Smoke-steam combined auxiliary biomass roasting direct combustion system

Abstract

We provide a smoke-steam combined auxiliary biomass roasting direct combustion system. [Solution] The direct combustion system includes a biomass roasting system and a coal-fired thermal power generation unit, the coal-fired thermal power generation unit includes a boiler system 1 and a steam turbine system 2. The steam turbine system is used to supply steam to the biomass roasting system in order to provide roasting heat and maintain a constant roasting temperature. The boiler system is used to supply flue gas to the biomass roasting system in order to provide roasting heat and maintain the low-oxygen environment necessary for roasting. The biomass roasting system includes a steam heating outer cylinder and an inserted flue gas heating inner cylinder 10, and is used to heat the biomass fuel to the roasting temperature, continuously maintain the roasting temperature and roasting atmosphere, slowly move the biomass fuel forward, and discharge it outside the roasting system after the roasting time has been reached.

Description

Technical Field

[0001] The present invention belongs to the technical field of carbon emission reduction by direct combustion of biomass in a coal-fired power plant boiler, and specifically relates to a smoke-steam combined auxiliary type biomass roasting direct combustion system.

Background Art

[0002] Coal has always played the role of "ballast" in China's energy consumption. The transformation of the thermal power industry towards low carbonization has extremely important significance for the realization of the "double carbon" goal. The co-firing of coal-fired power units and low-carbon and zero-carbon energy, especially the co-firing of biomass fuels, is one of the main technologies for carbon emission reduction power generation in current coal-fired power units. In the "2021 Biomass Power Generation Project Construction Business Plan" announced by the China National Energy Administration, it is pointed out that biomass, as a solid fuel, coal-fired power enterprises should accelerate the flexible conversion on the fuel side by utilizing their existing advantages. In the "Coal-Fired Power Low-Carbonization Transformation Construction Action Plan (2024-2027)", it is clearly required that biomass co-firing be an important path in the low-carbonization transformation of coal-fired power units, and the model projects are required to have the ability to co-fire more than 10% of biomass fuel after transformation, significantly reducing coal consumption and carbon emission levels. From the perspective of national policies, the future transition of coal-fired power units towards low carbonization can be said to be an inevitable development direction.

[0003] The transition to low carbonization by co-firing coal-fired thermal power units and biomass zero-carbon fuels is a technology that highly conforms to China's national conditions. Currently, the co-firing of existing coal-fired thermal power units and biomass mainly includes three technical categories: direct co-firing, indirect co-firing, and parallel co-firing. Among them, the application of direct co-firing technology is the most extensive. This technology pulverizes biomass fuel into fine particles or powders, directly feeds it into the furnace of a coal-fired boiler, and co-fires it with coal to release energy.

[0004] However, due to characteristics such as the high moisture content and difficulty in crushing the fibrous structure of biomass fuels, the coal mill equipment in existing coal-fired power generation units is unsuitable for the crushing process of biomass fuels. Dedicated biomass crushing equipment has many problems, including low single-unit processing capacity, high energy consumption, and poor stability, which limits the widespread use of direct biomass combustion technology.

[0005] Biomass roasting technology is a thermochemical pretreatment technique that processes biomass fuel through gentle thermal decomposition, typically at 200-300°C in an inert or low-oxygen environment. This technology can significantly improve the energy density, hydrophobicity, and pulverizability of biomass, thereby increasing its applicability to fuel, power generation, or subsequent conversion processes (gasification, co-firing, etc.). Existing research results show that the properties of roasted biomass fuel are very similar to those of coal fuel. Therefore, roasted biomass fuel can be directly pulverized in the existing pulverized coal systems of existing coal-fired power generation units. Thus, roasting can be considered one of the most important technological routes for realizing co-firing of biomass with coal-fired power generation units.

[0006] Biomass roasting can proceed smoothly by requiring a relatively constant temperature and an inert or low-oxygen atmosphere, and the roasting process itself consumes a certain amount of energy. However, many of the system designs proposed in existing biomass roasting technologies use boiler flue gas extracted and used as the roasting medium. As the roasting process progresses, the temperature of the flue gas continuously decreases, requiring a relatively large flue gas flow rate, which can have a relatively significant impact on the normal operation of the boiler equipment. Alternatively, the temperature of the flue gas may not be suitable for the requirements of the roasting process, leading to a series of problems such as tar formation at high temperatures or ineffectiveness at low temperatures.

