CN111765475A - Grate-based circulating fluidized bed waste incineration boiler and its working method - Google Patents

Abstract

The invention discloses a grate-based circulating fluidized bed waste incineration boiler and a working method thereof, which belong to the technical field of domestic waste incineration flue gas treatment. The feeding system is connected with the grate drying section, the grate drying section, the fluidized combustion section and the grate burnout section are connected in sequence, and the lower part is connected with the primary air system through the air volume adjustment device respectively; the grate burnout section is connected with the slag discharge pipe Connection; the front arch of the grate is located above the drying section of the grate, and the rear arch of the grate is located above the burn-out section of the grate; the furnace is connected to the secondary air system, the top of the furnace is connected to the horizontal flue, and the horizontal flue is connected to the inlet of the return system Connection, the return material outlet of the material return system is connected with the material return port of the boiler through the material return pipe, and the flue gas outlet of the material return system is connected to the tail flue. The stability of feeding and slagging is improved, so that the combustion is uniform and stable, the emission of harmful pollutants is reduced, the combustion efficiency of the boiler is improved, and the risk of furnace shutdown is avoided.

Description

Grate-based circulating fluidized bed waste incineration boiler and its working method

technical field

The invention belongs to the technical field of domestic waste incineration flue gas treatment, and in particular relates to a grate-based circulating fluidized bed waste incineration boiler and a working method thereof.

Background technique

A large number of garbage and solid waste have brought great harm to the environment, mainly manifested as land occupation and pollution of air, soil and water bodies. Compared with landfill and compost, the incineration method has the characteristics of volume reduction, weight reduction, on-site treatment, fast treatment speed, heat recovery, and high degree of harmlessness. Therefore, various countries have taken waste incineration power generation as an important way to develop new energy and waste disposal.

Under the urgent need for the technology of harmless waste disposal, and the general trend of national environmental protection and energy saving, the waste incineration industry is facing challenges in technology, energy consumption, environmental protection and other aspects. At present, the main waste incineration systems on the market are fluidized bed and grate boilers. The biggest advantage of the grate furnace is that the operation is stable and reliable, and the amount of fly ash is small. Most of the solid waste can be directly burned into the furnace without any pretreatment. However, at present, there are still high investment costs for equipment, large floor space, unstable temperature distribution and combustion conditions on the grate and the furnace above it, low burnout rate, NOx generation and original emission concentration of dioxins and other pollutants. Too high, the tail flue gas environmental protection equipment is complex, and the operating cost is high. In contrast, fluidized bed waste incineration technology can effectively deal with these problems. The fluidized bed garbage furnace has strong adaptability to fuel types, can provide a large amount of heat required for garbage drying, pyrolysis and combustion, and has high combustion efficiency. At the same time, its flue gas emission performance is good, because the circulating fluidized bed adopts low temperature and staged combustion, which limits the formation of thermal and fuel-type NOx. Secondly, SNCR, furnace dry system and deacidification system are simple, efficient and reliable. If the conventional pollutant indicators of the waste incineration plant are further reduced, compared with the grate furnace, the fluidized bed waste furnace will have great advantages in the investment and operation cost of removing pollutants such as NOx, SO ₂ and HCl. However, there are still some problems in the fluidized bed waste furnace itself, such as the high proportion of ash, unstable combustion and high CO emissions, which still require further research.

SUMMARY OF THE INVENTION

In order to solve the above-mentioned defects in the prior art, the purpose of the present invention is to provide a grate-based circulating fluidized bed waste incineration boiler and its working method, which improves the stability of feeding and slag discharge, thereby making the combustion even , stable, reduce the emission of harmful pollutants, improve the combustion efficiency of the boiler, and avoid the risk of shutdown.

The present invention realizes through the following technical solutions:

The invention discloses a grate-based circulating fluidized bed waste incineration boiler, comprising a primary air system, a feeding system, a grate drying section, a fluidized combustion section, a grate burnout section, a grate front arch, a grate Back arch, slag discharge pipe, furnace, return pipe, secondary air system, horizontal flue and return system;

The feeding system is connected with the head end of the grate drying section, the tail end of the grate drying section is connected with the head end of the fluidized combustion section, the tail end of the fluidized combustion section is connected with the head end of the grate burnout section, and the grate The tail end of the burn-out section is connected with the slag discharge pipe; the lower parts of the grate drying section, the fluidized combustion section and the grate burn-out section are respectively connected to the primary air system through the air volume adjustment device, and the fluidized combustion section is used to realize the removal of waste materials. Fluidized combustion; the front arch of the grate is located above the drying section of the grate, and the rear arch of the grate is located above the burn-out section of the grate; the furnace is connected to the secondary air system, the top of the furnace is connected to the horizontal flue, and the horizontal flue is connected to the material return system The inlet of the material return system is connected to the material return port of the boiler through the material return pipe, and the flue gas outlet of the material return system is connected to the tail flue.

