Production device for producing dichloroethane through combination of high-temperature chlorination and low-temperature chlorination of ethylene and chlorine

Abstract

The utility model relates to the technical field of preparation of dichloroethane by chlorination, in particular to a production device for producing dichloroethane by combining high-temperature and low-temperature chlorination of ethylene and chlorine. Comprising a high-temperature chlorination reactor, a product tower, a heavy component removal tower and a light component removal tower, a first chlorine gas inlet and an ethylene gas inlet are formed in the high-temperature chlorination reactor, and a crude dichloroethane gas phase outlet is formed in the top of the high-temperature chlorination reactor; a coarse dichloroethane gas phase inlet and a product tower material outlet are formed in the tower bottom of the product tower, a product tower gas phase outlet is formed in the tower top of the product tower, and a fine dichloroethane side line extraction port and a product tower liquid phase inlet are formed in the middle of the product tower; according to the device, on the basis of reducing the consumption of steam and circulating water, reaction tail gas is utilized to react with chlorine again to generate dichloroethane, so that the output of waste gas is reduced, the conversion rate of raw materials is improved, the production cost is reduced, the production efficiency is improved, and the production cost is reduced. And the utilization rate of the raw material ethylene is increased from 77% to 95%.

Description

Technical Field

[0001] This utility model relates to the field of chlorination for the preparation of dichloroethane, specifically a production apparatus for producing dichloroethane by combining high and low temperature chlorination of ethylene with chlorine gas. Background Technology

[0002] The direct chlorination of ethylene with chlorine to produce dichloroethane is a mature process. It involves the chlorination reaction of chlorine and ethylene in a liquid dichloroethane phase under specific temperature and pressure conditions to produce 1,2-dichloroethane. Currently, the direct chlorination process for ethylene is widely used in industrial plants, mainly categorized into low-temperature chlorination, medium-temperature chlorination, and high-temperature chlorination. These methods each have advantages in terms of energy consumption, equipment, and investment costs, but also have drawbacks:

[0003] ① Low-temperature chlorination: Ethylene and chlorine react at 55℃, 0.1 MPa, in a dichloroethane solution and with a catalyst to produce dichloroethane. The advantages of low-temperature chlorination are mild reaction conditions, stable production, and low requirements for raw material purity. The disadvantages are that the heat of reaction is not utilized, additional steam is needed for distilling the dichloroethane, the produced dichloroethane requires alkaline and water washing, catalyst replenishment is necessary, and wastewater is generated.

[0004] ② Medium-temperature chlorination: Ethylene and chlorine react at 85℃, 0.015 MPa, in a dichloroethane solution with a catalyst to produce dichloroethane. The advantages of medium-temperature chlorination are that dichloroethane is discharged in the gas phase, the product purity is high, and it does not require alkali or water washing or the addition of a catalyst. The disadvantages are that the heat of reaction is not utilized, and additional steam is needed for the distillation of dichloroethane.

[0005] ③ High-temperature chlorination: Ethylene and chlorine react at 115℃, 0.1 MPa, in a dichloroethane solution with a catalyst to produce dichloroethane. The advantages of high-temperature chlorination are that dichloroethane is discharged in the gas phase, eliminating the need for alkaline or water washing, and requiring no additional catalyst; the heat of reaction is used for dichloroethane distillation. The disadvantages are that the reaction conditions are difficult to control, requiring continuous discharge of mother liquor to control the catalyst content. To control the oxygen content in the tail gas, a large excess of ethylene is required; the lack of recovery and treatment of this tail gas leads to significant waste of raw materials. Summary of the Invention

[0006] In view of the above situation and to overcome the defects of the prior art, this utility model provides a production device for producing dichloroethane by combining high and low temperature chlorination of ethylene chlorine gas, thereby reducing the energy and material consumption of ethylene chlorine gas in the production of dichloroethane.

