Solid oxide battery technology and coal chemical coupling system and operation method thereof

Abstract

The invention relates to the technical field of energy conservation and emission reduction, and particularly provides a solid oxide cell technology and coal chemical industry coupling system and an operation method thereof, and the system comprises a coal chemical industry section, a solid oxide fuel cell power generation section and a solid oxide electrolytic cell water electrolysis hydrogen production section. According to the method, a solid oxide electrolytic cell technology is adopted, green electricity hydrogen production is used for supplementing hydrogen to replace a conversion section in the coal chemical process, so that generation of carbon dioxide is reduced, consumption of CO is avoided, in addition, the solid oxide electrolytic cell can also electrolyze CO2, CO2 is converted into CO and oxygen to serve as reaction raw materials, and the carbon reduction effect is achieved; the problems of large carbon emission and CO2 capture and utilization in the production process of coal chemical enterprises are effectively solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of energy conservation and emission reduction, and specifically relates to a solid oxide battery technology and coal chemical coupling system and an operation method thereof. Background Art

[0002] For traditional coal chemical enterprises, the synthesis gas (CO+H2) produced by coal gasification is mostly used to synthesize chemical products such as methanol. Figure 2 As shown in the figure, the typical process flow is as follows: the crude synthesis gas produced by coal gasification enters the low-temperature methanol elution to remove impurities such as CO2, H2S, organic sulfur (COS, CS2) in the crude coal gas through the conversion reaction (CO+H2O=CO2+H2), and the clean coal gas is obtained as methanol synthesis gas for methanol synthesis. After methanol synthesis, the remaining raw gas is used as circulating gas for methanol synthesis, and the other is the relaxation gas. It passes through the hydrogen recovery device to obtain hydrogen-rich gas, and the remaining tail gas enters the fuel gas pipeline. In this process, the conversion section is the main link for the production of carbon dioxide, accounting for about 20% of the coal chemical production process. This process is to adjust the hydrogen-carbon ratio of methanol synthesis gas and increase the proportion of hydrogen, but the conversion reaction consumes another raw material CO for methanol synthesis and converts it into greenhouse gas CO2. According to relevant literature, the carbon dioxide produced in the conversion section accounts for about 70% of the total carbon emissions of coal chemical enterprises.

[0003] Solid oxide electrolyzers and solid oxide fuel cells are reversible processes of the same type of devices. Solid oxide fuel cells can use hydrogen, CO, CH4, etc. as fuels to react and generate water and CO2; solid oxide electrolyzers can electrolyze water and carbon dioxide separately, and can also co-electrolyze water and carbon dioxide to produce synthesis gas. The integrated gasification fuel cell (IGFC) technology using solid oxide fuel cell technology is now in demonstration operation. IGFC is a clean and efficient green coal-fired power technology. Combined with CO2 capture technology, it can achieve a high power generation efficiency of more than 60% and achieve near-zero CO2 emissions. IGFC mainly includes three modules: coal gasification and purification, fuel cell power generation, and exhaust gas combustion waste heat recovery. The mixed gas of CO2 and H2O obtained from combustion can be coupled with CO2 capture and storage technology. Such as Figure 3As shown in the figure, the general process of IGFC is that coal (or natural gas, biomass, etc.) is gasified to generate synthesis gas. After heat recovery, the synthesis gas enters the purification unit to remove harmful substances such as sulfur and dust. The purified gas is sent to the anode side of the high-temperature fuel cell (including solid oxide fuel cell and molten carbonate fuel cell), and air is introduced into the cathode side. The fuel gas and the oxidizing gas react electrochemically in the cell to generate electricity. During the reaction, most of the combustible components are converted into electricity and heat. The unconverted combustible components are discharged with the battery anode tail gas and enter the combustion chamber for catalytic combustion, and are all converted into CO2 and H2O. After the heat of the mixed gas is recovered and H2O is condensed, CO2 gas with a purity of more than 90% is obtained, which can be directly captured and sealed.

