);

[0108] S2, add 5g of nitric acid (aqueous solution of nitric acid) with a mass concentration of 68% to 50g (i.e. 2.78mol) of water, and fully dissolve to obtain a clear and transparent solution, which is the acid solution;

[0109] S3, adding the mixed powder in S1 to the acid solution in S2, mixing, and obtaining a wet powder;

[0110] S4, drying the wet powder in S3 at 120°C for 4 hours, and then calcining at 600°C for 4 hours to obtain dodecaluminate heptahedralite having a cage structure;

[0111] S5, mixing 90 g of calcium dodecaaluminate having a cage structure in S4 and 10 g of ZnO to obtain a mixture;

[0112] S6, adding 25 g of a 10% by mass KOH aqueous solution and 25 g of a 10% by mass NaOH aqueous solution to the mixture in S5, kneading to obtain a plastic dough;

[0113] S7, placing the plastic dough in a mold (the mold is a hollow cylindrical shape with an inner diameter of 4 mm) and forming it into a strip-shaped object, drying it at 120° C. for 4 h, and then calcining it at 450° C. for 3 h to obtain a catalyst carrier;

[0114] S8, after mixing 5g ZnO and 6g ammonium carbonate, add 15mL of 25% ammonia water, stir, and obtain an impregnation solution;

[0115] S9. Add 45 g of the catalyst carrier prepared in step S7 to the impregnation solution obtained in S8, stir and place for 15 hours, and then dry at 220° C. for 3 hours to obtain a zinc oxide desulfurizer.

[0116] Example 5

[0117] The present invention provides a method for preparing a zinc oxide desulfurizer, comprising the following steps:

[0118] S1, 0.85714 mol of calcium hydroxide powder and 1 mol of pseudo-boehmite powder are mixed to obtain a mixed powder (the molar ratio of aluminum to calcium in the mixed powder is 7:6);

[0119] S2, add 5g of nitric acid (aqueous solution of nitric acid) with a mass concentration of 68% to 50g (i.e. 2.78mol) of water, and fully dissolve to obtain a clear and transparent solution, which is the acid solution;

[0120] S3, adding the mixed powder in S1 to the acid solution in S2, mixing, and obtaining a wet powder;

[0121] S4, drying the wet powder in S3 at 120°C for 4 hours, and then calcining at 600°C for 4 hours to obtain dodecaluminate heptahedralite having a cage structure;

[0122] S5, mixing 70 g of calcium heptaaluminate having a cage structure in S4 and 30 g of ZnO to obtain a mixture;

[0123] S6, adding 50 g of 10% by mass KOH aqueous solution to the mixture in S5, kneading to obtain a plastic dough;

[0124] S7, placing the plastic dough in a mold (the mold is a hollow cylindrical shape with an inner diameter of 4 mm) and forming it into a strip-shaped object, drying it at 120° C. for 4 h, and then calcining it at 450° C. for 2 h to obtain a catalyst carrier;

[0125] S8, after mixing 5g ZnO and 6g ammonium carbonate, add 15mL of 25% ammonia water, stir, and obtain an impregnation solution;

[0126] S9. Add 45 g of the catalyst carrier prepared in step S7 to the impregnation solution obtained in S8, stir and place for 15 hours, and then dry at 200° C. for 4 hours to obtain a zinc oxide desulfurizer.

[0127] Example 6

[0128] The present invention provides a method for preparing a zinc oxide desulfurizer, comprising the following steps:

[0129] S1, 0.85714 mol of calcium hydroxide powder and 1 mol of pseudo-boehmite powder are mixed to obtain a mixed powder (the molar ratio of aluminum to calcium in the mixed powder is 7:6);

[0130] S2, add 5g of nitric acid (aqueous solution of nitric acid) with a mass concentration of 68% to 50g (i.e. 2.78mol) of water, and fully dissolve to obtain a clear and transparent solution, which is the acid solution;

[0131] S3, adding the mixed powder in S1 to the acid solution in S2, mixing, and obtaining a wet powder;