[0007] To achieve the above objectives, this utility model provides the following technical solution: a production apparatus for producing dichloroethane by combining high and low temperature chlorination of ethylene and chlorine, comprising a high-temperature chlorination reactor, a product tower, a heavy removal tower, and a light removal tower;

[0008] The high-temperature chlorination reactor is equipped with a first chlorine gas inlet and an ethylene gas inlet, and the top of the high-temperature chlorination reactor is equipped with a crude dichloroethane gas phase outlet.

[0009] The product tower has a crude dichloroethane gas phase inlet and a product tower material outlet at the bottom, a product tower gas phase outlet at the top, and a refined dichloroethane side stream outlet and a product tower liquid phase inlet in the middle.

[0010] The deweight removal tower has a material inlet in the middle, a heavy component outlet at the bottom, and a gas phase outlet at the top.

[0011] The light-weight removal tower is provided with a liquid phase inlet and a liquid phase outlet at the bottom, and a gas phase outlet at the top.

[0012] The crude dichloroethane gas phase outlet of the high-temperature chlorination reactor is connected to the crude dichloroethane gas phase inlet of the product tower. The product tower material outlet is connected to the heavy precipitator material inlet of the heavy precipitator. The product tower gas phase outlet is connected to the light precipitator liquid phase inlet of the light precipitator. The light precipitator liquid phase outlet is connected to the product tower liquid phase inlet of the product tower.

[0013] Furthermore, it also includes a low-temperature chlorination reactor, which is equipped with a nitrogen inlet, a second chlorine inlet, a tail gas inlet, and a low-temperature reactor liquid phase outlet. The top of the high-temperature chlorination reactor is equipped with a high-temperature reactor liquid phase inlet, and the low-temperature reactor liquid phase outlet of the low-temperature chlorination reactor is connected to the high-temperature reactor liquid phase inlet of the high-temperature chlorination reactor. The product tower gas phase outlet of the product tower is connected to the tail gas inlet of the low-temperature chlorination reactor.

[0014] Furthermore, a first condenser, a reflux tank, a second condenser, a cryogenic cooler, a first buffer tank, and a neutralization tank are sequentially connected between the gas phase outlet of the product tower and the liquid phase inlet of the light phase removal tower.

[0015] Furthermore, the reflux tank is connected to the product tower, the first buffer tank is connected to the tail gas inlet of the low-temperature chlorination reactor, and the neutralization tank is equipped with a sodium hydroxide solution inlet and a wastewater outlet.

[0016] Furthermore, the gas phase outlet of the light-light removal tower is connected to a third condenser, and a second buffer tank is connected to the third condenser. The second buffer tank is provided with a second buffer tank tail gas outlet, a second buffer tank aqueous phase outlet, and a second buffer tank liquid phase outlet. The second buffer tank aqueous phase outlet is connected to a neutralization tank, and the second buffer tank liquid phase outlet is connected to the light-light removal tower.

[0017] Furthermore, a fourth condenser is connected to the gas phase outlet of the de-weighting tower, and a third buffer tank is connected to the fourth condenser. The third buffer tank is provided with a third buffer tank tail gas outlet and a third buffer tank liquid phase outlet, and the third buffer tank liquid phase outlet is connected to the de-weighting tower.

[0018] Furthermore, the bottom of the high-temperature chlorination reactor is provided with a circulating material inlet, and the product tower material outlet of the product tower is connected to the circulating material inlet;

[0019] The top of the low-temperature chlorination reactor is equipped with a fifth condenser;

[0020] A fourth buffer tank is provided between the liquid phase outlet of the low-temperature reactor and the liquid phase inlet of the high-temperature reactor.

[0021] Furthermore, the top temperature of the product tower is 90~110℃, and the pressure is 0.005MPa~0.02MPa;

[0022] The high-temperature chlorination reactor operates at a temperature of 105~125℃ and a pressure of 0.1~0.3MPa.

