A device for the concentrated preparation of sodium methoxide

Abstract

The utility model belongs to a kind of device for preparing sodium methoxide, including sodium hydroxide supply part and methanol supply part, sodium hydroxide supply part and methanol supply part are connected with sodium hydroxide methanol solution configuration part respectively, the outlet of sodium hydroxide methanol solution configuration part is connected with the import of reaction rectifying column, reaction rectifying column bottom liquid phase outlet is connected with three-way, the second end of three-way is connected with the circulating import of reaction rectifying column by external reboiler, the third end of three-way is connected with product tank;Sodium hydroxide methanol solution configuration part includes premixing kettle for receiving sodium hydroxide in sodium hydroxide supply part and methanol in methanol supply part, the import of outlet of premixing kettle is connected with alkali tank, the outlet of alkali tank is connected with the import of reaction rectifying column by precipitation tank;With the advantages of reasonable process design, equipment operation safety is good, reaction rectifying column continuous production can be realized and energy consumption is low.

Description

Technical Field

[0001] This invention belongs to the field of sodium methoxide technology, specifically an apparatus for the concentration and preparation of sodium methoxide. Background Technology

[0002] Sodium methoxide is a hazardous chemical that reacts readily with water to produce sodium hydroxide and methanol. It is highly hygroscopic, strongly alkaline, corrosive, and spontaneously combustible. It is mainly used in the pharmaceutical industry, as a condensing agent in organic synthesis, a chemical reagent, and a catalyst in the treatment of edible oils. Industrially, it typically exists in two forms: solid sodium methoxide and a methanol solution of sodium methoxide. Industrial production of sodium methoxide primarily involves the reaction of metallic sodium with methanol, producing sodium methoxide as a byproduct. The process, including the collection and emission of hydrogen, presents significant safety risks. Therefore, developing a safe sodium methoxide production process has become a pressing technical challenge. Utility Model Content

[0003] To overcome the above deficiencies, this utility model provides an apparatus for concentrating and preparing sodium methoxide, thereby solving the technical problems existing in the prior art.

[0004] The technical solution adopted by this utility model to solve its technical problem is: An apparatus for concentrating and preparing sodium methoxide includes a sodium hydroxide supply unit and a methanol supply unit. The sodium hydroxide supply unit and the methanol supply unit are respectively connected to a sodium hydroxide-methanol solution preparation unit. The outlet of the sodium hydroxide-methanol solution preparation unit is connected to the inlet of a reactive distillation column. The liquid phase outlet at the bottom of the reactive distillation column is connected to a three-way valve. The second end of the three-way valve is connected to the circulation inlet of the reactive distillation column via an external reboiler, and the third end of the three-way valve is connected to a product tank. The sodium hydroxide-methanol solution preparation unit includes a premixing vessel for receiving sodium hydroxide from the sodium hydroxide supply unit and methanol from the methanol supply unit. The outlet of the premixing vessel is connected to the inlet of a dissolving alkali tank, and the outlet of the dissolving alkali tank is connected to the inlet of the reactive distillation column via a precipitation tank.

[0005] The beneficial effects of this invention are as follows: In traditional processes, sodium metal reacts with methanol, and the reactive form of sodium metal replaces hydrogen atoms in methanol, resulting in the generation of a hydrogen hazard during sodium methoxide production. This invention employs a sodium hydroxide supply section and a methanol supply section to supply sodium hydroxide and methanol. Utilizing the double displacement reaction mechanism, hydroxide ions constrain excess hydrogen atoms in methanol. In subsequent processes, a reactive distillation column is used to remove light hydrogen atoms, separating methanol and water from sodium methoxide to obtain sodium methoxide. Furthermore, this invention uses a premixing vessel to premix sodium hydroxide and methanol before introducing them into a dissolving tank, ensuring complete dissolution of sodium hydroxide and methanol. This reduces the flow of water to subsequent processes, avoiding the difficulty in separating methanol and water from sodium methoxide in later stages.

[0006] Preferably, the outlet of the alkali dissolving tank is connected to several sedimentation tanks arranged in parallel, and the outlets of the several sedimentation tanks arranged in parallel are respectively connected to the inlet of the reactive distillation column.

[0007] Preferably, the outlet of the alkali dissolving tank is connected to several inlet branch pipes with first valves via a first delivery pump, the several inlet branch pipes are connected to the inlets of corresponding sedimentation tanks, the outlets of several sedimentation tanks are connected to corresponding loop branch pipes with second valves, and the several loop branch pipes are connected to the inlets of the reactive distillation column via a second delivery pump.

