A biomass decoupling combustion device and method

Abstract

The present invention provides a biomass decoupled combustion device and method, the device includes a furnace body surrounded by furnace walls, a partition wall longitudinally arranged in the furnace body, a special-shaped partition connected to the lower part of the partition wall, a ventilation grate located in the lower part of the furnace body and a rear fire wall; one side of the partition wall includes a drying zone, a pyrolysis gasification zone and a semi-coke zone from top to bottom, and the other side of the partition wall includes a reducing combustion zone and a burnout zone from bottom to top, and the bottoms of the semi-coke zone and the reducing combustion zone are connected; a half opening is provided in the middle and lower part of the special-shaped partition, and an adjusting air outlet is provided in the reducing combustion zone. The present invention adds a special-shaped partition to the existing combustion device to control the thickness and distribution of the material layer in the semi-coke zone, and divides the tail flue gas into a reducing combustion zone and a burnout zone, so as to control the reducing atmosphere conditions in the reducing combustion zone and reduce NO x The generation of biomass can achieve clean combustion; the present invention can effectively improve the control of the combustion process, enhance the adaptability to the fuel, and reduce the impact of combustion periodicity.

Description

Technical Field

[0001] The invention belongs to the technical field of fuel combustion, and relates to a biomass decoupled combustion device and method. Background Art

[0002] With the depletion of fossil energy and the increasing environmental protection requirements, the development and utilization of renewable energy has attracted much attention. As a renewable energy, biomass has rich energy storage. Its development and utilization can effectively mitigate the greenhouse effect. However, due to its low volume density and large stacking volume, it is difficult to store and transport. In addition, it has a high volatile content, asynchronous combustion, and serious black smoke. The existing combustion equipment often has a low combustion efficiency, which restricts the combustion and utilization of biomass.

[0003] In conventional small and medium-sized decoupled combustion devices, the NO generated during the combustion process can be reduced by reducing the pyrolysis zone and semi-coke zone. x , especially the form, size and ventilation volume of the semi-coke zone have a great influence on the performance of small and medium-sized coal-fired decoupled combustion devices; however, for various types of biomass fuels, due to the high volatile matter content, low fixed carbon content, small volume and low temperature of the semi-coke zone, it has little effect on controlling the generation of soot from light volatiles, but has a great influence on suppressing NO during combustion. x At the same time, the semi-coke area has a smaller volume and lower temperature, and the requirements for ventilation control are also higher. Otherwise, it is easy to cause the combustion process to be unstable, and the combustion temperature and the composition of flue gas emissions will show obvious periodic changes.

[0004] CN 103471089A discloses a coal-fired decoupled combustion device and a combustion method. The device comprises a furnace body and a wind chamber located below the furnace body. The furnace body comprises an upper partition wall, a first lower partition wall located below the upper partition wall and arranged on both inner and outer sides, wherein a first grate is arranged between the top of the inner first lower partition wall and the furnace body side wall, and a second grate is arranged between the first lower partition wall and the bottom of the second lower partition wall; a gasification pyrolysis zone and a semi-coke zone are formed between the upper part of the first grate and the upper partition wall, the semi-coke zone is located below the gasification pyrolysis zone, and a coke zone is formed between the first lower partition wall and the second lower partition wall; the device is mainly used for the decoupled combustion of coal-fired fuel, and is not suitable for the combustion of biomass with high volatile matter and high nitrogen content, which often produces NO x High content of smoke.

[0005] CN 101270875A discloses a biomass shaped fuel decoupled combustion device and a combustion method thereof, wherein the device comprises a vertical combustion furnace and a combustion chamber and a pyrolysis chamber which are connected at the bottom, a hopper is arranged above the pyrolysis chamber, a grate is arranged at the bottom of the combustion chamber, a screw conveyor is arranged at the bottom of the pyrolysis chamber, a smoke interlayer is arranged on the outer wall of the pyrolysis chamber, the smoke interlayer is connected with a smoke channel arranged on the furnace body, an air duct is arranged below the grate, a smoke guide plate is arranged in the combustion chamber, and the top of the smoke guide plate is connected with the smoke interlayer; although the device performs pyrolysis and combustion of biomass in different regions, the regional division does not clearly define the semi-coke region, the semi-coke region and the combustion region belong to the same region, which makes it difficult to accurately control the temperature and ventilation volume, thus affecting the combustion efficiency of the biomass.

[0006] In summary, for the structural design of the biomass decoupling combustion device, it is necessary to add a gas combustion area to facilitate the removal of NO in the pyrolysis gas. x Fully restore, reduce pollutant emissions from biomass combustion, and improve fuel utilization efficiency. Summary of the invention

[0007] In view of the problems existing in the prior art, the purpose of the present invention is to provide a biomass decoupled combustion device and method. The device can control the thickness and distribution of the material layer entering the reduction combustion zone from the semi-coke zone by dividing the furnace body into multiple reaction zones, especially by setting special-shaped partitions, so as to facilitate the control of the semi-coke combustion process and enhance the combustion stability of the device and its adaptability to fuel.

