A biomass pyrolysis coupled with direct combustion thermal carbon co-production boiler

Abstract

The present invention discloses a thermal carbon co-production boiler for biomass pyrolysis coupled with direct combustion, which includes a combustion chamber, a burnout chamber, front and rear arch triangular areas, a multi-stage spiral feeding, pyrolysis, and conveying device, and other accessories; a high-temperature flue gas indirect pyrolysis chamber is arranged in the front and rear arch triangular areas, and spiral pyrolysis devices are arranged therein. The output end can directly obtain biomass carbon or send it to the hopper after collection. In the front and rear arch pyrolysis chambers, secondary air is used to sequentially eject the pyrolyzed flue gas and the pyrolysis gas in the spiral cylinder to the upper arch area to reduce NO in the flue gas with the pyrolysis gas x by post-combustion, and the pyrolyzed flue gas is used to realize flue gas recirculation post-combustion to reduce NO x . Adjustable ventilation holes are arranged on the flat steel of the membrane water wall at the lower part of the front and rear arch pyrolysis chambers to introduce high-temperature flue gas to indirectly pyrolyze the biomass in the spiral cylinder. Fins are welded on the outside of the spiral cylinder to strengthen the heat transfer between the pyrolysis flue gas and the biomass in the spiral cylinder. Compressed air is arranged in the pyrolysis chamber to clean the ash regularly. The present invention can realize high-efficiency, low-nitrogen, and low-carbon heat supply for biomass pyrolysis coupled with direct combustion.

Description

Technical Field

[0001] The invention belongs to the technical field of energy combustion utilization, and particularly relates to a thermal carbon co-production boiler for biomass pyrolysis coupled with direct combustion. Background Art

[0002] Biomass is the fourth largest energy source after coal, oil, and natural gas. It has a large resource volume, wide distribution, is renewable, and has zero CO2 emissions during combustion, thus attracting the attention of many scholars. It mainly includes agricultural and forestry waste, domestic waste, oil plants, and so on.

[0003] The main existing technologies for the development and utilization of biomass energy include direct combustion, thermochemical conversion, and biochemical conversion. Pyrolysis is an important method for the thermochemical conversion of biomass energy. Biomass can produce biomass gas through pyrolysis gasification and biomass tar and biomass carbon through pyrolysis liquefaction. The principle of biomass pyrolysis is that biomass absorbs heat under anaerobic or low-oxygen conditions, and the organic matter in it is converted into utilizable gas, carbon, and oil. Biomass carbon formed by biomass pyrolysis has been widely used in various industries due to its high carbon content, rich plant nutrients, abundant pore structure, and large specific surface area. For example, activated carbon is used to adsorb the color, odor, and heavy metals in wastewater; it is a commonly used ideal catalyst and an electrode material for supercapacitors, and so on.

[0004] The utility model patent "An efficient biomass pyrolysis carbonization furnace" (application number: 202220504916.0) discloses an efficient biomass pyrolysis carbonization furnace. This patented technology pyrolyzes biomass by using the high-temperature flue gas formed by burning part of the pyrolysis gas to generate pyrolysis gas, thereby realizing the combustion and heat supply of its own pyrolysis gas. However, this patented technical solution has problems such as low pyrolysis efficiency and tar condensation blocking pipelines.

[0005] Through the research of scholars, the biomass pyrolysis technology has been relatively mature, but there are still problems such as tar condensation blocking equipment during transportation, high nitrogen oxide emissions, and high pyrolysis energy consumption. Therefore, the invention proposes a thermal carbon co-production boiler for biomass pyrolysis coupled with direct combustion to solve the above problems. Summary of the Invention

[0006] The purpose of the invention is to provide a thermal carbon co-production boiler for biomass pyrolysis coupled with direct combustion. By adopting a grate boiler, the efficient utilization of biomass pyrolysis gas products is realized, and problems such as equipment blockage caused by pyrolysis tar condensation are solved. The pyrolysis gas in the spiral cylinder is directly injected into the upper arch area for combustion. Since the transportation distance is short and the temperature of the transportation space is high, there is no problem of tar condensation blocking the pipeline during the transportation of pyrolysis gas.

