Ammonia fuel porous medium combustion system and combustion method

Abstract

The application discloses an ammonia fuel porous medium combustion system and a combustion method, and belongs to the technical field of combustion equipment.The ammonia fuel porous medium combustion system comprises a heating furnace, a combustion assembly and a gas mixing box.The heating furnace is internally provided with a heating cavity.The combustion assembly comprises a porous medium burner, a premixed gas uniform distribution chamber and a combustion gas nozzle.The porous medium burner is located in the heating cavity, and the porous medium burner is formed with combustion holes.The premixed gas uniform distribution chamber is connected to the gas inlet side of the porous medium burner, and the premixed gas uniform distribution chamber is communicated with the plurality of combustion holes.The combustion gas nozzle is located on the side of the porous medium burner.The gas mixing box is provided with a gas inlet, a first combustion gas inlet and a premixed gas outlet.The premixed gas outlet and the premixed gas uniform distribution chamber are interconnected.The air outlet end of the combustion air blower is respectively communicated with the first combustion gas inlet and the initial end of the combustion gas nozzle through pipelines.The combustion efficiency of ammonia gas is greatly improved through the secondary combustion, the flammable range of ammonia gas is widened, the heating production efficiency of the workpiece is improved, and the production energy consumption is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to a combustion system, in particular to an ammonia fuel porous medium combustion system and a combustion method. BACKGROUND

[0002] The current heating furnace has large energy consumption, for example, an aluminum rod heating furnace. In order to reduce carbon emissions, some production equipment currently uses ammonia as fuel for heating. Ammonia is considered an important development direction for alternative fuels because its combustion products do not contain carbon dioxide and its storage and transportation process is mature. However, ammonia has a narrow flammable limit and low combustion efficiency when burning, which limits the application and development of ammonia fuel. Therefore, there is an urgent need for a combustion system that has higher combustion efficiency for ammonia fuel. SUMMARY

[0003] The present application aims to provide an ammonia fuel porous medium combustion system and a combustion method to solve one or more technical problems in the prior art and at least provide a beneficial choice or create conditions.

[0004] The solution to the technical problem of the present application is:

[0005] An ammonia fuel porous medium combustion system, comprising: a heating furnace, an internal heating cavity is provided; a combustion assembly, comprising a porous medium burner, a premixed gas uniform distribution chamber and a combustion gas nozzle, the porous medium burner is located in the heating cavity, the gas outlet side of the porous medium burner faces the inside of the heating cavity, the premixed gas uniform distribution chamber is connected to the gas inlet side of the porous medium burner, the premixed gas uniform distribution chamber is communicated with a plurality of combustion holes, the combustion gas nozzle is located beside the porous medium burner, the end of the combustion gas nozzle extends to the gas outlet side of the porous medium burner and is bent towards the gas outlet direction close to the porous medium burner; a gas mixing box is provided with a gas inlet, a primary combustion gas inlet and a premixed gas outlet, the premixed gas outlet and the premixed gas uniform distribution chamber are interconnected; a combustion air fan, the air outlet end of the combustion air fan is respectively communicated with the primary combustion gas inlet and the beginning of the combustion gas nozzle through a pipeline.

[0006] The technical scheme has at least the following beneficial effects: the workpiece needing to be heated is sent into the heating cavity, and the workpiece is heated by the combustion assembly when passing through the combustion assembly. Specifically, ammonia gas is input from the gas inlet into the mixing box, the combustion-supporting fan outputs combustion-supporting gas from the outlet end through the pipeline to the mixing box, the ammonia gas and the combustion-supporting gas are mixed in the mixing box, and then the mixed gas is output from the premixed gas outlet to the porous medium burner to be combusted in the plurality of combustion holes of the porous medium burner. The porous medium burner widens the flammable range, improves the combustion efficiency, makes the flame temperature more uniform, reduces the local high-temperature area, and reduces the pollutant emission. The first-stage combustion can be maintained under the fuel-rich condition to ensure that the nitrogen oxide is generated in the combustion area. The combusted gas is discharged into the heating cavity to heat the workpiece on the gas outlet side. Meanwhile, the combustion-supporting fan outputs the combustion-supporting gas from the combustion-supporting gas nozzle through the pipeline to the gas outlet side of the porous medium burner along the bending of the combustion-supporting gas nozzle. The combustion-supporting air is supplemented to the combusted gas to further combust the flammable gas on the gas outlet side of the porous medium burner to realize the second-stage combustion. The unburned ammonia gas in the first-stage combustion is consumed at a lower equivalence ratio. In this way, the nitrogen oxide emission can be effectively controlled when the ammonia gas is used for combustion heating. The second-stage combustion greatly improves the combustion efficiency of the ammonia gas, widens the flammable range of the ammonia gas, improves the heating production efficiency of the workpiece, reduces the production energy consumption, ensures the stable and uniform combustion of the ammonia gas, and improves the production stability and efficiency of the ammonia fuel system for heating the workpiece.

