Biomass fuel pretreatment system for coal-fired power generation coupled with biomass fuel

Abstract

The present invention belongs to the technical field of coal-fired coupled biomass fuel power generation, and specifically relates to a biomass fuel pretreatment system for coal-fired coupled biomass fuel power generation. The off-site granulation process is eliminated, which facilitates the direct production of biomass fuel bulk materials into biomass fuel powder. The cyclone separation device and the dust removal device after the three-stage crushing device in the traditional process are eliminated, and the first pipeline connecting the discharge port of the three-stage crushing device and the feed port of the pneumatic conveying device is adjusted to negative pressure operation. The processing cost of biomass fuel is reduced, and the equipment utilization efficiency and the economy of system operation are improved. By setting up a drying device, the free water in the sorted biomass fuel secondary granular material is removed, the crushability of the biomass fuel is improved, and the energy consumption of the downstream three-stage crushing device and the pneumatic conveying device is reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of coal-fired coupled biomass fuel power generation, and in particular relates to a biomass fuel pretreatment system for coal-fired coupled biomass fuel power generation. Background Art

[0002] Common technologies for coupling biomass fuel with pulverized coal boilers for power generation include co-grinding, co-piping and independent combustion.

[0003] The co-grinding process premixes biomass fuel with coal upstream of the coal feeder, pulverizes the biomass fuel and coal together in a pulverizer, and then feeds the pulverized biomass fuel and coal mixture into a pulverized coal combustion unit. This process offers advantages such as a simple process and the absence of equipment modifications. However, the biomass fuel blending ratio is low, typically between 5 and 10%. This is due to factors such as the high moisture content of biomass fuel and the different grindability of biomass fuel and coal. When the biomass fuel blending ratio exceeds 5%, problems such as a significant decrease in pulverizer output, a high volatile content of biomass fuel, and the risk of spontaneous combustion are likely to occur.

[0004] The co-pipeline process involves processing biomass fuel in a dedicated biomass fuel hammer mill before injecting it into a pulverized coal pipeline or into a pulverized coal combustion unit. The biomass fuel blend ratio can be increased to over 20%. However, the co-pipeline process requires retrofitting existing equipment, resulting in complex piping and control systems and increased costs.

[0005] The independent combustion process involves individually pulverizing biomass fuel and injecting it into a dedicated biomass fuel combustion device in the boiler's main combustion zone. This process requires upgrading the existing boiler combustion device, resulting in a relatively high investment cost, but it can increase the biomass fuel blending ratio to 100%.

[0006] At present, all domestic coal-fired coupled biomass fuel power generation processes require the pretreatment of biomass fuel. The biomass fuel pretreatment system includes an off-site pelletizing process and an on-site crushing process. The off-site pelletizing process is mainly responsible for converting bulk biomass fuel into biomass fuel pellets, while the on-site crushing process is mainly responsible for converting biomass fuel pellets into biomass fuel powder. Specifically, the on-site crushing process includes an incoming unloading device, a screening device, a silo storage device, a primary crushing device, an intermediate storage device, a secondary crushing device, a tertiary crushing device, a cyclone separation device, a dust removal device, and a positive pressure pneumatic conveying device. The existing biomass fuel pretreatment system has problems such as many intermediate production links, large initial equipment investment, high energy consumption in the production of biomass fuel powder, and poor economic efficiency. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to provide a biomass fuel pretreatment system for coal-fired coupled biomass fuel power generation, which eliminates the off-site pelletizing process and facilitates direct conversion of biomass fuel bulk into biomass fuel powder.

