Denitrification combustion-supporting and acid mist removing additive

Abstract

The present invention discloses a denitrification combustion-supporting and acid mist removing additive, belonging to the technical field of sulfur transfer agents for catalytic cracking flue gas. This method involves reacting precisely proportioned ferric chloride, magnesium chloride, aluminum chloride with an aqueous sodium hydroxide solution to form a cross-linking agent solution, mixing it with modified magnesium saponite and conducting a heating and heat preservation treatment to form a cross-linked structure. Subsequently, the cross-linked magnesium saponite is impregnated in a solution containing various metal salts and calcined to obtain the final additive. The preparation of the modified magnesium saponite uses polyethylene glycol ether and sodium aluminosilicate to optimize the pore structure and thermal stability. Compared with the prior art, the additive of the present invention effectively reduces the emissions of SO X and NO X during the catalytic cracking process, especially the emission of sulfur trioxide, improves the combustion efficiency, reduces the generation of pollutants, and at the same time avoids the use of toxic substances, reduces environmental pollution, and has significant environmental and economic benefits.

Description

Technical Field

[0001] The present invention relates to the technical field of sulfur transfer agents for catalytic cracking flue gas, and particularly to an auxiliary agent for denitrification, combustion promotion and acid mist removal. Background Art

[0002] The emissions of acidic substances such as sulfides and nitrides are increasing continuously. In particular, the emissions of sulfides have caused serious impacts on the environment, leading to the expansion of the acid rain area year by year. To address this challenge, investment in environmental protection monitoring and law enforcement capacity building has been increased, and effective emission reduction technologies are urgently needed.

[0003] In the refining industry, catalytic cracking units are the main sources of sulfur oxide emissions. Facing the current situation of heavy crude oil and increasing proportion of high-sulfur crude oil, traditional sulfur oxide emission reduction technologies such as hydrodesulfurization and washing desulfurization methods face problems such as large investment, high operating costs, and secondary pollution. Therefore, it has become an urgent task to develop an economic, efficient, and environmentally friendly sulfur oxide emission reduction technology.

[0004] Currently, there are mainly three measures to control sulfur oxide emissions from catalytic cracking unit flue gas: hydrodesulfurization pretreatment method, washing desulfurization method, and adding sulfur transfer agent method. Although the hydrodesulfurization method can improve product properties and reduce sulfur content, it has problems such as high investment and operating costs, and complex equipment. Although the washing desulfurization method has a high desulfurization efficiency, it also has disadvantages such as large investment, wide floor area, and generation of waste water. In contrast, the method of adding sulfur transfer agent has become the most economical solution with its advantages of low cost, no need for new equipment, and simple operation.

[0005] The principle of action of the sulfur transfer agent is to realize the absorption-release process of SO X in the reaction-regeneration system of the catalytic cracking unit. In the regenerator, the sulfur transfer agent reacts with SO X to form metal sulfate, and then is reduced and released H 2 S in the reactor, completing the transfer of sulfur, and then being recovered in the form of sulfur through the downstream sulfur recovery device to realize the resource utilization of sulfur.

[0006] Chinese invention patent CN102755809B discloses a preparation method of a pillar-supported saponite-type catalytic cracking flue gas sulfur transfer agent. The method comprises the following steps: mixing saponite with water to obtain a saponite dispersion; mixing an iron source, a magnesium source, an aluminum source and / or a cerium source with water or oxalic acid, adding an NaOH solution to prepare a crosslinking agent solution; mixing the saponite dispersion and the crosslinking agent solution, maintaining at 10-80 °C for 5-30 h, and then maintaining at 90-130 °C for 1-40 h to obtain crosslinked saponite; impregnating cerium nitrate on the crosslinked saponite and calcining to obtain the pillar-supported saponite-type catalytic cracking flue gas sulfur transfer agent. The pillar-supported saponite-type catalytic cracking flue gas sulfur transfer agent prepared by the method provided by the invention has good desulfurization activity. However, the sulfur transfer agent of the invention has problems of insufficient desulfurization efficiency and stability, which limits its wide application and adaptability under different operating conditions. Summary of the Invention

[0007] Aiming at the defects of the prior art, the present invention provides a preparation method of a denitration combustion-supporting acid mist removal additive. By finely controlling the raw material mixing, crosslinking reaction and calcination process, the method realizes high desulfurization activity, and at the same time may reduce the harsh requirements on equipment and operating conditions, improves the feasibility of the preparation process and the economy of the desulfurizer, and helps to solve the problems of high cost, complex operation or insufficient desulfurization efficiency existing in the prior art.

