A method for purifying waste gas from crude benzene hydrogenation production and processing

Abstract

The invention discloses a method for purifying waste gas from crude benzene hydrogenation production and processing, which belongs to the technical field of waste gas purification. The method specifically comprises the following steps: introducing dehydrogenated waste gas into a low-temperature tower to obtain methane liquid and purified gas, wherein porous modified polystyrene having affinity for benzene series is prepared, fluorine groups are introduced to improve its tolerance to acidic and alkaline gases, a zirconium 1,4-phthalic acid framework structure is introduced into the structure of the polystyrene to improve the adsorption of benzene series pollutants, and after deacidification and alkali treatment, titanium dioxide particles loaded with platinum and coated with the zirconium 1,4-phthalic acid framework structure whose surface is modified with photosensitive molecules adsorb hydrogen, and remove the hydrogen to obtain hydrogen and dehydrogenated waste gas, and methane-containing waste gas having a large boiling point difference from air components is obtained, and methane and purified gas are obtained after low-temperature removal.

Description

Technical Field

[0001] The present invention relates to the technical field of waste gas purification, and in particular to a method for purifying waste gas produced in the hydrogenation production process of crude benzene. Background Art

[0002] The development of waste gas purification methods for crude benzene hydrogenation processes has evolved from simple treatment to high-efficiency purification technologies. In the early 20th century, crude benzene hydrogenation waste gas was mainly treated by direct discharge or dilution, ignoring environmental pollution. In the mid-20th century, with the increasing awareness of environmental protection, adsorption and absorption methods began to be used to remove benzene series and acid gases, but the efficiency was low and the cost was high. In the 1970s, catalytic combustion technology emerged, and volatile organic compounds in the waste gas were oxidized and decomposed at high temperatures, improving the purification effect, but energy consumption was high and secondary pollution was easily generated. In the 1980s, pressure swing adsorption and membrane separation technologies were introduced, which had higher efficiency for hydrogen and methane separation, marking the beginning of the era of precision separation. In the early 21st century, photocatalytic technology and metal-organic framework materials emerged, using light-induced reactions and pore selectivity to achieve high-efficiency, low-energy purification while reducing acid and alkaline gas corrosion. In recent years, composite technologies integrating physical adsorption, chemical absorption and photocatalysis have significantly improved the separation purity of benzene series, hydrogen and methane, reduced energy consumption and emissions, and met the needs of sustainable development.

[0003] For example, Chinese patent CN102125802B provides a method for recovering and purifying waste gas in crude benzene hydrorefining production, which includes sending the desorption gas in crude benzene hydrorefining production to a desorption gas buffer, and then 3 / h of gas and coke oven gas, send the vent gas from crude benzene hydrorefining production to the vent collection tank, control the vent gas temperature to 35℃, and collect and recover the condensed benzene substances, and then use 70-100m 3 / h is mixed with coke oven gas, and the hydrogen sulfide produced in the crude benzene hydrogenation refining production is sent to the buffer, and the droplets in the hydrogen sulfide are collected and recovered, and then the hydrogen sulfide is discharged at a rate of 10-30m 3 / h is mixed with coke oven gas and purified together, so that the waste gas from the crude benzene hydrogenation refining production is no longer discharged. This not only realizes the comprehensive recycling of resources and reduces the pollution to the environment caused by the discharge of waste gas, but also recovers valuable chemical raw materials such as ammonia, sulfur, benzene and other substances in the waste gas.

[0004] However, the above method only purifies the gas after mixing it with coke oven gas, but it is unable to effectively separate low-boiling-point hydrogen and methane, resulting in these high-value components being mixed into the purified gas, and resource utilization is low. Wash oil absorption and solution absorption are only for polar impurities, and the separation effect on non-polar gases or trace volatile organic compounds is poor, resulting in insufficient purity of the purified gas. The resource utilization is low and downstream applications are limited. In terms of economic efficiency, the high energy consumption, complex equipment and catalyst costs lead to high operating costs, so that the purification level and economy of this method need to be further improved. Summary of the Invention

[0005] The object of the present invention is to provide a method for purifying waste gas from crude benzene hydrogenation production and processing, which is used to solve the technical problem in the prior art that the purification degree and economic efficiency of crude benzene hydrogenation waste gas need to be further improved.

[0006] The object of the present invention can be achieved by the following technical solution: A method for purifying waste gas from crude benzene hydrogenation production and processing, comprising the following steps:

[0007] S1. Add porous polystyrene, zirconium chloride, deionized water and N,N-dimethylformamide to an ultrasonic instrument and ultrasonicate for 10-12 minutes. Then transfer the reaction system to an autoclave. After the autoclave is sealed, the temperature is increased to 100-120° C. and the reaction is kept at this temperature for 24-28 hours. After post-treatment, a modified polystyrene resin is obtained.

[0008] The reaction principle for preparing modified polystyrene resin is: carboxyl induction on the polystyrene surface, growth of zirconium 1,4-phthalic acid framework, N,N-dimethylformamide / water solvent and hydrothermal conditions promote the formation of metal-organic framework crystals, and by integrating the mechanical support of polystyrene and the high adsorption performance of zirconium 1,4-phthalic acid framework, modified polystyrene resin is finally prepared.

[0009] S2, passing the pre-treated waste gas through an adsorption bed loaded with modified polystyrene resin to obtain benzene-free waste gas;

[0010] S3, passing the benzene removal waste gas into the alkaline solution absorption tower and the acid solution absorption tower in sequence to obtain neutral waste gas;

[0011] S4, passing the neutral waste gas into an adsorption bed loaded with a photocatalytic adsorption material to obtain hydrogen-removed waste gas, and degassing the adsorption bed to obtain hydrogen;

[0012] S5. The dehydrogenated waste gas is passed into a low-temperature tower to obtain methane liquid and purified gas.

