CN-224207738-U - Negative pressure treatment device for tail gas from dimethyl phosphite production

CN224207738UCN 224207738 UCN224207738 UCN 224207738UCN-224207738-U

Abstract

The utility model discloses a negative pressure treatment device for tail gas in dimethyl phosphite production, which comprises a vacuum part, a condensation part and an absorption treatment part, wherein the vacuum part comprises a buffer tank A, a Roots vacuum pump unit and a buffer tank B, the buffer tank A is provided with a tail gas inlet A, a tail gas outlet A and a methanol collecting tank A, the tail gas outlet A is connected with the Roots vacuum pump unit through an air inlet pipeline, the Roots vacuum pump unit is connected with the buffer tank B through an air outlet pipeline, the top of the buffer tank B is provided with the tail gas outlet B, the bottom of the buffer tank B is provided with the methanol collecting tank B, the condensation part comprises a condenser and the methanol collecting tank C, the tail gas outlet B is connected with the condenser, the lower end of the condenser is connected with the methanol collecting tank C, the absorption treatment part comprises a multistage water absorbing tower and an alkali absorbing tower, the multistage water absorbing tower is connected with the alkali absorbing tower, and the top of the alkali absorbing tower is provided with a tail gas output pipeline.

Inventors

CHEN WEI
WANG MEI
SUN XIAOFENG
LI PEILING
LI LIANG
WANG LINA
SI KAILI

Assignees

河南红东方化工股份有限公司

Dates

Publication Date: 20260508
Application Date: 20250530

Claims (8)

1. The negative pressure treatment device for the tail gas of the dimethyl phosphite production is characterized by comprising a vacuum part, a condensation part and an absorption treatment part; The vacuum part comprises a buffer tank A, a Roots vacuum pump unit and a buffer tank B, wherein a tail gas inlet A is formed in one side of the buffer tank A, a tail gas outlet A is formed in the top of the buffer tank A, a methanol collecting tank A is arranged at the bottom of the buffer tank A, the tail gas outlet A is connected with the Roots vacuum pump unit through an air inlet pipeline, the Roots vacuum pump unit is connected with one side of the buffer tank B through an air outlet pipeline, a tail gas outlet B is formed in the top of the buffer tank B, and a methanol collecting tank B is arranged at the bottom of the buffer tank B; The condensing part comprises a condenser and a methanol collecting tank C, the tail gas outlet B is connected with the condenser, and the lower end of the condenser is connected with the methanol collecting tank C; the absorption treatment part comprises a multi-stage water absorption tower and an alkali absorption tower, the condenser is connected with the multi-stage water absorption tower, the multi-stage water absorption tower is connected with the alkali absorption tower, and the top of the alkali absorption tower is provided with a tail gas output pipeline.
2. The negative pressure treatment device for the tail gas of the production of the dimethyl phosphite according to claim 1, wherein the Roots vacuum pump unit comprises a plurality of Roots vacuum pumps which are connected in series, the Roots vacuum pumps are provided with coolers, the coolers are positioned below the Roots vacuum pumps, the coolers are provided with methanol discharging ports, and the methanol discharging ports are connected with a small-sized collecting tank.
3. The negative pressure treatment device for the tail gas of the production of the dimethyl phosphite according to claim 1, wherein a vacuum pressure gauge A and a gas component analyzer A are arranged on the air inlet pipeline, and a vacuum pressure gauge B is arranged on the air outlet pipeline.
4. The negative pressure treatment device for the tail gas of the production of the dimethyl phosphite according to claim 1 is characterized in that a top-mounted magnetic flap level gauge is arranged on each of the methanol collecting tank A, the methanol collecting tank B and the methanol collecting tank C.
5. The negative pressure treatment device for tail gas from the production of dimethyl phosphite according to claim 1, wherein the condenser is a tubular condenser, the main body of the condenser is a graphite condenser, and the condensing medium of the condenser is chilled brine.
6. The negative pressure treatment device for the tail gas of the production of the dimethyl phosphite is characterized in that the multistage water absorption tower comprises a plurality of water absorption towers which are connected in series, the water absorption towers comprise a tower kettle and a tower body, a magnetic liquid level meter is arranged on the tower kettle, a circulating port is arranged at the bottom of the tower kettle, an air outlet is arranged at the top of the tower body, a foam remover is arranged on the upper portion of the tower body, a reflux port is arranged below the foam remover, a filler is arranged in the middle of the tower body, a grid plate is arranged below the filler, an air inlet is arranged below the grid plate, a circulating pipeline is arranged between the circulating port and the reflux port, a circulating pump, an online liquid flowmeter, an online COD (chemical oxygen demand) monitor, an acidometer and a control valve are arranged on the circulating pipeline, and the alkali absorption tower has the same setting as the water absorption tower.
7. The negative pressure treatment device for tail gas from dimethyl phosphite production according to claim 6, wherein the filler is titanium alloy or plastic.
8. The negative pressure treatment device for the tail gas produced by the dimethyl phosphite according to claim 1, wherein a gas component analyzer B and a moisture detector are arranged on the tail gas output pipeline.

