A system for the production of methanol

Abstract

This invention discloses a methanol production system, comprising a compressor, a methanol synthesis tower, a gas-to-gas heat exchanger, a high-pressure reboiling assembly, a medium-pressure reboiling assembly, a vacuum reboiling assembly, and a water-cooled separation assembly. The compressor is connected to the gas-to-gas heat exchanger, which is connected to the top of the methanol synthesis tower, and the bottom of the methanol synthesis tower is connected to the gas-to-gas heat exchanger. The gas-to-gas heat exchanger, high-pressure reboiling assembly, medium-pressure reboiling assembly, vacuum reboiling assembly, and water-cooled separation assembly are sequentially connected, and the water-cooled separation assembly is connected to the compressor. The gas-to-gas heat exchanger, high-pressure reboiling assembly, medium-pressure reboiling assembly, vacuum reboiling assembly, and water-cooled separation assembly are respectively connected to a hydraulic turbine assembly. The vacuum distillation assembly, medium-pressure distillation assembly, and high-pressure distillation assembly all output refined methanol. This application significantly reduces energy consumption in the methanol distillation process, shortens the process, saves space, and reduces equipment investment.

Description

Technical Field

[0001] This utility model belongs to the field of methanol production, and in particular relates to a methanol production system. Background Technology

[0002] Methanol (CH3OH) is an important chemical feedstock and clean fuel, its production primarily relying on the chemical reaction of syngas (CO and H2) in the presence of a catalyst. Traditional production methods use natural gas, coal, or biomass as raw materials, producing syngas through steam reforming or gasification. Methanol is then synthesized at 200-300℃ and 50-100 bar using copper-based catalysts (such as Cu / ZnO / Al2O3). In recent years, technological advancements, particularly low-pressure processes and efficient reactors, have significantly improved production efficiency and economic benefits. Furthermore, emerging technologies such as direct methane synthesis, electrochemical methods (using renewable energy to electrolyze water to produce hydrogen and react it with CO2), and biological methods (using microorganisms to synthesize methanol) are continuously developing, providing more environmentally friendly and sustainable pathways for methanol production. These technological advancements have driven the widespread application of methanol in the chemical and energy sectors. Utility Model Content

[0003] In view of this, the present invention aims to provide a methanol production system to solve at least one technical problem in the background art.

[0004] To achieve the above objectives, the technical solution of this utility model is implemented as follows:

[0005] A methanol production system includes a compressor, a methanol synthesis tower, a gas-gas heat exchanger, a high-pressure reboiler assembly, a medium-pressure reboiler assembly, a vacuum reboiler assembly, a water-cooled separation assembly, a hydraulic turbine assembly, a purge gas assembly, a purification assembly, a vacuum distillation assembly, a medium-pressure distillation assembly, and a high-pressure distillation assembly.

[0006] The compressor is connected to the gas-to-gas heat exchanger, the gas-to-gas heat exchanger is connected to the top of the methanol synthesis tower, and the bottom of the methanol synthesis tower is connected to the gas-to-gas heat exchanger.

[0007] The gas-to-gas heat exchanger, high-pressure reboiler assembly, medium-pressure reboiler assembly, low-pressure reboiler assembly, and water-cooled separation assembly are connected in sequence, and the water-cooled separation assembly is connected to the compressor.

[0008] The gas-to-gas heat exchanger, high-pressure reboiler assembly, medium-pressure reboiler assembly, vacuum reboiler assembly, and water-cooled separation assembly are all connected to the hydraulic turbine assembly. The vacuum distillation assembly, medium-pressure distillation assembly, and high-pressure distillation assembly all output refined methanol.

[0009] Furthermore, the hydraulic turbine assembly is connected to the purge gas assembly; the hydraulic turbine assembly and the purge gas assembly are sequentially connected to the impurity removal assembly, the vacuum distillation assembly, the medium-pressure distillation assembly, and the high-pressure distillation assembly;

[0010] Preferably, the high-pressure reboiler assembly includes a first high-pressure tower reboiler and a first separator. A gas-to-gas heat exchanger is connected to the first high-pressure tower reboiler, the first high-pressure tower reboiler is connected to the first separator, the top of the first separator is connected to the medium-pressure reboiler assembly, the first high-pressure tower reboiler exchanges heat with the high-pressure distillation assembly, and the bottom of the first separator is connected to the hydraulic turbine assembly.

[0011] The medium-pressure reboiler assembly includes a first medium-pressure tower reboiler and a second separator. The first medium-pressure tower reboiler and the second separator are connected. The first medium-pressure tower reboiler exchanges heat with the medium-pressure distillation assembly. The first medium-pressure tower reboiler is connected to the first separator. The top of the second separator is connected to the vacuum reboiler assembly, and the bottom of the second separator is connected to the hydraulic turbine assembly.

