Methanol preparation system based on solid oxide battery

Abstract

The invention belongs to the field of methanol preparation, and particularly discloses a methanol preparation system based on a solid oxide battery, which comprises a high-temperature gasification unit used for producing crude synthesis gas from coal-water slurry; the gas purification-conversion unit is used for purifying and blending crude synthesis gas; the methanol synthesis-separation unit is used for catalyzing the synthesis gas to be converted into crude methanol and separating out the product methanol; a solid oxide battery unit switchable between a solid oxide fuel cell mode and a solid oxide electrolytic cell mode; releasing electric energy and generating water and carbon dioxide in a solid oxide fuel cell mode; water and carbon dioxide are electrolyzed in a solid oxide electrolytic cell mode to produce syngas required by the methanol synthesis-separation unit to produce crude methanol. Through the structural design, the solid oxide battery unit is highly coupled with a methanol synthesis process, efficient production of methanol and carbon emission control are realized, and remarkable energy-saving and emission-reducing effects are achieved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of methanol preparation, more specifically, relates to a methanol preparation system based on solid oxide cell. BACKGROUND

[0002] Coal-to-methanol is one of the basic routes in the field of coal chemical industry, and is also an important way to ensure the self-sufficiency of liquid fuel and chemical raw materials. The traditional coal-to-methanol process usually adopts coal water slurry gasification to produce raw synthesis gas, purifies the raw synthesis gas, and then processes it through a water-gas shift unit, and then processes it through a methanol synthesis reactor to synthesize raw methanol, and finally obtains methanol products through rectification.

[0003] In the related art, when the methanol synthesis reactor converts synthesis gas (a mixture of carbon monoxide and hydrogen) into methanol, the single-pass conversion rate is generally only about 15-25%, and a large amount of unreacted gas needs to be recycled, compressed, and reheated, causing additional steam and power consumption; and low conversion rate means that several times the theoretical value of synthesis gas needs to be processed to produce one ton of methanol, significantly increasing the load of the reactor, compressor and cooling system, and increasing carbon emissions, causing resource waste and increased pollution. SUMMARY

[0004] In view of the defects of the prior art, the present application provides a methanol preparation system based on solid oxide cell, aiming to solve the problem of low conversion rate of the existing methanol synthesis reactor, thereby causing additional steam and power consumption, and increasing carbon emissions, causing resource waste and increased pollution.

[0005] The methanol preparation system based on solid oxide cell provided by the present application specifically comprises: a high-temperature gasification unit for causing the coal water slurry to undergo an oxidation reaction to produce raw synthesis gas; a gas purification-shifting unit, the input end of which is in communication with the output end of the high-temperature gasification unit, for purifying and adjusting the raw synthesis gas; a methanol synthesis-separation unit, the input end of which is in communication with the output end of the gas purification-shifting unit, for catalytically converting synthesis gas into raw methanol and separating out product methanol; a solid oxide cell unit, which can be switched between solid oxide fuel cell mode and solid oxide electrolysis cell mode; the anode input end of the solid oxide cell unit is in communication with the output end of the gas purification-shifting unit, and in the solid oxide fuel cell mode, it releases electric energy and produces water and carbon dioxide; the cathode output end of the solid oxide cell unit is in communication with the input end of the methanol synthesis-separation unit, and in the solid oxide electrolysis cell mode, it electrolyzes water and carbon dioxide to produce synthesis gas required by the methanol synthesis-separation unit to generate raw methanol.

[0006] Compared with the prior art, the above technical scheme conceived by the present application has the beneficial effects of improving methanol production, external power generation, energy saving, carbon reduction and emission reduction.

[0007] As a further preferred, the solid oxide cell unit is a reversible solid oxide cell stack.

[0008] As a further preferred, the output end of the gas purification and transformation unit is connected to the input end of the methanol synthesis and separation unit and the anode input end of the solid oxide cell unit through a three-way pipe, and a shunt valve is fixedly installed on the three-way pipe to adjust the flow ratio of the synthesis gas entering the gas purification and transformation unit and the solid oxide cell unit.

