Composite granular desulfurizer and preparation method thereof

Abstract

The invention provides a composite granular desulfurizer and a preparation method thereof. The desulfurizer comprises the following components: zinc oxide, calcium oxide, iron oxide, coke, activated carbon, modified attapulgite, a pore-enlarging agent and aluminum oxide. The preparation method comprises the following steps: uniformly mixing the components, feeding into a calcining furnace, roasting at 350-450 DEG C for 2-4 hours to obtain a calcined material, crushing, extruding and forming, and screening by using a vibrating screen to obtain the desulfurizing agent. The desulfurizer is prepared by loading calcium oxide with aluminum oxide, and ferric oxide is added to further catalyze the desulfurization reaction, so that the desulfurization reaction process is changed, and the desulfurization efficiency is improved. The pore-enlarging agent is used for pore-forming of desulfurizer particles, the adsorption performance of the active substance calcium oxide in the desulfurizer is improved, meanwhile, the mechanical performance of the desulfurizer particles is changed, the desulfurizer particles can be repeatedly used, and the regeneration performance of the desulfurizer is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of waste gas treatment, and particularly relates to a composite granular desulfurizing agent and a preparation method thereof. Background Art

[0002] SO 2 It is a gas that is extremely harmful to the natural environment and is the main factor causing acid rain. SO 2 Emissions mainly come from the combustion of fossil fuels such as coal, oil and natural gas. 2 The main means of emission is desulfurization before, during and after the combustion of coal, oil and natural gas. At present and even in the next few years, flue gas desulfurization will still be the main SO 2 The most effective means of pollution control. Flue gas desulfurization is mainly based on dry desulfurization process, which is to absorb SO in flue gas by desulfurization agent. 2 Or sulfuric acid to achieve flue gas desulfurization. Among the desulfurizers currently used, the supported desulfurizer has a good SO 2 However, supported desulfurizers also have the following defects: (1) adsorption of SO 2 After saturation, it cannot be regenerated; (2) The pores in the CaO particles are quickly filled with CaSO 4 The blockage limits the desulfurization efficiency and the utilization rate of the desulfurizer. Summary of the invention

[0003] In view of the defects of existing desulfurizers, such as non-reusability and low adsorption rate of loaded materials, the present invention provides a composite granular desulfurizer and a preparation method thereof, which improves the adsorption capacity and regeneration capacity of the active substances in the desulfurizer, so that the prepared desulfurizer has high utilization rate and desulfurization efficiency.

[0004] The present invention is achieved through the following technical solutions: A composite granular desulfurizer comprises the following components in weight proportions: 4-5 parts of zinc oxide, 8-12 parts of calcium oxide, 4-5 parts of iron oxide, 8-15 parts of coke, 10-15 parts of activated carbon, 10-15 parts of modified attapulgite, 1-3 parts of pore expander and 8-10 parts of aluminum oxide.

[0005] Preferably, the modified attapulgite comprises raw materials in parts by weight: 60 parts of attapulgite, 15 parts of acrylic acid, 8 parts of kaolin, 6 parts of a crosslinking agent, 6 parts of zinc stearate, 4 parts of titanium sulfate, 2 parts of lanthanum oxide, and 4 parts of water; the crosslinking agent is N,N-methylenebisacrylamide or ethylene glycol dimethacrylate; The preparation method of the modified attapulgite is as follows: firstly, attapulgite and kaolin are put into a calcining furnace, calcined at 500-600°C for 8 hours, taken out and cooled, acrylic acid and a crosslinking agent are added, water is added and stirred for reaction, the pH value of the material is adjusted to 7-8, the reaction is carried out for 2 hours to obtain a 80-100 mesh slurry, and then other remaining ingredients are added, stirring is continued to obtain a 80-100 mesh slurry, and spray drying is carried out to obtain the modified attapulgite.

[0006] Preferably, the alumina is selected from γ-alumina, α-alumina, δ-alumina, θ-alumina or a mixture thereof.

[0007] Preferably, the pore expanding agent is one of polyethylene, polystyrene, graphite and microcrystalline cellulose, and the particle size is 6-150 μm.

[0008] Preferably, the ratio of calcium oxide to iron oxide is (2-3):1.