[0008] To achieve this object, the present invention adopts the following technical solutions:

[0009] In one aspect, the present invention provides a biomass decoupled combustion device, the decoupled combustion device comprising a furnace body surrounded by furnace walls, a partition wall longitudinally arranged in the furnace body, a special-shaped partition plate connected to the lower part of the partition wall, a ventilation grate and a rear fire wall;

[0010] The partition wall extends from the top of the furnace body to the middle and lower part of the furnace body. One side of the partition wall includes a drying zone, a pyrolysis gasification zone and a semi-coke zone from top to bottom. The lower part of the semi-coke zone is the ventilation grate. The other side of the partition wall includes a reduction combustion zone and a burnout zone from bottom to top. The lower part of the reduction combustion zone is the rear fire wall. A gap is left between the lower part of the special-shaped partition plate and the ventilation grate to form a fire port, connecting the bottom of the semi-coke zone and the reduction combustion zone;

[0011] A half opening is arranged at the lower part of the special-shaped partition, and the edge of the half opening is located on the bottom side of the special-shaped partition.

[0012] In the present invention, the decoupled combustion device is designed according to the composition characteristics of biomass fuel. By adding a special-shaped baffle and a reaction area of ​​the reduction combustion zone on the basis of the existing decoupled combustion device, the structural design of the special-shaped baffle can make the pyrolysis gasification gas and the semi-coke combustion flue gas enter the reduction combustion zone better, and at the same time control the thickness of the semi-coke material layer entering the reduction combustion zone to be different, thereby adjusting the amount of air entering the reduction combustion zone at different positions, facilitating the control of the atmosphere conditions in the reduction combustion zone, so that the reducing gas in the pyrolysis gasification gas will react to generate NO x Reduction and reduction of NO in biomass combustion x emissions; at the same time, the structural design of the device can improve the stability of fuel combustion, reduce the impact of combustion periodicity, and improve the utilization efficiency of biomass.

[0013] The following are preferred technical solutions of the present invention, but are not intended to be limitations of the technical solutions provided by the present invention. Through the following technical solutions, the technical objectives and beneficial effects of the present invention can be better achieved and realized.

[0014] As a preferred technical solution of the present invention, the two side furnace walls parallel to the partition wall are respectively the front furnace wall and the rear furnace wall, the furnace wall on the biomass feeding side is the front furnace wall, and the rear fire wall is located on the rear furnace wall.

[0015] In the present invention, the front furnace wall and the rear furnace wall are named according to the position where the fuel is added and the moving direction during the reaction.

[0016] Preferably, the furnace area below the ventilation grate and the rear fire wall is an ash and slag area.

[0017] In the present invention, according to the distance from the ventilation grate to the furnace top and the total height of the partition wall and the special-shaped partition, the distance from the bottom of the special-shaped partition to the ventilation grate can be known, which is the control of the thickness of the upper coke layer on the grate.

[0018] As a preferred technical solution of the present invention, the half opening of the special-shaped partition is a region with a short upper side and a long lower side.

[0019] Preferably, the shape of the half opening of the special-shaped partition is a trapezoid or a semicircle, preferably an isosceles trapezoid.

[0020] Preferably, the half-opening height of the special-shaped partition is 1 / 5 to 4 / 5 of the total height of the special-shaped partition, for example, 1 / 5, 3 / 10, 2 / 5, 1 / 2, 3 / 5, 7 / 10 or 4 / 5, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0021] Preferably, viewed from the length direction of the special-shaped partition, the half opening is located in the middle of the special-shaped partition and is bilaterally symmetrical about the central axis of the special-shaped partition.

[0022] Preferably, an opening is additionally provided above the half opening of the special-shaped partition.

[0023] In the present invention, the design of the special-shaped partition is to set a half opening at the bottom, so that the gas generated by the pyrolysis gasification zone and the semi-coke zone can enter the reduction combustion zone from the opening instead of only entering through the fire port above the grate, thereby reducing the ventilation resistance of the grate; and by setting another opening above the half opening, the ventilation capacity of the upper middle part of the special-shaped partition can be further enhanced, thereby enhancing the adaptability to the fuel.

[0024] In the present invention, the middle and lower openings of the special-shaped partition are designed so that the material layer thickness between the special-shaped partition and the ventilation grate is different. The material layer thickness in the middle part is large, and the ventilation volume entering the reduction combustion zone through the ventilation grate is small, while the coal gas generated in the pyrolysis gasification zone enters the reduction combustion zone through the half opening of the special-shaped partition or other openings above the half opening in a large amount; the material layer thickness of the parts close to the furnace wall on both sides is small, and the ventilation volume entering the reduction combustion zone through the ventilation grate is large, while the pyrolysis gasification coal gas enters the reduction combustion zone through the lower part of the special-shaped partition in a small amount.

