Energy-saving methanol recovery device

Abstract

The utility model provides an energy-saving methanol recovery device which comprises a reaction tower, a rectifying tower and a recovery tower which are sequentially connected, part of refined methanol gas phase at the top of the rectifying tower is compressed and then provides heat for a tower kettle of the reaction tower, and part of refined methanol gas phase is compressed and then provides heat for a rectifying tower reboiler; a refined methanol gas phase at the top of the recovery tower provides heat for a recovery tower reboiler after being compressed, part of refined alcohol condensate condensed by the recovery tower reboiler flows back to the recovery tower, and part of the refined alcohol condensate flows back to the rectifying tower; an innovative efficient energy-saving technology is adopted, the recovery efficiency of methanol is remarkably improved, energy consumption is reduced, the overall production process is optimized, mature reaction towers, rectification towers and recovery towers are adopted in equipment, the structure is simple, and then the installation, debugging and maintenance difficulty of the equipment is low; mature equipment is not prone to faults, and stability and continuity of production are guaranteed.

Description

Technical Field

[0001] The present application relates to the technical field of methanol recovery in the field of sodium methoxide synthesis, and in particular to a methanol energy-saving recovery device. Background Art

[0002] Sodium methoxide is an important chemical product, mainly used as a synthetic intermediate raw material for medicines and pesticides. It can also be used as a catalyst and analytical reagent in the production of edible oil and biodiesel, and has a good market prospect. Currently, the main production methods of sodium methoxide in China are the alkaline method and the metallic sodium method, both of which have been achieved large-scale industrialization.

[0003] There are two main processes for the synthesis of sodium methoxide: the sodium process and the alkaline process. The sodium process uses methanol and metallic sodium as raw materials, while the alkaline process uses methanol and sodium hydroxide as raw materials. The metallic sodium process refers to the direct reaction of metallic sodium with alcohol to produce sodium methoxide and hydrogen. This process is simple. The sodium process once became the dominant process because of its simple equipment and small investment. However, since metallic sodium is flammable and explosive when it comes into contact with water, the hydrogen produced during the production process also has an explosion risk. Therefore, production accidents are frequent, the production process is extremely unsafe, and metallic sodium is expensive. The alkaline process uses sodium hydroxide to react with methanol to produce sodium methoxide. The reaction equation is: CH3OH+NaOH→CH3ONa+H2O. Because the metallic sodium process is less safe and The cost is relatively high. Therefore, the alkaline process has gradually replaced the sodium process and become the dominant process because it is easy to achieve automatic control, low cost and relatively safe. In large-scale continuous production in industry, the alkaline process is often used to produce sodium methoxide in a reaction stripping tower. The cost of the alkaline process is relatively low. However, there are some technical and economic challenges in the production of sodium methoxide by the alkaline process. The disadvantage of the traditional alkaline process is its high energy consumption. For example, the steam consumption for producing 30% liquid sodium methoxide is greater than 4 tons, and the comprehensive energy consumption for 1 ton of product is about 0.44 tons of standard coal. Although the improved alkaline process has reduced energy consumption through mechanical vapor recompression technology, there are still some problems. For example, the steam consumption for one ton of 30% liquid sodium methoxide is still greater than 2.3 tons, and the power consumption for circulating compression is relatively high.

[0004] In order to solve the above technical problems, some new technologies and devices have been developed, such as the new energy-saving three-tower production device for alkaline sodium methoxide and the dual heat pump energy-saving system for alkaline sodium methoxide, which aim to reduce energy consumption and improve production safety. The solid consumption per ton of sodium methoxide is reduced to 1 ton of steam, and the energy consumption is greatly reduced on the original basis. However, its promotion is still subject to certain restrictions in areas with high steam and electricity prices. In addition, the optimization of the sodium methoxide production process also focuses on improving yield, reducing energy consumption and reducing pollutant emissions. By optimizing reaction conditions, improving catalysts and equipment, the output and quality of sodium methoxide can be further improved.

[0005] For example, the alkalinity of sodium methoxide is stronger than that of sodium hydroxide. The generated sodium methoxide can easily regenerate methanol and sodium hydroxide when it comes into contact with water. Therefore, based on economic factors, resource utilization efficiency, environmental protection requirements, process stability and other reasons, methanol needs to be recovered.

