Molecular sieve adsorption desulfurizer for acid gas and preparation method of molecular sieve adsorption desulfurizer

Abstract

The invention provides a molecular sieve adsorption desulfurizer for acid gas and a preparation method thereof, the molecular sieve adsorption desulfurizer comprises the following raw materials: 8-12wt% of porous zeolite, 18-22wt% of hydrotalcite and 65-75wt% of hydroxide, and the preparation method comprises the following steps: grinding and uniformly mixing the raw materials in proportion to obtain mixed particles, and drying the obtained mixture particles at 100-120 DEG C, putting the dried particles into a muffle furnace, and roasting at 350-550 DEG C for 6-10 hours to obtain the molecular sieve adsorption desulfurizer. The molecular sieve adsorption desulfurizer provided by the invention can improve the adsorption desulfurization efficiency, further modifies zeolite through a specific preparation mode, can improve the diffusion performance of zeolite pore channels and improve the accessibility of active sites, so that macromolecular sulfides are diffused, the reaction activity and stability are enhanced, and the molecular sieve adsorption desulfurizer has a relatively good application value.

Description

Technical Field

[0001] The present invention relates to the technical field of gas adsorbents, and particularly relates to a molecular sieve adsorbent desulfurizer for acidic gases and a preparation method thereof. Background Art

[0002] Semiconductors require the use of a large amount of acids, alkalis, organic solvents and various special gases in processes such as cleaning, lithography, degluing, and drying. The entire production process generates a large amount and variety of three wastes. The crystal growth and wafer preparation stages in semiconductor device manufacturing are the manufacturing processes of integrated circuits, and a large amount of waste gas generated in semiconductor production originates from the manufacturing of integrated circuits.

[0003] In the semiconductor industry, acidic waste gas comes from cleaning, sputtering, wet etching, wet degluing and process waste gas after Local Scrubber treatment. Its main components are HF, HCl, Cl2, H2SO4, SO2, etc. If these gases are discharged without being well treated, it will deteriorate the atmospheric environment, affect human health, and cause public nuisance events of environmental pollution.

[0004] Adsorption desulfurization is an important means of effective desulfurization in recent years. Currently, the adsorbents used in adsorption desulfurization mainly include metal oxides, zeolite molecular sieves, mesoporous materials, MOFs and activated carbon. They have their own advantages and uses, but there are also various problems. Metal oxides are easy to prepare, have good structural stability and high sulfur selectivity, but their sulfur capacity is small, they are difficult to regenerate and are not environmentally friendly; mesoporous materials have high adsorption selectivity for macromolecular sulfides, large specific surface area and pore volume, but their adsorption capacity is weak and their stability is poor; MOFs have a variety of topological structures, adjustable pore size and are easy to modify, but their regenerability and reusability are poor, they are unstable at high temperatures and have poor mechanical strength; activated carbon has surface active groups, but its stability is poor and it is difficult to regenerate. Among the adsorbents, zeolite molecular sieve is an adsorbent that is easy to regenerate, has a large specific surface area and good metal exchangeability, but there will be problems such as limited diffusion of macromolecular sulfides in zeolite and small pore size of zeolite during use, which affects the adsorption desulfurization efficiency. Summary of the Invention

[0005] Aiming at the existing technical problems, the purpose of the present invention is to provide a molecular sieve adsorbent desulfurizer and a preparation method thereof. The molecular sieve adsorbent desulfurizer provided by the present invention can improve the adsorption desulfurization efficiency. Further, by modifying the zeolite through a specific preparation method, the diffusion performance of the zeolite pores can be improved, the accessibility of the active sites can be increased, so that macromolecular sulfides can diffuse, and the reaction activity and stability can be enhanced.

[0006] In order to achieve the above object, the technical scheme adopted by the present invention is as follows:

[0007] On the one hand, the present invention provides a molecular sieve adsorbent desulfurizer for acidic gases, comprising the following raw materials: 8-12 wt% of porous zeolite, 18-22 wt% of hydrotalcite, and 65-75 wt% of hydroxide.

[0008] In some embodiments, the synthesis steps of the porous zeolite are as follows:

[0009] (1) Mix the silica-alumina zeolite and the basic compound evenly to obtain a mixture;

[0010] (2) Stir the mixture obtained in step (1) in a constant temperature water bath at 60-90 °C for 1-3 hours, and then centrifuge and filter;

[0011] (3) Wash the filter cake to neutral, dry it and put it into a muffle furnace, and calcine it at 500-600 °C for 4-8 hours to obtain the porous zeolite.

