A process for the synthesis of polyethylene polyamines

Abstract

The application provides a synthesis process of polyethylene polyamine and belongs to the technical field of polyethylene polyamine.The synthesis process comprises a reaction unit, a circulation unit, a deamination unit and a refining unit; fresh EDA, circulating EDA and circulating DETA are mixed in the reaction unit, the temperature is increased from 60-65 DEG C to 76-80 DEG C, and heating is carried out to 155-165 DEG C to enter a reactor; when entering the reactor, the flow rate of EDA is 8487-9381 kg / h, the flow rate of DETA is 2829-3127 kg / h, hydrogen is heated to 155-165 DEG C to enter the reactor, the flow rate of hydrogen is 220-260 kg / h, an amination reaction is carried out, the reaction temperature is 155-165 DEG C, the reaction pressure is 17.5-18.5 MPa, and the reactor is provided with a catalyst; by using the synthesis process, the raw material cost is reduced, ethylenediamine and diethylenetriamine are recycled, the purity of polyethylene polyamine is improved, and the production level of fresh ethylenediamine and fresh diethylenetriamine is reached.

Description

Technical Field

[0001] This invention belongs to the technical field of polyethylene polyamines, and specifically relates to a synthesis process for polyethylene polyamines. Background Technology

[0002] Polyethylene polyamines are a class of important fine chemical intermediates with high economic added value and high profits among ethylene amines. They are a class of aliphatic polyamine compounds whose molecular structures contain multiple amino and imino groups. Their core molecular structure uses vinyl groups as connecting units to form linear, branched, and cyclic organic amine systems. They mainly include ethylenediamine (EDA), diethylenetriamine (DETA), triethylenetetramine (TETA), tetraethylenepentamine (TEPA), and their cyclic byproducts, such as piperazine and aminoethylpiperazine.

[0003] Different types of ethylene amine products are primarily used in different consumer sectors: ethylenediamine is mainly used as an epoxy resin curing agent and in pesticide production; diethylenetriamine is mostly used as a chelating agent, surfactant, and wet strength agent in papermaking; while triethylenetetramine and higher molecular weight polyethylene polyamines are commonly used as lubricant additives and polyamide monomers; piperazine, with its unique cyclic amine structure and reactivity, has wide applications in the pharmaceutical intermediate field, and can also be used as a water treatment corrosion inhibitor to form a stable protective film on metal surfaces; aminoethylpiperazine, with both amino and cyclic structures, can regulate the curing speed and improve the adhesion and chemical resistance of coatings as an epoxy resin curing agent, playing an important role in the textile, daily chemical, and pharmaceutical fields.

[0004] In recent years, my country's ethylenediamine market has been in a transitional period from ethylenediamine to polyethylene polyamine products. However, the polyethylene polyamine market has prominent problems such as large gaps, technological deficiencies, and high dependence on foreign products. Moreover, the supply and demand ratio is imbalanced, and it is heavily reliant on imports. Therefore, it is essential to develop a synthesis process for polyethylene polyamines.

[0005] Currently, foreign companies still use the dichloroethane process to produce polyethylene polyamines. Specifically, dichloroethane and ammonia are used as raw materials, and a substitution reaction occurs under high temperature and high pressure. The chlorine atoms in dichloroethane are replaced by amino groups, and an intermolecular condensation reaction occurs to form polyamine chains, generating a mixture of polyethylene polyamines and ammonium chloride as a byproduct. However, dichloroethane is highly corrosive, requiring extremely high-quality equipment materials, which greatly increases the investment cost of the equipment. Furthermore, the yield of the byproduct ammonium chloride is relatively large, resulting in high costs for subsequent separation and purification, and easily causing environmental pollution. In addition, the selectivity of the final target products is low, with low yields of core products such as ethylenediamine, diethylenetriamine, and triethylenetetramine.

[0006] Existing technologies also employ the ethanolamine method, which uses ethanolamine and liquid ammonia as raw materials to obtain polyethylene polyamines under the catalytic action of hydrogen and metal catalysts such as nickel and cobalt. This process is green and clean, with low environmental pollution, avoids the introduction of halogens, and has high atom utilization. However, this method has high energy consumption, low yield of diethylenetriamine, and even lower yield of higher molecular weight polyethylene polyamines, which cannot meet market demand.

[0007] After long-term research and exploration, technicians have optimized and upgraded the existing ethylene amine process and proposed a new process to produce high-amine chemicals, mainly triethylenetetramine, by using ethylenediamine as raw material for hydroammoniation. This has improved the market competitiveness of the ethylene amine process. However, the existing production process still has the problem of high production costs and is not suitable for industrial production. Through further research and development by technical personnel, the low molecular weight amines (ethylenediamine and diethylenetriamine) obtained by the self-condensation of ethylenediamine were recycled and used as raw materials to participate in the reaction again. However, due to the poor controllability of the reaction, the purity of the recycled low molecular weight amines was low and unstable, making it difficult to control the reaction process. Furthermore, the reaction temperature, pressure, and material ratio of the existing technology lacked optimization, resulting in either incomplete reaction with a high recovery rate of unreacted raw materials or over-reaction, generating a large amount of high-boiling-point impurities, which increased the difficulty of separation and purification, ultimately leading to poor quality of the polyethylenepolyamine product. It is evident that while existing methods for recycling ethylenediamine and diethylenetriamine can reduce raw material costs to some extent, the resulting products are of poor quality and low purity, failing to meet current market demands. Summary of the Invention

[0008] To address the technical problems of existing technologies, this invention provides a synthesis process for polyethylene polyamines that reuses ethylenediamine and diethylenetriamine. This reduces raw material costs while improving the purity of polyethylene polyamines by optimizing process parameters such as reaction temperature and pressure, as well as material ratios, achieving production levels comparable to those using fresh ethylenediamine and fresh diethylenetriamine.

