A method for separating an acid dichloroethane mixture

Abstract

This invention belongs to the field of acidic dichloroethane mixture separation and treatment technology, specifically relating to a method for separating and treating acidic dichloroethane mixtures. A method for separating and treating acidic dichloroethane mixtures includes the following steps: (1) Primary water cooling: Initial process tail gas is introduced into a 170m³ water bath. 3 / h~190m 3 A screw vacuum pump with a compression rate of / h compresses the compressor, stabilizing the outlet pressure at 0.05MPa~0.15MPa. The compressor is then fed into a primary water-cooled condenser, which is 10m³. 3 (1) Single-channel graphite condenser; (2) Secondary water cooling: After primary water cooling, the process tail gas enters the secondary water-cooled condenser, which is 15m. 3 Single-channel graphite condenser, controlling the chilled water to be stable at 0℃; (3) Three-stage water cooling: the process tail gas after the two-stage water cooling is introduced into the three-stage water cooling condenser, the three-stage water cooling condenser is 15m 3 Single-channel graphite condenser, chilled water is stable at -5℃; (4) Deep cooling: the process tail gas after three-stage water cooling is introduced into the deep cooling tower from the bottom and discharged from the top of the deep cooling tower. The temperature of the deep cooling tower is -30℃; (5) Purification.

Description

Technical Field

[0001] This invention belongs to the field of separation and treatment technology of acidic dichloroethane mixtures, and specifically relates to a method for separating and treating acidic dichloroethane mixtures. Background Technology

[0002] In the industrial production of ethephon, the post-treatment of the acidic dichloroethane mixture, a production residue, is an important step. This post-treatment requires the separation of the various components of the acidic dichloroethane mixture, which include dichloroethane, water, dichloroethyl ether, hydrogen chloride, and 2-chloroethylphosphonate.

[0003] In the industry, the separation of dichloroethane from acidic dichloroethane mixtures often employs a single-stage water cooling method, which does not allow for multiple cycles of the cold source. This results in low dichloroethane recovery rates and significant waste of the low-temperature cold source. To address these issues, this invention aims to provide a method for separating acidic dichloroethane mixtures. Summary of the Invention

[0004] The purpose of this invention is to provide a method for separating acidic dichloroethane mixtures to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: A method for separating and processing a mixture of acidic dichloroethane includes the following steps: (1) Primary water cooling: The initial process exhaust gas is introduced into a 170m³ water cooling system. 3 / h~190m 3 The compressor is compressed by a screw vacuum pump with a capacity of / h, and the outlet pressure is stabilized at 0.05MPa~0.15MPa. The compressor is then fed into a first-stage water-cooled condenser, which is a 10m3 single-channel graphite condenser. (2) Secondary water cooling: The process exhaust gas after primary water cooling enters the secondary water-cooled condenser, which is 15m². 3 A single-channel graphite condenser controls the chilled water temperature to remain stable at 0°C. (3) Three-stage water cooling: The process exhaust gas after the two-stage water cooling is introduced into a three-stage water-cooled condenser, which is 15m³. 3 A single-channel graphite condenser controls the chilled water temperature to remain stable at -5°C. (4) Deep cooling: The process tail gas after three-stage water cooling is introduced into the deep cooling tower from the bottom and further discharged from the top of the deep cooling tower. The temperature of the deep cooling tower is -30℃. (5) Purification: The process tail gas after cryogenic treatment is passed into a purification device for purification; the cryogenic tower includes a main cylinder, which is divided into an air-cooled section and a liquid-cooled section. The liquid-cooled section is located below the air-cooled section and is equipped with coolant. The air-cooled section is equipped with an air-cooled baffle; the air-cooled section is divided into an air-cooled chamber one and an air-cooled chamber two by the air-cooled baffle; the lower part of the side wall of the air-cooled chamber one is equipped with a condenser inlet pipe one, and the upper part of the side wall of the air-cooled chamber two is equipped with a condenser outlet pipe one; the interior of the air-cooled chamber one is equipped with several left heat exchange tubes, and the tops of the several left heat exchange tubes are connected to a common connection. The air-cooled chamber has a second condenser inlet pipe, and the bottom of the plurality of left heat exchange pipes is connected to a second condenser outlet pipe, which is located at the liquid cooling section. The air-cooled chamber has a plurality of right heat exchange pipes inside, and the top of the plurality of right heat exchange pipes is connected to a third condenser inlet pipe, and the bottom of the plurality of right heat exchange pipes is connected to a third condenser outlet pipe, which is located at the liquid cooling section. The first condenser outlet pipe and the second condenser inlet pipe are respectively connected to the bottom side line and the top side line of the purifier, and the liquid nitrogen source and the third condenser inlet pipe are respectively connected to the top and bottom of the purifier.