[0132] S4, drying the wet powder in S3 at 120°C for 4 hours, and then calcining at 650°C for 2 hours to obtain dodecaluminate heptahedralite having a cage structure;

[0133] S5, mixing 80 g of calcium heptaaluminate having a cage structure in S4 and 20 g of ZnO to obtain a mixture;

[0134] S6, adding 50 g of 10% by mass KOH aqueous solution to the mixture in S5, kneading to obtain a plastic dough;

[0135] S7, placing the plastic dough in a mold (the mold is a hollow cylindrical shape with an inner diameter of 4 mm) and forming it into a strip-shaped object, drying it at 120° C. for 4 h, and then calcining it at 450° C. for 2 h to obtain a catalyst carrier;

[0136] S8, after mixing 5g ZnO and 6g ammonium carbonate, add 15mL of 25% ammonia water, stir, and obtain an impregnation solution;

[0137] S9. Add 45 g of the catalyst carrier prepared in step S7 to the impregnation solution obtained in S8, stir and place for 15 hours, and then dry at 200° C. for 4 hours to obtain a zinc oxide desulfurizer.

[0138] Example 7

[0139] The present invention provides a method for preparing a zinc oxide desulfurizer, comprising the following steps:

[0140] S1, 0.85714 mol of calcium hydroxide powder and 1 mol of pseudo-boehmite powder are mixed to obtain a mixed powder (the molar ratio of aluminum to calcium in the mixed powder is 7:6);

[0141] S2, add 5g of nitric acid (aqueous solution of nitric acid) with a mass concentration of 68% to 50g (i.e. 2.78mol) of water, and fully dissolve to obtain a clear and transparent solution, which is the acid solution;

[0142] S3, adding the mixed powder in S1 to the acid solution in S2, mixing, and obtaining a wet powder;

[0143] S4, drying the wet powder in S3 at 120°C for 4 hours, and then calcining at 650°C for 2 hours to obtain dodecaluminate heptahedralite having a cage structure;

[0144] S5, mixing 85 g of calcium heptaaluminate having a cage structure in S4 and 15 g of ZnO to obtain a mixture;

[0145] S6, adding 50 g of 10% by mass KOH aqueous solution to the mixture in S5, kneading to obtain a plastic dough;

[0146] S7, placing the plastic dough in a mold (the mold is a hollow cylindrical shape with an inner diameter of 4 mm) and forming it into a strip-shaped object, drying it at 120° C. for 4 h, and then calcining it at 450° C. for 2 h to obtain a catalyst carrier;

[0147] S8, after mixing 5g ZnO and 6g ammonium carbonate, add 15mL of 25% ammonia water, stir, and obtain an impregnation solution;

[0148] S9. Add 45 g of the catalyst carrier prepared in step S7 to the impregnation solution obtained in S8, stir and place for 15 hours, and then dry at 200° C. for 4 hours to obtain a zinc oxide desulfurizer.

[0149] Example 8

[0150] The present invention provides a method for preparing a zinc oxide desulfurizer, comprising the following steps:

[0151] S1, 0.85714 mol of calcium hydroxide powder and 1 mol of pseudo-boehmite powder are mixed to obtain a mixed powder (the molar ratio of aluminum to calcium in the mixed powder is 7:6);

[0152] S2, add 5g of nitric acid (aqueous solution of nitric acid) with a mass concentration of 68% to 50g (i.e. 2.78mol) of water, and fully dissolve to obtain a clear and transparent solution, which is the acid solution;

[0153] S3, adding the mixed powder in S1 to the acid solution in S2, mixing, and obtaining a wet powder;

[0154] S4, drying the wet powder in S3 at 120°C for 4 hours, and then calcining at 650°C for 2 hours to obtain dodecaluminate heptahedralite having a cage structure;

[0155] S5, mixing 75 g of calcium heptaaluminate having a cage structure in S4 and 25 g of ZnO to obtain a mixture;

[0156] S6, adding 50 g of 10% by mass KOH aqueous solution to the mixture in S5, kneading to obtain a plastic dough;