[0009] To address the aforementioned technical problems, the present invention adopts the following technical solution: A process for synthesizing polyethylene polyamines includes a reaction unit, a recycling unit, a deamination unit, and a purification unit, specifically including the following: 1. Reaction Unit Fresh EDA and recycled EDA are pressurized at 14.2-18.2 MPa by high-pressure pump P301, and then combined with recycled DETA after being pressurized at 14.2-18.2 MPa by high-pressure pump P302. The mixture is then fed into the feed heat exchanger at 60-65℃ and 11316-12508 kg / h, where it is heated to 76-80℃. It then enters the feed heater and is heated to 155-165℃. Finally, it enters the reactor from the top of the first-stage distributor. Upon entering the reactor, the EDA... The flow rate is 8487-9381 kg / h, the DETA flow rate is 2829-3127 kg / h, and hydrogen from the compressor enters the feed heater, raising the temperature to 155-165℃. Hydrogen then enters the reactor from the top at a flow rate of 220-260 kg / h for the amination reaction. The reaction temperature is 155-165℃, and the reaction pressure is 17.5-18.5 MPa. The reactor is loaded with a catalyst at a loading rate of 18.5-19.0 m³. 3 ; The fresh EDA is a colorless liquid with a purity of 99.5-99.7%, a water content of 0.25-0.50%, and a color (Pt-Co color number) of 10-20. The circulating EDA is a colorless liquid with a purity of 99.0-99.5%, a water content of 0.25-0.50%, and a color (Pt-Co color number) of 10-20; The flow rate of the fresh EDA is 3597-3975 kg / h, and the temperature is 38-42℃; The flow rate of the circulating EDA is 4890-5406 kg / h, and the temperature is 38-42℃; The cyclic DETA is a colorless liquid with a purity of 99.5-99.7%, a water content of 0.2-0.4%, and a color (Pt-Co color number) of 10-15; The temperature of the cyclic DETA is 40-50℃; The catalyst is a high-strength amine catalyst, purchased from the Dalian Institute of Chemical Physics, Chinese Academy of Sciences, model number PEA-DICP-0805.

[0010] 2. Loop Unit After the reaction is complete, the gaseous products are discharged from below the reactor packing layer. After heat exchange to 75-80℃, they are cooled to 37-42℃ and enter the V322 hot high-pressure separator. The liquid phase is depressurized to 1.8-2.0 MPa and enters the V304 cold low-pressure separator at a flow rate of 325-359 kg / h. The gas phase is depressurized to 8.8-9.0 MPa and cooled to -10 to -5℃ before entering the V323 cold high-pressure separator. The separated liquid phase enters the V305 gas-liquid separator at a flow rate of 82-90 kg / h. The separated gas phase is heated to 38-42℃ and enters the C302 high-pressure circulating gas compressor, where it is heated to 140-150℃ and pressure increased to 17.5-18.3MPa. It mixes with the gas from the C301 low-pressure circulating gas compressor and enters the E302 circulating gas heater, where it is further heated to 155-165℃ and pressure controlled at 17.5-18.0MPa. The circulating hydrogen then enters the reactor at a flow rate of 220-260kg / h. After the reaction is complete, the liquid product is discharged from the bottom of the reactor, depressurized to 1.8-2.2 MPa, and fed into the V303 hot low-pressure separator at a flow rate of 11200-12378 kg / h. The temperature of the hot low-pressure separator is 145-155℃. The separated liquid phase is fed into the T301 deammoniation tower at a flow rate of 9863-10901 kg / h at a temperature of 141-150℃. The separated gas phase is cooled to 57-62℃ and then fed into the V304 cold low-pressure separator, where it is mixed with the liquid phase separated from the V322 tank. The mixture is then cooled to 44-53℃ for separation. The separated liquid phase is fed into the T301 deammoniation tower at a flow rate of 851-941 kg / h. The separated gas phase is then deeply cooled. The gas is cooled to -10 to -5°C and enters the V305 gas-liquid separator at a flow rate of 809-895 kg / h. It mixes with the liquid phase separated from the V323 cold high-pressure separator. The temperature of the gas-liquid separator is -10 to -5°C. The separated liquid phase goes to the V102 liquid ammonia tank. The separated gas phase is used as circulating hydrogen and mixed with fresh hydrogen at a flow rate of 0.8-1.2 kg / h. The temperature of the fresh hydrogen is raised to 38-42°C and enters the C301 low-pressure circulating gas compressor at a flow rate of 293-323 kg / h. The pressure is raised to 17.5-18.3 MPa and the temperature is raised to 140-150°C. The gas is then mixed with the gas from the C302 high-pressure circulating gas compressor and enters the E302 circulating gas heater.

[0011] 3. Deamination Unit The mixture from the V303 hot low-pressure separator and the V304 cold low-pressure separator enters the T301 ammonia removal tower at a flow rate of 10714-11842 kg / h. The feed temperature is 130-140℃. The ammonia removal tower is a positive pressure tower with a pressure of 0.27-0.32 MPa. The top temperature of the tower is 94.0-103.5℃, and the bottom temperature is 168.7-178.2℃. The gas phase at the top of the tower is ammonia. After being condensed to -0.12 to -0.08℃ by the top condenser, part of it is refluxed back to the T301 ammonia removal tower, and the other part is fed into T102 as raw material. The liquid phase mixture at the bottom of the tower goes to the product refining unit. The reflux ratio is defined as: reflux flow rate to T301 deammoniation tower : flow rate of the top gas phase entering the top condenser = 1:1.45-1.53.

[0012] 4. Product Refining Unit (1) Remove EDA and PIP tower The mixture from the bottom of the T301 ammonia removal tower enters the T302 EDA and PIP removal tower. The top temperature of the tower is 82-90℃ and the bottom temperature is 176.8-186.0℃. The vapor phase from the top of the tower enters the top condenser and is condensed to 80-85℃. Part of it is refluxed back to the T302 EDA and PIP removal tower, and the other part of the mixture enters the T303 EDA tower. The liquid phase mixture from the bottom of the tower enters the T305 DETA tower. The reflux ratio is defined as: reflux flow rate to the T302 EDA and PIP removal tower : reflux flow rate from the top gas phase into the top condenser = 1:1.85-1.9. (2) EDA tower The mixture from the T303 EDA and PIP towers enters the T303 EDA tower, where the top temperature is 117-124℃ and the bottom temperature is 144.0-153.5℃. Qualified EDA is collected from the top vapor phase and cooled to 38-40℃ to be recycled to the feed tank. The side stream product enters the top condenser and is condensed to 85-95℃ before being refluxed back into the T303 EDA tower. The liquid mixture from the bottom of the tower enters the T304 PIP tower. The reflux ratio is defined as: reflux flow rate to T303 EDA tower / side-stream product flow rate to the top condenser for condensation = 1:1. (3) PIP tower The liquid phase mixture from the bottom of the EDA tower enters the T304 PIP tower. The top temperature of the tower is 154.0-163.0℃, and the bottom temperature is 152.4-203.0℃. The qualified PIP is collected from the top of the tower and cooled to 78-80℃ before being sent to the product tank area. The side stream product enters the top condenser and is condensed to 155.5-164.0℃ before being refluxed into the T304 PIP tower. The liquid phase mixture from the bottom of the tower enters the piperazine non-conforming tank. The reflux ratio is defined as: reflux flow rate to the T304 PIP tower / side-stream product flow rate to the top condenser for condensation = 1:1. (4) DETA Tower The liquid mixture from the bottom of column T302 enters column T305, a vacuum column with a pressure of -97 to -100 kPa, a top temperature of 101.0-110.5℃, and a bottom temperature of 168.5-177.5℃. The vapor phase at the top of the column is qualified DETA, which is cooled to 48-50℃ and sent to the product intermediate tank as recycled DETA. The side stream product enters the top condenser and is condensed to 85-95℃ before being refluxed back into column T305. The liquid mixture from the bottom of the column enters column T306, an AEP column. The reflux ratio is defined as: reflux flow rate to T305 DETA tower / side-stream product flow rate to the top condenser for condensation = 1:1. (5) AEP tower The liquid mixture from the bottom of the T305 DETA column enters the T306 AEP column, which is a vacuum column with a pressure of -97 kPa, a top temperature of 110.2-120.0℃, and a bottom temperature of 181.5-190.4℃. The vapor phase at the top of the column is qualified AEP and is cooled to 48-50℃ before being sent to the intermediate product tank. The side stream product enters the top condenser and is condensed to 85-95℃ before being refluxed back into the T306 AEP column. The liquid mixture from the bottom of the column enters the T307 TETA column. The reflux ratio is defined as: reflux flow rate to T306 AEP tower / side-stream product flow rate to the top condenser for condensation = 1:1. (6) TETA Tower The liquid mixture from the bottom of the T306 AEP column enters the T307 TETA column, which is a vacuum column with a pressure of -98 to -102 kPa, a top temperature of 136.4-145.3℃, and a bottom temperature of 217.2-226.5℃. The vapor phase at the top of the column is TETA, which is cooled to 77-80℃ and sent to the intermediate product tank. The side stream product enters the top condenser and is condensed to 85-95℃ before being refluxed into the T307 TETA column. The liquid mixture at the bottom of the column goes to the heavy amine storage tank. The reflux ratio is defined as: reflux flow rate to the T307 TETA tower / side-stream product flow rate to the top condenser for condensation = 1:1.