[0008] In the field of industrial emission control, "acid mist removal" refers to compounds or mixtures that can neutralize or transform acidic substances. These substances are used in industrial processes, especially in petroleum refining and chemical production, to reduce the emission of acidic gases such as SO X and NO X . In the catalytic cracking process, the acid mist removal additive captures and transforms acidic oxides such as SO 3 through chemical action, thereby reducing its corrosive impact on the environment and equipment.

[0009] "Acid mist" generally refers to substances with acidic properties that can release hydrogen ions (H+) or react with water to form an acidic solution. In the catalytic cracking flue gas, SO 3 is a typical acid mist because it easily reacts with water to form sulfuric acid, increasing the acidity of the flue gas. The emission of SO 3 not only causes the formation of acid rain, but also poses a serious threat to human health and the ecosystem.

[0010] The acid mist removal additive is a chemical additive specifically designed to reduce the emission of acidic substances in industrial processes. In the catalytic cracking process, oxides of sulfur and nitrogen (such as SO X and NO X) are the main pollutants. They not only cause serious pollution to the environment but may also corrode equipment. In particular, sulfur trioxide (SO 3 ), which is a strong acidic substance, can react with water to form sulfuric acid, further exacerbating the harm to the environment and equipment.

[0011] The denitration combustion-supporting and acid mist removing additive of the present invention effectively captures and converts these acidic substances through a series of actions. In the regenerator, the additive reacts with SO X to form metal sulfate, and then is reduced in the reactor to release H 2 S, completing the transfer of sulfur. This process not only reduces the emission of SO 3 but also realizes the resource utilization of sulfur, converting the original pollutant into sulfur that can be recycled.

[0012] In addition, this additive also has a combustion-supporting effect, which can improve the combustion efficiency, reduce the emission of carbon monoxide (CO), and further enhance the environmental protection performance of the industrial process. By using this additive, high-efficiency desulfurization and combustion-supporting effects can be achieved with low investment and operating costs without adding new equipment, having significant economic and environmental benefits.

[0013] In order to achieve the above-mentioned invention purpose, the present invention adopts the following technical solutions:

[0014] A preparation method of a denitration combustion-supporting and acid mist removing additive is as follows:

[0015] Step 1: Mix ferric chloride, magnesium chloride, aluminum chloride with water, and add an aqueous sodium hydroxide solution to prepare a crosslinking agent solution;

[0016] Step 2: Mix the modified magnesium saponite with the crosslinking agent solution prepared in Step 1, heat up and keep warm to obtain crosslinked magnesium saponite;

[0017] Step 3: Immerse the crosslinked magnesium saponite in a metal salt solution to obtain the impregnated magnesium saponite;

[0018] Step 4: Calcine the impregnated magnesium saponite to obtain the denitration combustion-supporting and acid mist removing additive.

[0019] The weight parts of each substance in Step 1 are: 120 - 180 parts of ferric chloride, 80 - 120 parts of magnesium chloride, 80 - 100 parts of aluminum chloride, 1800 - 2200 parts of water, 400 - 600 parts of 0.5 - 2 mol / L aqueous sodium hydroxide solution.

[0020] The mass ratio of the modified magnesium saponite to the crosslinking agent solution prepared in Step 1 is 1:2 - 4.

[0021] The mass ratio of the crosslinked magnesium saponite to the metal salt solution is 1:8 - 12.

[0022] The heating and heat preservation treatment is to maintain at 40-60 °C for 10-30 hours, and then maintain at 80-110 °C for 10-30 hours.

[0023] The metal salt solution contains 0.01-0.03 mol / L silver chloride, 0.005-0.02 mol / L chloroplatinic acid, 0.005-0.02 mol / L palladium chloride, 0.02-0.04 mol / L cobalt chloride, 0.04-0.06 mol / L nickel chloride, 0.03-0.05 mol / L bismuth acetate, 0.05-0.07 mol / L zinc chloride, 0.07-0.09 mol / L titanium tetrachloride, 0.02-0.04 mol / L zirconium chloride, and 0.01-0.03 mol / L sodium tungstate.

[0024] The roasting temperature is 400-800 °C, and the roasting time is 3-8 hours.

