Recovery device for carbon oxysulfide in tail gas of integrated chlorination process

Abstract

The invention discloses a device for recovering carbon oxysulfide in tail gas of an integrated chlorination process, which relates to the technical field of tail gas recovery and comprises a tail gas compressor, a tail gas storage tank, a first freezing dryer, a second freezing dryer, a rectifying tower, a carbon oxysulfide storage tank and a solvent tank, the tail gas compressor, the tail gas storage tank, the first freezing dryer, the second freezing dryer, the rectifying tower and the carbon oxysulfide storage tank are sequentially communicated through a tail gas discharge pipeline; and liquid outlets of the first freezing dryer and the second freezing dryer are communicated with the solvent tank through solvent recovery pipelines. According to the device for recycling the carbon oxysulfide in the tail gas of the integrated chlorination process, integrated gas-liquid separation operation is achieved on the tail gas through the first freezing dryer, the second freezing dryer and the rectifying tower, so that the overall recycling device is smaller in occupied area and higher in recycling efficiency.

Description

Technical Field

[0001] The invention relates to the technical field of tail gas recovery, and in particular to a device for recovering carbon oxysulfide in tail gas of an integrated chlorination process. Background Art

[0002] Carbonyl sulfide, also known as carbonyl oxysulfide and carbonyl sulfide, is a colorless gas with the smell of rotten eggs under normal conditions. It is an inorganic carbon compound with a structure similar to carbon disulfide and carbon dioxide. The gaseous COS molecule is linear, with one carbon atom connected to an oxygen atom and a sulfur atom by two double bonds.

[0003] Carbonyl sulfide is stable, but reacts violently with oxidants and corrodes metals in the presence of water. It is flammable and toxic, but like hydrogen sulfide, people tend to underestimate its concentration in exhaust gas.

[0004] Carbonyl sulfide can replace methyl bromide and phosphine and be used as a fumigant. In organic synthesis, it is used to synthesize thioacids, substituted thiazoles, insecticides such as badan, herbicides such as avenda, and cypermethrin. In the petrochemical industry, it is used as calibration gas and standard gas for online instruments.

[0005] Chlorination is a reaction that introduces chlorine atoms into the molecules of a compound. It is an important unit reaction in pharmaceutical chemistry and is used in various fields such as API, agriculture, light industry, rubber, etc. The tail gas of the chlorination process often contains by-product hydrogen chloride, organic solvents and other by-products, with complex components and difficult to recover.

[0006] At present, the common treatment method of solid phosgene chlorination tail gas is: firstly, the hydrogen chloride in the tail gas is recovered by water absorption, and then the remaining tail gas is treated with liquid alkali to react the carbon oxysulfide therein into sodium carbonate and sodium hydrosulfide, and then the sodium hydrosulfide is oxidized into sodium thiosulfate with hydrogen peroxide, and the solid waste obtained after the wastewater is concentrated is treated separately. This treatment method not only wastes the valuable carbon oxysulfide byproduct, but also generates a large amount of solid waste and wastewater, which invisibly increases the cost of waste treatment.

[0007] How to develop an integrated recovery device for carbon oxysulfide in tail gas of chlorination process to purify carbon hydrosulfide produced in chlorination process to the greatest extent with the smallest footprint has become a technical problem that needs to be solved urgently by technicians in this field. Summary of the invention

[0008] The purpose of the present invention is to provide a device for recovering carbon oxysulfide in tail gas of an integrated chlorination process, so as to solve the problems listed in the background technology.

[0009] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0010] The present invention discloses a device for recovering carbon oxysulfide in tail gas of an integrated chlorination process, comprising a tail gas compressor, a tail gas storage tank, a first cold dryer, a second cold dryer, a distillation tower, a carbon oxysulfide storage tank and a solvent tank, wherein the tail gas compressor, the tail gas storage tank, the first cold dryer, the second cold dryer, the distillation tower and the carbon oxysulfide storage tank are connected in sequence through a tail gas discharge pipeline; and the discharge ports of the first cold dryer and the second cold dryer are connected to the solvent tank through a solvent recovery pipeline.

[0011] Preferably, it also includes an adsorption tank, a primary filter, a secondary filter and a tertiary filter, the adsorption tank is connected to the exhaust gas exhaust pipeline between the exhaust gas compressor and the exhaust gas storage tank, the primary filter is connected to the exhaust gas exhaust pipeline between the exhaust gas storage tank and the first cold dryer, the secondary filter and the tertiary filter are connected to the exhaust gas exhaust pipeline between the first cold dryer and the second cold dryer in sequence.

[0012] Preferably, the exhaust gas compressor is a screw air compressor.

[0013] Preferably, the adsorption tank is filled with activated carbon.

[0014] Preferably, the gas outlet of the carbon oxysulfide storage tank is connected to a carbon oxysulfide transfer pump.

[0015] Preferably, the inner side walls of the solvent recovery pipe and the tail gas emission pipe are coated with an anti-corrosion coating.

