阅读说明：本技术 分离氯甲烷中氯乙烷的系统及方法、合成氯甲烷的系统 (System and method for separating chloroethane from methyl chloride and system for synthesizing methyl chloride ) 是由 丁军博 陈国辉 李军 高军锋 杜鹃 于 2021-11-01 设计创作，主要内容包括：本发明提供了分离氯甲烷中氯乙烷的系统及方法、合成氯甲烷的系统,所述分离氯甲烷中氯乙烷的系统包括：压缩装置、双向换热装置、氯乙烷塔和氯乙烷罐；所述压缩装置与所述双向换热装置连接,所述双向换热装置与所述氯乙烷塔连接,所述氯乙烷塔塔釜与所述氯乙烷罐连接,所述氯乙烷塔塔顶与所述双向换热装置连接。本发明中提供的分离氯甲烷中氯乙烷的系统,能够有效的分离出氯甲烷中氯乙烷。在分离氯乙烷的同时,本发明充分利用了分离系统中的热能,从而可以省略对经压缩后的含有氯乙烷的氯甲烷气体进行降温的装置,以及对氯乙烷塔塔顶分离出来的氯甲烷气体进行预热的装置,装置简单,工艺流程也得到了简化。(The invention provides a system and a method for separating chloroethane from methyl chloride and a system for synthesizing methyl chloride, wherein the system for separating chloroethane from methyl chloride comprises the following components: the device comprises a compression device, a bidirectional heat exchange device, a chloroethane tower and a chloroethane tank; the compression device is connected with the bidirectional heat exchange device, the bidirectional heat exchange device is connected with the chloroethane tower, the chloroethane tower kettle is connected with the chloroethane tank, and the top of the chloroethane tower is connected with the bidirectional heat exchange device. The system for separating the chloroethane from the methyl chloride provided by the invention can effectively separate the chloroethane from the methyl chloride. The invention makes full use of the heat energy in the separation system while separating the chloroethane, thereby omitting a device for cooling the compressed chloroethane-containing methyl chloride gas and a device for preheating the methyl chloride gas separated from the top of the chloroethane tower, and having simple device and simplified process flow.)

1. A system for separating ethyl chloride from methyl chloride, the system comprising:

the device comprises a compression device, a bidirectional heat exchange device, a chloroethane tower and a chloroethane tank;

the compression device is connected with the bidirectional heat exchange device, the bidirectional heat exchange device is connected with the chloroethane tower, the chloroethane tower kettle is connected with the chloroethane tank, and the top of the chloroethane tower is connected with the bidirectional heat exchange device.

2. The system of claim 1, further comprising:

a methyl chloride feed line;

the inlet of the chloromethane feed pipeline is connected with the bidirectional heat exchange device, and the outlet of the chloromethane feed pipeline is communicated with the organic silicon monomer synthesis system.

3. The system of claim 2, further comprising:

a methyl chloride tank and a methyl chloride storage pipeline;

one end of the methyl chloride storage pipeline is connected with the methyl chloride feeding pipeline, and the other end of the methane storage pipeline is connected with the methyl chloride tank.

4. The system of claim 3, further comprising:

a condensing unit;

condensing equipment sets up on the methane storage pipeline, and be located chloromethane jar front end.

5. The system of claim 4, further comprising:

a tail gas absorption system;

the tail gas absorption system is connected with the condensing device through a pipeline, and the tail gas absorption system absorbs methyl chloride in the non-condensable gas passing through the condensing device by adopting methanol.

6. A method for separating ethyl chloride from methyl chloride by using the system of any one of claims 1 to 5, wherein the method comprises the following steps:

sending methyl chloride gas containing ethyl chloride to the compression device to be compressed to obtain high-temperature high-pressure gas, wherein the high-temperature high-pressure gas firstly enters the bidirectional heat exchange device and then enters the ethyl chloride tower to be rectified, and the rectified ethyl chloride is discharged from the ethyl chloride tower kettle and collected into the ethyl chloride tank; the methyl chloride gas is discharged from the top of the ethyl chloride tower, and also enters the two-way heat exchange device after being discharged, and in the two-way heat exchange device, the high-temperature and high-pressure gas exchanges heat with the methyl chloride gas discharged from the top of the ethyl chloride tower;

and the temperature of the methyl chloride gas discharged from the top of the ethyl chloride tower is raised after heat exchange, and the methyl chloride gas is sent to a rear-end monomer synthesis system for synthesis reaction.

