A combined system for self-sustaining smoldering and waste heat utilization of organic solid waste

Abstract

The present invention belongs to the field of solid waste disposal technology, and discloses a self-sustaining smoldering and waste heat utilization combined system for organic solid waste, comprising a smoldering disposal module, a flue gas waste heat utilization module, and a sand ash waste heat utilization module, wherein the smoldering disposal module comprises a smoldering furnace (1), which is provided with a flue gas outlet pipe and a slag discharge port, respectively used to output flue gas and sand ash generated by the smoldering reaction; the flue gas waste heat utilization module is used to recover the waste heat of the flue gas and output the recovered flue gas to a detachable activated carbon component; the sand ash waste heat utilization module is used to recover the waste heat of the sand ash. The present invention divides the smoldering disposal system into different modules and couples the smoldering technology with the waste heat utilization technology through the cooperative working relationship between the modules, thereby being able to fully recover the heat in the smoldering products after smoldering disposal and utilize a portion of the waste heat to achieve flue gas purification.

Description

Technical Field

[0001] The present invention belongs to the technical field of solid waste disposal, and more specifically, relates to a combined system for self-sustaining smoldering and waste heat utilization of organic solid waste. Background Art

[0002] With economic development, the production of municipal sludge and food waste in urban domestic waste has increased annually. These organic wastes have a high moisture content and are difficult to dispose of. For example, the moisture content of municipal sludge can reach over 80%, and that of food waste is generally between 70-80%. For this type of high-moisture organic waste, the main disposal methods include direct landfill, composting, and thermal treatment. Direct landfilling has been gradually phased out due to soil contamination caused by organic matter and leachate. Fermentation and composting for this type of solid waste suffers from long disposal cycles and low volume reduction rates. Among thermal treatment methods, incineration is the most mature and widely used. However, incineration often requires pretreatment such as drying and mixing with high-calorific-value fuels, resulting in relatively high disposal costs.

[0003] Smoldering combustion is a novel organic solid waste disposal technology. By mixing organic solid waste with a thermally regenerative porous medium, it enables low-temperature, flameless combustion of high-moisture content organic solid waste. Compared to traditional incineration, this process requires no continuous heat input or fuel addition, significantly reducing process energy consumption. It offers advantages such as low overall cost and simple operation.

[0004] However, the existing smoldering treatment process fails to achieve effective recovery and utilization of the waste heat of the smoldering products and mixed medium materials after treatment. The only patent CN115355512A is a self-sustaining smoldering treatment system that uses the flue gas heat for material pre-drying, thereby realizing the utilization of flue gas waste heat. Currently, there is no relevant discussion on the utilization of waste heat from solid emissions after smoldering treatment. In addition, current waste heat recovery technologies mostly use the method of drying low-temperature materials or heating industrial water, and the quality of energy conversion is low. At the same time, since smoldering flue gas contains a high concentration of volatile organic compounds (VOCs), the existing smoldering treatment system tail gas purification device mostly uses the ignition method or the adsorbent injection absorption method. During long-term operation, there are defects such as high energy consumption and large amount of adsorbent used. Summary of the Invention

[0005] In response to the above-mentioned deficiencies or improvement needs of the prior art, the present invention aims to provide a combined system for self-sustaining smoldering of organic solid waste and waste heat utilization. By improving the composition of the various modules in the system and their coordinated working relationships, and utilizing the overall coordination of the modules and the components within them, the smoldering technology and waste heat utilization technology are coupled. This system can fully recover the heat remaining in the smoldering products after smoldering treatment and utilize a portion of the waste heat for flue gas purification. The present invention utilizes the waste heat from ash in the absorption refrigeration and flue gas purification processes, converting the waste heat from ash into higher-quality energy and further enhancing the utilization value of the waste heat from ash.

