An acetylene tail gas recovery process for bdo production

Abstract

The present application relates to gas separation and chemical tail gas recovery technical field, specifically disclose a kind of for BDO production's acetylene tail gas recovery method, the method includes: acetylene tail gas and scrubbing agent are contacted in countercurrent, obtain pretreated tail gas and acetylene-containing scrubbing agent;Pretreated tail gas is pressurized, after gradient cooling, gas-liquid separation, obtain purified compressed tail gas;System pressure is maintained, further cooling, purified compressed tail gas and absorbent are contacted in countercurrent, obtain acetylene-containing absorbent;Acetylene-containing scrubbing agent and acetylene-containing absorbent are desorbed under the action of microwave radiation and ultrasound, after gas-liquid separation, obtain acetylene for BDO production.The present application is designed by the elution-absorption-desorption process for the characteristics of BDO production tail gas, can be efficiently and selectively recovered from acetylene tail gas acetylene, the purity of recovered acetylene is high, significantly reduce the consumption of acetylene.

Description

Technical Field

[0001] This invention relates to the field of gas separation and chemical tail gas recovery technology, specifically to a method for recovering acetylene tail gas in BDO production. Background Technology

[0002] 1,4-Butanediol (BDO), a key bulk chemical raw material, is mainly produced industrially using the Reppe process. In the acetylation reaction step of this process, to prevent the accumulation of inert gases in the system, a portion of acetylene tail gas needs to be continuously emitted. This acetylene tail gas has a complex composition, and in addition to unreacted acetylene (C2H2), it usually contains nitrogen (N2), carbon monoxide (CO), methane (CH4), carbon dioxide (CO2), and trace amounts of high-boiling-point impurities such as formaldehyde. Efficiently recovering and utilizing this tail gas is a key step in achieving cost reduction, efficiency improvement, and green low-carbon development in the BDO production process.

[0003] Currently, the industry's conventional method for treating acetylene tail gas is to directly send it to the flare system for incineration. Although this method is simple to operate, it results in the complete waste of acetylene feedstock, which is converted into carbon dioxide emissions. This not only violates the principles of a circular economy but also increases the carbon footprint of the equipment. With increasingly stringent environmental regulations and rising raw material costs, the resource recovery of acetylene tail gas has become an urgent need for the industry.

[0004] Existing acetylene recovery technologies, such as solvent absorption (using N-methylpyrrolidone or low-temperature methanol) and adsorption methods (such as pressure swing adsorption), have significant limitations when applied to BDO tail gas scenarios. These technologies either suffer from low selectivity of the absorbent for acetylene, difficulty in desorption, and high energy consumption; or are susceptible to the effects of trace amounts of formaldehyde, moisture, and other impurities in the tail gas, leading to absorbent degradation, foaming, or adsorbent poisoning and rapid performance degradation, making long-term stable operation impossible. Furthermore, existing processes often struggle to balance the purity and recovery rate of recovered acetylene, failing to meet the quality requirements of the feed gas for return to the upstream acetylene retort reactor.

[0005] In summary, developing a novel recovery process and technology that addresses the characteristics of acetylene tail gas from BDO production while possessing high selectivity, high recovery rate, and good operational stability is of great significance for improving the overall economic efficiency, resource utilization, and environmental friendliness of BDO plants, and is also an important direction for technological upgrading in this field. Based on the above, this application proposes a method for recovering acetylene tail gas from BDO production. Summary of the Invention

[0006] To address the problems of acetylene resource waste, poor selectivity of recovery processes, high energy consumption, and difficulty in long-term stable operation in existing technologies, this invention proposes a method for acetylene tail gas recovery in BDO production.

[0007] This invention provides a method for recovering acetylene tail gas from BDO production, employing the following technical solution:

[0008] A method for recovering acetylene tail gas from BDO production includes the following steps:

[0009] Step 1: At 30-60℃ and 0.101-0.15MPa, acetylene tail gas is brought into countercurrent contact with atomized detergent to obtain pretreated tail gas and acetylene-containing detergent.

[0010] Step 2: Pressurize the pretreated exhaust gas to 0.5-1.2 MPa, perform gradient cooling, and then separate the gas and liquid to obtain purified compressed exhaust gas;

[0011] Step 3: Maintain the system pressure and further cool to 3-10℃. Then, bring the purified compressed exhaust gas into countercurrent contact with the absorbent to obtain an absorbent containing acetylene.

[0012] Step 4: At 40-70℃ and 10-30KPa, the acetylene-containing detergent and acetylene-containing absorbent are desorbed under microwave radiation and ultrasound, followed by gas-liquid separation to obtain acetylene for BDO production.

[0013] Preferably, in step 1, the liquid-to-gas ratio of detergent to acetylene tail gas is 1.5-4.0 L / m³. 3 .

[0014] Preferably, the atomization process in step 1 is high-voltage electrostatic atomization with a working voltage of 10-30kV.

[0015] Preferably, the detergent in step 1 is prepared by the following method:

[0016] S1. Disperse 1-butyl-3-methylimidazolium chloride in deionized water, add silver acetate while stirring, and react at 40-60℃ in the dark for 6-10 h. After the reaction is completed, centrifuge, take the supernatant, add ethyl acetate for extraction and washing, separate the aqueous phase, and dry under vacuum at 50-70℃ for 6-8 h to obtain 1-butyl-3-methylimidazolium acetate ionic liquid.

[0017] S2. At 60-70℃, 1-butyl-3-methylimidazolium acetate ionic liquid and N-methylpyrrolidone are mixed evenly to obtain the base solution;

[0018] S3. After mixing vinylimidazole monomer and free radical initiator evenly, add it dropwise into the base solution at a uniform rate over 0.5-1h, and continue to keep warm and stir for 3-5h to obtain ionic liquid composite solution;

[0019] S4. Heat the ionic liquid composite solution under vacuum at 80-100℃ for 2-4 hours to remove volatile components and obtain the detergent.