Preferably, the space between the grate drying section and the grate front arch gradually expands from the head end to the tail end of the grate drying section; The end to the beginning gradually expands.

Further preferably, the angle between the drying section of the grate and the front arch of the grate is 25-40°, and the angle between the burn-out section of the grate and the rear arch of the grate is 25-40°.

Preferably, the feeding system includes a feeding grab and a horizontal reciprocating feeding device, the feeding grab is arranged above the horizontal reciprocating feeding device, and the horizontal reciprocating feeding device is connected with the grate drying section.

Preferably, the fluidized combustion section is of the grate type or the fixed hood type.

Preferably, the secondary air system includes a first secondary air duct and a second secondary air duct, and the first secondary air duct and the second secondary air duct are respectively provided on both sides of the furnace.

Preferably, the material return system includes a separator, an outlet flue and an external bed heat exchanger; the central tube of the separator is connected to the outlet flue, and the outlet flue is connected to the tail flue; the inlet of the separator is connected to the horizontal flue, and the separation The outlet at the bottom of the boiler is connected with the external bed heat exchanger, and the external bed heat exchanger is connected with the material return port of the boiler through the material return pipe.

Preferably, the material return port of the boiler is set above the burnout section of the grate.

The invention discloses a working method of the above-mentioned grate-based circulating fluidized bed waste incineration boiler, including:

The waste material is fed into the furnace through the feeding system, and passes through the grate drying section, the fluidized combustion section and the grate burnout section in turn. The primary air system acts on the grate drying section, fluidized combustion section and grate through the air volume adjustment device In the burnout section, the waste material is dried and preheated in the grate drying section for fluidized combustion in the fluidized combustion section. The secondary air system enters the furnace to support combustion, and the dust-laden flue gas enters the return material system through the horizontal flue during the combustion process. After treatment, the flue gas enters the tail flue from the flue gas outlet, and the returned material is returned to the burn-out section of the grate from the return pipe to promote the burning of the garbage fuel and then discharged from the slag discharge pipe.

Preferably, the primary air volume in the grate drying section is 10% to 15% of the total primary air volume, the primary air volume in the fluidized combustion section is 75% to 80% of the total primary air volume, and the primary air volume in the grate burnout section is 5% to 10% of the total air volume of the primary air.

Compared with the prior art, the present invention has the following beneficial technical effects:

Due to the nature of the waste fuel, the existing fluidized bed domestic waste boilers are prone to problems such as unstable feeding and slagging. is a shutdown risk. The grate-based circulating fluidized bed waste incineration boiler of the present invention utilizes the advantages of the grate in the feeding and slagging system. Under the action of the grate, the grate can better realize the transportation and slag discharge of the domestic waste fuel. At the same time, the fluidized combustion is realized by adjusting the air volume of the fluidized combustion section. The form of the fluidized bed furnace and the capture of large particles by the return material system greatly improve the uniformity of the overall furnace temperature and prolong the residence time of fuel. Conducive to the full combustion of fuel and improve boiler efficiency.