[0004] The existing IGFC technology uses high-concentration syngas (CO+H2) produced by coal gasification as fuel for high-temperature fuel cell power generation. This solution is suitable for large coal-fired power plants. However, for traditional coal chemical companies, high-concentration syngas (CO+H2) is an important chemical raw material for producing chemical products such as methanol, dimethyl ether, and acetic acid. In addition, the manufacturing cost is high, and it is not economical to use it directly as fuel for power generation.

[0005] In the process of coal gasification, the problem of insufficient hydrogen content often occurs. Now the shift reaction is used to generate hydrogen by the reaction of water and carbon monoxide (CO+H2O=CO2+H2). This process increases the content of hydrogen at the expense of CO and produces a large amount of CO2. Summary of the invention

[0006] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a solid oxide battery technology and coal chemical coupling system and its operation method, which adopts solid oxide electrolysis cell technology and utilizes green electricity to produce hydrogen to supplement hydrogen to replace the conversion section in the coal chemical process, thereby reducing the production of carbon dioxide and avoiding the consumption of CO. In addition, the solid oxide electrolysis cell can also electrolyze CO2, convert CO2 into CO and oxygen as reaction raw materials, thereby playing a role in carbon reduction, and solving the problem of large carbon emissions and CO2 capture and utilization in the production process of coal chemical enterprises.

[0007] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: a solid oxide battery technology and coal chemical coupling system, including a coal chemical section, a solid oxide fuel cell power generation section and a solid oxide electrolysis cell water electrolysis hydrogen production section; The coal chemical industry section includes a coal gasification unit for producing raw coal gas, and the coal chemical industry section also includes a conversion section, a low-temperature methanol washing unit, a methanol synthesis unit, a methanol distillation unit, a methanol storage tank, a refined methanol export unit and a hydrogen recovery unit which are sequentially connected to the output end of the coal gasification unit. A part of the purge gas generated during the synthesis process of the methanol synthesis unit is continuously transported to the methanol synthesis unit as circulating gas to participate in methanol synthesis, another part of the purge gas is recycled through the hydrogen recovery unit to obtain hydrogen-rich gas to be circulated as synthesis gas to synthesize methanol, and another part of the tail gas after hydrogen recovery of the methanol purge gas is used as fuel for the solid oxide fuel cell power generation section; The solid oxide fuel cell power generation section includes a solid oxide fuel cell, a fuel preheater, a burner and a carbon dioxide capture unit. The solid oxide fuel cell includes an anode and a cathode. The tail gas after hydrogen recovery by the hydrogen recovery device is preheated by the fuel preheater and enters the solid oxide fuel cell anode. H2, CO, and CH4 in the tail gas are converted into CO2 and water. The remaining tail gas is burned by the burner and the CO2 in the flue gas is captured and recovered by the carbon dioxide capture unit. The captured CO2 is electrolyzed into CO and O2 by the solid oxide electrolysis cell water electrolysis hydrogen production section. The solid oxide electrolysis cell water electrolysis hydrogen production section comprises a solid oxide electrolysis cell, the solid oxide electrolysis cell comprises a fuel electrode and an air electrode, the solid oxide electrolysis cell generates hydrogen and oxygen by electrolyzing water, wherein the hydrogen enters the conversion section to supplement the hydrogen, and the oxygen enters the coal chemical section as an oxygen source; The system also includes three external supply input units, namely a water supply unit, an air supply unit and a green electricity supply unit, wherein the green electricity generated by the green electricity supply unit electrolyzes water to produce hydrogen and oxygen through the solid oxide electrolysis cell, the water supply unit is used to supply an input water source to the solid oxide electrolysis cell, one path of the air supply unit is connected to the air electrode of the solid oxide electrolysis cell, and the oxygen generated by the air electrode is blown out of the fuel cell stack into the coal chemical section as an oxygen source, and the other path of the air supply unit enters the cathode of the solid oxide fuel cell, and the oxygen in the air and the fuel undergo electrochemical reactions at the anode and cathode of the solid oxide fuel cell to generate electrical energy.