[0012] The vacuum reboiler assembly includes a first vacuum tower reboiler and a third separator. The first vacuum tower reboiler and the third separator are connected. The first vacuum tower reboiler is connected to the second separator. The top of the third separator is connected to the water-cooled separation assembly. The first vacuum tower reboiler exchanges heat with the vacuum distillation assembly. The bottom of the third separator is connected to the hydraulic turbine assembly.

[0013] The water-cooled separation assembly includes a water cooler and a fourth separator. The water cooler and the fourth separator are connected. The water cooler is connected to the third separator. The top of the fourth separator is connected to the compressor. The bottom of the fourth separator is connected to the hydraulic turbine assembly. The top of the fourth separator is connected to the purge gas assembly.

[0014] Preferably, the purge gas assembly includes a purge gas scrubbing tower, with scrubbing water introduced into one side of the purge gas scrubbing tower, a water-cooled separation assembly connected to the bottom of the purge gas scrubbing tower, the bottom of the purge gas scrubbing tower connected to a decontamination assembly, and the bottom of the purge gas scrubbing tower connected to a hydraulic turbine assembly.

[0015] Furthermore, the impurity removal assembly includes a pre-tower, a hydraulic turbine assembly, and a purge gas assembly connected to one side of the pre-tower. The top of the pre-tower is equipped with a first condenser and a first cooling tank. The top of the pre-tower is sequentially connected to the first condenser and the first cooling tank. The bottom of the first cooling tank is connected to the upper part of the pre-tower. Non-condensable gas is discharged from one side of the first cooling tank.

[0016] The bottom of the pre-column is connected to the vacuum distillation unit, and the bottom of the pre-column is equipped with a first pre-column reboiler.

[0017] Furthermore, the vacuum distillation assembly includes a vacuum column and a second vacuum column reboiler;

[0018] The bottom of the impurity removal unit is connected to one side of the vacuum distillation tower, and the bottom of the vacuum distillation tower is connected to the medium-pressure distillation unit.

[0019] The vacuum distillation tower is connected to the reboiler of the second vacuum distillation tower; the reboiler of the second vacuum distillation tower is connected to the condenser of the medium-pressure distillation unit;

[0020] The top of the vacuum distillation tower is equipped with a second condenser and a second cooling tank. The bottom of the second cooling tank is connected to the top of the vacuum distillation tower, and the bottom of the second cooling tank outputs refined methanol.

[0021] The medium-pressure distillation unit includes a medium-pressure column and a second medium-pressure column reboiler;

[0022] The reduced pressure distillation unit is connected to one side of the medium-pressure column, and the bottom of the medium-pressure column is connected to the high-pressure distillation unit.

[0023] The medium-pressure column is connected to the second medium-pressure column reboiler, and the second medium-pressure column reboiler is connected to the condenser of the high-pressure distillation unit;

[0024] The top of the medium-pressure tower is equipped with a third condenser and a third cooling tank. The bottom of the third cooling tank is connected to the top of the medium-pressure tower, and the bottom of the third cooling tank outputs refined methanol.

[0025] Furthermore, the high-pressure distillation assembly includes a high-pressure column and a second high-pressure column reboiler;

[0026] The medium-pressure distillation unit is connected to one side of the high-pressure column.

[0027] Wastewater is discharged from the bottom of the high-pressure tower, and the high-pressure tower is connected to the reboiler of the second high-pressure tower;

[0028] The top of the high-pressure tower is connected to the fourth condenser and the fourth cooling tank. The bottom of the fourth cooling tank is connected to the top of the high-pressure tower, and the bottom of the fourth cooling tank outputs refined methanol.

[0029] Preferably, the high-pressure distillation unit is further connected in series with at least one other high-pressure distillation unit;

[0030] Preferably, the high-pressure distillation unit is further connected in series with another high-pressure distillation unit, and the bottom of the vacuum distillation tower is connected to a third vacuum distillation tower reboiler; the pre-tower is connected to a second pre-tower reboiler.

[0031] The fifth condenser of the high-pressure tower, located near the recovery tower, exchanges heat with the second pre-tower reboiler of the pre-tower.

[0032] The first condenser of the pre-decompression tower exchanges heat with the reboiler of the third decompression tower of the decompression tower.

[0033] Furthermore, one side of the high-pressure distillation unit is connected to the recovery unit;

[0034] The recovery assembly includes a recovery tower, with wastewater discharged from the bottom of the recovery tower. The bottom of the recovery tower is connected to the recovery tower reboiler, and the recovery tower reboiler is connected to the lower part of the recovery tower.

[0035] The top of the reboiler of the recovery tower is equipped with a sixth condenser and a sixth cooling tank. The bottom of the sixth cooling tank is connected to the top of the recovery tower, and fusel oil is output from the bottom of the sixth cooling tank.

