Energy-saving system and process for coupling methanol-eluted carbon flash vapor and concentrated gas for soda ash production

Abstract

The present invention discloses an energy-saving system and process for coupling methanol-eluted carbon flash vapor and concentrated gas to produce soda ash, belonging to the field of synthetic ammonia combined soda process. The system includes a washing tower provided with a lower desulfurization section and an upper decarbonization section, a first flash tank with a liquid phase inlet connected to the liquid phase outlet of the upper decarbonization section, a second flash tank with a liquid phase inlet connected to the liquid phase outlet of the lower desulfurization section, a desulfurization tower, a carbonization tower with a gas phase inlet connected to the gas phase outlet of the first flash tank and the gas phase outlet of the desulfurization tower, a purification tower with a gas phase outlet connected to the gas phase inlet of the lower desulfurization section through a booster, a low-pressure regeneration system with an inlet connected to the liquid phase outlets of the second flash tank and the desulfurization tower, and auxiliary equipment, etc.; the liquid phase inlet of the desulfurization tower is connected to the liquid phase outlet of the first flash tank, and the gas phase inlet is connected to the gas phase outlet of the second flash tank. The present invention eliminates the CO2 compressor in the traditional combined concentrated gas soda ash production system, and also reduces the power consumption of the flash vapor booster by 70-90%, reducing the operating power consumption of the system.

Description

Technical Field

[0001] The present invention relates to the technical field of synthetic ammonia combined soda technology, in particular to an energy-saving system and process for coupling the production of soda ash by combining the methanol-eluted carbon flash vapor and concentrated gas. Background Art

[0002] The synthetic ammonia combined soda process using concentrated gas CO 2 usually uses the low-pressure pure CO produced in the decarbonization section of the synthetic ammonia system. 2 CO 2 is pressurized by a compressor to 0.3 - 0.6 MPa required for soda production and reacts with ammoniacal brine in a carbonation tower to produce NaHCO 3 NaHCO 3 is then calcined to obtain the product Na 2 CO 3 . During the synthetic ammonia production process, in order to avoid the loss of H 2 and CO in the raw material gas during the decarbonization process of the synthetic ammonia system, the CO 2 rich solution generally undergoes pressure flash evaporation to flash off H 2 and CO with relatively low solubility in the decarbonization solution in advance, and they are recycled for reuse. However, a large amount of CO 2 is flashed off during the flash evaporation process. The CO 2 content in the flash vapor is as high as 70 - 90%, resulting in a substantial increase in the power consumption of the flash vapor recycle compressor. And due to the recycle of CO 2 , the operating load of the decarbonization tower is also increased.

[0003] The specific process of the traditional concentrated gas combined soda system is as Figure 2 shown:

[0004] The shift gas enters the lower desulfurization section of the scrubber 1 and is scrubbed with rich CO 2 methanol from the upper decarbonization section to completely remove H 2 S in the gas. Then the gas enters the upper decarbonization section and is scrubbed with lean decarbonization methanol to remove CO 2 to meet the purification requirements. The purified gas coming out from the top of the scrubber 1 goes to the subsequent section;

[0005] The methanol-rich liquid without H 2 S and the methanol-rich liquid containing H 2 S in the upper decarbonization section and the lower desulfurization section of the scrubber 1 respectively enter the first flash tank 2 and the second flash tank 3. The flashed gas containing H 2 and CO is combined and sent to the booster 11 for pressurization and then recycled to the scrubber 1 for reuse. The flashed methanol-rich liquid goes to the low-pressure regeneration system 8 respectively. The liquid containing H 2 S and CO 2In the acid gas desulfurization and recovery section, the regenerated lean methanol solution coming out of the low-pressure regeneration system 8 is sent to the decarbonization section at the upper part of the scrubbing tower 1 after passing through the circulation pump 9. The low-pressure CO 2 A part is sent to the carbonation tower 5 after being pressurized by the compressor 10, and the excess part is sent to users such as the urea section and the coal conveying section or is vented. The low-pressure CO 2 Reacts with ammoniacal brine in the carbonation tower 5 to produce sodium bicarbonate and ammonium chloride. After the materials at the lower part of the carbonation tower are processed by the centrifuge 7, the solid product sodium bicarbonate is sent to the calcination section, and the mother liquor is recycled after ammonia absorption and salt dissolution to separate ammonium chloride. The tail gas at the top of the carbonation tower 5 is sent to the purification tower 6. After being washed with washing water in the purification tower 6, the tail gas is directly vented, and the washing liquid at the bottom is sent to the salt dissolution or ammonia absorption section. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide an energy-saving system and process for coupling the flash steam of methanol elution decarbonization and the concentrated gas in soda ash production, making full use of the pressure of the flash steam, and combining the requirements of the combined soda ash production system for the CO 2 gas volume, appropriately controlling the flash pressure so that the CO 2 gas volume in the flash steam meets the requirements of soda ash production.