[0006] Preferably, a thermal temperature controller is provided at the connection passage between the purifier and the second condenser air inlet pipe, and a thermal temperature controller is provided at the connection passage between the purifier and the third condenser air inlet pipe.

[0007] Preferably, both the left and right heat exchange tubes are spiral tubes.

[0008] Preferably, the first air-cooled chamber is provided with three left heat exchange tubes, and the second air-cooled chamber is provided with three right heat exchange tubes.

[0009] Preferably, the coolant level is flush with the bottom of the air-cooled baffle.

[0010] Preferably, in step (2), a 10m³ chilled water vertical circulation pump is used. 3 The flow rate is controlled by adjusting the flow rate and the return flow rate of chilled water at -14℃ to stabilize the chilled water temperature at 0℃.

[0011] Preferably, in step (3), a 5m vertical circulating pump for chilled water is used. 3 The flow rate is controlled by adjusting the flow rate and the return flow rate of chilled water at -14℃ to stabilize the chilled water temperature at -5℃.

[0012] Preferably, in step (4), the temperature of the cryogenic tower is controlled by liquid nitrogen at -60°C, so that the temperature of the cryogenic tower is stabilized at -30°C.

[0013] Compared with the prior art, the beneficial effects of the present invention are: (1) The present invention provides a method for separating acidic dichloroethane mixtures, which adopts a multi-stage water cooling condensation method to cool the process gas in a stepwise manner, gradually reducing the water cooling condensation temperature of the process gas, which can effectively reduce the reaction intensity of single-step condensation, and at the same time, the minimum temperature requirement for water cooling condensation is lower. Compared with single-stage water cooling condensation, the minimum temperature of multi-stage water cooling condensation is higher, the required cost is lower, and energy consumption can be saved. (2) The present invention provides a method for separating acidic dichloroethane mixtures. In the purification stage, a multi-cycle condensation purification process is adopted, which enables the cold source to pass through the purifier for the first time, providing an ambient temperature for the purification reaction in the purifier. After the purifier is used, the cold source after heat exchange is further introduced into the cryogenic tower. Since the temperature requirement of the cryogenic tower is low, the cold source after heat exchange can be further reused in the cryogenic tower, which greatly improves the utilization efficiency of the cold source. (3) The present invention provides a method for separating acidic dichloroethane mixtures. The process gas is condensed by three-stage water cooling and enters the cryogenic tower twice. The temperature of the condensate in the cryogenic tower is used as a reference to calibrate the temperature of the process gas before and after purification, which is beneficial for heat recovery. After temperature calibration, the output process gas temperature is more environmentally friendly. At the same time, the process gas before and after purification passes through the condensate in the cryogenic tower multiple times, which can ensure that the temperature of the condensate is relatively stable and reduce the energy consumption and cost required for condensate cold preservation. Attached Figure Description

[0014] Figure 1 This is a process route diagram for the present invention; Figure 2 This is a schematic diagram of the structure of the present invention; Figure 3 This is a structural diagram of the cryogenic tower in this invention; Figure 4 This is a cross-sectional view of the cryogenic tower in this invention; In the diagram: 1. Cryogenic tower; 2. Thermal temperature controller; 3. Purifier; 4. Liquid nitrogen source; 5. Main cylinder; 6. Air-cooled section; 7. Liquid-cooled section; 9. Air-cooled baffle; 10. Air-cooled chamber one; 11. Air-cooled chamber two; 12. Left heat exchange tube; 13. Condensate inlet pipe two; 14. Right heat exchange tube; 15. Condensate inlet pipe three; 16. Condensate inlet pipe one; 17. Condensate outlet pipe one. Detailed Implementation

[0015] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Example 1

[0016] The process exhaust gas from the workshop (dichloroethane content 20034 mg / m³) 3 ), through 180m 3 The compressor is compressed by a screw vacuum pump at a pressure of / h, and the outlet pressure is stabilized at 0.1MPa before entering the first-stage water-cooled condenser (10m). 3 (Single-channel graphite condenser) The condensate contains 14.6% dichloroethane and 72.7% water.