7. The method according to claim 6, wherein the high-temperature high-pressure gas has a pressure of 1000kPa or more and a temperature of 150 ℃ or more.

8. The method according to claim 6, characterized in that a part of the methyl chloride gas discharged from the top of the ethyl chloride tower is sent to a back-end monomer synthesis system for synthesis reaction, and the other part is collected in a methyl chloride tank through condensation.

9. The method according to claim 8, characterized in that the uncondensed gas after condensation is sent to a tail gas absorption system, methanol is adopted in the tail gas absorption system to absorb methyl chloride in the tail gas, the methanol dissolved with the methyl chloride after absorption is sent to a front-end methyl chloride synthesis system to be used as a raw material, and the absorbed tail gas is sent to incineration.

10. A system for synthesizing methyl chloride, the system comprising:

the system for separating ethyl chloride from methyl chloride, the methyl chloride synthesis system and the rectification system of any one of claims 1 to 5;

the methyl chloride synthesis system is connected with the rectification system, the rectification system is connected with the system for separating ethyl chloride from methyl chloride, and a tail gas absorption system in the system for separating ethyl chloride from methyl chloride is connected with the methyl chloride synthesis system;

the methyl chloride synthesis system is used for synthesizing hydrogen chloride and methanol to generate a crude methyl chloride product, and the rectification system is used for removing impurities in the crude methyl chloride product, wherein the impurities comprise hydrogen chloride, methanol, siloxane and dimethyl ether.

Technical Field

The invention relates to the technical field of preparation of methane chloride, in particular to a system and a method for separating chloroethane from methyl chloride and a system for synthesizing methyl chloride.

Background

Currently, methyl chloride is an important raw material in the organic synthesis industry, and is mainly used as a raw material of methyl chlorosilane for producing organic silicide. During the synthesis of methyl chloride, impurities such as hydrogen chloride, methanol, water, dimethyl ether, siloxane, chloroethane and the like can be generated, and the method for treating the impurities in the traditional process comprises the following steps: the chloromethane synthesis gas enters an acid washing tower after being cooled by circulating water, excessive hydrogen chloride gas and water in the synthesis gas are condensed and washed by circulating cooling acid at the temperature of 20 ℃, then the synthesis gas enters an alkaline washing tower, the synthesis gas is washed by 10% sodium hydroxide solution, the residual HCl gas in the synthesis gas is completely neutralized, and then the synthesis gas enters three sulfuric acid towers which are connected in series for dehydration and dimethyl ether removal. The separation of the ethylene chloride is not achieved in the conventional process.

Disclosure of Invention

In view of the above, the present invention provides a system and a method for separating ethyl chloride from methyl chloride, and a system for synthesizing methyl chloride. The system for separating the chloroethane from the methyl chloride can effectively separate the chloroethane from the methyl chloride, and fully utilizes the heat energy in the separation system while separating the chloroethane.

In order to solve the technical problems, the invention adopts the following technical scheme:

in a first aspect, the present invention provides a system for separating ethyl chloride from methyl chloride, the system comprising:

the device comprises a compression device, a bidirectional heat exchange device, a chloroethane tower and a chloroethane tank;

the compression device is connected with the bidirectional heat exchange device, the bidirectional heat exchange device is connected with the chloroethane tower, the chloroethane tower kettle is connected with the chloroethane tank, and the top of the chloroethane tower is connected with the bidirectional heat exchange device.

Further, the system further comprises: a methyl chloride feed line; the inlet of the chloromethane feed pipeline is connected with the bidirectional heat exchange device, and the outlet of the chloromethane feed pipeline is communicated with the organic silicon monomer synthesis system.