[0157] S7, placing the plastic dough in a mold (the mold is a hollow cylindrical shape with an inner diameter of 4 mm) and forming it into a strip-shaped object, drying it at 120° C. for 4 h, and then calcining it at 450° C. for 2 h to obtain a catalyst carrier;

[0158] S8, after mixing 4 g ZnO and 4.8 g ammonium carbonate, add 15 mL of 25% ammonia water, stir, and obtain an impregnation solution;

[0159] S9. Add 46 g of the catalyst carrier prepared in step S7 to the impregnation solution obtained in S8, stir and place for 15 hours, and then dry at 200° C. for 4 hours to obtain a zinc oxide desulfurizer.

[0160] Example 9

[0161] The present invention provides a method for preparing a zinc oxide desulfurizer, comprising the following steps:

[0162] S1, 0.85714 mol of calcium hydroxide powder and 1 mol of pseudo-boehmite powder are mixed to obtain a mixed powder (the molar ratio of aluminum to calcium in the mixed powder is 7:6);

[0163] S2, add 5g of nitric acid (aqueous solution of nitric acid) with a mass concentration of 68% to 50g (i.e. 2.78mol) of water, and fully dissolve to obtain a clear and transparent solution, which is the acid solution;

[0164] S3, adding the mixed powder in S1 to the acid solution in S2, mixing, and obtaining a wet powder;

[0165] S4, drying the wet powder in S3 at 120°C for 4 hours, and then calcining at 650°C for 2 hours to obtain dodecaluminate heptahedralite having a cage structure;

[0166] S5, mixing 75 g of calcium heptaaluminate having a cage structure in S4 and 25 g of ZnO to obtain a mixture;

[0167] S6, adding 50 g of 10% by mass KOH aqueous solution to the mixture in S5, kneading to obtain a plastic dough;

[0168] S7, placing the plastic dough in a mold (the mold is a hollow cylindrical shape with an inner diameter of 4 mm) to form a strip-shaped object, drying it at 150° C. for 2 h, and then calcining it at 500° C. for 2 h to obtain a catalyst carrier;

[0169] S8, after mixing 2.5 g ZnO and 3.0 g ammonium carbonate, add 16 mL of 25% ammonia water, stir, and obtain an impregnation solution;

[0170] S9. Add 47.5 g of the catalyst carrier prepared in step S7 to the impregnation solution obtained in S8, stir and place for 15 hours, and then dry at 200° C. for 4 hours to obtain a zinc oxide desulfurizer.

[0171] Example 10

[0172] The present invention provides a method for preparing a zinc oxide desulfurizer, comprising the following steps:

[0173] S1, 0.85714 mol of calcium hydroxide powder and 1 mol of pseudo-boehmite powder are mixed to obtain a mixed powder (the molar ratio of aluminum to calcium in the mixed powder is 7:6);

[0174] S2, add 5g of nitric acid (aqueous solution of nitric acid) with a mass concentration of 68% to 50g (i.e. 2.78mol) of water, and fully dissolve to obtain a clear and transparent solution, which is the acid solution;

[0175] S3, adding the mixed powder in S1 to the acid solution in S2, mixing, and obtaining a wet powder;

[0176] S4, drying the wet powder in S3 at 120°C for 4 hours, and then calcining at 650°C for 2 hours to obtain dodecaluminate heptahedralite having a cage structure;

[0177] S5, mixing 75 g of dodecaaluminate heptaaluminate having a cage structure in S4 and 25 g of ZnO to obtain a mixture;

[0178] S6, adding 50 g of 10% by mass KOH aqueous solution to the mixture in S5, kneading to obtain a plastic dough;

[0179] S7, placing the plastic dough in a mold (the mold is a hollow cylindrical shape with an inner diameter of 4 mm) and forming it into a strip-shaped object, drying it at 120° C. for 4 h, and then calcining it at 450° C. for 2 h to obtain a catalyst carrier;

[0180] S8, after mixing 1.0 g ZnO and 2.0 g ammonium carbonate, add 16 mL of 25% ammonia water, stir, and obtain an impregnation solution;

[0181] S9. Add 49.0 g of the catalyst carrier prepared in step S7 to the impregnation solution obtained in S8, stir and place for 15 hours, and then dry at 200° C. for 4 hours to obtain a zinc oxide desulfurizer.

