A system and method for improving thermal efficiency of organic solid waste disposal

Abstract

The application discloses a system and method for improving heat efficiency of organic solid waste treatment. The system comprises a drying system, a sealed feeding system, a gasification melting system, a combustion system and a slag discharging system. The sealed feeding system is connected between the drying system and the gasification melting system. The drying system is connected with the combustion system. The gasification melting system is connected with the combustion system. The slag discharging system comprises a water quenching system capable of providing high-pressure water and a heat exchange system. The liquid molten slag inlet of the water quenching system is connected with the liquid molten slag outlet of the gasification melting system. The water vapor outlet of the water quenching system is connected with the gasification agent inlet of the gasification melting system and the other outlet is connected with the heat exchange system. The heat exchange system is connected with the combustion system. The water quenching water vapor is used as the gasification agent and is exchanged with air through the heat exchange system to output hot air, so that the gasification efficiency of fixed carbon is improved, the hydrogen content in the crude synthetic gas is improved, the added value of the crude synthetic gas is improved, the waste heat is utilized and the system heat efficiency is improved.

Description

Technical Field

[0001] This invention relates to a method and system for treating organic solid waste, and more particularly to a system and method for improving the thermal efficiency of organic solid waste disposal. Background Technology

[0002] Currently, the main methods for treating organic solid waste include landfill, incineration, physical methods, and chemical methods. However, most of these methods suffer from problems such as incomplete harmless treatment, high treatment costs, and secondary pollution to the environment.

[0003] Gasification melting is a process in which organic solid waste undergoes partial combustion under controlled oxygen (air) supply to achieve gasification, generating combustible gases, while simultaneously melting fly ash and bottom ash. This technology can more efficiently recover resources and energy from organic solid waste, while meeting stricter emission standards for organic solid waste, maximizing the harmlessness and resource utilization of hazardous solid waste, and avoiding secondary pollution. It is a very promising method for the disposal of organic solid waste.

[0004] Patent CN105605581A discloses a vertical waste gasification and melting furnace. Waste enters the furnace body through a top-feeding device and moves downwards within the vertical furnace. Through heat exchange with rising high-temperature gas, the waste gradually dries and pyrolyzes, generating combustible gas and ash. The ash further moves downwards into the combustion zone below, achieving gasification and melting. This process is simple, has good system sealing, and high heat utilization. However, in actual projects, the moisture content and organic matter content of the organic solid waste entering the furnace are unstable, and the heat required for drying and pyrolysis, as well as the heat generated by the remaining fixed carbon, cannot be controlled, leading to unstable temperatures in the melting section and problems such as unstable system operation.

[0005] Patent CN 108097703A discloses a plasma gasification and melting system for centralized solid waste treatment. Through a heat exchanger and waste heat recovery system, it effectively utilizes the sensible heat of the high-temperature gas generated by the system and uses a grate furnace to dry and gasify the solid waste. Only the generated ash is subjected to high-temperature plasma melting treatment, avoiding the direct use of plasma for drying, pyrolysis, and gasification of solid waste, thus effectively reducing system energy consumption. However, this system uses a heat exchanger for waste heat recovery, and the tar and dust contained in the crude syngas easily clog the heat exchange equipment, resulting in low heat exchange efficiency and a high failure rate. Simultaneously, after heat exchange, the air directly enters the grate, making it impossible to effectively control the temperature and flow rate according to changes in raw materials. After gasification, the solid waste still needs to be heated by plasma to reach the melting temperature in the melting furnace, indicating that the system's thermal efficiency needs further improvement.

[0006] Existing high-temperature melting gasification technology has basically achieved the harmlessness, reduction, stabilization, and resource utilization of organic solid waste, and is environmentally friendly, but there are still many shortcomings. For example, the system has low thermal utilization rate, high energy consumption, and difficulty in controlling the gas entering the furnace and the reducing atmosphere inside the furnace, which requires further optimization of the system. Summary of the Invention

[0007] Purpose of the invention: The purpose of this invention is to provide a system for improving the thermal efficiency of organic solid waste treatment, which has high system thermal utilization rate, low energy consumption, and easy control of the gas entering the furnace and the reducing atmosphere inside the furnace.

[0008] The second objective of this invention is to provide a method for improving the thermal efficiency of organic solid waste disposal.

