Light-coal complementary methane preparation system with near-zero carbon emission

Abstract

The invention provides a light coal complementary methane preparation system with near-zero carbon emission. The light coal complementary methane preparation system with near-zero carbon emission comprises a coal gasification assembly, a hydrogen production assembly and a methanation assembly. The coal gasification assembly is suitable for gasifying raw coal to generate carbon monoxide. The hydrogen production assembly is suitable for electrolyzing condensate water generated in the raw coal gasification process to generate hydrogen. The methanation assembly is suitable for enabling hydrogen generated by the hydrogen production unit and carbon monoxide generated by the coal gasification assembly to be subjected to methanation reaction to obtain methane, energy consumption and the use amount of water resources can be reduced, meanwhile, the influence on the environment is reduced, and clean, efficient and sustainable development of coal energy conversion is achieved.

Description

Technical Field

[0001] At least one embodiment of the present disclosure relates to the technical field of pyrolysis and gasification, and methane production, and in particular to a light-coal complementary methane production system with near-zero carbon emissions. Background Art

[0002] Coal is an important energy source, accounting for more than half of the global energy consumption structure. In recent years, with the continuous optimization of the coal energy conversion industry, the increasing scale of the industry, and the accelerated technological iteration, modern coal conversion technology has been widely used and developed.

[0003] However, the current coal energy conversion production practice still faces some challenges: first, the energy consumption in the production process is relatively high, which affects the overall energy efficiency; second, the consumption of water resources is large, which puts pressure on the sustainable use of water resources; third, in order to control pollutant emissions, a large amount of manpower, material and financial resources are needed. Summary of the invention

[0004] In order to solve at least one of the above-mentioned technical problems, the present disclosure provides a near-zero carbon emission light-coal complementary methane production system, which can reduce energy consumption and water resource usage while reducing the impact on the environment, so as to achieve clean, efficient and sustainable development of coal energy conversion.

[0005] As one aspect of an embodiment of the present disclosure, a near-zero carbon emission light-coal complementary methane production system is provided, comprising a coal gasification component, a hydrogen production component and a methanation component. The coal gasification component is suitable for gasifying raw coal to produce carbon monoxide. The hydrogen production component is suitable for electrolyzing condensed water produced in the process of gasifying the raw coal to produce hydrogen. The methanation component is suitable for causing the hydrogen produced by the hydrogen production unit and the carbon monoxide produced by the coal gasification component to undergo a methanation reaction to obtain methane.

[0006] According to an embodiment of the present disclosure, the above-mentioned coal gasification component includes a pyrolysis furnace, a burner, a condenser and a gasifier. The pyrolysis furnace is suitable for pyrolyzing the above-mentioned raw coal to produce coal char and pyrolysis oil gas. The burner is suitable for burning the above-mentioned pyrolysis oil gas under the assistance of the oxygen generated in the above-mentioned electrolysis process to obtain flue gas. The condenser is suitable for condensing the above-mentioned flue gas to separate the above-mentioned condensed water and carbon dioxide. The gasifier is suitable for using the carbon dioxide from the above-mentioned condenser as a gasifying agent to gasify the coal char from the above-mentioned pyrolysis furnace to produce the above-mentioned carbon monoxide, wherein the above-mentioned flue gas provides a high-temperature environment for the reaction of the above-mentioned coal char gasification before condensation. Wherein, the above-mentioned flue gas also provides a medium-high temperature environment for the above-mentioned raw coal to be pyrolyzed before condensation.

[0007] According to an embodiment of the present disclosure, the gasifier includes a furnace body, an outer furnace wall and a flue gas duct. A storage space is formed inside the furnace body, and the outer furnace wall is arranged outside the furnace body, and an outer flue is formed between the furnace body and the outer furnace wall. The flue gas duct is installed upright in the storage space, and the upper part of the flue gas duct is connected with the outer flue through a pipe. Among them, the burner is installed on the furnace body and is located below the flue gas duct, which is suitable for providing the flue gas from the bottom to the flue gas duct. The flue gas rises in the flue gas duct to heat the coal char flowing downward in the storage space and the carbon dioxide flowing upward, so that the coal char undergoes a gasification reaction. The cooled flue gas is discharged through the outer flue, and passes through the pyrolysis furnace through a conveying pipeline to provide the medium and high temperature environment for the pyrolysis of the raw coal.

[0008] According to an embodiment of the present disclosure, the furnace body further comprises a feed pipe. The feed pipe passes through the outer furnace wall and is installed on the top of the furnace body to communicate with the accommodation space, wherein the coal char enters the accommodation space via the feed pipe. The flue gas duct is located below the feed pipe, and the top of the flue gas duct is configured to be conical, so that the coal char falling on the top of the flue gas duct is evenly dispersed in the accommodation space.

[0009] According to an embodiment of the present disclosure, the gasifier further comprises a tubular member, which is horizontally extended and arranged below the flue gas duct and communicates with the flue gas duct, and the tubular member penetrates two opposite sides of the furnace body to guide the flue gas into the flue gas duct. There are two burners, which are symmetrically arranged at both ends of the axial direction of the tubular member to provide the flue gas by burning fuel.

[0010] According to an embodiment of the present disclosure, a discharge port is provided at the bottom of the furnace body, and the discharge port is suitable for allowing the ash generated by the gasification reaction of the coking coal to be discharged. The furnace body also includes a gas distribution plate, which is obliquely installed between the periphery of the discharge port and the furnace body, so that an air chamber adjacent to the accommodation space is formed between the gas distribution plate and the bottom wall and side wall of the furnace body. Among them, the carbon dioxide from the condenser enters the air chamber from the air inlet located at the lower part of the air chamber, and enters the accommodation space through the multiple through holes on the gas distribution plate, contacts the coal coke in the accommodation space, and causes the ash falling on the gas distribution plate to be discharged through the discharge port.