[0007] To solve the above technical problems, the technical solution adopted by the present invention is as follows:

[0008] An energy-saving system for coupling the flash steam of methanol elution decarbonization and the concentrated gas in soda ash production, comprising a scrubbing tower, a first flash tank, a second flash tank, a carbonation tower, a purification tower, a low-pressure regeneration system, a centrifuge, a circulation pump and each connecting pipeline; the scrubbing tower includes a lower desulfurization section and an upper decarbonization section; the liquid phase inlet of the first flash tank is connected to the liquid phase outlet of the upper decarbonization section; the liquid phase inlet of the second flash tank is connected to the liquid phase outlet of the lower desulfurization section, and the system also includes a desulfurization tower; the liquid phase inlet of the desulfurization tower is connected to the bottom liquid phase outlet of the first flash tank, and the gas phase inlet of the desulfurization tower is connected to the upper gas phase outlet of the second flash tank; the upper gas phase outlet of the first flash tank and the upper gas phase outlet of the desulfurization tower are both connected to the gas phase inlet of the carbonation tower; the bottom liquid phase outlet of the second flash tank and the bottom liquid phase outlet of the desulfurization tower are both connected to the inlet of the low-pressure regeneration system; the regenerated lean methanol solution of the low-pressure regeneration system is connected to the liquid phase inlet of the upper decarbonization section of the scrubbing tower through a circulation pump, and the regenerated CO 2 gas is connected to users or vented; the H 2 S and CO 2 acid gas outlet of the low-pressure regeneration system is connected to the sulfur recovery section; the top gas phase outlet of the purification tower is connected to the gas phase inlet of the lower desulfurization section of the scrubbing tower; a booster is provided on the pipeline connecting the top gas phase outlet of the purification tower and the gas phase inlet of the lower desulfurization section of the scrubbing tower.

[0009] A further improvement of the technical solution of the present invention lies in that valves for adjusting the material flow rate in the pipeline according to the liquid level of the equipment are provided at the bottom liquid phase outlet ends of the lower desulfurization section, the upper decarbonization section, the first flash tank, the second flash tank, the desulfurization tower, and the purification tower.

[0010] A further improvement of the technical solution of the present invention lies in that a centrifuge capable of performing solid-liquid separation is provided at the bottom material outlet end of the carbonation tower, and a valve for adjusting the material flow rate in the pipeline according to the liquid level of the equipment is also provided at the bottom material outlet end of the carbonation tower.

[0011] An energy-saving process for coupling methanol elution decarbonization flash gas and thick gas to produce soda ash is as follows:

[0012] The shift gas enters the lower desulfurization section of the washing tower and is washed with methanol from the upper decarbonization section to completely remove H 2 S in the shift gas. Then the gas enters the upper decarbonization section and is washed with lean decarbonized methanol to remove CO 2 until the purification requirements of the shift gas are met. The purified gas coming out from the top of the washing tower goes to the subsequent process section; 2 The methanol-rich liquid without H

