A waste-derived fuel thermal decomposition system and thermal decomposition process

Abstract

The present invention relates to the technical field of waste recycling, and in particular to a waste-derived fuel thermal decomposition system and a thermal decomposition process method. The thermal decomposition system comprises a pyrolysis furnace, a hot air generation system, a wet spray dust removal tower, an indirect water cooling collection device, an oil-water separation system, a circulating water cooling tower, and a water seal tank. The non-condensable gas in the pyrolysis gas is introduced into the hot air generation system through the water seal tank, and serves as the combustion energy of the hot air generation system, thereby reducing the use of external energy. The present invention adopts an airtight material conveying mechanism to convey and discharge the materials in the pyrolysis furnace, and realizes the isolation of the air during the material entering the pyrolysis furnace and the slag discharge process, thereby avoiding the explosion caused by the combustion of the pyrolysis gas, so that the pyrolysis furnace can operate continuously, and avoids the use of an intermittent pyrolysis furnace to open the furnace door each time. The furnace door will have a large amount of VOC and dust unorganized emission during the slag discharge process, and at the same time avoids the waste of energy caused by the need to re-heat the pyrolysis furnace each time the intermittent pyrolysis furnace is opened, thereby improving the production capacity of resource utilization.

Description

Technical Field

[0001] The invention relates to the technical field of garbage recycling, and in particular to a garbage-derived fuel thermal decomposition system and a thermal decomposition process method. Background Art

[0002] Solid waste, including raw garbage, is the main source of soil, water and air pollution. Environmental governance should start with reducing the amount of solid waste and reducing pollutant emissions during the disposal process. In terms of composition, solid waste is a mixture of inorganic and organic matter. Among them, inorganic matter is divided into metals and non-metals; organic matter is usually divided into easily decomposable organic matter and difficult to decompose organic matter according to its short-term corruption characteristics. After removing inorganic matter and easily decomposable organic matter, solid waste is mainly composed of plastics, fabrics, rubber, bamboo, wood, paper, etc., which is called refuse-derived fuel (also called RDF), which is the fourth generation of green energy products after coal, oil and natural gas. Since the birth of the RDF concept in the middle of the last century, people have been exploring the resource utilization technology of RDF. So far, there is no recognized environmentally friendly, efficient and versatile process method.

[0003] Due to the chlorine content in the components, in order to reduce and inhibit dioxins, initially in Europe and the United States, RDF was used by coal-fired power plants. There was also a practice of removing chlorine-containing components at the source to prepare "clean" RDF. Recently, some people have studied the pyrolysis and gasification combustion technology of RDF. All explorations are aimed at maximizing the energy or resource utilization of RDF while reducing or eliminating the pollutant emissions generated in the resource utilization process, especially the emission of dioxins.

[0004] Although coal-fired fuel can solve some pollution emission problems, it also places high demands on RDF products, otherwise the boiler system must be modified. RDF is a low-value resource. Deep processing and long-distance transportation will offset its own resource output value. Coal-fired fuel can only be used under certain conditions and cannot be promoted. Eliminating chlorine-containing components at the source is a practice that is not worth the cost and has been basically eliminated due to its low commercial value.

[0005] The so-called pyrolysis gasification is actually to first partially burn RDF in the first combustion chamber under the condition of controlling the oxygen concentration to generate flue gas containing combustible gas, and then the flue gas is burned at a high temperature in the second combustion chamber for the second time, and the high temperature of the secondary combustion is used to increase the incineration rate of organic matter and reduce the generation of dioxins. In fact, it is still a kind of incineration process. The emission of pollutants such as dust, sulfur oxides, nitrogen oxides, and dioxins cannot be eliminated, but the emission is reduced a little. Therefore, it has not been fully accepted by the industry and the public so far.

[0006] The real RDF thermal decomposition should be to heat the organic matter to above the decomposition temperature by indirect heating under air-tight conditions, so that the molecular bonds of the organic matter in the RDF are broken, and the gaseous small-molecule organic matter is formed, which forms pyrolysis gas with the evaporated and generated water molecules; the inorganic matter (ash) mixed with the RDF and the fixed carbon form carbon slag. After the pyrolysis gas is condensed and collected, a pyrolysis liquid and a combustible gas that does not condense at room temperature are obtained; the pyrolysis liquid is composed of high-boiling-point organic matter and water, and after oil-water separation, a pyrolysis oil that is convenient to store, transport and use can be obtained. The high-temperature flue gas generated by the high-temperature combustion of the non-condensable combustible gas at room temperature in a special combustion chamber is used to heat the pyrolysis reactor. The non-condensable gas does not need to be stored or wasted, and the entire pyrolysis does not require additional heat energy.