[0007] As a further improvement of the above technical scheme, the outer side of the premixed gas uniform distribution chamber is provided with a second-stage combustion-supporting air distribution box, the second-stage combustion-supporting air distribution box extends around the porous medium burner, a plurality of combustion-supporting gas nozzles are connected to one side of the second-stage combustion-supporting air distribution box around the porous medium burner, the plurality of combustion-supporting gas nozzles can rotate and be positioned along the axis parallel to the gas outlet direction of the porous medium burner, and the outlet end of the combustion-supporting fan is connected to the second-stage combustion-supporting air distribution box through the pipeline. The combustion-supporting gas enters the second-stage combustion-supporting air distribution box, is distributed to a plurality of premixed gas uniform distribution chambers, and the plurality of combustion-supporting gas nozzles blow out the combustion-supporting gas on the gas outlet side of the porous medium burner to strengthen the mixing of the second-stage combustion-supporting air and the first-stage combustion tail gas, make the unburned ammonia gas and the second-stage combustion-supporting air quickly and fully contact to combust, and make the second-stage combustion-supporting air more uniformly distributed to better supplement the combustion-supporting air to the combusted gas and further improve the combustion efficiency.

[0008] As a further improvement of the above technical solution, the space in the premixed gas uniform distribution chamber gradually increases in the direction close to the porous medium burner. After the mixed gas is input from the end of the premixed gas uniform distribution chamber with smaller internal space, the mixed gas gradually diffuses to the porous medium burner due to the gradual increase of the internal space of the premixed gas uniform distribution chamber in the direction close to the porous medium burner, and the speed of the mixed gas entering the porous medium burner is reduced, so that the mixed gas enters the plurality of combustion holes more uniformly, and the uniformity of the temperature distribution of the porous medium burner is improved.

[0009] As a further improvement of the above technical solution, the application further comprises a circulating fan and a preheating box, the preheating box is located in the heating cavity away from the combustion assembly side, a plurality of preheating pipes are connected to the preheating box along the length direction of the heating cavity, a plurality of preheating holes are arranged on the plurality of preheating pipes respectively, the air outlet end of the circulating fan is connected to the side of the preheating box away from the combustion assembly through a pipeline, and the air inlet end of the circulating fan is connected to the heating cavity. The air inlet end of the circulating fan draws flue gas from the heating cavity, and blows the flue gas into the preheating box through the pipeline. After the flue gas enters the preheating box, it can be distributed to a plurality of preheating pipes connected to the preheating box, and then reflows into the space of the heating cavity away from the combustion assembly through the preheating holes on the preheating pipes. The workpiece can enter from the side of the heating cavity provided with the preheating box, and the flue gas is used to preheat the workpiece first, so that the heat utilization rate of the flue gas is improved, the heating speed of the workpiece is improved, and the production energy consumption is further reduced.

[0010] As a further improvement of the above technical solution, a heat exchange pipe is arranged in the preheating box, one end of the heat exchange pipe is connected to the air outlet end of the combustion-supporting fan through a pipeline, and the other end of the heat exchange pipe is connected to the primary combustion-supporting gas inlet through a pipeline. The air outlet end of the combustion-supporting fan inputs combustion-supporting gas to the heat exchange pipe through a pipeline, and the flue gas exchanges heat with the heat exchange pipe when flowing in the preheating box. In this way, the combustion-supporting gas is first preheated and heated by the flue gas, and then enters the mixing box for mixing, so that the initial temperature of the mixed gas is improved, which is beneficial to improve the ammonia gas combustion temperature and more fully recycle the heat of the flue gas.

[0011] As a further improvement of the above technical solution, a denitration device is arranged in the preheating box. When the flue gas flows in the preheating box, the nitrogen oxides in the flue gas react with the residual ammonia in the flue gas and the supplementary sprayed ammonia under the action of the medium-temperature catalyst in the denitration device, and the nitrogen oxides are reduced to nitrogen. In this way, the pollution caused by the combustion exhaust gas can be effectively reduced.

