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

Abstract

The invention relates to the technical field of preparation of dichloroethane by chlorination, in particular to a production device and a production method 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 light component removal tower bottom liquid inlet are formed in the middle of the product tower; according to the invention, on the basis of reducing the consumption of steam and circulating water, the 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] The invention relates to the technical field of preparing ethylene dichloride by chlorination, and in particular to a production device and a production method for producing ethylene dichloride by combining high- and low-temperature chlorination of ethylene chlorine. Background Art

[0002] The direct chlorination of ethylene and chlorine to produce ethylene dichloride is a mature process, which is a chlorination reaction between chlorine and ethylene in the ethylene dichloride liquid phase at a certain temperature and pressure to produce 1,2-dichloroethane. At present, the direct chlorination process of ethylene chlorine has been widely used in industrial devices, mainly divided into low-temperature chlorination, medium-temperature chlorination and high-temperature chlorination. These methods have their own advantages in terms of energy consumption, equipment and investment costs, but there are also shortcomings:

[0003] ① Low-temperature chlorination method: Ethylene and chlorine react at 55°C, 0.1MPa, in the presence of ethylene dichloride solution and catalyst to produce ethylene dichloride. The advantages of low-temperature chlorination are mild reaction conditions, stable production, and low requirements for raw material purity. The disadvantages are that the reaction heat is not utilized, additional steam is required for distillation of ethylene dichloride, and the ethylene dichloride produced by the reaction needs to be washed with alkali and water, and catalysts need to be added, which produces wastewater.

[0004] ②Medium-temperature chlorination method: Ethylene and chlorine react at 85°C, 0.015MPa, in the presence of ethylene dichloride solution and catalyst to produce ethylene dichloride. The advantage of medium-temperature chlorination is that ethylene dichloride is discharged in gas phase, the product is of high purity, no alkali washing or water washing is required, and no catalyst addition is required. The disadvantage is that the reaction heat is not utilized, and additional steam is required for distillation of ethylene dichloride.

[0005] ③ High temperature chlorination method: Ethylene and chlorine react at 115℃, 0.1MPa, in the presence of ethylene dichloride solution and catalyst to produce ethylene dichloride. The advantage of high temperature chlorination is that ethylene dichloride is discharged in gas phase, no alkali washing or water washing is required, no catalyst addition is required, and the reaction heat is used for dichloroethane distillation. The disadvantage is that the reaction conditions are difficult to control, and the mother liquor needs to be continuously discharged to control the catalyst content. In order to control the oxygen content in the tail gas, a large amount of excess ethylene is required, and this part of the tail gas is not recycled and treated, resulting in a large waste of raw materials. Summary of the invention

[0006] In view of the above situation, in order to overcome the defects of the prior art, the present invention provides a production device and a production method for producing ethylene dichloride by combining high and low temperature chlorination of ethylene chlorine, so as to reduce the energy consumption and material consumption of producing ethylene dichloride by chlorination of ethylene chlorine.

[0007] To achieve the above object, the present invention provides the following technical solution: a production device for producing ethylene dichloride by combining high and low temperature chlorination of ethylene 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 provided with a first chlorine gas inlet and an ethylene gas inlet, and the top of the high temperature chlorination reactor is provided with a crude dichloroethane gas phase outlet;

[0009] The product tower is provided with 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 line outlet and a light tower bottom liquid inlet at the middle of the tower;

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

[0011] The de-lightness tower has a de-lightness tower liquid phase inlet and a de-lightness tower liquid phase outlet at the bottom, and a de-lightness tower 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 of the product tower is connected to the de-heavy tower material inlet of the de-heavy tower, the product tower gas phase outlet of the product tower is connected to the de-light tower liquid phase inlet of the de-light tower, and the de-light tower liquid phase outlet of the de-light tower is connected to the de-light tower bottom liquid inlet of the product tower.

