Biomass coupling combustion system

Abstract

The biomass coupling combustion system comprises a coal-fired unit, the coal-fired unit comprises a coal boiler, a coal economizer, a low-temperature reheater, an absorption tower and a boiler deaerator, the coal boiler is provided with a first feeding structure, a first ash outlet and a first smoke outlet, and the coal economizer and the low-temperature reheater are arranged in the coal boiler; the absorption tower is communicated with the first flue gas outlet through a first flue gas pipeline; the biomass boiler is provided with a second feeding structure, a second ash outlet and a second flue gas outlet, the first ash outlet and the second ash outlet are relatively independent, and a water supply outlet of the boiler deaerator is communicated with a water inlet of the biomass boiler through a first water supply pipeline; the biomass power generation equipment comprises a biomass steam turbine, the biomass steam turbine communicates with a steam outlet of the biomass boiler through a first steam pipeline so that the biomass steam turbine can generate power through steam provided by the first steam pipeline, and a steam exhaust outlet of the biomass steam turbine communicates with the low-temperature reheater through a first steam exhaust pipeline.

Description

Technical Field

[0001] The present invention relates to the technical field of combustion equipment, and in particular to a biomass coupled combustion system. Background Art

[0002] Biomass co-combustion is the use of biomass resources such as agricultural and forestry waste, psammophytes, and energy plants to implement coal-fired power generation coupled with biomass. Currently, the main coupled combustion methods are the following two methods:

[0003] Direct-coupled combustion technology involves mixing biomass fuel with coal and burning them together in existing coal-fired boilers. This method fully utilizes existing facilities and has relatively low modification costs. The proportion of direct-coupled combustion can generally range from 5% to 20% or even higher, but the specific ratio is limited by factors such as biomass fuel pretreatment, boiler design, and operating conditions. Among them, the modification cost is relatively low, but it may cause wear and corrosion to existing coal-fired boiler equipment, especially when the biomass fuel contains a high content of alkali metals. The pretreatment and storage systems of biomass fuel may require major changes, which may increase the complexity of the system and operating costs. At the same time, the pretreatment system has certain requirements for fuel quality. Because the calorific value of biomass fuel is generally lower than that of coal, the operating parameters of the boiler may need to be adjusted, which may affect the power generation efficiency.

[0004] Indirect coupled combustion technology involves first gasifying or pyrolyzing the biomass in specialized equipment, and then feeding the resulting combustible gas into a coal-fired boiler for combustion. This method has the advantage of somewhat reducing the fouling and corrosion issues associated with direct combustion, but the system is more complex and the investment cost is higher. The combustion of biomass requires additional gasification equipment, which increases system complexity and cost. Tar and ash may be produced during the gasification process, requiring additional treatment systems to purify the gas, which increases operational complexity and cost. Gasification efficiency may be lower than direct combustion, thus potentially impacting overall energy conversion efficiency.

[0005] Therefore, how to realize biomass fuel and improve energy conversion efficiency and power generation efficiency is an urgent problem to be solved by people in this technical field. Summary of the Invention

[0006] In view of this, the present invention provides a biomass coupled combustion system to realize biomass fuel and improve energy conversion efficiency and power generation efficiency.

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] A biomass coupled combustion system, comprising:

[0009] A coal-fired unit comprising a coal boiler, an economizer, a low-temperature reheater, an absorption tower, and a boiler deaerator, wherein the coal boiler has a first feed structure, a first ash outlet, and a first flue gas outlet, the economizer and the low-temperature reheater are disposed within the coal boiler, and the absorption tower is connected to the first flue gas outlet via a first flue gas duct;

[0010] A biomass boiler having a second feeding structure, a second ash outlet, and a second flue gas outlet, wherein the first ash outlet and the second ash outlet are relatively independent, and the water feed outlet of the boiler deaerator is connected to the water inlet of the biomass boiler through a first water feed pipe;

[0011] Biomass power generation equipment, the biomass power generation equipment includes a biomass steam turbine, the biomass steam turbine is connected to the steam outlet of the biomass boiler through a first steam pipe, so that the biomass steam turbine uses the steam provided by the first steam pipe to generate electricity, and the exhaust outlet of the biomass steam turbine is connected to the low-temperature reheater through the first exhaust steam pipe.

[0012] Optionally, in the above-mentioned biomass coupled combustion system, the coal-fired unit further comprises a feedwater heater, the feedwater heater comprises a feedwater inlet pipe and a feedwater outlet pipe, and the outlet end of the feedwater outlet pipe is connected to the economizer;

[0013] The steam outlet of the biomass boiler has a steam main pipe and a second steam pipe, and the first steam pipe and the second steam pipe are connected to the outlet end of the steam main pipe;

[0014] The steam inlet of the feedwater heater is connected to the second steam pipe through the second steam inlet pipe, so that the steam entering the feedwater heater heats the feedwater in the feedwater heater, and the cooled steam is connected to the inlet of the first feedwater pipe through the second condensation outlet pipe.

