Short-process and low-carbon-emission N-methyl pyrrolidone industrial chain production process

Abstract

The invention provides a short-process and low-carbon-emission N-methyl pyrrolidone industrial chain production process, and the key point is that one-mixed methylamine and two-mixed methylamine react with gamma-butyrolactone raw materials to synthesize N-methyl pyrrolidone, so that not only is a methylamine separation tower saved, but also the problem that dimethylamine is difficult to take out can be solved; compared with similar devices, the production process flow is effectively shortened, the production cost of an N-methyl pyrrolidone industrial chain is greatly reduced, meanwhile, by-products brought by the production process are effectively recycled by means of the advantages of a chemical industry park, and carbon emission is greatly reduced; the N-methyl pyrrolidone product prepared by the preparation method disclosed by the invention is extremely competitive.

Description

Technical Field

[0001] The invention relates to the technical field of N-methylpyrrolidone, and in particular to a short-process, low-carbon emission N-methylpyrrolidone industrial chain production process. Background Art

[0002] N-methylpyrrolidone (NMP) is a nitrogen heterocyclic compound with a series of excellent physical and chemical properties. It is a non-toxic, high boiling point, strong polarity, low viscosity, low corrosiveness, high solubility, low volatility, good stability, and easy to recycle high-efficiency selective solvent. It is widely used in petrochemicals, high-precision electronics, circuit boards, lithium batteries and other fields. NMP is a very important auxiliary material for the production of lithium-ion battery electrodes. It is mainly used to dissolve / swell PVDF and dilute slurry. The quality of NMP products directly affects the production and quality of high-end electronic products.

[0003] At present, NMP is synthesized by the reaction of γ-butyrolactone (GBL) and methylamine. The methylamine raw material in the mainstream NMP production process is generally monomethylamine aqueous solution or monomethylamine. A large amount of wastewater needs to be treated during the production process using monomethylamine aqueous solution. The reaction temperature and pressure of monomethylamine are relatively high. The most important thing is that the monomethylamine raw material is synthesized from methanol and liquid ammonia. When producing monomethylamine, a large amount of dimethylamine is produced as a by-product. If there is no downstream supporting, dimethylamine needs to be sold out. At present, the domestic dimethylamine market is relatively sluggish. BASF's public patent uses mixed methylamine to synthesize NMP, but the reaction rates of monomethylamine, dimethylamine, trimethylamine and GBL are in a declining state. The reaction rate of trimethylamine is the slowest, and there is a risk of trimethylamine accumulation. In addition, the required reaction pressure and residence time will be longer, and the equipment investment is higher.

[0004] To this end, the prior art discloses a technical improvement for synthesizing NMP from mixed methylamines. For example, CN116283704A discloses a continuous preparation method for N-methylpyrrolidone, comprising: putting the raw materials into a first mixer and mixing them, and then entering a reaction tower I filled with a balanced catalyst through a heat exchanger; the generated monomethylamine, dimethylamine, and trimethylamine continuously flow from the bottom of the tower into a rectification tower I to remove the unreacted ammonia in the system, and the ammonia is removed as the first light component from the top of the rectification tower I, and the bottom distillate is the first heavy component, which flows into the reaction tower II, and the dimethylamine and trimethylamine in the reaction tower II undergo a hydrolysis reaction to generate monomethylamine; then the reaction tower flows into a second mixer, and after mixing with γ-butyrolactone in the second mixer, flows into the reaction tower III to carry out the N-methylpyrrolidone synthesis reaction; after the reaction is completed, the reaction tower enters the rectification tower II for rectification, and the second heavy component N-methylpyrrolidone crude product obtained in the bottom of the tower enters the rectification tower III for further purification, and the third light component at the top of the tower is N-methylpyrrolidone. Compared with directly using a monomethylamine solution, the raw material cost and processing cost are reduced; compared with using a mixed methylamine to directly react with γ-butyrolactone, the conversion rate of GBL can be better improved. However, the technical solution uses a mixed aqueous solution mainly containing monomethylamine as a raw material (the content of dimethylamine is 0-2wt%, the content of trimethylamine is 0-4wt%, and the water content is 30-50%), and then reacts with γ-butyrolactone to prepare N-methylpyrrolidone. The raw material utilization rate of the mixed methylamine, especially monomethylamine, is low, and the production cost is high.

[0005] Therefore, it is currently necessary to develop a new N-methylpyrrolidone industry chain production process to shorten the process, save production costs and reduce carbon emissions. Summary of the invention

[0006] In order to solve the technical problems of high production cost, difficulty in selling by-products and high carbon emissions in the NMP production process, the present invention provides a short-process, low-carbon emission N-methylpyrrolidone industry chain production process, which focuses on synthesizing N-methylpyrrolidone by reacting one or two mixed methylamines with γ-butyrolactone raw materials, which not only saves the methylamine separation tower, but also solves the problem of difficulty in selling dimethylamine, effectively shortens the production process, reduces carbon emissions, and reduces production costs.

[0007] To achieve this object, the present invention adopts the following technical solutions:

[0008] The present invention provides a short-process, low-carbon emission N-methylpyrrolidone industrial chain production process, the industrial chain production process comprising:

[0009] Methanol and liquid ammonia are mixed and heated to carry out methylamine synthesis reaction, and the obtained methylamine reaction product is successively subjected to deammoniation, water extraction, and dehydration to obtain a mixed methylamine, methanol waste liquid, and recycled water;

[0010] The mono-di-mixed methylamine and the γ-butyrolactone raw material are mixed and then cooled, and then pressurized and heated to carry out an N-methylpyrrolidone synthesis reaction, and the obtained N-methylpyrrolidone reaction product is subjected to demethylamine to obtain a liquid phase mixed amine and a crude N-methylpyrrolidone product, and the crude N-methylpyrrolidone is subjected to N-methylpyrrolidone refining to obtain a liquid phase heavy component and an N-methylpyrrolidone product.

[0011] The industrial chain production process of the present invention focuses on synthesizing N-methylpyrrolidone by reacting a mixed methylamine with a γ-butyrolactone raw material, which not only saves a methylamine separation tower, but also solves the problem that dimethylamine is difficult to sell out, effectively shortens the production process, reduces carbon emissions, and reduces production costs.