[0009] As a further preferred, the methanol synthesis and separation unit comprises a methanol synthesis reactor, a condenser and a rectifying tower connected in series, the methanol synthesis reactor is used for catalytically converting synthesis gas into crude methanol, the condenser is used for cooling and separating crude methanol, and the rectifying tower is used for removing light and heavy components to obtain product methanol.

[0010] As a further preferred, the unreacted synthesis gas outlet of the methanol synthesis reactor is communicated with the input end thereof through a circulating compressor to form a synthesis gas circulating loop.

[0011] As a further preferred, a branch pipeline is arranged on the synthesis gas circulating loop, and the branch pipeline is communicated with the anode input end of the solid oxide cell unit.

[0012] As a further preferred, the methanol preparation system further comprises a high-temperature heat exchanger arranged between the high-temperature gasification unit and the gas purification and transformation unit and communicated with the solid oxide cell unit, which is used for recovering the heat of the crude synthesis gas and providing the heat to the solid oxide cell unit.

[0013] As a further preferred, the gas purification and transformation unit comprises a low-temperature methanol wash device and an isothermal water gas shift reactor connected in series, the low-temperature methanol wash device is used for desulfurizing and decarbonating the crude synthesis gas, and the isothermal water gas shift reactor is used for adjusting the ratio of hydrogen and carbon monoxide in the crude synthesis gas.

[0014] As a further preferred, the methanol preparation system further comprises a slurry preparation-conveying unit for preparing and conveying coal water slurry to the high-temperature gasification unit.

[0015] Overall, compared with the prior art, the above technical solutions conceived by the present application mainly have the following technical advantages: 1. The present application combines traditional coal-to-methanol with solid oxide cell units, the methanol synthesis-separation unit catalytically converts part of the synthesis gas into methanol, the solid oxide cell unit generates electricity using part of the synthesis gas, realizes electricity recovery, and electrolyzes the generated tail gas to generate synthesis gas to be injected into the methanol synthesis-separation unit again, replacing or supplementing the synthesis gas from the original coal source, realizing material circulation and carbon resource utilization, while effectively reducing the load of the methanol synthesis-separation unit, realizing efficient production of methanol.

[0016] 2. The present application converts part of the synthesis gas into electricity through the solid oxide fuel cell mode of the solid oxide cell unit, while generating high-temperature tail gas rich in carbon dioxide, realizing energy recovery and carbon dioxide enrichment.

[0017] 3. The present application electrolyzes the captured carbon dioxide and water vapor to generate synthesis gas and inject it into the methanol synthesis-separation unit through the solid oxide electrolysis cell mode of the solid oxide cell unit, forming a material circulation closed loop, reducing coal consumption and reducing carbon emissions.

[0018] 4. The present application couples the high-temperature tail gas and electricity of the solid oxide fuel cell mode of the solid oxide cell unit with the high-temperature electrolysis demand of the solid oxide electrolysis cell mode, realizes optimization of heat and electricity, improves overall energy efficiency, and improves methanol production and carbon dioxide recovery efficiency; at the same time, the heat of the raw synthesis gas is effectively recovered and utilized through the high-temperature heat exchanger, saving energy. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 is the flow chart of the methanol preparation system provided by the embodiment of the present application.

[0020] In all the drawings, the same reference signs are used to represent the same elements or structures, wherein: 1. Slurry preparation-conveying unit; 2. High-temperature gasification unit; 3. Gas purification-transformation unit; 4. Methanol synthesis-separation unit; 5. Solid oxide cell unit; 6. High-temperature heat exchanger. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical solutions and advantages of the present application more clear and explicit, the present application will be further described in detail below in combination with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and do not limit the present application.