[0023] The top temperature of the deweight removal tower is 42-52℃, and the pressure is -0.070~-0.080MPa;

[0024] The top temperature of the light-weight removal tower is 75-85℃, and the pressure is 0.06~0.07MPa;

[0025] The temperature of the low-temperature chlorination reactor is 50~60℃.

[0026] Furthermore, the high-temperature chlorination reactor includes a U-shaped circulation section, a gas-liquid separation tank, and a spray section. The circulating material inlet, the first chlorine gas inlet, and the ethylene gas inlet are located in the U-shaped circulation section, while the high-temperature reactor liquid phase inlet and the crude dichloroethane gas phase outlet are located in the spray section. An axial flow pump is installed at the bend of the U-shaped circulation section.

[0027] Compared with the prior art, the beneficial effects of the present invention are:

[0028] This invention reduces steam and circulating water consumption by using the reaction tail gas to react with chlorine again to generate dichloroethane, thereby reducing waste gas generation and increasing the conversion rate of raw materials. The utilization rate of ethylene raw material for high-temperature chlorination is increased from 77% to 95%. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the connection structure according to an embodiment of the present utility model;

[0030] In the picture:

[0031] High-temperature chlorination reactor 1; First chlorine gas inlet 11; Ethylene gas inlet 12; Crude dichloroethane gas phase outlet 13; High-temperature reactor liquid phase inlet 14; Circulating material inlet 15; U-shaped circulation section 16; Gas-liquid separator 17; Spray section 18; Axial flow pump 19;

[0032] Product tower 2; Crude dichloroethane gas phase inlet 21; Product tower material outlet 22; Product tower gas phase outlet 23; Refined dichloroethane side stream outlet 24; Product tower liquid phase inlet 25;

[0033] Heavy component removal tower 3; Heavy component removal tower material inlet 31; Heavy component outlet 32; Heavy component removal tower gas phase outlet 33;

[0034] Light weight removal tower 4; Light weight removal tower liquid phase inlet 41; Light weight removal tower liquid phase outlet 42; Light weight removal tower gas phase outlet 43;

[0035] Low-temperature chlorination reactor 5; nitrogen inlet 51; second chlorine inlet 52; tail gas inlet 53; low-temperature reactor liquid phase outlet 54;

[0036] First condenser 61; reflux tank 62; second condenser 63; cryogenic tank 64; first buffer tank 65; neutralization tank 66; sodium hydroxide solution inlet 66-1; wastewater outlet 66-2; third condenser 67; second buffer tank 68; second buffer tank tail gas outlet 68-1; second buffer tank aqueous phase outlet 68-2; second buffer tank liquid phase outlet 68-3; fourth condenser 69; third buffer tank 70; third buffer tank tail gas outlet 70-1; third buffer tank liquid phase outlet 70-2; fifth condenser 71; fourth buffer tank 72. Detailed Implementation

[0037] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present utility model. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present utility model without creative effort are within the protection scope of the present utility model. Example 1

[0038] Depend on Figure 1 As shown, a production apparatus for producing dichloroethane by combining high and low temperature chlorination of ethylene includes a high temperature chlorination reactor 1, a product tower 2, a heavy removal tower 3, and a light removal tower 4.

[0039] The high-temperature chlorination reactor 1 is provided with a first chlorine gas inlet 11 and an ethylene gas inlet 12. The top of the high-temperature chlorination reactor 1 is provided with a crude dichloroethane gas phase outlet 13. The top of the high-temperature chlorination reactor 1 is also provided with a high-temperature reactor liquid phase inlet 14. The bottom of the high-temperature chlorination reactor 1 is provided with a circulating material inlet 15. The temperature of the high-temperature chlorination reactor is 105~125℃ and the pressure is 0.1~0.3MPa.