[0013] Furthermore, in the process of preparing the modified polystyrene resin,

[0014] Furthermore, in step S1, the amount ratio of porous polystyrene, zirconium chloride, deionized water and N,N-dimethylformamide is 9-12 g:3.6-4.0 g:10-12 mL:80-100 mL, and the post-treatment includes: after the reaction is completed, the temperature of the reactor is lowered to room temperature, the reaction liquid is filtered to collect the filter cake, and the filter cake is washed with ethanol and deionized water 3-5 times, and then the filter cake is transferred to a vacuum drying oven at a temperature of 60-80 ° C. and vacuum dried to constant weight to obtain a modified polystyrene resin;

[0015] Furthermore, in step S2, the pre-treatment operation includes: circulating the exhaust gas into a cyclone dust collector for dust removal to obtain intermediate gas I, and circulating the intermediate gas I through a bag filter to obtain dust-removed gas;

[0016] Furthermore, the gas flow rate of the cyclone dust collector is 20,000-40,000 Nm³ / h, and the particle concentration of the exhaust gas is less than 80 mg / Nm 3 The cycle ends and intermediate gas I is obtained; the gas flow rate of the bag filter is 10000-20000Nm³ / h, and the particle concentration of intermediate gas I is less than 8mg / Nm 3 Finally, the cycle is ended to obtain pre-treated exhaust gas;

[0017] Furthermore, in step S2, the adsorption bed has a diameter of 2.0-2.4 m, a height of 1.2-1.5 m, a temperature of 20-30 ° C, a pressure of 0.1-0.2 MPa, a gas volume of 800-1000 m³ / h, and a contact time of 2-3 s; in step S4, the adsorption bed has a diameter of 1.8-2.1 m, a height of 1.0-1.2 m, a temperature of 20-30 ° C, a pressure of 0.1-0.2 MPa, a gas volume of 800-1000 m³ / h, and a contact time of 4-6 s. The degassing treatment includes: after the adsorption is completed, removing the photocatalytic adsorption material, transferring it to the adsorption device for light protection treatment for 10-15 minutes, and then using a vacuum pump to reduce the pressure in the adsorption device to 0.3-0.5 bar for 5-10 minutes to collect hydrogen; in step S5, the temperature of the low-temperature tower is -162 ° C;

[0018] Furthermore, in step S3, the alkali solution in the alkali solution absorption tower is a 2-4 wt% sodium hydroxide aqueous solution, the temperature is 20-40 ° C, the pressure is 0.1-0.2 MPa, and the liquid-gas ratio is 8-10 L / m 3 , gas flow rate is 800-1000m³ / h, gas residence time is 3-5s, alkali solution circulation is 8-10m 3 / h; the acid in the acid absorption tower is a 2-4wt% sulfuric acid aqueous solution, the temperature is 20-30°C, the pressure is 0.1-0.2MPa, and the liquid-gas ratio is 12-15L / m 3, gas flow rate is 800-1000m³ / h, gas residence time is 3-5s, alkali solution circulation is 12-15m 3 / h.

[0019] Furthermore, the preparation method of porous polystyrene comprises the following steps:

[0020] A1. Add the emulsion precursor to a reactor and stir at room temperature at a stirring rate of 60-80 rpm for 10-15 min. Then, add deionized water to the reactor while increasing the stirring rate to 800-1000 rpm. Stir at room temperature for 25-30 min to obtain an emulsion.

[0021] A2. Add the emulsion into a reactor, increase the temperature of the reactor to 60-80°C, keep the temperature and react for 10-12 hours, and then post-treat to obtain porous modified polystyrene.

[0022] The reaction equation for preparing porous modified polystyrene is:

[0023]

[0024] The reaction principle for preparing porous modified polystyrene is as follows: during the dispersion of styrene, vinyl terephthalic acid and m-trifluoromethylstyrene in emulsion droplets, sorbitan oleate forms micelles to stabilize the oil-water interface. Microemulsification is induced by high-speed stirring and the addition of aqueous phase. The monomers in the droplets provide confined space for polymerization, laying the foundation for the porous structure, and forming functionalized polystyrene containing fluorine groups and carboxyl groups through free radical copolymerization. Finally, the formation of the porous structure is induced by the emulsion droplet template and phase separation, and the pores are solidified by washing and drying, finally preparing a porous modified polystyrene with affinity for benzene series and acid-base tolerance.

[0025] Furthermore, in step A1, the ratio of the emulsion precursor to the deionized water is 10-13 g:72-84 mL, wherein the emulsion precursor is obtained by mixing vinyl terephthalic acid, styrene, m-trifluoromethylstyrene, sorbitan oleate, and azobisisobutyronitrile in a ratio of 2-3 g:6-7 g:1-2 g:0.5 g:0.5 g;

[0026] Furthermore, in step A2, the post-treatment includes: after the reaction is completed, the temperature of the reactor is lowered to room temperature, the reaction liquid is filtered to collect the filter cake, the filter cake is washed 3-5 times with ethanol and deionized water, and the filter cake is transferred to a vacuum drying oven at a temperature of 60-80°C, and vacuum dried to constant weight to obtain porous modified polystyrene.

[0027] Furthermore, the preparation method of the photocatalytic adsorption material comprises the following steps:

[0028] B1. Add the titanium source liquid and the platinum source liquid into an autoclave, stir at room temperature for 20-30 minutes, seal the autoclave, and raise the temperature of the autoclave to 180-200° C., keep the temperature for reaction for 10-12 hours, and post-treat to obtain titanium platinum microparticles;

[0029] B2. Add zirconium chloride, terephthalic acid, acetic acid, and N,N-dimethylformamide to an autoclave, stir at room temperature for 10-15 minutes, add titanium platinum microparticles to the autoclave, seal the autoclave, and raise the temperature of the autoclave to 100-120° C., keep the temperature for reaction for 20-24 hours, and perform post-processing to obtain loaded microparticles;

[0030] B3. Tetrakis(4-carboxyphenyl)porphyrin and ethanol were added to a reaction kettle, stirred in the dark for 10-15 minutes, and then loaded microparticles were added to the reaction kettle. The mixture was stirred in the dark for 10-12 hours to obtain a photocatalytic adsorption material.

[0031] The reaction principle for preparing loaded microparticles is as follows: tetrabutyl titanate is hydrolyzed and condensed to form a titanium dioxide skeleton, chloroplatinic acid is thermally reduced to generate platinum particles, and titanium-platinum microparticles with high photocatalytic activity and affinity for hydrogen are synergistically formed. Zirconium ions coordinate and assemble with terephthalic acid to form an organic metal framework, and Ti-OH on the surface of the titanium-platinum microparticles induces the growth of the organic metal framework. By integrating the photocatalytic performance of titanium dioxide and the high adsorption capacity of the organic metal framework, loaded microparticles are finally prepared. Tetrakis(4-carboxyphenyl)porphyrin is anchored to the metal-organic framework or the surface of the titanium dioxide structure through carboxyl coordination. The porphyrin ring captures visible light excited electrons, and synergistically realizes light-induced hydrogen adsorption in the titanium-platinum microparticle structure and the metal-organic framework structure, and finally a photocatalytic adsorption material is prepared.

