Three-tower triple-effect methanol rectification device
By designing a three-tower, three-effect methanol distillation device, the synergistic effect of high-temperature react gas and saturated steam is used to solve the problems of low heat source utilization efficiency and high energy consumption in the prior art, and efficient methanol purification and energy-saving effects are achieved.
Patent Information
- Application Number
- CN202421918000.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-08
- Publication Date
- 2025-05-16
- Estimated Expiration
- 2034-08-08
AI Technical Summary
The existing methanol distillation technology has the problems of low heat source utilization efficiency and high energy consumption, and a new distillation device that can improve heat source utilization efficiency and reduce equipment energy consumption.
A three-column and three-effect methanol distillation device is designed, including a pre-distillation tower, a pressurized distillation tower and an atmospheric distillation tower, so as to achieve the purification and energy-saving effect of methanol through synergistic action. Specific measures include setting up a main reboiler at the bottom of the pressurized distillation tower, directly using the high-temperature reaction gas at the outlet of the methanol synthesis tower as a heat source, and combining low-pressure saturated steam as a supplementary heat source, making full use of heat and reducing heat loss.
Through the design of this device, the heat source utilization efficiency is improved, the heat is maximized and reasonable distribution is maximized, the equipment energy consumption is effectively reduced, and the purity and quality of methanol products are improved.
Smart Images
Figure CN222871371U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of methanol distillation, in particular to a three-tower three-effect methanol distillation device. Background Art
[0002] Distillation is an important separation operation unit in the petrochemical industry, and it is also a relatively energy-consuming unit operation process. In order to reduce its energy consumption, a variety of measures can be adopted. At present, the mainstream process flows in China include double-tower single-effect, three-tower double-effect, four-tower double-effect, five-tower triple-effect, etc. The investment and energy consumption of different process flows vary greatly, and the choice of process must meet the needs of downstream products. Therefore, according to the actual situation of the device, choosing a more reasonable, energy-saving and efficient methanol distillation device, while continuously optimizing production operations, plays an important role in reducing the cost of methanol production and improving product competitiveness. Utility Model Content
[0003] The utility model aims to provide a three-tower three-effect methanol distillation device to solve the problems existing in the above-mentioned prior art, improve the utilization efficiency of heat source, maximize the reasonable distribution of heat, and effectively reduce the energy consumption of equipment.
[0004] To achieve the above purpose, the utility model provides the following solutions:
[0005] The utility model provides a three-tower three-effect methanol distillation device, comprising a pre-distillation tower, a pressure distillation tower and an atmospheric distillation tower; the pre-distillation tower is provided with a material inlet, and the material inlet is used to receive crude methanol generated by a methanol synthesis tower; the tower bottom outlet of the pre-distillation tower can be connected with the feed inlet of the pressure distillation tower through a first tower bottom reboiler; the tower top of the pressure distillation tower is provided with a second tower top separator; the tower bottom outlet of the pressure distillation tower can be connected with the feed inlet of the atmospheric distillation tower through a second tower bottom main reboiler and a second tower bottom supplementary reboiler in sequence The bottom outlet of the atmospheric distillation tower is connected with a third bottom reboiler; a part of the gas phase at the top outlet of the pressurized distillation tower is connected with the second top separator via the first bottom reboiler, and another part of the gas phase is connected with the second top separator via the third bottom reboiler; the heat source of the second bottom main reboiler is the high-temperature reaction gas at the outlet of the methanol synthesis tower; the heat source of the second bottom supplementary reboiler is saturated steam; the second top separator and the top outlet of the atmospheric distillation tower can produce methanol products.
[0006] Preferably, the liquid separated by the second tower top separator flows back into the pressurized distillation tower; the gas phase separated by the second tower top separator and the gas phase at the tower top outlet of the atmospheric distillation tower are both connected and communicated with the methanol storage tank after passing through a methanol cooler.
[0007] Preferably, the outlet of the first bottom reboiler is connected to the first bottom separator; the gas phase separated by the first bottom separator is passed into the pre-distillation tower; the liquid separated by the first bottom separator is passed into the feed port of the pressurized distillation tower.