[0022] Referring to Figure 1 The methanol preparation system based on solid oxide cell disclosed in the present application comprises a slurry preparation and delivery unit 1, a high-temperature gasification unit 2, a gas purification and transformation unit 3, a methanol synthesis and separation unit 4, a solid oxide cell unit 5 and a high-temperature heat exchanger 6, wherein the slurry preparation and delivery unit 1, the high-temperature gasification unit 2, the high-temperature heat exchanger 6 and the gas purification and transformation unit 3 are connected in series, and the gas output end of the gas purification and transformation unit 3 is connected with the methanol synthesis and separation unit 4 and the solid oxide cell unit 5.

[0023] In the embodiment, the raw coal is prepared into coal water slurry by the slurry preparation and delivery unit 1, and the coal water slurry is delivered to the high-temperature gasification unit 2; the input end of the high-temperature gasification unit 2 is communicated with the output end of the slurry preparation and delivery unit 1, and the coal water slurry is subjected to oxidation reaction in the high-temperature gasification unit 2 to generate crude synthesis gas; the input end of the gas purification and transformation unit 3 is communicated with the output end of the high-temperature gasification unit 2 through the high-temperature heat exchanger 6, which is used for purifying and adjusting the crude synthesis gas; the heat output end of the high-temperature heat exchanger 6 is communicated with the solid oxide cell unit 5, which is used for recovering the heat of the crude synthesis gas and providing the heat to the solid oxide cell unit 5; the input end of the methanol synthesis and separation unit 4 is communicated with the output end of the gas purification and transformation unit 3, which is used for catalytically converting a part of the synthesis gas into crude methanol and separating the product methanol; since the conversion rate of the existing methanol synthesis reactor is low, a large amount of unreacted gas needs to be recycled, compressed and reheated, which causes additional steam and power consumption. Based on this, the system can generate electricity by using part of the synthesis gas through the setting of the solid oxide cell unit 5, improve the resource utilization rate and reduce carbon emissions.

[0024] Specifically, the raw coal is crushed and wet ground in the slurry preparation and delivery unit 1, and then 55wt%-65wt% coal water slurry is prepared, a dispersing agent and a stabilizing agent are added into the coal water slurry to ensure that the coal water slurry does not settle for 72 hours, and the coal water slurry is delivered to the high-temperature gasification unit 2 through a delivery pump; in the high-temperature gasification unit 2, the coal water slurry is burned with 95% pure oxygen in parallel flow, and high-temperature tail gas and solid residues are generated through high-temperature oxidation reaction to generate crude synthesis gas containing carbon monoxide, hydrogen, carbon dioxide and a small amount of light hydrocarbons; the crude synthesis gas is delivered to the gas purification and transformation unit 3, which is used for cooling, dust removal, desulfurization and hydrogen / carbon monoxide ratio adjustment of the crude synthesis gas to meet the raw material requirements of the methanol catalytic synthesis reaction; the purified synthesis gas is delivered to the methanol synthesis and separation unit 4, which receives the purified and adjusted synthesis gas and generates methanol products through catalytic reaction, and the products are condensed and rectified to obtain finished methanol. Since the process of “raw coal to synthesis gas—synthesis gas to methanol” is a mature process, it is not the innovation point of the present application, and therefore will not be described in detail.

[0025] In the system, the solid oxide cell 5 can switch between a solid oxide fuel cell mode (SOFC) and a solid oxide electrolysis cell mode (SOEC), preferably a reversible solid oxide cell stack; the anode input end of the solid oxide cell 5 is in communication with the output end of the gas purification and conversion unit 3, and the solid oxide cell 5 is provided with reaction fuel through the gas purification and conversion unit 3, and the solid oxide cell 5 releases electric energy and generates water and high-temperature tail gas rich in carbon dioxide in the solid oxide fuel cell mode, facilitating capture and utilization; the cathode output end of the solid oxide cell 5 is in communication with the input end of the methanol synthesis and separation unit 4, and the solid oxide cell 5 electrolyzes the captured water and carbon dioxide to generate synthesis gas (hydrogen / carbon monoxide) required by the methanol synthesis and separation unit 4 to generate crude methanol in the solid oxide electrolysis cell mode, and the synthesis gas is injected back to the methanol synthesis and separation unit 4 to replace or supplement the synthesis gas from the original coal source, realizing material circulation and carbon resource utilization. The following reaction formula can be used for illustration: SOFC mode (power generation): absorption of synthesis gas → electric power + high-temperature carbon dioxide / water; SOEC mode (electrolysis): absorption of carbon dioxide / water → synthesis gas (hydrogen + carbon monoxide).