[0025] The preparation method of the modified magnesite is as follows, by weight:

[0026] S1. Dissolve sodium hydroxide and sodium bicarbonate in water to prepare an alkali solution; the mass ratio of sodium hydroxide, sodium bicarbonate, and water is 0.5-2:1-2:12-18;

[0027] S2. Dissolve magnesium chloride and aluminum chloride in water to prepare a magnesium-aluminum aqueous solution, and the mass ratio of magnesium chloride, aluminum chloride, and water is 0.5-2:15-25:300-500;

[0028] S3. Dissolve polyethylene glycol ether in water to prepare an aqueous solution containing polyethylene glycol ether, and the mass ratio of polyethylene glycol ether to water is 0.5-2:4-6;

[0029] S4. Under the conditions of constant temperature at 80-90 °C and stirring, first add 80-120 parts of sodium aluminosilicate to 500-700 parts of the alkali solution to obtain a silicon-containing solution, and then drop 150-250 parts of the magnesium-aluminum aqueous solution and 150-250 parts of the aqueous solution containing polyethylene glycol ether into the silicon-containing solution. After dropping, continue to stir for 2-4 hours to obtain a reaction solution;

[0030] S5. Add the reaction solution to a crystallization kettle and seal it. Crystallize at a constant temperature of 150-180 °C for 10-20 hours. After crystallization is completed, cool to room temperature, and then perform centrifugation, water washing, vacuum drying at 30-50 °C for 5-15 hours, crushing, and sieving through a 50-200 mesh sieve to obtain the modified magnesite.

[0031] In the preparation method of the denitrification combustion-supporting and acid mist removing additive of the present invention, each substance has the following functions:

[0032] Ferric chloride, magnesium chloride, and aluminum chloride are used as metal sources. They react with sodium hydroxide to form corresponding hydroxides, which are the basis for preparing the crosslinking agent solution and are used to react with hectorite subsequently to form a crosslinked structure.

[0033] Sodium hydroxide, as a strong base, is used to adjust the pH value of the solution, promote the hydrolysis of metal chlorides to form hydroxides, and simultaneously play a crosslinking role.

[0034] The modified hectorite serves as a carrier for the catalyst, providing a specific pore structure and surface characteristics, which helps to improve the catalytic efficiency and selectivity.

[0035] Polyethylene glycol ether, polypropylene glycol, and polyethylene glycol are used as organic treatment agents to improve the pore structure and surface properties of hectorite, enhance its dispersibility and stability, and contribute to improving the catalytic performance.

[0036] Sodium aluminosilicate, silica sol, and sodium silicate are used as silicon sources to participate in the formation of the framework structure of modified hectorite, affecting the porosity and thermal stability of the material.

[0037] The metal salt solution (including silver chloride, chloroplatinic acid, and palladium chloride) is used as a noble metal source. These metal ions are fixed on hectorite during the impregnation process to form active components, which play a catalytic role in reactions such as denitrification, combustion promotion, and acid removal.

[0038] Cobalt chloride, nickel chloride, bismuth acetate, zinc chloride, titanium tetrachloride, zirconium chloride, and sodium tungstate may act as cocatalysts or promoters to improve the activity and stability of the catalyst.

[0039] Through the combined action of these substances, the denitrification, combustion promotion, and acid mist removal aid of the present invention can effectively reduce the emissions of SO X and NO X during the catalytic cracking process, improve the combustion efficiency, and reduce the generation of pollutants.

[0040] Compared with the prior art, it has the following several beneficial effects:

[0041] 1) The denitrification, combustion promotion, and acid mist removal aid of the present invention shows excellent desulfurization efficiency. Adding 2% of the denitrification, combustion promotion, and acid mist removal aid can significantly reduce the concentration of SO in the flue gas, and after continuous operation for 216 hours, it can still maintain a desulfurization rate of more than 85%, which is higher than the desulfurization rate of about 70% of general products. 2 2) Compared with the hydrodesulfurization and washing desulfurization methods, the denitrification, combustion promotion, and acid mist removal aid of the present invention does not require adding new equipment and has lower investment costs and operating costs. This is particularly economical for devices with a SO

[0042] content not greater than 1500 μg / g in the flue gas, as it provides a cost-effective solution. x content not greater than 1500 μg / g in the flue gas, as it provides a cost-effective solution.

[0043] 3) The denitration combustion-supporting and acid mist removing additive of the present invention has been optimized in terms of composition, avoiding the use of toxic vanadium species and reducing the use of nitrates, thereby reducing the potential toxicity to workers and the environment. At the same time, its use in the fluid catalytic cracking unit has no adverse effects on the heavy oil conversion ability of the main catalyst, the yields and properties of various products, showing good process compatibility. Detailed implementation mode

[0044] Main sources of substances:

[0045] Polyethylene glycol: Guangzhou Tongyang Chemical Co., Ltd., model: OEG6000.

[0046] Polypropylene glycol: Tianjin Zhonghe Shengtai Chemical Co., Ltd., product number: DL-2000D.

[0047] Polyethylene glycol ether: Wuhan Lanabai Pharmaceutical and Chemical Co., Ltd., product number: 19052713.

[0048] Sodium silicate: CAS number: 1344-09-8.

[0049] Silica sol: Shandong Xinrongxin Chemical Technology Co., Ltd., product number: 20231011001.