[0036] Compared with existing technologies, the methanol production system of this utility model has the following advantages:

[0037] This application significantly reduces energy consumption in the methanol distillation process by coupling excess low-grade heat from the methanol synthesis process to the reboiler in the methanol distillation process. It also shortens the process flow, saves space, and reduces equipment investment. This overcomes the problems of long process routes and high energy consumption inherent in traditional methods, thereby improving economic efficiency. Attached Figure Description

[0038] The accompanying drawings, which form part of this utility model, are used to provide a further understanding of the utility model. The illustrative embodiments of the utility model and their descriptions are used to explain the utility model and do not constitute an undue limitation of the utility model. In the drawings:

[0039] Figure 1 This is a schematic diagram of a methanol production system according to Embodiment 1 of this utility model;

[0040] Figure 2 This is a schematic diagram of a methanol production system according to Embodiment 2 of this utility model.

[0041] Explanation of reference numerals in the attached figures:

[0042] 1. Methanol synthesis tower; 2. Compressor; 3. Gas-to-gas heat exchanger; 4. First high-pressure tower reboiler; 5. First separator; 6. First medium-pressure tower reboiler; 7. Second separator; 8. First vacuum tower reboiler; 9. Third separator; 10. Water cooler; 11. Fourth separator; 12. Purge gas scrubbing tower; 13. Hydraulic turbine assembly; 14. Pre-tower; 15. First pre-tower reboiler; 16. Second pre-tower reboiler; 17. Vacuum tower; 18. Fifth condenser; 19. Second depressurization tower reboiler; 20. Second condenser; 21. Second cooling tank; 22. Medium-pressure tower; 23. First condenser; 24. Second medium-pressure tower reboiler; 25. Third condenser; 26. Third cooling tank; 27. High-pressure tower; 28. Third depressurization tower reboiler; 29. ​​Second high-pressure tower reboiler; 30. Fourth condenser; 31. Fourth cooling tank; 32. Recovery tower; 33. Recovery tower reboiler; 34. Sixth condenser; 35. Sixth cooling tank. Detailed Implementation

[0043] It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.

[0044] In the description of this utility model, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this utility model, unless otherwise stated, "a plurality of" means two or more.

[0045] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0046] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0047] Example 1

[0048] A methanol production process includes the following steps: S1: The raw gas is pressurized and enters methanol synthesis tower 1. The outlet gas of methanol synthesis tower 1 is sequentially separated by gas-to-gas heat exchange, heat exchange by first high-pressure tower reboiler 4, heat exchange by medium-pressure tower reboiler 6, heat exchange by vacuum tower reboiler 8, and water cooling to obtain circulating gas and first liquid phase crude methanol.

[0049] The outlet gas from methanol synthesis tower 1 is sequentially separated by gas-to-gas heat exchange and then used in high-pressure tower 27, medium-pressure tower 22, and vacuum tower 17. After water cooling separation, it yields recycle gas and first-phase crude methanol. In step S2, a portion of the recycle gas is returned to step S1 and pressurized together with fresh gas, while the other portion is discharged as purge gas after washing to recover methanol. The first-phase crude methanol enters a hydraulic turbine unit to recover energy into second-phase crude methanol. In step S3, dissolved gases and low-boiling-point impurities in the second-phase crude methanol are removed by pre-distillation in pre-tower 14, followed by vacuum distillation, medium-pressure distillation, and high-pressure distillation to output refined methanol. Part of the recycle gas from step S2 is washed as purge gas to obtain recovered methanol. The recovered methanol and the second-phase crude methanol are mixed and then processed in step S3.

[0050] A methanol production system includes a compressor 2, a methanol synthesis tower 1, a gas-to-gas heat exchanger 3, a high-pressure reboiler assembly, a medium-pressure reboiler assembly, a vacuum reboiler assembly, a water-cooled separation assembly, a hydraulic turbine assembly 13, a purge gas assembly, a purification assembly, a vacuum distillation assembly, a medium-pressure distillation assembly, and at least one high-pressure distillation assembly; the compressor 2 is connected to the gas-to-gas heat exchanger 3, the gas-to-gas heat exchanger 3 is connected to the top of the methanol synthesis tower 1, and the bottom of the methanol synthesis tower 1 is connected to the gas-to-gas heat exchanger 3; the gas-to-gas heat exchanger 3, the high-pressure reboiler assembly, the medium-pressure reboiler assembly... The components, including the vacuum reboiler assembly, the water-cooled separation assembly, and the compressor 2, are connected in sequence. The gas-gas heat exchanger 3, the high-pressure reboiler assembly, the medium-pressure reboiler assembly, the vacuum reboiler assembly, and the water-cooled separation assembly, are connected to the hydraulic turbine assembly 13. The hydraulic turbine assembly 13 is connected to the purge gas assembly. The hydraulic turbine assembly 13 and the purge gas assembly are connected in sequence to the impurity removal assembly, the vacuum distillation assembly, the medium-pressure distillation assembly, and the high-pressure distillation assembly. The vacuum distillation assembly, the medium-pressure distillation assembly, and the high-pressure distillation assembly all output refined methanol.

