CN113083204A

CN113083204A - NMP synthesis process

Info

Publication number: CN113083204A
Application number: CN202110515521.0A
Authority: CN
Inventors: 卢传学; 丁龙奇; 吕玉成; 赵建军; 游林
Original assignee: Chongqing Zhong Run Chemical Co ltd
Current assignee: Chongqing Zhong Run Chemical Co ltd
Priority date: 2021-05-12
Filing date: 2021-05-12
Publication date: 2021-07-09
Anticipated expiration: 2041-05-12
Also published as: CN113083204B

Abstract

The invention belongs to the technical field of chemical production, and particularly relates to an NMP (N-methyl pyrrolidone) synthesis process, which comprises the following steps: introducing a GBL raw material into a GBL elevated tank, and introducing a high-purity monomethylamine raw material into a monomethylamine elevated tank; feeding a GBL raw material with stable pressure into a static mixer from a GBL elevated tank, and feeding a high-purity monomethylamine raw material with stable pressure into the static mixer from a monomethylamine elevated tank; feeding the mixed GBL raw material and high-purity monomethylamine raw material into a reactor; adding heat conducting oil into the shell of the reactor to heat the raw materials so as to react the raw materials; and after the raw materials react for 2-6 hours, discharging the product from the reactor to a surplus reaction device for cyclic reaction, and discharging the raw materials for the next procedure after the reaction reaches a set standard. The reactor raw material adopts high-purity monomethylamine, reduces the water in the raw material, simultaneously makes the raw material fully react, and reduces the residual raw material in the sewage, thereby reducing the sewage discharge and the treatment cost.

Description

NMP synthesis process

Technical Field

The invention belongs to the technical field of chemical production, and particularly relates to a NMP synthesis process.

Background

The chemical name of NMP is N-methyl pyrrolidone (NMP), which is a high boiling point, environment-friendly and excellent solvent, and has the advantages of low viscosity, chemical stability, good performance and thermal stability, high polarity, low volatility, unlimited miscibility with water and a plurality of organic solvents, and the like. The market application field of the N-methyl pyrrolidone is mainly focused on industries such as lithium batteries, circuit boards, insulating materials, petrifaction, medicines, pesticides, cleaning, macromolecules and the like. NMP is produced mainly through ammonification reaction between GBL and monomethylamine.

The prior art CN202010960297.1 discloses a process for synthesizing NMP by adopting a solid strong acid catalyst, which comprises the following steps: preheating 1, 4-butanediol by a preheater and then feeding the preheated butanediol into a vaporizer for vaporization; the vaporized gas-phase material enters a heater to be heated, then enters a GBL reactor to react, and the temperature of 180-250 ℃ and the normal pressure condition are controlled under the action of a copper catalyst; the generated mixed gas of butyrolactone and hydrogen firstly passes through the heat exchanger and then enters the first-stage condenser and the second-stage condenser, part of hydrogen is evacuated, and part of hydrogen is sent to hydrogen circulation by the fan; and (3) condensing to obtain a gamma-butyrolactone crude product, directly feeding the gamma-butyrolactone crude product into an NMP reactor, and adding a methylamine solution and a solid strong acid catalyst to react to obtain the NMP crude product. The scheme can synthesize high-purity NMP, fully utilizes heat energy to achieve the effects of saving energy and reducing consumption, improves the utilization rate of resources, and has higher social use value and application prospect.

The scheme adopts methylamine liquid to increase the transportation cost of raw material purchase, and simultaneously, the sewage treatment capacity is 3.5 times of the theoretical reaction capacity, so that the sewage treatment capacity is increased, and the environmental pollution is increased.

Disclosure of Invention

The scheme provides an NMP synthesis process for reducing sewage treatment capacity.

In order to achieve the above object, the present invention provides a NMP synthesis process, comprising the following steps:

the method comprises the following steps: introducing a GBL raw material into a GBL elevated tank, and introducing a high-purity monomethylamine raw material into a monomethylamine elevated tank;

step two: feeding a GBL raw material with stable pressure into a static mixer from a GBL elevated tank, and feeding a high-purity monomethylamine raw material with stable pressure into the static mixer from a monomethylamine elevated tank;

step three: feeding the mixed GBL raw material and high-purity monomethylamine raw material into a reactor;

step four: adding heat conducting oil into the shell of the reactor to heat the raw materials so as to react the raw materials;

step five: and after the raw materials react for 2-6 hours, discharging the product from the reactor to a surplus reaction device for cyclic reaction, and discharging the raw materials for the next procedure after the reaction reaches a set standard.

