阅读说明：本技术 一种回收利用化工尾气的方法及其处理装置 (Method for recycling chemical tail gas and treatment device thereof ) 是由 张吉瑞 于 2020-04-27 设计创作，主要内容包括：本发明属于化工尾气处理的技术领域,尤其涉及一种回收利用化工尾气的方法及其处理装置,该方法包括：1)将工业尾气混合物第一预处理工序并气液分离,然后将所得气体流股i第二增压处理；2)再将气体流股i通入回收塔,塔顶采出低温气态混合物；3)将低温气态混合物第二预处理工序后,得到液体流股iii并将其进入高压液化气体产品塔；4)塔顶采出的物料进行第三预处理工序或者第四预处理工序并气液分离,得到高压液化气体产品；5)塔釜采出的液体流股v进入低压液化气体产品塔后,其塔釜采出物料为低压液化气体产品。本发明的方法能够将工业尾气中的不同组分进行有效分离,尤其能够使其中的压缩液化气体组分得到充分回收以便再利用。(The invention belongs to the technical field of chemical tail gas treatment, and particularly relates to a method for recycling chemical tail gas and a treatment device thereof, wherein the method comprises the following steps: 1) performing a first pretreatment procedure on an industrial tail gas mixture, performing gas-liquid separation, and performing second pressurization treatment on an obtained gas stream i; 2) introducing the gas stream i into a recovery tower, and extracting a low-temperature gaseous mixture from the tower top; 3) after the second pretreatment working procedure of the low-temperature gaseous mixture, obtaining a liquid stream iii and introducing the liquid stream iii into a high-pressure liquefied gas product tower; 4) carrying out a third pretreatment procedure or a fourth pretreatment procedure on the material extracted from the tower top and carrying out gas-liquid separation to obtain a high-pressure liquefied gas product; 5) after the liquid stream v extracted from the tower kettle enters the low-pressure liquefied gas product tower, the material extracted from the tower kettle is a low-pressure liquefied gas product. The method can effectively separate different components in the industrial tail gas, and particularly can fully recover the components of the compressed liquefied gas so as to be reused.)

1. A method for recycling chemical tail gas is characterized by comprising the following steps:

1) after a first pretreatment procedure is carried out on an industrial tail gas mixture to be treated, gas-liquid separation is carried out to obtain a gas stream i; then carrying out second pressurization treatment on the gas stream i;

2) introducing the gas stream i subjected to the second pressurization treatment into a recovery tower (16) for treatment, extracting a liquid stream ii from the tower kettle of the recovery tower (16), and extracting a low-temperature gaseous mixture from the tower top of the recovery tower (16);

3) after the low-temperature gaseous mixture is subjected to a second pretreatment procedure, a liquid stream iii is obtained; the liquid stream iii is then processed in a high pressure liquefied gas product column (21);

4) after the third pretreatment procedure or the fourth pretreatment procedure is carried out on the material extracted from the top of the high-pressure liquefied gas product tower (21), the high-pressure liquefied gas product is obtained through gas-liquid separation;

5) and (3) introducing the liquid stream v extracted from the tower kettle of the high-pressure liquefied gas product tower (21) into a low-pressure liquefied gas product tower (26) for treatment, wherein the material extracted from the tower kettle of the low-pressure liquefied gas product tower is the low-pressure liquefied gas product.

2. Method according to claim 1, characterized in that it comprises the following steps:

1) after a first pretreatment procedure is carried out on an industrial tail gas mixture to be treated, gas-liquid separation is carried out, and a gas stream i and a liquid stream i are obtained respectively; then carrying out second pressurization treatment on the gas stream i;

or after the industrial tail gas mixture to be treated is subjected to a first pretreatment procedure, a gas stream i is obtained, and then the gas stream i is subjected to second pressurization treatment;

preferably, the first pretreatment process comprises one or more of a demisting treatment, a temperature reduction treatment and a first pressurization treatment;

2) introducing the gas stream i subjected to the second pressurization treatment into a recovery tower (16) for treatment, extracting a liquid stream ii from the tower kettle of the recovery tower (16), and extracting a low-temperature gaseous mixture from the tower top of the recovery tower (16);

3) after the low-temperature gaseous mixture is subjected to a second pretreatment procedure, carrying out gas-liquid separation to obtain a light component impurity stream and a liquid stream iii respectively; wherein a part of the liquid stream iii is taken as reflux for the recovery column (16) and another part thereof is treated in a high pressure liquefied gas product column (21);

or after the low-temperature gaseous mixture is subjected to a second pretreatment procedure, a liquid stream iii is obtained, and then the liquid stream iii is directly fed into a high-pressure liquefied gas product tower (21) for treatment;

preferably, the second pretreatment process comprises one or more of heat exchange temperature rise treatment, third pressurization treatment and temperature reduction treatment;

4) performing a third pretreatment process on the material extracted from the top of the high-pressure liquefied gas product tower (21), and performing gas-liquid separation to obtain a gas stream ii and a liquid stream iv respectively; wherein a part of the liquid stream iv is taken as reflux for the high pressure liquefied gas product column (21) and another part thereof is taken as high pressure liquefied gas product; the gas stream ii enters the first pretreatment process for recycling; preferably, the third pretreatment process comprises a fourth pressurization treatment and a temperature reduction treatment;

or after the material extracted from the top of the high-pressure liquefied gas product tower (21) is subjected to a fourth pretreatment procedure, gas-liquid separation is carried out to respectively obtain a light component impurity stream and a liquid stream iv; wherein a portion of the liquid stream iv is refluxed to the high pressure liquefied gas product column (21), a portion is refluxed to the recovery column (16), and the remaining portion is withdrawn as high pressure liquefied gas product; preferably, the fourth pretreatment process comprises a fourth pressurization treatment and a temperature reduction treatment;

5) the liquid stream v extracted from the tower bottom of the high-pressure liquefied gas product tower (21) enters a low-pressure liquefied gas product tower (26) for treatment;

performing a fifth pretreatment process on the material extracted from the tower top of the low-pressure liquefied gas product tower (26) to respectively obtain a gas stream iii and a liquid stream vi; wherein the gas stream iii enters the first pretreatment process for recycling; the liquid stream vi is used as reflux liquid of a low-pressure liquefied gas product tower; preferably, the fifth pretreatment process comprises temperature reduction treatment and gas-liquid separation;

the material extracted from the tower kettle of the low-pressure liquefied gas product tower is the low-pressure liquefied gas product.

3. Method according to claim 1 or 2, characterized in that it comprises the following steps:

1) after a first pretreatment procedure is carried out on an industrial tail gas mixture to be treated, gas-liquid separation is carried out, and a gas stream i and a liquid stream i are obtained respectively; then carrying out second pressurization treatment on the gas stream i; the first pretreatment process comprises demisting treatment, cooling treatment and first pressurizing treatment;

2) introducing the gas stream i subjected to the second pressurization treatment into a recovery tower (16) for treatment, extracting a liquid stream ii from the tower kettle of the recovery tower (16), and extracting a low-temperature gaseous mixture from the tower top of the recovery tower (16); optionally, returning the liquid stream i and the liquid stream ii to the reaction process for recycling;

3) after the low-temperature gaseous mixture is subjected to a second pretreatment procedure, carrying out gas-liquid separation to obtain a light component impurity stream and a liquid stream iii respectively; wherein a part of the liquid stream iii is taken as reflux for the recovery column (16) and another part thereof is treated in a high pressure liquefied gas product column (21); the second pretreatment procedure comprises one or more of heat exchange heating treatment, third pressurizing treatment and temperature reduction treatment;

4) performing a third pretreatment process on the material extracted from the top of the high-pressure liquefied gas product tower (21), and performing gas-liquid separation to obtain a gas stream ii and a liquid stream iv respectively; wherein a part of the liquid stream iv is taken as reflux for the high pressure liquefied gas product column (21) and another part thereof is taken as high pressure liquefied gas product; the gas stream ii enters the first pretreatment process for recycling; the third pretreatment procedure comprises fourth pressurization treatment and cooling treatment;

5) the liquid stream v extracted from the tower bottom of the high-pressure liquefied gas product tower enters a low-pressure liquefied gas product tower (26) for treatment;

performing a fifth pretreatment process on the material extracted from the tower top of the low-pressure liquefied gas product tower (26) to respectively obtain a gas stream iii and a liquid stream vi; wherein the gas stream iii enters the first pretreatment process for recycling; the liquid stream vi is used as reflux liquid of a low-pressure liquefied gas product tower; the fifth pretreatment procedure comprises temperature reduction treatment and gas-liquid separation;

the material extracted from the tower kettle of the low-pressure liquefied gas product tower is the low-pressure liquefied gas product.