[0009] Technical Solution: The system for improving the thermal efficiency of organic solid waste treatment according to the present invention includes a drying system, a sealed feeding system, a gasification and melting system, a combustion system, and a slag discharge system. The sealed feeding system is connected between the discharge port of the drying system and the inlet of the gasification and melting system. The high-temperature flue gas inlet of the drying system is connected to the high-temperature flue gas outlet of the combustion system, and the flue gas outlet after heat exchange is connected to the circulating air inlet of the combustion system. The crude syngas outlet of the gasification and melting system is connected to the crude syngas inlet of the combustion system. The slag discharge system includes a water quenching system that can provide high-pressure water and a heat exchange system. The liquid slag inlet of the water quenching system is connected to the liquid slag outlet of the gasification and melting system, and is used to rapidly cool and heat the liquid slag through the high-pressure water of the water quenching system to generate water vapor. The water vapor outlet of the water quenching system has two outlets, one connected to the gasifying agent inlet of the gasification and melting system and the other connected to the water vapor inlet of the heat exchange system. The hot air outlet of the heat exchange system is connected to the primary air inlet of the combustion system, and is used to send the hot air generated after heat exchange between the air and the water vapor into the combustion system.

[0010] The gasification and melting system includes a gasification and melting furnace, which comprises an upper pyrolysis and gasification section and a lower melting section. The upper part of the pyrolysis and gasification section is the pyrolysis section, and the lower part is the gasification section. The pyrolysis and gasification section is provided with a gasification and melting system inlet, a gasifying agent inlet, and a crude syngas outlet connected to a sealed feeding system. The melting section is provided with an oxygen-enriched air inlet, a liquid slag outlet, and a heavy metal outlet.

[0011] The combustion system includes a low-NOx combustion furnace connected to an independent burner; the combustion furnace is provided with a crude syngas inlet, a primary air inlet, a circulating air inlet, and a high-temperature flue gas outlet; the crude syngas inlet is connected to the crude syngas outlet of the gasification and melting system; the primary air inlet is connected to the hot air outlet of the heat exchange system; the circulating air inlet is connected to the heat exchanged flue gas outlet of the drying system; and the high-temperature flue gas outlet is connected to the high-temperature flue gas inlet.

[0012] The independent burner and the primary air inlet are arranged symmetrically, one above the other, and the crude syngas inlet and the independent burner and the primary air inlet are arranged perpendicularly.

[0013] The circulating air inlet is located at the tail end of the low-NOx combustion furnace; the crude syngas inlet is located at the head end of the low-NOx combustion furnace.

[0014] The water quenching system also includes a water storage tank for solid slag connected to the liquid slag inlet, a high-pressure water jet gun located above the water storage tank, and a gas collection hood; the gas collection hood is used to collect the generated water vapor; the water vapor outlet is located on the gas collection hood.

[0015] The gas collection hood is equipped with several atomizing nozzles connected to the water storage and solid slag storage tank via pipelines.

[0016] The heat exchange system is also equipped with an air inlet and a condensate outlet; the condensate outlet is connected to a water storage tank for solid waste.

[0017] The drying system includes a rotary dryer, which comprises a kiln head, a kiln body, and a kiln tail. The kiln head has a raw material inlet connected to a screw feeder and a kiln head flue gas inlet. The kiln body includes an outer cylinder, an inner cylinder, and a ring system formed by the outer and inner cylinders. The kiln tail has an evaporation water outlet, a drying system outlet, and a material temperature tester. The outer cylinder has a high-temperature flue gas inlet and a heat-exchange flue gas outlet. The kiln head flue gas inlet is connected to the heat-exchange flue gas outlet. The inner cylinder has a spiral baffle to guide the material effectively and increase the heating area. The heat-exchange flue gas outlet has two pipelines, one of which is connected to the circulating air inlet of the combustion furnace, and the other is connected to the flue gas inlet of the kiln head. After further utilization of waste heat, the gas passes through a tail gas purification system and finally meets emission standards.

[0018] The sealed feeding system includes a feeding pipe that is sequentially connected to the outlet of the drying system and the inlet of the gasification and melting system. An upper locking valve and a lower locking valve are respectively located near the outlet of the drying system and the inlet of the gasification and melting system on the feeding pipe. A locking chamber is formed between the upper and lower locking valves. The feeding pipe is equipped with an arch-breaking device for rotating the material within the feeding pipe. The arch-breaking device is connected between the upper and lower locking valves via upper and lower flanges, respectively. The arch-breaking device includes an arch-breaking ring that fits against the feeding pipe and rotates around a horizontal axis. A drive motor is connected to the arch-breaking ring. The feeding pipe is equipped with an auxiliary fuel inlet. The feeding pipe is positioned vertically below the tail of the rotary dryer kiln.

[0019] The method for improving the thermal efficiency of organic solid waste disposal according to the present invention includes the following steps:

[0020] Organic solid waste enters the drying system and exchanges heat with the high-temperature flue gas sent from the combustion system, thus drying the organic solid waste.

[0021] The dried material is conveyed into the gasification and melting system through a sealed feeding system for gasification and melting. The resulting liquid slag is then transported into the gasification and melting system as a gasifying agent by the water vapor generated during the slag water quenching process. This process utilizes heat while increasing the calorific value of the crude syngas.