[0013] Furthermore, it also includes a low-temperature chlorination reactor, which is provided 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 provided with a high-temperature reactor liquid phase inlet; 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 product tower gas phase outlet of the product tower and the light-removal tower liquid phase inlet of the light-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 provided with a sodium hydroxide solution inlet and a wastewater outlet.

[0016] Furthermore, the gas phase outlet of the 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 water phase outlet and a second buffer tank liquid phase outlet. The second buffer tank water phase outlet is connected to a neutralization tank, and the second buffer tank liquid phase outlet is connected to the light-removal tower.

[0017] Furthermore, a fourth condenser is connected to the gas phase outlet of the deweighting 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 deweighting tower.

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

[0019] A fifth condenser is provided on the top of the low-temperature chlorination reactor;

[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° C., and the pressure is 0.005 MPa-0.02 MPa;

[0022] The temperature of the high temperature chlorination reactor is 105-125°C and the pressure is 0.1-0.3MPa;

[0023] The top temperature of the deweighting tower is 42-52°C, and the pressure is -0.070 to -0.080 MPa;

[0024] The top temperature of the light removal tower is 75-85°C and the pressure is 0.06-0.07MPa;

[0025] The temperature of the low-temperature chlorination reactor is 50-60°C.

[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 arranged in the U-shaped circulation section, the liquid phase inlet of the high-temperature reactor and the crude dichloroethane gas phase outlet are arranged in the spray section, and an axial flow pump is provided at the bend of the U-shaped circulation section.

[0027] A production method of a production device for producing ethylene dichloride by combining high and low temperature chlorination of ethylene chlorine,

[0028] (1) High temperature chlorination reaction

[0029] Chlorine and ethylene enter the U-shaped circulation section of the high-temperature chlorination reactor from the first chlorine inlet and the ethylene inlet, and are mixed with the crude ethylene dichloride in the U-shaped circulation section. The axial flow pump provides power for the circulation of the crude ethylene dichloride, and controls the intake amount of chlorine and the intake amount of ethylene in cascade. The reaction of chlorine and ethylene is carried out in the liquid phase, and all the reaction heat is used to vaporize the crude ethylene dichloride circulating liquid. The vaporized crude ethylene dichloride is sent to the downstream through the crude ethylene dichloride gas phase outlet at the top of the high-temperature chlorination reactor for refining. The temperature of the high-temperature chlorination reactor is 105-125° C. and the pressure is 0.1-0.3 MPa.

[0030] (2) Ethylene dichloride refining

[0031] aProduct Tower:

[0032] The crude dichloroethane gas phase from the high-temperature chlorination reactor enters the product tower through the crude dichloroethane gas phase inlet, the product tower top temperature is 90-110°C, the pressure is 0.005MPa-0.02Mpa, the tower top gas phase flows out through the product tower gas phase outlet, is cooled in the first condenser, the liquid phase enters the reflux tank of the product tower, and is refluxed to the product tower by the product tower reflux pump, the cooled gas phase is deep-cooled by the second condenser and the deep-cooler, and after passing through the first buffer tank, the deep-cooled liquid phase is sent to the light-removing tower, the uncondensed gas phase is pressurized by the compressor and sent to the low-temperature chlorination reactor, the product tower pressure is controlled by the compressor bypass tail gas flow rate, the product tower extracts qualified refined dichloroethane from the refined dichloroethane side line extraction outlet, and pumps it out, the tower bottom material flows out through the product tower material outlet, a part of it is pumped to the heavy-removing tower to recover most of the dichloroethane remaining in the product tower bottom material, and the other part is sent to the circulating material inlet of the high-temperature chlorination reactor to control the liquid level stability of the high-temperature chlorination reactor;

[0033] b. Weight removal tower:

[0034] The bottom liquid phase of the product tower material outlet enters the de-weighting tower through the de-weighting tower material inlet, the tower top pressure is controlled at -0.070~-0.080MPa, the tower top temperature is controlled at 42-52℃, the top gas of the de-weighting tower is discharged from the gas phase outlet of the de-weighting tower, and enters the third buffer tank after being cooled in the fourth condenser, wherein a part of the liquid phase is sent to the de-weighting tower as reflux, and a part is pumped out as qualified dichloroethane, wherein the gas phase tail gas is transported to the incineration device after the vacuum pump, and the heavy component at the bottom of the de-weighting tower is pumped to the incineration unit for incineration treatment through the heavy component outlet;

[0035] c Light removal tower:

[0036] The liquid phase in the first buffer tank enters the neutralization tank, and the sodium hydroxide solution is added to the neutralization tank from the sodium hydroxide solution inlet to remove the hydrogen chloride in the liquid phase. The liquid phase after the hydrogen chloride is removed enters the lightness removal tower from the liquid phase inlet of the lightness removal tower, and the waste water is discharged from the waste water outlet of the neutralization tank. The tower top pressure is controlled at 0.06-0.07MPa, and the tower top temperature is controlled at 75-85°C. The gas phase at the top of the lightness removal tower is discharged from the gas phase outlet of the lightness removal tower and enters the third condenser. The condensed liquid phase is layered in the second buffer tank, and the layered water phase returns to the neutralization tank. A part of the liquid phase is sent to the lightness removal tower as reflux, and a part is sent to the incineration device for treatment. The tail gas in the second buffer tank is discharged and incinerated, and the product at the bottom of the lightness removal tower is discharged through the liquid phase outlet of the lightness removal tower and pumped to the liquid inlet of the bottom of the lightness removal tower to continue distillation in the product tower;

[0037] (3) Low temperature chlorination reaction

[0038] The uncondensed gaseous tail gas in the first buffer tank is pressurized by the compressor and sent to the low-temperature chlorination reactor through the tail gas inlet. Chlorine is added to the bottom of the low-temperature chlorination reactor through the second chlorine inlet. The chlorine and tail gas are mixed and reacted in the low-temperature chlorination reactor. A sacrificial filler is provided in the low-temperature chlorination reactor. The catalyst concentration in the low-temperature chlorination reactor is ensured by corroding the sacrificial filler. Nitrogen enters the low-temperature chlorination reactor through the nitrogen inlet to control the oxygen content in the top tail gas. The gas phase at the top of the low-temperature chlorination reactor enters the fifth condenser. The non-condensable gas after deep cooling is sent to the incineration device for treatment. The liquid phase flows back to the low-temperature chlorination reactor. The liquid phase in the low-temperature chlorination reactor is discharged from the liquid phase outlet of the low-temperature reactor. After passing through the fourth buffer tank, it is pumped into the high-temperature chlorination reactor from the liquid phase inlet of the high-temperature reactor. A cooling section is provided on the low-temperature chlorination reactor. The temperature of the low-temperature chlorination reactor is controlled at 50-60°C by circulating water cooling.

[0039] Compared with the prior art, the present invention has the following beneficial effects:

[0040] The invention reduces the consumption of steam and circulating water and utilizes the reaction tail gas to react with chlorine gas again to generate ethylene dichloride, thereby reducing the amount of waste gas generated and improving the conversion rate of raw materials. The utilization rate of raw material ethylene for high-temperature chlorination is increased from 77% to 95%. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 A schematic diagram of a connection structure of an embodiment of the present invention;

[0042] In the figure:

[0043] 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 separation tank 17; spray section 18; axial flow pump 19;

[0044] Product tower 2; crude ethylene dichloride gas phase inlet 21; product tower material outlet 22; product tower gas phase outlet 23; refined ethylene dichloride side line outlet 24; light tower bottom liquid inlet 25;

[0045] De-weighting tower 3; de-weighting tower material inlet 31; heavy component outlet 32; de-weighting tower gas phase outlet 33;

[0046] Lightness removal tower 4; Lightness removal tower liquid phase inlet 41; Lightness removal tower liquid phase outlet 42; Lightness removal tower gas phase outlet 43;

