A heat recovery device for the production of tetrachloroethane by chlorination of acetylene
Patent Information
- Application Number
- CN202522518640.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-27
- Publication Date
- 2026-10-30
- Estimated Expiration
- 2035-11-27
AI Technical Summary
本实用新型通过在乙炔氯化塔与全凝器之间增加第一换热器，第一换热器的冷却介质进口及冷却介质出口与液氯汽化器的加热介质出口及加热介质进口形成闭环连接，将乙炔氯化塔排出的四氯乙烷混合气余热供给液氯汽化器，对液氯进行气化，减少液氯汽化器外部热量输入，未冷凝的混合气再进入全凝器、由其冷却介质进管通入循环冷却水进行冷却，可减少全凝器循环冷却水的消耗；第一换热器及全凝器冷凝的液态粗四氯乙烷进入回流罐收集，部分液态粗四氯乙烷回流至乙炔氯化塔，维持乙炔氯化塔内四氯乙烷溶剂的恒定，另一部分通过采出调节阀进入储罐；本实用新型通过实现第一换热器的冷却系统与液氯汽化器的加热系统耦合，利用余热降低综合能耗，解决传统工艺中四氯乙烷混合气余热直接排放导致的能源浪费问题，可减少全凝器循环冷却水及液氯汽化器外部热量的输入，提升装置整体能效；
作为本实用新型的进一步改进，所述各进料调节阀、采出调节阀及调节阀均为电磁阀，各电磁阀、各温度传感器及尾部温度传感器均接入DCS系统；可实现自动控制和装置的连续稳态运行；
Smart Images
Figure CN224920976U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to a heat recovery device for the preparation of tetrachloroethane by acetylene chlorination. Background Technology
[0002] In the industrial production of trichloroethylene, the gas-phase catalytic dechlorination process via acetylene chlorination is commonly used: acetylene and chlorine undergo a chlorination addition reaction in a tetrachloroethane solvent system containing FeCl3 catalyst in an acetylene chlorination tower under suitable temperature and negative pressure conditions to produce crude tetrachloroethane. After purification, the crude tetrachloroethane is further purified by a dechlorination reaction to obtain trichloroethylene.
[0003] The existing process has the following technical bottlenecks: Energy recovery defects: The sensible heat of the tetrachloroethane mixture at the outlet of the acetylene chlorination tower at 90~110℃ is not utilized. The mixture directly enters the total condenser for cooling and liquefaction, resulting in waste of waste heat resources and high consumption of circulating cooling water. Furthermore, the liquid chlorine vaporizer used before this process relies on external low-pressure steam or high-temperature hot water for heating, resulting in high energy consumption of the unit. Summary of the Invention
[0004] The purpose of this invention is to address the shortcomings of existing technologies by providing a heat recovery device for the acetylene chlorination to tetrachloroethane production process. This device can reduce the input of external heat to the condenser circulating cooling water and liquid chlorine vaporizer, thereby improving the overall energy efficiency of the device and reducing the energy consumption of the production unit.
[0005] To achieve the above objectives, this utility model provides a heat recovery device for the preparation of tetrachloroethane from acetylene by chlorination, comprising an acetylene chlorination tower and a total condenser. The acetylene chlorination tower is equipped with two raw material gas inlet pipes, each equipped with a feed regulating valve. The device is characterized in that: the mixed gas outlet of the acetylene chlorination tower is connected to the medium inlet of a first heat exchanger; the cooling medium inlet of the first heat exchanger is connected to the heating medium outlet of a liquid chlorine vaporizer; the cooling medium outlet of the first heat exchanger is connected to the heating medium inlet of the liquid chlorine vaporizer; the total condenser is equipped with a medium inlet, a gas phase outlet pipe, a cooling medium inlet pipe, and a cooling medium outlet pipe; the gas phase outlet pipe of the first heat exchanger is connected to the medium inlet of the total condenser; the lower ends of both the first heat exchanger and the total condenser are connected to a reflux tank via condenser pipes; the lower part of the reflux tank is connected to the acetylene chlorination tower via a pipeline, which is also connected to a storage tank via a branch pipe and a withdrawal regulating valve. This invention adds a first heat exchanger between the acetylene chlorination tower and the total condenser. The cooling medium inlet and outlet of the first heat exchanger form a closed loop connection with the heating medium outlet and heating medium inlet of the liquid chlorine vaporizer. The waste heat from the tetrachloroethane mixture discharged from the acetylene chlorination tower is supplied to the liquid chlorine vaporizer to vaporize the liquid chlorine, reducing the external heat input to the liquid chlorine vaporizer. The uncondensed mixture then enters the total condenser, where it is cooled by circulating cooling water through its cooling medium inlet pipe, reducing the consumption of circulating cooling water in the total condenser. The first heat exchanger and the total condenser... The condensed crude tetrachloroethane enters the reflux tank for collection. Part of the crude tetrachloroethane is returned to the acetylene chlorination tower to maintain a constant tetrachloroethane solvent in the acetylene chlorination tower, while the other part enters the storage tank through the outlet regulating valve. This invention couples the cooling system of the first heat exchanger with the heating system of the liquid chlorine vaporizer, utilizing waste heat to reduce overall energy consumption and solve the energy waste problem caused by the direct discharge of waste heat from the tetrachloroethane mixture in traditional processes. It can also reduce the input of circulating cooling