[0040] The product tower 2 has a crude dichloroethane gas inlet 21 and a product tower material outlet 22 at the bottom, a product tower gas outlet 23 at the top, and a refined dichloroethane side stream outlet 24 and a product tower liquid inlet 25 in the middle. The temperature at the top of the product tower 2 is 90~110℃, and the pressure is 0.005MPa~0.02MPa.

[0041] The deweight removal tower 3 has a material inlet 31 in the middle, a heavy component outlet 32 ​​at the bottom, and a gas phase outlet 33 at the top; the top temperature of the deweight removal tower 3 is 42-52℃, and the pressure is -0.070~-0.080MPa.

[0042] The light-weight removal tower 4 has a liquid phase inlet 41 and a liquid phase outlet 42 at the bottom and a gas phase outlet 43 at the top; the temperature at the top of the light-weight removal tower 4 is 75-85℃ and the pressure is 0.06~0.07MPa.

[0043] The crude dichloroethane gaseous outlet 13 of the high-temperature chlorination reactor 1 is connected to the crude dichloroethane gaseous inlet 21 of the product tower 2. The product tower material outlet 22 of the product tower 2 is connected to the heavy-duty tower material inlet 31 of the heavy-duty tower 3. The product tower gaseous outlet 23 of the product tower 2 is connected to the light-duty tower liquid inlet 41 of the light-duty tower 4. The light-duty tower liquid outlet 42 of the light-duty tower 4 is connected to the product tower liquid inlet 25 of the product tower 2.

[0044] It also includes a low-temperature chlorination reactor 5, which is equipped with a nitrogen inlet 51, a second chlorine inlet 52, a tail gas inlet 53, and a low-temperature reactor liquid phase outlet 54. The temperature of the low-temperature chlorination reactor 5 is 50-60℃. The low-temperature reactor liquid phase outlet 54 of the low-temperature chlorination reactor 5 is connected to the high-temperature reactor liquid phase inlet 14 of the high-temperature chlorination reactor 1; the product tower gas phase outlet 23 of the product tower 2 is connected to the tail gas inlet 53 of the low-temperature chlorination reactor 5.

[0045] The product tower gas phase outlet 23 of the product tower 2 and the light phase removal tower liquid phase inlet 41 of the light phase removal tower 4 are sequentially connected by a first condenser 61, a reflux tank 62, a second condenser 63, a cryogenic cooler 64, a first buffer tank 65, and a neutralization tank 66. The reflux tank 62 is connected to the product tower 2, the first buffer tank 65 is connected to the tail gas inlet 53 of the low-temperature chlorination reactor 5, and the neutralization tank 66 is equipped with a sodium hydroxide solution inlet 66-1 and a wastewater outlet 66-2.

[0046] The gas phase outlet 43 of the light-light removal tower 4 is connected to a third condenser 67, and a second buffer tank 68 is connected to the third condenser 67. The second buffer tank 68 is provided with a second buffer tank tail gas outlet 68-1, a second buffer tank aqueous phase outlet 68-2, and a second buffer tank liquid phase outlet 68-3. The second buffer tank aqueous phase outlet 68-2 is connected to a neutralization tank 66, and the second buffer tank liquid phase outlet 68-3 is connected to the light-light removal tower 4.

[0047] The de-weight tower 3 has a fourth condenser 69 connected to its gas phase outlet 33, and a third buffer tank 70 connected to the fourth condenser 69. The third buffer tank 70 has a third buffer tank tail gas outlet 70-1 and a third buffer tank liquid phase outlet 70-2. The third buffer tank liquid phase outlet 70-2 is connected to the de-weight tower 3.

[0048] The product tower material outlet 22 of the product tower 2 is connected to the circulating material inlet 15; the top of the low-temperature chlorination reactor 5 is provided with a fifth condenser 71; a fourth buffer tank 72 is provided between the low-temperature reactor liquid phase outlet 54 and the high-temperature reactor liquid phase inlet 14.