[0032] Furthermore, in step B1, the amount ratio of the titanium source liquid and the platinum source liquid is 2mL:1mL, wherein the titanium source liquid is obtained by mixing tetrabutyl titanate and anhydrous ethanol in a ratio of 1-2mL:10mL, and the platinum source liquid is obtained by mixing chloroplatinic acid and deionized water in a ratio of 0.1-0.2g:50mL. The post-treatment includes: after the reaction is completed, the temperature of the reactor is lowered to room temperature, the reaction liquid is filtered to collect the filter cake, the filter cake is washed with ethanol and deionized water 3-5 times, and the filter cake is transferred to a vacuum drying oven at a temperature of 60-80°C, and vacuum dried to constant weight to obtain titanium platinum particles;

[0033] Furthermore, in step B2, the ratio of zirconium chloride, terephthalic acid, acetic acid, N,N-dimethylformamide and titanium platinum particles is 2.3-2.4 g:1.6-1.7 g:20 mL:200 mL:5-6 g, and the post-treatment includes: after the reaction is completed, the temperature of the reactor is lowered to room temperature, the reaction liquid is filtered to collect the filter cake, and the filter cake is washed with ethanol and deionized water 3-5 times, and then the filter cake is transferred to a vacuum drying oven at a temperature of 60-80 ° C. and vacuum dried to constant weight to obtain loaded particles;

[0034] Furthermore, in step B3, the dosage ratio of tetrakis(4-carboxyphenyl)porphyrin, ethanol and loaded microparticles is 0.4-0.6g:200mL:4-6g, and the post-treatment includes: after the reaction is completed, the temperature of the reactor is lowered to room temperature, the reaction liquid is filtered to collect the filter cake, and the filter cake is washed 3-5 times with ethanol and deionized water. After that, the filter cake is transferred to a vacuum drying oven at a temperature of 60-80°C and vacuum dried to constant weight to obtain a photocatalytic adsorption material.

[0035] The present invention has the following beneficial effects:

[0036] 1. The modified polystyrene resin prepared by the present invention significantly promotes the efficiency of hydrogen recovery by photocatalytic adsorption materials by removing benzene compounds in crude benzene hydrogenation waste gas. It utilizes the π-π interaction of the benzene ring and the hydrophobic surface to adsorb aromatic hydrocarbons. The fluorine group enhances acid and alkali tolerance. The zirconium 1,4-phthalic acid framework pores capture residual benzene series compounds and purify the waste gas to mainly hydrogen and methane. The removal of benzene series waste gas reduces the competitive interference with the adsorption sites of the photocatalytic material and optimizes the separation environment. The photocatalytic material generates an electric field under light, preferentially adsorbs small molecules of hydrogen, and the pores exclude larger molecules through size screening. The pre-removal of molecules such as methane and benzene series prevents the active sites on the surface of the photocatalytic material from being contaminated, protects the light response ability of the photosensitive molecules, and the sodium hydroxide and sulfuric acid solutions remove acidic and alkaline gases through selective chemical reactions, reducing interference with subsequent adsorption materials. The dehydration adsorption step removes water vapor through physical drying or molecular sieve adsorption to prevent the active sites on the surface of the inorganic structure from being occupied by water molecules, thereby improving the selectivity and desorption efficiency of hydrogen adsorption, enhancing the recovery purity, and reducing the need for material regeneration. This pretreatment significantly improves the hydrogen separation performance and operational stability of the photocatalytic system by purifying the gas phase composition.

[0037] 2. The modified polystyrene prepared by the present invention utilizes its high chemical affinity for benzene series compounds to preferentially adsorb aromatic hydrocarbon molecules through π-π interactions and hydrophobic surfaces, thereby capturing benzene series impurities from the exhaust gas. The zirconium 1,4-phthalic acid framework relies on its high specific surface area and adjustable pore structure to adsorb methane and hydrogen through van der Waals forces and pore screening effects, while restricting the entry of larger molecules. The loaded microparticles are modified with photosensitive molecules to excite electron-hole pairs under light, generating a local electric field, enhancing the highly polarizable adsorption of small hydrogen molecules, and repelling methane and nitrogen and oxygen in the air. Sodium hydroxide solution captures acidic gases such as hydrogen sulfide through acid-base neutralization reactions, and sulfuric acid solution removes alkaline gases such as ammonia through similar reactions, reducing subsequent adsorption loads. At the same time, dehydration treatment removes water vapor and protects the activity of the MOF pores. The remaining methane-containing exhaust gas enters the low-temperature fractionation system, and separation is achieved through step-by-step condensation by utilizing the boiling point difference between methane and nitrogen and oxygen. The synergistic and progressive steps ensure the efficient separation of complex exhaust gas components.

[0038] 3. The modified polystyrene of the present invention is based on inexpensive polymers and is endowed with benzene adsorption capacity through simple chemical modification. The preparation process utilizes mature industrial technology. The zirconium 1,4-phthalic acid framework uses a low-cost precursor. The photocatalytic adsorption material synthesized by the hydrothermal method is excited by visible light or solar energy to drive hydrogen adsorption and desorption. Compared with the refrigeration energy consumption of low-temperature distillation or the high-pressure requirement of pressure swing adsorption, the operating energy consumption is significantly reduced. Sodium hydroxide and sulfuric acid solutions remove impurities through acid-base reactions, and the solution can be recycled by neutralization and regeneration. The dehydration treatment uses physical drying or low-cost molecular sieves to extend the life of the inorganic structure. The separated hydrogen and methane are purified by adsorption and fractionation and can be used as fuel or chemical raw materials. The air components are discharged after purification. The photocatalytic material is regenerated by light or low-temperature treatment, so that the structural stability supports long-term use and reduces the replacement frequency. The modular design of the process allows for miniaturized equipment and flexible adaptation to waste gas treatment needs of different scales, taking into account resource recovery and low emissions. DETAILED DESCRIPTION

[0039] The technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0040] The sorbitan oleate used in the present invention was purchased from Tianjin Xiens Biochemical Technology Co., Ltd. with the product number S-0449256+500ml.

[0041] Example 1

[0042] This embodiment provides a method for preparing a modified polystyrene resin for purifying waste gas from crude benzene hydrogenation production, comprising the following steps:

[0043] Step 1: Prepare emulsion

[0044] Weigh: 20.0g vinyl terephthalic acid, 60.0g styrene, 10.0g m-trifluoromethylstyrene, 5.0g sorbitan oleate and 5.0g azobisisobutyronitrile and mix to obtain an emulsion precursor.

[0045] 100.0 g of the emulsion precursor was weighed and added to a reactor, and stirred at 60 rpm for 10 min at room temperature. 720.0 mL of deionized water was added to the reactor while increasing the stirring rate to 800 rpm. After stirring at room temperature for 25 min, an emulsion was obtained.

[0046] Step ②: Preparation of porous modified polystyrene

[0047] Weigh: 800.0g of emulsion was added to the reactor, the temperature of the reactor was raised to 60°C, and the reaction was kept warm for 10 hours. After the reaction was completed, the temperature of the reactor was lowered to room temperature, the reaction liquid was filtered to collect the filter cake, and the filter cake was washed with ethanol and deionized water 3 times. The filter cake was transferred to a vacuum drying oven at a temperature of 60°C and vacuum dried to constant weight to obtain porous modified polystyrene.