[0007] In light of the above problems, there is a need to provide a smoke-steam combined auxiliary biomass roasting direct combustion system that is rationally designed and effectively solves the above problems. [Overview of the project]

[0008] This invention aims to solve at least one of the technical problems present in related technologies and provides a smoke-steam combined auxiliary biomass roasting direct combustion system. One aspect of the present invention provides a smoke-steam combined auxiliary biomass roasting direct combustion system, the direct combustion system comprising a biomass roasting system and a coal-fired thermal power generation unit, wherein the coal-fired thermal power generation unit comprises a boiler system and a steam turbine system. The steam turbine system is used to supply steam to the biomass roasting system in order to provide roasting heat and maintain a constant roasting temperature. The boiler system is used to supply flue gas to the biomass roasting system in order to provide roasting heat and maintain the low-oxygen environment necessary for roasting. The biomass roasting system is used to heat the biomass fuel to a roasting temperature, continuously maintain the roasting temperature and roasting atmosphere, slowly move the biomass fuel forward, and discharge it outside the roasting system after the roasting time has been reached.

[0009] Optionally, the biomass roasting system includes a steam-heated outer cylinder and a flue gas-heated inner cylinder inserted inside the steam-heated outer cylinder. A supply port is provided on the high-temperature side of the flue gas-heated inner cylinder, where biomass fuel is supplied into the flue gas-heated inner cylinder through the supply port.

[0010] A steam inlet is provided on the high-temperature side of the steam heating outer cylinder, and a drain outlet is provided on the low-temperature side of the steam heating outer cylinder. Here, The steam inlet is connected to the steam side of the steam turbine system, and the drain outlet is connected to the drain side of the steam turbine system.

[0011] Selectively, a flue gas inlet is provided on the high-temperature side of the flue gas heating inner cylinder, and a flue gas and roasting gas outlet is provided on the low-temperature side of the flue gas heating inner cylinder. Herein, The flue gas inlet is connected to the flue of the boiler system, and the flue gas and roasting gas outlets are connected to the burner of the boiler system.

[0012] Optionally, the biomass roasting system further includes a screw conveyor. The screw conveyor is used to transport the biomass fuel from the high-temperature side of the flue gas heated inner cylinder to the low-temperature side of the flue gas heated inner cylinder.

[0013] Optionally, the direct combustion system further includes a roasting and cooling system.

[0014] The roasted material cooling system is used to cool the roasted biomass fuel to the same temperature as the original coal before sending it to the boiler system.

[0015] The roasting cooling system may optionally include a cooling fan and a heat exchanger.

[0016] The cooling fan is connected to the heat exchanger, and the cooling fan pressurizes the air before transporting it into the heat exchanger.

[0017] The inlet of the heat exchanger is connected to the outlet of the biomass roasting system, and the outlet of the heat exchanger is connected to the raw coal bunker of the boiler system. Here, the roasted biomass fuel is transported into the heat exchanger, cooled by heat exchange, and then transported to the boiler system.

[0018] Optionally, the air outlet of the heat exchanger is connected to the air preheater inlet of the boiler system. Here, the air in the heat exchanger comes into contact with the roasted material, undergoes heat exchange and is heated, before being transported to the air preheater inlet of the boiler system.

[0019] In the smoke-steam combined auxiliary biomass roasting direct combustion system of the present invention, the direct combustion system includes a biomass roasting system and a coal-fired thermal power generation unit, the coal-fired thermal power generation unit includes a boiler system and a steam turbine system. The steam turbine system is used to supply steam to the biomass roasting system in order to provide roasting heat and maintain a constant roasting temperature. The boiler system is used to supply flue gas to the biomass roasting system in order to provide roasting heat and maintain the low-oxygen environment necessary for roasting. The biomass roasting system is used to heat the biomass fuel to a roasting temperature, maintain the roasting temperature continuously, move the biomass fuel slowly forward, and discharge it outside the roasting system after the roasting time has been reached. By providing a biomass roasting system that utilizes dual auxiliary control using flue gas and steam from a coal-fired thermal power generation unit, it enables flexible co-firing of biomass roasting with direct combustion and coal-fired thermal power generation units. By utilizing the medium- and low-temperature flue gas and medium-pressure steam that the coal-fired thermal power generation unit possesses, it avoids the problem of supplying roasting heat by burning additional fuel, thereby achieving integrated energy utilization and saving energy. [Brief explanation of the drawing]

[0020] [Figure 1] A schematic diagram of the structure of a smoke-steam combined auxiliary biomass roasting direct combustion system according to one embodiment of the present invention. [Figure 2] This is a schematic flowchart illustrating the operation method of a smoke-steam combined auxiliary biomass roasting direct combustion system according to another embodiment of the present invention. [Modes for carrying out the invention]

[0021] To enable those skilled in the art to better understand the present invention, the present invention will be described in more detail below with reference to the drawings and specific embodiments.