[0013] S coming out from the upper decarbonization section of the washing tower enters the first flash tank; the methanol-rich liquid containing H 2 S coming out from the lower desulfurization section of the washing tower enters the second flash tank. The first flash gas containing H 2 coming out from the upper gas phase outlet of the first flash tank goes to the carbonation tower; the second flash gas containing H 2 、CO、CO 2 coming out from the upper gas phase outlet of the second flash tank goes to the desulfurization tower. The methanol-rich liquid without H 2 、CO、CO 2、 H 2 S coming out from the bottom liquid phase outlet of the first flash tank is washed and desulfurized in the desulfurization tower, and then the gas goes to the carbonation tower. In the carbonation tower, the first flash gas from the upper gas phase outlet of the first flash tank and the desulfurized gas from the upper gas phase outlet of the desulfurization tower react with ammoniated brine to produce ammonium chloride and sodium bicarbonate. The lower material coming out from the bottom material outlet of the carbonation tower is processed by a centrifuge, and the solid product sodium bicarbonate goes to the calcination section. The mother liquor is recycled after ammonia absorption, salt dissolution, and ammonium chloride separation; the tail gas coming out from the top gas phase outlet of the carbonation tower goes to the purification tower. The tail gas is washed with washing water in the purification tower and then pressurized by a booster and recycled to the washing tower for reuse. The washing liquid coming out from the bottom liquid phase outlet of the purification tower goes to the salt dissolution or ammonia absorption section; 2 The methanol-rich liquid containing H

[0014] S coming out from the bottom liquid phase outlet of the second flash tank and the washing liquid coming out from the bottom liquid phase outlet of the desulfurization tower both return to the low-pressure regeneration system. After being processed by the low-pressure regeneration system, the H 2 -containing methanol-rich liquid and the washing liquid are both recycled to the low-pressure regeneration system. After being processed by the low-pressure regeneration system, the H2 S and CO 2 in the acid gas desulfurization and recovery section, the lean liquid after being treated by the low-pressure regeneration system goes to the upper decarbonization section of the scrubbing tower after passing through the circulation pump, and the low-pressure CO 2 goes to the user or is vented.

[0015] A further improvement of the technical solution of the present invention lies in that: the pressures of the first flash tank, the second flash tank and the desulfurization tower are all set to 0.5 - 2.0 Mpa according to the requirement of the combined soda process for the amount of CO 2

[0016] Due to the adoption of the above technical solution, the technical progress obtained by the present invention is as follows:

[0017] 1. By adjusting the pressures of the first flash tank and the second flash tank, and arranging a desulfurization tower behind the second flash tank, the present invention uses the methanol-rich liquid without H 2 S coming out of the first flash tank to desulfurize the flash gas coming out of the second flash tank. After the first flash gas and the desulfurized second flash gas are combined, they enter the carbonization tower to react with the ammoniated brine. The tail gas containing H 2 , CO coming out of the purification tower is returned to the scrubbing tower through a booster for recycling, so that the entire system does not need to be provided with a CO 2 compressor in the traditional combined concentrated gas soda-making system, saving the one-time investment and reducing the power consumption of the system.

[0018] 2. The present invention uses the CO 2 in the first and second flash gases as the raw material of the soda-making system, and the unreacted H 2 , CO are returned to the scrubbing tower through a booster for recycling, reducing the power consumption of the methanol scrubbing desulfurization and decarbonization flash gas circulation booster in the synthetic ammonia system by 70 - 90%, and greatly saving the investment and operating power consumption of the flash gas circulation booster.

[0019] 3. There are a small amount of non-reactive gases such as H 2 , CO in the flash gas used as the carbonization raw material gas in the present invention, which can increase the agitation effect of the gas on the liquid in the carbonization tower of the combined soda system, increase the gas-liquid contact opportunity, improve the mass transfer efficiency, and reduce the probability of scaling in the carbonization tower. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts;

[0021] Figure 1 ​It is a schematic diagram of an energy-saving system and process for coupling methanol-eluted carbon flash vapor and concentrated gas to produce soda ash provided by an embodiment of the present invention;

[0022] Figure 2 It is a schematic diagram of a traditional combined concentrated gas soda ash production system and process in the background art of the present invention;

