A coal-fired power plant co-processing agricultural and forestry waste blending system

Abstract

The utility model discloses a kind of coal-fired power plant collaborative processing forestry waste's blending combustion system, including the biomass pretreatment unit of sequentially connected, closed conveying unit, biomass coal powder mixing unit and coal-fired boiler unit;The utility model, adopt first cyclone separator and pulse dust collector combination purification, jointly cooperate and reduce the dust concentration of the gas stream containing biomass particle by gradient, cooperate with the design of the inclined flow guide hole of flame stabilizer, make high-temperature flue gas backflow, shorten its ignition time, make combustion flame stable, fine powder in fine powder bin is produced as fertilizer by-product, further increase biomass processing benefit, while avoid that boiler heating area ash corrosion;By grading pretreatment, crushing, drying, fine grinding and inert gas conveying, the technical problem that biomass fiber is easily entangled and easily deflagration is solved, and using power plant waste flue gas as heat source in drying process, effectively reduce the moisture content of biomass, while energy saving and consumption reduction are carried out.

Description

Technical Field

[0001] This utility model relates to the field of biomass combustion technology, and in particular to a co-firing system for co-processing agricultural and forestry waste in coal-fired power plants. Background Technology

[0002] Agricultural and forestry waste, as an important biomass resource, can be utilized for energy purposes, which can reduce fossil fuel consumption and solve the environmental pollution problem caused by open burning of straw. However, existing technologies have the following main drawbacks: Conventional crushing equipment is difficult to process agricultural and forestry waste with high fiber content, which can easily cause equipment blockage and entanglement; the drying process has high energy consumption and unstable moisture content control, which makes subsequent powdering difficult; Biomass dust has a low explosion limit, and traditional pneumatic conveying systems lack effective explosion-proof design, posing significant safety risks. When biomass is directly co-fired, the ignition temperature is high and the burnout rate is low, which can easily make the combustion flame unstable. In addition, the collection rate of fine biomass ash is low, which leads to ash corrosion on the boiler heating surface and makes it impossible to effectively utilize the fine ash. Therefore, it is necessary to design a co-firing system for the co-processing of agricultural and forestry waste in coal-fired power plants. Utility Model Content

[0003] The purpose of this invention is to provide a co-firing system for co-processing agricultural and forestry waste in coal-fired power plants. This system addresses the problems of existing conventional crushing equipment being unable to handle agricultural and forestry waste with high fiber content, easily causing equipment blockage and entanglement; high energy consumption and unstable moisture content control in the drying process, leading to difficulties in subsequent pulverization; low explosion limit of biomass dust; lack of effective explosion-proof design in traditional pneumatic conveying systems, posing significant safety risks; and high ignition temperature and low burnout rate of biomass during direct co-firing, which easily leads to unstable combustion flames and low capture rate of fine biomass ash, resulting in ash corrosion on the boiler heating surface and ineffective utilization of fine ash.

[0004] To solve the above-mentioned technical problems, this utility model provides the following technical solution: a co-firing system for co-processing agricultural and forestry waste in a coal-fired power plant, comprising a biomass pretreatment unit, a closed conveying unit, a biomass-coal powder mixing unit and a coal-fired boiler unit connected in sequence, wherein the biomass pretreatment unit includes a crusher, a first conveyor belt, a dryer, a second conveyor belt and a fine grinding mill; The crusher outlet is connected to the dryer inlet via a first conveyor belt, and the dryer outlet is connected to the fine grinding mill inlet via a second conveyor belt. After being crushed by the crusher, the biomass raw material is conveyed to the dryer via the first conveyor belt for drying. The dried biomass raw material is then conveyed to the fine grinding mill via the second conveyor belt for further processing into granules. The outlet of the fine grinding mill is connected to the inlet of the sealed conveying unit. The sealed conveying unit includes a gas pipeline and an inert gas inlet. Inert gas is conveyed to the gas pipeline through the inert gas inlet. Biomass pellets enter the gas pipeline from the fine grinding mill and are transported in the gas pipeline by inert gas pneumatic transport. The outlet of the closed conveying unit is connected to the biomass-coal powder mixing unit, which is a mixer. The mixer is equipped with a biomass inlet and a coal powder inlet. The biomass inlet is connected to the closed conveying unit. Biomass is received through the biomass inlet, and coal powder is received through the coal powder inlet. The biomass and coal powder are then mixed evenly in the mixer. The outlet of the biomass pulverized coal mixing unit is connected to a coal-fired boiler unit, which includes a burner, a flame stabilizer disposed at the outlet of the burner, and a furnace connected to the burner. The flame stabilizer has multiple inclined guide holes evenly distributed around its circumference. When the burner sprays a mixture of biomass and pulverized coal, the guide holes can cause the high-temperature flue gas to flow back, heating the newly injected biomass particles, shortening their ignition time, and stabilizing the combustion flame.