[0022] As shown in Fig. 1, the present invention provides a combined smoke-steam assisted biomass roasting direct combustion system. The system includes a biomass roasting system and a coal-fired thermal power generation unit, and the coal-fired thermal power generation unit includes a boiler system 1 and a steam turbine system 2.

[0023] The steam turbine system 2 is used to supply steam to the biomass roasting system in order to provide roasting heat and maintain a certain roasting temperature. Specifically, steam with preset parameters is extracted from the steam turbine system 2 and enters the biomass roasting system. The pressure of the extracted steam is the steam pressure with the roasting temperature as the saturation temperature. The extracted steam maintains a relatively small degree of superheat, and if not, desuperheating water is used to lower the temperature. The extracted steam not only provides some roasting heat, but more importantly, plays a role in maintaining a certain roasting temperature level.

[0024] The boiler system 1 is used to supply flue gas to the biomass roasting system in order to provide roasting heat and maintain a low-oxygen environment required for roasting. Specifically, flue gas with predetermined parameters is extracted from the boiler system 1 and enters the roasting system. Here, the flue gas is collected from an appropriate position in the rear flue of the boiler, the flue gas temperature is set slightly higher than the roasting temperature, and the oxygen content in the flue gas does not exceed 6%. The extracted flue gas not only provides some roasting heat and discharges the roasting products, but more importantly, plays a role in maintaining the low-oxygen environment essential for roasting.

[0025] The biomass roasting system is used to heat the biomass fuel to the roasting temperature, continuously maintain the roasting temperature and roasting atmosphere environment, slowly move the biomass fuel forward, and discharge it outside the roasting system after reaching the roasting time. Here, the total energy supplied by boiler system 1 and steam turbine system 2 is correlated with the type, composition, processing amount, and roasting time of the biomass material. That is, the higher the degree of roasting, moisture content, and processing amount, the longer the required roasting time becomes, and the total energy increases accordingly. The reverse is also true. The heat required for the biomass roasting system is supplied simultaneously by both steam and flue gas from the coal-fired power generation unit, and the proportion of steam and flue gas in the roasting heat can be flexibly adjusted by adjusting the flow rate distribution between steam and flue gas.

[0026] The smoke-steam combined auxiliary biomass roasting direct combustion system of this invention provides a biomass roasting system that provides dual auxiliary control of the flue gas and steam of a coal-fired thermal power generation unit. By utilizing the characteristic that steam remains temperature constant during the condensation process, a constant temperature roasting system is constructed, and by utilizing the low oxygen properties of the flue gas, an inert roasting environment is constructed. Coordinated control of the steam and flue gas flow rates balances the effect of the roasting process on the normal operation of the original coal-fired thermal power generation unit. This enables flexible co-firing of biomass roasting direct combustion and the coal-fired thermal power generation unit, and by utilizing the medium-to-low temperature flue gas and medium-pressure steam that the coal-fired thermal power generation unit itself possesses, the problem of supplying roasting heat by burning additional fuel is avoided, resulting in integrated energy utilization and energy conservation.

[0027] For example, as shown in Figure 1, the biomass roasting system includes a steam-heated outer cylinder 7 and a flue gas-heated inner cylinder 10 inserted inside the steam-heated outer cylinder 7. A supply port 8 and an outlet port 9 are provided on the high-temperature side and low-temperature side of the flue gas heating inner cylinder 10, respectively, and biomass fuel is supplied into the flue gas heating inner cylinder 10 via the supply port 8. A steam inlet 5 is provided on the high-temperature side of the steam heating outer cylinder 7, and a drain outlet 6 is provided on the low-temperature side of the steam heating outer cylinder 7. Here, the steam inlet 5 is connected to the steam side of the steam turbine system 2, and the drain outlet 6 is connected to the drain side of the steam turbine system 2.