[0007] Pyrolysis does not require high morphology of RDF, and does not require molding, excessive refining and drying. It consumes only 15%-20% of the energy of RDF itself to achieve full resource conversion, and 80%-85% of the energy is retained. Compared with incineration, what is burned is the purified small molecule non-condensable gas that only accounts for 15%-20% of the organic components of RDF. The concentration of pollutants such as flue gas emissions, dust, sulfur oxides, and nitrogen oxides are greatly reduced. It is an emission-reducing, environmentally friendly, and efficient RDF resource disposal technology.

[0008] So, how to ensure that the air is isolated during the RDF pyrolysis process to ensure the long-term, safe and stable operation of the system; how to safely and efficiently recycle the various components in the pyrolysis gas to avoid shutdowns and accidents caused by pipeline and tower blockages; how to increase the production capacity of the pyrolysis furnace to meet the needs of large-scale industrial production; and how to improve the degree of automation of the pyrolysis system; etc. have become issues that need to be urgently resolved. Summary of the invention

[0009] In order to overcome the defects of the prior art, the present invention provides a garbage-derived fuel thermal decomposition system and a thermal decomposition process method, which can realize continuous air-isolated feeding and slag discharge, and achieve long-term stable operation of the pyrolysis system; reasonably and efficiently recover and utilize pyrolysis products, and reduce the energy consumption of the pyrolysis process, while maximizing the production capacity of a single pyrolysis equipment, increasing the yield of garbage treatment products, and improving economic benefits; minimizing the emission of waste gas and wastewater in the pyrolysis process, and realizing low-emission disposal of garbage.

[0010] In order to achieve the above purpose, the present invention adopts the following technical solution:

[0011] A waste-derived fuel thermal decomposition system comprises a hot air generating system, a pyrolysis furnace, a wet spray dust removal tower, an indirect water cooling collection device, a jacketed cooling pipe, an oil-water separation system, a dust removal tower spray water circulation system, and a circulating water cooling tower. The pyrolysis furnace comprises an inner cylinder for containing materials to be pyrolyzed, an outer cylinder is arranged outside the inner cylinder, an annular channel for heating flue gas to enter is formed between the outer cylinder and the inner cylinder, and the annular channel is connected to the hot air outlet of the hot air generating system; a material inlet is arranged at the front end of the pyrolysis furnace, a slag discharge port and a pyrolysis gas outlet are arranged at the rear end, and a material conveyor with a sealing function is arranged at the material inlet and the slag discharge port; a pyrolysis gas outlet of the pyrolysis furnace It is connected with the air inlet of the wet spray dust removal tower, and the air outlet of the wet spray dust removal tower is connected with the inlet of the material to be cooled of the indirect water cooling collection device; the outlet of the cooled material of the indirect water cooling collection device is connected with the inlet of the material to be cooled of the jacketed cooling pipe, and the material outlet of the jacketed cooling pipe is connected with the oil-water buffer tank, and the oil-water buffer tank is provided with a gas outlet and a liquid phase outlet, and the gas outlet is connected with the water seal tank, and the gas outlet of the water seal tank is connected with the non-condensable gas burner of the hot air generating system, and the liquid phase outlet is connected with the oil-water separation system; the oil-water separation system is provided with a pyrolysis oil discharge port and a pyrolysis water discharge port, and the pyrolysis water discharge port is connected with the spray water circulation system of the dust removal tower;

[0012] It also includes a carbon slag cooling system for cooling the discharged carbon slag, the cooling water outlet of the circulating water cooling tower is connected to the cooling medium inlet of the jacketed cooling pipe, the cooling medium outlet of the jacketed cooling pipe is connected to the cooling medium inlet of the indirect water cooling collection device, the cooling medium outlet of the indirect water cooling collection device is connected to the cooling medium inlet of the carbon slag cooling system, and the cooling medium outlet of the carbon slag cooling system is connected to the circulating water cooling tower.

[0013] Optionally, the pyrolysis furnace also includes a driving mechanism for driving the inner cylinder to rotate, and furnace covers for sealing the pyrolysis furnace are also provided at both ends of the pyrolysis furnace, and the furnace cover and the inner cylinder of the pyrolysis furnace are connected by a high-temperature dynamic sealing component; a high-temperature flue gas dynamic sealing structure is arranged between the outer cylinder and the inner cylinder at the end of the pyrolysis furnace; the material inlet of the pyrolysis furnace is arranged on the front end furnace cover, and the slag discharge port and the pyrolysis gas outlet are arranged on the rear end furnace cover; and the inner wall of the outer cylinder of the pyrolysis furnace is paved with insulation material.