[0011] According to an embodiment of the present disclosure, the coal gasification component further includes a dryer, which is suitable for drying the raw coal to obtain dried raw coal and water vapor, and transporting the dried raw coal to the pyrolysis furnace for pyrolysis, and transporting the water vapor to the hydrogen production component. The delivery pipeline passes through the pyrolysis furnace and also passes through the dryer to provide a medium temperature environment for drying the raw coal, and the other end of the delivery pipeline is connected to the condenser to condense the flue gas after cooling.

[0012] According to an embodiment of the present disclosure, the hydrogen production assembly includes an electrolyzer and a photovoltaic panel. The electrolyzer is suitable for receiving the condensed water, and the photovoltaic panel is suitable for converting solar energy into electrical energy to electrolyze the condensed water in the electrolyzer.

[0013] According to an embodiment of the present disclosure, the above-mentioned hydrogen production component also includes a water purifier, which is suitable for filtering the above-mentioned condensed water before entering the above-mentioned electrolyzer.

[0014] According to an embodiment of the present disclosure, the methanation component includes a plurality of reactors arranged in cascade, and the plurality of reactors arranged in cascade are suitable for causing the carbon monoxide from the gasifier and the hydrogen from the hydrogen production component to undergo the methanation reaction step by step under the action of a catalyst. According to the flow direction of the carbon monoxide, the product gas generated by the reactor located downstream is used as a circulating gas to control the temperature of the reactor located in the first stage, and the product gas includes the methane and unreacted hydrogen and carbon monoxide.

[0015] According to the near-zero carbon emission light coal complementary methane production system provided by the embodiment of the present disclosure, the condensed water generated during the coal gasification process is used by the hydrogen production component to electrolyze and produce hydrogen, which not only reduces the demand for fresh water resources, but also realizes the recycling of water resources and reduces the consumption of water resources. The coal gasification component produces carbon monoxide (CO) by gasifying the raw coal. This process can release the energy in the coal more efficiently than directly burning coal, thereby improving the energy conversion efficiency. The methanation component can capture most of the carbon by converting carbon monoxide and hydrogen into methane, thereby significantly reducing the emission of carbon dioxide (CO2) and achieving the goal of near-zero carbon emissions. According to the near-zero carbon emission light coal complementary methane production system provided by the embodiment of the present disclosure, not only the graded and quality-based clean and efficient utilization of traditional fossil energy coal is realized, but also the absorption of renewable energy solar energy is improved, the near-zero emission of carbon dioxide and the comprehensive cascade utilization of multi-energy energy are realized, and the energy efficiency of the near-zero carbon emission light coal complementary methane production system is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The above and other objects, features and advantages of the present disclosure will become more apparent through the following description of the embodiments of the present disclosure with reference to the accompanying drawings, in which:

[0017] Figure 1 The composition diagram of the light-coal complementary methane production system with near-zero carbon emission according to an embodiment of the present disclosure is schematically shown;

[0018] Figure 2 Schematically shows a top view of a gasifier according to an embodiment of the present disclosure;

[0019] Figure 3 Schematically shows Figure 2 A cross-sectional view of the gasifier taken along line AA is shown;

[0020] Figure 4 A partial cross-sectional view schematically shows a burner according to an embodiment of the present disclosure; and

[0021] Figure 5 The composition diagram of the methanation assembly according to an embodiment of the present disclosure is schematically shown.

[0022] 1- Coal gasification components;

[0023] 11- Gasifier;

[0024] 111-furnace body;

[0025] 1111-accommodation space;

[0026] 1112-feeding pipe;

[0027] 1113-discharging port;

[0028] 1114-gas distribution plate;

[0029] 1115-air chamber;

[0030] 1116-air inlet;

[0031] 112 - outer furnace wall;

[0032] 113-external flue;

[0033] 1131-smoke outlet;

[0034] 114- Flue gas duct;

[0035] 115- tubular part;

[0036] 116- baffle;

[0037] 117- pipe fittings;

[0038] 12-burner;

[0039] 121-Central channel;

[0040] 122-gas fuel channel;

[0041] 123- solid fuel channel;

[0042] 124-combustion channel;

[0043] 2-Hydrogen production components;

[0044] 3-Methanation component;

[0045] 31-reactor;

[0046] 32-circulation compressor;

[0047] 33-Desulfurization tank. DETAILED DESCRIPTION

[0048] In order to make the objectives, technical solutions and advantages of the present disclosure more clearly understood, the present disclosure is further described in detail below in combination with specific embodiments and with reference to the accompanying drawings.

[0049] The terms used herein are only for describing specific embodiments and are not intended to limit the present disclosure. The terms "comprise", "include", etc. used herein indicate the existence of the features, steps, operations and / or components, but do not exclude the existence or addition of one or more other features, steps, operations or components.

[0050] All terms used herein, including technical and scientific terms, have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein should be interpreted as having a meaning consistent with the context of this specification, and should not be interpreted in an idealized or overly rigid manner.

[0051] When using expressions such as "at least one of A, B, and C, etc.", it should generally be interpreted as the meaning of the expression generally understood by those skilled in the art. For example, "a system having at least one of A, B, and C" should include but not be limited to a system having A alone, B alone, C alone, A and B, A and C, B and C, and / or A, B, C, etc. When using expressions such as "at least one of A, B, or C, etc.", it should generally be interpreted as the meaning of the expression generally understood by those skilled in the art. For example, "a system having at least one of A, B, or C" should include but not be limited to a system having A alone, B alone, C alone, A and B, A and C, B and C, and / or A, B, C, etc.

[0052] It should also be noted that the directional terms mentioned in the embodiments, such as "upper", "lower", "front", "back", "left", "right", etc., are only reference directions of the drawings and are not intended to limit the scope of protection of the present disclosure. Throughout the drawings, the same elements are represented by the same or similar reference numerals. Conventional structures or configurations will be omitted when they may cause confusion in the understanding of the present disclosure.

