A fuel autothermal reforming reaction system and method suitable for extreme combustion conditions

Abstract

The present invention discloses a fuel autothermal reforming reaction system and method suitable for use under extreme combustion conditions. The system includes a pipeline flow subsystem, an electric preheater, a reforming reactor, and a waste heat recovery heat exchanger. The pipeline flow subsystem mixes the reaction gas and reforming fuel in appropriate proportions and then feeds them to the electric preheater or waste heat recovery heat exchanger. The electric preheater heats the reaction gas during a cold start of the system. The reforming reactor couples the exothermic heat of the reaction gas from porous medium combustion with the heat absorbed by the reforming fuel. The waste heat recovery heat exchanger recovers the waste heat of the high-temperature flue gas and reforming products discharged from the reforming reactor into the reaction gas and reforming fuel to be burned after the cold start. This solution, through preheating and porous medium combustion technology, expands the range of fuels applicable to the fuel autothermal reforming reaction system to include fuels that are difficult to burn, facilitating the development and utilization of new fuels (such as ammonia) and low-calorific-value, dilute fuels (such as low-concentration gas).

Description

Technical Field

[0001] The present invention relates to the technical field of autothermal reforming reactions, and in particular to a fuel autothermal reforming reaction system and method suitable for use under extreme combustion conditions. Background Art

[0002] Fuel combustion accounts for over 80% of energy conversion. To protect the environment and improve energy efficiency, achieving clean, efficient fuel combustion and regulation is a key issue. Fuel reforming can crack and restructure the parent fuel, producing a variety of small molecule fuels with varying combustion activities. By fully or partially reforming the fuel, the combustion process can be effectively regulated to meet the fuel combustion and emission performance requirements of actual combustion equipment.

[0003] Fuel reforming is a typical endothermic process. According to the source of the absorbed heat, reforming technology can be divided into autothermal reforming and reforming with external heat source. Among them, autothermal reforming has attracted attention due to its advantages of not requiring an external heat source, compact reactor structure, and fast startup response.

[0004] Autothermal reforming technology can adopt two operating modes. The first is to use the heat released by partial combustion and oxidation of the fuel to reform the surplus fuel. In this mode, fuel reforming and combustion are in the same space, and the reformed gas is in a relatively rich combustion condition. In order to improve the reforming energy efficiency of the system (reforming more fuel when burning a unit mass of fuel), it is necessary to increase the equivalence ratio (the ratio of fuel to oxidant) of the reformed gas as much as possible to the rich side (equivalence ratio greater than 1, with surplus fuel). However, under large equivalence ratio conditions, fuel combustion stability problems often occur, and may even directly lead to flameout and failure of the reforming system. The second operating mode is to separate fuel combustion and reforming in different spaces using a partitioned wall reactor. The equivalence ratio of the reaction gas (a mixture of fuel and oxidant) in the combustion chamber is equal to or less than 1, while the reforming chamber is pure fuel. The reforming reaction is carried out by absorbing the heat released in the combustion chamber. Although the second operating mode has a more complex reformer structure, it can effectively avoid the combustion instability problem that may exist under the first operating mode when the concentration of effective components in the reforming product is low and the extremely rich fuel conditions are extremely high, reducing the separation cost of the reforming product and having higher operational flexibility. However, when burning low-concentration combustible gas (such as low-concentration methane) or difficult-to-burn gas (such as ammonia), the combustion chamber also faces combustion stability problems.

[0005] With the continuous advancement and development of energy research worldwide, concerns about global warming have driven the development of fuels towards low-carbon or even zero-carbon energy. Hydrogen is the ideal zero-carbon fuel, but safety issues in its storage and transportation have significantly hindered its large-scale application. Currently, ammonia is considered a highly promising clean fuel due to its mature production and storage and transportation technologies, high mass energy density, and zero-carbon properties (complete combustion produces only water and nitrogen). Ammonia's inherent physicochemical properties determine its narrow flammability limits, high minimum ignition energy, unstable flames, and slow flame propagation. However, partial reforming of ammonia produces highly combustible hydrogen, effectively addressing the inherent combustion characteristics of ammonia.

[0006] Fuel autothermal reforming technology is currently mostly used for hydrogen production from reforming of large molecular fuels, such as high-carbon hydrocarbons and alcohols, and the fuels used are all flammable conventional fossil fuels. However, mobile fuel autothermal reforming reactors that are suitable for burning difficult-to-burn ammonia or low-concentration combustible gases (such as low-concentration gas) and can operate under extreme combustion conditions still need to be developed and promoted. Summary of the Invention

[0007] In view of the above-mentioned deficiencies in the prior art, the technical problem to be solved by the present invention is: how to provide a fuel autothermal reforming reaction system and method suitable for ammonia or low-concentration combustible gas that is difficult to burn and can operate under extreme combustion conditions.

[0008] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0009] A fuel autothermal reforming reaction system suitable for extreme combustion conditions, comprising a pipeline flow subsystem, an electric preheater, a reforming reactor, and a waste heat recovery heat exchanger;

[0010] The pipeline flow channel subsystem is connected to the electric heating preheater and the waste heat recovery heat exchanger respectively. The pipeline flow channel subsystem proportions and fully mixes the reaction gas and then delivers it to the electric heating preheater or the waste heat recovery heat exchanger, and proportions the reforming fuel and then delivers it to the waste heat recovery heat exchanger;

[0011] The electric preheater is connected to the reforming reactor, and is used to heat the reaction gas when the system is cold started, and to deliver the heated reaction gas to the reforming reactor;

[0012] The reforming reactor is connected to the waste heat exchanger. The reforming reactor is used to achieve the coupling of the exothermic heat of the porous medium combustion of the reaction gas and the heat absorption of the reforming fuel. The reaction gas releases heat in the form of porous medium combustion, and the heat released by the combustion of the reaction gas is absorbed by the reforming fuel. The reforming reactor transports the high-temperature flue gas generated by the combustion of the reaction gas and the reforming products formed after the reforming of the reforming fuel to the waste heat recovery heat exchanger.