[0008] Preferably, the outlet of the second bottom supplementary reboiler is connected to a second bottom separator; the gas phase separated by the second bottom separator is passed into the pressurized distillation tower; the liquid separated by the second bottom separator is passed into the feed port of the atmospheric distillation tower.
[0009] Preferably, the outlet of the third bottom reboiler is connected to a third bottom separator; the gas phase separated by the third bottom separator is passed into the atmospheric distillation tower; and the liquid separated by the third bottom separator is passed into a wastewater treatment device.
[0010] Preferably, the top outlet of the pre-distillation tower is connected to the first top condenser and the first top separator in sequence; the non-condensable gas separated by the first top separator is sent to the VOC recovery and processing equipment; the liquid separated by the first top separator is refluxed into the pre-distillation tower.
[0011] Preferably, the liquid separated by the first bottom separator is introduced into the feed inlet of the pressurized distillation tower after passing through a booster pump.
[0012] Preferably, the top outlet of the atmospheric distillation tower is connected to a third top condenser and a third top separator in sequence; the gas phase separated by the third top separator is passed into the methanol storage tank after passing through the methanol cooler; and the liquid separated by the third top separator is refluxed into the atmospheric distillation tower.
[0013] Preferably, the methanol cooler comprises a first cooler and a second cooler; the gaseous phase separated by the second tower top separator is passed into the methanol storage tank via the first cooler; and the gaseous phase separated by the third tower top separator is passed into the methanol storage tank via the second cooler.
[0014] Compared with the prior art, the utility model has achieved the following technical effects:
[0015] The three-tower three-effect methanol distillation device provided by the utility model realizes the purification and energy-saving effects of methanol through the synergistic effect among the pre-distillation tower, the pressurized distillation tower and the atmospheric distillation tower; the high-temperature reaction gas at the outlet of the methanol synthesis tower of the methanol synthesis unit is directly used in the main reboiler at the bottom of the second tower to exchange heat with the liquid at the bottom outlet of the pressurized distillation tower. Compared with the traditional method of first exchanging the high-temperature reaction gas with water to form saturated steam, and then using the saturated steam to exchange heat with the liquid at the bottom outlet of the pressurized distillation tower, the utility model can directly utilize the heat of the high-temperature reaction gas, reduce heat loss, and improve energy utilization efficiency; and because the high-temperature reaction gas comes from the methanol synthesis tower, this design ensures the close connection between the distillation process and the synthesis process, making the entire production process more continuous and stable; and the high-temperature reaction gas is used as the main heat exchange heat source, and low-pressure saturated steam is used in combination with the second tower bottom The supplementary reboiler is used as a supplementary heat source. When the liquid temperature does not reach the process requirement temperature, saturated steam can be used as a supplementary heat source for heat exchange. In actual production, it can be adjusted according to the production situation, and the operability is strong. The gas phase at the top outlet of the pressurized distillation tower is generally 120°C, the liquid at the bottom outlet of the pre-distillation tower is generally 75°C, and the liquid at the bottom outlet of the atmospheric distillation tower is generally 100°C. There is a certain heat exchange temperature difference among the three. By passing the gas phase at the top outlet of the pressurized distillation tower through the first bottom reboiler and the third bottom reboiler for heat exchange, it can fully utilize the heat, so that the top outlet of the pressurized distillation tower does not need to be equipped with a condenser, reducing the investment in heat exchange equipment, and reducing the amount of steam and circulating cooling water; the overall efficiency of heat source utilization can be improved, the heat can be reasonably distributed to the maximum extent, and the energy consumption of equipment can be effectively reduced.
[0016] Furthermore, the gaseous phase separated by the second tower top separator and the gaseous phase at the tower top outlet of the atmospheric distillation tower can be quickly condensed into liquid methanol through a methanol cooler. This process is efficient and continuous, which helps to ensure the collection efficiency of methanol. Rapid condensation reduces the residence time of methanol gas, thereby reducing losses caused by leakage, etc. Methanol is a flammable and explosive substance. Rapidly condensing its gas into liquid and storing it in a sealed storage tank can reduce the risk of explosion and facilitate operations such as inventory management, temperature control and pressure monitoring.
