阅读说明：本技术 二氟一氯甲烷精馏残液中回收一氟二氯甲烷的设备及方法 (Equipment and method for recovering monofluoro-dichloromethane from difluorochloromethane rectification residual liquid ) 是由 孙政 刘子璇 王卫国 全文德 于 2021-06-29 设计创作，主要内容包括：本发明公开二氟一氯甲烷精馏残液中回收一氟二氯甲烷的方法,一,将精馏残液在一氟二氯甲烷回收塔(1)内对精馏残液进行精馏；二,步骤一中由一氟二氯甲烷回收塔(1)的塔顶进入的精馏残液物料精馏后通过输送泵Ⅰ(11)将一氟二氯甲烷输送至氟化反应器(12)中进行氟化反应。本发明二氟一氯甲烷精馏残液中回收一氟二氯甲烷的设备,它主要包括一氟二氯甲烷回收塔(1),一氟二氯甲烷回收塔(1)设置为精馏塔,在一氟二氯甲烷回收塔(1)的顶部设有进料槽(2),干燥器组合的出口与一氟二氯甲烷贮槽(10)的进口相连通,一氟二氯甲烷贮槽(10)的出口通过输送管Ⅴ与氟化反应器(12)相连通。(The invention discloses a method for recovering monofluoro-dichloromethane from difluorochloromethane rectification residual liquid, which comprises the following steps of firstly, rectifying the rectification residual liquid in a monofluoro-dichloromethane recovery tower (1); and secondly, after the rectification residual liquid material entering from the top of the monofluoro-dichloromethane recovery tower (1) in the step one is rectified, the monofluoro-dichloromethane is conveyed to a fluorination reactor (12) through a conveying pump I (11) for fluorination reaction. The invention relates to equipment for recovering monofluoro-dichloromethane from difluorochloromethane rectification residual liquid, which mainly comprises a monofluoro-dichloromethane recovery tower (1), wherein the monofluoro-dichloromethane recovery tower (1) is arranged as a rectification tower, the top of the monofluoro-dichloromethane recovery tower (1) is provided with a feeding groove (2), the outlet of a dryer combination is communicated with the inlet of a monofluoro-dichloromethane storage tank (10), and the outlet of the monofluoro-dichloromethane storage tank (10) is communicated with a fluorination reactor (12) through a conveying pipe V.)

1. The method for recovering monofluoro methylene dichloride from the rectification residual liquid of difluorochloromethane comprises the following steps:

discharging the rectification residual liquid to a feeding groove (2) at the top of a fluorine dichloromethane recovery tower (1), then putting the rectification residual liquid into the fluorine dichloromethane recovery tower (1) through the feeding groove (2), and then rectifying the rectification residual liquid in the fluorine dichloromethane recovery tower (1);

step two, the rectification residual liquid material entering from the top of the monofluoro-dichloromethane recovery tower (1) in the step one is firstly regulated by a manual regulating valve (3) to discharge difluorochloromethane in the rectification residual liquid material in the rectification process, a detector 14 is adopted for sampling analysis while discharging, if fluorodichloromethane is obtained after analysis, the manual regulating valve (3) is closed, the fluorodichloromethane regulating valve is opened to discharge, the fluorodichloromethane regulating valve is cooled by a condenser (4) of the monofluoro-dichloromethane, the refrigerated water separator (5) is then adopted for cooling and discharging water at 0 ℃, the dehydrated monofluoro-dichloromethane enters a fluorodichloromethane intermediate tank (6), a conveying pump II (7) between the outlet of the monofluoro-dichloromethane intermediate tank (6) and the silica gel dryer (8) and the molecular sieve dryer (9) is started, the monofluoro-dichloromethane is sequentially conveyed to the silica gel dryer (8) and the molecular sieve dryer (9) by the conveying pump II (7) to be further dehydrated, after the water content analysis is qualified, storing the fluorine dichloromethane storage tank (10), and conveying the fluorine dichloromethane to the fluorination reactor (12) through the conveying pump I (11) for fluorination reaction.