[0017] The process exhaust gas after primary water cooling enters the secondary chilled water-cooled condenser (15m). 3 Single-channel graphite condenser), via a chilled water vertical circulation pump (10m³). 3 The system controls the return flow of chilled water (-14℃) to keep the chilled water temperature stable at 0℃. The condensate contains 48.6% dichloroethane and 43.1% water.

[0018] The process exhaust gas after secondary condensation enters the tertiary condenser (15m). 3 Single-channel graphite condenser), via a chilled water vertical circulation pump (5m³). 3 The system controls the return flow of chilled water (-14℃) to keep the chilled water temperature stable at -5℃. The condensate contains 88.4% dichloroethane and 6.7% water.

[0019] After three stages of condensation, the process tail gas enters the cryogenic tower (height: 5.4 meters, width: 0.4 meters, material: stainless steel) from the bottom side stream and exits from the top side stream. The cryogenic tower temperature is controlled by liquid nitrogen (-60℃) entering the purifier at the top, which stabilizes the temperature at -30℃. The vaporized liquid nitrogen gas is used in the workshop. The condensate in the cryogenic tower contains 99.1% dichloroethane and 0.1% water.

[0020] The cryogenic tower 1 includes a main cylinder 5, which is divided into an air-cooled section 6 and a liquid-cooled section 7. The liquid-cooled section 7 is located below the air-cooled section 6 and contains coolant. An air-cooled baffle 9 is installed inside the air-cooled section 6, dividing it into an air-cooled chamber 10 and an air-cooled chamber 2 11. The bottom of the baffle 9 is flush with the surface of the coolant. The air-cooled chamber 10 contains three left heat exchange tubes 12. A condenser inlet pipe 2 13 is connected to the top of each of the three left heat exchange tubes 12, and a condenser outlet pipe 2 is connected to the bottom of each of the three left heat exchange tubes 12. The condenser outlet pipe 2 is located in the liquid-cooled section 7. The air-cooled chamber 2 11 contains three right heat exchange tubes 14. A condenser inlet pipe 3 15 is connected to the top of each of the three right heat exchange tubes 14, and a condenser outlet pipe 3 is connected to the bottom of each of the three right heat exchange tubes 14. The condenser outlet pipe 3 is located in the liquid-cooled section 7. To enhance the heat exchange efficiency of the left heat exchange tube 12 and the right heat exchange tube 14, both are spiral tubes. Condensate outlet pipe one 17 and condensate outlet pipe two are connected to the bottom and top side lines of the purifier 3, respectively. Liquid nitrogen source 4 and condensate inlet pipe three 15 are connected to the top and bottom of the purifier 3, respectively. For temperature control, a thermal temperature controller 2 is installed at the connection point between the purifier 3 and condensate inlet pipe two 13, and at the connection point between the purifier 3 and condensate inlet pipe three 15.

[0021] A condenser inlet pipe 16 is provided on the lower side wall of air-cooled chamber 10, and a condenser outlet pipe 17 is provided on the upper side wall of air-cooled chamber 11. Process tail gas is introduced through the condenser inlet pipe 16. After the gas pressure in air-cooled chamber 10 reaches a certain value, the process tail gas escapes from air-cooled chamber 10 through the coolant to air-cooled chamber 11. During this process, the process tail gas is pre-cooled by the coolant. After entering air-cooled chamber 11, it is further pre-cooled by three right heat exchange pipes 14 inside air-cooled chamber 11. After being pre-cooled by cryogenic tower 1, the process tail gas is discharged to purifier 3 through condenser outlet pipe 17. Purifier 3 purifies the process tail gas. During this process, liquid nitrogen source 4 connected to purifier 3 outputs liquid nitrogen to purifier 3. The liquid nitrogen is used to further reduce the temperature of the process tail gas and promote the purification reaction. Furthermore, the liquid nitrogen from the purifier 3 is transferred to the three right heat exchange tubes 14 of the cryogenic tower 1. The upper part of the right heat exchange tubes 14 is located in the second air-cooled chamber 11, and the lower part is located in the liquid-cooled section 7. The right heat exchange tubes 14 located in the second air-cooled chamber 11 can pre-cool the process exhaust gas entering the purifier 3, and the right heat exchange tubes 14 located in the liquid-cooled section 7 can reduce the temperature of the coolant. The process exhaust gas after purification by the purifier 3 has a low temperature. The temperature is increased by the thermal temperature controller 2 and the cryogenic tower 1. The low-temperature process exhaust gas enters the first air-cooled chamber 10 through the left heat exchange tube 12, where it is pre-cooled. Furthermore, the process exhaust gas in the left heat exchange tube 12 exchanges heat with the coolant in the liquid-cooled section 7. Finally, the warm purified process exhaust gas is discharged from the second condensate outlet pipe.