[0026] The excess carbon dioxide released in the solid oxide fuel cell mode can be collected for industrial production, such as synthesizing urea, dimethyl carbonate (environmentally friendly solvent) using carbon dioxide as raw material, and using dry ice for preservation, realizing material circulation and carbon resource utilization. The system can flexibly adjust the operation strategy of SOFC and SOEC according to actual load and power supply, i.e., adjusting the operation time ratio of SOFC and SOEC according to power generation demand and methanol production demand, realizing the collaborative optimization of methanol yield, energy efficiency and carbon dioxide recovery efficiency, so as to balance economy and environmental friendliness, and has multiple advantages such as energy saving and emission reduction, resource efficient utilization, and renewable energy access adaptability.

[0027] More specifically, the output end of the gas purification and conversion unit 3 is connected to the input end of the methanol synthesis and separation unit 4 and the anode input end of the solid oxide cell 5 through a three-way pipe, so that the synthesis gas can controllably enter the input end of the methanol synthesis and separation unit 4 and the solid oxide cell 5; a shunt valve is fixedly installed at the shunt of the three-way pipe to adjust the flow ratio of the synthesis gas entering the gas purification and conversion unit 3 and the solid oxide cell 5, ensuring safe and stable operation of the device.

[0028] Further, the gas purification and transformation unit 3 in the embodiment includes a low-temperature methanol washing device and an isothermal water gas shift reactor connected in series, the crude synthesis gas enters the low-temperature methanol washing device and the isothermal water gas shift reactor in series, the low-temperature methanol washing device is used for desulfurization and decarbonization of the crude synthesis gas, and the isothermal water gas shift reactor is used for adjusting the ratio of hydrogen and carbon monoxide in the crude synthesis gas. The methanol synthesis and separation unit 4 includes a methanol synthesis reactor, a condenser and a rectifying tower connected in series, the methanol synthesis reactor is used for catalytically converting the synthesis gas into crude methanol, the condenser is used for cooling and separating the crude methanol, and the rectifying tower is used for removing light and heavy components and obtaining product methanol.

[0029] Further, the unreacted synthesis gas outlet of the methanol synthesis reactor is connected to the input end thereof through a circulating compressor to form a synthesis gas circulating loop, the main function of the loop is to send the unreacted synthesis gas back to the methanol synthesis reactor to make it continue to participate in the reaction, thereby improving the utilization rate of the synthesis gas and the yield of methanol. In addition, a branch pipeline is arranged on the synthesis gas circulating loop, the branch pipeline is connected to the anode input end of the solid oxide cell unit 5, and the function of the branch pipeline is to send part of the circulating synthesis gas to the anode input end of the solid oxide cell unit 5 as fuel gas, so that the solid oxide cell unit 5 can generate electricity in the solid oxide fuel cell mode (SOFC) by using the synthesis gas, release electric energy and produce water and high-temperature tail gas rich in carbon dioxide, which is convenient for subsequent capture and utilization. This design not only improves the utilization rate of resources, but also reduces carbon emissions, realizes efficient utilization of material circulation and carbon resources.

[0030] The methanol preparation system in the application realizes efficient production of methanol and carbon emission control through high coupling of the solid oxide cell unit 5 and the methanol synthesis process, and has a significant energy-saving and emission-reducing effect.

[0031] It should be understood that the expressions such as "include" and "may include" used in the application represent the existence of the disclosed functions, operations or constituent elements, and do not limit one or more additional functions, operations and constituent elements. In the application, terms such as "include" and / or "have" can be interpreted to represent a specific feature, number, operation, constituent element, component or combination thereof, but cannot be interpreted to exclude the existence or addition of one or more other features, numbers, operations, constituent elements, components or combinations thereof.