[0017] Furthermore, the provision of the first bottom separator can improve the purity of the material entering the pressurized distillation tower, reduce the accumulation of internal impurities, and improve the distillation separation efficiency; and the reflux of the gas phase into the pre-distillation tower can maintain the stable operation of the pre-distillation tower and reduce system fluctuations caused by feed fluctuations or changes in operating conditions.
[0018] Furthermore, the setting of the second bottom separator can allow the separated gas phase to flow back into the pressurized distillation tower, thereby increasing the contact time and contact area between the gas and liquid phases in the tower, which is beneficial to further separation between low-boiling point components and high-boiling point components, and helps to improve the purity and quality of the methanol product.
[0019] Furthermore, the liquid portion separated by the third tower bottom separator is sent to a wastewater treatment device, which can effectively remove harmful substances and pollutants therein, ensuring that the wastewater meets environmental protection standards before discharge, helping to reduce environmental pollution and protect the ecological environment; and in the wastewater treatment process, it is also possible to consider recycling and reusing valuable substances to improve resource utilization; the separated gas phase is refluxed to the atmospheric distillation tower, and the useful components in these gas phases can be further utilized to improve the distillation efficiency. At the same time, the low-boiling point components in the reflux gas phase can be more fully transferred to the liquid in the tower for mass and heat transfer, which helps to achieve more refined separation and improve the purity and quality of the product.
[0020] Furthermore, through the dual effects of the first top condenser and the first top separator, the condensable components in the gas phase at the top outlet of the pre-distillation tower are effectively condensed into liquid and refluxed into the pre-distillation tower, thereby achieving deep separation from the light components, which helps to improve the purity and efficiency of the subsequent distillation process; the condensation reflux process helps to remove impurities and unnecessary components in the mixture, thereby improving the quality and purity of the final product; the non-condensable gas is sent to the VOC recovery and treatment equipment, thereby realizing the resource utilization of volatile organic compounds, which can not only reduce the waste of resources, but also bring additional economic benefits to the enterprise; sending the non-condensable gas to the VOC recovery and treatment equipment can significantly reduce the amount of volatile organic compounds emitted into the atmosphere, which helps to reduce environmental pollution and protect the ecological environment and human health; through effective condensation reflux and VOC recovery treatment, the material composition and process parameters in the pre-distillation tower can be kept stable, thereby improving the stability and reliability of the entire production process.
[0021] Furthermore, the liquid at the bottom outlet of the pre-distillation tower is rich in high-boiling point components and target products. After these liquids are sent to the pressurized distillation tower through a booster pump, they are further separated at a higher pressure and temperature, so that the high-boiling point components can be fully separated and purified, thereby improving the purity and yield of the product.
[0022] Furthermore, the purity of methanol can be improved by condensing and separating the gaseous phase at the top outlet of the atmospheric distillation tower.
[0023] Furthermore, the second tower top separator and the third tower top separator are respectively connected to the first cooler and the second cooler, so as to facilitate the condensation of gaseous methanol into liquid methanol, thereby facilitating the collection and storage of methanol. BRIEF DESCRIPTION OF THE DRAWINGS
[0024] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.
[0025] Figure 1 The utility model provides a three-tower three-effect methanol distillation device with a process flow diagram.
[0026] In the figure:
[0027] 100-Three-tower, three-effect methanol distillation unit;
[0028] 10-pre-distillation tower; 11-first tower bottom reboiler; 12-first tower bottom separator; 13-boosting pump; 14-first tower top condenser; 15-first tower top separator;
[0029] 20-pressure distillation tower; 21-second tower bottom main reboiler; 22-second tower bottom supplementary reboiler; 23-second tower bottom separator; 24-second tower top separator;
[0030] 30-atmospheric distillation tower; 31-third tower bottom reboiler; 32-third tower bottom separator; 33-third tower top condenser; 34-third tower top separator;
[0031] 40-methanol storage tank; 41-first cooler; 42-second cooler. DETAILED DESCRIPTION
[0032] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.