[0012] As a preferred technical solution of the present invention, the γ-butyrolactone raw material is obtained by the following preparation method:

[0013] 1,4-butanediol is mixed with circulating hydrogen and then preheated to carry out a γ-butyrolactone synthesis reaction. The obtained γ-butyrolactone reaction product is cooled to obtain a gas phase product and a liquid phase crude product; a part of the gas phase product is returned as the circulating hydrogen, and the other part is recycled; the liquid phase crude product is subjected to light component removal and refining to obtain light component impurities and the γ-butyrolactone raw material; wherein the light component impurities include tetrahydrofuran and butanol, and the γ-butyrolactone raw material contains γ-butyrolactone and heavy component impurities.

[0014] In the prior art, in the process of producing GBL by the BDO method, it is necessary to remove light and heavy components to obtain the GBL product, and the equipment investment and operating costs are high. The industrial chain production process of the present invention is based on the fact that the boiling point of GBL is close to that of NMP, and a γ-butyrolactone raw material containing γ-butyrolactone and heavy component impurities is used to carry out the N-methylpyrrolidone synthesis reaction. The heavy component impurities can enter the liquid phase heavy component during the refining process of N-methylpyrrolidone, thereby being removed, and will not affect the purity of the N-methylpyrrolidone product. Therefore, the industrial chain production process of the present invention cancels the GBL heavy component removal tower, effectively saves investment, and reduces operating costs.

[0015] As a preferred technical solution of the present invention, 1,4-butanediol (BDO) is mixed with preheated circulating hydrogen after high-pressure atomization, the hydrogen-to-alcohol ratio is controlled at 12 to 16, for example, 12, 12.5, 13, 13.5, 14, 14.5, 15, 15.5 or 16, and the pressure is controlled at 0.3 to 0.5 MPaG, for example, 0.3 MPaG, 0.35 MPaG, 0.4 MPaG, 0.45 MPaG or 0.5 MPaG.

[0016] Preferably, the reaction cold spot temperature of the γ-butyrolactone synthesis reaction is controlled at 180-210°C, such as 180°C, 185°C, 190°C, 195°C, 200°C, 205°C or 210°C.

[0017] The γ-butyrolactone synthesis reaction of the present invention adopts a tubular reactor, and the tubular reactor is filled with Wanhua's self-developed catalyst, see CN117599809A for details.

[0018] Preferably, the light removal refining is carried out using a GBL light removal tower, the tower top pressure is controlled at 10-15 KPaA, such as 10 KPaA, 11 KPaA, 12 KPaA, 13 KPaA, 14 KPaA or 15 KPaA, the tower top temperature is controlled at 75-90°C, such as 75°C, 80°C, 85°C or 90°C, the reflux ratio is controlled at 5.0-15.0, such as 5.0, 7.0, 8.0, 10.0, 11.0, 12.0, 13.0, 14.0, 15.0, etc. 1.0, 13.0 or 15.0, etc., the bottom temperature is controlled at 130-140°C, for example, 130°C, 131°C, 133°C, 135°C, 137°C, 138°C or 140°C, etc.; the liquid phase produced from the bottom of the tower is a γ-butyrolactone raw material containing γ-butyrolactone and heavy component impurities; the distillate from the top of the tower is the light component impurities, which is sent to the park for further recovery of tetrahydrofuran and butanol, and the non-condensable gas at the top of the tower is absorbed by the circulating liquid of the vacuum unit and then sent for incineration.

[0019] As a preferred technical solution of the present invention, the methylamine reaction product is deaminated to obtain an azeotrope and a deaminated heavy component; the deaminated heavy component is extracted with water as an extractant to obtain a mixed amine light component and a mixed amine aqueous solution; the mixed amine aqueous solution is dehydrated to obtain the mono- and di-mixed methylamines, methanol waste liquid and recycled water;

[0020] The azeotrope and the mixed amine light component are returned to the methylamine synthesis reaction and mixed with methanol and liquid ammonia as raw materials; a part of the recovered water is returned to the water extraction for use as an extractant, and the other part enters the park biochemical system.

[0021] The industrial chain production process of the present invention can not only recycle the separated impurity-containing streams, but also recycle the involved by-products by leveraging the advantages of the large platform of the industrial park, thereby realizing the supporting advantages of the industrial chain and significantly reducing production costs and carbon emissions.

[0022] As a preferred technical solution of the present invention, the methanol waste liquid enters a methanol recovery tower for treatment, the recovered methanol obtained at the top of the tower is returned to the methylamine synthesis reaction as raw material methanol, and the wastewater obtained at the bottom of the tower enters the park biochemical system;

[0023] Preferably, the pressure of the methanol recovery tower is controlled at 50-100 KPaG, such as 50 KPaG, 60 KPaG, 70 KPaG, 80 KPaG, 90 KPaG or 100 KPaG, etc., the tower top temperature is controlled at 60-80°C, such as 60°C, 65°C, 70°C, 75°C or 80°C, etc., the reflux ratio is controlled at 10.0-20.0, such as 10.0, 11.0, 13.0, 15.0, 17.0, 19.0 or 20.0, etc., and the tower bottom temperature is controlled at 110-115°C, such as 110°C, 111°C, 112°C, 113°C, 114°C or 115°C, etc. The top distillate of the methanol recovery tower is returned to the methylamine synthesis reaction as raw material methanol, and the non-condensable gas is sent to the tail gas absorption system to recover the mixed amine and methanol.

[0024] As a preferred technical solution of the present invention, after methanol and liquid ammonia are mixed, the pressure is increased to 2.6-3.2 MPaG, for example, 2.6 MPaG, 2.7 MPaG, 2.8 MPaG, 2.9 MPaG, 3.0 MPaG, 3.1 MPaG or 3.2 MPaG, and the like is heated to 320-360°C, for example, 320°C, 330°C, 340°C, 350°C or 360°C, etc.

[0025] Preferably, the feed N / C of the methylamine synthesis reaction is 1.2 to 2.2:1, for example, 1.2:1, 1.4:1, 1.6:1, 1.8:1, 2.0:1 or 2.2:1.