[0012] Preferably, the synthesis steps of the porous zeolite are as follows:

[0013] (1) Mix the silica-alumina zeolite and the basic compound evenly to obtain a mixture;

[0014] (2) Stir the mixture obtained in step (1) in a constant temperature water bath at 80 °C for 2 hours, and then centrifuge and filter;

[0015] (3) Wash the filter cake to neutral, dry it and put it into a muffle furnace, and calcine it at 550 °C for 6 hours.

[0016] In some embodiments, the particle size range of the silica-alumina zeolite is 10-70 mesh.

[0017] Preferably, the particle size range of the silica-alumina zeolite is 50-60 mesh.

[0018] More preferably, the silica-alumina ratio of the silica-alumina zeolite is 5-25.

[0019] In some embodiments, the mass ratio of the silica-alumina zeolite to the basic compound is 1:(6-10).

[0020] Preferably, the mass ratio of the silica-alumina zeolite to the basic compound is 1:8.

[0021] For common zeolites on the market, there are usually problems such as small pore sizes during use, limited diffusion of macromolecular sulfides, and impact on the adsorption desulfurization efficiency. The porous zeolite formed by modifying the zeolite proposed in this application can effectively improve the adsorption desulfurization efficiency. On the one hand, zeolites with a low silica-alumina ratio have good hydrophilicity and adsorption properties. An excessively high silica-alumina ratio will affect the electrostatic field inside the porous zeolite, thereby affecting the adsorption effect. On the other hand, the internal surface area of silica-alumina zeolite is much larger than the external surface area. Due to its huge internal surface area, silica-alumina zeolite has high adsorption performance. The smaller the particle size, the larger the total specific surface area and the external surface area. However, the increase in the internal surface area caused by the continuous reduction of the particle size is very limited, and the improvement effect on the adsorption performance will not be very obvious. In addition, as the amount of the alkaline compound increases to a certain extent, the increase in the solubility of the zeolite caused by the increase in the alkaline compound is limited, thereby affecting the modification effect of the porous zeolite. Considering the diffusion rate of the adsorbed substance, the crushing power consumption and loss of silica-alumina zeolite, and the preparation cost of the porous zeolite, this application further regulates the silica-alumina ratio of the silica-alumina zeolite to be 5-25, the particle size of the silica-alumina zeolite to be 50-60 mesh, and the mass ratio of the silica-alumina zeolite to the alkaline compound to be 1:(6-10), so that the specific surface area of the obtained porous zeolite is significantly increased, the layered structure is more obvious, and the adsorption desulfurization effect is more significant.

[0022] In some embodiments, the alkaline compound used for synthesizing the porous zeolite is a strong organic base.

[0023] In some embodiments, the strong organic base is selected from dodecyltrimethylammonium hydroxide or tetradecyltrimethylammonium hydroxide.

[0024] Regarding the alkaline compound used in the synthesis of the porous zeolite, the prior art usually uses an inorganic base to react with the zeolite to achieve desilication modification. However, the addition of the inorganic base requires an additional ion exchange step to form the porous zeolite, while this application selects a strong organic base to avoid the ion exchange step required during preparation, saving reaction time and reaction cost.

[0025] In the strong organic bases, dodecyltrimethylammonium hydroxide and tetradecyltrimethylammonium hydroxide have good compatibility and biodegradability, and can be completely decomposed at a relatively low temperature, which is beneficial for their application in the electron etching of semiconductors.

[0026] In some embodiments, the hydroxide is one or more of magnesium hydroxide, calcium hydroxide, potassium hydroxide, and sodium hydroxide.

[0027] Preferably, the hydroxide is a combination of magnesium hydroxide and calcium hydroxide, and the mass ratio of the two is 1:2.

[0028] For many adsorbents on the market for acidic gases, adding a certain amount of calcium oxide for reaction can achieve the removal effect. However, for the treatment of the same amount of waste gas, the demand for calcium oxide is much higher than that of calcium hydroxide. In this application, by adding a certain amount of hydroxide, the input of raw materials can be reduced while adsorbing desulfurization, saving the treatment cost. In particular, the applicant found that using magnesium hydroxide and calcium hydroxide with a mass ratio of 1:2 can help enhance the adsorption desulfurization effect.