[0033] The utility model aims to provide a three-tower three-effect methanol distillation device to solve the problems existing in the prior art, improve the utilization efficiency of heat sources, maximize the reasonable distribution of heat, and effectively reduce the energy consumption of equipment.
[0034] In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.
[0035] Embodiment 1
[0036] This embodiment provides a three-tower three-effect methanol distillation device 100, which is mainly but not limited to the use in the production of methanol from coke oven gas. Figure 1 As shown, it includes a pre-distillation tower 10, a pressure distillation tower 20 and an atmospheric distillation tower 30; the pre-distillation tower 10 is provided with a material inlet, and the material inlet is used to receive the crude methanol generated by the reaction of the methanol synthesis tower; the bottom outlet of the pre-distillation tower 10 can be connected with the feed inlet of the pressure distillation tower 20 through the first bottom reboiler 11; the top of the pressure distillation tower 20 is provided with a second top separator 24; the bottom outlet of the pressure distillation tower 20 can be connected with the feed inlet of the atmospheric distillation tower 30 through the second bottom main reboiler 21 and the second bottom supplementary reboiler 22 in sequence; the atmospheric distillation tower 30 is connected with the feed inlet of the atmospheric distillation tower 30 through the second bottom main reboiler 21 and the second bottom supplementary reboiler 22; The bottom outlet of the distillation tower 30 is connected to the third bottom reboiler 31; a part of the gas phase at the top outlet of the pressurized distillation tower 20 is connected to the second top separator 24 via the first bottom reboiler 11, and another part of the gas phase is connected to the second top separator 24 via the third bottom reboiler 31; the heat source of the second bottom main reboiler 21 is the high-temperature reaction gas at the outlet of the methanol synthesis tower; the heat source of the second bottom supplementary reboiler 22 is saturated steam; the second top separator 24 and the top outlet of the atmospheric distillation tower 30 can produce methanol products.
[0037] Through the synergistic effect between the pre-distillation tower 10, the pressure distillation tower 20 and the atmospheric distillation tower 30, the methanol purification and energy-saving effects are achieved; the high-temperature reaction gas at the outlet of the methanol synthesis tower of the methanol synthesis unit is directly used in the second tower bottom main reboiler 21 to exchange heat with the liquid at the bottom outlet of the pressure distillation tower 20. Compared with the traditional method of first exchanging the high-temperature reaction gas with water to form saturated steam, and then using the saturated steam to heat the liquid at the bottom outlet of the pressure distillation tower 20, it can directly utilize the heat of the high-temperature reaction gas, reduce heat loss, and improve energy utilization efficiency; and because its high-temperature reaction gas comes from the methanol synthesis tower, this design ensures the close connection between the distillation process and the synthesis process, making the entire production process more continuous and stable; and its high-temperature reaction gas is used as the main heat source for heat exchange, and low-pressure saturated steam is used in combination with the second tower bottom supplementary reboiler 22 as a supplementary heat source. Heat source, when its liquid temperature does not reach the process required temperature, saturated steam can be used as a supplementary heat source for heat exchange. In actual production, it can be adjusted according to production conditions, and the operability is strong; the gas phase at the top outlet of the pressurized distillation tower 20 is generally 120°C, the liquid at the bottom outlet of the pre-distillation tower 10 is generally 75°C, and the liquid at the bottom outlet of the atmospheric distillation tower 30 is generally 100°C. There is a certain heat exchange temperature difference between the three. By passing the gas phase at the top outlet of the pressurized distillation tower 20 through the first bottom reboiler 11 and the third bottom reboiler 31 for heat exchange, it can fully utilize the heat, so that the top outlet of the pressurized distillation tower 20 does not need to be equipped with a condenser, reducing the investment in heat exchange equipment, and reducing the amount of steam and circulating cooling water; improving the overall utilization efficiency of the heat source, maximizing the reasonable distribution of heat, and effectively reducing the energy consumption of equipment.