[0051] The high-pressure reboiling assembly includes a first high-pressure tower reboiler 4 and a first separator 5. A gas-to-gas heat exchanger 3 is connected to the first high-pressure tower reboiler 4, which is connected to the first separator 5. The top of the first separator 5 is connected to the medium-pressure reboiling assembly, and the first high-pressure tower reboiler 4 is connected to the high-pressure distillation assembly. The bottom of the first separator 5 is connected to the hydraulic turbine assembly 13. The medium-pressure reboiling assembly includes a first medium-pressure tower reboiler 6 and a second separator 7. The medium-pressure tower reboiler 6 and the second separator 7 are connected. The first medium-pressure tower reboiler 6 is connected to the medium-pressure distillation assembly, and the first medium-pressure tower reboiler 6 is connected to the first separator 5. The top of the second separator 7 is connected to the reduced-pressure reboiling assembly, and the bottom of the second separator 7 is connected to the hydraulic turbine assembly. 13 is connected; the vacuum reboiler assembly includes a first vacuum tower reboiler 8 and a third separator 9, the first vacuum tower reboiler 8 and the third separator 9 are connected, the first vacuum tower reboiler 8 is connected to the second separator 7, the top of the third separator 9 is connected to the water-cooled separation assembly, the first vacuum tower reboiler 8 is connected to the vacuum distillation assembly, and the bottom of the third separator 9 is connected to the hydraulic turbine assembly 13; the water-cooled separation assembly includes a water cooler 10 and a fourth separator 11, the water cooler 10 and the fourth separator 11 are connected, the water cooler 10 is connected to the third separator 9, the top of the fourth separator 11 is connected to the compressor 2, the bottom of the fourth separator 11 is connected to the hydraulic turbine assembly 13, and the top of the fourth separator 11 is connected to the purge gas assembly;

[0052] The purge gas assembly includes a purge gas scrubbing tower 12, with scrubbing water introduced into one side of the purge gas scrubbing tower 12. A water-cooled separation assembly is connected to the bottom of the purge gas scrubbing tower 12, the bottom of the purge gas scrubbing tower 12 is connected to a cleansing assembly, and the bottom of the purge gas scrubbing tower 12 is connected to a hydraulic turbine assembly 13.

[0053] The impurity removal assembly includes a pre-tower 14, a hydraulic turbine assembly 13, and a purge gas assembly connected to one side of the pre-tower 14. The top of the pre-tower 14 is equipped with a first condenser 23 and a first cooling tank. The top of the pre-tower 14 is sequentially connected to the first condenser 23 and the first cooling tank. The bottom of the first cooling tank is connected to the upper part of the pre-tower 14, and non-condensable gas is discharged from one side of the first cooling tank. The bottom of the pre-tower 14 is connected to a vacuum distillation assembly and to a first pre-tower reboiler 15. The first pre-tower reboiler 15 is connected to the lower part of the pre-tower 14.

[0054] The vacuum distillation assembly includes a vacuum column 17 and a second vacuum column reboiler 19; the bottom of the impurity removal assembly is connected to one side of the vacuum column 17, and the bottom of the vacuum column 17 is connected to the medium-pressure distillation assembly; the bottom of the vacuum column 17 is connected to the second vacuum column reboiler 19, and the second vacuum column reboiler 19 is connected to the lower part of the vacuum column 17, and the second vacuum column reboiler 19 exchanges heat with the medium-pressure distillation assembly; the top of the vacuum column 17 is provided with a second condenser 20 and a second cooling tank 21, the bottom of the second cooling tank 21 is connected to the upper part of the vacuum column 17, and the bottom of the second cooling tank 21 outputs refined methanol;

[0055] The medium-pressure distillation unit includes a medium-pressure column 22, a second medium-pressure column reboiler 23, and a second medium-pressure column reboiler 24. The vacuum distillation unit is connected to one side of the medium-pressure column 22, the bottom of the medium-pressure column 22 is connected to the high-pressure distillation unit, the bottom of the medium-pressure column 22 is connected to the second medium-pressure column reboiler 23, the second medium-pressure column reboiler 23 exchanges heat with the medium-pressure reboiler unit, and the second medium-pressure column reboiler 23 is connected to the lower part of the medium-pressure column 22. The bottom of the medium-pressure column 22 is connected to the second medium-pressure column reboiler 24, the second medium-pressure column reboiler 24 exchanges heat with the high-pressure distillation unit, the top of the medium-pressure column 22 is equipped with a third condenser 25 and a third cooling tank 26, the bottom of the third cooling tank 26 is connected to the upper part of the medium-pressure column 22, and the bottom of the third cooling tank 26 outputs refined methanol.