[0008] The technical solution adopted by the present invention to solve the technical problem is: a biomass fuel pretreatment system for coal-fired coupled biomass fuel power generation, including a primary crushing device, a first conveying device, a secondary crushing device, a second conveying device, a sorting device, a sorting and unloading conveying mechanism, a drying device, a third conveying device, a three-stage crushing device, a pneumatic conveying device and a biomass fuel combustion device;

[0009] The first conveying device is used to convey the first-level biomass fuel particles from the discharge port of the first-level crushing device to the feed port of the second-level crushing device; the second conveying device is used to convey the second-level biomass fuel particles from the discharge port of the second-level crushing device to the feed port of the sorting device; the feed end of the sorting and unloading conveying mechanism is adjacent to and corresponding to the discharge port of the sorting device, and the discharge end of the sorting and unloading conveying mechanism is adjacent to and corresponding to the feed port of the drying device; the third conveying device is used to convey the sorted and dried second-level biomass fuel particles from the discharge port of the drying device to the feed port of the tertiary crushing device; the discharge port of the tertiary crushing device is connected to the feed port of the pneumatic conveying device through a first pipe, and the discharge port of the pneumatic conveying device is connected to the feed port of the biomass fuel combustion device through a second pipe.

[0010] Furthermore, the first conveying device includes a first belt conveying mechanism, a silo, a silo unloading conveying mechanism, and a second belt conveying mechanism;

[0011] The feed end of the first belt conveyor mechanism is adjacent to and corresponding to the discharge port of the primary crushing device, and the discharge end of the first belt conveyor mechanism is adjacent to and opposite to the feed port of the silo;

[0012] The silo unloading conveying mechanism and the second belt conveying mechanism are arranged in sequence along the material conveying direction L. The feed end of the silo unloading conveying mechanism is adjacent to and corresponding to the discharge port of the silo. The discharge end of the silo unloading conveying mechanism is adjacent to and corresponding to the feed end of the second belt conveying mechanism. The discharge end of the second belt conveying mechanism is adjacent to and corresponding to the feed port of the secondary crushing device.

[0013] Furthermore, it also includes a magnet device, which is arranged above the discharge end of the first belt conveyor mechanism.

[0014] Furthermore, the second conveying device includes a secondary crushing and unloading conveying mechanism and a lifting and conveying mechanism;

[0015] The feed end of the secondary crushing and discharging conveying mechanism is adjacent to and corresponding to the discharge port of the secondary crushing device, the discharge end of the secondary crushing and discharging conveying mechanism is adjacent to and corresponding to the lower feed port of the lifting and conveying mechanism, and the upper discharge port of the lifting and conveying mechanism is adjacent to and corresponding to the feed port of the sorting device.

[0016] Furthermore, the drying device includes a tank body and a heating mechanism provided on the side wall of the tank body;

[0017] The discharge end of the sorting and unloading conveying mechanism is adjacent to and corresponding to the feed port of the tank body.

[0018] Furthermore, the heating mechanism is a steam heating coil, and the steam heating coil is installed around the outer circumference of the tank body.

[0019] Furthermore, it also includes a drain pump, the inlet of the drain pump is connected to the inner cavity of the tank body through a drain pipe.

[0020] Furthermore, it also includes a pneumatic partition device; the second pipeline includes a first connecting pipe and a second connecting pipe that are connected to each other, the inlet end of the first connecting pipe is connected to the discharge port of the pneumatic conveying device, the outlet end of the first connecting pipe is connected to the inlet of the pneumatic partition device, the inlet end of the second connecting pipe is connected to the outlet of the pneumatic partition device, and the outlet end of the second connecting pipe is connected to the feed port of the biomass fuel combustion device.

[0021] Furthermore, it also includes a metering device, which is arranged on the third conveying device.

[0022] Furthermore, the sorting material discharge conveying mechanism, the silo material discharge conveying mechanism, the secondary crushing material discharge conveying mechanism and the lifting conveying mechanism are all screw conveyors.