[0026] In the present invention, the feed N / C of the methylamine synthesis reaction refers to the molar ratio of nitrogen element to carbon element in the feed. When the mixed amine light component obtained by water extraction and the small part of di-mixed methylamine obtained by dehydration are returned to the methylamine synthesis reaction as mixed amines, and when the azeotrope obtained by deamination is returned to the methylamine synthesis reaction, the total feed N / C obtained after the four materials of methanol, liquid ammonia, mixed amine and azeotrope are mixed refers to the molar ratio of nitrogen element to carbon element in the total feed.

[0027] Preferably, the reaction temperature of the methylamine synthesis reaction is controlled at 390-420°C, for example, 390°C, 395°C, 400°C, 405°C, 410°C, 415°C or 420°C.

[0028] As a preferred technical solution of the present invention, the deamination is carried out by a deamination tower, the tower top pressure is controlled at 1.7-1.9 MPaG, such as 1.7 MPaG, 1.75 MPaG, 1.8 MPaG, 1.85 MPaG or 1.9 MPaG, etc., the tower top pressure is controlled at 45-50°C, such as 45°C, 46°C, 47°C, 48°C, 49°C or 50°C, etc., and the reflux ratio is controlled at 1.0-2. 0, for example, 1.0, 1.1, 1.3, 1.5, 1.7, 1.8 or 2.0, the bottom temperature is controlled at 115-125°C, for example, 115°C, 117°C, 118°C, 120°C, 121°C, 123°C or 125°C, the bottom liquid is extracted for water extraction; the non-condensable gas at the top of the tower is sent to the tail gas absorption system to recover ammonia and mixed amines, and the top distillate is returned to the methylamine synthesis reaction as an azeotrope.

[0029] As a preferred technical solution of the present invention, the water extraction is carried out using an extraction tower, the pressure of the extraction tower is controlled at 0.8-0.9 MPaG, such as 0.8 MPaG, 0.81 MPaG, 0.83 MPaG, 0.85 MPaG, 0.86 MPaG, 0.88 MPaG or 0.9 MPaG, etc., the volume of water as an extractant and the feed is controlled at 0.8-2:1, such as 0.8:1, 0.9:1, 1:1, 1.1:1, 1.3:1, 1.5:1, 1.6:1, 1.8:1 or 2:1, etc., the tower The top temperature is controlled at 78-84°C, for example, 78°C, 79°C, 80°C, 81°C, 82°C, 83°C or 84°C, the reflux ratio is controlled at 1.0-2.0, for example, 1.0, 1.1, 1.3, 1.5, 1.7, 1.9 or 2.0, the bottom temperature is controlled at 148-156°C, for example, 148°C, 150°C, 152°C, 154°C or 156°C, the bottom liquid phase is extracted for the dehydration; the top distillate is the light component of the mixed amine, which is returned to the methylamine synthesis reaction to participate in the reaction, and the top non-condensable gas is sent to the tail gas absorption system to recover the mixed amine.

[0030] As a preferred technical solution of the present invention, the dehydration is carried out using a dehydration tower, the pressure of the dehydration tower is controlled at 0.5-0.6 MPaG, such as 0.5 MPaG, 0.53 MPaG, 0.55 MPaG, 0.58 MPaG or 0.6 MPaG, etc., the top temperature is controlled at 50-56°C, such as 50°C, 51°C, 52°C, 53°C, 54°C, 55°C or 56°C, etc., the reflux ratio is controlled at 2.0-4.0, For example, 2.0, 2.5, 3.0, 3.5 or 4.0, the bottom temperature is controlled at 162-165°C, for example, 162°C, 163°C, 164°C or 165°C, the top distillate is mono- and di-mixed methylamines, the bottom liquid phase is recovered water, a side sampling port is opened near the bottom, the side sampling temperature is controlled at 150-160°C, for example, 150°C, 153°C, 155°C, 157°C or 160°C, and the side sampling waste liquid is methanol waste liquid.

[0031] It should be noted that most of the mono- and di-mixed methylamines obtained by dehydration can be extracted and sent to the N-methylpyrrolidone synthesis reaction, and a small part can be returned to the methylamine synthesis reaction, especially the returned small part of the mono- and di-mixed methylamines can be mixed with the mixed amine light component obtained by water extraction and used as a mixed amine stream to participate in the methylamine synthesis reaction; the non-condensable gas at the top of the dehydration tower is sent to the tail gas absorption system to recover the mixed amines; a part of the liquid phase extracted from the bottom of the tower is returned to the extraction tower for use as an extractant, and the rest is sent to the park biochemical system for treatment; the side-extracted waste liquid is methanol waste liquid, which is sent to a methanol recovery tower to recover methanol.

[0032] As a preferred technical solution of the present invention, the mono-dimixed methylamine and γ-butyrolactone raw materials are pressurized to 1-3MPaG, such as 1MPaG, 1.5MPaG, 2MPaG, 2.5MPaG or 3MpaG, etc., and enter the static mixer for mixing. After mixing, the materials are cooled to 70-100°C by cross heat exchange and circulating water cooler and sent to a feed buffer tank, such as 70°C, 80°C, 90°C or 100°C, etc. The residence time of the materials in the feed buffer tank is controlled at 0.5-1.5h, such as 0.5h, 0.8h, 1.0h, 1.1h, 1.3h or 1.5h, etc. The material from the feed buffer tank is pressurized to 13-15MPaG, such as 13MPaG, 13.5MPaG, 14MPaG, 14.5MPaG or 15MPaG, etc. by a high-pressure pump to carry out the N-methylpyrrolidone synthesis reaction.

[0033] As a preferred technical solution of the present invention, in the N-methylpyrrolidone synthesis reaction, the mass ratio of the mono-dimixed methylamine and the γ-butyrolactone raw material is controlled at (0.447-0.481):1, for example, 0.447:1, 0.450:1, 0.455:1, 0.460:1, 0.465:1, 0.470:1, 0.475:1 or 0.481:1, etc.

[0034] Preferably, the reaction temperature of the N-methylpyrrolidone synthesis reaction is controlled at 340-360°C, such as 340°C, 345°C, 350°C, 355°C or 360°C, and the residence time is controlled at 0.5-2h, such as 0.5h, 1h, 1.5h or 2h.

