Low-energy-consumption tetramethyl ammonium bicarbonate preparation device

Abstract

The utility model provides a tetramethyl ammonium bicarbonate preparation device with low energy consumption, which comprises a reactive distillation tower, a static mixer, a methanol removal tower and a methanol recovery tower, a gas phase discharge port of the methanol removal tower is connected with an inlet of a steam compressor, a first branch connected with an outlet of the steam compressor is connected with a gas inlet of the methanol recovery tower, and a second branch connected with an outlet of the steam compressor is connected with a gas outlet of the methanol recovery tower. A second branch connected with an outlet of the steam compressor is connected with the first return tank through a heating medium channel of the steam generator; a third branch connected with an outlet of the first reflux tank is connected with a feed port of the methanol recovery tower, and a fourth branch connected with the outlet of the first reflux tank is connected with a tower kettle of the methanol removal tower; after pure water exchanges heat through a refrigerant channel of the steam generator, steam is output, and the steam is input into a tower kettle of the methanol removal tower through a pipeline; and the methanol recovery tower is provided with a side extraction opening for extracting high-purity methanol. The device disclosed by the utility model is low in operation energy consumption, low in equipment investment and high in raw material utilization rate, and can be used for continuously preparing high-purity TMAB and recovering to obtain a high-purity methanol product.

Description

TECHNICAL FIELD

[0001] The utility model relates to the field of chemical synthesis technology, specifically relates to a low energy consumption tetramethylammonium hydrogen carbonate preparation device. BACKGROUND

[0002] Tetramethylammonium hydroxide (TMAH), chemical formula C4H 13 NO, is an important organic strong base, can be used as electronic industry field developer and etchant and integrated circuit chemical mechanical polishing process ultra-pure cleaning agent. TMAH is extremely high in purity requirement in the application process, and the early silver oxide method and electrolysis tetramethylamonnium chloride preparation tetramethylammonium hydroxide have many impurity ions, high cost, strong corrosion to equipment and other defects, and toxic gas chlorine is produced in the process of electrolysis tetramethylammonium chloride. In recent years, the process for preparing tetramethylammonium hydroxide from tetramethylammonium bicarbonate (TMAB) as raw material has been widely used, and TMAB aqueous solution is obtained by ion membrane electrolysis method, which can effectively reduce the impurity ion content, reduce the corrosion of equipment, and avoid the emission of chlorine as a toxic and harmful gas.

[0003] And the raw material TMAB can be synthesized by two-step reaction: (1) quaternary amination reaction, trimethylamine and dimethyl carbonate are used as raw materials to prepare methyl carbonate tetramethylammonium by quaternary ammonium reaction in solvent methanol; (2) hydrolysis reaction, methyl carbonate tetramethylammonium is hydrolyzed to generate TMAB when water is encountered, and the specific chemical reaction equation is as follows:

[0004] (CH3)3N+(CH3O)2CO→(CH3)4NOCOOCH3,

[0005] (CH3)4NOCOOCH3+H2O→(CH3)4NOCOOH+CH3OH.

[0006] In the process of preparing TMAB, methanol is the solvent of the reaction system and also the byproduct of the synthesis reaction; In the process of preparing TMAH by electrolyzing TMAB, no purification equipment for removing organic matter is set, and only the ion membrane in the electrolytic cell prevents methanol molecules from migrating to the product cathode chamber, so that the content of methanol in the raw material TMAB solution needs to be as low as possible in order to ensure that the content of methanol in TMAH product is ≤40ppm; Therefore, in order to obtain high-purity TMAB solution, methanol, unconverted trimethylamine and dimethyl carbonate need to be separated from TMAB aqueous solution, and qualified methanol byproduct needs to be prepared for external sales.

[0007] The patent CN217568669U synthesizes TMAB by adopting a two-stage reaction kettle series connection mode, utilizes the coupling separation of two-stage distillation tanks and a rectifying column to separate trimethylamine and methanol and the like in the synthesis process. However, the method has large equipment investment and high energy consumption for the series connection kettle reactor, and the actual operation proves that the trimethylamine and dimethyl carbonate and the like cannot be effectively separated from the methanol product through the distillation tank only, which will seriously affect the quality and sales of the byproduct methanol.