[0014] Optionally, a cold air distribution device is provided at the hot air outlet of the hot air generating system, and the cold air distribution device includes a cold air pipe connected to the hot air outlet, and a regulating valve for adjusting the cold air volume is provided at the outlet of the cold air pipe. The cold air introduced through the cold air pipe is mixed with the hot air discharged from the hot air outlet to adjust the temperature of the hot air entering the pyrolysis furnace.

[0015] In the present invention, the hot air generation system is separately provided, and the pyrolysis gas which cannot be condensed at room temperature is used as fuel, and the combustion temperature is not lower than 1000°C. A regulating valve for adjusting the air volume is provided at the hot air outlet, and secondary air distribution is performed to adjust and control the hot air temperature for heating the pyrolysis furnace between 800°C and 900°C. The hot air after adjusting the temperature enters between the inner and outer cylinders from the slag discharge end of the pyrolysis furnace, and is discharged from the flue gas outlet at the feed end of the pyrolysis furnace after heating the pyrolysis furnace. The flue gas is discharged in compliance with the standards after waste heat recovery and purification.

[0016] The working process of the thermal decomposition system of the present invention is as follows:

[0017] 1. After the pyrolysis gas is discharged from the pyrolysis furnace, it enters the wet spray dust removal tower. The wet spray dust removal tower uses the pyrolysis water after oil-water separation as the spray medium to spray and wash the pyrolysis gas discharged from the pyrolysis furnace to remove the carbon slag particles and high molecular weight tar components carried therein, so as to achieve the purpose of purifying the pyrolysis gas;

[0018] 2. The material outlet of the wet spray dust removal tower is connected to the inlet of the indirect water cooling collection device. The indirect water cooling collection device is an indirect cooling heat exchanger that uses the cooling water of the circulating water cooling tower as the cooling medium. Multiple indirect cooling heat exchangers can be connected in series. The pyrolysis gas enters from the top. After being cooled, some high-boiling point components are liquefied into pyrolysis liquid. The components that cannot be condensed and the components that have not had time to condense are still gases. The two flow out from the bottom of the indirect cooling heat exchanger together and enter the jacketed cooling pipe;

[0019] 3. The cooling pipe of the jacket is a pyrolysis gas / liquid mixture channel. Cold water is passed into the external jacket to deeply cool the pyrolysis gas / liquid mixture, and the condensable components of the pyrolysis gas that have not been liquefied in time collected by the indirect water cooling and collection device at the previous level are liquefied and collected;

[0020] 4. The non-condensable gas discharged from the oil-water buffer tank is recycled to the hot air generation system for use as fuel, reducing the cost of additional energy. The pyrolysis liquid discharged from the oil-water buffer tank is separated into pyrolysis oil and pyrolysis water after oil and water separation. The pyrolysis water is recycled as spray water for the wet spray dust removal tower, making full use of resources and improving production capacity.

[0021] 5. The cooling medium of the circulating water cooling tower, jacketed cooling pipe, indirect water cooling collection device and carbon slag cooling system forms a closed loop, which reduces costs and improves the stability and production capacity of the system operation.

[0022] Optionally, the thermal decomposition system further comprises a circulating water pump for providing power for water circulation among the circulating water cooling tower, the jacketed cooling pipe, the indirect water cooling collection device and the carbon slag cooling system.

[0023] Optionally, the thermal decomposition system further comprises a spray flushing system for flushing the indirect water cooling collection device.

[0024] Optionally, the spray flushing system of the indirect water cooling collection device is connected to the drain outlet of the oil-water separation system.

[0025] The waste-derived fuel thermal decomposition system of the present invention passes the pyrolysis gas that cannot be condensed after cooling and collection through a water seal tank for purification and then is introduced into a hot air generating system as the combustion energy of the hot air generating system, thereby reducing the use of external energy and improving the RDF resource utilization rate. The provision of the water seal tank can prevent the non-condensable gas combustion chamber from backfiring, while purifying the non-condensable gas and further purifying the flue gas.

[0026] In addition, the present invention uses the pyrolysis water separated by the oil-water separation system as the purification medium, purifies the pyrolysis gas by spraying in the dust removal tower, removes the dust and high molecular weight tar entrained in the pyrolysis gas, and can effectively prevent the pipes and towers of the pyrolysis liquid collection system from being blocked, thereby ensuring the system's working efficiency and long-term stable operation.