[0006] To achieve the above objectives, the present invention provides a self-sustaining smoldering and waste heat utilization system for organic solid waste, which is characterized by comprising a smoldering treatment module, a flue gas waste heat utilization module and a sand ash waste heat utilization module, wherein:

[0007] The smoldering treatment module comprises a smoldering furnace (1), which is used to accommodate a mixed matrix of a porous medium and organic solid waste to be treated, and to realize a self-sustaining smoldering reaction of the organic solid waste; a smoke outlet pipeline is arranged above the smoldering furnace (1) for outputting smoke generated by the smoldering reaction; and a slag discharge port is arranged below the smoldering furnace (1) for outputting sand and ash generated by the smoldering reaction;

[0008] The flue gas waste heat utilization module is connected to the flue gas outlet pipeline and is used to recover the waste heat of the flue gas output by the smoldering furnace (1), and output the flue gas after waste heat recovery to the detachable activated carbon component to adsorb VOCs and purify the flue gas;

[0009] The sand ash waste heat utilization module is connected to the slag discharge port and is used to recover the waste heat of the sand ash output by the smoldering furnace (1).

[0010] As a further preferred embodiment of the present invention, the sand ash waste heat utilization module includes at least one of an absorption refrigeration device and an air preheating device; wherein,

[0011] The absorption refrigeration device comprises a steam generator, and the sand ash outputted by the smoldering furnace (1) can supply heat to the steam generator through heat conduction from the wall in a direct contact manner, thereby utilizing the waste heat of the sand ash;

[0012] The air preheating device comprises an air transmission pipeline, and the air transmission pipeline is used to transmit air to the smoldering furnace (1); the sand and ash output by the smoldering furnace (1) can utilize the outer wall of the air transmission pipeline to provide heat to the air transmission pipeline in a direct contact manner, thereby preheating the air and utilizing the waste heat of the sand and ash.

[0013] As a further preferred embodiment of the present invention, the air preheating device further comprises an activated carbon regeneration component for accommodating the detachable activated carbon component; the detachable activated carbon component after adsorbing VOCs can be recycled and regenerated by blowing preheated air; and the air containing VOCs enters the smoldering furnace (1) again for reaction.

[0014] As a further preferred embodiment of the present invention, the wall surface of the steam generator is funnel-shaped; the sand and ash outputted from the smoldering furnace (1) can be transported to the wall surface of the steam generator by its own gravity in a manner of symmetrical tilt on both sides, and can perform contact heat exchange with the wall surface of the steam generator.

[0015] As a further preferred embodiment of the present invention, the sand ash waste heat utilization module includes a high-temperature sand ash inlet (91) and a low-temperature slag discharge port (92), and the high-temperature sand ash inlet is connected to the slag discharge port of the smoldering furnace (1) for introducing the sand ash output from the smoldering furnace (1);

[0016] The low-temperature slag discharge port (92) is used to discharge sand and ash after waste heat utilization;

[0017] Preferably, the high-temperature sand ash feed port (91) is arranged at the top of both sides;

[0018] The low-temperature slag discharge port (92) is arranged at the bottom.

[0019] As a further preferred embodiment of the present invention, the temperature of the sand ash outputted from the smoldering furnace (1) is 100-200°C;

[0020] The temperature of sand ash after waste heat utilization does not exceed 90℃;

[0021] The temperature of the preheated air is 80-90℃.

[0022] As a further preferred embodiment of the present invention, the working fluid pair in the steam generator of the absorption refrigeration device is selected from the group consisting of water-lithium bromide working fluid pair, water-lithium chloride working fluid pair, and water-calcium chloride working fluid pair.

[0023] As a further preferred embodiment of the present invention, the flue gas waste heat utilization module comprises a condensing heat exchange tube (2) and a circulating water pool (4), wherein the circulating water pool (4) is used to provide circulating water to the condensing heat exchange tube (2); the condensing heat exchange tube (2) is respectively provided with a circulating water flow channel and a flue gas flow channel; the flue gas generated by the smoldering reaction exchanges heat with the circulating water through the flue gas flow channel in the condensing heat exchange tube (2) to obtain low-temperature flue gas;

[0024] Preferably, during the heat exchange process, liquid condensate generated by flue gas condensation can be collected through a condensate collection pool (5), and the condensate collection pool (5) is located below the condensation heat exchange tube (2) and is connected to the flue gas flow channel.