[0035] As a preferred technical solution of the present invention, the demethylamine is carried out using a demethylamine tower, the tower top pressure is controlled at 15-20 KPaA, such as 15 MPaA, 16 MPaA, 17 MPaA, 18 MPaA, 19 MPaA or 20 MPaA, the tower top temperature is controlled at 58-62°C, such as 58°C, 59°C, 60°C, 61°C or 62°C, the reflux ratio is controlled at 0.8-1.5, such as 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4 or 1.5, the tower bottom temperature is controlled at 135-150°C, such as 135°C, 140°C, 145°C or 150°C, the tower top distillate is the liquid phase mixed amine, the tower bottom liquid phase is the crude N-methylpyrrolidone, and the non-condensable gas at the top of the tower is sent for incineration through a vacuum unit.

[0036] As a preferred technical solution of the present invention, the N-methylpyrrolidone is purified by an NMP product tower, the tower top pressure is controlled at 4-6 KPaA, such as 4 KPaA, 4.5 KPaA, 5 KPaA, 5.5 KPaA or 6 KPaA, the tower top temperature is controlled at 95-105°C, such as 95°C, 97°C, 100°C, 101°C, 103°C or 105°C, the reflux ratio is controlled at 1.5-3.0, such as 1.5, 1.8, 2.0, 2.1, 2.3, 2.5, 2.7 or 3.0, the tower bottom temperature is controlled at 110-130°C, such as 110°C, 115°C, 120°C, 125°C or 130°C, the tower top distillate is the N-methylpyrrolidone product, the tower bottom liquid phase is the liquid phase heavy component, and the tower top non-condensable gas is sent for incineration through a vacuum unit.

[0037] As a preferred technical solution of the present invention, the liquid phase is recombined and sent to an NMP scraper film evaporator, the operating pressure of the NMP scraper film evaporator is controlled to be consistent with that of the NMP product tower, the recovered NMP is sent to a feed buffer tank, and the kettle residue is heated at 70-100° C. and sent to the park for further recovery of BDO; wherein, the NMP scraper film evaporator controls the purity of the kettle residue NMP to 40-60% by the evaporation temperature, for example, 40%, 45%, 50%, 55% or 60%, and the evaporation temperature is controlled at 110-140° C., for example, 110° C., 120° C., 130° C. or 140° C.

[0038] It should be noted that the non-condensable gases at the top of the deamination tower, extraction tower, dehydration tower and methanol recovery tower of the present invention are respectively sent to the tail gas absorption system, the tail gas absorption system is a packed absorption tower, fresh methanol is used as the absorbent, the absorption temperature is controlled at 15-25°C, and the methanol after absorbing the tail gas is sent to methylamine synthesis.

[0039] Compared with the prior art solutions, the present invention has at least the following beneficial effects:

[0040] (1) The short-process, low-carbon emission N-methylpyrrolidone industrial chain production process of the present invention focuses on synthesizing N-methylpyrrolidone by reacting a di-mixed methylamine with a γ-butyrolactone raw material, which not only saves a methylamine separation tower, but also solves the problem of the difficulty of selling dimethylamine. Compared with similar devices, the production process is effectively shortened, and the production cost of the N-methylpyrrolidone industrial chain is greatly reduced. At the same time, the by-products brought by the production process are effectively recycled and utilized with the advantages of the chemical park, which greatly reduces carbon emissions. The N-methylpyrrolidone product prepared by the present invention is very competitive.

[0041] (2) The short-process, low-carbon emission N-methylpyrrolidone industrial chain production process of the present invention adopts a mixed methylamine to synthesize NMP, which solves the problem that the byproduct dimethylamine is difficult to sell out, shortens the methylamine production process, and reduces the investment cost and production cost of methylamine;

[0042] (3) The short-process, low-carbon emission N-methylpyrrolidone industrial chain production process of the present invention directly uses the γ-butyrolactone raw material containing γ-butyrolactone and heavy component impurities to carry out the NMP synthesis reaction, eliminates the deweighting tower, shortens the GBL production process, and reduces the GBL investment cost and production cost;

[0043] (4) The short-process, low-carbon emission N-methylpyrrolidone industrial chain production process described in the present invention utilizes the advantages of the NMP industrial chain to recycle by-products such as methanol, tetrahydrofuran and butanol, thereby significantly reducing carbon emissions, while reducing NMP production costs and improving the competitiveness of NMP products. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 It is a process flow chart of the production process of the industrial chain described in the present invention;

[0045] Figure 2 This is a process flow chart of methylamine synthesis in the industrial chain production process described in Example 1 of the present invention;

[0046] Figure 3 This is a process flow chart of methylamine refining in the industrial chain production process described in Example 1 of the present invention;

[0047] Figure 4is a process flow chart of GBL synthesis in the industrial chain production process described in Example 1 of the present invention;

[0048] Figure 5 It is a process flow chart of GBL refining in the industrial chain production process described in Example 1 of the present invention;

[0049] Figure 6 It is a process flow chart of NMP synthesis in the industrial chain production process described in Example 1 of the present invention;

[0050] Figure 7 It is a process flow chart of NMP refining in the industrial chain production process described in Example 1 of the present invention;