4. The method of claim 3, wherein the process conditions of step 1) comprise: the temperature after the temperature reduction treatment is 0-45 ℃; the pressure after the first pressurization treatment is 0.1-0.5 MPa; the pressure after the second pressurization treatment is 0.6-1.5 MPa;

in the step 2), the operation pressure of the recovery tower (16) is 0.1-1.5 MPa;

in the step 3), the pressure after the third pressurization treatment is 2.7MPa-10.0 MPa;

in the step 4), the operating pressure of the high-pressure liquefied gas product tower (21) is 1.5-5.0 MPa; the pressure after the fourth pressurization treatment is 3.0-8.0 MPa;

in step 5), the operating pressure of the low-pressure liquefied gas product tower (26) is 1.0-4.5 MPa.

5. Method according to claim 1 or 2, characterized in that it comprises the following steps:

1) carrying out a first pretreatment procedure on an industrial tail gas mixture to be treated to obtain a gas stream i, and then carrying out second pressurization treatment on the gas stream i; wherein the first pretreatment procedure is demisting treatment;

2) introducing the gas stream i subjected to the second pressurization treatment into a recovery tower (16) for treatment, extracting a liquid stream ii from the tower kettle of the recovery tower (16), and extracting a low-temperature gaseous mixture from the tower top of the recovery tower (16);

3) after the low-temperature gaseous mixture is subjected to a second pretreatment procedure, a liquid stream iii is obtained, and then the liquid stream iii is directly fed into a high-pressure liquefied gas product tower (21) for treatment; the second pretreatment procedure comprises one or more of heat exchange heating treatment, third pressurizing treatment and temperature reduction treatment;

4) performing a fourth pretreatment process on the material extracted from the top of the high-pressure liquefied gas product tower (21), and performing gas-liquid separation to obtain a light component impurity stream and a liquid stream iv; wherein a portion of the liquid stream iv is refluxed to the high pressure liquefied gas product column (21), a portion is refluxed to the recovery column (16), and the remaining portion is withdrawn as high pressure liquefied gas product; the fourth pretreatment procedure comprises fourth pressurization treatment and cooling treatment;

5) the liquid stream v extracted from the tower bottom of the high-pressure liquefied gas product tower enters a low-pressure liquefied gas product tower (26) for treatment;

performing a fifth pretreatment process on the material extracted from the tower top of the low-pressure liquefied gas product tower (26) to respectively obtain a gas stream iii and a liquid stream vi; wherein the gas stream iii enters the first pretreatment process for recycling; the liquid stream vi is used as reflux liquid of a low-pressure liquefied gas product tower; the fifth pretreatment procedure comprises temperature reduction treatment and gas-liquid separation;

the material extracted from the tower kettle of the low-pressure liquefied gas product tower is the low-pressure liquefied gas product.

6. The method of claim 5,

the pressure after the second pressurization treatment in the step 1) is 0.55-0.6 MPa;

in the step 2), the operation pressure of the recovery tower (16) is 0.35-0.65 MPa;

in the step 3), the pressure after the third pressurization treatment is 4.5MPa-6.5 MPa;

in the step 4), the operating pressure of the high-pressure liquefied gas product tower (21) is 3.5-6.5 MPa; the pressure after the fourth pressurization treatment is 8-13.0 MPa;

in step 5), the operating pressure of the low-pressure liquefied gas product tower (26) is 3.0-5.5 MPa.

7. The method as claimed in claim 5 or 6, wherein in the steps 3) to 5), the temperature reduction treatment is performed by an ultra-low temperature refrigeration process;

the ultra-low temperature refrigeration process comprises the following steps: the refrigerant from the refrigerant buffer tank (33) is compressed by a refrigeration compressor (30) and then enters a refrigeration heat exchanger (31) for condensation and liquefaction; the liquid refrigerant condensed and liquefied by the refrigeration heat exchanger (31) enters a refrigerant storage tank (32) for storage; when the temperature reduction treatment is carried out, liquid refrigerant extracted from the bottom of the refrigerant storage tank (32) is conveyed into the heat exchanger (X) and is subjected to vaporization heat exchange; the refrigerant after the vaporization and heat exchange returns to the refrigerant buffer tank (33) for cycle use.

8. The method according to any one of claims 1 to 7, wherein the industrial tail gas mixture to be treated comprises: compressing the liquefied gas, light component impurities and heavy component impurities;

preferably, the compressed liquefied gas comprises: one or more of hydrogen halide, hydrogen sulfide, sulfur dioxide, fluorine-containing compounds, and chlorine-containing compounds.

9. A processing apparatus for carrying out the method of any one of claims 1 to 8, comprising:

the first pretreatment module is used for carrying out impurity removal and/or pressurization pretreatment on the industrial tail gas mixture to be treated; preferably, the first preprocessing module comprises: the device comprises one or more of a demister (11) for separating and removing liquid drops, foams or solid particles entrained in an industrial tail gas mixture to be treated, a water cooler (12) for cooling the industrial tail gas mixture from which the liquid drops, foams or solid particles are removed, and a supercharger (13) for pressurizing gas;

a first compressor (15) for performing a second pressurization treatment on the gas stream treated and separated by the first pretreatment module; optionally, separating the material processed by the first pretreatment module by a separator (14);

a recovery column (16) for subjecting the gas stream compressed by the first compressor (15) to a distillation process;

the second pretreatment module is used for carrying out impurity removal and/or pressurization pretreatment on the material extracted from the top of the recovery tower (16); preferably, the second pre-treatment module comprises a first heat exchanger (17), a second compressor (18), a first condenser (19) and optionally a first separation tank (20);

the high-pressure liquefied gas product tower (21) is used for carrying out distillation treatment on the liquid stream pretreated by the second pretreatment module;

the third pretreatment module or the fourth pretreatment module is used for pretreating materials extracted from the top of the high-pressure liquefied gas product tower (21); preferably, the third pre-treatment module comprises a third compressor (22), a second condenser (23), a storage tank (24) and a second heat exchanger (25), and the fourth pre-treatment module comprises a third compressor (22), a second condenser (23) and a storage tank (24);

a low-pressure liquefied gas product tower (26) used for carrying out distillation treatment on the liquid stream extracted from the tower bottom of the high-pressure liquefied gas product tower (21);

the fifth pretreatment module is used for pretreating materials extracted from the tower top of the low-pressure liquefied gas product tower (26); preferably, the fifth pre-treatment module comprises a third condenser (27) and a second separation tank (28);

an inlet for an industrial tail gas mixture is arranged in the first pretreatment module, and the first pretreatment module is connected with the recovery tower (16) through the first compressor (15); the recovery tower (16) is connected with the high-pressure liquefied gas product tower (21) through a second pretreatment module;

connecting the high-pressure liquefied gas product column (21) with the low-pressure liquefied gas product column (26) by a third pre-treatment module or connecting the high-pressure liquefied gas product column (21) with the low-pressure liquefied gas product column (26) by a fourth pre-treatment module;

the low pressure liquefied gas product column (26) is also connected to a fifth pre-treatment module.