[0050] Sodium aluminosilicate: CAS number: 1344-00-9.

[0051] Example 1

[0052] A preparation method of the denitration combustion-supporting and acid mist removing additive is as follows:

[0053] Step 1: Mix 150 g of ferric chloride, 100 g of magnesium chloride, 90 g of aluminum chloride with 2 kg of water, and add 500 g of 1 mol / L sodium hydroxide aqueous solution to prepare a crosslinking agent solution;

[0054] Step 2: Mix the modified magnesium saponite with the crosslinking agent solution prepared in Step 1 according to a mass ratio of 1:3, keep it at 50 °C for 20 hours, and then keep it at 100 °C for 20 hours to obtain crosslinked magnesium saponite;

[0055] Step 3: Immerse the crosslinked magnesium saponite in a metal salt solution, and the mass ratio of the crosslinked magnesium saponite to the metal salt solution is 1:10. The metal salt solution contains 0.02 mol / L silver chloride, 0.01 mol / L chloroplatinic acid, 0.01 mol / L palladium chloride, 0.03 mol / L cobalt chloride, 0.05 mol / L nickel chloride, 0.04 mol / L bismuth acetate, 0.06 mol / L zinc chloride, 0.08 mol / L titanium tetrachloride, 0.03 mol / L zirconium chloride, 0.02 mol / L sodium tungstate to obtain the impregnated magnesium saponite;

[0056] Step 4: Calcinate the impregnated sepiolite at 600 °C for 5 hours to obtain the denitrification combustion-supporting and acid mist removing additive.

[0057] The preparation method of the modified sepiolite is as follows:

[0058] S1: Dissolve sodium hydroxide and sodium bicarbonate in water to prepare an alkali solution; the mass ratio of sodium hydroxide, sodium bicarbonate, and water is 1:1.5:15;

[0059] S2: Dissolve magnesium chloride and aluminum chloride in water to prepare a magnesium-aluminum aqueous solution, and the mass ratio of magnesium chloride, aluminum chloride, and water is 1:20:400;

[0060] S3: Dissolve polyethylene glycol ether in water to prepare an aqueous solution containing polyethylene glycol ether, and the mass ratio of polyethylene glycol ether to water is 1:5;

[0061] S4: Under the conditions of constant temperature at 85 °C and stirring, first add 100 g of sodium aluminosilicate to 600 g of the alkali solution to obtain a silicon-containing solution, and then drop 200 g of the magnesium-aluminum aqueous solution and 200 g of the aqueous solution containing polyethylene glycol ether into the silicon-containing solution. After dropping, continue stirring for 3 hours to obtain a reaction solution;

[0062] S5: Add the reaction solution to a crystallization kettle and seal it. Crystallize it at a constant temperature of 160 °C for 15 hours. After crystallization is completed, cool it to room temperature, then perform centrifugation, water washing, vacuum drying at 40 °C for 10 hours, crushing, and sieving through a 100-mesh sieve to obtain the modified sepiolite.

[0063] Example 2

[0064] The preparation method of a denitrification combustion-supporting and acid mist removing additive is basically the same as that in Example 1, and the only difference lies in the different preparation method of the modified sepiolite.

[0065] The preparation method of the modified sepiolite is as follows:

[0066] S1: Dissolve sodium hydroxide and sodium bicarbonate in water to prepare an alkali solution; the mass ratio of sodium hydroxide, sodium bicarbonate, and water is 1:1.5:15;

[0067] S2: Dissolve magnesium chloride and aluminum chloride in water to prepare a magnesium-aluminum aqueous solution, and the mass ratio of magnesium chloride, aluminum chloride, and water is 1:20:400;

[0068] S3: Dissolve polypropylene glycol in water to prepare an aqueous solution containing polypropylene glycol, and the mass ratio of polypropylene glycol to water is 1:5;

[0069] S4. Under the conditions of constant temperature at 85°C and stirring, first add 100 g of sodium aluminosilicate to 600 g of the alkali solution to obtain a silicon-containing solution, and then drop 200 g of the magnesium-aluminum aqueous solution and 200 g of the polypropylene glycol-containing aqueous solution into the silicon-containing solution. After the dropping is completed, continue stirring for 3 hours to obtain a reaction solution;

[0070] S5. Add the reaction solution to a crystallization kettle and seal it. Crystallize it at a constant temperature of 160°C for 15 hours. After the crystallization is completed, cool it to room temperature, and then perform centrifugation, water washing, vacuum drying at 40°C for 10 hours, crushing, and screening through a 100-mesh sieve to obtain modified magnesium saponite.

