A smoldering device and quasi-stable smoldering smoke burnout method

Abstract

A kind of accumulated smoldering device and quasi-steady smoldering smoke burn-out method belong to the technical field of organic solid waste combustion such as biomass.The furnace body is closed at both ends of the cylinder, the porous medium bed is arranged in the furnace body, and the inner cavity of the furnace body is divided into the combustion chamber (14) on the upper side and the cyclone chamber (8) on the lower side, the smoldering box (1) is provided with several, each smoldering box (1) is communicated with the cyclone chamber (8) through the smoke inlet (3), each smoke inlet (3) is arranged along the tangent direction of the cyclone chamber (8), the cyclone chamber (8) is also connected with the oxygen supply device, and the top of the furnace body is provided with the discharge port, the discharge port is connected with the heat recovery device.The accumulated smoldering device and quasi-steady smoldering smoke burn-out method can achieve different scales of accumulated smoldering in industry to reach quasi-steady state;It can burn out combustible gas in low-calorific-value smoke and particulate matter that needs to be burned out for a long time under the condition that the whole equipment has small volume and low energy consumption, and economically solve the problems of smoldering steady state and smoke burn-out.

Description

Technical Field

[0001] A smoldering stacking device and a quasi-steady-state smoldering smoke burnout method belong to the field of biomass and other organic solid waste combustion technology. Background Technology

[0002] The world produces approximately 170 billion tons of biomass annually, 4.5 times the total global primary energy consumption in 2020. my country is also rich in agricultural and forestry biomass resources, producing 800 million tons of crop straw and approximately 1 billion tons of forestry biomass waste such as timber processing and fruit tree branches annually. Smoldering is combustion without flame; the application of biomass smoldering for heating (combustion pits, heated floors, hand warmers, etc.) is a traditional technology in my country. Currently, smoldering is also commonly used in the treatment of organic solid waste (CN202011604933.3, CN201711449927.3). Using smoldering combustion to treat and apply organic solid waste such as biomass has many advantages: such as 1) high moisture content and low calorific value fuel can be used directly; 2) the combustion process is slow and can be matched with heating; 3) potassium, sodium or heavy metals in organic solid waste are fixed in ash due to the low temperature of the combustion bed and the filtration effect, which not only prevents the heat exchange equipment from being contaminated and corroded, but also makes it easy to recover heavy metals from the ash. Biomass ash can also be used as fertilizer for returning to the field.

[0003] However, most smoldering combustion is characterized by abundant smoke, mainly composed of CO, CH4, H2, NH3, tar, and soot, containing a large amount of particulate matter, with a lower calorific value of 1.0-7.8 MJ / Nm³. 3 It is a low-calorific-value gas (WynHK et al. Self-sustaining smouldering combustion of waste: A review on applications, key parameters and potential resource recovery, Feul processing technology 2020), and is generally not easy to ignite and not easy to burn stably.

[0004] Patent CN201910522702.9 discloses a device for smoldering treatment and flue gas purification of organic solid waste, including a reactor, a smoldering igniter, a gas igniter, an air intake assembly, and a monitoring system. The gas igniter is used to ignite the smoke generated by smoldering to achieve smoke purification. Patent CN202110659932.7 discloses a combustion method for biomass stockpiling smoldering and electrically heated flue gas combustion. Smoldering avoids coking and slagging of high-potassium biomass fuel, and electric heating is used to assist in the complete combustion of biomass smoldering flue gas, reducing pollutant emissions. However, these smoldering devices are batch-type, with significant differences in operating conditions at the beginning, middle, and end stages. For a considerable period, the smoke is difficult to ignite and sustain combustion. Furthermore, the smoldering smoke contains a high particulate matter content; even if it can ignite and burn, a long residence time is required for complete combustion, necessitating a very large smoke combustion chamber.

