System and method for improving thermal efficiency of organic solid waste treatment

Abstract

The invention discloses a system and a method for improving thermal efficiency of organic solid waste treatment. The system comprises a drying system, a sealed feeding system, a gasifying and melting system, a combustion system and a deslagging system, the sealed feeding system is connected between the drying system and the gasifying and melting system; the drying system is connected with the combustion system; the gasification melting system is connected with the combustion system; the deslagging system comprises a water quenching system capable of providing high-pressure water and a heat exchange system; a liquid slag inlet of the water quenching system is connected with a liquid slag outlet of the gasification melting system, a water vapor outlet of the water quenching system is connected with a gasification agent inlet of the gasification melting system, and the other water vapor outlet of the water quenching system is connected with the heat exchange system; the heat exchange system is connected with the combustion system. The water quenching steam is used as a gasifying agent and exchanges heat with air through the heat exchange system to output hot air, so that the gasification efficiency of fixed carbon is remarkably improved, the hydrogen content in the crude synthesis gas is improved, the additional value of the crude synthesis gas is improved, waste heat utilization is realized, and the heat efficiency of the system is improved.

Description

Technical Field

[0001] The present invention relates to a method and system for treating organic solid waste, and in particular to a system and method for improving the thermal efficiency of organic solid waste treatment. Background Art

[0002] At present, the main methods for treating organic solid waste include landfill, incineration, physical method, chemical method, etc. However, most of the treatment processes have problems such as incomplete harmless treatment, high treatment costs, and secondary pollution to the environment.

[0003] The gasification and melting process is to partially burn organic solid waste under the condition of controlling the oxygen (air) supply to achieve gasification, generate combustible gas, and melt the fly ash and bottom slag at the same time. This technology can more efficiently recover resources and energy from organic solid waste, while meeting more stringent organic solid waste pollution emission standards, achieving the harmlessness and resource utilization of hazardous solid waste to the greatest extent, avoiding secondary pollution, and is a very promising method for organic solid waste disposal.

[0004] Patent CN105605581A discloses a vertical garbage gasification melting furnace. The garbage enters the melting furnace body from the furnace top feeding device, moves from top to bottom in the vertical furnace, and gradually dries and pyrolyzes the garbage through heat exchange with the rising high-temperature gas to generate combustible gas and ash; the ash further moves down into the combustion zone below to achieve gasification and melting of the ash. The process flow is simple, the system has good sealing performance, and the heat utilization rate is high. However, in actual projects, the moisture content and organic matter content of organic solid waste entering the furnace are unstable, and the heat required for drying and pyrolysis and the heat generated by the remaining fixed carbon cannot be controlled, resulting in unstable temperature in the melting section and unstable system operation.

[0005] Patent CN 108097703A discloses a plasma gasification and melting system for centralized treatment of solid waste. Through a heat exchanger and a waste heat recovery system, the sensible heat of the high-temperature gas generated by the system is effectively utilized, and the solid waste is dried and gasified using a grate furnace. Only the generated ash is subjected to high-temperature plasma melting treatment, avoiding the direct use of plasma to dry, pyrolyze and gasify the solid waste, effectively reducing the energy consumption of the system. However, this system uses a heat exchanger for waste heat recovery, and the tar dust contained in the crude synthesis gas is easy to clog the heat exchange equipment, resulting in low heat exchange efficiency and high failure rate; at the same time, the air directly enters the grate after heat exchange, and the temperature and flow cannot be effectively controlled according to the changes in raw materials; after gasification, the solid waste still needs to be heated by plasma to reach the melting temperature of the solid waste when entering the melting furnace, and the thermal efficiency of the system needs to be further improved.