[0009] At the same time, the present invention provides a method for preparing the composite granular desulfurizer, comprising the following steps: (1) zinc oxide, calcium oxide, iron oxide, coke, activated carbon, modified attapulgite, pore-enlarging agent and alumina are mixed evenly, put into a calcining furnace, and roasted at 350-450° C. for 2-4 hours to obtain a calcined material; (2) The calcined material obtained in step (1) is crushed to a particle size of 10-100 mesh, then maintained at a low pressure of 4 MPa for 10 minutes, continuously extruded at a high pressure of 10-30 MPa, and sieved with a vibrating screen to obtain a finished desulfurizer. The particle fineness of the desulfurizer is controlled to be 0.1-3 mm.

[0010] The present invention uses calcium oxide as an active substance loaded on aluminum oxide, and adds iron oxide as a catalyst to prepare a desulfurizer, and adds a pore-enlarging agent to improve the adsorption performance of calcium oxide. Iron oxide can change the calcium-aluminum desulfurizer to remove SO 2 The reaction process of desulfurization changes from adsorption first and oxidation later to oxidation first and adsorption later. At the same time, Fe ions promote the reaction of CaO and SO 2 The reaction produces CaSO 4 , greatly improving the desulfurization agent to SO 2The removal capacity of calcium oxide can be improved. The pore expander can not only improve the adsorption capacity of calcium oxide, but also strengthen the mechanical properties of the desulfurizer particles, because the pore expander generates gas during pyrolysis, which will generate channels inside the particles, making it easier for calcium hydroxide or calcium carbonate to decompose a large amount of water vapor and carbon dioxide gas at high temperature to diffuse, thus avoiding these gases from causing additional cracks in the particles, thereby improving the mechanical properties of the particles and further improving the regeneration performance of the desulfurizer. The modified attapulgite can be evenly mixed with zinc oxide, calcium oxide, iron oxide, etc., which plays a certain bonding role and is conducive to the formation of material particles. In addition, the added attapulgite itself has good adsorption capacity, and combined with zinc oxide and calcium oxide, the synergistic effect can improve the adsorption capacity of the desulfurizer and improve the desulfurization efficiency.

[0011] The beneficial effects of the present invention are as follows: The present invention prepares a desulfurizer by loading calcium oxide on alumina, and adds iron oxide to further catalyze the desulfurization reaction, thereby changing the desulfurization reaction process and improving the desulfurization efficiency. By using a pore-enlarging agent to form pores on the desulfurizer particles, the adsorption performance of the active substance calcium oxide in the desulfurizer is improved, and the mechanical properties of the desulfurizer particles are changed, so that the desulfurizer particles can be repeatedly used, and the regeneration performance of the desulfurizer is improved. DETAILED DESCRIPTION

[0012] The present invention will be further described below in conjunction with the embodiments.

[0013] Example 1: A composite granular desulfurizer comprises the following components in weight proportions: 4 parts of zinc oxide, 8 parts of calcium oxide, 4 parts of iron oxide, 8 parts of coke, 10 parts of activated carbon, 10 parts of modified attapulgite, 1 part of pore expander, 8 parts of γ-alumina and 5 parts of catalyst.

[0014] The modified attapulgite comprises the following raw materials in parts by weight: 60 parts of attapulgite, 15 parts of acrylic acid, 8 parts of kaolin, 6 parts of N,N-methylenebisacrylamide, 6 parts of zinc stearate, 4 parts of titanium sulfate, 2 parts of lanthanum oxide, and 4 parts of water.

[0015] The preparation method of the modified attapulgite is as follows: firstly, attapulgite and kaolin are put into a calcining furnace, calcined at 500°C for 8 hours, taken out and cooled, acrylic acid and a crosslinking agent are added, water is added and stirred for reaction, the pH value of the material is adjusted to 7, the reaction is carried out for 2 hours to obtain 80 mesh slurry, and then other remaining components are added, the reaction is continued to obtain 80 mesh slurry, and the modified attapulgite is prepared by spray drying.

[0016] The pore expanding agent is polyethylene, and the particle size is 6 μm.