[0025] As a further preferred embodiment of the present invention, the circulating water pool (4) is further connected to a heat pump, and the water in the circulating water pool (4) is heated to a preset temperature by the heat pump and then transported to the city heating network;

[0026] Preferably, the flue gas generated by the smoldering reaction exchanges heat with the circulating water through the flue gas flow channel in the condensing heat exchange tube (2), and the temperature of the circulating water obtained after the heat exchange is 40-50° C.; the temperature of the low-temperature flue gas obtained is 50-60° C.;

[0027] The circulating water is further heated to a preset temperature, more preferably 85-95°C, by a heat pump.

[0028] As a further preferred embodiment of the present invention, the upper portion of the smoldering furnace (1) is further provided with a feed port (8) for continuously feeding a mixed matrix of the porous medium and the organic solid waste to be disposed into the smoldering furnace (1);

[0029] The outer surface of the smoldering furnace (1), the outer wall of the condensing heat exchange pipe (2) in the flue gas waste heat utilization module, and the outer wall of the sand ash waste heat utilization module are all covered with thermal insulation materials.

[0030] Through the above technical solutions conceived by the present invention, compared with the existing technology, the present invention utilizes the coordinated design of the smoldering treatment module, the flue gas waste heat utilization module and the sand ash waste heat utilization module to fully recycle and utilize the waste heat of the smoldering products while realizing low-energy consumption disposal of organic solid waste. In particular, the heat in the flue gas can be recovered for use in the urban heating network, and the heat in the sand ash can be used for absorption refrigeration or preheating of air. When the heat in the sand ash is used to preheat the air, an adsorption-saturated activated carbon component is arranged at the outlet of the air preheating pipeline, so that the adsorption-saturated activated carbon component can be regenerated and reused under the convection heat exchange and purging of the preheated air. The regenerated activated carbon component can continue to be placed at the flue gas outlet after waste heat utilization to play its role. The above design greatly reduces the floor space, equipment investment cost and operating cost of the flue gas purification components of the smoldering treatment system on the basis of realizing the purification and treatment function of the smoldering tail gas.

[0031] The smoldering reaction converts the waste to be disposed of into a mixture of sand and ash and flue gas. Unlike coal-fired boilers, where most of the heat is used for heat exchange with the tube walls and carried away by the flue gas, the resulting ash is relatively low in mass, has a low temperature, and has low waste heat utilization value. In a self-sustaining smoldering process, however, the porous medium (e.g., quartz sand) mixed with the waste to be disposed of has a high mass fraction, strong heat storage capacity, and high slag discharge temperature, resulting in extremely high waste heat utilization value. In the smoldering furnace, the waste to be disposed of is converted into high-temperature, high-moisture smoldering flue gas and high-temperature sand and ash through an oxidation reaction. The high-temperature sand and ash is the mixture of high-temperature quartz sand and smoldering ash discharged from the bottom of the smoldering furnace after the smoldering reaction. The waste heat in the high-temperature, high-moisture flue gas output by the smoldering furnace is fully recovered through circulating cooling water. After the high-moisture flue gas is condensed, the condensed smoldering waste liquid can be centrally recovered and disposed of. The circulating cooling water that has absorbed the waste heat is then heated again through a heat pump device. This secondarily heated circulating water can be used in the city heating system. After cooling, the flue gas temperature drops to room temperature, approximately 25°C, and the moisture content is low. The activated carbon adsorption component removes pollutants from the flue gas. Once the activated carbon component reaches saturation, it can be removed and replaced with a new one.