[0047] Low temperature chlorination reactor 5; nitrogen gas inlet 51; second chlorine gas inlet 52; tail gas inlet 53; low temperature reactor liquid phase outlet 54;

[0048] The first condenser 61; the reflux tank 62; the second condenser 63; the cryogenic cooler 64; the first buffer tank 65; the neutralization tank 66; the sodium hydroxide solution inlet 66-1; the wastewater outlet 66-2; the third condenser 67; the second buffer tank 68; the second buffer tank tail gas outlet 68-1; the second buffer tank water phase outlet 68-2; the second buffer tank liquid phase outlet 68-3; the fourth condenser 69; the third buffer tank 70; the third buffer tank tail gas outlet 70-1; the third buffer tank liquid phase outlet 70-2; the fifth condenser 71; the fourth buffer tank 72. DETAILED DESCRIPTION

[0049] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments; based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0050] Embodiment 1:

[0051] Depend on Figure 1 As shown, a production device for producing ethylene dichloride by combining high and low temperature chlorination of ethylene chlorine includes a high temperature chlorination reactor 1, a product tower 2, a heavy removal tower 3, and a light removal tower 4;

[0052] The high temperature chlorination reactor 1 is provided with a first chlorine gas inlet 11 and an ethylene gas inlet 12, and a crude dichloroethane gas phase outlet 13 is provided at the top of the high temperature chlorination reactor 1; a high temperature reactor liquid phase inlet 14 is also provided at the top of the high temperature chlorination reactor 1, and a circulating material inlet 15 is provided at the bottom of the high temperature chlorination reactor 1. The temperature of the high temperature chlorination reactor is 105-125°C and the pressure is 0.1-0.3MPa;

[0053] The bottom of the product tower 2 is provided with a crude dichloroethane gas phase inlet 21 and a product tower material outlet 22, the top of the tower is provided with a product tower gas phase outlet 23, the middle of the tower is provided with a refined dichloroethane side line outlet 24 and a light tower bottom liquid inlet 25; the top temperature of the product tower 2 is 90-110°C, and the pressure is 0.005MPa-0.02MPa;

[0054] The deweighting tower 3 has a deweighting tower material inlet 31 in the middle, a heavy component outlet 32 ​​at the bottom, and a deweighting tower gas phase outlet 33 at the top; the top temperature of the deweighting tower 3 is 42-52°C, and the pressure is -0.070 to -0.080MPa;

[0055] The de-lightening tower 4 has a de-lightening tower liquid phase inlet 41 and a de-lightening tower liquid phase outlet 42 at the bottom, and a de-lightening tower gas phase outlet 43 at the top; the top temperature of the de-lightening tower 4 is 75-85° C., and the pressure is 0.06-0.07 MPa;

[0056] The crude dichloroethane gas phase outlet 13 of the high-temperature chlorination reactor 1 is connected to the crude dichloroethane gas phase inlet 21 of the product tower 2, the product tower material outlet 22 of the product tower 2 is connected to the de-weighting tower material inlet 31 of the de-weighting tower 3, the product tower gas phase outlet 23 of the product tower 2 is connected to the de-weighting tower liquid phase inlet 41 of the de-weighting tower 4, and the de-weighting tower liquid phase outlet 42 of the de-weighting tower 4 is connected to the de-weighting tower bottom liquid inlet 25 of the product tower 2.

[0057] The low temperature chlorination reactor 5 is also included. The low temperature chlorination reactor 5 is provided 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° C. 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.

[0058] A first condenser 61, a reflux tank 62, a second condenser 63, a cryocooler 64, a first buffer tank 65 and a neutralization tank 66 are sequentially connected between the product tower gas phase outlet 23 of the product tower 2 and the light-removal tower liquid phase inlet 41 of the light-removal tower 4. 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 provided with a sodium hydroxide solution inlet 66-1 and a wastewater outlet 66-2.

