Internal-heating vertical anaerobic pyrolyzing furnace

Abstract

An internal heating vertical anaerobic pyrolyzing furnace comprises a closed feeding conveying auger, a grading vertical furnace bin, a deslagging bin, a fuel gas induced draft fan, a combustion chamber, a fuel gas recycling pipeline, a nitrogen circulating fan, a fuel gas heat exchanger and a gate valve, wherein the grading vertical furnace bin is sequentially divided into a pre-drying bin, an anaerobic pyrolyzing bin and a cooling bin from top to bottom through the nitrogen circulating fan and the fuel gas heat exchanger and the gate valve. One part of gas exhausted by the gas induced draft fan is conveyed to the combustion chamber, the other part of gas is conveyed to a gas inlet of the gas heat exchanger through the gas booster fan, a hot smoke exhaust end of the combustion chamber is conveyed to a hot gas inlet end of the gas heat exchanger through a pipeline, and a gas outlet of the gas heat exchanger is communicated with the anaerobic pyrolysis bin through a pipeline. The device can adapt to different materials, and the requirements for the moisture content and the granularity of the materials are low; waste heat of waste smoke can be fully utilized, gradient utilization of energy is achieved, the energy efficiency of equipment is guaranteed, the operation cost of the equipment is greatly reduced, and the competitiveness of products is improved.

Description

Technical Field

[0001] This utility model relates to the field of pyrolysis furnace technology, specifically an internally heated vertical oxygen-free pyrolysis furnace. Background Technology

[0002] In recent years, people have increasingly stringent requirements for the depth and breadth of harmless waste treatment, especially since waste in remote areas is characterized by low calorific value and diverse types. For waste treatment in remote areas, waste pyrolysis gasification technology, which has gradually emerged in recent years, has developed rapidly. Compared with incinerators of the same scale, pyrolysis gasification technology has a smaller footprint, can be made into a skid-mounted unit, and can be moved at any time, which is conducive to the treatment of decentralized waste sites. Pyrolysis gasification technology can significantly reduce local pollutant emission levels, and it also has the advantages of co-processing and energy recovery.

[0003] Existing technologies, such as invention patent CN109974006B, disclose a high-temperature pyrolysis treatment system and process for municipal solid waste, which uses conveyors, gasifiers, heat exchangers, etc., and has good results. However, the materials need to be dried, and the area occupied is large. In addition, invention patent CN111204951B discloses a skid-mounted pyrolysis treatment system for oily sludge, which uses an oily sludge spray drying system, an oily sludge vortex melting pyrolysis gasifier, an oily sludge pyrolysis gas treatment device, a burner, and a slag pool to solve the problems of large heat loss, relatively low gas yield, and incomplete pyrolysis during the pyrolysis process. However, it does not mention the oil and gas recovery and the compliance of the oily sludge after pyrolysis.

[0004] To date, all pyrolysis gasification furnaces have relatively small processing capacity. Whether they are oxygen-agnostic external heating or oxygen-deficient combustion types, the energy utilization rate is low, resulting in a generally low waste processing speed. Alternatively, the gasification furnaces may have defects such as inability to operate continuously, unstable feeding and slag discharge, and slagging. Utility Model Content

[0005] To address the aforementioned problems, the purpose of this utility model is to provide an internally heated vertical oxygen-free pyrolysis furnace.