[0032] The waste heat utilization of high-temperature sand ash in the present invention can be divided into two aspects: it can provide heat for the steam generator of the absorption refrigeration device to produce cooling capacity, and it can also preheat the room-temperature air involved in the smoldering reaction and thermally desorb the pollutant gases adsorbed in the activated carbon, thereby realizing the recycling and regeneration of the activated carbon (the high-temperature sand ash output from the smoldering furnace can also be divided into two paths according to the actual usage requirements, and introduced into the steam generator and air preheating pipeline respectively, thereby realizing the above two functions at the same time). The adsorption-saturated activated carbon can be installed after the hot air duct and before the air distributor. In this way, pollutants such as volatile organic compounds (VOCs) are desorbed from the activated carbon and blown into the smoldering furnace by air for high-temperature oxidation.

[0033] The present invention can particularly utilize the waste heat of sand and ash by using an absorption refrigeration device. Unlike waste heat recovery methods with lower energy conversion quality, such as using waste heat to dry low-temperature materials or heat industrial water, the present invention can provide a cold source to the outside through an absorption refrigeration device, which has higher energy conversion quality and can save more energy consumption.

[0034] Specifically, the present invention can achieve the following beneficial effects:

[0035] 1. Considering that the temperature of the high-temperature sand and ash produced by smoldering is between 100-200°C and the temperature of the high-temperature flue gas is approximately 80°C, this invention fully recovers the waste heat contained in the flue gas and slag based on the principles of temperature matching and cascade utilization. This further improves the heat utilization rate in the smoldering system, enabling the smoldering treatment process to produce a variety of "thermal products."

[0036] 2. The system of the present invention can be used to condense the flue gas before discharging it, so that the moisture and condensable organic matter in the flue gas can be enriched, which facilitates the subsequent purification and disposal of the smoldering waste liquid. At the same time, it avoids the formation of organic aerosols in the air by components such as furan and aromatic ring organic matter, thereby reducing the pollution of the smoldering flue gas to the air.

[0037] 3. The present invention particularly utilizes a funnel-shaped steam generator wall design, with the high-temperature sand-ash heat exchange area arranged in a symmetrical, tilted pattern on both sides, and holes provided at the bottom. This design facilitates the introduction and discharge of sand and ash, increases the heat exchange area between solid particles and the wall, and reduces energy consumption of power transmission equipment such as the spiral slag discharger.

[0038] 4. The present invention couples waste heat utilization technology with the thermal desorption process of adsorption-saturated activated carbon, allowing the activated carbon component to be recycled and regenerated, thereby realizing the enrichment, translocation, and catalytic oxidation of pollutants such as VOCs in flue gas, saving the space required for flue gas purification equipment and reducing the cost required for flue gas purification.

[0039] 5. Pollutants such as VOCs and CO in smoldering flue gas have long been a bottleneck hindering the widespread adoption of this technology. Existing researchers have mostly used flue gas recirculation and the deployment of disposable activated carbon assemblies to purify flue gas, but these approaches suffer from complex piping arrangements and high disposal costs. The present invention, in particular, utilizes a sand and ash waste heat utilization module, including an air preheating device, and performs an activated carbon regeneration process within the air preheating device. This utilizes the waste heat from the product to regenerate the activated carbon assembly, offering technical advantages such as a simple structure and low flue gas purification costs.

