Device for producing fuel gas by recovering low-grade waste heat

Abstract

The utility model provides a device for producing fuel gas through low-grade waste heat recovery. The device comprises a waste heat steam generator, a fuel gas generator and a combustor. The waste heat steam generator is arranged at a smoke outlet of original heat extraction equipment, external feed water is input into the evaporation assembly through the inlet header, water is subjected to heat transfer evaporation through the evaporation assembly and subjected to steam-water separation through the outlet header, and then steam is output to the fuel gas generator. The fuel gas generator comprises a fuel gas reaction chamber, biomass charcoal enters the fuel gas reaction chamber through a rotary sealing feeding valve and makes contact with water vapor entering the fuel gas reaction chamber, after the fuel gas reaction chamber is electrically heated to reach the set temperature, the water vapor reacts with the biomass charcoal to generate combustible gas hydrogen and carbon monoxide, and the combustible gas is output to the combustor through a combustible gas outlet to be combusted. And the combustor is arranged on the original heat extraction equipment, so that low-grade waste heat energy recovery is realized, and the waste heat utilization efficiency is improved.

Description

Technical Field

[0001] The present application relates to the field of waste heat recovery technology, and in particular to a device for recovering low-grade waste heat to produce gas. Background Art

[0002] Industrial enterprises use thermal equipment such as boilers, kilns, and heating furnaces in their production activities, which emit a large amount of waste heat from flue gases. Because this waste heat is relatively low in temperature (below 160°C), and its quality is low, and there is no way to return the recovered heat to the source (furnace or kiln), it is directly released into the atmosphere, wasting energy and polluting the environment. Therefore, further research is needed in this field to address this issue, focusing on how to further utilize this waste heat, improve resource utilization, and reduce environmental pollution. Utility Model Content

[0003] The purpose of the embodiments of the present application is to provide a device for recovering low-grade waste heat to produce gas, so as to further utilize the low-grade waste heat, improve resource utilization, and reduce environmental pollution.

[0004] In order to achieve the above objectives, the embodiments of the present application are implemented in the following manner:

[0005] The embodiment of the present application provides a device for recovering low-grade waste heat to produce gas, including a waste heat steam generator, a gas generator and a burner; the waste heat steam generator is arranged at the exhaust port of the original heat exhaust equipment, and has an inlet header, an evaporation component and an outlet header, water is input to the evaporation component through the inlet header, water is evaporated by heat transfer through the evaporation component, steam and water are separated in the outlet header, the separated water vapor is output to the gas generator, and the separated water flows back to the inlet header for recirculation; the gas generator includes a gas reaction chamber and a rotary sealed feed valve arranged at the upper end of the gas reaction chamber, a rotary sealed slag discharge valve at the lower end, a steam inlet chamber arranged around the gas reaction chamber, and a steam heating plate arranged outside the steam inlet chamber Tube, an electric heating device is arranged outside the coil, the outermost layer is provided with an insulation layer, a gas outlet pipe is arranged in the middle of the gas reaction chamber, biomass charcoal enters the gas reaction chamber through a rotary sealed feed valve, and water vapor enters the gas reaction chamber through a water vapor inlet. After the electrically heated gas reaction chamber reaches the set temperature, the water vapor and biomass charcoal in the gas reaction chamber are heated and activated, and react to generate combustible gases hydrogen and carbon monoxide. The combustible gas is output to the burner through the gas outlet pipe for combustion, and the carbon residue in the gas reaction chamber is discharged through the rotary sealed slag valve; the burner is arranged on the original heat exhaust equipment, and directly burns the combustible gas transported by the gas outlet pipe, so as to realize heat energy recovery and improve the utilization efficiency of waste heat.

[0006] Furthermore, the water vapor and biochar in the gas reaction chamber are heated and activated to react and generate combustible gases hydrogen and carbon monoxide. The reaction formula is:

[0007]

[0008] Among them, H2O↑ is water vapor, C is carbon, the reaction conditions are heating to 800-850℃, H2↑ is hydrogen, and CO↑ is carbon monoxide.

[0009] Furthermore, the waste heat steam generator includes a flue gas chamber, the exhaust port of the original heat exhaust equipment is connected to the flue gas chamber, and the waste heat of the flue gas entering the flue gas chamber through the exhaust port is heat exchanged with the evaporation component arranged in the flue gas chamber.

[0010] Furthermore, the evaporation component includes a plurality of spiral fin tubes connected by elbows to form a spiral fin tube group, and the spiral fin tube group is staggered and arranged to be horizontally flushed with the flue gas.

