Pre-combustion furnace system for coupling alternative fuel oxygen-enriched combustion with bypass ventilation

Abstract

The invention belongs to the technical field of industrial kilns, and discloses an alternative fuel oxygen-enriched combustion coupled bypass ventilation pre-combustion furnace system which comprises a bypass ventilation system, a pre-combustion furnace, a decomposing furnace and a preheater, the lower end of the decomposing furnace is connected to a kiln tail smoke chamber, the pre-combustion furnace is a stepped furnace, and the bypass ventilation system is connected with the pre-combustion furnace. The feeding end of the stepped furnace is connected with an alternative fuel input pipe and a tertiary air pipe, the bypass ventilation system comprises a circulation pipeline, a cyclone separator and a heat pipe heat exchange device, the kiln tail smoke chamber is connected with the circulation pipeline, the circulation pipeline is connected to the cyclone separator, and the heat pipe heat exchange device is connected to the heat pipe heat exchange device. A solid outlet of the cyclone separator is connected to the decomposing furnace, a gas outlet of the cyclone separator is connected to a heat pipe heat exchange device through a high-temperature flue gas pipeline, and the high-temperature flue gas pipeline is connected to an exhaust fan through a bag dust collection device; the feeding end of the pre-combustion furnace is further connected with an air pipeline, and the air pipeline is connected to an air blower through the heat pipe heat exchange device. Cyclic enrichment of chlorine elements in the cement kiln can be broken through, and the content of the chlorine elements is reduced; and meanwhile, the temperature of air after heat exchange can be increased, and energy consumption is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of industrial kilns, and in particular relates to a pre-combustion furnace system with alternative fuel oxygen-enriched combustion coupled with bypass ventilation. Background Art

[0002] Under the background of "carbon peak and carbon neutrality", the large-scale use of energy-containing solid wastes such as garbage-derived materials, tire-derived materials, and biomass as alternative fuels has become the most concerned carbon emission reduction technology in the cement industry. At present, the cement industry still mostly adopts the method of directly injecting alternative fuels into the decomposition furnace when using alternative fuels. On the one hand, the alternative fuels have high moisture content, low calorific value, large particle size, slow combustion speed, and large oxygen demand, which leads to unstable thermal system of cement kilns; on the other hand, the chlorine element in the alternative fuel is relatively high, which circulates and enriches inside the cement kiln, breeds a large amount of crusting, and the kiln has poor ventilation capacity, which may even cause blockage. At the same time, many unfavorable factors such as unstable feeding and serious air leakage have jointly restricted the promotion and use of alternative fuels. Although the bypass ventilation technology commonly used in the cement industry can effectively break the cyclic enrichment of chlorine elements inside the cement kiln, the high-temperature flue gas discharged from the smoke chamber wastes a lot of heat energy, which runs counter to the energy conservation and carbon reduction direction of the cement industry. Therefore, how to inhibit the cyclic enrichment of chlorine elements inside the cement kiln while improving the combustion efficiency of alternative fuels and reducing energy consumption has become an important technical problem that needs to be solved in this field. Summary of the invention

[0003] The purpose of the present invention is to provide a pre-combustion furnace system with alternative fuel oxygen-enriched combustion coupled with bypass ventilation, which is used to solve the technical problem in the prior art that it is difficult to effectively reduce energy consumption while suppressing the circulation and enrichment of chlorine elements inside a cement kiln.

[0004] The precombustion furnace system with alternative fuel oxygen-enriched combustion coupled with bypass ventilation comprises a bypass ventilation system, a precombustion furnace, a decomposition furnace and a preheater. The lower end of the decomposition furnace is connected to the kiln tail smoke chamber. The precombustion furnace is a step furnace. The feeding end of the step furnace is connected to an alternative fuel input pipe and a tertiary air duct. The bypass ventilation system comprises a circulation pipeline, a cyclone separator and a heat pipe heat exchange device. The kiln tail smoke chamber is connected to a circulation pipeline, and the circulation pipeline is connected to a cyclone separator. The solid outlet of the cyclone separator is connected to the decomposition furnace and the gas outlet is connected to the heat pipe heat exchange device through a high-temperature flue gas pipeline. The high-temperature flue gas pipeline is then connected to an exhaust fan through a bag dust collection device. The feeding end of the precombustion furnace is also connected to an air pipeline, and the air pipeline is connected to a blower through the heat pipe heat exchange device.