[0053] In the process of realizing the present disclosure, it is found that clean and efficient use of coal is not only an energy security option, but also an important technology related to carbon peak and carbon neutrality. Coal-to-natural gas (mainly methane) is an important way to cleanly transform and utilize coal, an important means to optimize the energy structure and ensure energy security, and an effective means to alleviate local air pollution. Solar water electrolysis to produce hydrogen is a clean energy production method that can reduce carbon emissions and meet the requirements of sustainable development.

[0054] Figure 1 The composition diagram of the light-coal complementary methane production system with near-zero carbon emission according to an embodiment of the present disclosure is schematically shown.

[0055] As one aspect of an embodiment of the present disclosure, a near-zero carbon emission light coal complementary methane production system is provided. As shown in FIG1 , the near-zero carbon emission light coal complementary methane production system includes a coal gasification component 1, a hydrogen production component 2, and a methanation component 3. The coal gasification component 1 is suitable for gasifying raw coal to produce carbon monoxide (CO). The hydrogen production component 2 is suitable for electrolyzing the condensed water (H2O) produced in the process of gasifying the raw coal to produce hydrogen (H2). The methanation component 3 is suitable for causing the hydrogen produced by the hydrogen production unit and the carbon monoxide produced by the coal gasification component 1 to undergo a methanation reaction to obtain methane (CH4).

[0056] According to the near-zero carbon emission light coal complementary methane production system provided by the embodiment of the present disclosure, the condensed water generated during the coal gasification process is used by the hydrogen production component 2 to electrolyze and produce hydrogen, which not only reduces the demand for fresh water resources, but also realizes the recycling of water resources and reduces the consumption of water resources. The coal gasification component 1 produces carbon monoxide (CO) by gasifying the raw coal. This process can release the energy in the coal more efficiently than directly burning coal, thereby improving the energy conversion efficiency. The methanation component 3 can capture most of the carbon by converting carbon monoxide and hydrogen into methane, thereby significantly reducing the emission of carbon dioxide (CO2) and achieving the goal of near-zero carbon emission. According to the near-zero carbon emission light coal complementary methane production system provided by the embodiment of the present disclosure, not only the graded and quality-based clean and efficient utilization of traditional fossil energy coal is realized, but also the absorption of renewable energy solar energy is improved, the near-zero emission of carbon dioxide and the comprehensive cascade utilization of multi-energy energy are realized, and the energy efficiency of the near-zero carbon emission light coal complementary methane production system is improved.

[0057] According to an embodiment of the present disclosure, the coal gasification assembly 1 includes a pyrolysis furnace, a burner 12, a condenser and a gasifier 11. The pyrolysis furnace is suitable for pyrolyzing raw coal to produce coal char and pyrolysis oil gas. The burner 12 is suitable for burning the pyrolysis oil gas under the support of oxygen generated during the electrolysis process to obtain flue gas. The condenser is suitable for condensing the flue gas and separating condensed water and carbon dioxide. The gasifier 11 is suitable for using the carbon dioxide from the condenser as a gasifying agent to gasify the coal char from the pyrolysis furnace to produce carbon monoxide, wherein the flue gas provides a high-temperature environment for the reaction of coal char gasification before condensation. Among them, the flue gas also provides a medium-high temperature environment for the raw coal to be pyrolyzed before condensation.

[0058] The efficient use of heat is achieved through the coal char and pyrolysis oil gas produced by the pyrolysis furnace and the combustion process of the pyrolysis oil gas in the burner 12. The flue gas provides a high-temperature environment for the gasification of coal char before condensation, and provides a medium-high temperature environment for the pyrolysis of raw coal, reducing the demand for external heat and improving the overall energy efficiency. The oxygen generated in the process of electrolysis of water is used in the burner 12 to assist combustion, reducing the generation of nitrogen oxides during the combustion process. At the same time, the condenser is used to effectively separate water and discharge carbon dioxide, and carbon dioxide is used as a gasification agent to reduce greenhouse gas emissions.

[0059] Figure 2 The top view of the gasifier according to the embodiment of the present disclosure is schematically shown. Figure 3 Schematically shows Figure 2 A cross-sectional view along line AA of the gasifier is shown.

[0060] According to the embodiments of the present disclosure, Figure 2 and Figure 3 As shown, the gasifier 11 includes a furnace body 111, an outer furnace wall 112 and a flue gas duct 114. A storage space 1111 is formed inside the furnace body 111, and the outer furnace wall 112 is arranged outside the furnace body 111, and an outer flue 113 is formed between the furnace body 111 and the outer furnace wall 112. The flue gas duct 114 is vertically installed in the storage space 1111, and the upper part of the flue gas duct 114 is connected with the outer flue 113 through a pipe 117. Among them, the burner 12 is installed on the furnace body 111 and is located below the flue gas duct 114, which is suitable for providing flue gas to the flue gas duct 114 from the bottom. The flue gas rises in the flue gas duct to heat the coal char flowing downward and the carbon dioxide flowing upward in the storage space 1111, so that the coal char undergoes a gasification reaction, and the cooled flue gas is discharged through the outer flue 113, and passes through the pyrolysis furnace through the conveying pipeline to provide a medium and high temperature environment for the pyrolysis of raw coal.

[0061] According to the gasifier 11 of the embodiment of the present disclosure, a flue gas duct 114 is upright installed in the furnace body 111, and flue gas is provided from the lower part of the flue gas duct 114 through a flue gas supply assembly, so that the flue gas rises in the flue gas duct 114, and can indirectly and evenly heat the gasification raw materials flowing downward and the gasification agent flowing upward in the accommodating space 1111, so that the temperature of the accommodating space 1111 is kept at a high temperature during the process of the flue gas being discharged through the external flue 113, so that the gasification raw materials undergo a gasification reaction under the action of the gasification agent and the high temperature, which helps to fully carry out the gasification reaction and improves the gasification efficiency. By setting up the flue gas duct 114 and the external flue 113, the high-temperature flue gas can transfer heat from the flue gas duct 114 and the external flue 113 to the accommodating space 1111 in the opposite direction, thereby increasing the contact area between the accommodating space 1111 and the high-temperature flue gas, realizing a multi-faceted radiation heat transfer method, providing a more uniform heat distribution for the accommodating space 1111, improving the uniformity of heating, increasing the thermal utilization efficiency of the high-temperature flue gas, and reducing heat loss.