[0017] The preparation method of the composite granular desulfurizer comprises the following steps: (1) zinc oxide, calcium oxide, iron oxide, coke, activated carbon, modified attapulgite, pore-enlarging agent and alumina are mixed uniformly, put into a calcining furnace, and calcined at 350° C. for 4 hours to obtain a calcined material; (2) The calcined material obtained in step (1) is crushed to a particle size of 10 mesh, then maintained at a low pressure of 4 MPa for 10 minutes, continuously extruded at a high pressure of 10 MPa, and sieved with a vibrating screen to obtain a finished desulfurizer. The particle fineness of the desulfurizer is controlled at 3 mm.

[0018] Example 2: A composite granular desulfurizer comprises the following components in weight ratio: 5 parts of zinc oxide, 12 parts of calcium oxide, 5 parts of iron oxide, 15 parts of coke, 15 parts of activated carbon, 15 parts of modified attapulgite, 3 parts of pore expander, and 10 parts of aluminum oxide.

[0019] The alumina is a mixture of α-alumina and δ-alumina.

[0020] The modified attapulgite comprises the following raw materials in parts by weight: 60 parts of attapulgite, 15 parts of acrylic acid, 8 parts of kaolin, 6 parts of ethylene glycol dimethacrylate, 6 parts of zinc stearate, 4 parts of titanium sulfate, 2 parts of lanthanum oxide, and 4 parts of water; The preparation method of the modified attapulgite is as follows: firstly, attapulgite and kaolin are put into a calcining furnace, calcined at 600°C for 8 hours, taken out and cooled, acrylic acid and a crosslinking agent are added, water is added and stirred for reaction, the pH value of the material is adjusted to 8, the reaction is carried out for 2 hours to obtain a 100-mesh slurry, and then other remaining ingredients are added, stirring is continued to obtain a 100-mesh slurry, and spray drying is carried out to obtain the modified attapulgite.

[0021] The pore-enlarging agent is microcrystalline cellulose with a particle size of 20 μm.

[0022] The preparation method of the composite granular desulfurizer comprises the following steps: (1) zinc oxide, calcium oxide, iron oxide, coke, activated carbon, modified attapulgite, pore-enlarging agent and alumina are mixed uniformly, put into a calcining furnace, and calcined at 450° C. for 2 hours to obtain a calcined material; (2) The calcined material obtained in step (1) is crushed to a particle size of 100 mesh, then maintained at a low pressure of 4 MPa for 10 minutes, continuously extruded at a high pressure of 30 MPa, and sieved with a vibrating screen to obtain a finished desulfurizer. The particle fineness of the desulfurizer is controlled at 0.1 mm.

[0023] Example 3: A composite granular desulfurizer comprises the following components in weight ratio: 4.8 parts of zinc oxide, 9 parts of calcium oxide, 4.5 parts of iron oxide, 12 parts of coke, 12 parts of activated carbon, 12 parts of modified attapulgite, 2 parts of pore expander, and 9 parts of aluminum oxide.

[0024] The aluminum oxide is θ-aluminum oxide.

[0025] The modified attapulgite comprises the following raw materials in parts by weight: 60 parts of attapulgite, 15 parts of acrylic acid, 8 parts of kaolin, 6 parts of N,N-methylenebisacrylamide, 6 parts of zinc stearate, 4 parts of titanium sulfate, 2 parts of lanthanum oxide, and 4 parts of water; The preparation method of the modified attapulgite is as follows: firstly, attapulgite and kaolin are put into a calcining furnace, calcined at 550°C for 8 hours, taken out and cooled, acrylic acid and a crosslinking agent are added, water is added and stirred for reaction, the pH value of the material is adjusted to 7.8, the reaction is carried out for 2 hours to obtain a 90-mesh slurry, and then other remaining ingredients are added, stirring is continued to obtain a 90-mesh slurry, and spray drying is carried out to obtain the modified attapulgite.

[0026] The pore expanding agent is graphite with a particle size of 150 μm.

[0027] The preparation method of the composite granular desulfurizer comprises the following steps: (1) zinc oxide, calcium oxide, iron oxide, coke, activated carbon, modified attapulgite, pore-enlarging agent and alumina are mixed uniformly, put into a calcining furnace, and calcined at 400° C. for 3 hours to obtain a calcined material; (2) The calcined material obtained in step (1) is crushed to a particle size of 50 mesh, then maintained at a low pressure of 4 MPa for 10 minutes, continuously extruded at a high pressure of 2 MPa, and sieved with a vibrating screen to obtain a finished desulfurizer. The particle fineness of the desulfurizer is controlled to be 1 mm.