[0056] The high-pressure distillation unit includes several high-pressure distillation components connected in sequence; the high-pressure distillation components include a high-pressure column 27 and a second high-pressure column reboiler 29; the medium-pressure distillation component is connected to one side of the high-pressure column 27, wastewater is discharged from the bottom of the high-pressure column 27, and the bottom of the high-pressure column 27 is connected to the second high-pressure column reboiler 29; the top of the high-pressure column 27 is connected to a fourth condenser 30 and a fourth cooling tank 31, the bottom of the fourth cooling tank 31 is connected to the upper part of the high-pressure column 27, and refined methanol is output from the bottom of the fourth cooling tank 31;

[0057] One side of the high-pressure distillation unit is connected to the recovery component; the recovery component includes a recovery tower 32, the bottom of which discharges wastewater, the bottom of which is connected to a recovery tower reboiler 33, and the recovery tower reboiler 33 is connected to the lower part of the recovery tower 32; the top of the recovery tower reboiler 33 is provided with a sixth condenser 34 and a sixth cooling tank 35, the bottom of which is connected to the upper part of the recovery tower 32, and the bottom of the sixth cooling tank 35 outputs fusel oil.

[0058] Methanol synthesis tower 1 pressure 50-90 bar

[0059] The operating pressure of pressure reducing tower 17 (or atmospheric tower) is 20–101 kPa (a).

[0060] The operating pressure of medium-pressure tower 22 is 100–380 kPa (a).

[0061] High-pressure tower 27 operates at a pressure of 380–900 kPa (a).

[0062] The syngas-side outlet temperature of the first high-pressure tower reboiler 4 is 105–120℃.

[0063] The syngas side outlet temperature of the reboiler 6 in the medium-pressure tower is 80–105℃.

[0064] The syngas-side outlet temperature of the first vacuum distillation tower reboiler 8 is 60–80℃.

[0065] The high-temperature heat of the synthesis process is matched with the high-temperature heat of the distillation process, the medium-temperature section is matched with the medium-temperature section of the distillation process, and the low-temperature heat is matched with the low-temperature section, with the heat transfer temperature difference controlled within 5–10℃.

[0066] Function descriptions of each device:

[0067] Gas compressor 2: Divided into a fresh section and a recirculation section. Fresh gas is pressurized to a certain pressure in the fresh section, and then combined with the recirculation section to reach the inlet pressure of the synthesis tower (50-90 barg is acceptable).

[0068] Methanol Synthesis Tower 1: Methanol is produced by reacting the synthesis gas (mainly H2, CO, CO2) from the fresh feed through a methanol synthesis catalyst.

[0069] Gas-to-gas heat exchanger 3: The heat from the gas exiting the synthesis tower is transferred to the synthesis gas through the gas-to-gas heat exchanger 3, thereby heating the synthesis gas to approximately 190–210°C.

[0070] The first high-pressure tower reboiler 4 cools the methanol in the outlet gas heat exchanger 3. This cooling process allows methanol to separate from the gas phase, while the heat of vaporization of the methanol is supplied to the high-pressure tower 27 for methanol distillation. This is the heat in the high-temperature zone; the outlet temperature of the high-pressure reboiler, on the synthesis gas side, can be controlled between 105℃ and 120℃.

[0071] First separator 5: Methanol exiting the first high-pressure tower reboiler 4 is separated through this separator.

[0072] The first medium-pressure reboiler 6 cools the methanol in the syngas phase exiting the first separator 5. This cooling process allows methanol to separate from the gas phase, while the heat of vaporization of the methanol is supplied to the medium-pressure column 22 for methanol distillation. This heat is generated in the medium-temperature zone; at the outlet of the medium-pressure reboiler, the syngas side temperature can be controlled between 80℃ and 105℃.

[0073] Second separator 7: Methanol from the first medium-pressure tower reboiler 6 is separated through this separator.

[0074] The first vacuum distillation tower reboiler 8 cools the methanol in the syngas phase exiting the second separator 7. This cooling process allows methanol to separate from the gas phase, while the heat of vaporization of the methanol is supplied to the vacuum distillation tower 17 for methanol rectification. This heat is generated in the low-temperature zone, and the syngas side temperature at the outlet of the medium-pressure reboiler can be controlled between 60℃ and 80℃.

[0075] Third separator 9: Methanol from the first vacuum distillation tower reboiler 8 is separated through this separator.