[0027] In the above-mentioned thermal decomposition system, sealing mechanisms and micro-negative pressure operating mechanisms are provided at both ends of the pyrolysis furnace to realize the pneumatic sealing of the inner cylinder pyrolysis, prevent the leakage of combustible gas, and ensure the safe and stable operation of the system. A high-temperature flue gas dynamic seal is provided between the inner cylinder and the outer cylinder to prevent the leakage of high-temperature flue gas and reduce the energy consumption of the pyrolysis process.

[0028] In order to avoid the factors that affect efficiency, increase consumption and emissions, such as heating, cooling, stopping, feeding and discharging, etc. during each pyrolysis process of the intermittent pyrolysis furnace, the pyrolysis system of the present invention adopts a conveyor with a sealing function for material transportation and slag removal, which is a necessary guarantee for realizing continuous production of the pyrolysis system and improving pyrolysis capacity.

[0029] A process for thermal decomposition of waste-derived fuel using the thermal decomposition system comprises the following steps:

[0030] 1) Close the material inlet and slag outlet of the pyrolysis furnace, turn on the natural gas burner of the hot air generation system, use natural gas as fuel to produce hot air, adjust the air volume to control the hot air temperature entering the inner and outer tube channels of the pyrolysis furnace to be between 800℃ and 900℃, and rotate the inner tube of the pyrolysis furnace to preheat the pyrolysis furnace;

[0031] 2) When the temperature of the pyrolysis furnace rises to above 380°C, start the conveyor with sealing function to continuously convey materials into the pyrolysis furnace, open the slag outlet and the conveyor with sealing function, wet spray dust removal tower, dust removal tower spray water circulation system, and circulating water cooling tower installed at the slag outlet, and start pyrolysis production; the pyrolysis gas enters the wet spray dust removal tower for spray dust removal, and the clean pyrolysis gas after dust removal enters the indirect water cooling collection device. After preliminary cooling, the non-condensable gas and the condensed pyrolysis liquid are discharged at the same time into the jacketed cooling pipe for further cooling. The cooled non-condensable gas and pyrolysis liquid are discharged into the oil-water buffer tank, and the non-condensable gas is discharged from the gas outlet of the oil-water buffer tank and enters the non-condensable gas burner of the hot air generation system as a combustion energy source. The pyrolysis liquid is discharged from the liquid phase outlet of the oil-water buffer tank and enters the oil-water separation system. The separated pyrolysis oil and pyrolysis water are recycled, and the pyrolysis water returns to the dust removal tower spray water circulation system as water for spray dust removal.

[0032] After the pyrolysis system of the present invention enters a normal working state, it continuously feeds and discharges slag, and sends out excess pyrolysis water and pyrolysis oil, so as to maintain the normal operation of each system and enable the pyrolysis production to proceed stably.

[0033] The waste-derived fuel pyrolysis system of the present invention realizes continuous pyrolysis in an air-tight environment, and converts waste-derived fuel (RDF) with complex and diverse components, different forms, and fluctuating moisture into renewable resource products with stable quality, convenient storage, transportation, and deep processing, namely, pyrolysis oil (a mixture of various liquid organic substances) and pyrolysis carbon, and the recycling rate of organic substances in RDF is more than 80%. It has the following beneficial effects:

[0034] 1. Greatly reduces pollutant emissions in the process of converting RDF into resources. Compared with general solid waste incineration, only about 15% of the weight of organic matter in RDF is burned as clean non-condensable gas. The flue gas emitted when treating one ton of waste (taking domestic waste as an example) is less than 20% of that emitted by incineration, and the overall pollutant emissions are more than 90% lower than those of incineration treatment. The system does not emit solid waste with polluting properties such as fly ash and tailings. Compared with the intermittent air-isolated pyrolysis system, it reduces the VOC and dust emitted in the unorganized process of loading and slag discharge each time the furnace door is opened. At least 80% of carbon dioxide emissions are reduced in the solid waste disposal process.

[0035] 2. Greatly reduces the energy consumption of the RDF resource conversion process: on the one hand, it relies on part of its own energy to achieve conversion, and does not require external energy; on the other hand, compared with other pyrolysis methods with the same process principles, continuous production avoids the waste of a large amount of energy in the process of repeated heating and cooling; from an energy perspective, the energy retention and utilization rate of the entire process of RDF disposal by continuous pyrolysis resource conversion is higher than 90%.

[0036] 3. From the perspective of waste disposal, a resource-based equipment and system process has been innovated to achieve the resource-based disposal of organic waste that is difficult to biodegrade. This can completely solve the dilemma of garbage disposal and waste incineration and realize a closed-loop cycle of waste resource utilization.