[0071] Example 3

[0072] The preparation method of a denitrification combustion-supporting and acid mist-removing auxiliary agent is basically the same as that of Example 1, and the only difference is the different preparation method of the modified magnesium saponite.

[0073] The preparation method of the modified magnesium saponite is as follows:

[0074] S1. Dissolve sodium hydroxide and sodium bicarbonate in water to prepare an alkali solution; the mass ratio of sodium hydroxide, sodium bicarbonate, and water is 1:1.5:15;

[0075] S2. Dissolve magnesium chloride and aluminum chloride in water to prepare a magnesium-aluminum aqueous solution, and the mass ratio of magnesium chloride, aluminum chloride, and water is 1:20:400;

[0076] S3. Dissolve polyethylene glycol in water to prepare a polyethylene glycol-containing aqueous solution, and the mass ratio of polyethylene glycol and water is 1:5;

[0077] S4. Under the conditions of constant temperature at 85°C and stirring, first add 100 g of sodium aluminosilicate to 600 g of the alkali solution to obtain a silicon-containing solution, and then drop 200 g of the magnesium-aluminum aqueous solution and 200 g of the polyethylene glycol-containing aqueous solution into the silicon-containing solution. After the dropping is completed, continue stirring for 3 hours to obtain a reaction solution;

[0078] S5. Add the reaction solution to a crystallization kettle and seal it. Crystallize it at a constant temperature of 160°C for 15 hours. After the crystallization is completed, cool it to room temperature, and then perform centrifugation, water washing, vacuum drying at 40°C for 10 hours, crushing, and screening through a 100-mesh sieve to obtain modified magnesium saponite.

[0079] Example 4

[0080] The preparation method of a denitrification combustion-supporting and acid mist-removing auxiliary agent is basically the same as that of Example 1, and the only difference is the different preparation method of the modified magnesium saponite.

[0081] The preparation method of the modified magnesium saponite is as follows:

[0082] S1. Dissolve sodium hydroxide and sodium bicarbonate in water to prepare an alkaline solution; the mass ratio of sodium hydroxide, sodium bicarbonate, and water is 1:1.5:15;

[0083] S2. Dissolve magnesium chloride and aluminum chloride in water to prepare an aqueous solution of magnesium and aluminum; the mass ratio of magnesium chloride, aluminum chloride, and water is 1:20:400;

[0084] S3. Dissolve polyethylene glycol ether in water to prepare an aqueous solution containing polyethylene glycol ether; the mass ratio of polyethylene glycol ether to water is 1:5;

[0085] S4. Under the conditions of constant temperature at 85 °C and stirring, first add 100 g of silica sol to 600 g of the alkaline solution to obtain a silicon-containing solution, and then drop 200 g of the aqueous solution of magnesium and aluminum and 200 g of the aqueous solution containing polyethylene glycol ether into the silicon-containing solution. After dropping, continue stirring for 3 hours to obtain a reaction solution;

[0086] S5. Add the reaction solution to a crystallization kettle and seal it. Crystallize at a constant temperature of 160 °C for 15 hours. After crystallization is completed, cool to room temperature, and then perform centrifugation, water washing, vacuum drying at 40 °C for 10 hours, crushing, and passing through a 100-mesh sieve to obtain modified magnesium saponite.

[0087] Example 5

[0088] The preparation method of a denitration combustion-supporting acid mist removal aid is basically the same as that of Example 1, and the only difference is the different preparation method of the modified magnesium saponite.

[0089] The preparation method of the modified magnesium saponite is as follows:

[0090] S1. Dissolve sodium hydroxide and sodium bicarbonate in water to prepare an alkaline solution; the mass ratio of sodium hydroxide, sodium bicarbonate, and water is 1:1.5:15;

[0091] S2. Dissolve magnesium chloride and aluminum chloride in water to prepare an aqueous solution of magnesium and aluminum; the mass ratio of magnesium chloride, aluminum chloride, and water is 1:20:400;

[0092] S3. Dissolve polyethylene glycol ether in water to prepare an aqueous solution containing polyethylene glycol ether; the mass ratio of polyethylene glycol ether to water is 1:5;

[0093] S4. Under the conditions of constant temperature at 85 °C and stirring, first add 100 g of sodium silicate to 600 g of the alkaline solution to obtain a silicon-containing solution, and then drop 200 g of the aqueous solution of magnesium and aluminum and 200 g of the aqueous solution containing polyethylene glycol ether into the silicon-containing solution. After dropping, continue stirring for 3 hours to obtain a reaction solution;

[0094] S5. Add the reaction solution to a crystallization kettle, seal it, and crystallize it at a constant temperature of 160 °C for 15 hours. After crystallization is completed, cool it to room temperature, then perform centrifugation, washing with water, vacuum drying at 40 °C for 10 hours, crushing, and screening through a 100-mesh sieve to obtain modified magnesium saponite.