[0015] Optionally, in the above-mentioned biomass coupled combustion system, the coal-fired unit further comprises a hot air heater, the hot air heater having an air inlet pipe and an air outlet pipe, and the outlet end of the air outlet pipe is connected to the coal boiler;

[0016] The steam inlet of the hot air heater is connected to the second steam pipe through the first steam inlet pipe, so that the steam entering the hot air heater heats the air flow in the hot air heater, and the cooled steam is connected to the second steam inlet pipe through the first steam outlet pipe.

[0017] Optionally, in the above biomass coupled combustion system, the outlet of the first steam outlet pipe is connected to the second steam inlet pipe;

[0018] The second steam pipeline is connected to the second steam inlet pipe via a first control pipeline;

[0019] The first control pipeline has a first control valve, the first steam inlet pipe has a second control valve, the first steam outlet pipe has a third control valve, and the first steam pipeline has a fourth control valve.

[0020] Optionally, in the above-mentioned biomass coupled combustion system, the water outlet of the boiler deaerator has a water outlet main pipe, the water outlet main pipe has a first water feed pump, and the inlet of the first water feed pipe is connected to the outlet of the water outlet main pipe;

[0021] The second condensate outlet pipe is provided with a second water supply pump, and the outlet of the second condensate outlet pipe is connected to the water outlet main pipe.

[0022] Optionally, in the above-mentioned biomass coupled combustion system, the coal-fired unit further comprises a coal-fired unit high-pressure cylinder, and the coal-fired unit high-pressure cylinder is connected to the reheat steam cold section pipeline of the low-temperature reheater;

[0023] The outlet of the first exhaust pipe is connected to the reheat steam cold section pipe, so that the steam flowing out of the outlet of the first exhaust pipe and the steam discharged from the high-pressure cylinder of the coal-fired unit are mixed in the reheat steam cold section pipe and flow into the low-temperature reheater.

[0024] Optionally, in the above-mentioned biomass coupled combustion system, the first feeding structure and the second feeding structure are relatively independent.

[0025] Optionally, in the above-mentioned biomass coupled combustion system, the second feeding structure includes a biomass feeder and a biomass conveyor;

[0026] The biomass conveyor communicates the outlet of the biomass feeder with the inlet of the biomass boiler.

[0027] Optionally, in the above-mentioned biomass coupled combustion system, the second flue gas outlet is connected to the absorption tower through a second flue gas duct.

[0028] Optionally, in the above biomass coupled combustion system, the outlet of the second flue gas duct is connected to the first flue gas duct.

[0029] As can be seen from the above technical solution, in the biomass coupled combustion system provided by the present invention, the water inlet of the biomass boiler is connected to the water feed outlet of the boiler deaerator of the coal-fired unit through the first water feed pipe, and the steam outlet of the biomass boiler is connected to the low-temperature reheater of the coal-fired unit through the first exhaust pipe through the biomass turbine of the biomass power generation equipment. The biomass boiler can enter the parallel-arranged biomass boiler through the feed water of the coal-fired unit (the feed water deoxygenated by the boiler deaerator), generate high-temperature, high-pressure steam, and enter the biomass power generation equipment including the biomass turbine to generate electricity. The exhaust steam is connected to the low-temperature reheater through the first exhaust pipe from the exhaust outlet of the biomass turbine, so that the exhaust steam enters the steam-water system of the coal-fired unit. Through the parallel design of the coal boiler and the biomass boiler, the biomass boiler in the biomass coupled combustion system provided by the embodiment of the present invention can burn the biomass fuel in a targeted manner, while the coal raw material is burned by the coal boiler. Through the above-mentioned setting, it can adapt to a wider range of biomass types and can adapt to a higher biomass blending ratio. Compared with the biomass direct-fired power plant (direct coupled combustion technology and indirect coupled combustion technology), it effectively improves the energy conversion efficiency and power generation efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0031] Figure 1 This is a schematic structural diagram of a biomass coupled combustion system provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0032] The invention discloses a biomass coupled combustion system to realize biomass fuel and improve energy conversion efficiency and power generation efficiency.