[0005] Preferably, the tertiary air duct is connected to an oxygen-enriched gas main pipe that outputs oxygen-enriched gas from the oxygen-enriching device, and a plurality of oxygen-enriched gas nozzles are also provided in the middle portion of the precombustion furnace for spraying oxygen-enriched gas to the reaction zones at corresponding positions. The air cannons provided at each step in the precombustion furnace are filled with oxygen-enriched gas, and each air cannon and each oxygen-enriched gas nozzle are connected to the oxygen-enriching device that outputs oxygen-enriched gas through a pipeline for receiving oxygen-enriched gas.

[0006] Preferably, the area in the middle of the precombustion furnace where an oxygen-rich gas nozzle is provided is a high-temperature zone, and the oxygen-rich gas nozzle in the high-temperature zone includes two side nozzles and an oblique upper nozzle, the two side nozzles are provided on the side walls inside the precombustion furnace and face the material in the high-temperature zone, and the oblique upper nozzle is provided on the inclined top wall at the top of the high-temperature zone, and the oblique upper nozzle is inclined toward the material in the high-temperature zone.

[0007] Preferably, a second oxygen-enriched gas nozzle is provided at the first constriction, and the spraying direction of the second oxygen-enriched gas nozzle is toward the center of the first constriction.

[0008] Preferably, in the heat pipe heat exchange device, high-temperature flue gas is introduced into one side of the lower ventilation part located at the lower part of the heat pipe, and cold air delivered by a blower is introduced into the other side of the upper ventilation part located at the upper part of the heat pipe, and a high-boiling-point organic solvent is used inside each heat pipe.

[0009] Preferably, the bypass ventilation system also includes a zipper machine, an ash storage bin and a kiln tail chimney, the heat pipes of the heat pipe heat exchange device are vertically arranged, the high-temperature flue gas duct is connected to the lower ventilation part, the bottom end of the lower ventilation part is provided with a dust outlet, and the connection port between the high-temperature flue gas duct and the lower ventilation part is higher than the dust outlet; the dust outlet and the smoke outlet of the bag dust collecting device both lead to the zipper machine, and the output end of the zipper machine is arranged at the entrance of the ash storage bin.

[0010] Preferably, the inlet pressure of the oxygen-enriched gas nozzle 1 is 20-40 kPa; wherein the spray angle of the oblique upper nozzle is designed to be inclined at 45°-60° relative to the vertical direction.

[0011] Preferably, the bypass ventilation design ratio of the bypass ventilation system is 3%-10%, and the exhaust fan power can be selected to be 60-200kW.

[0012] The advantages of the present invention are as follows: the bypass venting system of the present invention uses an exhaust fan to extract part of the smoke in the smoke chamber from the system, and after removing most of the dust through a cyclone separator, it exchanges heat with air in a heat pipe and enters a bag dust collector, and after further removing the smoke dust, it is discharged from the system, which can break the cycle enrichment of chlorine elements inside the cement kiln and reduce the chlorine content. At the same time, the bypass venting system uses heat pipe heat exchange to utilize the waste heat of the bypass venting smoke, which can increase the temperature of the air after heat exchange and reduce energy consumption.

[0013] The present invention also uses oxygen-rich gas to increase the oxygen content of the tertiary air entering the feed end. Since the oxygen consumption of alternative fuels is greater than that of pulverized coal, a large proportion of alternative fuels used to replace pulverized coal will lead to oxygen deficiency in the decomposition furnace, and additional oxygen supply is required to ensure that the fuel is fully burned and releases heat. This solution can solve the problem of insufficient oxygen supply in the pre-combustion furnace by increasing the oxygen content of the tertiary air.

[0014] During the operation, each time the air cannon is started, the fuel is transferred to the next step while oxygen is supplemented, which avoids the problem of insufficient oxygen content in other parts of the pre-combustion furnace except the inlet end to a certain extent. In the middle part of the pre-combustion furnace, since most of the alternative fuels are burned in the previous stage, the oxygen content has dropped significantly, and the proportion of combustibles in the alternative fuels has decreased, so further oxygen supplementation is required. This solution can effectively supplement oxygen at the corresponding position through the additional oxygen-enriched gas nozzle 1, improve the combustion efficiency of the alternative fuel at this position, and further improve the combustion efficiency of the alternative fuel at each position in the pre-combustion furnace, reducing the heat loss caused by incomplete combustion inside the decomposition furnace. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 The present invention is a schematic structural diagram of a pre-combustion furnace system with alternative fuel oxygen-enriched combustion coupled with bypass ventilation.

