Carbon-based fuel gasification method and device based on principle of primary cell

Abstract

This invention discloses a carbon-based fuel gasification method based on the principle of a galvanic cell, comprising the following steps: (1) forming a three-layer self-layered structure of a metal layer, a metal oxide layer, and a molten carbonate layer from bottom to top in a reactor; (2) adding carbon-based fuel to the molten carbonate layer; (3) gasification step: forming a galvanic cell with carbon-based fuel as the negative electrode, metal oxide as the positive electrode, and molten carbonate as the electrolyte, wherein the oxygen in the metal oxide is converted into oxygen. 2‑ The form diffuses through the molten carbonate layer to the carbon-based fuel interface, selectively oxidizing the carbon-based fuel to generate CO. The metal oxide is reduced to metal and sinks to the metal layer; (4) Regeneration step: a gaseous oxidant is introduced into the metal layer to oxidize the metal to metal oxide, replenishing the oxygen storage capacity of the metal oxide layer, and completing the storage of oxygen and the circulation of the reaction medium. This invention utilizes the potential of the galvanic cell to spontaneously drive the reaction and manages the gasification process by controlling the "charging / discharging" cycle. It has the advantages of high CO selectivity, good metal oxide volatilization inhibition effect, high fuel impurity tolerance, high gas production calorific value, and spontaneous and efficient reaction, which is suitable for the needs of clean and efficient conversion of distributed carbon-based fuels.

Description

Technical Field

[0001] The technical field of this invention relates to a carbon-based fuel gasification method and apparatus, specifically to a carbon-based fuel gasification method and apparatus based on the principle of a galvanic cell. Background Technology

[0002] With the comprehensive advancement of the "dual-carbon" strategy, building a clean, low-carbon, safe, and efficient energy system has become a major national need. The efficient and clean conversion of carbon-based fuels (such as coal, biomass, and organic waste) is one of the key pathways to achieving energy structure transformation and carbon neutrality goals. Gasification technology can convert these fuels into high-grade syngas (mainly composed of CO and H2), which is the core means to realize their high-value utilization. However, the efficiency and quality of traditional gasification technologies are no longer sufficient to meet the new requirements of distributed and clean utilization, necessitating technological innovation.

[0003] Among existing carbon-based fuel gasification technologies, traditional gasification technologies, such as fixed-bed gasification, fluidized-bed gasification, and entrained gasification, suffer from numerous side reactions and the mixing of gasification media with the produced gas, resulting in high levels of impurities and low calorific value. Furthermore, traditional gasification technologies are often large-scale and difficult to adapt to the dispersed distribution of some carbon-based fuels (such as biomass fuels like straw). Solid-state catalytic gasification technologies, represented by nickel catalysts, are prone to deactivation due to coking and carbon buildup, requiring frequent catalyst replacements and incurring high costs. These problems severely limit the gasification and utilization of carbon-based fuels. Catalytic technologies using liquid metals and molten carbonates as liquid working media, however, offer excellent solid-liquid contact conditions and reaction kinetics, are unaffected by carbon buildup or poisoning of dynamic reaction sites, are easy to operate, and are readily miniaturized. These characteristics make them suitable for the current distribution of carbon-based fuels in my country and hold promise for supporting my country's renewable energy strategy.

[0004] CN105176595B proposes a gasification technology based on the density difference between liquid metal and metal oxides to achieve material recycling, using molten metal as the reaction medium. However, this technology does not include a molten carbonate layer, directly feeding carbon-based fuel into the liquid metal oxide layer.

[0005] CN103289751A and CN101445750A propose a technology for the catalytic gasification of carbon-based compounds using alkali metal molten salts. This technology involves introducing gasifying agents such as oxygen, air, water vapor, and CO2 into the reactor. The heat released from the controlled oxidation of carbon by the gasifying agents in the molten carbonate causes the organic polymers to depolymerize. However, the oxygen supply method in this patent involves directly introducing oxygen-containing gas from the bottom of the device into the molten carbonate.

[0006] CN104941624A proposes a coal catalytic gasification technology that loads alkali metal compounds onto a special support (a variable-valence metal compound containing oxygen defects), which can adsorb oxygen in the gasification medium and convert it into active oxygen, thereby stably forming the key active intermediate MOC in the alkali metal salt, thus efficiently retaining catalytic activity; however, this patent loads compounds of variable-valence metal elements onto alkali metal salts.