[0012] As a further improvement of the above technical solution, the heat exchange pipes are arranged on both sides of the denitration device along the length direction of the heating cavity in the preheating box. The flue gas flows in the preheating box and passes through a heat exchange pipe before entering the denitration device, so that the heat in the flue gas can be recovered once, and the flue gas can be better controlled to reach a suitable temperature range when entering the denitration device. The flue gas after the denitration device passes through the heat exchange pipe again for heat exchange, so that the heat recovery efficiency of the flue gas is effectively improved.

[0013] As a further improvement of the above technical solution, the heat exchange pipes are arranged on both sides of the denitration device along the length direction of the heating cavity in the preheating box. The flue gas flows in the preheating box and passes through a heat exchange pipe before entering the denitration device, so that the heat in the flue gas can be recovered once, and the flue gas can be better controlled to reach a suitable temperature range when entering the denitration device. The flue gas after the denitration device passes through the heat exchange pipe again for heat exchange, so that the heat recovery efficiency of the flue gas is effectively improved.

[0014] As a further improvement of the above technical solution, the heat exchange pipes are arranged on both sides of the denitration device along the length direction of the heating cavity in the preheating box. The flue gas flows in the preheating box and passes through a heat exchange pipe before entering the denitration device, so that the heat in the flue gas can be recovered once, and the flue gas can be better controlled to reach a suitable temperature range when entering the denitration device. The flue gas after the denitration device passes through the heat exchange pipe again for heat exchange, so that the heat recovery efficiency of the flue gas is effectively improved.

[0015] A combustion method, using the above-mentioned ammonia fuel porous medium combustion system, the mixed gas of fuel gas and combustion-supporting gas is introduced into the porous medium burner from the premixed gas uniform distribution chamber, and the combustion-supporting gas is sprayed from the combustion-supporting gas spray pipe on the gas outlet side of the porous medium burner.

[0016] The technical scheme has at least the following beneficial effects: the fuel gas can be input from the outside, the combustion-supporting gas can be input from the combustion-supporting fan, the mixed gas after mixing is output from the premixed gas uniform distribution chamber to the porous medium burner, the first-stage combustion is performed in the plurality of combustion holes of the porous medium burner, the porous medium burner makes the flammable range wider, the combustion efficiency is improved, the flame temperature is more uniform, the local high-temperature area is reduced, the pollutant emission is reduced, the first-stage combustion can be maintained under the fuel-rich condition, the production of the lower nitrogen oxide in the combustion area is ensured, the combusted gas is discharged into the heating cavity, the workpiece on the gas outlet side is heated, the combustion-supporting gas is input from the start end of the combustion-supporting gas injection pipe to the gas outlet side of the porous medium burner along the bending of the end of the combustion-supporting gas injection pipe through the pipeline of the air outlet end of the combustion-supporting fan, the combusted gas is supplemented with combustion-supporting air, the flammable gas in the mixed gas is further combusted on the gas outlet side of the porous medium burner, the second-stage combustion is realized, the unburned ammonia gas in the first-stage combustion is consumed under the lower equivalence ratio, the nitrogen oxide emission can be effectively controlled when the ammonia gas is used as the combustion heating, the combustion efficiency of the ammonia gas is greatly improved through the second-stage combustion, the flammable range of the ammonia gas is wider, and therefore the heating production efficiency of the workpiece is improved and the production energy consumption is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiment description will be briefly described. Obviously, the described drawings are only a part of the embodiments of the present application, and other design schemes and drawings can be obtained by those skilled in the art without creative labor on the basis of the drawings.

[0018] Figure 1 It is a structure schematic diagram of the ammonia fuel porous medium combustion system of the present application.

[0019] Figure 2 It is a perspective view of the combustion assembly of the present application.

[0020] Figure 3 It is a perspective view of the heat exchanger of the present application, in which one side wall of the heat exchanger is hidden to show the internal structure.

[0021] In the drawings: 100-heating furnace, 200-combustion assembly, 210-porous medium burner, 220-premixed gas uniform distribution chamber, 230-combustion-supporting gas injection pipe, 240-second-stage combustion-supporting air distribution box, 300-mixed gas box, 400-combustion-supporting fan, 500-circulating fan, 600-preheating box, 610-preheating pipe, 700-heat exchange pipe, 800-denitration device, 900-heat exchanger, 910-flue gas inlet, 920-flue gas outlet, 930-liquid ammonia inlet, 940-ammonia gas outlet, 950-drain pipe. DETAILED DESCRIPTION

[0022] Embodiments of the present application are described below in detail with reference to the accompanying drawings, wherein the same or similar components are denoted by the same or similar reference numerals throughout the drawings. The embodiments described below are exemplary and are for the purpose of explanation only, and are not to be understood as limiting the present application.