[0016] Figure 2 yes Figure 1 Schematic diagram of the structure of the pre-combustion furnace in the structure shown.

[0017] Figure 3 yes Figure 2 Schematic diagram of the structure of the nozzles on both sides of the structure shown.

[0018] Figure 4 yes Figure 1 Structural schematic diagram of the bypass ventilation system in the structure shown.

[0019] Figure 5 yes Figure 1 Schematic diagram of the structure of the pre-combustion furnace and the decomposition furnace in the structure shown.

[0020] Figure 6 yes Figure 1 CFD simulation results of the carbon monoxide content in the calciner for the configuration shown.

[0021] The marks in the accompanying drawings include: 1. decomposition furnace, 101. oxygen-enriched gas nozzle 2, 2. preheater, 3. oxygen-enriching device, 4. precombustion furnace, 401. feeding end, 402. air cannon, 403. nozzles on both sides, 404. nozzles on the upper side, 405. tertiary air duct, 406. air duct, 407. raw material discharge pipe, 408. alternative fuel input pipe, 5. kiln tail smoke chamber, 6. bypass ventilation system, 601. blower, 602. upper ventilation part, 603. lower ventilation part, 604. heat pipe, 605. zipper machine, 606. bag dust collection device, 607. exhaust fan, 608. ash storage bin, 609. cyclone separator. DETAILED DESCRIPTION

[0022] The specific implementation modes of the present invention are further explained in detail below by describing the embodiments with reference to the accompanying drawings, so as to help those skilled in the art to have a more complete, accurate and in-depth understanding of the inventive concept and technical solution of the present invention.

[0023] like Figures 1 to 6 As shown, the present invention provides a precombustion furnace system with alternative fuel oxygen-enriched combustion coupled with bypass ventilation, comprising a precombustion furnace 4, a decomposition furnace 1 and a preheater 2, the lower end of the decomposition furnace 1 is connected to the kiln tail smoke chamber 5, the precombustion furnace 4 is a step furnace, the feed end 401 of the step furnace is connected to an alternative fuel input pipe 408 and a tertiary air duct 405, the tertiary air duct 405 is connected to an oxygen-enriched gas main pipe for outputting oxygen-enriched gas from an oxygen-enriching device 3, a plurality of oxygen-enriched gas nozzles are further provided in the middle portion of the precombustion furnace 4 for spraying oxygen-enriched gas to the reaction zones at corresponding positions, oxygen-enriched gas is filled into air cannons 402 arranged at each step in the precombustion furnace 4, and each air cannon 402 and each oxygen-enriched gas nozzle are connected to the oxygen-enriching device 3 for outputting oxygen-enriched gas through a pipeline for receiving oxygen-enriched gas.

[0024] The kiln tail smoke chamber 5 is connected to a circulation pipeline, and the circulation pipeline is connected to the cyclone separator 609. The cyclone separator 609 is a gas-solid separation device. The flue gas enters the separator to form a high-speed rotating vortex. During the rotation process, the density of solid particles is greater than that of the gas, and the centrifugal force they are subjected to is also greater, and they will be thrown to the wall of the separator. The gas forms an upward spiral flow in the central area and continues to move upward, and the solid moves downward under the influence of gravity to achieve gas-solid separation. In this embodiment, the cyclone separator 609 is designed to have an inner diameter of about 2000 mm.

[0025] The solid outlet of the cyclone separator 609 is connected to the decomposition furnace 1, and the gas outlet is connected to the heat pipe heat exchange device through the high-temperature flue gas pipeline, and the high-temperature flue gas pipeline is connected to the exhaust fan 607 through the bag dust collection device 606; the feed end 401 of the pre-combustion furnace 4 is also connected to the air pipeline 406, and the air pipeline 406 is connected to the blower 601 through the heat pipe heat exchange device. The blower 601 inputs cold air into the air pipeline 406, and the cold air exchanges heat with the high-temperature flue gas in the high-temperature flue gas pipeline through the heat pipe heat exchange device. The air after heat exchange and the tertiary air melted into the oxygen-rich gas are input into the pre-combustion furnace 4 together to provide the oxygen required for combustion, so as to realize the additional oxygen supply required for the pre-combustion of the alternative fuel and ensure that the alternative fuel in the pre-combustion stage is fully burned.