[0022] The crude syngas generated in the gasification and melting system is drawn out by the blower and enters the combustion system for complete combustion. At the end of the combustion system, it is mixed with the circulating air from the drying system to obtain high-temperature flue gas at the target temperature, which is then used as a heat source to enter the drying system.

[0023] The liquid slag obtained from the gasification and melting system for treating organic solid waste can achieve the separation of heavy metals from solid slag; the high-pressure water in the water quenching system breaks up and rapidly cools the slag, and the rapid cooling and shrinkage of the slag causes stress concentration, which pulverizes it into small particles, enabling resource utilization; part of the water vapor obtained from high-pressure water washing enters the gasification and melting system as a gasifying agent, part exchanges heat with air to obtain hot air, and is used as the primary air of the combustion system, and the excess part is returned to the water quenching system after cooling, realizing the efficient utilization of heat and the recycling of water.

[0024] Furthermore, the organic solid waste enters the drying system and is transported from the kiln head to the kiln tail under the action of the frequency conversion / reverse drive device. It exchanges heat with the high-temperature flue gas sent by the combustion system and is dried to a specified moisture content range to ensure the uniformity of moisture content of materials with different properties.

[0025] Furthermore, the liquid slag obtained from the treatment of organic solid waste in the gasification and melting system achieves the separation of heavy metals from solid slag at the bottom of the gasification and melting furnace.

[0026] Furthermore, the inlet temperature of the annular high-temperature flue gas in the drying system is 600-800℃; the outlet temperature of the annular flue gas after heat exchange is 350-550℃; the temperature of the mixed flue gas containing water vapor exiting the inner cylinder is 100-150℃; and the flow rate of the high-temperature flue gas is adjusted according to the actual dehydration requirements of the material.

[0027] Furthermore, the moisture content of the raw materials entering the rotary dryer is 80%-40%; the organic solid waste is dried in the rotary dryer to reduce its moisture content to below 15%; the moisture content of the raw materials exiting the rotary dryer is below 15%, ensuring that the heat consumption of the material is relatively stable after entering the gasification melting furnace, and ensuring the stable operation of the gasification melting furnace; the processing time can be adjusted according to the degree of drying of the material, preferably 30-120 minutes.

[0028] The organic solid waste can be one or more of the following: domestic waste, sewage sludge, medical waste, and organic hazardous waste.

[0029] Furthermore, the gasification melting furnace is a vertical melting furnace; the temperature of the pyrolysis section is 200-600℃; the temperature of the gasification section is 600-1200℃; the temperature of the melting section is 1200-1700℃; the processing time is 60-120 min; the auxiliary fuel is coke and quicklime as a flux; the gasification agent is water vapor generated during the slag water quenching process; the oxygen content in the oxygen-enriched air is 30-40%; and the outlet temperature of the crude syngas is 250-400℃.

[0030] Furthermore, the fuel for the independent burner is natural gas; the amount of natural gas used can be adjusted according to system requirements; the main components of the crude syngas are at least one of CO, H2, water vapor, CO2, or CH4; the high-temperature flue gas outlet temperature is 600-800℃; the circulating air temperature is 350-550℃; and the combustion temperature of the crude syngas in the combustion furnace is 1100-1300℃.

[0031] Furthermore, the ratio of high-pressure water to molten slag is 8:1-10:1; and the temperature of the primary air after heat exchange is 150-250℃.

[0032] Beneficial effects: Compared with the prior art, the present invention achieves the following significant effects:

[0033] (1) The present invention utilizes the water quenching device of the slag discharge system to generate water quenching steam from the liquid slag produced by the gasification and melting system through high-pressure water impact. Part of the water quenching steam is used as the gasifying agent of the gasification and melting system. An appropriate amount of water quenching steam enters the gasification section of the gasification and melting furnace, which can significantly improve the gasification efficiency of fixed carbon, increase the hydrogen content in crude syngas, and further increase the added value of crude syngas. The other part is used to exchange heat with air in the heat exchange system to output hot air as the primary air of the combustion system, realizing the utilization of waste heat and improving the thermal efficiency of the system.

[0034] (2) The water quenching device can realize the adjustable and controllable output of water quenching steam, and realize the recycling of water while utilizing the waste heat of water steam;

[0035] (3) Under the reducing atmosphere and ultra-high temperature conditions in the gasification melting furnace, organic solid waste achieves complete decomposition of organic matter, dioxins, etc., as well as complete separation of heavy metals and liquid slag; the high-value-added crude syngas generated is fully combusted in the combustion system and then the waste heat is utilized; the heavy metal-free solid slag can be reprocessed through multiple pathways for resource utilization, fundamentally realizing the "four-fold" treatment of organic solid waste.

[0036] (4) The drying system of the present invention achieves adjustable and controllable drying time and degree of drying of materials in the dryer by means of heating method of rotary dryer, internal spiral baffle, frequency conversion of furnace body drive device, reverse operation and discharge temperature control, ensuring the uniformity of humidity of materials with different properties and improving the running stability of materials in gasification melting furnace.