[0028] Specifically, the steam heating outer cylinder 7 has a fixed cylindrical structure. The steam heating outer cylinder 7 and the flue gas heating inner cylinder 10 form a sealed cylindrical structure, and together they constitute a partitioned heating cylinder. Steam from the steam turbine system 2 is supplied to the inside of the steam heating outer cylinder 7 via the steam inlet 5, and by performing phase transition heat exchange inside the steam heating outer cylinder 7, the cylinder temperature is maintained at a nearly constant level, achieving constant temperature roasting performance. The condensate after the phase transition flows out of the cylinder via the drain outlet 6, is returned to the steam turbine system 2 to recover residual heat, and enters the steam turbine system 2 for reuse.

[0029] In this embodiment, by using a structure in which a flue gas heating inner cylinder is inserted inside a steam heating outer cylinder, a heating environment maintained at a constant temperature necessary for biomass roasting is secured, and heating is achieved through direct contact between the flue gas and the material, improving heat transfer efficiency and roasting performance. Furthermore, by using steam from a coal-fired thermal power generation unit to provide heat for biomass roasting and maintain a constant temperature, the reuse of steam is realized, saving energy.

[0030] For example, as shown in Figure 1, a flue gas inlet 3 is provided on the high-temperature side of the flue gas heating inner cylinder 10, and a flue gas and roasting gas outlet 4 is provided on the low-temperature side of the flue gas heating inner cylinder 10. The flue gas inlet 3 is connected to the flue of the boiler system 1, and the flue gas and roasting gas outlet 4 is connected to the burner of the boiler system 1.

[0031] In this configuration, the flue gas heating inner cylinder 10 is a fixed cylindrical structure. Flue gas from the boiler system 1 is introduced into the flue gas heating inner cylinder 10 via the flue gas inlet 3. The flue gas flows slowly through the flue gas heating inner cylinder 10 to exchange heat and maintain a low-oxygen atmosphere during the roasting process. The mixture of flue gas and roasting gas generated in the roasting process is discharged from the system through the flue gas and roasting gas outlets 9 on the low-temperature side of the flue gas heating inner cylinder 10 and returned to the boiler system 1 for combustion. When the mixture of flue gas and roasting gas is introduced into the boiler system for combustion, a separate dedicated burner may be installed, or the mixed gas may be connected to the boiler's burner. The mixture of flue gas and roasting gas is introduced into the boiler system 1 for combustion. The combustion region of the mixed gas is the upper region of the main combustion region, which has a re-combustion effect and can reduce the generation of nitrogen oxides.

[0032] In this embodiment, by rationally connecting the flue gas inlet and outlet with the boiler system, the recirculation of flue gas is achieved, and the volatile gases generated during the roasting process are sent back to the boiler and burned, thereby reducing pollutant emissions and recovering energy.

[0033] Exemplary, as shown in Figure 1, the biomass roasting system further includes a screw conveyor 11. The screw conveyor 11 is used to transport biomass fuel from the high-temperature side of the flue gas heating inner cylinder 10 to the low-temperature side of the flue gas heating inner cylinder 10.

[0034] Specifically, the screw conveyor 11 is a screw-type propulsion mechanism that rotates along its own axis. Biomass fuel is supplied to the flue gas heated inner cylinder 10 and is slowly transported from the high-temperature side to the low-temperature side of the flue gas heated inner cylinder 10 by the feeding action of the screw conveyor 11. After the biomass material is supplied into the flue gas heated inner cylinder 10, it is rapidly heated to the roasting temperature by the flue gas and steam, and then the roasting process is completed at a constant temperature, and the material is discharged outside the flue gas heated inner cylinder 10 from the discharge port 9.

[0035] It should be explained that the conveying speed of the screw conveyor 11 is adjustable. Parameters such as the type, composition, and processing volume of biomass material are related to the theoretical roasting time, and by adjusting the rotation speed of the screw conveyor 11, the total time the material remains in the heated inner cylinder is controlled to be equal to or greater than the theoretical roasting time. The higher the degree of roasting of the material, the higher the moisture content, and the larger the processing volume, the longer the required theoretical roasting time becomes, and vice versa.

[0036] In this embodiment, a screw conveyor is used to achieve uniform material movement, resulting in a simple and reliable structure, easy control of the residence time of the material in the heated inner cylinder, and the ability to satisfy the roasting process requirements of different biomass raw materials.