[0025] Preferably, the special-shaped partition plate and the partition wall are not fixedly connected, and are preferably connected in a hanging manner.

[0026] In the present invention, the special-shaped partition plate is detachably connected to the partition wall, so that it is convenient to adjust and replace it according to the needs.

[0027] As a preferred technical solution of the present invention, the ventilation grate is arranged to be inclined downward along the direction from the front furnace wall to the rear furnace wall, and extends to the lower end position of the rear fire wall.

[0028] Preferably, the inclination angle of the ventilation grate is 0 to 60 degrees with the horizontal direction, for example 0 degrees, 5 degrees, 10 degrees, 15 degrees, 20 degrees, 25 degrees, 30 degrees, 40 degrees, 50 degrees or 60 degrees, but is not limited to the listed values. Other unlisted values ​​within the numerical range are also applicable, preferably an angle of 5 to 30 degrees.

[0029] In the present invention, the ventilation grate is tilted to accelerate the moving speed of the semi-coke on the grate, appropriately increase the amount of semi-coke that can enter the reduction combustion zone, and reduce the difficulty of air passing through the ventilation grate.

[0030] As a preferred technical solution of the present invention, a heat insulating layer is provided around the reducing combustion zone, and the heat insulating layer is located on the side walls of the furnace wall and the partition wall in contact with the reducing combustion zone.

[0031] In the present invention, a heat insulating layer is provided in the reduction combustion zone, which can ensure that the reaction temperature of the reduction combustion zone is stabilized in a higher range, accelerate the reaction rate, and reduce the influence of the combustion periodicity on the reaction stability of the zone.

[0032] Preferably, an adjusting air outlet is provided on the lower furnace wall of the reduction combustion zone, and a burnout air outlet is provided on the upper furnace wall.

[0033] In the present invention, the air entering the reducing combustion zone is mixed with the pyrolysis gasified coal gas and burned in the reducing combustion zone. The combustion-supporting air can be supplemented by adjusting the air inlet to control the combustion zone as a whole to burn under the optimal reducing atmosphere. Most of the fuel nitrogen in the flue gas generated has been converted, but it still contains a large amount of unburned CO and other combustibles. Excess air is introduced through the burnout air inlet to burn the remaining combustibles in the burnout zone.

[0034] In another aspect, the present invention provides a method for performing decoupled combustion of biomass using the above device, the method comprising the following steps:

[0035] (1) After the biomass fuel enters the decoupled combustion device, it undergoes drying, pyrolysis and gasification, and semi-coke combustion processes in sequence during its downward movement, generating pyrolysis and gasification coal gas and semi-coke combustion flue gas;

[0036] (2) The semi-coke moves along with the ventilation grate into the lower part of the reduction combustion zone for further combustion, and the pyrolysis gasification gas and the semi-coke combustion flue gas enter the reduction combustion zone through the special-shaped partition plate, and are mixed and burned with the air introduced through the ventilation grate to obtain mixed flue gas;

[0037] (3) The mixed flue gas obtained in step (2) is mixed with air and fully burned to obtain burnt flue gas.

[0038] As a preferred technical solution of the present invention, the drying, pyrolysis gasification and semi-coke combustion processes in step (1) are carried out in the drying zone, pyrolysis gasification zone and semi-coke zone respectively.

[0039] In the present invention, after the biomass fuel is fed into the furnace body, it first passes through the drying area, then through the pyrolysis and gasification area to the lower semi-coke area, and completes the drying, pyrolysis and gasification and semi-coke combustion processes in sequence. The fixed ash produced by the semi-coke combustion enters the ash area through the ventilation grate; the pyrolysis and gasification coal gas and the flue gas produced by the semi-coke combustion enter the reduction combustion area from below the special-shaped partition.

[0040] Preferably, the temperature of the drying process in step (1) is 100-200°C, for example, 100°C, 120°C, 140°C, 150°C, 160°C, 180°C or 200°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0041] Preferably, the temperature of the pyrolysis and gasification process in step (1) is 300-900°C, for example, 300°C, 400°C, 500°C, 600°C, 700°C, 800°C or 900°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0042] Preferably, the temperature of the semi-coke combustion process in step (1) is 500-1100°C, for example, 500°C, 600°C, 700°C, 800°C, 900°C, 1000°C or 1100°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0043] As a preferred technical solution of the present invention, the semi-coke generated after the pyrolysis and gasification in step (1) falls onto the ventilation grate and is mixed with the air introduced from the ventilation grate to perform semi-coke combustion.