[0007] To achieve the above object, the technical solution adopted by the present invention is as follows: A hot charcoal co-production boiler integrating biomass pyrolysis and direct combustion is a grate boiler, including a boiler body I and a grate. A front arch II and a rear arch IV are arranged between the furnace and the burnout chamber. After the membrane water walls of the front arch II and the rear arch IV are folded into the furnace, they respectively form a front arch triangular area III and a rear arch triangular area V. A spiral pyrolysis device and an ejector device are arranged in both the front arch triangular area III and the rear arch triangular area III. The ejector device connects the spiral pyrolysis device and the furnace; outside the boiler body I, a hopper, a biomass charcoal storage device, a spiral output device and a spiral conveying device are respectively arranged. The hopper is connected to the grate through a spiral feeding device. A primary air pipe is arranged below the grate; Adjustable ventilation holes are arranged in the lower part of the membrane water walls of the front arch II and the rear arch IV. The spiral pyrolysis device is arranged above the ventilation holes. The output end of the spiral pyrolysis device is connected to the biomass charcoal storage device through a carbon discharge pipe. The bottom of the biomass charcoal storage device is connected to the spiral conveying device through the spiral output device, and the spiral conveying device is connected to the hopper; The primary air and the primary flue gas enter the combustion chamber from the bottom of the grate. The secondary air enters the ejector device as a high-speed fluid and successively ejects the pyrolyzed flue gas and the pyrolysis gas in the spiral cylinder to the upper areas of the front arch II and the rear arch IV to reduce NO in the flue gas with the pyrolysis gas x and then reburn, and use the pyrolyzed flue gas to realize flue gas recirculation reburning to reduce NO x .

[0008] The spiral pyrolysis device is arranged obliquely through from the right wall to the left wall in the pyrolysis chambers of the front and rear arches. A number of pyrolysis gas ducts are evenly arranged on the spiral pyrolysis device and connected to the ejector device. The feed inlet of the spiral pyrolysis device is arranged outside the right wall and is provided with two-stage regulation at the lower part. The first pyrolysis gas duct near the feed inlet communicates with the lower part of the feed inlet. The outside of the spiral cylinder of the spiral pyrolysis device is provided with enhanced heat transfer fins, and the enhanced heat transfer fins are spiral fins, H-shaped fins or pin-shaped fins.

[0009] Each group of ejector devices is also connected to a secondary air pipe; the ejector devices are installed on the upper membrane water walls of the front arch II and the rear arch IV. A secondary air header is arranged at the top of the front arch triangular area III and the rear arch triangular area V. The secondary air pipe connects the secondary air header and the ejector device, and the outlet of the ejector device faces the outside of the top of the front arch triangular area III and the rear arch triangular area V.

[0010] The heat required for pyrolysis of biomass in the spiral pyrolysis device comes from the high-temperature flue gas introduced by the adjustable vents. Several groups of vents are arranged along the membrane water-cooled wall. Adjustment plates are welded on the vents through connecting rods. Slide blocks and channel steels superimposed on each other are welded on the adjustment plates. The slide blocks are arranged at the front end of the channel steels. The channel steels are arranged horizontally and the two sides are arranged in a semi-arc shape to be tangent to the steel pipes. Both ends of the adjustment plate extend out of the pyrolysis chamber. Adjustable screws are arranged at both ends of the adjustment plate to control the up and down movement of the adjustment plate and drive the slide blocks to move up and down. The slide blocks and channel steels can adjust the high-temperature flue gas flow rate driven by the adjustment plate. When the adjustment plate is at the lowest end, the two sides of the slide block just completely match the vents on the steel pipes and flat steels on both sides. The adjustment plate and the slide block are made of Cr25Ni20Si2 or 310 stainless steel.

[0011] A compressed air cleaning device is installed in the front arch triangle area III and the rear arch triangle area V. The compressed air cleaning device is arranged on one side of the spiral pyrolysis device. A plurality of compressed air nozzles are provided on the compressed air cleaning device. The compressed air cleaning device is horizontally arranged through the left and right walls in the front arch triangle area III and the rear arch triangle area V.

[0012] The opening surfaces of the front arch triangle area III and the rear arch triangle area V are provided with steel plates lined with refractory materials to form a closed space for the indirect pyrolysis chamber. Flange structures are provided at the upper and lower ends of the steel plates and connected to the flange structures welded on the upper and lower membrane water-cooled walls. The steel plates are regularly disassembled to clean or wash the stubborn dust deposits adhered to the spiral pyrolysis device and its accessories.

[0013] The screw conveyor runs through the hopper arranged outside the front wall, and a plurality of charcoal leakage ports are arranged at the lower part of the screw conveyor. When the biomass charcoal is not needed, the collected biomass charcoal is transferred into the hopper through the two-stage screw device, evenly distributed, and then sent to the grate to enter the furnace for combustion.