[0013] Compared with the prior art, the present invention has achieved the following beneficial effects: 1. Using the production process of this invention, every 3597-3975 kg of ethylenediamine (EDA) can produce 274.2-303 kg of diethylenetriamine (DETA), 1234.3-1364 kg of piperazine (PIP), 178.3-197 kg of aminoethylpiperazine (AEP), 850-939.6 kg of triethylenetetramine (TETA), 205.6-227.3 kg of heavy amine, and 852.1-941.6 kg of ammonia; 2. The recycled EDA obtained using the synthesis process of this invention is a colorless liquid with a purity of 99.0-99.5%, a water content of 0.25-0.5%, and a color (Pt-Co color number) of 10-20; The recycled DETA obtained using the synthesis process of this invention is a colorless liquid with a purity of 99.5-99.8%, a water content of 0.2-0.4%, and a color (Pt-Co color number) of 10-15. The PIP product obtained using the synthesis process of this invention has a purity of 99.80-99.85%, a hydroxyethyl ethylenediamine content of 0, and a color (Pt-Co color number) of 10-15. The AEP product obtained using the synthesis process of this invention has a color (Pt-Co color number) of 30-40, a purity of 98.2-98.3%, a water content of 0.4-0.5 wt%, and a refractive index n. 20 / D is 1.4950-1.5010; The TETA product obtained using the synthesis process of this invention has a color (Pt-Co color number) of 10-20, a purity of 99.5-99.7%, and a water content of 0.3-0.5 wt%. 3. Using the synthesis process of the present invention, the TEPA content in the obtained heavy amine product is 88.6-94.7 wt%. Detailed Implementation

[0014] To provide a clearer understanding of the technical features, objectives, and effects of the present invention, specific embodiments of the present invention are now described.

[0015] Example 1 1. Reaction Unit Fresh EDA and recycled EDA are pressurized to 16.7 MPa by high-pressure pump P301, then combined with recycled DETA pressurized to 16.7 MPa by high-pressure pump P302. The combined mixture is then fed into the feed heat exchanger at 65°C and 12508 kg / h, where it is heated to 80°C. It then enters the feed heater and is heated to 165°C. The EDA flow rate is 9381 kg / h, and the DETA flow rate is 3127 kg / h. Hydrogen from the compressor enters the feed heater, where its temperature is raised to 165°C. Hydrogen then enters the reactor from the top at a flow rate of 260 kg / h for the amination reaction. The reaction temperature is 165°C, and the reaction pressure is 18.0 MPa. The reactor contains a catalyst with a loading of 19.0 m³. 3 ; The fresh EDA is a colorless liquid with a purity of 99.7%, a water content of 0.43%, and a color (Pt-Co color number) of 15. The circulating EDA is a colorless liquid with a purity of 99.3%, a water content of 0.40%, and a color (Pt-Co color number) of 15. The flow rate of the fresh EDA is 3975 kg / h, and the temperature is 42°C; The flow rate of the circulating EDA is 5406 kg / h, and the temperature is 42℃; The cyclic DETA is a colorless liquid with a purity of 99.7%, a water content of 0.3%, and a color (Pt-Co color number) of 12. The temperature of the cyclic DETA is 50°C; The catalyst is a high-strength amine catalyst, purchased from the Dalian Institute of Chemical Physics, Chinese Academy of Sciences, model number PEA-DICP-0805.

[0016] 2. Loop Unit After the reaction is complete, the gaseous products are discharged from below the reactor packing layer. After heat exchange to 80°C, they are cooled to 42°C and enter the V322 hot high-pressure separator. The liquid phase is depressurized to 2.0 MPa and enters the V304 cold low-pressure separator at a flow rate of 359 kg / h. The gas phase is depressurized to 9.0 MPa and cooled to -10°C and enters the V323 cold high-pressure separator. The separated liquid phase enters the V305 gas-liquid separator at a flow rate of 90 kg / h. The separated gas phase is heated to 42°C and enters the C302 high-pressure circulating gas compressor. The temperature is increased to 150°C and the pressure is increased to 18.0 MPa. It mixes with the gas from the C301 low-pressure circulating gas compressor and enters the E302 circulating gas heater. The temperature is further increased to 165°C and the pressure is controlled at 18.0 MPa. The circulating hydrogen enters the reactor as circulating hydrogen at a flow rate of 260 kg / h. After the reaction, the liquid product is discharged from the bottom of the reactor, depressurized to 2.2 MPa, and fed into the V303 hot low-pressure separator at a flow rate of 12378 kg / h. The temperature of the hot low-pressure separator is 155℃. The separated liquid phase is fed into the T301 deammoniation tower at a flow rate of 10901 kg / h at a temperature of 150℃. The separated gas phase is cooled to 62℃ and then fed into the V304 cold low-pressure separator, where it is mixed with the liquid phase separated from the V322 tank. The mixture is then cooled to 53℃ for separation. The separated liquid phase is fed into the T301 deammoniation tower at a flow rate of 941 kg / h. The separated gas phase is then further cooled to... At -10℃, the gas enters the V305 gas-liquid separator at a flow rate of 895 kg / h, where it mixes with the liquid phase separated from the V323 cold high-pressure separator. The temperature of the gas-liquid separator is -10℃. The separated liquid phase goes to the V102 liquid ammonia tank, and the separated gas phase is used as circulating hydrogen and mixed with fresh hydrogen at a flow rate of 1.2 kg / h. The temperature of the fresh hydrogen is increased to 42℃, and it enters the C301 low-pressure circulating gas compressor at a flow rate of 323 kg / h. The pressure is increased to 18.0 MPa, and the temperature is increased to 150℃. It mixes with the gas from the C302 high-pressure circulating gas compressor and enters the E302 circulating gas heater.