[0095] Comparative Example 1

[0096] The preparation method of a denitrification combustion-supporting and acid mist removing aid is as follows:

[0097] Step 1. Mix 150 g of ferric chloride, 100 g of magnesium chloride, 90 g of aluminum chloride with 2 kg of water, and add 500 g of 1 mol / L sodium hydroxide aqueous solution to prepare a crosslinking agent solution;

[0098] Step 2. Add the crosslinking agent solution to the metal salt solution, and the mass ratio of the crosslinking agent solution to the metal salt solution is 1:10. The metal salt solution contains 0.02 mol / L of silver chloride, 0.01 mol / L of chloroplatinic acid, 0.01 mol / L of palladium chloride, 0.03 mol / L of cobalt chloride, 0.05 mol / L of nickel chloride, 0.04 mol / L of bismuth acetate, 0.06 mol / L of zinc chloride, 0.08 mol / L of titanium tetrachloride, 0.03 mol / L of zirconium chloride, and 0.02 mol / L of sodium tungstate to obtain an impregnated complex;

[0099] Step 3. Calcinate the impregnated complex at 600 °C for 5 hours to obtain a denitrification combustion-supporting and acid mist removing aid.

[0100] Test Example 1

[0101] Desulfurization rate test

[0102] The desulfurization rate is a key indicator to measure the performance of the denitrification combustion-supporting and acid mist removing aid, which directly reflects the ability of the aid to capture and convert sulfur oxides (SO X ) during the catalytic cracking process. SO X , including SO 2 and SO 3 , are acidic substances. They react with water vapor in the atmosphere to form acid rain, posing a threat to the environment and human health. Therefore, the level of the desulfurization rate directly determines the acid removal efficiency, that is, the ability to reduce the emissions of these acidic substances. A high desulfurization rate means that the aid can effectively remove more SO X from the flue gas, thereby reducing the emissions of acidic substances and alleviating the acidic pollution to the environment. In short, the improvement of the desulfurization rate directly enhances the acid removal effect and is an important means to achieve the cleanization of industrial processes and environmental protection.

[0103] The principle of action is as follows: The sulfur transfer agent is added to the catalytic cracking unit in the form of an aid, and realizes the removal of SO XAbsorption - release process. Reactions occur in the regenerator as shown in the following (1) - (3):

[0104] S (in coke) + O 2 → SO 2 (90%) + SO 3 (10%) (1)

[0105] 2SO 2 + O 2 → 2SO 3 (2)

[0106] MO + SO 3 → MSO 4 (M represents the metal oxide in the sulfur transfer agent) (3)

[0107] The sulfur transfer agent enters the reactor together with the regenerated catalyst. Under the action of low - carbon hydrocarbons, hydrogen, and stripping steam, the metal sulfate is reduced to release H 2 S, completing the "transfer" process of "sulfur" from the regenerator flue gas to the reactor dry gas. At the same time, the sulfur transfer agent is regenerated and starts the next cycle, as shown in the following (4) - (6):

[0108] MSO 4 + 4H 2 (or hydrocarbons) → MS + 4H 2 O (4)

[0109] MSO 4 + 4H 2 (or hydrocarbons) → MO + H 2 S + 3H 2 O (5)

[0110] MS + H 2 O → MO + H 2 S (in the stripping section) (6)

[0111] The released H 2 S is separated together with the dry gas and processed by the downstream sulfur recovery unit to be recovered in the form of sulfur, thereby achieving the purpose of reducing SO X pollution and turning waste into treasure.

[0112] Select the XTL - 5 type riser recycle fluidized bed FCC experimental device and ensure its cleanliness and integrity. Ensure that all analytical instruments used are calibrated and ready, including the SO 3 analyzer. Use Fushun atmospheric residue (sulfur content 0.2%) and Golmud catalytic stock (sulfur content 0.5%) as reaction raw materials respectively, and the SO 2The concentrations are 110 ppm and 133 ppm respectively. Add 2% of the denitration combustion-supporting acid mist removal additive, and under the lean oxygen two-stage regeneration condition with an oxygen content of only 0.2% in the first stage, continuously operate for 216 h, record the desulfurization rate, and calculate the average value.

[0113] The test results are shown in Table 1.