[0028] Application example: The desulfurizer prepared in Example 3 is used for desulfurization of flue gas of a coal-fired boiler, and the composition of the flue gas of the coal-fired boiler is shown in Table 1. Specifically, the desulfurizer is placed in a quartz reaction tube, and then placed in a flue tube to allow the coal-fired gas to pass through the quartz reaction tube. The data before and after desulfurization are shown in Table 2.

[0029] Table 1:

[0030] Table 2:

[0031] From the data in Table 2, it can be seen that the desulfurizer prepared in Example 3 has an effective effect on SO 2 Removed 71% and absorbed 62.3% of CO 2 .

[0032] The desulfurized desulfurizer is passed into N 2The gas was purged for 20 minutes, and then methane gas was introduced at a flow rate of 100 mL / min to regenerate the desulfurizer after desulfurization at 550°C. The number of regenerations and the corresponding sulfur capacity and regeneration rate are shown in Table 3.

[0033] Table 3:

[0034] It can be seen from Table 3 that the desulfurizer prepared in Example 3 has a good regeneration effect and can be used for flue gas desulfurization multiple times.

[0035] The above embodiments are only exemplary embodiments of the present invention and are not intended to limit the present invention. The protection scope of the present invention is defined by the claims. Those skilled in the art may make various modifications or equivalent substitutions to the present invention within the essence and protection scope of the present invention, and such modifications or equivalent substitutions shall also be deemed to fall within the protection scope of the present invention.

Claims

1. A composite granular desulfurizer, characterized in that: The invention comprises the following components in weight proportions: 4-5 parts of zinc oxide, 8-12 parts of calcium oxide, 4-5 parts of iron oxide, 8-15 parts of coke, 10-15 parts of activated carbon, 10-15 parts of modified attapulgite, 1-3 parts of pore expander and 8-10 parts of aluminum oxide.

2. The composite granular desulfurizer according to claim 1, characterized in that: The modified attapulgite comprises the following raw materials in parts by weight: 60 parts of attapulgite, 15 parts of acrylic acid, 8 parts of kaolin, 6 parts of a crosslinking agent, 6 parts of zinc stearate, 4 parts of titanium sulfate, 2 parts of lanthanum oxide, and 4 parts of water; the crosslinking agent is N,N-methylenebisacrylamide or ethylene glycol dimethacrylate; The preparation method of the modified attapulgite is as follows: firstly, attapulgite and kaolin are put into a calcining furnace, calcined at 500-600°C for 8 hours, taken out and cooled, acrylic acid and a crosslinking agent are added, water is added and stirred for reaction, the pH value of the material is adjusted to 7-8, the reaction is carried out for 2 hours to obtain a 80-100 mesh slurry, and then other remaining ingredients are added, stirring is continued to obtain a 80-100 mesh slurry, and spray drying is carried out to obtain the modified attapulgite.

3. The composite granular desulfurizer according to claim 1, characterized in that: The alumina is selected from γ-alumina, α-alumina, δ-alumina, θ-alumina or a mixture thereof.

4. The composite granular desulfurizer according to claim 1, characterized in that: The pore-enlarging agent is one of polyethylene, polystyrene, graphite and microcrystalline cellulose, and the particle size is 6-150 μm.

5. The composite granular desulfurizer according to claim 1, characterized in that: The dosage ratio of calcium oxide to iron oxide is (2-3):

1.

6. The method for preparing the composite granular desulfurizer according to any one of claims 1 to 5, characterized in that: The following steps are involved: (1) zinc oxide, calcium oxide, iron oxide, coke, activated carbon, modified attapulgite, pore-enlarging agent and alumina are mixed evenly, put into a calcining furnace, and roasted at 350-450° C. for 2-4 hours to obtain a calcined material; (2) The calcined material obtained in step (1) is crushed to a particle size of 10-100 mesh, then maintained at a low pressure of 4 MPa for 10 minutes, continuously extruded at a high pressure of 10-30 MPa, and sieved with a vibrating screen to obtain a finished desulfurizer. The particle fineness of the desulfurizer is controlled to be 0.1-3 mm.

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