10. The processing apparatus according to claim 9,

in the first pretreatment module, an inlet of the industrial tail gas mixture is arranged at the lower part of the demister (11); the outlet of the demister (11) is directly connected with the first compressor (15), or the outlet of the demister (11) is connected with the first compressor (15) sequentially through the water cooler (12), the supercharger (13) and the separator (14); and/or

In the second pretreatment module, the material extracted from the top of the recovery tower (16) enters the first heat exchanger (17) for heating, then enters the second compressor (18) for pressurization, and the outlet gas of the second compressor (18) enters the first heat exchanger (17) again for heat exchange and cooling, and then enters the first condenser (19); feeding the material condensed by the first condenser (19) into the first separation tank (20), wherein non-condensable gas is extracted from the top of the first separation tank (20), a liquid part flows out from the bottom of the first separation tank (20), one part of the liquid part enters the top reflux of the recovery tower (16), and the other part of the liquid part enters the high-pressure liquefied gas tower (21); and/or

In the third pretreatment module, the top outlet of the high-pressure liquefied gas product tower (21) is connected in parallel with the second condenser (23) and the second heat exchanger (25) through the third compressor (22), and the outlet after the parallel connection is connected with the storage tank (24); and/or

In the fourth pretreatment module, the top outlet of the high-pressure liquefied gas product tower (21) is connected with the second condenser (23) through the third compressor (22), and the second condenser (23) is connected with the storage tank (24); and/or

In the fifth pretreatment module, the top outlet of the low-pressure liquefied gas product tower (26) is connected to the second separation tank (28) via the third condenser (27).

Technical Field

The invention belongs to the technical field of chemical tail gas treatment, and particularly relates to a method for recycling chemical tail gas and a treatment device thereof.

Background

With the rapid development of national economy and the gradual improvement of national requirements on environmental protection, industrial tail gas waste generated in the chemical production process becomes an important factor for restricting the development of enterprises. The shortage of resources and the environmental protection are more and more emphasized by the governments and enterprises at all levels of the country, and the resource saving and the environmental protection become important factors and preconditions for the continuous, rapid and healthy development of the chemical industry and the improvement of the market competitiveness. With the progress of environmental protection technology, the treatment technology of industrial tail gas generated in the chemical production process gradually changes from harmless treatment to cyclic utilization of chemical resources. The recycling of the tail gas waste becomes a development direction of industrial tail gas recycling.

Patent document CN208742269U discloses a hydrogen sulfide tail gas efficient recovery treatment tank, which improves the alkali absorption efficiency of the tail gas hydrogen sulfide, but still belongs to a harmless treatment technology, and cannot realize the recovery and utilization of hydrogen sulfide tail gas resources.

Patent document CN107983090A discloses a comprehensive treatment process for acyl chloride tail gas, which recycles sulfur dioxide in the acyl chloride tail gas; however, for another important hydrogen chloride gas, acid absorption is adopted to form waste acid substances, and the problem of tail gas recycling is not completely solved.

Therefore, it is important to develop a method for recycling the exhaust gas to a sufficient resource.

Disclosure of Invention

The invention aims to provide a method for recycling chemical tail gas and a processing device thereof, aiming at solving the problem that the existing chemical tail gas processing can not achieve resource recycling, which can effectively separate different components in the industrial tail gas, and particularly can fully recycle the compressed liquefied gas components in the industrial tail gas for recycling.

In order to achieve the above purpose, the invention provides the following technical scheme:

on the one hand, the method for recycling the chemical tail gas comprises the following steps:

1) after a first pretreatment procedure is carried out on an industrial tail gas mixture to be treated, gas-liquid separation is carried out to obtain a gas stream i; then carrying out second pressurization treatment on the gas stream i;

2) introducing the gas stream i subjected to the second pressurization treatment into a recovery tower 16 for treatment, extracting a liquid stream ii (for example, containing heavy components such as reaction mother liquor, moisture and the like) at the tower bottom of the recovery tower 16, and extracting a low-temperature gaseous mixture at the tower top of the recovery tower 16;

3) after the low-temperature gaseous mixture is subjected to a second pretreatment procedure, a liquid stream iii is obtained; the liquid stream iii is then processed in a high pressure liquefied gas product column 21;

4) after the third pretreatment procedure or the fourth pretreatment procedure is carried out on the material extracted from the tower top of the high-pressure liquefied gas product tower 21, the high-pressure liquefied gas product is obtained through gas-liquid separation;

5) and (3) the liquid stream v extracted from the tower bottom of the high-pressure liquefied gas product tower 21 enters a low-pressure liquefied gas product tower 26 for treatment, and the material extracted from the tower bottom of the low-pressure liquefied gas product tower is the low-pressure liquefied gas product.

Wherein the first pretreatment process may include one or more of a defogging process, a cooling process and a first pressurization process; the second pretreatment process may include one or more of heat exchange temperature rise treatment, third pressurization treatment and temperature reduction treatment; the third pretreatment procedure comprises fourth pressurization treatment and cooling treatment; the fourth pretreatment procedure comprises fourth pressurization treatment and cooling treatment; the fifth pretreatment process comprises temperature reduction treatment and gas-liquid separation.

In the method provided by the invention, the industrial tail gas mixture to be treated contains two or more main substances and a plurality of impurity components which need to be recovered; wherein the main substance is a compressed liquefied gas.

The compressed liquefied gas is divided into: low-pressure liquefied gas (critical temperature tc is more than 70 ℃) and high-pressure liquefied gas (-tc is more than 10 ℃ and less than 70 ℃). The industrial tail gas contains various impurity components besides the compressed liquefied gas. Wherein, the critical temperature tc < -10 ℃ is called light component impurity and is basically non-condensable gas generated by reaction or air leaked in the reaction process; another type is liquid volatiles, referred to as heavy ends impurities, that are volatilized into the tail gas. The heavy component impurities are liquid at normal temperature and normal pressure, and are basically liquid products, liquid byproducts, liquid reactants which are not completely reacted, solvents, water and the like which are generated by the reaction and are volatilized into liquid volatile matters in gas.

According to the method provided by the invention, in some examples, the method comprises the following steps:

1) after a first pretreatment procedure is carried out on an industrial tail gas mixture to be treated, gas-liquid separation is carried out, and a gas stream i and a liquid stream i (containing heavy components such as reaction mother liquor, moisture and the like) are respectively obtained; then carrying out second pressurization treatment on the gas stream i;

or after the industrial tail gas mixture to be treated is subjected to a first pretreatment procedure, a gas stream i is obtained, and then the gas stream i is subjected to second pressurization treatment;

preferably, the first pretreatment process comprises one or more of a demisting treatment, a temperature reduction treatment and a first pressurization treatment;

2) introducing the gas stream i subjected to the second pressurization treatment into a recovery tower 16 for treatment, extracting a liquid stream ii (for example, containing heavy components such as reaction mother liquor, moisture and the like) at the tower bottom of the recovery tower 16, and extracting a low-temperature gaseous mixture at the tower top of the recovery tower 16;

3) after the low-temperature gaseous mixture is subjected to a second pretreatment procedure, carrying out gas-liquid separation to obtain a light component impurity stream and a liquid stream iii respectively; wherein a part of the liquid stream iii is taken as reflux for the recovery column 16 and another part thereof is processed into a high pressure liquefied gas product column 21;

or after the low-temperature gaseous mixture is subjected to a second pretreatment procedure, a liquid stream iii is obtained, and then the liquid stream iii directly enters the high-pressure liquefied gas product tower 21 for treatment;

preferably, the second pretreatment process comprises one or more of heat exchange temperature rise treatment, third pressurization treatment and temperature reduction treatment;

4) performing a third pretreatment process on the material extracted from the top of the high-pressure liquefied gas product tower 21, and performing gas-liquid separation to obtain a gas stream ii and a liquid stream iv; wherein a part of the liquid stream iv is taken as reflux liquid for the high pressure liquefied gas product column 21 and another part thereof is taken as high pressure liquefied gas product; the gas stream ii enters the first pretreatment process for recycling; preferably, the third pretreatment process comprises a fourth pressurization treatment and a temperature reduction treatment;

or, after the fourth pretreatment process is performed on the material extracted from the top of the high-pressure liquefied gas product tower 21, performing gas-liquid separation to obtain a light component impurity stream and a liquid stream iv; wherein a portion of the liquid stream iv is refluxed to the high pressure liquefied gas product column 21, a portion is refluxed to the recovery column 16, and the remaining portion is withdrawn as a high pressure liquefied gas product (e.g., hydrogen chloride product); preferably, the fourth pretreatment process comprises a fourth pressurization treatment and a temperature reduction treatment;

5) the liquid stream v extracted from the tower bottom of the high-pressure liquefied gas product tower 21 enters a low-pressure liquefied gas product tower 26 for treatment;

performing a fifth pretreatment process on the material extracted from the tower top of the low-pressure liquefied gas product tower 26 to obtain a gas stream iii and a liquid stream vi respectively; wherein the gas stream iii enters the first pretreatment process for recycling; the liquid stream vi is used as reflux liquid of a low-pressure liquefied gas product tower; preferably, the fifth pretreatment process comprises temperature reduction treatment and gas-liquid separation;

the material extracted from the tower kettle of the low-pressure liquefied gas product tower is the low-pressure liquefied gas product.