[0044] Preferably, the composition of the pyrolysis gasification coal gas in step (1) includes NH3 and reducing hydrocarbons.

[0045] As a preferred technical solution of the present invention, the ash produced after the combustion of the semi-coke in step (1) and step (2) enters the ash area below the ventilation grate.

[0046] Preferably, the thickness of the semi-coke layer passing through the half-opening of the special-shaped partition is greater than the thickness of the semi-coke layer passing through the areas on both sides of the half-opening of the special-shaped partition.

[0047] In the present invention, at the lower half opening of the special-shaped partition, the material layer thickness and semi-coke volume are relatively large, and the reducing atmosphere concentration is relatively large, which is beneficial to inhibit NO x The air ventilation volume is large in the area with smaller material layer thickness at the bottom of the special-shaped partition. At the same time, the oxygen concentration of the air decreases and the temperature increases after burning in the semi-coke layer, which can provide an oxidant with uniform concentration and higher temperature for the reducing combustion zone. The pyrolysis gasification gas burns in a low-oxygen and high-temperature atmosphere, which is beneficial to accelerate the conversion of fuel nitrogen into N2.

[0048] In the present invention, due to the continuous change in the thickness of the material layer at the bottom of the special-shaped baffle, there is always a continuous change in the upper and lower ventilation volume and combustion components in this area, ensuring the existence of a core combustion zone under discontinuous flow of materials to provide sufficient combustion heat and maintain the furnace temperature, which is beneficial to increase the stability of combustion and reduce the impact of combustion periodicity.

[0049] Preferably, the combustion temperature of the reducing combustion zone in step (2) is 900-1100°C, for example, 900°C, 925°C, 950°C, 980°C, 1000°C, 1020°C, 1050°C, 1080°C or 1100°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0050] Preferably, during the mixed combustion in step (2), air is introduced from the regulating air port to assist combustion.

[0051] Preferably, the excess air coefficient of the reducing combustion zone in step (2) is 0.6 to 0.95, for example, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9 or 0.95, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0052] In the present invention, after the combustion in the reduction combustion zone, most of the fuel nitrogen in the mixed flue gas generated has been converted, but it still contains a large amount of unburned CO and other combustibles, and its composition includes CO, N2 and CO2, etc., and there may still be a small amount of NO x , excess air is introduced through the burnout air vent to allow the remaining combustibles to burn out in the burnout zone.

[0053] As a preferred technical solution of the present invention, preferably, the combustion temperature in step (3) is 1000-1300°C, for example, 1000°C, 1030°C, 1050°C, 1080°C, 1100°C, 1120°C, 1150°C, 1180°C, 1200°C, 1250°C or 1300°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0054] Preferably, the air in step (3) is introduced from the burnout air vents provided on the furnace wall.

[0055] Preferably, the excess air coefficient during combustion after the air is introduced in step (3) is 1.05 to 2, for example 1.05, 1.2, 1.4, 1.5, 1.6, 1.8 or 2, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0056] Compared with the prior art, the present invention has the following beneficial effects:

[0057] (1) The device of the present invention can control the thickness and distribution of the material layer entering the reducing combustion zone from the semi-coke zone by adding a special-shaped baffle to the existing decoupled combustion device and dividing the reducing combustion zone, thereby adjusting the amount of air entering the reducing combustion zone from different positions, making it easier to control the reducing atmosphere conditions in the reducing combustion zone and reduce NO x The amount of biomass fuel generated can be reduced to achieve harmless combustion and utilization, and the combustion efficiency can reach more than 90%;

[0058] (2) The structural design of the device described in the present invention can effectively improve the control of the semi-coke combustion process, enhance the stability of the combustion process and the adaptability to the fuel, and reduce the impact of the combustion periodicity. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] Figure 1 is a schematic structural diagram of a biomass decoupled combustion device provided in Example 1 of the present invention;

[0060] Figure 2 is a schematic structural diagram of a special-shaped partition provided in Example 1 of the present invention;

[0061] Among them, 1-front furnace wall, 2-partition wall, 3-rear furnace wall, 4-special-shaped partition, 5-ventilation grate, 6-rear fire wall, 7-drying zone, 8-pyrolysis gasification zone, 9-semi-coke zone, 10-ash zone, 11-reduction combustion zone, 12-burnout zone, 13-adjusting air outlet, 14-burnout air outlet, 15-insulation layer. DETAILED DESCRIPTION

[0062] In order to better illustrate the present invention and facilitate understanding of the technical solution of the present invention, the present invention is further described in detail below. However, the following embodiments are only simple examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention shall be subject to the claims.