[0011] Furthermore, the smoke chamber is designed to be narrow at both ends and wide in the middle, which facilitates the arrangement of the required heating surface.

[0012] Furthermore, the gas reaction chamber is an internal space of a cylindrical tube wall, the upper end of the internal space of the tube wall is a rotary sealed feed valve, and the lower end is a rotary sealed slag discharge valve.

[0013] Furthermore, a water vapor inlet chamber communicating with the inner space of the tube wall is provided on the outer ring of the cylindrical tube wall, and a plurality of steam holes are provided on the wall surface of the cylindrical tube wall for supplying water vapor into the inner space of the tube wall.

[0014] Furthermore, a gas collecting pipe is provided at the center of the inner space of the tube wall, and a plurality of small holes are provided on the surface of the gas collecting pipe to communicate with the inner space of the tube wall.

[0015] Furthermore, a steam heating coil is provided outside the steam inlet chamber, and a heat insulation layer is provided outside the coil.

[0016] Furthermore, the electric heat source may adopt resistance heating or variable frequency heating.

[0017] Beneficial effects:

[0018] 1. The device for recovering low-grade waste heat and producing gas provided in the present application comprises a waste heat steam generator arranged at the exhaust port of the original heat exhaust equipment, and having an inlet header, an evaporation component and an outlet header. Water is input to the evaporation component through the inlet header, and the water evaporates through heat transfer in the evaporation component. After the evaporated steam and water are separated in the outlet header, the water vapor is output to the gas generator, and the separated water flows back to the inlet header for recirculation. The gas generator comprises a gas reaction chamber and a rotary sealed feed valve arranged at the upper end chamber of the gas reaction chamber and a rotary sealed slag discharge valve at the lower end. A steam inlet chamber is arranged outside the gas reaction chamber, a steam heating coil is arranged outside the steam inlet chamber, an electric heating device is arranged outside the coil, and a gas outlet pipe is arranged in the middle of the gas reaction chamber. Biochar enters the gas reaction chamber through a rotary sealed feed valve, and water vapor enters the gas reaction chamber through a water vapor inlet. After the electrically heated gas reaction chamber reaches the set temperature, the water vapor in the gas reaction chamber heats and activates the biochar, reacting to generate combustible gases hydrogen and carbon monoxide. The combustible gases are output to the burner through a gas outlet pipe, and the carbon residue in the gas reaction chamber is discharged through a rotary sealed slag valve. The burner is set on the original heat exhaust equipment to burn the combustible gas transported by the gas outlet pipe to achieve heat recovery and improve the efficiency of waste heat utilization. In this way, the waste heat of flue gas can be effectively recovered, and combined with biochar (such as straw, branches, fruit shells, waste wood, sawdust, etc., which are made into biochar through biomass tubular cracking), combustible gas can be prepared to produce high calorific value gas, thereby improving the efficiency of waste heat utilization, reducing environmental pollution, and providing farmers with some ways to increase their income (such as providing raw materials for the preparation of biochar, etc.).

[0019] 2. When the water vapor and charcoal recovered from waste heat are heated to 800-850℃, that is, C+H2O (water vapor)→H2+CO, H2 and CO are both combustible gases. At this time, the quality of the gas is also higher. The combustible gases (H2 and CO) can be directly sent to boilers, kilns, heating furnaces, etc. for combustion through their own pressure difference. For example, the exhaust temperature of thermal power station boilers in industrial areas is generally 150-160℃. After adding this device, the generated steam reacts with the charcoal in the gas generator to generate H2 and CO gas. The device's own power (pressure difference) is used to directly send them to the boiler furnace for combustion, eliminating the intermediate gas compression, cooling, storage and other processing processes, thereby saving costs and fuel and achieving the purpose of waste heat recovery.

[0020] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments of the present application. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work.

[0022] Figure 1 Schematic diagram of an apparatus for recovering low-grade waste heat to produce gas provided in an embodiment of the present application.

[0023] Figure 2 Schematic diagram of the waste heat steam generator.

[0024] Figure 3 This is a cross-sectional schematic diagram of the evaporation component in the waste heat steam generator, which is fixed on the tube sheet with multiple groups of spiral fin tubes arranged in a staggered manner.

[0025] Figure 4 Schematic diagram of the gas generator.