[0007] CN101177241A and CN201501787U propose a technology for the partial oxidation of natural gas to produce carbon monoxide and hydrogen using molten carbonate to transfer oxygen to the lattice. Metal oxides are distributed within the molten carbonate, and methane and air are introduced at the bottom of the device for catalytic reforming and recovery of consumed lattice oxygen. However, this patent, by distributing metal oxides within the molten carbonate, cannot guarantee suitable oxygen activity in the reaction zone of the added solid carbon fuel, which is detrimental to the catalytic gasification of solid carbon to produce carbon monoxide.

[0008] Therefore, a new method and apparatus for gasifying carbon-based fuels is needed. Summary of the Invention

[0009] The purpose of this invention is to provide a carbon-based fuel gasification method based on the principle of a galvanic cell. This method organically combines the high ionic conductivity of molten carbonate with the controllable oxygen storage / release capacity of metal oxides to form a spontaneous, "rechargeable" gasification reaction system. This system constructs a "metal-metal oxide" redox pair, which, through its reversible oxidation / reduction reaction, achieves oxygen storage and directional transfer via molten carbonate, driving the entire gasification process spontaneously and efficiently based on the principle of a galvanic cell.

[0010] The technical solution of the present invention is as follows: A carbon-based fuel gasification method based on the principle of a galvanic cell, comprising the following steps: (1) In the reactor, a metal layer, a metal oxide layer, and molten carbon are formed from bottom to top. The acid salt layer has a three-layer self-stratified structure; (2) Add carbon-based fuel to the molten carbonate layer; (3) Gasification step: A galvanic cell is formed with carbon-based fuel as the negative electrode, metal oxide as the positive electrode, and molten carbonate as the electrolyte. The oxygen in the metal oxide is converted into O2. 2- The form diffuses through the molten carbonate layer to the carbon-based fuel interface, selectively oxidizing the carbon-based fuel to generate CO, while the metal oxide is reduced to metal and sinks to the metal layer; (4) Regeneration step: A gaseous oxidant is introduced into the metal layer to oxidize the metal into metal oxide, replenish the oxygen storage capacity of the metal oxide layer, and complete the storage of oxygen and the circulation of the reaction medium. In the gasification step, the positive electrode reaction is 2MOX →2M+xO 2- The negative electrode reaction is C + O 2- →CO; M represents metal / alloy, and x represents the stoichiometric coefficient of oxygen in the metal oxide.

[0011] In the regeneration step, the gaseous oxidant is one or more of air, water vapor, or carbon dioxide, and the corresponding regeneration reactions are: 2M + xO2 → 2MO X M + xH₂O → MO X +xH2, 2M + xCO2 → 2MO X +xCO.

[0012] According to one embodiment of the present invention, the metal / alloy is selected from one or more alloys formed from antimony, cobalt, bismuth, lead, copper, manganese, zinc, iron, tin, cadmium, and vanadium. Preferably, the metal / alloy is an alloy formed from one or more alloys formed from antimony, bismuth, lead, cadmium, and copper. Preferably, the metal is an alloy formed from one or two alloys formed from manganese and iron. Preferably, the metal / alloy is an alloy formed from one or more alloys formed from antimony, vanadium, manganese, and zinc. Preferably, the metal / alloy is an alloy formed from one or two alloys formed from antimony and vanadium.

[0013] According to one embodiment of the present invention, the carbonate is a single / mixed carbonate formed from one or more of lithium carbonate, sodium carbonate, and potassium carbonate. Preferably, the carbonate is a binary carbonate or a ternary carbonate. Preferably, the carbonate is a binary carbonate or a ternary carbonate with high lithium ion content and low potassium ion content. Preferably, the carbonate is a ternary carbonate with high lithium ion content, low potassium ion content, and moderate sodium ion content within the operating temperature range.

[0014] Preferably, the carbon-based fuel is one or more of coal, biomass carbon, carbon black, or organic waste-derived carbon.

[0015] Preferably, the operating temperature inside the reactor is 700-900℃.

[0016] According to one embodiment of the present invention, after the carbon-based fuel reaction is completed, mineral powder with metal oxide as the main component is added to the molten carbonate layer, and the metal oxide in the mineral powder is deposited into the metal oxide layer. Then, carbon-based fuel is added again to reduce the metal oxide to metal.

[0017] A carbon-based fuel gasification device based on the principle of a galvanic cell, comprising a main body of the device and a gasification reaction zone and a regeneration reaction zone disposed within the main body of the device; wherein The gasification reaction zone includes a molten carbonate layer for reacting carbon-based fuels with O2. 2- A reaction occurs, selectively oxidizing carbon-based fuels to CO, while metal oxides are reduced to metals; The regeneration reaction zone includes a metal layer for introducing a gaseous oxidant to oxidize the metal into a metal oxide. A metal oxide layer is provided between the molten carbonate layer and the metal layer, thereby forming a metal layer, a metal oxide layer and a molten carbonate layer from bottom to top inside the main body of the device.