[0063] The following are typical but non-limiting embodiments of the present invention:

[0064] Embodiment 1:

[0065] This embodiment provides a biomass decoupled combustion device. The structural schematic diagram of the device is as follows: Figure 1 As shown, it comprises a furnace body surrounded by furnace walls, a partition wall 2 longitudinally arranged in the furnace body, a special-shaped partition plate 4 connected to the lower part of the partition wall 2, a ventilation grate 5 and a rear fire wall 6;

[0066] The partition wall 2 extends from the top of the furnace body to the middle and lower part of the furnace body, dividing the furnace body into two parts. One side of the partition wall 2 includes a drying area 7, a pyrolysis gasification area 8 and a semi-coke area 9 from top to bottom, and the lower part of the semi-coke area 9 is the ventilation grate 5. The other side of the partition wall 2 includes a reduction combustion area 11 and a burnout area 12 from bottom to top, and the lower part of the reduction combustion area 11 is the rear fire wall 6. A gap is left between the lower part of the special-shaped partition plate 4 and the ventilation grate 5 to form a fire port, connecting the bottom of the semi-coke area 9 and the reduction combustion area 11;

[0067] The structural schematic diagram of the special-shaped partition 4 is as follows Figure 2 As shown, a half opening is provided at the lower part, and the edge of the half opening is located on the bottom edge of the special-shaped partition plate 4.

[0068] The furnace walls on both sides parallel to the partition wall 2 are respectively a front furnace wall 1 and a rear furnace wall 3 , the furnace wall on the biomass feeding side is the front furnace wall 1 , and the rear fire wall 6 is located on the rear furnace wall 3 .

[0069] The furnace area below the ventilation grate 5 and the rear fire wall 6 is an ash area 10 .

[0070] The half opening of the shaped partition 4 is an isosceles trapezoid with a short upper side and a long lower side, and the height of the half opening accounts for 2 / 5 of the total height of the shaped partition 4; from the length direction of the shaped partition 4, the half opening is located in the middle of the shaped partition 4.

[0071] The special-shaped partition plate 4 is connected to the partition wall 2 in a hanging manner.

[0072] The ventilation grate 5 is arranged to be tilted downward from the direction from the front furnace wall 1 to the rear furnace wall 3, and extends to the lower end of the rear fire wall 6; the inclination angle of the ventilation grate 5 is 10 degrees with the horizontal direction.

[0073] A heat insulating layer 15 is provided around the reducing combustion zone 11 , and the heat insulating layer 15 is located on the side wall where the furnace wall, the partition wall 2 and the reducing combustion zone 11 are in contact.

[0074] The lower furnace wall of the reduction combustion zone 11 is provided with an adjusting air port 13 , and the upper furnace wall is provided with a burnout air port 14 .

[0075] Embodiment 2:

[0076] This embodiment provides a biomass decoupled combustion device, which includes a furnace body surrounded by furnace walls, a partition wall 2 longitudinally arranged in the furnace body, a special-shaped partition plate 4 connected to the lower part of the partition wall 2, a ventilation grate 5 and a rear fire wall 6;

[0077] The partition wall 2 extends from the top of the furnace body to the middle and lower part of the furnace body, dividing the furnace body into two parts. One side of the partition wall 2 includes a drying area 7, a pyrolysis gasification area 8 and a semi-coke area 9 from top to bottom, and the lower part of the semi-coke area 9 is the ventilation grate 5. The other side of the partition wall 2 includes a reduction combustion area 11 and a burnout area 12 from bottom to top, and the lower part of the reduction combustion area 11 is the rear fire wall 6. A gap is left between the lower part of the special-shaped partition plate 4 and the ventilation grate 5 to form a fire port, connecting the bottom of the semi-coke area 9 and the reduction combustion area 11;

[0078] The lower part of the special-shaped partition plate 4 is provided with a half opening, and the edge of the half opening is located on the bottom side of the special-shaped partition plate 4 .

[0079] The furnace walls on both sides parallel to the partition wall 2 are respectively a front furnace wall 1 and a rear furnace wall 3 , the furnace wall on the biomass feeding side is the front furnace wall 1 , and the rear fire wall 6 is located on the rear furnace wall 3 .

[0080] The furnace area below the ventilation grate 5 and the rear fire wall 6 is an ash area 10 .

[0081] The half opening of the shaped partition 4 is a semicircle with a bottom edge as the diameter, and the height of the half opening accounts for 4 / 5 of the total height of the shaped partition 4. From the length direction of the shaped partition 4, the half opening is located in the middle of the shaped partition 4; an opening is also provided above the half opening of the shaped partition 4.

[0082] The special-shaped partition plate 4 is connected to the partition wall 2 in a hanging manner.

[0083] The ventilation grate 5 is arranged to be tilted downward from the direction from the front furnace wall 1 to the rear furnace wall 3, and extends to the lower end of the rear fire wall 6; the inclination angle of the ventilation grate 5 is 30 degrees with the horizontal direction.