[0114] Table 1

[0115] Experimental Scheme Desulfurization Rate (%) Example 1 94.3 Example 2 91.5 Example 3 89.7 Example 4 90.5 Example 5 91.2 Comparative Example 1 72.3

[0116] Test Example 2

[0117] Combustion-supporting performance test

[0118] There is a direct relationship between the CO removal rate and the combustion-supporting performance. In the fluid catalytic cracking (FCC) process, the combustion-supporting performance usually refers to the ability of the catalytic additive to promote the further oxidation of CO (carbon monoxide) to CO 2 (carbon dioxide). This ability is crucial for improving the complete combustion of CO in the flue gas, reducing pollutant emissions, and improving energy efficiency. A high CO removal rate usually means that the catalytic additive has good combustion-supporting performance, can effectively promote the oxidation reaction of CO, and accelerate the removal of CO in the flue gas.

[0119] Evaluate the removal efficiency of the denitration combustion-supporting acid mist removal additive for CO in the flue gas under simulated FCC regeneration conditions, that is, the combustion-supporting performance.

[0120] The test equipment is a micro quartz reactor (quartz tube with Φ8×1 mm). KM9106 type flue gas analyzer (for CO analysis). The test conditions are temperature: 680 °C. Gas flow rate: 100 mL / min. Reaction time: 8 hours.

[0121] Weigh 1.0 g of the quartz sand mixed sample containing 3.0% of the denitration combustion-supporting acid mist removal additive. Load the sample into the micro quartz reactor. Heat the reactor to 680 °C under a nitrogen flow. Stop the nitrogen and introduce the proportionally prepared mixed gas. The mixed gas contains SO 2 (1000 mg / m 3 ), NH 3 (800 mg / m 3 ), CO (7% v / v), HCN (130 mg / m 3 ), O 2 (0.5% v / v) and N 2 (the rest of the volume). React for 8 hours and conduct an on-line detection of CO once using the above-mentioned instrument. Calculate the CO removal rate:

[0122] X = (C1 - C2) / C1 × 100%

[0123] Where: X is the CO removal rate of the composition (%), C1 is the content of CO in the gas after reaction (v%), and C2 is the content of CO in the mixed gas before reaction (v%). The test results are shown in Table 2.

[0124] Table 2

[0125] Experimental Scheme CO Removal Rate (%) Example 1 98.4 Example 2 93.7 Example 3 92.8 Example 4 95.2 Example 5 96.5 Comparative Example 1 85.7

[0126] It can be seen from Test Examples 1 to 2 that the denitrification combustion-supporting and acid mist removing additive obtained in Example 1 of the present invention has good desulfurization rate and combustion-supporting performance.

[0127] In Example 1 of the present invention, using polyethylene glycol ether as a modifier shows better desulfurization rate and combustion-supporting performance compared with polypropylene glycol in Example 2 and polyethylene glycol in Example 3. The reason may be related to the molecular structure and properties of polyethylene glycol ether. Since polyethylene glycol ether has more ether bonds (-O-), this may enhance its interaction with the interlayer of saponite, so that during the preparation of modified saponite, the pore structure and specific surface area of the material are more effectively improved, and the number and accessibility of active sites are increased. This structural advantage helps to improve the absorption-release efficiency of the sulfur transfer agent for SO X in the FCC reaction-regeneration system, thereby increasing the desulfurization rate. At the same time, the saponite modified by polyethylene glycol ether may have better thermal stability and stronger metal ion coordination ability, which helps to form more stable metal oxide active components during the calcination process, and then improve the combustion-supporting performance. During the combustion-supporting process, these active components can more effectively catalyze the oxidation of CO and promote its conversion to CO 2 , realizing the efficient removal of CO in the flue gas. In addition, the hydrophilicity and three-dimensional spatial structure of polyethylene glycol ether may help to improve the dispersibility of saponite, reduce the agglomeration phenomenon, and maintain the activity and selectivity of the catalyst, which may also be one of the reasons for the better performance of the additive in Example 1. Therefore, as an effective modifier, polyethylene glycol ether has a positive impact on the structure and performance of saponite through its unique physical and chemical properties, thereby improving the overall performance of the denitrification combustion-supporting and acid mist removing additive.

[0128] Using sodium aluminosilicate as a silicon source in Example 1 shows better desulfurization rate and combustion-supporting performance compared with using silica sol in Example 4 and sodium silicate in Example 5. The reason may be related to the unique chemical and physical properties of sodium aluminosilicate. Sodium aluminosilicate is a silicon source with high activity, and it can more effectively form a stable framework structure with elements such as magnesium and aluminum during the preparation of modified saponite, thereby enhancing the thermal stability and mechanical strength of the material.