[0018] According to one embodiment of the present invention, the main body of the device is provided with a feed inlet, an air inlet, and an air outlet, wherein the feed inlet is located in the gasification reaction zone and is connected to the molten carbonate layer, and the air inlet is located in the regeneration reaction zone and is connected to the metal layer. Preferably, the parts of the main body of the device that are in contact with the molten carbonate layer, the metal layer, and the metal oxide layer are made of ceramic material, and the exterior of the main body of the device is made of stainless steel material.

[0019] Preferably, the liquid level at the gas outlet is lower than the molten carbonate layer.

[0020] The technical solution of the present invention has the following advantages: (1) The present invention utilizes the potential of the galvanic cell to spontaneously drive the reaction and manages the gasification process by controlling the “charging / discharging” cycle.

[0021] (2) Compared with conventional liquid metal catalytic systems, the carbon monoxide selectivity in this invention is high. Molten carbonate is a good ionic conductor, especially with high ionic conductivity at high temperatures. Adding a molten carbonate layer over the metal layer and metal oxide layer can isolate the gas from contact with the metal oxide and allow oxygen to be transferred quickly and efficiently from the metal oxide layer to the carbon-based fuel interface through the molten carbonate layer, providing suitable oxygen activity for the carbon-based fuel. This constitutes a galvanic cell system with carbon fuel as the negative electrode, metal oxide as the positive electrode, and molten carbonate as the electrolyte, promoting the gasification reaction. Molten carbonate can also promote the Boudouard reaction (C + CO2 → 2CO), further improving carbon monoxide selectivity and inhibiting tar formation, which is beneficial for the subsequent utilization of the gas. (3) At the same temperature, the higher the saturated vapor pressure of a liquid, the easier it is for its molecules to leave the liquid phase and enter the gas phase, and the stronger its volatility. Molten carbonates are ionic compounds with saturated vapor pressures significantly lower than those of liquid metal oxides. Therefore, coating the metal oxide with a layer of molten carbonate can effectively suppress volatilization.

[0022] (4) Molten carbonates have high solubility for ash such as NaCl, CaCO3, CaSO4, alkali and alkaline earth metals in carbon-based fuels. Compared with non-molten salt systems, during the gasification process of molten carbonates, the ash contained in carbon-based fuels will gradually seep into the molten carbonates, preventing metal oxides from being contaminated by ash and reducing the inhibitory effect of ash on gasification reactivity.

[0023] (5) The present invention adopts a special device structure to realize the spatial isolation between the gasification reaction zone and the regeneration reaction zone. Through the path of "oxygen in gaseous oxidant → metal oxide → oxygen transferred in molten carbonate → carbon-based fuel", it realizes limited oxygen supply and selective oxidation based on the oxygen storage capacity of metal oxide and the oxygen conductor characteristics of molten carbonate. It avoids the dilution and pollution of gas produced by the gasification medium, ensures gas quality and high calorific value, and reduces costs because cheap oxidants such as air can be used directly instead of pure oxygen as oxygen source.

[0024] (6) In this invention, molten carbonate is used as an oxygen ion conductor. On the one hand, the original carbon-based fuel-metal oxide reaction interface is decomposed into two interfaces: fuel-molten salt and molten salt-metal oxide. Such solid-liquid interface has better contact and can be used for more complex solid carbon-based fuels, as well as gaseous or liquid carbon-based fuels. After being decomposed into two reaction interfaces, the oxygen activity of the carbon-based fuel oxidation reaction interface can be regulated. Furthermore, by regulating the oxygen activity of the carbon-based fuel oxidation interface, the product can be shifted towards the effective partial oxidation product (H2 / CO), thereby improving the gas production efficiency. Moreover, the regulation space also makes the range of selectable metals / alloys wider. Attached Figure Description

[0025] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0026] Figure 1 This is a schematic diagram of a carbon-based fuel gasification device based on the principle of a galvanic cell, according to an embodiment of the present invention. Figure 2 This is a synthesis gas chromatography spectrum prepared according to an embodiment of the present invention for a carbon-based fuel gasification method based on the principle of a galvanic cell. Detailed Implementation