[0006] The 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 it still has many shortcomings. For example, the system has low thermal utilization rate, high energy consumption, poor control of the gas entering the furnace and the reducing atmosphere in the furnace, etc., and the system needs to be further optimized. Summary of the invention

[0007] Purpose of the invention: The purpose of the present 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 inlet gas and the reducing atmosphere in the furnace;

[0008] The second object of the present 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 disposal described in the present invention comprises 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 feed port 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 synthesis gas outlet of the gasification and melting system is connected to the crude synthesis gas inlet of the combustion system; the slag discharge system comprises a water quenching system and a heat exchange system that can provide high-pressure water; 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 the liquid slag through the high-pressure water of the water quenching system to generate water vapor, and the water vapor outlet of the water quenching system is provided with two outlets, one of which is connected to the gasifying agent inlet of the gasification and melting system, and the other is 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 the heat exchange between air and water vapor into the combustion system.

[0010] Among them, the gasification and melting system includes a gasification and melting furnace, and the gasification and melting furnace includes a pyrolysis and gasification section located in the upper section and a melting section located in the lower 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 feed inlet connected to a sealed feeding system, a gasifying agent inlet and a crude synthesis gas outlet; the melting section is provided with an oxygen-enriched air inlet, a liquid slag outlet and a heavy metal outlet.

[0011] Among them, the combustion system includes a low-nitrogen combustion furnace connected to an independent burner; the combustion furnace is provided with a crude synthesis gas inlet, a primary air inlet, a circulating air inlet and a high-temperature flue gas outlet; the crude synthesis gas inlet is connected to the crude synthesis gas 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 flue gas outlet after heat exchange of the drying system; 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 vertically symmetrically arranged, and the raw synthesis gas inlet, the independent burner and the primary air inlet are vertically arranged.

[0013] Wherein, the circulating air inlet is arranged at the tail of the low-nitrogen combustion furnace; and the crude synthesis gas inlet is arranged at the head of the low-nitrogen combustion furnace.

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

[0015] Among them, a plurality of atomizing nozzles connected to the water solid slag storage tank through pipelines are arranged under the gas collecting hood.

[0016] Wherein, the heat exchange system is also provided with an air inlet and a condensed water outlet; the condensed water outlet is connected to a water-solid slag storage tank.

[0017] Among them, the drying system includes a rotary dryer, which includes a kiln head, a kiln body and a kiln tail; the kiln head is provided with a raw material feed port 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 composed of the outer cylinder and the inner cylinder; the kiln tail is provided with an evaporative water outlet, a drying system discharge port and a material temperature tester; the outer cylinder is provided with a high-temperature flue gas inlet and a flue gas outlet after heat exchange; the kiln head flue gas inlet is connected to the flue gas outlet after heat exchange; a spiral baffle is provided inside the inner cylinder to guide the material to be effectively advanced and increase the heating area; the flue gas outlet after heat exchange is provided with 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 waste heat utilization, it passes through the exhaust gas purification system and finally meets the emission standards.

[0018] Among them, the sealed feeding system includes a feed pipe connected with the discharge port of the drying system and the feed port of the gasification and melting system in turn from top to bottom, and an upper locking valve and a lower locking valve are provided on the feed pipe near the discharge port of the drying system and the feed port of the gasification and melting system respectively; a locking bin is formed between the upper locking valve and the lower locking valve; the feed pipe is provided with an arch breaking device for rotating the material in the feed pipe, and the arch breaking device is connected between the upper locking valve and the lower locking valve through an upper flange and a lower flange respectively; the arch breaking device includes an arch breaking ring fitted to the feed pipe, the arch breaking ring rotates with a horizontal axis as a rotation axis, and a driving motor connected to the arch breaking ring; the feed pipe is provided with an auxiliary fuel feed port. The feed pipe is placed vertically below the kiln tail of the rotary dryer.

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

[0020] The organic solid waste enters the drying system and exchanges heat with the high-temperature flue gas sent from the combustion system to dry the organic solid waste;

[0021] The dried material is transported to the gasification and melting system through a sealed feeding system for gasification and melting. The liquid slag obtained is transported to the gasification and melting system as a gasifying agent through the water quenching process of the slag in the water quenching system. The heat is utilized to increase the calorific value of the crude synthesis gas.

[0022] The raw synthesis gas generated in the gasification and melting system is drawn out by the fan 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 of the target temperature, which enters the drying system as a heat source.