[0038] Specifically, the three-tower three-effect methanol distillation device 100 of this embodiment is based on the existing methanol three-tower distillation technology, and two reboilers are arranged at the bottom of the pressurized distillation tower 20, namely, the second tower bottom main reboiler 21 and the second tower bottom supplementary reboiler 22, wherein the second tower bottom main reboiler 21 directly uses the high-temperature reaction gas of the methanol synthesis tower as a heat source to heat the liquid distilled from the bottom outlet of the pressurized distillation tower 20; the second tower bottom supplementary reboiler 22 serves as a heat supplement for the second tower bottom main reboiler 21, and when the heat of the second tower bottom main reboiler 21 is insufficient, saturated steam is introduced to heat the liquid distilled from the bottom outlet of the pressurized distillation tower 20; the original reaction gas is first used to exchange heat with the circulating water to generate saturated steam, and then the saturated steam is used to heat the liquid. The process of saturated steam providing heat for liquid heat exchange at the bottom outlet of the pressurized distillation tower 20 can reduce the amount of steam required for methanol distillation, improve heat exchange efficiency, and reduce production costs; in terms of investment, it can be achieved by adding only one reboiler, with a small investment, and at the same time, the steam volume can be adjusted according to the heat situation of the reaction gas to keep the temperature stable during distillation; it has strong operability, and in the actual production process, according to the bottom and top temperatures of the pressurized distillation tower 20, the reaction gas circulation volume, the circulating water volume of the heat medium heat exchanger of the reaction gas and other parameters, the saturated steam flow rate of the second bottom supplementary reboiler 22 in the pressurized distillation tower 20 can be adjusted to control the temperature of the distillation tower, make full use of the heat of the reaction gas, and respond in time when the above process parameters change.
[0039] Among them, other relevant settings of the pre-distillation tower 10 are described as follows:
[0040] Among the optional solutions of this embodiment, it is more preferred that Figure 1 As shown, the top outlet of the pre-distillation tower 10 is connected in sequence to the first top condenser 14 and the first top separator 15; the non-condensable gas separated by the first top separator 15 is sent to the VOC recovery and processing equipment; the liquid separated by the first top separator 15 is refluxed into the pre-distillation tower 10. Through the dual effects of the first top condenser 14 and the first top separator 15, the condensable components in the gas phase at the top outlet of the pre-distillation tower 10 are effectively condensed into liquid and refluxed into the pre-distillation tower 10, achieving deep separation from the light components, which helps to improve the purity and efficiency of the subsequent distillation process; the condensation reflux process helps to remove impurities and unnecessary components in the mixture, thereby improving the quality and purity of the final product; the non-condensable gas is sent to the VOC recovery and treatment equipment, realizing the resource utilization of volatile organic compounds, which can not only reduce the waste of resources, but also bring additional economic benefits to the enterprise; sending the non-condensable gas to the VOC recovery and treatment equipment can significantly reduce the amount of volatile organic compounds emitted into the atmosphere, which helps to reduce environmental pollution and protect the ecological environment and human health; through effective condensation reflux and VOC recovery and treatment, the material composition and process parameters in the pre-distillation tower 10 can be kept stable, thereby improving the stability and reliability of the entire production process.
[0041] Among the optional solutions of this embodiment, it is more preferred that Figure 1 As shown, the outlet of the first bottom reboiler 11 is connected to the first bottom separator 12; the gas phase separated by the first bottom separator 12 is passed into the pre-distillation tower 10; the liquid separated by the first bottom separator 12 is passed into the feed port of the pressurized distillation tower 20. The provision of the first bottom separator 12 can improve the purity of the material entering the pressurized distillation tower 20, reduce the accumulation of internal impurities, and improve the distillation separation efficiency; and the gas phase reflux to the pre-distillation tower 10 can maintain the stable operation of the pre-distillation tower 10, reducing the system fluctuation caused by feed fluctuation or change in operating conditions.