[0027] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] The carbon-based fuel gasification method based on the principle of a galvanic cell described in this invention is based on a stable three-layer structure: from bottom to top, a metal layer, a metal oxide layer serving as an oxygen storage medium, and a molten carbonate layer, essentially constituting a recyclable, self-discharge galvanic cell gasification system. Its operation consists of two core steps: Gasification step (i.e., the discharge process of a galvanic cell): After carbon-based fuel is added to the top layer of molten carbonate, a galvanic cell is formed: the carbon-based fuel is the negative electrode, the metal oxide is the positive electrode, and the molten carbonate is the electrolyte. Oxygen stored in the metal oxide diffuses to the carbon-based fuel interface through the molten carbonate layer, providing suitable oxygen activity for the reaction interface of the carbon-based fuel, and selectively oxidizing it to carbon monoxide. The metal oxide is then reduced to metal due to the loss of oxygen. This process is the "discharge" process of the galvanic cell, converting the chemical energy in the carbon fuel and metal oxide into the chemical and thermal energy in the syngas.

[0029] The regeneration step (i.e., the charging process of the primary battery) involves introducing a gaseous oxidant such as air, water vapor, or carbon dioxide into the bottom metal layer. This oxidizes the metal to form metal oxides, replenishing the consumed metal oxide layer and completing the storage of oxygen and the circulation of the reaction medium. This process "charges" the gasification system, restoring the oxygen storage capacity of the metal oxide layer.

[0030] This gasification system utilizes a molten carbonate layer as an oxygen transport channel and reaction medium, and leverages the oxygen storage and release characteristics of metal oxides to achieve highly selective oxidation and gasification of carbon through a galvanic cell principle. The flowing characteristics of the molten carbonate layer continuously expose effective reaction sites, preventing reaction termination due to coking and carbon buildup.

[0031] The reaction equation for the gasification process (discharge process) is as follows: Positive electrode reaction: 2MOx → 2M + xO 2- Negative electrode reaction: C + O 2- →CO The reaction equation for the regeneration process (charging process) is: 2M + xO2 → 2MO X (The oxidizing agent is air) M + xH₂O → MO X + xH2 (Oxidizing agent is water vapor) 2M + xCO2 → 2MO X +xCO (Oxidizing agent is carbon dioxide) Where M represents the metal / alloy, and x represents the stoichiometric coefficient of oxygen in the metal oxide. The metal or alloy can be selected from one or more alloys formed from antimony, cobalt, bismuth, lead, copper, manganese, zinc, iron, tin, cadmium, and vanadium. The metal / alloy and its corresponding metal oxide can be reduced by carbon-based fuel within the operating temperature range. The metal / alloy can be oxidized by a gaseous oxidant, ensuring the reaction is a spontaneous process. The carbon-based fuel, molten carbonate, and metal oxide serve as the negative electrode, electrolyte, and positive electrode of the galvanic cell, respectively, forming a self-discharge galvanic cell, which facilitates faster reaction. Further, under the above conditions, a metal or alloy with a more negative Gibbs free energy at the operating temperature for the reaction of the corresponding metal oxide with carbon to produce carbon monoxide can be selected, such as antimony, manganese, zinc, or antimony-manganese alloys. According to the formula... The more negative the Gibbs free energy, the greater the theoretical voltage of the galvanic cell, the greater the driving force for the directional migration of oxygen through the molten carbonate electrolyte, thus achieving highly selective oxidation of carbon and a faster reaction rate.

[0032] Furthermore, the present invention may employ liquid metal / alloy or metal oxide, or solid metal / alloy or metal oxide, or one of the metal / alloy or metal oxide may be solid and the other liquid.

[0033] According to a specific embodiment of the present invention, when the selected metal or alloy and the corresponding metal oxide are both in a liquid state within the operating temperature range, the contact between the molten carbonate layer and the metal oxide layer is a liquid-liquid contact, and the interfacial impedance of this liquid-liquid contact interface is lower than that of a solid-liquid or solid-solid contact interface. During the vaporization and regeneration processes of the metal or alloy, both the metal and the metal oxide are in a liquid state, forming a liquid self-circulating redox pair. Through natural convection, they quickly leave the vaporization interface and the oxidation interface, thereby maintaining the continuous progress of the reaction. Further, under the above conditions, the density of the metal or alloy can be greater than the density of the corresponding metal oxide. Preferably, the metal or alloy can be selected from one or more of antimony, vanadium, and antimony-vanadium alloys. Since the density of the metal oxide is lower than that of the corresponding metal or alloy, when it is reduced to a metal or alloy, the high-density metal or alloy can be promptly removed from the reaction zone; conversely, when the metal or alloy is oxidized to generate a metal oxide, the low-density metal oxide can promptly return to the reaction zone. The density difference-driven natural convection achieves automatic separation and circulation of reactants and products, thereby forming a stable cycle.