[0049] The high-temperature chlorination reactor 1 includes a U-shaped circulation section 16, a gas-liquid separation tank 17, and a spray section 18. The circulating material inlet 15, the first chlorine gas inlet 11, and the ethylene gas inlet 12 are located in the U-shaped circulation section 16. The high-temperature reactor liquid phase inlet 14 and the crude dichloroethane gas phase outlet 13 are located in the spray section 18. An axial flow pump 19 is provided at the bend of the U-shaped circulation section 16.

[0050] The production method of the production apparatus of this application includes the following steps:

[0051] (1) High-temperature chlorination reaction

[0052] Chlorine and ethylene enter the U-shaped circulation section 16 of the high-temperature chlorination reactor 1 through the first chlorine inlet 11 and the ethylene inlet 12, and mix with the crude dichloroethane in the U-shaped circulation section 16. The axial flow pump 19 provides power for the circulation of crude dichloroethane and controls the chlorine inlet flow rate. The ethylene inlet flow rate is controlled in cascade. The reaction between chlorine and ethylene takes place in the liquid phase. All the heat of reaction is used to vaporize the crude dichloroethane circulating liquid. The vaporized crude dichloroethane is sent downstream for purification through the crude dichloroethane gas phase outlet 13 at the top of the high-temperature chlorination reactor 1. The temperature of the high-temperature chlorination reactor 1 is 105~125℃ and the pressure is 0.1~0.3MPa.

[0053] (2) Purification of dichloroethane

[0054] Product Tower:

[0055] Crude dichloroethane gas from high-temperature chlorination reactor 1 enters product column 2 through crude dichloroethane gas inlet 21. The top temperature of product column 2 is 90~110℃, and the pressure is 0.005MPa~0.02MPa. The gas phase at the top of the column flows out through product column gas outlet 23 and is cooled in the first condenser 61. The liquid phase enters the reflux tank 62 of product column 2 and is returned to product column 2 by the product column reflux pump. The cooled gas phase is further cooled by the second condenser 63 and the cryogenic cooler 64. After passing through the first buffer tank 65, the cryogenically cooled liquid phase is sent to the desulfurization system. In light tower 4, the uncondensed gas phase is pressurized by the compressor and sent to low-temperature chlorination reactor 5. The pressure of product tower 2 is controlled by the flow rate of the bypass tail gas of the compressor. Qualified purified dichloroethane is collected from the purified dichloroethane side stream outlet 24 of product tower 2 and pumped out. The bottom material of the tower flows out through the product tower material outlet 22. Part of it is pumped to the de-heavy tower 3 to recover most of the dichloroethane remaining in the bottom material of the product tower, and the other part is sent to the circulating material inlet 15 of high-temperature chlorination reactor 1 to control the liquid level stability of high-temperature chlorination reactor 1.

[0056] b. De-weighting tower:

[0057] The bottom liquid phase of the product tower material outlet 22 enters the de-weighting tower 3 through the de-weighting tower material inlet 31. The tower top pressure is controlled at -0.070~-0.080MPa, and the tower top temperature is controlled at 42-52℃. The top gas of the de-weighting tower 3 is discharged through the de-weighting tower gas phase outlet 33. After being cooled in the fourth condenser 69, it enters the third buffer tank 70. Part of the liquid phase is sent to the de-weighting tower 3 as reflux through the third buffer tank liquid phase outlet 70-2, and part of it is pumped out as qualified dichloroethane through the third buffer tank tail gas outlet 70-1. The gas phase tail gas is then transported to the incineration unit by a vacuum pump. The heavy components at the bottom of the de-weighting tower are pumped to the incineration unit for incineration through the heavy components outlet 32.