[0037] (5) By setting up a vertical sealed feeding system, the present invention separates the drying of organic solid waste from the pyrolysis gasification and melting, allowing water vapor to escape at low temperature, while the dried material directly enters the gasification and melting furnace. This simplifies the process system and achieves the separation of water vapor and crude syngas, avoiding energy consumption of water vapor at high temperature and increasing the calorific value of crude syngas, thus achieving cost reduction and efficiency improvement in both directions. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of the system structure of the present invention;

[0039] Figure 2 This is a schematic diagram of the sealed feeding system of the present invention;

[0040] Figure 3 This is a schematic diagram of the process flow of the present invention. Detailed Implementation

[0041] The present invention will now be described in further detail with reference to the accompanying drawings.

[0042] like Figure 1 The system for improving the thermal efficiency of organic solid waste treatment according to the present invention includes a drying system 1, a sealed feeding system 2, a gasification and melting system 3, a combustion system 4, and a slag discharge system 5. The sealed feeding system 2 is connected between the discharge port 132 of the drying system and the inlet 311 of the gasification and melting system. The high-temperature flue gas inlet 124 of the drying system 1 is connected to the high-temperature flue gas outlet 45 of the combustion system 4, and the flue gas outlet 125 after heat exchange is connected to the circulating air inlet 44 of the combustion system 4; the crude syngas outlet 313 of the gasification and melting system 3 is connected to the crude syngas inlet 41 of the combustion system 4; the slag discharge system 5 includes a water quenching system 5-1 that can provide high-pressure water and a heat exchange system 5-2; the liquid slag inlet 511 of the water quenching system 5-1 is connected to the liquid slag outlet 322 of the gasification and melting system 3, and is used to rapidly cool and heat exchange the liquid slag with high-pressure water from the water quenching system 5-1 to generate water vapor; the water vapor outlet 517 of the water quenching system 5-1 has two outlets, one of which is connected to the gasifying agent inlet 312 of the gasification and melting system 3, and the other is connected to the heat exchange system 5-2; the heat exchange system 5-2 is connected to the primary air inlet 43 of the combustion system 4, and is used to send the primary hot air generated after heat exchange between air and water vapor into the combustion system 4.

[0043] The drying system 1 of the present invention includes a rotary dryer 1-1, which includes a kiln head 11, a kiln body 12, and a kiln tail 13. The kiln head 11 is provided with a raw material inlet 111 connected to a screw feeder 113 and a kiln head flue gas inlet 112. The kiln body 12 includes an outer cylinder 121, an inner cylinder 122, and a ring system 123 formed by the outer cylinder 121 and the inner cylinder 122. The kiln tail 13 is provided with an evaporation water outlet 131, a drying system outlet 132, and a material temperature tester 133. The outer cylinder 121 is provided with a high-temperature flue gas inlet 124 and a heat-exchange flue gas outlet 125. The kiln head flue gas inlet 112 is connected to the heat-exchange flue gas outlet 125. The rotary dryer 1-1 adopts a combination of indirect and direct heating of high-temperature flue gas, which can avoid the local pyrolysis of organic solid waste caused by excessively high flue gas temperature, and can make full use of flue gas heat, thereby improving drying efficiency and reducing the difficulty of tail gas treatment. The drive device of the rotary dryer 1-1 of the present invention has frequency conversion and reverse rotation functions. The rotation speed of the rotary dryer 1-1 can be adjusted according to the material temperature at the outlet, or it can be reversed to ensure that the moisture content of the material outlet is less than 15%.

[0044] like Figure 2 The sealed feeding system 2 includes a feeding pipe 21, which is located vertically below the kiln tail 13 of the rotary dryer 1-1, and is connected sequentially to the discharge port 132 of the drying system and the inlet 311 of the gasification and melting system. An upper locking valve 22 and a lower locking valve 24 are respectively located near the discharge port 132 of the drying system and the inlet 311 of the gasification and melting system on the feeding pipe 21. A locking chamber 23 is formed between the upper locking valve 22 and the lower locking valve 24. The feeding pipe 21 is equipped with an arch-breaking device 25 for rotating the material within the feeding pipe 21. The arch-breaking device 25 is connected between the upper locking valve 22 and the lower locking valve 24 via an upper flange 251 and a lower flange 252. The arch-breaking device 25 includes an arch-breaking ring 254 that fits into the feeding pipe 21, and the arch-breaking ring 254 rotates around a horizontal axis. A drive motor 253 is connected to the arch-breaking ring 254. The feeding pipe 21 is equipped with an auxiliary fuel inlet 26. The material enters the gasification and melting furnace under the rotating condition of the arch-breaking device 25, achieving sealed feeding. This ensures that the water vapor in the drying section separates and escapes from the crude syngas generated in the melting section 3-2, thereby increasing the calorific value of the crude syngas and reducing the heat demand of the melting section 3-2. After being dried by the drying system 1, the material is conveyed into the gasification and melting system 3 through the sealed feeding system 2. This prevents a large amount of water vapor from the drying system 1 from entering the gasification and melting system 3 and affecting the calorific value of the crude syngas. It also prevents a large amount of water vapor from consuming heat in the gasification and melting furnace, thus improving heat utilization.