[0005] To achieve continuous smoldering, patent 202110791321.8 discloses a skid-mounted solid waste smoldering treatment system and method. The system includes a feeding system, a discharging system, a hydraulic system, a heating and air supply system, a flue gas system, and at least two skid-mounted smoldering reactors; large-scale continuous treatment of smoldering is achieved by alternating operation of at least two structurally simple skid-mounted smoldering reactors. Patent CN202210601225.7 discloses a semi-continuous horizontal self-sustaining smoldering reactor and method, the smoldering furnace including a furnace body and a spiral agitator, capable of batch treatment of high-moisture organic solid waste. Although these smoldering technologies achieve semi-continuous treatment, the operating state during the smoldering process still varies greatly. Due to the significantly unsteady process, the operation and application of subsequent equipment remain difficult, especially the treatment of smoke burnout, which remains a major challenge.

[0006] Patent 202010946480.6 discloses a smoldering equipment and method for treating organic pollutants on a production line. The equipment includes a loading device, a smoldering reaction device, and a unloading device arranged sequentially. The smoldering reaction device includes a support frame, a support rail, a smoldering chamber, a gas collection device, a ventilation and heating base plate, and a ventilation base plate. The smoldering chamber is placed on the support rail and moves axially along the support rail, with its top communicating with the gas collection device. The support rail is divided into a smoldering start-up zone and a continuous reaction zone from front to back along the direction of travel of the smoldering chamber. The ventilation and heating base plate is placed at the projection position of the smoldering chamber in the smoldering start-up zone and heats and ignites the material inside the smoldering chamber, achieving separation and sharing between the ventilation and heating base plate and the smoldering chamber, and maintaining continuous operation. The ventilation base plate is placed at the bottom of the support rail and communicates with the interior of the smoldering chamber, maintaining self-sustaining combustion of the material. This invention has the advantages of high automation, high degree of assembly line operation, and high production efficiency. The device has a complex guide rail structure, many moving parts, and is difficult to troubleshoot. It is also difficult to scale up or down, and the very important smoke treatment is not mentioned.

[0007] The main problem with smoldering technology is that most smoldering processes are clearly unsteady-state processes, producing substances containing CO, CH4, and C. x H y The smoke, composed of particles such as soot, tar, etc., is constantly changing. Smoldering smoke itself has a relatively low calorific value, and when its composition changes over a wide range, it is very difficult to treat. If it is not treated thoroughly and is discharged, it wastes energy and pollutes the environment.

[0008] Porous media is a novel combustion technology developed in recent years, characterized by high combustion efficiency, easy combustion of low-calorific-value gases, and NO. x Advantages include low emissions, simple structure, and low cost. Patent 202210632003.1 provides a multi-layer porous media burner and its preparation method, suitable for low-concentration and low-calorific-value combustion gases. Patent 201110183845.5 discloses a porous media burner for burning low-calorific-value gaseous fuels, employing segmented porous media, which can significantly improve the combustion stability of low-calorific-value gaseous fuels. Porous media are also used to filter and adsorb particulate matter in fluids. Patent CN201620879237.6 discloses a purification filter for treating the exhaust gas emitted from an activated carbon furnace; the porous media filter in this filter can remove residual fine carbon powder from the fuel gas, achieving efficient purification of the exhaust gas. However, a technology that can simultaneously filter and deposit solid and liquid phase particulate matter in the smoke, stably burn the deposited particulate matter, and simultaneously burn the combustible gas in the gas phase is currently unreported.

[0009] The main problems currently facing smoldering and the burnout of smoldering smoke are: 1) Smoldering in most industrial applications is a non-steady-state process, making application and smoke treatment very difficult. 2) Because smoldering smoke consists of low-calorific-value gases containing a large amount of particulate matter, even if the smoldering is stable, the burnout of the particles requires a long residence time, necessitating very large smoke burnout devices, resulting in high equipment costs, significant heat loss, and high operation and maintenance costs. If the smoldering is unstable, the flue gas is even more difficult to treat. In general, there is a lack of economical and reliable smoldering stable combustion equipment and technologies that can simultaneously burn out smoldering smoke particles and combustible gases. Summary of the Invention

[0010] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a smoldering device and a quasi-steady-state smoldering smoke burnout method to achieve quasi-steady-state smoldering at different scales in industrial applications, while economically solving the problems of smoldering steady state and smoke burnout.