[0076] Water cooler 10: The unusable low-temperature heat is cooled by water cooler 10, thereby achieving full separation of methanol, reducing the methanol content in the returned synthesis gas, and thus improving the conversion rate of the reaction.

[0077] Fourth separator 11: Methanol from water cooler 10 is separated through this separator.

[0078] Purge gas scrubbing tower 12: In order to reduce the methanol content in the purge gas, water is sprayed from the top of the purge gas scrubbing tower 12 to scrub the purge gas, thereby washing the methanol into the scrubbing water.

[0079] Hydraulic turbine unit: The methanol outlets from gas-to-gas heat exchanger 3, first separator 5, second separator 7, third separator 9, and fourth separator 11 are combined and sent to the hydraulic turbine unit to recover the energy. The energy from the high-pressure to low-pressure methanol recovery process can be converted into electrical energy or used to drive pumps. At night, the turbine unit's inlet pressure is 50-80 barg, and the outlet pressure is 3-5 barg.

[0080] Pre-tower 14: Removes dissolved gas from methanol. The operating pressure is atmospheric pressure to 1 barg. The dissolved gas and low-boiling-point components are removed by heating through a reboiler.

[0081] Reduced pressure distillation column 17: Methanol is extracted through reduced pressure distillation. Its operating pressure is 20–101 kPa(a). Its heat source is twofold: methanol vapor from the top of the medium-pressure column 22 and the low-temperature section of the syngas. Through the combined heat from the syngas and the vapor at the top of the medium-pressure column 22, refined methanol with a concentration of not less than 99.85% wt is extracted. Refined methanol is extracted from the top of the column, while methanol-water is extracted from the bottom.

[0082] Medium-pressure distillation column 22: Methanol is extracted through medium-pressure distillation, operating at a pressure of 100–380 kPa(a). Its heat source consists of two parts: methanol vapor from the top of high-pressure column 27 and the intermediate-temperature section of the syngas. Through the combined heat from the syngas and the vapor at the top of high-pressure column 27, refined methanol with a concentration of not less than 99.85% wt is extracted. Refined methanol is extracted from the top of the column, while methanol-water is extracted from the bottom.

[0083] High-pressure distillation column 27: Methanol is extracted through high-pressure distillation, operating at a pressure of 100–380 kPa(a). Its heat source consists of two parts: medium-pressure steam and a high-temperature section of syngas. By combining the heat from the syngas and medium-pressure steam, refined methanol with a concentration of not less than 99.85% wt is extracted. Refined methanol is extracted from the top of column 27, fusel oil water is extracted from the middle section, and wastewater is extracted from the bottom.

[0084] Recovery Tower 32: Fusel from high-pressure tower 27 enters recovery tower 32 for fusel oil recovery. The operating pressure of this tower is 100-150 kPa(a). Fusel is collected at the top of the tower, and wastewater is collected at the bottom.

[0085] After compression and synthesis, the fresh gas produces methanol, which is then distilled through vacuum distillation tower 17, medium-pressure tower 22, and high-pressure tower 27 to obtain refined methanol with a purity of not less than 99.85%, meeting the US Federal AA grade (OM-232E) quality standards. Wastewater is collected from the bottom of high-pressure tower 27 and recovery tower 32 and then discharged from the unit. Purge gas exits the unit through purge gas scrubbing tower 12. Non-condensable gases dissolved in methanol are discharged after distillation in pre-distillation tower 14.

[0086] This embodiment adopts a five-tower, three-effect distillation process. Based on the different low-temperature heat of methanol synthesis tower 1, heat coupling is performed with the reboiler of methanol distillation tower. The distillation process adopts a heat coupling process, which transfers the heat from the high-pressure condenser to the medium-pressure tower 22, and the heat from the condenser of the medium-pressure tower 22 to the low-pressure tower.

[0087] This embodiment takes the countercurrent five-tower triple-effect process as an example.

[0088] Fresh gas and recirculated gas are pressurized by recirculated gas compressor 2 and then enter the synthesis tower. The gas exiting the synthesis tower is cooled by gas-to-gas heat exchanger 3 and then enters the first high-pressure tower reboiler 4. While cooling, it provides heat for the distillation of high-pressure tower 27. The methanol exiting the first high-pressure tower reboiler 4 is separated into crude methanol by a separator. The gas phase enters the medium-pressure tower reboiler 6 for further cooling and separation of crude methanol. The gas phase enters the vacuum tower reboiler 8. After the synthesis gas has fully utilized its low-temperature heat, it enters the water cooler 10 for cooling. After cooling, all the separated methanol is combined and sent to the hydraulic turbine unit to recover energy. The gas phase is returned to the recirculated gas compressor 2 unit. The system purge gas enters the purge gas scrubbing tower 12, where a small amount of methanol is recovered through water washing.