[0023] The liquid slag obtained from the disposal of organic solid waste in the gasification and melting system can realize the separation of heavy metals from solid slag; the high-pressure water in the water quenching system crushes and rapidly cools the slag, and the rapid cooling and shrinkage of the slag produces stress concentration and pulverizes into small particles, which can be utilized as resources; part of the water vapor obtained by high-pressure water washing enters the gasification and melting system as a gasifying agent, and part of it is exchanged with air to obtain hot air, which is used as the primary air of the combustion system, and the excess part is returned to the water quenching system after cooling, realizing efficient utilization of heat and 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, and exchanges heat with the high-temperature flue gas sent in by the combustion system, and is dried to the specified moisture content range to ensure the moisture uniformity of materials of different properties.

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

[0026] Furthermore, the inlet temperature of the ring system high-temperature flue gas of the drying system is 600-800°C; the outlet temperature of the ring system flue gas after heat exchange is 350-550°C; the temperature of the mixed flue gas containing water vapor exiting the inner tube is 100-150°C; 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 material 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 material exiting the rotary dryer is below 15%, ensuring that the heat consumption of the material after entering the gasification and melting furnace is relatively stable, ensuring stable operation in the gasification and melting furnace; the processing time can be adjusted according to the dryness of the material, preferably 30-120 minutes.

[0028] The organic solid waste may be one or more of domestic garbage, domestic 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°C; the temperature of the gasification section is 600-1200°C; the temperature of the melting section is 1200-1700°C; the processing time is 60-120min; the auxiliary fuel is coke and the solvent quicklime; the gasifying agent is water vapor generated during the slag water quenching process; the oxygen content in the oxygen-enriched air is 30-40%; the outlet temperature of the crude synthesis gas is 250-400°C.

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

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

[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 quench the liquid slag generated by the gasification and melting system through high-pressure water impact to generate water quenching water vapor, a portion of which is used as the gasification agent of the gasification and melting system, and an appropriate amount of the water quenching water vapor 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 the crude synthesis gas, and further increase the added value of the crude synthesis gas; the other portion of the water quenching water vapor is used in the heat exchange system to exchange heat with air and output hot air as the primary air of the combustion system, thereby realizing waste heat utilization 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, while utilizing the waste heat of water steam and realizing the recycling of water;

[0035] (3) Under the reducing atmosphere and ultra-high temperature conditions in the gasification and melting furnace, the organic solid waste can be completely decomposed into organic matter, dioxins, etc., and the heavy metals and liquid slag can be completely separated. The high-value-added crude synthesis gas produced can be used as waste heat after being fully burned in the combustion system. The heavy metal-free solid slag can be reprocessed in multiple ways for resource utilization, thus fundamentally realizing the "four-in-one" disposal of organic solid waste.

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

[0037] (5) The present invention separates the drying of organic solid waste from pyrolysis, gasification and melting by setting up a vertical sealed feeding system, allowing water vapor to escape at low temperature, while the dried material directly enters the gasification and melting furnace, thereby achieving the separation of water vapor and crude synthesis gas while ensuring the simplification of the process system, avoiding the energy consumption of water vapor at high temperature, improving the calorific value of the crude synthesis gas, and achieving cost reduction and efficiency improvement in both directions. BRIEF DESCRIPTION OF THE DRAWINGS

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

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

[0040] Figure 3 It is a schematic diagram of the process flow of the present invention. DETAILED DESCRIPTION

[0041] The present invention is further described in detail below in conjunction with the accompanying drawings.