[0014] The input raw materials in the spiral pyrolysis device are dried and crushed original ecological biomass, formed biomass particles or dried urban sludge with a water content of less than about 35%.

[0015] The flue gas vents arranged on the lower membrane water-cooled walls of the front arch II and the rear arch IV are realized by removing part of the flat steel in the lower membrane water-cooled walls, and several groups of vents are arranged from right to left.

[0016] A slag-condensing tube bundle is arranged in the flue at the furnace outlet, and a high-temperature economizer and a low-temperature economizer are arranged in sequence in the flue outside the furnace.

[0017] Compared with the prior art, the biomass pyrolysis coupled direct combustion heat-coal cogeneration boiler described in the present invention has at least the following advantages:

[0018] Beneficial effects:

[0019] The present invention couples biomass pyrolysis and combustion, which can produce biomass carbon products such as activated carbon and carbon-based fertilizers. At the same time, it can reduce the utilization of fossil fuels, thereby achieving zero-carbon or even negative carbon emissions for the entire system;

[0020] The boiler described in the present invention can achieve the efficient utilization of biomass pyrolysis gas products, solve problems such as equipment blockage caused by the condensation of pyrolysis tar. The pyrolysis gas in the spiral cylinder is directly ejected to the combustion area above the arch. Since the conveying distance is short and the temperature in the conveying space is high, there is no problem of tar condensation blocking the pipeline during the transportation of pyrolysis gas. At the same time, the direct combustion of tar can fully utilize its heat;

[0021] The boiler designed in the present invention has strong fuel adaptability and can burn solid fuels such as raw biomass, formed biomass, coal, and sludge. At the same time, it can also burn the biomass carbon produced by biomass pyrolysis;

[0022] The present invention realizes the efficient utilization of the heat of the high-temperature flue gas generated by fuel combustion; vent holes are provided on the membrane water wall at the lower parts of the front and rear arches, which can be used to send the flue gas in the combustion chamber into the pyrolysis chambers of the front and rear arches to provide heat for the pyrolysis of biomass particles;

[0023] The boiler designed in the present invention has a compact structure, good economy, is convenient for operation and maintenance, and has a long service life of the equipment.

[0024] Furthermore, the feed inlet of the spiral pyrolysis device is arranged outside the right wall and is provided with two-stage regulation at the lower part. The first pyrolysis gas conduit near the feed inlet communicates with the lower part of the feed inlet, which helps to realize air staging regulation and can solve problems such as poor ventilation and incomplete combustion.

[0025] Furthermore, sliders and channel steels are welded on the adjusting plate; the channel steels are horizontally arranged and the two sides are set as semi-circular arcs tangent to the steel pipes, which can fully isolate the flame from entering the pyrolysis chambers of the front and rear arches; adjustable screws are arranged on both sides of the adjusting plate outside the pyrolysis chamber to control the up and down movement of the adjusting plate and drive the up and down movement of the sliders. The sliders and channel steels can adjust the flow rate of the high-temperature flue gas under the drive of the adjusting plate; when the adjusting plate is at the lowest end, both sides of the sliders just completely cooperate with the ventilation openings on the two sides of the steel pipes and flat steels, and can completely block the high-temperature flue gas from flowing into the pyrolysis chamber. At this time, even during operation, dynamic maintenance of unexpected pyrolysis chamber fittings can be carried out.

[0026] Furthermore, the compressed air ash cleaning device regularly removes the suspended ash particles formed during operation in real time, especially ensuring the removal of the dynamic ash accumulation on the outer shell and fins of the spiral pyrolysis device during operation.

[0027] Furthermore, flange structures are provided at the upper and lower ends of the steel plate and connected to the flange structures welded on the upper and lower membrane water-cooled walls. Regular disassembly of the steel plate can clean or wash the stubborn dust adhering to the spiral pyrolysis device and its accessories, thereby ensuring the efficiency of the spiral pyrolysis device.

[0028] Furthermore, the input raw materials of the spiral pyrolysis device are dried and crushed original ecological biomass, formed biomass particles or dried urban sludge with a moisture content of less than about 35%, and the adaptability of the boiler is better. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a schematic diagram of the structure of a biomass pyrolysis coupled direct combustion heat and carbon cogeneration boiler.

[0030] Figure 2 A top view of a biomass pyrolysis coupled direct combustion heat and charcoal cogeneration boiler.