[0017] 3. Deamination Unit The mixture from the V303 hot low-pressure separator and the V304 cold low-pressure separator enters the T301 ammonia removal tower at a flow rate of 11842 kg / h. The feed temperature is 140℃. The ammonia removal tower is a positive pressure tower with a pressure of 0.32 MPa. The top temperature of the tower is 103.5℃ and the bottom temperature is 178.2℃. The gas phase at the top of the tower is ammonia. After being condensed to -0.12℃ by the top condenser, part of it is refluxed back to the T301 ammonia removal tower, and the other part is used as raw material to enter T102. The liquid phase mixture at the bottom of the tower goes to the product refining unit. The reflux ratio is defined as: reflux flow rate to T301 deammoniation tower : reflux flow rate of the top gas phase entering the top condenser = 1:1.53.

[0018] 4. Product Refining Unit (1) Remove EDA and PIP tower The mixture from the bottom of the T301 ammonia removal tower enters the T302 EDA and PIP removal tower. The top temperature of the tower is 90℃ and the bottom temperature is 186.0℃. The vapor phase from the top of the tower enters the top condenser and is condensed to 85℃. Part of it is refluxed to the T302 EDA and PIP removal tower, and the other part of the mixture enters the T303 EDA tower. The liquid phase mixture from the bottom of the tower enters the T305 DETA tower. The reflux ratio is defined as: reflux flow rate to the T302 EDA and PIP removal tower : reflux flow rate from the top gas phase into the top condenser = 1:1.9. (2) EDA tower The mixture from the T303 EDA and PIP towers enters the T303 EDA tower, where the top temperature is 124°C and the bottom temperature is 153.5°C. The qualified EDA is collected from the top vapor phase and cooled to 40°C to be recycled to the feed tank. The side stream product enters the top condenser and is condensed to 95°C before being refluxed back to the T303 EDA tower. The liquid mixture at the bottom of the tower enters the T304 PIP tower. The reflux ratio is defined as: reflux flow rate to T303 EDA tower / side-stream product flow rate to the top condenser for condensation = 1:1. (3) PIP tower The liquid phase mixture from the bottom of the EDA tower enters the T304 PIP tower. The top temperature of the tower is 163.0℃ and the bottom temperature is 203.0℃. The qualified PIP is collected from the top gas phase and cooled to 80℃ before being sent to the product tank area. The side stream product enters the top condenser and is condensed to 164.0℃ before being refluxed back into the T304 PIP tower. The liquid phase mixture from the bottom of the tower enters the piperazine non-conforming tank. The reflux ratio is defined as: reflux flow rate to the T304 PIP tower / side-stream product flow rate to the top condenser for condensation = 1:1. (4) DETA Tower The liquid mixture from the bottom of column T302 enters column T305, a vacuum column with a pressure of -97 kPa, a top temperature of 110.5℃, and a bottom temperature of 177.5℃. The vapor phase at the top of the column is qualified DETA, which is cooled to 50℃ and sent to the product intermediate tank as recycled DETA. The side stream product enters the top condenser and is condensed to 95℃ before being refluxed back into column T305. The liquid mixture from the bottom of the column enters column T306, an AEP column. The reflux ratio is defined as: reflux flow rate to T305 DETA tower / side-stream product flow rate to the top condenser for condensation = 1:1. (5) AEP tower The liquid mixture from the bottom of the T305 DETA column enters the T306 AEP column, which is a vacuum column with a pressure of -97 kPa, a top temperature of 120.0℃, and a bottom temperature of 190.4℃. The vapor phase at the top of the column is qualified AEP and is cooled to 50℃ before being sent to the intermediate product tank. The side stream product enters the top condenser and is condensed to 95℃ before being refluxed back into the T306 AEP column. The liquid mixture from the bottom of the column enters the T307 TETA column. The reflux ratio is defined as: reflux flow rate to T306 AEP tower / side-stream product flow rate to the top condenser for condensation = 1:1. (6) TETA Tower The liquid mixture from the bottom of the T306 AEP column enters the T307 TETA column, which is a vacuum column with a pressure of -100 kPa, a top temperature of 145.3℃, and a bottom temperature of 226.5℃. The vapor phase at the top of the column is TETA, which is cooled to 80℃ and sent to the intermediate product tank. The side stream product enters the top condenser and is condensed to 95℃ before being refluxed back into the T307 TETA column. The liquid mixture from the bottom of the column goes to the heavy amine storage tank. The reflux ratio is defined as: reflux flow rate to the T307 TETA tower / side-stream product flow rate to the top condenser for condensation = 1:1.

[0019] Using the production process of Example 1, every 3975 kg of ethylenediamine (EDA) can produce 303 kg of diethylenetriamine (DETA), 1364 kg of piperazine (PIP), 197 kg of aminoethylpiperazine (AEP), 939.6 kg of triethylenetetramine (TETA), 227.3 kg of heavy amine, and 941.6 kg of ammonia.

[0020] Example 2 1. Reaction Unit Fresh EDA and recycled EDA are pressurized to 14.2 MPa by high-pressure pump P301, then combined with recycled DETA pressurized to 14.2 MPa by high-pressure pump P302. The combined mixture is fed into the feed heat exchanger at 60°C and 11316 kg / h, heated to 76°C. It then enters the feed heater and is heated to 155°C. The EDA flow rate is 8487 kg / h, and the DETA flow rate is 2829 kg / h. Hydrogen from the compressor enters the feed heater, is heated to 155°C, and then enters the reactor from the top at a flow rate of 220 kg / h for the amination reaction. The reaction temperature is 155°C, and the reaction pressure is 17.5 MPa. The reactor contains a catalyst with a loading of 18.5 m³. 3 ; The fresh EDA is a colorless liquid with a purity of 99.5%, a water content of 0.50%, and a color (Pt-Co color number) of 20. The circulating EDA is a colorless liquid with a purity of 99.0%, a water content of 0.50%, and a color (Pt-Co color number) of 20. The flow rate of the fresh EDA is 3597 kg / h, and the temperature is 38°C; The flow rate of the circulating EDA is 4890 kg / h, and the temperature is 38°C. The cyclic DETA is a colorless liquid with a purity of 99.5%, a water content of 0.4%, and a color (Pt-Co color number) of 15; The temperature of the cyclic DETA is 40°C; The catalyst is a high-strength amine catalyst, purchased from the Dalian Institute of Chemical Physics, Chinese Academy of Sciences, model number PEA-DICP-0805.