[0008] Preferably, the bottom of the sedimentation tank is provided with a circulation pipe with a third valve, and the circulation pipe is connected to the circulation inlet of the alkali dissolving tank.

[0009] Preferably, the sodium hydroxide supply unit includes a sodium hydroxide storage area, which is connected to a packing unpacking machine via a conveyor belt, and the sodium hydroxide outlet of the packing unpacking machine is connected to a premixing kettle via a buffer funnel.

[0010] Preferably, the methanol supply unit includes a methanol storage tank, the outlet of which is connected to a premixing vessel via a methanol pump, and the inlet of which is connected to a methanol recycling unit. The methanol recycling unit includes an alcohol washing tower connected to the vapor phase outlet at the top of a reactive distillation column. The upper side of the alcohol washing tower is connected to a fresh methanol storage tank, the liquid phase outlet at the bottom of the alcohol washing tower is connected to the inlet of the methanol storage tank, and the vapor phase outlet of the alcohol washing tower is connected to a methanol sales storage tank via a condenser.

[0011] Preferably, the fresh methanol storage tank is connected to the reflux port of the reactive distillation column.

[0012] Preferably, the third end of the tee is connected to the product tank through the first channel of the first heat exchanger and the first channel of the second heat exchanger; the inlet of the second channel of the first heat exchanger is connected to the outlet of the sedimentation tank, and the outlet of the second channel of the first heat exchanger is connected to the inlet of the reactive distillation column; the inlet of the second channel of the second heat exchanger is connected to the circulating water inlet pipe, and the outlet of the second channel of the second heat exchanger is connected to the circulating water return pipe.

[0013] An apparatus for concentrating and preparing sodium methoxide according to the above scheme is constructed by supplying sodium hydroxide and methanol through a sodium hydroxide supply section and a methanol supply section. Utilizing the double decomposition reaction mechanism, hydroxide ions constrain excess hydrogen atoms in methanol. In subsequent processes, a reactive distillation column is used to remove light hydrogen atoms, separating methanol and water from sodium methoxide to obtain sodium methoxide. Furthermore, this invention employs a premixing vessel to premix sodium hydroxide and methanol, which then enters a dissolving tank to ensure complete dissolution of sodium hydroxide and methanol. This reduces the flow of water to subsequent stages, avoiding difficulties in separating methanol and water from sodium methoxide. This invention also employs several parallel-connected precipitation tanks and dissolving tanks... The outlet of the alkali tank is connected, enabling the continuous supply of raw materials to the reactive distillation column while allowing the sodium hydroxide methanol solution to settle, thus achieving continuous production of the system. Simultaneously, a circulation pipeline is installed to fully utilize the raw materials and further allow the generated salt precipitate to adsorb water in the alkali tank, reducing water flow to subsequent stages and simplifying the separation of methanol and water. In this invention, a large amount of methanol solvent evaporates in the reactive distillation column, carrying intermediates and overflowing, resulting in material waste. By setting up an alcohol washing tower and using fresh methanol to wash the methanol, the washed steam can be cooled and refluxed for sale. The methanol collected from the bottom of the alcohol washing tower can be recycled within the system. Compared to the traditional two-step process of filtration and alkali removal tower and methanol distillation tower, the above process is simpler, reduces raw material consumption during production, and achieves zero waste gas emissions. At the same time, heat exchange between the bottom liquid of the reactive distillation tower and the feed of the reactive distillation tower can pre-cool the raw materials entering the reactive distillation tower, thereby saving energy. It has the advantages of reasonable process design, good equipment operation safety, continuous production of the reactive distillation tower, and low energy consumption. Attached Figure Description

[0014] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0015] Figure 1 This is a schematic diagram of the structure of this utility model.

[0016] Figure 2 This is a schematic diagram showing the connection relationship of several sedimentation tanks in this utility model.

[0017] In the diagram: 1. Reactive distillation column; 2. External reboiler; 3. Product tank; 4. Premixing vessel; 5. Alkali dissolving tank; 6. Sedimentation tank; 7. First transfer pump; 8. First valve; 9. Second valve; 10. Second transfer pump; 11. Third valve; 12. Sodium hydroxide storage area; 13. Conveyor belt; 14. Unpacking machine; 15. Methanol storage tank; 16. Methanol washing tower; 17. Fresh methanol storage tank; 18. Condenser; 19. Methanol for sale storage tank; 20. Tee; 21. First heat exchanger; 22. Second heat exchanger; 23. Circulating water inlet pipe; 24. Circulating water return pipe; 25. Buffer funnel; 26. Methanol pump. Detailed Implementation

[0018] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present utility model.