[0045] The gasification-melting system 3 includes a gasification-melting furnace, which comprises an upper pyrolysis-gasification section 3-1 and a lower melting section 3-2. The upper part of the pyrolysis-gasification section 3-1 is the pyrolysis section, and the lower part is the gasification section. The pyrolysis-gasification section 3-1 is equipped with a gasification-melting system inlet 311, a gasifying agent inlet 312, and a crude syngas outlet 313, all connected to the feed pipe 21 of the sealed feed system 2. The melting section 3-2 is equipped with an oxygen-enriched air inlet 321, a liquid molten slag outlet 322, and a heavy metal outlet 323. The melting section 3-2 is trapezoidal in shape, reducing the melting space and increasing the thickness of the refractory material, thereby improving the heat retention capacity of the melting section 3-2 and further enhancing the system's thermal efficiency. The molten solid slag obtained from the treatment of organic solid waste in the gasification-melting furnace achieves heavy metal separation from the solid slag at the furnace bottom.

[0046] Combustion system 4 includes a combustion furnace connected to an independent burner 42. The combustion furnace is a low-NOx combustion furnace. The combustion furnace has a crude syngas inlet 41, a primary air inlet 43, a recirculating air inlet 44, and a high-temperature flue gas outlet 45. The crude syngas inlet 41 is connected to the crude syngas outlet 313 of the gasification and melting system 3. The primary air inlet 43 is connected to the hot air outlet 524 of the heat exchange system 5-2. The recirculating air inlet 44 is connected to the heat-exchanged flue gas outlet 125 of the drying system 1. The high-temperature flue gas outlet 45 is connected to the high-temperature flue gas inlet 124. The independent burner 42 and the primary air inlet 43 are symmetrically arranged vertically. The crude syngas inlet 41 is vertically arranged to both the independent burner 42 and the primary air inlet 43 to ensure complete combustion of the crude syngas. The recirculating air inlet 44 is located at the rear end of the combustion furnace; the crude syngas inlet 41 is located at the front end of the combustion furnace. The crude syngas generated in the gasification melting furnace is drawn out by a blower and directly enters the low-NOx combustion furnace. It undergoes complete combustion under the ignition of the independent burner 42. At the end of the combustion furnace, it mixes with the circulating air from the annular system 123 of the rotary dryer 1-1 to obtain high-temperature flue gas at the target temperature. This high-temperature flue gas then enters the annular system 123 of the rotary dryer 1-1 as a heat source. The combustion flue gas mixes with the circulating air at the rear end of the combustion furnace, achieving temperature control of the high-temperature flue gas exiting the furnace, thereby ensuring the heat supply to the drying system 1.

[0047] The water quenching system 5-1 in the slag discharge system 5 includes a liquid slag inlet 511, a high-pressure water jet 512, a water-slag storage tank 513, and a gas collection hood 514. The liquid slag inlet 511 is connected to the liquid slag outlet 322 of the gasification melting furnace. The high-pressure water jet 512 is located at the tail end of the chute from which the high-temperature liquid slag flows out. The high-speed water jet from the high-pressure water jet 512 breaks up and rapidly cools the slag. The rapid cooling and contraction of the slag causes stress concentration, resulting in pulverization into small particles that flow into the water-slag storage tank 513. These particles can then be retrieved for resource utilization. The high-pressure water jet 512 and the gas collection hood 514 are located above the water-slag storage tank 513. The gas collection hood 514 is used to collect the generated water vapor. Below the gas collection hood 514 are several atomizing nozzles 515 connected to the water-slag storage tank 513 via pipes. A regulating valve 516 is installed on the pipeline between the atomizing nozzle 515 and the water-slag storage tank 513. The amount of water sprayed by the atomizing nozzle 515 can be adjusted by regulating the valve 516, thereby regulating the amount of water vapor in the gas collecting hood 514. Excess water vapor is condensed and returned to the water-slag storage tank 513, and fine particles carried in the water vapor are purified. The gas collecting hood 514 has a water vapor outlet 517. One pipeline of the water vapor outlet 517 is connected to the gasifying agent inlet 312 of the gasification melting furnace, and the other pipeline is connected to the water vapor inlet 521 of the heat exchange system 5-2. The water vapor flow rates entering the gasifying agent inlet 312 and the water vapor inlet 521 are adjusted by the regulating valve based on the furnace requirements. The addition of the gasifying agent not only realizes the heat utilization of the water-quenched steam but also promotes the fixed carbon reaction, increases the hydrogen content in the crude syngas, and increases the added value of the crude syngas.

