Treatment device and treatment method for tail gas produced in production of methylphosphorus dichloride

Abstract

The application discloses a device and a method for treating tail gas generated in methyl phosphorus dichloride production, and the device comprises a condenser group, an alkali washing tower group, a concentrated sulfuric acid drying tower and a chloromethane recovery group. The condenser group comprises at least two-stage serially connected condensers, the first-stage condenser is used for passing in the tail gas, the alkali washing tower group comprises at least two-stage serially connected alkali washing towers, the first-stage alkali washing tower is communicated with the last-stage condenser, the concentrated sulfuric acid drying tower is communicated with the last-stage alkali washing tower, the chloromethane recovery group is communicated with the concentrated sulfuric acid drying tower, the condenser group is used for sequentially condensing the passed-in tail gas to collect liquid phosphorus trichloride, the alkali washing tower group is used for sequentially alkali washing and impurity removing of tail gas discharged from the last-stage condenser, and the chloromethane recovery group is used for recovering chloromethane from tail gas discharged from the concentrated sulfuric acid drying tower. The device can well recover phosphorus trichloride and chloromethane, improves the recovery rate, reduces the treatment cost and improves the environmental protection performance.

Description

Technical Field

[0001] This invention relates to a treatment device and method for the tail gas generated during the production of methyl phosphorus dichloride. Background Technology

[0002] Currently, the tail gas from the production of methyl dichloride typically contains phosphorus trichloride (PCl3, 30%), chloromethane (CH3Cl, 15%), and nitrogen (N2, 55%). Existing technologies generally employ a two-stage alkaline scrubbing followed by incineration process for treating methyl dichloride tail gas. This process has the following drawbacks: 1. Serious waste of resources: Low phosphorus trichloride recovery rate: The two-stage alkaline washing process cannot completely remove phosphorus trichloride. Unrecovered phosphorus trichloride decomposes into PO4³⁻ and Cl⁻ during incineration, resulting in the loss of phosphorus resources. Chloromethane is destroyed: direct incineration completely converts chloromethane into CO2 and HCl, without proper recovery of chloromethane.

[0003] 2. High risk of secondary pollution: Phosphorus-containing wastewater pollution: The wastewater discharged from the alkaline washing tower contains PO4³⁻ (concentration 50~100 mg / L) and Cl⁻ (concentration 2000~3000 mg / L), which requires additional treatment, increasing the pollution risk and treatment costs; Acid gas escape: The efficiency of alkaline washing is affected by fluctuations in operating conditions, and the concentration of HCl emissions often exceeds the national standard.

[0004] 3. Energy and resource waste: Incineration has high energy consumption: it requires additional fuel and accounts for a large proportion of operating costs. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the defects of the prior art and provide a treatment device for the tail gas generated during the production of methyl dichloride. It can effectively recover phosphorus trichloride and chloromethane, improve the recovery rate, reduce the treatment cost, and improve the environmental performance.

[0006] To solve the above-mentioned technical problems, the technical solution of the present invention is: a treatment device for tail gas generated during the production of methyl phosphorus dichloride, wherein the tail gas contains at least phosphorus trichloride and chloromethane, comprising: A condenser assembly comprising at least two stages of condensers connected in series, the most basic stage of which is used to introduce exhaust gas. Alkali washing tower group, which includes at least two alkali washing towers connected in series, with the first alkali washing tower connected to the last condenser. The concentrated sulfuric acid drying tower is connected to the final stage alkaline washing tower. A chloromethane recovery unit, wherein the chloromethane recovery unit is connected to a concentrated sulfuric acid drying tower; wherein... The condenser assembly is used to condense the incoming exhaust gas sequentially to collect liquid phosphorus trichloride. The alkaline scrubbing tower group is used to sequentially perform alkaline scrubbing and impurity removal on the exhaust gas discharged from the final stage condenser. The concentrated sulfuric acid drying tower is used to absorb at least some moisture from the exhaust gas discharged from the final stage alkaline washing tower. The chloromethane recovery unit is used to recover chloromethane from the tail gas discharged from the concentrated sulfuric acid drying tower.

[0007] Furthermore, a specific structure of a condenser assembly is provided, wherein the condenser includes a first exhaust gas inlet and a first exhaust gas outlet. In two adjacent condensers, the first exhaust gas outlet of the front condenser is connected to the first exhaust gas inlet of the rear condenser, and the first exhaust gas inlet of the most basic condenser is used to introduce exhaust gas.