[0040] The core of the waste heat utilization technology in this invention lies in recovering the low-grade heat energy from the waste flue gas and waste sand ash generated by the smoldering reaction. Based on the temperatures of the output flue gas and sand ash, appropriate and temperature-matched waste heat utilization methods are employed. Data from laboratory-scale and pilot-scale smoldering experiments indicate that the temperature of the discharged smoldering sand ash is generally between 100-200°C, and the temperature of the high-water content smoldering flue gas leaving the smoldering reactor is generally around 90°C. In smoldering experiments, the circulating cooling water used to condense the flue gas generally reaches a temperature of 40-50°C. Water at this temperature cannot be effectively utilized. However, heat pump technology can convert high-temperature heat sources to generate a large amount of heat with minimal power consumption. By integrating heat pump technology, this invention can cost-effectively raise the temperature of the circulating cooling water to approximately 90°C, enabling its use for urban heating. Since the discharged sand ash temperature is generally between 100-200°C, this invention utilizes it through wall heat exchange, achieving a maximum temperature of approximately 90°C for the heated working medium. As far as the heat port is concerned, the absorption refrigeration device often only needs hot water above 75°C to heat the steam generator to achieve normal operation. The thermal desorption temperature of activated carbon is also between 80-90°C. Therefore, the present invention arranges two types of working units in the sand ash waste heat utilization module, namely the steam generator and preheated air-activated carbon thermal desorption in the absorption refrigeration method. On the one hand, it can obtain a cold source with high utilization value through the waste heat of sand ash; on the other hand, it uses activated carbon as an intermediate carrier and purifies the flue gas through its own waste heat, which has a higher economic effect.

[0041] In summary, the present invention utilizes the overall coordination of various modules to effectively utilize the waste heat of the smoldering reaction and improve the environmental friendliness of the smoldering reaction; for example, by utilizing the flue gas waste heat utilization module, the circulating water temperature is raised to about 90°C through condensing flue gas heat exchange and heat pump technology, and it is used for urban heating; the cooled smoldering flue gas is purified by the activated carbon adsorption component; the sand ash waste heat can be used for preheating air and / or absorption refrigeration, and the preheated air is used to purge polluting organic gases such as VOCs in the activated carbon component into the smoldering furnace through convection heat exchange and airflow purge, so as to achieve the recycling regeneration of the activated carbon component. The present invention organically combines the smoldering disposal technology with the waste heat utilization technology, which can not only fully recover the waste heat in the smoldering products, but also effectively reduce the emission of polluting gases in the smoldering flue gas at a lower cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 It is a schematic diagram of a combined system module and process for smoldering treatment and waste heat utilization of its products provided by an embodiment of the present invention.

[0043] Figure 2 Schematic diagram of the structure of the flue gas waste heat utilization module in an embodiment of the present invention.

[0044] Figure 3Schematic diagram of the structure of the sand ash waste heat utilization module in an embodiment of the present invention.

[0045] The meanings of the reference numerals in the figure are as follows: 1. smoldering furnace; 2. condensation heat exchange pipe; 3. detachable activated carbon assembly; 4. circulating water pool; 5. condensate collection pool; 6. heat pump device; 7. urban heating network; 8. feed port; 9. sand-ash heat exchange device; 91 high-temperature sand-ash feed port; 92. low-temperature slag discharge port; 93. fixed base; 94. absorption refrigeration evaporator; 941. refrigerant; 942. refrigerant steam pipeline; 943. working fluid to solution pipeline; 944. circulating pump. DETAILED DESCRIPTION

[0046] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely for the purpose of explaining the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

[0047] like Figure 1 As shown, based on the present invention, the obtained organic solid waste self-sustaining smoldering and waste heat utilization combined system mainly includes a smoldering disposal module, a flue gas waste heat utilization module, and a sand-ash heat exchange module, wherein:

[0048] like Figure 2 As shown, similar to the smoldering device in the prior art, the smoldering furnace 1 can be mainly composed of a stainless steel reactor and a heating component and an air distribution component at the bottom of the reactor. The reactor can be cylindrical at the bottom and conical at the top.

[0049] Furthermore, a slag discharge port is located below the reactor, controlled by a valve to switch it on and off. This port is directly connected to the high-temperature sand-ash heat exchanger 9. Above the reactor of the smoldering furnace 1 are a flue gas outlet pipe and a feed port 8. The end of the reactor flue gas outlet pipe is connected to the inlet of the condensing assembly in the flue gas waste heat utilization module. The feed port can, for example, intermittently replenish the smoldering furnace with a mixed matrix containing organic and solid waste.