[0059] The light-removal tower gas phase outlet 43 of the 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 water phase outlet 68-2 and a second buffer tank liquid phase outlet 68-3. The second buffer tank water phase outlet 68-2 is connected to the neutralization tank 66, and the second buffer tank liquid phase outlet 68-3 is connected to the light-removal tower 4.

[0060] The deweighting tower gas phase outlet 33 of the deweighting tower 3 is connected to a fourth condenser 69, and a third buffer tank 70 is connected to the fourth condenser 69. The third buffer tank 70 is provided with a third buffer tank tail gas outlet 70-1 and a third buffer tank liquid phase outlet 70-2, and the third buffer tank liquid phase outlet 70-2 is connected to the deweighting tower 3.

[0061] The product tower material outlet 22 of the product tower 2 is connected to the circulating material inlet 15; a fifth condenser 71 is provided on the top of the low-temperature chlorination reactor 5; 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.

[0062] 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 arranged in the U-shaped circulation section 16. The high-temperature reactor liquid phase inlet 14 and the crude dichloroethane gas phase outlet 13 are arranged in the spray section 18. An axial flow pump 19 is provided at the bend of the U-shaped circulation section 16.

[0063] The production method of the production device for producing ethylene dichloride by combining high and low temperature chlorination of ethylene chlorine comprises the following steps:

[0064] (1) High temperature chlorination reaction

[0065] 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 are mixed with the crude ethylene dichloride in the U-shaped circulation section 16. The axial flow pump 19 provides power for the circulation of the crude ethylene dichloride, and controls the intake amount of chlorine and the intake amount of ethylene in cascade. The reaction of chlorine and ethylene is carried out in the liquid phase, and the reaction heat is all used to vaporize the crude ethylene dichloride circulating liquid. The vaporized crude ethylene dichloride is sent to the downstream through the crude ethylene dichloride gas phase outlet 13 at the top of the high-temperature chlorination reactor 1 for refining. The temperature of the high-temperature chlorination reactor is 105-125° C. and the pressure is 0.1-0.3 MPa.

[0066] (2) Ethylene dichloride refining

[0067] aProduct Tower:

[0068] The crude dichloroethane gas phase from the high temperature chlorination reactor 1 enters the product tower 2 through the crude dichloroethane gas phase inlet 21. The top temperature of the product tower 2 is 90-110°C and the pressure is 0.005MPa-0.02Mpa. The gas phase at the top of the tower flows out through the product tower gas phase outlet 23, is cooled in the first condenser 61, and the liquid phase enters the reflux tank 62 of the product tower 2. The product tower reflux pump refluxes to the product tower 2. The cooled gas phase is deep-cooled by the second condenser 63 and the deep-cooler 64. After passing through the first buffer tank 65, the deep-cooled liquid phase is sent to the degassing tank 62. Light tower 4, the uncondensed gas phase is pressurized by the compressor and sent to the low-temperature chlorination reactor 5, the pressure of the product tower 2 is controlled by the flow rate of the bypass tail gas of the compressor, the product tower 2 extracts qualified refined ethylene dichloride from the refined ethylene dichloride side line extraction port 24, pumps it out, the bottom material flows out through the product tower material outlet 22, a part of it is pumped to the de-weighting tower 3, and most of the residual ethylene dichloride in the product tower bottom material is recovered, and the other part is sent to the circulating material inlet 15 of the high-temperature chlorination reactor 1 to control the liquid level stability of the high-temperature chlorination reactor 1;

[0069] b. Weight removal tower:

[0070] 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, and 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 from the de-weighting tower gas phase outlet 33, and enters the third buffer tank 70 after being cooled in the fourth condenser 69, wherein a part of the liquid phase is sent to the de-weighting tower 3 through the third buffer tank liquid phase outlet 70-2 as reflux, and a part of the liquid phase is pumped out through the third buffer tank tail gas outlet 70-1 as qualified dichloroethane, wherein the gas phase tail gas is transported to the incineration device after the vacuum pump, and the heavy component at the bottom of the de-weighting tower is pumped to the incineration unit through the heavy component outlet 32 ​​for incineration treatment;