[0062] According to the embodiments of the present disclosure, Figure 3 As shown, the pipe 117 is connected between the upper part of the flue gas duct 114 and the upper part of the furnace body 111, and the flue gas outlet 1131 of the outer flue 113 is located at the lower part of the outer furnace wall 112. In this way, the residence time of the flue gas in the flue gas duct 114 and the outer flue 113 can be extended, thereby improving the heat exchange efficiency.

[0063] In an illustrative embodiment, as shown in the figure, the furnace body 111 includes but is not limited to being configured as a cylindrical tube or a cubic tube structure.

[0064] In an exemplary embodiment, the outer furnace wall 112 can be built with refractory bricks and heat-insulating castables, and the furnace body 111 can be built with refractory heat-conducting materials. An annular outer flue 113 is formed between the furnace body 111 and the outer furnace wall 112 .

[0065] In an illustrative embodiment, the outer furnace wall 112 is constructed of silicon carbide refractory bricks and thermal insulation castables, and the exterior is a steel shell.

[0066] In an exemplary embodiment, the pipe 117 may be a heat-resistant steel pipe lined with a refractory material.

[0067] According to an embodiment of the present disclosure, a gas outlet (not shown) is provided at the upper portion of the furnace body 111 , which is suitable for allowing carbon monoxide (CO) gas generated by the gasification reaction between the gasification raw material (coal char) and the gasification agent (CO2) to be discharged.

[0068] According to the embodiments of the present disclosure, Figure 3 As shown, a discharge port 1113 is provided at the bottom of the furnace body 111 , and the discharge port 1113 is suitable for allowing ash and slag generated after the coal char is gasified to be discharged.

[0069] In an illustrative embodiment, coal char is in reverse contact with carbon dioxide under high temperature environment to produce a gasification reaction, and the generated target gas with CO as the main component is drawn out from the gas outlet at the upper part of the gasification channel, and the harmless ash produced by gasification is discharged through the discharge port 1113 at the bottom.

[0070] According to the embodiments of the present disclosure, Figure 3 As shown, the furnace body 111 further includes an air distribution plate 1114, which is obliquely installed between the periphery of the discharge port 1113 and the furnace body 111, so that an air chamber 1115 adjacent to the accommodation space 1111 is formed between the air distribution plate 1114 and the bottom wall and side wall of the furnace body 111. The carbon dioxide from the condenser enters the air chamber 1115 from the air inlet located at the lower part of the air chamber 1115, and enters the accommodation space 1111 through a plurality of through holes on the air distribution plate 1114, contacts the coal char in the accommodation space 1111, and causes the ash falling on the air distribution plate 1114 to be discharged through the discharge port 1113.

[0071] In such an embodiment, the pressure of the carbon dioxide gasifying agent can be stabilized through the gas chamber 1115, ensuring that the gasifying agent (i.e., CO2) can evenly pass through the through holes on the gas distribution plate 1114, and further cool the ash around the discharge port 1113, thereby ensuring that the temperature of the discharge port 1113 is controlled within a reasonable material use temperature range.

[0072] In an illustrative embodiment, Figure 3 As shown, the gas distribution plate 1114 may be a conical structure, made of heat-resistant steel. The bottom of the gas distribution plate 1114 is a discharge port 1113, which is connected to the outside and is a discharge channel for the ash after gasification.

[0073] In an illustrative embodiment, the gas distribution plate 1114 is provided with evenly distributed through holes, and the gas distribution plate 1114 is used to support ash and adjust the distribution of the gasifying agent so that the gasifying agent entering the containing space 1111 is evenly distributed.

[0074] In an exemplary embodiment, the angle between the gas distribution plate 1114 and the horizontal plane can be between 15 and 70 degrees (for example, 15 degrees, 20 degrees, 30 degrees, 45 degrees, 60 degrees or 70 degrees) to promote the flow of residue to the discharge port 1113 and improve the distribution of the gasification agent in the containing space 1111.

[0075] In such an embodiment, the gasifying agent passing through the gas distribution plate 1114 and the residue remaining after the gasification reaction with the coal char are reversely contacted and heat exchanged, the temperature of the residue is reduced, and the temperature of the gasifying agent is preheated to the gasification reaction temperature.

[0076] According to an embodiment of the present disclosure, the gasifier further includes an air supply assembly (not shown in the figure). The air supply assembly is configured to blow loose air toward the discharge port 1113 to prevent ash and slag from piling up at the discharge port 1113 .

[0077] In an illustrative embodiment, the gasifier further includes a valve (not shown in the figure), which cooperates with the loosening air component to allow or prevent the loosening air component from blowing loosening air toward the discharge port 1113 .

[0078] According to the embodiments of the present disclosure, Figure 3 As shown, baffles 116 are arranged in the smoke duct 114 and the outer smoke duct 113, so that the smoke flows along a serpentine path in the smoke duct 114 and the outer smoke duct 113, thereby extending the residence time of the smoke in the smoke duct 114 and the outer smoke duct 113.

[0079] In an exemplary embodiment, the baffle 116 may be made of heat-resistant steel.

[0080] According to an embodiment of the present disclosure, the furnace body 111 further includes a feed pipe 1112, which passes through the outer furnace wall 112 and is installed on the top of the furnace body 111 to communicate with the accommodation space 1111, wherein the coal char enters the accommodation space 1111 via the feed pipe 1112. The flue gas duct 114 is located below the feed pipe 1112, and the top of the flue gas duct 114 is configured to be conical, so that the coal char falling on the top of the flue gas duct 114 is evenly dispersed in the accommodation space 1111, which can prevent the raw materials from being concentrated, thereby ensuring that the gasification reaction in the entire accommodation space 1111 is more uniform, which helps to improve the gasification efficiency.