[0013] The waste heat recovery heat exchanger is used to recover the waste heat of the high-temperature flue gas and reformed products discharged from the reforming reactor. Through convection and heat conduction heat exchange, the waste heat of the high-temperature flue gas and reformed products is recovered into the reaction gas to be burned and the fuel to be reformed after cold start, and the heated reaction gas to be burned and the fuel to be reformed are transported to the reforming reactor.

[0014] In this way, when the fuel autothermal reforming reaction system of this scheme is working, at the initial cold start of the system, the pipeline flow channel subsystem will separately proportion the reaction gas (a mixture of fuel and oxidant) to be burned and the reforming fuel to be reformed, wherein the reaction gas to be burned is transported to the electric heating preheater, which can achieve the preheating effect of the reaction gas. The preheated reaction gas then enters the reforming reactor for porous medium combustion, and the reforming fuel is transported to the reforming reactor through the waste heat recovery heat exchanger. The reaction gas and the reforming fuel are coupled in the reforming reactor to release heat through the porous medium combustion of the reaction gas and absorb heat through the reforming of the reforming fuel. Most of the heat released by the reaction gas in the porous medium combustion mode will be absorbed by the reforming fuel, and the high-temperature flue gas generated by the combustion of the reaction gas and the reformed products of the reforming fuel will be further transported to the waste heat recovery heat exchanger, and the waste heat recovery heat exchanger will recover the waste heat of the high-temperature flue gas and the reformed products.

[0015] When the system is started for a period of time, after the reaction gas forms a stable porous medium combustion in the reforming reactor, the electric heating preheater is turned off. At this time, the reaction gas is gradually transported to the waste heat recovery heat exchanger. When the temperature of the electric heater drops to a low temperature, all the reaction gas is transported to the waste heat recovery heat exchanger. The reaction gas to be burned and the fuel to be reformed transported to the waste heat recovery heat exchanger absorb heat from the high-temperature flue gas and the waste heat of the reforming product through convection and heat conduction. After heating, the reaction gas to be burned and the fuel to be reformed are then transported to the reforming reactor.

[0016] Therefore, before the reaction gas of this scheme enters the reforming reactor for combustion, it is preheated in advance through an electric heating preheater or a waste heat recovery heat exchanger, thereby initially extending its flammability limit. The reaction gas entering the reforming reactor is then subjected to porous medium combustion, and the stable combustion characteristics of the porous medium during combustion can be used to further extend its flammability limit. At the same time, the reforming fuel can also absorb heat in the waste heat recovery heat exchanger, thereby improving the reforming effect of the reforming fuel. In summary, this scheme utilizes the combination of preheating and porous medium combustion to achieve autothermal reforming reactions of ammonia or low-concentration combustible gases that are difficult to burn, or fuels operating under extreme combustion conditions.

[0017] Preferably, the reforming reactor includes a thermoelectric subsystem, which absorbs part of the heat released by the combustion of the reaction gas and converts this heat into electrical energy through thermoelectric power generation and stores it in a battery. The battery is used to supply power to the fuel autothermal reforming reaction system.

[0018] Preferably, the fuel autothermal reforming reaction system further includes a product collection and storage subsystem and a flue gas treatment device;

[0019] The product collection and storage subsystem is connected to the waste heat recovery heat exchanger and is used to store the reformed product after waste heat recovery after concentration and separation or directly store it;

[0020] The flue gas treatment device is connected to the waste heat recovery heat exchanger and is used to treat pollutants in the flue gas after waste heat recovery.

[0021] Preferably, the pipeline flow channel subsystem includes a gas source, a gas mass flow controller and a gas mixer connected in sequence;

[0022] The gas source is used to provide fuel, oxidant gas and reforming fuel;

[0023] The gas mass flow controller is used to supply the fuel, oxidant gas and reformed fuel in a quantitative proportion as needed, and deliver the proportioned fuel and oxidant to the gas mixer, and deliver the proportioned reformed fuel to the waste heat recovery heat exchanger;

[0024] The gas mixer is used to fully mix the fuel and oxidant after proportioning to form a reaction gas, and to transport the reaction gas to the electric heating preheater or the waste heat recovery heat exchanger.

[0025] Preferably, the electric heating preheater includes a preheater body, a preheating chamber is provided in the preheater body, an electric heating wire and a plurality of porous heat exchange enhancement blocks are provided in the preheating chamber, the electric heating wire is used to heat the reaction gas in the preheating chamber, and the plurality of porous heat exchange enhancement blocks are arranged along the flow direction of the reaction gas to enhance the turbulence and convection heat transfer coefficient during the flow of the reaction gas.

[0026] Preferably, the electric heating wire is embedded in the inner wall surface of the preheater body in a spiral structure along the flow direction of the reaction gas, and both ends of the electric heating wire extend out of the preheater body and are electrically connected to the battery through a thermostat, and the thermostat is used to control the working temperature of the electric heating wire;

[0027] A second thermal insulation layer is also provided on the outer wall surface of the preheater body.