[0034] According to a specific embodiment of the present invention, when the selected metal or alloy and its corresponding metal oxide are both solid within the operating temperature range, or when one of the metal / alloy or metal oxide is solid and the other is liquid, a metal with a loose oxide film that is easily penetrated by molten carbonate, such as iron, should be selected. In this state, a liquid-solid interface is formed between the molten carbonate and the metal oxide, and its interfacial resistance is higher than that of the liquid-liquid interface, which can ensure that the reaction between the molten carbonate and the metal oxide continues.

[0035] According to a specific embodiment of the present invention, a metal or alloy with high conductivity corresponding to the metal oxide can be selected, such as antimony, vanadium, manganese, zinc, antimony-vanadium alloy, antimony-nickel alloy, etc. The metal oxide layer should have good conductivity to promote charge transport inside the galvanic cell. If the conductivity of the metal oxide layer is insufficient, it will lead to an increase in the internal resistance of the galvanic cell, thereby reducing the voltage efficiency.

[0036] According to a specific embodiment of the present invention, the selected metal or alloy can have a density and electrical conductivity greater than that of the corresponding metal oxide. Within the operating temperature range of the device, the metal / alloy or metal oxide is in a liquid state and can be reduced by carbon-based fuel. At the same time, the Gibbs free energy of the reaction to generate carbon monoxide is more negative. For example, antimony, bismuth, lead, cadmium, copper, etc., because the reaction kinetics of liquid-liquid contact are better than those of solid-liquid contact, and the reaction and mass transfer effects are better.

[0037] According to a specific embodiment of the present invention, when liquid metal / alloy or metal oxide is selected as the oxygen storage medium, since the density of molten carbonate is low, according to the principle of communicating vessels, the liquid level at the outlet can be lower than the molten carbonate layer; at the same time, it is convenient to take samples and detect at the outlet.

[0038] According to another specific embodiment of the present invention, when using solid metal / alloy or metal oxide as the oxygen storage medium, the metal or metal oxide can first be processed into fine metal or metal oxide particles with small particle size. This increases the specific surface area of ​​the particles, improves mass transfer efficiency, and provides sufficient reaction sites for gas-solid interactions during the oxygen storage process. Then, a gaseous oxidant is continuously introduced from the bottom of the device. Using the kinetic energy of the gaseous oxidant flow, the fine particles in the ventilation area are placed in a suspended, mixed, fluidized state, allowing the gaseous oxidant to fully contact and react with the particles, ultimately completing the oxygen storage process.

[0039] The molten carbonate can be a single or mixed carbonate formed from one or more of lithium carbonate, sodium carbonate, and potassium carbonate.

[0040] According to one embodiment of the present invention, single or mixed carbonates with melting points lower than the operating temperature can be selected, such as binary carbonates Li-Na, Li-K, and Na-K mixed salts, or ternary carbonates Li-Na-K mixed salts. Compared to single-component carbonates, binary or ternary carbonates typically have lower melting points, and only carbonates in the molten state can act as ionic conductors and have good contact with solid carbon-based fuels and metal oxides.

[0041] According to one embodiment of the present invention, the selected carbonate can have high ionic conductivity within the operating temperature range. Lithium ions have the highest mobility due to their smallest ionic radius, while potassium ions have a larger ionic radius, which enhances the electrostatic interaction between ions and reduces their mobility. Therefore, carbonates with high lithium ion content and low potassium ion content can be selected to improve ionic conductivity. Molten carbonates act as ionic conductors, and selecting carbonates with high ionic conductivity is beneficial for ion transfer in galvanic cell reactions, thereby increasing the reaction rate; where S is the unit of ionic conductivity.

[0042] According to one embodiment of the present invention, the selected carbonate can have low solubility for metal oxides (such as antimony oxide) that meet the specified conditions. The main influencing factors on the solubility of metal oxides are the acidity / alkalinity of the carbonate and the partial pressure of carbon dioxide. Since no gasifying agent such as carbon dioxide is mixed in the gasification zone where the molten carbonate is located in this device, the dissolution of metal oxides is mainly alkaline. Therefore, selecting a carbonate with lower alkalinity can minimize the solubility of metal oxides, which is beneficial to the long-term stable operation of the device.

[0043] According to one embodiment of the present invention, the selected carbonate can possess a certain degree of thermal stability at the operating temperature, such as a ternary mixed carbonate. Because molten carbonates with different proportions exhibit different thermal stability, ternary mixed carbonates, with their relatively high potassium and sodium content, generally possess higher thermal stability. Therefore, selecting a carbonate proportion that matches the operating temperature and possesses thermal stability can prevent material loss and is of great significance for the normal progress of the gasification reaction.