In some embodiments, the method comprises the steps of:

1) after a first pretreatment procedure is carried out on an industrial tail gas mixture to be treated, gas-liquid separation is carried out, and a gas stream i and a liquid stream i (containing heavy components such as reaction mother liquor, moisture and the like) are respectively obtained; then carrying out second pressurization treatment on the gas stream i; the first pretreatment process comprises demisting treatment, cooling treatment and first pressurizing treatment;

2) introducing the gas stream i subjected to the second pressurization treatment into a recovery tower 16 for treatment, extracting a liquid stream ii (containing heavy components such as reaction mother liquor, moisture and the like) at the tower bottom of the recovery tower (16), and extracting a low-temperature gaseous mixture at the tower top of the recovery tower 16; optionally, returning the liquid stream i and the liquid stream ii to the reaction process for recycling;

3) after the low-temperature gaseous mixture is subjected to a second pretreatment procedure, carrying out gas-liquid separation to obtain a light component impurity stream and a liquid stream iii respectively; wherein a part of the liquid stream iii is taken as reflux for the recovery column 16 and another part thereof is processed into a high pressure liquefied gas product column 21; the second pretreatment procedure comprises one or more of heat exchange heating treatment, third pressurizing treatment and temperature reduction treatment;

4) performing a third pretreatment process on the material extracted from the top of the high-pressure liquefied gas product tower 21, and performing gas-liquid separation to obtain a gas stream ii and a liquid stream iv; wherein a part of the liquid stream iv is taken as reflux liquid for the high pressure liquefied gas product column 21 and another part thereof is taken as high pressure liquefied gas product; the gas stream ii enters the first pretreatment process for recycling; the third pretreatment procedure comprises fourth pressurization treatment and cooling treatment;

5) the liquid stream v extracted from the tower bottom of the high-pressure liquefied gas product tower enters a low-pressure liquefied gas product tower 26 for treatment;

performing a fifth pretreatment process on the material extracted from the tower top of the low-pressure liquefied gas product tower 26 to obtain a gas stream iii and a liquid stream vi respectively; wherein the gas stream iii enters the first pretreatment process for recycling; the liquid stream vi is used as reflux liquid of a low-pressure liquefied gas product tower; the fifth pretreatment procedure comprises temperature reduction treatment and gas-liquid separation;

the material extracted from the tower kettle of the low-pressure liquefied gas product tower is the low-pressure liquefied gas product.

In some examples, the process conditions of step 1) include: the temperature after the temperature reduction treatment is 0-45 ℃, and preferably 20-25 ℃; the pressure after the first pressurization treatment is 0.1-0.5 MPa; the pressure after the second pressurization treatment is 0.6-1.5 MPa;

in some examples, in step 2), the operating pressure of the recovery column 16 is from 0.1 to 1.5 MPa;

in some examples, in step 3), the pressure after the third pressurization treatment is 2.7MPa to 10.0 MPa;

in some examples, in step 4), the operating pressure of the high pressure liquefied gas product column 21 is 1.5 to 5.0 MPa;

in the step 4), the pressure after the fourth pressurization treatment is 3.0-8.0 MPa;

in some examples, the operating pressure of the low pressure liquefied gas product column 26 in step 5) is 1.0-4.5 MPa.

In some embodiments, the method comprises the steps of:

1) carrying out a first pretreatment procedure on an industrial tail gas mixture to be treated to obtain a gas stream i, and then carrying out second pressurization treatment on the gas stream i; wherein the first pretreatment procedure is demisting treatment;

2) introducing the gas stream i subjected to the second pressurization treatment into a recovery tower 16 for treatment, extracting a liquid stream ii (for example, containing heavy components such as reaction mother liquor, moisture and the like) at the tower bottom of the recovery tower 16, and extracting a low-temperature gaseous mixture at the tower top of the recovery tower 16;

3) after the low-temperature gaseous mixture is subjected to a second pretreatment procedure, a liquid stream iii is obtained, and then the liquid stream iii is directly fed into a high-pressure liquefied gas product tower 21 for treatment; the second pretreatment procedure comprises one or more of heat exchange heating treatment, third pressurizing treatment and temperature reduction treatment;

4) performing a fourth pretreatment process on the material extracted from the top of the high-pressure liquefied gas product tower 21, and performing gas-liquid separation to obtain a light component impurity stream and a liquid stream iv; wherein a portion of the liquid stream iv is refluxed to the high pressure liquefied gas product column 21, a portion is refluxed to the recovery column 16, and the remaining portion is withdrawn as a high pressure liquefied gas product (e.g., hydrogen chloride product); the fourth pretreatment procedure comprises fourth pressurization treatment and cooling treatment;

5) the liquid stream v extracted from the tower bottom of the high-pressure liquefied gas product tower enters a low-pressure liquefied gas product tower 26 for treatment;

performing a fifth pretreatment process on the material extracted from the tower top of the low-pressure liquefied gas product tower 26 to obtain a gas stream iii and a liquid stream vi respectively; wherein the gas stream iii enters the first pretreatment process for recycling; the liquid stream vi is used as reflux liquid of a low-pressure liquefied gas product tower; the fifth pretreatment procedure comprises temperature reduction treatment and gas-liquid separation;

the material extracted from the tower kettle of the low-pressure liquefied gas product tower is the low-pressure liquefied gas product.

In some examples, the pressure after the second pressurization treatment in step 1) is 0.55-0.6 MPa;

in some examples, in step 2), the operating pressure of the recovery column 16 is from 0.35 to 0.65 MPa;

in some examples, in step 3), the pressure after the third pressurization treatment is 4.5MPa to 6.5 MPa;

in some examples, in step 4), the operating pressure of the high pressure liquefied gas product column 21 is 3.5 to 6.5 MPa;

step 4), the pressure after the fourth pressurization treatment is 8-13.0 MPa;

in some examples, the operating pressure of the low pressure liquefied gas product column 26 in step 5) is 3.0-5.5 MPa.

According to the method provided by the invention, preferably, in the steps 3) to 5), the temperature reduction treatment is performed through an ultralow temperature refrigeration process;

the ultra-low temperature refrigeration process comprises the following steps: the refrigerant (for example, hydrogen chloride) from the refrigerant buffer tank 33 is compressed by the refrigeration compressor 30, and then enters the refrigeration heat exchanger 31 for condensation and liquefaction; the refrigerant of the refrigeration heat exchanger 31 may be, for example, normal-temperature circulating water or low-temperature chilled water; the liquid refrigerant condensed and liquefied by the refrigeration heat exchanger 31 enters a refrigerant storage tank 32 for storage; when the temperature reduction treatment is carried out, liquid refrigerant extracted from the bottom of the refrigerant storage tank 32 is conveyed to a heat exchanger X (for example, the second condenser 23 and the third condenser 27 are used as the heat exchanger X here), and is subjected to vaporization heat exchange; in the heat exchanger, the liquid refrigerant is vaporized and expanded to be used as a refrigerant of the heat exchanger, and heat exchange is carried out between the refrigerant and a heating medium in the heat exchanger; the refrigerant after the vaporization heat exchange returns to the refrigerant buffer tank 33 for cycle use.