Further, the system further comprises: a methyl chloride tank and a methyl chloride storage pipeline; one end of the methyl chloride storage pipeline is connected with the methyl chloride feeding pipeline, and the other end of the methane storage pipeline is connected with the methyl chloride tank.

Further, the system further comprises: a condensing unit; condensing equipment sets up on the methane storage pipeline, and be located chloromethane jar front end.

Further, the system further comprises: a tail gas absorption system; the tail gas absorption system is connected with the condensing device through a pipeline, and the tail gas absorption system absorbs methyl chloride in the non-condensable gas passing through the condensing device by adopting methanol.

In a second aspect, the present invention provides a method for separating ethyl chloride from methyl chloride by using the system as described above, wherein the method comprises:

sending methyl chloride gas containing ethyl chloride to the compression device to be compressed to obtain high-temperature high-pressure gas, wherein the high-temperature high-pressure gas firstly enters the bidirectional heat exchange device and then enters the ethyl chloride tower to be rectified, and the rectified ethyl chloride is discharged from the ethyl chloride tower kettle and collected into the ethyl chloride tank; the methyl chloride gas is discharged from the top of the ethyl chloride tower, and also enters the two-way heat exchange device after being discharged, and in the two-way heat exchange device, the high-temperature and high-pressure gas exchanges heat with the methyl chloride gas discharged from the top of the ethyl chloride tower;

and the temperature of the methyl chloride gas discharged from the top of the ethyl chloride tower is raised after heat exchange, and the methyl chloride gas is sent to a rear-end monomer synthesis system for synthesis reaction.

Further, the pressure of the high-temperature high-pressure gas is 1000kPa or more, and the temperature is 150 ℃ or more.

Further, one part of methyl chloride gas discharged from the top of the ethyl chloride tower is sent to a rear-end monomer synthesis system for synthesis reaction, and the other part is condensed and collected in a methyl chloride tank.

Further, the non-condensable gas after condensation is sent to a tail gas absorption system, the tail gas absorption system adopts methyl alcohol to absorb methyl chloride in the tail gas, the methyl alcohol dissolved with the methyl chloride after absorption is sent to a front-end methyl chloride synthesis system to be used as a raw material, and the tail gas after absorption is sent to be burned.

In a third aspect, the present invention provides a system for synthesizing methyl chloride, the system comprising:

a system for separating ethyl chloride from methyl chloride, a methyl chloride synthesis system and a rectification system as described above;

the methyl chloride synthesis system is connected with the rectification system, the rectification system is connected with the system for separating ethyl chloride from methyl chloride, and a tail gas absorption system in the system for separating ethyl chloride from methyl chloride is connected with the methyl chloride synthesis system;

the methyl chloride synthesis system is used for synthesizing hydrogen chloride and methanol to generate a crude methyl chloride product, and the rectification system is used for removing impurities in the crude methyl chloride product, wherein the impurities comprise hydrogen chloride, methanol, siloxane and dimethyl ether.

The technical scheme of the invention has the following beneficial effects:

the invention provides a system for separating chloroethane from chloromethane, which comprises: the device comprises a compression device, a bidirectional heat exchange device, a chloroethane tower and a chloroethane tank; the compression device is connected with the bidirectional heat exchange device, the bidirectional heat exchange device is connected with the chloroethane tower, the chloroethane tower kettle is connected with the chloroethane tank, and the top of the chloroethane tower is connected with the bidirectional heat exchange device.

(1) The system for separating the chloroethane from the methyl chloride provided by the invention can effectively separate the chloroethane from the methyl chloride.

(2) The invention makes full use of the heat energy in the separation system when separating the chloroethane, and exchanges heat between the compressed chloroethane-containing chloromethane gas and the chloromethane gas separated from the top of the chloroethane tower, thereby omitting a device for cooling the compressed chloroethane-containing chloromethane gas and a device for preheating the chloromethane gas separated from the top of the chloroethane tower.

(3) The pressure of the compressed methyl chloride gas is increased, meanwhile, the condensation temperature of the compressed methyl chloride gas is increased, the methyl chloride gas under normal pressure can be condensed only when the temperature reaches below-20 ℃, the compressed methyl chloride gas can be condensed by using normal-temperature cooling water, the cooling water is very easy to obtain, and the energy consumption required for condensing the methyl chloride gas is greatly reduced.