[0026] The bypass venting system 6 formed by the above structure uses the exhaust fan 607 to extract part of the smoke in the smoke chamber from the system, and after the cyclone separator 609 removes most of the dust, it exchanges heat with the air in the heat pipe 604 and enters the bag dust collector 606, and then further removes the smoke and dust and discharges the system, which can break the chlorine element in the cement kiln. The cycle enrichment and reduce the chlorine content. At the same time, the bypass venting system 6 uses the heat exchange of the heat pipe 604 to utilize the waste heat of the bypass venting flue gas, which can increase the temperature of the air after heat exchange and reduce energy consumption. In this embodiment, the inlet temperature of the bag dust collector 606 is controlled to be lower than 180°C to avoid burning of the filter bag therein. The bypass venting design ratio of the bypass venting system 6 is 3%-10%, and the power of the exhaust fan 607 can be selected from 60-200kW.

[0027] The bag dust collecting device 606 is a dust collecting device. When the dust-containing gas passes through the filter bag, the gas can flow through, and the dust is adsorbed on the surface of the filter bag. Then, the dust is removed by pulse timing cleaning to complete the gas-solid separation. When the impeller of the exhaust fan 607 rotates, the blades push the gas to flow along the axial direction. The gas enters from the air inlet and is discharged from the air outlet in a direction parallel to the impeller axis under the push of the impeller.

[0028] The pre-combustion furnace 4 also includes a feed reamer and a raw material discharge pipe 407. The feed reamer is arranged at the front end of the first step in the pre-combustion furnace 4, and is used to uniformly transport the alternative fuel to the pre-combustion furnace 4; the raw material discharge pipe 407 is used to introduce the hot raw material in the C4 cyclone of the preheater 2 into the high temperature zone of the pre-combustion furnace 4, control the temperature of the pre-combustion furnace 4, and prevent the internal temperature of the pre-combustion furnace 4 from being too high and coking. The high temperature zone is located in the middle of the pre-combustion furnace 4, that is, the area where the oxygen-enriched gas nozzle 1 is arranged. Due to the supplementation of the pre-combustion effect generated by the oxygen-enriched gas and the combustion of the previous alternative fuel, the temperature of this part is very high, and the hot raw material entering the high temperature zone can absorb a certain amount of heat for reaction, avoiding excessive temperature.

[0029] The oxygen-enriched gas nozzle 1 in the high temperature zone includes two side nozzles 403 and an oblique upper nozzle 404. The two side nozzles 403 are arranged on the side walls inside the pre-combustion furnace 4 and face the material (alternative fuel) in the high temperature zone. The oblique upper nozzle 404 is arranged on the inclined top wall at the top of the high temperature zone, and the oblique upper nozzle 404 is inclined toward the material (alternative fuel) in the high temperature zone. The nozzle sprays oxygen-enriched gas toward the material in the reaction zone to enhance the airflow disturbance in the reaction zone.

[0030] In this embodiment, the pre-combustion furnace 4 is designed with a total of ten steps, and oxygen-enriched gas nozzles 1 are installed on the fourth, fifth and sixth steps. Six side nozzles 403 are installed on each side of each step, and three oblique upper nozzles 404 are installed correspondingly on the upper side, for a total of 9 oxygen-enriched gas nozzles 1. The inlet pressure of the oxygen-enriched gas nozzle 1 is 20-40kPa; the two side nozzles 403 spray horizontally, and the spray angle of the oblique upper nozzle 404 is designed to be inclined 45°-60° relative to the vertical direction. Two air cannons 402 are designed for each step, the pressure is set to 0.5MPa, the interval time of each air cannon 402 is set to 5s, and the cycle time is 100s.

[0031] The lower end outlet of the pre-combustion furnace 4 is connected to the upper part of the cone of the decomposition furnace 1. The first constriction is provided with an oxygen-enriched gas nozzle 2 101, and the injection direction of the oxygen-enriched gas nozzle 2 101 is toward the center of the first constriction. According to the CFD simulation results, the CO enrichment zone in the decomposition furnace 1 is located at the center of the first constriction of the decomposition furnace 1. Therefore, spraying oxygen-enriched gas into the center of the first constriction can enhance the air flow disturbance in the reaction zone, improve the combustion efficiency of the alternative fuel, and achieve the effect of increasing the amount of alternative fuel and reducing energy consumption.