At the environmental level, the uniformity of the overall temperature of the furnace and the residence time are very important for the formation of dioxins. Generally PCDD/Fs (dioxins) are formed by two mechanisms. One comes from a homogeneous reaction with a temperature range of 500-800°C. The main process is the rearrangement of chlorinated precursors to reactive gases such as chlorophenol (CP) and chlorobenzene (CBz). The PCDD/Fs in this process are called homogeneous PCDD/Fs or high temperature PCDD/Fs. PCDD/Fs can also be formed by a heterogeneous reaction at a temperature ranging from 200 to 400 °C. Heterogeneous reactions are mainly formed by CP, CBz, or carbon in fly ash under the catalytic action of fly ash, that is, de novoprocess (source generation). For different dioxin generation mechanisms, high temperature environment can achieve complete decomposition and destruction of dioxin and its precursors, so as to achieve the purpose of reducing dioxin. At present, the widely used 3T (temperature, time, turbulence) + E (excess air coefficient) control technology mainly refers to the furnace to reach 850 ° C, 2s or more severe processing conditions. In terms of turbulence intensity, the product of the geometric size of the high temperature zone of the fluidized bed and the flow velocity of the flue is larger than that of the grate furnace, so the turbulence is more intense. In addition, for the coupling of temperature and residence time, the combustion method of the fluidized bed also has its advantages, because it is chamber combustion and relies on high-concentration materials for heat and mass transfer, the furnace temperature is more adjustable, and the overall uniformity is better. Well, it is easy to get a higher temperature, which is more conducive to the decomposition of dioxin and its precursors. The more uniform the furnace temperature and the longer the residence time in the high temperature area, the decomposition rate of dioxin will be significantly improved. To sum up, in the present invention, the grate is used to transport and slag the fuel, and the fluidized combustion is carried out through the fluidized bed furnace and the material returning system, so that the furnace temperature can be uniform. At the same time, the uniform high temperature environment and long residence time in the fluidized bed boiler can ensure the decomposition of dioxin and its precursors. Under the premise of not adding activated carbon adsorption device at the tail, the dioxin emission under different loads of domestic waste incineration can be achieved.

Further, the space between the grate drying section and the front arch of the grate gradually expands from the head end to the tail end of the grate drying section; The tail end to the head end gradually expands to form a combustion space with a triangular-like cross-section, which has good heat preservation effect and can make the flue gas generated by combustion enter the furnace smoothly.

Furthermore, the included angle between the grate drying section and the grate front arch is 25° to 40°. Compared with the traditional structure, the heights of the grate front arch 9 and the grate rear arch 10 are reduced, and the grate burns out. The angle between the section and the back arch of the grate is 25-40°, which can effectively improve the gathering effect of the flue gas.

Further, the horizontal reciprocating feeding device is used for feeding, which is efficient and stable, and the feeding speed is controllable.

Further, the fluidized combustion section adopts the grate type, which is easy to realize the fluidized air distribution and has a good conveying and slagging effect; Improve the fluidization effect and further improve the combustion efficiency.

Further, the material return system adopts the combination of the separator and the external bed heat exchanger, and the high temperature superheater in the external bed heat exchanger can solve the problem of insufficient heating surface in the furnace. At the same time, because most of the corrosive atmosphere and coking-prone elements exist in the form of gas phase and sub-micron particles, they will not be trapped by the separator and then enter the external bed. Therefore, the use of an external bed heat exchanger can well solve the high temperature corrosion and coking problems of flue gas in the process of domestic waste incineration.

Further, the material return port of the boiler is set above the burnout section of the grate, which further promotes the burnout of unburned waste materials.

The working method of the grate-based circulating fluidized bed waste incineration boiler of the present invention improves the stability of feeding and slag discharge, thereby making the combustion uniform and stable, reducing the emission of harmful pollutants, and improving the combustion efficiency of the boiler , avoids the risk of shutdown, and has a good application prospect.

Further, the primary air volume of the grate drying section is 10% to 15% of the total primary air volume, which mainly plays the role of cooling the grate and preheating and drying waste materials; the primary air volume of the fluidized combustion section is the total primary air volume. 75% to 80% of the air volume is used to realize the fluidized combustion of waste materials; the primary air volume in the burnout section of the grate is 5% to 10% of the total primary air volume to ensure that the waste materials are burnt out.

Description of drawings

1 is a schematic diagram of the overall structure of Embodiment 1 of the present invention;

Fig. 2 is the top view of the internal structure of the grate-based circulating fluidized bed waste incineration boiler of the present invention;

FIG. 3 is a schematic diagram of the overall structure of Embodiment 2 of the present invention.

In the figure: 1- The air volume adjustment device of the grate drying section, 2- The air volume adjustment device of the fluidized combustion section, 3- The air volume adjustment device of the grate burnout section, 4- The grate drying section, 5- The fluidized combustion section, 6- Grate burnout section, 7-feeding grab bucket, 8-horizontal reciprocating feeding device, 9-grate front arch, 10-grate rear arch, 11-slagging pipe, 12-furnace, 13-return pipe, 14-first secondary air duct, 15-second secondary air duct, 16-horizontal flue, 17-separator, 17-1-first separator, 17-2-second separator, 18 - Outlet flue, 19 - External bed heat exchanger.