[0023] In the description of the present application, it should be understood that the orientation description, such as the orientation or position relationship indicated by up, down, front, back, left, right, etc. is based on the orientation or position relationship shown in the drawings, and is only for the purpose of facilitating the description of the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation of the present application.

[0024] In the description of the present application, several meanings are one or more, and the meaning of multiple is two or more, greater than, less than, more than, etc. are understood as not including the number, above, below, etc. are understood as including the number. If the first, second is described, it is only for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated or the order of technical features indicated.

[0025] In the description of the present application, unless otherwise explicitly limited, the words such as setting, installing, connecting, etc. should be broadly understood, and those skilled in the art can reasonably determine the specific meaning of the above words in the present application in combination with the specific content of the technical solution.

[0026] Referring to Figure 1 With Figure 2The application discloses an ammonia fuel porous medium combustion system, which comprises a heating furnace 100, a combustion assembly 200, a gas mixing box 300 and a combustion air fan 400, wherein the heating furnace 100 is internally provided with a heating cavity; the combustion assembly 200 comprises a porous medium burner 210, a premixed gas uniform distribution chamber 220 and a combustion gas nozzle 230; the porous medium burner 210 is located in the heating cavity; the porous medium burner 210 is a double-layer porous medium wrapped by a metal shell; the burner with the added porous medium tends to be uniform in the combustion area temperature and maintains a relatively stable temperature gradient due to the existence of three heat exchange modes of convection, heat conduction and radiation; the gas outlet side of the porous medium burner 210 is directed to the inside of the heating cavity; the premixed gas uniform distribution chamber 220 is connected to the gas inlet side of the porous medium burner 210; the premixed gas uniform distribution chamber 220 is communicated with a plurality of combustion holes; the combustion gas nozzle 230 is located beside the porous medium burner 210; the tail end of the combustion gas nozzle 230 extends to the gas outlet side of the porous medium burner 210 and is bent towards the gas outlet direction close to the porous medium burner 210; the gas mixing box 300 is provided with a gas inlet, a primary combustion gas inlet and a premixed gas outlet; the premixed gas outlet and the premixed gas uniform distribution chamber 220 are communicated with each other; the air outlet end of the combustion air fan 400 is communicated with the primary combustion gas inlet and the initial end of the combustion gas nozzle 230 through pipelines.

[0027] From the above, the workpiece that needs to be heated for production can be sent into the heating cavity, and the workpiece is heated by the combustion assembly 200 when passing through the combustion assembly 200. Specifically, ammonia gas is input from the gas inlet into the gas mixing box 300, and the combustion air fan 400 outputs combustion gas from the outlet end through the pipeline to the gas mixing box 300 from the first combustion gas inlet, and the ammonia gas and the combustion gas are mixed in the gas mixing box 300, and then the mixed gas is output from the premixed gas outlet to the porous medium burner 210 for first-stage combustion in the plurality of combustion holes of the porous medium burner 210. The porous medium burner 210 widens the flammable range, improves the combustion efficiency, and also makes the flame temperature more uniform, reduces the local high-temperature area, and reduces the pollutant emission. The first-stage combustion can be maintained under fuel-rich conditions to ensure that the nitrogen oxide is generated in the combustion zone. The gas after combustion is discharged into the heating cavity to heat the workpiece on the gas outlet side. At the same time, the combustion air fan 400 outputs combustion gas from the combustion gas nozzle 230 through the pipeline, and blows along the bending of the combustion gas nozzle 230 to the gas outlet side of the porous medium burner 210, and supplements the combustion air in the mixed gas to further combust the combustible gas on the gas outlet side of the porous medium burner 210, realizes the second-stage combustion, and consumes the unburned ammonia gas at a lower equivalence ratio. Thus, when ammonia gas is used for combustion heating, the nitrogen oxide emission can be effectively controlled, the combustion efficiency of the ammonia gas is greatly improved through the second-stage combustion, the flammable range of the ammonia gas is widened, the heating production efficiency of the workpiece is improved, the production energy consumption is reduced, the stable and uniform combustion of the ammonia gas is ensured, and the production stability and efficiency of the ammonia fuel system for heating the workpiece are improved.