[0182] Comparative Example 1

[0183] This comparative example provides a method for preparing a room temperature fine desulfurizer, comprising the following steps:

[0184] S1. Add 9 mL of tetraethyl orthosilicate (TEOS), 7 mL of anhydrous ethanol, 1.1 mL of deionized water, and 0.3 mL of dilute nitric acid (4 mol / L) into a 100 mL beaker and stir magnetically at room temperature for 60 min to obtain a silica sol.

[0185] S2. Weigh 11.9 g zinc nitrate, 8 mL methanol and 12 mL ethylene glycol, place in a beaker, and stir to form a zinc nitrate solution;

[0186] S3, slowly adding the prepared zinc nitrate solution to the prepared silica sol, and continuing stirring for 60 minutes to form a mixed sol;

[0187] S4. Place the mixed sol in a vacuum oven, set the chamber temperature to 30°C, and age for 10 hours; then raise the temperature to 120°C for gelation and drying for 12 hours; place the dried gel in a quartz container, and then place it in a muffle furnace, turn on the heater, raise the temperature to 300°C, maintain this temperature for 120 minutes, and the heating rate is 1°C / min, then continue to raise the temperature to 500°C, maintain this temperature for 120 minutes, and after calcination, allow it to cool naturally to room temperature. The product is the prepared room temperature zinc oxide fine desulfurizer particles.

[0188] Performance Testing

[0189] The activity and strength of the zinc oxide desulfurizers prepared in Examples 1 to 10 and the room temperature fine desulfurizer prepared in Comparative Example 1 (Comparative Example 1 was not formed and no strength test was performed) and other properties were tested.

[0190] The catalyst strength test is measured on an intelligent strength meter using a lateral pressure strength meter.

[0191] The desulfurization performance test was carried out in a quartz glass reaction tube with a diameter of 28 mm. The zinc oxide desulfurizer prepared in Examples 1 to 10 and the room temperature fine desulfurizer prepared in Comparative Example 1 were cut into particles with a height-to-diameter ratio of approximately 1 (the specific catalyst was cut into a cylindrical shape with a diameter of 4 mm and a height of 4 mm), respectively, and placed in a quartz glass reaction tube. Gas was introduced, and the gas included H2, N2, and H2S. The concentration of H2S in the gas was 1000 ppm, the volume fraction of H2 was 25%, and the rest was N2; the volume space velocity was 2000 h -1 , reaction temperature is 30℃, outlet H2S≤0.01ppm; sulfur capacity is analyzed according to HG / T2513-2014. The results are shown in Table 2.

[0192] Table 2 - Activity test results of zinc oxide desulfurizer

[0193] Example Compressive strength(N / cm) <![CDATA[Space velocity (h -1 )]]> Reaction temperature (℃) Sulfur capacity (%) Example 1 93 2000 30 10.8 Example 2 96 2000 30 12.6 Example 3 91 2000 30 10.9 Example 4 93 2000 30 7.7 Example 5 88 2000 30 10.1 Example 6 89 2000 30 9.5 Example 7 91 2000 30 9.0 Example 8 93 2000 30 12.1 Example 9 89 2000 30 8.8 Example 10 84 2000 30 3.2 Comparative Example 1 / 2000 30 2.7

[0194] It can be seen from Table 2 that, under the premise of satisfying the outlet H2S ≤ 0.01ppm, the sulfur capacity of the zinc oxide desulfurizer prepared in Examples 1 to 8 is significantly higher than that of the room temperature fine desulfurizer prepared in Comparative Example 1, with the highest sulfur capacity reaching 12.6% (Example 2), and the preparation process is much simpler. With the increase of the impregnation ZnO content, the sulfur capacity increases significantly, and the crushing strength gradually increases, showing a significant correlation. With the increase of the mixed addition ZnO content, the crushing strength shows a gradual decreasing trend. It is well known that improving the crushing strength is beneficial to reducing the resistance of the catalyst bed in industrial production, reducing the power consumption in industrial production, and extending the service life of the catalyst. The above data show that the desulfurizer and its preparation method proposed in the present invention have significant advantages.