[0029] In some embodiments, the hydrotalcite is a divalent cation Ni 2+ / Mg 2+ and a trivalent cation Al 3+ / Ti 3+ composed of a binary compound. The large specific surface area and porosity of hydrotalcite endow it with a large adsorption surface and storage space. It can adsorb a large amount of gas, store the gas in its pores, or react with other substances on its surface.

[0030] Preferably, the molar ratio of the divalent cation to the trivalent cation is (2-5):1, and the specific surface area of the hydrotalcite is 8-14m 2 / g.

[0031] Preferably, the hydrotalcite is magnesium-aluminum hydrotalcite, and the magnesium-aluminum molar ratio of magnesium-aluminum hydrotalcite is 4.21, and the specific surface area is 10.1m 2 / g. Magnesium-aluminum hydrotalcite can be purchased from common manufacturers on the market, including but not limited to Hubei Xinyuhong Biomedical Technology Co., Ltd.

[0032] In some embodiments, the molecular sieve adsorbent for desulfurization further contains 0.2-0.4wt% of titanium dioxide. Adding titanium dioxide increases the specific surface area of the obtained molecular sieve adsorbent for desulfurization, enhances the ability of mass exchange, is conducive to improving the adsorption desulfurization efficiency, and further deodorizes and purifies the air.

[0033] Preferably, the crystal phase of titanium dioxide is the rutile phase {110} plane. The rutile phase has good crystallinity and stable structure. At the same time, compared with the common rutile phase {111} plane on the market, the rutile phase {110} plane has a better specific surface area, which is conducive to improving the adsorption efficiency.

[0034] On the other hand, the present invention provides a preparation method of a molecular sieve adsorbent for desulfurization, comprising the following steps:

[0035] S1. Grind and mix porous zeolite, hydrotalcite, and hydroxide in proportion to obtain mixed particles;

[0036] S2. Dry the mixture particles obtained in step S1 at 100-120°C;

[0037] S3. Put the dried particles obtained in step S2 into a muffle furnace and calcine them at 350 - 550 °C for 6 - 10 hours to obtain the molecular sieve adsorbent for desulfurization.

[0038] Advantages:

[0039] The present invention provides a molecular sieve adsorbent for desulfurization and its preparation method. The molecular sieve adsorbent for desulfurization can improve the desulfurization efficiency by adsorption. Further, by modifying the zeolite through a specific preparation method, the diffusion performance of the zeolite pores can be improved, the accessibility of the active sites can be enhanced, enabling the diffusion of macromolecular sulfides, and enhancing the reaction activity and stability. Specific Embodiments

[0040] The following will illustrate the present invention in conjunction with specific implementation examples. It should be noted that the following examples are examples of the present invention, only used to illustrate the present invention, rather than to limit the present invention. Other combinations and various improvements within the concept of the present invention can be made without departing from the main idea or scope of the present invention.

[0041] For the convenience of those skilled in the art to implement the present invention, the manufacturers of some raw materials in the examples and comparative examples are described as follows:

[0042] Silicoaluminophosphate zeolite: purchased from Zhuoran Environmental Protection Technology (Dalian) Co., Ltd.;

[0043] Magnesium aluminum hydrotalcite: purchased from Hubei Xinyuhong Biomedical Technology Co., Ltd., where the molar ratio of magnesium to aluminum is 4.21 and the specific surface area is 10.1 m 2 / g;

[0044] Titanium dioxide with rutile phase {110} plane: purchased from Dihedral (Shanghai) Technology Co., Ltd.;

[0045] Anatase phase titanium dioxide: purchased from Nantong Runfeng Petrochemical Co., Ltd.;

[0046] For other materials, without special instructions, they can all be purchased from the market.

[0047] Example 1

[0048] A molecular sieve adsorbent for acidic gases, which comprises the following raw materials: 8 wt% of porous zeolite, 20 wt% of magnesium aluminum hydrotalcite, 48 wt% of calcium hydroxide, and 24 wt% of magnesium hydroxide.

[0049] The synthesis steps of the porous zeolite are as follows:

[0050] (1) Mix the silicoaluminophosphate zeolite and dodecyltrimethylammonium hydroxide evenly at a mass ratio of 1:8 to obtain a mixture;

[0051] (2) Stir the mixture obtained in step (1) in a constant temperature water bath at 80 °C for 2 hours and then centrifuge and filter it;

[0052] (3) Wash the filter cake to neutral, dry it and put it into a muffle furnace, and calcine it at 550 °C for 6 hours to obtain the porous zeolite.

[0053] Among them, in step (1), the silica-alumina ratio of the silica-alumina zeolite is 15 and the particle size is 60 mesh.