[0051] In the figure: 1, methanol tank; 2, liquid ammonia tank; 3, mixed amine tank; 4, azeotrope tank; 5, methanol booster pump; 6, liquid ammonia booster pump; 7, mixed amine booster pump; 8, azeotrope booster pump; 9, methylamine feed static mixer; 10, low temperature heat exchanger; 11, steam preheater; 12, high temperature heat exchanger; 13, electric heater; 14, methylamine synthesis tower; 15, synthesis liquid separation tank; 16, deamination tower; 17, deamination tower top condenser; 18, azeotrope reflux tank; 19, deamination tower reboiler; 20, extraction tower; 21, extraction tower top condenser; 22, trimethylamine reflux tank; 23, extraction tower reboiler; 24, dehydration tower; 25, Dehydration tower top condenser; 26, methylamine reflux tank; 27, dehydration tower reboiler; 28, methanol recovery tower; 29, methanol recovery tower top condenser; 30, methanol reflux tank; 31, methanol recovery tower reboiler; 32, extraction water heat exchanger; 33, wastewater heat exchanger; 34, tail gas absorption tower; 35, tail gas absorption tower kettle external pump; 36, BDO raw material tank; 37, BDO booster pump; 38, mixing ejector; 39, vaporizer; 40, superheater; 41, GBL reactor; 42, GBL heat exchanger; 43, circulating water cooler; 44, crude GBL tank; 45, circulating hydrogen compressor; 46, external hydrogen compressor; 47, crude GBL delivery pump; 48, GBL light component removal tower; 49, GBL light component removal tower top condenser; 50, GBL light component reflux tank; 51, GBL light component reflux pump; 52, GBL light component removal tower kettle circulation pump; 53, GBL light component removal tower reboiler; 54, GBL product heat exchanger; 55, GBL raw material tank; 56, mixed amine raw material tank; 57, GBL booster pump; 58, mixed amine booster pump; 59, NMP feed static mixer; 60, NMP heat exchanger; 61, circulating water cooler; 62, feed buffer tank; 63, high pressure pump; 64, steam preheater; 65, NMP reactor; 66, crude NMP flash tank; 67, demethylamine tower; 68, demethylamine tower top condenser; 69, NMP light component reflux tank; 70, NMP light component reflux pump; 71, demethylamine tower bottom circulation pump; 72, demethylamine tower reboiler; 73, NMP product tower; 74, NMP product tower top condenser; 75, NMP product reflux tank; 76, NMP product reflux pump; 77, NMP product tower reboiler; 78, NMP product tower bottom circulation pump; 79, scraped film evaporator; 80, methylamine recovery tower; 81, methylamine recovery tower top condenser; 82, methylamine reflux tank; 83, methylamine reflux pump; 84, methylamine recovery tower reboiler. DETAILED DESCRIPTION

[0052] The technical solution of the present invention is further described below with reference to the accompanying drawings and through specific implementation methods.

[0053] The present invention provides a short-process, low-carbon emission N-methylpyrrolidone industry chain production process, such as Figure 1As shown, the production process of the industrial chain includes:

[0054] Methanol, liquid ammonia, mixed amines and azeotropes are mixed and heated to carry out methylamine synthesis reaction, and the obtained methylamine reaction product is deaminated to obtain azeotropes and deaminated heavy components; the azeotropes are returned to the methylamine synthesis reaction, and the deaminated heavy components are extracted with water using water as an extractant to obtain mixed amine light components and mixed amine aqueous solution; the mixed amine light components are returned to the methylamine synthesis reaction as mixed amine raw materials, and the mixed amine aqueous solution is dehydrated to obtain mono-dimixed methylamine, methanol waste liquid and recycled water; a part of the recycled water is returned to the water extraction for use as an extractant, and the other part enters the park biochemical system;

[0055] The mono-di-mixed methylamine and the γ-butyrolactone raw material are mixed and then cooled to perform an N-methylpyrrolidone synthesis reaction, and the obtained N-methylpyrrolidone reaction product is subjected to demethylamine to obtain a liquid phase mixed amine and a crude N-methylpyrrolidone product, and the crude N-methylpyrrolidone product is subjected to N-methylpyrrolidone refining to obtain a liquid phase heavy component and an N-methylpyrrolidone product.

[0056] To better illustrate the present invention and facilitate understanding of the technical solution of the present invention, typical but non-limiting embodiments of the present invention are as follows:

[0057] Example 1

[0058] This embodiment provides a short-process, low-carbon emission N-methylpyrrolidone industrial chain production process, the industrial chain production process comprising:

[0059] (1) Methylamine synthesis:

[0060] See also Figure 2 , methanol, liquid ammonia, mixed amine (extraction tower 20 overhead distillate, and a small part of the dehydration tower 24 overhead distillate, that is, a small part of mono-dimixed methylamine), azeotrope (deammoniation tower 16 overhead distillate) four materials are pressurized to 3.0MPaG from methanol tank 1, liquid ammonia tank 2, mixed amine tank 3, and azeotrope tank 4 by methanol pressure pump 5, liquid ammonia pressure pump 6, mixed amine pressure pump 7, and azeotrope pressure pump 8, respectively, and the feed N / C is controlled at 1.8:1, and the obtained pressurized materials are sent to methylamine feed static mixer 9 for mixing , and then heat exchange with the outlet hot stream of the methylamine synthesis tower 14 in the low-temperature heat exchanger 10 and the high-temperature heat exchanger 12. During normal start-up, the steam preheater 11 is not used. Then, it is heated to 350°C by the electric heater 13 and sent to the methylamine synthesis tower 14; the hot spot temperature of the methylamine synthesis tower 14 is controlled at 400°C, and the outlet hot stream and the inlet cold stream are heat exchanged in the high-temperature heat exchanger 12 and the low-temperature heat exchanger 10, and then cooled to 80°C, and separated by gas and liquid through the gas-liquid separation tank 15, and the gas-phase and liquid-phase mixed methylamine are sent to the deamination tower 16;

[0061] (2) Methylamine refining:

[0062] See also Figure 3 , the gas phase and liquid phase mixed methylamine are sent to the deamination tower 16, the tower top pressure is controlled at 1.7MPaG, the tower top temperature is controlled at 45°C, the reflux ratio is controlled at 1.2, the tower top gas phase passes through the deamination tower top condenser 17, and the distillate cooled into the liquid phase flows to the azeotrope reflux tank 18, a part of the distillate returns to the deamination tower 16, and the other part of the distillate is produced and returned to the azeotrope tank 4 of the methylamine synthesis system, and the non-condensable gas goes to the tail gas absorption tower 34 to recover ammonia and mixed amines; the tower bottom temperature is controlled at 118°C, and is heated by the deamination tower reboiler 19, and the tower bottom produced liquid phase is sent to the extraction tower 20;

[0063] The pressure of the extraction tower 20 is controlled at 0.8 MPaG, the volume ratio of extraction water to feed is controlled at 1.5, the tower top temperature is controlled at 79° C., the reflux ratio is controlled at 1.1, the tower top gas phase passes through the extraction tower top condenser 21, and the distillate cooled into the liquid phase flows to the trimethylamine reflux tank 22, a part of the distillate returns to the extraction tower 20, and the other part of the distillate is produced and returned to the mixed amine tank 3 of the methylamine synthesis system, and the non-condensable gas is sent to the tail gas absorption tower 34 to recover the mixed amine; the tower bottom temperature is controlled at 149° C., and it is heated by the extraction tower reboiler 23, and the tower bottom produced liquid phase is sent to the dehydration tower 24;