[0032] It should be understood that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0033] In addition, the terms "first", "second", "third", etc. are used only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "a plurality of" is two or more, unless otherwise explicitly specified and limited.

[0034] In the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connecting", "fixing" and the like should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0035] Those skilled in the art can understand that the above only describes the preferred embodiments of the present application, and is not intended to limit the present application, and any modifications, equivalent replacements and improvements made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A solid oxide cell based methanol production system, characterized by, The system comprises: a high-temperature gasification unit (2) for causing coal water slurry to undergo an oxidation reaction to produce a crude synthesis gas; a gas purification-reforming unit (3) having an input end in communication with an output end of the high-temperature gasification unit (2) for purifying and reforming the crude synthesis gas; a methanol synthesis-separation unit (4) having an input end in communication with an output end of the gas purification-reforming unit (3) for catalytically converting the synthesis gas into a crude methanol and separating the product methanol; a solid oxide cell unit (5) switchable between a solid oxide fuel cell mode and a solid oxide electrolysis cell mode; an anode input end of the solid oxide cell unit (5) is in communication with an output end of the gas purification-reforming unit (3) to release electric energy and produce water and carbon dioxide in the solid oxide fuel cell mode; a cathode output end of the solid oxide cell unit (5) is in communication with an input end of the methanol synthesis-separation unit (4) to electrolyze the water and carbon dioxide to produce the synthesis gas required by the methanol synthesis-separation unit (4) to generate the crude methanol in the solid oxide electrolysis cell mode.

2. A solid oxide cell based methanol production system according to claim 1, characterized in that, The solid oxide cell unit (5) is a reversible solid oxide cell stack.

3. A solid oxide cell based methanol production system as claimed in claim 1, characterized in that, The output end of the gas purification-reforming unit (3) is connected to both the input end of the methanol synthesis-separation unit (4) and the anode input end of the solid oxide cell unit (5) through a tee pipe, and a flow dividing valve is fixedly installed on the tee pipe to adjust the flow ratio of the synthesis gas entering the gas purification-reforming unit (3) and the solid oxide cell unit (5).

4. A solid oxide cell based methanol production system according to claim 3, wherein, The methanol synthesis-separation unit (4) comprises a methanol synthesis reactor, a condenser and a rectifying tower connected in series; the methanol synthesis reactor is used for catalytically converting the synthesis gas into a crude methanol; the condenser is used for cooling and separating the crude methanol; and the rectifying tower is used for removing light and heavy components and obtaining the product methanol.

5. A solid oxide cell based methanol production system according to claim 4, wherein, An unreacted synthesis gas outlet of the methanol synthesis reactor is connected to the input end thereof through a circulating compressor to form a synthesis gas circulating loop.

6. A solid oxide cell based methanol production system according to claim 5, wherein, A branch pipeline is provided on the synthesis gas circulating loop and is in communication with the anode input end of the solid oxide cell unit (5).

7. A solid oxide cell based methanol production system as claimed in claim 1, wherein, The methanol production system further comprises a high-temperature heat exchanger (6) provided between the high-temperature gasification unit (2) and the gas purification-reforming unit (3) and in communication with the solid oxide cell unit (5) to recover the heat of the crude synthesis gas and provide it to the solid oxide cell unit (5).

8. A solid oxide cell based methanol production system as claimed in claim 1, characterized in that, The gas purification-reforming unit (3) comprises a low-temperature methanol wash device and an isothermal water gas shift reactor connected in series; the low-temperature methanol wash device is used for desulfurizing and decarbonating the crude synthesis gas; and the isothermal water gas shift reactor is used for adjusting the ratio of hydrogen and carbon monoxide in the crude synthesis gas.

9. A solid oxide cell based methanol production system as claimed in claim 1, characterized in that, The methanol production system further comprises a slurry preparation and delivery unit (1) for preparing and delivering coal water slurry to the high-temperature gasification unit (2).

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