[0050] The flue gas waste heat utilization module is installed at the flue gas outlet to condense and purify the flue gas and recover and transfer the flue gas heat. The module primarily consists of a condenser 2, a condensate collection tank 5, a removable activated carbon adsorption assembly 3, a circulating cooling water tank 4, and a heat pump 6. It can also be connected to a heating network 7.

[0051] The high-temperature sand-ash heat exchanger 9 can be mainly composed of two working units: absorption cooling and preheating air (it is also possible to retain only one working unit according to actual needs, and not activate or set up the other working unit). The module can be installed below the slag discharge hole of the smoldering furnace, such as Figure 3 As shown, the pipeline between the low-temperature slag discharge port 92 and the high-temperature sand and ash inlet 91 of the heat exchanger is filled with a high-temperature heat exchange medium—a sand and ash mixture. The high-temperature ash inlet 91 can be located at the top of both sides of the heat exchanger to facilitate the entry of high-temperature ash into the reactor; the low-temperature slag discharge port 92 can be located at the bottom of the heat exchanger to discharge the low-temperature sand and ash.

[0052] Furthermore, the steam generator 94 of the absorption refrigeration unit is positioned above the high-temperature sand ash, and can be arranged in an obliquely symmetrical configuration. If the sand ash waste heat utilization module includes an air preheating assembly, a waste activated carbon regeneration pipeline can be further connected between the air preheating assembly and the smoldering furnace air distribution assembly. The waste activated carbon regeneration pipeline can be removably and sealedly connected to the aforementioned ends via threads.

[0053] like Figure 3 As shown, in the sand ash waste heat utilization module, the sand ash particles can enter in batches and conduct heat exchange with the air and steam generator. In specific use, the heat exchanger feed port 91 can be opened first and the bottom low-temperature slag discharge port 92 can be closed. The high-temperature sand ash particles can slowly fill the entire heat exchange device through gravity. After a period of heat exchange, according to the average reading of the heat exchanger thermocouple group, the temperature of the sand ash mixture drops to the preset temperature (such as 60°C; generally not exceeding 90°C), and then the heat exchanger feed port 91 can be closed and the bottom low-temperature slag discharge port 92 can be opened to discharge the low-temperature ash. After the sand ash in the heat exchanger is emptied, the above operation is repeated again to achieve batch heat exchange of sand ash and semi-continuous heating of air and steam generator. In addition, Figure 3 Only the steam generator of the absorption refrigeration device and the related pipeline parts connected before and after it are shown. Other components of the absorption refrigeration device can be set up with reference to the existing technology, such as the absorber, condenser, circulating pump, throttle valve, etc.

[0054] The working principle and operation process of the present invention are as follows:

[0055] First, a porous mixed matrix consisting of solid waste and an inert solid medium is fed into the smoldering furnace through a feed hole. The heating element then heats the material. When the temperature sensor at the bottom reaches a preset temperature, such as 300°C, heating is stopped and air is introduced. As the smoldering reaction proceeds, flue gases enter the condenser through an exhaust duct. Once the bottom layer of material has reacted completely and dropped to 100-200°C, the granular sand ash is drained through the slag discharge hole to the sand ash waste heat recovery module.

[0056] During the smoldering treatment process, ambient temperature circulating water undergoes multiple heat exchanges with the flue gas in the cooling pipeline, forming sub-high temperature circulating water. At this point, the water temperature is approximately 40-50°C. This sub-high temperature circulating water is then further heated to approximately 90°C via a heat pump device. After the flue gas is cooled and condensed, the condensed waste liquid is drained to the condensate collection tank 5 for centralized purification. The condensed, low-temperature, dry flue gas enters the activated carbon adsorption bed directly, removing pollutants such as VOCs from the flue gas. After a period of time, the activated carbon bed components that have reached saturation can be disassembled and updated. The condensate collection tank 5 is located below the condensation heat exchange tube 2, and the condensate is collected into the condensate collection tank 5 by gravity and drainage piping.