[0020] Preferably, the mass ratio of 1-butyl-3-methylimidazolium chloride, deionized water and silver acetate in S1 is 1:1.5-2.5:0.8-1.0.

[0021] Preferably, the stirring rate in S1 is 200-400 rpm.

[0022] Preferably, the mass ratio of 1-butyl-3-methylimidazolium acetate ionic liquid to N-methylpyrrolidone in S2 is 1:0.8-1.2.

[0023] Preferably, in S3, based on the mass of 1-butyl-3-methylimidazolium acetate ionic liquid as 1, the amount of vinylimidazolium monomer added is 0.1-0.3, and the amount of free radical initiator added is 0.03-0.05.

[0024] Preferably, the free radical initiator in S3 is selected from at least one of azobisisobutyronitrile, azobisisoheptanenitrile, benzoyl peroxide, and lauroyl peroxide.

[0025] Preferably, the free radical initiator in S3 is azobisisobutyronitrile.

[0026] Preferably, the stirring rate in S3 is 300-600 rpm.

[0027] Preferably, the vacuum condition in S4 refers to a vacuum degree of -0.08MPa to -0.1MPa.

[0028] Preferably, the gradient cooling in step 2 refers to cooling the gas sequentially to 25-35℃, 15-25℃, and 10-20℃.

[0029] Preferably, in step 3, the liquid-to-gas ratio of the absorbent to the purified compressed exhaust gas is 2.0-5.0 L / m³. 3 .

[0030] Preferably, the absorbent in step 3 is a mixture of 1-ethyl-1-methylpyrrolidone bis(trifluoromethylsulfonyl)imide and dimethyl carbonate.

[0031] Preferably, the absorbent in step 3 is 1-ethyl-1-methylpyrrolidone bis(trifluoromethylsulfonyl)imide and dimethyl carbonate in a mass ratio of 1:0.5-2.

[0032] Preferably, the microwave radiation in step 4 has a frequency of 2.4-2.5 GHz and a power of 500-800 W.

[0033] Preferably, the ultrasonic parameters in step 4 are an ultrasonic frequency of 20-40 kHz and an ultrasonic power of 300-500 W.

[0034] In summary, the present invention has the following beneficial effects:

[0035] 1. This invention utilizes a washing-absorption-desorption process designed specifically for the characteristics of BDO production tail gas, which enables the efficient and selective recovery of acetylene from acetylene tail gas. The recovered acetylene is of high purity and can be directly returned to the acetylation reactor as a raw material, thereby significantly reducing the consumption of fresh acetylene and improving the economic efficiency of the process from the source.

[0036] 2. This invention uses a modified ionic liquid as a detergent. Its molecular structure is stable and it has excellent chemical inertness to high-boiling-point impurities such as formaldehyde, methanol, and propynyl alcohol present in the exhaust gas. It is not prone to side reactions such as polymerization and degradation. This significantly reduces the problems of performance degradation, foaming, and equipment blockage caused by the accumulation of impurities in traditional solvents, ensuring that the recovery system can operate continuously and stably and significantly improving the operating rate of the device.

[0037] 3. The 1-ethyl-1-methylpyrrolidone bis(trifluoromethanesulfonyl)imide and dimethyl carbonate composite absorbent used in this invention have high selectivity for acetylene and can effectively separate it from inert components in the exhaust gas, thereby obtaining a high-purity product, which provides key support for the long-cycle and low-cost operation of the entire process. Detailed Implementation

[0038] The present invention will be further described in detail below with reference to the embodiments.

[0039] For experiments not specifically described in the examples, the procedures or conditions should be followed according to the conventional experimental procedures described in the literature in this field. Reagents or instruments whose manufacturers are not specified are all commercially available conventional reagent products.

[0040] The key raw materials used in this invention are sourced from the following sources:

[0041] 1-Butyl-3-methylimidazolium chloride: CAS No. 79917-90-1, purchased from Jinan Hengyuan Chemical Co., Ltd.;

[0042] Silver acetate: CAS No. 563-63-3, purchased from Hubei Shuaiyan Ligao Biomedical Co., Ltd.;

[0043] Azobisisobutyronitrile: CAS No. 78-67-1, purchased from Shandong Feihong New Materials Co., Ltd.;

[0044] 1-Vinylimidazole: CAS No. 1072-63-5, purchased from Wuhan Lanabai Pharmaceutical Chemical Co., Ltd.;

[0045] N-Methylpyrrolidone: CAS No. 872-50-4, purchased from Jinan Zekuan Chemical Co., Ltd.;

[0046] 1-Ethyl-1-methylpyrrolidone bis(trifluoromethanesulfonyl)imide: Product No. 713155-50G, purchased from Merck;

[0047] Dimethyl carbonate: Product number D119695-1L, purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.

[0048] Preparation Examples 1-3 and Comparative Preparation Examples 1-2 provide a method for preparing a detergent.

[0049] Preparation Example 1

[0050] Detergent is prepared by the following method:

[0051] S1. Controlling the mass ratio of 1-butyl-3-methylimidazolium chloride, deionized water and silver acetate to 1:1.5:0.8, 1-butyl-3-methylimidazolium chloride was dispersed in deionized water, and silver acetate was added under stirring at 200 rpm. The reaction was carried out at 40 °C in the dark for 10 h. After the reaction was completed, the mixture was centrifuged at 10000 rpm for 10 min, and the supernatant was taken and extracted and washed with ethyl acetate. The aqueous phase was separated and dried under vacuum at 50 °C for 8 h to obtain 1-butyl-3-methylimidazolium acetate ionic liquid.