[0008] The patent CN107281994A proposes a device and method for synthesizing TMAB by adopting a circulating column pipe reactor and a pipe reactor in series. The method adopts a two-stage double-effect falling film evaporator to flash the TMAB, methanol, trimethylamine and the like to obtain a methanol, dimethyl carbonate and trimethylamine mixed solution for recycling to the reaction device, and simultaneously generates a methanol solution and a tetramethyl ammonium bicarbonate product. In the method, the pipe reactor is difficult to overcome the problems of uneven mixing at the initial stage of the reaction, difficulty in timely removal of reaction heat and the like, and a large amount of methanol aqueous solution is generated in the evaporation process, which is difficult to completely recycle in the reaction system and needs to be further treated in depth, and the overall process has high energy consumption.

[0009] The patent CN208407002U proposes a tower type reaction structure for synthesizing dimethyl carbonate. The reaction tower is divided into upper and lower parts. The lower part is circulated and mixed by an external pump on a circulating loop, and the reaction temperature is controlled by an external condenser to improve the mass transfer and heat transfer effects. Meanwhile, the circulating speed of the pump is controlled to ensure that the upper part of the reaction tower adopts a plug flow mode from bottom to top, so that the reaction is fully reacted and discharged at the top of the tower. However, the method does not propose a method for preliminarily separating methanol, trimethylamine and dimethyl carbonate during the quaternary ammonium reaction.

[0010] The patent CN221267175U proposes a new separation and purification equipment for methanol, trimethylamine and dimethyl carbonate. A side line methanol product outlet is arranged in the upper part of the methanol separation tower, and the extracted methanol product does not contain trimethylamine impurities, which greatly improves the quality of the methanol product. However, the energy utilization rate of the overall process is relatively low.

[0011] In summary, the existing preparation process of tetramethyl ammonium bicarbonate has technical problems such as large equipment investment, high energy consumption and low product purity. Practical new type content

[0012] In view of the deficiencies in the prior art, the practical new type discloses a low-energy-consumption tetramethyl ammonium bicarbonate preparation device. The device has low operation energy consumption, low equipment investment, high raw material utilization rate, can continuously prepare high-purity TMAB, and can recover high-purity methanol products.

[0013] In order to realize the above technical purpose, the utility model provides a kind of low-energy consumption tetramethylammonium hydrogen carbonate preparation device, which comprises reaction rectifying tower, static mixer, methanol removal tower and methanol recovery tower, wherein:

[0014] The feed inlet of the reaction rectifying tower is connected to the dimethyl carbonate input pipe, the trimethylamine input pipe and the solvent methanol input pipe, and the liquid phase outlet of the reaction rectifying tower is connected to the first feed inlet of the static mixer.

[0015] The second feed inlet of the static mixer is connected to the hot water input pipe, and the outlet is connected to the feed inlet of the methanol removal tower.

[0016] The gas phase outlet of the methanol removal tower is connected to the inlet of the steam compressor, the first branch connected to the outlet of the steam compressor is connected to the gas inlet of the methanol recovery tower, the second branch connected to the outlet of the steam compressor is connected to the first reflux tank through the heat medium channel of the steam generator, the third branch connected to the outlet of the first reflux tank is connected to the feed inlet of the methanol recovery tower, and the fourth branch connected to the outlet of the first reflux tank is connected to the tower kettle of the methanol removal tower.

[0017] The methanol recovery tower is provided with a side outlet for extracting high-purity methanol.

[0018] The process flow for preparing tetramethylammonium hydrogen carbonate using the above low-energy consumption tetramethylammonium hydrogen carbonate preparation device includes:

[0019] Step (1), trimethylamine, dimethyl carbonate and solvent methanol are input into the reaction rectifying tower, and quaternary amination reaction occurs in the reaction rectifying tower to generate methyl carbonate tetramethylammonium, obtaining a first gas phase and a first liquid phase.

[0020] Step (2), the first liquid phase is hydrolyzed with steam to generate tetramethylammonium hydrogen carbonate, obtaining a material to be separated.

[0021] The reaction rectifying tower is used for continuous quaternary ammonium reaction, and the preliminary separation of unreacted raw materials and solvent in the tower is realized at the same time as the heat release of quaternary amination reaction, the overall equipment occupies small area, and the equipment investment is low, which not only overcomes the shortcomings of high equipment cost and large area of traditional multi-kettle series reactor, but also avoids the disadvantages of high reaction pressure and difficult heat removal of tubular reactor.