[0023] Among them, 1. Scrubbing tower; 2. First flash tank; 3. Second flash tank; 4. Desulfurization tower; 5. Carbonation tower; 6. Purification tower; 7. Centrifuge; 8. Low-pressure regeneration system; 9. Circulation pump; 10. Compressor; 11. Booster. Detailed implementation manners

[0024] It should be noted that the terms "including" and "having" and any variations thereof in the description and claims of the present invention and the above-mentioned drawings are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device including a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0025] By providing an energy-saving system and process for coupling methanol-eluted carbon flash vapor and concentrated gas to produce soda ash in the embodiments of the present application, the problem existing in the prior art that "during the flash evaporation process, a large amount of CO 2 is flashed, and the CO 2 content in the flash vapor is as high as 70-90%, resulting in a substantial increase in the power consumption of the flash vapor circulation compressor, and due to the circulation of CO 2 also increasing the operating load of the decarbonization tower." is solved. The general idea is as follows: A desulfurization tower is arranged between the first flash tank and the second flash tank and before the low-pressure regeneration system, the pressures of the first flash tank, the second flash tank and the desulfurization tower are adjusted so that the amount of flash vapor meets the requirements for soda ash production and the flash vapor is directly sent into the carbonation tower for reaction, the compressor after the low-pressure regeneration system is cancelled, and the tail gas coming out of the purification tower is returned to the scrubbing tower through a booster for recycling.

[0026] The present invention will be further described in detail below with reference to the drawings and embodiments:

[0027] As Figure 1As shown in the figure, this embodiment provides an energy-saving system for coupling methanol-eluted carbon flash vapor and concentrated gas to produce soda ash, which includes a washing tower 1, a first flash tank 2, a second flash tank 3, a carbonization tower 5, a purification tower 6, a low-pressure regeneration system 8, a centrifuge 7, a circulation pump 9 and various connecting pipelines; the washing tower 1 includes a lower desulfurization section and an upper decarbonization section; the liquid phase inlet of the first flash tank 2 is connected to the liquid phase outlet of the upper decarbonization section; the liquid phase inlet of the second flash tank 3 is connected to the liquid phase outlet of the lower desulfurization section, and the system also includes a desulfurization tower 4; the liquid phase inlet of the desulfurization tower 4 is connected to the bottom liquid phase outlet of the first flash tank 2, and the gas phase inlet of the desulfurization tower 4 is connected to the upper gas phase outlet of the second flash tank 3; the upper gas phase outlet of the first flash tank 2 and the upper gas phase outlet of the desulfurization tower 4 are both connected to the gas phase inlet of the carbonization tower 5; the bottom liquid phase outlet of the second flash tank 3 and the bottom liquid phase outlet of the desulfurization tower 4 are both connected to the inlet of the low-pressure regeneration system 8; the lean liquid outlet of the low-pressure regeneration system 8 is connected to the upper decarbonization section liquid phase inlet of the washing tower 1 through the circulation pump 9, and the low-pressure CO 2 outlet is connected to the user or vented; the acidic gas outlet containing H 2 S and CO 2 of the low-pressure regeneration system 8 is connected to the sulfur recovery section; the top gas phase outlet of the purification tower 6 is connected to the gas phase inlet of the lower desulfurization section of the washing tower 1; a booster 11 is provided on the pipeline connecting the top gas phase outlet of the purification tower 6 and the gas phase inlet of the lower desulfurization section of the washing tower 1.

[0028] Furthermore, valves for adjusting the material flow in the pipeline according to the liquid level of the equipment are provided at the bottom liquid phase outlet ends of the lower desulfurization section, the upper decarbonization section, the first flash tank 2, the second flash tank 3, the desulfurization tower 4 and the purification tower 6. The setting of each valve further ensures the safety and stability of the system.

[0029] Furthermore, a centrifuge 7 capable of performing solid-liquid separation is provided at the bottom material outlet end of the carbonization tower 5, and a valve for adjusting the material flow in the pipeline according to the liquid level of the equipment is also provided at the bottom material outlet end of the carbonization tower 5.