[0129] In the crystallization step, sodium aluminosilicate may promote the formation of a more uniform and larger specific surface area microporous structure, which helps to improve the dispersion and accessibility of active sites in the catalytic promoter, thereby enhancing the sulfur oxide absorption capacity and carbon monoxide oxidation efficiency. In addition, the addition of sodium aluminosilicate may also contribute to improving the chemical composition and pore properties of hectorite, providing more active sites for the impregnation of metal salts, and thus enhancing the denitrification and combustion-supporting performance of the promoter. In the actual FCC process, these structural and compositional advantages help the catalytic promoter to more effectively capture and convert SO X and CO, achieving lower pollutant emissions and higher combustion efficiency. Therefore, sodium aluminosilicate, as a silicon source, plays a key role in the preparation of modified hectorite, providing an important material basis for the preparation of an efficient denitrification, combustion-supporting and acid mist removal promoter.

Claims

1. A method for preparing a denitrification combustion-supporting and acid mist removal additive, characterized in that: Here’s how: Step 1, mixing ferric chloride, magnesium chloride, aluminum chloride and water, and adding sodium hydroxide aqueous solution to prepare a crosslinking agent solution; Step 2, mixing the modified magnesium soapstone with the crosslinking agent solution prepared in step 1, heating and heat preservation treatment, to obtain crosslinked magnesium soapstone; Step 3, immersing the cross-linked magnesium saponite in a metal salt solution to obtain the impregnated magnesium saponite; Step 4, roasting the impregnated magnesium soapstone to obtain a denitrification combustion-supporting and acid mist removal auxiliary agent; The metal salt solution contains 0.01-0.03 mol / L silver chloride, 0.005-0.02 mol / L chloroplatinic acid, 0.005-0.02 mol / L palladium chloride, 0.02-0.04 mol / L cobalt chloride, 0.04-0.06 mol / L nickel chloride, 0.03-0.05 mol / L bismuth acetate, 0.05-0.07 mol / L zinc chloride, 0.07-0.09 mol / L titanium tetrachloride, 0.02-0.04 mol / L zirconium chloride, and 0.01-0.03 mol / L sodium tungstate; The preparation method of the modified magnesium soapstone is as follows, in parts by weight: S1. Dissolve sodium hydroxide and sodium bicarbonate in water to prepare alkaline solution; the mass ratio of sodium hydroxide, sodium bicarbonate and water is 0.5~2:1~2:12~18; S2. Dissolve magnesium chloride and aluminum chloride in water to prepare a magnesium-aluminum aqueous solution, wherein the mass ratio of magnesium chloride to aluminum chloride to water is 0.5-2:15-25:300-500; S3, dissolving the polyethylene glycol ether in water to prepare an aqueous solution containing the polyethylene glycol ether, wherein the mass ratio of the polyethylene glycol ether to water is 0.5-2:4-6; S4. Under a constant temperature of 80-90° C. and stirring conditions, first add 80-120 parts of sodium aluminosilicate to 500-700 parts of alkali solution to obtain a silicon-containing liquid, and then dropwise add 150-250 parts of a magnesium aluminum aqueous solution and 150-250 parts of a polyethylene glycol ether aqueous solution to the silicon-containing liquid, and continue stirring for 2-4 hours after the dropwise addition to obtain a reaction solution; S5. Add the reaction solution into a crystallization kettle and seal it. Crystallize it at a constant temperature of 150-180° C. for 10-20 hours. After the crystallization is completed, cool it to room temperature, then centrifuge, wash it with water, vacuum dry it at 30-50° C. for 5-15 hours, crush it, and pass it through a 50-200 mesh sieve to obtain modified magnesium soapstone.

2. The method for preparing the denitration combustion-supporting and acid mist removal additive according to claim 1, characterized in that: The weight proportions of the substances in step 1 are: 120-180 parts of ferric chloride, 80-120 parts of magnesium chloride, 80-100 parts of aluminum chloride, 1800-2200 parts of water, and 400-600 parts of 0.5-2 mol / L sodium hydroxide aqueous solution.

3. The method for preparing the denitration combustion-supporting and acid mist removal auxiliary agent according to claim 1, characterized in that: The mass ratio of the modified magnesium soapstone to the cross-linking agent solution prepared in step 1 is 1:2-4.

4. The method for preparing the denitration combustion-supporting and acid mist removal additive according to claim 1, characterized in that: The mass ratio of the cross-linked magnesium soapstone to the metal salt solution is 1:8-12.

5. The method for preparing the denitration combustion-supporting and acid mist removal auxiliary agent according to claim 1, characterized in that: The temperature-raising and heat-insulating treatment is to maintain the temperature at 40-60° C. for 10-30 hours, and then maintain the temperature at 80-110° C. for 10-30 hours.

6. The method for preparing the denitration combustion-supporting and acid mist removal additive according to claim 1, characterized in that: The calcination temperature is 400-800° C., and the calcination time is 3-8 hours.

7. A denitrification combustion-supporting and acid mist removal additive, characterized in that: The method is prepared according to any one of claims 1 to 6.