Drawings

FIG. 1 is a schematic diagram of the structure of the synthetic methyl chloride system.

Reference numerals:

the system comprises a compression device 11, a two-way heat exchange device 12, a chloroethane tower 13, a chloroethane tank 14, a chloromethane feed pipeline 15, a chloromethane tank 16, a chloromethane storage pipeline 17, a condensing device 18 and a tail gas absorption system 19;

an organosilicon monomer synthesis system 20;

a methyl chloride synthesis system 30;

a rectification system 40.

Detailed Description

For a further understanding of the invention, reference will now be made to the preferred embodiments of the invention in conjunction with the following examples, but it will be understood that the description is intended to illustrate the features and advantages of the invention further, and not to limit the invention.

The invention is further explained below with reference to fig. 1.

In a first aspect, the present invention provides a system for separating ethyl chloride from methyl chloride, the system comprising:

the system comprises a compression device 11, a two-way heat exchange device 12, a chloroethane tower 13 and a chloroethane tank 14;

the compression device 11 is connected with the bidirectional heat exchange device 12, the bidirectional heat exchange device 12 is connected with the chloroethane tower 13, the tower kettle of the chloroethane tower 13 is connected with the chloroethane tank 14, and the tower top of the chloroethane tower 13 is connected with the bidirectional heat exchange device 12.

First, the present invention provides a system for separating ethyl chloride from methyl chloride, the system comprising: the system comprises a compression device 11, a two-way heat exchange device 12, a chloroethane tower 13 and a chloroethane tank 14; in the system, methyl chloride gas containing ethyl chloride firstly enters the compression device 11, high-temperature and high-pressure gas is obtained after compression of the compression device 11, the high-temperature and high-pressure gas enters the bidirectional heat exchange device 12 connected with the compression device 11, then enters the ethyl chloride tower 13 through the bidirectional heat exchange device 12, and is rectified in the methyl chloride tower. In the rectification reaction, the ethyl chloride in the methyl chloride gas containing the ethyl chloride is separated from the bottom of the ethyl chloride tower 13 and collected in the ethyl chloride tank 14. And the methyl chloride in the methyl chloride gas containing the ethyl chloride enters the bidirectional heat exchange device 12 connected with the top of the ethyl chloride tower 13 from the top of the ethyl chloride tower.

In the system provided by the invention, because the temperature of the compressed gas is very high, the compressed gas directly enters the ethyl chloride tower 13 to damage the interior of the tower, and therefore the temperature of the compressed gas needs to be reduced. Meanwhile, the methyl chloride gas separated from the top of the ethyl chloride tower 13 needs to be sent to the rear-end organosilicon monomer synthesis system 20 through a long pipeline, and the methyl chloride gas can be cooled and condensed on the inner wall of the pipeline in the pipeline, so that the methyl chloride gas needs to be preheated to ensure that the methyl chloride gas cannot be condensed in the process of being sent to the organosilicon monomer synthesis system 20. In view of the above requirements, the system of the present invention is provided with a bidirectional heat exchange device 12, the bidirectional heat exchange device 12 is connected to the compression device 11 and the top of the ethyl chloride tower 13, compressed methyl chloride gas containing ethyl chloride and methyl chloride gas separated from the top of the ethyl chloride tower 13 continuously enter the bidirectional heat exchange device 12, and the two gases exchange heat in the bidirectional heat exchange device 12, so as to ensure that the temperature of the gas entering the ethyl chloride tower 13 is not too high, and the methyl chloride gas fed into the organosilicon monomer synthesis system 20 is preheated and does not condense in the pipeline. In conclusion, the system for separating chloroethane from chloromethane provided by the invention can effectively separate chloroethane from chloromethane. In addition, when the chloroethane is separated, the heat energy in the separation system is fully utilized, and the compressed chloromethane gas containing chloroethane and the chloromethane gas separated from the top of the chloroethane tower 13 are subjected to heat exchange, so that a device for cooling the compressed chloromethane gas containing chloroethane and a device for preheating the chloromethane gas separated from the top of the chloroethane tower 13 can be omitted, the device is simple, and the process flow is simplified.