[0006] The alkalinity of sodium methoxide is stronger than that of sodium hydroxide. The generated sodium methoxide can easily regenerate methanol and sodium hydroxide when it comes into contact with water. Therefore, based on economic factors, resource utilization efficiency, environmental protection requirements, process stability and other reasons, methanol needs to be recovered; there are several important reasons for recovering methanol in the synthesis process of sodium methoxide: 1. Economic factors: Methanol is a costly raw material. If it is not recovered, a large amount of new methanol will be required each time sodium methoxide is synthesized, which will significantly increase production costs; by recovering methanol, the cost of purchasing new methanol can be reduced and the economic benefits of production can be improved; 2. Resource utilization efficiency: Methanol is a limited resource. Recycling methanol helps to improve resource utilization efficiency and is in line with the principle of sustainable development; 3. Environmental protection requirements: A large amount of waste and unrecycled methanol discharged into the environment will cause environmental pollution. Recycling methanol can reduce the pollution pressure on the environment and reduce the environmental liability risk of the enterprise; In summary, recovering methanol is very necessary in the synthesis of sodium methoxide, which is of great significance for reducing costs, protecting the environment, improving resource utilization efficiency and ensuring process stability.

[0007] For example, in the solid sodium methoxide alkaline production device using a vacuum pump to recover methanol with application number CN201920407371.X, a technical solution is disclosed, including a sodium methoxide synthesis unit, a rake dryer, and a methanol negative pressure recovery device. In the utility model, the force exerted by the knocking rod on the second blocking block is perpendicular to the fixed rod, and the rotating shaft connected to the fixed rod is only subjected to the torque of the knocking rod, which will not cause the rotating shaft to bend. The knocking rod hits the second blocking block and then provides vibration to the fixed rod and the rotating shaft, which can remove the material adhering to the rotating shaft, and the cooling tower body The guide sieve plates staggered from top to bottom can effectively use the condensed liquid methanol to capture methanol gas, thereby promoting the condensation of methanol gas, effectively recovering the methanol gas volatilized in the rake dryer, and reducing the problem of low methanol recovery rate caused by the discharge of methanol gas that has not had time to condense. The multi-stage cooling unit can adjust the number of coolers that the top steam flows through according to different production volumes, avoiding insufficient cooling or excessive cooling of a single cooler; the multi-stage cooling unit set in this application has three coolers, and the top steam passes through three coolers. One or several of the coolers are cooled successively to a temporary storage box, and then refluxed through a pipeline to one or several of the three coolers for cyclic cooling, which can ensure the cooling process requirements. Compared with a single cooler, the multi-stage cooling unit can adjust the number of coolers through which the top steam flows according to different extraction rates, and can also adjust the number of reflux coolers, avoiding the disadvantages of insufficient or excessive cooling of a single cooler, ensuring reasonable energy consumption, and meeting the requirements for precise control of the operating conditions of the synthesis tower and the distillation tower; however, the application contains multiple components such as a sodium methoxide synthesis unit, a rake dryer, a methanol negative pressure recovery device, as well as relatively complex structures such as a knocking rod, a blocking block, a rotating shaft, a guide screen plate, and a multi-stage cooling unit, which may increase the difficulty of installation, commissioning and maintenance of the equipment; the complex equipment structure may also be more prone to failure, affecting the stability and continuity of production, and although the device mentions that the multi-stage cooling unit can be adjusted according to different extraction rates to avoid insufficient or excessive cooling, in actual operation, the coordinated work of multiple devices may consume more energy.

[0008] Therefore, it is necessary to provide a new technical solution to solve the above technical problems. Utility Model Content

[0009] The present application provides a methanol energy-saving recovery device, comprising a reaction tower, a distillation tower, and a recovery tower connected in sequence, wherein the distillation tower and the recovery tower kettle are respectively provided with a distillation tower reboiler and a recovery tower reboiler, and the reactor of the reaction tower is provided with a reaction tower reboiler; part of the refined methanol gas phase at the top of the distillation tower is compressed to provide heat for the reactor of the reaction tower, and part of the refined methanol gas phase is compressed to provide heat for the distillation tower reboiler; the refined methanol gas phase at the top of the recovery tower is compressed to provide heat for the recovery tower reboiler, and the refined alcohol condensate condensed in the recovery tower reboiler is partially refluxed to the recovery tower, and partially refluxed to the distillation tower.