[0064] The pressure of the dehydration tower 24 is controlled at 0.6MPaG, the tower top temperature is controlled at 55°C, and the reflux ratio is controlled at 2.2. The tower top gas phase passes through the dehydration tower top condenser 25, and the distillate cooled into the liquid phase flows to the first and second mixed methylamine reflux tanks 26. A part of the distillate returns to the dehydration tower 24, and a part of the distillate is produced and returned to the mixed amine tank 3 of the methylamine synthesis system. Most of the distillate is sent to the mixed amine raw material tank 56 of the NMP synthesis system, and the non-condensable gas is sent to the tail gas absorption tower 34 to recover the mixed amine; the tower bottom temperature is controlled at 165°C, and is heated by the dehydration tower reboiler 27. A part of the tower bottom produced liquid phase is returned to the extraction tower 20 as extraction water after heat exchange in the extraction water heat exchanger 32, and the rest of the tower bottom produced liquid phase is sent to the park biochemical system for treatment after heat exchange in the wastewater heat exchanger 33. A side sampling port is added near the tower bottom, and the side sampling temperature is controlled at 158°C. The side sampling waste liquid is sent to the methanol recovery tower 28 to recover methanol;

[0065] The pressure of the methanol recovery tower is controlled at 80KPaG, the tower top temperature is controlled at 65°C, and the reflux ratio is controlled at 11.0. The tower top gas phase passes through the methanol recovery tower top condenser 29, and the distillate cooled into the liquid phase flows to the methanol reflux tank 30. A part of the distillate returns to the methanol recovery tower 28, and the other part of the distillate is produced and returned to the methanol tank 1 of the methylamine synthesis system. The non-condensable gas is sent to the tail gas absorption tower 34 to recover the mixed amine and methanol; the tower bottom temperature is controlled at 113°C, and it is heated by the methanol recovery tower reboiler 31. The tower bottom produced liquid phase is combined with the wastewater of the dehydration tower 24, and after heat exchange in the wastewater heat exchanger 33, it is sent to the park biochemical system for treatment;

[0066] See also Figure 3 In the dotted frame part, the non-condensable gas at the top of the deamination tower 16, the extraction tower 20, the dehydration tower 24, and the methanol recovery tower 28 is sent to the tail gas absorption tower 34 for recovery, and the tail gas absorption tower 34 is a packed absorption tower, using fresh methanol as an absorbent, and the absorption temperature is controlled at 18°C. The methanol after absorbing the tail gas is sent to the methanol tank 1 of the methylamine synthesis system through the tail gas absorption tower kettle external pump 35;

[0067] (3) GBL synthesis:

[0068] See also Figure 4 , 1,4-butanediol in the BDO raw material tank 36 is transported to the mixing ejector 38 for atomization through the BDO booster pump 37, and mixed with the circulating hydrogen preheated by the GBL heat exchanger 42, the hydrogen-to-alcohol ratio is controlled at 14, the pressure is controlled at 0.3 MPaG, and after mixing, it is preheated in two stages by the vaporizer 39 and the superheater 40 and sent to the GBL reactor 41. The GBL reactor 41 is a shell-and-tube reactor, and the shell-and-tube is filled with Wanhua's self-developed catalyst. The reaction cold point temperature is controlled at 185°C. The hot stream at the outlet of the GBL reactor 41 exchanges heat with the circulating hydrogen in the GBL heat exchanger 42, and then continues to be cooled by the circulating water cooler 43. Most of the gas phase obtained by cooling is pressurized and returned as circulating hydrogen through the circulating hydrogen compressor 45, and a small part is pressurized by the external hydrogen compressor 46 and sent to the washing tower for further use in the park. The liquid phase obtained by cooling is the GBL crude product, which is sent to the GBL light removal tower 48 through the crude GBL delivery pump 47;

[0069] (4) GBL refining:

[0070] See also Figure 5 , the GBL crude product is sent to the GBL light component removal tower 48, the tower top pressure is controlled at 12KPaA, the tower top temperature is controlled at 80°C, the reflux ratio is controlled at 7.0, the tower top gas phase passes through the GBL light component removal tower top condenser 49, and the distillate cooled into the liquid phase flows to the GBL light component reflux tank 50, and passes through the GBL light component reflux pump 51. A part of the distillate returns to the GBL light component removal tower 48, and a part of the liquid phase is produced and sent to the park for further recovery of tetrahydrofuran (THF) and butanol. The non-condensable gas is absorbed by the circulating liquid of the vacuum unit and then sent for incineration treatment. The tower bottom temperature is controlled at 134°C, and the tower bottom material is produced by the GBL light component removal tower bottom circulating pump 52. A part of it is heated by the GBL light component removal tower reboiler 53 and returned to the GBL light component removal tower 48, and the other part is sent to the GBL raw material tank 55 of the NMP synthesis system after heat exchange through the GBL product heat exchanger 54;

[0071] (5) NMP synthesis:

[0072] See also Figure 6The raw materials in the GBL raw material tank 55 and the mixed methylamine tank 56 are pressurized to 1.6 MPaG by the GBL booster pump 57 and the mixed amine booster pump 58 respectively, and enter the NMP static mixer 59 for mixing. The mass ratio of the mono-di-mixed methylamine and GBL is controlled at 0.465:1. The mixed materials are heat exchanged with the materials in the feed buffer tank 62 by the NMP material heat exchanger 60, and then cooled to 85°C by the circulating water cooler 61 and sent to the feed buffer tank 62. The residence time of the materials in the feed buffer tank 62 is controlled to be 1 hour. The materials are pressurized to 13.9 MPaG by the high-pressure pump 63, and are sent to the NMP reactor 65 after heat exchange by the NMP material heat exchanger 60 and heating by the steam preheater 64. The reaction temperature of the NMP reactor 65 is controlled at 355°C by heat transfer oil, and the residence time is controlled at 2 hours. The crude NMP product generated by the reaction enters the crude NMP flash tank 66 for flash evaporation, and the gas phase materials and liquid phase materials are sent to the demethylamine tower 67;

[0073] (6) NMP refining:

[0074] See also Figure 7 , the crude NMP product is sent to the demethylamine tower 67, the tower top pressure is controlled at 20KPaA, the tower top temperature is controlled at 62°C, the reflux ratio is controlled at 1.0, the tower top gas phase passes through the demethylamine tower top condenser 68, and the distillate cooled into the liquid phase flows to the NMP light component reflux tank 69, and passes through the NMP light component reflux pump 70. A part of the distillate returns to the demethylamine tower 67, and the other part of the distillate is produced and sent to the methylamine recovery tower 80 for simple removal of methanol and water. The top non-condensable gas of the demethylamine tower 67 is absorbed by the circulating liquid of the vacuum unit and then sent to incineration treatment; the tower bottom liquid phase of the demethylamine tower 67 is pressurized by the demethylamine tower bottom circulating pump 71, and a part of it is heated by the demethylamine tower reboiler 72, and the tower bottom temperature is controlled at 150°C, and the other part is produced and sent to the NMP product tower 73;

[0075] The pressure of the NMP product tower 73 is controlled at 4KPaA, the tower top temperature is controlled at 95°C, the reflux ratio is controlled at 1.8, the tower top gas phase passes through the NMP product tower top condenser 74, and the distillate cooled into the liquid phase flows to the NMP product reflux tank 75, and passes through the NMP product reflux pump 76. A part of the distillate returns to the NMP product tower 73, and the other part of the distillate is extracted as the NMP product; if the analysis is qualified, it is directly sent to the NMP product tank for collection, and if the analysis is unqualified, it is sent to the feed buffer tank 62, and the non-condensable gas is absorbed by the circulating liquid of the vacuum unit and then sent for incineration; the tower bottom extracted liquid The phase is pressurized by the NMP product tower bottom circulation pump 78, a part of it is heated by the NMP product tower reboiler 77 and returned to the NMP product tower 73, the tower bottom temperature is controlled at 130°C, and the other part is extracted and sent to the scraped film evaporator 79. The operating pressure of the scraped film evaporator 79 is consistent with that of the NMP product tower 73. The scraped film evaporator 79 controls the purity of the NMP in the bottom liquid of the kettle to 50% by the evaporation temperature, and the evaporation temperature is controlled at 120°C. The recovered NMP is sent to the feed buffer tank 62, and the bottom liquid of the kettle is heated at 70-100°C and sent to the park for further recovery of BDO.

[0076] The top gas phase of the methylamine recovery tower 80 passes through the methylamine recovery tower top condenser 81, and the distillate cooled into the liquid phase flows to the methylamine reflux tank 82. After being pressurized by the methylamine reflux pump 83, a part of it returns to the methylamine recovery tower 80, and the other part is sent to the deamination tower 16 for further refining, and the non-condensable gas is absorbed by the circulating liquid of the vacuum unit and then sent for incineration treatment; the liquid phase is extracted from the bottom of the methylamine recovery tower 80, a part of it is heated by the methylamine recovery tower reboiler 84, and the other part is sent to the methanol recovery tower 28 to recover methanol after mixing with the methanol waste liquid.

[0077] It should be noted that steps (1) and (2) have a sequence, methylamine synthesis and methylamine purification are carried out in sequence, and steps (3) and (4) have a sequence, GBL synthesis and GBL purification are carried out in sequence, but there is no sequence between steps (1) and (3).

[0078] In this example, the purity, reaction yield and key impurity content of the mono- and di-mixed methylamines obtained in steps (1) and (2) were characterized, the purity, reaction yield and key impurity content of the light-free GBL (i.e., the γ-butyrolactone raw material containing γ-butyrolactone and heavy component impurities) obtained in steps (3) and (4) were characterized, and the purity, reaction yield and key impurity content of the NMP product obtained in steps (5) and (6) were characterized. The specific characterization results are shown in Table 1.

[0079] Table 1

[0080]

[0081] Comparative Example 1

[0082] This comparative example provides a production process of N-methylpyrrolidone industry chain, which is different from Example 1 only in that: in step (2) methylamine refining, the bottom produced liquid of the deamination tower 16 is sent to a distillation tower to separate methanol, and the separated mixed amine is directly sent to the mixed amine raw material tank 56 of the NMP synthesis system to be directly used as the mixed amine raw material for the NMP synthesis reaction. It should be noted that because the bottom liquid of the deamination tower contains more water and methanol, in order to deduct the influence of water and methanol, the mass ratio of one, two and three mixed methylamines to GBL is increased to 0.626:1.

[0083] In this comparative example, the purity, reaction yield and key impurity content of the mono-, di- and tri-mixed methylamines obtained in steps (1) and (2) were characterized, the purity, reaction yield and key impurity content of the light-free GBL (i.e., the γ-butyrolactone raw material containing γ-butyrolactone and heavy component impurities) obtained in steps (3) and (4) were characterized, and the purity, reaction yield and key impurity content of the NMP product obtained in steps (5) and (6) were characterized. The specific characterization results are shown in Table 2.

[0084] Table 2

[0085]

[0086] Comparing Example 1 with Comparative Example 1, it can be seen that the reaction rate of trimethylamine and GBL is slow, resulting in more GBL residues in the reaction product. Since GBL has a similar boiling point to NMP, almost all of it is transferred to the NMP product, resulting in a decrease in the purity of the NMP product, which cannot meet the electronic grade requirements.

[0087] The invention provides a short-process, low-carbon emission N-methylpyrrolidone industrial chain production process, which focuses on synthesizing N-methylpyrrolidone by reacting a mono-di-mixed methylamine with a γ-butyrolactone raw material, which not only saves a methylamine separation tower, but also solves the problem that dimethylamine is difficult to sell out; further, a γ-butyrolactone raw material containing γ-butyrolactone and heavy component impurities is directly used for NMP synthesis reaction, the deweighting tower is cancelled, the GBL production process is shortened, and the GBL investment cost and production cost are reduced; moreover, by-products such as methanol, tetrahydrofuran and butanol are recovered by taking advantage of the NMP industrial chain, which greatly reduces carbon emissions, reduces the NMP production cost, and improves the competitiveness of NMP products; compared with similar devices, the production process is effectively shortened, the production cost of the N-methylpyrrolidone industrial chain is greatly reduced, and the by-products brought by the production process are effectively recycled and utilized by taking advantage of the chemical park, which greatly reduces carbon emissions; the N-methylpyrrolidone product prepared by the invention is very competitive.