According to some embodiments of the invention, the system for separating ethyl chloride from methyl chloride further comprises: and the inlet of the methyl chloride feeding pipeline 15 is connected with the bidirectional heat exchange device 12, and the outlet of the methyl chloride feeding pipeline 15 is communicated to the organic silicon monomer synthesis system 20. In the present invention, the methyl chloride gas preheated by the bidirectional heat exchanger 12 is sent to the organosilicon monomer synthesis system 20 through the methyl chloride feed pipe 15.

According to some embodiments of the invention, the system for separating ethyl chloride from methyl chloride further comprises: a methyl chloride tank 16 and a methyl chloride storage pipeline 17; one end of a methyl chloride storage pipeline 17 is connected with a methyl chloride feeding pipeline 15, and the other end of the methane storage pipeline is connected with a methyl chloride tank 16. In the present invention, the methyl chloride gas separated from the top of the ethyl chloride tower 13 does not enter the organosilicon monomer synthesis system 20 completely, and some of the methyl chloride gas is stored for later use. Specifically, the methyl chloride feed line 15 is connected to the methyl chloride storage line 17 as a branch, and a part of the methyl chloride gas is fed from the methyl chloride storage line 17 to the methyl chloride tank 16.

According to some embodiments of the invention, the system for separating ethyl chloride from methyl chloride further comprises: a condensing device 18; the condensing device 18 is arranged on the methane storage pipeline and is positioned at the front end of the methyl chloride tank 16. In the present invention, the methyl chloride gas described above is condensed into a liquid via the condensing device 18 before entering the methyl chloride tank 16, and then enters the methyl chloride tank 16. In the present invention, the condensing device 18 only needs to use ordinary normal temperature cooling water, because the present invention compresses methyl chloride gas containing ethyl chloride at the beginning, and the purpose of the compression is: the pressure of the compressed methyl chloride gas is increased, meanwhile, the condensation temperature of the compressed methyl chloride gas is increased, the methyl chloride gas under normal pressure can be condensed only when the temperature reaches below-20 ℃, the compressed methyl chloride gas can be condensed by using normal-temperature cooling water, the cooling water is very easy to obtain, and meanwhile, the energy consumption required for condensing the methyl chloride gas is greatly reduced.

According to some embodiments of the invention, the system for separating ethyl chloride from methyl chloride further comprises: a tail gas absorption system 19; the tail gas absorption system 19 is connected with the condensing device 18 through a pipeline, and the tail gas absorption system 19 absorbs methyl chloride in the non-condensable gas passing through the condensing device 18 by adopting methanol. In the present invention, the noncondensable gas that is not condensed by the condensing device 18 is sent to the off-gas absorption system 19. The tail gas absorption system 19 adopts methyl chloride in the methyl chloride absorption tail gas, the methyl chloride dissolved in the methyl chloride after absorption is sent to the front-end methyl chloride synthesis system 30 to be used as a raw material, and the absorbed tail gas is sent to be burned.

In a second aspect, the present invention provides a method for separating ethyl chloride from methyl chloride by using the above system, the method comprises:

sending methyl chloride gas containing ethyl chloride to the compression device 11 to be compressed to obtain high-temperature high-pressure gas, wherein the high-temperature high-pressure gas firstly enters the bidirectional heat exchange device 12 and then enters the ethyl chloride tower 13 to be rectified, and the rectified ethyl chloride is discharged from the tower kettle of the ethyl chloride tower 13 and collected into the ethyl chloride tank 14; the methyl chloride gas is discharged from the top of the ethyl chloride tower 13, the methyl chloride gas also enters the two-way heat exchange device 12 after being discharged, and the high-temperature and high-pressure gas exchanges heat with the methyl chloride gas discharged from the top of the ethyl chloride tower 13 in the two-way heat exchange device 12;

the temperature of the methyl chloride gas discharged from the top of the ethyl chloride tower 13 is raised after heat exchange, and the methyl chloride gas is sent to a rear-end monomer methyl chloride synthesis system 30 through the methyl chloride feeding pipeline 15 for synthesis reaction.