[0031] Figure 3 for Figure 1 AA and BB cross-sections.

[0032] Figure 4 for Figure 1 Enlarged view of the mid-front arch.

[0033] Figure 5 for Figure 1 Enlarged view of the mid-rear arch.

[0034] Figure 6 In the figure, a is the front view of the H-type fin, and b is the front view of the pin-shaped fin.

[0035] Figure 7 In the figure, a is the front view of the spiral fin, and b is the side view of the spiral fin.

[0036] Figure 8 Schematic diagram of the vent structure.

[0037] Figure 9 It is a schematic diagram of the structure of the ejection device.

[0038] Numbers in the figure: 1 - hopper, 2 - ventilation hole, 3 - fin, 4 - screw pyrolysis device, 5 - compressed air soot cleaning device, 6 - pyrolysis gas conduit, 7 - secondary air duct, 8 - ejector device, 9 - steel plate, 10 - flange structure, 11 - front wall water-cooled wall, 12 - steam drum, 13 - slag screen tube bundle, 14 - high-temperature economizer, 15 - rear wall water-cooled wall, 16 - low-temperature economizer, 17 - secondary air header, 18 - compressed air nozzle, 19 - biomass charcoal storage device, 20 - screw output device, 21 - grate, 22 - ash chamber, 23 - primary air duct, 24 - screw feeding device, 25 - screw conveyor, 26 - feed inlet, 27 - adjustable screw, 28 - adjusting plate, 29 - slider, 30 - channel steel, 31 - flue gas ejection port, 32 - ejection nozzle, Ⅰ - boiler body, Ⅱ - front arch, Ⅲ - front arch triangular area, Ⅳ - rear arch, Ⅴ - rear arch triangular area. Specific embodiments

[0039] The present invention will be further described in detail below with reference to the accompanying drawings, but it is not intended to limit the present invention.

[0040] Refer to Figure 1 , the present invention provides a thermal carbon co-production boiler for biomass pyrolysis coupled with direct combustion. The boiler referred to is a grate boiler, including a boiler body Ⅰ, a grate 21, a front arch Ⅱ and a rear arch Ⅳ respectively arranged between the furnace and the burnout chamber to strengthen the furnace combustion and burnout. The lower parts of the front wall water-cooled wall 11 and the rear wall water-cooled wall 15 are respectively the membrane water-cooled walls of the front arch Ⅱ and the rear arch Ⅳ. After the membrane water-cooled walls of the front arch Ⅱ and the rear arch Ⅳ are folded into the furnace, they respectively form a front arch triangular area and a rear arch triangular area. One or several screw pyrolysis devices 4 and ejector devices 8 are respectively arranged in the front arch triangular area and the rear arch triangular area. In order to make full use of biomass charcoal, a biomass charcoal storage device 19, a screw output device 20 and a screw conveyor 25 are respectively arranged outside the boiler body; a hopper 1 is arranged outside the front wall water-cooled wall 11 and is connected to the grate 21 through a screw feeding device 24. A primary air duct 23 is arranged below the grate 21; several groups of ejector devices 8 are arranged on the upper part of the membrane water-cooled wall from the right wall to the left wall in the front arch triangular area and the rear arch triangular area, and adjustable ventilation holes 2 are arranged on the flat steel of the lower part of the membrane water-cooled wall. The screw pyrolysis device 4 is arranged above the ventilation hole 2; the output end of the screw pyrolysis device 4 is connected to the biomass charcoal storage device 19 outside the left wall through a carbon outlet pipe. A screw output device 20 is arranged at the bottom of the biomass charcoal storage device 19. The tail of the screw output device 20 is connected to the screw conveyor 25. The screw output device 20 is arranged obliquely; the compressed air soot cleaning device 5 in the front arch triangular area is arranged on the upper side of the screw pyrolysis device 4, and the compressed air soot cleaning device 5 in the rear arch triangular area is arranged on the left side of the screw pyrolysis device 4. A slag screen tube bundle 13, a high-temperature economizer 14 and a low-temperature economizer 16 are successively arranged in the flue. In the present invention, the steam drum 12 is arranged according to the prior art.