[0042] like Figure 1 The system for improving the thermal efficiency of organic solid waste treatment of the present invention comprises a drying system 1, a sealed feeding system 2, a gasification and melting system 3, a combustion system 4, and a slag removal system 5. The sealed feeding system 2 is connected between the drying system outlet 132 and the gasification and melting system feed port 311. 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 synthesis gas outlet 313 of the gasification and melting system 3 is connected to the crude synthesis gas inlet 41 of the combustion system 4; the slag discharge system 5 includes a water quenching system 5-1 and a heat exchange system 5-2 that can provide high-pressure water; 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, which is used to quickly cool the liquid slag through the high-pressure water of the water quenching system 5-1 to generate water vapor, and the water vapor outlet 517 of the water quenching system 5-1 is provided with two outlets, one outlet is connected to the gasifying agent inlet 312 of the gasification and melting system 3, and the other outlet 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, which is used to send the primary hot air generated after the heat exchange between air and water vapor into the combustion system 4.

[0043] The drying system 1 of the present invention 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 feed port 111 connected to a screw feeder 113, and a kiln head smoke inlet 112; the kiln body 12 comprises an outer cylinder 121, an inner cylinder 122 and a ring system 123 composed of 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 smoke inlet 124 and a heat-exchanged smoke outlet 125; the kiln head smoke inlet 112 is connected to the heat-exchanged smoke outlet 125. The rotary dryer 1-1 adopts a combination of indirect and direct heating of high-temperature smoke, which can not only avoid local pyrolysis of organic solid waste caused by excessively high smoke temperature, but also make full use of the heat of the smoke, improve the drying efficiency and reduce the difficulty of tail gas treatment. The driving device of the rotary dryer 1-1 of the present invention has frequency conversion and reversal functions, and can adjust the rotation speed of the rotary dryer 1-1 according to the temperature of the material at the discharge port, or perform reverse operation to ensure that the moisture content of the material at the discharge port is less than 15%.

[0044] like Figure 2 The sealed feeding system 2 includes a feed pipe 21, which is placed vertically below the kiln tail 13 of the rotary dryer 1-1, and is connected to the drying system discharge port 132 and the gasification and melting system feed port 311 in sequence from top to bottom; an upper locking valve 22 and a lower locking valve 24 are provided on the feed pipe 21, respectively, near the drying system discharge port 132 and the gasification and melting system feed port 311; a locking bin 23 is formed between the upper locking valve 22 and the lower locking valve 24; the feed pipe 21 is provided with an arch breaking device 25 for rotating the material in the feed pipe 21, and the arch breaking device 25 is connected between the upper locking valve 22 and the lower locking valve 24 through an upper flange 251 and a lower flange 252 respectively; the arch breaking device 25 includes an arch breaking ring 254 that fits the feed pipe 21, and the arch breaking ring 254 rotates with a horizontal axis as a rotation axis, and a driving motor 253 connected to the arch breaking ring 254; the feed pipe 21 is provided with an auxiliary fuel feed port 26. The material enters the gasification melting furnace under the condition of the arch breaking device 25 rotating, and sealed feeding is realized to ensure that the water vapor in the drying section and the crude synthesis gas generated by the melting section 3-2 are separated and escaped, thereby increasing the calorific value of the crude synthesis gas and reducing the heat demand of the melting section 3-2. The material dried by the drying system 1 is transported to the gasification melting system 3 through the sealed feeding system 2, thereby preventing a large amount of water vapor in the drying system 1 from entering the gasification melting system 3 to affect the calorific value of the crude synthesis gas, and also preventing a large amount of water vapor from heating up and consuming the heat in the gasification melting furnace, thereby improving the heat utilization rate.

[0045] The gasification and melting system 3 includes a gasification and melting furnace, which includes a pyrolysis and gasification section 3-1 located in the upper section and a melting section 3-2 located in the lower section; the upper part of the pyrolysis and gasification section 3-1 is a pyrolysis section, and the lower part is a gasification section; the pyrolysis and gasification section 3-1 is provided with a gasification and melting system feed port 311 connected to the feed pipe 21 of the sealed feed system 2, a gasifying agent inlet 312 and a crude synthesis gas outlet 313; the melting section 3-2 is provided with an oxygen-enriched air inlet 321, a liquid slag outlet 322 and a heavy metal outlet 323. The melting section 3-2 is in an inverted trapezoidal shape, which reduces the melting space, increases the thickness of the refractory material, improves the heat gathering capacity of the melting section 3-2, and further improves the thermal utilization rate of the system. The molten solid slag obtained by the disposal of organic solid waste in the gasification and melting furnace realizes the separation of heavy metals and solid slag at the bottom of the furnace.