[0016] Compared with the prior art, the beneficial technical effects of the present invention are:

[0017] The invention discloses a device for recovering carbon oxysulfide in tail gas of an integrated chlorination process. The device realizes the purification operation of tail gas through a three-stage filter to ensure the purity of the collected carbon oxysulfide, and realizes the primary separation of gas and liquid through a first cold dryer. The separated solvent overflows into a solvent tank through a solvent recovery pipeline for collection, and the separated gas is discharged into a second cold dryer through a tail gas discharge pipeline; the gas after the primary separation is separated again through the second cold dryer, and the separated liquid overflows into a solvent tank through a solvent recovery pipeline for collection, and the separated The gas is discharged into the distillation tower through the tail gas discharge pipeline for distillation separation. Carbon oxysulfide passes through each layer of the tower plate from top to bottom under the action of gravity and is discharged from the bottom of the tower; hydrogen chloride, driven by the pressure difference, passes through each layer of the tower plate from bottom to top through the openings evenly distributed on the tower plate and is discharged from the top of the tower. A certain amount of liquid is stored on each tower plate. When the gas passes through the liquid layer on the plate, the two phases contact and mass transfer are carried out. The integrated gas-liquid separation operation of the tail gas is realized through the first cold dryer, the second cold dryer and the distillation tower, so that the overall recovery device occupies a smaller area and has a higher recovery efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The present invention will be further described below in conjunction with the accompanying drawings.

[0019] Figure 1 The present invention is a schematic diagram of the layout of a device for recovering carbon oxysulfide in tail gas of an integrated chlorination process.

[0020] Explanation of the reference numerals: 1. exhaust gas compressor; 2. exhaust gas storage tank; 3. adsorption tank; 4. primary filter; 5. first cold dryer; 6. secondary filter; 7. tertiary filter; 8. second cold dryer; 9. distillation tower; 10. carbon oxysulfide storage tank; 11. carbon oxysulfide transfer pump; 12. solvent tank; 13. solvent recovery pipeline; 14. exhaust gas emission pipeline. DETAILED DESCRIPTION

[0021] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0022] like Figure 1 As shown, a device for recovering carbon oxysulfide in tail gas of an integrated chlorination process comprises a tail gas compressor 1, a tail gas storage tank 3, a first cold dryer 5, a second cold dryer 8, a distillation tower 9, a carbon oxysulfide storage tank 10 and a solvent tank 12, wherein the tail gas compressor 1, the tail gas storage tank 3, the first cold dryer 5, the second cold dryer 8, the distillation tower 9 and the carbon oxysulfide storage tank 10 are connected in sequence through a tail gas discharge pipeline 14; the discharge ports of the first cold dryer 5 and the second cold dryer 8 are connected to the solvent tank 12 through a solvent recovery pipeline 13;

[0023] The first cold dryer is used to realize the initial separation of gas and liquid, the separated solvent overflows into the solvent tank through the solvent recovery pipeline for collection, and the separated gas is discharged into the second cold dryer through the tail gas discharge pipeline; the gas after the initial separation is separated again by the second cold dryer, the separated liquid overflows into the solvent tank through the solvent recovery pipeline for collection, and the separated gas is discharged into the distillation tower through the tail gas discharge pipeline for distillation separation, and carbon oxysulfide passes through each layer of the tower plate from top to bottom under the action of gravity and is discharged from the bottom of the tower; hydrogen chloride, driven by the pressure difference, passes through each layer of the tower plate from bottom to top through the openings evenly distributed on the tower plate and is discharged from the top of the tower, a certain amount of liquid is stored on each tower plate, and when the gas passes through the liquid layer on the plate, the two phases contact for mass transfer, and the integrated gas-liquid separation operation of the tail gas is realized through the first cold dryer, the second cold dryer and the distillation tower, so that the overall recovery device occupies a smaller area and has a higher recovery efficiency.

[0024] Among them, the refrigeration system of the first and second cold dryers belongs to compression refrigeration, which is composed of four basic components, namely, a refrigeration compressor, a condenser, an evaporator, and an expansion valve. They are connected in sequence to form a closed system; by replacing different refrigerants in the first and second cold dryers, and making the refrigerant continuously circulate in the system to change its state and exchange heat with the compressed exhaust gas and the cooling medium, the temperature of the compressed exhaust gas drops, and the liquid solvent in the exhaust gas is precipitated. The solvent condensed in the compressed exhaust gas, the treated exhaust gas and impurities are separated through the condenser, and the solvent is discharged into the solvent tank through the drain port and the solvent recovery pipeline.