[0032] The heat pipe heat exchange device is a highly efficient heat exchange device. High-temperature flue gas is introduced into one side of the lower ventilation part 603 located at the lower part of the heat pipe 604, and cold air delivered by the blower 601 is introduced into the other side of the upper ventilation part 602 located at the upper part of the heat pipe 604. A high-boiling-point organic solvent is used inside each heat pipe 604. The organic solvent absorbs heat from the high-temperature flue gas at the tail of the kiln and evaporates to the top of the heat pipe 604. After transferring heat to the cold air, it condenses into liquid and returns to the bottom of the heat pipe 604, forming a gravity-driven natural flow cycle. In this way, the heat exchange part of the heat pipe 604 can achieve rapid circulation heat exchange.

[0033] The bypass venting system 6 also includes a zipper machine 605, an ash storage bin 608 and a kiln tail chimney. The heat pipe 604 of the heat pipe heat exchange device is arranged vertically, the high-temperature flue gas duct is connected to the lower ventilation part 603, the bottom end of the lower ventilation part 603 is provided with a dust outlet, and the connection between the high-temperature flue gas duct and the lower ventilation part 603 is located higher than the dust outlet; the dust outlet and the smoke outlet of the bag dust collecting device 606 are both connected to the zipper machine 605, and the output end of the zipper machine 605 is arranged at the entrance of the ash storage bin 608. During operation, all the dust removed by the heat pipe 604 and the bag dust collecting device 606 enters the ash storage bin 608 for temporary storage through the zipper machine 605, and the smoke after the bag dust collecting is discharged through the exhaust fan 607 into the kiln tail chimney. The zipper machine 605 drives the solid particles input from each part to move forward together through the movement of the conveyor chain. The ash storage bin 608 temporarily stores the kiln ash collected by the bypass venting, which can be further processed later by fly ash water washing and other methods.

[0034] The working process of the present invention is as follows: the alternative fuel used in large proportion is input into the pre-combustion furnace 4 from the feed end 401, and is uniformly transported to the pre-combustion furnace 4 system through the feed reamer before the first step. At the same time, the oxygen-enriched gas prepared by the oxygen-enriching device 3 is transported to the front section of the air outlet of the tertiary air duct 405. The oxygen purity of the oxygen-enriched gas prepared by the oxygen-enriching oxygen-making device should be 80-99.9%, and when the mixed gas mixed with the tertiary air enters the pre-combustion furnace 4, the oxygen content of the mixed gas is in the range of 23-40%. The cold air input into the heat pipe heat exchange device by the blower 601 is also transported to the feed end 401 of the pre-combustion furnace 4 after heat exchange.

[0035] This scheme provides four oxygen supply methods during the working process, and one or more of them can be used to add oxygen to the decomposition furnace 1 and the precombustion furnace 4 system. 1. Combine high-concentration oxygen-rich air with tertiary air to generate low-concentration oxygen-rich air to enter the precombustion furnace 4. 2. Set oxygen-rich gas nozzles 1 on both sides and above the precombustion furnace 4 to spray oxygen-rich gas into the reaction zone to strengthen the airflow disturbance in the alternative fuel reaction zone. 3. Fill oxygen-rich air into the air cannon 402 of the precombustion furnace 4. When the air cannon 402 is started, oxygen-rich air is sprayed into the precombustion furnace 4. 4. Set oxygen-rich gas nozzle 2 101 at the first constriction of the decomposition furnace 1 to spray oxygen-rich gas into the center of the first constriction. Sufficient oxygen is provided to promote combustion, realize oxygen-rich combustion of alternative fuels, improve the combustion efficiency of alternative fuels, and reduce heat loss caused by incomplete combustion inside the decomposition furnace 1.

[0036] The present invention is described above by way of example in conjunction with the accompanying drawings. It is obvious that the specific implementation of the present invention is not limited to the above-mentioned method. As long as various non-substantial improvements are made using the inventive concept and technical solution of the present invention, or the inventive concept and technical solution are directly applied to other occasions without improvement, they are all within the protection scope of the present invention.