[0054] The preparation method of the molecular sieve adsorbent desulfurizer in this example includes the following steps:

[0055] S1. Grind and mix the porous zeolite, magnesium-aluminum hydrotalcite, calcium hydroxide, and magnesium hydroxide evenly in proportion to obtain mixed particles;

[0056] S2. Dry the mixed particles obtained in step S1 at 120 °C;

[0057] S3. Put the dried particles obtained in step S2 into a muffle furnace and calcine them at 450 °C for 8 hours to obtain the adsorbent desulfurizer.

[0058] Example 2

[0059] A molecular sieve adsorbent desulfurizer for acidic gases, which comprises the following raw materials: 12 wt% of porous zeolite, 22 wt% of magnesium-aluminum hydrotalcite, 44 wt% of calcium hydroxide, and 22 wt% of magnesium hydroxide.

[0060] Among them, the synthesis steps of the porous zeolite are as follows:

[0061] (1) Mix the silica-alumina zeolite and dodecyltrimethylammonium hydroxide evenly at a mass ratio of 1:6 to obtain a mixture;

[0062] (2) Stir the mixture obtained in step (1) in a constant temperature water bath at 80 °C for 2 hours and then centrifuge and filter it;

[0063] (3) Wash the filter cake to neutral, dry it and put it into a muffle furnace, and calcine it at 550 °C for 6 hours to obtain the porous zeolite.

[0064] Among them, in step (1), the silica-alumina ratio of the silica-alumina zeolite is 25 and the particle size is 50 mesh.

[0065] The preparation method of the molecular sieve adsorbent desulfurizer in this example is the same as that in Example 1.

[0066] Example 3

[0067] A molecular sieve adsorbent desulfurizer for acidic gases, which comprises the following raw materials: 10 wt% of porous zeolite, 18 wt% of magnesium-aluminum hydrotalcite, 48 wt% of calcium hydroxide, and 24 wt% of magnesium hydroxide.

[0068] The synthesis steps of the porous zeolite are as follows:

[0069] (1) Mix silica-alumina zeolite and tetradecyltrimethylammonium hydroxide evenly at a mass ratio of 1:8 to obtain a mixture;

[0070] (2) Stir the mixture obtained in step (1) in a constant temperature water bath at 80 °C for 2 hours and then centrifuge and filter;

[0071] (3) Wash the filter cake to neutral, dry it and put it into a muffle furnace, and calcine it at 550 °C for 6 hours to obtain the porous zeolite.

[0072] Among them, in step (1), the silica-alumina ratio of the silica-alumina zeolite is 15, and the particle size is 10 mesh.

[0073] The preparation method of the molecular sieve adsorbent desulfurizer in this example is the same as that in Example 1.

[0074] Example 4

[0075] A molecular sieve adsorbent desulfurizer for acidic gases, which comprises the following raw materials: 10 wt% of porous zeolite, 18 wt% of magnesium-aluminum hydrotalcite, 48 wt% of calcium hydroxide, and 24 wt% of magnesium hydroxide.

[0076] The synthesis steps of the porous zeolite are as follows:

[0077] (1) Mix silica-alumina zeolite and dodecyltrimethylammonium hydroxide evenly at a mass ratio of 1:10 to obtain a mixture;

[0078] (2) Stir the mixture obtained in step (1) in a constant temperature water bath at 80 °C for 2 hours and then centrifuge and filter;

[0079] (3) Wash the filter cake to neutral, dry it and put it into a muffle furnace, and calcine it at 550 °C for 6 hours to obtain the porous zeolite.

[0080] Among them, in step (1), the silica-alumina ratio of the silica-alumina zeolite is 5, and the particle size is 70 mesh.

[0081] The preparation method of the molecular sieve adsorbent desulfurizer in this example is the same as that in Example 1.

[0082] Example 5

[0083] A molecular sieve adsorbent desulfurizer for acidic gases, comprising the following raw materials: 8 wt% of porous zeolite, 22 wt% of magnesium-aluminum hydrotalcite, 35 wt% of calcium hydroxide, 25 wt% of magnesium hydroxide, and 10 wt% of sodium hydroxide.

[0084] The synthesis steps of the porous zeolite are as follows:

[0085] (1) Mix silica-alumina zeolite and dodecyltrimethylammonium hydroxide evenly at a mass ratio of 1:8 to obtain a mixture;

[0086] (2) Stir the mixture obtained in step (1) in a constant temperature water bath at 80 °C for 2 hours and then centrifuge and filter;

[0087] (3) Wash the filter cake to neutral, dry it and put it into a muffle furnace, and calcine it at 550 °C for 6 hours to obtain the porous zeolite.