[0019] The following is in conjunction with the appendix Figure 1 This application provides a further detailed description of an apparatus for concentrating and preparing sodium methoxide. The apparatus includes a sodium hydroxide supply unit and a methanol supply unit, both connected to a sodium hydroxide-methanol solution preparation unit. The outlet of the sodium hydroxide-methanol solution preparation unit is connected to the inlet of a reactive distillation column 1. The bottom liquid phase outlet of the reactive distillation column 1 is connected to a three-way valve 20. The second end of the three-way valve 20 is connected to the circulation inlet of the reactive distillation column via an external reboiler 2, and the third end of the three-way valve 20 is connected to a product tank 3. The sodium hydroxide-methanol solution preparation unit includes a premixing vessel 4 for receiving sodium hydroxide from the sodium hydroxide supply unit and methanol from the methanol supply unit. The outlet of the premixing vessel 4 is connected to the inlet of a dissolving alkali tank 5, and the outlet of the dissolving alkali tank 5 is connected to the inlet of the reactive distillation column 1 via a sedimentation tank 6. This invention is applicable to the concentrated preparation of sodium methoxide. Specifically, sodium hydroxide is supplied through a sodium hydroxide supply unit, and methanol is supplied as raw material through a methanol supply unit. The sodium hydroxide and methanol are then mixed in a sodium hydroxide-methanol solution preparation unit to form a sodium hydroxide-methanol solution. This sodium hydroxide-methanol solution enters a reactive distillation column 1 for distillation. In the above process, the double decomposition reaction mechanism is utilized to constrain the excess hydrogen atoms in methanol with hydroxide ions, thereby achieving the characteristics of safe production. Furthermore, a premixing tank 4 is used to premix sodium hydroxide and methanol. After premixing, the mixture enters a dissolving tank 5 to fully dissolve sodium hydroxide and methanol, thereby reducing the flow of water to subsequent processes and avoiding the defect of difficulty in separating methanol and water from sodium methoxide in the later stages.

[0020] Furthermore, such as Figure 1 ,2 As shown, the outlet of the alkali dissolving tank 5 is connected to several parallel sedimentation tanks 6, and the outlets of the several parallel sedimentation tanks 6 are respectively connected to the inlet of the reactive distillation column 1. In this invention, the premixing kettle 4 and the alkali dissolving tank 5 supply raw materials to the sedimentation tanks 6 in an intermittent manner to achieve full mixing of the materials. By setting several parallel sedimentation tanks 6, the sedimentation tanks 6 can continuously supply materials to the reactive distillation column 1, thereby ensuring the continuous operation of the reactive distillation column 1.

[0021] Furthermore, such as Figure 1 , 2 As shown, the outlet of the alkali dissolving tank 5 is connected to several inlet branch pipes equipped with first valves 8 via a first transfer pump 7. These inlet branch pipes are connected to the inlets of corresponding sedimentation tanks 6. The outlets of the sedimentation tanks 6 are connected to corresponding loop branch pipes equipped with second valves 9. These loop branch pipes are connected to the inlets of the reactive distillation column 1 via second transfer pumps 10. This configuration enables precise control, creating conditions for the continuous operation of the reactive distillation column 1.

[0022] Furthermore, such as Figure 1 , 2 As shown, the bottom of the sedimentation tank 6 is equipped with a circulation pipe with a third valve 11, which is connected to the circulation inlet of the alkali dissolving tank 5. This configuration allows the precipitate generated in the sedimentation tank 6 to be promptly transferred to the alkali dissolving tank 5. This not only fully utilizes the raw materials but also allows the generated salt precipitate to adsorb moisture in the alkali dissolving tank, reducing the flow of moisture to subsequent processes and simplifying the separation of methanol and water.

[0023] Furthermore, the sodium hydroxide supply unit includes a sodium hydroxide storage area 12, which is connected to a pack unpacking machine 14 via a conveyor belt 13. The sodium hydroxide outlet of the pack unpacking machine 14 is connected to a premixing kettle 4 via a buffer funnel 25. This configuration enables a continuous supply of sodium hydroxide raw materials to the system while reducing labor intensity, ensuring continuous production in subsequent processes.