[0081] According to an embodiment of the present disclosure, the gasifier 11 further includes a tubular member 115. The tubular member 115 extends horizontally and is arranged below the flue gas duct 114, and is in communication with the flue gas duct 114. The tubular member 115 penetrates two opposite sides of the furnace body 111 to guide the flue gas into the flue gas duct 114. There are two burners 12, which are symmetrically arranged at both ends of the axial direction of the tubular member 115 to provide flue gas by burning fuel (for example, pyrolysis oil gas from the pyrolysis furnace and oxygen from the hydrogen production component).

[0082] In an alternative embodiment, the number of tubular members 115 can be multiple, and pairs of burners 12 are symmetrically arranged at both axial ends of the tubular member 115, suitable for providing flue gas by burning fuel (for example, pyrolysis oil gas from a pyrolysis furnace and oxygen from a hydrogen production component).

[0083] In an exemplary embodiment, the gasifier 11 further includes two tubular members 115, which are disposed perpendicularly to each other below the flue gas duct 114 and communicate with the flue gas duct 114. It is understandable that the flue gas supply assembly may also include 1 or 3 tubular members 115, and the specific number may be selected according to actual needs.

[0084] In an exemplary embodiment, a pair of burners 12 are disposed opposite to each other at both ends of each tubular member 115. Specifically, the combustion flame of each burner 12 is sprayed into the tubular member 115, so that the tubular member 115 has the function of a furnace, and the smoke generated by the combustion is also discharged from the tubular member 115 to the smoke pipe 114 and transported upward, thereby stably and evenly heating the coal char. The tubular member 115 includes but is not limited to being made of heat-resistant steel.

[0085] In an illustrative embodiment, an air inlet 1116 for allowing the gasification agent to enter is disposed at the bottom of the air chamber 1115 , and the air inlet 1116 is disposed parallel to and opposite to the smoke outlet 1131 and the burner 12 .

[0086] Figure 4 A partial cross-sectional view of a combustor according to an embodiment of the present disclosure is schematically shown.

[0087] According to the embodiments of the present disclosure, Figure 4 As shown, each burner 12 includes a central channel 121, a gas fuel channel 122, a solid fuel channel 123 and a combustion-supporting channel 124. The central channel 121 is suitable for providing primary air or oxygen into the tubular member 115. The gas fuel channel 122 is arranged at the periphery of the central channel 121, and is suitable for conveying gas fuel (for example, pyrolysis oil gas from a pyrolysis furnace) into the tubular member 115, so that the gas fuel and the primary air or oxygen are preliminarily burned at the end of the nozzle. The solid fuel channel 123 is arranged at the periphery of the gas fuel channel 122, and is suitable for conveying solid fuel into the tubular member 115. The combustion-supporting channel 124 is arranged at the periphery of the solid fuel channel 123, and is suitable for conveying secondary air or oxygen into the tubular member 115, so as to mix with the solid fuel under the temperature environment provided by the preliminary combustion, and fully burn to provide flue gas. Among them, both the primary oxygen and the secondary oxygen can be oxygen generated from the hydrogen production component 2.

[0088] In an alternative embodiment, the combustion of the fuel may be performed inside the burner 12 , and the high-temperature flue gas generated by the burner 12 may be sprayed into the tubular member 115 .

[0089] In such an embodiment, the tubular member 115 introduces the high-temperature flue gas into the flue duct 114. The high-temperature flue gas rises in the flue duct 114, enters the external flue 113 through the pipe 117, and is discharged from the flue outlet 1131. During the movement of the high-temperature flue gas, the heat is diffused into the containing space 1111 through the flue duct 114 on both sides of the containing space 1111 and the wall surface of the external flue 113. The multi-faceted radiation heat transfer method increases the heat transfer area, improves the heat supply per unit time, and reduces the lateral heat transfer radius between the gasification raw material and the heat source in the containing space 1111, thereby ensuring the radiation intensity of the heat source and being able to provide heat for the gasification process in a timely and stable manner.

[0090] In an illustrative embodiment, the burner 12 may be cylindrical, with a diameter of 200 to 400 mm, and adopt a four-channel design, including a central channel 121, a gas fuel channel 122, a solid fuel channel 123, and a combustion-supporting channel 124 from the inside to the outside. The width of each channel may be 10 to 50 mm in a circular ring shape. The nozzles at the end of the three outer channels narrow toward the central channel 121, forming a horizontal angle of 10 to 30 degrees, and each end of the channel (the end close to the tubular member 115) is protected by a cooling water jacket. The gas fuel is initially burned with the primary air / oxygen at the nozzle at the end of the burner 12 (the end extending into the tubular member 115), and then the solid fuel is fully burned with the secondary air / oxygen in the tubular member 115 to produce high-temperature flue gas.

[0091] In an illustrative embodiment, the smoke outlet 1131 is located below the burner 12, and the smoke outlet 1131 is arranged parallel to the burner 12. The waste smoke after heat exchange is discharged from the smoke outlet 1131, and the heat carried by the waste smoke can be reused downstream through waste heat utilization methods such as heat exchangers and dryers.

[0092] According to an embodiment of the present disclosure, the coal gasification component further includes a dryer. The dryer is suitable for drying the raw coal to obtain dried raw coal and water vapor, and the dried raw coal is transported to the pyrolysis furnace for pyrolysis, and the water vapor is transported to the hydrogen production component 2. The conveying pipeline passes through the dryer after passing through the pyrolysis furnace to provide a medium temperature environment for drying the raw coal, and the other end of the conveying pipeline is connected to the condenser to condense the flue gas after cooling.

[0093] In the process of implementing the present disclosure, it was found that the moisture generated during the drying process of 1 ton of coal (generally 5%~20%) and the moisture in the high-temperature flue gas (the hydrogen content of coal is about 10 percentage points) produce a total of about 250kg. The energy of the high-temperature flue gas is fully utilized, and the coal and water intakes are adjusted at the same time. As the water source for electrolysis of water, the consumption of external water is avoided, and the recycling of water within the light coal complementary methane production system with near zero carbon emissions is realized, saving water resources.