[0088] The preparation method of the molecular sieve adsorbent desulfurizer in this example is the same as that in Example 1.

[0089] Example 6

[0090] A molecular sieve adsorbent desulfurizer for acidic gases, comprising the following raw materials: 8 wt% of porous zeolite, 22 wt% of magnesium-aluminum hydrotalcite, 40 wt% of calcium hydroxide, 20 wt% of magnesium hydroxide, 5 wt% of sodium hydroxide, and 5 wt% of potassium hydroxide.

[0091] The synthesis steps of the porous zeolite are as follows:

[0092] (1) Mix silica-alumina zeolite and dodecyltrimethylammonium hydroxide evenly at a mass ratio of 1:6 to obtain a mixture;

[0093] (2) Stir the mixture obtained in step (1) in a constant temperature water bath at 80 °C for 2 hours and then centrifuge and filter;

[0094] (3) Wash the filter cake to neutral, dry it and put it into a muffle furnace, and calcine it at 550 °C for 6 hours to obtain the porous zeolite.

[0095] Among them, in step (1), the silica-alumina ratio of the silica-alumina zeolite is 15, and the particle size is 60 mesh.

[0096] The preparation method of the molecular sieve adsorbent desulfurizer in this example includes the following steps:

[0097] S1. Grind and mix the porous zeolite, magnesium-aluminum hydrotalcite, calcium hydroxide, magnesium hydroxide, sodium hydroxide, and potassium hydroxide evenly according to the ratio to obtain mixed particles;

[0098] S2. Dry the mixed particles obtained in step S1 at 110 °C;

[0099] S3. Put the dried particles obtained in step S2 into a muffle furnace and calcine them at 350 °C for 10 hours to obtain the adsorptive desulfurizer.

[0100] Example 7

[0101] A molecular sieve adsorptive desulfurizer for acidic gases, which comprises the following raw materials: 8 wt% of porous zeolite, 22 wt% of magnesium-aluminum hydrotalcite, 60 wt% of calcium hydroxide, 5 wt% of sodium hydroxide, and 5 wt% of potassium hydroxide.

[0102] The synthesis steps of the porous zeolite are as follows:

[0103] (1) Mix silica-alumina zeolite and tetradecyltrimethylammonium hydroxide evenly at a mass ratio of 1:6 to obtain a mixture.

[0104] (2) Stir the mixture obtained in step (1) in a constant temperature water bath at 80 °C for 2 hours and then centrifuge and filter.

[0105] (3) Wash the filter cake to neutrality, dry it and put it into a muffle furnace, and calcine it at 550 °C for 6 hours to obtain the porous zeolite.

[0106] Among them, in step (1), the silica-alumina ratio of the silica-alumina zeolite is 15 and the particle size is 60 mesh.

[0107] The preparation method of the molecular sieve adsorptive desulfurizer in this embodiment comprises the following steps:

[0108] S1. Grind and mix porous zeolite, magnesium-aluminum hydrotalcite, calcium hydroxide, sodium hydroxide, and potassium hydroxide evenly according to the ratio to obtain mixed particles.

[0109] S2. Dry the mixed particles obtained in step S1 at 100 °C.

[0110] S3. Put the dried particles obtained in step S2 into a muffle furnace and calcine them at 550 °C for 6 hours to obtain the adsorptive desulfurizer.

[0111] Example 8

[0112] A molecular sieve adsorptive desulfurizer for acidic gases, which comprises the following raw materials: 10 wt% of porous zeolite, 20 wt% of magnesium-aluminum hydrotalcite, and 70 wt% of calcium hydroxide.

[0113] The synthesis steps of the porous zeolite are as follows:

[0114] (1) Mix silica-alumina zeolite and tetradecyltrimethylammonium hydroxide evenly at a mass ratio of 1:8 to obtain a mixture.

[0115] (2) Centrifuge and filter the mixture obtained in step (1) after stirring it in a constant temperature water bath at 80 °C for 2 hours;

[0116] (3) Wash the filter cake to neutrality, dry it and put it into a muffle furnace, and calcine it at 550 °C for 6 hours to obtain the porous zeolite.

[0117] Among them, in step (1), the silica-alumina ratio of the silica-alumina zeolite is 15, and the particle size is 60 mesh.