[0011] The technical solution adopted by the present invention to solve its technical problem is as follows: the stacked smoldering device is characterized by comprising a furnace body, smoldering boxes, and a porous media bed. The furnace body is a cylinder with both upper and lower ends closed. The porous media bed is arranged inside the furnace body and divides the inner cavity of the furnace body into an upper combustion chamber and a lower swirl chamber. Several smoldering boxes are provided, and each smoldering box is connected to the swirl chamber through a smoke inlet. Each smoke inlet is arranged along the tangential direction of the swirl chamber. The swirl chamber is also connected to an oxygen supply device. An exhaust port is provided at the top of the furnace body, and the exhaust port is connected to a heat recovery device.

[0012] Preferably, a smoke channel valve is provided between each of the smoldering boxes and the swirl chamber.

[0013] Preferably, the oxygen supply device includes a gas inlet pipe, a gas inlet regulating valve, an oxygen measuring element, and an oxygen controller. The outlet end of the gas inlet pipe is connected to the vortex chamber, and the inlet of the gas inlet pipe is connected to the atmosphere or to an oxygen-enriched tank. The gas inlet regulating valve is installed on the gas inlet pipe. The oxygen measuring element is installed at the output port of the heat recovery device. The signal output end of the oxygen measuring element is connected to the signal input end of the oxygen controller. The oxygen controller is connected to the gas inlet regulating valve.

[0014] Preferably, the porous media bed includes a support plate, porous media filler, heating element, thermometer, and temperature controller. The support plate is fixedly connected to the inner cavity of the furnace. The porous media filler is disposed on the upper side of the support plate. The support plate is a mesh plate. The heating element and the thermometer are both disposed inside the porous media filler. The signal output terminal of the thermometer is connected to the signal input terminal of the temperature controller. The temperature controller is connected to the heating element.

[0015] Preferably, the pore size of the porous media packing is arranged in a gradual decreasing manner along the direction of smoke flow in the bed.

[0016] Preferably, the distance between the heating element and the support plate is 2-5 cm.

[0017] A method for quasi-steady-state smoldering smoke burnout of the above-mentioned smoldering stacking device includes the following steps:

[0018] 1) Each smoldering box is fed, ignited, and ash discharged sequentially at the same time intervals to achieve a quasi-steady state of smoldering;

[0019] 2) The smoldering smoke mixes with oxygen or air in the swirling chamber, and the particulate matter is filtered and deposited as it flows through the porous media bed. The combustible gas enters the combustion chamber and burns completely, thus achieving complete combustion of the smoke.

[0020] Preferably, during the feeding, ignition, and ash removal processes, the interface between the smoldering box and the vortex chamber is closed.

[0021] Preferably, the smoke in step 2) remains in the combustion chamber for more than 2 seconds.

[0022] Preferably, the swirling chamber and combustion chamber are maintained under negative pressure.

[0023] Compared with the prior art, the beneficial effects of this invention are:

[0024] This smoldering device and quasi-steady-state smoldering smoke burnout method can achieve quasi-steady-state combustion in industrial smoldering of different scales. It can burn out combustible gases and particulate matter requiring long-term combustion in low-calorific-value smoke while maintaining a relatively small overall equipment size and low energy consumption. Therefore, it economically solves both the smoldering steady-state problem and the smoke burnout problem simultaneously. Attached Figure Description

[0025] Figure 1 This is a structural schematic diagram of a smoldering stacking device;

[0026] Figure 2 Schematic diagram of the swirling arrangement of the smoke inlet;

[0027] Figure 3 Connection diagram for centralized arrangement of smoldering boxes;

[0028] Figure 4 Connection diagram for the dispersed arrangement of smoldering boxes;

[0029] Figure 5 The principle of achieving quasi-steady-state smoldering through sequential ignition of smoldering box arrays.