[0071] c Light removal tower:

[0072] The liquid phase in the first buffer tank 65 enters the neutralization tank 66, and the sodium hydroxide solution is added to the neutralization tank 66 from the sodium hydroxide solution inlet 66-1 to remove the hydrogen chloride in the liquid phase. The liquid phase after the hydrogen chloride is removed enters the lightness removal tower 4 from the lightness removal tower liquid phase inlet 41, and the waste water is discharged from the waste water outlet 66-2 of the neutralization tank 66. The tower top pressure is controlled at 0.06-0.07MPa, and the tower top temperature is controlled at 75-85°C. The gas phase at the top of the lightness removal tower 4 is discharged from the lightness removal tower gas phase outlet 43 and enters the third condenser 67. The condensed liquid phase is separated into layers in the second buffer tank 68, and the separated water phase is returned to the neutralization tank 66 from the water phase outlet 68-2 of the second buffer tank. The liquid phase is discharged from the liquid phase outlet 68-3 of the second buffer tank, a part of which is sent to the light removal tower 4 as reflux, and a part of which is sent to the incineration device 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 removal tower is discharged through the liquid phase outlet 42 of the light removal tower and pumped to the liquid inlet 25 of the bottom of the light removal tower to continue distillation in the product tower 2.

[0073] (3) Low temperature chlorination reaction

[0074] 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 the tail gas are mixed and reacted in the low-temperature chlorination reactor 5. A sacrificial filler is provided in the low-temperature chlorination reactor 5. The catalyst concentration in the low-temperature chlorination reactor 5 is ensured by corroding the sacrificial filler. Nitrogen enters the low-temperature chlorination reactor 5 through the nitrogen inlet 51 to control the oxygen content in the top tail gas. The gas phase at the top of the low-temperature chlorination reactor 5 enters the fifth condenser 71. The non-condensable gas after deep cooling is sent to the incineration device 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 liquid phase outlet 54 of the low-temperature reactor. After passing through the fourth buffer tank 72, it is pumped into the high-temperature chlorination reactor 1 through the liquid phase inlet 14 of the high-temperature reactor. A cooling section is provided on the low-temperature chlorination reactor 5. The temperature of the low-temperature chlorination reactor 5 is controlled at 50-60°C by circulating water cooling.

[0075] The following table 1 compares the experimental results of the high and low temperature combined chlorination reaction of the present application with the high temperature chlorination and the low temperature chlorination.

[0076] Table 1 Comparison of main utility consumption and ethylene consumption

[0077]

[0078] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A production device for producing ethylene dichloride by combining high and low temperature chlorination of ethylene chlorine, characterized in that: Including high temperature chlorination reactor, product tower, heavy removal tower, light removal tower; The high temperature chlorination reactor is provided with a first chlorine gas inlet and an ethylene gas inlet, and the top of the high temperature chlorination reactor is provided with a crude dichloroethane gas phase outlet; The product tower is provided with 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 line outlet and a light tower bottom liquid inlet at the middle of the tower; The deweighting tower has a deweighting tower material inlet in the middle, a heavy component outlet at the bottom, and a deweighting tower gas phase outlet at the top. The de-lightness tower has a de-lightness tower liquid phase inlet and a de-lightness tower liquid phase outlet at the bottom, and a de-lightness tower 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 of the product tower is connected to the de-heavy tower material inlet of the de-heavy tower, the product tower gas phase outlet of the product tower is connected to the de-light tower liquid phase inlet of the de-light tower, and the de-light tower liquid phase outlet of the de-light tower is connected to the de-light tower bottom liquid inlet of the product tower.