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows: the present invention provides a biomass fuel pretreatment system for coal-fired coupled biomass fuel power generation, which eliminates the off-site granulation process and facilitates the direct conversion of bulk biomass fuel into biomass fuel powder. The cyclone separation device and the dust removal device after the three-stage crushing device in the traditional process are eliminated, and the first pipeline connecting the discharge port of the three-stage crushing device and the feed port of the pneumatic conveying device is adjusted to negative pressure operation. The processing cost of biomass fuel is reduced, and the efficiency of equipment use and the economy of system operation are improved. By providing a drying device, the free water in the sorted biomass fuel secondary granular material is removed, the crushability of the biomass fuel is improved, and the energy consumption of the downstream three-stage crushing device and the pneumatic conveying device is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a structural schematic diagram of the present invention;

[0025] Figure markings: 1-primary crushing device; 2-first belt conveyor mechanism; 3-magnet device; 4-silo; 5-silo unloading conveying mechanism; 6-second belt conveyor mechanism; 7-secondary crushing device; 8-secondary crushing unloading conveying mechanism; 9-lifting conveying mechanism; 10-sorting device; 11-sorting unloading conveying mechanism; 12-drying device; 1201-tank body; 1202-heating mechanism; 13-metering device; 14-third conveying device; 15-third-stage crushing device; 16-pneumatic conveying device; 17-pneumatic partition device; 18-biomass fuel combustion device; 19-drain pump; 20-air compressor; 21-boiler. DETAILED DESCRIPTION

[0026] The present invention will be further described below with reference to the accompanying drawings and examples.

[0027] The biomass fuel pretreatment system for coal-fired coupled biomass fuel power generation includes a primary crushing device 1, a first conveying device, a secondary crushing device 7, a second conveying device, a sorting device 10, a sorting and unloading conveying mechanism 11, a drying device 12, a third conveying device 14, a tertiary crushing device 15, a pneumatic conveying device 16 and a biomass fuel combustion device 18.

[0028] The first conveying device is used to convey the first-level biomass fuel particles from the discharge port of the first-level crushing device 1 to the feed port of the second-level crushing device 7; the second conveying device is used to convey the second-level biomass fuel particles from the discharge port of the second-level crushing device 7 to the feed port of the sorting device 10; the feed end of the sorting and unloading conveying mechanism 11 is adjacent to and corresponding to the discharge port of the sorting device 10, and the discharge end of the sorting and unloading conveying mechanism 11 is adjacent to and corresponding to the feed port of the drying device 12; the third conveying device 14 is used to convey the sorted and dried second-level biomass fuel particles from the discharge port of the drying device 12 to the feed port of the tertiary crushing device 15; the discharge port of the tertiary crushing device 15 is connected to the feed port of the pneumatic conveying device 16 through a first pipeline, and the discharge port of the pneumatic conveying device 16 is connected to the feed port of the biomass fuel combustion device 18 through a second pipeline.

[0029] The biomass fuel bulk material is fed into the primary crushing device 1 by a cantilever feeder. After being crushed by the primary crushing device 1, the biomass fuel bulk material forms a biomass fuel primary granular material. The particle size of the biomass fuel primary granular material is controlled within ≤100mm. The biomass fuel primary granular material is transported to the secondary crushing device 7 by a first conveying device. After being crushed by the secondary crushing device 7, the biomass fuel primary granular material forms a biomass fuel secondary granular material. The particle size of the biomass fuel secondary granular material is controlled within ≤30mm. The biomass fuel secondary granular material is transported to the sorting device 10 by a second conveying device. The sorting device 10 separates impurities such as sand and gravel from the biomass fuel secondary granular material. The sorting device 10 is a prior art, and specifically sucks away impurities such as sand and gravel from the biomass fuel secondary granular material through an air duct and a suction fan. The sorted biomass fuel secondary pellets are conveyed via the sorting and unloading conveying mechanism 11 to the drying device 12. The drying device 12 dries the sorted biomass fuel secondary pellets, reducing their moisture content to approximately 10%. At this point, the free water in the sorted biomass fuel secondary pellets has been substantially removed. The installation of the drying device 12 removes free water from the sorted biomass fuel secondary pellets, improving the biomass fuel's crushability and reducing the energy consumption of the downstream tertiary crushing device 15 and pneumatic conveying device 16. Furthermore, it reduces the latent heat loss of water vaporization after the coupled combustion of biomass fuel and pulverized coal, improving the economic efficiency of the system. The sorted and dried biomass fuel secondary pellets are conveyed via the third conveying device 14 to the tertiary crushing device 15. After crushing in the tertiary crushing device 15, the sorted and dried biomass fuel secondary pellets are formed into biomass fuel powder, with a particle size of ≤3 mm. Finally, the pneumatic conveying device 16 pumps the biomass fuel powder into the dedicated biomass fuel combustion device 18. The dedicated biomass fuel combustion device 18 extends into the boiler 21. Specifically, the first pipeline connecting the discharge port of the tertiary crushing device 15 and the feed port of the pneumatic conveying device 16 operates at negative pressure, while the second pipeline connecting the discharge port of the pneumatic conveying device 16 and the feed port of the biomass fuel combustion device 18 operates at positive pressure, facilitating smooth discharge of the tertiary crushing device 15.