2. The method for recovering monofluoromethane from a difluoromonochloromethane rectification residue as claimed in claim 1, wherein the rectification residue is fed into a monofluoromethane rectification residue recovery column (1) through a feed tank (2) in the first step, the rectification residue is fed in a gas phase or a liquid phase, the feed tank (2) in the first step is heated by steam, the pressure and temperature control indexes of a reaction kettle of the monofluoromethane rectification residue recovery column (1) are not changed, and chloroform is controlled: the weight ratio of the AHF is 3.2-2.9, and the chloroform contains recovered monofluoro dichloromethane.

3. The method for recovering monofluoro-dichloromethane from difluorochloromethane rectification residual liquid according to claim 1, which is characterized in that in the second step, the monofluoro-dichloromethane is subjected to freeze dehydration in a freeze dehydrator (5), IV moisture in monofluoro-dichloromethane after sequentially entering a silica gel dryer (8) and a molecular sieve dryer (9) for drying is below 1000PPm and 1000PPm, the filler adopted in the molecular sieve dryer (9) is a 4A type molecular sieve, a 5A type molecular sieve or a novel molecular sieve, the silica gel dryer (8) and the 4A type molecular sieve drying dryer (9) are used together to ensure that the moisture in monofluoro-dichloromethane is less than or equal to 50PPm, the filler of the silica gel dryer (8) is silica gel, the filler of the molecular sieve dryer (9) is a 4A type molecular sieve, a 5A type molecular sieve or a novel molecular sieve, and the silica gel dryer (8) and the 4A type molecular sieve drying are used together, can ensure that the water content in F21 is less than or equal to 50 PPm.

4. The method for recovering monofluoromethanese dichloride from a difluoromethane chloride rectification residue according to claim 1, wherein the temperature of the monofluoromethanese dichloride recovery column (1) is automatically controlled to be 20-60 ℃ at the bottom of the column and 15-30 ℃ at the top of the column; the pressure self-control is set to be 0.5-0.8 MPa of the pressure of the tower kettle.

5. The equipment for recovering monofluoro-dichloromethane from difluorochloromethane rectification residual liquid is characterized by mainly comprising a monofluoro-dichloromethane recovery tower (1), wherein the monofluoro-dichloromethane recovery tower (1) is set as a rectification tower, a feeding groove (2) is arranged at the top of the monofluoro-dichloromethane recovery tower (1), a conveying pipe I arranged at the bottom of the feeding groove (2) is communicated with the top of the monofluoro-dichloromethane recovery tower (1), a discharging hole (13) is arranged at the lower part of the monofluoro-dichloromethane recovery tower (1), a detector (14) is arranged at the discharging hole (13), the inlet end of the detector (14) is communicated with the discharging hole (13), an outlet (15) is arranged at the outlet end of the detector, the outlet (15) is divided into two paths, one path is communicated with a difluorochloromethane storage tank (16) through a conveying pipe II, the other path is communicated with a condenser (4) through a conveying pipe III, the device is characterized in that a switch valve is arranged on a conveying pipe III, an inlet end and an outlet end are respectively arranged on two sides of a condenser (4), the inlet end of the condenser (4) is communicated with the conveying pipe III, the outlet end of the condenser (4) is connected with a freezing dehydrator (5), an outlet of the freezing dehydrator (5) is communicated with an inlet of a fluorine dichloromethane middle groove (6), an outlet of the fluorine dichloromethane middle groove (6) is connected with an inlet of a dryer combination through a conveying pipe IV, an outlet of the dryer combination is communicated with an inlet of a fluorine dichloromethane storage tank (10), and an outlet of the fluorine dichloromethane storage tank (10) is communicated with a fluorination reactor (12) through a conveying pipe V.

6. The apparatus for recovering monofluoromethane chloride from a rectification residue of difluoromonochloromethane as claimed in claim 5, wherein said feed tank (2) is provided with a tank body, and a jacket (17) is provided in the tank body, and the tank body is communicated with a vapor tank (18).

7. The apparatus for recovering monofluoromethane chloride from a rectification residue of difluoromonochloromethane as defined in claim 5, wherein said on-off valve is provided as a manual control valve (3).