[0008] Preferably, the water supply unit includes a water purifier, a water storage tank, a water pump and a water vapor generator which are connected in sequence.

[0009] Preferably, the air supply unit comprises a blower, a dryer, a filter and an air preheater which are connected in sequence.

[0010] Preferably, the green electricity supply unit is renewable energy power generation, at least one of wind power generation, hydropower generation, solar power generation, biomass power generation, ocean power generation, and geothermal power generation.

[0011] Preferably, the raw material sources of the coal gasification unit are coal powder, coal-water slurry, coal char, water vapor and oxygen from air separation.

[0012] A method for operating a solid oxide battery technology and coal chemical industry coupling system, comprising: S1, coal chemical industry section: The raw coal gas is produced by using coal powder, water-coal slurry, coal coke, water vapor and oxygen from air separation as raw materials through the coal gasification process; The raw coal gas is converted into hydrogen and carbon dioxide by the reaction of water and carbon monoxide in the conversion stage, and the hydrogen-carbon ratio is adjusted to form raw synthesis gas; The synthesis gas is obtained by removing sulfide and carbon dioxide through a low-temperature methanol washing unit; The carbon monoxide in the synthesis gas reacts with hydrogen through a methanol synthesis unit to produce crude methanol; A methanol distillation device is used to remove water and other organic impurities contained in crude methanol to obtain refined methanol, which is stored in a methanol storage tank and sold externally; Part of the off-gas generated during the synthesis process of the methanol synthesis unit is continuously transported to the methanol synthesis unit as circulating gas to participate in methanol synthesis, another part of the off-gas is recycled through a hydrogen recovery unit to recover hydrogen to obtain hydrogen-rich gas, which is circulated as synthesis gas to synthesize methanol, and another part of the tail gas after hydrogen recovery from the methanol off-gas is used as fuel for the power generation section of the solid oxide fuel cell; S2, Solid Oxide Fuel Cell Power Generation Section: The tail gas recovered from methanol relaxation gas and hydrogen in the coal chemical industry is used as the fuel of the solid oxide fuel cell. The tail gas is preheated by the fuel preheater and enters the solid oxide fuel cell anode to react. The H2, CO, and CH4 in the tail gas are converted into CO2 and water. The remaining tail gas is burned by the burner and the CO2 in the flue gas is captured and recovered by the carbon dioxide capture unit. The captured CO2 is electrolyzed into CO and O2 by the solid oxide electrolysis cell. The air is pressurized by a blower and the moisture in the air is removed by a dryer. The impurities in the air are removed by a filter. The air is preheated by an air preheater and then enters the cathode of the solid oxide fuel cell. The oxygen and fuel in the air undergo an electrochemical reaction at the anode and cathode of the solid oxide fuel cell, causing electron transfer to generate electrical energy. After passing through a DC / DC regulator and inverter, the electrical energy is output and supplied to other electrical equipment. S3, solid oxide electrolysis cell water electrolysis hydrogen production section: Green electricity generated by renewable energy is used to electrolyze water in a solid oxide electrolysis cell to produce hydrogen and oxygen. The hydrogen enters the conversion section to supplement hydrogen and is used to replace the conversion section. The oxygen enters the coal gasification section as an oxygen source to replace the oxygen in the air separation. After being purified by the purifier, the water is stored in a water tank, pressurized by a water pump, and then enters a steam generator to be heated into steam, which then enters the fuel electrode of the solid oxide electrolysis cell to undergo an electrochemical reaction to produce hydrogen. The hydrogen is transported to the conversion section to reduce the scale or eliminate it, and the oxygen ions produced by the fuel electrode pass through the electrolyte to react at the air electrode to produce oxygen. The air is pressurized by a blower, the dryer removes moisture from the air, the filter removes impurities from the air, and after being preheated by an air preheater, it enters the air electrode of the solid oxide electrolysis cell. The oxygen produced by the air electrode is blown out of the fuel cell and enters the coal chemical section as an oxygen source. In addition, water and CO2 are simultaneously electrolyzed in the solid oxide electrolysis cell to prepare synthesis gas as a raw material for methanol synthesis.