[0028] Preferably, the reforming reactor also includes a reactor body, a combustion chamber is provided in the reactor body, an ignition subsystem is provided on the reactor body, the ignition subsystem is used to ignite the reaction gas transported into the reforming reactor, the ignition subsystem includes an ignition needle and a high-voltage package, the high-voltage package is connected to a battery, the high-voltage package is powered by the battery and increases the voltage, the high-voltage package is connected to the ignition needle through an insulated wire, the ignition needle extends into the combustion chamber, and the reaction gas is burned in the combustion chamber by ignition.

[0029] Preferably, a combustion-coupled reforming subsystem is provided in the combustion chamber, and the combustion-coupled reforming subsystem includes a porous media block assembly and a reforming tube arranged in sequence along the flow direction of the reaction gas, the porous media block assembly includes a plurality of porous media blocks with different pore densities, the reforming tube is used to transport reforming fuel, and the reforming tube is spirally coiled in the combustion chamber along the flow direction of the reaction gas.

[0030] Preferably, the thermoelectric power generation subsystem includes a thermoelectric power generation sheet, which is installed on the outer wall of the reactor body. The thermoelectric power generation sheet is electrically connected to a DC-DC converter through an insulated wire, and the DC-DC converter is electrically connected to the battery.

[0031] A fuel autothermal reforming reaction method suitable for extreme combustion conditions, using the above-mentioned fuel autothermal reforming reaction system suitable for extreme combustion conditions, comprises the following steps:

[0032] Step 1) During a cold start of the system, the pipeline flow channel subsystem proportions the reaction gas and delivers it to the electric preheater, which delivers the heated reaction gas to the reforming reactor;

[0033] Step 2) After the reaction gas forms a stable porous medium combustion in the reforming reactor, the electric preheater is turned off, and the pipeline flow channel subsystem partially transports the reaction gas to the waste heat recovery heat exchanger. The waste heat recovery heat exchanger and the electric preheater respectively transport the heated reaction gas to the reforming reactor;

[0034] Step 3) After the temperature of the electric heater drops to the deactivation temperature (eg, 100° C.), all the reaction gas is transported to the waste heat recovery heat exchanger, which then transports the heated reaction gas to the reforming reactor.

[0035] Compared with the prior art, the present invention has the following advantages:

[0036] 1. This solution preheats the reaction gas before combustion and causes the reaction gas to undergo porous medium combustion in the reforming reactor. The preheating and porous medium combustion technology expands the range of fuel types that can be used in the fuel autothermal reforming reaction system to include fuels that are difficult to burn, which is conducive to the development and utilization of new fuels (such as ammonia) and low calorific value fuels (such as low-concentration gas).

[0037] 2. This scheme improves the upper limit of the fuel-rich equivalent ratio of the fuel autothermal reforming reaction system in the fuel partial combustion oxidation operation mode through porous media combustion technology, thereby improving the reforming energy efficiency of the fuel autothermal reforming reaction system.

[0038] 3. This solution uses thermoelectric power generation technology to convert part of the energy in the fuel autothermal reforming process into electrical energy and continuously store it in the battery. This solves the cold start power consumption problem faced by the fuel autothermal reforming reaction system with electric heating power supply in mobile applications, and also solves the problem of electrical energy self-sufficiency of the fuel autothermal reforming reaction system. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Attachment Figure 1 This is a system block diagram of a fuel autothermal reforming reaction system suitable for use under extreme combustion conditions;

[0040] Attachment Figure 2 This is a schematic structural diagram of an electric preheater in a fuel autothermal reforming reaction system suitable for use under extreme combustion conditions according to the present invention;

[0041] Attachment Figure 3 Schematic diagram of the structure of the reforming reactor in the fuel autothermal reforming reaction system suitable for use under extreme combustion conditions of the present invention;

[0042] Attachment Figure 4 It is a cross-sectional view of a reforming reactor in a fuel autothermal reforming reaction system suitable for use under extreme combustion conditions according to the present invention.

[0043] Explanation of the accompanying symbols: electric heating preheater 1, preheater body 101, electric heating wire 102, porous heat exchange strengthening block 103, second insulation layer 104, temperature controller 105, reforming reactor 2, reactor body 201, ignition needle 202, thermoelectric power generation plate 203, water cooling head 204, bolt pressing plate set 205, window 206, reforming tube 207, porous medium block assembly 208, waste heat recovery heat exchanger 3, pipeline flow subsystem 4, product collection and storage subsystem 5, flue gas treatment device 6, battery 7. DETAILED DESCRIPTION

[0044] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. The components of the embodiments of the present invention generally described and shown in the drawings herein can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0045] It should be noted that similar reference numerals and letters denote similar items in the following figures. Therefore, once an item is defined in one figure, it does not require further definition or explanation in subsequent figures. In the description of the present invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the figures, or the orientations or positional relationships in which the inventive product is typically placed when in use. These terms are intended solely to facilitate the description of the present invention and simplify the description. They do not indicate or imply that the devices or components referred to must have a specific orientation, be constructed, or operate in a specific orientation, and are therefore not to be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third," etc., are used solely to distinguish descriptions and are not to be construed as indicating or implying relative importance. Furthermore, terms such as "horizontal" and "vertical" do not imply that a component must be absolutely horizontal or overhanging, but rather may be slightly tilted. For example, "horizontal" simply refers to a direction that is more horizontal than "vertical," and does not imply that the structure must be completely horizontal, but rather may be slightly tilted. In the description of the present invention, it should also be noted that, unless otherwise expressly specified or limited, the terms "disposed," "installed," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; they may refer to mechanical connections or electrical connections; they may refer to direct connections or indirect connections through an intermediate medium; and they may refer to internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0046] As attached Figure 1 As shown, this solution provides a fuel autothermal reforming reaction system suitable for extreme combustion conditions, including a pipeline flow subsystem 4, an electric heating preheater 1, a reforming reactor 2, a waste heat recovery heat exchanger 3, a product collection and storage subsystem 5, and a flue gas treatment device 6.