Detailed ways

The present invention is described in further detail below in conjunction with the accompanying drawings and specific embodiments, and its content is to explain rather than limit the present invention:

Example 1

A grate-based circulating fluidized bed waste incineration boiler of the present invention is shown in Figure 1. In this embodiment, the feeding system adopts a combination of a feeding grab 7 and a horizontal reciprocating feeding device 8. The bucket 7 is arranged above the horizontal reciprocating feeding device 8, the horizontal reciprocating feeding device 8 is connected with the head end of the grate drying section 4, and the tail end of the grate drying section 4 is connected with the head end of the fluidized combustion section 5, The tail end of the fluidized combustion section 5 is connected to the head end of the grate burnout section 6, the tail end of the grate burnout section 6 is connected to the slag discharge pipe 11, and the fluidized combustion section 5 is connected to the grate drying section 4 and the furnace. The exhaust burnout section 6 has the same grate form.

The lower parts of the grate drying section 4, the fluidized combustion section 5 and the grate burnout section 6 are connected with the grate drying section air volume adjustment device 1, the fluidized combustion section air volume adjustment device 2 and the grate burnout section air volume adjustment device 3 respectively. The primary air system is connected, and the fluidized combustion section 5 is used to realize fluidized combustion of waste materials.

The grate front arch 9 is located above the grate drying section 4, and the grate rear arch 10 is located above the grate burnout section 6; the space between the grate drying section 4 and the grate front arch 9 is along the head end of the grate drying section 4 It gradually expands to the tail end; the space between the grate burnout section 6 and the grate rear arch 10 gradually expands along the tail end of the grate burnout section 6 to the head end. Specifically, the angle between the drying section of the grate and the front arch of the grate can be set to 25-40°, and the angle between the burn-out section of the grate and the rear arch of the grate can be set to 25-40°, which is different from traditional grate arches. Compared with the structure, the structure reduces the height of the grate front arch 9 and the grate rear arch 10, and enhances the gathering effect of the flue gas while maintaining heat preservation.

The furnace chamber 12 is connected to the secondary air system, and the secondary air system includes a first secondary air duct 14 and a second secondary air duct 15, and the first secondary air duct 14 and the second secondary air duct 15 are respectively arranged in the furnace chamber 12 On both sides; the top of the furnace 12 is connected with the horizontal flue (16), and the horizontal flue 16 is connected with the inlet of the return material system, which includes a separator 17, an outlet flue 18 and an external bed heat exchanger 19; The central tube is connected to the outlet flue 18, and the outlet flue 18 is connected to the tail flue; the inlet of the separator 13 is connected to the horizontal flue 16, the outlet below the separator 13 is connected to the external bed heat exchanger 19, and the external bed heat exchanger 19 The material return pipe 13 is connected with the material return port of the boiler, preferably, the material return port of the boiler is set above the burnout section 6 of the grate.

Example 2

3, in this embodiment, the feeding system adopts the combination of the feeding grab 7 and the horizontal reciprocating feeding device 8. The feeding grab 7 is set above the horizontal reciprocating feeding device 8, and the horizontal reciprocating feeding The feeding device 8 is connected with the head end of the grate drying section 4, the tail end of the grate drying section 4 is connected with the head end of the fluidized combustion section 5, and the tail end of the fluidized combustion section 5 is connected with the head end of the grate burnout section 6. The tail end of the grate burnout section 6 is connected to the slag discharge pipe 11. The fluidized combustion section 5 adopts a fixed air cap type, and several fixed air caps are set on the air distribution plate to better control the flow rate of the local small holes. At the same time, the fluidized combustion of the material is realized.

The lower parts of the grate drying section 4, the fluidized combustion section 5 and the grate burnout section 6 are connected with the grate drying section air volume adjustment device 1, the fluidized combustion section air volume adjustment device 2 and the grate burnout section air volume adjustment device 3 respectively. The primary air system is connected, and the fluidized combustion section 5 is used to realize fluidized combustion of waste materials.

The grate front arch 9 is located above the grate drying section 4, and the grate rear arch 10 is located above the grate burnout section 6; the space between the grate drying section 4 and the grate front arch 9 is along the head end of the grate drying section 4 It gradually expands to the tail end; the space between the grate burnout section 6 and the grate rear arch 10 gradually expands along the tail end of the grate burnout section 6 to the head end. Specifically, the angle between the drying section of the grate and the front arch of the grate can be set to 25-40°, and the angle between the burn-out section of the grate and the rear arch of the grate can be set to 25-40°, which is different from traditional grate arches. Compared with the structure, the structure reduces the height of the grate front arch 9 and the grate rear arch 10, and enhances the gathering effect of the flue gas while maintaining heat preservation.