[0024] Furthermore, the methanol supply unit includes a methanol storage tank 15. The outlet of the methanol storage tank 15 is connected to the premixing vessel 4 via a methanol pump 26. The inlet of the methanol storage tank 15 is connected to the methanol recycling unit. The methanol recycling unit includes an alcohol washing tower 16 connected to the top vapor outlet of the reactive distillation tower 1. The upper side of the alcohol washing tower 16 is connected to a fresh methanol storage tank 17. The liquid outlet at the bottom of the alcohol washing tower 16 is connected to the inlet of the methanol storage tank 15. The vapor outlet of the alcohol washing tower 16 is connected to a methanol sales storage tank 19 via a condenser 18. The aforementioned fresh methanol storage tank 17 supplies fresh methanol to the methanol washing tower 16 and washes the steam within the tower. The washed steam then enters the condenser 18 for condensation and is temporarily stored in the methanol sales storage tank 19. The methanol obtained after washing in the methanol washing tower 16 has a purity of 98.0%–99.0% and can be recycled back into the methanol storage tank 15. Compared to the traditional two-step process of using a filtration and alkali removal tower and a methanol distillation tower, this process is simpler, reduces raw material consumption during production, and achieves zero waste gas emissions. It should be noted that the condenser 18 can use circulating water for heat exchange.

[0025] Furthermore, the fresh methanol storage tank 17 is connected to the reflux port of the reactive distillation column 1.

[0026] Furthermore, the third end of the three-way valve 20 is connected to the product tank 3 via the first channel of the first heat exchanger 21 and the first channel of the second heat exchanger 22; the inlet of the second channel of the first heat exchanger 21 is connected to the outlet of the sedimentation tank 6, and the outlet of the second channel of the first heat exchanger 21 is connected to the inlet of the reactive distillation column 1; the inlet of the second channel of the second heat exchanger 22 is connected to the circulating water inlet pipe 23, and the outlet of the second channel of the second heat exchanger 22 is connected to the circulating water return pipe 24. This configuration enables heat exchange between the material extracted from the reactive distillation column 1 and the raw material entering the reactive distillation column 1, thereby achieving energy savings.

[0027] The working principle of this utility model is as follows: Bagged sodium hydroxide in the sodium hydroxide storage area 12 is conveyed to the unpacking machine 14 via conveyor belt 13. The unpacking machine 14 unpacks the bagged sodium hydroxide, and the unpacked bags are sent out. The sodium hydroxide enters the buffer funnel 25 and is then conveyed to the premixing tank 4. Methanol in the methanol storage tank 15 is conveyed to the premixing tank 4 via methanol pump 26. The sodium hydroxide and methanol are mixed to form a 10-20% sodium hydroxide methanol solution. This 10-20% sodium hydroxide methanol solution enters the alkali dissolving tank 5 and is continuously stirred for 6 hours at 20-40°C. After forming a saturated methanol solution, it enters the precipitation tank 6 for precipitation. The precipitate is redissolved in the alkali dissolving tank 5 through a circulation pipe equipped with a third valve 11. The redissolved solution then enters the subsequent precipitation tank 6 for circulation. The solution in the sedimentation tank 6 is fed into the second channel of the first heat exchanger 21 by the second transfer pump 10 for heat exchange, and then enters the reactive distillation column 1 for distillation. Part of the distillate collected in the reactive distillation column 1 is returned to the reactive distillation column 1 through the external reboiler 2 (which provides a heat source for the reactive distillation column 1 and can fully heat the alkali solution to 120-130℃) and the circulation inlet of the reactive distillation column. The other part of the distillate is fed into the product tank 3 after heat exchange through the first channel of the first heat exchanger 21 (the temperature of the distillate after heat exchange through the first channel of the first heat exchanger 21 is about 64.3℃) and the first channel of the second heat exchanger 22 (the temperature of the distillate after heat exchange through the first channel of the second heat exchanger 22 is room temperature). The product in the product tank 3 is a sodium methoxide methanol solution with a concentration of 28.5-31%. The gas phase produced in the reactive distillation column 1 (composed of 94.8% methanol and 5.2% water) enters the alcohol washing column 16 and comes into countercurrent contact with fresh methanol from the fresh methanol storage tank 17. After washing, the purity of the methanol collected can reach 98.0-99.0%. In subsequent processes, it enters the methanol storage tank 15 for recycling. The washed vapor enters the condenser 18 for condensation and is then sent to the external methanol storage tank 19 for temporary storage. The above process has the characteristics of reasonable process design, good equipment operation safety, continuous production of reactive distillation column and low energy consumption.

[0028] Experimental example: 40 tons of caustic soda flakes (99.9% purity) and 450 tons of methanol (99.9% purity) are fed into the premixing reactor 4 in batches daily for dissolving the caustic soda flakes. Simultaneously, another 450 tons of fresh methanol vapor is slowly and uniformly fed into the reactive distillation column 1 to promote the forward reaction of sodium methoxide. Additionally, 200 tons of fresh methanol are fed into the alcohol washing column 16 to recover alkaline gases from the methanol vapor, which are then recycled back into the premixing reactor 4 (this portion is based on the amount of fresh methanol) for a second reaction. Ultimately, 179.16 tons of sodium methoxide product (30% concentration) is obtained daily. Calculations show that the sodium hydroxide reaction yield in the entire production process is over 99.5%.