[0010] As a preferred solution, the reaction tower is connected to a feed pipeline, and a reaction tower feed preheater is provided on the feed pipeline.

[0011] As a preferred solution, the top of the distillation tower is connected to the bottom of the reaction tower through a distillation tower gas phase pipeline 1, a compressor 1 is provided on the distillation tower gas phase pipeline 1, the distillation tower gas phase pipeline 1 is connected to a distillation tower gas phase pipeline 2, the distillation tower gas phase pipeline 2 is connected to a distillation tower reboiler, and a compressor 2 is provided on the distillation tower gas phase pipeline 2.

[0012] As a preferred solution, the output end of the distillation tower reboiler is connected to the upper part of the distillation tower through a distillation tower reboiler output pipeline, and a distillation tower cooler, a distillation tower reflux tank, and a reflux pump are sequentially arranged on the distillation tower reboiler output pipeline between the distillation tower reboiler and the distillation tower.

[0013] As a preferred solution, the top of the recovery tower is connected to the recovery tower reboiler through a recovery tower gas phase pipeline, and a compressor three is provided on the recovery tower gas phase pipeline.

[0014] As a preferred solution, the output end of the recovery tower reboiler is connected to the recovery tower reflux device through a recovery tower reboiler output pipeline, and a recovery tower cooler is provided on the recovery tower reboiler output pipeline.

[0015] As a preferred solution, the recovery tower reboiler output pipeline passes through the reaction tower feed preheater.

[0016] As a preferred embodiment, the recovery tower reflux device includes a recovery tower reflux tank, the bottom of the recovery tower reflux tank is connected to the recovery tower through a recovery tower reflux pipeline, the recovery tower reflux pipeline is connected to recovery tower reflux pipeline 1, and the recovery tower reflux pipeline 1 is connected to the distillation tower.

[0017] As a preferred solution, the bottom of the distillation tower is connected to the recovery tower through a distillation tower kettle extraction pipeline, and a recovery tower feed preheater is provided on the distillation tower kettle extraction pipeline.

[0018] As a preferred solution, the recovery tower reboiler output pipeline passes through the recovery tower feed preheater.

[0019] This application has the following advantages:

[0020] 1. Energy saving and consumption reduction: The present invention significantly reduces the steam consumption in the recovery section. No steam is required, only electricity is used. It is suitable for areas with high steam prices and low electricity prices.

[0021] 2. Improve thermal efficiency: This application effectively uses the methanol vapor from the top of the distillation tower to feed the reaction tower and its own distillation tower reboiler. At the same time, the methanol vapor from the top of the recovery tower is pressurized and heated by the compressor to provide a heat source for its own reboiler. The remaining heat is used to preheat the feed of the reaction tower and the recovery tower, thereby achieving efficient recovery and utilization of heat energy and improving the thermal efficiency of the entire process.

[0022] 3. Optimize the process flow: This application optimizes the process flow and reduces unnecessary energy consumption by controlling the heat supply of the reaction tower and the distillation tower, as well as the methanol vapor utilization of the recovery tower;

[0023] 4. Improve product purity: The purity of the refined alcohol obtained from the top of the distillation tower is as high as ≥99.99%, ensuring the high quality of the product;

[0024] 5. Reduce overall energy consumption: Compared with the currently more advanced three-tower two-heat pump process, this application significantly reduces the steam consumption of the entire process to 0.55 tons of steam per ton of sodium methoxide, effectively reducing overall energy consumption (Note: 1 kilowatt-hour of electricity is equivalent to 0.123 kilograms of standard coal or 0.0013 tons of steam).