[0094] According to an embodiment of the present disclosure, the coal gasification assembly 1 involves processes such as drying, pyrolysis, coal char and CO2 gasification and combustion.

[0095] The raw coal first enters the dryer and indirectly exchanges heat with the medium-temperature flue gas from the pyrolysis furnace to remove moisture from the raw coal. The dried raw coal is further sent to the pyrolysis furnace, and under air-tight and medium-high temperature conditions (600-900°C), coal pyrolysis reaction occurs to generate high-temperature carbon-rich coal coke and hydrogen-rich pyrolysis oil and gas. The pyrolysis oil and gas are sent to the burner 12 and burned with the oxygen produced by the electrolysis of water by the hydrogen production component 2 to produce high-temperature flue gas (1000-1300°C) with CO2 and water vapor as the main components; while the solid-phase high-temperature coal coke enters the gasification furnace 11 and undergoes a gasification reaction with the CO2 gasification agent to generate CO; since the coal pyrolysis and the gasification reactions of coal coke and CO2 are all strongly endothermic reactions, the required heat is mainly provided by indirect heat transfer from the high-temperature flue gas (1000-1300°C) generated by the burner 12.

[0096] The high-temperature flue gas (1000-1300℃) provides the heat required for the gasification reaction of coal char and CO2 by indirect heating, and the generated medium-high temperature flue gas (700-1000℃) further indirectly heats the coal pyrolysis reaction, and then the obtained medium-temperature flue gas (300-500℃) is further used to dry the raw coal and remove the moisture in the coal. The obtained low-temperature flue gas (100-150℃) is separated into CO2 and water through a condenser, wherein CO2 is circulated to the gasifier 11 as a gasifying agent, and the water is used together with the water removed by coal drying as a water source for subsequent electrolysis of water to produce hydrogen.

[0097] According to the embodiments of the present disclosure, Figure 1 As shown, the hydrogen production assembly 2 includes an electrolyzer and a photovoltaic panel. The electrolyzer is suitable for receiving condensed water, and the photovoltaic panel is suitable for converting solar energy into electrical energy to electrolyze the condensed water in the electrolyzer.

[0098] According to the near-zero carbon emission light-coal complementary methane production system of the embodiment of the present disclosure, solar energy electrolysis of water is coupled to produce hydrogen, and the green hydrogen produced is subjected to a methanogenic reaction with the CO produced by the coal gasification component 1 to obtain methane. Through the light-coal complementary methane production system, the consumption of renewable energy is improved, the consumption of coal fossil energy is reduced, zero CO2 emissions are achieved, and environmental pollution is greatly reduced.

[0099] According to the embodiments of the present disclosure, Figure 1 As shown, the hydrogen production assembly 2 further includes a water purifier, which is suitable for filtering condensed water before entering the electrolyzer.

[0100] According to the embodiment of the present disclosure, the hydrogen production component 2 uses solar photovoltaic to generate electricity, and uses the condensed water produced by the coal gasification component 1 as the water source, and uses green electricity to drive the electrolysis of water to produce hydrogen and oxygen. Oxygen and high-temperature pyrolysis oil and gas are used for oxygen-enriched combustion, and the heat generated is used for coal pyrolysis and gasification reaction of coal char and CO2. Hydrogen and CO produced by the coal gasification component 1 generate methane through methanation reaction.

[0101] Figure 5 The composition diagram of the methanation assembly according to an embodiment of the present disclosure is schematically shown.

[0102] According to the embodiments of the present disclosure, Figure 5 As shown, the methanation component 3 includes a plurality of reactors 31 arranged in cascade. The plurality of reactors 31 arranged in cascade are suitable for causing the carbon monoxide from the gasifier 11 and the hydrogen from the hydrogen production component 2 to undergo a methanation reaction step by step under the action of a catalyst. According to the flow direction of carbon monoxide, a portion of the product gas produced by the reactor 31 located downstream is circulated to the reactor 31 located in the first stage through the circulation compressor 32 as a circulation gas to control the temperature of the reactor in the first stage, and the product gas may include methane and unreacted hydrogen and carbon monoxide.

[0103] According to the embodiments of the present disclosure, the ratio of H2 to CO in the synthesis gas can be adjusted to meet the requirements of the methanation reaction. In the methanation reactor 31, H2 and CO react to generate methane (CH4) in the reactor 31 under a certain temperature, pressure and catalyst. The methane, water and other gases (such as unreacted H2 and CO) in the methanation reaction product are separated to obtain a high-concentration methane (CH4) gas.

[0104] In an illustrative embodiment, Figure 4 As shown, the methanation component 3 also includes a desulfurization tank 33, which is used to desulfurize the raw gas of carbon monoxide from the gasifier 11 and hydrogen from the hydrogen production component 2. According to the near-zero carbon emission light coal complementary methane production system provided by the embodiment of the present disclosure, combined with the excellent characteristics of solar water electrolysis hydrogen production technology, a near-zero carbon emission light coal complementary methane production system has been developed. Solar power is used to generate electricity, and water is decomposed into hydrogen and oxygen by electrolysis, wherein the oxygen is fully burned with the pyrolysis oil and gas produced by the coal gasification component 1, and the released heat is supplied to the heat required for the pyrolysis of coal and the gasification reaction of coal char and CO2 to absorb heat, so that the coal char reacts with CO2 to generate CO, and the green H2 produced by the electrolysis of water undergoes a methanation reaction to obtain a methane product.