[0028] In actual application, the porous medium burner 210 is provided with a plurality of porous medium burners along the length direction of the heat exchange cavity, and the gas mixing box 300 is also provided with a plurality of gas mixing boxes along the length direction of the heat exchange cavity. One gas mixing box 300 can input the mixed gas of the combustion gas and the combustion gas to one porous medium burner 210, or one gas mixing box 300 can input the mixed gas of the combustion gas and the combustion gas to a plurality of porous medium burners 210. Similarly, a plurality of combustion air boxes can be provided along the length direction of the heat exchange cavity, and the combustion air is sent into the combustion air box and then supplied to the combustion gas nozzles 230 of the plurality of porous medium burners 210.

[0029] In order to improve the area of combustion-supporting gas flowing on the gas outlet side of the porous medium burner 210, the number of combustion-supporting gas nozzles 230 can be multiple. Specifically, a secondary combustion-supporting air distribution box 240 is arranged on the outer side of the premixed gas uniform distribution chamber 220, and the secondary combustion-supporting air distribution box 240 extends around the porous medium burner 210. A plurality of combustion-supporting gas nozzles 230 are connected to one side of the secondary combustion-supporting air distribution box 240 around the porous medium burner 210, and the plurality of combustion-supporting gas nozzles 230 can rotate and be positioned along an axis parallel to the gas outlet direction of the porous medium burner 210. In actual application, the combustion-supporting gas nozzles 230 can be frictionally connected to the secondary combustion-supporting air distribution box 240, and a rubber tube can be used to seal between the secondary combustion-supporting air distribution box 240 and the combustion-supporting gas nozzles 230. The air outlet end of the combustion-supporting air blower 400 is connected to the secondary combustion-supporting air distribution box 240 through a pipeline. The combustion-supporting gas enters the secondary combustion-supporting air distribution box 240 and is distributed to the plurality of combustion-supporting gas nozzles 230. Thus, the plurality of combustion-supporting gas nozzles 230 blow the secondary combustion-supporting air on the gas outlet side of the porous medium burner 210, strengthen the mixing of the secondary combustion-supporting air and the primary combustion tail gas, make the unburned ammonia gas quickly and fully contact with the secondary combustion-supporting air to generate a combustion reaction, and make the secondary combustion-supporting air more uniformly distributed, so as to better supplement the combustion-supporting air for the gas after combustion and further improve the combustion efficiency. In actual application, four combustion-supporting gas nozzles 230 can be arranged to blow the secondary combustion-supporting air in a four-corner tangential circle form along the vertical flame direction. In addition, the combustion-supporting gas nozzles 230 can slide to adjust the position along the gas outlet direction of the porous medium burner 210, and the rotation adjustment of the outlet angle can further improve the combustion efficiency. In addition, the premixed gas uniform distribution chamber 220, the secondary combustion-supporting air distribution box 240, and the plurality of combustion-supporting gas nozzles 230 form an integral whole, which can be translated and adjusted in the heating cavity before use to adjust the distance from the gas outlet side of the porous medium burner 210, so as to better supplement the combustion-supporting air for the gas after combustion and further improve the combustion efficiency.

[0030] In order to better input the mixed gas into the plurality of combustion holes of the porous medium burner 210, in the present embodiment, the space in the premixed gas uniform distribution chamber 220 gradually increases towards the direction close to the porous medium burner 210. After the mixed gas is input from the end of the premixed gas uniform distribution chamber 220 with a smaller internal space, the mixed gas gradually diffuses towards the porous medium burner 210 due to the gradually increasing internal space of the premixed gas uniform distribution chamber 220 towards the direction close to the porous medium burner 210, and the speed of the mixed gas entering the porous medium burner 210 is reduced, so that the mixed gas more uniformly enters the plurality of combustion holes, and the uniformity of the temperature distribution of the porous medium burner 210 is improved.