2. The production device for producing ethylene dichloride by combining high and low temperature chlorination of ethylene chlorine according to claim 1, characterized in that: It also includes a low-temperature chlorination reactor, which is provided 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 provided with a high-temperature reactor liquid phase inlet; 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 device for producing ethylene dichloride by combining high and low temperature chlorination of ethylene chlorine according to claim 1, characterized in that: 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 product tower gas phase outlet of the product tower and the light-removal tower liquid phase inlet of the light-removal tower.

4. The production device for producing ethylene dichloride by combining high and low temperature chlorination of ethylene chlorine 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 provided with a sodium hydroxide solution inlet and a wastewater outlet.

5. The production device for producing ethylene dichloride by combining high and low temperature chlorination of ethylene chlorine according to claim 3, characterized in that: The gas phase outlet of the 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 water phase outlet and a second buffer tank liquid phase outlet. The second buffer tank water phase outlet is connected to a neutralization tank, and the second buffer tank liquid phase outlet is connected to the light-removal tower.

6. The production device for producing ethylene dichloride by combining high and low temperature chlorination of ethylene chlorine according to claim 1, characterized in that: The gas phase outlet of the deweighting tower is connected to a fourth condenser, 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 deweighting tower.

7. The production device for producing ethylene dichloride by combining high and low temperature chlorination of ethylene chlorine according to claim 1, characterized in that: A circulating material inlet is provided at the bottom of the high temperature chlorination reactor, and a product tower material outlet of the product tower is connected to the circulating material inlet; A fifth condenser is provided on the top of the low-temperature chlorination reactor; 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 device for producing ethylene dichloride by combining high and low temperature chlorination of ethylene chlorine according to claim 1, characterized in that: The top temperature of the product tower is 90-110° C., and the pressure is 0.005 MPa-0.02 MPa; The temperature of the high temperature chlorination reactor is 105-125°C and the pressure is 0.1-0.3MPa; The top temperature of the deweighting tower is 42-52°C, and the pressure is -0.070 to -0.080 MPa; The top temperature of the light removal tower is 75-85°C and the pressure is 0.06-0.07MPa; The temperature of the low-temperature chlorination reactor is 50-60°C.

9. The production device for producing ethylene dichloride by combining high and low temperature chlorination of ethylene chlorine according to claim 1, characterized in that: The high-temperature chlorination reactor comprises 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 arranged in the U-shaped circulation section. The liquid phase inlet of the high-temperature reactor and the crude dichloroethane gas phase outlet are arranged in the spray section. An axial flow pump is arranged at the bend of the U-shaped circulation section.