[0047] Specifically, the electric heating preheater 1 is used to preheat the reaction gas entering the combustion chamber during the cold start of the fuel autothermal reforming reaction system, thereby improving its combustion activity and expanding its flammability limit range; the reforming reactor 2 is used to reform the fuel, while recovering part of the heat released by the combustion chamber and converting and storing it into electrical energy to achieve self-sufficiency in electricity consumption of the system; the waste heat recovery heat exchanger 3 is used to recover the heat of high-temperature flue gas and reforming products, so as to replace the electric heating preheater 1 after the system completes the cold start to increase the temperature of the reaction gas entering the combustion chamber, and at the same time, through convection and heat conduction heat exchange, the waste heat of the high-temperature flue gas and reforming products is recovered to the unburned reaction gas and the fuel to be reformed respectively. , in order to increase the initial temperature of the two, enhance the reaction activity of the two and improve the energy efficiency of the system; the product collection and storage subsystem 5 is used to separate and store the reforming products at low temperature after waste heat recovery or directly store them; the flue gas treatment device 6 is used to treat the flue gas discharged by the burner and remove environmentally harmful substances in the flue gas; the pipeline flow channel subsystem 4 is used to achieve on-demand proportioning and sufficient mixing of the reaction gas, and connect the various subsystems of the system through the flow channel, forming an airflow circulation network by controlling the on-off and flow direction of the airflow, and at the same time, the temperature values ​​of the fluid at different positions are detected by sensors at various locations on the flow channel, so as to feedback control the gas flow to achieve suitable reforming conditions.

[0048] In this embodiment, the pipeline flow channel subsystem 4 includes a gas source, a gas mass flow controller, a gas mixer, a pipeline, a valve, a temperature measuring thermocouple, a connector, a first insulation layer, and a controller. The gas source is used to provide fuel, oxidant gas, and reforming fuel; the gas mass flow controller is used to control and distribute the target reaction gas composition ratio and flow rate, that is, to supply the fuel, oxidant gas, and reforming fuel in a quantitative proportion according to demand; the gas mixer is used to achieve sufficient mixing of the reaction gases; the valve controls the opening and closing of the flow channel, the direction of the gas, and prevents gas backflow; the temperature measuring thermocouple is used to measure the temperature of the gas at different positions in the flow channel; the pipeline and connector are used to connect the above-mentioned components and other subsystems to form a gas circulation network. The pipeline connects the various subsystems and equipment of the system through the connector to form a fluid network. The temperature measuring thermocouple detects the temperature value of the gas at different measuring points of the system, and cooperates with the controller to control the flow rate of each gas to control the appropriate reforming reaction conditions. The first insulation layer is laid outside the entire fluid network of the system to reduce the amount of heat dissipated by the system to the environment and improve the overall energy efficiency of the system. In this way, the prepared reaction gas and reforming fuel will flow through the pipeline flow subsystem 4 in sequence through the electric heating preheater 1, the reforming reactor 2, the waste heat recovery heat exchanger 3, and the product collection and storage subsystem 5 to complete the entire fuel autothermal reforming process.

[0049] As attached Figure 2As shown, in this embodiment, the electric heating preheater 1 includes a preheater body 101, a preheating chamber is provided in the preheater body 101, and a second thermal insulation layer 104 is further provided on the outer wall surface of the preheater body 101, and the second thermal insulation layer 104 is used to reduce the heat dissipation of the electric heating preheater 1 to the environment and improve the energy efficiency of the system; an electric heating wire 102 and a plurality of porous heat exchange enhancement blocks 103 are provided in the preheating chamber, and the electric heating wire 102 is used to heat the reaction gas in the preheating chamber, and the plurality of porous heat exchange enhancement blocks 103 are arranged along the flow direction of the reaction gas to enhance the turbulence and convective heat transfer coefficient during the flow of the reaction gas, so as to enhance the convective heat transfer and improve the heat exchange efficiency; the porous heat exchange enhancement block 103 can be made of metal to improve the heat exchange capacity and heat storage capacity, and further enhance the heat exchange effect. The electric heating wire 102 is embedded in the wall of the preheater body 101 in a spiral structure along the flow direction of the reaction gas. The electric heating wire 102 is used to generate heat and transfer the heat to the inner wall of the preheater body 101 through heat conduction to carry out convection heat exchange with the reaction gas. The two ends of the electric heating wire 102 extend out of the preheater body 101 and are electrically connected to the battery 7 through the thermostat 105. The thermostat 105 is used to control the working temperature of the electric heating wire 102. In this way, the electric heating wire 102 converts electrical energy into thermal energy, which is transferred to the inner wall surface of the preheater body 101 by heat conduction. When the reaction gas flows through the preheating chamber of the electric heating preheater 1, it absorbs heat from the inner wall surface of the preheater body 101 by heat conduction and convection, thereby increasing the temperature of the reaction gas and enhancing its reaction activity. At the same time, the battery 7 stores and provides the electrical energy required by the system's electrical equipment. The temperature controller 105 realizes the setting and control of the working temperature of the electric heating wire 102, and cooperates with the gas mass flow controller to control the reaction gas flow rate, thereby achieving the purpose of adjusting the preheating temperature of the reaction gas.