[0031] The application also comprises a circulating fan 500 and a preheating box 600, the preheating box 600 is located in the heating cavity away from the combustion assembly 200, a plurality of preheating pipes 610 are connected on the preheating box 600 along the length direction of the heating cavity, the plurality of preheating pipes 610 are communicated with the preheating box 600 respectively, a plurality of preheating holes are arranged on the plurality of preheating pipes 610 respectively, since the workpiece passes above the preheating pipes 610, the preheating holes can be arranged on the air inlet side of the preheating pipes 610, the air outlet end of the circulating fan 500 is connected to the side of the preheating box 600 away from the combustion assembly 200 through a pipeline, and the air inlet end of the circulating fan 500 is connected to the heating cavity. The air inlet end of the circulating fan 500 draws flue gas from the heating cavity and blows the flue gas into the preheating box 600 through the pipeline, the flue gas can be distributed to the plurality of preheating pipes 610 connected to the preheating box 600 after entering the preheating box 600, and then reflows into the space of the heating cavity away from the combustion assembly 200 from the preheating holes on the preheating pipes 610, the workpiece can enter from the side of the heating cavity provided with the preheating box 600, and the workpiece is preheated by the flue gas, so that the heat utilization rate of the flue gas is improved, the heating speed of the workpiece is improved, and the production energy consumption is further reduced.

[0032] In order to better recover the heat of the flue gas, in the embodiment, a heat exchange pipe 700 is arranged in the preheating box 600, one end of the heat exchange pipe 700 is connected to the air outlet end of the combustion-supporting fan 400 through a pipeline, and the other end of the heat exchange pipe 700 is connected to the primary combustion-supporting gas air inlet through a pipeline. The air outlet end of the combustion-supporting fan 400 inputs combustion-supporting gas to the heat exchange pipe 700 through a pipeline, and the flue gas exchanges heat with the heat exchange pipe 700 when flowing in the preheating box 600, so that the combustion-supporting gas is preheated and heated by the flue gas first, and then enters the mixing box for mixing, the initial temperature of the mixed gas is improved, which is beneficial to improve the ammonia gas combustion temperature and more fully recover and utilize the heat of the flue gas.

[0033] In order to better control the emission pollution of the flue gas, in the embodiment, a denitration device 800 is arranged in the preheating box 600, in actual application, the denitration device 800 can be used, and the main function of the denitration device 800 is to convert nitrogen oxides in the flue gas into harmless nitrogen and water vapor through selective catalytic reduction technology, so as to reduce the pollution to the environment. When the flue gas flows in the preheating box 600, the flue gas passes through the denitration device 800, and the nitrogen oxides in the flue gas and the residual ammonia in the flue gas and the supplementary sprayed ammonia react under the action of the medium-temperature catalyst, the nitrogen oxides are reduced to nitrogen, so that the pollution generated by the combustion exhaust gas can be effectively reduced.

[0034] To better reduce the temperature of the flue gas exiting the preheating box 600, in this embodiment, heat exchange tubes 700 are respectively arranged on both sides of the heating chamber of the denitrification device 800 inside the preheating box 600. Before entering the denitrification device, the flue gas flows through a heat exchange tube 700 within the preheating box 600, allowing for initial heat recovery and better control of the flue gas reaching a suitable temperature range upon entering the denitrification device 800. After passing through the denitrification device 800, the flue gas again passes through the heat exchange tube 700 for heat exchange, thus effectively improving the heat recovery efficiency of the flue gas.

[0035] The present invention also includes a heat exchanger 900, such as Figure 3 As shown, the heat exchanger 900 is provided with interconnected flue gas inlet 910 and flue gas outlet 920, and interconnected liquid ammonia inlet 930 and ammonia outlet 940. A flue gas exhaust pipe is connected to the side of the preheating box 600 near the combustion assembly 200, and the exhaust pipe is connected to the flue gas inlet 910. The heat exchanger 900 has two separate heat exchange chambers. Liquid ammonia required for combustion is input into one heat exchange chamber of the heat exchanger 900 through the liquid ammonia inlet 930. The flue gas, after heat exchange and denitrification in the preheating box 600, is then input into the other heat exchange chamber of the heat exchanger 900 through the flue gas inlet 910. The liquid ammonia absorbs heat from the flue gas and turns into ammonia gas, thus further cooling the discharged flue gas, reducing the energy consumption required for liquid ammonia vaporization, reducing overall system heat loss, and improving overall thermal efficiency.