[0048] Step 3: Preparation of modified polystyrene resin

[0049] Weigh: 90.0 g of porous polystyrene, 36.0 g of zirconium chloride, 100.0 mL of deionized water and 800.0 mL of N,N-dimethylformamide, add them to an ultrasonic instrument and sonicate for 10 minutes, then transfer the reaction system to a high-pressure reactor. After the high-pressure reactor is sealed, the temperature is raised to 100°C and kept warm for 24 hours. After the reaction is completed, the temperature of the reactor is lowered to room temperature, the reaction liquid is filtered to collect the filter cake, and the filter cake is washed three times with ethanol and deionized water, and then transferred to a vacuum drying oven at a temperature of 60°C and vacuum dried to constant weight to obtain a modified polystyrene resin.

[0050] Example 2

[0051] This embodiment provides a method for preparing a modified polystyrene resin for purifying waste gas from crude benzene hydrogenation production, comprising the following steps:

[0052] Step 1: Prepare emulsion

[0053] Weigh: 30.0g vinyl terephthalic acid, 70.0g styrene, 20.0g m-trifluoromethylstyrene, 5.0g sorbitan oleate and 5.0g azobisisobutyronitrile and mix to obtain an emulsion precursor.

[0054] 130.0 g of the emulsion precursor was weighed and added to a reactor, and stirred at 80 rpm for 15 min at room temperature. 840.0 mL of deionized water was added to the reactor while increasing the stirring rate to 1000 rpm. After stirring at room temperature for 30 min, an emulsion was obtained.

[0055] Step ②: Preparation of porous modified polystyrene

[0056] Weigh: 960.0g of emulsion was added to the reactor, the temperature of the reactor was raised to 80°C, and the reaction was kept warm for 12 hours. After the reaction was completed, the temperature of the reactor was lowered to room temperature, the reaction liquid was filtered to collect the filter cake, and the filter cake was washed with ethanol and deionized water 5 times. The filter cake was transferred to a vacuum drying oven at a temperature of 80°C and vacuum dried to constant weight to obtain porous modified polystyrene.

[0057] Step 3: Preparation of modified polystyrene resin

[0058] Weigh: 120.0 g of porous polystyrene, 40.0 g of zirconium chloride, 120.0 mL of deionized water and 1000.0 mL of N,N-dimethylformamide, add them to an ultrasonic instrument and ultrasonicate for 12 minutes, then transfer the reaction system to a high-pressure reactor. After the high-pressure reactor is sealed, the temperature is raised to 120°C and kept warm for 28 hours. After the reaction is completed, the temperature of the reactor is lowered to room temperature, the reaction liquid is filtered to collect the filter cake, and the filter cake is washed with ethanol and deionized water 5 times, then transferred to a vacuum drying oven at 80°C and vacuum dried to constant weight to obtain a modified polystyrene resin.

[0059] Example 3

[0060] This embodiment provides a method for preparing a modified polystyrene resin for purifying waste gas from crude benzene hydrogenation production, comprising the following steps:

[0061] Step 1: Prepare emulsion

[0062] Weigh: 25.0g vinyl terephthalic acid, 64.0g styrene, 18.0g m-trifluoromethylstyrene, 5.0g sorbitan oleate and 5.0g azobisisobutyronitrile and mix to obtain an emulsion precursor.

[0063] 110.0 g of the emulsion precursor was weighed and added to a reactor, and stirred at 70 rpm for 12 min at room temperature. 800.0 mL of deionized water was added to the reactor while increasing the stirring rate to 900 rpm. After stirring at room temperature for 27 min, an emulsion was obtained.

[0064] Step ②: Preparation of porous modified polystyrene

[0065] Weigh: 900.0g of emulsion was added to the reactor, the temperature of the reactor was raised to 70°C, and the reaction was kept warm for 12 hours. After the reaction was completed, the temperature of the reactor was lowered to room temperature, the reaction liquid was filtered to collect the filter cake, and the filter cake was washed 4 times with ethanol and deionized water. The filter cake was transferred to a vacuum drying oven at a temperature of 70°C and vacuum dried to constant weight to obtain porous modified polystyrene.

[0066] Step 3: Preparation of modified polystyrene resin

[0067] Weigh: 100.0 g of porous polystyrene, 36.0 g of zirconium chloride, 120.0 mL of deionized water and 900.0 mL of N,N-dimethylformamide, add them to an ultrasonic instrument and sonicate for 12 minutes, then transfer the reaction system to a high-pressure reactor. After the high-pressure reactor is sealed, the temperature is raised to 120°C and kept warm for 28 hours. After the reaction is completed, the temperature of the reactor is lowered to room temperature, the reaction liquid is filtered to collect the filter cake, and the filter cake is washed 4 times with ethanol and deionized water, then transferred to a vacuum drying oven at 70°C and vacuum dried to constant weight to obtain a modified polystyrene resin.

[0068] Example 4

[0069] This embodiment provides a method for preparing a photocatalytic adsorption material for purifying waste gas from crude benzene hydrogenation production, comprising the following steps:

[0070] Step I: Preparation of titanium platinum particles

[0071] Weigh: 60.0 mL of tetrabutyl titanate and 600.0 mL of anhydrous ethanol to obtain a titanium source solution;

[0072] Weigh 6.0 g of chloroplatinic acid and mix with 300.0 mL of deionized water to obtain a platinum source solution.

[0073] Weigh: 600.0mL of titanium source liquid and 300.0mL of platinum source liquid are added to the autoclave. After stirring at room temperature for 20 minutes, the autoclave is sealed and the temperature of the autoclave is raised to 180°C. The reaction is kept warm for 10 hours. After the reaction is completed, the temperature of the autoclave is lowered to room temperature, the reaction liquid is filtered to collect the filter cake, and the filter cake is washed 3 times with ethanol and deionized water. The filter cake is transferred to a vacuum drying oven at a temperature of 60°C and vacuum dried to constant weight to obtain titanium platinum microparticles.

[0074] Step II: Preparation of loaded microparticles

[0075] Weigh: 23.0g zirconium chloride, 16.0g terephthalic acid, 200.0mL acetic acid and 2000.0mL N,N-dimethylformamide are added to a high-pressure reactor. After stirring at room temperature for 10 minutes, 50.0g titanium platinum particles are added to the high-pressure reactor. The high-pressure reactor is sealed and the temperature of the high-pressure reactor is raised to 100°C. The reaction is kept warm for 20 hours. After the reaction is completed, the temperature of the reactor is lowered to room temperature, the reaction liquid is filtered, and the filter cake is collected. After washing the filter cake 3 times with ethanol and deionized water, the filter cake is transferred to a vacuum drying oven at a temperature of 60°C and vacuum dried to constant weight to obtain loaded particles.