Description

Negative pressure treatment device for tail gas from dimethyl phosphite production Technical Field The utility model belongs to the technical field of dimethyl phosphite production equipment, and particularly relates to a negative pressure treatment device for tail gas generated in dimethyl phosphite production. Background Dimethyl phosphite is an important product in fine chemical industry. It is used as intermediate for producing glyphosate, trichlorfon, pyrithione, omethoate, etc. and as material for organic phosphorus corrosion inhibitor, dye additive, plastic assistant and fire retardant, and may be used in synthesizing water treating agent, methylating agent, etc. as well as bactericide, antistatic agent, softening agent, etc. for synthesizing quaternary ammonium salt. Along with the rising of the domestic herbicide industry, the yield of the glyphosate is also increasing, and the demand of the dimethyl phosphite serving as a raw material for producing the glyphosate is also increasing, and the quality requirement is also increasing. At present, the most common method for industrially synthesizing the dimethyl phosphite in China takes methanol and phosphorus trichloride as raw materials, and the synthesis is carried out under certain conditions, so that the method is relatively simple and easy to operate. The production, rectification and the like of the dimethyl phosphite are all carried out under the negative pressure condition, a large amount of byproduct gas chloromethane is generated in the process, and the chloromethane and raw material methanol form production tail gas together, wherein the main component is chloromethane gas, and the production tail gas of the dimethyl phosphite is usually neutralized and dried with concentrated sulfuric acid under the negative pressure condition, so that the chloromethane is purified to a qualified level and then used as a raw material for other production such as new energy material synthesis and the like. However, the existing negative pressure system generally adopts a parallel combination of a plurality of W-shaped reciprocating vacuum pumps, has low efficiency, overlarge consumed power and large energy consumption in the operation process, has high temperature of discharged gas, relatively large power required by compression in the chloromethane recovery process, high noise, poor working environment, frequent maintenance and the like, meanwhile, methanol in tail gas is difficult to collect, hydrogen chloride is thoroughly absorbed and the like, the quality of the subsequent chloromethane and chloromethane products is greatly influenced, the cost of methanol is lost, the consumption of the concentrated sulfuric acid is greatly increased due to the fact that the overhigh content of methanol directly influences the consumption of the concentrated sulfuric acid, and the purity of the chloromethane is difficult to ensure. Therefore, in order to solve the problems of high power consumption, high noise, frequent maintenance, incomplete tail gas treatment, more impurities and the like of the vacuum pump of the negative pressure system, the improvement of the existing negative pressure treatment device for the tail gas in the production of the dimethyl phosphite is needed, so that the purposes of saving energy, reducing consumption and improving the quality of methyl chloride products are achieved. Disclosure of utility model The utility model aims to overcome the defects of the prior art and provide a negative pressure treatment device for the dimethyl phosphite production tail gas, which has the advantages of low production cost, high recovery and utilization rate and good chloromethane product quality. The utility model aims to realize that the negative pressure treatment device for the tail gas of the production of the dimethyl phosphite comprises a vacuum part, a condensation part and an absorption treatment part; The vacuum part comprises a buffer tank A, a Roots vacuum pump unit and a buffer tank B, wherein a tail gas inlet A is formed in one side of the buffer tank A, a tail gas outlet A is formed in the top of the buffer tank A, a methanol collecting tank A is arranged at the bottom of the buffer tank A, the tail gas outlet A is connected with the Roots vacuum pump unit through an air inlet pipeline, the Roots vacuum pump unit is connected with one side of the buffer tank B through an air outlet pipeline, a tail gas outlet B is formed in the top of the buffer tank B, and a methanol collecting tank B is arranged at the bottom of the buffer tank B; The condensing part comprises a condenser and a methanol collecting tank C, the tail gas outlet B is connected with the condenser, and the lower end of the condenser is connected with the methanol collecting tank C; the absorption treatment part comprises a multi-stage water absorption tower and an alkali absorption tower, the condenser is connected with the multi-stage water absorption tower, the multi-stage wa