According to some embodiments of the invention, the high temperature and high pressure gas has a pressure of 1000kPa or more and a temperature of 150 ℃ or more.

According to some embodiments of the present invention, a part of the methyl chloride gas discharged from the top of the ethyl chloride tower 13 is sent to the rear-end monomer methyl chloride synthesis system 30 for synthesis reaction, and another part is condensed and collected in the methyl chloride tank 16. Specifically, a part of the methyl chloride gas discharged from the top of the ethyl chloride tower 13 is sent to a rear-end monomer methyl chloride synthesis system 30 through the methyl chloride feed pipeline 15 for synthesis reaction, and the other part is sent to the methyl chloride tank 16 through the methyl chloride storage pipeline 17.

According to some embodiments of the present invention, during the process of sending the methyl chloride gas to the methyl chloride tank 16 through the methyl chloride storage pipeline 17, the methyl chloride gas is condensed by the condensing device 18, liquid methyl chloride is collected in the methyl chloride tank 16, and the condensing device 18 uses conventional cooling water.

According to some embodiments of the present invention, the uncondensed gas that is not condensed by the condensing device 18 is sent to the tail gas absorption system 19, the tail gas absorption system 19 absorbs methyl chloride in the tail gas by using methanol, the methanol dissolved with methyl chloride after absorption is sent to the front-end methyl chloride synthesis system 30 as a raw material, and the absorbed tail gas is sent to incineration.

In a third aspect, the present invention provides a system for synthesizing methyl chloride, the system comprising:

a system for separating ethyl chloride from methyl chloride as described above, a methyl chloride synthesis system 30, and a rectification system 40;

the methyl chloride synthesis system 30 is connected with the rectification system 40, the rectification system 40 is connected with the system for separating ethyl chloride from methyl chloride, and the tail gas absorption system 19 in the system for separating ethyl chloride from methyl chloride is connected with the methyl chloride synthesis system 30;

the methyl chloride synthesis system 30 is used for synthesizing hydrogen chloride and methanol to generate a crude methyl chloride product, and the rectification system 40 is used for removing impurities in the crude methyl chloride product, wherein the impurities comprise hydrogen chloride, methanol, siloxane and dimethyl ether.

In the whole methyl chloride synthesis process, raw material methanol and raw material hydrogen chloride react in a methyl chloride synthesis system 30 to generate a methyl chloride crude product, the methyl chloride crude product enters a rectification system 40 to be rectified, most impurities such as hydrogen chloride, siloxane and dimethyl ether are removed, the methyl chloride product discharged from the rectification system 40 also comprises a small amount of ethyl chloride and a very small amount of other impurities, the ethyl chloride product enters a system for separating the ethyl chloride in the methyl chloride, the ethyl chloride in the methyl chloride product is removed through a separation system, one part of the methyl chloride obtained through the separation system is sent to an organic silicon monomer synthesis system 20, and the other part of the methyl chloride obtained is sent to a methyl chloride tank 16 to be reserved. In the process of sending to the methyl chloride tank 16, the uncondensed gas which is not condensed is sent to the tail gas absorption system 19, the methyl chloride in the tail gas is absorbed by the tail gas absorption system 19 through the methanol, and the methanol dissolved with the methyl chloride after absorption is sent to the methyl chloride synthesis system 30 as a raw material, so that the recovery and the cyclic utilization of the raw material are realized.

Unless defined otherwise, technical or scientific terms used herein shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention belongs. The use of "first," "second," and similar terms in the present application do not denote any order, quantity, or importance, but rather the terms are used to distinguish one element from another. The terms "connected" or "coupled" and the like are not restricted to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "upper", "lower", "left", "right", and the like are used merely to indicate relative positional relationships, and when the absolute position of the object being described is changed, the relative positional relationships are changed accordingly.

While the foregoing is directed to the preferred embodiment of the present invention, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined in the appended claims.