[0084] A heat insulating layer 15 is provided around the reducing combustion zone 11 , and the heat insulating layer 15 is located on the side wall where the furnace wall, the partition wall 2 and the reducing combustion zone 11 are in contact.

[0085] The lower furnace wall of the reduction combustion zone 11 is provided with an adjusting air port 13 , and the upper furnace wall is provided with a burnout air port 14 .

[0086] Embodiment 3:

[0087] This embodiment provides a biomass decoupled combustion method, which is performed using the device in Embodiment 1 and includes the following steps:

[0088] (1) After the biomass fuel enters the decoupled combustion device, it is dried, pyrolyzed and gasified, and semi-coke burned in sequence during its downward movement. The temperature of the drying process is 150°C, the temperature of the pyrolysis and gasification process is 550°C, and the temperature of the semi-coke burning process is 800°C, generating pyrolysis and gasification coal gas and semi-coke combustion flue gas. The composition of the pyrolysis and gasification coal gas includes NH3 and reducing hydrocarbons. The semi-coke generated after the pyrolysis and gasification falls onto the ventilation grate 5 and is mixed with the air introduced from the ventilation grate 5 to perform semi-coke combustion.

[0089] (2) The pyrolysis gasification coal gas and the semi-coke combustion flue gas enter the reduction combustion zone 11 through the special-shaped partition 4, and are mixed and burned with the air introduced through the ventilation grate 5. The semi-coke enters the lower part of the reduction combustion zone 11 with the movement of the ventilation grate 5 for further combustion. The thickness of the semi-coke material layer passing through the semi-opening of the special-shaped partition 4 is greater than the thickness of the semi-coke material layer passing through the areas on both sides of the semi-opening of the special-shaped partition 4. The combustion temperature of the reduction combustion zone is 1000° C. During the mixed combustion, air is introduced from the regulating air port 13 to assist combustion. The excess air coefficient of the reduction combustion zone 11 is 0.8, and mixed flue gas is obtained;

[0090] (3) The mixed flue gas obtained in step (2) is mixed with air introduced through the burnout air port 14 for full combustion, wherein the mixed flue gas comprises CO, N2 and CO2, the combustion temperature is 1100°C, the excess air coefficient during combustion is 1.5, and burnout flue gas is obtained.

[0091] In this embodiment, the biomass fuel is decoupled and burned by the above method, and the fuel combustion efficiency reaches 92%, and the NO in the flue gas is x The content meets the emission requirements.

[0092] Embodiment 4:

[0093] This embodiment provides a biomass decoupled combustion method, which is performed using the device in Embodiment 1 and includes the following steps:

[0094] (1) After the biomass fuel enters the decoupled combustion device, it is dried, pyrolyzed and gasified, and semi-coke burned in sequence during its downward movement. The temperature of the drying process is 200°C, the temperature of the pyrolysis and gasification process is 800°C, and the temperature of the semi-coke burning process is 1000°C, generating pyrolysis and gasification coal gas and semi-coke combustion flue gas. The composition of the pyrolysis and gasification coal gas includes NH3 and reducing hydrocarbons. The semi-coke generated after the pyrolysis and gasification falls onto the ventilation grate 5 and is mixed with the air introduced from the ventilation grate 5 to perform semi-coke combustion.

[0095] (2) The pyrolysis gasification coal gas and the semi-coke combustion flue gas enter the reduction combustion zone 11 through the special-shaped partition 4, and are mixed and burned with the air introduced through the ventilation grate 5. The semi-coke enters the lower part of the reduction combustion zone 11 with the movement of the ventilation grate 5 for further combustion. The thickness of the semi-coke layer passing through the semi-opening of the special-shaped partition 4 is greater than the thickness of the semi-coke layer passing through the areas on both sides of the semi-opening of the special-shaped partition 4. The combustion temperature of the reduction combustion zone is 1100° C. During the mixed combustion, air is introduced from the regulating air port 13 to assist combustion. The excess air coefficient of the reduction combustion zone 11 is 0.9 to obtain mixed flue gas.

[0096] (3) The mixed flue gas obtained in step (2) is mixed with air introduced through the burnout air port 14 for full combustion, wherein the mixed flue gas comprises CO, N2 and CO2, the combustion temperature is 1300°C, the excess air coefficient during combustion is 1.1, and burnout flue gas is obtained.

[0097] In this embodiment, the biomass fuel is decoupled and burned by the above method, and the fuel combustion efficiency reaches 94%, and the NO in the flue gas is x The content meets the emission requirements.