[0030] In the diagram: 1. Smoldering box; 2. Smoke passage valve; 3. Smoke inlet; 4. Gas inlet pipe; 5. Gas inlet regulating valve; 6. Oxygen measuring element; 7. Oxygen controller; 8. Swirl chamber; 9. Support plate; 10. Porous media packing; 11. Heating element; 12. Thermometer; 13. Temperature controller; 14. Combustion chamber; 15. Smoke swirl outlet; 16. Refractory insulation layer; 17. Outer shell; 18. Heat exchanger; 19. Smoke exhaust fan; 20. Oxygen enrichment tank. Detailed Implementation

[0031] The present invention will be further described below with reference to specific embodiments. However, those skilled in the art should understand that the detailed description given here with reference to the accompanying drawings is for better explanation. The structure of the present invention necessarily exceeds the limited embodiments described herein. Some equivalent alternatives or common means will not be described in detail here, but still fall within the protection scope of this application.

[0032] Figures 1-5 This is the preferred embodiment of the present invention, which is described below in conjunction with the accompanying drawings. Figures 1-5 The present invention will be further described below.

[0033] A smoldering stacking device includes a furnace body, smoldering chambers 1, and a porous media bed. The furnace body is a cylinder sealed at both ends. The porous media bed is disposed within the furnace body, dividing the furnace interior into an upper combustion chamber 14 and a lower swirl chamber 8. Several smoldering chambers 1 are provided, each connected to the swirl chamber 8 via a smoke inlet 3. Each smoke inlet 3 is arranged tangentially to the swirl chamber 8. The swirl chamber 8 is also connected to an oxygen supply device. An exhaust port is provided at the top of the furnace body, connected to a heat recovery device. This smoldering stacking device and quasi-steady-state smoldering smoke burnout method can achieve quasi-steady-state smoldering at different scales in industrial applications. It can burn out combustible gases and particulate matter requiring long-term burnout in low-calorific-value smoke while maintaining a small overall equipment size and low energy consumption. Therefore, it economically solves both the smoldering steady-state problem and the smoke burnout problem simultaneously.

[0034] Specifically: such as Figure 1 As shown: The furnace body includes a refractory insulation layer 16 and an outer shell 17. The outer shell 17 is a cylinder that is closed at both the top and bottom. The refractory insulation layer 16 is set on the inner wall of the outer shell 17. The refractory insulation layer 16 is composed of refractory bricks and insulation bricks. The outer shell 17 plays a supporting and sealing role.

[0035] The number of smoldering boxes 1 should be at least three, preferably 4 to 12. For small-scale operations or when the requirements for quasi-steady-state performance are not high, a smaller number can be used, while for large-scale operations or when the requirements for quasi-steady-state performance are high, a larger number can be used.

[0036] Each smoldering chamber 1 is connected to the swirl chamber 8 via a smoke inlet 3, and each smoke inlet 3 is distributed on a circle coaxial with the swirl chamber 8. A smoke channel valve 2 is provided between each smoldering chamber 1 and the smoke inlet 3 to facilitate the control of the opening and closing of the connection between the smoldering chamber 1 and the smoke inlet 3. The number of multiple smoke inlets 3 corresponds to the number of smoldering chambers 1; through swirl, good mixing of air (or oxygen-enriched gas) and smoke is ensured, which is conducive to the subsequent complete combustion of smoke.

[0037] The oxygen supply device includes a gas inlet pipe 4, a gas inlet regulating valve 5, an oxygen measuring element 6, and an oxygen controller 7. The outlet end of the gas inlet pipe 4 is connected to the vortex chamber 8, and the inlet of the gas inlet pipe 4 is connected to the atmosphere or to the oxygen enrichment tank 20. The gas inlet regulating valve 5 is installed on the gas inlet pipe 4. The oxygen measuring element 6 is installed at the output port of the heat recovery device. The signal output end of the oxygen measuring element 6 is connected to the signal input end of the oxygen controller 7. The oxygen controller 7 is connected to the gas inlet regulating valve 5.

[0038] One end of the gas inlet pipe 4 is connected to the atmosphere or the oxygen-enriched cylinder 20, and the other end is connected to the gas inlet pipe regulating valve 5. The pipe after the gas inlet pipe regulating valve 5 is connected to the vortex chamber 8. The oxygen measuring element 6 is placed at the flue gas outlet of the device and connected to the oxygen controller 7.