[0005] As a further technical solution of this utility model, the dryer is provided with a flue gas inlet channel, which is used to introduce low-temperature flue gas from the power plant, and to dry the biomass by utilizing the waste heat of the power plant's low-temperature flue gas, thereby removing moisture from the biomass while saving energy and reducing consumption.

[0006] As a further technical solution of this utility model, a first cyclone separator and a pulse dust collector are connected in series in the middle of the gas pipeline. The first cyclone separator is used to screen out large particles into the coarse powder bin, and the pulse dust collector is used to screen out fine particles into the fine powder bin. Together, they reduce the dust concentration of the airflow containing biomass particles in a gradient. The inlet of the first cyclone separator is connected to the outlet of the fine mill via a gas pipeline, the outlet of the first cyclone separator is connected to the inlet of the pulse dust collector, the bottom of the first cyclone separator is connected to a coarse powder bin, the bottom of the pulse dust collector is connected to a fine powder bin, and the fine powder in the fine powder bin is produced as a fertilizer by-product. The coarse powder silo is connected to the furnace via a return spray pipe.

[0007] As a further technical solution of this utility model, the return spray pipe is equipped with a spray gun, through which large biomass particles in the coarse powder bin are sprayed into the furnace for combustion.

[0008] As a further technical solution of this utility model, it also includes a flue gas port provided on the furnace, and a second cyclone separator is provided in the flue gas port. The second cyclone separator is used to separate the flue gas and fly ash in the flue gas. The flue gas is discharged into the subsequent processing equipment through the flue gas port, and the fly ash enters the furnace for re-combustion through the fly ash pipe.

[0009] As a further technical solution of this utility model, the bottom of the second cyclone separator is connected to a soot pipe inlet, and the soot pipe outlet is connected to the burner outlet.

[0010] As a further technical solution of this utility model, it also includes a magnetic separator installed on the first conveyor belt, which is used to remove iron from the crushed biomass raw materials.

[0011] The present invention provides a co-firing system for co-processing agricultural and forestry waste in coal-fired power plants, the advantages of which are: The system employs a combination of a first cyclone separator and a pulse dust collector for purification. Together, they work to reduce the dust concentration in the biomass particle-containing airflow in a gradient manner. In conjunction with the inclined guide hole design of the flame stabilizer, when the mixture of biomass and pulverized coal is sprayed from the burner, the high-temperature flue gas is recirculated to heat the newly injected biomass particles, shorten their ignition time, and stabilize the combustion flame. The fine powder in the fine powder bin is produced as a fertilizer by-product, further increasing the biomass treatment efficiency, while avoiding ash corrosion on the boiler heating surface. By employing graded pretreatment, crushing, drying, fine grinding, and inert gas conveying, the technical challenges of biomass fibers being prone to entanglement and explosive combustion have been solved. Furthermore, by using waste flue gas from power plants as a heat source in the drying process, the moisture content of biomass has been effectively reduced, while simultaneously saving energy and reducing consumption. Attached Figure Description

[0012] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0013] Figure 1 This is a schematic diagram of the overall structure of this utility model; Figure 2 for Figure 1 Enlarged view of the local structure of region A in the middle.

[0014] In the diagram: 1. Biomass pretreatment unit; 11. Crusher; 12. First conveyor belt; 121. Magnetic separator; 13. Dryer; 131. Flue gas inlet channel; 14. Second conveyor belt; 15. Fine grinding mill; 2. Closed conveying unit; 21. Gas pipeline; 211. First cyclone separator; 2111. Coarse powder bin; 2112. Back spray pipeline; 2113. Spray gun; 212. Pulse dust collector; 2121. Fine powder bin; 22. Inert gas inlet; 3. Biomass-coal powder mixing unit; 31. Mixer; 311. Biomass inlet; 312. Coal powder inlet; 4. Coal-fired boiler unit; 41. Burner; 42. Flame stabilizer; 421. Guide hole; 43. Furnace; 431. Flue gas outlet; 432. Second cyclone separator; 433. Ash pipeline. Detailed Implementation