[0076] Step III: Preparation of photocatalytic adsorption material

[0077] Weigh: 4.0g of tetrakis(4-carboxyphenyl)porphyrin and 2000.0mL of ethanol were added to the reactor, stirred in the dark for 10 minutes, then 40.0g of loaded microparticles were added to the reactor, stirred in the dark for 10 hours, and after the reaction was completed, the temperature of the reactor was lowered to room temperature, the reaction liquid was filtered to collect the filter cake, and the filter cake was washed 3 times with ethanol and deionized water, and then transferred to a vacuum drying oven at a temperature of 60°C and vacuum dried to constant weight to obtain a photocatalytic adsorption material.

[0078] Example 5

[0079] This embodiment provides a method for preparing a photocatalytic adsorption material for purifying waste gas from crude benzene hydrogenation production, comprising the following steps:

[0080] Step I: Preparation of titanium platinum particles

[0081] Weigh: 120.0 mL of tetrabutyl titanate and 600.0 mL of anhydrous ethanol to obtain a titanium source solution;

[0082] Weigh 12.0 g of chloroplatinic acid and mix with 300.0 mL of deionized water to obtain a platinum source solution.

[0083] Weigh: 600.0mL of titanium source liquid and 300.0mL of platinum source liquid are added to the autoclave. After stirring at room temperature for 30 minutes, the autoclave is sealed and the temperature of the autoclave is raised to 200°C. The reaction is kept warm for 12 hours. After the reaction is completed, the temperature of the autoclave is lowered to room temperature, the reaction liquid is filtered to collect the filter cake, and the filter cake is washed with ethanol and deionized water 5 times. The filter cake is transferred to a vacuum drying oven at a temperature of 80°C and vacuum dried to constant weight to obtain titanium platinum microparticles.

[0084] Step II: Preparation of loaded microparticles

[0085] Weigh: 24.0g zirconium chloride, 17.0g terephthalic acid, 200.0mL acetic acid and 2000.0mL N,N-dimethylformamide are added to a high-pressure reactor. After stirring at room temperature for 15 minutes, 60.0g titanium platinum particles are added to the high-pressure reactor. The high-pressure reactor is sealed and the temperature of the high-pressure reactor is raised to 120°C. The reaction is kept warm for 24 hours. After the reaction is completed, the temperature of the reactor is lowered to room temperature, the reaction liquid is filtered, and the filter cake is collected. After washing the filter cake with ethanol and deionized water 5 times, the filter cake is transferred to a vacuum drying oven at a temperature of 80°C and vacuum dried to constant weight to obtain loaded particles.

[0086] Step III: Preparation of photocatalytic adsorption material

[0087] Weigh: 6.0g of tetrakis(4-carboxyphenyl)porphyrin and 2000.0mL of ethanol were added to the reactor, stirred in the dark for 15 minutes, then 60.0g of loaded microparticles were added to the reactor, stirred in the dark for 12 hours, and after the reaction was completed, the temperature of the reactor was lowered to room temperature, the reaction liquid was filtered to collect the filter cake, and the filter cake was washed 5 times with ethanol and deionized water. The filter cake was transferred to a vacuum drying oven at a temperature of 80°C and vacuum dried to constant weight to obtain a photocatalytic adsorption material.

[0088] Example 6

[0089] This embodiment provides a method for preparing a photocatalytic adsorption material for purifying waste gas from crude benzene hydrogenation production, comprising the following steps:

[0090] Step I: Preparation of titanium platinum particles

[0091] Weigh: 90.0 mL of tetrabutyl titanate and 600.0 mL of anhydrous ethanol to obtain a titanium source solution;

[0092] Weigh 9.0 g of chloroplatinic acid and mix with 300.0 mL of deionized water to obtain a platinum source solution.

[0093] Weigh: 600.0mL of titanium source liquid and 300.0mL of platinum source liquid are added to the autoclave. After stirring at room temperature for 25 minutes, the autoclave is sealed and the temperature of the autoclave is raised to 200°C. The reaction is kept warm for 12 hours. After the reaction is completed, the temperature of the autoclave is lowered to room temperature, the reaction liquid is filtered to collect the filter cake, and the filter cake is washed 4 times with ethanol and deionized water. The filter cake is transferred to a vacuum drying oven at a temperature of 70°C and vacuum dried to constant weight to obtain titanium platinum microparticles.

[0094] Step II: Preparation of loaded microparticles

[0095] Weigh: 24.0g zirconium chloride, 16.0g terephthalic acid, 200.0mL acetic acid and 2000.0mL N,N-dimethylformamide are added to a high-pressure reactor. After stirring at room temperature for 12 minutes, 54.0g titanium platinum particles are added to the high-pressure reactor. The high-pressure reactor is sealed and the temperature of the high-pressure reactor is raised to 120°C. The reaction is kept warm for 21 hours. After the reaction is completed, the temperature of the reactor is lowered to room temperature, the reaction liquid is filtered, and the filter cake is collected. After washing the filter cake with ethanol and deionized water 4 times, the filter cake is transferred to a vacuum drying oven at a temperature of 70°C and vacuum dried to constant weight to obtain loaded particles.

[0096] Step III: Preparation of photocatalytic adsorption material

[0097] Weigh: 5.0g of tetrakis(4-carboxyphenyl)porphyrin and 2000.0mL of ethanol were added to the reactor, stirred in the dark for 12 minutes, then 50.0g of loaded microparticles were added to the reactor, stirred in the dark for 12 hours, and after the reaction was completed, the temperature of the reactor was lowered to room temperature, the reaction liquid was filtered to collect the filter cake, and the filter cake was washed 4 times with ethanol and deionized water, and then transferred to a vacuum drying oven at a temperature of 70°C and vacuum dried to constant weight to obtain a photocatalytic adsorption material.

[0098] Example 7

[0099] This embodiment provides a method for purifying waste gas from crude benzene hydrogenation production and processing, comprising the following steps:

[0100] Step 1: Preparation of benzene removal waste gas

[0101] The exhaust gas is circulated into the cyclone dust collector, the gas flow rate of the cyclone dust collector is 20000Nm³ / h, and the particle concentration of the exhaust gas is less than 80mg / Nm 3 Finally, the cycle is ended to obtain intermediate gas I, which is circulated through the bag filter. The gas flow rate of the bag filter is 10000Nm³ / h, and the particle concentration of intermediate gas I is less than 8mg / Nm 3 Finally, the cycle is ended to obtain pre-treated exhaust gas;

[0102] The pre-treated waste gas was passed into an adsorption bed loaded with the modified polystyrene resin prepared in Example 1. The adsorption bed had a diameter of 2.0 m, a height of 1.2 m, a temperature of 20 ° C, a pressure of 0.1 MPa, and a gas volume of 800 m³ / h to obtain benzene-removed waste gas.