[0105] In an illustrative embodiment, the raw coal in the form of 0-30 mm crushed or 30-80 mm block is first transported to the dryer by a screw conveyor, and is indirectly heat exchanged with the medium-temperature flue gas (300-500°C) from the pyrolysis furnace to remove free moisture from the coal. The dried lump coal is further sent to the pyrolysis furnace, which can be a moving bed, fluidized bed, rotating bed, rotary kiln, etc. according to the characteristics of the coal raw material, and the coal pyrolysis reaction occurs under air-tight and medium- and high-temperature conditions (600-900°C) to generate high-temperature carbon-rich coal coke and hydrogen-rich pyrolysis oil gas. The pyrolysis oil gas is sent to the burner 12 to burn with the oxygen produced by photovoltaic electrolysis of water, producing high-temperature flue gas (1000-1300℃) with CO2 and water vapor as the main components; and the solid high-temperature coal char enters the gasifier 11 to react with the CO2 gasification agent to generate CO; since the coal pyrolysis and the gasification reaction of coal char and CO2 are both strongly endothermic reactions, the required heat is mainly provided by indirect heat transfer from the high-temperature flue gas (1000-1300℃) generated by the burner 12.

[0106] The high-temperature flue gas (1000-1300°C) provides the heat required for the gasification reaction of coal char and CO2 in an indirect heating manner, and the generated medium-high temperature flue gas (700-1000°C) further indirectly heats the coal pyrolysis reaction, and then the obtained medium-temperature flue gas (300-500°C) is further used to dry the raw coal and remove moisture from the coal, and the obtained low-temperature flue gas (100-150°C) is separated into CO2 and moisture through a condenser, wherein CO2 is circulated to the gasifier 11 as a gasifying agent, and the moisture together with the moisture obtained from coal drying is used as a water source for subsequent electrolysis of water to produce hydrogen.

[0107] The photovoltaic panel can be composed of multiple photovoltaic cells (for example, it can be silicon-based materials). When sunlight shines on the photovoltaic, the photons interact with the semiconductor materials in the photovoltaic panel to generate electron flow, thereby generating direct current (DC), which is then transmitted to the electrolyzer. The condensed water produced by the coal gasification component is used as the water source to fill the electrolyzer with water, and the operating temperature range is 25-80℃.

[0108] Green electricity (solar energy) drives water in alkaline electrolyzers to produce hydrogen and oxygen:

[0109] 2H2O=power on=2H2↑+O2↑.

[0110] Among them, the electrolytic cell is mainly composed of protective plates, plates, contact electrode plates, diffusion layers, membrane electrodes and other components. The electrolyte controlled to the set temperature by a constant temperature water bath is pumped to the liquid input port of the electrolytic cell, and then enters the microchannel in the plate and diffuses on the diffusion layer to form a uniform electrolyte film on the membrane electrode; the liquid film electrolysis in the anode area of ​​the membrane electrode generates O2, H+ and 2e, and the generated O2 is discharged from the electrolyte output port on the anode side, the generated H+ enters the cathode area through the exchange membrane, and the generated 2e is transferred to the cathode through the external circuit. The liquid film in the cathode area of ​​the membrane electrode plays the role of transferring H+ to the cathode, and H+ combines with 2𝑒 on the cathode to generate H2, which is discharged from the electrolyte output port on the cathode side.

[0111] The chemical equation for the gasification reaction of coal char and CO2 is:

[0112] CO + 3H2 → CH4 + H2O;

[0113] Among them, △H 298K =-206.28 kJ / mol. Normally, every 1% conversion of CO will produce a temperature rise of 74°C.

[0114] The methanation assembly 3 comprises three adiabatic fixed bed reactors 31 arranged in cascade, wherein the reactors are, in order of CO flow direction, a first stage reactor, a second stage reactor and a third stage reactor.

[0115] The first stage reactor and the second stage reactor are connected in series (or in series-parallel), and part of the product gas produced by the second reactor is used as circulating gas to control the bed temperature of the first reactor, and the circulating temperature is 60-150°C. The outlet temperature of the first reactor is about 650°C, and the outlet temperature of the second stage reactor is 500-650°C.

[0116] The heat is recovered by the steam superheater and waste boiler at the outlet of the first stage reactor 31 and the waste boiler at the outlet of the second stage reactor 31 to produce medium and high pressure superheated steam. The high concentration CH4 gas is discharged from the third stage reactor 31, and the unreacted mixed gas is recycled into the circulation compressor for reaction.

[0117] The methanation process requires that the raw gas modulus is slightly greater than 3 and the total sulfur content does not exceed 0.1×10 −6 A separate desulfurization tank 31 is provided to reduce the total sulfur in the raw gas (carbon monoxide from the gasifier 11 and hydrogen from the hydrogen production component 2) to 30×10 −9 The first stage reactor, the second stage reactor and the third stage reactor are filled with nickel-based or alumina catalysts.

[0118] For every ton of standard coal burned by a conventional industrial boiler, it is generally estimated that 2.66 to 2.72 tons of CO2 are produced, and the specific value depends on the coal quality and gasification conditions. After 1 ton of carbon is completely burned in oxygen, it can produce about 3.67 tons of CO2 (based on the ratio of carbon atomic weight to CO2 molecular weight). The near-zero carbon emission light coal complementary methane production system provided in the embodiment of the present disclosure decouples the traditional one-step coal gasification into a graded gasification process, pyrolyzes coal to produce coal char, realizes the cascade utilization and orderly conversion of coal chemical energy, and reduces the irreversible losses in the gasification process. By adjusting the amount of coal and the CO2 produced by the combustion of O2, and using CO2 as a gasifying agent, the natural enrichment of carbon components is achieved, a high concentration of CO can be obtained, and near-zero CO2 emissions are achieved.

[0119] The near-zero carbon emission light-coal complementary methane production system provided in the embodiments of the present disclosure produces oxygen through solar water electrolysis, and fully burns the high-temperature flue gas produced by the hydrogen-rich pyrolysis oil and gas produced in the coal pyrolysis process, and uses the cascaded utilization of the waste heat of the high-temperature flue gas to provide the required heat for the gasification reaction, pyrolysis, drying and other processes of coal char and CO2, thereby fully realizing the cascade utilization and full utilization of heat and greatly improving the energy utilization level of the system.