According to the method provided by the invention, in some examples, the industrial tail gas mixture to be treated comprises: compressing the liquefied gas, light component impurities and heavy component impurities;

preferably, the compressed liquefied gas comprises: one or more of hydrogen halide (e.g., hydrogen chloride, hydrogen fluoride, hydrogen bromide), hydrogen sulfide, sulfur dioxide, fluorine-containing compound (e.g., monofluorodichloromethane, difluorochloromethane, difluorodichloromethane, difluorobromochloromethane, chlorotrifluoroethane, tetrafluorodichloroethane, pentafluorochloroethane, octafluorocyclobutane, hexafluoropropylene, or sulfuryl fluoride), and chlorine-containing compound (e.g., dichlorosilane, trichlorosilane, silicon tetrachloride, chloromethane, chloroethane, bromomethane, vinyl bromide, or vinyl chloride).

For example, the compressed liquefied gas includes: hydrogen halides (e.g., hydrogen chloride, hydrogen fluoride, hydrogen bromide), hydrogen sulfide, sulfur dioxide, and fluorine-containing compounds (e.g., monofluorodichloromethane, difluorochloromethane, difluorodichloromethane, difluorobromochloromethane, chlorotrifluoroethane, tetrafluorodichloroethane, pentafluorochloroethane, octafluorocyclobutane, hexafluoropropylene, or sulfuryl fluoride).

For example, the compressed liquefied gas includes: hydrogen halides (e.g., hydrogen chloride, hydrogen fluoride, hydrogen bromide), hydrogen sulfide, sulfur dioxide, and chlorine-containing compounds (e.g., dichlorosilane, trichlorosilane, silicon tetrachloride, methyl chloride, ethyl chloride, methyl bromide, vinyl bromide, or vinyl chloride).

For example, the compressed liquefied gas includes: hydrogen halides (e.g., hydrogen chloride, hydrogen fluoride, hydrogen bromide), hydrogen sulfide, sulfur dioxide, fluorine-containing compounds (e.g., monofluorodichloromethane, difluorochloromethane, difluorodichloromethane, difluorobromochloromethane, chlorotrifluoroethane, tetrafluorodichloroethane, pentafluorochloroethane, octafluorocyclobutane, hexafluoropropylene, or sulfuryl fluoride), and chlorine-containing compounds (e.g., dichlorosilane, trichlorosilane, silicon tetrachloride, chloromethane, chloroethane, bromomethane, vinyl bromide, or vinyl chloride).

In another aspect, the present invention also provides a processing apparatus for implementing the method described above, comprising:

the first pretreatment module is used for carrying out impurity removal and/or pressurization pretreatment on the industrial tail gas mixture to be treated; preferably, the first preprocessing module comprises: the system comprises a demister 11 for separating and removing liquid drops, foams or solid particles carried in an industrial tail gas mixture to be treated, a water cooler 12 for cooling the industrial tail gas mixture from which the liquid drops, foams or solid particles are removed, and one or more superchargers 13 for supercharging gas;

the first compressor 15 is used for performing second pressurization treatment on the gas stream obtained by the treatment and separation of the first pretreatment module; optionally, separating the material processed by the first pretreatment module by a separator 14;

a recovery column 16 for subjecting the gas stream compressed by the first compressor 15 to a distillation process;

the second pretreatment module is used for carrying out impurity removal and/or pressurization pretreatment on the material extracted from the top of the recovery tower 16; preferably, the second pre-treatment module comprises a first heat exchanger 17, a second compressor 18, a first condenser 19 and optionally a first separation tank 20;

the high-pressure liquefied gas product tower 21 is used for carrying out distillation treatment on the liquid stream pretreated by the second pretreatment module;

the third pretreatment module or the fourth pretreatment module is used for pretreating materials extracted from the top of the high-pressure liquefied gas product tower 21; preferably, the third pre-treatment module comprises a third compressor 22, a second condenser 23, an accumulator 24 and a second heat exchanger 25, and the fourth pre-treatment module comprises a third compressor 22, a second condenser 23 and an accumulator 24;

a low-pressure liquefied gas product tower 26 for performing distillation treatment on the liquid stream extracted from the tower bottom of the high-pressure liquefied gas product tower 21;

a fifth pre-treatment module, configured to pre-treat the material extracted from the top of the low-pressure liquefied gas product tower 26; preferably, the fifth pre-treatment module comprises a third condenser 27 and a second separation tank 28;

an inlet for the industrial tail gas mixture is arranged in the first pretreatment module, and the first pretreatment module is connected with the recovery tower 16 through the first compressor 15; the recovery tower 16 is connected with the high-pressure liquefied gas product tower 21 through a second pretreatment module;

connecting the high pressure liquefied gas product column 21 with the low pressure liquefied gas product column 26 by a third pre-treatment module or connecting the high pressure liquefied gas product column 21 with the low pressure liquefied gas product column 26 by a fourth pre-treatment module;

the low pressure liquefied gas product column 26 is also connected to a fifth pre-treatment module.

According to the processing device of the invention, in some examples, in the first pretreatment module, the inlet of the industrial tail gas mixture is arranged at the lower part of the demister 11; the outlet of the demister 11 is directly connected with the first compressor 15, or the outlet of the demister 11 is connected with the first compressor 15 sequentially through the water cooler 12, the supercharger 13 and the separator 14 (i.e., the outlet of the demister 11 is connected with the water cooler 12, the water cooler 12 is connected with the supercharger 13, the supercharger 13 is connected with the separator 14, and the separator 14 is connected with the first compressor 15);

in the second pretreatment module, the material extracted from the top of the recovery tower 16 enters the first heat exchanger 17 for heating, and then enters the second compressor 18 for pressurization, and the outlet gas of the second compressor 18 enters the first heat exchanger 17 again for heat exchange and cooling, and then enters the first condenser 19; the material condensed by the first condenser 19 enters the first separation tank 20, wherein non-condensable gas is extracted from the top of the first separation tank 20, a liquid part flows out from the bottom of the first separation tank 20, one part of the liquid part enters the top reflux of the recovery tower 16, and the other part of the liquid part enters the high-pressure liquefied gas tower 21;

in the third pretreatment module, the outlet of the top of the high-pressure liquefied gas product tower 21 is connected in parallel with the second condenser 23 and the second heat exchanger 25 through the third compressor 22, and the outlet after the parallel connection is connected with the storage tank 24;

in the fourth pretreatment module, the outlet of the top of the high-pressure liquefied gas product tower 21 is connected with the second condenser 23 through the third compressor 22, and the second condenser 23 is connected with the storage tank 24;

in the fifth pre-treatment module, the outlet of the low-pressure liquefied gas product tower 26 is connected to the second separation tank 28 via the third condenser 27.

The cold sources of the second condenser 23 and the third condenser 27 can be provided by an ultra-low temperature refrigeration process. Wherein, the used device of ultra-low temperature refrigeration technology includes: a refrigeration compressor 30, a refrigeration heat exchanger 31, a refrigerant storage tank 32, a heat exchanger X (for example, the second condenser 23 and the third condenser 27 are the heat exchanger X here), and a refrigerant buffer tank 33; the connection relationship of the components may be, for example: the outlet of the refrigerant buffer tank 33 is connected with the inlet of the refrigeration compressor 30, the outlet of the refrigeration compressor 30 is connected with the inlet of the refrigeration heat exchanger 31, the outlet of the refrigeration heat exchanger 31 is connected with the inlet of the refrigerant storage tank 32, the outlet of the refrigerant storage tank 32 is connected with the cold source inlet of the heat exchanger X, and the cold source outlet of the heat exchanger X is connected with the inlet of the refrigerant buffer tank 33.