[0103] Step 2: Preparation of neutral waste gas

[0104] The benzene removal waste gas is passed into an alkali liquid absorption tower filled with 2.0wt% sodium hydroxide aqueous solution. The temperature of the alkali liquid absorption tower is 20℃, the pressure is 0.1MPa, and the liquid-gas ratio is 8L / m 3, gas flow rate is 800m³ / h, gas residence time is 3s, alkali solution circulation is 8m 3 / h, and pass the gas into an acid absorption tower filled with 2.0wt% sulfuric acid aqueous solution. The temperature of the acid absorption tower is 20℃, the pressure is 0.1MPa, and the liquid-gas ratio is 12L / m 3 , gas flow rate is 800m³ / h, gas residence time is 3s, alkali solution circulation is 12m 3 / h, to obtain neutral exhaust gas.

[0105] Step 3: Preparation of hydrogen removal waste gas

[0106] The neutral waste gas was passed into an adsorption bed loaded with the photocatalytic adsorption material prepared in Example 4. The adsorption bed had a diameter of 1.8 m, a height of 1.0 m, a temperature of 20 ° C, a pressure of 0.1 MPa, a gas volume of 800 m³ / h, and a contact time of 4 s to obtain dehydrogenated waste gas. After the adsorption was completed, the photocatalytic adsorption material was taken out and transferred to an adsorption device for light-proof treatment for 10 minutes. Then, a vacuum pump was used to reduce the pressure in the adsorption device to 0.3 bar for 5 minutes to collect hydrogen.

[0107] Step 4: Preparation of methane liquid and purified gas

[0108] The dehydrogenation waste gas is passed into a low-temperature tower with a temperature of -162°C to obtain methane liquid and purified gas.

[0109] Example 8

[0110] This embodiment provides a method for purifying waste gas from crude benzene hydrogenation production and processing, comprising the following steps:

[0111] Step 1: Preparation of benzene removal waste gas

[0112] The exhaust gas is circulated into the cyclone dust collector, the gas flow of the cyclone dust collector is 40000Nm³ / h, and the particle concentration of the exhaust gas is less than 80mg / Nm 3 Finally, the cycle is ended to obtain intermediate gas I, which is circulated through the bag filter. The gas flow rate of the bag filter is 20000Nm³ / h, and the particle concentration of intermediate gas I is less than 8mg / Nm 3 Finally, the cycle is ended to obtain pre-treated exhaust gas;

[0113] The pre-treated waste gas was passed into an adsorption bed loaded with the modified polystyrene resin prepared in Example 2. The adsorption bed had a diameter of 2.4 m, a height of 1.5 m, a temperature of 30 ° C, a pressure of 0.2 MPa, and a gas volume of 1000 m³ / h to obtain benzene-removed waste gas.

[0114] Step 2: Preparation of neutral waste gas

[0115] The benzene removal waste gas is passed into an alkali solution absorption tower filled with 4.0wt% sodium hydroxide aqueous solution. The temperature of the alkali solution absorption tower is 40℃, the pressure is 0.2MPa, and the liquid-gas ratio is 10L / m 3 , gas flow rate is 1000m³ / h, gas residence time is 5s, alkali solution circulation is 10m 3 / h, and pass the gas into an acid absorption tower filled with 4.0wt% sulfuric acid aqueous solution. The temperature of the acid absorption tower is 30℃, the pressure is 0.2MPa, and the liquid-gas ratio is 15L / m 3 , gas flow rate is 1000m³ / h, gas residence time is 5s, alkali solution circulation is 15m 3 / h, to obtain neutral exhaust gas.

[0116] Step 3: Preparation of hydrogen removal waste gas

[0117] The neutral waste gas was passed into an adsorption bed loaded with the photocatalytic adsorption material prepared in Example 5. The adsorption bed had a diameter of 2.1 m, a height of 1.2 m, a temperature of 30 ° C, a pressure of 0.2 MPa, a gas volume of 1000 m³ / h, and a contact time of 6 s to obtain hydrogen-free waste gas. After the adsorption was completed, the photocatalytic adsorption material was taken out and transferred to an adsorption device for light-proof treatment for 15 minutes. Then, a vacuum pump was used to reduce the pressure in the adsorption device to 0.5 bar for 10 minutes to collect hydrogen.

[0118] Step 4: Preparation of methane liquid and purified gas

[0119] The dehydrogenation waste gas is passed into a low-temperature tower with a temperature of -162°C to obtain methane liquid and purified gas.

[0120] Example 9

[0121] This embodiment provides a method for purifying waste gas from crude benzene hydrogenation production and processing, comprising the following steps:

[0122] Step 1: Preparation of benzene removal waste gas

[0123] The exhaust gas is circulated into the cyclone dust collector, the gas flow of the cyclone dust collector is 30000Nm³ / h, and the particle concentration of the exhaust gas is less than 80mg / Nm 3 Finally, the cycle is ended to obtain intermediate gas I, which is circulated through the bag filter. The gas flow rate of the bag filter is 15000Nm³ / h, and the particle concentration of intermediate gas I is less than 8mg / Nm 3 Finally, the cycle is ended to obtain pre-treated exhaust gas;

[0124] The pre-treated waste gas was passed into an adsorption bed loaded with the modified polystyrene resin prepared in Example 3. The adsorption bed had a diameter of 2.1 m, a height of 1.5 m, a temperature of 25 ° C, a pressure of 0.2 MPa, and a gas volume of 900 m³ / h to obtain benzene-removed waste gas.

[0125] Step 2: Preparation of neutral waste gas

[0126] The benzene removal waste gas is passed into an alkali solution absorption tower filled with 3.0wt% sodium hydroxide aqueous solution. The temperature of the alkali solution absorption tower is 30℃, the pressure is 0.2MPa, and the liquid-gas ratio is 9L / m 3 , gas flow rate is 900m³ / h, gas residence time is 4s, alkali solution circulation is 9m 3 / h, and pass the gas into an acid absorption tower filled with 3.0wt% sulfuric acid aqueous solution. The temperature of the acid absorption tower is 25℃, the pressure is 0.2MPa, and the liquid-gas ratio is 12L / m 3 , gas flow rate is 900m³ / h, gas residence time is 4s, alkali solution circulation is 15m 3 / h, to obtain neutral exhaust gas.