[0036] The heat exchanger 900 comprises a heat exchange shell, an air inlet joint and a first baffle are arranged on the air inlet side of the heat exchange shell along the left-right direction, the first baffle and the air inlet side of the heat exchange shell form a first baffle cavity, a second baffle and an air outlet joint are arranged on the bottom side of the heat exchange shell along the left-right direction, the flue gas inlet 910 is formed on the air inlet joint, the flue gas outlet 920 is formed on the air outlet joint, the second baffle and the bottom side of the heat exchange shell form a second baffle cavity, three groups of flue gas discharge groups are arranged in the heat exchange shell along the left-right direction, each group of flue gas discharge groups comprises a plurality of flue gas discharge pipes, each flue gas discharge pipe extends along the up-down direction, the plurality of flue gas discharge pipes form a heat exchange cavity, and another heat exchange cavity is formed outside the plurality of flue gas discharge pipes in the heat exchange shell, the top end of the flue gas discharge pipe in the left flue gas discharge group is communicated with the air inlet joint, the bottom end of the flue gas discharge pipe in the middle flue gas discharge group is communicated with the first baffle cavity, the top end of the flue gas discharge pipe in the right flue gas discharge group is communicated with the second baffle cavity, and the bottom end of the flue gas discharge pipe in the right flue gas discharge group is communicated with the air outlet joint, so that an up-down zigzag heat exchange cavity is formed in the heat exchange shell for flue gas flow and heat exchange, flue gas enters the flue gas discharge pipe on the left from the air inlet joint, is folded to the rear by the first baffle, enters the flue gas discharge pipe in the middle, is folded to the rear by the second baffle, and is discharged from the air outlet joint. A liquid inlet groove is arranged on the left side of the heat exchange shell, the liquid inlet groove and the inside of the heat exchange shell are communicated with each other, an air outlet groove is arranged on the right side of the heat exchange shell, the air outlet groove and the inside of the heat exchange shell are communicated with each other, the liquid ammonia inlet 930 is formed on the liquid inlet groove, and the ammonia gas outlet 940 is formed on the air outlet groove, so that a heat exchange cavity is formed in the heat exchange shell along the left-right direction, and part of the ammonia gas after gasification and part of the liquid ammonia not gasified are discharged from the air outlet groove after the liquid ammonia enters the heat exchange shell from the liquid inlet groove.

[0037] As a further improvement of the above technical solution, the heat exchanger 900 is provided with a drain pipe 950, which is communicated with the flue gas inlet 910 and the flue gas outlet 920. Condensed water is generated on the inner wall of the drain pipe 950 during heat exchange of flue gas, which dissolves and captures residual ammonia, a small amount of dust and a small amount of nitrogen oxides in the flue gas, thereby achieving further control of pollutants. The condensed water can be discharged and collected from the drain pipe 950 for recycling. The collected condensed water can be used as make-up water in the film boiling, spraying and cleaning processes in the aluminum processing technology. In addition, the volume contraction caused by the condensation of water vapor in the condenser generates a negative pressure, which can partially offset the pressure loss caused by the multi-stage heat exchanger 900 and the denitration device 800.

[0038] A combustion method, the above-mentioned ammonia fuel porous medium combustion system is applied, the mixed gas of fuel gas and combustion-supporting gas is introduced into the porous medium combustor 210 from the premixed gas uniform distribution chamber 220, and the combustion-supporting gas is sprayed from the combustion-supporting gas nozzle 230 to the air outlet side of the porous medium combustor 210.

[0039] The gas can be input from the outside, and the combustion-supporting gas can be input from the combustion-supporting fan 400. The mixed gas is output from the premixed gas uniform distribution chamber 220 to the porous medium burner 210, and the first-stage combustion is performed in the plurality of combustion holes of the porous medium burner 210. The porous medium burner 210 widens the flammable range, improves the combustion efficiency, makes the flame temperature more uniform, reduces the local high-temperature area, and reduces the pollutant emission. The first-stage combustion can be maintained in the fuel-rich condition to ensure that the nitrogen oxide is generated in the combustion area. The burned gas is discharged into the heating cavity to heat the workpiece on the gas outlet side. Meanwhile, the combustion-supporting fan 400 discharges the combustion-supporting gas from the combustion-supporting gas injection pipe 230 through the pipeline, blows the combustion-supporting gas to the gas outlet side of the porous medium burner 210 along the bending of the combustion-supporting gas injection pipe 230, and supplements the combustion-supporting air in the burned gas to further burn the flammable gas on the gas outlet side of the porous medium burner 210, so that the second-stage combustion is realized. The unburned ammonia gas in the first-stage combustion is consumed at a lower equivalence ratio, so that the nitrogen oxide emission can be effectively controlled when the ammonia gas is used for combustion heating, and the combustion efficiency of the ammonia gas is greatly improved through the second-stage combustion. The flammable range of the ammonia gas is widened, so that the heating production efficiency of the workpiece is improved, and the production energy consumption is reduced.