[0006] To achieve the above objectives, the technical solution of this utility model is as follows: an internally heated vertical oxygen-free pyrolysis furnace, comprising a sealed feeding conveyor auger, a staged vertical furnace chamber, a slag discharge chamber, a gas-fired induced draft fan, a combustion chamber, a gas recirculation pipeline, a nitrogen circulation fan, and a gas heat exchanger. The staged vertical furnace chamber is equipped with multiple gate valves arranged vertically, each gate valve being driven to open and close by an external motor. The gate valves divide the staged vertical furnace chamber into a pre-drying chamber, an oxygen-free pyrolysis chamber, and a cooling chamber from top to bottom, ensuring that each chamber is independently sealed. The bottom of the cooling chamber is connected to a slag discharge chamber separated by gate valves. In the slag bin, part of the gas discharged by the gas-fired induced draft fan is sent to the combustion chamber, and another part is sent to the gas inlet of the gas heat exchanger via a gas booster fan. The hot flue gas from the combustion chamber is sent to the hot gas inlet of the gas heat exchanger via a pipeline. The other end of the gas heat exchanger is the flue gas outlet. The gas outlet of the gas heat exchanger is connected to the oxygen-free pyrolysis chamber via a pipeline. The outlet of the nitrogen circulation fan is connected to the nitrogen inlet of the cooling chamber. The nitrogen outlet of the cooling chamber is connected to the nitrogen return port of the nitrogen heat exchanger. The nitrogen outlet of the nitrogen heat exchanger is connected to the inlet of the nitrogen circulation fan.

[0007] Furthermore, a water washing and purification tower is installed at the air inlet of the gas-fired induced draft fan. The top air inlet of the water washing and purification tower is connected to the pre-drying chamber, and the bottom air outlet of the water washing and purification tower is connected to the air inlet of the gas-fired induced draft fan.

[0008] Furthermore, a gas storage tank is also provided at the outlet end of the gas induced draft fan. One outlet end of the gas storage tank is connected to the inlet end of the gas booster fan, while the other outlet end is connected to the gas inlet end of the combustion chamber.

[0009] Furthermore, the nitrogen tank is located at the outlet of the nitrogen circulation fan and is connected to the outlet of the nitrogen circulation fan.

[0010] Furthermore, an air blower is provided at the air inlet end of the nitrogen heat exchanger, and the air outlet end of the nitrogen heat exchanger is connected to the air inlet end of the combustion chamber.

[0011] Furthermore, a screw conveyor is installed at the bottom of the slag discharge bin.

[0012] Furthermore, the combustion chamber is a combustion chamber for non-condensable combustion gases at room temperature, and natural gas or diesel is used for start-up.

[0013] Furthermore, the enclosed feeding conveyor auger is equipped with a vibrating metering feeder.

[0014] Furthermore, the enclosed feeding conveyor auger is also equipped with an emergency water spray nozzle.

[0015] Furthermore, the exhaust port of the gas heat exchanger is connected to the flue gas treatment device.

[0016] This utility model uses a segmented design of a vertical furnace to allow materials to undergo a precise temperature control process inside the furnace, achieves efficient cascade utilization of energy through gas recirculation and internal heat, and realizes energy transfer through gas recovery technology.

[0017] With the above settings, this utility model has the following beneficial effects:

[0018] 1. This utility model can adapt to different materials and has relatively lenient requirements on the moisture content and particle size of the materials;

[0019] 2. The segmented design of the vertical furnace of this utility model allows the material to undergo a precise temperature control process inside the furnace, which can ensure the maximum energy utilization efficiency of each process, and the processes do not interfere with each other, so that the resulting product meets the design requirements.

[0020] 3. This utility model can make full use of the waste heat of waste flue gas, utilize energy in a cascade manner, ensure equipment energy efficiency, significantly reduce equipment operating costs, and enhance product competitiveness;

[0021] 4. This utility model achieves energy transfer through gas recovery technology, which can transform waste in areas with no high energy demand into energy suitable for transportation or transfer, so as to treat local waste in a way that suits local conditions;

[0022] 5. The gas recirculation of this utility model ensures that the obtained gas has fewer impurities and a higher calorific value, which is more conducive to further utilization;

[0023] 6. This utility model equipment has few mechanical parts, a simple structure, and is easy to operate. It is suitable for operation by personnel in rural and remote areas and for night duty, and has a high safety factor. Attached Figure Description

[0024] The present invention will now be further described with reference to the accompanying drawings.