[0030] An energy-saving process for coupling methanol-eluted carbon flash vapor and concentrated gas to produce soda ash is as follows:

[0031] The shift gas enters the lower desulfurization section of the washing tower 1 and is washed with the rich CO 2 methanol coming from the upper decarbonization section to completely remove H 2 S in the shift gas. Then the gas enters the upper decarbonization section and is washed with the lean decarbonized methanol to remove CO 2 until it meets the purification requirements of the shift gas. The purified gas coming out from the top of the washing tower 1 goes to the subsequent section;

[0032] The H-free methanol-rich solution coming out from the upper decarbonization section of the scrubbing tower 1 2 enters the first flash tank 2; the H-containing methanol-rich solution coming out from the lower desulfurization section of the scrubbing tower 1 2 enters the second flash tank 3. The first flash gas containing H 2 and CO coming out from the upper gas phase outlet of the first flash tank 2 goes to the carbonation tower 5; the second flash gas containing H 2 and CO and H 2 S coming out from the upper gas phase outlet of the second flash tank 3 goes to the desulfurization tower 4. The H-free methanol-rich solution coming out from the bottom liquid phase outlet of the first flash tank 2 2 is washed and desulfurized in the desulfurization tower 4, and then the gas goes to the carbonation tower 5. In the carbonation tower 5, the first flash gas from the upper gas phase outlet of the first flash tank 2 and the desulfurized gas from the upper gas phase outlet of the desulfurization tower 4 react with the ammoniated brine to generate ammonium chloride and sodium bicarbonate. The lower material coming out from the bottom material outlet of the carbonation tower 5 is processed in the centrifuge 7, and the solid product sodium bicarbonate goes to the calcination section, and the mother liquor is recycled after ammonia absorption, salt dissolution, and ammonium chloride separation; the tail gas coming out from the top gas phase outlet of the carbonation tower 5 goes to the purification tower 6. The tail gas is washed with washing water in the purification tower 6 and then pressurized by the booster 11 and recycled to the scrubbing tower 1 for reuse. The washing liquid coming out from the bottom liquid phase outlet of the purification tower 6 goes to the salt dissolution or ammonia absorption section;

[0033] The H-containing methanol-rich solution coming out from the bottom liquid phase outlet of the second flash tank 3 2 and the washing liquid coming out from the bottom liquid phase outlet of the desulfurization tower 4 both return to the low-pressure regeneration system 8. The acidic gas containing H 2 S and CO 2 after being processed by the low-pressure regeneration system 8 goes to the sulfur recovery section. The lean solution after being processed by the low-pressure regeneration system 8 goes to the upper decarbonization section of the scrubbing tower 1 after passing through the circulation pump 9, and the low-pressure CO 2 goes to the user or is vented.

[0034] Furthermore, the pressures of the first flash tank 2, the second flash tank 3, and the desulfurization tower 4 are set to 0.5 - 2.0 Mpa according to the requirement of the combined soda for the CO 2 quantity.

[0035] Working principle:

[0036] As Figure 2 shown, the job tasks of the upper decarbonization section and the lower desulfurization section (methanol scrubbing section) of the scrubbing tower 1 are to remove impurities such as CO 2 (for urea production or soda making, etc.) and H 2 S from the shifted gas. The composition content (volume fraction) of the shifted gas (pressure 3.2 - 5.8 MPa): CO 2 is 45%, H 2 S is 0.22%, CO is 0.4%, H 2is 54%. During the physical absorption process of lean methanol solution, part of the H 2 and CO are dissolved into the methanol solution together. To recover this part of the effective gas for ammonia synthesis, the method of pressure flash evaporation is adopted to desorb and separate H 2 and CO from the methanol solution (the functions of the first flash tank 2 and the second flash tank 3). However, during the flash evaporation process, a large amount of CO 2 is desorbed at the same time, accounting for 70 - 90% of the flash gas volume fraction, and the pressure of the flash gas is generally 0.9 - 1.6 MPa. Therefore, a booster 11 is needed to boost the pressure to about 3.2 - 5.8 MPa for reuse in the system. The pressure of CO 2 coming out of the low-pressure regeneration system 8 is 0.12 Mpa, and a compressor 10 is required to adjust the pressure to adapt to the pressure of 0.3 - 0.6 Mpa in the carbonization tower 5.