[0050] As attached Figure 3 and attached Figure 4 As shown, in this embodiment, the reforming reactor 2 includes a reactor body 201, which contains a combustion chamber, a combustion-coupled reforming subsystem, and an ignition subsystem, a thermoelectric subsystem, a viewing window 206, and a thermocouple. The ignition subsystem is used for ignition during system startup. After system startup, the thermoelectric subsystem absorbs some heat from the outer wall of the reactor body, converting it into electrical energy and storing it. The combustion-coupled reforming subsystem is used to achieve autothermal reforming of the fuel under extreme combustion conditions.

[0051] Specifically, the ignition subsystem is used to ignite the reactant gas delivered to the reforming reactor 2. The ignition subsystem includes an ignition needle 202 and a high-voltage transformer. The high-voltage transformer is connected to the battery 7, which is connected to the ignition needle 202 via an insulated wire. The ignition needle 202 extends into the combustion chamber. The high-voltage transformer boosts the output voltage of the battery 7. The high voltage breaks through the air and forms a discharge arc at the tip of the ignition needle 202 for ignition. This ignition causes the reactant gas to burn in the combustion chamber. Specifically, the ignition needle 202 is mounted on the wall of the reactor body 201 using a threaded through hole. Furthermore, to ensure the reliability of successful ignition, multiple sets of ignition needles 202 can be installed for multi-point ignition.

[0052] The thermoelectric subsystem includes thermoelectric generator chips 203, a water-cooled head 204, a DC-DC converter, and a bolted plate assembly 205. The thermoelectric subsystem absorbs some of the heat released by the combustion of the reactant gases and converts this heat into electricity through thermoelectric power generation, which is stored in a battery 7. The battery 7 is used to power the fuel autothermal reforming reaction system. Specifically, the water-cooled head 204 and thermoelectric generator chips 203 are stacked one on top of the other and mounted on the outer wall of the reactor body 201 using the bolted plate assembly 205. The thermoelectric generator chips 203 are electrically connected to the DC-DC converter via insulated wires, which in turn are electrically connected to the battery 7. In this way, after the reforming reactor 2 is successfully ignited, the heat generated by the combustion will cause the temperature of the reactor body 201 to rise rapidly. Through heat conduction, the hot end surface of the thermoelectric power generation plate 203 will be heated, and the cooling water continuously flowing in the water-cooled head 204 will continue to take away the heat, which ensures that there is a large temperature difference between the hot and cold end surfaces of the thermoelectric power generation plate 203. Through the thermoelectric effect, the thermoelectric power generation plate 203 converts part of the thermal energy into electrical energy, and the generated electrical energy is further converted into the charging voltage of the battery 7 through the DC-DC converter, thereby realizing continuous charging of the battery 7.

[0053] The combustion-coupled reforming subsystem includes a porous medium block assembly 208 and a reforming tube 207 arranged in sequence along the flow direction of the reaction gas. The porous medium block assembly 208 includes multiple porous medium blocks with different pore densities. The multiple porous medium blocks with different pore densities are placed in the combustion chamber. The porous medium blocks with high pore density are used to prevent backfire, and the porous medium blocks with low pore density are used to make the combustion appear as porous medium combustion. The reforming tube 207 is installed in the downstream position in the reactor body 201, and its interior is used to transport reforming fuel. The reforming tube 207 is spirally coiled in the combustion chamber along the flow direction of the reaction gas, which can increase the residence time of the reforming fuel in the reforming tube 207 to absorb more heat generated in the combustion chamber; at the same time, a catalyst can be filled in the reforming tube 207 to reduce the temperature conditions for the reforming reaction and improve the reforming degree of the fuel. Specifically, the combustion chamber is a square flow channel, and a porous medium block and a reforming tube 207 are installed inside it. Thermocouples, ignition needles 202 in the ignition subsystem, and thermoelectric generation plates 203 in the thermoelectric generation subsystem are installed on its wall; the porous medium block is used to heat the reaction gas by radiation and heat conduction to achieve the effect of broadening the flame stability limit; the window 206 on the reactor body 201 is used to observe the combustion conditions in the combustion chamber, the working status of the ignition needle 202, etc. in real time, so that the ignition needle 202 can be discovered and replaced in time when it is damaged; the thermocouple is used to monitor the temperature in the combustion chamber and to determine whether the ignition is successful when the system is started. In this way, after the reactant gas enters the combustion chamber, it is ignited by the ignition needle 202, releasing a large amount of heat, rapidly heating the porous medium block. The flame then sinks to the porous medium block with low pore density, forming a stable porous medium combustion. The porous medium block in a high-temperature red-hot state will continuously heat the reactant gas entering the combustion chamber through radiation and convection heat exchange, increasing the combustion activity of the reactant gas, thereby achieving stable combustion under extreme operating conditions. At the same time, the high-temperature flue gas generated by the combustion will directly flush the downstream reforming tube 207, heating it to the reforming reaction temperature of the fuel, achieving endothermic reforming of the fuel in the reforming tube 207. In summary, the combustion-coupled reforming subsystem cooperates with the ignition subsystem and the thermoelectric power generation subsystem to realize the combustion and heat release of the reaction gas in the combustion chamber. The released heat will be mainly used for fuel reforming in the reforming tube 207 of the reforming reactor 2. Part of the heat will be recovered through the thermoelectric power generation module to generate the electrical energy required for the system operation. The voltage generated by the thermoelectric power generation chip 203 is converted into the charging voltage of the battery 7 through the DC-DC converter, so as to realize continuous charging of the battery 7 when the reforming reactor 2 is working.