[0025] 6. Environmental benefits: By reducing steam consumption and optimizing energy utilization, it helps reduce greenhouse gas emissions and has positive environmental benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of the structure of this application;

[0027] 1. Reaction tower; 2. Distillation tower; 3. Recovery tower; 4. Feed pipeline; 5. Reactor feed preheater; 6. Reaction tower top extraction pipeline; 7. Reaction tower kettle extraction pipeline; 8. Flash tank; 9. Sodium methoxide extraction pipeline; 10. Solid sodium methoxide product pump; 11. Flash tank gas phase pipeline; 12. Condenser; 13. Reaction tower kettle extraction pipeline 1; 14. Cooler; 15. Intermediate tank; 16. Methanol extraction pipeline; 17. Methanol transfer pump; 18. Rectification tower kettle extraction pipeline; 19. Reboiler circulation pump; 20. Distillation tower intermediate tank; 21. Rectification tower kettle pump; 22. Recovery tower feed preheater; 23. Tail gas pipeline; 24. Wastewater extraction pipeline; 25. Wastewater extraction pump; 26. Distillation tower reboiler; 27. Recovery tower reboiler; 28. Reaction tower reboiler; 29. ​​Distillation tower gas phase pipeline one; 30. Compressor one; 31. Distillation tower gas phase pipeline two; 32. Compressor two; 33. Distillation tower reboiler output pipeline; 34. Distillation tower cooler; 35. Distillation tower reflux tank; 36. Recovery tower gas phase pipeline; 37. Compressor three; 38. Recovery tower reboiler output pipeline; 39. Recovery tower cooler; 40. Distillation tower steam reboiler; 41. Recovery tower steam reboiler; 42. Recovery tower reflux tank; 43. Recovery tower reflux pipeline; 44. Recovery tower reflux pipeline one; 45. Reflux pump; 46. Recovery tower reflux extraction pump. DETAILED DESCRIPTION

[0028] The following is combined with Figure 1 The specific implementation of the present invention is described in detail. It should be noted that the specific implementation described herein is only used to illustrate and explain the present invention, and is not used to limit the present invention.

[0029] Example 1:

[0030] This embodiment provides a methanol energy-saving recovery device, comprising a reaction tower 1, a distillation tower 2, and a recovery tower 3 connected in sequence. The temperature at the top of the reaction tower 1 is 85°C and the pressure is 130KPa. The temperature at the top of the distillation tower 2 is 65°C and the pressure is 103KPa. The mass flow rate of the substance flowing out of the top of the distillation tower per unit time is 32047Kg / h; the temperature at the top of the recovery tower 3 is 65.6°C, and the mass flow rate of the substance flowing out of the top of the recovery tower per unit time is 2000Kg / h; the reaction tower 1 is connected to a feed pipeline 4, and a reaction line is provided on the feed pipeline 4. The material at about 40°C is heated to 60°C-80°C by the reaction tower feed preheater 5 and then enters the reaction tower 1; the top of the reaction tower 1 is connected to the distillation tower 2 through the reaction tower top extraction pipeline 6, and the methanol water vapor extracted from the top of the reaction tower 1 enters the distillation tower 2 for distillation; the bottom of the reaction tower 1 is connected to the reaction tower kettle extraction pipeline 7, the reaction tower kettle extraction pipeline 7 is connected to the flash tank 8, and the bottom of the flash tank 8 is connected to the sodium methoxide extraction pipeline 9, and the sodium methoxide extraction pipeline 9 is provided with a solid sodium methoxide product pump 10, and the top of the flash tank 8 is provided with a sodium methoxide extraction pipeline 9. There is a flash tank gas phase pipeline 11, and a condenser 12 is provided on the flash tank gas phase pipeline 11; the reaction tower kettle extraction pipeline 7 is connected to the reaction tower kettle extraction pipeline 13, and the reaction tower kettle extraction pipeline 13 is provided with a cooler 14, and the reaction tower kettle extraction pipeline 13 is connected to the intermediate tank 15, and a methanol extraction pipeline 16 is provided at the bottom of the intermediate tank 15, and a methanol delivery pump 17 is provided on the methanol extraction pipeline 16; the reaction tower 1 reactor extracts a 105°C mixed solution of 30% sodium methoxide and methanol solution, enters the flash tank 8 through the reaction tower kettle extraction pipeline 7, and passes through the flash tank The solid sodium methoxide after flash evaporation is transported to the solid workshop, etc. through the sodium methoxide extraction pipeline 9. The methanol vapor after flash evaporation is condensed by the condenser 12 and then sent to the alkali preparation tank to recover the methanol therein, thereby realizing the recycling of resources and reducing production costs. In addition, through condensation recovery, the emission of methanol can be reduced, which meets environmental protection requirements; the reactor of the reaction tower 1 extracts a 105°C mixed solution of 30% sodium methoxide and methanol solution, enters the reactor extraction pipeline 13 of the reaction tower, is cooled by the cooler 14, and then enters the intermediate tank 15 for buffering. The liquid methanol in the intermediate tank 15 is extracted through the methanol extraction pipeline 16 and then sent to the tank area.