[0052] S2. Controlling the mass ratio of 1-butyl-3-methylimidazolium acetate ionic liquid to N-methylpyrrolidone to be 1:0.8, the 1-butyl-3-methylimidazolium acetate ionic liquid and N-methylpyrrolidone are mixed evenly at 60℃ to obtain the base solution;

[0053] S3. Taking the mass of 1-butyl-3-methylimidazolium acetate ionic liquid as 1, the amount of vinylimidazolium monomer added is 0.1, and the amount of azobisisobutyronitrile added is 0.03. After the vinylimidazolium monomer and azobisisobutyronitrile are mixed evenly, they are added dropwise to the base solution at a uniform rate within 0.5h. The mixture is then kept warm and stirred for 3h to obtain the ionic liquid composite solution.

[0054] S4. The ionic liquid composite solution is heated at 80℃ and vacuum degree -0.08MPa for 4h to remove volatile components and obtain detergent.

[0055] Preparation Example 2

[0056] Detergent is prepared by the following method:

[0057] S1. Controlling the mass ratio of 1-butyl-3-methylimidazolium chloride, deionized water, and silver acetate to 1:2.1:0.9, 1-butyl-3-methylimidazolium chloride was dispersed in deionized water, and silver acetate was added under stirring at 300 rpm. The reaction was carried out at 50°C in the dark for 8 h. After the reaction was completed, the mixture was centrifuged at 10000 rpm for 10 min, and the supernatant was taken and extracted and washed with ethyl acetate. The aqueous phase was separated and dried under vacuum at 60°C for 7 h to obtain 1-butyl-3-methylimidazolium acetate ionic liquid.

[0058] S2. Controlling the mass ratio of 1-butyl-3-methylimidazolium acetate ionic liquid to N-methylpyrrolidone to 1:1, the 1-butyl-3-methylimidazolium acetate ionic liquid and N-methylpyrrolidone are mixed evenly at 65℃ to obtain the base solution;

[0059] S3. Taking the mass of 1-butyl-3-methylimidazolium acetate ionic liquid as 1, the amount of vinylimidazolium monomer added is 0.2, and the amount of azobisisobutyronitrile added is 0.04. After the vinylimidazolium monomer and azobisisobutyronitrile are mixed evenly, they are added dropwise to the base solution at a uniform rate within 0.8h. The mixture is then kept warm and stirred for 4h to obtain the ionic liquid composite solution.

[0060] S4. The ionic liquid composite solution is heated at 90℃ and vacuum degree -0.09MPa for 3h to remove volatile components and obtain detergent.

[0061] Preparation Example 3

[0062] Detergent is prepared by the following method:

[0063] S1. Controlling the mass ratio of 1-butyl-3-methylimidazolium chloride, deionized water and silver acetate to 1:2.5:1.0, 1-butyl-3-methylimidazolium chloride was dispersed in deionized water, and silver acetate was added under stirring at 400 rpm. The reaction was carried out at 60 °C in the dark for 6 h. After the reaction was completed, the mixture was centrifuged at 10000 rpm for 10 min, and the supernatant was taken and extracted and washed with ethyl acetate. The aqueous phase was separated and dried under vacuum at 70 °C for 6 h to obtain 1-butyl-3-methylimidazolium acetate ionic liquid.

[0064] S2. Controlling the mass ratio of 1-butyl-3-methylimidazolium acetate ionic liquid to N-methylpyrrolidone to be 1:1.2, the 1-butyl-3-methylimidazolium acetate ionic liquid and N-methylpyrrolidone are mixed evenly at 70℃ to obtain the base solution;

[0065] S3. Taking the mass of 1-butyl-3-methylimidazolium acetate ionic liquid as 1, the amount of vinylimidazolium monomer added is 0.3, and the amount of azobisisobutyronitrile added is 0.05. After the vinylimidazolium monomer and azobisisobutyronitrile are mixed evenly, they are added dropwise to the base liquid at a uniform rate within 1 hour. The mixture is then kept warm and stirred for 5 hours to obtain the ionic liquid composite liquid.

[0066] S4. The ionic liquid composite solution is heated at 100℃ and vacuum degree -0.1MPa for 2h to remove volatile components and obtain detergent.

[0067] Comparative Preparation Example 1

[0068] Detergent is prepared by the following method:

[0069] S1. The mass ratio of 1-butyl-3-methylimidazolium chloride to deionized water was controlled at 1:1.5. 1-butyl-3-methylimidazolium chloride was dispersed in deionized water and stirred at 40°C in the dark for 10 h at a stirring speed of 200 rpm. After the reaction was completed, it was dried under vacuum at 50°C for 8 h to obtain the treated 1-butyl-3-methylimidazolium chloride.

[0070] S2. The mass ratio of the treated 1-butyl-3-methylimidazolium chloride to N-methylpyrrolidone is controlled at 1:0.8. The treated 1-butyl-3-methylimidazolium chloride and N-methylpyrrolidone are mixed evenly at 60°C to obtain the base solution.

[0071] S3. Taking the mass of the treated 1-butyl-3-methylimidazolium chloride as 1, the amount of vinylimidazolium monomer added is 0.1, and the amount of azobisisobutyronitrile added is 0.03. After the vinylimidazolium monomer and azobisisobutyronitrile are mixed evenly, they are added dropwise to the base solution at a uniform rate within 0.5h. The mixture is then kept warm and stirred for 3h to obtain the ionic liquid composite solution.

[0072] S4. The ionic liquid composite solution is heated at 80℃ and vacuum degree -0.08MPa for 4h to remove volatile components and obtain detergent.

[0073] Comparative Preparation Example 2

[0074] Detergent is prepared by the following method:

[0075] S1. Controlling the mass ratio of 1-butyl-3-methylimidazolium chloride, deionized water and silver acetate to 1:1.5:0.8, 1-butyl-3-methylimidazolium chloride was dispersed in deionized water, and silver acetate was added under stirring at 200 rpm. The reaction was carried out at 40 °C in the dark for 10 h. After the reaction was completed, the mixture was centrifuged at 10000 rpm for 10 min, and the supernatant was taken and extracted and washed with ethyl acetate. The aqueous phase was separated and dried under vacuum at 50 °C for 8 h to obtain 1-butyl-3-methylimidazolium acetate ionic liquid.