[0030] The first conveying device may include only the first belt conveyor mechanism 2. Preferably, the first conveying device includes the first belt conveyor mechanism 2, a silo 4, a silo unloading conveyor mechanism 5, and a second belt conveyor mechanism 6. The feed end of the first belt conveyor mechanism 2 is adjacent to and corresponding to the discharge port of the primary crushing device 1, and the discharge end of the first belt conveyor mechanism 2 is adjacent to and opposite to the feed port of the silo 4. The silo unloading conveyor mechanism 5 and the second belt conveyor mechanism 6 are arranged sequentially along the material conveying direction L. The feed end of the silo unloading conveyor mechanism 5 is adjacent to and corresponding to the discharge port of the silo 4, and the discharge end of the silo unloading conveyor mechanism 5 is adjacent to and opposite to the feed end of the second belt conveyor mechanism 6. The discharge end of the second belt conveyor mechanism 6 is adjacent to and opposite to the feed port of the secondary crushing device 7. The silo 4 has a buffering function to facilitate uniform feeding of the secondary crushing device 7. The primary biomass fuel pellets are transported to the silo 4 through the first belt conveyor mechanism 2 , discharged from the discharge port of the silo 4 , and transported to the secondary crushing device 7 through the silo unloading conveyor mechanism 5 and the second belt conveyor mechanism 6 .

[0031] Preferably, the device further includes a magnet device 3, which is disposed above the discharge end of the first belt conveyor mechanism 2. When the primary biomass fuel pellets fall from the discharge end of the first belt conveyor mechanism 2 into the hopper 4, the magnet device 3 absorbs ferrous metal impurities in the primary biomass fuel pellets. Specifically, the magnet device 3 includes a bracket and a magnet block mounted on the bracket. The lower surface of the magnet block is located above the discharge end of the first belt conveyor mechanism 2.

[0032] The second conveying device may only include a secondary crushing and discharging conveying mechanism 8. Preferably, the second conveying device includes a secondary crushing and discharging conveying mechanism 8 and a lifting conveying mechanism 9; the feed end of the secondary crushing and discharging conveying mechanism 8 is adjacent to and corresponding to the discharge port of the secondary crushing device 7, the discharge end of the secondary crushing and discharging conveying mechanism 8 is adjacent to and corresponding to the lower feed port of the lifting conveying mechanism 9, and the upper discharge port of the lifting conveying mechanism 9 is adjacent to and corresponding to the feed port of the sorting device 10. The installation elevation of the secondary crushing device 7 can be lowered. The secondary particulate material of the biomass fuel is transported to the sorting device 10 through the secondary crushing and discharging conveying mechanism 8 and the lifting conveying mechanism 9.

[0033] Specifically, the drying device 12 includes a tank body 1201 and a heating mechanism 1202 disposed on the side wall of the tank body 1201. The discharge end of the sorting and unloading conveying mechanism 11 is adjacent to and corresponding to the feed inlet of the tank body 1201. The feed inlet of the tank body 1201 is also the feed inlet of the drying device 12.