[0041] Refer toFigure 2 and Figure 3 In this embodiment, the spiral pyrolysis device 4 is disposed obliquely through the front and rear arch pyrolysis chambers from the right wall to the left wall. A number of pyrolysis gas ducts 6 are uniformly arranged on the spiral pyrolysis device 4 and communicate with the ejector device 8; the feed inlet 26 of the spiral pyrolysis device 4 is located outside the right wall, and two-stage regulation is provided below the feed inlet 26. A pipeline is provided on the pyrolysis gas duct 6 at the feed inlet to communicate with the lower part of the feed inlet 26 to prevent the pyrolysis gas in the spiral cylinder from escaping from the hopper. Reinforced heat exchange fins 3 are welded to the outside of the spiral cylinder of the spiral pyrolysis device 4. The reinforced heat exchange fins 3 can be spiral fins, H-shaped fins or pin fins, so that the biomass particles can fully obtain heat for pyrolysis. Refer to Figure 6 、 Figure 7 。

[0042] Refer to Figure 1 、 Figure 4 、 Figure 5 and Figure 9 ,A number of groups of ejector devices 8 are provided on the upper part of the membrane water wall in the front arch triangular area and the rear arch triangular area from the right wall to the left wall. In the front and rear arch pyrolysis chambers, secondary air is used to eject the pyrolyzed flue gas and the pyrolysis gas in the spiral cylinder into the upper arch area in sequence; each group of ejector devices is provided with a secondary air pipeline 7, a pyrolysis gas duct 6, a number of flue gas ejector ports 31 and ejector nozzles 32. The flue gas ejector ports 31 and the ejector nozzles 32 are arranged along the axis of the ejector device 8. The flue gas ejector ports 31 communicate with the secondary air pipeline 7, and the ejector nozzles 32 face the outside of the top surface of the pyrolysis chamber; the secondary air pipeline 7 is connected to the secondary air header 17 provided at the top of the front and rear arch pyrolysis chambers.

[0043] Refer to Figure 8 ,In this embodiment, the heat required for biomass pyrolysis in the spiral pyrolysis device 4 provided in the front and rear arch pyrolysis chambers comes from the high-temperature flue gas introduced through the adjustable ventilation holes 2 provided on the flat steel of the membrane water wall in the lower part of the front arch triangular area and the rear arch triangular area in the furnace. A number of groups of ventilation holes 2 are arranged along the membrane water wall. A regulating plate 28 is provided on the ventilation holes 2. On the regulating plate 28, overlapping sliders 29 and channel steels 30 are welded through connecting rods. The sliders 29 are arranged at the front end of the channel steels 30; the channel steels 30 are horizontally arranged and the two sides are arranged in a semi-circular shape and tangent to the steel pipes, which can fully isolate the flame from entering the front and rear arch pyrolysis chambers; adjustable screws 27 are provided on both sides of the regulating plate 28 outside the pyrolysis chamber to control the up and down movement of the regulating plate 28 and drive the up and down movement of the sliders 29. The sliders 29 and the channel steels 30 can adjust the flow rate of the high-temperature flue gas under the drive of the regulating plate 28; when the regulating plate 28 is at the lowest end, both sides of the sliders 29 just completely cooperate with the ventilation holes on the steel pipes and flat steels on both sides, and the high-temperature flue gas flowing into the pyrolysis chamber can be completely blocked. At this time, even during operation, dynamic maintenance of unexpected pyrolysis chamber fittings can be carried out. The regulating plate 28 and the sliders 29 are made of Cr25Ni20Si2 or 310 stainless steel.

[0044] In this embodiment, compressed air dust cleaning devices are arranged in the front arch triangular area and the rear arch triangular area. The compressed air dust cleaning devices are arranged on one side of the spiral pyrolysis device. A number of compressed air nozzles 18 are provided on the compressed air dust cleaning devices. The compressed air dust cleaning devices are horizontally arranged through the left and right walls in the front arch triangular area and the rear arch triangular area to periodically remove the suspended ash particles formed during operation in real time, especially to ensure the removal of the dynamic ash accumulation on the outer shell of the spiral pyrolysis device cylinder and the fins 3 during operation.

[0045] In this embodiment, steel plates 9 lined with refractory materials should be arranged on the opening surfaces of the front and rear arch triangular areas to form an enclosed space for the indirect pyrolysis chamber. Flange structures 10 are arranged above and below the steel plates 9 and form flange connections with the flange structures welded on the upper and lower membrane water walls. The steel plates 9 can be disassembled regularly to clean or wash the stubborn ash adhered to the spiral pyrolysis device and its accessories.