[0076] S2. Controlling the mass ratio of 1-butyl-3-methylimidazolium acetate ionic liquid to N-methylpyrrolidone to be 1:0.8, the 1-butyl-3-methylimidazolium acetate ionic liquid and N-methylpyrrolidone are mixed evenly at 60℃ to obtain the base solution;

[0077] S3. Taking the mass of 1-butyl-3-methylimidazolium acetate ionic liquid as 1, the amount of vinylimidazolium monomer added is 0.1. The vinylimidazolium monomer is added dropwise to the base liquid at a uniform rate over 0.5h, and the mixture is kept warm and stirred for 3h to obtain the ionic liquid composite liquid.

[0078] S4. The ionic liquid composite solution is heated at 80℃ and vacuum degree -0.08MPa for 4h to remove volatile components and obtain detergent.

[0079] Comparative preparation example 3

[0080] Detergent is prepared by the following method:

[0081] S1. Controlling the mass ratio of 1-butyl-3-methylimidazolium chloride, deionized water and silver acetate to 1:1.5:0.8, 1-butyl-3-methylimidazolium chloride was dispersed in deionized water, and silver acetate was added under stirring at 200 rpm. The reaction was carried out at 40 °C in the dark for 10 h. After the reaction was completed, the mixture was centrifuged at 10000 rpm for 10 min, and the supernatant was taken and extracted and washed with ethyl acetate. The aqueous phase was separated and dried under vacuum at 50 °C for 8 h to obtain 1-butyl-3-methylimidazolium acetate ionic liquid.

[0082] S2. Controlling the mass ratio of 1-butyl-3-methylimidazolium acetate ionic liquid to N-methylpyrrolidone to be 1:0.8, the 1-butyl-3-methylimidazolium acetate ionic liquid and N-methylpyrrolidone are mixed evenly at 60℃ to obtain the base solution;

[0083] S3. Taking the mass of 1-butyl-3-methylimidazolium acetate ionic liquid as 1, the amount of azobisisobutyronitrile added is 0.03. Azobisisobutyronitrile is added dropwise to the base solution at a uniform rate over 0.5h, and the mixture is kept warm and stirred for 3h to obtain the ionic liquid composite solution.

[0084] S4. The ionic liquid composite solution is heated at 80℃ and vacuum degree -0.08MPa for 4h to remove volatile components and obtain mixed ionic liquid detergent.

[0085] Example 1

[0086] A method for recovering acetylene tail gas from BDO production includes the following steps:

[0087] Step 1: Control the liquid-to-gas ratio of detergent to acetylene exhaust gas to 1.5 L / m³. 3 At 30°C and 0.101 MPa, acetylene tail gas was countercurrently contacted with detergent (prepared from Preparation Example 1) treated by a 10 kV high-voltage electrostatic atomizer in a packed absorption tower to obtain pretreated tail gas and detergent containing acetylene.

[0088] Step 2: Pressurize the pretreated exhaust gas to 0.5 MPa, then cool it sequentially to 25°C, 15°C, and 10°C, and then separate the gas and liquid to obtain purified compressed exhaust gas.

[0089] Step 3: Control the liquid-to-gas ratio of the absorbent to the purified compressed exhaust gas to be 2.0 L / m³. 3 After maintaining the system pressure and further cooling to 3°C, the purified compressed tail gas is brought into countercurrent contact with the absorbent (including 1-ethyl-1-methylpyrrolidone bis(trifluoromethanesulfonyl)imide and dimethyl carbonate in a mass ratio of 1:0.5) to obtain an absorbent containing acetylene.

[0090] Step 4: At 40℃ and 10KPa, the acetylene-containing detergent and acetylene-containing absorbent are placed in a microwave reactor. Under microwave radiation at a frequency of 2.4GHz and a power of 500W, and supplemented by ultrasonic waves at a frequency of 20kHz and a power of 300W, desorption is performed. After desorption, gas-liquid separation is achieved to obtain acetylene for BDO production.

[0091] Example 2

[0092] A method for recovering acetylene tail gas from BDO production includes the following steps:

[0093] Step 1: Control the liquid-to-gas ratio of detergent to acetylene tail gas to 2.5 L / m³. 3 At 45°C and 0.13 MPa, acetylene tail gas was countercurrently contacted with detergent (prepared from Preparation Example 2) treated by a 20 kV high-voltage electrostatic atomizer in a packed absorption tower to obtain pretreated tail gas and detergent containing acetylene.

[0094] Step 2: Pressurize the pretreated exhaust gas to 0.8 MPa, and then cool it sequentially to 29°C, 20°C, and 15°C. After gas-liquid separation, purified compressed exhaust gas is obtained.

[0095] Step 3: Control the liquid-to-gas ratio of the absorbent to the purified compressed exhaust gas to be 3.0 L / m³. 3， Maintaining the system pressure, further cooling to 6°C, the purified compressed tail gas is brought into countercurrent contact with the absorbent (including 1-ethyl-1-methylpyrrolidone bis(trifluoromethanesulfonyl)imide and dimethyl carbonate in a mass ratio of 1:1) to obtain an absorbent containing acetylene.

[0096] Step 4: At 50℃ and 20KPa, the acetylene-containing detergent and acetylene-containing absorbent are placed in a microwave reactor. Under microwave radiation at a frequency of 2.45GHz and a power of 600W, and supplemented by ultrasonic waves at a frequency of 30kHz and a power of 400W, desorption is performed. After desorption, gas-liquid separation is achieved to obtain acetylene for BDO production.

[0097] Example 3

[0098] A method for recovering acetylene tail gas from BDO production includes the following steps:

[0099] Step 1: Control the liquid-to-gas ratio of detergent to acetylene tail gas to 4.0 L / m³. 3 At 60°C and 0.15 MPa, acetylene tail gas was countercurrently contacted with detergent (prepared from Preparation Example 3) treated by a 30 kV high-voltage electrostatic atomizer in a packed absorption tower to obtain pretreated tail gas and detergent containing acetylene.