[0054] The waste heat recovery heat exchanger 3 can be a shell and tube heat exchanger or a plate heat exchanger, which is used to recover heat from high-temperature flue gas and reforming products to increase the initial temperature of the reaction gas and reforming fuel, improve the combustion activity of the reaction gas, expand its flammable limit range, and at the same time reduce the exhaust temperature of the flue gas and reforming products and improve the system energy efficiency.

[0055] The flue gas treatment device 6 includes a denitrification device for reducing the NOx content and pollutants in the flue gas so that they meet the emission standards before being discharged into the atmosphere.

[0056] The product collection and storage subsystem 5 includes a component separator and a storage. The reformed product will be transported to the component separator for concentration and separation of combustible components, and then stored in the storage. It can also be directly stored in the storage.

[0057] This solution also provides a fuel autothermal reforming reaction method suitable for extreme combustion conditions, which uses the above-mentioned fuel autothermal reforming reaction system suitable for extreme combustion conditions; and includes the following steps:

[0058] Step 1) During a cold start of the system, the pipeline flow channel subsystem 4 proportions the reaction gas and delivers it all to the electric preheater 1, which then delivers the heated reaction gas to the reforming reactor 2;

[0059] Step 2) After the reaction gas forms a stable porous medium combustion in the reforming reactor 2, the electric preheater 1 is turned off, and the pipeline flow subsystem 4 transports part of the reaction gas to the waste heat recovery heat exchanger 3. The waste heat recovery heat exchanger 3 and the electric preheater 1 respectively transport the heated reaction gas to the reforming reactor 2;

[0060] Step 3) After the temperature of the electric preheater 1 drops to the deactivation temperature, such as 100° C., all the reaction gas is transported to the waste heat recovery heat exchanger 3 , and the waste heat recovery heat exchanger 3 transports the heated reaction gas to the reforming reactor 2 .

[0061] The specific working process of the present invention is:

[0062] When the heat released by partial combustion and oxidation of the fuel is used for reforming the surplus fuel, the operating temperature of the electric preheater 1 is first set by the thermostat 105, and the power supply (i.e., the battery 7) is turned on to start the electric preheater 1 to heat up; when the electric preheater 1 reaches the target set temperature, the gas mass flow controller is controlled by the controller to quantitatively proportion the different gases of the gas source according to the target working condition, and the fuel and oxidant gas will be sent to the gas mixer through the pipeline for sufficient mixing; the mixed reaction gas will be preheated by opening the valve when the system is cold started; the preheated reaction gas will The gas flows to the reforming reactor 2 through the pipeline, the high-voltage package switch is turned on to start ignition, and the temperature in the combustion chamber is detected by the thermocouple installed on the reforming reactor 2. When it is determined that the ignition is successful, the high-voltage package switch is turned off, the ignition is stopped, and the cooling water switch of the water-cooled head 204 is turned on; after observing that a stable porous medium combustion flame has been formed in the combustion chamber through the window 206, the valve flowing to the waste heat recovery heat exchanger 3 (downstream connected to the reforming reactor 2) is slowly opened to allow a part of the fully mixed reaction gas to flow to the waste heat recovery heat exchanger 3 (downstream connected to the reforming reactor 2); the power supply of the electric heating preheater 1 is turned off, and the power supply to the electric heating preheater is gradually turned off. The valve of the preheater 1 is closed, and after the temperature of the electric preheater 1 drops to a lower level, the valve to the electric preheater 1 is completely closed, so that all the fully mixed reaction gases flow to the waste heat recovery heat exchanger 3 (connected to the reforming reactor 2 at the downstream). In this way, the reaction gases will absorb the waste heat of the high-temperature reformed products through the waste heat recovery heat exchanger 3 (connected to the reforming reactor 2 at the downstream). At the same time, due to the large temperature difference between the hot and cold end faces of the thermoelectric power generation sheet 203, the thermoelectric effect will convert part of the heat generated by the reactor body 201 into electrical energy, and the electrical energy will be continuously stored in the battery 7 through the DC-DC converter. The high-temperature reformed products discharged from the combustion chamber will be After the temperature is lowered by the waste heat recovery heat exchanger 3 (connected to the reforming reactor 2 downstream), it is sent to the component separator through the pipeline for product concentration and separation, and then sent to the storage for storage; when the system is shut down, the controller first controls the gas mass flow controller to shut down the various gases in the gas source, and closes the component separator and storage; then the gas mass flow controller is controlled to introduce inert gas to cool the system. When the temperature measurement value of the thermocouple at each high-temperature measuring point drops below the safe value, the controller controls the gas mass flow controller to shut down the inert gas; the cooling water supplied to the water-cooled head 204 is shut down, and the power supply to the system is cut off.