water to the total condenser and external heat to the liquid chlorine vaporizer, thereby improving the overall energy efficiency of the device. As a further improvement of this utility model, the gas phase outlet pipe of the total condenser is connected to the medium inlet of the tail cooler. The tail cooler is also provided with a gas phase outlet pipe, a cooling medium inlet pipe and a cooling medium outlet pipe. The lower end of the tail cooler is also connected to the reflux tank through a condenser pipe. The tail cooler can further cool and separate the chlorides such as tetrachloroethane carried in the tail gas. As a further improvement of this utility model, temperature sensors are provided at the bottom, middle and top of the acetylene chlorination tower; a regulating valve is provided on the cooling medium inlet pipe of the tail cooler, and a tail temperature sensor is provided on the gas phase outlet pipe of the tail cooler; the temperature of the acetylene chlorination tower can be monitored in real time to ensure the normal progress of the reaction. As a further improvement of this utility model, the first heat exchanger is a shell-and-tube heat exchanger, and the shell and tube material is graphite; it is conducive to heat exchange and has a good heat exchange effect. As a further improvement of this utility model, each of the feed regulating valve, the outlet regulating valve and the regulating valve are solenoid valves, and each solenoid valve, each temperature sensor and the tail temperature sensor are connected to the DCS system; thus, automatic control and continuous steady-state operation of the device can be realized. In summary, this invention can reduce the input of external heat to the condenser circulating cooling water and liquid chlorine vaporizer, improve the overall energy efficiency of the device, and reduce the energy consumption of the production device. Attached Figure Description
[0006] Figure 1 This is a structural diagram of an embodiment of the present utility model. Detailed Implementation
[0007] To better understand the purpose, technical solution, and beneficial effects of this utility model, the following description, in conjunction with the accompanying drawings, further illustrates this utility model, but does not limit the scope of protection of this utility model to the following embodiments.
[0008] like Figure 1 As shown, this embodiment of a heat recovery device for preparing tetrachloroethane by acetylene chlorination includes an acetylene chlorination tower 1, a first heat exchanger 2, a total condenser 3, and a tail cooler 4. The acetylene chlorination tower 1 is provided with two raw material gas inlet pipes 7 and 8, each equipped with a feed regulating valve 9. Temperature sensors 10, 11, and 12 are provided at the bottom, middle, and top of the acetylene chlorination tower 1. The first heat exchanger 2 is provided with a medium inlet, a cooling medium inlet, a cooling medium outlet, a gas phase outlet pipe, and a condenser pipe. The total condenser 3 and the tail cooler 4 are both provided with a medium inlet, a gas phase outlet pipe, a cooling medium inlet pipe, a cooling medium outlet pipe, and a condenser pipe. The mixed gas outlet of the acetylene chlorination tower 1 is connected to the medium inlet at the upper end of the first heat exchanger 2, and the cooling medium inlet of the first heat exchanger 2 is connected to the heating medium outlet of the liquid chlorine vaporizer 6. The medium outlet is connected to the heating medium inlet of the liquid chlorine vaporizer 6; the gas phase outlet pipe at the bottom of the first heat exchanger 2 is connected to the medium inlet at the top of the total condenser 3, and the gas phase outlet pipe at the bottom of the total condenser 3 is connected to the medium inlet at the top of the tail cooler 4. The cooling medium inlet pipe of the tail cooler 4 is equipped with a regulating valve 13, and the gas phase outlet pipe of the tail cooler 4 is equipped with a tail temperature sensor 14; the lower ends of the first heat exchanger 2, the total condenser 3 and the tail cooler 4 are all connected to the reflux tank 15 through their condensing pipes. The lower part of the reflux tank 15 is connected to the acetylene chlorination tower 1 through the pipeline 16. The pipeline 16 is also connected to the storage tank 18 through a branch pipe and the outlet regulating valve 17; each feed regulating valve 9, outlet regulating valve 17 and regulating valve 13 are solenoid valves, and each solenoid valve, each temperature sensor 10, 11, 12 and tail temperature sensor 13 are connected to the DCS system. The first heat exchanger 2, the total condenser 3, and the tail cooler 4 are all shell and tube heat exchangers. The shell and tube material of the first heat exchanger 2 is graphite. The liquid chlorine vaporizer 6 is equipped with a liquid chlorine inlet and a chlorine gas outlet pipe. In use, the total condenser 3 is circulated with cooling water through its cooling medium inlet pipe and cooling medium outlet pipe. The gas phase outlet pipe of the tail cooler 4 is connected to the tail gas treatment device. The tail cooler 4 is circulated with -35℃ brine through its cooling medium inlet pipe and cooling medium outlet pipe. Then, acetylene and chlorine are circulated through the two raw material gas inlets 7 