[0120] In the near-zero carbon emission light-coal complementary methane production system provided by the embodiment of the present disclosure, the cold gas efficiency of the graded gasification of the coal gasification component 1 reaches more than 85%, which is 8 to 10 percentage points higher than the traditional Texaco gasification technology. This improvement means that under the same raw coal consumption, the graded gasification technology coupled with the solar water electrolysis system can generate more CH4 with higher chemical energy, thereby improving the energy conversion efficiency and economic benefits of the entire gasification system.

[0121] The embodiments of the present disclosure are described above. However, these embodiments are only for illustrative purposes and are not intended to limit the scope of the present disclosure. Although the embodiments are described above separately, this does not mean that the measures in the various embodiments cannot be used in combination to advantage. The scope of the present disclosure is defined by the attached claims and their equivalents. Without departing from the scope of the present disclosure, those skilled in the art may make a variety of substitutions and modifications, which should all fall within the scope of the present disclosure.

Claims

1. A near-zero carbon emission light-coal complementary methane production system, characterized in that: include: Coal gasification components, suitable for gasifying raw coal to produce carbon monoxide; A hydrogen production component is used to electrolyze condensed water generated during the gasification of the raw coal to produce hydrogen; as well as The methanation component is suitable for causing the hydrogen produced by the hydrogen production unit and the carbon monoxide produced by the coal gasification component to undergo a methanation reaction to obtain methane.

2. The methane production system according to claim 1, characterized in that: The coal gasification assembly comprises: A pyrolysis furnace, adapted to pyrolyze the raw coal to produce coal char and pyrolysis oil and gas; A burner, adapted to burn the pyrolysis oil and gas with the aid of oxygen generated during the electrolysis process to obtain flue gas; a condenser, adapted to condense the flue gas and separate the condensed water and carbon dioxide; and A gasifier, adapted to use the carbon dioxide from the condenser as a gasifying agent to gasify the coal char from the pyrolysis furnace to produce the carbon monoxide, wherein the flue gas provides a high temperature environment for the coal char gasification reaction before condensation; Wherein, the flue gas provides a medium to high temperature environment for the raw coal to be pyrolyzed before condensation.

3. The methane production system according to claim 2, characterized in that: The gasifier comprises: A furnace body, forming a containing space inside; an outer furnace wall, arranged outside the furnace body and forming an outer flue with the furnace body; and A smoke duct is vertically installed in the accommodation space, and the upper part of the smoke duct is connected with the external flue through a pipe fitting; Among them, the burner is installed on the furnace body and is located below the flue gas duct. It is suitable for providing the flue gas to the flue gas duct from the bottom. The flue gas rises in the flue gas duct to heat the coal char flowing downward and the carbon dioxide flowing upward in the accommodating space, so that the coal char undergoes a gasification reaction. The cooled flue gas is discharged through the external flue and passes through the pyrolysis furnace through a conveying pipe to provide the medium and high temperature environment for the pyrolysis of the raw coal.

4. The methane production system according to claim 3, characterized in that: The furnace body also includes: a feed pipe, passing through the outer furnace wall and installed on the top of the furnace body to communicate with the accommodation space, wherein the coal char enters the accommodation space via the feed pipe; The flue gas duct is located below the feed duct, and the top of the flue gas duct is configured to be conical, so that the coal char falling on the top of the flue gas duct is evenly dispersed in the accommodation space.

5. The methane production system according to claim 3, characterized in that: The gasifier further comprises: A tubular member extending in a horizontal direction and arranged below the flue gas duct and communicating with the flue gas duct, wherein the tubular member penetrates two opposite sides of the furnace body to guide the flue gas into the flue gas duct; There are two burners, which are symmetrically arranged at two axial ends of the tubular member to provide the flue gas by burning fuel.

6. The methane production system according to claim 3, characterized in that: The bottom of the furnace body is provided with a discharge port, and the discharge port is suitable for allowing the ash generated by the coal char after the gasification reaction to be discharged; The furnace body also includes: An air distribution plate is obliquely installed between the periphery of the discharge port and the furnace body, so that an air chamber adjacent to the accommodation space is formed between the air distribution plate and the bottom wall and side wall of the furnace body; Among them, the carbon dioxide from the condenser enters the air chamber from the air inlet located at the lower part of the air chamber, and enters the containing space through multiple through holes on the air distribution plate, contacts the coal char in the containing space, and makes the ash falling on the air distribution plate be discharged through the discharge port.

7. The methane production system according to claim 3, characterized in that: The coal gasification assembly further comprises: A dryer, adapted to dry the raw coal to obtain dried raw coal and water vapor, and to transport the dried raw coal to the pyrolysis furnace for pyrolysis, and to transport the water vapor to the hydrogen production component; The conveying pipeline passes through the dryer after passing through the pyrolysis furnace to provide a medium-temperature environment for drying the raw coal, and the other end of the conveying pipeline is connected to the condenser to condense the flue gas after cooling.

8. The methane production system according to any one of claims 1 to 7, characterized in that: The hydrogen production component comprises: an electrolytic cell adapted to receive the condensed water; and The photovoltaic panel is suitable for converting solar energy into electrical energy to electrolyze the condensed water in the electrolytic cell.

9. The methane production system according to claim 8, characterized in that: The hydrogen production assembly also includes: A water purifier is used to filter the condensed water before it enters the electrolytic cell.

10. The methane production system according to any one of claims 1 to 7, characterized in that: The methanogenation assembly comprises: A plurality of reactors arranged in cascade are adapted to cause the carbon monoxide from the gasifier and the hydrogen from the hydrogen production assembly to undergo the methanogenic reaction step by step under the action of a catalyst; Wherein, according to the flow direction of the carbon monoxide, the product gas produced by the reactor located downstream is used as circulating gas to control the temperature of the reactor located in the first stage, and the product gas includes the methane and unreacted hydrogen and carbon monoxide.

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