[0048] The heat exchange system 5-2 in the slag removal system 5 includes a heat exchanger, which is provided with a steam inlet 521, a condensate outlet 522, an air inlet 523 and a hot air outlet 524; the hot air outlet 524 is connected to the primary air inlet 43 of the combustion system 4; the condensate outlet 522 is connected to the water storage solid slag storage tank 513.

[0049] During the heat exchange process between high-pressure water and high-temperature molten slag, a large amount of water vapor and fine dust are generated. After the water vapor is removed by the atomizing nozzle 515, it escapes from the gas collection hood 514 under the action of the induced draft fan. Part of it enters the gasification melting furnace as a gasifying agent, and part of it enters the heat exchanger to exchange heat with the air. The hot air after heat exchange is sent into the combustion furnace as primary air to realize the utilization of waste heat and improve the thermal efficiency of the system.

[0050] Example 2

[0051] Method for gasifying and melting municipal solid waste using the system in Example 1:

[0052] The municipal solid waste, with a particle size of <10cm and a moisture content of approximately 62%, after being crushed, enters the rotary dryer 1-1 under the pushing action of the screw feeder 113. The high-temperature flue gas temperature at the inlet of the annular system 123 of the rotary dryer 1-1 is controlled at 600℃, and the outlet flue gas temperature is 280℃. Within the rotary dryer 1-1, the municipal solid waste is conveyed from the kiln head 11 to the kiln tail 13 as the kiln body 12 rotates, gradually achieving drying. The 150℃ low-temperature water vapor generated during the drying process is extracted from the kiln tail 13 by the induced draft fan, washed with water, and then sent to the exhaust gas purification system. This allows the water vapor to escape from the system at a low temperature, reducing energy consumption, and also avoids the mixing of large amounts of water with the crude syngas produced in the gasification melting furnace, thus increasing the calorific value of the crude syngas.

[0053] After drying, municipal solid waste with a moisture content of approximately 15% enters the gasification and melting furnace through a sealed feeding system 2. Simultaneously, 4 wt% of the municipal solid waste, consisting of block coke, and 8 wt% of the municipal solid waste, are also fed into the gasification and melting furnace from the bottom of the sealed feeding pipe. These components disperse within the municipal solid waste, providing space for the escape of crude syngas and supplying sufficient reducing carbon to the melting section 3-2 to maintain the system temperature and reducing atmosphere. The municipal solid waste, along with the auxiliary coke and quicklime, slowly moves downwards within the furnace, undergoing pyrolysis at 300-800℃, gasification at 800-1100℃, and melting at 1100-1500℃. During this process, the organic matter is decomposed and gasified under the action of steam, forming high-value-added crude syngas. The remaining inorganic components, dioxins, heavy metals, etc., ultimately form liquid slag under a high-temperature reducing atmosphere.

[0054] The crude syngas generated in the gasification melting furnace at 300°C escapes from the furnace under the action of a blower and enters the combustion system 4 for complete combustion at a combustion temperature of 1200°C. After being distributed with circulating air, high-temperature flue gas at 600°C is obtained. Part of the high-temperature flue gas enters the annular system 123 and inner cylinder 122 of the rotary dryer 1-1 in sequence. After drying the municipal solid waste, it enters the tail gas treatment system together with the drying water vapor and is discharged in compliance with standards. The remaining high-temperature flue gas can be used for waste heat utilization based on demand. The liquid slag discharged from the bottom of the gasification melting furnace is rapidly cooled and crushed after being washed with high-pressure water and enters the water storage solid slag storage tank 513 for later use. Part of the water vapor obtained from the high-pressure water washing enters the gasification melting furnace as a gasification agent, part exchanges heat with the air to obtain hot air, and is used as the primary air of the combustion furnace. The excess part is returned to the water storage solid slag storage tank 513 after atomization and cooling, thus realizing the efficient utilization of heat and the recycling of water.

[0055] The process flow diagram of this invention is shown below. Figure 3 As shown.

[0056] Example 3

[0057] Method for gasifying and melting industrial sludge using the system in Example 1:

[0058] Industrial sludge with a moisture content of approximately 50% after mechanical dewatering enters the rotary dryer 1-1 under the propulsion of the screw feeder 113. The inlet temperature of the high-temperature flue gas in the annular system 123 of the rotary dryer 1-1 is controlled at 650℃, and the outlet flue gas temperature is 350℃. Industrial waste is transported from the kiln head 11 to the kiln tail 13 within the rotary dryer 1-1 as the kiln body 12 rotates, gradually achieving drying. The 120℃ low-temperature water vapor generated during the drying process is extracted from the kiln tail 13 by the induced draft fan, washed with water, and then sent to the tail gas purification system. This allows the water vapor to escape from the system at a low temperature, reducing energy consumption, and also avoids mixing large amounts of water with the crude syngas produced in the gasification melting furnace, thus increasing the calorific value of the crude syngas.