[0022] Step (3), the material to be separated is input into a methanol removal column for rectification, to obtain a second gas phase and a second liquid phase, the second liquid phase being a tetramethylammonium bicarbonate aqueous solution; the second gas phase is divided into two parts after being heated and pressurized: one part is input into a methanol recovery column as a heat source; the other part is used as a heat source to generate steam through heat exchange with water, and the part of the steam is input into the column bottom of the methanol removal column, the second gas phase after heat exchange and condensation obtains a second liquid phase material, part of the second liquid phase material is returned to the methanol removal column as reflux, and the other part is input into the methanol recovery column as feed.

[0023] In the above technical solution, the heat pump technology is used to heat and pressurize the second gas phase collected from the column top of the methanol removal column, to improve the steam grade of the column top, and part of the second gas phase after being heated and pressurized is used to generate steam, so that the generated steam is input into the methanol removal column to provide heat energy for the column bottom of the methanol removal column, so that the column bottom of the methanol removal column does not need to be additionally input with steam, and the column top of the methanol removal column also does not need to be additionally input with cooling circulating water, thereby reducing the process energy consumption; in addition, part of the second gas phase after being heated and pressurized is directly input into the subsequent methanol recovery column as a heat source, thereby reducing the consumption of steam of the methanol recovery column reboiler and further reducing the energy consumption.

[0024] Step (4), high-purity methanol is collected from the side of the methanol recovery column.

[0025] Compared with the prior art, the present application continuously prepares and separates tetramethylammonium bicarbonate through the reaction rectification column, the static mixer, the methanol removal column and the methanol recovery column, and has high overall equipment intensification degree and low operation cost; in the product separation stage, the heat pump rectification technology is used for energy integration with the separation process of the reaction material, thereby significantly reducing the overall energy consumption of the tetramethylammonium bicarbonate preparation technology; the methanol in the TMAB aqueous solution is removed by steam stripping from the column bottom of the methanol removal column, so that the methanol content in the TMAB aqueous solution is ≤30ppm, which meets the subsequent electrolysis process requirements. BRIEF DESCRIPTION OF DRAWINGS

[0026] The drawings constituting a part of the specification of the present application are used to provide a further understanding of the present application, and the schematic embodiments of the present application and the explanations thereof are used to explain the present application, and do not constitute an improper limitation on the present application. In the drawings:

[0027] Figure 1 Fig. 1 shows a structural diagram of the low-energy-consumption tetramethylammonium bicarbonate preparation device of the present application;

[0028] In the drawings, Figure 1Includes the following reference numerals: 1-Reactive distillation column, 11-First heat exchanger, 12-Second reflux tank, 13-First reboiler, 2-Static mixer, 3-Methanol removal column, 31-Steam generator, 32-First reflux tank, 33-Steam compressor, 4-Methanol recovery column, 41-Second heat exchanger, 42-Third reflux tank, 43-Second reboiler.

[0029] Figure 2 A structural diagram of the preparation process of tetramethylammonium bicarbonate in Comparative Example 1 is shown.

[0030] in, Figure 2 Includes the following reference numerals: 51-first reaction vessel, 52-second reaction vessel, 53-third reaction vessel, 61-water heater, 62-static mixing device, 71-first-stage falling film evaporator, 72-second-stage falling film evaporator, 73-preparation tank, 8-methanol removal tower, 9-methanol recovery tower. Detailed Implementation

[0031] To facilitate understanding of this utility model, a more comprehensive description of it will be provided below, along with preferred embodiments. However, it should be understood that these embodiments are merely for more detailed explanation and should not be construed as limiting the utility model in any way, i.e., not limiting the scope of protection of this utility model.

[0032] Unless otherwise defined, the technical terms used in the following embodiments have the same meaning as commonly understood by those skilled in the art to which this invention pertains. The terms "first," "second," and "third" in this invention are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first," "second," or "third" may explicitly or implicitly include one or more of that feature.