[0127] Step 3: Preparation of hydrogen removal waste gas

[0128] The neutral waste gas was passed into an adsorption bed loaded with the photocatalytic adsorption material prepared in Example 6. The adsorption bed had a diameter of 2.0 m, a height of 1.2 m, a temperature of 25 ° C, a pressure of 0.2 MPa, a gas volume of 900 m³ / h, and a contact time of 5 s to obtain hydrogen-free waste gas. After the adsorption was completed, the photocatalytic adsorption material was taken out and transferred to an adsorption device for light-proof treatment for 12 minutes. After that, a vacuum pump was used to reduce the pressure in the adsorption device to 0.4 bar for 8 minutes to collect hydrogen.

[0129] Step 4: Preparation of methane liquid and purified gas

[0130] The dehydrogenation waste gas is passed into a low-temperature tower with a temperature of -162°C to obtain methane liquid and purified gas.

[0131] Comparative Example 1

[0132] The difference between this comparative example and Example 9 is that step ③ is omitted during the preparation of the modified polystyrene resin used in step 1.

[0133] Comparative Example 2

[0134] The difference between this comparative example and Example 9 is that step II is omitted during the preparation of the modified polystyrene resin used in step 3.

[0135] Comparative Example 3

[0136] The difference between this comparative example and Example 9 is that step III is omitted during the preparation of the modified polystyrene resin used in step III.

[0137] Performance testing:

[0138] The benzene content, toluene content, and xylene content of the purified gases prepared in Examples 7-9 and Comparative Examples 1-3 were tested with reference to the standard GB 16297-1996 "Integrated Emission Standard of Air Pollutants";

[0139] The ammonia content and hydrogen sulfide content of the purified gases prepared in Examples 7-9 and Comparative Examples 1-3 were tested with reference to the standard GB 14554-1993 "Emission Standard of Odor Pollutants";

[0140] The purity of the hydrogen prepared in Examples 7-9 and Comparative Examples 1-3 was tested with reference to the standard GB / T 3634.2-2011 "Hydrogen Part 2: Pure Hydrogen, High-Purity Hydrogen and Ultrapure Hydrogen";

[0141] The total hydrocarbon content of the purified gas prepared in Examples 7-9 and Comparative Examples 1-3 was tested with reference to the standard HJ 38-2017 "Gas Chromatography Method for Determination of Total Hydrocarbons, Methane and Non-methane Hydrocarbons in Waste Gas from Stationary Pollution Sources", as shown in Table 1.

[0142] Table 1 - Performance test data of each sample

[0143]

[0144] Data Analysis:

[0145] After comparing and analyzing the data in Table 1, it can be found that the benzene content in the purified gas obtained after the exhaust gas treatment of the present invention is 7 mg·m -3 , toluene content is 30mg·m -3 , xylene content is 46 mg·m -3 , ammonia content is 0.4 mg·m -3 , hydrogen sulfide content is 0.01 mg·m -3 , methane content is 0.27 mg·m -3 The purity of the separated hydrogen is 99.99%, and all the data are better than those of the comparative example, indicating that:

[0146] The modified polystyrene resin prepared by the present invention significantly promotes the efficiency of hydrogen recovery by the photocatalytic adsorption material by removing benzene compounds in crude benzene hydrogenation waste gas, utilizes the π-π interaction of the benzene ring and the hydrophobic surface to adsorb aromatic hydrocarbons, and the fluorine group enhances acid and alkali tolerance. The zirconium 1,4-phthalic acid framework pores capture residual benzene series, purifying the waste gas to mainly hydrogen and methane. The waste gas with the benzene series removed reduces the competitive interference with the adsorption sites of the photocatalytic material and optimizes the separation environment. The photocatalytic material generates an electric field under light, preferentially adsorbs small molecules of hydrogen, and the pores exclude larger molecules through size screening. The pre-removal of substances such as methane and benzene prevents the active sites on the surface of the photocatalytic material from being contaminated, protects the light response ability of the photosensitive molecules, and the sodium hydroxide and sulfuric acid solutions remove acidic and alkaline gases through selective chemical reactions, reducing interference with subsequent adsorption materials. The dehydration adsorption step removes water vapor through physical drying or molecular sieve adsorption to prevent the active sites on the surface of the inorganic structure from being occupied by water molecules, thereby improving the selectivity and desorption efficiency of hydrogen adsorption, enhancing the recovery purity, and reducing the need for material regeneration. This pretreatment significantly improves the separation performance and operational stability of the photocatalytic system for hydrogen by purifying the gas phase composition;

[0147] The modified polystyrene prepared by the present invention utilizes its high chemical affinity for benzene series to preferentially adsorb aromatic hydrocarbon molecules through π-π interaction and hydrophobic surface, thereby capturing benzene series impurities from exhaust gas. The zirconium 1,4-phthalic acid framework relies on its high specific surface area and adjustable pore structure to adsorb methane and hydrogen through van der Waals force and pore screening effect, while restricting the entry of larger molecules. The loaded microparticles are modified with photosensitive molecules to excite electron-hole pairs under light, generating a local electric field, enhancing the highly polarizable adsorption of small hydrogen molecules, and repelling methane and nitrogen and oxygen in the air. The sodium hydroxide solution captures acidic gases such as hydrogen sulfide through acid-base neutralization reaction, and the sulfuric acid solution removes alkaline gases such as ammonia through a similar reaction, reducing the subsequent adsorption load. At the same time, dehydration treatment removes water vapor and protects the activity of the MOF pores. The remaining methane-containing exhaust gas enters the low-temperature fractionation system, and separation is achieved through step-by-step condensation by utilizing the boiling point difference between methane and nitrogen and oxygen. The synergistic and progressive steps ensure the efficient separation of complex exhaust gas components.

[0148] The modified polystyrene of the present invention is based on an inexpensive polymer and is endowed with benzene adsorption capacity through simple chemical modification. The preparation process utilizes mature industrial technology. The zirconium 1,4-phthalic acid framework adopts a low-cost precursor. The photocatalytic adsorption material synthesized by the hydrothermal method is excited by visible light or solar energy to drive hydrogen adsorption and desorption. Compared with the refrigeration energy consumption of low-temperature distillation or the high-pressure requirement of pressure swing adsorption, the operating energy consumption is significantly reduced. Sodium hydroxide and sulfuric acid solutions remove impurities through acid-base reactions, and the solution can be recycled by neutralization and regeneration. The dehydration treatment adopts physical drying or low-cost molecular sieves to extend the life of the inorganic structure. The separated hydrogen and methane are purified by adsorption and fractionation and can be used as fuel or chemical raw materials. The air components are discharged after purification. The photocatalytic material is regenerated by light or low-temperature treatment, so that the structural stability supports long-term use and reduces the replacement frequency. The modular design of the process allows for miniaturized equipment and flexible adaptation to the waste gas treatment needs of different scales, taking into account both resource recovery and low emissions.