[0042] Among the optional solutions of this embodiment, it is more preferred that Figure 1 As shown, the liquid separated by the first bottom separator 12 is passed through the booster pump 13 to the feed port of the pressure distillation tower 20. The liquid at the bottom outlet of the pre-distillation tower 10 is rich in high-boiling point components and target products. After these liquids are sent to the pressure distillation tower 20 by the booster pump 13, they are further separated at a higher pressure and temperature, so that the high-boiling point components can be fully separated and purified, thereby improving the purity and yield of the product.
[0043] Among them, other relevant settings of the pressurized distillation tower 20 are described as follows:
[0044] Among the optional solutions of this embodiment, it is more preferred that Figure 1 As shown, the liquid separated by the second tower top separator 24 flows back into the pressurized distillation tower 20; the gas phase separated by the second tower top separator 24 and the gas phase at the tower top outlet of the atmospheric distillation tower 30 (specifically, the gas phase separated by the third tower top separator 34) are connected and communicated with the methanol storage tank 40 after passing through the methanol cooler. The gas phase separated by the second tower top separator 24 and the gas phase at the tower top outlet of the atmospheric distillation tower 30 can be quickly condensed into liquid methanol through the methanol cooler. This process is efficient and continuous, which helps to ensure the collection efficiency of methanol; rapid condensation reduces the residence time of methanol gas, thereby reducing losses caused by leakage, etc.; methanol is a flammable and explosive substance. Rapidly condensing its gas into liquid and storing it in a sealed storage tank can reduce the risk of explosion and facilitate operations such as inventory management, temperature control and pressure monitoring.
[0045] Among the optional solutions of this embodiment, it is more preferred that Figure 1As shown, the outlet of the second tower bottom supplementary reboiler 22 is connected to the second tower bottom separator 23; the gas phase separated by the second tower bottom separator 23 is passed into the pressure distillation tower 20; the liquid separated by the second tower bottom separator 23 is passed into the feed port of the atmospheric distillation tower 30. The arrangement of the second tower bottom separator 23 enables the separated gas phase to flow back into the pressure distillation tower 20, thereby increasing the contact time and contact area of the gas-liquid two phases in the tower, which is beneficial to further separation between low boiling point components and high boiling point components, and helps to improve the purity and quality of the methanol product.
[0046] Among them, other relevant settings of the atmospheric distillation tower 30 are described as follows:
[0047] Among the optional solutions of this embodiment, it is more preferred that Figure 1 As shown, the top outlet of the atmospheric distillation tower 30 is connected to the third top condenser 33 and the third top separator 34 in sequence; the gas phase separated by the third top separator 34 is passed into the methanol storage tank 40 after passing through the methanol cooler; the liquid separated by the third top separator 34 is refluxed into the atmospheric distillation tower 30. The gas phase at the top outlet of the atmospheric distillation tower 30 can improve the purity of methanol after condensation and separation.
[0048] Among the optional solutions of this embodiment, it is more preferred that Figure 1 As shown, the outlet of the third tower bottom reboiler 31 is connected to the third tower bottom separator 32; the gas phase separated by the third tower bottom separator 32 is passed into the atmospheric distillation tower 30; the liquid separated by the third tower bottom separator 32 is passed into the wastewater treatment device. Sending the liquid part separated by the third tower bottom separator 32 to the wastewater treatment device can effectively remove the harmful substances and pollutants therein, ensure that the wastewater meets the environmental protection standards before discharge, help reduce environmental pollution and protect the ecological environment; and in the process of wastewater treatment, it is also possible to consider recycling and reusing valuable substances to improve resource utilization; the separated gas phase is refluxed to the atmospheric distillation tower 30, and the useful components in these gas phases can be further utilized to improve the distillation efficiency. At the same time, the low boiling point components in the reflux gas phase can be more fully transferred with the liquid in the tower. Heat transfer helps to achieve more refined separation and improve the purity and quality of the product.
[0049] Specifically, the atmospheric distillation tower 30 is provided with a discharge port for discharging fusel alcohol.