[0195] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a zinc oxide desulfurizer, characterized in that: The following steps are involved: mixing dodecaluminate heptaaluminate and zinc oxide to obtain a mixture; adding an alkaline solution to the mixture and kneading to obtain a plastic dough; The plastic dough is dried and then calcined to obtain a catalyst carrier; After mixing ZnO and ammonium carbonate, adding ammonia water and stirring to obtain an impregnation solution; The catalyst carrier is added into the impregnation solution, stirred and then dried to obtain a zinc oxide desulfurizer.

2. The method for preparing a zinc oxide desulfurizing agent according to claim 1, characterized in that: The plastic dough is dried at 100-150°C for 2-12 hours, and then calcined at 400-500°C for 2-4 hours to obtain a catalyst carrier.

3. The method for preparing the zinc oxide desulfurizer according to claim 1, characterized in that: The catalyst carrier is added to the impregnation solution, stirred, and dried at 180-250° C. for 2-12 hours to obtain a zinc oxide desulfurizer.

4. The method for preparing a zinc oxide desulfurizing agent according to claim 1, characterized in that: The alkaline solution includes an aqueous NaOH solution and / or an aqueous KOH solution; The mass concentration of the alkaline solution is 10-20%.

5. The method for preparing the zinc oxide desulfurizing agent according to claim 1, characterized in that: Dodecalcium heptaaluminate and zinc oxide are mixed to obtain a mixture, and in the step of adding an alkaline solution to the mixture, the mass ratio of dodecalcium heptaaluminate, zinc oxide, and alkaline solution is (70-90):(10-30):(25-50).

6. The method for preparing the zinc oxide desulfurizer according to claim 1, characterized in that: After mixing ZnO and ammonium carbonate, adding ammonia water, stirring to obtain an impregnation solution, and adding the catalyst support to the impregnation solution, the mass volume ratio of ZnO, ammonium carbonate, catalyst support, and ammonia water is (1-5) g: (2-6) g: (45-49) g: (15-16) mL; The mass concentration of the ammonia water is 20-25%.

7. The method for preparing the zinc oxide desulfurizer according to claim 1, characterized in that: The preparation method of dodecalcium heptaaluminate comprises the following steps: Mixing an aluminum source and a calcium source to obtain a mixed powder; Add nitric acid to water to obtain an acid solution; Adding the mixed powder into the acid solution and mixing to obtain a wet powder; The wet powder is dried at 100-150°C for 2-12 hours, and then calcined at 600-700°C for 2-4 hours to obtain dodecaluminate heptaaluminate having a cage structure; The aluminum source is pseudo-boehmite; The calcium source is calcium hydroxide; The molar ratio of aluminum in the aluminum source to calcium in the calcium source is 7:6; In the step of adding nitric acid to water, the nitric acid is a nitric acid solution with a mass fraction of 65-68%, and the mass ratio of the nitric acid solution to water is (3-5):(48-50); In the steps of mixing an aluminum source and a calcium source to obtain a mixed powder and adding nitric acid into water, the molar ratio of aluminum in the aluminum source to water is 1:(2.67-2.78).

8. A zinc oxide desulfurizer, characterized in that: The preparation method is as described in any one of claims 1 to 7.

9. Use of the zinc oxide desulfurizer prepared by the preparation method according to any one of claims 1 to 7 or the zinc oxide desulfurizer according to claim 8 in removing sulfides from raw gas.

10. The use according to claim 9, characterized in that The use conditions of the zinc oxide desulfurizer are: reaction temperature is 20-30°C, space velocity is 500-2000h -1 .

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