[0021] 2. Loop Unit After the reaction is complete, the gaseous products are discharged from below the reactor packing layer. After heat exchange to 75°C, they are cooled to 37°C and enter the V322 hot high-pressure separator. The liquid phase is depressurized to 1.8 MPa and enters the V304 cold low-pressure separator at a flow rate of 325 kg / h. The gas phase is depressurized to 8.8 MPa and cooled to -5°C and enters the V323 cold high-pressure separator. The separated liquid phase enters the V305 gas-liquid separator at a flow rate of 82 kg / h. The separated gas phase is heated to 38°C and enters the C302 high-pressure circulating gas compressor. The temperature is increased to 140°C and the pressure is increased to 17.5 MPa. It mixes with the gas from the C301 low-pressure circulating gas compressor and enters the E302 circulating gas heater. The temperature is further increased to 155°C and the pressure is controlled at 17.5 MPa. The circulating hydrogen enters the reactor as circulating hydrogen at a flow rate of 220 kg / h. After the reaction is complete, the liquid product is discharged from the bottom of the reactor, depressurized to 1.8 MPa, and fed into the V303 hot low-pressure separator at a flow rate of 11200 kg / h. The temperature of the hot low-pressure separator is 145℃. The separated liquid phase is fed into the T301 deammoniation tower at a flow rate of 9863 kg / h at a temperature of 141℃. The separated gas phase is cooled to 57℃ and then fed into the V304 cold low-pressure separator, where it is mixed with the liquid phase separated from the V322 tank. The mixture is then cooled to 44℃ for separation. The separated liquid phase is fed into the T301 deammoniation tower at a flow rate of 851 kg / h. The separated gas phase is then deeply cooled. The gas is heated to -5℃ and enters the V305 gas-liquid separator at a flow rate of 809 kg / h. It mixes with the liquid phase separated from the V323 cold high-pressure separator. The temperature of the gas-liquid separator is -5℃. The separated liquid phase goes to the V102 liquid ammonia tank. The separated gas phase is used as circulating hydrogen and mixed with fresh hydrogen at a flow rate of 0.8 kg / h. The temperature of the fresh hydrogen is increased to 38℃ and enters the C301 low-pressure circulating gas compressor at a flow rate of 293 kg / h. The pressure is increased to 17.5 MPa and the temperature is increased to 140℃. The gas is mixed with the gas from the C302 high-pressure circulating gas compressor and enters the E302 circulating gas heater.

[0022] 3. Deamination Unit The mixture from the V303 hot low-pressure separator and the V304 cold low-pressure separator enters the T301 ammonia removal tower at a flow rate of 10714 kg / h. The feed temperature is 130℃. The ammonia removal tower is a positive pressure tower with a pressure of 0.27 MPa. The top temperature of the tower is 94.0℃ and the bottom temperature is 168.7℃. The gas phase at the top of the tower is ammonia. After being condensed to -0.08℃ by the top condenser, part of it is refluxed back to the T301 ammonia removal tower, and the other part is fed into T102 as raw material. The liquid phase mixture at the bottom of the tower goes to the product refining unit. The reflux ratio is defined as: reflux flow rate to T301 deammoniation tower : reflux flow rate of the top gas phase entering the top condenser = 1:1.45.

[0023] 4. Product Refining Unit (1) Remove EDA and PIP tower The mixture from the bottom of the T301 ammonia removal tower enters the T302 EDA and PIP removal tower. The top temperature of the tower is 82°C and the bottom temperature is 176.8°C. The vapor phase from the top of the tower enters the top condenser and is condensed to 80°C. Part of it is refluxed to the T302 EDA and PIP removal tower, and the other part of the mixture enters the T303 EDA tower. The liquid phase mixture from the bottom of the tower enters the T305 DETA tower. The reflux ratio is defined as: reflux flow rate to the T302 EDA and PIP removal tower : reflux flow rate of the top gas phase entering the top condenser = 1:1.85. (2) EDA tower The mixture from the T303 EDA and PIP towers enters the T303 EDA tower, where the top temperature is 117°C and the bottom temperature is 144.0°C. The qualified EDA is collected from the top vapor phase and cooled to 38°C to be recycled to the feed tank. The side stream product enters the top condenser and is condensed to 85°C before being refluxed back to the T303 EDA tower. The liquid mixture at the bottom of the tower enters the T304 PIP tower. The reflux ratio is defined as: reflux flow rate to T303 EDA tower / side-stream product flow rate to the top condenser for condensation = 1:1. (3) PIP tower The liquid phase mixture from the bottom of the EDA tower enters the T304 PIP tower. The top temperature of the tower is 154.0℃ and the bottom temperature is 152.4℃. The qualified PIP is collected from the top of the tower and cooled to 78℃ before being sent to the product tank area. The side stream product enters the top condenser and is condensed to 155.5℃ before being refluxed into the T304 PIP tower. The liquid phase mixture from the bottom of the tower enters the piperazine non-conforming tank. The reflux ratio is defined as: reflux flow rate to the T304 PIP tower / side-stream product flow rate to the top condenser for condensation = 1:1. (4) DETA Tower The liquid phase mixture from the bottom of column T302 enters column T305, which is a vacuum column with a pressure of -98 kPa, a top temperature of 101.0℃, and a bottom temperature of 168.5℃. The vapor phase at the top of the column is qualified DETA, which is cooled to 48℃ and sent to the product intermediate tank as recycled DETA. The side stream product enters the top condenser and is condensed to 85℃ before being refluxed back to column T305. The liquid phase mixture from the bottom of the column enters column T306, AEP column. The reflux ratio is defined as: reflux flow rate to T305 DETA tower / side-stream product flow rate to the top condenser for condensation = 1:1. (5) AEP tower The liquid mixture from the bottom of the T305 DETA column enters the T306 AEP column, which is a vacuum column with a pressure of -98 kPa, a top temperature of 110.2℃, and a bottom temperature of 181.5℃. The vapor phase at the top of the column is qualified AEP and is cooled to 48℃ before being sent to the intermediate product tank. The side stream product enters the top condenser and is condensed to 85℃ before being refluxed back to the T306 AEP column. The liquid mixture from the bottom of the column enters the T307 TETA column. The reflux ratio is defined as: reflux flow rate to T306 AEP tower / side-stream product flow rate to the top condenser for condensation = 1:1. (6) TETA Tower The liquid mixture from the bottom of the T306 AEP column enters the T307 TETA column, which is a vacuum column with a pressure of -98 kPa, a top temperature of 136.4℃, and a bottom temperature of 217.2℃. The vapor phase at the top of the column is TETA, which is cooled to 77℃ and sent to the intermediate product tank. The side stream product enters the top condenser and is condensed to 85℃ before being refluxed back into the T307 TETA column. The liquid mixture from the bottom of the column goes to the heavy amine storage tank. The reflux ratio is defined as: reflux flow rate to the T307 TETA tower / side-stream product flow rate to the top condenser for condensation = 1:1.