[0089] Wash water and crude methanol (methanol and second liquid-phase crude methanol) directly enter the pre-distillation column 14 in the rectification sequence. Pre-distillation column 14 removes dissolved gases and low-boiling-point impurities from the methanol. Then, it enters the vacuum distillation column 17 for rectification. The heat source for vacuum distillation column 17 is twofold: the lower heating value of the methanol synthesis gas and the condensation heat from the top vapor phase of the medium-pressure column 22. Unseparated methanol-water further enters the medium-pressure column 22. The heat source for medium-pressure column 22 is partly from the lower heating value of the methanol synthesis gas and partly from the condensation heat from the top vapor phase of the high-pressure column 27. The remaining methanol after separation of refined methanol enters the high-pressure column 27. Refined methanol is collected at the top of the high-pressure column 27, fusel oils are collected in the middle, and pure water is separated at the bottom. The heat source for high-pressure column 27 is twofold: the lower heating value of the synthesis gas and medium-pressure steam.

[0090] The fusel oil collected from high-pressure tower 27 enters recovery tower 32. The top of recovery tower 32 yields fusel oil, while the bottom yields wastewater.

[0091] Example 2

[0092] The difference from Example 1 is that: the number of high-pressure distillation components is 2; the bottom of the vacuum distillation tower 17 is provided with a third vacuum distillation tower reboiler 28; the third vacuum distillation tower reboiler 28 is connected to the lower part of the vacuum distillation tower 17; the bottom of the pre-tower 14 is provided with a second pre-tower reboiler 16; the second pre-tower reboiler 16 is connected to the lower part of the pre-tower 14; the fifth condenser 18 of the high-pressure tower near the recovery tower 32 exchanges heat with the second pre-tower reboiler 16 of the pre-tower 14; the first condenser 23 of the pre-tower 14 exchanges heat with the third vacuum distillation tower reboiler 28 of the vacuum distillation tower 17.

[0093] Figure 2 Process Comparison Figure 1 The process is characterized by the fact that, for energy conservation reasons, the 6-tower 4-effect process is more energy-efficient than the 5-tower 3-effect process, but the initial investment in equipment is higher. This will be adjusted according to actual conditions. Figure 1 process or Figure 2 Choose the process.

[0094] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A system for the production of methanol, characterized by: It includes compressors, methanol synthesis towers, gas-to-gas heat exchangers, high-pressure reboiler components, medium-pressure reboiler components, vacuum reboiler components, water-cooled separation components, hydraulic turbine components, purge gas components, impurity removal components, vacuum distillation components, medium-pressure distillation components, and high-pressure distillation components; The compressor is connected to the gas-to-gas heat exchanger, the gas-to-gas heat exchanger is connected to the top of the methanol synthesis tower, and the bottom of the methanol synthesis tower is connected to the gas-to-gas heat exchanger. The gas-to-gas heat exchanger, high-pressure reboiler assembly, medium-pressure reboiler assembly, low-pressure reboiler assembly, and water-cooled separation assembly are connected in sequence, and the water-cooled separation assembly is connected to the compressor. The gas-to-gas heat exchanger, high-pressure reboiler assembly, medium-pressure reboiler assembly, vacuum reboiler assembly, and water-cooled separation assembly are all connected to the hydraulic turbine assembly. The vacuum distillation assembly, medium-pressure distillation assembly, and high-pressure distillation assembly all output refined methanol.

2. A system for the production of methanol according to claim 1, characterized in that: The hydraulic turbine assembly is connected to the purge gas assembly; the hydraulic turbine assembly and the purge gas assembly are connected in sequence to the impurity removal assembly, the vacuum distillation assembly, the medium-pressure distillation assembly, and the high-pressure distillation assembly.

3. The system for producing methanol according to claim 1, wherein: The high-pressure reboiler assembly includes a first high-pressure tower reboiler and a first separator. A gas-gas heat exchanger is connected to the first high-pressure tower reboiler. The first high-pressure tower reboiler is connected to the first separator. The top of the first separator is connected to the medium-pressure reboiler assembly. The first high-pressure tower reboiler exchanges heat with the high-pressure distillation assembly. The bottom of the first separator is connected to the hydraulic turbine assembly. The medium-pressure reboiler assembly includes a first medium-pressure tower reboiler and a second separator. The first medium-pressure tower reboiler and the second separator are connected. The first medium-pressure tower reboiler exchanges heat with the medium-pressure distillation assembly. The first medium-pressure tower reboiler is connected to the first separator. The top of the second separator is connected to the vacuum reboiler assembly, and the bottom of the second separator is connected to the hydraulic turbine assembly. The vacuum reboiler assembly includes a first vacuum tower reboiler and a third separator. The first vacuum tower reboiler and the third separator are connected. The first vacuum tower reboiler is connected to a second separator. The top of the third separator is connected to a water-cooled separation assembly. The first vacuum tower reboiler exchanges heat with the bottom of the vacuum distillation assembly. The bottom of the third separator is connected to a hydraulic turbine assembly. The water-cooled separation assembly includes a water cooler and a fourth separator. The water cooler and the fourth separator are connected. The water cooler is connected to the third separator. The top of the fourth separator is connected to the compressor. The bottom of the fourth separator is connected to the hydraulic turbine assembly. The top of the fourth separator is connected to the purge gas assembly.