[0026] Icons: 10-Device for recovering low-grade waste heat to produce gas; 11-Waste heat steam generator; 111-Inlet header; 112-Outlet header; 113-Evaporation assembly; 1131-Spiral finned tube; 1132-Elbow; 1133-Tube sheet; 114-Insulation layer; 12-Gas generator; 121-Gas reaction chamber; 122-Rotary seal feed valve; 123-Rotary seal slag valve; 124-Water vapor inlet; 1241-Valve; 125-Gas outlet pipe; 126-Cylindrical tube wall; 127-Water vapor inlet chamber; 1271-Steam heating coil; 128-Insulation layer; 13-Burner; 131-Smoke exhaust port. DETAILED DESCRIPTION

[0027] The technical solutions in the embodiments of the present application will be described below in conjunction with the drawings in the embodiments of the present application.

[0028] See also Figure 1 , Figure 1 Schematic diagram of the low-grade waste heat recovery and production gas device 10 provided in the embodiment of the present application. In this embodiment, the low-grade waste heat recovery and production gas device 10 may include a waste heat steam generator 11, a gas generator 12 and a burner 13. Figure 1 A schematic diagram is given in .

[0029] In this embodiment, the waste heat steam generator 11 is arranged at the smoke exhaust port 131 of the original heat exhaust equipment, and has an inlet header 111, an evaporation component 113 and an outlet header 112. The feed water is input to the evaporation component 113 through the inlet header 111, and the water evaporates through heat transfer in the evaporation component 113. After the evaporated steam and water are separated in the outlet header 112, the water vapor is output to the gas generator 12, and the separated water flows back to the inlet header 111 for recirculation.

[0030] See also Figure 2 and Figure 3 , Figure 2 is a schematic diagram of the waste heat steam generator 11, Figure 3 It is a cross-sectional schematic diagram showing that the evaporation assembly 113 in the waste heat steam generator 11 is fixed on the tube plate 1133 with multiple groups of spiral fin tubes arranged in a staggered manner.

[0031] Exemplarily, the waste heat steam generator 11 includes a flue gas channel, and the exhaust port 131 of the original heat exhaust equipment is connected to the evaporator. The waste heat of the flue gas entering the flue gas chamber through the exhaust port 131 is heat-exchanged with the evaporation component 113 arranged in the flue gas chamber, and the recovered low-grade waste heat is converted into low-pressure steam. After water vapor separation in the outlet header 112, the water vapor is output to the gas generator 12, and the separated water flows back to the inlet header 111 for recirculation.

[0032] The evaporator assembly 113 comprises multiple spiral finned tubes 1131 connected by elbows 1132 to form a spiral finned tube assembly. These finned tubes are arranged in a staggered pattern, oriented transversely to the flue gas. The number of spiral finned tube assemblies can be tailored to the specific waste heat requirements, and the finned tube assemblies can be arranged on a tube sheet 1133 to form a flue gas flow channel.

[0033] For example, the flue gas channel is designed to be narrow at both ends and wide in the middle, and the cross-sectional width inside the flue gas chamber is larger than the inlet width and outlet width of the flue gas chamber. Combined with the layout of the spiral fin tube group, it can be heated more evenly to improve the conversion efficiency.

[0034] Please refer again Figure 1The gas generator 12 includes a gas reaction chamber 121 and a rotary sealed feed valve 122, a rotary sealed slag valve 123, a water vapor inlet 124, and a gas outlet pipe 125 arranged in the gas reaction chamber 121. The biochar enters the gas reaction chamber 121 through the rotary sealed feed valve 122, and the water vapor enters the steam heating coil 1271 through the water vapor inlet 124, enters the steam inlet chamber 127, and enters the gas reaction chamber 121 through the wall hole. After the electrically heated gas reaction chamber 121 reaches the set temperature, the water vapor and biochar in the gas reaction chamber 121 are heated and activated to react to generate combustible gases hydrogen and carbon monoxide. The combustible gas is output to the burner 13 through the gas outlet pipe 125, and the combustible gas transported from the gas outlet pipe 125 is burned. The carbon residue in the gas reaction chamber 121 is discharged through the rotary sealed slag valve 123.

[0035] The water vapor and biochar in the gas reaction chamber 121 are heated and activated to react and generate combustible gases hydrogen and carbon monoxide. The reaction formula is:

[0036]

[0037] Among them, H2O↑ is water vapor, C is carbon, the reaction conditions are heating to 800-850℃, H2↑ is hydrogen, and CO↑ is carbon monoxide.

[0038] See also Figure 4 , Figure 4 Schematic diagram of the gas generator 12.

[0039] Exemplarily, the gas reaction chamber 121 is an internal space of a tube wall formed by a cylindrical tube wall 126, the upper end of the internal space of the tube wall is a rotary sealed feed valve 122 (the biochar enters the gas reaction chamber 121 and moves from top to bottom under its own gravity), and the lower end of the internal space of the cylindrical tube wall 126 is a rotary sealed slag valve 123 (the charcoal residue in the gas reaction chamber 121 can be discharged through the rotary sealed slag valve 123).