[0024] Using the production process of Example 2, every 3597 kg of ethylenediamine (EDA) can produce 274.2 kg of diethylenetriamine (DETA), 1234.3 kg of piperazine (PIP), 178.3 kg of aminoethylpiperazine (AEP), 850 kg of triethylenetetramine (TETA), 205.6 kg of heavy amine, and 852.1 kg of ammonia.

[0025] Example 3 1. Reaction Unit Fresh EDA and recycled EDA are pressurized to 18.2 MPa by high-pressure pump P301, then combined with recycled DETA pressurized to 18.2 MPa by high-pressure pump P302. The combined mixture is then fed into the feed heat exchanger at 63°C and 11912 kg / h, where it is heated to 78°C. It then enters the feed heater and is heated to 160°C. The EDA flow rate is 8934 kg / h, and the DETA flow rate is 2978 kg / h. Hydrogen from the compressor enters the feed heater, where its temperature is raised to 160°C. Hydrogen then enters the reactor from the top at a flow rate of 240 kg / h for the amination reaction. The reaction temperature is 160°C, and the reaction pressure is 18.5 MPa. The reactor contains a catalyst with a loading of 18.8 m³. 3 ; The fresh EDA is a colorless liquid with a purity of 99.8%, a water content of 0.25%, and a color (Pt-Co color number) of 10. The circulating EDA is a colorless liquid with a purity of 99.5%, a water content of 0.25%, and a color (Pt-Co color number) of 10. The flow rate of the fresh EDA is 3786 kg / h, and the temperature is 40°C; The flow rate of the circulating EDA is 5148 kg / h, and the temperature is 40℃; The cyclic DETA is a colorless liquid with a purity of 99.8%, a water content of 0.2%, and a color (Pt-Co color number) of 10; The temperature of the cyclic DETA is 45°C; The catalyst is a high-strength amine catalyst, purchased from the Dalian Institute of Chemical Physics, Chinese Academy of Sciences, model number PEA-DICP-0805.

[0026] 2. Loop Unit After the reaction is complete, the gaseous products are discharged from below the reactor packing layer. After heat exchange to 78°C, they are cooled to 40°C and enter the V322 hot high-pressure separator. The liquid phase is depressurized to 2.0 MPa and enters the V304 cold low-pressure separator at a flow rate of 342 kg / h. The gas phase is depressurized to 9.0 MPa and cooled to -8°C before entering the V323 cold high-pressure separator. The separated liquid phase enters the V305 gas-liquid separator at a flow rate of 86 kg / h. The separated gas phase is heated to 40°C and enters the C302 high-pressure circulating gas compressor. The temperature is increased to 145°C and the pressure is increased to 18.3 MPa. It mixes with the gas from the C301 low-pressure circulating gas compressor and enters the E302 circulating gas heater. The temperature is further increased to 160°C and the pressure is controlled at 18.0 MPa. The circulating hydrogen enters the reactor at a flow rate of 240 kg / h. After the reaction is complete, the liquid product is discharged from the bottom of the reactor, depressurized to 2.0 MPa, and fed into the V303 hot low-pressure separator at a flow rate of 11789 kg / h. The temperature of the hot low-pressure separator is 150℃. The separated liquid phase is fed into the T301 deammoniation tower at a flow rate of 10382 kg / h at a temperature of 146℃. The separated gas phase is cooled to 60℃ and then fed into the V304 cold low-pressure separator, where it is mixed with the liquid phase separated from the V322 tank. The mixture is then cooled to 49℃ for separation. The separated liquid phase is fed into the T301 deammoniation tower at a flow rate of 896 kg / h. The separated gas phase is then deeply cooled. The gas is heated to -8℃ and enters the V305 gas-liquid separator at a flow rate of 852 kg / h. It mixes with the liquid phase separated from the V323 cold high-pressure separator. The temperature of the gas-liquid separator is -8℃. The separated liquid phase goes to the V102 liquid ammonia tank. The separated gas phase is used as circulating hydrogen and mixed with fresh hydrogen at a flow rate of 1.0 kg / h. The temperature of the fresh hydrogen is increased to 40℃ and it enters the C301 low-pressure circulating gas compressor at a flow rate of 308 kg / h. The pressure is increased to 18.3 MPa and the temperature is increased to 145℃. It mixes with the gas from the C302 high-pressure circulating gas compressor and enters the E302 circulating gas heater.

[0027] 3. Deamination Unit The mixture from the V303 hot low-pressure separator and the V304 cold low-pressure separator enters the T301 ammonia removal tower at a flow rate of 11278 kg / h. The feed temperature is 136℃. The ammonia removal tower is a positive pressure tower with a pressure of 0.30 MPa. The top temperature of the tower is 98.5℃ and the bottom temperature is 173.5℃. The gas phase at the top of the tower is ammonia. After being condensed to -0.10℃ by the top condenser, part of it is refluxed back to the T301 ammonia removal tower, and the other part is fed into T102 as raw material. The liquid phase mixture at the bottom of the tower goes to the product refining unit. The reflux ratio is defined as: reflux flow rate to T301 deammoniation tower : reflux flow rate of the top gas phase entering the top condenser = 1:1.5.