[0046] In this embodiment, the screw conveyor is arranged through the hopper outside the front wall. A number of carbon leakage ports are provided at the lower part of the screw conveyor; when biomass carbon is not required, the collected biomass carbon can be transported through the two-stage screw device into the hopper 1, evenly distributed and then sent to the grate 21 and into the furnace for combustion.

[0047] In this embodiment, solid fuels such as raw biomass, formed biomass, biomass carbon, and coal can be burned on the grate 21. The raw materials input into the spiral pyrolysis device 4 in the indirect pyrolysis chamber of the high-temperature flue gas are raw biomass or formed biomass particles that have been dried and crushed, or urban sludge with a moisture content of < 35% after drying treatment can also be selected.

[0048] In this embodiment, the flue gas ventilation holes 2 arranged on the lower part of the front and rear arch membrane water walls are realized by removing some flat steel in the water wall, and several groups of ventilation holes 2 are arranged from right to left.

[0049] In this embodiment, the air is divided into primary air and secondary air. The primary air and primary flue gas enter the combustion chamber from the bottom of the grate 21. The secondary air enters the ejector device 8 as a high-speed fluid and successively ejects the pyrolyzed flue gas and the pyrolysis gas in the spiral cylinder into the upper arch area to reduce NO in the flue gas with the pyrolysis gas x and then reburn, and realize flue gas recirculation reburn with the pyrolyzed flue gas to reduce NO x .

[0050] When the biomass pyrolysis coupled direct combustion heat and carbon co-production boiler of the present invention operates, straw particles with a particle size of 5 - 10 mm are fed into the grate through the screw feeding device in the hopper and burned. Part of the high-temperature flue gas generated after combustion enters the front and rear arch pyrolysis chambers through the ventilation holes arranged on the lower part of the front and rear arch membrane water walls; the flue gas directly flushes the enhanced heat transfer fins welded on the outside of the spiral cylinder above the ventilation holes in the front and rear arch pyrolysis chambers for heat exchange.

[0051] The spiral pyrolysis device is arranged obliquely and penetratingly from the right wall to the left wall in the front and rear arch pyrolysis chambers. A number of evenly distributed pyrolysis gas ducts are arranged on the spiral pyrolysis device and are communicated with the ejector device; The pine wood particles with a particle size of 6-26 mm, a length of 20-50 mm and a water content of about 15% after drying and crushing enter the spiral pyrolysis device through the feed inlet near the right wall, and exchange heat with the high-temperature flue gas for pyrolysis to produce pyrolysis gas and biomass charcoal; To prevent the pyrolysis gas from escaping from the feed inlet, a duct is provided on the pyrolysis gas duct near the feed inlet of the spiral pyrolysis device to connect with the lower channel of the feed inlet, and two-stage regulation is set at the lower part of the feed inlet. The pyrolysis gas duct is connected with the ejector device.

[0052] In the ejector device, the pyrolyzed flue gas and the pyrolysis gas in the spiral cylinder are successively ejected to the upper arch area by high-speed secondary air to reduce NO in the flue gas with the pyrolysis gas x and then reburn, and the pyrolyzed flue gas is used to realize flue gas recirculation reburning to reduce NO x . A compressed air dust cleaning device is arranged in the front and rear arch pyrolysis chambers to regularly remove the suspended ash particles formed during operation in real time, especially to ensure the removal of the dynamic ash accumulation on the outer shell and fins of the spiral pyrolysis device.

[0053] The biomass charcoal in the spiral pyrolysis device is sent into the biomass charcoal storage device through the charcoal outlet pipe. An inclined spiral output device connected to the screw conveyor is arranged at the lower part of the biomass charcoal storage device, and a number of charcoal leakage ports are arranged at the lower part of the screw conveyor. The biomass carbon can be directly taken out for other uses or transported through two-stage screw devices, evenly distributed into the hopper and then sent into the grate and into the furnace for combustion; thus realizing the diversified utilization of products. The flue gas generated by combustion enters the flue from the upper furnace outlet, and is discharged after heat exchange and subsequent purification treatment.