[0063] When a partition-wall reactor is used to separate fuel combustion and reforming in different spaces, the operating temperature of the electric preheater 1 is first set by the temperature controller 105, and the power is turned on to start the electric preheater 1 to heat up; when the electric preheater 1 reaches the target set temperature, the gas mass flow controller is controlled by the controller to quantitatively proportion the different gases of the gas source according to the target working condition, and the fuel and oxidant gas will be sent to the gas mixer through the pipeline for sufficient mixing; when the system is cold started, the mixed reaction gas will be preheated by opening the valve to flow into the electric preheater 1; the preheated reaction gas will flow to the reforming reactor 2 through the pipeline, and the high-voltage package switch will be turned on to start ignition, and the thermocouple installed on the reforming reactor 2 will detect the combustion The temperature in the chamber, when it is determined that the ignition is successful, turn off the high-voltage coil switch, stop ignition, and turn on the cooling water switch of the water-cooled head 204; after observing through the window 206 that a stable porous medium combustion flame has been formed in the combustion chamber, the gas mass flow controller is controlled by the controller to quantitatively deliver the fuel gas to be reformed from the gas source according to the target working condition; slowly open the valve flowing to the waste heat recovery heat exchanger 3 (connected to the reforming reactor 2 downstream) to allow a part of the fully mixed reaction gas to flow to the waste heat recovery heat exchanger 3 (connected to the reforming reactor 2 downstream); turn off the power supply of the electric heating preheater 1, gradually close the valve flowing to the electric heating preheater 1, and completely close the valve flowing to the electric heating preheater 1 after the temperature of the electric heating preheater 1 drops to a lower level The door allows all the fully mixed reaction gases to flow to the waste heat recovery heat exchanger 3 (connected to the reforming reactor 2 at the downstream end). In this way, the reaction gases will absorb the waste heat of the high-temperature flue gas through the waste heat recovery heat exchanger 3 (connected to the reforming reactor 2 at the downstream end); the fuel gas to be reformed will first pass through the waste heat recovery heat exchanger 3 (connected to the reforming pipe 207 at the downstream end) to absorb the waste heat of the high-temperature reforming product and then enter the reforming pipe 207 for endothermic reforming; at the same time, due to the large temperature difference between the hot and cold end faces of the thermoelectric power generation plate 203, the thermoelectric effect will convert part of the heat generated by the reforming reactor 2 body into electrical energy, and the electrical energy will be continuously stored in the battery 7 through the DC-DC converter; the high-temperature flue gas discharged from the combustion chamber will pass through the waste heat recovery heat exchanger 3 (connected to the reforming reactor 2 at the downstream end 2) After the temperature is lowered, it is sent to the flue gas treatment device 6 via a pipeline to reduce the concentration of the restricted pollutants before being discharged into the atmosphere; the high-temperature reformed product discharged from the reforming pipe 207 will first pass through the waste heat recovery heat exchanger 3 (connected to the reforming pipe 207 downstream) to reduce the temperature, and then be sent to the component separator via a pipeline for product concentration and separation, and then sent to the storage for storage; when the system is shut down, the controller first controls the gas mass flow controller to shut off each gas source, the component separator, and the storage; then the gas mass flow controller is controlled to pass inert gas to cool the system. When the temperature measurement value of the thermocouple at each high-temperature measuring point drops below the safe value, the controller controls the gas mass flow controller to shut off the inert gas;Turn off the cooling water supply to the water-cooled head 204 and cut off the power supply to the system.

[0064] The combustion effect of this scheme is explained below with a specific experimental data:

[0065] Three SiC porous media blocks with pore densities of 60 PPI, 30 PPI, and 10 PPI, each 20 mm thick, were stacked in sequence within an 80*80*210 mm burner with a wall thickness of 6 mm. An ignition needle (for ignition), a sheathed K-type thermocouple (for measuring combustion chamber temperature), and a heat exchange coil (for fuel reforming) were installed behind the SiC porous media blocks to form a porous media burner (the burner was not insulated). Experimental measurements of the rich and lean flammability limits of methane at ambient temperature and pressure were conducted using this porous media burner. The experimental results show that at total methane / air flow rates of 50 SLPM and 20 SLPM, respectively, the rich and lean flammability limit equivalence ratios of the methane / air mixture within the porous media burner were 0.4 (methane volume fraction 4.03%) and 1.6 (methane volume fraction 14.39%), achieving stable combustion of methane at both ultra-low and high concentrations. In addition, stable combustion of pure ammonia at room temperature and pressure was successfully achieved in the porous medium burner. In the experiment, the stoichiometric ammonia / air mixture could burn stably from 8 SLPM ignition to a total flow rate gradually increased to 50 SLPM (the full scale of the gas flow controller). The temperature of the combustion chamber reached a maximum of 970°C. At a total flow rate of 50 SLPM, the lean combustion limit equivalence ratio of the ammonia / air mixture was 0.55 (ammonia gas volume fraction 13.3%), achieving stable combustion of ammonia at room temperature and pressure and a wide equivalence ratio.

[0066] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the technical solutions. Those skilled in the art should understand that modifications or equivalent replacements of the technical solutions of the present invention that do not depart from the purpose and scope of the technical solutions of the present invention should be included in the scope of the claims of the present invention.