[0015] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0016] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0017] Please see the appendix Figure 1 -Appendix Figure 2 The present invention provides an embodiment of a co-firing system for co-processing agricultural and forestry waste in a coal-fired power plant, comprising a biomass pretreatment unit 1, a closed conveying unit 2, a biomass-coal powder mixing unit 3, and a coal-fired boiler unit 4 connected in sequence. The biomass pretreatment unit 1 includes a crusher 11, a first conveyor belt 12, a dryer 13, a second conveyor belt 14, and a fine grinding mill 15. It also includes a magnetic separator 121 installed on the first conveyor belt 12, which is used to remove iron from the crushed biomass raw materials. The outlet of the crusher 11 is connected to the inlet of the dryer 13 via the first conveyor belt 12. The outlet of the dryer 13 is connected to the inlet of the fine grinding mill 15 via the second conveyor belt 14. After the biomass raw material is crushed by the crusher 11, it is conveyed to the dryer 13 by the first conveyor belt 12 for drying. The dryer 13 is provided with a flue gas inlet channel 131, which is used to introduce low-temperature flue gas from the power plant. The low-temperature flue gas is used for drying by utilizing the waste heat of the power plant, removing moisture from the biomass while saving energy and reducing consumption. The dried biomass raw material is conveyed to the fine grinding mill 15 via the second conveyor belt 14 for processing into granules. The outlet of the fine grinding mill 15 is connected to the inlet of the closed conveying unit 2. The closed conveying unit 2 includes a gas pipeline 21 and an inert gas inlet 22. Inert gas is conveyed to the gas pipeline 21 through the inert gas inlet 22. Biomass pellets enter the gas pipeline 21 from the fine grinding mill 15 and are pneumatically transported in the gas pipeline 21 by the inert gas. A first cyclone separator 211 and a pulse dust collector 212 are connected in series in the middle of the gas pipeline 21. The first cyclone separator 211 is used to screen out large particles to the coarse powder bin 2111, and the pulse dust collector 212 is used to screen out finer particles to the fine powder bin 2121. Together, they work to reduce the biomass pellet content in the gas. The dust concentration of the flow is as follows: the inlet of the first cyclone separator 211 is connected to the outlet of the fine mill 15 through the gas pipe 21, the outlet of the first cyclone separator 211 is connected to the inlet of the pulse dust collector 212, the bottom of the first cyclone separator 211 is connected to the coarse powder bin 2111, the coarse powder bin 2111 is connected to the furnace 43 through the return spray pipe 2112, the return spray pipe 2112 is equipped with a spray gun 2113, the large biomass particles in the coarse powder bin 2111 are sprayed into the furnace 43 for combustion through the spray gun 2113, the bottom of the pulse dust collector 212 is connected to the fine powder bin 2121, and the fine powder in the fine powder bin 2121 is produced as fertilizer by-product; The outlet of the closed conveying unit 2 is connected to the biomass-coal powder mixing unit 3, which is a mixer 31. The mixer 31 is equipped with a biomass inlet 311 and a coal powder inlet 312. The biomass inlet 311 is connected to the closed conveying unit 2. Biomass is received through the biomass inlet 311 and coal powder is received through the coal powder inlet 312. The biomass is then uniformly mixed in the mixer 31. The outlet of the biomass-coal powder mixing unit 3 is connected to a coal-fired boiler unit 4. The coal-fired boiler unit 4 includes a burner 41, a flame stabilizer 42 located at the outlet of the burner 41, and a furnace 43 connected to the burner 41. The flame stabilizer 42 has multiple inclined guide holes 421 evenly distributed around its circumference. When the mixture of biomass and coal powder is sprayed from the burner 41, the guide holes 421 can cause the high-temperature flue gas to flow back, heat the newly injected biomass particles, shorten their ignition time, and stabilize the combustion flame. It also includes a flue gas port 431 located on the furnace 43. A second cyclone separator 432 is installed in the flue gas port 431. The second cyclone separator 432 is used to separate the flue gas and fly ash in the flue gas. The flue gas is discharged into the subsequent treatment equipment through the flue gas port 431, and the fly ash enters the furnace 43 for re-combustion through the fly ash pipe 433. The bottom of the second cyclone separator 432 is connected to the inlet of the fly ash pipe 433, and the outlet of the fly ash pipe 433 is connected to the outlet of the burner 41.