Has the advantages that: the water in the raw materials is reduced by using the high-purity monomethylamine, so that the sewage treatment capacity and the raw material transportation cost after reaction are reduced; the raw materials are fully reacted through the residual reaction device, so that the residual raw materials in the sewage are reduced, and the sewage treatment capacity after reaction is reduced.

Further, the molar ratio of the high-purity monomethylamine feedstock to the GBL feedstock in the static mixer of step two is 1.06. The process proportion is optimized to 1.06 from the original 1.11, and the material loss is reduced.

Further, a monomethylamine metering pump and a GBL metering pump are adopted in the second step, so that the proportion of the high-purity monomethylamine raw material and the GBL raw material is higher. The proportion of the high-purity monomethylamine raw material and the GBL raw material can be accurately controlled.

Further, the temperature of the heat transfer oil in the third step is 255-280 ℃.

Further, the reactor in the third step comprises a coil pipe and a shell; the coil pipe is fixedly arranged in the shell; a gap is formed between the coil pipe and the shell; an oil inlet and an oil outlet are respectively arranged at two ends of the shell.

Furthermore, four oil inlets and four oil outlets are respectively arranged at two ends of the shell, so that the heat conduction oil can be rapidly filled and can uniformly flow in the tank body.

Further, the residual reaction device comprises a high-pressure buffer tank, a PLC (programmable logic controller) and a monomethylamine detector; the high-pressure buffer tank is communicated with the reactor coil; the high-pressure buffer tank is provided with an exhaust hole, and the exhaust hole is provided with an electric valve; the exhaust hole is communicated with an unqualified tank which is communicated with the static mixer; the monomethylamine detector is arranged at a feed inlet of the high-pressure buffer tank and is positioned in the high-pressure buffer tank; the PLC controller is fixedly arranged on the high-pressure buffer tank; and the PLC is electrically connected with the monomethylamine detector and the electric valve switch.

When the product in the coil pipe is discharged into the high-pressure buffer tank and the reaction is unqualified, a certain amount of monomethylamine remains in the high-pressure buffer tank, and when the monomethylamine detector detects that the concentration of the monomethylamine exceeds a set value, the PLC controller controls to open the electric valve, so that the reacted high-temperature gas is discharged into the unqualified tank and enters the static mixer again for reaction. When the concentration of the monomethylamine is lower than a set value, the PLC controller controls the electric valve to be closed. In the prior art, the product is judged to be qualified according to experience or is inspected when the product is finished, and the cost of the product is higher. Whether the finished product is qualified or not is detected by the monomethylamine detector, and the reaction is carried out again if the finished product is unqualified, so that the cost is saved, and the product yield is improved.

Further, a nitrogen inlet is arranged on the high-pressure buffer tank and communicated with a high-pressure nitrogen tank; the nitrogen inlet is communicated with a first branch pipe, and an outlet of the first branch pipe corresponds to a detection port of the monomethylamine detector; and a first electric valve is arranged in the first branch pipe, and a first electric valve switch is electrically connected with the PLC.

When the monomethylamine detector detects that the concentration of monomethylamine exceeds a set value, the PLC controller opens the first electric valve to open the first branch pipe, so that high-pressure nitrogen enters the high-pressure buffer tank from the first branch pipe, and high-pressure gas enables reaction products to completely enter the non-closed tank to prevent the products from remaining; the high-pressure gas can accelerate the reaction rate of the reaction product (for the chemical reaction with gas, when other conditions are unchanged (except volume), the pressure is increased, namely the volume is reduced, the concentration of the reactant is increased, the number of activated molecules in unit volume is increased, the effective collision times in unit time are increased, and the reaction rate is accelerated), so that the raw materials are fully reacted; meanwhile, the nitrogen washes the monomethylamine detector, so that monomethylamine is prevented from remaining on the monomethylamine detector, and the sensitivity of the monomethylamine detector is ensured.

Furthermore, the nitrogen inlet is communicated with a second branch pipe, and an outlet of the second branch pipe corresponds to a detection port of the monomethylamine detector; a second electric valve is arranged in the second branch pipe, and a switch of the second electric valve is electrically connected with the PLC; the first branch pipe and the second branch pipe are respectively positioned at two ends of a methylamine detector. When the monomethylamine detector detects that monomethylamine concentration exceeds a set value, the PLC controller is enabled to set time and intermittently switch to open the first electric valve or the second electric valve, nitrogen is enabled to flush the monomethylamine detector, the monomethylamine detector is cleaned more comprehensively, and sensitivity of the monomethylamine detector is guaranteed.