[0031] The bottom of the distillation tower 2 is connected to the recovery tower 3 through the distillation tower kettle extraction pipeline 18. The distillation tower kettle extraction pipeline 18 is sequentially provided with a reboiler circulation pump 19, a distillation tower intermediate tank 20, a distillation tower kettle pump 21, and a recovery tower feed preheater 22. The reboiler circulation pump 19 is used to ensure that there is always sufficient fluid flow in the distillation tower reboiler 26 to ensure the normal operation of the distillation tower reboiler 26; the distillation tower intermediate tank 20 is connected to the tail gas pipeline 23; the methanol aqueous solution generated by the tail gas and the methanol aqueous solution extracted from the distillation tower 2 kettle are mixed in the distillation tower intermediate tank 20, and then preheated by the recovery tower feed preheater 22 before entering the recovery tower 3;

[0032] The bottom of the recovery tower 3 is provided with a wastewater extraction pipeline 24, and the wastewater extraction pipeline 24 is provided with a wastewater extraction pump 25. The bottom of the recovery tower 3 extracts wastewater, and the temperature of the wastewater is about 103°C.

[0033] The tower kettles of the distillation tower 2 and the recovery tower 3 are respectively provided with a distillation tower reboiler 26 and a recovery tower reboiler 27. The temperature of the material in the tower kettle of the distillation tower 2 entering the distillation tower reboiler 26 is 83°C and the pressure is 203kPa. The temperature of the material after being heated by the distillation tower reboiler 26 entering the tower kettle of the distillation tower 2 is 73.5°C and the pressure is 113kPa. The distillation tower reboiler 26 and the recovery tower reboiler 27 preferably adopt falling film reboilers. The tower kettle of the reaction tower 1 is provided with a reaction tower reboiler 28. The reaction tower reboiler 28 adopts a coil reboiler. When the reaction heat of the reaction tower 1 is insufficient, the heat is supplemented by steam. By precisely controlling the coil reboiler of the tower kettle of the reaction tower 1, the reaction heat of the reaction tower 1 is effectively supplemented, thereby reducing steam consumption. The top of the distillation tower 2 is connected to the bottom of the reaction tower 1 through a distillation tower gas phase pipeline-29, and a compressor-30 is provided on the distillation tower gas phase pipeline-29; the gas phase part of the refined methanol at the top of the distillation tower 2 is compressed and heated by the compressor-30 to provide heat for the bottom of the reaction tower 1, that is, the heat of the reaction tower 1 mainly comes from the steam of the methanol at the top of the distillation tower 2, which is pressurized to 153kPa by the compressor-30 and heated to 90-105°C. The mass flow rate of refined methanol flowing out of the distillation tower gas phase pipeline-29 per unit time is 14567kg / h, and the accuracy of refined methanol is 99.99%, which serves as a heat source and promotes the reaction of methanol and alkali to produce sodium methoxide; the distillation tower gas phase pipeline-29 is connected to the distillation tower Gas phase line 2 31, the distillation tower gas phase line 2 31 is connected to the distillation tower reboiler 26, the distillation tower gas phase line 2 31 is provided with a compressor 2 32, the output end of the distillation tower reboiler 26 is connected to the upper part of the distillation tower 2 through the distillation tower reboiler output pipeline 33, the distillation tower reboiler output pipeline 33 between the distillation tower reboiler 26 and the distillation tower 2 is provided with a distillation tower cooler 34, a distillation tower reflux tank 35, and a reflux pump 45 in sequence; the refined methanol gas phase part of the top of the distillation tower 2 is pressurized to 203kPa by the compressor 2 32 and heated to 128°C. The mass flow rate of refined methanol flowing out of the distillation tower gas phase line 2 31 per unit time is 17480kg / h, and the precision of refined methanol is 99.99%; compression After the temperature is raised, heat is provided to the distillation tower reboiler 26 to meet the heat demand of the distillation tower reboiler 26. The temperature of the condensate condensed by the distillation tower reboiler 26 is 46°C and the pressure is 403 kPa in the distillation tower reboiler output pipeline 33 after passing through the distillation tower cooler 34, the distillation tower reflux tank 35, and the reflux pump 45. The mass flow rate of the refined methanol flowing out of the distillation tower reboiler output pipeline 33 is 17480 kg / h, and the accuracy of the refined methanol is 99.99%; the refined methanol in the distillation tower reboiler output pipeline 33 is refluxed to the top of the distillation tower 2, so that the purity of the refined alcohol obtained at the top of the distillation tower 2 reaches ≥99.99%, and the bottom of the distillation tower 2 produces a methanol aqueous solution of 70%-75%, which is sent to the recovery tower 3 for methanol recovery.