8. The apparatus for recovering monofluoromethylene chloride from a rectification residue of difluoromonochloromethane as claimed in claim 5, wherein said dryer combination comprises a silica gel dryer (8) and a molecular sieve dryer (9), an outlet of the monofluoromethylene chloride intermediate tank (6) is connected to an inlet of the silica gel dryer (8) through a transport pipe IV, an outlet of the silica gel dryer (8) is communicated with an inlet of the molecular sieve dryer (9), an outlet of the molecular sieve dryer (9) is communicated with an inlet of a fluorodichloromethane storage tank (10), an outlet of the fluorodichloromethane storage tank (10) is communicated with the fluorination reactor (12) through a transport pipe V, and a transport pump I (11) is provided on the transport pipe V.

9. The apparatus for recovering monofluoro-dichloromethane from the rectified difluoromonochloromethane residue as claimed in claim 5, wherein the packing is arranged between the chamber and the outer shell in the monofluoro-dichloromethane recovery column (1), the packing is filled with stainless steel packing, and the packing can be in the form of an intalox saddle ring, a pall ring or a Raschig ring.

10. The apparatus for recovering monofluoromethane from a rectification residue of difluoromonochloromethane as claimed in claim 5, wherein said transfer pipe IV is provided with a transfer pump II (7).

Technical Field

The invention relates to equipment and a method for recovering monofluoro-dichloromethane from difluorochloromethane rectification residual liquid.

Background

The production principle of the chlorodifluoromethane (F22) is that trichloromethane and hydrogen fluoride are used as raw materials, and SbCl is used₅As a catalyst, according to a certain proportionThe mixture ratio is reacted under the conditions of temperature and pressure, and the main chemical equation is as follows: CHCl₃+ 2HF→CHClF₂（F22）+2HCL ， CHC₃+HF→CHCl₂F(F21)+HCl ，CHClF₂+HF→CHF₃ (F23)+HCl 。

In a difluorochloromethane (F22) device, a proper feeding proportion, a proper catalyst concentration and proper process operation conditions are required to be selected in the fluorination reaction process, so that the conversion rate and selectivity of F22 are ensured, and the side reaction is inhibited. The F22 rectification raffinate mainly comprises difluorochloromethane (F22), monofluorodichloromethane (F21), chloroform, water and the like. Wherein the contents of the components are as follows: monofluorodichloromethane (F21): 18-21%, F22: 9-12%, water: 68-70% of chloroform, and less than 1% of chloroform. Along with production operation, high-boiling-point substances are gradually accumulated in the F22 rectifying tower, and if the high-boiling-point substances are not discharged in time, the stability of the process operation of the F22 rectifying tower is influenced on one hand, and the energy consumption of a device and the product quality are influenced on the other hand.

For recycling the residual liquid of the F22 rectifying tower, few reports are reported in the literature, and the rectifying residual liquid is difficult to treat. At present, almost all F22 manufacturers can not completely solve the problem of rectification raffinate, and the method is generally adopted: the rectification residual liquid is directly discharged, and the direct discharge of the rectification residual liquid can cause pollution to the environment, so that the direct discharge is not allowed in view of the current domestic safety and environmental protection situation. In addition, F21 is an intermediate product, and is not a target product, and F21 is not completely reacted, which increases raw material consumption and production cost. Therefore, the recovery and utilization of F21 in F22 rectification residual liquid is urgent, and no equipment capable of recovering F21 in F22 rectification residual liquid exists at present.

Disclosure of Invention

The invention provides equipment and a method for recovering monofluoro-dichloromethane from difluorochloromethane rectification residual liquid, which can solve the problems of difficult recovery and utilization of the rectification residual liquid, immature recovery process technology, environmental pollution, water dehydration in F21 and the like, and the equipment can realize continuous production, has short process flow, convenient operation, good dehydration effect and high efficiency of recovering F21.