Claims

1. A fuel autothermal reforming reaction system suitable for extreme combustion conditions, characterized in that: Pipeline flow channel subsystem, electric heating preheater, reforming reactor and first waste heat recovery heat exchanger, second waste heat recovery heat exchanger; The pipeline flow channel subsystem is connected to the electric heating preheater and the first waste heat recovery heat exchanger respectively, and the pipeline flow channel subsystem proportions and fully mixes the reaction gas before delivering it to the electric heating preheater or the first waste heat recovery heat exchanger, and proportions the reformed fuel before delivering it to the second waste heat recovery heat exchanger; The electric preheater is connected to the reforming reactor, and is used to heat the reaction gas when the system is cold started, and to deliver the heated reaction gas to the reforming reactor; The reforming reactor is connected to the first waste heat recovery heat exchanger and the second waste heat recovery heat exchanger. The reforming reactor is used to achieve the coupling of the exothermic heat of the porous medium combustion of the reaction gas and the heat absorption of the reforming fuel. The reaction gas releases heat in the form of porous medium combustion, and the heat released by the combustion of the reaction gas is absorbed by the reforming fuel. The reforming reactor transmits the high-temperature flue gas generated by the combustion of the reaction gas to the first waste heat recovery heat exchanger, and transmits the reforming product formed after the reforming of the reforming fuel to the second waste heat recovery heat exchanger. The first waste heat recovery heat exchanger is used to recover the high-temperature flue gas discharged from the reforming reactor, and the second waste heat recovery heat exchanger is used to recover the waste heat of the reformed product. Through convection and heat conduction heat exchange, the waste heat of the high-temperature flue gas and the reformed product are respectively recovered into the reaction gas to be burned and the fuel to be reformed after the cold start, and the heated reaction gas to be burned and the fuel to be reformed are delivered to the reforming reactor; The reforming reactor includes a reactor body, a combustion chamber is provided in the reactor body, an ignition subsystem is provided on the reactor body, the ignition subsystem is used to ignite the reaction gas delivered to the reforming reactor, the ignition subsystem includes an ignition needle and a high-voltage package, the high-voltage package is connected to a battery, the high-voltage package is powered by the battery and the voltage is increased, the high-voltage package is connected to the ignition needle through an insulated wire, the ignition needle extends into the combustion chamber, and the reaction gas is burned in the combustion chamber by ignition; A combustion-coupled reforming subsystem is provided in the combustion chamber. The combustion-coupled reforming subsystem includes a porous medium block assembly and a reforming tube arranged in sequence along the flow direction of the reaction gas. The porous medium block assembly includes multiple porous medium blocks with different pore densities. The reforming tube is used to transport reforming fuel, and the reforming tube is spirally coiled in the combustion chamber along the flow direction of the reaction gas.

2. The fuel autothermal reforming reaction system suitable for extreme combustion conditions according to claim 1, characterized in that: The reforming reactor includes a thermoelectric subsystem, which absorbs part of the heat released by the combustion of the reaction gas and converts the heat into electrical energy through thermoelectric power generation and stores it in a battery. The battery is used to supply power to the fuel autothermal reforming reaction system.

3. The fuel autothermal reforming reaction system suitable for extreme combustion conditions according to claim 1, characterized in that: The fuel autothermal reforming reaction system also includes a product collection and storage subsystem and a flue gas treatment device; The product collection and storage subsystem is connected to the second waste heat recovery heat exchanger and is used to concentrate and separate the reformed product after waste heat recovery and then store it or store it directly; The flue gas treatment device is connected to the first waste heat recovery heat exchanger and is used to treat pollutants in the flue gas after waste heat recovery.

4. The fuel autothermal reforming reaction system suitable for extreme combustion conditions according to claim 1, characterized in that: The pipeline flow channel subsystem includes a gas source, a gas mass flow controller and a gas mixer connected in sequence; The gas source is used to provide fuel, oxidant gas and reforming fuel; The gas mass flow controller is used to supply the fuel, oxidant gas and reformed fuel in a quantitative proportion as needed, and deliver the proportioned fuel and oxidant to the gas mixer, and deliver the proportioned reformed fuel to the second waste heat recovery heat exchanger; The gas mixer is used to fully mix the fuel and oxidant after proportioning to form a reaction gas, and to transport the reaction gas to the electric heating preheater or the first waste heat recovery heat exchanger.

5. The fuel autothermal reforming reaction system suitable for extreme combustion conditions according to claim 2, characterized in that: The electric heating preheater includes a preheater body, a preheating chamber is provided in the preheater body, an electric heating wire and a plurality of porous heat exchange enhancement blocks are provided in the preheating chamber, the electric heating wire is used to heat the reaction gas in the preheating chamber, and the plurality of porous heat exchange enhancement blocks are arranged along the flow direction of the reaction gas to enhance the turbulence and convection heat transfer coefficient during the flow of the reaction gas.

6. The fuel autothermal reforming reaction system suitable for extreme combustion conditions according to claim 5, characterized in that: The electric heating wire is embedded in the inner wall surface of the preheater body in a spiral structure along the flow direction of the reaction gas, and the two ends of the electric heating wire extend out of the preheater body and are electrically connected to the battery through a thermostat, and the thermostat is used to control the working temperature of the electric heating wire; A second thermal insulation layer is also provided on the outer wall surface of the preheater body.

7. The fuel autothermal reforming reaction system suitable for extreme combustion conditions according to claim 6, characterized in that: The thermoelectric power generation subsystem includes a thermoelectric power generation sheet, which is installed on the outer wall of the reactor body. The thermoelectric power generation sheet is electrically connected to a DC-DC converter through an insulated wire, and the DC-DC converter is electrically connected to the battery.

8. A fuel autothermal reforming reaction method suitable for extreme combustion conditions, characterized in that: The fuel autothermal reforming reaction system suitable for extreme combustion conditions as claimed in claim 1 comprises the following steps: Step 1) During a cold start of the system, the pipeline flow channel subsystem proportions the reaction gas and delivers it to the electric preheater, which delivers the heated reaction gas to the reforming reactor; Step 2) After the reaction gas forms a stable porous medium combustion in the reforming reactor, the electric preheater is turned off, and the pipeline flow channel subsystem partially delivers the reaction gas to the first waste heat recovery heat exchanger. The first waste heat recovery heat exchanger and the electric preheater respectively deliver the heated reaction gas to the reforming reactor; Step 3) After the temperature of the electric preheater is lowered to the deactivation temperature, all the reaction gas is transported to the first waste heat recovery heat exchanger, and the first waste heat recovery heat exchanger transports the heated reaction gas to the reforming reactor.

Images