[0034] The top of the recovery tower 3 is connected to the recovery tower reboiler 27 through the recovery tower gas phase pipeline 36, and a compressor three 37 is provided on the recovery tower gas phase pipeline 36. The output end of the recovery tower reboiler 27 is connected to the recovery tower reflux device through the recovery tower reboiler output pipeline 38, and a recovery tower cooler 39 is provided on the recovery tower reboiler output pipeline 38. The gas phase at the top of the recovery tower 3 is compressed and heated by the compressor three 37 to provide heat for the recovery tower reboiler 27, thereby realizing efficient recovery and utilization of thermal energy. The refined alcohol condensate condensed by the recovery tower cooler 39 is refluxed to the recovery tower reflux device; in the recovery stage of the recovery tower 3, there are two main energy-saving measures, one is to reduce steam consumption by using the compressor three 37, and the other is to reduce steam consumption by increasing thermal coupling to reduce steam consumption; the direct reflux and compression heating technology of the methanol vapor at the top of the recovery tower 3 reduces steam consumption, improves methanol recovery efficiency, and reduces overall energy consumption.

[0035] A distillation tower steam reboiler 40 is provided at the lower part of the distillation tower 2, and the distillation tower steam reboiler 40 is heated by steam; a recovery tower steam reboiler 41 is provided at the lower part of the recovery tower 3, and the recovery tower steam reboiler 41 is heated by steam; the distillation tower steam reboiler 40 and the recovery tower steam reboiler 41 are only used in the startup stage. After startup, the steam at the top of the distillation tower 2 is pressurized and heated by compressor 1 30 and compressor 2 32, and then provides heat to the bottom of the reaction tower 1 and the distillation tower reboiler 26 respectively. The steam at the top of the recovery tower 3 is pressurized and heated by compressor 3 37, and then directly provides heat to the recovery tower reboiler 27. No additional steam supply is needed, and heat self-sufficiency is achieved.

[0036] Example 2:

[0037] This embodiment describes the recovery tower reflux device, specifically:

[0038] The recovery tower reflux device includes a recovery tower reflux tank 42, the recovery tower reboiler output pipeline 38 is connected to the recovery tower reflux tank 42, the bottom of the recovery tower reflux tank 42 is connected to the recovery tower 3 through the recovery tower reflux pipeline 43, and the recovery tower reflux pipeline 43 is provided with a recovery tower reflux extraction pump 46; the recovery tower reflux pipeline 43 is connected to the recovery tower reflux pipeline-44, the temperature of the refined methanol in the recovery tower reflux pipeline-44 is 60°C, the accuracy of the refined methanol is 99.9%, the mass flow rate of the refined methanol flowing out of the recovery tower reflux pipeline-44 is 902 kg / h, and the reflux tower reflux pipeline-44 is connected to the distillation tower 2; the steam cooled by the recovery tower cooler 39 refluxes to the recovery tower reflux tank 42, and the liquid phase in the recovery tower reflux tank 42 partially refluxes to the recovery tower 3, and partially refluxes to the distillation tower 2; the recovery tower 3 in the recovery section does not need to consume steam, only electricity, and is suitable for areas with high steam prices and low electricity prices. From the perspective of comprehensive energy consumption, the steam consumption of the entire alkaline method for producing sodium methoxide in this application is 0.55 tons of steam / ton of sodium methoxide (electricity consumption converted into steam); compared with the currently more advanced three-tower two-heat pump process (steam consumption of 1.0 tons / ton of sodium methoxide), the energy consumption is significantly reduced.