[0037] 4. The system can operate stably for a long time, has high processing capacity and automation level, is safe and reliable, has a wide range of applications, and can process various solid, semi-solid and liquid organic wastes. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 is a schematic diagram of the overall structure of a waste-derived fuel thermal decomposition system provided by an embodiment of the present invention;

[0039] Figure 2 It is a schematic diagram of the overall structure of a material conveyor with a sealing function used in a thermal decomposition system provided in an embodiment of the present invention.

[0040] Figure 3 It is a schematic diagram of the overall structure of a material pusher box of a material conveyor with a sealing function used in a thermal decomposition system provided in an embodiment of the present invention;

[0041] Figure 4 yes Figure 3 Top view of the . DETAILED DESCRIPTION

[0042] The technical solution of the present invention is described in detail below through specific embodiments. Example

[0043] A waste-derived fuel thermal decomposition system, such as Figure 1 As shown, it includes a hot air generating system 13, a pyrolysis furnace 14, a wet spray dust removal tower 15, an indirect water cooling collection device 16, a jacketed cooling pipe 17, an oil-water buffer tank 18, an oil-water separation system 19, a dust removal tower spray water circulation system, a circulating water cooling tower 20, a water seal tank 21, and a carbon slag cooling system for cooling carbon slag;

[0044] The pyrolysis furnace 14 includes an inner cylinder and an outer cylinder arranged at intervals, and an annular channel for hot air from the hot air generating system to enter is formed between the inner cylinder and the outer cylinder; furnace covers are fixedly connected at both ends of the inner cylinder of the pyrolysis furnace 14, and the furnace cover and the inner cylinder are connected by a high-temperature dynamic sealing mechanism, and high-temperature flue gas dynamic sealing devices are also provided between the inner cylinder and the outer cylinder at both ends of the pyrolysis furnace 14; the outer cylinder of the pyrolysis furnace 14 is fixedly arranged, and the inner cylinder is rotatably assembled, and the pyrolysis furnace is also provided with a driving mechanism for driving the inner cylinder to rotate;

[0045] A material inlet is provided on the front end furnace cover of the pyrolysis furnace 14, and a slag discharge port and a pyrolysis gas outlet are provided on the rear end furnace cover; a material conveyor with a sealing function is provided at both the material inlet and the slag discharge port; the pyrolysis gas outlet of the pyrolysis furnace 14 is connected to the air inlet of the wet spray dust removal tower 15, and the air outlet of the wet spray dust removal tower 15 is connected to the inlet of the material to be cooled of the indirect water cooling collection device 16; the cooled material outlet of the indirect water cooling collection device 16 is connected to the inlet of the material to be cooled of the jacketed cooling pipe 17, and the material outlet of the jacketed cooling pipe 17 is connected to the oil-water buffer tank 18, and the oil-water buffer tank 18 is provided with a gas outlet and a liquid phase outlet, and the gas outlet is connected to the water seal tank 21, and the gas outlet of the water seal tank 21 is connected to the non-condensable gas burner of the hot air generating system 13, and the liquid phase outlet is connected to the oil-water separation system 19; the oil-water separation system 19 is provided with a pyrolysis oil discharge port and a pyrolysis water discharge port, and the pyrolysis water discharge port is connected to the dust removal tower spray water circulation system;

[0046] The cooling water outlet of the circulating water cooling tower 20 is connected to the cooling medium inlet of the jacketed cooling pipe 17, the cooling medium outlet of the jacketed cooling pipe 17 is connected to the cooling medium inlet of the indirect water cooling collection device 16, the cooling medium outlet of the indirect water cooling collection device 16 is connected to the cooling medium inlet of the carbon slag cooling system, and the cooling medium outlet of the carbon slag cooling system is connected to the circulating water cooling tower 20.

[0047] In order to improve the thermal insulation effect of the pyrolysis furnace, the thermal decomposition system of this embodiment uses thermal insulation material on the inner wall of the outer tube of the pyrolysis furnace 14. It should be explained that the laying of the thermal insulation material is selected according to the actual demand for thermal insulation effect, and the thermal insulation material may not be laid in other embodiments.

[0048] The thermal decomposition system of this embodiment further includes a circulating water pump for providing power for water circulation among the circulating water cooling tower 20, the jacketed cooling pipe 17, the indirect water cooling collection device 16 and the carbon slag cooling system.

[0049] In order to further recycle the pyrolysis water and ensure the stability of the system operation, the present embodiment also includes a spray flushing system for flushing the indirect water cooling collection device; the spray flushing system of the indirect water cooling collection device is connected to the drain outlet of the oil-water separation system.