[0054] In summary, a biomass pyrolysis-coupled direct combustion thermal charcoal co-production boiler provided by the present invention. The original ecological biomass or formed biomass particles after drying and crushing absorb heat in the spiral pyrolysis device in the front and rear arch pyrolysis chambers to produce pyrolysis gas and biomass charcoal. The pyrolyzed flue gas and the pyrolysis gas in the spiral cylinder are successively ejected to the upper arch area by the ejector device arranged on the membrane water-cooled wall on the upper part of the front and rear arches under the action of high-speed secondary air to reduce NO in the flue gas with the pyrolysis gas x and then reburn, and the pyrolyzed flue gas is used to realize flue gas recirculation reburning to reduce NO x, it can fully solve the problems of tar condensation blocking equipment and high nitrogen oxide emissions caused by the pipeline transportation of pyrolysis gas; the biochar enters the biochar storage device through the carbon outlet pipe. An inclined spiral output device connected to the spiral conveyor is provided at the lower part of the biochar storage device, and several carbon leakage ports are provided at the lower part of the spiral conveyor. The biochar can be directly taken out for other uses or transported through two-stage spiral devices, transferred into the hopper, evenly distributed, and then sent to the grate and into the furnace for combustion; thus realizing the diversified utilization of products. The heat required for biomass pyrolysis in the spiral pyrolysis device comes from the high-temperature flue gas introduced through the adjustable ventilation holes provided on the flat steel of the membrane water wall at the lower parts of the front arch and the rear arch in the furnace. By designing the structure of the membrane water wall at the ventilation holes, the regulation of the high-temperature flue gas flow and the isolation of the flame from entering the pyrolysis chambers of the front and rear arches can be achieved. The compressed air dust cleaning device installed in the pyrolysis chambers of the front and rear arches realizes the real-time and regular removal of the suspended ash particles formed during the operation process, especially ensuring the removal of the dynamic ash accumulation on the outer shell and fins of the spiral pyrolysis device cylinder, which can fully guarantee the equipment life and heat exchange efficiency. To provide the heat required for biomass pyrolysis in the spiral cylinder and solve the problems such as the narrow fuel applicability of existing boilers, this boiler is designed as a grate boiler, and solid fuels such as raw biomass, formed biomass, biochar, coal, and sludge can be burned on the grate. In addition, the present invention is provided with air staging control, which can enable the fuel to burn fully while reducing the emissions of pollutants such as nitrogen.

Claims

1. A biomass pyrolysis coupled with direct combustion thermal carbon co-production boiler, characterized in that, It is a grate boiler, including a boiler body Ⅰ and a grate (21). A front arch Ⅱ and a rear arch Ⅳ are arranged between the furnace chamber and the burnout chamber. After the membrane water walls of the front arch Ⅱ and the rear arch Ⅳ are folded into the furnace chamber, a front arch triangular area Ⅲ and a rear arch triangular area Ⅴ are respectively formed. A spiral pyrolysis device (4) and an ejector device (8) are arranged in both the front arch triangular area Ⅲ and the rear arch triangular area Ⅲ. The ejector device (8) communicates with the spiral pyrolysis device (4) and the furnace chamber; outside the boiler body Ⅰ, a hopper (1), a biomass carbon storage device (19), a spiral output device (20) and a spiral conveyor (25) are respectively arranged. The hopper (1) is connected to the grate (21) through a spiral feeding device (24). A primary air duct (23) is arranged below the grate (21); adjustable vent holes (2) are arranged on the lower part of the membrane water walls of the front arch Ⅱ and the rear arch Ⅳ. The spiral pyrolysis device (4) is arranged above the vent holes (2). The output end of the spiral pyrolysis device (4) is communicated with the biomass carbon storage device (19) through a carbon outlet pipe. The bottom of the biomass carbon storage device (19) is connected to the spiral conveyor (25) through the spiral output device (20), and the spiral conveyor (25) is connected to the hopper (1); the spiral pyrolysis device (4) is arranged obliquely through the pyrolysis chambers of the front and rear arches from the right wall to the left wall, and the feed inlet (26) of the spiral pyrolysis device (4) is arranged outside the right wall; in the pyrolysis chambers of the front and rear arches, secondary air is used to eject the pyrolyzed flue gas and the pyrolysis gas in the spiral cylinder to the upper arch area in sequence.

2. The biomass pyrolysis coupled with direct combustion thermal carbon co-production boiler according to claim 1, characterized in that, A number of pyrolysis gas conduits (6) are uniformly arranged on the spiral pyrolysis device (4) and communicated with the ejector device (8), and two-stage regulation is set at the lower part. The first pyrolysis gas conduit (6) near the feed inlet communicates with the lower part of the feed inlet (26). Reinforced heat exchange fins (3) are arranged outside the spiral cylinder of the spiral pyrolysis device (4). The reinforced heat exchange fins are spiral fins, H-shaped fins or pin fins.