[0013] Compared with the prior art, the present invention has the following beneficial effects: 1. Compared with the traditional coal chemical conversion stage, the solid oxide electrolysis cell technology in the solid oxide battery technology is used to electrolyze water to produce hydrogen to make up for the problem of insufficient hydrogen content in the coal gasification process, reduce or avoid the consumption of CO and thus reduce the production of CO2. In addition, the tail gas recovered from the methanol relaxation gas hydrogen can be used as a fuel for solid oxide fuel cells to generate electricity, and the carbon dioxide in the tail gas is enriched and then electrolyzed with water and carbon dioxide using solid oxide electrolysis cell technology to prepare synthesis gas (CO+H2), and CO2 is reused as a raw material, which can fundamentally solve the problem of large carbon emissions from coal chemical enterprises.

[0014] 2. Compared with the traditional IGFC technology, this solution does not directly use high-value-added high-concentration synthesis gas to generate electricity, but uses the exhaust gas recovered from methanol purge gas with hydrogen, which has a lower recovery value, to generate electricity. Taking a chemical plant with an annual output of 600,000 tons of methanol as an example, the fuel contained in the exhaust gas after methanol purge gas hydrogen recovery has a one-hour power generation capacity of about 3510kW, which is realistic and feasible. In addition, the exhaust gas recovered from methanol purge gas with hydrogen does not require dust removal, desulfurization and other processes, and the process is simple and low-cost.

[0015] 3. Compared with the traditional exhaust gas treatment method of exhaust gas combustion for heating, the CO2 generated by this solution is very concentrated, easy to capture and utilize, which can greatly reduce the cost of carbon reduction and achieve near-zero carbon dioxide emissions. Taking a chemical plant with an annual output of 600,000 tons of methanol as an example, according to this solution, carbon dioxide emissions can be reduced by about 1,251 kg per hour. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 The process flow chart of the coupling of the solid oxide battery technology and coal chemical industry of the present invention; Figure 2This is a typical process flow chart for coal chemical industry; Figure 3 This is a typical flow chart of IGFC system; Figure 4 Schematic diagram of the working principle of SOFC; Figure 5 Schematic diagram of the working principle of SOEC. DETAILED DESCRIPTION

[0017] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below through embodiments and in conjunction with the accompanying drawings. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0018] Refer to the following Figure 1-Figure 5 To describe a solid oxide battery technology and coal chemical coupling system and its operation method provided in one embodiment of the present application.

[0019] A solid oxide battery technology and coal chemical coupling system, including a coal chemical section, a solid oxide fuel cell power generation section and a solid oxide electrolysis cell water electrolysis hydrogen production section; The coal chemical industry section includes a coal gasification unit for producing raw coal gas, and the coal chemical industry section also includes a conversion section, a low-temperature methanol washing unit, a methanol synthesis unit, a methanol distillation unit, a methanol storage tank, a refined methanol export unit and a hydrogen recovery unit which are sequentially connected to the output end of the coal gasification unit. A part of the purge gas generated during the synthesis process of the methanol synthesis unit is continuously transported to the methanol synthesis unit as circulating gas to participate in methanol synthesis, another part of the purge gas is recycled through the hydrogen recovery unit to obtain hydrogen-rich gas to be circulated as synthesis gas to synthesize methanol, and another part of the tail gas after hydrogen recovery of the methanol purge gas is used as fuel for the solid oxide fuel cell power generation section; The solid oxide fuel cell power generation section includes a solid oxide fuel cell, a fuel preheater, a burner and a carbon dioxide capture unit. The solid oxide fuel cell includes an anode and a cathode. The tail gas after hydrogen recovery by the hydrogen recovery device is preheated by the fuel preheater and enters the solid oxide fuel cell anode. The H2, CO, and CH4 in the tail gas are converted into CO2 and water. The remaining tail gas is burned by the burner and the CO2 in the flue gas is captured and recovered by the carbon dioxide capture unit. The captured CO2 is electrolyzed into CO and O2 by the solid oxide electrolysis cell water electrolysis hydrogen production section. The solid oxide electrolysis cell water electrolysis hydrogen production section includes a solid oxide electrolysis cell, the solid oxide electrolysis cell includes a fuel electrode and an air electrode, the solid oxide electrolysis cell generates hydrogen and oxygen by electrolyzing water, wherein the hydrogen enters the conversion section to supplement the hydrogen, and the oxygen enters the coal chemical section as an oxygen source; The system also includes three external supply input units, namely a water supply unit, an air supply unit and a green electricity supply unit, wherein the green electricity generated by the green electricity supply unit electrolyzes water to produce hydrogen and oxygen through a solid oxide electrolysis cell, the water supply unit is used to supply input water source for the solid oxide electrolysis cell, one route of the air supply unit is connected to the air electrode of the solid oxide electrolysis cell, and the oxygen generated by the air electrode is blown out of the fuel cell stack into the coal chemical section as an oxygen source, and the other route of the air supply unit enters the cathode of the solid oxide fuel cell, and the oxygen in the air and the fuel undergo electrochemical reaction at the anode and cathode of the solid oxide fuel cell to generate electrical energy.