[0022] Liquid nitrogen (-196℃) in liquid nitrogen source 4 is drawn from purifier 3 (5m) 3 (Material: Stainless steel) The gas enters from the top and exits from the bottom into the cryogenic tower. The process exhaust gas exiting the cryogenic tower enters from the bottom side of the purifier, exits from the top side, and then enters from the top of the cryogenic tower for preheating. The preheated process exhaust gas exits from the bottom side of the cryogenic tower, at which point the dichloroethane content in the process exhaust gas has decreased to 103 mg / m³. 3 . Example 2

[0023] The process exhaust gas from the workshop (dichloroethane content 20034 mg / m³) 3 ), through 170m 3 The compressor is compressed by a screw vacuum pump at a pressure of / h, and the outlet pressure is stabilized at 0.05MPa before entering the first-stage water-cooled condenser (10m). 3 (Single-channel graphite condenser) The condensate contains 13.2% dichloroethane and 74.2% water.

[0024] The process exhaust gas after primary water cooling enters the secondary chilled water-cooled condenser (15m). 3 Single-channel graphite condenser), via a chilled water vertical circulation pump (10m³). 3The system controls the return flow of chilled water (-14℃) to keep the chilled water temperature stable at 0℃. The condensate contains 46.5% dichloroethane and 46.1% water.

[0025] The process exhaust gas after secondary condensation enters the tertiary condenser (15m). 3 Single-channel graphite condenser), via a chilled water vertical circulation pump (5m³). 3 The system controls the return flow of chilled water (-14℃) to keep the chilled water temperature stable at -5℃. The condensate contains 87.3% dichloroethane and 7.3% water.

[0026] After three stages of condensation, the process tail gas enters the cryogenic tower (height: 5.4 meters, width: 0.4 meters, material: stainless steel) from the bottom side stream and exits from the top side stream. The cryogenic tower temperature is controlled by liquid nitrogen (-60℃) entering the purifier at the top, which stabilizes the temperature at -30℃. The vaporized liquid nitrogen gas is used in the workshop. The condensate in the cryogenic tower contains 98.3% dichloroethane and 0.1% water.

[0027] The cryogenic tower 1 includes a main cylinder 5, which is divided into an air-cooled section 6 and a liquid-cooled section 7. The liquid-cooled section 7 is located below the air-cooled section 6 and contains coolant. An air-cooled baffle 9 is installed inside the air-cooled section 6, dividing it into an air-cooled chamber 10 and an air-cooled chamber 2 11. The bottom of the baffle 9 is flush with the surface of the coolant. The air-cooled chamber 10 contains three left heat exchange tubes 12. A condenser inlet pipe 2 13 is connected to the top of each of the three left heat exchange tubes 12, and a condenser outlet pipe 2 is connected to the bottom of each of the three left heat exchange tubes 12. The condenser outlet pipe 2 is located in the liquid-cooled section 7. The air-cooled chamber 2 11 contains three right heat exchange tubes 14. A condenser inlet pipe 3 15 is connected to the top of each of the three right heat exchange tubes 14, and a condenser outlet pipe 3 is connected to the bottom of each of the three right heat exchange tubes 14. The condenser outlet pipe 3 is located in the liquid-cooled section 7. To enhance the heat exchange efficiency of the left heat exchange tube 12 and the right heat exchange tube 14, both are spiral tubes. The condenser outlet pipe 17 and the condenser inlet pipe 2 13 are connected to the bottom and top side lines of the purifier 3, respectively, while the liquid nitrogen source 4 and the condenser inlet pipe 3 15 are connected to the top and bottom of the purifier 3, respectively. For temperature control, a thermal temperature controller 2 is installed at the connection point between the purifier 3 and the condenser inlet pipe 2 13, and at the connection point between the purifier 3 and the condenser inlet pipe 3 15.