3. A hot charcoal co-production boiler for biomass pyrolysis coupled with direct combustion according to claim 1, characterized in that, Each group of ejector devices (8) is also connected to a secondary air duct (7); the ejector device (8) is installed on the upper part of the membrane water walls of the front arch Ⅱ and the rear arch Ⅳ. A secondary air header (17) is arranged at the top of the front arch triangular area Ⅲ and the rear arch triangular area Ⅴ. The secondary air duct (7) connects the secondary air header (17) and the ejector device (8), and the outlet of the ejector device (8) faces the outside of the top of the front arch triangular area Ⅲ and the rear arch triangular area Ⅴ.

4. A hot charcoal co-production boiler for biomass pyrolysis coupled with direct combustion according to claim 1, characterized in that, The heat required for pyrolysis of biomass in the spiral pyrolysis device (4) comes from high-temperature flue gas introduced by adjustable vents (2). The vents (2) are arranged in a plurality of groups along the membrane water-cooled wall. An adjustment plate (28) is arranged on the vents (2) through a connecting rod. A slider (29) and a channel steel (30) are welded on the adjustment plate (28). The slider (29) is arranged at the front end of the channel steel (30). The channel steel (30) is arranged horizontally and its two sides are arranged in a semi-arc shape to be tangent to the steel pipe. Both ends of the adjustment plate (28) extend out of the pyrolysis chamber. In addition, adjustable screws (27) are arranged at both ends of the adjusting plate (28) to control the upward and downward movement of the adjusting plate (28) and drive the slider (29) to move upward and downward. The slider (29) and the channel steel (30) can adjust the high-temperature flue gas flow rate under the drive of the adjusting plate (28). When the adjusting plate (28) is located at the lowest end, the two sides of the slider (29) just completely match the ventilation holes on the steel pipes and the flat steel on both sides. The adjusting plate (28) and the slider (29) are made of Cr25Ni20Si2 or 310 stainless steel.

5. A hot charcoal co-production boiler for biomass pyrolysis coupled with direct combustion according to claim 1, characterized in that, A compressed air cleaning device (5) is provided in the front arch triangular area III and the rear arch triangular area V. The compressed air cleaning device (5) is arranged on one side of the spiral pyrolysis device (4). A plurality of compressed air nozzles (18) are provided on the compressed air cleaning device (5). The compressed air cleaning device (5) is horizontally arranged to penetrate the left and right walls in the front arch triangular area III and the rear arch triangular area V.

6. A biomass pyrolysis coupled with direct combustion thermal carbon co-production boiler according to claim 1, characterized in that, The opening surfaces of the front arch triangular area III and the rear arch triangular area V are provided with steel plates (9) lined with refractory materials to form a closed space of the indirect pyrolysis chamber. Flange structures (10) are provided at the upper and lower ends of the steel plates (9) and are connected to the flange structures welded on the upper and lower membrane water-cooled walls. The steel plates (9) are regularly disassembled to clean or wash the stubborn dust adhering to the spiral pyrolysis device and its accessories.

7. A hot charcoal co-production boiler for biomass pyrolysis coupled with direct combustion according to claim 1, characterized in that, The screw conveying device (25) is arranged through the hopper (1) outside the front wall water-cooled wall (11), and a plurality of charcoal leakage openings are provided at the lower part of the screw conveying device (25); when the biomass charcoal is not needed, the collected biomass charcoal is transferred into the hopper (1) through the two-stage screw device, evenly distributed, and then sent to the grate (21) to enter the furnace for combustion.

8. A biomass pyrolysis coupled with direct combustion heat and char co-production boiler according to claim 1, characterized in that, The input raw materials in the spiral pyrolysis device (4) are dried and crushed original ecological biomass, formed biomass particles or dried urban sludge with a moisture content of less than about 35%.

9. A hot charcoal co-production boiler for biomass pyrolysis coupled with direct combustion according to claim 1, characterized in that, The flue gas vents (2) provided on the lower membrane water-cooled walls of the front arch II and the rear arch IV are realized by removing part of the flat steel in the lower membrane water-cooled walls, and the vents (2) are provided in a plurality of groups from right to left.

10. A hot charcoal co-production boiler for biomass pyrolysis coupled with direct combustion according to claim 1, characterized in that, A slag condensing tube bundle (13) is arranged in the flue at the furnace outlet, and a high-temperature economizer (14) and a low-temperature economizer (16) are arranged in sequence in the flue outside the furnace.

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