[0037] As Figure 1 shown, according to the CO 2 quantity required by the double soda process section, the pressures of the first flash tank 2 and the second flash tank 3 are adjusted to 0.6 - 1.6 Mpa (originally 0.9 - 1.6 Mpa), so that the flash gas coming out not only meets the requirement of the double soda for the CO 2 quantity, but also the pressure can be adjusted to 0.3 - 0.6 Mpa to match the 0.3 - 0.6 Mpa required for soda making. The flash gas containing CO 2 and H 2 and CO is directly sent to carbonization for soda making. All the CO 2 reacts in the carbonization tower 5 to finally produce the product sodium carbonate. The effective gas for ammonia synthesis, H 2 and CO, in the tail gas of the carbonization tower 5 is washed and purified, and then boosted to about 3.2 - 5.8 MPa by the booster 11 and returned to the system for reuse. Therefore, compared with the traditional process as Figure 2 shown, the load of the booster 11 is reduced by 70 - 90%. Since H 2 S is released from the second flash tank 3, a desulfurization tower 4 is added to further desulfurize.

[0038] After calculation: for the system as Figure 2 shown, calculated based on an ammonia synthesis plant with an annual output of 600,000 tons in the enterprise, the power of the recycling booster 11 is 630 kw. Calculated according to 330 days of production in a year, 630×24×330 = 4,989,600 kWh. It can be seen that the technical solution provided by the present invention saves 70 - 90% of the power consumption of the booster, saving 3,492,720 - 4,490,640 kWh of electricity per year, and also saves the initial investment of the compressor 10, which can effectively reduce the production cost for the enterprise. At the same time, the double soda process section does not need to set up a CO 2 compressor anymore, saving huge investment and operating costs.

[0039] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An energy-saving system for coupling the production of soda ash by combining the flash vapor and concentrated gas of methanol-eluted carbon dioxide, comprising a scrubbing tower (1), a first flash tank (2), a second flash tank (3), a carbonation tower (5), a purification tower (6), a low-pressure regeneration system (8), a centrifuge (7), a circulation pump (9) and various connecting pipelines; the scrubbing tower (1) includes a lower desulfurization section and an upper decarbonization section; the liquid-phase inlet of the first flash tank (2) is connected to the liquid-phase outlet of the upper decarbonization section; the liquid-phase inlet of the second flash tank (3) is connected to the liquid-phase outlet of the lower desulfurization section, characterized in that: The system further includes a desulfurization tower (4); the liquid-phase inlet of the desulfurization tower (4) is connected to the bottom liquid-phase outlet of the first flash tank (2), and the gas-phase inlet of the desulfurization tower (4) is connected to the upper gas-phase outlet of the second flash tank (3); the upper gas-phase outlet of the first flash tank (2) and the upper gas-phase outlet of the desulfurization tower (4) are both connected to the gas-phase inlet of the carbonation tower (5); the bottom liquid-phase outlet of the second flash tank (3) and the bottom liquid-phase outlet of the desulfurization tower (4) are both connected to the inlet of the low-pressure regeneration system (8); the regenerated lean methanol liquid of the low-pressure regeneration system (8) is connected to the upper decarbonization section liquid-phase inlet of the scrubbing tower (1) through a circulation pump (9), and the regenerated CO 2 gas is connected to the user or vented; the acidic gas outlet containing H 2 S and CO 2 of the low-pressure regeneration system (8) is connected to the sulfur recovery section; the top gas-phase outlet of the purification tower (6) is connected to the gas-phase inlet of the lower desulfurization section of the scrubbing tower (1); a booster (11) is provided on the pipeline connecting the top gas-phase outlet of the purification tower (6) and the gas-phase inlet of the lower desulfurization section of the scrubbing tower (1).