[0033] In the description of this specification, the references to terms such as "further example," "optional example," and "example" refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. The illustrative expressions of the above terms in this specification do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0034] Example 1

[0035] A low-energy-consumption tetramethylammonium bicarbonate preparation apparatus, such as Figure 1 As shown, it includes a reactive distillation column 1, a static mixer 2, a methanol removal column 3, and a methanol recovery column 4, wherein:

[0036] The feed inlet of the reaction rectification column 1 is connected with a dimethyl carbonate input pipe, a trimethylamine input pipe and a solvent methanol input pipe, and the liquid phase outlet of the reaction rectification column 1 is connected with the first feed inlet of the static mixer 2;

[0037] The second feed inlet of the static mixer 2 is connected with a hot water input pipe, and the outlet of the static mixer 2 is connected with the feed inlet of the methanol removal column 3;

[0038] The gas phase outlet of the methanol removal column 3 is connected with the inlet of the steam compressor 33, the first branch connected with the outlet of the steam compressor 33 is connected with the gas inlet of the methanol recovery column 4, the second branch connected with the outlet of the steam compressor 33 is connected with the heat medium channel of the steam generator 31 and the first reflux tank 32, the third branch connected with the outlet of the first reflux tank 32 is connected with the feed inlet of the methanol recovery column 4, the fourth branch connected with the outlet of the first reflux tank 32 is connected with the column still of the methanol removal column 3, and the steam generated by the heat exchange of the pure water through the cold medium channel of the steam generator 31 is output to the column still of the methanol removal column 3 through a pipeline;

[0039] The methanol recovery column 4 is provided with a side outlet for collecting high-purity methanol.

[0040] In the above device, the heat pump technology is used in the methanol removal column 3, the gas phase material collected from the top of the methanol removal column 3 is heated and pressurized by the steam compressor 33 to improve the quality of the steam, part of the steam is directly input to the subsequent methanol recovery column 4 as a heat source, and the other part of the steam is heated by the steam generator 31 to obtain steam, and the steam is directly input to the column still of the methanol removal column 3, and is used for stripping of trace methanol in the column still of the methanol removal column 3. By coupling the heat pump rectification device, the methanol removal column 3 does not need to input additional heat source or circulating cooling water during operation, which significantly reduces the energy consumption; in addition, part of the steam after heating and pressurizing is used as a heat source of the methanol recovery column 4, which further reduces the energy consumption of the device.

[0041] In an optional example of the embodiment, the column still of the reaction rectification column 1 is provided with a first reboiler 13 for providing a heat source, and the methanol recovery column 4 is provided with a second reboiler 43 for providing a heat source, and the reboiler cooperates with part of the steam after heating and pressurizing to provide a heat source for the methanol recovery column 4.

[0042] It should be noted that the skilled person in the art can set equipment or components for promoting the flow of the material flow on the material flow conveying pipeline according to the needs, such as a circulating pump, etc., and this does not limit the protection scope of the utility model.

[0043] Embodiment 2

[0044] Based on the low-energy-consumption tetramethylammonium bicarbonate preparation device shown in embodiment 1, the structure of the reaction rectification column 1 is optimized in this embodiment.

[0045] Optionally, the gas phase outlet of the reaction distillation column 1 is connected to the feed inlet of the reaction distillation column 1; in the actual process, the material including part of the methanol and unreacted trimethylamine and dimethyl carbonate is taken out from the gas phase outlet of the reaction distillation column 1, and the material is returned to the feed inlet of the reaction distillation column 1 to continue the reaction, thereby improving the utilization rate of raw materials.

[0046] Further optionally, the gas phase outlet of the reaction distillation column 1 is connected to the feed inlet of the reaction distillation column 1 through the heat medium channel of the first heat exchanger 11; the pure water input pipe exchanges heat with the cold medium channel of the first heat exchanger 11 to generate steam, and is connected to the second feed inlet of the static mixer 2. Thus, the heat energy in the material taken out from the gas phase outlet of the reaction distillation column 1 can be recycled, the heat energy is used to exchange heat with the pure water to generate steam, and the steam is used for the hydrolysis reaction in the static mixer 2, thereby further improving the energy utilization rate of the device. Further optionally, the heat medium outlet of the first heat exchanger 11 is connected to the second reflux tank 12, and the outlet of the second reflux tank 12 is connected to the top and the feed inlet of the reaction distillation column 1 through pipes, respectively.

[0047] Optionally, the number of theoretical plates of the reaction distillation column 1 is 36-68; the feeding position of dimethyl carbonate is the plate 1 / 5-1 / 4 away from the top, and the feeding position of trimethylamine and methanol is the plate 1 / 5-1 / 3 away from the bottom.

[0048] Example 3

[0049] Based on the low-energy-consumption tetramethylammonium hydroxide preparation device shown in Example 1, the structure of the methanol removal column 3 is optimized in this embodiment.