[0028] A condenser inlet pipe 16 is provided on the lower side wall of air-cooled chamber 10, and a condenser outlet pipe 17 is provided on the upper side wall of air-cooled chamber 11. Process tail gas is introduced through the condenser inlet pipe 16. After the gas pressure in air-cooled chamber 10 reaches a certain value, the process tail gas escapes from air-cooled chamber 10 through the coolant to air-cooled chamber 11. During this process, the process tail gas is pre-cooled by the coolant. After entering air-cooled chamber 11, it is further pre-cooled by three right heat exchange pipes 14 inside air-cooled chamber 11. After being pre-cooled by cryogenic tower 1, the process tail gas is discharged to purifier 3 through condenser outlet pipe 17. Purifier 3 purifies the process tail gas. During this process, liquid nitrogen source 4 connected to purifier 3 outputs liquid nitrogen to purifier 3. The liquid nitrogen is used to further reduce the temperature of the process tail gas and promote the purification reaction. Furthermore, the liquid nitrogen from the purifier 3 is transferred to the three right heat exchange tubes 14 of the cryogenic tower 1. The upper part of the right heat exchange tubes 14 is located in the second air-cooled chamber 11, and the lower part is located in the liquid-cooled section 7. The right heat exchange tubes 14 located in the second air-cooled chamber 11 can pre-cool the process exhaust gas entering the purifier 3, and the right heat exchange tubes 14 located in the liquid-cooled section 7 can reduce the temperature of the coolant. The process exhaust gas after purification by the purifier 3 has a low temperature. The temperature is increased by the thermal temperature controller 2 and the cryogenic tower 1. The low-temperature process exhaust gas enters the first air-cooled chamber 10 through the left heat exchange tube 12, where it is pre-cooled. Furthermore, the process exhaust gas in the left heat exchange tube 12 exchanges heat with the coolant in the liquid-cooled section 7. Finally, the warm purified process exhaust gas is discharged from the second condensate outlet pipe.

[0029] Liquid nitrogen (-196℃) in liquid nitrogen source 4 is drawn from purifier 3 (5m) 3 (Material: Stainless steel) The gas enters from the top and exits from the bottom into the cryogenic tower. The process exhaust gas exiting the cryogenic tower enters from the bottom side of the purifier, exits from the top side, and then enters from the top of the cryogenic tower for preheating. The preheated process exhaust gas exits from the bottom side of the cryogenic tower, at which point the dichloroethane content in the process exhaust gas has decreased to 119 mg / m³. 3 . Example 3

[0030] The process exhaust gas from the workshop (dichloroethane content 20034 mg / m³) 3 ), through 190m 3 The compressor is compressed by a screw vacuum pump at a pressure of / h, and the outlet pressure is stabilized at 0.15MPa before entering the first-stage water-cooled condenser (10m). 3 (Single-channel graphite condenser) The condensate contains 12.8% dichloroethane and 74.9% water.

[0031] The process exhaust gas after primary water cooling enters the secondary chilled water-cooled condenser (15m). 3 Single-channel graphite condenser), via a chilled water vertical circulation pump (10m³). 3The system controls the return flow of chilled water (-14℃) to keep the chilled water temperature stable at 0℃. The condensate contains 45.9% dichloroethane and 47.1% water.

[0032] The process exhaust gas after secondary condensation enters the tertiary condenser (15m). 3 Single-channel graphite condenser), via a chilled water vertical circulation pump (5m³). 3 The system controls the return flow of chilled water (-14℃) to keep the chilled water temperature stable at -5℃. The condensate contains 86.6% dichloroethane and 7.8% water.

[0033] After three-stage condensation, the process tail gas enters the cryogenic tower (height: 5.4 meters, width: 0.4 meters, material: stainless steel) from the bottom side stream and exits from the top side stream. The cryogenic tower temperature is controlled by liquid nitrogen (-60℃) entering the purifier at the top, which stabilizes the temperature at -30℃. The vaporized liquid nitrogen gas is used in the workshop. The condensate in the cryogenic tower contains 98.5% dichloroethane and 0.1% water.