The invention adopts the following technical scheme: the method for recovering monofluoro methylene dichloride from the rectification residual liquid of difluorochloromethane comprises the following steps: discharging the rectification residual liquid to a feeding groove at the top of a monofluoro dichloromethane recovery tower, then putting the rectification residual liquid into the monofluoro dichloromethane recovery tower through the feeding groove, and then rectifying the rectification residual liquid in the monofluoro dichloromethane recovery tower; step two, the rectification residual liquid material entering from the top of the monofluoro-dichloromethane recovery tower in the step one is firstly regulated by a manual regulating valve to discharge difluorochloromethane in the rectification residual liquid material in the rectification process, a detector is adopted for sampling analysis while discharging, if the monofluoro-dichloromethane is obtained after the analysis, the manual regulating valve is closed, the monofluoro-dichloromethane regulating valve is opened to discharge the material, the material is cooled by a condenser of the monofluoro-dichloromethane, then the material enters a freezing dehydrator, the water is cooled and discharged at 0 ℃, the dehydrated monofluoro-dichloromethane enters a monofluoro-dichloromethane intermediate tank, a conveying pump II between an outlet of the monofluoro-dichloromethane intermediate tank and a silica gel dryer and a molecular sieve dryer is started, the monofluoro-dichloromethane is sequentially conveyed to the silica gel dryer and the molecular sieve dryer by the conveying pump II to be further dehydrated, the monofluoro-dichloromethane storage tank is used for storing after the moisture analysis is qualified, conveying the monofluoro methylene chloride to the fluorination reactor through a conveying pump I to carry out fluorination reaction.

In the first step of the invention, the rectification residual liquid is put into the monofluoro methylene dichloride recovery tower through the feed chute, the mode of putting the rectification residual liquid is gas phase feeding or liquid phase feeding, the feed chute in the first step is heated by steam, the pressure and temperature control indexes of a reaction kettle of the monofluoro methylene dichloride recovery tower are not changed, and the chloroform is controlled well: the weight ratio of the AHF is 3.2-2.9, and the chloroform contains recovered monofluoro dichloromethane.

In the second step of the invention, after the monofluoro-dichloromethane is subjected to freeze dehydration in a freeze dehydrator, IV moisture in the monofluoro-dichloromethane after sequentially entering a silica gel dryer and a molecular sieve dryer for drying is below 1000PPm and 1000PPm, the filler adopted in the molecular sieve dryer is a 4A type molecular sieve, a 5A type molecular sieve or a novel molecular sieve, the silica gel dryer and the 4A type molecular sieve are selected for drying and combined use, so that the moisture in the monofluoro-dichloromethane can be ensured to be less than or equal to 50PPm, the filler of the silica gel dryer is silica gel, the filler of the molecular sieve dryer is a 4A type molecular sieve, a 5A type molecular sieve or a novel molecular sieve, and the silica gel dryer and the 4A type molecular sieve are selected for drying and combined use, so that the moisture in F21 is ensured to be less than or equal to 50 PPm.

The temperature of the monofluoro-dichloromethane recovery tower is automatically controlled to be set to be 20-60 ℃ of the temperature of a tower kettle and 15-30 ℃ of the temperature of the top of the tower; the pressure self-control is set to be 0.5-0.8 MPa of the pressure of the tower kettle.

The invention relates to a device for recovering monofluoro-dichloromethane from difluorochloromethane rectification residual liquid, which mainly comprises a fluorodichloromethane recovery tower, wherein the fluorodichloromethane recovery tower is arranged as a rectification tower, a feed chute is arranged at the top of the fluorodichloromethane recovery tower, a conveying pipe I arranged at the bottom of the feed chute is communicated with the top of the fluorodichloromethane recovery tower, a discharge port is arranged at the lower part of the fluorodichloromethane recovery tower, a detector is arranged at the discharge port, the inlet end of the detector is communicated with the discharge port, the outlet end of the detector is provided with an outlet which is divided into two paths, one path is communicated with a difluorochloromethane storage tank through a conveying pipe II, the other path is communicated with a condenser through a conveying pipe III, a switch valve is arranged on the conveying pipe III, the two sides of the condenser are respectively provided with an inlet end and an outlet end, and the inlet end of the condenser is communicated with the conveying pipe III, the outlet end of the condenser is connected with a freezing dehydrator, the outlet of the freezing dehydrator is communicated with the inlet of a fluorine dichloromethane intermediate groove, the outlet of the fluorine dichloromethane intermediate groove is connected with the inlet of a dryer combination through a conveying pipe IV, the outlet of the dryer combination is communicated with the inlet of a fluorine dichloromethane storage tank, and the outlet of the fluorine dichloromethane storage tank is communicated with the fluorination reactor through a conveying pipe V.