[0044] According to one embodiment of the present invention, the selected carbonate has low corrosivity to the reactor body or pipelines, and can promote the formation of a stable, dense, and protective oxide film on the material surface, which is beneficial to the long-term stable operation of the device. Specifically, at a suitable operating temperature, a ternary molten carbonate with high lithium, low potassium, and moderate sodium content can be selected, because corrosivity is not simply determined by pH, but is closely related to the dissolution-redeposition mechanism of the oxide film by the molten salt composition.

[0045] According to one embodiment of the present invention, the carbon-based fuel can be solid, gaseous or liquid. For example, the carbon-based fuel can be one or more of coal, biomass carbon, carbon black or organic waste-derived carbon; the carbon-based fuel can also be natural gas or methanol, etc.

[0046] According to an embodiment of the present invention, the carbon-based fuel gasification method based on the principle of a galvanic cell can also be combined with a metallurgical process. The specific steps are as follows: after the carbon-based fuel reaction is completed, mineral powder with metal oxides as the main component is added to the molten carbonate layer. The metal oxides in the mineral powder are deposited into the metal oxide layer, and at this time, impurities are dissolved by the molten carbonate. Then, carbon-based fuel is added again to reduce the metal oxides to metal, thereby completing the combination of metallurgy and galvanic cell charging and discharging.

[0047] Based on the above, such as Figure 1 As shown, an embodiment of the present invention also provides a carbon-based fuel gasification device 10 based on the principle of a galvanic cell. The device 10 includes a device body 11, a feed inlet 12, a slag discharge outlet 13, an air inlet 14, and an air outlet 15 disposed on the device body 11. Inside the device 10, a metal layer 16, a metal oxide layer 17, and a molten carbonate layer 18 are formed from bottom to top. The air inlet 14 is connected to the metal layer 16 and is located at the bottom of the device body, allowing for continuous introduction of oxidant while feeding. The feed inlet 12 is connected to the molten carbonate layer 18 and is located at the top of the device body, for adding carbon-based fuel 19 to the molten carbonate layer 18. The slag discharge outlet 13 is located in the molten carbonate layer area for discharging slag. The air outlet 15 is located at the top of the device body for collecting syngas. An exhaust port 20 is also provided in the metal oxide layer for discharging excess gas.

[0048] According to a specific embodiment of the present invention, the lower part of the gas outlet 15 can be an inclined structure, which can promote the enrichment and discharge of excess gaseous oxidant, prevent the oxidant from entering the left gas production area, and thus prevent the product gas from being contaminated.

[0049] After prolonged operation, the molten carbonate layer of the device 10 can physically isolate harmful impurities in carbon-based fuels and prevent contamination by metal oxides and metals / alloys. However, the molten carbonate layer itself can accumulate impurities contained in the carbon-based fuel, such as alkali metal salts, silicon-aluminum compounds, chlorides, and sulfides. These impurities may increase the viscosity of the molten salt, affecting its fluidity and ion transport; this also leads to the corrosiveness of the molten carbonate to the tank, causing equipment damage. Therefore, it is necessary to periodically add a slagging agent to the molten carbonate layer through the feed inlet and discharge the slag through the discharge outlet. The slagging agent can be limestone, magnesium oxide, copper slag, or other slagging agents that can remove the aforementioned impurities.

[0050] According to a specific embodiment of the present invention, the slag discharge port 13 may be provided with a slag scraper, which may be made of a high-temperature resistant material, such as ceramic material, for removing floating slag.

[0051] The air outlet can be a long and narrow structure, which facilitates sampling and testing at the air outlet to assess the state of the metal inside the device.

[0052] The operating temperature within the device can be between 700-900℃, depending on the melting point of the metals, metal oxides, and molten carbonates inside the device. Excessively high operating temperatures will increase the difficulty of thermal management and material selection during device operation.

[0053] During the reaction, the gaseous oxidant can be supplied continuously or intermittently.

[0054] Since the interior of the device body 11 comes into contact with liquid metal, liquid metal oxides, and molten carbonates, it can be made of materials resistant to high-temperature molten salt and liquid metal corrosion, such as alumina ceramics and silicon nitride ceramics. The exterior of the device body, which requires heating, can be made of high-temperature resistant stainless steel, such as SUS430 or 316L, to provide structural support and sealing.

[0055] To further illustrate the carbon-based fuel gasification method and apparatus based on the galvanic cell principle provided in the embodiments of the present invention, specific embodiments are described below. Example 1

[0056] In this embodiment, using Figure 1 The gasification apparatus shown uses antimony as the metallic medium and biomass carbon as the raw material. It does not introduce an additional gaseous oxidant and utilizes molten carbonate to conduct oxygen for gasification, producing syngas. The specific gasification method is as follows: (1) In the main body of the device, add metallic antimony, antimony trioxide and a mixture of potassium carbonate and sodium carbonate in a molar ratio of 1:1 in sequence.