The scheme has the beneficial effects that: continuous production is realized, the capacity reaches tens of thousands of tons per year, and the method is suitable for large-scale industrial production; the sewage treatment capacity is reduced, the water content in the reactor product is 15 percent, which is 27 percent of the original technology, the production energy consumption is effectively reduced, the sewage discharge capacity is reduced, the requirements of national energy-saving and emission-reducing policies are met, and the environmental pollution is reduced; the raw material of the reactor adopts high-purity monomethylamine, so that the transportation cost of unit raw material is reduced, and the site selection of a factory is not limited; the process proportion is optimized to 1.06 from the original 1.11, and the material loss is reduced.

Drawings

Fig. 1 is a schematic structural diagram of an embodiment of the present invention.

Fig. 2 is a front view of a high pressure surge tank in an embodiment of the present invention.

Detailed Description

The following is further detailed by the specific embodiments:

reference numerals in the drawings of the specification include: the device comprises an electric valve 1, a nitrogen inlet pipe 2, a feeding pipe 3, a discharging pipe 4, a monomethylamine detector 5, a manhole 6, a hole cover 7, a GBL elevated tank 8, a monomethylamine elevated tank 9, a GBL metering pump 10, a monomethylamine metering pump 11, a static mixer 12, a reactor 13, an oil outlet 14, an oil inlet 15, an unqualified tank 16, a high-pressure nitrogen tank 17, a high-pressure buffer tank 18, a first branch pipe 19 and a second branch pipe 20.

Example (b):

the scheme discloses a device for realizing the synthesis process, which comprises the following steps:

as shown in attached figure 1, the synthetic production device for generating NMP by the reaction of GBL and high-purity monomethylamine comprises a GBL elevated tank 8, a monomethylamine elevated tank 9, a GBL metering pump 10, a monomethylamine metering pump 11 and a static mixer 12, wherein the GBL elevated tank 8 is communicated with the GBL metering pump 10, the monomethylamine elevated tank 9 is communicated with the monomethylamine metering pump 11, and the GBL metering pump 10 and the monomethylamine metering pump 11 are communicated with the static mixer 12. A methylamine mixer is arranged between the methylamine metering pump 11 and the static mixer 12; a GBL mixer is arranged between the GBL metering pump 10 and the static mixer 12; the monomethylamine mixer is used for providing stable materials for the monomethylamine metering pump 11 and can buffer the supply of system materials. The GBL mixer is used to stabilize the supply of material to the GBL metering pump 10 while providing a buffer effect on the supply of system material.

Reactor 13 includes coil pipe and casing, the coil pipe is fixed to be set up in the casing, there is the clearance between coil pipe and casing, coil pipe and static mixer 12 intercommunication, the casing is equipped with oil inlet 15 and oil-out 14, oil inlet 15 and oil-out 14 all communicate with coil pipe and casing clearance, the casing left end still is connected with four oil inlets 15, four oil inlets 15 are along the circumference equipartition of casing, the casing right-hand member is connected with four oil-out 14, four oil-out 14 are equally along the circumference equipartition of casing. The arrangement enables the heat conduction oil to be rapidly filled and to uniformly flow in the tank body. The coil is communicated with a high-pressure buffer tank 18.

As shown in the attached figure 2, a methylamine detector 5 and a PLC (programmable logic controller) are arranged on a high-pressure buffer tank 18, a feeding hole is formed in the side face of the bottom of the high-pressure buffer tank 18, and the feeding hole is communicated with a feeding pipe 3. The bottom of the high-pressure buffer tank 18 is provided with a discharge outlet which is communicated with a discharge pipe 4, and the discharge pipe 4 is provided with a control valve.