[0037] For example, in this embodiment, the flue gas inlet / outlet, steam inlet / outlet, heating cylinder, etc., of the biomass roasting system are all fixed structures. There are no leaks, and it does not require drive by a high-capacity motor.

[0038] Exemplary, the direct combustion system further includes a roasted material cooling system. The roasted material cooling system is used to cool the roasted biomass fuel to the same temperature as the original coal before introducing it into the boiler system. This avoids the thermal shock that the high-temperature material would impose on the original coal system, thereby improving the safety and suitability of system operation.

[0039] For example, as shown in Figure 1, the roasting cooling system includes a cooling fan 12 and a heat exchanger 13. The cooling fan 12 is connected to the heat exchanger 13, and the cooling fan 12 pressurizes the air and then transports it into the heat exchanger 13. The inlet of the heat exchanger 13 is connected to the outlet 9 of the biomass roasting system, and the outlet of the heat exchanger 13 is connected to the raw coal bunker 14 of the boiler system 1. The roasted biomass fuel is transported into the heat exchanger 13, cooled by heat exchange, and then transported to the boiler system to avoid thermal shock from the high-temperature material to the original coal system.

[0040] The air outlet of the heat exchanger 13 is connected to the air preheater inlet of the boiler system 1. The air in the heat exchanger 13 comes into contact with the roasting material, undergoes heat exchange, and is heated before being transported to the air preheater inlet of the boiler system 1. The heated air is then reintroduced into the boiler system 1 for combustion, thereby recovering waste heat, improving boiler thermal efficiency, and realizing cascaded energy utilization within the system.

[0041] As shown in Figure 2, another aspect of the present invention provides an operating method S100 for a smoke-steam assisted direct combustion biomass roasting system. This method uses the smoke-steam assisted direct combustion biomass roasting system. The specific structural features of the smoke-steam assisted direct combustion biomass roasting system have already been described in detail above, so their description is omitted here.

[0042] The operating method S100 of the smoke-steam combined auxiliary biomass roasting direct combustion system of the present invention specifically includes the following steps. S110: In order to provide roasting heat and maintain a constant roasting temperature, steam is supplied to the biomass roasting system by the steam turbine system, and the steam undergoes condensation heat exchange in the steam heating outer cylinder. Specifically, steam from the steam turbine system 2 is introduced into the steam heating outer cylinder 7 via the steam inlet 5. The steam undergoes condensation heat exchange inside the steam heating outer cylinder 7, maintaining a nearly constant cylinder temperature and achieving constant-temperature roasting performance. The condensate after the phase transition is discharged outside the cylinder via the drain outlet 6, transported back to the steam turbine system 2 to recover residual heat, and then introduced back into the steam turbine system 2 for reuse.

[0043] S120: Flue gas is supplied to the biomass roasting system by the boiler system in order to provide roasting heat and maintain the low-oxygen environment necessary for roasting. Specifically, the flue gas flows slowly within the flue gas heating inner cylinder 10 to exchange heat and maintain the roasting process in a low-oxygen atmosphere. The mixture of flue gas and roasting gas generated in the roasting process is discharged outside the system from the flue gas and roasting gas outlet 9 on the low-temperature side of the flue gas heating inner cylinder 10, returned to the boiler system 1, and re-combusted.

[0044] S130: The biomass roasting system heats the biomass fuel to the roasting temperature, maintains the roasting temperature and roasting atmosphere continuously, moves the biomass fuel forward slowly, and discharges it out of the roasting system after the roasting time has been reached. Specifically, biomass fuel is supplied into the flue gas heated inner cylinder 10 and slowly transported from the high-temperature side to the low-temperature side of the flue gas heated inner cylinder 10 by the feeding action of the screw conveyor 11. After the biomass material is supplied into the flue gas heated inner cylinder 10, it is rapidly heated to the roasting temperature by flue gas and steam and the roasting temperature is continuously maintained. The roasting process is then completed in a constant temperature state, and after reaching the roasting time, it is discharged out of the flue gas heated inner cylinder 10 from the outlet 9 and returned to the boiler system 1 for re-combustion.

[0045] For example, the aforementioned driving method is: The system further includes a roasting and cooling system that cools the roasted biomass fuel to the same temperature as the original coal before sending it to the boiler system. Specifically, the cooling fan 12 pressurizes the air and then transports it into the heat exchanger 13. The roasted biomass fuel is transported into the heat exchanger 13, cooled by heat exchange, and then transported to the boiler system, thus avoiding thermal shock from the high-temperature material to the original coal system. The air in the heat exchanger 13 comes into contact with the roasted material, undergoes heat exchange, and is heated before being transported to the air preheater inlet of the boiler system 1. The heated air is then reintroduced into the boiler system 1 for combustion, recovering waste heat, improving boiler thermal efficiency, and realizing cascaded energy utilization within the system.