Compared with the prior art, the technical scheme of the invention has the beneficial effects that:

the method provided by the invention realizes the conversion of the treatment technology of the industrial tail gas generated in the chemical production process from harmless treatment to chemical recycling, can effectively separate different components in the industrial tail gas, and particularly can separate the compressed liquefied gas in the industrial tail gas under the condition of not additionally generating waste, thereby thoroughly solving the problem of recycling the tail gas.

Drawings

Fig. 1 is a schematic flow chart of a method for recycling chemical tail gas according to an embodiment.

Fig. 2 is a schematic flow chart of a method for recycling chemical tail gas according to another embodiment.

Fig. 3 is a flow chart of an implementation process of cooling treatment of each heat exchanger in the flow chart of fig. 2.

The reference numerals in the above figures are explained as follows:

11-demister (e.g., intermittent blowdown), 12-water cooler, 13-booster, 14-separator (e.g., intermittent blowdown), 15-first compressor, 16-recovery column, 17-first heat exchanger, 18-second compressor, 19-first condenser, 20-first separation tank, 21-high pressure liquefied gas product column, 22-third compressor, 23-second condenser, 24-storage tank (e.g., intermittent blowdown), 25-second heat exchanger, 26-low pressure liquefied gas product column, 27-third condenser, 28-second separation tank, 29-reboiler; 30-refrigeration compressor, 31-refrigeration heat exchanger, 32-refrigerant storage tank, 33-refrigerant buffer tank and X-various heat exchangers (or condensers).

The method comprises the following steps of firstly, preparing an industrial tail gas mixture to be treated, secondly, preparing a heavy component impurity stream, thirdly, preparing a light component impurity stream, fourthly, preparing a high-pressure liquefied gas product and fifthly, preparing a low-pressure liquefied gas product.

Detailed Description

In order to better understand the technical solution of the present invention, the following examples are further provided to illustrate the present invention, but the present invention is not limited to the following examples.

In the method provided by the invention, the industrial tail gas mixture to be treated contains two or more main substances and a plurality of impurity components which need to be recovered; wherein, the main substances are low-pressure liquefied gas (critical temperature tc is more than 70 ℃) and high-pressure liquefied gas (tc is more than 10 ℃ and less than or equal to 70 ℃); the impurity components are mainly light component impurities, the critical temperature tc of the impurities is less than-10 ℃, and the impurities are basically non-condensable gas generated by reaction or air leaked in the reaction process; and heavy component impurities, which are volatile matters which are liquid at normal temperature and are volatilized into the tail gas, can include liquid products, liquid by-products, liquid reactants which are not completely reacted, solvents, water and other liquid volatile matters which are volatilized into gas.

For such industrial exhaust gas mixture, the treatment method and the device thereof adopted in the present application can refer to fig. 1, for example, and the process flow can be:

the industrial tail gas mixture discharged from the reactor or a separation device after the reactor is subjected to a first pretreatment procedure, namely, the industrial tail gas mixture is treated by a demister 11, and liquid drops, foams or solid particles possibly entrained in the industrial tail gas mixture are separated and removed; the material without liquid or solid impurities enters a water cooler 12 for cooling treatment, the temperature of the material is reduced to normal temperature (for example, 25 ℃), then the material at normal temperature is introduced into a supercharger 13 (for example, a turbine or a circulation pump) for first supercharging treatment, and the material at normal temperature under normal pressure or slight negative pressure is supercharged to 0.1-0.5 Mpa. The pressurized material enters from the middle part or the upper part of the separator 14 and is subjected to gas-liquid separation, and a liquid stream i containing a small amount of heavy components can be discharged from the bottom of the separator 14 periodically and intermittently; and introducing a gas stream i continuously discharged from the top of the separator 14 into the first compressor 15 for second pressurization treatment, and pressurizing the gas stream i to 0.6-1.5 MPa. The pressurized gas stream i enters the recovery tower 16 from the bottom or the lower part of the recovery tower 16, wherein the recovery tower 16 can be a rectifying tower, and the operating pressure of the recovery tower 16 is 0.1-1.5 MPa; a liquid stream ii containing heavy components such as reaction mother liquor, water and the like is extracted from the tower bottom of the recovery tower 16, and optionally, the obtained liquid stream i and the obtained liquid stream ii can be returned to the reaction process for recycling; while a low temperature gaseous mixture is withdrawn overhead from the recovery column 16. The low-temperature gaseous mixture is subjected to a second pretreatment process, namely, the low-temperature gaseous mixture enters a first heat exchanger 17, exchanges heat with compressed gas to raise the temperature, enters a second compressor 18 to compress the compressed gas to 2.7-10.0 MPa, the compressed gas enters the first heat exchanger 17 again, exchanges heat with the low-temperature gaseous mixture extracted from the top of the recovery tower 16 to lower the temperature, and then enters a first condenser 19 (for example, a tubular condenser capable of indirect heat exchange or other condensers, wherein a cold source is normal-temperature circulating water or chilled water, the water temperature can be-37 ℃ to 17 ℃) to condense the compressed gas, the condensed material is completely introduced into a first separation tank 20 to be subjected to gas-liquid separation, and a light-component impurity stream is discharged from the top of the first separation tank 20 and contains a large amount of high-pressure liquefied gas, and can be used as a low-end industrial product; and a liquid stream iii is produced at the bottom of the first separation tank 20, a part of which is used as reflux liquid for the recovery column 16, and the other part of which enters a high-pressure liquefied gas product column 21 for treatment. The high pressure liquefied gas product column 21 may be a modified heat pump rectification column with an operating pressure of 1.5-5.0 Mpa; the gas extracted from the top of the high-pressure liquefied gas product tower 21 is subjected to a third pretreatment process, namely, the gas enters a third compressor 22 and is pressurized to 3.0-8.0MPa, and then enters a second heat exchanger 25 and a second condenser 23 (the cold source of the gas is normal-temperature circulating water or chilled water, and the water temperature can be-37 ℃ to 17 ℃) respectively to be cooled and liquefied, the liquefied material enters a storage tank 24 for gas-liquid separation, a part of a liquid stream iv extracted from the bottom of the storage tank 24 is taken as a reflux liquid of the high-pressure liquefied gas product tower 21, and the other part of the liquid stream is extracted as a high-pressure liquefied gas product, and the gas enters a filling process and is directly filled in a product packaging container; a gas stream ii produced from the top of the storage tank 24 enters the first pretreatment process for recycling; the second heat exchanger 25 is simultaneously a kettle reboiler of the high pressure liquefied gas product column 21.

If the industrial tail gas to be treated contains several high-pressure liquefied gases, it can be further separated into single components by using the same improved heat pump rectifying tower. The top of the high pressure liquefied gas product tower 21 will produce liquefied gas with high boiling point, while the bottom will produce liquefied gas with low boiling point. For example, the liquid stream v withdrawn from the bottom of the high pressure liquefied gas product column 21 enters a low pressure liquefied gas product column 26, which may be a rectification column, operating at a pressure of 1.0-4.5 MPa; the gas extracted from the top of the low-pressure liquefied gas product tower 26 is subjected to a fifth pretreatment process, that is, the gas enters a third condenser 27 (a cold source thereof is normal-temperature circulating water or chilled water, and the water temperature can be-37 ℃ to 17 ℃) to be condensed, the condensed material enters a second separation tank 28 to be separated, a gas stream iii extracted from the top of the second separation tank 28 is returned to the demister 11 to be recycled, and a liquid stream vi extracted from the bottom of the second separation tank 28 is a reflux liquid of the low-pressure liquefied gas product tower 26. The liquid extracted from the tower bottom of the low-pressure liquefied gas product tower 26 is the low-pressure liquefied gas product, and is directly filled in the product package in the filling procedure. The reboiler 29 used in the bottom of the low pressure liquefied gas product column 26 may be heated with hot water, a guided oil or low pressure steam. If the industrial tail gas contains a plurality of low-pressure liquefied gases, the industrial tail gas can be separated by a modified heat pump rectifying tower which is the same as the high-pressure liquefied gas product tower 21, and then purified by the rectifying tower respectively. The tower top extracts compressed gas with high boiling point, and the tower kettle extracts compressed gas with low boiling point.