[0028] 4. Product Refining Unit (1) Remove EDA and PIP tower The mixture from the bottom of the T301 ammonia removal tower enters the T302 EDA and PIP removal tower. The top temperature of the tower is 86°C and the bottom temperature is 181.4°C. The vapor phase from the top of the tower enters the top condenser and is condensed to 82°C. Part of it is refluxed back to the T302 EDA and PIP removal tower, and the other part of the mixture enters the T303 EDA tower. The liquid phase mixture from the bottom of the tower enters the T305 DETA tower. The reflux ratio is defined as: reflux flow rate to the T302 EDA and PIP removal tower : reflux flow rate of the top gas phase entering the top condenser = 1:1.87. (2) EDA tower The mixture from the T303 EDA and PIP towers enters the T303 EDA tower, where the top temperature is 120°C and the bottom temperature is 149.1°C. The qualified EDA is collected from the top vapor phase and cooled to 40°C to be recycled to the feed tank. The side stream product enters the top condenser and is condensed to 90°C before being refluxed back to the T303 EDA tower. The liquid mixture at the bottom of the tower enters the T304 PIP tower. The reflux ratio is defined as: reflux flow rate to T303 EDA tower / side-stream product flow rate to the top condenser for condensation = 1:1. (3) PIP tower The liquid phase mixture from the bottom of the EDA tower enters the T304 PIP tower. The top temperature of the tower is 158.8℃ and the bottom temperature is 192.4℃. The qualified PIP is collected from the top of the tower and cooled to 80℃ before being sent to the product tank area. The side stream product enters the top condenser and is condensed to 159.1℃ before being refluxed back into the T304 PIP tower. The liquid phase mixture from the bottom of the tower enters the piperazine non-conforming tank. The reflux ratio is defined as: reflux flow rate to the T304 PIP tower / side-stream product flow rate to the top condenser for condensation = 1:1. (4) DETA Tower The liquid phase mixture from the bottom of column T302 enters column T305, which is a vacuum column with a pressure of -100 kPa, a top temperature of 105.6℃, and a bottom temperature of 172.9℃. The vapor phase at the top of the column is qualified DETA, which is cooled to 50℃ and sent to the product intermediate tank as recycled DETA. The side stream product enters the top condenser and is condensed to 90℃ before being refluxed back to column T305. The liquid phase mixture from the bottom of the column enters column T306, AEP column. The reflux ratio is defined as: reflux flow rate to T305 DETA tower / side-stream product flow rate to the top condenser for condensation = 1:1. (5) AEP tower The liquid mixture from the bottom of the T305 DETA column enters the T306 AEP column, which is a vacuum column with a pressure of -100 kPa, a top temperature of 114.7℃, and a bottom temperature of 186.5℃. The vapor phase at the top of the column is qualified AEP and is cooled to 50℃ before being sent to the intermediate product tank. The side stream product enters the top condenser and is condensed to 90℃ before being refluxed back into the T306 AEP column. The liquid mixture from the bottom of the column enters the T307 TETA column. The reflux ratio is defined as: reflux flow rate to T306 AEP tower / side-stream product flow rate to the top condenser for condensation = 1:1. (6) TETA Tower The liquid mixture from the bottom of the T306 AEP column enters the T307 TETA column, which is a vacuum column with a pressure of -102 kPa, a top temperature of 140.3℃, and a bottom temperature of 221.8℃. The vapor phase at the top of the column is TETA, which is cooled to 80℃ and sent to the intermediate product tank. The side stream product enters the top condenser and is condensed to 90℃ before being refluxed back into the T307 TETA column. The liquid mixture from the bottom of the column goes to the TEPA column. The reflux ratio is defined as: reflux flow rate to the T307 TETA tower / side-stream product flow rate to the top condenser for condensation = 1:1.

[0029] Using the production process of Example 3, every 3786 kg of ethylenediamine (EDA) can produce 288.7 kg of diethylenetriamine (DETA), 1299.2 kg of piperazine (PIP), 187.7 kg of aminoethylpiperazine (AEP), 895.0 kg of triethylenetetramine (TETA), 216.5 kg of heavy amine, and 896.9 kg of ammonia.

[0030] The cyclic EDA, cyclic DETA, PIP, AEP, and TETA products obtained from the synthesis processes of Examples 1-3 were subjected to performance tests, and the test results are as follows: 1. Cyclic EDA

[0031] 2. Looping DETA

[0032] 3. PIP products

[0033] 4. AEP products

[0034] 5. TETA products

[0035] 6. Heavy amine products

[0036] Unless otherwise stated, all percentages used in this invention are mass percentages.

[0037] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A process for synthesizing polyethylene polyamines, characterized in that, It includes a reaction unit, a circulation unit, a deamination unit, and a purification unit; The reaction unit combines fresh EDA, recycled EDA, and recycled DETA, heats the mixture from 60-65°C to 76-80°C, and then heats it to 155-165°C before introducing it into the reactor. The flow rate of EDA entering the reactor is 8487-9381 kg / h, and the flow rate of DETA is 2829-3127 kg / h. Hydrogen gas is heated to 155-165°C and introduced into the reactor at a flow rate of 220-260 kg / h to carry out an amination reaction. The reaction temperature is 155-165°C, and the reaction pressure is 17.5-18.5 MPa. The reactor contains a catalyst. The fresh EDA is a colorless liquid with a purity of 99.5-99.7%, a water content of 0.25-0.50%, and a color (Pt-Co color number) of 10-20. The circulating EDA is a colorless liquid with a purity of 99.0-99.5%, a water content of 0.25-0.50%, and a color (Pt-Co color number) of 10-20; the circulating DETA is a colorless liquid with a purity of 99.5-99.7%, a water content of 0.2-0.4%, and a color (Pt-Co color number) of 10-15.

2. The synthesis process of a polyethylenepolyamine according to claim 1, characterized in that, In the reaction unit, the flow rate of the fresh EDA is 3597-3975 kg / h, and the temperature is 38-42℃; The flow rate of the circulating EDA is 4890-5406 kg / h, and the temperature is 38-42℃; The temperature of the cyclic DETA is 40-50℃.

3. The synthesis process of a polyethylenepolyamine according to claim 1, characterized in that, The circulation unit includes a process where the gaseous product after the reaction is completed is discharged from below the reactor packing layer, heated to 75-80°C, cooled to 37-42°C, and enters the V322 hot high-pressure separator. The liquid phase is depressurized to 1.8-2.0 MPa and enters the V304 cold low-pressure separator at a flow rate of 325-359 kg / h. The gas phase is depressurized to 8.8-9.0 MPa and cooled to -10 to -5°C before entering the V323 cold high-pressure separator. The separated liquid phase then enters the V304 cold low-pressure separator at a flow rate of 82-90 kg / h. In the 05 gas-liquid separator, the separated gas phase is heated to 38-42℃ and enters the C302 high-pressure circulating gas compressor, where the temperature is increased to 140-150℃ and the pressure is increased to 17.5-18.3MPa. It mixes with the gas from the C301 low-pressure circulating gas compressor and enters the E302 circulating gas heater, where the temperature is further increased to 155-165℃ and the pressure is controlled at 17.5-18.0MPa. The circulating hydrogen then enters the reactor as circulating hydrogen, with a flow rate of 220-260kg / h.