[0034] The heating mechanism 1202 may be an electric heating tube. Preferably, the heating mechanism 1202 is a steam heating coil, which is wound and installed on the outer circumference of the tank body 1201. The steam entering the steam heating coil may come from the auxiliary steam system of the unit.

[0035] Preferably, a drain pump 19 is further included, the inlet of which is connected to the inner cavity of the tank body 1201 through a drain pipe. The drain generated after the biomass fuel secondary pellets are heated is recovered by the drain pump 19 to the unit drain system.

[0036] Preferably, a pneumatic isolation device 17 is further included; the second pipeline includes a first connecting pipe and a second connecting pipe, the inlet end of the first connecting pipe is connected to the discharge port of the pneumatic conveying device 16, the outlet end of the first connecting pipe is connected to the inlet of the pneumatic isolation device 17, the inlet end of the second connecting pipe is connected to the outlet of the pneumatic isolation device 17, and the outlet end of the second connecting pipe is connected to the feed port of the biomass fuel combustion device 18. The pneumatic isolation device 17 can effectively control the on-off of the second pipeline and is a prior art.

[0037] As a further preferred embodiment, the pneumatic isolation device 17 is a pneumatic gate valve. The pneumatic gate valve is a prior art.

[0038] When the first connecting pipe includes an upwardly extending climbing section, a through hole is provided in the first connecting pipe, located in the climbing section. Compressed air is passed upward through the through hole into the first connecting pipe, providing auxiliary power for the transportation of the biomass fuel powder. The compressed air is provided by an air compressor 20. Specifically, the compressed air outlet of the air compressor 20 is connected to the through hole via an air pipeline.

[0039] Preferably, a metering device 13 is further included, and the metering device 13 is provided on the third conveying device 14. The metering device 13 is a prior art. By providing the metering device 13, the amount of biomass fuel powder delivered to the biomass fuel combustion device 18 can be clearly known.

[0040] The metering device 13 can be an electronic belt scale. As a further preferred embodiment, the metering device 13 is a four-roller high-precision electronic belt scale. The four-roller high-precision electronic belt scale is a prior art.

[0041] Specifically, the sorting material discharge conveying mechanism 11, the silo material discharge conveying mechanism 5, the secondary crushing material discharge conveying mechanism 8 and the lifting conveying mechanism 9 are all screw conveyors.

[0042] As a further preferred embodiment, an air compressor 20 is further included, wherein the compressed air outlet of the air compressor 20 is connected to the second pipeline via a blowing pipe, and the connection between the blowing pipe and the second pipeline is located between the discharge port of the pneumatic conveying device 16 and the pneumatic partition device 17.

[0043] The embodiments of this specific implementation are all preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any equivalent changes made based on the structure, shape, and principle of the present invention should be included in the scope of protection of the present invention.