The feeding tank is provided with a storage tank body, a jacket is arranged in the storage tank body, and the interior of the storage tank body is communicated with the steam tank. The switch valve is set as a manual regulating valve. The dryer combination comprises a silica gel dryer and a molecular sieve dryer, wherein an outlet of a fluorine dichloromethane intermediate groove is connected with an inlet of the silica gel dryer through a conveying pipe IV, an outlet of the silica gel dryer is communicated with an inlet of the molecular sieve dryer, an outlet of the molecular sieve dryer is communicated with an inlet of a fluorine dichloromethane storage tank, an outlet of the fluorine dichloromethane storage tank is communicated with a fluorination reactor through a conveying pipe V, and a conveying pump I is arranged on the conveying pipe V. And a filler is arranged between the chamber in the monofluoro-dichloromethane recovery tower and the shell, the filler is filled with stainless steel filler, and the filler can be a rectangular saddle ring, a pall ring or a Raschig ring. And a conveying pump II is arranged on the conveying pipe IV.

The invention has the following beneficial effects: after the technical scheme is adopted, the invention provides equipment for recovering monofluoro-dichloromethane from difluorochloromethane rectification residual liquid and a recovery method thereof, the method can solve the problems of difficult recovery and utilization of the rectification residual liquid, immature recovery process technology, environmental pollution, water removal from monofluoro-dichloromethane and the like, and the equipment can realize continuous production, has short process flow, is convenient to operate, has good water removal effect and high efficiency of recovering monofluoro-dichloromethane.

Drawings

FIG. 1 is a schematic structural diagram of the present invention.

Detailed Description

The invention provides a method for recovering monofluoro-dichloromethane from difluorochloromethane rectification residual liquid, which comprises the following steps: step one, discharging the rectification residual liquid to a feeding groove 2 at the top of a fluorine dichloromethane recovery tower 1, then putting the rectification residual liquid into the fluorine dichloromethane recovery tower 1 through the feeding groove 2, then rectifying the rectification residual liquid in the fluorine dichloromethane recovery tower 1, putting the rectification residual liquid into the fluorine dichloromethane recovery tower 1 through the feeding groove 2 in step one, wherein the mode of putting the rectification residual liquid is gas phase feeding or liquid phase feeding, the feeding groove 2 in step one is heated through steam, the pressure and temperature control indexes of a reaction kettle of the fluorine dichloromethane recovery tower 1 are unchanged, and chloroform is well controlled: the weight ratio of the AHF is 3.2-2.9, and the chloroform contains recovered monofluoro dichloromethane; step two, the rectification residual liquid material entering from the top of the monofluoro-dichloromethane recovery tower 1 in the step one is firstly regulated by a manual regulating valve 3 to discharge difluorochloromethane in the rectification residual liquid material in the rectification process, a detector 14 is adopted for sampling analysis while discharging, if monofluoro-dichloromethane is obtained after analysis, the manual regulating valve 3 is closed, the monofluoro-dichloromethane regulating valve is opened to discharge, the monofluoro-dichloromethane is cooled by a condenser 4 of monofluoro-dichloromethane, and then enters a freezing dehydrator 5, the monofluoro-dichloromethane after dehydration enters a monofluoro-dichloromethane intermediate tank 6, a conveying pump II 7 between the outlet of the monofluoro-dichloromethane intermediate tank 6 and a silica gel dryer 8 and a molecular sieve dryer 9 is started, the conveying pump II 7 conveys monofluoro-dichloromethane to the silica gel dryer 8 and the molecular sieve dryer 9 in sequence for further dehydration, after the water content analysis is qualified, storing the monofluoro methylene dichloride by a monofluoro methylene dichloride storage tank 10, conveying the monofluoro methylene dichloride into a fluorination reactor 12 through a conveying pump I11 for fluorination reaction, after the monofluoro methylene dichloride in the step two is subjected to freeze dehydration in a freeze dehydrator 5, sequentially passing through a silica gel dryer 8 and a molecular sieve dryer 9 for drying, wherein the IV water content in the monofluoro methylene dichloride is below 1000PPm and 1000PPm, the filler adopted in the molecular sieve dryer 9 is a 4A type molecular sieve, a 5A type molecular sieve or a novel molecular sieve, the silica gel dryer 8 and the 4A type molecular sieve drying 9 are combined for use, the water content in the monofluoro methylene dichloride can be ensured to be less than or equal to 50PPm, the filler of the silica gel dryer 8 is silica gel, the filler of the molecular sieve dryer 9 is a 4A type molecular sieve, a 5A type molecular sieve, a novel molecular sieve, and the silica gel dryer 8 and the 4A molecular sieve drying are combined for use, the water content in F21 is ensured to be less than or equal to 50PPm, the temperature of a monofluoro-dichloromethane recovery tower 1 is automatically controlled to be set to be 20-60 ℃ at the tower kettle, and the temperature of the tower top is 15-30 ℃; the pressure self-control is set to be 0.5-0.8 MPa of the pressure of the tower kettle.