[0029] The foregoing has shown and described the basic principles, main features, and advantages of this utility model. Those skilled in the art should understand that this utility model is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of this utility model. Various changes and modifications can be made to this utility model without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed utility model.

Claims

1. An apparatus for concentrating and preparing sodium methoxide, characterized in that: The device includes a sodium hydroxide supply section and a methanol supply section. The sodium hydroxide supply section and the methanol supply section are respectively connected to the sodium hydroxide methanol solution preparation section. The outlet of the sodium hydroxide methanol solution preparation section is connected to the inlet of the reactive distillation column (1). The bottom liquid phase outlet of the reactive distillation column (1) is connected to a three-way valve (20). The second end of the three-way valve (20) is connected to the circulation inlet of the reactive distillation column through an external reboiler (2). The third end of the three-way valve (20) is connected to the product tank (3). The sodium hydroxide methanol solution preparation unit includes a premixing vessel (4) for receiving sodium hydroxide from the sodium hydroxide supply unit and methanol from the methanol supply unit. The outlet of the premixing vessel (4) is connected to the inlet of the alkali dissolving tank (5), and the outlet of the alkali dissolving tank (5) is connected to the inlet of the reactive distillation column (1) through a precipitation tank (6).

2. The apparatus for concentrating and preparing sodium methoxide according to claim 1, characterized in that: The outlet of the alkali dissolving tank (5) is connected to several parallel sedimentation tanks (6), and the outlets of the several parallel sedimentation tanks (6) are respectively connected to the inlet of the reactive distillation column (1).

3. The apparatus for concentrating and preparing sodium methoxide according to claim 2, characterized in that: The outlet of the alkali dissolving tank (5) is connected to several inlet branch pipes with first valves (8) via the first delivery pump (7). The several inlet branch pipes are connected to the inlets of the corresponding sedimentation tanks (6). The outlets of the several sedimentation tanks (6) are connected to the corresponding loop branch pipes with second valves (9). The several loop branch pipes are connected to the inlets of the reactive distillation column (1) via the second delivery pump (10).

4. An apparatus for concentrating and preparing sodium methoxide according to claim 2 or 3, characterized in that: The bottom of the sedimentation tank (6) is provided with a circulation pipe with a third valve (11), and the circulation pipe is connected to the circulation inlet of the alkali dissolving tank (5).

5. The apparatus for concentrating and preparing sodium methoxide according to claim 1, characterized in that: The sodium hydroxide supply unit includes a sodium hydroxide storage area (12), which is connected to a pack unpacking machine (14) via a conveyor belt (13). The sodium hydroxide outlet of the pack unpacking machine (14) is connected to a premixing kettle (4) via a buffer funnel (25).

6. The apparatus for concentrating and preparing sodium methoxide according to claim 1, characterized in that: The methanol supply unit includes a methanol storage tank (15), the outlet of which is connected to the premixing vessel (4) via a methanol pump (26), and the inlet of which is connected to the methanol recycling unit. The methanol recycling unit includes an alcohol washing tower (16) connected to the top vapor outlet of the reactive distillation tower (1). The upper side of the alcohol washing tower (16) is connected to the fresh methanol storage tank (17). The liquid outlet at the bottom of the alcohol washing tower (16) is connected to the inlet of the methanol storage tank (15). The vapor outlet of the alcohol washing tower (16) is connected to the external methanol storage tank (19) through a condenser (18).

7. The apparatus for concentrating and preparing sodium methoxide according to claim 6, characterized in that: The fresh methanol storage tank (17) is connected to the reflux port of the reactive distillation column (1).

8. The apparatus for concentrating and preparing sodium methoxide according to claim 2, characterized in that: The third end of the tee (20) is connected to the product tank (3) through the first channel of the first heat exchanger (21) and the first channel of the second heat exchanger (22); The inlet of the second channel of the first heat exchanger (21) is connected to the outlet of the sedimentation tank (6), and the outlet of the second channel of the first heat exchanger (21) is connected to the inlet of the reactive distillation column (1). The second channel inlet of the second heat exchanger (22) is connected to the circulating water inlet pipe (23), and the second channel outlet of the second heat exchanger (22) is connected to the circulating water return pipe (24).

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