[0039] The porous media bed module consists of a support plate 9, porous media packing 10, an electric heating element 11, a thermometer 12, and a temperature controller 13. The support plate 9 separates the vortex chamber 8 from the porous media packing 10 and supports the packing. The porous media bed packing 10 is placed above the support plate 9, and the pore size of the bed should be selected according to the size of the smoke particles to filter smoke particles deposited at a rate of 90 wt% or higher. The electric heating element 11 is fixed within the gradually varying porosity porous media packing 10, at a distance of 2-5 cm from the support plate 9. The maximum temperature of the electric heating element 11 can reach over 550℃, used to assist in heating and burning off the particles deposited on the porous media packing 10. The signal output terminal of the thermometer 12 is connected to the signal input terminal of the temperature controller 13, which is connected to the electric heating element 11. The thermometer 12 is placed on the upper surface of the electric heating element 11, and the surface temperature of the electric heating element 11 is measured by the thermometer 12 and controlled by the temperature controller 13.

[0040] The heat recovery device includes an exhaust fan 19 and a heat exchanger 18. The heat exchanger 18 is a shell-and-tube heat exchanger. The exhaust port of the combustion chamber 14 is connected to the tube-side inlet of the heat exchanger 18, and the air inlet of the exhaust fan 19 is connected to the tube-side outlet of the heat exchanger 18. The heat of the exhaust gas is recovered by the medium flowing through the shell side of the heat exchanger 18. The combustion chamber 14 is connected to the tube-side inlet of the heat exchanger 18 through a flue gas swirl outlet 15.

[0041] Combustion chamber 14 is downstream of porous media packing 10. Combustion chamber 14 rotates towards external flue gas swirl outlet 15 to form a swirl, which promotes the complete combustion of combustible flue gas.

[0042] like Figure 2 As shown. The smoldering tank 1 can be large or small. A small smoldering tank 1 can hold a few kilograms of fuel, and the fuel in a single smoldering tank 1 can burn for several hours. A large smoldering tank 1 can hold tens of tons of fuel, and the fuel in a single smoldering tank 1 can burn for tens of days. Generally, small-scale operations are flexible and can handle a variety of organic solid wastes, while large-scale operations are more economical and can handle large quantities of solid waste.

[0043] The smoldering boxes 1 can be arranged in a centralized manner or dispersed according to the application. Centralized arrangement is as follows: Figure 3 As shown, it can be used for the treatment of municipal solid waste or toxic organic solid waste from enterprises. The entire unit, arranged centrally, is housed within a single building, with the building's environmental requirements determined by the type of waste being treated. A dispersed arrangement is also possible. Figure 4As shown, the smoke generated by each smoldering furnace 1 needs to be collected and treated together through pipelines, which can be used for heating in greenhouses, livestock sheds, and rural industrial areas. For greenhouse applications, each smoldering furnace 1 can be placed in each greenhouse to burn biomass waste generated during smoldering; the smoldering furnace 1 can also act as a radiator in the greenhouse; the generated ash can be used as greenhouse fertilizer. For livestock shed applications, each smoldering furnace 1 can be placed in each independent livestock shed to burn cow dung or waste biomass; the smoldering furnace can also act as a radiator, and the ash can be used to disinfect the livestock shed. A similar arrangement can be used for heating in rural industrial areas. In the above applications, the air inlet of the smoldering furnace 1 must be led outdoors, and the smoldering furnace 1 must be sealed to prevent smoke leakage into the room. In addition, the heat generated by the centralized combustion of smoke is transported to offices, greenhouses, and livestock sheds that require heating after passing through a heat exchanger.

[0044] The present invention also provides a quasi-steady-state smoldering smoke burnout method for the above-mentioned smoldering stacking device, comprising the following steps:

[0045] 1) Each smoldering box 1 is fed, ignited and ash is discharged sequentially at the same time interval, thereby achieving a quasi-steady state of smoldering.