[0039] In order to make more effective use of the heat of the recovery tower 3, the recovery tower 3 passes through the recovery tower feed preheater 22 and the reaction tower feed preheater 5 in turn, exchanges heat with the recovery tower feed preheater 22 and the reaction tower feed preheater 5 in turn, and then flows back to the recovery tower reflux tank 42; this application adopts innovative and efficient energy-saving technology to significantly improve the recovery efficiency of methanol, reduce energy consumption, and optimize the overall production process.

[0040] This application is mainly divided into three sections: reaction section, distillation section, and methanol recovery section, which realizes the production of sodium methoxide and the recovery and reuse of methanol.

[0041] In the reaction section, the heat of the reaction tower 1 mainly comes from the methanol vapor at the top of the distillation tower 2 in the distillation section. This vapor is pressurized and heated by compressor 30, serving as a heat source and promoting the reaction of methanol and alkali to produce sodium methoxide.

[0042] The heat energy of the distillation tower 2 in the distillation section mainly relies on the methanol vapor at the top of the distillation tower 2. Part of the vapor is heated by the compressor 2 32 and used in the distillation tower reboiler 26 to meet its own heat demand. The condensed liquid condensed by the distillation tower reboiler 26 is refluxed to the top of the distillation tower 2, so that the purity of the refined alcohol obtained at the top of the distillation tower 2 reaches ≥99.99%. The bottom of the tower produces a 70%-75% methanol aqueous solution, which is sent to the recovery tower 3 of the recovery section for methanol recovery.

[0043] In the recovery section, energy-saving measures are mainly achieved in two ways: one is to use compressor three 37 to reduce steam consumption, and the other is to reduce steam consumption by increasing thermal coupling; the methanol vapor at the top of recovery tower 3 is pressurized and heated by compressor three 37 to provide a heat source for the recovery tower reboiler 27 in the bottom of recovery tower 3, meeting the heat demand of the recovery tower reboiler 27, and the refined alcohol condensate condensed by the recovery tower reboiler 27 is partially refluxed to the recovery tower 3, and partially refluxed to the distillation tower 2; the recovery section does not require steam consumption, only electricity, and is suitable for areas with high steam prices and low electricity prices.

[0044] The present application realizes the recovery of methanol in the recovery tower without consuming steam, which has the effect of energy saving. In addition, it not only improves the energy efficiency and product quality of sodium methoxide production, but also reduces production costs, and also plays a positive role in environmental protection.

[0045] This application has the following advantages:

[0046] 1. Energy saving and consumption reduction: The present invention significantly reduces the steam consumption in the recovery section. No steam is required, only electricity is used. It is suitable for areas with high steam prices and low electricity prices.

[0047] 2. Improved thermal efficiency: This application effectively uses the methanol vapor from the top of the distillation tower to feed the reaction tower and its own distillation tower reboiler, thereby improving the thermal efficiency of the entire process. At the same time, the methanol vapor from the top of the recovery tower is pressurized and heated by the compressor to provide a heat source for its own reboiler, and the remaining heat is used to preheat the feed to the reaction tower and recovery tower, thereby achieving efficient recovery and utilization of heat energy and improving the thermal efficiency of the entire process.

[0048] 3. Optimize the process flow: This application optimizes the process flow and reduces unnecessary energy consumption by controlling the heat supply of the reaction tower and the distillation tower, as well as the methanol vapor utilization of the recovery tower;

[0049] 4. Improve product purity: The purity of the refined alcohol obtained from the top of the distillation tower is as high as ≥99.99%, ensuring the high quality of the product;

[0050] 5. Reduce overall energy consumption: Compared with the currently more advanced three-tower two-heat pump process, this application significantly reduces the steam consumption of the entire process to 0.55 tons of steam per ton of sodium methoxide, effectively reducing overall energy consumption (Note: 1 kilowatt-hour of electricity is equivalent to 0.123 kilograms of standard coal or 0.0013 tons of steam).