[0050] Optionally, the bottom of the methanol removal column 3 is provided with a discharge outlet for taking out tetramethylammonium hydroxide solution. Actual operation shows that the methanol content in the TMAB aqueous solution taken out from the bottom of the methanol removal column 3 is ≤30 ppm, which meets the requirements of the subsequent electrolysis process to prepare high-purity TMAH.

[0051] Optionally, the number of theoretical plates of the methanol removal column 3 is 20-30, and the feeding position is the plate 1 / 4-1 / 3 away from the top.

[0052] Example 4

[0053] Based on the low-energy-consumption tetramethylammonium hydroxide preparation device shown in Example 1, the structure of the methanol recovery column is optimized in this embodiment.

[0054] Optionally, the number of theoretical plates of the methanol recovery column is 60-70; the feeding position is the plate 1 / 2-3 / 4 away from the top, the gas inlet is located at the bottom, and the side discharge port is located at the plate 1 / 5 away from the top.

[0055] Optionally, the gas phase outlet of the methanol recovery column 4 is connected to the feed inlet of the reactive distillation column 1; in the actual process, the material containing trimethylamine and dimethyl carbonate taken out from the gas phase outlet of the methanol recovery column 4 is returned to the reactive distillation column 1, so as to improve the utilization rate of raw materials.

[0056] Further optionally, the gas phase outlet of the methanol recovery column 4 is condensed by the second heat exchanger 41 to obtain condensate input into the third reflux tank 42, one branch of which is returned to the methanol recovery column 4 and the other branch is returned to the reactive distillation column 1.

[0057] Embodiment 5

[0058] Based on the low-energy-consumption tetramethylammonium bicarbonate preparation device shown in Embodiment 1, the column still of the methanol recovery column 4 is provided with a liquid phase outlet for outputting a dilute methanol solution, which is connected to the pipeline connecting the outlet of the static mixer 2. In the actual process, the concentration of TMAB in the material output from the static mixer 2 can be optionally adjusted to 35wt%-45wt%, so as to improve the efficiency of subsequent separation and recovery. In this embodiment, the dilute methanol solution output from the column still of the methanol recovery column 4 is used as a diluent to regulate the concentration of TMAB in the material output from the static mixer 2, which can improve the operability of the process and reduce the cost of the process.

[0059] Optionally, a fifth branch for inputting pure water is connected to the pipeline connecting the outlet of the static mixer 2, so that pure water and / or the dilute methanol solution output from the column still of the methanol recovery column 4 can be used as a diluent to regulate the concentration of TMAB in the material output from the static mixer 2.

[0060] Embodiment 6

[0061] Based on the low-energy-consumption tetramethylammonium bicarbonate preparation device shown in Embodiment 1, this embodiment shows a tetramethylammonium bicarbonate preparation process under specific working conditions. It should be noted that this embodiment is only a better display and does not limit the scope of protection of the present application.

[0062] A low-energy-consumption tetramethylammonium bicarbonate preparation process, specifically comprising the following steps:

[0063] Step (1), trimethylamine, dimethyl carbonate and solvent methanol are fed into the reactive distillation column 1, and the quaternary amination reaction occurs in the reactive distillation column 1 to generate methyl carbonate tetramethyl ammonium, and a first gas phase and a first liquid phase are obtained. The reactive distillation column 1 is provided with 48 theoretical plates, and the reflux ratio is 1.5; the dimethyl carbonate is fed into the 12th theoretical plate (counted from top to bottom), the trimethylamine and the solvent methanol are fed into the 36th theoretical plate, and the dimethyl carbonate, the trimethylamine and the solvent methanol are fed in a molar ratio of 1:1.03:2, and the total feeding amount is 108.84 kg / h. The top temperature of the reactive distillation column 1 is 117.6°C, the pressure is 0.6 MPaA, the first gas phase containing unreacted dimethyl carbonate, trimethylamine and solvent methanol is collected at the top at a rate of 27.71 kg / h; the temperature of the reaction section is 117.7-132.4°C, the pressure is 0.6 MPaA, the dimethyl carbonate and the trimethylamine are countercurrently contacted in the reaction section; the temperature of the column bottom is 169.6°C, the pressure is 0.6 MPaA, and the first liquid phase is collected at the column bottom at a rate of 81.13 kg / h; the first liquid phase is a mixture containing methyl carbonate tetramethyl ammonium, and the yield of methyl carbonate tetramethyl ammonium is 97.7%.