[0020] Furthermore, the water supply unit includes a water purifier, a water storage tank, a water pump and a water vapor generator which are connected in sequence.

[0021] Furthermore, the air supply unit includes a blower, a dryer, a filter and an air preheater which are connected in sequence.

[0022] Furthermore, the green electricity supply unit is renewable energy power generation, which is at least one of wind power generation, hydropower generation, solar power generation, biomass power generation, ocean power generation, and geothermal power generation.

[0023] In a further embodiment, the raw material sources of the coal gasification unit are coal powder, coal-water slurry, coal char, water vapor and oxygen from air separation.

[0024] In a further embodiment, a method for operating a solid oxide battery technology and coal chemical coupling system includes: S1, coal chemical industry section: The raw coal gas is produced by using coal powder, water-coal slurry, coal coke, water vapor and oxygen from air separation as raw materials through the coal gasification process; The raw coal gas is converted into hydrogen and carbon dioxide by the reaction of water and carbon monoxide in the conversion stage, and the hydrogen-carbon ratio is adjusted to form raw synthesis gas; The synthesis gas is obtained by removing sulfide and carbon dioxide through a low-temperature methanol washing unit; The carbon monoxide in the synthesis gas reacts with hydrogen through a methanol synthesis unit to produce crude methanol; A methanol distillation device is used to remove water and other organic impurities contained in crude methanol to obtain refined methanol, which is stored in a methanol storage tank and sold externally; Part of the off-gas generated during the synthesis process of the methanol synthesis unit is continuously transported to the methanol synthesis unit as circulating gas to participate in methanol synthesis, another part of the off-gas is recycled through a hydrogen recovery unit to recover hydrogen to obtain hydrogen-rich gas, which is circulated as synthesis gas to synthesize methanol, and another part of the tail gas after hydrogen recovery from the methanol off-gas is used as fuel for the power generation section of the solid oxide fuel cell; S2, Solid Oxide Fuel Cell Power Generation Section: The tail gas recovered from methanol relaxation gas and hydrogen in the coal chemical industry is used as the fuel of the solid oxide fuel cell. The tail gas is preheated by the fuel preheater and enters the solid oxide fuel cell anode to react. The H2, CO, and CH4 in the tail gas are converted into CO2 and water. The remaining tail gas is burned by the burner and the CO2 in the flue gas is captured and recovered by the carbon dioxide capture unit. The captured CO2 is electrolyzed into CO and O2 by the solid oxide electrolysis cell. The air is pressurized by a blower and the moisture in the air is removed by a dryer. The impurities in the air are removed by a filter. The air is preheated by an air preheater and then enters the cathode of the solid oxide fuel cell. The oxygen and fuel in the air undergo an electrochemical reaction at the anode and cathode of the solid oxide fuel cell, causing electron transfer to generate electrical energy. After passing through a DC / DC regulator and inverter, the electrical energy is output and supplied to other electrical equipment. S3, solid oxide electrolysis cell water electrolysis hydrogen production section: Green electricity generated by renewable energy is used to electrolyze water in a solid oxide electrolysis cell to produce hydrogen and oxygen. The hydrogen enters the conversion section to supplement hydrogen and is used to replace the conversion section. The oxygen enters the coal gasification section as an oxygen source to replace the oxygen in the air separation. After being purified by the purifier, the water is stored in a water tank, pressurized by a water pump, and then enters a steam generator to be heated into steam, which then enters the fuel electrode of the solid oxide electrolysis cell to undergo an electrochemical reaction to produce hydrogen. The hydrogen is transported to the conversion section to reduce the scale or eliminate it, and the oxygen ions produced by the fuel electrode pass through the electrolyte to react at the air electrode to produce oxygen. The air is pressurized by a blower, the dryer removes moisture from the air, the filter removes impurities from the air, and after being preheated by an air preheater, it enters the air electrode of the solid oxide electrolysis cell. The oxygen produced by the air electrode is blown out of the fuel cell and enters the coal chemical section as an oxygen source. In addition, water and CO2 are simultaneously electrolyzed in the solid oxide electrolysis cell to prepare synthesis gas as a raw material for methanol synthesis.