[0058] c. Light tower removal:

[0059] The liquid phase in the first buffer tank 65 enters the neutralization tank 66. Sodium hydroxide solution is added to the neutralization tank 66 through the sodium hydroxide solution inlet 66-1 to remove hydrogen chloride from the liquid phase. The liquid phase after hydrogen chloride removal enters the light-light ... The condensed liquid phase separates into layers in the second buffer tank 68. The aqueous phase after separation is returned to the neutralization tank 66 from the aqueous phase outlet 68-2 of the second buffer tank, and the liquid phase is discharged from the liquid phase outlet 68-3 of the second buffer tank. Part of the liquid phase is sent to the light phase removal tower 4 as reflux, and part of the liquid phase is sent to the incineration unit for treatment. The tail gas in the second buffer tank is discharged from the tail gas outlet 68-1 of the second buffer tank and incinerated. The product at the bottom of the light phase removal tower is discharged through the liquid phase outlet 42 of the light phase removal tower and pumped to the liquid phase inlet 25 of the product tower for further distillation in the product tower 2.

[0060] (3) Low-temperature chlorination reaction

[0061] The uncondensed gaseous tail gas in the first buffer tank 65 is pressurized by the compressor and sent to the low-temperature chlorination reactor 5 through the tail gas inlet 53. Chlorine is added to the bottom of the low-temperature chlorination reactor 5 through the second chlorine inlet 52. The chlorine and tail gas mix and react in the low-temperature chlorination reactor 5. The low-temperature chlorination reactor 5 is equipped with sacrificial packing. The catalyst concentration in the low-temperature chlorination reactor 5 is maintained by corroding the sacrificial packing. Nitrogen enters the low-temperature chlorination reactor 5 through the nitrogen inlet 51 to control the oxygen content in the top tail gas. The gaseous phase at the top of the low-temperature chlorination reactor 5 enters the fifth condenser 71. The deep-cooled non-condensable gas is sent to the incineration unit for treatment. The liquid phase flows back to the low-temperature chlorination reactor 5. The liquid phase in the low-temperature chlorination reactor 5 is discharged from the low-temperature reactor liquid phase outlet 54. After passing through the fourth buffer tank 72, it is pumped to the high-temperature chlorination reactor 1 through the high-temperature reactor liquid phase inlet 14. The low-temperature chlorination reactor 5 is equipped with a cooling section, which uses circulating water to cool and control the temperature of the low-temperature chlorination reactor 5 at 50-60℃.

[0062] Table 1 below compares the experimental results of the high and low temperature combined chlorination reaction with those of high temperature chlorination and low temperature chlorination in this application.

[0063]

[0064] Although embodiments of the present 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 present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A production apparatus for producing dichloroethane by combining high and low temperature chlorination of ethylene with chlorine gas, characterized in that: This includes a high-temperature chlorination reactor, a product tower, a heavy-weight removal tower, and a light-weight removal tower; The high-temperature chlorination reactor is equipped with a first chlorine gas inlet and an ethylene gas inlet, and the top of the high-temperature chlorination reactor is equipped with a crude dichloroethane gas phase outlet. The product tower has a crude dichloroethane gas phase inlet and a product tower material outlet at the bottom, a product tower gas phase outlet at the top, and a refined dichloroethane side stream outlet and a product tower liquid phase inlet in the middle. The deweight removal tower has a material inlet in the middle, a heavy component outlet at the bottom, and a gas phase outlet at the top. The light-weight removal tower is provided with a liquid phase inlet and a liquid phase outlet at the bottom, and a gas phase outlet at the top. The crude dichloroethane gas phase outlet of the high-temperature chlorination reactor is connected to the crude dichloroethane gas phase inlet of the product tower. The product tower material outlet is connected to the heavy precipitator material inlet of the heavy precipitator. The product tower gas phase outlet is connected to the light precipitator liquid phase inlet of the light precipitator. The light precipitator liquid phase outlet is connected to the product tower liquid phase inlet of the product tower.