[0088] The present invention illustrates the detailed structural features of the present invention through the above embodiments, but the present invention is not limited to the above detailed structural features, that is, it does not mean that the present invention must rely on the above detailed structural features to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of the components selected by the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

[0089] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, a variety of simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to the protection scope of the present invention.

[0090] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction, subject to the control to avoid unnecessary repetition, and the present invention will not further explain various possible combinations.

[0091] In addition, the various embodiments of the present invention may be arbitrarily combined, as long as they do not violate the concept of the present invention, and they should also be controlled by the contents disclosed in the present invention.

Claims

1. A short-process, low-carbon emission N-methylpyrrolidone industry chain production process, characterized in that: The production process of the industrial chain includes: Methanol and liquid ammonia are mixed and heated to carry out methylamine synthesis reaction, and the obtained methylamine reaction product is successively subjected to deammoniation, water extraction, and dehydration to obtain a mixed methylamine, methanol waste liquid, and recycled water; The mono-di-mixed methylamine and the γ-butyrolactone raw material are mixed and then cooled, and then pressurized and heated to carry out an N-methylpyrrolidone synthesis reaction, and the obtained N-methylpyrrolidone reaction product is subjected to demethylamine to obtain a liquid phase mixed amine and a crude N-methylpyrrolidone product, and the crude N-methylpyrrolidone is subjected to N-methylpyrrolidone refining to obtain a liquid phase heavy component and an N-methylpyrrolidone product.

2. The industrial chain production process according to claim 1, characterized in that: The γ-butyrolactone raw material is obtained by the following preparation method: 1,4-butanediol is mixed with circulating hydrogen and then preheated to carry out a γ-butyrolactone synthesis reaction. The obtained γ-butyrolactone reaction product is cooled to obtain a gas phase product and a liquid phase crude product; a part of the gas phase product is returned as the circulating hydrogen, and the other part is recycled; the liquid phase crude product is subjected to light component removal and refining to obtain light component impurities and the γ-butyrolactone raw material; wherein the light component impurities include tetrahydrofuran and butanol, and the γ-butyrolactone raw material contains γ-butyrolactone and heavy component impurities.

3. The industrial chain production process according to claim 2, characterized in that: 1,4-Butanediol is atomized at high pressure and mixed with preheated circulating hydrogen, the hydrogen-to-alcohol ratio is controlled at 12-16, and the pressure is controlled at 0.3-0.5MPaG; Preferably, the reaction cold spot temperature of the γ-butyrolactone synthesis reaction is controlled at 180-210°C; Preferably, the light removal and refining is carried out using a GBL light removal tower, the tower top pressure is controlled at 10-15 KPaA, the tower top temperature is controlled at 75-90°C, the reflux ratio is controlled at 5.0-15.0, and the tower bottom temperature is controlled at 130-140°C; the tower bottom produced liquid phase is a γ-butyrolactone raw material containing γ-butyrolactone and heavy component impurities; the tower top distillate is the light component impurities, which is sent to the park for further recovery of tetrahydrofuran and butanol.

4. The industrial chain production process according to any one of claims 1 to 3, characterized in that: The methylamine reaction product is deaminated to obtain an azeotrope and a deaminated heavy component; the deaminated heavy component is extracted with water as an extractant to obtain a mixed amine light component and a mixed amine aqueous solution; the mixed amine aqueous solution is dehydrated to obtain the mono- and di-mixed methylamines, methanol waste liquid and recycled water; The azeotrope and the mixed amine light component are returned to the methylamine synthesis reaction and mixed with methanol and liquid ammonia as raw materials; a part of the recovered water is returned to the water extraction for use as an extractant, and the other part enters the park biochemical system.

5. The industrial chain production process according to any one of claims 1 to 3, characterized in that: The methanol waste liquid enters the methanol recovery tower for treatment, the recovered methanol obtained at the top of the tower is returned to the methylamine synthesis reaction as raw material methanol, and the wastewater obtained at the bottom of the tower enters the park biochemical system; Preferably, the pressure of the methanol recovery tower is controlled at 50-100 KPaG, the tower top temperature is controlled at 60-80°C, the reflux ratio is controlled at 10.0-20.0, and the tower bottom temperature is controlled at 110-115°C.

6. The industrial chain production process according to any one of claims 1 to 3, characterized in that: After mixing methanol and liquid ammonia, pressurize to 2.6-3.2MPaG and heat to 320-360℃; Preferably, the feed N / C of the methylamine synthesis reaction is 1.2 to 2.2:1; Preferably, the reaction temperature of the methylamine synthesis reaction is controlled at 390-420°C.

7. The industrial chain production process according to any one of claims 1 to 3, characterized in that: The mono-di-mixed methylamine and γ-butyrolactone raw materials are pressurized to 1-3 MPaG respectively and enter into a static mixer for mixing. After mixing, the materials are cooled to 70-100° C. and sent to a feed buffer tank. The residence time of the materials in the feed buffer tank is controlled to be 0.5-1.5 h. The materials from the feed buffer tank are pressurized to 13-15 MPaG to carry out the N-methylpyrrolidone synthesis reaction.

8. The industrial chain production process according to claim 7, characterized in that: In the N-methylpyrrolidone synthesis reaction, the mass ratio of the mono-di-mixed methylamine to the γ-butyrolactone raw material is controlled at (0.447-0.481):1; Preferably, the reaction temperature of the N-methylpyrrolidone synthesis reaction is controlled at 340-360° C., and the residence time is controlled at 0.5-2 h.

9. The industrial chain production process according to any one of claims 1 to 3, characterized in that: The demethylamine is carried out in a demethylamine tower, the tower top pressure is controlled at 15-20 KPaA, the tower top temperature is controlled at 58-62°C, the reflux ratio is controlled at 0.8-1.5, and the tower bottom temperature is controlled at 135-150°C; the tower top distillate is the liquid phase mixed amine, and the tower bottom liquid phase is the crude N-methylpyrrolidone.

10. The industrial chain production process according to any one of claims 1 to 3, characterized in that: The N-methylpyrrolidone is purified by using an NMP product tower, the tower top pressure is controlled at 4-6 KPaA, the tower top temperature is controlled at 95-105° C., the reflux ratio is controlled at 1.5-3.0, and the tower bottom temperature is controlled at 110-130° C.; the tower top distillate is the N-methylpyrrolidone product, and the tower bottom liquid phase is the liquid phase heavy component.

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