[0050] In this embodiment, the hot air generating system 13 is separately provided, and uses the pyrolysis gas which cannot be condensed at room temperature as fuel, and the combustion temperature is not lower than 1000°C, and the flue gas is maintained at 1000°C for more than 5 seconds, so as to ensure that the organic matter is completely incinerated. A regulating valve for adjusting the air volume is provided at the hot air outlet, and secondary air distribution is performed to adjust and control the hot air temperature for heating the pyrolysis furnace between 800°C and 900°C. The hot air after adjusting the temperature enters between the inner and outer cylinders from the slag discharge end of the pyrolysis furnace, and is discharged from the flue gas outlet at the feed end of the pyrolysis furnace after heating the pyrolysis furnace. The flue gas is discharged in compliance with the standards after waste heat recovery and purification.

[0051] The working process of the thermal decomposition system of this embodiment is as follows:

[0052] 1. After the pyrolysis gas is discharged from the pyrolysis furnace 14, it enters the wet spray dust removal tower 15. The wet spray dust removal tower 15 uses the pyrolysis water after oil-water separation as the spray medium to spray and wash the pyrolysis gas discharged from the pyrolysis furnace to remove the carbon slag particles and high molecular weight tar components carried therein, thereby achieving the purpose of purifying the pyrolysis gas;

[0053] 2. The material outlet of the wet spray dust removal tower 15 is connected to the inlet of the indirect water cooling collection device 16. The indirect water cooling collection device 16 is an indirect cooling heat exchanger using the cooling water of the circulating water cooling tower as the cooling medium. It can be a plurality of indirect cooling heat exchangers connected in series, or a single indirect cooling heat exchanger. The pyrolysis gas enters from the top, and after being cooled, some high-boiling point components are liquefied into pyrolysis liquid, and the components that cannot be condensed and the components that have not had time to condense are still gases. The two flow out from the bottom of the indirect cooling heat exchanger together and enter the jacketed cooling pipe 17;

[0054] 3. The cooling pipe 17 of the jacket is a pyrolysis gas / liquid mixture channel. Cold water is passed into the outer jacket to deeply cool the pyrolysis gas / liquid mixture, and the condensable components of the pyrolysis gas that have not been liquefied in time collected by the indirect water cooling and collection device at the previous level are liquefied and collected;

[0055] 4. The non-condensable gas discharged from the oil-water buffer tank 18 is recycled to the hot air generation system for use as fuel, reducing the cost of additional energy. The pyrolysis liquid discharged from the oil-water buffer tank 18 is separated into pyrolysis oil and pyrolysis water after oil and water separation. The pyrolysis water is recycled as spray water for the wet spray dust removal tower, making full use of resources and improving production capacity.

[0056] 5. The cooling medium of the circulating water cooling tower 20, the jacketed cooling pipe 17, the indirect water cooling collection device 16 and the carbon slag cooling system forms a closed loop, which reduces costs and improves the stability and productivity of the system operation.

[0057] A process for thermal decomposition of waste-derived fuel using the thermal decomposition system of this embodiment includes the following steps:

[0058] 1) Close the material inlet and slag outlet of the pyrolysis furnace, turn on the natural gas burner of the hot air generation system, use natural gas as fuel to produce hot air, adjust the air volume to control the hot air temperature entering the inner and outer tube channels of the pyrolysis furnace to be between 800℃ and 900℃, and rotate the inner tube of the pyrolysis furnace to preheat the pyrolysis furnace;

[0059] 2) When the temperature of the pyrolysis furnace rises to above 380°C, start the conveyor with sealing function to continuously convey materials into the pyrolysis furnace, open the slag outlet and the conveyor with sealing function, wet spray dust removal tower, dust removal tower spray water circulation system, and circulating water cooling tower installed at the slag outlet, and start pyrolysis production; after the pyrolysis system enters normal working state, it continuously feeds and discharges slag, and sends out excess pyrolysis water and pyrolysis oil to maintain the normal operation of each system, so that the pyrolysis production can be carried out stably.

[0060] The density of the organic liquid mixed product after the pyrolysis liquid collected according to the process of this embodiment is separated into oil / water / slag three phases is 0.8-0.98g / cm 3 , containing various liquid organic substances such as hydrocarbons, alcohols, aldehydes, ketones, acids, esters, ethers, etc., with a calorific value of 8000 kcal / kg-10500 kcal / kg. It can be used as a raw material for the production of standard fuel oil by hydrorefining and the separation and extraction of chemical raw materials. The particle size of the pyrolysis carbon slag after cooling is 5-200 microns, the fixed carbon content is higher than 60%, and the pyrolysis is about 4000 kcal / kg. It can be used as a raw material for the production of fuel and activated carbon, carbon black and other products.