[0025] In this embodiment, the temperature of the methanol purge gas released from the methanol synthesis unit is 41°C, the pressure is 74 bar, and the ratio of circulating gas to methanol purge gas is about 100:1. Although the proportion of methanol purge gas is only 1%, for a chemical plant with an annual output of 600,000 tons of methanol, the flow rate of methanol purge gas is about 399.62 kmol / h (3818 kg / h). The flow rate of hydrogen-rich gas after hydrogen recovery is 287 kmol / h (1267 kg / h), the tail gas flow rate is 112.62 kmol / h (2551 kg / h), and the gas temperature is about 40°C. The main component parameters of the relevant gases are as follows: Table 1 Main components of typical methanol purge gas:

[0026] Table 2 Main composition of hydrogen-rich gas after hydrogen recovery from methanol purge gas:

[0027] Table 3 Main composition of tail gas after hydrogen recovery from methanol purge gas:

[0028] Table 4 Main components of methanol synthesis gas:

[0029] Calculation of power generation from tail gas after hydrogen recovery from methanol purge gas: The exhaust gas flow rate is 2551kg / h (112.62 kmol / h), so the volume flow rate is 112.62×22.4=2522.688Nm3 / h. The gases that can be used for power generation are CO, CH4, and H2.

[0030] The electrical energy per unit volume of CO (kW·h / Nm3) is 3.51; The volume flow rate of CO (Nm3 / h) is 2522.688×16.9×0.01≈426.33; The theoretical power generation capacity of 426.33Nm3 / h CO is 426.33×3.51≈1496.42 kW. The electrical energy per unit volume of CH4 (kW·h / Nm3) is 10; The volume flow rate of CH4 (Nm3 / h) is 2522.688×7.35×0.01≈185.42; The theoretical power generation capacity of CH4 at 185.42Nm3 / h is 185.42×10=1854.2kW.

[0031] The electrical energy per unit volume of H2 (kW·h / Nm3) is 3; The volume flow rate of H2 (Nm3 / h) is 2522.688×33.02×0.01≈832.99; The theoretical power generation capacity of 832.99 H2 is 832.99×3=2498.97kW.

[0032] Therefore, the theoretical power generation of the tail gas after methanol purge gas hydrogen recovery for 1 hour is: 1496.42+1854.2+2498.97kW=5849.59 kW; If calculated based on the SOFC fuel conversion rate of 60%, the power generation capacity of the tail gas after hydrogen recovery from methanol purge gas for one hour is: 5849.59×0.6=3509.754≈3510kW.