[0118] The preparation method of the molecular sieve adsorbent desulfurizer in this example includes the following steps:

[0119] S1. Grind and mix the porous zeolite, magnesium-aluminum hydrotalcite, and calcium hydroxide in proportion to obtain mixed particles;

[0120] S2. Dry the mixed particles obtained in step S1 at 120 °C;

[0121] S3. Put the dried particles obtained in step S2 into a muffle furnace and calcine them at 350 °C for 10 hours to obtain the adsorbent desulfurizer.

[0122] Example 9

[0123] A molecular sieve adsorbent desulfurizer for acidic gases, which comprises the following raw materials: 10 wt% of porous zeolite, 20.8 wt% of magnesium-aluminum hydrotalcite, 46 wt% of calcium hydroxide, 23 wt% of magnesium hydroxide, and 0.2 wt% of titanium dioxide with a rutile phase {110} plane.

[0124] Among them, the synthesis steps of the porous zeolite are as follows:

[0125] (1) Mix the silica-alumina zeolite and tetradecyltrimethylammonium hydroxide evenly at a mass ratio of 1:8 to obtain a mixture;

[0126] (2) Centrifuge and filter the mixture obtained in step (1) after stirring it in a constant temperature water bath at 80 °C for 2 hours;

[0127] (3) Wash the filter cake to neutrality, dry it and put it into a muffle furnace, and calcine it at 550 °C for 6 hours to obtain the porous zeolite.

[0128] Among them, in step (1), the silica-alumina ratio of the silica-alumina zeolite is 15, and the particle size is 60 mesh.

[0129] The preparation method of the molecular sieve adsorbent desulfurizer in this example includes the following steps:

[0130] S1. Grind and mix the porous zeolite, magnesium-aluminum hydrotalcite, calcium hydroxide, magnesium hydroxide, and titanium dioxide with a rutile phase {110} plane in proportion to obtain mixed particles;

[0131] S2. Dry the mixed particles obtained in step S1 at 120 °C.

[0132] S3. Put the dried particles obtained in step S2 into a muffle furnace and calcine them at 450 °C for 8 hours to obtain the adsorbent for desulfurization.

[0133] Example 10

[0134] A molecular sieve adsorbent for acidic gases, which comprises the following raw materials: 8 wt% of porous zeolite, 19.6 wt% of magnesium-aluminum hydrotalcite, 48 wt% of calcium hydroxide, 24 wt% of magnesium hydroxide, and 0.4 wt% of rutile-phase titanium dioxide with {110} plane.

[0135] The synthesis steps of the porous zeolite are as follows:

[0136] (1) Mix the silica-alumina zeolite and dodecyltrimethylammonium hydroxide evenly at a mass ratio of 1:8 to obtain a mixture.

[0137] (2) Stir the mixture obtained in step (1) in a constant temperature water bath at 80 °C for 2 hours and then centrifuge and filter.

[0138] (3) Wash the filter cake to neutral, dry it and put it into a muffle furnace, and calcine it at 550 °C for 6 hours to obtain the porous zeolite.

[0139] Among them, in step (1), the silica-alumina ratio of the silica-alumina zeolite is 15, and the particle size is 60 mesh.

[0140] The preparation method of the molecular sieve adsorbent for desulfurization includes the following steps:

[0141] S1. Grind and mix evenly the porous zeolite, hydrotalcite, calcium hydroxide, magnesium hydroxide, and rutile-phase titanium dioxide with {110} plane in proportion to obtain mixed particles.

[0142] S2. Dry the mixed particles obtained in step S1 at 120 °C.

[0143] S3. Put the dried particles obtained in step S2 into a muffle furnace and calcine them at 450 °C for 8 hours to obtain the adsorbent for desulfurization.

[0144] Example 11

[0145] A molecular sieve adsorbent for acidic gases, which includes the same raw materials and preparation method as in Example 10. The difference is that the rutile-phase titanium dioxide with {110} plane is replaced by anatase-type titanium dioxide.

[0146] Example 12

[0147] A molecular sieve adsorbent desulfurizer for acidic gases, comprising the same raw materials and preparation method as in Example 1. The difference lies in that the mass ratio of silica-alumina zeolite to dodecyltrimethylammonium hydroxide in the synthesis step of the porous zeolite is 1:20.

[0148] Example 13

[0149] A molecular sieve adsorbent desulfurizer for acidic gases, comprising the following raw materials: 12 wt% of porous zeolite, 22 wt% of magnesium-aluminum hydrotalcite, 44 wt% of calcium hydroxide, and 22 wt% of magnesium hydroxide.