An exhaust hole is formed in the high-pressure buffer tank 18, an electric valve 1 is arranged at the exhaust hole, the exhaust hole is communicated with an unqualified tank 16, the unqualified tank 16 is communicated with the static mixer 12, the monomethylamine detector 5 is arranged at the feed inlet of the high-pressure buffer tank 18, the monomethylamine detector 5 is positioned in the high-pressure buffer tank 18, the model of the amine detector 5 is RBT-6000-ZLG, and the measurement range is 0-100 ppm. The PLC is electrically connected with the monomethylamine detector 5 and the switch of the electric valve 1. When the product in the coil pipe is discharged into the high-pressure buffer tank 18 and the reaction is unqualified, a certain amount of monomethylamine remains in the high-pressure buffer tank 18, and when the monomethylamine detector 5 detects that the concentration of the monomethylamine exceeds a set value, the PLC controller controls the opening of the electric valve 1, so that the reacted high-temperature gas is discharged into the unqualified tank and enters the static mixer 12 again for reaction. When the concentration of the monomethylamine is detected to be lower than the set value, the PLC controller controls the electric valve 1 to be closed. In the prior art, the product is judged to be qualified according to experience or is inspected when the product is finished, and the cost of the product is higher. Whether the finished product is qualified or not is detected by the monomethylamine detector 5, and the reaction is carried out again if the finished product is unqualified, so that the finished product is saved, and the product yield is improved.

Be equipped with the nitrogen gas air inlet on the high pressure buffer tank 18, nitrogen gas air inlet intercommunication has high-pressure nitrogen gas jar 17, nitrogen gas air inlet intercommunication has nitrogen gas intake pipe 2, nitrogen gas intake pipe 2 is located inside high

pressure buffer tank

18, 2 intercommunications of nitrogen gas intake pipe have first branch pipe 19 and second branch pipe 20, first branch pipe 19 is located methylamine detector 5 upper and lower ends respectively with

second branch pipe

20, 19 exports of first branch pipe and second branch pipe 20 all corresponding with methylamine detector 5 detection port, be equipped with first electric valve in the first branch pipe 19, first electric valve switch is connected with the PLC controller electricity. A second electric valve is arranged in the second branch pipe 20, and the switch of the second electric valve is electrically connected with the PLC.

When the monomethylamine detector 5 detects that the concentration of monomethylamine exceeds a set value, the PLC intermittently switches to open the first electric valve or the second electric valve within a set time, high-pressure nitrogen enters the high-pressure buffer tank 18 from the first branch pipe 19 or the second branch pipe 20 to flush the monomethylamine detector 5, and the first branch pipe 19 or the second branch pipe 20 is intermittently started to be opened to more completely clean the monomethylamine detector 5, so that the sensitivity of the monomethylamine detector 5 is ensured; the high-pressure nitrogen makes the reaction product completely enter the non-closed tank to prevent the product from remaining; the high-pressure nitrogen can accelerate the reaction rate of the reaction product (for the chemical reaction with gas, when other conditions are unchanged (except volume), the pressure is increased, namely the volume is reduced, the concentration of the reactant is increased, the number of activated molecules in unit volume is increased, the effective collision times in unit time are increased, and the reaction rate is accelerated), so that the raw materials are fully reacted.

Be equipped with manhole 6 on the 18 lower extreme lateral wall of high-pressure buffer tank, be equipped with handhole door 7 on the manhole 6, manhole 6 passes through bolt fixed connection with handhole door 7, and when manhole 6 was used for sharp superpressure or vacuum in the one-tenth jar, the prevention damaged the storage tank and the emergence accident, can play the safe back-fire relief effect again.

A process for synthesizing NMP, comprising the steps of:

the high-purity monomethylamine raw material and GBL raw material are mixed by adopting a monomethylamine metering pump and a GBL metering pump. The proportion of the high-purity monomethylamine raw material to the GBL raw material can be accurately controlled;

the molar ratio of high purity monomethylamine feed to GBL feed in the static mixer was 1.06. The process proportion is optimized to 1.06 from the original 1.11, so that the material loss is reduced;

step four: adding heat conducting oil into the shell of the reactor to heat the raw materials so as to react the raw materials; the temperature of the heat conducting oil is 255-280 ℃;

step five: after the raw materials react for 2-6 hours, discharging a product from the reactor; and discharging the product into a high-pressure buffer tank 18, detecting the concentration of the reaction product monomethylamine by a monomethylamine detector 5, and when the concentration of the monomethylamine exceeds a set value by 1ppm, controlling the reaction product to be discharged into an unqualified tank 16 from an exhaust hole of the high-pressure buffer tank 18 by a PLC (programmable logic controller), and entering a static mixer 12 again for circular reaction. And (5) repeating the step (5) until the concentration of the monomethylamine is lower than the set value by 1ppm, opening a control valve of a discharge pipe (4), and enabling the reaction product to enter the next working procedure from the discharge pipe (4).