and 8 to react. This invention adds a first heat exchanger 2 between the acetylene chlorination tower 1 and the total condenser 3. The cooling medium inlet and outlet of the first heat exchanger 2 form a closed loop connection with the heating medium outlet and heating medium inlet of the liquid chlorine vaporizer 6. The waste heat of the tetrachloroethane mixture discharged from the acetylene chlorination tower 1 is supplied to the liquid chlorine vaporizer 6 to vaporize the liquid chlorine inside, which reduces the external heat input to the liquid chlorine vaporizer. The uncondensed mixture then enters the total condenser 3, where it is cooled by circulating cooling water through its cooling medium inlet pipe, which reduces the consumption of circulating cooling water in the total condenser. The uncondensed mixture then enters the tail cooler 4, where it is further deeply cooled by low-temperature brine and the contents of the tail gas are separated. The tetrachloroethane and other chlorides are condensed and separated by the first heat exchanger 2, the total condenser 3 and the tail cooler 4. The liquid crude tetrachloroethane is collected in the reflux tank 15. Part of the liquid crude tetrachloroethane is returned to the acetylene chlorination tower 1 to maintain the constant tetrachloroethane solvent in the acetylene chlorination tower. The other part enters the storage tank 18 through the outlet regulating valve 17. This utility model realizes the coupling of the cooling system of the first heat exchanger 2 and the heating system of the liquid chlorine vaporizer 6, and uses waste heat to reduce the overall energy consumption. It solves the energy waste problem caused by the direct discharge of waste heat of tetrachloroethane mixed gas in the traditional process. It can reduce the input of circulating cooling water of the total condenser and external heat of the liquid chlorine vaporizer, and improve the overall energy efficiency of the device. Temperature sensors 10, 11, and 12 can monitor the temperature of acetylene chlorination tower 1 in real time, ensuring the normal progress of the reaction and full-load operation; tail temperature sensor 13 keeps the temperature of the tail gas entering the tail gas treatment device constant, which can maintain the stable operation of the tail gas treatment device; the DCS system can automatically control each feed regulating valve 9, outlet regulating valve 17, and regulating valve 13 according to relevant parameter settings, improving the automation level and operational stability of the device, and ensuring continuous steady-state operation.
Claims
1. A heat recovery device for the preparation of tetrachloroethane by acetylene chlorination, comprising an acetylene chlorination tower and a total condenser, wherein the acetylene chlorination tower is provided with two feed gas inlet pipes, each equipped with a feed regulating valve; characterized in that: The mixed gas outlet of the acetylene chlorination tower is connected to the medium inlet of the first heat exchanger. The cooling medium inlet of the first heat exchanger is connected to the heating medium outlet of the liquid chlorine vaporizer. The cooling medium outlet of the first heat exchanger is connected to the heating medium inlet of the liquid chlorine vaporizer. The total condenser is equipped with a medium inlet, a gas phase outlet pipe, a cooling medium inlet pipe, and a cooling medium outlet pipe. The gas phase outlet pipe of the first heat exchanger is connected to the medium inlet of the total condenser. The lower ends of the first heat exchanger and the total condenser are connected to the reflux tank through condenser pipes. The lower part of the reflux tank is connected to the acetylene chlorination tower through a pipeline. This pipeline is also connected to the storage tank through branch pipes and a production regulating valve.
2. The heat recovery device for the preparation of tetrachloroethane by acetylene chlorination according to claim 1, characterized in that: The vapor phase outlet pipe of the total condenser is connected to the medium inlet of the tail cooler. The tail cooler is also equipped with a vapor phase outlet pipe, a cooling medium inlet pipe and a cooling medium outlet pipe. The lower end of the tail cooler is also connected to the reflux tank through a condenser pipe.
3. The heat recovery device for the preparation of tetrachloroethane by acetylene chlorination according to claim 2, characterized in that: Temperature sensors are installed at the bottom, middle and top of the acetylene chlorination tower; a regulating valve is installed on the cooling medium inlet pipe of the tail cooler, and a tail temperature sensor is installed on the gas phase outlet pipe of the tail cooler.
4. The heat recovery device for the preparation of tetrachloroethane by acetylene chlorination according to claim 3, characterized in that: The first heat exchanger is a shell-and-tube heat exchanger, and the shell and tubes are made of graphite.
5. The heat recovery device for the preparation of tetrachloroethane by acetylene chlorination according to claim 4, characterized in that: All feed regulating valves, outlet regulating valves, and regulating valves are solenoid valves, and all solenoid valves, temperature sensors, and tail temperature sensors are connected to the DCS system.