[0050] Among them, the relevant settings for methanol product collection are as follows:
[0051] Among the optional solutions of this embodiment, it is more preferred that Figure 1As shown, the methanol cooler includes a first cooler 41 and a second cooler 42; the gas phase separated by the second tower top separator 24 is passed into the methanol storage tank 40 through the first cooler 41; the gas phase separated by the third tower top separator 34 is passed into the methanol storage tank 40 through the second cooler 42. The second tower top separator 24 and the third tower top separator 34 are respectively connected to the first cooler 41 and the second cooler 42, so as to facilitate the condensation of gaseous methanol into liquid methanol, thereby facilitating the collection and storage of methanol.
[0052] Among them, regarding other related instructions:
[0053] Specific process description:
[0054] 1. The crude methanol from the methanol synthesis unit first enters the pre-distillation tower 10, and the gaseous phase distilled out of the tower top outlet is cooled by the first tower top condenser 14, and then separated in the first tower top separator 15. The liquid returns to the pre-distillation tower 10, and the non-condensable gas is sent to the VOC recovery and treatment equipment; the liquid distilled out of the tower bottom outlet enters the first tower bottom reboiler 11, and after heat exchange with the gaseous phase at the tower top outlet of the pressure distillation tower 20, it is separated in the first tower bottom separator 12, and the gaseous phase returns to the pre-distillation tower 10, and the liquid enters the pressure distillation tower 20 after being pressurized by the booster pump 13.
[0055] 2. The gaseous phase distilled from the top outlet of the pressure distillation tower 20 is divided into two branches, which flow through the first bottom reboiler 11 and the third bottom reboiler 31 respectively, and exchange heat with the liquid distilled from the bottom outlet of the pre-distillation tower 10 and the atmospheric distillation tower 30. After the heat exchange, it is separated in the second top separator 24, and the liquid returns to the pressure distillation tower 20. The gaseous phase is cooled by the first cooler 41 and then enters the methanol storage tank 40 for storage.
[0056] 3. The liquid distilled from the bottom outlet of the pressure distillation tower 20 is heated by the reaction gas from the outlet of the methanol synthesis tower in the second bottom main reboiler 21, and then passes through the second bottom supplementary reboiler 22 and the second bottom separator 23 in sequence; when the liquid temperature does not meet the process requirements, saturated steam is introduced into the second bottom supplementary reboiler 22 for heating, and after sufficient heat exchange, the gas phase is separated and returned to the pressure distillation tower 20, and the liquid enters the atmospheric distillation tower 30.
[0057] 4. The gaseous phase distilled from the top outlet of the atmospheric distillation tower 30 is cooled in the third top condenser 33, and the liquid separated by the third top separator 34 is returned to the atmospheric distillation tower 30. The gaseous phase enters the second cooler 42, condensed into a qualified refined methanol product and stored in the methanol storage tank 40. The liquid distilled from the bottom outlet of the atmospheric distillation tower 30 is heat exchanged with the gaseous phase distilled from the top outlet of the pressurized distillation tower 20 through the second bottom reboiler, and the gaseous phase separated by the third bottom separator 32 is returned to the atmospheric distillation tower 30. The liquid is wastewater and enters the wastewater treatment device for treatment.
[0058] Taking the coke oven gas to methanol project with an annual output of 120,000 tons of methanol as an example, the high-temperature reaction gas leaving the methanol synthesis tower is above 230°C, and the temperature of the distillate at the bottom of the pressurized distillation tower 20 is around 130°C. There is a heat exchange temperature difference. The two are heat exchanged through the main reboiler 21 at the bottom of the second tower. After the heat exchange, the reaction gas temperature is reduced to 142°C and the distillate temperature is increased to 136°C.
[0059] The reaction gas of the methanol synthesis tower exchanges heat with the circulating water, and the saturated steam generated after the circulating water is heated provides heat for the pressurized distillation tower 20. In this case, there is generally a 5% heat exchange loss; after adopting this device, about 0.7t / h of steam can be saved. In addition, when the output changes and the heat provided by the reaction gas of the methanol synthesis tower may be insufficient, in order to meet the temperature of the pre-distillation tower 10, the pressurized distillation tower 20, and the atmospheric distillation tower 30, it is necessary to use the second tower bottom supplementary reboiler 22 to supplement the heat and adjust the flow rate of its saturated steam to ensure the production of methanol products that meet the requirements.