[0100] Step 2: Pressurize the pretreated exhaust gas to 1.2 MPa, and then cool it sequentially to 35°C, 25°C, and 20°C. After gas-liquid separation, purified compressed exhaust gas is obtained.

[0101] Step 3: Control the liquid-to-gas ratio of the absorbent to the purified compressed exhaust gas to be 5.0 L / m³. 3， After maintaining the system pressure and further cooling to 10°C, the purified compressed tail gas is brought into countercurrent contact with the absorbent (including 1-ethyl-1-methylpyrrolidone bis(trifluoromethanesulfonyl)imide and dimethyl carbonate in a mass ratio of 1:2) to obtain an absorbent containing acetylene.

[0102] Step 4: At 70℃ and 30KPa, the acetylene-containing detergent and acetylene-containing absorbent are placed in a microwave reactor. Under microwave radiation at a frequency of 2.5GHz and a power of 800W, and supplemented by ultrasonic waves at a frequency of 40kHz and a power of 500W, desorption is performed. After desorption, gas-liquid separation is achieved to obtain acetylene for BDO production.

[0103] To verify the overall performance of the acetylene tail gas recovery method for BDO production provided by this invention, comparative examples 1-6 were set up, wherein:

[0104] Comparative Example 1

[0105] Comparative Example 1 is the same as Example 1, except that the detergent prepared in Preparation Example 1 is replaced with the detergent prepared in Comparative Preparation Example 1. Specifically:

[0106] A method for recovering acetylene tail gas from BDO production includes the following steps:

[0107] Step 1: Control the liquid-to-gas ratio of detergent to acetylene exhaust gas to 1.5 L / m³.3 At 30°C and 0.101 MPa, acetylene tail gas was countercurrently contacted with detergent (prepared from Comparative Preparation Example 1) treated by a 10 kV high-voltage electrostatic atomizer in a packed absorption tower to obtain pretreated tail gas and detergent containing acetylene.

[0108] Step 2: Pressurize the pretreated exhaust gas to 0.5 MPa, then cool it sequentially to 25°C, 15°C, and 10°C, and then separate the gas and liquid to obtain purified compressed exhaust gas.

[0109] Step 3: Control the liquid-to-gas ratio of the absorbent to the purified compressed exhaust gas to be 2.0 L / m³. 3 After maintaining the system pressure and further cooling to 3°C, the purified compressed tail gas is brought into countercurrent contact with the absorbent (including 1-ethyl-1-methylpyrrolidone bis(trifluoromethanesulfonyl)imide and dimethyl carbonate in a mass ratio of 1:0.5) to obtain an absorbent containing acetylene.

[0110] Step 4: At 40℃ and 10KPa, the acetylene-containing detergent and acetylene-containing absorbent are placed in a microwave reactor. Under microwave radiation at a frequency of 2.4GHz and a power of 500W, and supplemented by ultrasonic waves at a frequency of 20kHz and a power of 300W, desorption is performed. After desorption, gas-liquid separation is achieved to obtain acetylene for BDO production.

[0111] Comparative Example 2

[0112] Comparative Example 2 is the same as Example 1, except that the detergent prepared in Preparation Example 1 is replaced with the detergent prepared in Comparative Preparation Example 2. Specifically:

[0113] A method for recovering acetylene tail gas from BDO production includes the following steps:

[0114] Step 1: Control the liquid-to-gas ratio of detergent to acetylene exhaust gas to 1.5 L / m³. 3 At 30°C and 0.101 MPa, acetylene tail gas was countercurrently contacted with detergent (prepared from Comparative Preparation Example 2) treated by a 10 kV high-voltage electrostatic atomizer in a packed absorption tower to obtain pretreated tail gas and detergent containing acetylene.

[0115] Step 2: Pressurize the pretreated exhaust gas to 0.5 MPa, then cool it sequentially to 25°C, 15°C, and 10°C, and then separate the gas and liquid to obtain purified compressed exhaust gas.

[0116] Step 3: Control the liquid-to-gas ratio of the absorbent to the purified compressed exhaust gas to be 2.0 L / m³. 3After maintaining the system pressure and further cooling to 3°C, the purified compressed tail gas is brought into countercurrent contact with the absorbent (including 1-ethyl-1-methylpyrrolidone bis(trifluoromethanesulfonyl)imide and dimethyl carbonate in a mass ratio of 1:0.5) to obtain an absorbent containing acetylene.

[0117] Step 4: At 40℃ and 10KPa, the acetylene-containing detergent and acetylene-containing absorbent are placed in a microwave reactor. Under microwave radiation at a frequency of 2.4GHz and a power of 500W, and supplemented by ultrasonic waves at a frequency of 20kHz and a power of 300W, desorption is performed. After desorption, gas-liquid separation is achieved to obtain acetylene for BDO production.

[0118] Comparative Example 3

[0119] Comparative Example 3 is the same as Example 1, except that the detergent prepared in Preparation Example 1 is replaced with the mixed ionic liquid detergent prepared in Comparative Preparation Example 3. Specifically:

[0120] A method for recovering acetylene tail gas from BDO production includes the following steps:

[0121] Step 1: Control the liquid-to-gas ratio of the mixed ionic liquid detergent to the acetylene tail gas to be 1.5 L / m³. 3 At 30°C and 0.101 MPa, acetylene tail gas was countercurrently contacted in a packed absorption tower with a mixed ionic liquid detergent (prepared from Comparative Preparation Example 3) treated by a 10 kV high-voltage electrostatic atomizer to obtain pretreated tail gas and acetylene-containing detergent.

[0122] Step 2: Pressurize the pretreated exhaust gas to 0.5 MPa, then cool it sequentially to 25°C, 15°C, and 10°C, and then separate the gas and liquid to obtain purified compressed exhaust gas.