[0057] (2) The internal temperature of the main body of the device is raised to 850°C using a tube furnace and kept at that temperature to ensure that each layer is in a molten state and forms a stable liquid three-layer structure: the bottom layer is molten antimony, the middle layer is molten antimony trioxide, and the top layer is molten carbonate.

[0058] (3) Biomass carbon is added to the molten carbonate layer through the feed inlet.

[0059] (4) Gasification step: Oxygen in the molten antimony trioxide layer diffuses through the molten carbonate layer and reacts with biomass carbon to oxidize it into syngas, which is mainly composed of carbon monoxide; antimony trioxide is reduced to metallic antimony and sinks to the bottom layer.

[0060] (6) Collect the syngas produced during the reaction and analyze its components using a mass spectrometer.

[0061] Gas production was measured by mass spectrometry; the CO peak area between 1500 s and 1600 s was 1.3903 × 10⁻⁶. -8 The CO2 peak area between 1500s and 1600s is 2.5362 × 10⁻¹⁰. -9 ,like Figure 2 As shown, the CO selectivity was calculated to be 84% by the ratio of peak area to peak area. This embodiment utilizes the density difference between antimony and antimony trioxide as the driving force, combined with the oxygen conduction and covering effect of the molten carbonate layer, to achieve self-circulation and highly selective gasification of materials in the furnace. Example 2

[0062] The gasification method and apparatus are basically the same as in Example 1, and the raw materials used are as follows: carbon-based fuel is carbon black, the positive electrode is solid iron oxide, the molten carbonate as electrolyte is a mixture of sodium carbonate and potassium carbonate in a molar ratio of 1:3, and the metal layer is iron; the operating temperature is 850℃, and a gaseous oxidant is introduced during the reaction. The syngas produced by the reaction is analyzed by mass spectrometry, and the composition is shown in Table 1. Example 3

[0063] The gasification method and apparatus are the same as in Example 1, and the raw materials used are as follows: the carbon-based fuel is biomass carbon, the positive electrode is liquid antimony oxide, the molten carbonate as the electrolyte is a 1:1 molar ratio of sodium carbonate and potassium carbonate mixed salt, and the metal layer is antimony; the operating temperature is 800℃. The syngas produced by the reaction was analyzed by mass spectrometry, and the composition is shown in Table 1. Example 4

[0064] The gasification method and apparatus are basically the same as in Example 1, and the raw materials used are as follows: the carbon-based fuel is biomass carbon, the positive electrode is liquid vanadium pentoxide, the molten carbonate as the electrolyte is a 1:1 molar ratio mixture of sodium carbonate and potassium carbonate, and the metal layer is vanadium; the operating temperature is 800℃, and a gaseous oxidant is introduced during the reaction. The syngas produced by the reaction is analyzed by mass spectrometry, and the composition is shown in Table 1. Example 5

[0065] The gasification method and apparatus are the same as in Example 1, and the raw materials used are as follows: the carbon-based fuel is coal, the positive electrode is liquid antimony oxide, the molten carbonate as the electrolyte is a mixed salt of lithium carbonate, sodium carbonate, and potassium carbonate in a molar ratio of 5:3:2, and the metal layer is antimony; the operating temperature is 850℃. The syngas produced by the reaction was analyzed by mass spectrometry, and the composition is shown in Table 1. Example 6

[0066] The gasification method and apparatus are the same as in Example 1, and the raw materials used are as follows: the carbon-based fuel is coal, the positive electrode is solid iron oxide, the molten carbonate as the electrolyte is a mixed salt of lithium carbonate, sodium carbonate, and potassium carbonate in a molar ratio of 5:3:2, and the metal layer is iron; the operating temperature is 800℃. The syngas produced by the reaction was analyzed by mass spectrometry, and the composition is shown in Table 1.

[0067] Table 1

[0068] As can be seen from Table 1, the synthesis gas produced by the carbon-based fuel gasification method and apparatus based on the galvanic cell principle according to the present invention has high selectivity for carbon monoxide, fast gas production rate, and a greater gas production of molten carbonate per unit time and unit volume.