[0098] Embodiment 5:

[0099] This embodiment provides a biomass decoupled combustion method, which is performed using the device in Embodiment 2 and includes the following steps:

[0100] (1) After the biomass fuel enters the decoupled combustion device, it is dried, pyrolyzed and gasified, and semi-coke burned in sequence during its downward movement. The temperature of the drying process is 100°C, the temperature of the pyrolysis and gasification process is 400°C, and the temperature of the semi-coke burning process is 600°C, generating pyrolysis and gasification coal gas and semi-coke combustion flue gas. The composition of the pyrolysis and gasification coal gas includes NH3 and reducing hydrocarbons. The semi-coke generated after the pyrolysis and gasification falls onto the ventilation grate 5 and is mixed with the air introduced from the ventilation grate 5 to perform semi-coke combustion.

[0101] (2) The pyrolysis gasification coal gas and the semi-coke combustion flue gas enter the reduction combustion zone 11 through the special-shaped partition 4, and are mixed and burned with the air introduced through the ventilation grate 5. The semi-coke enters the lower part of the reduction combustion zone 11 with the movement of the ventilation grate 5 for further combustion. The thickness of the semi-coke material layer passing through the semi-opening of the special-shaped partition 4 is greater than the thickness of the semi-coke material layer passing through the areas on both sides of the semi-opening of the special-shaped partition 4. The combustion temperature of the reduction combustion zone is 900° C. During the mixed combustion, air is introduced from the regulating air port 13 to assist combustion. The excess air coefficient of the reduction combustion zone 11 is 0.6, and mixed flue gas is obtained;

[0102] (3) The mixed flue gas obtained in step (2) is mixed with air introduced through the burnout air port 14 for full combustion, wherein the mixed flue gas comprises CO, N2 and CO2, the combustion temperature is 1000°C, the excess air coefficient during combustion is 1.8, and burnout flue gas is obtained.

[0103] In this embodiment, the biomass fuel is decoupled and burned by the above method, and the fuel combustion efficiency reaches 90.5%, and the NO in the flue gas is x The content meets the emission requirements.

[0104] Comparative Example 1:

[0105] This comparative example provides a biomass decoupled combustion device, the structure of which refers to the structure of the device in Example 1, with the only difference being that the device does not include a special-shaped baffle 4, and the reducing combustion zone 11 is not provided with an adjusting air port 13.

[0106] The device is used for decoupled combustion of biomass. When the semi-coke moves with the ventilation grate, the thickness of the semi-coke layer at different positions is basically the same. When the pyrolysis gasification gas and the semi-coke combustion flue gas pass through the burner, the resistance is large, the air is difficult to enter, and it is difficult to control the atmosphere conditions during further combustion, which makes the fuel combustion efficiency low, and finally burns out NO in the flue gas. x The content is relatively high and cannot meet emission standards.

[0107] According to the above embodiments and comparative examples, the device of the present invention can control the thickness and distribution of the material layer entering the reducing combustion zone from the semi-coke zone by adding a special-shaped baffle on the basis of the existing decoupled combustion device and dividing the reducing combustion zone, thereby adjusting the amount of air entering the reducing combustion zone from different positions, making it easier to control the reducing atmosphere conditions in the reducing combustion zone and reduce NO x The amount of production can be reduced to achieve harmless combustion and utilization of biomass fuel, and the combustion efficiency can reach more than 90%; the structural design of the device can effectively improve the control of the semi-coke combustion process, enhance the stability of the combustion process and the adaptability to the fuel, and reduce the impact of combustion periodicity.

[0108] The applicant declares that the present invention uses the above embodiments to illustrate the detailed devices and methods of the present invention, but the present invention is not limited to the above detailed devices and methods, that is, it does not mean that the present invention must rely on the above detailed devices and methods to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of the device of the present invention, addition of auxiliary devices, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A biomass decoupled combustion device, characterized in that: The decoupled combustion device comprises a furnace body surrounded by furnace walls, a partition wall longitudinally arranged in the furnace body, a special-shaped partition plate connected to the lower part of the partition wall, a ventilation grate and a rear fire wall; The partition wall extends from the top of the furnace body to the middle and lower part of the furnace body. One side of the partition wall includes a drying zone, a pyrolysis gasification zone and a semi-coke zone from top to bottom. The lower part of the semi-coke zone is the ventilation grate. The other side of the partition wall includes a reduction combustion zone and a burnout zone from bottom to top. The lower part of the reduction combustion zone is the rear fire wall. A gap is left between the lower part of the special-shaped partition plate and the ventilation grate to form a fire port, connecting the bottom of the semi-coke zone and the reduction combustion zone. The ventilation grate is arranged to be inclined downward from the direction from the front furnace wall to the rear furnace wall, and extends to the lower end of the rear fire wall. A half opening is provided at the lower part of the special-shaped partition, and the edge of the half opening is located on the bottom edge of the special-shaped partition. The half opening of the special-shaped partition is an area with a short upper side and a long lower side. The height of the half opening of the special-shaped partition accounts for 1 / 5 to 4 / 5 of the total height of the special-shaped partition. From the length direction of the special-shaped partition, the half opening is located in the middle of the special-shaped partition.