[0061] In order to avoid the factors that affect efficiency, increase consumption and emissions, such as the need to heat up, cool down, stop, feed and discharge in each pyrolysis process of the intermittent pyrolysis furnace 14, the pyrolysis system of this embodiment adopts a conveyor with a sealing function for material transportation and slag removal, which is a necessary guarantee for realizing continuous production of the pyrolysis system and improving pyrolysis capacity. The structure of the conveyor with a sealing function is as follows: Figure 2 , Figure 3 and Figure 4 As shown, it includes a pushing box 7, a pushing piston 6 is arranged in the pushing box 7, one side of the pushing piston 6 is connected to a push rod 4, one end of the push rod 4 is connected to the pushing piston 6, and the other end of the push rod 4 extends out of the side wall of the pushing box 7 and is connected to the hydraulic cylinder mechanism 2, and the other side of the pushing box 7 is a discharge port, and a baffle 12 is arranged at the discharge port, and one side of the baffle 12 is hinged to the pushing box 7; the hydraulic cylinder mechanism 2 drives the push rod 4 to drive the pushing piston 6 to reciprocate; the upper side of the pushing box 7 is provided with a feed port; a sealing end cover 5 is arranged between the push rod 4 and the side wall of the pushing box 7, and a dynamic seal between the push rod and the pushing box is realized by the sealing end cover 5, and a graphite packing is installed inside the sealing end cover 5;

[0062] With the material pushing direction as the front, an inert gas inlet 8 is provided on the rear side wall of the material pushing box 7 at the limit stroke of the material pushing piston 6 moving backward. During the reciprocating motion of the material pushing piston 6, the gas volume in the cavity of the material pushing box 7 on both sides will change. By providing the inert gas inlet 8 to connect the inert gas, the material pushing resistance caused by the change of the gas volume in the cavity of the material pushing box 7 is supplemented, and at the same time, the combustible gas is prevented from contacting with the air;

[0063] An ash discharge port 9 is also provided on the rear side wall of the push box 7 at the limit stroke of the push piston 6 moving backward; a receiving bin 11 is connected above the feed port of the push box 7, and the receiving bin 11 is sealed with the push box 7; an inspection port 10 is provided on the side wall of the push box 7 and / or the receiving bin 11 for inspecting the internal condition of the equipment, and a sealing cover for sealing the inspection port is provided on the inspection port 10;

[0064] The hydraulic cylinder mechanism 2 is a hydraulic cylinder mechanism with adjustable piston stroke;

[0065] When the above-mentioned conveyor with sealing function is used as a slag discharger, the feed port is connected to the slag discharge port, and the discharge port is connected to the subsequent process of slag discharge; when used as a material conveyor, the feed port is connected to the incoming material equipment, and the discharge port is connected to the feed port of the pyrolysis incineration gasification equipment. The material to be transported and discharged enters the push box through the feed port, and the push piston pushes the material forward to the discharge port according to the frequency set by the hydraulic cylinder mechanism. The material remains at the discharge port of the push box for a while, and the rear material pushes the front material forward. The front material overcomes the gravity of the baffle and falls from the discharge port; the section of material remaining in the push box and the push piston together realize the isolation of the pyrolysis incineration gasification equipment from the outside world, and minimizes the entry of outside air or the leakage of gas generated inside.

[0066] The embodiments of the present invention are described in detail above in conjunction with the drawings and embodiments, but the present invention is not limited to the above embodiments and can be changed or modified within the knowledge scope of ordinary technicians in the field without departing from the purpose of the present invention.