[0046] The combustion system 4 includes a combustion furnace connected to an independent burner 42, and the combustion furnace is a low-nitrogen combustion furnace; the combustion furnace is provided with a crude synthesis gas inlet 41, a primary air inlet 43, a circulating air inlet 44 and a high-temperature flue gas outlet 45; the crude synthesis gas inlet 41 is connected to the crude synthesis gas 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 circulating air inlet 44 is connected to the flue gas outlet 125 after heat exchange of the drying system 1; and 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 up and down, and the crude synthesis gas inlet 41 is vertically arranged with the independent burner 42 and the primary air inlet 43, respectively, to ensure the complete combustion of the crude synthesis gas. The circulating air inlet 44 is arranged at the rear end of the combustion furnace; the crude synthesis gas inlet 41 is arranged at the front end of the combustion furnace. The crude synthesis gas generated in the gasification and melting furnace is led out by the fan and directly enters the low-nitrogen combustion furnace, where it is completely burned under the ignition of the fire source of the independent burner 42, and mixed with the circulating air in the ring system 123 of the rotary dryer 1-1 at the end of the combustion furnace to obtain high-temperature flue gas of the target temperature, which enters the ring system 123 of the rotary dryer 1-1 as a heat source. The combustion flue gas is mixed with the circulating air at the rear end of the combustion furnace to achieve temperature control of the high-temperature flue gas discharged from the furnace, thereby ensuring the heat supply of 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 spray gun 512, a water-storage solid slag storage tank 513, and a gas collecting hood 514; the liquid slag inlet 511 is connected to the liquid slag outlet 322 of the gasification melting furnace, and the high-pressure water spray gun 512 is arranged at the tail of the chute where the high-temperature liquid slag flows out. The high-speed water flow sprayed by the high-pressure water spray gun 512 crushes and rapidly cools the slag, and the slag rapidly cools and shrinks to produce stress concentration and pulverizes to form small particles, which flow into the water-storage solid slag storage tank 513 and can be fished out for resource utilization. The high-pressure water spray gun 512 and the gas collecting hood 514 are respectively located above the water-storage solid slag storage tank 513; the gas collecting hood 514 is used to collect the generated water vapor; and a plurality of atomizing nozzles 515 connected to the water-storage solid slag storage tank 513 through pipelines are arranged below the gas collecting hood 514. A regulating valve 516 is provided on the pipeline between the atomizing nozzle 515 and the water-storage solid slag storage tank 513. The regulating valve 516 is used to adjust the water spraying amount of the atomizing nozzle 515, and the amount of water vapor in the gas collecting hood 514 can be adjusted. The excess water vapor is condensed and returned to the water-storage solid slag storage tank 513, and the fine particles carried in the water vapor can be purified at the same time. A water vapor outlet 517 is provided on the gas collecting hood 514. One of the pipelines 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 entering the gasifying agent inlet 312 and the water vapor inlet 521 is adjusted by the regulating valve based on the demand in the furnace. The addition of the gasifying agent not only realizes the heat utilization of the water quenching water vapor, but also promotes the fixed carbon reaction, increases the hydrogen content in the crude synthesis gas, and increases the added value of the crude synthesis gas.

[0048] The heat exchange system 5-2 in the slag discharge system 5 includes a heat exchanger, which is provided with a water vapor inlet 521, a condensed water 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 condensed water outlet 522 is connected to the water storage solid slag storage tank 513.