The furnace chamber 12 is connected to the secondary air system, and the secondary air system includes a first secondary air duct 14 and a second secondary air duct 15, and the first secondary air duct 14 and the second secondary air duct 15 are respectively arranged in the furnace chamber 12 On both sides; the top of the furnace 12 is connected with the horizontal flue (16), and the horizontal flue 16 is connected with the inlet of the material return system.

The material return system includes two sets of parallel separators 17, outlet flues 18 and external bed heat exchangers 19; the center cylinder of the separator is connected to the outlet flue 18, and the outlet flue 18 is connected to the tail flue; as shown in Figure 2, The inlets of the first separator 17-1 and the second separator 17-2 are respectively connected to a horizontal flue 16, and the outlets below the first separator 17-1 and the second separator 17-2 are respectively connected to an external bed The heat exchanger 19 is connected, and the external bed heat exchanger 19 is connected to the material return port of the boiler through the material return pipe 13. Preferably, the material return port of the boiler is set above the burnout section 6 of the grate.

Below in conjunction with the working method of embodiment 1, the present invention is further explained:

The domestic garbage is fed into the horizontal reciprocating feeding device 8 by the feeding grab 7, and the garbage fuel enters the grate under the action of its reciprocating push. The front grate arch 9 and the grate rear arch 10 of this furnace type are relatively low, which can allow the flue gas to enter the furnace chamber 12 while ensuring the heat preservation effect. The waste fuel passes through the grate drying section 4 , the fluidized combustion section 5 and the grate burnout section 6 in sequence under the transporting action of the grate. The primary air is controlled by the grate drying section air volume adjustment device 1, the fluidized combustion section air volume adjustment device 2 and the grate burnout section air volume adjustment device 3 to enter the grate drying section 4, fluidized combustion section 5 and grate burnout section respectively. 6 lower. In the actual operation process, the air volume of the grate drying section 4 accounts for 10% to 15% of the total air volume, the fluidized combustion section 5 air volume accounts for 75% to 80% of the total air volume, and the grate burnout section accounts for 5% to 10% of the total air volume. %. The air volume of the grate drying section 4 is small, which mainly plays the role of cooling and preheating the grate. Fluidized combustion section) air volume accounts for most of the primary air. Under the action of its separate fluidized combustion section air volume adjustment device 2, fluidized combustion of fuel can be achieved. During the combustion process, some small particles will follow the smoke. The gas enters the upper part of the furnace 12, and enters the first separator 17-1 and the second separator 17-2 through the horizontal flue 16. In the overall design process, since this type of grate mainly plays the role of material transportation and slag removal, the area of the grate is lower than that of a grate furnace of the same processing scale, and the specific design parameters are determined according to the characteristics of the garbage. After the dust-laden flue gas passes through the two separators 17, the large particles are captured by the separators 17 and then returned to the grate burnout section 6 through the lower external bed heat exchanger 19 through the return pipe 13, and then in the grate conveyance. It enters the slag discharge pipe 11 under operation. In order to ensure the complete decomposition of dioxins and their precursors, the furnace 12 can be properly designed with partial thermal insulation to ensure that the combustion temperature in the furnace is maintained at 950-1000°C. Here, the high temperature ash particles can further promote the burnout of unburned garbage fuel. The flue gas discharged from the central tube of the separator 17 is combined and discharged from the outlet flue 18 for tail heat exchange. The secondary air is passed into the furnace chamber 12 through the first secondary air duct 14 and the second secondary air duct 15 on the left and right sides for supplementary combustion to ensure fuel combustion efficiency.

It should be noted that the above is only one of the embodiments of the present invention, and equivalent changes made by the system described in the present invention are all included in the protection scope of the present invention. Those skilled in the art to which the present invention pertains can substitute the described specific examples in a similar manner, as long as they do not deviate from the structure of the present invention or go beyond the scope defined by the claims, they all belong to the protection scope of the present invention.