[0046] Specifically, multiple identical smoldering boxes 1 are fed, ignited, and have ash removed in a regular sequence at certain time intervals to achieve a quasi-steady state of smoldering. The time intervals are flexibly determined based on the scale and duration of use, and can be increased or decreased as required during operation. For example, in heating systems, the smoldering intensity can be adjusted according to the ambient temperature, thereby changing the time intervals.

[0047] The principle of achieving quasi-steady-state smoldering using smoldering box arrays is as follows: Figure 5 As shown, in this embodiment, six smoldering boxes 1 are set. When each smoldering box 1 operates independently, the approximate rate of fuel consumption and smoke generation is represented by the blue dashed line curve at the bottom right of the figure. Each rate rises from zero to its maximum value, then drops back to zero, with a fluctuation range of 100% of the maximum value. After using the smoldering box 1 array and sequentially adding, igniting, and removing ash, the overall fuel consumption and smoke generation rate patterns are as follows: Figure 5 As shown by the solid curve above, the temperature fluctuates periodically from zero during the first ignition cycle of the smoldering furnace. After the sixth smoldering furnace starts up, it fluctuates according to the same pattern, with a fluctuation range of 15.5% of the maximum value. For each piece of equipment, an overlay diagram should be drawn to select and determine the appropriate design.

[0048] During the feeding, ignition, and ash removal processes of the smoldering box 1, the smoke passage valve 2 between the smoldering box 1 and the swirl chamber 8 is closed to prevent smoke leakage. Each smoldering box 1 can be operated independently, and its gas inlet and outlet can be completely shut off. If a smoldering process in a particular smoldering box 1 malfunctions, its gas inlet and outlet can be completely shut off to isolate that smoldering box 1. If a system-wide malfunction occurs, all inlets and outlets can be closed to temporarily isolate or extinguish the smoldering process and resolve the fault.

[0049] The smoldering box 1 can be moved outdoors for ash discharge and material feeding to reduce indoor dust.

[0050] It can be combined with robots to achieve machine material changing, and is particularly suitable for handling toxic pollutants.

[0051] 2) The smoldering smoke is mixed with oxygen or air in the swirling chamber 8. The particulate matter in the mixture is filtered and deposited as it flows through the porous media bed. The combustible gas enters the burnout chamber 14 and burns out, thus achieving complete combustion of the smoke.

[0052] The smoke generated in the smoldering chamber 1 first mixes with oxygen from air or oxygen-enriched gas in the swirl chamber 8. Then, the particulate matter in the mixture is filtered or deposited on the surface of the porous media packing 10 as it flows through, and is rapidly burned off by the electric heating element 11 to above 400°C. Finally, the combustible gas in the mixture is burned off in the combustion chamber 14. The smoke resides in the combustion chamber 14 for more than 2 seconds to ensure complete combustion of the combustible gas. Because the particulate matter with a long combustion time can remain in the porous media packing 10 for a long time, a large combustion volume is not required, thus achieving efficient combustion of small-volume smoke. In the quasi-steady-state combustion method, the equipment operates under a slight negative pressure, and an exhaust fan 10 is installed at the flue gas outlet of the device.

[0053] In the quasi-steady-state smoldering smoke combustion method, the oxygen required for smoke combustion can come from either air or oxygen-enriched gas. The intake air volume or oxygen-enriched gas volume of the device is adjusted according to the overall exhaust oxygen concentration. Using oxygen-enriched gas helps with smoke combustion and also reduces the electrical energy consumption of the heating element 11. Especially for some toxic solid organic substances, using oxygen-enriched gas is more conducive to the complete combustion of toxic gases.

[0054] Based on the results measured by the oxygen measuring element 6, the oxygen controller 7 controls the opening of the gas inlet pipe regulating valve 5 to achieve reasonable oxygen distribution.

[0055] The quasi-steady-state smoldering smoke burnout method utilizes the electric heating element 11, which assists in the burnout of particulate matter within a porous medium. The maximum temperature can reach over 550°C. A suitable temperature is set and controlled by a temperature controller. Electric heating is only activated when the temperature is insufficient, reducing energy consumption. Due to the large specific surface area of ​​charcoal smoke, it generally burns at temperatures above 350°C, and the combustion rate can be relatively fast at 450°C.