[0033] Carbon emission accounting of this plan: The tail gas flow rate is 2551 kg / h (112.62 kmol / h), of which the carbon-containing substances are CO, CH4, and CO2, and the sum of their proportions (mol%) in the tail gas is: 16.9+7.35+3.79=28.04, assuming that the carbon-containing substances are completely converted into CO2; According to the material balance, the flow rate of CO2 in the flue gas after the reaction is 112.62×28.04×0.01≈31.58 kmol / h; The mass flow rate is 31.58×44=1389.52kg / h, and 1389.52kg of CO2 needs to be captured per hour; According to the calculation of 90% carbon capture efficiency, the CO2 emissions can be reduced per hour as follows: 1389.52×0.9=1250.568≈1251kg.

[0034] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0035] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A solid oxide battery technology and coal chemical coupling system, characterized by: It includes coal chemical industry section, solid oxide fuel cell power generation section and solid oxide electrolysis cell water electrolysis hydrogen production section; The coal chemical industry section includes a coal gasification unit for producing raw coal gas, and the coal chemical industry section also includes a conversion section, a low-temperature methanol washing unit, a methanol synthesis unit, a methanol distillation unit, a methanol storage tank, a refined methanol export unit and a hydrogen recovery unit which are sequentially connected to the output end of the coal gasification unit. A part of the purge gas generated during the synthesis process of the methanol synthesis unit is continuously transported to the methanol synthesis unit as circulating gas to participate in methanol synthesis, another part of the purge gas is recycled through the hydrogen recovery unit to obtain hydrogen-rich gas to be circulated as synthesis gas to synthesize methanol, and another part of the tail gas after hydrogen recovery of the methanol purge gas is used as fuel for the solid oxide fuel cell power generation section; The solid oxide fuel cell power generation section includes a solid oxide fuel cell, a fuel preheater, a burner and a carbon dioxide capture unit. The solid oxide fuel cell includes an anode and a cathode. The tail gas after hydrogen recovery by the hydrogen recovery device is preheated by the fuel preheater and enters the solid oxide fuel cell anode. H2, CO, and CH4 in the tail gas are converted into CO2 and water. The remaining tail gas is burned by the burner and the CO2 in the flue gas is captured and recovered by the carbon dioxide capture unit. The captured CO2 is electrolyzed into CO and O2 by the solid oxide electrolysis cell water electrolysis hydrogen production section. The solid oxide electrolysis cell water electrolysis hydrogen production section comprises a solid oxide electrolysis cell, the solid oxide electrolysis cell comprises a fuel electrode and an air electrode, the solid oxide electrolysis cell generates hydrogen and oxygen by electrolyzing water, wherein the hydrogen enters the conversion section to supplement the hydrogen, and the oxygen enters the coal chemical section as an oxygen source; The system also includes three external supply input units, namely a water supply unit, an air supply unit and a green electricity supply unit, wherein the green electricity generated by the green electricity supply unit electrolyzes water to produce hydrogen and oxygen through the solid oxide electrolysis cell, the water supply unit is used to supply an input water source to the solid oxide electrolysis cell, one path of the air supply unit is connected to the air electrode of the solid oxide electrolysis cell, and the oxygen generated by the air electrode is blown out of the fuel cell stack into the coal chemical section as an oxygen source, and the other path of the air supply unit enters the cathode of the solid oxide fuel cell, and the oxygen in the air and the fuel undergo electrochemical reactions at the anode and cathode of the solid oxide fuel cell to generate electrical energy.

2. A solid oxide battery technology and coal chemical coupling system according to claim 1, characterized in that: The water supply unit comprises a water purifier, a water storage tank, a water pump and a water vapor generator which are connected in sequence.

3. A solid oxide battery technology and coal chemical coupling system according to claim 1, characterized in that: The air supply unit includes a blower, a dryer, a filter and an air preheater which are connected in sequence.