[0034] The cryogenic tower 1 includes a main cylinder 5, which is divided into an air-cooled section 6 and a liquid-cooled section 7. The liquid-cooled section 7 is located below the air-cooled section 6 and contains coolant. An air-cooled baffle 9 is installed inside the air-cooled section 6, dividing it into an air-cooled chamber 10 and an air-cooled chamber 2 11. The bottom of the baffle 9 is flush with the surface of the coolant. The air-cooled chamber 10 contains three left heat exchange tubes 12. A condenser inlet pipe 2 13 is connected to the top of each of the three left heat exchange tubes 12, and a condenser outlet pipe 2 is connected to the bottom of each of the three left heat exchange tubes 12. The condenser outlet pipe 2 is located in the liquid-cooled section 7. The air-cooled chamber 2 11 contains three right heat exchange tubes 14. A condenser inlet pipe 3 15 is connected to the top of each of the three right heat exchange tubes 14, and a condenser outlet pipe 3 is connected to the bottom of each of the three right heat exchange tubes 14. The condenser outlet pipe 3 is located in the liquid-cooled section 7. To enhance the heat exchange efficiency of the left heat exchange tube 12 and the right heat exchange tube 14, both are spiral tubes. The condenser outlet pipe 17 and the condenser inlet pipe 2 13 are connected to the bottom and top side lines of the purifier 3, respectively, while the liquid nitrogen source 4 and the condenser inlet pipe 3 15 are connected to the top and bottom of the purifier 3, respectively. For temperature control, a thermal temperature controller 2 is installed at the connection point between the purifier 3 and the condenser inlet pipe 2 13, and at the connection point between the purifier 3 and the condenser inlet pipe 3 15.

[0035] A condenser inlet pipe 16 is provided on the lower side wall of air-cooled chamber 10, and a condenser outlet pipe 17 is provided on the upper side wall of air-cooled chamber 11. Process tail gas is introduced through the condenser inlet pipe 16. After the gas pressure in air-cooled chamber 10 reaches a certain value, the process tail gas escapes from air-cooled chamber 10 through the coolant to air-cooled chamber 11. During this process, the process tail gas is pre-cooled by the coolant. After entering air-cooled chamber 11, it is further pre-cooled by three right heat exchange pipes 14 inside air-cooled chamber 11. After being pre-cooled by cryogenic tower 1, the process tail gas is discharged to purifier 3 through condenser outlet pipe 17. Purifier 3 purifies the process tail gas. During this process, liquid nitrogen source 4 connected to purifier 3 outputs liquid nitrogen to purifier 3. The liquid nitrogen is used to further reduce the temperature of the process tail gas and promote the purification reaction. Furthermore, the liquid nitrogen from the purifier 3 is transferred to the three right heat exchange tubes 14 of the cryogenic tower 1. The upper part of the right heat exchange tubes 14 is located in the second air-cooled chamber 11, and the lower part is located in the liquid-cooled section 7. The right heat exchange tubes 14 located in the second air-cooled chamber 11 can pre-cool the process exhaust gas entering the purifier 3, and the right heat exchange tubes 14 located in the liquid-cooled section 7 can reduce the temperature of the coolant. The process exhaust gas after purification by the purifier 3 has a low temperature. The temperature is increased by the thermal temperature controller 2 and the cryogenic tower 1. The low-temperature process exhaust gas enters the first air-cooled chamber 10 through the left heat exchange tube 12, where it is pre-cooled. Furthermore, the process exhaust gas in the left heat exchange tube 12 exchanges heat with the coolant in the liquid-cooled section 7. Finally, the warm purified process exhaust gas is discharged from the second condensate outlet pipe.

[0036] Liquid nitrogen (-196℃) in liquid nitrogen source 4 is drawn from purifier 3 (5m) 3 (Material: Stainless steel) The gas enters from the top and exits from the bottom into the cryogenic tower. The process exhaust gas exiting the cryogenic tower enters from the bottom side of the purifier, exits from the top side, and then enters from the top of the cryogenic tower for preheating. The preheated process exhaust gas exits from the bottom side of the cryogenic tower, at which point the dichloroethane content in the process exhaust gas has decreased to 121 mg / m³. 3 .