[0008] Furthermore, in order to collect the condensed phosphorus trichloride, the treatment device also includes a phosphorus trichloride temporary storage tank, and the condenser also includes a condensate collection port, which is connected to the inlet of the corresponding phosphorus trichloride temporary storage tank.

[0009] Furthermore, a specific structure of an alkaline scrubbing tower group is provided. The alkaline scrubbing tower includes a second tail gas inlet and a second tail gas outlet. In two adjacent alkaline scrubbing towers, the second tail gas outlet of the front alkaline scrubbing tower is connected to the second tail gas inlet of the rear alkaline scrubbing tower, and the second tail gas inlet of the most basic alkaline scrubbing tower is connected to the final stage condenser.

[0010] Furthermore, in order to completely remove the hydrolysis products of phosphorus trichloride, the final alkaline washing tower uses a 5% NaOH solution as the alkaline washing solution, while the remaining alkaline washing towers use a 10% NaOH solution.

[0011] Furthermore, in order to pre-treat the tail gas entering the concentrated sulfuric acid drying tower and separate and remove some of the condensate, the treatment device also includes a gas-liquid separator. The inlet of the gas-liquid separator is connected to the alkaline washing tower group, and the outlet of the gas-liquid separator is connected to the concentrated sulfuric acid drying tower. The tail gas discharged from the final alkaline washing tower first enters the gas-liquid separator to separate and remove some of the condensate before entering the concentrated sulfuric acid drying tower.

[0012] Furthermore, in order to separate and recover the sulfuric acid mist carried in the tail gas after treatment by the concentrated sulfuric acid drying tower, the treatment device also includes a sulfuric acid demister. The inlet of the sulfuric acid demister is connected to the concentrated sulfuric acid drying tower, and the outlet of the sulfuric acid demister is connected to the chloromethane recovery group. The tail gas after treatment by the concentrated sulfuric acid drying tower enters the sulfuric acid demister to separate and recover the sulfuric acid mist carried in the tail gas before being sent to the chloromethane recovery group.

[0013] Furthermore, a specific structure for a chloromethane recovery unit is provided, the chloromethane recovery unit including a chloromethane storage tank and at least two compression and condensation units connected in series, the compression and condensation units including a compressor and a recovery cooler, the outlet of the compressor being connected to an inlet of the corresponding recovery cooler, the inlet of the compressor in the most basic compression and condensation unit being used to introduce the tail gas after treatment by the concentrated sulfuric acid drying tower, and the coolant outlet of the recovery cooler in the last compression and condensation unit being connected to the chloromethane storage tank.

[0014] Furthermore, in order to incinerate the treated residual exhaust gas so that it can be discharged, the treatment device also includes an exhaust gas incineration device, the inlet of which is connected to the exhaust gas outlet of the chloromethane recovery unit.

[0015] Furthermore, in order to control the flow rate of the tail gas generated during the production of methyl dichloride, the treatment device also includes a tail gas buffer tank, which is connected to the primary stage condenser. The tail gas buffer tank is used to stabilize the flow rate of the incoming tail gas and discharge it into the primary stage condenser.

[0016] The present invention also provides a treatment method based on a treatment device for tail gas generated during the production of methyl phosphorus dichloride, the method comprising the following steps: The incoming exhaust gas is condensed to collect liquid phosphorus trichloride; The exhaust gas discharged after condensation treatment is subjected to multiple alkaline washings to remove impurities and phosphorus trichloride hydrolysis products from the exhaust gas. The exhaust gas discharged after alkaline washing is subjected to moisture absorption to reduce the moisture content in the exhaust gas to the specified value. Chloromethane is recovered from the exhaust gas after moisture absorption.