[0025] Specifically, it also includes an adsorption tank 2, a primary filter 4, a secondary filter 6 and a tertiary filter 7, the adsorption tank 2 is connected to the exhaust gas discharge pipeline 14 between the exhaust gas compressor 1 and the exhaust gas storage tank 3, the primary filter 4 is connected to the exhaust gas discharge pipeline 14 between the exhaust gas storage tank 3 and the first cold dryer 5, the secondary filter 6 and the tertiary filter 7 are sequentially connected to the exhaust gas discharge pipeline 14 between the first cold dryer 5 and the second cold dryer 8;

[0026] The adsorption tank 2 is filled with activated carbon, which can absorb moisture in the exhaust gas in advance and can also adsorb a small amount of hydrogen sulfide to prevent carbon sulfide or hydrogen sulfide from dissolving in water and corroding the first cold dryer and the exhaust gas discharge pipeline;

[0027] The first-stage filter is a pre-filter, which is installed at the front air inlet of the first cold dryer to filter large particle pollutants in the exhaust gas. At the same time, it can further filter the residual moisture in the exhaust gas, which will increase the operating load of the equipment in the subsequent drying process of the first cold dryer;

[0028] The secondary filter is installed at the exhaust port of the first cold dryer. The function of the secondary filter is to filter the liquid and solid oil mist in the compressed exhaust gas discharged by the air compressor to ensure the dryness and cleanliness of the compressed exhaust gas;

[0029] The tertiary filter is installed behind the secondary filter to perform secondary dust removal, filtering out particulate matter that is too small to be visible to the naked eye, ensuring the purity of the treated exhaust gas.

[0030] Specifically, the exhaust gas compressor 1 is a screw air compressor.

[0031] Specifically, the gas outlet of the carbon oxysulfide storage tank 10 is connected to the carbon oxysulfide transport pump 11 .

[0032] Specifically, the inner walls of the solvent recovery pipe 13 and the tail gas emission pipe 14 are coated with an anti-corrosion coating, which can prevent the tail gas emission pipe or the solvent recovery pipe from being corroded, and further, can prevent safety accidents caused by tail gas leakage.

[0033] The use process of the present invention is as follows:

[0034] Step 1: After the chlorinated tail gas to be recovered is pressurized by the tail gas compressor, it is condensed and dried by the first cold dryer and the second cold dryer, and the liquid organic solvent is effectively condensed and recovered by the solvent tank; the gaseous hydrogen chloride and carbon oxysulfide mixed gas enters the distillation tower for distillation treatment;

[0035] Step 2, the gas phase mixture is distilled and separated in a distillation tower, hydrogen chloride is separated from the top of the tower, and carbon oxysulfide is obtained at the bottom of the tower;

[0036] Step three, carbon oxysulfide collection: the high-purity carbon oxysulfide discharged from the distillation tower enters the high-purity carbon oxysulfide storage tank for collection, and is discharged and transported through a carbon oxysulfide transport pump according to the volume of the carbon oxysulfide storage tank.

[0037] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0038] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A device for recovering carbon oxysulfide in tail gas of an integrated chlorination process, characterized in that: The invention comprises an exhaust gas compressor (1), an exhaust gas storage tank (3), a first cold dryer (5), a second cold dryer (8), a distillation tower (9), a carbon oxysulfide storage tank (10) and a solvent tank (12); the exhaust gas compressor (1), the exhaust gas storage tank (3), the first cold dryer (5), the second cold dryer (8), the distillation tower (9) and the carbon oxysulfide storage tank (10) are all connected in sequence via an exhaust gas discharge pipeline (14); and the discharge ports of the first cold dryer (5) and the second cold dryer (8) are both connected to the solvent tank (12) via a solvent recovery pipeline (13).

2. The device for recovering carbon oxysulfide in tail gas of an integrated chlorination process according to claim 1, characterized in that: It also includes an adsorption tank (2), a primary filter (4), a secondary filter (6) and a tertiary filter (7), wherein the adsorption tank (2) is connected to the exhaust gas discharge pipeline (14) between the exhaust gas compressor (1) and the exhaust gas storage tank (3), the primary filter (4) is connected to the exhaust gas discharge pipeline (14) between the exhaust gas storage tank (3) and the first cold dryer (5), and the secondary filter (6) and the tertiary filter (7) are connected to the exhaust gas discharge pipeline (14) between the first cold dryer (5) and the second cold dryer (8) in sequence.

3. The device for recovering carbon oxysulfide in tail gas of an integrated chlorination process according to claim 1, characterized in that: The tail gas compressor (1) is a screw air compressor.

4. The device for recovering carbon oxysulfide in tail gas of an integrated chlorination process according to claim 2, characterized in that: The adsorption tank (2) is filled with activated carbon.

5. The device for recovering carbon oxysulfide in tail gas of an integrated chlorination process according to claim 4, characterized in that: The gas outlet of the carbon oxysulfide storage tank (10) is in communication with the carbon oxysulfide transport pump (11).

6. The device for recovering carbon oxysulfide in tail gas of an integrated chlorination process according to claim 5, characterized in that: The inner side walls of the solvent recovery pipe (13) and the tail gas exhaust pipe (14) are coated with an anti-corrosion coating.

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