[0064] Step (2), the methyl carbonate tetramethyl ammonium and hot water are mixed in the static mixer 2 to generate the separation material containing TMAB and methanol, and the operation conditions of the static mixer 2 are 120°C and normal pressure. In this step, the dilute methanol solution and / or pure water collected from the column bottom of the subsequent methanol recovery column 4 are used as dilution liquid to adjust the concentration of TMAB in the separation material.

[0065] Step (3), the feedstock was introduced into the methanol removal column 3 at a rate of 108.10 kg / h for rectification, the methanol removal column 3 was provided with 24 theoretical plates, and the feed inlet was located at the 9th theoretical plate; the operating conditions at the top of the methanol removal column 3 were 69.8°C and 0.04 MPaA. The top of the methanol removal column 3 was connected with a steam compressor 33 via a pipeline, and the heat pump technology was used to increase the temperature and pressure of the steam to 195.6°C and 0.12 MPaA to obtain the second gas phase after temperature and pressure increase. Part of the second gas phase after temperature and pressure increase was introduced into the subsequent methanol recovery column 4 as a heat source for methanol recovery rectification, and the other part was circulated into the heat medium channel of the steam generator 31 as a heat source. Pure water was heated and evaporated in the coolant channel of the steam generator 31 to obtain steam, and this part of the steam was introduced into the column kettle of the methanol removal column 3 as a heat source and used for stripping of methanol in the column kettle liquid. The condensation temperature of the condensed material was 83.7°C, part of the second liquid phase was refluxed to the top of the methanol removal column 3 to maintain a reflux ratio of 0.3, and the other part of the second liquid phase was transported into the subsequent methanol recovery column 4 for further refining and recovery of methanol. The temperature at the kettle of the methanol removal column 3 was 82.8°C, and the pressure was 0.04 MPaA. The column kettle was taken out at a rate of 111.48 kg / h, and the 60wt% TMAB aqueous solution (the methanol content was 15 ppm) was obtained.

[0066] Step (4), the methanol recovery column 4 was provided with 60 theoretical plates, the reflux ratio was 14, the gas phase feed inlet was located at the 59th theoretical plate, and the liquid phase feed inlet was located at the 40th theoretical plate; the temperature at the top of the recovery column was 64.4°C, the pressure was 0.103 MPaA, the third gas phase containing trimethylamine, dimethyl carbonate and methanol was taken out from the top at a rate of 6.24 kg / h, and was returned to the reaction rectification column 1 after condensation for reuse; the methanol product outlet of the methanol recovery column 4 was located at the 12th theoretical plate, and the methanol product with a mass fraction of 99.5wt% was taken out at a rate of 17.11 kg / h. The temperature at the kettle of the methanol recovery column 4 was 96.5°C, the pressure was 0.103 MPaA, and the dilute methanol aqueous solution with a methanol mass fraction of 0.05wt% was taken out from the kettle at a rate of 32.47 kg / h. This part of the dilute methanol solution was mixed with the feedstock as a diluent to adjust the TMAB concentration of the feedstock.

[0067] Comparative Example 1

[0068] Comparative Example 1 used Figure 2The shown device carries out tetramethylammonium bicarbonate preparation, and in the process: dimethyl carbonate, trimethylamine and solvent methanol are input into the first reaction kettle 51 and pass through the second reaction kettle 52 and the third reaction kettle 53 in series to carry out quaternary ammonium reaction, the reacted material is input into the first-stage falling film evaporator 71 to carry out gas-liquid separation, the obtained gas-phase material is returned to the first reaction kettle 51, and the liquid-phase material carries out hydrolysis reaction with pure water heated by the water heater 61 in the static mixing device 62; the material after the hydrolysis reaction is input into the second-stage falling film evaporator 72 to carry out gas-liquid separation, the obtained gas-phase material is input into the recovered methanol tower 9, and the liquid-phase material is input into the preparation tank 73 and is input into the methanol removal tower 8 after being diluted with pure water; the TMAB solution is taken out from the tower kettle of the methanol removal tower 8, the overhead material is condensed, part of which is returned and part of which is input into the recovered methanol tower 9; the methanol product is taken out from the side of the recovered methanol tower 9, the overhead material is returned to the first reaction kettle 51, and the tower kettle material is used to input into the preparation tank 73.