[0046] The operation method of the smoke-steam combined auxiliary biomass roasting direct combustion system of this invention utilizes the characteristic that steam remains temperature constant during the condensation process to construct a constant-temperature roasting system, utilizes the low-oxygen properties of flue gas to create an inert roasting environment, and balances the impact of the roasting process on the normal operation of the original coal-fired thermal power generation unit through coordinated control of steam and flue gas flow rates. This enables flexible co-firing of biomass roasting direct combustion and coal-fired thermal power generation units, avoids the problem of supplying roasting heat by burning additional fuel by utilizing the medium- and low-temperature flue gas and medium-pressure steam that the coal-fired thermal power generation unit itself possesses, realizes integrated energy utilization, and saves energy.

[0047] It should be understood that the embodiments described above are merely exemplary embodiments used to illustrate the principles of the present invention, and the present invention is not limited thereto. Those skilled in the art can make various modifications and improvements without departing from the spirit and substance of the present invention, and these modifications and improvements are also within the scope of the protection of the present invention.

Claims

1. A smoke-steam combined auxiliary biomass roasting direct combustion system, comprising a biomass roasting system and a coal-fired thermal power generation unit, wherein the coal-fired thermal power generation unit comprises a boiler system and a steam turbine system. The steam turbine system is used to supply steam to the biomass roasting system in order to provide roasting heat and maintain a constant roasting temperature. The boiler system is used to supply flue gas to the biomass roasting system in order to provide roasting heat and maintain the low-oxygen environment necessary for roasting. The aforementioned biomass roasting system is a smoke-steam combined auxiliary biomass direct combustion roasting system characterized by being used to heat biomass fuel to a roasting temperature, continuously maintain the roasting temperature and roasting atmosphere, slowly move the biomass fuel forward, and discharge it outside the roasting system after the roasting time has been reached.

2. The biomass roasting system includes a steam heating outer cylinder and a flue gas heating inner cylinder inserted inside the steam heating outer cylinder. A supply port is provided on the high-temperature side of the flue gas heating inner cylinder, and biomass fuel is supplied into the flue gas heating inner cylinder through the supply port. A steam inlet is provided on the high-temperature side of the steam heating outer cylinder, and a drain outlet is provided on the low-temperature side of the steam heating outer cylinder. The system according to claim 1, characterized in that the steam inlet is connected to the steam side of the steam turbine system, and the drain outlet is connected to the drain side of the steam turbine system.

3. A flue gas inlet is provided on the high-temperature side of the flue gas heating inner cylinder, and a flue gas and roasting gas outlet is provided on the low-temperature side of the flue gas heating inner cylinder. The system according to claim 2, characterized in that the flue gas inlet is connected to the flue of the boiler system, and the flue gas and roasting gas outlets are connected to the burner of the boiler system.

4. The biomass roasting system further includes a screw conveyor, The system according to claim 2, characterized in that the screw conveyor is used to transport biomass fuel from the high-temperature side of the flue gas heating inner cylinder to the low-temperature side of the flue gas heating inner cylinder.

5. The direct combustion system further includes a roasting and cooling system, The system according to any one of claims 1 to 4, characterized in that the roasted material cooling system is used to cool the roasted biomass fuel to the same temperature as the original coal before sending it to the boiler system.

6. The roasting cooling system includes a cooling fan and a heat exchanger. The cooling fan is connected to the heat exchanger, and the cooling fan pressurizes the air and then transports it into the heat exchanger. The system according to claim 5, characterized in that the inlet of the heat exchanger is connected to the outlet of the biomass roasting system, the outlet of the heat exchanger is connected to the raw coal bunker of the boiler system, and the roasted biomass fuel is transported into the heat exchanger, cooled by heat exchange, and then transported to the boiler system.

7. The system according to claim 6, characterized in that the air outlet of the heat exchanger is connected to the air preheater inlet of the boiler system, and the air inside the heat exchanger comes into contact with the roasted material, undergoes heat exchange and is heated, before being transported to the air preheater inlet of the boiler system.

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