10. The production method of the production device for producing ethylene dichloride by combining high and low temperature chlorination of ethylene chlorine according to any one of claims 1 to 9, characterized in that: (1) High temperature chlorination reaction Chlorine and ethylene enter the U-shaped circulation section of the high-temperature chlorination reactor from the first chlorine inlet and the ethylene inlet, and are mixed with the crude ethylene dichloride in the U-shaped circulation section. The axial flow pump provides power for the circulation of the crude ethylene dichloride, and controls the intake amount of chlorine and the intake amount of ethylene in cascade. The reaction of chlorine and ethylene is carried out in the liquid phase, and all the reaction heat is used to vaporize the crude ethylene dichloride circulating liquid. The vaporized crude ethylene dichloride is sent to the downstream through the crude ethylene dichloride gas phase outlet at the top of the high-temperature chlorination reactor for refining. The temperature of the high-temperature chlorination reactor is 105-125° C. and the pressure is 0.1-0.3 MPa. (2) Ethylene dichloride refining aProduct Tower: The crude dichloroethane gas phase from the high-temperature chlorination reactor enters the product tower through the crude dichloroethane gas phase inlet, the product tower top temperature is 90-110°C, the pressure is 0.005MPa-0.02Mpa, the tower top gas phase flows out through the product tower gas phase outlet, is cooled in the first condenser, the liquid phase enters the reflux tank of the product tower, and is refluxed to the product tower by the product tower reflux pump, the cooled gas phase is deep-cooled by the second condenser and the deep-cooler, and after passing through the first buffer tank, the deep-cooled liquid phase is sent to the light-removing tower, the uncondensed gas phase is pressurized by the compressor and sent to the low-temperature chlorination reactor, the product tower pressure is controlled by the compressor bypass tail gas flow rate, the product tower extracts qualified refined dichloroethane from the refined dichloroethane side line extraction outlet, and pumps it out, the tower bottom material flows out through the product tower material outlet, a part of it is pumped to the heavy-removing tower to recover most of the dichloroethane remaining in the product tower bottom material, and the other part is sent to the circulating material inlet of the high-temperature chlorination reactor to control the liquid level stability of the high-temperature chlorination reactor; b. Weight removal tower: The bottom liquid phase of the product tower material outlet enters the de-weighting tower through the de-weighting tower material inlet, the tower top pressure is controlled at -0.070~-0.080MPa, the tower top temperature is controlled at 42-52℃, the top gas of the de-weighting tower is discharged from the gas phase outlet of the de-weighting tower, and enters the third buffer tank after being cooled in the fourth condenser, wherein a part of the liquid phase is sent to the de-weighting tower as reflux, and a part is pumped out as qualified dichloroethane, wherein the gas phase tail gas is transported to the incineration device after the vacuum pump, and the heavy component at the bottom of the de-weighting tower is pumped to the incineration unit for incineration treatment through the heavy component outlet; c Light removal tower: The liquid phase in the first buffer tank enters the neutralization tank, and the sodium hydroxide solution is added to the neutralization tank from the sodium hydroxide solution inlet to remove the hydrogen chloride in the liquid phase. The liquid phase after the hydrogen chloride is removed enters the lightness removal tower from the liquid phase inlet of the lightness removal tower, and the waste water is discharged from the waste water outlet of the neutralization tank. The tower top pressure is controlled at 0.06-0.07MPa, and the tower top temperature is controlled at 75-85°C. The gas phase at the top of the lightness removal tower is discharged from the gas phase outlet of the lightness removal tower and enters the third condenser. The condensed liquid phase is layered in the second buffer tank, and the layered water phase returns to the neutralization tank. A part of the liquid phase is sent to the lightness removal tower as reflux, and a part is sent to the incineration device for treatment. The tail gas in the second buffer tank is discharged and incinerated, and the product at the bottom of the lightness removal tower is discharged through the liquid phase outlet of the lightness removal tower and pumped to the liquid inlet of the bottom of the lightness removal tower to continue distillation in the product tower; (3) Low temperature chlorination reaction The uncondensed gaseous tail gas in the first buffer tank is pressurized by the compressor and sent to the low-temperature chlorination reactor through the tail gas inlet. Chlorine is added to the bottom of the low-temperature chlorination reactor through the second chlorine inlet. The chlorine and tail gas are mixed and reacted in the low-temperature chlorination reactor. A sacrificial filler is provided in the low-temperature chlorination reactor. The catalyst concentration in the low-temperature chlorination reactor is ensured by corroding the sacrificial filler. Nitrogen enters the low-temperature chlorination reactor through the nitrogen inlet to control the oxygen content in the top tail gas. The gas phase at the top of the low-temperature chlorination reactor enters the fifth condenser. The non-condensable gas after deep cooling is sent to the incineration device for treatment. The liquid phase flows back to the low-temperature chlorination reactor. The liquid phase in the low-temperature chlorination reactor is discharged from the liquid phase outlet of the low-temperature reactor. After passing through the fourth buffer tank, it is pumped into the high-temperature chlorination reactor from the liquid phase inlet of the high-temperature reactor. A cooling section is provided on the low-temperature chlorination reactor. The temperature of the low-temperature chlorination reactor is controlled at 50-60°C by circulating water cooling.

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