[0040] A steam inlet chamber 127 is provided on the outer ring of the cylindrical tube wall 126 , and a plurality of steam holes are provided on the wall surface of the cylindrical tube wall 126 to allow steam to enter the inner space of the tube wall, thereby ensuring that the water vapor contacts and reacts with the charcoal.

[0041] A gas collecting pipe is provided at the center of the inner space of the pipe wall. A plurality of small holes are provided on the surface of the gas collecting pipe to communicate with the inner space of the pipe wall, thereby realizing the collection and output of gas.

[0042] A steam heating coil 1271 (coiled around the outer wall of the steam inlet chamber 127 ) is provided on the periphery of the steam inlet chamber 127 . After heating, the steam enters the steam inlet chamber 127 from the inlet of the steam inlet chamber 127 .

[0043] The electric heat source is arranged on the periphery of the coil, and the electric heat source can adopt resistance heating or variable frequency heating. The heat insulation layer 128 is arranged on the periphery of the electric heating device.

[0044] Operating principle: When thermal equipment such as boilers, kilns, and heating furnaces are working, the low-grade waste heat they generate (i.e., a large amount of flue gas waste heat) passes through the exhaust port 131 of the original heat exhaust equipment and the waste heat steam generator 11. The flue gas is heat-exchanged through the evaporation component 113 (such as a spiral fin tube group) to achieve heating of the evaporation component 113. The water entering the evaporation component 113 through the inlet header 111 is heated to form low-pressure steam (containing water vapor and water) and is gradually transported upward along the spiral fin tube group to the outlet header 112. After steam and water are separated in the outlet header 112, the water vapor is output to the gas generator 12, and the separated water flows back to the inlet header 111 for recirculation. The biochar enters the gas reaction chamber 121 through the rotary sealed feed valve 122, and the water vapor enters the steam inlet chamber 127 of the gas reactor through the water vapor inlet 124. A plurality of steam holes are provided on the wall of the cylindrical tube wall 126, and the steam enters the internal space 121 of the tube wall. When the gas reaction chamber 121 is heated by an electric heat source (such as resistance heating or frequency conversion heating) to reach the set temperature, the water vapor and biochar in the gas reaction chamber 121 are activated by heating and react to generate combustible gases hydrogen and carbon monoxide, which are output to the burner 13 through the gas outlet pipe 125 for combustion, and the carbon residue in the gas reaction chamber 121 can be discharged through the rotary sealed slag discharge valve 123.

[0045] In summary, the embodiment of the present application provides a device 10 for recovering low-grade waste heat to produce gas. The waste heat steam generator 11 is arranged at the exhaust port 131 of the original heat exhaust equipment, and has an inlet header 111, an evaporation component 113 and an outlet header 112. The feed water is input to the evaporation component 113 through the inlet header 111, and the water evaporates through the evaporation component 113. After the steam and water are separated through the outlet header 112, the water vapor is output to the gas generator 12, and the separated water flows back to the inlet header 111 for recirculation; the gas generator 12 includes a gas reaction chamber 121 and a rotary sealed feed valve 122 arranged at the upper end of the gas reaction chamber 121, a rotary sealed slag discharge valve 123 at the lower end, water vapor enters the steam inlet chamber 127 and the steam heating coil 1271 arranged outside the steam inlet chamber through the inlet 124, the steam coil is provided with an electric heating device, and the periphery is insulated. Biochar enters the gas reaction chamber 121 through the rotary sealed feed valve 122, and water vapor enters the gas reaction chamber 121 through the water vapor inlet 124. After the electrically heated gas reaction chamber 121 reaches the set temperature, the water vapor in the gas reaction chamber 121 and the biochar are activated by heating and react to generate combustible gases hydrogen and carbon monoxide. The combustible gases are output to the burner 13 through the gas outlet pipe 125, and the carbon residue in the gas reaction chamber 121 is discharged through the rotary sealed slag valve 123; the burner 13 burns the combustible gas delivered by the gas outlet pipe 125, so that the flue gas waste heat can be effectively recovered. Combustible gas is prepared by preparing combustible gas to produce high calorific value gas, thereby improving the efficiency of waste heat utilization, reducing environmental pollution, and providing some income for farmers (such as providing raw materials for the preparation of biochar).