Claims

1. A pre-combustion furnace system with alternative fuel oxygen-enriched combustion coupled with bypass ventilation, comprising a bypass ventilation system (6), a pre-combustion furnace (4), a decomposition furnace (1) and a preheater (2), wherein the lower end of the decomposition furnace (1) is connected to a kiln tail smoke chamber (5), characterized in that: The pre-combustion furnace (4) is a stepped furnace, and the feed end (401) of the stepped furnace is connected to an alternative fuel input pipe (408) and a tertiary air duct (405). The bypass venting system (6) includes a circulation pipeline, a cyclone separator (609) and a heat pipe heat exchange device. The kiln tail smoke chamber (5) is connected to a circulation pipeline, and the circulation pipeline is connected to the cyclone separator (609). The solid outlet of the cyclone separator (609) is connected to the decomposition furnace (1) and the gas outlet is connected to the heat pipe heat exchange device through a high-temperature flue gas pipeline. The high-temperature flue gas pipeline is then connected to an exhaust fan (607) through a bag dust collection device (606); the feed end (401) of the pre-combustion furnace (4) is also connected to an air pipeline (406), and the air pipeline (406) is connected to a blower (601) through the heat pipe heat exchange device.

2. A pre-combustion furnace (4) system with alternative fuel oxygen-enriched combustion coupled with bypass ventilation according to claim 1, characterized in that: The tertiary air duct (405) is connected to an oxygen-enriched gas main pipe for outputting oxygen-enriched gas from the oxygen-enriching device (3). A plurality of oxygen-enriched gas nozzles are also provided in the middle of the pre-combustion furnace (4) for spraying oxygen-enriched gas to the reaction zones at corresponding positions. The air cannon (402) provided at each step in the pre-combustion furnace (4) is filled with oxygen-enriched gas. Each air cannon (402) and each oxygen-enriched gas nozzle are connected to the oxygen-enriching device (3) for outputting oxygen-enriched gas through a pipeline for receiving oxygen-enriched gas.

3. A pre-combustion furnace (4) system with alternative fuel oxygen-enriched combustion coupled with bypass ventilation according to claim 2, characterized in that: The area in the middle of the pre-combustion furnace (4) where an oxygen-enriched gas nozzle one is provided is a high-temperature zone. The oxygen-enriched gas nozzle one in the high-temperature zone comprises two side nozzles (403) and an oblique upper nozzle (404). The two side nozzles (403) are provided on the side walls inside the pre-combustion furnace (4) and face the material in the high-temperature zone. The oblique upper nozzle (404) is provided on the inclined top wall at the top of the high-temperature zone. The oblique upper nozzle (404) is inclined toward the material in the high-temperature zone.

4. A pre-combustion furnace (4) system with alternative fuel oxygen-enriched combustion coupled with bypass ventilation according to claim 2, characterized in that: An oxygen-rich gas nozzle 2 (101) is provided at the first constriction, and the spraying direction of the oxygen-rich gas nozzle 2 (101) is toward the center of the first constriction.

5. The pre-combustion furnace (4) system of alternative fuel oxygen-enriched combustion coupled with bypass ventilation according to claim 1, characterized in that: In the heat pipe heat exchange device, high-temperature flue gas is introduced into one side of a lower ventilation portion (603) located at the lower part of the heat pipe (604), and cold air delivered by a blower (601) is introduced into the other side of an upper ventilation portion (602) located at the upper part of the heat pipe (604). A high-boiling-point organic solvent is used inside each heat pipe (604).

6. A pre-combustion furnace (4) system with alternative fuel oxygen-enriched combustion coupled with bypass ventilation according to claim 5, characterized in that: The bypass ventilation system (6) also includes a zipper machine (605), an ash storage bin (608) and a kiln tail chimney. The heat pipe (604) of the heat pipe heat exchange device is vertically arranged, and the high-temperature flue gas duct is connected to the lower ventilation part (603). The bottom end of the lower ventilation part (603) is provided with a dust outlet. The connection port between the high-temperature flue gas duct and the lower ventilation part (603) is located higher than the dust outlet; the dust outlet and the dust outlet of the bag dust collecting device (606) both lead to the zipper machine (605), and the output end of the zipper machine (605) is arranged at the entrance of the ash storage bin (608).

7. A pre-combustion furnace (4) system with alternative fuel oxygen-enriched combustion coupled with bypass ventilation according to claim 3, characterized in that: The inlet pressure of the oxygen-enriched gas nozzle 1 is 20-40 kPa; wherein the spray angle of the oblique upper nozzle (404) is designed to be inclined at 45°-60° relative to the vertical direction.

8. The pre-combustion furnace (4) system of alternative fuel oxygen-enriched combustion coupled with bypass ventilation according to claim 1, characterized in that: The bypass ventilation design ratio of the bypass ventilation system (6) is 3%-10%, and the power of the exhaust fan (607) can be selected to be 60-200kW.

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