4. The synthesis process of a polyethylenepolyamine according to claim 1, characterized in that, The circulation unit includes the following steps: After the reaction is completed, the liquid phase product is discharged from the bottom of the reactor, depressurized to 1.8-2.2 MPa, and enters the V303 hot low-pressure separator at a flow rate of 11200-12378 kg / h. The temperature of the hot low-pressure separator is 145-155℃. The separated liquid phase enters the T301 deammoniation tower at a flow rate of 9863-10901 kg / h at a temperature of 141-150℃. The separated gas phase is cooled to 57-62℃ and enters the V304 cold low-pressure separator, where it is mixed with the liquid phase separated from the V322 tank. After cooling to 44-53℃, the mixture is separated. The separated liquid phase enters the T301 deammoniation tower at a flow rate of 851-941 kg / h. The phase is deeply cooled to -10 to -5℃ and enters the V305 gas-liquid separator at a flow rate of 809-895 kg / h. It mixes with the liquid phase separated from the V323 cold high-pressure separator. The temperature of the gas-liquid separator is -10 to -5℃. The separated liquid phase goes to the V102 liquid ammonia tank. The separated gas phase is used as circulating hydrogen and mixed with fresh hydrogen at a flow rate of 0.8-1.2 kg / h. The temperature of the fresh hydrogen is increased to 38-42℃ and it enters the C301 low-pressure circulating gas compressor at a flow rate of 293-323 kg / h. The pressure is increased to 17.5-18.3 MPa and the temperature is increased to 140-150℃. It mixes with the gas from the C302 high-pressure circulating gas compressor and enters the E302 circulating gas heater.

5. The synthesis process of a polyethylenepolyamine according to claim 1, characterized in that, The ammonia removal unit receives a mixture from the V303 hot low-pressure separator and the V304 cold low-pressure separator. This mixture enters the T301 ammonia removal tower at a flow rate of 10714-11842 kg / h. The feed temperature is 130-140℃. The ammonia removal tower is a positive pressure tower with a pressure of 0.27-0.32 MPa. The top temperature of the tower is 94.0-103.5℃, and the bottom temperature is 168.7-178.2℃. The vapor phase at the top of the tower is ammonia. After being condensed to -0.12 to -0.08℃ by the top condenser, a portion of the vapor phase is refluxed back to the T301 ammonia removal tower, while the other portion is used as raw material and enters the T102 tower. The liquid phase mixture at the bottom of the tower is sent to the product refining unit. The reflux ratio is defined as: reflux flow rate to T301 deammoniation tower : flow rate of the top gas phase entering the top condenser = 1:1.45-1.

53.

6. The synthesis process of a polyethylenepolyamine according to claim 1, characterized in that, The product refining unit includes an EDA and PIP removal tower, an EDA tower, a PIP tower, a DETA tower, an AEP tower, and a TETA tower; The EDA and PIP removal towers are described above. The mixture from the bottom of the T301 ammonia removal tower enters the T302 EDA and PIP removal tower. The top temperature of the tower is 82-90℃, and the bottom temperature is 176.8-186.0℃. The gas phase from the top of the tower enters the top condenser and is condensed to 80-85℃. A portion of the mixture is refluxed back to the T302 EDA and PIP removal tower, and the other portion of the mixture enters the T303 EDA tower. The liquid phase mixture from the bottom of the tower enters the T305 DETA tower. The reflux ratio is defined as: reflux flow rate to the T302 EDA and PIP de-reflux column : reflux flow rate of the top gas phase entering the top condenser = 1:1.85-1.

9.

7. The synthesis process of a polyethylenepolyamine according to claim 6, characterized in that, The mixture from the T303 EDA and PIP towers enters the T303 EDA tower. The top temperature of the tower is 117-124℃, and the bottom temperature is 144.0-153.5℃. The qualified EDA is collected from the top gas phase and cooled to 38-40℃ as recycled EDA to the feed tank. The side stream product enters the top condenser and is condensed to 85-95℃ before being refluxed back into the T303 EDA tower. The liquid mixture at the bottom of the tower enters the T304 PIP tower. The reflux ratio is defined as: reflux flow rate to T303 EDA tower / side-stream product flow rate to the top condenser for condensation = 1:

1. The PIP column, from which the liquid phase mixture from the bottom of the EDA column enters the T304 PIP column, has a top temperature of 154.0-163.0℃ and a bottom temperature of 152.4-203.0℃. The qualified PIP is collected from the top vapor phase and cooled to 78-80℃ before being sent to the product tank area. The side stream product enters the top condenser and is condensed to 155.5-164.0℃ before being refluxed back into the T304 PIP column. The liquid phase mixture from the bottom of the column enters the piperazine non-conforming tank. The reflux ratio is defined as: reflux flow rate to the T304 PIP tower / side-stream product flow rate to the top condenser for condensation = 1:

1.

8. The synthesis process of a polyethylenepolyamine according to claim 7, characterized in that, The liquid phase mixture from the bottom of column T302 enters column T305, which is a vacuum column with a pressure of -97 to -100 kPa, a top temperature of 101.0-110.5℃, and a bottom temperature of 168.5-177.5℃. The vapor phase at the top of the column is qualified DETA, which is cooled to 48-50℃ and sent to the product intermediate tank as recycled DETA. The side stream product enters the top condenser and is condensed to 85-95℃ before being refluxed into column T305. The liquid phase mixture from the bottom of the column enters column T306 AEP. The reflux ratio is defined as: reflux flow rate to T305 DETA tower / side-stream product flow rate to the top condenser for condensation = 1:

1. The liquid phase mixture from the bottom of the T305 DETA column enters the T306 AEP column, which is a vacuum column with a pressure of -97 kPa, a top temperature of 110.2-120.0℃, and a bottom temperature of 181.5-190.4℃. The vapor phase at the top of the column is qualified AEP and is cooled to 48-50℃ before being sent to the intermediate product tank. The side stream product enters the top condenser and is condensed to 85-95℃ before being refluxed back into the T306 AEP column. The liquid phase mixture from the bottom of the column enters the T307 TETA column. The reflux ratio is defined as: reflux flow rate to T306 AEP tower / side-stream product flow rate to the top condenser for condensation = 1:

1.

9. The synthesis process of a polyethylenepolyamine according to claim 8, characterized in that, The liquid mixture from the bottom of the T306 AEP column enters the T307 TETA column, which is a vacuum column with a pressure of -98 to -102 kPa, a top temperature of 136.4-145.3℃, and a bottom temperature of 217.2-226.5℃. The vapor phase at the top of the column is TETA, which is cooled to 77-80℃ and sent to the intermediate product tank. The side stream product enters the top condenser and is condensed to 85-95℃ before being refluxed into the T307 TETA column. The liquid mixture at the bottom of the column goes to the heavy amine storage tank. The reflux ratio is defined as: reflux flow rate to the T307 TETA tower / side-stream product flow rate to the top condenser for condensation = 1:1.

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