[0025] Figure 1 This is a schematic diagram of the structure of this utility model. Detailed Implementation

[0026] like Figure 1As shown, an internally heated vertical oxygen-free pyrolysis furnace includes a sealed feeding conveyor auger 1, a staged vertical furnace silo 2, a slag discharge silo 3, a gas-fired induced draft fan 4, a combustion chamber 5, a gas recirculation pipeline 6, a nitrogen circulation fan 7, and a gas heat exchanger 8. The sealed feeding conveyor auger 1 also includes a double-door structure, a hydraulic pushing mechanism, and a gravity-feeding mechanism. The sealed feeding conveyor auger 1, as the feeding system, needs to be determined based on the material state to ensure uniform and sealed material conveying. The staged vertical furnace silo 2 is equipped with multiple vertically arranged baffles. Each slide gate valve 9 is driven by an external motor to flip and open. The slide gate valve 9 divides the graded vertical furnace chamber 2 into a pre-drying chamber 10, an oxygen-free pyrolysis chamber 11, and a cooling chamber 12 from top to bottom, and ensures that each chamber is independently sealed. That is, the furnace body is divided into different functional areas from top to bottom. The corresponding functional areas are equipped with corresponding instruments, and appropriate refractory materials and thicknesses are selected. Each functional area is separated by a flap valve or a slide gate valve. The flap valve is a grate butterfly valve structure, while the slide gate valve meets the temperature and sealing requirements of each functional area.

[0027] The bottom of the cooling chamber 12 is connected to the ash discharge chamber 3, which is separated by a gate valve 9. Part of the gas discharged by the gas-fired induced draft fan 4 is sent to the combustion chamber 5, and the other part is sent to the gas inlet of the gas heat exchanger 8 via the gas booster fan 13 and the gas recirculation pipeline 6. The hot flue gas from the combustion chamber 5 is sent to the hot gas inlet of the gas heat exchanger 8 through a pipeline. The other end of the gas heat exchanger 8 is the flue gas outlet. The combustion chamber 5 uses purified gas as fuel and performs high-temperature combustion with a fixed amount of hot air mixed in, with a combustion temperature >850°C. The temperature is ℃, the residence time in the combustion chamber exceeds 2 seconds, the burner used is a multi-stage burner with safety interlock function, the gas pipeline has safety measures such as flow indicator and check valve, the gas booster fan 13 and gas heat exchanger 8 form a gas recirculation system, using purified pyrolysis gas as heat carrier, pressurized by gas booster fan 13, and then heated to above 600℃ by indirect heat exchanger (gas heat exchanger 8), and then introduced into the oxygen-free pyrolysis chamber to heat and pyrolyze the waste. The gas heat exchanger 8 is equipped with flow metering and safety assurance devices;

[0028] The gas outlet of the gas heat exchanger 8 is connected to the oxygen-free pyrolysis chamber 11 via a pipeline. The exhaust end of the nitrogen circulating fan 7 is connected to the nitrogen inlet of the cooling chamber 12. The nitrogen outlet of the cooling chamber 12 is connected to the nitrogen return port of the nitrogen heat exchanger 14. The nitrogen outlet of the nitrogen heat exchanger 14 is connected to the inlet of the nitrogen circulating fan 7, thus forming a nitrogen cooling system. Nitrogen can be recycled. The nitrogen tank 17 is located at the outlet of the nitrogen circulating fan 7 and is connected to the outlet of the nitrogen circulating fan 7. Nitrogen lost during the process can be replenished at any time through the nitrogen tank 17. The nitrogen circulation loop is equipped with a cyclone dust collector and flow meter. The exhaust port of the gas heat exchanger 8 is connected to the flue gas treatment device for easy purification of the flue gas. One of the outlets of the gas storage tank 16 is connected to the inlet of the gas booster fan 13, and the other outlet is connected to the gas inlet of the combustion chamber 5. An air blower 18 is installed at the air inlet of the nitrogen heat exchanger 14. The air outlet of the nitrogen heat exchanger 14 is connected to the air inlet of the combustion chamber 5, so that the air entering the combustion chamber 5 is preheated, effectively improving the heat energy recovery rate.