[0051] 6. Environmental benefits: By reducing steam consumption and optimizing energy utilization, it helps reduce greenhouse gas emissions and has positive environmental benefits;

[0052] 7. The equipment uses mature reaction towers, distillation towers, and recovery towers with simple structures, which makes the installation, commissioning, and maintenance of the equipment easy; mature equipment is not prone to failure, ensuring the stability and continuity of production.

[0053] The preferred embodiment of the present application is described in detail above in conjunction with the accompanying drawings. However, the present application is not limited to the specific details in the above-mentioned embodiments. Within the technical concept of the present application, various simple modifications can be made to the technical solution of the present application, and these simple modifications all fall within the scope of protection of the present application.

[0054] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any appropriate manner unless there is any contradiction. In order to avoid unnecessary repetition, the various possible combinations of this application will not be described separately.

[0055] In addition, the various implementation methods of the present application can be arbitrarily combined, as long as they do not violate the concept of the present application, and they should also be regarded as the contents disclosed in the present application.

Claims

1. A methanol energy-saving recovery device, comprising a reaction tower (1), a distillation tower (2), and a recovery tower (3) connected in sequence, wherein the distillation tower (2) and the recovery tower (3) are respectively provided with a distillation tower reboiler (26) and a recovery tower reboiler (27), and the reactor of the reaction tower (1) is provided with a reaction tower reboiler (28); characterized in that: The top of the distillation tower (2) is connected to the reactor of the reaction tower (1) through a distillation tower gas phase pipeline (29), a compressor (30) is provided on the distillation tower gas phase pipeline (29), the distillation tower gas phase pipeline (29) is connected to a distillation tower gas phase pipeline (31), the distillation tower gas phase pipeline (31) is connected to a distillation tower reboiler (26), and a compressor (32) is provided on the distillation tower gas phase pipeline (31); the output end of the distillation tower reboiler (26) is connected to the upper part of the distillation tower (2) through a distillation tower reboiler output pipeline (33), and the distillation tower reboiler ( A rectifying tower cooler (34), a rectifying tower reflux tank (35), and a reflux pump (45) are sequentially arranged on the rectifying tower reboiler output pipeline (33) between the rectifying tower (26) and the rectifying tower (2); the top of the recovery tower (3) is connected to the recovery tower reboiler (27) through a recovery tower gas phase pipeline (36), a compressor three (37) is arranged on the recovery tower gas phase pipeline (36), the output end of the recovery tower reboiler (27) is connected to the recovery tower reflux device through a recovery tower reboiler output pipeline (38), and a recovery tower cooler (39) is arranged on the recovery tower reboiler output pipeline (38).

2. A methanol energy-saving recovery device according to claim 1, characterized in that: The reaction tower (1) is connected to a feed pipeline (4), and a reaction tower feed preheater (5) is provided on the feed pipeline (4).

3. A methanol energy-saving recovery device according to claim 1, characterized in that: The recovery tower reboiler output line (38) passes through the reaction tower feed preheater (5).

4. A methanol energy-saving recovery device according to claim 1, characterized in that: The recovery tower reflux device comprises a recovery tower reflux tank (42), the bottom of the recovery tower reflux tank (42) is connected to the recovery tower (3) via a recovery tower reflux pipeline (43), the recovery tower reflux pipeline (43) is connected to a recovery tower reflux pipeline 1 (44), and the recovery tower reflux pipeline 1 (44) is connected to a distillation tower (2).

5. A methanol energy-saving recovery device according to claim 1, characterized in that: The bottom of the distillation tower (2) is connected to the recovery tower (3) through a distillation tower kettle extraction pipeline (18), and a recovery tower feed preheater (22) is provided on the distillation tower kettle extraction pipeline (18).

6. A methanol energy-saving recovery device according to claim 1, characterized in that: The recovery tower reboiler output line (38) passes through the recovery tower feed preheater (22).

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