Claims (10)

1. A grate-based circulating fluidized bed waste incineration boiler is characterized in that, comprising primary air system, feeding system, grate drying section (4), fluidized combustion section (5), grate burn-out section (6), grate front arch (9), grate rear arch (10), slag discharge pipe (11), furnace chamber (12), material return pipe (13), secondary air system, horizontal flue (16) and return system; The feeding system is connected with the head end of the grate drying section (4), the tail end of the grate drying section (4) is connected with the head end of the fluidized combustion section (5), and the tail end of the fluidized combustion section (5) is connected with the head end of the fluidized combustion section (5). The head end of the grate burnout section (6) is connected, and the tail end of the grate burnout section (6) is connected with the slag discharge pipe (11); the grate drying section (4), the fluidized combustion section (5) and the furnace The lower part of the exhaust burnout section (6) is respectively connected with the primary air system through the air volume adjustment device, and the fluidized combustion section (5) is used to realize the fluidized combustion of the waste material; the grate front arch (9) is located in the grate drying section ( 4) Above, the grate rear arch (10) is located above the burnout section (6) of the grate; the furnace chamber (12) is connected to the secondary air system, and the top of the furnace chamber (12) is connected to the horizontal flue (16), which is connected to the horizontal flue. (16) Connect with the inlet of the material return system, the material return outlet of the material return system is connected with the material return port of the boiler through the material return pipe (13), and the flue gas outlet of the material return system is connected to the tail flue. 2. The grate-based circulating fluidized bed waste incineration boiler according to claim 1, wherein the space between the grate drying section (4) and the grate front arch (9) is along the grate drying section (4). 4) The head end to the tail end gradually expands; the space between the grate burnout section (6) and the grate rear arch (10) gradually expands along the tail end to the head end of the grate burnout section (6). 3. The grate-based circulating fluidized bed waste incineration boiler according to claim 2, wherein the angle between the grate drying section (4) and the grate front arch (9) is 25-40° , the angle between the grate burnout section (6) and the grate rear arch (10) is 25-40°. 4. The grate-based circulating fluidized bed waste incineration boiler according to claim 1, wherein the feeding system comprises a feeding grab (7) and a horizontal reciprocating feeding device (8), and the feeding grab The bucket (7) is arranged above the horizontal reciprocating feeding device (8), and the horizontal reciprocating feeding device (8) is connected with the grate drying section (4). 5 . The grate-based circulating fluidized bed waste incineration boiler according to claim 1 , wherein the fluidized combustion section ( 5 ) is a grate type or a fixed air cap type. 6 . 6. The grate-based circulating fluidized bed waste incineration boiler according to claim 1, wherein the secondary air system comprises a first secondary air duct (14) and a second secondary air duct (15), The first secondary air duct (14) and the second secondary air duct (15) are respectively arranged on both sides of the furnace (12). 7. The grate-based circulating fluidized bed waste incineration boiler according to claim 1, wherein the material return system comprises a separator (17), an outlet flue (18) and an external bed heat exchanger (19) ; The center cylinder of the separator is connected with the outlet flue (18), and the outlet flue (18) is connected to the tail flue; the inlet of the separator (17) is connected with the horizontal flue (16), and the outlet below the separator (17) is connected with The external bed heat exchanger (19) is connected, and the external bed heat exchanger (19) is connected with the material return port of the boiler through the material return pipe (13). 8 . The grate-based circulating fluidized bed waste incineration boiler according to claim 1 , wherein the material return port of the boiler is arranged above the grate burnout section ( 6 ). 9 . 9. The working method of any one of the grate-based circulating fluidized bed waste incineration boilers according to any one of claims 1 to 8, characterized in that, comprising: The waste material is fed into the furnace (12) through the feeding system, and passes through the grate drying section (4), the fluidized combustion section (5) and the grate burnout section (6) in sequence. The grate drying section (4), the fluidized combustion section (5) and the grate burn-out section (6), so that the waste material is dried and preheated in the grate drying section (4) and then processed in the fluidized combustion section (5). Fluidized combustion, the secondary air system enters the furnace (12) to assist combustion, and the dust-laden flue gas enters the material return system through the horizontal flue (16) during the combustion process. The return pipe (13) is returned to the burn-out section (6) of the grate to promote the burning of the waste fuel and then discharged from the slag discharge pipe (11). 10. The working method of the grate-based circulating fluidized bed waste incineration boiler according to claim 9, wherein the primary air volume of the grate drying section (4) is 10% to 15% of the total primary air volume, The primary air volume of the fluidized combustion section (5) is 75% to 80% of the total primary air volume, and the primary air volume of the grate burnout section (6) is 5% to 10% of the total primary air volume.

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