< sources of raw materials >

1# industrial tail gas mixture to be treated, which mainly comprises the following components:

hydrogen chloride, sulfur dioxide, trichloroethane, light component impurities and heavy component impurities;

2# industrial tail gas mixture to be treated, which mainly comprises the following components:

hydrogen chloride, hydrogen sulfide, light component impurities and heavy component impurities;

3# industrial tail gas mixture to be treated, which mainly comprises the following components:

hydrogen chloride, hydrogen bromide, dichloromethane, monobromo-chloromethane, dibromomethane, light component impurities and heavy component impurities; wherein the content of light component impurities (such as hydrogen, oxygen, nitrogen and other permanent gases) exceeds 10%.

< measuring method >

The method for measuring the component content in each stream adopts gas chromatography.

Example 1:

recovering, separating and purifying from the industrial tail gas mixture to be treated No. 1: hydrogen chloride and sulfur dioxide, wherein the hydrogen chloride is a high-pressure liquefied gas, and the sulfur dioxide is a low-pressure liquefied gas.

The device for implementing the method for recycling the chemical tail gas is shown in figure 1, and the specific process flow of the method is as follows:

containing light component impurities (N)₂、O₂) 1# industrial tail gas mixture to be treated of mother liquid (namely heavy component impurity and water) impurity, hydrogen chloride (high-pressure liquefied gas product) and sulfur dioxide (low-pressure liquefied gas product) is treated by a demister 11, liquid, foam or solid particles which are possibly carried are removed, the mixture enters a water cooler 12 to be cooled to the normal temperature of 25 ℃, and then the mixture enters a water increasing cooler 12 to be cooledThe press 13 is pressurized to 0.2 MPa. After the pressurized gas is treated by the separator 14, a heavy component liquid stream i (i.e., a heavy component impurity stream @) is extracted from the bottom of the pressurized gas and recovered as mother liquor, and a gas stream i extracted from the top of the pressurized gas enters the first compressor 15 to be subjected to second pressurization treatment and pressurized to 0.6 MPa. The compressed gas stream i is introduced directly into the lower part of the recovery column 16 and treated, at an operating pressure of 0.6 MPa.

And a heavy component liquid stream ii separated from the bottom of the recovery tower 16 is a liquid mixture containing mother liquor impurities (namely, a heavy component impurity stream II) which is recovered as mother liquor and returns to the reaction process with the obtained heavy component-containing liquid stream i for utilization. The low-temperature gaseous mixture is extracted from the top of the recovery tower 16, passes through the first heat exchanger 17, is subjected to heat exchange with compressed gas, is heated and enters the second compressor 18 for pressurization, is compressed to 4.0MPa, the compressed gas is output from the outlet of the second compressor 18 and enters the first heat exchanger 17 again for heat exchange and cooling, and the cooled material enters the first condenser 19 (cooled by water at the temperature of minus 30 ℃) for condensation and liquefaction. The condensed liquid enters a first separation tank 20 for gas-liquid separation, a low-concentration hydrogen chloride byproduct containing light component impurities (namely, a light component impurity stream (c)) is extracted from the top of the first separation tank, and a part of a liquid stream iii extracted from the bottom of the first separation tank flows back to a recovery tower 16, and the other part of the liquid stream enters a high-pressure liquefied gas product tower 21 (the tower is an improved heat pump rectifying tower, and the operating pressure of the tower is 3.0MPa) for treatment.

The gas extracted from the top of the high-pressure liquefied gas product tower 21 is compressed to 7.0MPa by a third compressor 22, and then cooled and condensed by a second condenser 23 (cooled by 5 ℃ water) and a second heat exchanger 25. The condensed liquid enters a storage tank 24 for separation, one part of a liquid stream iv extracted from the bottom of the storage tank 24 reflows to the high-pressure liquefied gas product tower 21, and the other part of the liquid stream iv serving as a hydrogen chloride product (namely, a high-pressure liquefied gas product (r)) enters a filling process and is directly filled into a package; a gas stream ii is withdrawn from the top of the storage tank 24 and enters the demister 11 for recycling.

One part of the liquid stream v extracted from the tower bottom of the high-pressure liquefied gas product tower 21 directly enters the low-pressure liquefied gas product tower 26, and the other part of the liquid stream v enters the second heat exchanger 25 for heat exchange and then returns to the high-pressure liquefied gas product tower 21. The low pressure liquefied gas product tower 26 is operated at 1.5MPa with the reboiler 29 at the bottom heated by low pressure steam and the third condenser 27 at the top cooled by 5 deg.C water.

After the gas extracted from the top of the low-pressure liquefied gas product tower 26 enters the third condenser 27 for condensation, the obtained liquid enters the second separation tank 28 for gas-liquid separation, the gas stream iii extracted from the top of the second separation tank is returned to the demister 11 for recycling, and the liquid stream vi extracted from the bottom of the second separation tank is used as reflux liquid and refluxed to the low-pressure liquefied gas product tower 26.

The liquid extracted from the tower bottom of the low-pressure liquefied gas product tower 26 is the sulfur dioxide product (namely, low-pressure liquefied gas product (c)), and the sulfur dioxide product is directly filled into a product package in the filling procedure. The parameters of each stream are given in table 1.

Table 1 table of parameters for each stream obtained in example 1

Example 2:

and (3) recovering, separating and purifying from the industrial tail gas mixture to be treated in No. 2: hydrogen sulfide and hydrogen chloride, wherein the hydrogen sulfide is a low-pressure liquefied gas, and the hydrogen chloride is a high-pressure liquefied gas.

The device for implementing the method for recycling the chemical tail gas is shown in figure 1, and the specific process flow of the method is as follows:

containing light component impurities (H)₂、N₂、O₂) And the industrial tail gas mixture 2# of heavy component impurities, hydrogen chloride (high-pressure liquefied gas product) and hydrogen sulfide (low-pressure liquefied gas product) is treated by a demister 11, liquid, foam or solid particles which are possibly carried are removed, and then the mixture enters a heat exchanger 12 to be cooled to the normal temperature of 25 ℃, and then enters a supercharger 13 to be pressurized to 0.2 MPa. After the compressed gas is treated by the separator 14, a heavy component liquid stream i (namely, a heavy component impurity stream) is extracted from the bottom of the compressed gas and is recovered as mother liquor, and a gas stream i extracted from the top of the compressed gas enters a first compressor15, a second pressurization treatment is carried out, and pressurization is carried out to 1.0 MPa. The compressed gas stream i is introduced directly into the lower part of the recovery column 16 and treated, at an operating pressure of 1.0 MPa.

And a heavy component liquid stream ii separated from the bottom of the recovery tower 16 is a liquid mixture containing mother liquor impurities (namely, a heavy component impurity stream II) which is recovered as mother liquor, and the heavy component impurity stream ii and the obtained heavy component-containing liquid stream i are returned to the reaction process for recycling. The low-temperature gaseous mixture is extracted from the top of the recovery tower 16, passes through the first heat exchanger 17, exchanges heat with the compressed gas to raise the temperature, enters the second compressor 18 to be pressurized, is compressed to 5.0MPa, the compressed gas is output from the outlet of the second compressor 18 and enters the first heat exchanger 17 to exchange heat to lower the temperature, and the cooled material enters the first condenser 19 (cooled by water at the temperature of-30 ℃) to be condensed and liquefied. The condensed liquid enters a first separation tank 20 for gas-liquid separation, a low-concentration hydrogen chloride byproduct containing light component impurities (namely, a light component impurity stream (c)) is extracted from the top of the first separation tank, and a part of a liquid stream iii extracted from the bottom of the first separation tank flows back to a recovery tower 16, and the other part of the liquid stream enters a high-pressure liquefied gas product tower 21 (the tower is an improved heat pump rectifying tower, and the operating pressure of the tower is 4.0MPa) for treatment.