[0057] In this embodiment, the high-temperature sand and ash discharged from the slag discharge hole can be used in two ways: preheating the air and heating the steam generator of the absorption refrigeration unit. The preheated air, through convection heat transfer and airflow purge, thermally desorbs flue gas pollutants from the activated carbon. VOCs and other pollutants are then carried into the smoldering furnace by the airflow. This process not only promotes the recycling and regeneration of the spent activated carbon but also promotes the oxidation and heat release process within the smoldering furnace. The newly regenerated activated carbon from the thermal desorption process is removed and placed in the flue gas purification unit for use. The saturated activated carbon from the original flue gas purification unit is then replaced, and the thermal desorption and regeneration process is repeated.

[0058] The high-temperature sand and ash can also exchange heat directly with the steam generator wall. The refrigerant 941 produced in this process can be used for production and daily life in the surrounding area. The low-temperature sand and ash after heat exchange can be directly discharged through the low-temperature sand discharge hole at the bottom of the heat exchange device.

[0059] Based on the present invention, after the smoldering flue gas leaves the smoldering furnace, it directly enters the flue gas waste heat utilization module and realizes sufficient heat exchange between the flue gas and the circulating water through the condenser. The heated circulating water is then further heated using heat pump technology. The circulating water after secondary heating can be transported to the city's heating network. The circulating water temperature can be raised to 40-50°C through heat exchange with the flue gas, and the hot water temperature can reach 85-95°C after being heated by the heat pump technology. The flue gas temperature after condensation is reduced to about 60°C. The temperature of the high-temperature sand ash that supplies heat to the steam generator and preheats the air is about 100-200°C before heat exchange. The temperature of the preheated air is about 80-90°C. When the temperature of the sand ash in the heat exchanger drops to less than 90°C, the low-temperature sand ash in the heat exchanger can be discharged through the low-temperature slag discharge hole at the bottom of the heat exchanger, and another batch of high-temperature sand ash can be introduced to carry out the above-mentioned heat exchange process.

[0060] After condensation and heat exchange, the low-temperature flue gas passes through a removable activated carbon assembly for flue gas purification. The inlet of this assembly is connected to the outlet of the condenser tube, and the two are fastened with threads. Once the removable activated carbon assembly reaches saturation, it can be replaced with a new one to continue operation. The saturated activated carbon assembly is removably placed in the preheated air line, allowing pollutants such as VOCs to be thermally desorbed, achieving recycling and regeneration of the activated carbon assembly. The polluting organic gases thermally desorbed from the activated carbon are swept by hot air into the smoldering furnace, where they undergo a high-temperature oxidation reaction.

[0061] It will be easily understood by those skilled in the art that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A combined system for self-sustaining smoldering of organic solid waste and waste heat utilization, characterized in that: It includes smoldering treatment module, flue gas waste heat utilization module and sand ash waste heat utilization module, among which, The smoldering treatment module comprises a smoldering furnace (1), which is used to accommodate a mixed matrix of a porous medium and organic solid waste to be treated, and to realize a self-sustaining smoldering reaction of the organic solid waste; a smoke outlet pipeline is arranged above the smoldering furnace (1) for outputting smoke generated by the smoldering reaction; and a slag discharge port is arranged below the smoldering furnace (1) for outputting sand and ash generated by the smoldering reaction; The flue gas waste heat utilization module is connected to the flue gas outlet pipeline and is used to recover the waste heat of the flue gas output by the smoldering furnace (1), and output the flue gas after waste heat recovery to the detachable activated carbon component to adsorb VOCs and purify the flue gas; The sand ash waste heat utilization module is connected to the slag discharge port and is used to recover the waste heat of the sand ash output by the smoldering furnace (1); The sand ash waste heat utilization module includes at least one of an absorption refrigeration device and an air preheating device; wherein, The absorption refrigeration device comprises a steam generator, and the sand ash outputted by the smoldering furnace (1) can supply heat to the steam generator through heat conduction from the wall in a direct contact manner, thereby utilizing the waste heat of the sand ash; The air preheating device comprises an air transmission pipeline, the air transmission pipeline is used to transmit air to the smoldering furnace (1); the sand and ash output by the smoldering furnace (1) can utilize the outer wall of the air transmission pipeline to directly contact the air transmission pipeline to provide heat, thereby preheating the air and utilizing the residual heat of the sand and ash; The air preheating device also includes an activated carbon regeneration component for accommodating the detachable activated carbon component; the detachable activated carbon component after adsorbing VOCs can be circulated and regenerated by blowing preheated air; the air containing VOCs enters the smoldering furnace (1) again for reaction.