[0069] The specific process includes the following steps:

[0070] Step (1), in the three-stage series reaction kettle, the molar ratio of dimethyl carbonate, trimethylamine and solvent methanol is 1:1.03:2, and the feeding rate is 108.84 kg / h; the control conditions of the reaction kettle are 110-130℃, 0.6 MPaA, and the yield of methyl carbonate tetramethylammonium after reaction is 97.4%; the methyl carbonate tetramethylammonium mixed solution generated in the reaction is input into the first-stage falling film evaporator 71, and after evaporation, dimethyl carbonate, trimethylamine and solvent methanol are taken out and directly reused; the operating conditions of the first-stage falling film evaporator 71 are 0.11 MPaA and 105℃; the remaining methyl carbonate tetramethylammonium is mixed with hot water and hydrolyzed and then input into the second-stage falling film evaporator 72, 0.35 MPaA saturated steam is input under 0.11 MPaA pressure to maintain the temperature of the TMAB mixed solution at 120℃; the gas-phase sampling rate of the second-stage falling film evaporator 72 is 28.73 kg / h, part of which is condensed and used as a reaction solvent in the synthesis section, and the rest is directly sent to the recovered methanol tower 9 as a heat source; the liquid-phase sampling material of the second-stage falling film evaporator 72 is sent to the preparation tank 73, pure water and the recovered methanol tower 9 tower kettle taken-out solution are input, the TMAB concentration is adjusted to 40%, and then it is transported to the methanol removal tower 8, and the transportation flow rate is 166.92 kg / h.

[0071] Step (2), the methanol removal column 8 is provided with 24 theoretical tray numbers, and the feeding position is the 9th theoretical tray; the top operating condition is 71.5 DEG C, 0.04 MPaA, the top vapor output is 72.33 kg / h, the vapor pipeline is directly connected with the condenser, part of the condensed liquid is returned to the top of the methanol removal column 8, the reflux ratio of the methanol removal column 8 is maintained at 0.3, and the remaining condensed liquid is transported into the recovered methanol column 9 to be further refined and recovered; the column bottom operating condition of the methanol removal column 8 is 79.8 DEG C, 0.04 MPaA, and the column bottom is taken out at a rate of 111.22 kg / h to output 60wt% TMAB aqueous solution (the methanol content is 68ppm).

[0072] Step (3), the recovered methanol column 9 is provided with 60 theoretical tray numbers, the reflux ratio is 35, the gas phase feeding port is located at the 59th theoretical tray, and the liquid phase feeding port is located at the 40th theoretical tray. The top operating condition of the recovered methanol column 9 is 65.8 DEG C, 0.103 MPaA, the top is taken out to output a mixed liquid of trimethylamine, dimethyl carbonate and methanol, and the output rate is 0.32 kg / h; after being condensed, the mixed liquid is returned to the synthesis system to be reused; the methanol product outlet of the recovered methanol column 9 is located at the 12th theoretical tray, and the mass fraction of 99.5wt% methanol product is taken out at a rate of 15.50 kg / h; the column bottom operating condition of the recovered methanol column 9 is 96.5 DEG C, 0.103 MPaA, and the column bottom is taken out at a rate of 35.15 kg / h to output a dilute methanol aqueous solution with a methanol mass fraction of 0.05wt%, and the dilute methanol aqueous solution is input into the preparation tank 73.

[0073] Further, the energy consumption of each stage and the overall energy consumption of the embodiment 4 and the comparative example 1 are compared, and the results are shown in Table 1.

[0074] Table 1

[0075]

[0076]

[0077] It can be verified from Table 1 that, compared with the comparative example 1, the comprehensive energy consumption of the reaction and hydrolysis device of the embodiment 4 is reduced by 21.34% in the quaternary ammonium reaction and hydrolysis reaction stage (the comparative example 1 also includes the preliminary separation of the secondary falling film device membrane evaporator); in the methanol removal stage, the comprehensive energy consumption of the methanol removal column 3 of the embodiment 4 is reduced by 93.13% compared with the comparative example 1; in the methanol recovery stage, the comprehensive energy consumption of the methanol recovery column 4 of the embodiment 4 is reduced by 72.58% compared with the comparative example 1. In summary, the comprehensive energy consumption of the embodiment 4 is reduced by 65.73% compared with the comparative example 1, which reflects a significant energy saving and consumption reduction advantage.