[0059] After drying, industrial sludge with a moisture content of approximately 20% enters the gasification and melting furnace through a sealed feeding system 2. Simultaneously, lumpy coke (6 wt% of the industrial sludge) and quicklime (6 wt% of the industrial sludge) are also fed into the gasification and melting furnace from the bottom of the sealed feeding pipe, dispersing within the industrial sludge to provide space for the escape of crude syngas and to provide sufficient reducing carbon for the melting section 3-2, maintaining the system temperature and reducing atmosphere. The industrial sludge, auxiliary coke, and quicklime move slowly downwards within the furnace, undergoing pyrolysis at 300-800℃, gasification at 800-1100℃, and melting at 1100-1500℃. The organic matter is decomposed and gasified under the action of water vapor, forming high-value-added crude syngas (CO). The remaining inorganic components, dioxins, heavy metals, etc., ultimately form liquid slag under a high-temperature reducing atmosphere.

[0060] The 300℃ crude syngas generated in the gasification melting furnace is released by a blower and enters the combustion system 4 for complete combustion at a combustion temperature of 1100℃. After circulating air distribution, high-temperature flue gas of 650℃ is obtained. Part of the high-temperature flue gas enters the annular system 123 and inner cylinder 122 of the rotary dryer 1-1 in sequence. After the industrial sludge is dried, it enters the tail gas treatment system together with the drying water vapor and is discharged in compliance with standards. The remaining high-temperature flue gas can be used for waste heat utilization as needed. The liquid slag discharged from the bottom of the gasification melting furnace is washed with high-pressure water and then rapidly cooled and crushed. It enters the water storage solid slag storage tank 513 and is retrieved for later use. Part of the water vapor obtained from the high-pressure water washing enters the gasification melting furnace as a gasification agent, part exchanges heat with air to obtain hot air and is used as the primary air of the combustion furnace, and the excess part is returned to the water storage solid slag storage tank 513 after atomization and cooling. This achieves efficient utilization of heat and recycling of water.

Claims

1. A system for improving thermal efficiency of organic solid waste disposal, characterized by, The application relates to a dry feeding system (1), a sealed feeding system (2), a gasification melting system (3), a combustion system (4) and a slag discharging system (5); the sealed feeding system (2) is connected between a dry feeding system discharge port (132) and a gasification melting system feeding port (311); a high-temperature flue gas inlet (124) of the dry feeding system (1) is connected with a high-temperature flue gas outlet (45) of the combustion system (4), and a heat-exchanged flue gas outlet (125) is connected with a circulating air inlet (44) of the combustion system (4); a crude synthetic gas outlet (313) of the gasification melting system (3) is connected with a crude synthetic gas inlet (41) of the combustion system (4); the slag discharging system (5) comprises a water quenching system (5-1) capable of providing high-pressure water and a heat exchange system (5-2); a liquid molten slag inlet (511) of the water quenching system (5-1) is connected with a liquid molten slag outlet (322) of the gasification melting system (3), and the liquid molten slag is rapidly cooled and heat-exchanged by high-pressure water of the water quenching system (5-1) to generate water vapor; the water vapor outlet (517) of the water quenching system (5-1) is provided with two outlets, one of which is connected with a gasification agent inlet (312) of the gasification melting system (3), and the other is connected with a water vapor inlet (521) of the heat exchange system (5-2); a hot air outlet (524) of the heat exchange system (5-2) is connected with a primary air inlet (43) of the combustion system (4), and hot air generated by heat exchange of air and water vapor is sent into the combustion system (4).

2. The system for improving thermal efficiency of organic solid waste disposal according to claim 1, wherein, The gasification melting system (3) comprises a gasification melting furnace, the gasification melting furnace comprises a pyrolysis gasification section (3-1) located at an upper section and a melting section (3-2) located at a lower section; the pyrolysis gasification section (3-1) is provided with a gasification melting system feeding port (311) connected with the sealed feeding system (2), a gasification agent inlet (312) and a crude synthetic gas outlet (313); the melting section (3-2) is provided with an oxygen-enriched air inlet (321), a liquid molten slag outlet (322) and a heavy metal outlet (323).