[0017] By adopting the above technical solution, this invention uses a condenser group to perform multi-stage condensation on the incoming tail gas to recover as much liquid phosphorus trichloride as possible with high purity, avoiding losses due to phosphorus trichloride hydrolysis. An alkaline scrubbing tower group then performs multi-stage alkaline scrubbing on the tail gas after condensation to remove impurities, thus completely removing a small portion of the hydrolysis products generated by phosphorus trichloride. A concentrated sulfuric acid drying tower absorbs moisture from the tail gas after alkaline scrubbing, reducing the water content to below 10 ppm. A chloromethane recovery group then performs multi-stage compression and condensation to recover chloromethane with high purity from the tail gas. Finally, the remaining residual gas in the tail gas can be burned through a tail gas incineration device, reducing incineration energy consumption and improving combustion efficiency. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of the tail gas treatment device generated during the production of methyl phosphorus dichloride according to the present invention. Figure 2 This is a schematic diagram showing the connection between the condenser assembly and the phosphorus trichloride storage tank of the present invention. Figure 3 This is a schematic diagram of the layout of the alkali washing tower assembly of the present invention; Figure 4 This is a schematic diagram of the arrangement of the chloromethane recovery unit of the present invention; wherein, Condenser assembly; 1. Condenser; 11. First exhaust gas inlet; 12. First exhaust gas outlet; 13. Cooling medium inlet; 14. Cooling medium outlet; 1. Alkali washing tower assembly; 2. Alkali washing tower; 21. Second tail gas inlet; 22. Second tail gas outlet; 23. Circulating pump; 24. Circulating cooler; 3. Concentrated sulfuric acid drying tower; 4. Chloromethane recovery unit; 41. Compressor; 42. Recovery cooler; 43. Chloromethane temporary storage tank; 5. Phosphorus trichloride temporary storage tank; 6. Gas-liquid separator; 7. Sulfuric acid demister; 8. Exhaust gas incineration devices; 9. Exhaust gas buffer tank. Detailed Implementation

[0019] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0020] Example 1: As Figures 1-4 As shown, a treatment device for tail gas generated during the production of methyl phosphorus dichloride is disclosed. The tail gas mainly contains phosphorus trichloride, chloromethane, and nitrogen. The treatment device includes: The condenser group 10 includes at least two stages of condensers 1 connected in series, with the primary condenser 1 used to introduce exhaust gas. Alkali washing tower group 20 includes at least two stages of alkali washing tower 2 connected in series, with the first stage alkali washing tower 2 connected to the last stage condenser 1. Concentrated sulfuric acid drying tower 3 is connected to the final stage alkaline washing tower 2; Chloromethane recovery group 4 is connected to concentrated sulfuric acid drying tower 3; wherein... The condenser group 10 is used to condense the incoming exhaust gas in sequence to collect liquid phosphorus trichloride; Alkali washing tower group 20 is used to sequentially perform alkaline washing and impurity removal on the tail gas discharged from the last stage condenser 1. The concentrated sulfuric acid drying tower 3 is used to absorb at least some moisture from the tail gas discharged from the final stage alkaline washing tower 2. Chloromethane recovery unit 4 is used to recover chloromethane from the tail gas discharged from the concentrated sulfuric acid drying tower 3.

[0021] Preferably, in this embodiment, there are two condensers 1 connected in series and three alkali washing towers 2 connected in series; in some embodiments, the number of condensers 1 connected in series can also be increased as needed, and is not limited to two, and the number of alkali washing towers 2 connected in series can also be increased as needed, and is not limited to three.

[0022] like Figure 2 As shown, the condenser 1 includes a first exhaust gas inlet 11 and a first exhaust gas outlet 12. In two adjacent condensers 1, the first exhaust gas outlet 12 of the front condenser 1 is connected to the first exhaust gas inlet 11 of the rear condenser 1. The first exhaust gas inlet 11 of the most basic condenser 1 is used to introduce exhaust gas. Of course, the condenser 1 also includes a cooling medium inlet 13 and a cooling medium outlet 14 for the flow of cooling medium to cool the exhaust gas entering the condenser 1.

[0023] Specifically, in order to collect the condensed phosphorus trichloride, such as Figure 2 As shown, the processing device also includes a phosphorus trichloride storage tank 5, and the condenser 1 also includes a condensate collection port, which is connected to the inlet of the corresponding phosphorus trichloride storage tank 5; specifically, the outlet of the phosphorus trichloride storage tank 5 can be connected by a pipeline and reused in the methyl dichloride preparation system.

[0024] In this embodiment, the condensation temperature of the first-stage condenser 1 is -10℃ to -5℃, and the condensation temperature of the second-stage condenser 1 is -15℃ to -10℃. The two-stage series condensation recovers 95% to 96% of the liquid phosphorus trichloride (purity ≥99.5%) to avoid most of the phosphorus trichloride hydrolysis loss. The tail gas after treatment by the condenser group 10 (containing CH3Cl (about 15%), N2 (about 75%) and trace amounts of PCl3 (≤5%)) enters the alkaline washing tower group 20 for alkaline washing. The condenser 1 is specifically a shell and tube condenser 1, and the cooling medium is cold heat transfer oil.