Claims

1. A waste-derived fuel thermal decomposition system, comprising a hot air generating system, a pyrolysis furnace, a wet spray dust removal tower, an indirect water cooling collection device, a jacketed cooling pipe, an oil-water separation system, a dust removal tower spray water circulation system, and a circulating water cooling tower, characterized in that: The pyrolysis furnace comprises an inner cylinder for containing materials to be pyrolyzed, an outer cylinder is arranged outside the inner cylinder, an annular channel for heating flue gas to pass is formed between the outer cylinder and the inner cylinder, and the annular channel is connected to the hot air outlet of the hot air generating system; a material inlet is arranged at the front end of the pyrolysis furnace, a slag discharge port and a pyrolysis gas outlet are arranged at the rear end, and a material conveyor with a sealing function is arranged at the material inlet and the slag discharge port; the pyrolysis gas outlet of the pyrolysis furnace is connected to the air inlet of the wet spray dust removal tower, and the air outlet of the wet spray dust removal tower is connected to the inlet of the materials to be cooled of the indirect water cooling collection device; the cooled material outlet of the indirect water cooling collection device is connected to the inlet of the materials to be cooled of the jacketed cooling pipe, and the material outlet of the jacketed cooling pipe is connected to the oil-water buffer tank, and the oil-water buffer tank is provided with a gas outlet and a liquid phase outlet, and the gas outlet is connected to the water seal tank, and the gas outlet of the water seal tank is connected to the non-condensable gas burner of the hot air generating system, and the liquid phase outlet is connected to the oil-water separation system; the oil-water separation system is provided with a pyrolysis oil discharge port and a pyrolysis water discharge port, and the pyrolysis water discharge port is connected to the dust removal tower spray water circulation system; It also includes a carbon slag cooling system for cooling the discharged carbon slag, wherein the cooling water outlet of the circulating water cooling tower is connected to the cooling medium inlet of the jacketed cooling pipe, the cooling medium outlet of the jacketed cooling pipe is connected to the cooling medium inlet of the indirect water cooling collection device, the cooling medium outlet of the indirect water cooling collection device is connected to the cooling medium inlet of the carbon slag cooling system, and the cooling medium outlet of the carbon slag cooling system is connected to the circulating water cooling tower; The material conveyor with sealing function comprises a pushing box, a pushing piston is arranged in the pushing box, and an inert gas inlet is arranged on the rear side wall of the pushing box at the limit stroke of the pushing piston moving backward with the pushing direction as the front.

2. The waste-derived fuel thermal decomposition system according to claim 1, characterized in that: The pyrolysis furnace also includes a driving mechanism for driving the inner cylinder to rotate, and furnace covers for sealing the pyrolysis furnace are also provided at both ends of the pyrolysis furnace; the material inlet of the pyrolysis furnace is arranged on the front furnace cover, and the slag discharge port and the pyrolysis gas outlet are arranged on the rear furnace cover; and the inner wall of the outer cylinder of the pyrolysis furnace is paved with insulation material.

3. The waste-derived fuel thermal decomposition system according to claim 2, characterized in that: A cold air distribution device is arranged at the hot air outlet of the hot air generating system, and the cold air distribution device comprises a cold air pipe connected to the hot air outlet, and a regulating valve for adjusting the cold air volume is arranged at the outlet of the cold air pipe.

4. The waste-derived fuel thermal decomposition system according to claim 2, characterized in that: It also includes a circulating water pump for providing power for water circulation between the circulating water cooling tower, the jacketed cooling pipe, the indirect water cooling collection device and the carbon slag cooling system.

5. The waste-derived fuel thermal decomposition system according to claim 2, characterized in that: It also includes a spray flushing system for flushing the indirect water cooling collection device, which is used for online cleaning of the indirect water cooling device.

6. The waste-derived fuel thermal decomposition system according to claim 5, characterized in that: The spray flushing system of the indirect water cooling collection device is communicated with the drain outlet of the oil-water separation system.

7. A process for thermal decomposition of refuse-derived fuel using the refuse-derived fuel thermal decomposition system according to any one of claims 2 to 6, characterized in that: The steps include: 1) Close the material inlet and slag outlet of the pyrolysis furnace, turn on the natural gas burner of the hot air generation system, use natural gas as fuel to produce hot air, adjust the air volume to control the temperature of the hot air entering the inner and outer tube channels of the pyrolysis furnace to be between 800℃ and 900℃, rotate the inner tube of the pyrolysis furnace to preheat the pyrolysis furnace; 2) When the temperature of the pyrolysis furnace rises to above 380°C, start the conveyor with a sealing function to continuously convey materials into the pyrolysis furnace, open the slag outlet and the conveyor with a sealing function, the wet spray dust removal tower, the dust removal tower spray water circulation system, and the circulating water cooling tower set at the slag outlet, and start the pyrolysis production; the pyrolysis gas enters the wet spray dust removal tower for spray dust removal, and the clean pyrolysis gas after dust removal enters the indirect water cooling collection device. After preliminary cooling, the non-condensable gas and the condensed pyrolysis liquid are discharged at the same time into the jacketed cooling pipe for further cooling, and the cooled non-condensable gas and pyrolysis liquid are discharged into the oil-water buffer tank, and the non-condensable gas is discharged from the gas outlet of the oil-water buffer tank and enters the non-condensable gas burner of the hot air generation system as a combustion energy source, and the pyrolysis liquid is discharged from the liquid phase outlet of the oil-water buffer tank and enters the oil-water separation system, and the separated pyrolysis oil and pyrolysis water are recycled, and the pyrolysis water returns to the dust removal tower spray water circulation system as water for spray dust removal.

Images