2. The system according to claim 1, wherein: The wall surface of the steam generator is funnel-shaped; the sand and ash outputted from the smoldering furnace (1) can be transported to the wall surface of the steam generator by its own gravity in a manner of tilting and symmetrically on both sides, and can perform contact heat exchange with the wall surface of the steam generator.

3. The system according to claim 1, wherein: The sand ash waste heat utilization module comprises a high-temperature sand ash feed port (91) and a low-temperature slag discharge port (92), wherein the high-temperature sand ash feed port (91) is connected to the slag discharge port of the smoldering furnace (1) and is used to introduce the sand ash output from the smoldering furnace (1); The low-temperature slag discharge port (92) is used to discharge sand and ash after waste heat utilization.

4. The system according to claim 3, wherein: The high-temperature sand ash feed port (91) is arranged at the top of both sides; The low-temperature slag discharge port (92) is arranged at the bottom.

5. The system according to claim 1, wherein: The temperature of the sand ash output from the smoldering furnace (1) is 100-200°C; The temperature of sand ash after waste heat utilization does not exceed 90℃; The temperature of the preheated air is 80-90℃.

6. The system according to claim 1, wherein: The working fluid pair in the steam generator of the absorption refrigeration device is selected from the water-lithium bromide working fluid pair, the water-lithium chloride working fluid pair, and the water-calcium chloride working fluid pair.

7. The system according to claim 1, wherein: The flue gas waste heat utilization module comprises a condensing heat exchange tube (2) and a circulating water pool (4), wherein the circulating water pool (4) is used to provide circulating water to the condensing heat exchange tube (2); the condensing heat exchange tube (2) is respectively provided with a circulating water flow channel and a flue gas flow channel; the flue gas generated by the smoldering reaction exchanges heat with the circulating water through the flue gas flow channel in the condensing heat exchange tube (2) to obtain low-temperature flue gas.

8. The system according to claim 7, wherein: During the heat exchange process, liquid condensate generated by flue gas condensation can be collected through a condensate collection pool (5), which is located below the condensation heat exchange pipe (2) and connected to the flue gas flow channel.

9. The system according to claim 7, wherein: The circulating water pool (4) is also connected to a heat pump, and the water in the circulating water pool (4) is heated to a preset temperature by the heat pump and then transported to the city heating network.

10. The system according to claim 9, wherein: The flue gas generated by the smoldering reaction exchanges heat with the circulating water through the flue gas flow channel in the condensing heat exchange tube (2). The temperature of the circulating water obtained after the heat exchange is 40-50° C.; the temperature of the low-temperature flue gas obtained is 50-60° C. The circulating water is further heated to the preset temperature by a heat pump.

11. The system according to claim 10, wherein: The circulating water is further heated to a preset temperature by the heat pump, that is, to 85-95°C.

12. The system according to claim 7, wherein: The upper portion of the smoldering furnace (1) is further provided with a feed port (8) for continuously feeding a mixed matrix of porous media and organic solid waste to be disposed of into the smoldering furnace (1); The outer surface of the smoldering furnace (1), the outer wall of the condensing heat exchange pipe (2) in the flue gas waste heat utilization module, and the outer wall of the sand ash waste heat utilization module are all covered with thermal insulation materials.

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