[0025] Specifically, Figure 3 A specific structure of an alkaline scrubbing tower group 20 is provided. The alkaline scrubbing tower 2 includes a second tail gas inlet 21 and a second tail gas outlet 22. In two adjacent alkaline scrubbing towers 2, the second tail gas outlet 22 of the front alkaline scrubbing tower 2 is connected to the second tail gas inlet 21 of the rear alkaline scrubbing tower 2. The second tail gas inlet 21 of the most basic alkaline scrubbing tower 2 is connected to the first tail gas outlet 12 of the last stage condenser 1.

[0026] Specifically, see Figure 3As shown, the alkaline washing tower 2 is equipped with an external circulation section, which includes a circulation pump 23 and a circulation cooler 24. The inlet of the circulation pump 23 is connected to the bottom of the alkaline washing tower 2, and the outlet of the circulation pump 23 is connected to the circulating liquid inlet of the circulation cooler 24. The circulating liquid outlet of the circulation cooler 24 is connected to the circulating liquid inlet of the alkaline washing tower 2. The circulating liquid inlet is located on the top side of the alkaline washing tower 2. It should be noted that the number of circulation pumps 23 can be set according to requirements. When multiple circulation pumps 23 are set, they are set in parallel. Of course, the alkaline washing tower 2 has a liquid alkali inlet for introducing liquid alkali and a water inlet for introducing raw water. The wastewater after spraying alkaline washing in the alkaline washing tower 2 is discharged as wastewater after neutralization and sedimentation (pH 7~8).

[0027] Specifically, the second tail gas outlet 22 of the alkaline scrubbing tower 2 is located at the top of the alkaline scrubbing tower 2, and the alkaline scrubbing tower 2 is filled with Pall ring packing. In this embodiment, in order to completely remove the hydrolysis products of phosphorus trichloride, the alkaline scrubbing solution used in the last alkaline scrubbing tower 2 is a 5% NaOH solution, and the alkaline scrubbing solution used in the remaining alkaline scrubbing towers 2 is a 10% NaOH solution. In this embodiment, there are three alkaline scrubbing towers 2. The first alkaline scrubbing tower 2 performs the first stage of alkaline scrubbing to neutralize the hydrolysis products of phosphorus trichloride. The second alkaline scrubbing tower 2 performs the second stage of alkaline scrubbing to further remove residual HCl (removal rate ≥99%) and PCl3 (removal rate ≥99.9%). The third stage of alkaline scrubbing is used to deeply remove the remaining hydrogen chloride (residual HCl <100ppm).

[0028] Specifically, in order to pre-treat the tail gas entering concentrated sulfuric acid drying tower 3, and to separate and remove some of the condensate, such as... Figure 1 As shown, the treatment device also includes a gas-liquid separator 6. The inlet of the gas-liquid separator 6 is connected to the second tail gas outlet 22 of the final stage alkaline washing tower 2. The outlet of the gas-liquid separator 6 is connected to the gas inlet of the concentrated sulfuric acid drying tower 3. The tail gas discharged from the final stage alkaline washing tower 2 first enters the gas-liquid separator 6 to separate and remove part of the condensate before entering the concentrated sulfuric acid drying tower 3 for moisture absorption.

[0029] Specifically, in order to separate and recover the sulfuric acid mist carried in the tail gas after treatment by concentrated sulfuric acid drying tower 3, such as Figure 1 As shown, the treatment device also includes a sulfuric acid demister 7. The inlet of the sulfuric acid demister 7 is connected to the gas outlet of the concentrated sulfuric acid drying tower 3, and the outlet of the sulfuric acid demister 7 is connected to the chloromethane recovery group 4. The tail gas after treatment by the concentrated sulfuric acid drying tower 3 enters the sulfuric acid demister 7 to separate and recover the sulfuric acid mist carried by the tail gas before being sent to the chloromethane recovery group 4.

[0030] In this embodiment, the circulating spray liquid used in the concentrated sulfuric acid drying tower 3 is 98% concentrated sulfuric acid (circulation rate 25 m³ / h, temperature 20~30℃). The concentrated sulfuric acid drying tower 3 can be the existing concentrated sulfuric acid drying tower 3, which has its own concentrated sulfuric acid circulation system to circulate the incoming concentrated sulfuric acid. This embodiment will not elaborate on this.