[0149] The present invention prepares porous modified polystyrene with affinity for benzene series compounds, improves its tolerance to acidic and alkaline gases by introducing fluorine groups, introduces a zirconium 1,4-phthalic acid framework structure into its structure to enhance its adsorption, absorbs acidic gases such as hydrogen sulfide through a sodium hydroxide aqueous solution, absorbs alkaline gases through a sulfuric acid solution, and dehydrates the product. The hydrogen is then adsorbed and removed by platinum-loaded titanium dioxide particles coated with a zirconium 1,4-phthalic acid framework structure with surface-modified photosensitive molecules to obtain hydrogen and dehydrogenated waste gas, and finally obtains methane-containing waste gas with a boiling point significantly different from that of air components. After low-temperature removal, methane and purified gas are obtained.

[0150] The preferred embodiments of the present invention disclosed above are intended only to help illustrate the present invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the present invention to specific embodiments. Obviously, many modifications and variations are possible based on the contents of this specification. These embodiments are selected and described in detail in this specification to better explain the principles and practical applications of the present invention, thereby enabling those skilled in the art to better understand and utilize the present invention. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A method for purifying waste gas from crude benzene hydrogenation production and processing, characterized in that: The following steps are involved: S1. Add porous polystyrene, zirconium chloride, deionized water and N,N-dimethylformamide to an ultrasonic instrument and ultrasonicate for 10-12 minutes. Then transfer the reaction system to an autoclave. After the autoclave is sealed, the temperature is increased to 100-120° C. and the reaction is kept at this temperature for 24-28 hours. After post-treatment, a modified polystyrene resin is obtained. S2, passing the pre-treated waste gas through an adsorption bed loaded with modified polystyrene resin to obtain benzene-free waste gas; S3, passing the benzene removal waste gas into the alkaline solution absorption tower and the acid solution absorption tower in sequence to obtain neutral waste gas; S4, passing the neutral waste gas into an adsorption bed loaded with a photocatalytic adsorption material to obtain hydrogen-removed waste gas, and degassing the adsorption bed to obtain hydrogen; S5, passing the dehydrogenation waste gas into a low-temperature tower to obtain methane liquid and purified gas; In step S1, the method for preparing porous polystyrene comprises the following steps: A1, the emulsion precursor was added to the reactor and stirred, and the stirring speed (S.S.) was 60-80 rpm for 10-15 min at room temperature. The stirring speed (S.S.) was increased to 800-1000 rpm when deionized water was added to the reactor. After stirring for 25-30 min at room temperature, an emulsion was obtained. The amount ratio of the emulsion precursor and the deionized water was 10-13 g: 72-84 mL. The emulsion precursor was mixed with vinyl terephthalic acid, styrene, m-trifluoromethylstyrene, sorbitan oleate and azobisisobutyronitrile in the amount ratio of 2-3 g: 6-7 g: 1-2 g: 0.5 g: 0.5 g. A2. Add the emulsion into a reactor, increase the temperature of the reactor to 60-80°C, keep the temperature and react for 10-12 hours, and then perform post-processing to obtain porous modified polystyrene.

2. The method for purifying waste gas from crude benzene hydrogenation production and processing according to claim 1, characterized in that: In step S1, the usage ratio of porous polystyrene, zirconium chloride, deionized water and N,N-dimethylformamide is 9-12 g:3.6-4.0 g:10-12 mL:80-100 mL; in step S2, the adsorption bed has a diameter of 2.0-2.4 m, a height of 1.2-1.5 m, a temperature of 20-30° C., a pressure of 0.1-0.2 MPa, a gas volume of 800-1000 m³ / h, and a contact time of 2-3 s; in step S4, the adsorption bed has a diameter of 1.8-2.1 m, a height of 1.0-1.2 m, a temperature of 20-30° C., a pressure of 0.1-0.2 MPa, a gas volume of 800-1000 m³ / h, and a contact time of 4-6 s; and in step S5, the temperature of the cryogenic tower is -162° C.

3. The method for purifying waste gas from crude benzene hydrogenation production and processing according to claim 1, characterized in that: In step S3, the alkali solution in the alkali solution absorption tower is 2-4wt% sodium hydroxide aqueous solution, the temperature is 20-40°C, the pressure is 0.1-0.2MPa, and the liquid-gas ratio is 8-10L / m 3 , gas flow rate is 800-1000m³ / h, gas residence time is 3-5s, alkali solution circulation is 8-10m 3 / h; the acid in the acid absorption tower is a 2-4wt% sulfuric acid aqueous solution, the temperature is 20-30°C, the pressure is 0.1-0.2MPa, and the liquid-gas ratio is 12-15L / m 3 , gas flow rate is 800-1000m³ / h, gas residence time is 3-5s, alkali solution circulation is 12-15m 3 / h.

4. The method for purifying waste gas from crude benzene hydrogenation production and processing according to claim 1, characterized in that: The preparation method of the photocatalytic adsorption material comprises the following steps: B1. Add the titanium source liquid and the platinum source liquid into an autoclave, stir at room temperature for 20-30 minutes, seal the autoclave, and raise the temperature of the autoclave to 180-200° C., keep the temperature for reaction for 10-12 hours, and post-treat to obtain titanium platinum microparticles; B2. Add zirconium chloride, terephthalic acid, acetic acid, and N,N-dimethylformamide to an autoclave, stir at room temperature for 10-15 minutes, add titanium platinum microparticles to the autoclave, seal the autoclave, and raise the temperature of the autoclave to 100-120° C., keep the temperature for reaction for 20-24 hours, and perform post-processing to obtain loaded microparticles; B3. Tetrakis(4-carboxyphenyl)porphyrin and ethanol were added to a reaction kettle, stirred in the dark for 10-15 minutes, and then loaded microparticles were added to the reaction kettle. The mixture was stirred in the dark for 10-12 hours to obtain a photocatalytic adsorption material.

5. The method for purifying waste gas from crude benzene hydrogenation production and processing according to claim 4, characterized in that: In step B1, the amount ratio of titanium source liquid and platinum source liquid is 2mL:1mL, wherein the titanium source liquid is obtained by mixing tetrabutyl titanate and anhydrous ethanol in a ratio of 1-2mL:10mL, and the platinum source liquid is obtained by mixing chloroplatinic acid and deionized water in a ratio of 0.1-0.2g:50mL; in step B2, the amount ratio of zirconium chloride, terephthalic acid, acetic acid, N,N-dimethylformamide and titanium platinum particles is 2.3-2.4g:1.6-1.7g:20mL:200mL:5-6g; in step B3, the amount ratio of tetrakis(4-carboxyphenyl)porphyrin, ethanol and loaded particles is 0.4-0.6g:200mL:4-6g.

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