[0037] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for separating and processing a mixture of acidic dichloroethane, characterized in that, Includes the following steps: (1) Primary water cooling: the initial process tail gas is compressed by a screw vacuum pump at 170 m 3 / h~190 m 3 / h, the outlet pressure is stabilized at 0.05 MPa~0.15 MPa, and is further introduced into a primary water cooling condenser, which is a 10 m 3 single-channel graphite condenser; (2) Secondary water cooling: The process exhaust gas after primary water cooling enters the secondary water-cooled condenser, which is 15m². 3 A single-channel graphite condenser controls the chilled water temperature to remain stable at 0°C. (3) Three-stage water cooling: The process exhaust gas after the two-stage water cooling is introduced into a three-stage water-cooled condenser, which is 15m³. 3 A single-channel graphite condenser controls the chilled water temperature to remain stable at -5°C. (4) Deep cooling: The process tail gas after three-stage water cooling is introduced into the deep cooling tower from the bottom and further discharged from the top of the deep cooling tower. The temperature of the deep cooling tower is -30℃. (5) Purification: The process tail gas after cryogenic treatment is passed into a purifier for purification; the cryogenic tower includes a main cylinder, which is divided into an air-cooled section and a liquid-cooled section. The liquid-cooled section is located below the air-cooled section and is equipped with coolant. The air-cooled section is equipped with an air-cooled baffle; the air-cooled section is divided into an air-cooled chamber one and an air-cooled chamber two by the air-cooled baffle; the lower part of the side wall of the air-cooled chamber one is equipped with a condenser inlet pipe one, and the upper part of the side wall of the air-cooled chamber two is equipped with a condenser outlet pipe one; the interior of the air-cooled chamber one is equipped with several left heat exchange tubes, and the tops of the several left heat exchange tubes are connected together. A condenser inlet pipe 2 is connected to the air-cooled chamber 2. The bottoms of the plurality of left heat exchange pipes are connected to a condenser outlet pipe 2, which is located at the liquid cooling section. The air-cooled chamber 2 is equipped with a plurality of right heat exchange pipes. The tops of the plurality of right heat exchange pipes are connected to a condenser inlet pipe 3, and the bottoms of the plurality of right heat exchange pipes are connected to a condenser outlet pipe 3, which is located at the liquid cooling section. The condenser outlet pipe 1 and the condenser inlet pipe 2 are respectively connected to the bottom side line and the top side line of the purifier. The liquid nitrogen source and the condenser inlet pipe 3 are respectively connected to the top and bottom of the purifier. A thermal temperature controller is provided at the connection passage between the purifier and the second condenser air inlet pipe, and a thermal temperature controller is provided at the connection passage between the purifier and the third condenser air inlet pipe. The coolant level is flush with the bottom of the air-cooled baffle. The process exhaust gas is introduced into the cryogenic tower for pre-cooling through the condenser inlet pipe 1, then discharged through the condenser outlet pipe 1, and enters from the bottom side line of the purifier. The purifier purifies the process exhaust gas, and the purified process exhaust gas exits from the top side line of the purifier. After exiting, the gas enters the left heat exchange pipe through the condenser inlet pipe 2 to pre-cool the process exhaust gas in the air-cooled chamber 1. During this process, liquid nitrogen from the liquid nitrogen source enters from the top of the purifier, exits from the bottom, and is transferred to the right heat exchange pipe of the cryogenic tower through the condenser inlet pipe 3 to pre-cool the process exhaust gas.

2. The method for separating and processing an acidic dichloroethane mixture according to claim 1, characterized in that: Both the left and right heat exchange tubes are spiral tubes.

3. The method for separating and processing an acidic dichloroethane mixture according to claim 1, characterized in that: The first air-cooled chamber is equipped with three left heat exchange tubes, and the second air-cooled chamber is equipped with three right heat exchange tubes.

4. The method for separating and processing an acidic dichloroethane mixture according to claim 1, characterized in that: In step (2), a 10m vertical circulating pump for chilled water is used. 3 The flow rate is controlled by adjusting the flow rate and the return flow rate of chilled water at -14℃ to stabilize the chilled water temperature at 0℃.

5. The method for separating and processing an acidic dichloroethane mixture according to claim 1, characterized in that: In step (3), a 5m vertical circulating pump for chilled water is used. 3 The flow rate is controlled by adjusting the flow rate and the return flow rate of chilled water at -14℃ to stabilize the chilled water temperature at -5℃.

6. The method for separating and processing an acidic dichloroethane mixture according to claim 1, characterized in that: Step (4): The temperature of the cryogenic tower is stabilized at -30℃ by using liquid nitrogen at -60℃.

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