2. The production apparatus for producing dichloroethane by combining high and low temperature chlorination of ethylene with chlorine gas according to claim 1, characterized in that: It also includes a low-temperature chlorination reactor, which is equipped with a nitrogen inlet, a second chlorine inlet, a tail gas inlet, and a low-temperature reactor liquid phase outlet. The top of the high-temperature chlorination reactor is equipped with a high-temperature reactor liquid phase inlet, and the low-temperature reactor liquid phase outlet of the low-temperature chlorination reactor is connected to the high-temperature reactor liquid phase inlet of the high-temperature chlorination reactor. The product tower gas phase outlet of the product tower is connected to the tail gas inlet of the low-temperature chlorination reactor.

3. The production apparatus for producing dichloroethane by combining high and low temperature chlorination of ethylene with chlorine gas according to claim 1, characterized in that: The product tower gas phase outlet and the light phase removal tower liquid phase inlet of the light phase removal tower are sequentially connected by a first condenser, a reflux tank, a second condenser, a cryogenic tank, a first buffer tank, and a neutralization tank.

4. The production apparatus for producing dichloroethane by combining high and low temperature chlorination of ethylene with chlorine gas according to claim 3, characterized in that: The reflux tank is connected to the product tower, the first buffer tank is connected to the tail gas inlet of the low-temperature chlorination reactor, and the neutralization tank is equipped with a sodium hydroxide solution inlet and a wastewater outlet.

5. The production apparatus for producing dichloroethane by combining high and low temperature chlorination of ethylene with chlorine gas according to claim 3, characterized in that: The gas phase outlet of the light-light removal tower is connected to a third condenser, and a second buffer tank is connected to the third condenser. The second buffer tank is provided with a second buffer tank tail gas outlet, a second buffer tank aqueous phase outlet, and a second buffer tank liquid phase outlet. The second buffer tank aqueous phase outlet is connected to a neutralization tank, and the second buffer tank liquid phase outlet is connected to the light-light removal tower.

6. The production apparatus for producing dichloroethane by combining high and low temperature chlorination of ethylene with chlorine gas according to claim 1, characterized in that: The de-weighting tower has a fourth condenser connected to its gas phase outlet, and a third buffer tank connected to the fourth condenser. The third buffer tank has a third buffer tank tail gas outlet and a third buffer tank liquid phase outlet, and the third buffer tank liquid phase outlet is connected to the de-weighting tower.

7. The production apparatus for producing dichloroethane by combining high and low temperature chlorination of ethylene with chlorine according to claim 2, characterized in that: The high-temperature chlorination reactor is provided with a circulating material inlet at the bottom, and the product tower material outlet of the product tower is connected to the circulating material inlet. The top of the low-temperature chlorination reactor is equipped with a fifth condenser; A fourth buffer tank is provided between the liquid phase outlet of the low-temperature reactor and the liquid phase inlet of the high-temperature reactor.

8. The production apparatus for producing dichloroethane by combining high and low temperature chlorination of ethylene with chlorine gas according to claim 2, characterized in that: The product tower has a top temperature of 90~110℃ and a pressure of 0.005MPa~0.02MPa; The high-temperature chlorination reactor operates at a temperature of 105~125℃ and a pressure of 0.1~0.3MPa. The top temperature of the deweight removal tower is 42-52℃, and the pressure is -0.070~-0.080MPa; The top temperature of the light-weight removal tower is 75-85℃, and the pressure is 0.06~0.07MPa; The temperature of the low-temperature chlorination reactor is 50~60℃.

9. The production apparatus for producing dichloroethane by combining high and low temperature chlorination of ethylene with chlorine gas according to claim 7, characterized in that: The high-temperature chlorination reactor includes a U-shaped circulation section, a gas-liquid separation tank, and a spray section. The circulating material inlet, the first chlorine gas inlet, and the ethylene gas inlet are located in the U-shaped circulation section. The liquid phase inlet of the high-temperature reactor and the crude dichloroethane gas phase outlet are located in the spray section. An axial flow pump is installed at the bend of the U-shaped circulation section.

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