[0069] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method for gasifying carbon-based fuels based on the principle of a galvanic cell, characterized in that, Includes the following steps: (1) In the reactor, a metal layer, a metal oxide layer, and molten carbon are formed from bottom to top. The acid salt layer has a three-layer self-layered structure; (2) Add carbon-based fuel to the molten carbonate layer; (3) Gasification step: A galvanic cell is formed with carbon-based fuel as the negative electrode, metal oxide as the positive electrode, and molten carbonate as the electrolyte. The oxygen in the metal oxide is converted into O2. 2- The form diffuses through the molten carbonate layer to the carbon-based fuel interface, selectively oxidizing the carbon-based fuel to generate CO, while the metal oxide is reduced to metal and sinks to the metal layer; (4) Regeneration step: A gaseous oxidant is introduced into the metal layer to oxidize the metal into metal oxide, replenish the oxygen storage capacity of the metal oxide layer, and complete the storage of oxygen and the circulation of the reaction medium.

2. The gasification method according to claim 1, characterized in that, In the gasification step, the positive electrode reaction is 2MO X →2M+xO 2- The negative electrode reaction is C + O 2- →CO; M represents metal / alloy, and x represents the stoichiometric coefficient of oxygen in the metal oxide.

3. The gasification method according to claim 1, characterized in that, In the regeneration step, the gaseous oxidant is one or more of air, water vapor, or carbon dioxide, and the corresponding regeneration reactions are: 2M + xO2 → 2MO X M + xH₂O → MO X +xH2, 2M + xCO2 → 2MO X +xCO.

4. The gasification method according to claim 1, 2, or 3, characterized in that, The metal / alloy is selected from one or more of antimony, cobalt, bismuth, lead, copper, manganese, zinc, iron, tin, cadmium, and vanadium to form an alloy.

5. The gasification method according to claim 4, characterized in that, The metal / alloy is an alloy formed from one or more of antimony, bismuth, lead, cadmium, and copper.

6. The gasification method according to claim 4, characterized in that, The metal is an alloy formed from one or two of manganese and iron.

7. The gasification method according to claim 4, characterized in that, The metal / alloy is an alloy formed from one or more of antimony, vanadium, manganese, and zinc; preferably, the metal / alloy is an alloy formed from one or two of antimony and vanadium.

8. The gasification method according to any one of claims 1-7, characterized in that, The carbonate is a single carbonate or a mixed carbonate formed from one or more of lithium carbonate, sodium carbonate, and potassium carbonate.

9. The gasification method according to claim 8, characterized in that, The carbonate is a binary carbonate or a ternary carbonate; preferably, the carbonate is a binary carbonate or a ternary carbonate with high lithium ion content and low potassium ion content; preferably, the carbonate is a ternary carbonate with high lithium ion content, low potassium ion content, and moderate sodium ion content within the operating temperature range.

10. The gasification method according to any one of claims 1-9, characterized in that, The carbon-based fuel is one or more of coal, biomass carbon, carbon black, or carbon derived from organic waste.

11. The gasification method according to any one of claims 1-10, characterized in that, The operating temperature inside the reactor is 700-900℃.

12. The gasification method according to any one of claims 1-11, characterized in that, After the carbon-based fuel reaction is complete, mineral powder, mainly composed of metal oxides, is added to the molten carbonate layer. The metal oxides in the mineral powder are deposited into the metal oxide layer. Then, carbon-based fuel is added again to reduce the metal oxides to metal.

13. A carbon-based fuel gasification device based on the galvanic cell principle as described in any one of claims 1-12, characterized in that, It includes the main body of the device and the gasification reaction zone and regeneration reaction zone located inside the main body of the device; wherein The gasification reaction zone includes a molten carbonate layer for reacting carbon-based fuels with O2. 2- A reaction occurs, selectively oxidizing carbon-based fuels to CO, while metal oxides are reduced to metals; The regeneration reaction zone includes a metal layer for introducing a gaseous oxidant to oxidize the metal into a metal oxide. A metal oxide layer is provided between the molten carbonate layer and the metal layer, thereby forming a metal layer, a metal oxide layer and a molten carbonate layer from bottom to top inside the main body of the device.

14. The gasification apparatus according to claim 13, characterized in that, The main body of the device is provided with a feed inlet, an air inlet and an air outlet, wherein the feed inlet is located in the gasification reaction zone and is connected to the molten carbonate layer, and the air inlet is located in the regeneration reaction zone and is connected to the metal layer.

15. The gasification apparatus according to claims 13 and 14, characterized in that, The part of the device body that comes into contact with the molten carbonate layer, the metal layer, and the metal oxide layer is made of ceramic material, while the exterior of the device body is made of stainless steel.

16. The gasification apparatus according to any one of claims 13-15, characterized in that, The liquid level at the outlet is lower than the molten carbonate layer.

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