Claims

1. A biomass fuel pretreatment system for coal-fired coupled biomass fuel power generation, characterized in that: It comprises a primary crushing device (1), a first conveying device, a secondary crushing device (7), a second conveying device, a sorting device (10), a sorting and unloading conveying mechanism (11), a drying device (12), a third conveying device (14), a tertiary crushing device (15), a pneumatic conveying device (16), and a biomass fuel combustion device (18); The first conveying device is used to convey the first-level biomass fuel granules from the discharge port of the first-level crushing device (1) to the feed port of the second-level crushing device (7); the second conveying device is used to convey the second-level biomass fuel granules from the discharge port of the second-level crushing device (7) to the feed port of the sorting device (10); the feed end of the sorting discharge conveying mechanism (11) is adjacent to and corresponding to the discharge port of the sorting device (10), and the discharge end of the sorting discharge conveying mechanism (11) is adjacent to the drying device (10). The feed ports of the device (12) are adjacent and correspondingly arranged; the third conveying device (14) is used to convey the sorted and dried biomass fuel secondary granular material from the discharge port of the drying device (12) to the feed port of the third-stage crushing device (15); the discharge port of the third-stage crushing device (15) is connected to the feed port of the pneumatic conveying device (16) through a first pipe, and the discharge port of the pneumatic conveying device (16) is connected to the feed port of the biomass fuel combustion device (18) through a second pipe; The first conveying device comprises a first belt conveying mechanism (2), a silo (4), a silo unloading conveying mechanism (5), and a second belt conveying mechanism (6); The feed end of the first belt conveyor mechanism (2) is adjacent to and corresponding to the discharge port of the primary crushing device (1), and the discharge end of the first belt conveyor mechanism (2) is adjacent to and corresponding to the feed port of the silo (4); The silo unloading conveying mechanism (5) and the second belt conveying mechanism (6) are sequentially arranged along the material conveying direction L, the feed end of the silo unloading conveying mechanism (5) is adjacent to and corresponding to the discharge port of the silo (4), the discharge end of the silo unloading conveying mechanism (5) is adjacent to and corresponding to the feed end of the second belt conveying mechanism (6), and the discharge end of the second belt conveying mechanism (6) is adjacent to and corresponding to the feed port of the secondary crushing device (7); It also includes a magnet device (3), which is arranged above the discharge end of the first belt conveyor mechanism (2); The second conveying device comprises a secondary crushing and unloading conveying mechanism (8) and a lifting and conveying mechanism (9); The feed end of the secondary crushing and discharging conveying mechanism (8) is adjacent to and corresponding to the discharge port of the secondary crushing device (7), the discharge end of the secondary crushing and discharging conveying mechanism (8) is adjacent to and corresponding to the lower feed port of the lifting and conveying mechanism (9), and the upper discharge port of the lifting and conveying mechanism (9) is adjacent to and corresponding to the feed port of the sorting device (10).

2. The biomass fuel pretreatment system for coal-fired coupled biomass fuel power generation according to claim 1, characterized in that: The drying device (12) comprises a tank body (1201) and a heating mechanism (1202) arranged on a side wall of the tank body (1201); The discharge end of the sorting and unloading conveying mechanism (11) is adjacent to and corresponding to the feed port of the tank body (1201).

3. The biomass fuel pretreatment system for coal-fired coupled biomass fuel power generation according to claim 2, characterized in that: The heating mechanism (1202) is a steam-type heating coil, and the steam-type heating coil is wound and installed on the outer peripheral surface of the tank body (1201).

4. The biomass fuel pretreatment system for coal-fired coupled biomass fuel power generation according to claim 2, characterized in that: It also includes a drain pump (19), the inlet of the drain pump (19) being connected to the inner cavity of the tank body (1201) through a drain pipe.

5. The biomass fuel pretreatment system for coal-fired coupled biomass fuel power generation according to claim 1, characterized in that: It also includes a pneumatic isolation device (17); the second pipeline includes a first connecting pipe and a second connecting pipe that are connected to each other, the inlet end of the first connecting pipe is connected to the discharge port of the pneumatic conveying device (16), the outlet end of the first connecting pipe is connected to the inlet of the pneumatic isolation device (17), the inlet end of the second connecting pipe is connected to the outlet of the pneumatic isolation device (17), and the outlet end of the second connecting pipe is connected to the feed port of the biomass fuel combustion device (18).

6. The biomass fuel pretreatment system for coal-fired coupled biomass fuel power generation according to claim 1, characterized in that: It also includes a metering device (13), which is arranged on the third conveying device (14).

7. The biomass fuel pretreatment system for coal-fired coupled biomass fuel power generation according to claim 1, characterized in that: The sorting and unloading conveying mechanism (11), the silo unloading conveying mechanism (5), the secondary crushing and unloading conveying mechanism (8), and the lifting and conveying mechanism (9) are all screw conveyors.

Images