[0150] The synthesis steps of the porous zeolite are as follows:

[0151] (1) Mix silica-alumina zeolite and dodecyltrimethylammonium hydroxide evenly at a mass ratio of 1:8 to obtain a mixture;

[0152] (2) Stir the mixture obtained in step (1) in a constant temperature water bath at 80 °C for 2 hours and then centrifuge and filter;

[0153] (3) Wash the filter cake to neutral, dry it and put it into a muffle furnace, and calcine it at 550 °C for 6 hours to obtain the porous zeolite.

[0154] Among them, in step (1), the silica-alumina ratio of the silica-alumina zeolite is 50, and the particle size is 60 mesh.

[0155] The preparation method of the molecular sieve adsorbent desulfurizer in this example is the same as that in Example 1.

[0156] Example 14

[0157] A molecular sieve adsorbent desulfurizer for acidic gases, comprising the following raw materials: 10 wt% of porous zeolite, 18 wt% of magnesium-aluminum hydrotalcite, 48 wt% of calcium hydroxide, and 24 wt% of magnesium hydroxide.

[0158] The synthesis steps of the porous zeolite are as follows:

[0159] (1) Mix silica-alumina zeolite and sodium hydroxide evenly at a mass ratio of 1:8 to obtain a mixture;

[0160] (2) Stir the mixture obtained in step (1) in a constant temperature water bath at 80 °C for 2 hours and then centrifuge and filter;

[0161] (3) Wash the filter cake to neutral and dry it;

[0162] (4) Mix the dried sample in step (3) and ammonium nitrate evenly at a mass ratio of 1:8, stir again in a constant temperature water bath at 80 °C for 1 hour and then centrifuge and filter;

[0163] (5) Wash the filter cake to remove the excess ammonium nitrate. After drying, put it into a muffle furnace and calcine it at 550 °C for 6 hours to obtain the porous zeolite.

[0164] Among them, in step (1), the silica-alumina ratio of the silica-alumina zeolite is 15 and the particle size is 60 mesh.

[0165] The preparation method of the molecular sieve adsorbent desulfurizer in this example is the same as that in Example 1.

[0166] Example 15

[0167] A molecular sieve adsorbent desulfurizer for acidic gases, which includes the same raw materials and preparation method as in Example 1. The difference is that in the synthesis step of the porous zeolite, dodecyltrimethylammonium hydroxide is replaced by tetrapropylammonium hydroxide.

[0168] Comparative Example 1

[0169] A molecular sieve adsorbent desulfurizer for acidic gases, which includes the following raw materials: 8 wt% of ordinary silica-alumina zeolite, 20 wt% of magnesium-aluminum hydrotalcite, 48 wt% of calcium hydroxide, and 24 wt% of magnesium hydroxide. Among them, the silica-alumina ratio of the ordinary silica-alumina zeolite is 15 and the particle size is 60 mesh.

[0170] The preparation method of the molecular sieve adsorbent desulfurizer includes the following steps:

[0171] (1) Grind and mix the porous zeolite, magnesium-aluminum hydrotalcite, calcium hydroxide, and magnesium hydroxide in proportion to obtain mixed particles;

[0172] (2) Dry the mixed particles obtained in step S1 at 120 °C;

[0173] (3) Put the dried particles obtained in step S2 into a muffle furnace and calcine them at 450 °C for 8 hours to obtain the adsorbent desulfurizer.

[0174] Evaluation of the desulfurization effect by adsorption:

[0175] Spray the desulfurizers prepared in the above Examples 1-15 and Comparative Example 1 into the flue gas pipeline respectively. Spray 0.2 kg of desulfurizer per cubic meter of flue gas, introduce the flue gas for mixed desulfurization, and use a flue gas analyzer to measure the sulfur content before and after the desulfurization pipeline. The desulfurization efficiency of the treated flue gas is shown in Table 1.