[0018] Specifically, in use, firstly in the biomass pretreatment unit 1, agricultural and forestry waste is crushed by the crusher 11 and then transported to the dryer 13 by the first conveyor belt 12. It is dried by the low-temperature flue gas introduced through the flue gas inlet channel 131 and then sent to the fine grinder 15 for grinding by the second conveyor belt 14. In the closed conveying unit 2, nitrogen gas is introduced into the gas pipeline 21 through the inert gas inlet 22. The biomass powder is separated into coarse particles by the first cyclone separator 211 and stored in the coarse powder bin 2111. It is then burned by the return spray pipe 2112 and the fine particles are captured by the pulse dust collector 212 and stored in the fine powder bin 2121. The purified biomass powder enters the mixer 31 through the biomass inlet 311 and is mixed with the coal powder input through the coal powder inlet 312 in proportion. The mixed fuel is injected into the furnace 43 through the burner 41. The inclined guide hole 421 of the flame stabilizer 42 forms a high-temperature recirculation zone to promote combustion. After the flue gas in the furnace 43 is separated by the second cyclone separator 432, the soot is injected back through the soot pipe 433 to enhance combustion, thereby achieving efficient and clean utilization of biomass. In summary, this utility model uses a combination of a first cyclone separator 211 and a pulse dust collector 212 for purification. Together, they work to reduce the dust concentration in the biomass particle-containing airflow in a gradient manner. With the inclined guide hole 421 design of the flame stabilizer 42, when the mixture of biomass and coal powder is sprayed from the burner 41, the high-temperature flue gas is recirculated to heat the newly injected biomass particles, shorten their ignition time, and stabilize the combustion flame. The fine powder in the fine powder bin 2121 is produced as a fertilizer by-product, further increasing the biomass treatment efficiency, while avoiding ash corrosion on the boiler heating surface. By employing graded pretreatment, crushing, drying, fine grinding, and inert gas conveying, the technical challenges of biomass fibers being prone to entanglement and explosive combustion have been solved. Furthermore, by using waste flue gas from power plants as a heat source in the drying process, the moisture content of biomass has been effectively reduced, while simultaneously saving energy and reducing consumption.

[0019] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0020] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and not to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model.

Claims

1. A co-firing system for co-processing agricultural and forestry waste in a coal-fired power plant, comprising a biomass pretreatment unit (1), a closed conveying unit (2), a biomass-coal powder mixing unit (3), and a coal-fired boiler unit (4) connected in sequence, characterized in that: The biomass pretreatment unit (1) includes a crusher (11), a first conveyor belt (12), a dryer (13), a second conveyor belt (14), and a fine mill (15). The outlet of the crusher (11) is connected to the inlet of the dryer (13) via the first conveyor belt (12), and the outlet of the dryer (13) is connected to the inlet of the fine grinding mill (15) via the second conveyor belt (14). The outlet of the fine grinding mill (15) is connected to the inlet of the closed conveying unit (2). The closed conveying unit (2) includes a gas pipeline (21) and an inert gas inlet (22), through which inert gas is conveyed to the gas pipeline (21). The outlet of the closed conveying unit (2) is connected to the biomass coal powder mixing unit (3), which is a mixer (31). The mixer (31) is provided with a biomass inlet (311) and a coal powder inlet (312). The biomass inlet (311) is connected to the closed conveying unit (2). The outlet of the biomass coal powder mixing unit (3) is connected to a coal-fired boiler unit (4), which includes a burner (41), a flame stabilizer (42) installed at the outlet of the burner (41), and a furnace (43) connected to the burner (41). The flame stabilizer (42) has multiple inclined guide holes (421) evenly distributed around its circumference.

2. The co-firing system for co-processing agricultural and forestry waste in a coal-fired power plant according to claim 1, characterized in that: The dryer (13) is provided with a flue gas inlet channel (131), which is used to introduce low-temperature flue gas from the power plant.

3. The co-firing system for co-processing agricultural and forestry waste in a coal-fired power plant according to claim 1, characterized in that: The gas pipeline (21) is connected in series with a first cyclone separator (211) and a pulse dust collector (212) in the middle. The inlet of the first cyclone separator (211) is connected to the outlet of the fine grinding mill (15) through a gas pipe (21), the outlet of the first cyclone separator (211) is connected to the inlet of the pulse dust collector (212), the bottom of the first cyclone separator (211) is connected to a coarse powder bin (2111), and the bottom of the pulse dust collector (212) is connected to a fine powder bin (2121). The coarse powder silo (2111) is connected to the furnace (43) via a return spray pipe (2112).

4. The co-firing system for co-processing agricultural and forestry waste in a coal-fired power plant according to claim 3, characterized in that: The return spray pipe (2112) is equipped with a spray gun (2113).

5. The co-firing system for co-processing agricultural and forestry waste in a coal-fired power plant according to claim 1, characterized in that: It also includes a flue gas port (431) provided on the furnace (43), and a second cyclone separator (432) is provided in the flue gas port (431).

6. The co-firing system for co-processing agricultural and forestry waste in a coal-fired power plant according to claim 5, characterized in that: The bottom of the second cyclone separator (432) is connected to the inlet of the soot pipe (433), and the outlet of the soot pipe (433) is connected to the outlet of the burner (41).

7. The co-firing system for co-processing agricultural and forestry waste in a coal-fired power plant according to claim 1, characterized in that: It also includes a magnetic separator (121) installed on the first conveyor belt (12).

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