[0046] When the water vapor recovered from waste heat and the charcoal are heated to 800-850°C, that is, C+H2O (water vapor)→H2+CO, H2 and CO are both combustible gases, and the quality of the gas is also relatively high at this time. The combustible gases (H2 and CO) can be directly sent to boilers, kilns, and heating furnaces for combustion through their own pressure difference. For example, the exhaust gas temperature of the thermal power station boiler in the industrial area is generally 150-160°C. After adding this device, the generated steam reacts with the charcoal in the gas generator 12 to generate H2 and CO gas, which is directly sent to the boiler furnace for combustion using the device's own power (pressure difference), eliminating the intermediate compression, cooling, storage and other processing processes of the gas, thereby saving costs and fuel and achieving the purpose of recovering waste heat.

[0047] The above description is merely an embodiment of the present application and is not intended to limit the scope of protection of the present application. For those skilled in the art, various modifications and variations of the present application are possible. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application shall be included in the scope of protection of the present application.

Claims

1. A device for recovering low-grade waste heat to produce gas, characterized in that: Including waste heat steam generator, gas generator and burner, The waste heat steam generator is installed at the exhaust port of the original heat exhaust equipment, and has an inlet header, an evaporation component and an outlet header. Water is input to the evaporation component through the inlet header, and the water evaporates through heat transfer in the evaporation component. After the evaporated steam and water are separated in the outlet header, the water vapor is output to the gas generator, and the separated water flows back to the inlet header for recirculation. The gas generator includes a gas reaction chamber and a rotary sealed feed valve arranged at the upper end of the gas reaction chamber and a rotary sealed slag valve at the lower end. A steam inlet chamber, a steam heating coil and an electric heating device are arranged outside the gas reaction chamber. Biochar enters the gas reaction chamber through the rotary sealed feed valve, and water vapor enters the gas reaction chamber through the water vapor inlet. After the electrically heated gas reaction chamber reaches a set temperature, the water vapor and biochar in the gas reaction chamber are heated and activated to react to generate combustible gases hydrogen and carbon monoxide. The combustible gas is output to the burner through a gas outlet pipe, and the carbon residue in the gas reaction chamber is discharged through the rotary sealed slag valve. The burner is arranged on the original heat exhaust equipment to burn the combustible gas transported by the gas outlet pipe, thereby recovering the waste heat and improving the waste heat utilization efficiency.

2. The device for recovering low-grade waste heat to produce gas according to claim 1, characterized in that: The water vapor and biochar in the gas reaction chamber are heated and activated to react and generate combustible gases hydrogen and carbon monoxide. The reaction formula is: Among them, H2O↑ is water vapor, C is carbon, the reaction conditions are heating to 800-850℃, H2↑ is hydrogen, and CO↑ is carbon monoxide.

3. The device for recovering low-grade waste heat to produce gas according to claim 1, characterized in that: The waste heat steam generator includes a flue gas chamber. The exhaust port of the original heat exhaust equipment is connected to the flue gas chamber. The waste heat flue gas entering the flue gas chamber through the exhaust port exchanges heat with the evaporation component arranged in the flue gas chamber.

4. The device for recovering low-grade waste heat to produce gas according to claim 3, characterized in that: The evaporation component includes a plurality of spiral fin tubes connected by elbows to form a spiral fin tube group. The spiral fin tube group is staggered and arranged so as to be horizontally flushed with the flue gas.

5. The device for recovering low-grade waste heat to produce gas according to claim 4, characterized in that: The smoke chamber is designed to be narrow at both ends and wide in the middle: the cross-sectional width inside the smoke chamber is greater than the inlet width and outlet width of the smoke chamber.

6. The device for recovering low-grade waste heat to produce gas according to claim 1, characterized in that: The gas reaction chamber is an inner space formed by a cylindrical tube wall, the upper end of the inner space of the tube wall is a rotary sealed feed valve, and the lower end is a rotary sealed slag discharge valve.

7. The device for recovering low-grade waste heat to produce gas according to claim 6, characterized in that: A steam inlet chamber is set on the outer ring of the pipe wall, and a plurality of steam holes are opened on the wall surface of the pipe wall to supply water vapor into the internal space of the pipe wall.

8. The device for recovering low-grade waste heat to produce gas according to claim 7, characterized in that: A gas collecting pipe is provided at the center of the inner space of the pipe wall, and a plurality of small holes are provided on the surface of the gas collecting pipe to communicate with the inner space of the pipe wall.

9. The device for recovering low-grade waste heat to produce gas according to claim 7, characterized in that: A steam inlet chamber is arranged outside the steam reaction chamber.

10. The device for recovering low-grade waste heat to produce gas according to claim 7, characterized in that: A steam heating coil is installed outside the steam inlet chamber.

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