[0123] Step 3: Control the liquid-to-gas ratio of the absorbent to the purified compressed exhaust gas to be 2.0 L / m³. 3 After maintaining the system pressure and further cooling to 3°C, the purified compressed tail gas is brought into countercurrent contact with the absorbent (including 1-ethyl-1-methylpyrrolidone bis(trifluoromethanesulfonyl)imide and dimethyl carbonate in a mass ratio of 1:0.5) to obtain an absorbent containing acetylene.

[0124] Step 4: At 40℃ and 10KPa, the acetylene-containing detergent and acetylene-containing absorbent are placed in a microwave reactor. Under microwave radiation at a frequency of 2.4GHz and a power of 500W, and supplemented by ultrasonic waves at a frequency of 20kHz and a power of 300W, desorption is performed. After desorption, gas-liquid separation is achieved to obtain acetylene for BDO production.

[0125] Comparative Example 4

[0126] Comparative Example 4 is the same as Example 1, except that the absorbent is only 1-ethyl-1-methylpyrrolidone bis(trifluoromethanesulfonyl)imide. Specifically:

[0127] A method for recovering acetylene tail gas from BDO production includes the following steps:

[0128] Step 1: Control the liquid-to-gas ratio of detergent to acetylene exhaust gas to 1.5 L / m³. 3 At 30°C and 0.101 MPa, acetylene tail gas was countercurrently contacted with detergent (prepared from Preparation Example 1) treated by a 10 kV high-voltage electrostatic atomizer in a packed absorption tower to obtain pretreated tail gas and detergent containing acetylene.

[0129] Step 2: Pressurize the pretreated exhaust gas to 0.5 MPa, then cool it sequentially to 25°C, 15°C, and 10°C, and then separate the gas and liquid to obtain purified compressed exhaust gas.

[0130] Step 3: Control the liquid-to-gas ratio of the absorbent to the purified compressed exhaust gas to be 2.0 L / m³. 3 After maintaining the system pressure and further cooling to 3°C, the purified compressed tail gas is countercurrently contacted with 1-ethyl-1-methylpyrrolidine onium bis(trifluoromethanesulfonyl)imide to obtain an acetylene-containing absorbent.

[0131] Step 4: At 40℃ and 10KPa, the acetylene-containing detergent and acetylene-containing absorbent are placed in a microwave reactor. Under microwave radiation at a frequency of 2.4GHz and a power of 500W, and supplemented by ultrasonic waves at a frequency of 20kHz and a power of 300W, desorption is performed. After desorption, gas-liquid separation is achieved to obtain acetylene for BDO production.

[0132] Comparative Example 5

[0133] Comparative Example 5 is the same as Example 1, except that the absorbent is only dimethyl carbonate. Details are as follows:

[0134] A method for recovering acetylene tail gas from BDO production includes the following steps:

[0135] Step 1: Control the liquid-to-gas ratio of detergent to acetylene exhaust gas to 1.5 L / m³. 3 At 30°C and 0.101 MPa, acetylene tail gas was countercurrently contacted with detergent (prepared from Preparation Example 1) treated by a 10 kV high-voltage electrostatic atomizer in a packed absorption tower to obtain pretreated tail gas and detergent containing acetylene.

[0136] Step 2: Pressurize the pretreated exhaust gas to 0.5 MPa, then cool it sequentially to 25°C, 15°C, and 10°C, and then separate the gas and liquid to obtain purified compressed exhaust gas.

[0137] Step 3: Control the liquid-to-gas ratio of the absorbent to the purified compressed exhaust gas to be 2.0 L / m³. 3 Maintaining the system pressure, further cooling to 3°C, the purified compressed tail gas is brought into countercurrent contact with dimethyl carbonate to obtain an absorbent containing acetylene.

[0138] Step 4: At 40℃ and 10KPa, the acetylene-containing detergent and acetylene-containing absorbent are placed in a microwave reactor. Under microwave radiation at a frequency of 2.4GHz and a power of 500W, and supplemented by ultrasonic waves at a frequency of 20kHz and a power of 300W, desorption is performed. After desorption, gas-liquid separation is achieved to obtain acetylene for BDO production.

[0139] Comparative Example 6

[0140] Comparative Example 6 is the same as Example 1, except that microwave radiation is not used in step 4. Specifically:

[0141] A method for recovering acetylene tail gas from BDO production includes the following steps:

[0142] Step 1: Control the liquid-to-gas ratio of detergent to acetylene exhaust gas to 1.5 L / m³. 3 At 30°C and 0.101 MPa, acetylene tail gas was countercurrently contacted with detergent (prepared from Preparation Example 1) treated by a 10 kV high-voltage electrostatic atomizer in a packed absorption tower to obtain pretreated tail gas and detergent containing acetylene.

[0143] Step 2: Pressurize the pretreated exhaust gas to 0.5 MPa, then cool it sequentially to 25°C, 15°C, and 10°C, and then separate the gas and liquid to obtain purified compressed exhaust gas.

[0144] Step 3: Control the liquid-to-gas ratio of the absorbent to the purified compressed exhaust gas to be 2.0 L / m³. 3 After maintaining the system pressure and further cooling to 3°C, the purified compressed tail gas is brought into countercurrent contact with the absorbent (including 1-ethyl-1-methylpyrrolidone bis(trifluoromethanesulfonyl)imide and dimethyl carbonate in a mass ratio of 1:0.5) to obtain an absorbent containing acetylene.

[0145] Step 4: At 40℃ and 10KPa, the acetylene-containing detergent and acetylene-containing absorbent are desorbed under the action of ultrasound at a frequency of 20kHz and a power of 300W. After desorption, gas and liquid are separated to obtain acetylene for BDO production.

[0146] The overall performance of the acetylene tail gas recovery methods for BDO production prepared in Examples 1-3 and Comparative Examples 1-5 of this invention was tested respectively.