2. The decoupled combustion device according to claim 1, characterized in that: The furnace walls on both sides parallel to the partition wall are respectively a front furnace wall and a rear furnace wall, the furnace wall on the biomass feeding side is the front furnace wall, and the rear fire wall is located on the rear furnace wall.

3. The decoupled combustion device according to claim 1, characterized in that: The furnace area below the ventilation grate and the rear fire wall is an ash and slag area.

4. The decoupled combustion device according to claim 1, characterized in that: The shape of the half opening of the special-shaped partition is trapezoidal or semicircular.

5. The decoupled combustion device according to claim 4, characterized in that: The shape of the half opening of the special-shaped partition is an isosceles trapezoid.

6. The decoupled combustion device according to claim 1, characterized in that: The special-shaped partition board and the partition wall are not fixedly connected, but connected in a hanging manner.

7. The decoupled combustion device according to claim 1, characterized in that: The inclination angle of the ventilation grate is 0 to 60 degrees with the horizontal direction.

8. The decoupled combustion device according to claim 7, characterized in that: The inclination angle of the ventilation grate is 5 to 30 degrees with the horizontal direction.

9. The decoupled combustion device according to claim 1, characterized in that: A heat insulation layer is arranged around the reduction combustion zone, and the heat insulation layer is located on the side wall where the furnace wall, the partition wall and the reduction combustion zone are in contact.

10. The decoupled combustion device according to claim 1, characterized in that: The lower furnace wall of the reduction combustion zone is provided with an adjusting air port, and the upper furnace wall is provided with a burnout air port.

11. A method for decoupled combustion of biomass using the device according to any one of claims 1 to 10, characterized in that: The method comprises the following steps: (1) After the biomass fuel enters the decoupled combustion device, it undergoes drying, pyrolysis and gasification, and semi-coke combustion processes in sequence during its downward movement, generating pyrolysis and gasification coal gas and semi-coke combustion flue gas; (2) The semi-coke moves along with the ventilation grate into the lower part of the reduction combustion zone for further combustion, and the pyrolysis gasification gas and the semi-coke combustion flue gas enter the reduction combustion zone through the special-shaped partition plate, and are mixed and burned with the air introduced through the ventilation grate to obtain mixed flue gas; (3) The mixed flue gas obtained in step (2) is mixed with air and fully burned to obtain burnt flue gas.

12. The decoupled combustion method according to claim 11, characterized in that: The drying, pyrolysis and gasification and semi-coke combustion processes in step (1) are carried out in the drying zone, pyrolysis and gasification zone and semi-coke zone respectively.

13. The decoupled combustion method according to claim 11, characterized in that: The temperature of the drying process in step (1) is 100-200°C.

14. The decoupled combustion method according to claim 11, characterized in that: The temperature of the pyrolysis and gasification process in step (1) is 300-900°C.

15. The decoupled combustion method according to claim 11, characterized in that: The temperature of the semi-coke combustion process in step (1) is 500-1100°C.

16. The decoupled combustion method according to claim 11, characterized in that: The semi-coke generated after the pyrolysis and gasification in step (1) falls onto the ventilation grate and mixes with the air introduced from the ventilation grate to be burned.

17. The decoupled combustion method according to claim 11, characterized in that: The composition of the pyrolysis gasification coal gas in step (1) includes NH3 and reducing hydrocarbons.

18. The decoupled combustion method according to claim 11, characterized in that: The ash produced after the combustion of the semi-coke in step (1) and step (2) enters the ash area below the ventilation grate.

19. The decoupled combustion method according to claim 11, characterized in that: The thickness of the semi-coke layer passing through the half opening of the special-shaped partition is greater than the thickness of the semi-coke layer passing through the areas on both sides of the half opening of the special-shaped partition.

20. The decoupled combustion method according to claim 11, characterized in that: The combustion temperature of the reduction combustion zone in step (2) is 900-1100°C.

21. The decoupled combustion method according to claim 11, characterized in that: During the mixed combustion in step (2), air is introduced from the regulating air port to assist combustion.

22. The decoupled combustion method according to claim 11, characterized in that: The excess air coefficient of the reducing combustion zone in step (2) is 0.6 to 0.

95.

23. The decoupled combustion method according to claim 11, characterized in that: The combustion temperature in step (3) is 1000-1300°C.

24. The decoupled combustion method according to claim 11, characterized in that: The air in step (3) is introduced from the burnout air vents provided on the furnace wall.

25. The decoupled combustion method according to claim 11, characterized in that: The excess air coefficient during combustion after air is introduced in step (3) is 1.05 to 2.

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