[0078] It should be noted that the above is a further detailed description of the present application in conjunction with specific embodiments, and cannot be considered as limiting the specific implementation of the present application to these descriptions. For ordinary skilled persons in the technical field to which the present application belongs, without departing from the concept of the present application, a number of simple improvements can be made, and all should be considered as belonging to the scope of protection of the present application.

Claims

1. A low-energy-consumption tetramethylammonium bicarbonate preparation apparatus, characterized in that, It includes a reactive distillation column (1), a static mixer (2), a methanol removal column (3), and a methanol recovery column (4), wherein: The feed inlet of the reactive distillation column (1) is connected to the dimethyl carbonate input pipe, the trimethylamine and the solvent methanol input pipe, and the liquid phase outlet of the reactive distillation column (1) is connected to the first feed inlet of the static mixer (2). The second inlet of the static mixer (2) is connected to the hot water input pipe, and its outlet is connected to the inlet of the methanol removal tower (3); The vapor outlet of the methanol removal tower (3) is connected to the inlet of the steam compressor (33). The first branch connected to the outlet of the steam compressor (33) is connected to the inlet of the methanol recovery tower (4). The second branch connected to the outlet of the steam compressor (33) is connected to the first reflux tank (32) via the heat medium channel of the steam generator (31). The third branch connected to the outlet of the first reflux tank (32) is connected to the inlet of the methanol recovery tower (4). The fourth branch connected to the outlet of the first reflux tank (32) is connected to the bottom of the methanol removal tower (3). Pure water is output as steam after heat exchange through the refrigerant channel of the steam generator (31). The steam is then input into the bottom of the methanol removal tower (3) via a pipeline. The methanol recovery tower (4) is equipped with a side sampling port for extracting high-purity methanol.

2. The low-energy-consumption tetramethylammonium bicarbonate preparation apparatus according to claim 1, characterized in that, The vapor outlet of the reactive distillation column (1) is connected to the feed inlet of the reactive distillation column (1).

3. The low-energy-consumption tetramethylammonium bicarbonate preparation apparatus according to claim 2, characterized in that, The gas outlet of the reactive distillation column (1) is connected to the feed inlet of the reactive distillation column (1) after passing through the heat medium channel of the first heat exchanger (11); the pure water input pipe generates steam through heat exchange in the cold medium channel of the first heat exchanger (11) and is connected to the second feed inlet of the static mixer (2).

4. The low-energy-consumption tetramethylammonium bicarbonate preparation apparatus according to claim 1, characterized in that, The theoretical number of plates in the reactive distillation column (1) is 36 to 68; the feed position of the dimethyl carbonate is 1 / 5 to 1 / 4 of the distance from the top of the column, and the feed positions of the trimethylamine and methanol are 1 / 5 to 1 / 3 of the distance from the bottom of the column.

5. The low-energy-consumption tetramethylammonium bicarbonate preparation apparatus according to claim 1, characterized in that, The bottom of the methanol removal tower (3) is provided with an outlet for collecting the tetramethylammonium bicarbonate aqueous solution.

6. The low-energy-consumption tetramethylammonium bicarbonate preparation apparatus according to claim 1, characterized in that, The methanol removal tower (3) has a theoretical number of 20 to 30 plates, and the feed position is 1 / 4 to 1 / 3 of the distance from the top of the tower.

7. The low-energy-consumption tetramethylammonium bicarbonate preparation apparatus according to claim 1, characterized in that, The methanol recovery tower (4) has a theoretical number of 60 to 70 plates; its feed inlet is located on a plate 1 / 2 to 3 / 4 of the distance from the top of the tower, its gas inlet is located at the bottom of the tower, and its side outlet is located on a plate 1 / 5 of the distance from the top of the tower.

8. The low-energy-consumption tetramethylammonium bicarbonate preparation apparatus according to claim 1, characterized in that, The vapor outlet of the methanol recovery tower (4) is connected to the feed inlet of the reactive distillation tower (1).

9. The low-energy-consumption tetramethylammonium bicarbonate preparation apparatus according to claim 1, characterized in that, The methanol recovery tower (4) is equipped with a liquid phase outlet for discharging a dilute methanol solution, which is connected to a pipeline that connects to the outlet of the static mixer (2).

10. The low-energy-consumption tetramethylammonium bicarbonate preparation apparatus according to any one of claims 1-9, characterized in that, The fifth branch for inputting pure water is connected to the pipeline that connects to the outlet of the static mixer (2).

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