[0060] The present invention uses specific examples to illustrate the principle and implementation of the present invention. The above examples are only used to help understand the method and core idea of the present invention. At the same time, for those skilled in the art, according to the idea of the present invention, there will be changes in the specific implementation and application scope. In summary, the content of this specification should not be understood as limiting the present invention.
Claims
1. A three-tower, three-effect methanol distillation device, characterized in that: It includes a pre-distillation tower, a pressure distillation tower and an atmospheric distillation tower; The pre-distillation tower is provided with a material inlet, and the material inlet is used to receive the crude methanol generated by the methanol synthesis tower; the bottom outlet of the pre-distillation tower can be connected to the feed inlet of the pressurized distillation tower through the first bottom reboiler; The top of the pressure distillation tower is provided with a second top separator; the bottom outlet of the pressure distillation tower can be connected to the feed inlet of the atmospheric distillation tower via the second bottom main reboiler and the second bottom supplementary reboiler in sequence; The bottom outlet of the atmospheric distillation tower is connected to a third bottom reboiler; A portion of the gas phase material at the top outlet of the pressurized distillation tower is communicated with the second top separator via the first bottom reboiler, and another portion of the gas phase material is communicated with the second top separator via the third bottom reboiler; The heat source of the second tower bottom main reboiler is the high temperature reaction gas at the outlet of the methanol synthesis tower; The heat source of the second tower bottom supplementary reboiler is saturated steam; The second tower top separator and the tower top outlet of the atmospheric distillation tower can produce methanol products.
2. The three-tower, three-effect methanol distillation device according to claim 1, characterized in that: The liquid separated by the second tower top separator flows back into the pressurized distillation tower; The gas phase separated by the second tower top separator and the gas phase at the tower top outlet of the atmospheric distillation tower are both connected and communicated with the methanol storage tank after passing through a methanol cooler.
3. The three-tower, three-effect methanol distillation device according to claim 1, characterized in that: The outlet of the first tower bottom reboiler is connected to a first tower bottom separator; The gas phase separated by the first bottom separator is introduced into the pre-distillation tower; The liquid separated by the first bottom separator is introduced into the feed inlet of the pressurized distillation tower.
4. The three-tower three-effect methanol distillation device according to claim 1, characterized in that: The outlet of the second tower bottom supplementary reboiler is connected to a second tower bottom separator; The gas phase separated by the second bottom separator is introduced into the pressurized distillation tower; The liquid separated by the second bottom separator is introduced into the feed inlet of the atmospheric distillation tower.
5. The three-tower three-effect methanol distillation device according to claim 1, characterized in that: The outlet of the third tower bottom reboiler is connected to a third tower bottom separator; The gas phase separated by the third bottom separator is introduced into the atmospheric distillation tower; The liquid separated by the third tower bottom separator is introduced into a wastewater treatment device.
6. The three-tower three-effect methanol distillation device according to claim 1, characterized in that: The top outlet of the pre-distillation tower is connected in sequence with a first top condenser and a first top separator; The non-condensable gas separated by the first tower top separator is sent to the VOC recovery and processing equipment; The liquid separated by the first tower top separator flows back into the pre-distillation tower.
7. The three-tower, three-effect methanol distillation device according to claim 3, characterized in that: The liquid separated by the first tower bottom separator is introduced into the feed inlet of the pressurized distillation tower after passing through a booster pump.
8. The three-tower, three-effect methanol distillation device according to claim 2, characterized in that: The top outlet of the atmospheric distillation tower is connected in sequence with a third top condenser and a third top separator; The gas phase separated by the third tower top separator is passed into the methanol storage tank after passing through the methanol cooler; The liquid separated by the third tower top separator flows back into the atmospheric distillation tower.
9. The three-tower, three-effect methanol distillation device according to claim 8, characterized in that: The methanol cooler comprises a first cooler and a second cooler; The gas phase separated by the second tower top separator is passed into the methanol storage tank through the first cooler; The gas phase separated by the third tower top separator is passed into the methanol storage tank through the second cooler.