4. The system for producing methanol according to claim 1, wherein: The purge gas assembly includes a purge gas scrubbing tower, with scrubbing water introduced into one side of the purge gas scrubbing tower. A water-cooled separation assembly is connected to the bottom of the purge gas scrubbing tower, the bottom of the purge gas scrubbing tower is connected to a cleanup assembly, and the bottom of the purge gas scrubbing tower is connected to a hydraulic turbine assembly.

5. A methanol production system according to claim 1, characterized in that: The impurity removal assembly includes a pre-tower, a hydraulic turbine assembly, and a purge gas assembly connected to one side of the pre-tower. The top of the pre-tower is equipped with a first condenser and a first cooling tank. The top of the pre-tower is connected to the first condenser and the first cooling tank in sequence. The bottom of the first cooling tank is connected to the upper part of the pre-tower. Non-condensable gas is discharged from one side of the first cooling tank. The bottom of the pre-column is connected to the vacuum distillation unit, and the bottom of the pre-column is equipped with a first pre-column reboiler.

6. The system for producing methanol according to claim 1, wherein: The vacuum distillation unit includes a vacuum column and a second vacuum column reboiler; The bottom of the impurity removal component is connected to one side of the vacuum distillation tower, and the bottom of the vacuum distillation tower is connected to the medium-pressure distillation component; the vacuum distillation tower is connected to the reboiler of the second vacuum distillation tower; the reboiler of the second vacuum distillation tower is connected to the condenser of the medium-pressure distillation component. The top of the vacuum distillation tower is equipped with a second condenser and a second cooling tank. The bottom of the second cooling tank is connected to the top of the vacuum distillation tower, and the bottom of the second cooling tank outputs refined methanol. The medium-pressure distillation unit includes a medium-pressure column and a second medium-pressure column reboiler; The reduced pressure distillation unit is connected to one side of the medium-pressure column, and the bottom of the medium-pressure column is connected to the high-pressure distillation unit. The medium-pressure column is connected to the second medium-pressure column reboiler, and the second medium-pressure column reboiler is connected to the condenser of the high-pressure distillation unit; The top of the medium-pressure tower is equipped with a third condenser and a third cooling tank. The bottom of the third cooling tank is connected to the top of the medium-pressure tower, and the bottom of the third cooling tank outputs refined methanol.

7. A methanol production system according to claim 1, characterized in that: The high-pressure distillation unit includes a high-pressure column and a second high-pressure column reboiler; The medium-pressure distillation unit is connected to one side of the high-pressure column. Wastewater is discharged from the bottom of the high-pressure tower, and the high-pressure tower is connected to the reboiler of the second high-pressure tower; The top of the high-pressure tower is connected to the fourth condenser and the fourth cooling tank. The bottom of the fourth cooling tank is connected to the top of the high-pressure tower, and the bottom of the fourth cooling tank outputs refined methanol.

8. The system for producing methanol according to claim 1, wherein: The high-pressure distillation unit is also connected in series with at least one other high-pressure distillation unit.

9. The system for producing methanol according to claim 1, wherein: The high-pressure distillation unit is also connected in series with another high-pressure distillation unit, and the bottom of the vacuum distillation tower is connected to a third vacuum distillation tower reboiler; the pre-tower is connected to a second pre-tower reboiler. The fifth condenser of the high-pressure tower, located near the recovery tower, exchanges heat with the second pre-tower reboiler of the pre-tower. The first condenser of the pre-decompression tower exchanges heat with the reboiler of the third decompression tower of the decompression tower.

10. The system for producing methanol according to claim 1, wherein: One side of the high-pressure distillation unit is connected to the recovery unit; The recovery assembly includes a recovery tower, with wastewater discharged from the bottom of the recovery tower. The bottom of the recovery tower is connected to the recovery tower reboiler, and the recovery tower reboiler is connected to the lower part of the recovery tower. The top of the reboiler of the recovery tower is equipped with a sixth condenser and a sixth cooling tank. The bottom of the sixth cooling tank is connected to the top of the recovery tower, and fusel oil is output from the bottom of the sixth cooling tank.

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