[0029] The bottom of the slag discharge bin 3 is equipped with a screw conveyor. The combustion chamber 5 is a combustion chamber for non-condensable gas at room temperature. Natural gas or diesel is used when starting the furnace. The closed feeding conveyor auger 1 is equipped with a vibrating metering feeder and an emergency water spray nozzle. In addition, a water washing and purification tower 15 is installed at the air inlet of the gas-fired induced draft fan 4. The top air inlet of the water washing and purification tower 15 is connected to the pre-drying chamber 10, and the bottom air outlet of the water washing and purification tower 15 is connected to the air inlet of the gas-fired induced draft fan 4. A gas storage tank 16 is also installed at the air outlet of the gas-fired induced draft fan 4. After purification, the gas is placed in the gas storage tank 16 to reduce the operational instability caused by gas pressure fluctuations. There are multiple purification methods, and single-stage or multi-stage water washing and dust removal processes can be selected according to the material state.

[0030] It is also equipped with common electrical safety systems, including interlocking safety systems. In system control, all operations can be automatically controlled according to presets. Electrical components use PLC communication for integrated control and are equipped with emergency interlocking measures to ensure safety.

[0031] The working principle of this utility model is as follows: After being lifted by the feeding elevator to the closed feeding conveyor auger 1, the waste is transported by the closed feeding conveyor auger 1 to the graded vertical furnace silo 2. The material first falls into the pre-drying silo 10, which is separated from the oxygen-free pyrolysis silo 11 by a flap valve. The flap valve is in the form of a grate support to facilitate airflow. When it is flipped, the material above falls down. The pre-dried material falls into the lower oxygen-free pyrolysis silo 11, where the gas, which reaches a temperature of over 600°C after heat exchange, provides the heat source. The gas is directly pyrolyzed in contact with the waste. The resulting pyrolysis gas is purified by a water washing and purification tower 15 to remove dust and large molecular tar. The resulting non-condensable gas is stored in a gas storage tank 16. Part of the gas in the gas storage tank 16 is used as fuel and as a heat source for the system. It is burned in an oxygen-enriched combustion chamber 5. The other part of the gas is used as a heat carrier. After absorbing heat through a partition heat exchanger (gas heat exchanger 8), it is circulated back to the oxygen-free pyrolysis chamber 11 for waste pyrolysis. The flue gas after combustion is sent to the tail gas treatment device for purification before being discharged.

[0032] The residue after waste pyrolysis falls into cooling chamber 12, which is separated from oxygen-free pyrolysis chamber 11 by a slide gate valve. Nitrogen gas is used to directly contact the slag to cool it, while the nitrogen gas serves as a heat source for air preheating and can be cooled by the air. It is recycled, and the nitrogen gas lost is automatically replenished by nitrogen tank 17. The preheated air is used as combustion air to improve the combustion efficiency of the gas in combustion chamber 5. The cooled slag falls into slag discharge chamber 3, which is separated from cooling chamber 12 by a slide gate valve. The slide gate valves are opened and closed alternately from bottom to top to ensure that the oxygen-free environment inside the furnace is not affected. The cooled slag in slag discharge chamber 3 is discharged through the slide gate valve and then sent out by a screw conveyor or other conveying mechanism such as a belt conveyor to the slag storage chamber.

[0033] After cooling the slag, a nitrogen-equipped cyclone dust collector is used to remove dust from the slag. In the pyrolysis gas purification process, multi-stage water washing, cyclone dust collection, and bag filter dust collectors can be added to further increase the purity of the fuel gas.

[0034] The above description is merely an illustrative embodiment of this utility model and is not intended to limit the scope of this utility model. Any equivalent changes and modifications made by those skilled in the art without departing from the concept and principles of this utility model should fall within the protection scope of this utility model.