[0049] A large amount of water vapor and fine dust are generated during the heat exchange process between high-pressure water and high-temperature molten slag. After the water vapor passes through the atomizing nozzle 515 for dust removal, it escapes from the air collecting hood 514 under the action of the induced draft fan. Part of the water vapor enters the gasification melting furnace as a gasifying agent, and part of the water vapor enters the heat exchanger for heat exchange with the air. The hot air after the heat exchange is sent to 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 domestic waste using the system in Example 1:

[0052] The crushed domestic garbage with a particle size of less than 10 cm and a moisture content of about 62% enters the rotary dryer 1-1 under the driving action of the screw feeder 113. The temperature of the high-temperature flue gas at the inlet of the ring system 123 of the rotary dryer 1-1 is controlled at 600°C, and the temperature of the flue gas at the outlet is 280°C. The domestic garbage is transported from the kiln head 11 to the kiln tail 13 in the rotary dryer 1-1 as the kiln body 12 rotates, and is gradually dried; the 150°C low-temperature water vapor generated during the drying process is extracted from the kiln tail 13 under the action of the induced draft fan, and is sent to the tail gas purification system after water washing, which allows the water vapor to escape from the system at a low temperature, reducing energy consumption, and at the same time avoids a large amount of water from mixing with the crude synthesis gas generated by the gasification and melting furnace, thereby increasing the calorific value of the crude synthesis gas.

[0053] After drying, the domestic waste with a moisture content of about 15% enters the gasification melting furnace through the sealed feeding system 2; at the same time, the lump coke accounting for 4wt% of the domestic waste and the quicklime accounting for 8wt% of the domestic waste are also fed into the gasification melting furnace from the bottom end of the sealed feeding pipe, dispersed in the domestic waste, providing gaps for the escape of the crude synthesis gas, and also providing sufficient reducing carbon for the melting section 3-2 to maintain the system temperature and reducing atmosphere; the domestic waste and auxiliary coke and quicklime slowly move downward in the furnace, pyrolysis at 300-800℃, gasification at 800-1100℃, and melting at 1100-1500℃, the organic matter therein is decomposed and gasified under the action of water vapor to form high-value-added crude synthesis gas; the remaining inorganic components and dioxins, heavy metals, etc. eventually form liquid slag under high-temperature reducing atmosphere;

[0054] The 300°C crude synthesis gas generated in the gasification and melting furnace escapes from the gasification and melting furnace under the action of the blower and enters the combustion system 4 and is fully burned. The combustion temperature is 1200°C. After the circulating air is matched, a high-temperature flue gas of 600°C is obtained. The high-temperature flue gas partly enters the ring system 123 and the inner cylinder 122 of the rotary dryer 1-1 in turn, and after the domestic waste is dried, it enters the exhaust gas treatment system together with the drying water vapor and is discharged in compliance with the standards; the remaining high-temperature flue gas can be used as waste heat based on demand; the liquid slag discharged from the bottom of the gasification and melting furnace is rapidly cooled and crushed after being washed with high-pressure water, and enters the water storage solid slag storage tank 513, and is fished out for use; part of the water vapor obtained by high-pressure water washing enters the gasification and melting furnace as a gasifying agent, and part of it is heat-exchanged with air to obtain hot air, which 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 cooling, thereby realizing efficient utilization of heat and recycling of water.

[0055] The process flow diagram of the present invention is as follows Figure 3 shown.

[0056] Example 3

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

[0058] The mechanically dehydrated industrial sludge with a moisture content of about 50% enters the rotary dryer 1-1 under the driving action of the screw feeder 113. The temperature of the high-temperature flue gas at the inlet of the ring system 123 of the rotary dryer 1-1 is controlled at 650°C, and the temperature of the flue gas at the outlet is 350°C. The industrial waste is transported from the kiln head 11 to the kiln tail 13 in the rotary dryer 1-1 as the kiln body 12 rotates, and is gradually dried; the 120°C low-temperature water vapor generated during the drying process is extracted from the kiln tail 13 under the action of the induced draft fan, and is sent to the tail gas purification system after water washing, which allows the water vapor to escape from the system at a low temperature, reducing energy consumption, and at the same time avoids the mixing of a large amount of water with the crude synthesis gas generated by the gasification and melting furnace, thereby increasing the calorific value of the crude synthesis gas.