3. The system for improving thermal efficiency of organic solid waste disposal of claim 1, wherein, The combustion system (4) comprises a combustion furnace connected with an independent burner (42); the combustion furnace is provided with a crude synthetic gas inlet (41), a primary air inlet (43), a circulating air inlet (44) and a high-temperature flue gas outlet (45); the crude synthetic gas inlet (41) is connected with the crude synthetic gas outlet (313) of the gasification melting system (3); the primary air inlet (43) is connected with the hot air outlet (524) of the heat exchange system (5-2); the circulating air inlet (44) is connected with the heat-exchanged flue gas outlet (125) of the dry feeding system (1); and the high-temperature flue gas outlet (45) is connected with the high-temperature flue gas inlet (124).

4. The system for improving thermal efficiency of organic solid waste disposal of claim 1, wherein, The water quenching system (5-1) further comprises a water storage and solid slag storage pool (513) connected with the liquid molten slag inlet (511), a high-pressure water flushing spray gun (512) located above the water storage and solid slag storage pool (513) and a gas collecting cover (514); the gas collecting cover (514) is used for collecting generated water vapor; and the water vapor outlet (517) is arranged on the gas collecting cover (514).

5. The system for improving thermal efficiency of organic solid waste disposal according to claim 4, wherein, A plurality of atomizing nozzles (515) connected with the water storage solid residue storage tank (513) by pipelines are arranged below the gas collecting hood (514).

6. The system for improving thermal efficiency of organic solid waste disposal of claim 1, wherein, The heat exchange system (5-2) is also provided with an air inlet (523) and a condensed water outlet (522), and the condensed water outlet (522) is connected with the water storage solid residue storage tank (513).

7. The system for improving thermal efficiency of organic solid waste disposal of claim 1, wherein, The drying system (1) comprises a rotary dryer (1-1), and the rotary dryer (1-1) comprises a kiln head (11), a kiln body (12) and a kiln tail (13); the kiln head (11) is provided with a raw material feeding port (111) connected with a screw feeder (113) and a kiln head flue gas inlet (112); the kiln body (12) comprises an outer cylinder (121), an inner cylinder (122) and a ring system (123) formed by the outer cylinder (121) and the inner cylinder (122); the kiln tail (13) is provided with an evaporation water outlet (131), a drying system discharge port (132) and a material temperature tester (133); the outer cylinder (121) is provided with a high-temperature flue gas inlet (124) and a heat-exchanged flue gas outlet (125); and the kiln head flue gas inlet (112) is connected with the heat-exchanged flue gas outlet (125).

8. The system for improving thermal efficiency of organic solid waste disposal of claim 1, wherein, The sealing feeding system (2) comprises a lower discharge pipe (21) sequentially connected with the drying system discharge port (132) and the gasification and melting system feeding port (311) in sequence from top to bottom, and upper and lower locking valves (22) and (24) are arranged on the lower discharge pipe (21) at positions close to the drying system discharge port (132) and the gasification and melting system feeding port (311) respectively; a locking bin (23) is formed between the upper and lower locking valves (22) and (24); the lower discharge pipe (21) is provided with an arch breaking device (25) for rotating the material in the lower discharge pipe (21), and the arch breaking device (25) is connected between the upper and lower locking valves (22) and (24) through upper and lower flanges (251) and (252) respectively; the arch breaking device (25) comprises an arch breaking ring (254) attached to the lower discharge pipe (21) and a driving motor (253) connected with the arch breaking ring (254); and the lower discharge pipe (21) is provided with an auxiliary fuel feeding port (26).

9. A method for improving thermal efficiency of organic solid waste disposal using the system of claim 1, characterized in that, The method comprises the following steps: The organic solid waste enters the drying system (1) and exchanges heat with the high-temperature flue gas sent by the combustion system (4), so that the organic solid waste is dried; The dried material is conveyed into the gasification and melting system (3) by the sealing feeding system (2) for gasification and melting, water vapor generated in the water quenching process of the obtained liquid slag in the water quenching system (5-1) is conveyed into the gasification and melting system (3) as a gasification agent, heat is utilized at the same time, and the heat value of the crude synthetic gas is improved; The crude synthetic gas generated in the gasification and melting system (3) is introduced into the combustion system (4) by a fan after being introduced out, complete combustion is carried out, and the high-temperature flue gas at a target temperature is obtained by mixing with the circulating air from the drying system (1) at the end of the combustion system (4), and the high-temperature flue gas is taken as a heat source into the drying system (1); The liquid molten slag obtained by disposing the organic solid waste in the gasification melting system (3) can realize the separation of heavy metals and solid slag; the high-pressure water of the water quenching system (5-1) can crush and rapidly cool the molten slag, the molten slag rapidly cooled and shrunk to generate stress concentration and be pulverized to form small particles, and the resource utilization can be realized; the water vapor obtained by the high-pressure water washing enters the gasification melting system (3) as a gasification agent, is heat-exchanged with air to obtain hot air, and is used as primary air of the combustion system (4), and the excess part is cooled and returned to the water quenching system (5-1), so that the efficient utilization of heat and the recycling of water are realized.

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