[0147] 1. Acetylene recovery rate test

[0148] After the device was running stably, simulated BDO acetylene tail gas (30% acetylene, 0.5 MPa) was introduced at a flow rate of 10 L / min. The feed gas, product gas, and purified tail gas were collected simultaneously over 2 hours. The cumulative volume of each gas was measured using a wet gas flow meter with an accuracy of 0.5 grade. The acetylene concentration was analyzed using a gas chromatograph equipped with an FID detector and a Porapak Q column (column temperature 80℃) (sampled once every 30 min). Finally, the measured flow rates were converted to standard state (0℃, 101.325 kPa) volume, and the final result was calculated using the formula: recovery rate (%) = [mass of acetylene in product / (mass of acetylene in product + mass of acetylene in tail gas)] × 100%.

[0149] 2. Acetylene purity and impurity content test

[0150] A gas chromatograph (Agilent 7890B) equipped with a thermal conductivity detector (TCD) and a flame ionization detector (FID) was used. A 100 mL product gas sample was collected using a gas-tight syringe and quantitatively injected into the chromatographic system via a six-way valve (1 mL injection volume). The permanent gases (N2, CO, CO2, CH4) passed through a 5A molecular sieve and a Porapak filter. Analysis was performed using the TCD channel of a Q-series column (carrier gas: high-purity helium, flow rate: 30 mL / min, column temperature program: 50℃ for 5 min, then ramped to 180℃ at 10℃ / min). Organic compounds (acetylene, formaldehyde, etc.) were analyzed using the FID channel of an HP-5 capillary column (carrier gas: high-purity nitrogen, split ratio: 50:1, column temperature program: 40℃ for 2 min, then ramped to 250℃ at 15℃ / min). Quantification was performed using the external standard method (using a multi-component standard gas certified by the National Standards Center, with acetylene concentration of 99.99% and known impurity content). Finally, the acetylene purity (volume fraction) and the content of each impurity were calculated.

[0151] 3. Detergent / Absorbent Cyclic Stability Test

[0152] Under simulated process conditions (40℃, 0.5MPa), 1000mL of fresh detergent (or absorbent) was added to the high-pressure absorption vessel, and simulated acetylene tail gas (acetylene concentration 30%, containing trace amounts of formaldehyde and methanol) was introduced at a flow rate of 2L / min for absorption. After saturation, the process was switched to desorption conditions (60℃, 20kPa, applying ultrasonic waves at a frequency of 28kHz and a power of 500W) for regeneration. This constituted one cycle. After every 10 cycles, 50mL of solvent was precisely sampled from the vessel, and its acetylene equilibrium absorption capacity under standard conditions was measured (using the gravimetric method, measuring the mass difference of the gas before and after absorption using a high-precision balance) and its kinematic viscosity at 40℃ were determined (using an Ubbelohde viscometer, with constant temperature water bath control). This cycle was repeated 50 times, and the absorption capacity and viscosity data were recorded after each cycle. Finally, using the initial values ​​as a baseline, the absorption capacity decay rate and viscosity growth rate at the 50th cycle were calculated.

[0153] The test results are shown in Table 1-2:

[0154] Table 1. Data on acetylene recovery rate and acetylene purity and impurity content in Examples 1-3 and Comparative Examples 1-6.

[0155] Test Project Acetylene recovery rate (%) Acetylene purity (v%) <![CDATA[N2 content (v%)]]> <![CDATA[CH4 content (v%)]]> <![CDATA[CO2 content (v%)]]> CO content (v%) Formaldehyde content (v%) Example 1 99.3 99.778 0.08 0.05 0.06 0.03 0.002 Example 2 99.6 99.782 0.07 0.04 0.08 0.02 0.008 Example 3 99.8 99.875 0.04 0.02 0.05 0.01 0.005 Comparative Example 1 95.2 98.42 0.52 0.31 0.46 0.13 0.16 Comparative Example 2 96.5 98.86 0.44 0.23 0.33 0.08 0.06 Comparative Example 3 94.8 98.04 0.75 0.45 0.56 0.12 0.08 Comparative Example 4 97.1 99.12 0.32 0.27 0.22 0.05 0.02 Comparative Example 5 93.5 97.10 1.16 0.75 0.68 0.16 0.15 Comparative Example 6 92.8 97.93 0.84 0.52 0.41 0.12 0.18

[0156] Table 2. Detergent / absorbent cycle stability test data in Examples 1-3 and Comparative Examples 1-6

[0157] Test Project Absorption capacity decay rate (50th cycle, %) Viscosity growth rate (50th cycle, %) Example 1 3.8 5.8 Example 2 3.1 4.5 Example 3 2.5 3.6 Comparative Example 1 15.6 25.1 Comparative Example 2 12.8 20.5 Comparative Example 3 18.2 28.9 Comparative Example 4 6.5 9.8 Comparative Example 5 10.3 13.5 Comparative Example 6 11.5 15.2

[0158] As shown in Table 1-2, the acetylene tail gas recovery method for BDO production prepared in Examples 1-3 of this invention can achieve an acetylene recovery rate of up to 99.8%, and the purity of the recovered acetylene can reach up to 99.875%. The content of impurities such as nitrogen, methane, and carbon dioxide meets the trace level requirements of subsequent processes. It can effectively remove high-boiling-point impurities such as formaldehyde. At the same time, after 50 cycles of use, the absorption capacity decay rate of the detergent and absorbent is less than 4%, and the viscosity growth rate is less than 6%, demonstrating excellent comprehensive performance and cycle stability.

[0159] As can be seen from Example 1 and Comparative Examples 1, 2, and 3, the detergent prepared in Example 1 has a much better performance than that in Comparative Examples 1-3. The detergents in Comparative Examples 1-3 have poor elution ability and chemical stability for high-boiling-point impurities because they did not undergo anion exchange, did not use free radical initiators, or were not grafted with vinylimidazolium. The acetylene recovery rate and purity decreased significantly. In particular, after 50 cycles, the absorption capacity decay rate and viscosity growth rate increased significantly. This indicates that the specific modification step of the ionic liquid in this invention is the key to ensuring the long-term stable and efficient operation of the detergent.