The gas extracted from the top of the high-pressure liquefied gas product tower 21 is compressed to 7.0MPa by a third compressor 22, and then cooled and condensed by a second condenser 23 (cooled by 5 ℃ water) and a second heat exchanger 25. The condensed liquid enters a storage tank 24 for separation, one part of a liquid stream iv extracted from the bottom of the storage tank 24 reflows to the high-pressure liquefied gas product tower 21, and the other part of the liquid stream iv serving as a hydrogen chloride product (namely, a high-pressure liquefied gas product (r)) enters a filling process and is directly filled into a package; a gas stream ii is withdrawn from the top of the storage tank 24 and enters the demister 11 for recycling.

One part of the liquid stream v extracted from the tower bottom of the high-pressure liquefied gas product tower 21 directly enters the low-pressure liquefied gas product tower 26, and the other part of the liquid stream v enters the second heat exchanger 25 for heat exchange and then returns to the high-pressure liquefied gas product tower 21. The operating pressure of the low-pressure liquefied gas product tower 26 is 3.5MPa, a reboiler 29 at the tower bottom of the low-pressure liquefied gas product tower 26 is heated by low-pressure steam, and a third condenser 27 at the tower top is cooled by 5 ℃ water.

After the gas extracted from the top of the low-pressure liquefied gas product tower 26 enters the third condenser 27 for condensation, the obtained liquid enters the second separation tank 28 for gas-liquid separation, the gas stream iii extracted from the top of the second separation tank is returned to the demister 11 for recycling, and the liquid stream vi extracted from the bottom of the second separation tank is used as reflux liquid and refluxed to the low-pressure liquefied gas product tower 26.

The liquid extracted from the tower bottom of the low-pressure liquefied gas product tower 26 is the hydrogen sulfide product (i.e. low-pressure liquefied gas product (c)), and the hydrogen sulfide product is directly filled into the product packaging material in the filling procedure. The parameters of each stream are shown in table 2.

Table 2 table of parameters for each stream obtained in example 2

Example 3:

and (3) recovering, separating and purifying from the industrial tail gas mixture to be treated: hydrogen chloride and hydrogen bromide, wherein the hydrogen chloride is a high-pressure liquefied gas, and the hydrogen bromide is a low-pressure liquefied gas; the content of light component impurities (such as hydrogen, oxygen, nitrogen and other permanent gases) in the No. 3 industrial tail gas mixture exceeds 10 percent.

The device for implementing the method for recycling the chemical tail gas is shown in fig. 2, and the specific process flow of the method is as follows:

containing light component impurities (e.g. H)₂Etc.), heavy component impurities (e.g., dibromomethane, methylene dichloride, etc.), hydrogen chloride and hydrogen bromide, and the mixture of 3# industrial tail gas to be treated is treated by a demister 11, liquid, foam or solid particles which may be entrained are removed, the obtained gas stream i directly enters a first compressor 15 for second pressurization treatment, the pressure is increased until the outlet pressure is 0.55-0.6MPa, the compressed gas stream i is directly introduced into the lower part of a recovery tower 16 and treated, and the operating pressure of the recovery tower 16 is 0.5 MPa.

Removing a liquid stream ii (namely a heavy component impurity stream II) containing dibromomethane, dichloromethane and the like from the bottom of the recovery tower 16, and collecting a low-temperature gaseous mixture from the top of the recovery tower 16; the low-temperature gaseous mixture passes through the first heat exchanger 17, exchanges heat with compressed gas, is heated up, then enters the second compressor 18 for pressurization, the second compressor 18 carries out third pressurization treatment, the pressure of the pressurized outlet gas is 5.0MPa, then enters the first heat exchanger 17 for heat exchange and cooling, and the cooled material enters the first condenser 19 (adopting water or circulating water at 0 ℃) for condensation. The liquid stream iii obtained after condensation is directly processed in a high pressure liquefied gas product column 21 operating at a pressure of 5.0 MPa.

The gas extracted from the tower top of the high-pressure liquefied gas product tower 21 is compressed by a third compressor 22 to have an outlet pressure of 10.0MPa, and then enters a second condenser 23 for cooling, the second condenser 23 adopts an ultralow-temperature refrigeration system (shown in figure 3) taking hydrogen chloride as a refrigerant as a cold source, the condensed liquid is subjected to gas-liquid separation in a storage tank 24, a part of liquid stream iv extracted from the bottom of the storage tank 24 reflows to the high-pressure liquefied gas product tower 21, a part of liquid stream iv reflows to the recovery tower 16, and the other part of liquid stream iv is extracted as a hydrogen chloride product (namely, a high-pressure liquefied gas product (iv)) and directly filled in a product package in a filling process; a light fraction impurity stream (c) is withdrawn from the top of the storage tank 24. The reboiler used in the tower bottom of the high-pressure liquefied gas product tower 21 is a second heat exchanger 25, and is heated by low-pressure steam; the liquid stream v extracted from the tower bottom of the high-pressure liquefied gas product tower 21 directly enters the low-pressure liquefied gas product tower 26, the operating pressure of the low-pressure liquefied gas product tower 26 is 4.5MPa, and the reboiler 29 at the tower bottom is heated by low-pressure steam.

The material extracted from the top of the low-pressure liquefied gas product tower 26 is cooled by a third condenser 27, the third condenser 27 uses an ultra-low temperature refrigeration system (shown in fig. 3) using hydrogen chloride as a refrigerant as a cold source, the cooled material enters a second separation tank 28, a gas stream iii extracted from the top of the second separation tank 28 returns to the demister 11 for recycling, and a liquid stream vi extracted from the bottom of the second separation tank 28 returns to the low-pressure liquefied gas product tower 26 as a reflux liquid.

The second condenser 23 and the third condenser 27 adopt hydrogen chloride as a refrigerant, and the devices and connections thereof are shown in fig. 3, and the specific process flow is as follows: the hydrogen chloride from the refrigerant buffer tank 33 is compressed by the refrigeration compressor 30 and then enters the refrigeration heat exchanger 31 for condensation and liquefaction; the refrigerant of the refrigeration heat exchanger 31 may be, for example, normal-temperature circulating water or low-temperature chilled water; the liquid hydrogen chloride condensed and liquefied by the refrigeration heat exchanger 31 enters a refrigerant storage tank 32 for storage; when the temperature reduction treatment is carried out, liquid hydrogen chloride extracted from the bottom of the refrigerant storage tank 32 is conveyed into the heat exchanger and is subjected to vaporization heat exchange; in the heat exchanger, liquid hydrogen chloride is vaporized and expanded to be used as a refrigerant of the heat exchanger, and heat exchange is carried out between the liquid hydrogen chloride and a heating medium in the heat exchanger; the vaporized hydrogen chloride after heat exchange returns to the refrigerant buffer tank 33 for recycling.

The liquid material extracted from the tower bottom of the low-pressure liquefied gas product tower 26 is a hydrogen bromide product (namely, low-pressure liquefied gas product (c)), and is extracted and directly filled into a product packaging material in a filling procedure. The parameters of each stream are shown in Table 3.

Table 3 table of parameters for each stream obtained in example 3

By utilizing the method and the treatment device provided by the application, after the industrial tail gas to be treated of three different components is purified, high-pressure liquefied gas and low-pressure liquefied gas with higher purity can be obtained, and simultaneously, the heavy component impurities of the mother liquor entrained in the mixed tail gas can be recovered. The application provides a method for recycling chemical tail gas, can solve the environmental protection problem that is caused by upstream process by-product tail gas, can also retrieve the discarded harmful component simultaneously and recycle, forms the raw and other materials that have higher resource value, has not only reduced the environmental protection expense of whole technology, has created new economic value again simultaneously.

Having described embodiments of the present invention, the foregoing description is intended to be exemplary, not exhaustive, and not limited to the embodiments disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the spirit of the invention.