2. An energy-saving system for coupling the production of soda ash by combining the flash vapor and concentrated gas of methanol-eluted carbon dioxide according to claim 1, characterized in that: Valves for adjusting the material flow in the pipeline according to the liquid level of the equipment are provided at the bottom liquid-phase outlet ends of the lower desulfurization section, the upper decarbonization section, the first flash tank (2), the second flash tank (3), the desulfurization tower (4) and the purification tower (6).

3. An energy-saving system for coupling the production of soda ash by combining the flash vapor and concentrated gas of methanol-eluted carbon dioxide according to claim 1, characterized in that: A centrifuge (7) capable of performing solid-liquid separation is provided at the bottom material outlet end of the carbonation tower (5), and a valve for adjusting the material flow in the pipeline according to the liquid level of the equipment is also provided at the bottom material outlet end of the carbonation tower (5).

4. An energy-saving process for coupling the production of soda ash by combining the flash vapor and concentrated gas of methanol-eluted carbon dioxide, using the energy-saving system for coupling the production of soda ash by combining the flash vapor and concentrated gas of methanol-eluted carbon dioxide according to any one of claims 1-3, characterized in that: The specific process is as follows: The shifted gas enters the lower desulfurization section of the scrubbing tower (1) and is washed with the rich CO methanol coming from the upper decarbonization section. 2 The H2S in the shifted gas is completely removed, and then the gas enters the upper decarbonization section. After being washed with the lean solution of decarbonized methanol, the CO2 is removed until the shifted gas purification requirements are met. 2 The purified gas coming out from the top of the scrubbing tower (1) goes to the subsequent process section. 2 ​ The H-free gas discharged from the decarbonization section at the top of the scrubbing tower (1) 2 The S-methanol-rich liquid enters the first flash tank (2); the H-containing liquid discharged from the desulfurization section at the bottom of the scrubbing tower (1) 2 The S-methanol-rich liquid enters the second flash tank (3), and the H-containing gas phase outlet from the upper part of the first flash tank (2) 2 ,CO,CO 2 The first flash gas decarbonization tower (5); the H-containing gas phase outlet from the upper part of the second flash tank (3) 2 ,CO,CO 2、 H 2 The second flash gas of S goes to the desulfurization tower (4), and the liquid phase outlet at the bottom of the first flash tank (2) does not contain H 2 After the methanol-rich liquid of S is washed and desulfurized in the desulfurization tower (4), the gas is sent to the carbonization tower (5); in the carbonization tower (5), the first flash gas from the upper gas phase outlet of the first flash tank (2) and the gas after desulfurization from the upper gas phase outlet of the desulfurization tower (4) react with the ammonia salt water to generate ammonium chloride and sodium bicarbonate, the lower material from the bottom material outlet of the carbonization tower (5) is treated in the centrifuge (7), the solid product sodium bicarbonate is sent to the calcination section, and the mother liquor is recycled after being separated by ammonia absorption, salt dissolution and ammonium chloride; the tail gas from the top gas phase outlet of the carbonization tower (5) is sent to the purification tower (6), the tail gas is washed with washing water in the purification tower (6), and then pressurized by the booster (11) and returned to the washing tower (1) for recycling, and the washing liquid from the bottom liquid phase outlet of the purification tower (6) is sent to the salt dissolution or ammonia absorption section; The methanol-rich liquid containing H 2 S from the bottom liquid phase outlet of the second flash tank (3) and the washing liquid from the bottom liquid phase outlet of the desulfurization tower (4) both return to the low-pressure regeneration system (8). The acid gas containing H 2 S and CO 2 after being treated by the low-pressure regeneration system (8) goes to the sulfur recovery section. The lean liquid after being treated by the low-pressure regeneration system (8) goes to the upper decarbonization section of the washing tower (1) after passing through the circulation pump (9). The low-pressure CO 2 goes to the user or is vented.

5. An energy-saving process for coupling the production of soda ash by combining the flash vapor and concentrated gas of methanol-eluted carbon dioxide according to claim 4, characterized in that: The pressures of the first flash tank (2), the second flash tank (3) and the desulfurization tower (4) are all set to 0.5 - 2.0 Mpa according to the requirements of the combined soda process for the CO 2 quantity.

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