The scheme realizes continuous production, has the capacity of tens of thousands of tons per year and accords with large-scale industrial production; the sewage treatment capacity is reduced, the water content in the reactor product is 15 percent, which is 27 percent of the original technology, the production energy consumption is effectively reduced, the sewage discharge capacity is reduced, the requirements of national energy-saving and emission-reducing policies are met, and the environmental pollution is reduced; the raw material of the reactor adopts high-purity monomethylamine, so that the transportation cost of unit raw material is reduced, and the site selection of a factory is not limited; the process proportion is optimized to 1.06 from the original 1.11, and the material loss is reduced.

The foregoing is merely an example of the present invention and common general knowledge of known specific structures and features of the embodiments is not described herein in any greater detail. It should be noted that, for those skilled in the art, without departing from the structure of the present invention, several changes and modifications can be made, which should also be regarded as the protection scope of the present invention, and these will not affect the effect of the implementation of the present invention and the practicability of the patent. The scope of the claims of the present application shall be determined by the contents of the claims, and the description of the embodiments and the like in the specification shall be used to explain the contents of the claims.

Claims

1. A process for synthesizing NMP, comprising the steps of:

the method comprises the following steps: introducing a GBL raw material into a GBL elevated tank (8), and introducing a high-purity monomethylamine raw material into a monomethylamine elevated tank (9);

step two: feeding a GBL feedstock at a stable pressure from a GBL head tank (8) to a static mixer (12), feeding a high purity monomethylamine feedstock at a stable pressure from a monomethylamine head tank (9) to the static mixer (12);

step three: feeding the mixed GBL raw material and high-purity monomethylamine raw material into a reactor (13);

step four: heat conducting oil is added into the shell of the reactor (13) to heat the raw materials, so that the raw materials react;

step five: and after the raw materials react for 2-6 hours, discharging the product from the reactor (13) to a surplus reaction device for circular reaction, and discharging the raw materials for the next procedure after the reaction reaches a set standard.

2. The process of claim 1 for the synthesis of NMP, wherein: the molar ratio of the high-purity monomethylamine raw material to the GBL raw material in the static mixer (12) in the second step is 1.06.

3. The process of claim 1 for the synthesis of NMP, wherein: and in the second step, a monomethylamine metering pump (11) and a GBL metering pump (10) are adopted to mix a high-purity monomethylamine raw material and a GBL raw material.

4. The process of claim 1 for the synthesis of NMP, wherein: the temperature of the heat conducting oil in the third step is 255-280 ℃.

5. The process of claim 1 for the synthesis of NMP, wherein: the reactor (13) in the third step comprises a coil and a shell; the coil pipe is fixedly arranged in the shell; a gap is formed between the coil pipe and the shell; an oil inlet (15) and an oil outlet (14) are respectively arranged at two ends of the shell.

6. The process of claim 5 for the synthesis of NMP, wherein: and two ends of the shell are respectively provided with four oil inlets (15) and four oil outlets (14).

7. The process of claim 5 for the synthesis of NMP, wherein: surplus reaction unit includes high-pressure buffer tank (18), PLC controller and monomethylamine detector (5), high-pressure buffer tank (18) and reactor (13) coil pipe intercommunication, be equipped with the exhaust hole on high-pressure buffer tank (18), exhaust hole department is equipped with electric valve (1), and the exhaust hole intercommunication has unqualified jar (16), and unqualified jar (16) and static mixer (12) intercommunication, monomethylamine detector (5) set up high-pressure buffer tank (18) feed inlet department, and monomethylamine detector (5) are located high-pressure buffer tank (18), the PLC controller is fixed to be set up on high-pressure buffer tank (18), the PLC controller is connected with monomethylamine detector (5) and the equal electricity of electric valve (1) switch.

8. The process of claim 7 for the synthesis of NMP, wherein: be equipped with the nitrogen gas air inlet on high pressure buffer tank (18), nitrogen gas air inlet intercommunication has high-pressure nitrogen gas jar (17), nitrogen gas air inlet intercommunication has first branch pipe (19), and first branch pipe (19) export is corresponding with methylamine detector (5) detection opening, be equipped with first electric valve in first branch pipe (19), first electric valve switch is connected with the PLC controller electricity.

9. The process of claim 8 for the synthesis of NMP, wherein: the nitrogen inlet intercommunication has second branch pipe (20), and second branch pipe (20) export is corresponding with methylamine detector (5) detection opening, the intraductal second electric valve that is equipped with of second branch pipe (20), second electric valve switch and PLC controller electricity are connected, first branch pipe (19) are located methylamine detector (5) both ends respectively with second branch pipe (20).