[0059] After drying, the industrial sludge with a moisture content of about 20% enters the gasification melting furnace through the sealed feeding system 2; at the same time, the lump coke accounting for 6wt% of the industrial sludge and the quicklime accounting for 6wt% of the industrial sludge are also fed into the gasification melting furnace from the bottom end of the sealed feeding pipe, dispersed in the industrial sludge, providing gaps for the escape of the crude synthesis gas, and also providing sufficient reducing carbon for the melting section 3-2 to maintain the system temperature and reducing atmosphere; the industrial sludge and the auxiliary coke and quicklime slowly move downward in the furnace, pyrolysis at 300-800℃, gasification at 800-1100℃, and melting at 1100-1500℃, the organic matter therein is decomposed and gasified under the action of water vapor to form high value-added crude synthesis gas (CO); the remaining inorganic components and dioxins, heavy metals, etc. eventually form liquid slag under high-temperature reducing atmosphere;

[0060] The 300°C crude synthesis gas generated in the gasification and melting furnace escapes from the gasification and melting furnace under the action of the blower and enters the combustion system 4 and is fully burned. The combustion temperature is 1100°C. After the circulating air is matched with the air, a high-temperature flue gas of 650°C is obtained. The high-temperature flue gas partly enters the ring system 123 and the inner cylinder 122 of the rotary dryer 1-1 in turn, and enters the tail gas treatment system together with the drying water vapor after the industrial sludge is dried, and the emission meets the standards; the remaining high-temperature flue gas can be used as waste heat based on demand; the liquid slag discharged from the bottom of the gasification and melting furnace is rapidly cooled and crushed after being washed with high-pressure water, and enters the water storage solid slag storage tank 513, and is fished out for use; part of the water vapor obtained by high-pressure water washing enters the gasification and melting furnace as a gasifying agent, and part of it is heat-exchanged with air to obtain hot air, which 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 cooling, thereby realizing efficient utilization of heat and recycling of water.

Claims

1. A system for improving the thermal efficiency of organic solid waste disposal, characterized in that: The invention comprises 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 a drying system discharge port (132) and a gasification and melting system feed port (311); a high-temperature flue gas inlet (124) of the drying system (1) is connected to a high-temperature flue gas outlet (45) of the combustion system (4), and the flue gas outlet (125) after heat exchange is connected to a circulating air inlet (44) of the combustion system (4); a crude synthesis gas outlet (313) of the gasification and melting system (3) is connected to a crude synthesis gas inlet (41) of the combustion system (4); the slag discharge system (5) comprises a water quenching system (5-1) capable of providing high-pressure water and a heat exchange system (5-2). 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 quickly cool the liquid slag through the high-pressure water of the water quenching system (5-1) to generate water vapor, and the water vapor outlet (517) of the water quenching system (5-1) is provided with 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 water vapor inlet (521) of the heat exchange system (5-2); the hot air outlet (524) of 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 hot air generated after the heat exchange between air and water vapor into the combustion system (4).

2. The system for improving the thermal efficiency of organic solid waste treatment according to claim 1, characterized in that: The gasification and melting system (3) comprises a gasification and melting furnace, which comprises a pyrolysis and gasification section (3-1) located in the upper section and a melting section (3-2) located in the lower section; the pyrolysis and gasification section (3-1) is provided with a gasification and melting system feed port (311) connected to a sealed feed system (2), a gasifying agent inlet (312) and a crude synthesis gas outlet (313); the melting section (3-2) is provided with an oxygen-enriched air inlet (321), a liquid slag outlet (322) and a heavy metal outlet (323).

3. The system for improving thermal efficiency of organic solid waste treatment according to claim 1, characterized in that: The combustion system (4) comprises a combustion furnace connected to an independent burner (42); the combustion furnace is provided with a crude synthesis gas inlet (41), a primary air inlet (43), a circulating air inlet (44) and a high-temperature flue gas outlet (45); the crude synthesis gas inlet (41) is connected to the crude synthesis gas 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 circulating air inlet (44) is connected to the post-heat exchange flue gas outlet (125) of the drying system (1); and the high-temperature flue gas outlet (45) is connected to the high-temperature flue gas inlet (124).