In figure 1, the invention also discloses a device for recovering monofluoro-dichloromethane from difluorochloromethane rectification residual liquid, which is characterized by mainly comprising a monofluoro-dichloromethane recovery tower 1, wherein the monofluoro-dichloromethane recovery tower 1 is set as a rectification tower, a feed chute 2 is arranged at the top of the monofluoro-dichloromethane recovery tower 1, the feed chute 2 is provided with a storage chute body, a jacket 17 is arranged in the storage chute body, the storage chute body is communicated with a steam tank 18, a conveying pipe I arranged at the bottom of the feed chute 2 is communicated with the top of the monofluoro-dichloromethane recovery tower 1, a discharge port 13 is arranged at the lower part of the monofluoro-dichloromethane recovery tower 1, a detector 14 is arranged at the discharge port 13, the detector 14 is set as a component analysis instrument, the inlet end of the detector 14 is communicated with the discharge port 13, the outlet end of the detector is provided with an outlet 15, the outlet 15 is divided into two paths, and one path is communicated with a difluorochloromethane storage tank 16 through a conveying pipe II, the other path is communicated with a condenser 4 through a conveying pipe III, a switch valve is arranged on the conveying pipe III, the switch valve is set as a manual regulating valve 3, the two sides of the condenser 4 are respectively provided with an inlet end and an outlet end, the inlet end of the condenser 4 is communicated with the conveying pipe III, the outlet end of the condenser 4 is connected with a freezing dehydrator 5, the outlet of the freezing dehydrator 5 is communicated with the inlet of a fluorine dichloromethane middle groove 6, the outlet of the fluorine dichloromethane middle groove 6 is connected with the inlet of a dryer combination through a conveying pipe IV, the outlet of the dryer combination is communicated with the inlet of a fluorine dichloromethane storage tank 10, the outlet of the fluorine dichloromethane storage tank 10 is communicated with a fluorination reactor 12 through a conveying pipe V, the dryer combination comprises a silica gel dryer 8 and a molecular sieve dryer 9, the outlet of the fluorine dichloromethane middle groove 6 is connected with the inlet of the silica gel dryer 8 through the conveying pipe IV, the outlet of the silica gel dryer 8 is communicated with the inlet of the molecular sieve dryer 9, the outlet of the molecular sieve dryer 9 is communicated with the inlet of a fluorine dichloromethane storage tank 10, the outlet of the fluorine dichloromethane storage tank 10 is communicated with a fluorination reactor 12 through a conveying pipe V, a conveying pump I11 is arranged on the conveying pipe V, the conveying pump I11 is set as a shielding pump, a filler is arranged between a cavity and a shell in the fluorine dichloromethane recovery tower 1, the filler is filled with stainless steel filler, the filler can be a rectangular saddle ring, a pall ring or a Raschig ring, and a conveying pump II 7 is arranged on the conveying pipe IV.