[0176] Calculation method of desulfurization efficiency: Desulfurization efficiency = (Initial flue gas sulfur content - Desulfurized flue gas sulfur content) / Initial flue gas sulfur content × 100%

[0177] Table 1 Adsorption desulfurization efficiency

[0178] Number Desulfurization Efficiency (%) Example 1 96.9 Example 2 96.3 Example 3 95.9 Example 4 95.6 Example 5 93.8 Example 6 95.0 Example 7 93.7 Example 8 92.8 Example 9 97.9 Example 10 98.3 Example 11 97.0 Example 12 90.3 Example 13 85.7 Example 14 89.6 Example 15 90.7 Comparative Example 1 83.1

[0179] As can be seen from the results in Table 1, Examples 1-11 of the present invention all have good adsorption desulfurization efficiency. Comparative Example 1 uses unmodified ordinary silica-alumina zeolite, which has a single pore size of silica-alumina zeolite and poor adsorption desulfurization efficiency; the difference between Example 11 and Example 10 is the selection of anatase titanium dioxide. It can be seen that the adsorption effect of the rutile {110} plane is slightly better than that of the anatase phase in some embodiments of the present application; in Example 12, during the synthesis step of the porous zeolite, the mass ratio of silica-alumina zeolite to dodecyltrimethylammonium hydroxide is adjusted to 1:20, which affects the modification effect and reaction activity of the porous zeolite, and thus affects the adsorption desulfurization efficiency; Example 13 selects silica-alumina zeolite with a silica-alumina ratio of 50. Too high a silica-alumina ratio will affect the electrostatic field inside the zeolite crystal, and thus affect the adsorption desulfurization efficiency; in Examples 14-15, during the synthesis step of the porous zeolite, sodium hydroxide and tetrapropylammonium hydroxide are respectively selected. It can be seen that selecting a suitable strong organic base for the modification of silica-alumina zeolite can not only reduce the additional ion exchange step, but also improve the adsorption desulfurization efficiency.

[0180] The above are only the preferred embodiments of the present invention, and do not impose any form of limitation on the present application. Although the present application is disclosed above with preferred embodiments, it is not intended to limit the present application. Any person skilled in the art, without departing from the scope of the technical solution of the present application, makes some changes or modifications using the technical content disclosed above, which are equivalent to equivalent embodiments. However, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still fall within the scope of the technical solution.

Claims

1. A molecular sieve adsorbent desulfurizer for acidic gases, characterized in that, It includes the following raw materials: 8 - 12 wt% of porous zeolite, 18 - 22 wt% of hydrotalcite, and 65 - 75 wt% of hydroxide.

2. The molecular sieve adsorption desulfurizer according to claim 1, wherein The synthesis steps of the porous zeolite are as follows: (1) Mix the silica-alumina zeolite and the alkaline compound evenly to obtain a mixture; (2) Stir the mixture obtained in step (1) in a constant temperature water bath at 60 - 90 °C for 1 - 3 hours and then centrifuge and filter; (3) Wash the filter cake to neutral, dry it and put it into a muffle furnace, and calcine it at 500 - 600 °C for 4 - 8 hours to obtain the porous zeolite.

3. The molecular sieve adsorption desulfurizer according to claim 2, characterized in that, The particle size range of the silica-alumina zeolite is 10 - 70 mesh.

4. The molecular sieve adsorption desulfurizer according to claim 2, characterized in that The mass ratio of the silica-alumina zeolite to the alkaline compound is 1:(6 - 10).

5. The molecular sieve adsorption desulfurizer according to claim 2, characterized in that, The alkaline compound used for synthesizing the porous zeolite is a strong organic base.

6. The molecular sieve adsorption desulfurizer according to claim 5, characterized in that, The strong organic base is dodecyltrimethylammonium hydroxide or tetradecyltrimethylammonium hydroxide.

7. The molecular sieve adsorption desulfurizer according to claim 1, characterized in that, The hydroxide is one or more of magnesium hydroxide, calcium hydroxide, potassium hydroxide and sodium hydroxide.

8. The molecular sieve adsorption desulfurizer according to claim 1, wherein The hydrotalcite is a divalent cation Ni 2+ / Mg 2+ and a trivalent cation Al 3+ / Ti 3+ binary compound formed.

9. The molecular sieve adsorption desulfurizer according to claim 1, characterized in that, The raw materials of the adsorptive desulfurizer also contain 0.2 - 0.4 wt% of titanium dioxide.

10. A method for preparing a molecular sieve adsorbent for desulfurization according to any one of claims 1-8, characterized in that, It includes the following steps: S1. Grind and mix the porous zeolite, hydrotalcite and hydroxide proportionally to obtain mixed particles; S2. Dry the mixture particles obtained in step S1 at 100 - 120 °C; S3. Put the dried particles obtained in step S2 into a muffle furnace and calcine them at 350 - 550 °C for 6 - 10 hours to obtain the molecular sieve adsorptive desulfurizer.