4. The system for improving the thermal efficiency of organic solid waste treatment according to claim 1, characterized in that: The water quenching system (5-1) further comprises a water-storage solid slag storage tank (513) connected to the liquid slag inlet (511), a high-pressure water spray gun (512) located above the water-storage solid slag storage tank (513), and a gas collecting hood (514); the gas collecting hood (514) is used to collect generated water vapor; the water vapor outlet (517) is arranged on the gas collecting hood (514).

5. The system for improving thermal efficiency of organic solid waste treatment according to claim 4, characterized in that: A plurality of atomizing nozzles (515) connected to the water-solid slag storage tank (513) via pipelines are provided below the gas collecting hood (514).

6. The system for improving thermal efficiency of organic solid waste treatment according to claim 1, characterized in that: The heat exchange system (5-2) is also provided with an air inlet (523) and a condensed water outlet (522); the condensed water outlet (522) is connected to the water-solid slag storage tank (513).

7. The system for improving thermal efficiency of organic solid waste treatment according to claim 1, characterized in that: 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 feed port (111) connected to a screw feeder (113) and a kiln head smoke inlet (112); the kiln body (12) comprises an outer cylinder (121), an inner cylinder (122) and a ring system (123) composed of 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 smoke inlet (124) and a post-heat exchange smoke outlet (125); the kiln head smoke inlet (112) is connected to the post-heat exchange smoke outlet (125).

8. The system for improving thermal efficiency of organic solid waste treatment according to claim 1, characterized in that: The sealed feeding system (2) comprises a feed pipe (21) connected with the drying system discharge port (132) and the gasification melting system feed port (311) in sequence from top to bottom; an upper locking valve (22) and a lower locking valve (24) are provided on the feed pipe (21) at positions close to the drying system discharge port (132) and the gasification melting system feed port (311), respectively; a locking bin (23) is formed between the upper locking valve (22) and the lower locking valve (24); the feed pipe (21 ) is provided with an arch-breaking device (25) for causing the material to rotate in the discharge pipe (21); the arch-breaking device (25) is connected between an upper material locking valve (22) and a lower material locking valve (24) through an upper flange (251) and a lower flange (252) respectively; the arch-breaking device (25) comprises an arch-breaking ring (254) fitted with the discharge pipe (21) and a driving motor (253) connected to the arch-breaking ring (254); the discharge pipe (21) is provided with an auxiliary fuel feed port (26).

9. A method for improving the thermal efficiency of organic solid waste treatment using the system of claim 1, characterized in that: The following steps are involved: The organic solid waste enters the drying system (1) and exchanges heat with the high-temperature flue gas sent from the combustion system (4), thereby drying the organic solid waste; The dried material is transported to a gasification and melting system (3) through a sealed feeding system (2) for gasification and melting. The obtained liquid slag is transported to the gasification and melting system (3) as a gasifying agent through the slag water quenching process in a water quenching system (5-1). The heat is utilized to increase the calorific value of the crude synthesis gas. The raw synthesis gas generated in the gasification and melting system (3) is drawn out by the fan and enters the combustion system (4) for complete combustion. At the end of the combustion system (4), the raw synthesis gas is mixed with the circulating air from the drying system (1) to obtain high-temperature flue gas of the target temperature, which enters the drying system (1) as a heat source. Liquid slag obtained by treating organic solid waste in the gasification and melting system (3) can achieve separation of heavy metals from solid slag; high-pressure water in the water quenching system (5-1) crushes and rapidly cools the slag, and the slag shrinks due to rapid cooling to produce stress concentration and pulverize into small particles, which can be used as resources; part of the water vapor obtained by high-pressure water washing enters the gasification and melting system (3) as a gasifying agent, and part of it is exchanged with air to obtain hot air, which is used as primary air of the combustion system (4), and the excess part is returned to the water quenching system (5-1) after cooling, thereby achieving efficient utilization of heat and recycling of water.

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