Claims

1. An internal heat vertical oxygen-free pyrolysis furnace, comprising a closed feed conveying screw (1), a staged vertical furnace bin (2), a slag discharge bin (3), a gas induced draft fan (4), a combustion chamber (5), a gas recirculation pipeline (6), a nitrogen circulating fan (7), and a gas heat exchanger (8), characterized in that: A plurality of flashboard valves (9) are arranged in the grading vertical furnace bin (2) in up-down arrangement, each flashboard valve (9) is driven to turn open and close by an external motor, and the grading vertical furnace bin (2) is sequentially divided into a pre-drying bin (10), an anaerobic pyrolysis bin (11) and a cooling bin (12) from top to bottom by the flashboard valves (9); The cooling bin (12) is communicated with a slag discharge bin (3) separated by a flashboard valve (9), a part of the flue gas discharged by a gas induced draft fan (4) is delivered to a combustion chamber (5), another part is delivered to a gas inlet of a gas heat exchanger (8) through a gas booster fan (13), a hot flue gas discharge end of the combustion chamber (5) is delivered to a hot gas inlet of the gas heat exchanger (8) through a pipeline, the other end of the gas heat exchanger (8) is a flue gas discharge port, and a gas outlet of the gas heat exchanger (8) is communicated with the anaerobic pyrolysis bin (11) through a pipeline, a nitrogen gas circulating fan (7) is communicated with a nitrogen gas inlet of the cooling bin (12), and a nitrogen gas outlet of the cooling bin (12) is communicated with a nitrogen gas backflow port of a nitrogen gas heat exchanger (14), and a nitrogen gas discharge port of the nitrogen gas heat exchanger (14) is communicated with an air inlet of the nitrogen gas circulating fan (7).

2. A vertical, internally heated, oxygen free pyrolysis furnace as claimed in claim 1, characterized in that: A water washing and purifying tower (15) is arranged at the air inlet of the gas induced draft fan (4), a top air inlet of the water washing and purifying tower (15) is communicated with the pre-drying bin (10), and a bottom air outlet of the water washing and purifying tower (15) is communicated with the air inlet of the gas induced draft fan (4).

3. An internal-heating vertical non-oxygen pyrolysis furnace according to claim 1, characterized in that: A gas storage tank (16) is further arranged at the air outlet of the gas induced draft fan (4), one air outlet of the gas storage tank (16) is communicated with an air inlet of the gas booster fan (13), and the other air outlet is communicated with a gas inlet of the combustion chamber (5).

4. An internal-heating vertical non-oxygen pyrolysis furnace according to claim 1, characterized in that: A nitrogen tank (17) is arranged at the air outlet of the nitrogen gas circulating fan (7) and is communicated with the air outlet of the nitrogen gas circulating fan (7).

5. An internal-heating vertical non-oxygen pyrolysis furnace according to claim 1, characterized in that: An air blower (18) is arranged at an air inlet of the nitrogen gas heat exchanger (14), and an air outlet of the nitrogen gas heat exchanger (14) is communicated with an air inlet of the combustion chamber (5).

6. An internal-heating vertical non-oxygen pyrolysis furnace according to claim 1, characterized in that: A screw conveying device is arranged at the bottom of the slag discharge bin (3).

7. A vertical, internally heated, oxygen free pyrolysis furnace as claimed in claim 1, wherein: The combustion chamber (5) is a combustion chamber for normal-temperature non-condensable gas, and natural gas or diesel oil is used when the furnace is started.

8. A vertical, internally heated, oxygen free pyrolysis furnace as claimed in claim 1, wherein: The closed material conveying auger (1) is provided with a shock metering feeder.

9. A vertical, internally heated, oxygen free pyrolysis furnace as claimed in claim 1, wherein: The closed material conveying auger (1) is further provided with an emergency water spray faucet.

10. A vertical, internally heated, oxygen free pyrolysis furnace as claimed in claim 1, wherein: The flue gas discharge port of the gas heat exchanger (8) is communicated with a flue gas treatment device.

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