[0040] The preferred embodiments of the present application are specifically described above, but the present application is not limited to the embodiments. Those skilled in the art can make various equivalent modifications or replacements without departing from the spirit of the present application. The equivalent modifications or replacements are included in the scope defined by the claims of the present application.

Claims

1. An ammonia-fuelled porous media combustion system, characterized by: include: A heating furnace (100) has a heating chamber inside; Combustion assembly (200) includes a porous media burner (210), a premixed gas distribution chamber (220), and a combustion-supporting nozzle (230). The porous media burner (210) is located inside the heating chamber, with the outlet side of the porous media burner (210) facing the interior of the heating chamber. The premixed gas distribution chamber (220) is connected to the inlet side of the porous media burner (210) and is connected to multiple combustion holes. The combustion-supporting nozzle (230) is located beside the porous media burner (210), with its end extending to the outlet side of the porous media burner (210) and bending toward the outlet direction of the porous media burner (210). The mixing chamber (300) is provided with a gas inlet, a primary auxiliary gas inlet and a premixed gas outlet, wherein the premixed gas outlet is connected to the premixed gas distribution chamber (220); The combustion-supporting blower (400) has its outlet end connected to the first-stage combustion-supporting gas inlet and the beginning of the combustion-supporting gas nozzle (230) respectively through pipelines; The premixed gas distribution chamber (220) is provided with a secondary combustion air distribution box (240) on the outside. The secondary combustion air distribution box (240) extends around the porous medium burner (210). One side of the secondary combustion air distribution box (240) is connected to a plurality of combustion air nozzles (230) around the porous medium burner (210). The plurality of combustion air nozzles (230) can rotate and be positioned along an axis parallel to the gas outlet direction of the porous medium burner (210). The outlet end of the combustion air blower (400) is connected to the secondary combustion air distribution box (240) through a pipeline.

2. The ammonia fuel porous media combustion system of claim 1, wherein: The space within the premixed gas distribution chamber (220) gradually increases towards the porous media burner (210).

3. The ammonia fuel porous media combustion system of claim 1, wherein: It also includes a circulating fan (500) and a preheating box (600). The preheating box (600) is located in the heating chamber on the side away from the combustion assembly (200). Multiple preheating pipes (610) are connected to the preheating box (600) along the length of the heating chamber. Multiple preheating holes are provided on the multiple preheating pipes (610). The air outlet of the circulating fan (500) is connected to the side of the preheating box (600) away from the combustion assembly (200) through a pipeline. The air inlet of the circulating fan (500) is connected to the heating chamber.

4. The ammonia fuel porous media combustion system of claim 3, wherein: The preheating box (600) is equipped with a heat exchange tube (700). One end of the heat exchange tube (700) is connected to the air outlet of the combustion fan (400) through a pipeline, and the other end of the heat exchange tube (700) is connected to the primary combustion gas inlet through a pipeline.

5. The ammonia fuel porous media combustion system of claim 4, wherein: The preheating box (600) is equipped with a denitrification device (800).

6. An ammonia fuel porous media combustion system according to claim 5, wherein: The heat exchange tubes (700) are respectively arranged on both sides of the denitrification device (800) along the length of the heating chamber inside the preheating box (600).

7. The ammonia fuel porous media combustion system of claim 3, wherein: The heat exchanger (900) is further provided with a flue gas inlet (910) and a flue gas outlet (920) which are in communication with each other, and an ammonia liquid inlet (930) and an ammonia gas outlet (940) which are in communication with each other; the preheating box (600) is connected with a flue gas discharge pipe on one side close to the combustion assembly (200), and the flue gas discharge pipe is connected with the flue gas inlet (910).

8. The ammonia fuel porous media combustion system of claim 7, wherein: The heat exchanger (900) is further provided with a drain pipe (950) which is in communication with the flue gas inlet (910) and the flue gas outlet (920).

9. A combustion method using the ammonia fuel porous medium combustion system according to any one of claims 1 to 8, characterized by: The mixed gas of the fuel gas and the combustion-supporting gas is introduced into the porous medium burner (210) from the premixed gas uniform distribution chamber (220), and the combustion-supporting gas is sprayed from the combustion-supporting gas spray pipe (230) on the gas outlet side of the porous medium burner (210).

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