[0160] As shown in Examples 1 and Comparative Examples 4 and 5, Comparative Example 4, which used only 1-ethyl-1-methylpyrrolidone bis(trifluoromethanesulfonyl)imide, exhibited acceptable stability, but its recovery rate and purity were lower than those of Example 1. Comparative Example 5, which used only dimethyl carbonate, had the worst recovery rate, purity, and stability among all experimental groups. This indicates a synergistic effect between the 1-ethyl-1-methylpyrrolidone bis(trifluoromethanesulfonyl)imide and dimethyl carbonate complex. It utilizes the high selectivity and stability of the ionic liquid for acetylene while simultaneously adjusting the system viscosity and improving mass transfer efficiency through dimethyl carbonate, thereby achieving higher recovery performance.

[0161] As shown in Example 1 and Comparative Example 6, in the absence of microwave radiation, the acetylene recovery rate and purity of Comparative Example 6 are much lower than those of Example 1. This indicates that microwave radiation provides efficient and uniform bulk heating, which is the key energy source for achieving rapid and complete desorption of acetylene from detergents and absorbents. Although ultrasonic action alone can enhance mass transfer at the gas-liquid interface through cavitation, it is insufficient in terms of energy input to break the binding force between acetylene and solvent molecules, resulting in incomplete desorption. A large amount of acetylene remains in the solvent and returns to the absorption system with the lean solution, causing a significant decrease in recovery rate. At the same time, after 50 cycles, the absorption capacity decay rate and viscosity growth rate of Comparative Example 6 are significantly higher than those of Example 1. This indicates that the accumulation of residual acetylene and impurities in the solvent may trigger trace polymerization or side reactions, leading to solvent performance degradation and viscosity increase, which seriously affects the long-term stable operation of the system.

[0162] This specific embodiment is merely an explanation of the present invention and is not intended to limit the invention. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they are within the scope of the claims of the present invention.

Claims

1. A method for recovering acetylene tail gas from BDO production, characterized in that, Includes the following steps: Step 1: At 30-60℃ and 0.101-0.15MPa, acetylene tail gas is brought into countercurrent contact with atomized detergent to obtain pretreated tail gas and acetylene-containing detergent. Step 2: Pressurize the pretreated exhaust gas to 0.5-1.2 MPa, perform gradient cooling, and then separate the gas and liquid to obtain purified compressed exhaust gas; Step 3: Maintain the system pressure and further cool to 3-10℃. Then, bring the purified compressed exhaust gas into countercurrent contact with the absorbent to obtain an absorbent containing acetylene. Step 4: At 40-70℃ and 10-30KPa, the acetylene-containing detergent and acetylene-containing absorbent are desorbed under microwave radiation and ultrasound, and then separated into gas and liquid to obtain acetylene for BDO production.

2. The method for recovering acetylene tail gas from BDO production according to claim 1, characterized in that, In step 1, the liquid-to-gas ratio of detergent to acetylene tail gas is 1.5-4.0 L / m³. 3 .

3. The method for recovering acetylene tail gas from BDO production according to claim 1, characterized in that, The atomization process in step 1 is high-voltage electrostatic atomization, with a working voltage of 10-30kV.

4. The method for recovering acetylene tail gas from BDO production according to claim 1, characterized in that, The detergent in step 1 is prepared by the following method: S1. Disperse 1-butyl-3-methylimidazolium chloride in deionized water, add silver acetate while stirring, and react at 40-60℃ in the dark for 6-10 h. After the reaction is completed, centrifuge, take the supernatant, add ethyl acetate for extraction and washing, separate the aqueous phase, and dry under vacuum at 50-70℃ for 6-8 h to obtain 1-butyl-3-methylimidazolium acetate ionic liquid. S2. At 60-70℃, 1-butyl-3-methylimidazolium acetate ionic liquid and N-methylpyrrolidone are mixed evenly to obtain the base solution; S3. After mixing vinylimidazole monomer and free radical initiator evenly, add it dropwise into the base solution at a uniform rate over 0.5-1h, and continue to keep warm and stir for 3-5h to obtain ionic liquid composite solution; S4. Heat the ionic liquid composite solution under vacuum at 80-100℃ for 2-4 hours to remove volatile components and obtain the detergent.

5. The method for recovering acetylene tail gas from BDO production according to claim 4, characterized in that, The mass ratio of 1-butyl-3-methylimidazolium chloride, deionized water and silver acetate in S1 is 1:1.5-2.5:0.8-1.

0.

6. The method for recovering acetylene tail gas from BDO production according to claim 4, characterized in that, The mass ratio of 1-butyl-3-methylimidazolium acetate ionic liquid to N-methylpyrrolidone in S2 is 1:0.8-1.

2.

7. The method for recovering acetylene tail gas from BDO production according to claim 4, characterized in that, In S3, based on the mass of 1-butyl-3-methylimidazolium acetate ionic liquid as 1, the amount of vinylimidazolium monomer added is 0.1-0.3, and the amount of free radical initiator added is 0.03-0.

05.

8. The method for recovering acetylene tail gas from BDO production according to claim 1, characterized in that, The gradient cooling in step 2 refers to cooling the gas sequentially to 25-35℃, 15-25℃, and 10-20℃.

9. The method for recovering acetylene tail gas from BDO production according to claim 1, characterized in that, The absorbent in step 3 is a mixture of 1-ethyl-1-methylpyrrolidone bis(trifluoromethylsulfonyl)imide and dimethyl carbonate.

10. The method for recovering acetylene tail gas from BDO production according to claim 1, characterized in that, The microwave radiation in step 4 has a frequency of 2.4-2.5 GHz and a power of 500-800 W.