[0031] In this embodiment, the tail gas, after preliminary purification by the gas-liquid separator 6, is transported to the concentrated sulfuric acid drying tower 3, where it comes into full contact with the concentrated sulfuric acid flowing counter-currently from top to bottom inside the tower, completing the moisture absorption and drying process. The tail gas after treatment by the concentrated sulfuric acid drying tower 3 has a dew point ≤ -60℃ and a water content ≤ 10 ppm.

[0032] Specifically, such as Figure 4 As shown, a specific structure of a chloromethane recovery unit 4 is provided. The chloromethane recovery unit 4 includes a chloromethane storage tank 43 and at least two compression and condensation units connected in series. The compression and condensation units include a compressor 41 and a recovery cooler 42. The outlet of the compressor 41 is connected to an inlet of the corresponding recovery cooler 42. The inlet of the compressor 41 in the first-stage compression and condensation unit is used to introduce the tail gas after treatment by the concentrated sulfuric acid drying tower 3. The coolant outlet of the recovery cooler 42 in the last-stage compression and condensation unit is connected to the chloromethane storage tank 43. In this embodiment, the compressor 41 is specifically a centrifugal compressor 41. The compression and condensation units are provided in two sets. The parameters of the first-stage compressor 41 are: pressure 0.01→0.5 MPa, exhaust temperature ≤60℃; the parameters of the second-stage compressor 41 are: pressure 0.5→1.0 MPa. MPa, exhaust temperature ≤70℃; the recovery cooler 42 adopts a shell and tube heat exchanger, and the cooling medium is cold heat transfer oil (-15℃). In this embodiment, the compression of the two-stage compressor 41 is combined with the condensation of the recovery cooler 42 to recover 90%~95% of CH3Cl (purity ≥99.9%, dew point ≤-60℃).

[0033] Specifically, such as Figure 1 As shown, in order to incinerate the treated residual tail gas (N2+ residual CH3Cl) so that it can be discharged, the treatment device also includes a tail gas incineration device 8, the inlet of which is connected to the tail gas outlet of the chloromethane recovery group 4; in this embodiment, the tail gas incineration device 8 is specifically a pyrolysis oxidation furnace.

[0034] Specifically, in order to control the flow rate of the tail gas generated during the production of methyl phosphorus dichloride, such as Figure 1 As shown, the treatment device also includes an exhaust gas buffer tank 9, which is connected to the first exhaust gas inlet 11 of the primary condenser 1. The exhaust gas buffer tank 9 is used to stabilize the flow rate of the incoming exhaust gas and discharge it into the primary condenser 1. The exhaust gas buffer tank 9 stabilizes the exhaust gas flow rate (≤100 Nm³ / h) to avoid impact on subsequent equipment.

[0035] Example 2: This example also provides a treatment method for the tail gas generated during the production of methyl phosphorus dichloride based on the treatment device in Example 1. The method includes the following steps: Stabilize exhaust gas velocity; The exhaust gas is condensed to collect liquid phosphorus trichloride; The exhaust gas discharged after condensation treatment is subjected to multiple alkaline washings to remove impurities and phosphorus trichloride hydrolysis products from the exhaust gas. The exhaust gas discharged after alkaline washing is subjected to moisture absorption to reduce the moisture content in the exhaust gas to the specified value. Chloromethane is recovered from the exhaust gas after moisture absorption; The exhaust gas after recovering chloromethane is incinerated before being discharged.

[0036] The specific embodiments described above further illustrate the technical problems, technical solutions, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A device for treating tail gas generated during the production of methyl phosphorus dichloride, wherein the tail gas contains at least phosphorus trichloride and chloromethane, characterized in that, include: A condenser assembly comprising at least two stages of condensers connected in series, the most basic stage of which is used to introduce exhaust gas. Alkali washing tower group, which includes at least two alkali washing towers connected in series, with the first alkali washing tower connected to the last condenser. The concentrated sulfuric acid drying tower is connected to the final stage alkaline washing tower. A chloromethane recovery unit, wherein the chloromethane recovery unit is connected to a concentrated sulfuric acid drying tower; wherein... The condenser assembly is used to condense the incoming exhaust gas sequentially to collect liquid phosphorus trichloride. The alkaline scrubbing tower group is used to sequentially perform alkaline scrubbing and impurity removal on the exhaust gas discharged from the final stage condenser. The concentrated sulfuric acid drying tower is used to absorb at least some moisture from the exhaust gas discharged from the final stage alkaline washing tower. The chloromethane recovery unit is used to recover chloromethane from the tail gas discharged from the concentrated sulfuric acid drying tower.