[0056] The electric heating element 11 can be a silicon carbide rod or a carbon fiber heating tube, with a heating temperature of 450~550℃, so that the deposited combustible particles can be quickly ignited and burned.

[0057] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A method for quasi-steady-state smoldering smoke burnout of a smoldering stacking device, characterized in that: The stacked smoldering device includes a furnace body, a smoldering box (1), and a porous medium bed. The furnace body is a cylinder that is closed at both the top and bottom. The porous medium bed is set inside the furnace body and divides the inner cavity of the furnace body into an upper combustion chamber (14) and a lower swirl chamber (8). There are several smoldering boxes (1). Each smoldering box (1) is connected to the swirl chamber (8) through a smoke inlet (3). Each smoke inlet (3) is set along the tangential direction of the swirl chamber (8). The swirl chamber (8) is also connected to an oxygen supply device. The top of the furnace body is provided with an outlet, which is connected to a heat recovery device. The porous media bed includes a support plate (9), a porous media packing (10), an electric heating element (11), a thermometer (12), and a temperature controller (13). The support plate (9) is fixedly connected to the inner cavity of the furnace. The porous media packing (10) is set on the upper side of the support plate (9). The support plate (9) is a mesh plate. The electric heating element (11) and the thermometer (12) are both set inside the porous media packing (10). The signal output end of the thermometer (12) is connected to the signal input end of the temperature controller (13). The temperature controller (13) is connected to the electric heating element (11). The method includes the following steps: 1) Each smoldering box (1) is fed, ignited and ash is discharged in sequence at the same time interval, so as to achieve a quasi-steady state of smoldering; 2) The smoldering smoke mixes with oxygen or air in the swirling chamber (8), and the particulate matter is filtered and deposited as it flows through the porous media bed. The combustible gas enters the combustion chamber (14) and burns out, thus achieving complete combustion of the smoke.

2. The quasi-steady-state smoldering smoke burnout method for a smoldering stacking device according to claim 1, characterized in that: Each of the aforementioned smoldering boxes (1) and swirl chambers (8) is provided with a smoke channel valve (2).

3. The quasi-steady-state smoldering smoke burnout method for a smoldering stacking device according to claim 1, characterized in that: The oxygen supply device includes a gas inlet pipe (4), a gas inlet regulating valve (5), an oxygen measuring element (6), and an oxygen controller (7). The outlet of the gas inlet pipe (4) is connected to the vortex chamber (8), and the inlet of the gas inlet pipe (4) is connected to the atmosphere or to the oxygen-enriched tank (20). The gas inlet regulating valve (5) is installed on the gas inlet pipe (4). The oxygen measuring element (6) is installed at the output port of the heat recovery device. The signal output end of the oxygen measuring element (6) is connected to the signal input end of the oxygen controller (7). The oxygen controller (7) is connected to the gas inlet regulating valve (5).

4. The quasi-steady-state smoldering smoke burnout method for the smoldering stacking device according to claim 1, characterized in that: The pore size of the porous media packing (10) is arranged in a gradual manner from large to small along the direction of smoke flow in the bed.

5. The quasi-steady-state smoldering smoke burnout method for a smoldering stacking device according to claim 1, characterized in that: The distance between the heating element (11) and the support plate (9) is 2-5 cm.

6. The quasi-steady-state smoldering smoke burnout method for a smoldering stacking device according to claim 1, characterized in that: During the feeding, ignition and ash removal process, the interface between the smoldering box (1) and the swirl chamber (8) is closed.

7. The quasi-steady-state smoldering smoke burnout method for a smoldering stacking device according to claim 1, characterized in that: The smoke in step 2) remains in the combustion chamber (14) for more than 2 seconds.

8. The quasi-steady-state smoldering smoke burnout method for a smoldering stacking device according to claim 1, characterized in that: The swirling chamber (8) and the combustion chamber (14) are maintained under negative pressure.

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