4. A solid oxide battery technology and coal chemical coupling system according to claim 1, characterized in that: The green electricity supply unit is renewable energy power generation, which is at least one of wind power generation, hydropower generation, solar power generation, biomass power generation, ocean power generation, and geothermal power generation.

5. The solid oxide battery technology and coal chemical coupling system according to claim 1, characterized in that: The raw materials of the coal gasification unit are coal powder, water-coal slurry, coal char, water vapor and oxygen from air separation.

6. A method for operating a solid oxide battery technology and coal chemical coupling system, applied to the system according to any one of claims 1 to 5, characterized in that: include: S1, coal chemical industry section: The raw coal gas is produced by using coal powder, water-coal slurry, coal coke, water vapor and oxygen from air separation as raw materials through the coal gasification process; The raw coal gas is converted into hydrogen and carbon dioxide by the reaction of water and carbon monoxide in the conversion stage, and the hydrogen-carbon ratio is adjusted to form raw synthesis gas; The synthesis gas is obtained by removing sulfide and carbon dioxide through a low-temperature methanol washing unit; The carbon monoxide in the synthesis gas reacts with hydrogen through a methanol synthesis unit to produce crude methanol; A methanol distillation device is used to remove water and other organic impurities contained in crude methanol to obtain refined methanol, which is stored in a methanol storage tank and sold externally; Part of the off-gas generated during the synthesis process of the methanol synthesis unit is continuously transported to the methanol synthesis unit as circulating gas to participate in methanol synthesis, another part of the off-gas is recycled through a hydrogen recovery unit to recover hydrogen to obtain hydrogen-rich gas, which is circulated as synthesis gas to synthesize methanol, and another part of the tail gas after hydrogen recovery from the methanol off-gas is used as fuel for the power generation section of the solid oxide fuel cell; S2, Solid Oxide Fuel Cell Power Generation Section: The tail gas recovered from methanol relaxation gas and hydrogen in the coal chemical industry is used as the fuel of the solid oxide fuel cell. The tail gas is preheated by the fuel preheater and enters the solid oxide fuel cell anode to react. The H2, CO, and CH4 in the tail gas are converted into CO2 and water. The remaining tail gas is burned by the burner and the CO2 in the flue gas is captured and recovered by the carbon dioxide capture unit. The captured CO2 is electrolyzed into CO and O2 by the solid oxide electrolysis cell. The air is pressurized by a blower and the moisture in the air is removed by a dryer. The impurities in the air are removed by a filter. The air is preheated by an air preheater and then enters the cathode of the solid oxide fuel cell. The oxygen and fuel in the air undergo an electrochemical reaction at the anode and cathode of the solid oxide fuel cell, causing electron transfer to generate electrical energy. After passing through a DC / DC regulator and inverter, the electrical energy is output and supplied to other electrical equipment. S3, solid oxide electrolysis cell water electrolysis hydrogen production section: Green electricity generated by renewable energy is used to electrolyze water in a solid oxide electrolysis cell to produce hydrogen and oxygen. The hydrogen enters the conversion section to supplement hydrogen and is used to replace the conversion section. The oxygen enters the coal gasification section as an oxygen source to replace the oxygen in the air separation. After being purified by the purifier, the water is stored in a water tank, pressurized by a water pump, and then enters a steam generator to be heated into steam, which then enters the fuel electrode of the solid oxide electrolysis cell to undergo an electrochemical reaction to produce hydrogen. The hydrogen is transported to the conversion section to reduce the scale or eliminate it, and the oxygen ions produced by the fuel electrode pass through the electrolyte to react at the air electrode to produce oxygen. The air is pressurized by a blower, the dryer removes moisture from the air, the filter removes impurities from the air, and after being preheated by an air preheater, it enters the air electrode of the solid oxide electrolysis cell. The oxygen produced by the air electrode is blown out of the fuel cell and enters the coal chemical section as an oxygen source. In addition, water and CO2 are simultaneously electrolyzed in the solid oxide electrolysis cell to prepare synthesis gas as a raw material for methanol synthesis.

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