2. The device for treating tail gas generated during the production of methyl phosphorus dichloride according to claim 1, characterized in that: The condenser includes a first exhaust gas inlet and a first exhaust gas outlet. In two adjacent condensers, the first exhaust gas outlet of the front condenser is connected to the first exhaust gas inlet of the rear condenser. The first exhaust gas inlet of the most basic condenser is used to introduce exhaust gas.

3. The apparatus for treating tail gas generated during the production of methyl phosphorus dichloride according to claim 2, characterized in that, It also includes a phosphorus trichloride storage tank, and the condenser also includes a condensate collection port, which is connected to the inlet of the corresponding phosphorus trichloride storage tank.

4. The apparatus for treating tail gas generated during the production of methyl phosphorus dichloride according to claim 1, characterized in that, The alkaline scrubbing tower includes a second tail gas inlet and a second tail gas outlet. In two adjacent alkaline scrubbing towers, the second tail gas outlet of the front alkaline scrubbing tower is connected to the second tail gas inlet of the rear alkaline scrubbing tower, and the second tail gas inlet of the most basic alkaline scrubbing tower is connected to the final stage condenser.

5. The apparatus for treating tail gas generated during the production of methyl phosphorus dichloride according to claim 1, characterized in that, The final alkaline washing tower uses a 5% NaOH solution, while the remaining alkaline washing towers use a 10% NaOH solution.

6. The apparatus for treating tail gas generated during the production of methyl phosphorus dichloride according to claim 1, characterized in that, It also includes a gas-liquid separator, the inlet of which is connected to the alkaline washing tower group, and the outlet of which is connected to the concentrated sulfuric acid drying tower. The tail gas discharged from the last alkaline washing tower first enters the gas-liquid separator to separate and remove part of the condensate before entering the concentrated sulfuric acid drying tower.

7. The apparatus for treating tail gas generated during the production of methyl phosphorus dichloride according to claim 1, characterized in that, It also includes a sulfuric acid demister, the inlet of which is connected to the concentrated sulfuric acid drying tower, and the outlet of which is connected to the chloromethane recovery group. The tail gas after treatment by the concentrated sulfuric acid drying tower enters the sulfuric acid demister to separate and recover the sulfuric acid mist carried in the tail gas before being sent to the chloromethane recovery group.

8. The apparatus for treating tail gas generated during the production of methyl phosphorus dichloride according to claim 1, characterized in that, The chloromethane recovery group includes a chloromethane storage tank and at least two compression and condensation groups connected in series. Each compression and condensation group includes a compressor and a recovery cooler. The outlet of the compressor is connected to an inlet of the corresponding recovery cooler. The inlet of the compressor in the first-stage compression and condensation group is used to introduce the tail gas after treatment by the concentrated sulfuric acid drying tower. The coolant outlet of the recovery cooler in the last-stage compression and condensation group is connected to the chloromethane storage tank.

9. The apparatus for treating tail gas generated during the production of methyl phosphorus dichloride according to claim 1, characterized in that, It also includes a tail gas incineration device, the inlet of which is connected to the tail gas outlet of the chloromethane recovery unit.

10. The apparatus for treating tail gas generated during the production of methyl phosphorus dichloride according to claim 1, characterized in that, It also includes an exhaust gas buffer tank, which is connected to the primary stage condenser. The exhaust gas buffer tank is used to stabilize the flow rate of the incoming exhaust gas and discharge it into the primary stage condenser.

11. A method for treating tail gas generated during the production of methyl phosphorus dichloride based on any one of claims 1 to 10, characterized in that, The steps of the method include: The incoming exhaust gas is condensed to collect liquid phosphorus trichloride; The exhaust gas discharged after condensation treatment is subjected to multiple alkaline washings to remove impurities and phosphorus trichloride hydrolysis products from the exhaust gas. The exhaust gas discharged after alkaline washing is subjected to moisture absorption to reduce the moisture content in the exhaust gas to the specified value. Chloromethane is recovered from the exhaust gas after moisture absorption.

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