[0033] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0034] like Figure 1As shown, an embodiment of the present invention provides a biomass coupled combustion system, including a coal-fired unit, a biomass boiler 3-2 and a biomass power generation device. The coal-fired unit includes a coal boiler 6-2, an economizer 6-3, a low-temperature reheater 6-4, an absorption tower 6-7 and a boiler deaerator. The coal boiler 6-2 has a first feed structure, a first ash outlet and a first flue gas outlet. The economizer 6-3 and the low-temperature reheater 6-4 are arranged in the coal boiler 6-2. The absorption tower 6-7 is connected to the first flue gas outlet through the first flue gas pipe 6-6. The biomass boiler 3-2 has a second feed structure, a second ash outlet and a second flue gas outlet. The first ash outlet and the second ash outlet are relatively independent. The water outlet of the boiler deaerator is It is connected to the water inlet of the biomass boiler 3-2 through the first water supply pipe 1-2; the water supply outlet of the boiler deaerator is connected to the water inlet of the biomass boiler 3-2 through the first water supply pipe 1-2; the biomass power generation equipment includes a biomass steam turbine 3-4, and the biomass steam turbine 3-4 is connected to the steam outlet of the biomass boiler 3-2 through the first steam pipe 1-3, so that the biomass steam turbine 3-4 uses the steam provided by the first steam pipe 1-3 to generate electricity, and the exhaust outlet of the biomass steam turbine 3-4 is connected to the low-temperature reheater 6-4 through the first exhaust pipe 1-4.

[0035] In the biomass coupled combustion system provided by an embodiment of the present invention, the water inlet of the biomass boiler 3-2 is connected to the water feed outlet of the boiler deaerator of the coal-fired unit through the first water feed pipe 1-2, and the steam outlet of the biomass boiler 3-2 passes through the biomass turbine 3-4 of the biomass power generation equipment and is connected to the low-temperature reheater 6-4 of the coal-fired unit through the first exhaust pipe 1-4. The feed water of the coal-fired unit (the feed water deoxygenated by the boiler deaerator) can enter the parallel-arranged biomass boiler 3-2 to generate high-temperature, high-pressure steam that enters the biomass power generation equipment including the biomass turbine 3-4 to generate electricity. The exhaust steam is connected from the exhaust outlet of the biomass turbine 3-4 to the low-temperature reheater 6-4 through the first exhaust pipe 1-4, so that the exhaust steam enters the steam-water system of the coal-fired unit. Through the parallel design of the coal boiler 6-2 and the biomass boiler 3-2, the biomass boiler 3-2 in the biomass coupled combustion system provided by the embodiment of the present invention can burn the biomass fuel in a targeted manner, while the coal raw material is burned by the coal boiler 6-2. Through the above-mentioned setting, it can adapt to a wider range of biomass types and can adapt to a higher biomass blending ratio. Compared with the biomass direct-fired power plant (direct coupling combustion technology and indirect coupling combustion technology), it effectively improves the energy conversion efficiency and power generation efficiency.

[0036] That is, the biomass coupled combustion system provided in the embodiment of the present invention is different from direct coupled combustion technology and indirect coupled combustion technology. It can realize parallel combustion of the coal boiler 6-2 and the biomass boiler 3-2 in the coal-fired unit, making the biomass coupled combustion system provided in the embodiment of the present invention a biomass parallel coupled combustion system. Among them, a specially designed biomass combustion boiler can be used as the biomass boiler 3-2 to carry out targeted combustion of biomass raw materials, increasing the possibility of mixed combustion of biomass fuels that are difficult to use in coal-fired power plants. In addition, because the first ash outlet and the second ash outlet are relatively independent, the biomass ash and coal ash are discharged separately, making it easier to handle the ash separately.

[0037] In some embodiments, the coal-fired unit further includes a feedwater heater 4-4, which has a feedwater inlet pipe 2-1 and a feedwater outlet pipe 2-2, the outlet end of the feedwater outlet pipe 2-2 being connected to the economizer 6-3; the steam inlet of the feedwater heater 4-4 is connected to the second steam pipe 1-10 via the second steam inlet pipe 1-11, so that the steam entering the feedwater heater 4-4 heats the feedwater in the feedwater heater 4-4, and the cooled steam is connected to the inlet of the first feedwater pipe 1-2 via the second condenser outlet pipe 1-12. Through the above arrangement, the superheated steam generated by the biomass boiler 3-2 burning biomass raw materials is used to heat the feedwater entering the coal boiler 6-2, avoiding the need for additional heating equipment, simplifying the biomass coupled combustion system, avoiding the need for additional heat energy for heating the feedwater, and effectively saving energy.

[0038] The water inlet pipe 2-1 can be connected to the water outlet of the boiler deaerator, so that the boiler deaerator can supply water to the coal boiler 6-2 and the biomass boiler 3-2, thereby connecting the coal boiler 6-2 and the biomass boiler 3-2 in parallel along the water supply path. Of course, the water inlet pipe 2-1 can also be connected to another device (such as the outlet of the high-pressure heater), so that the water in the water inlet pipe 2-1 is fed to the high-pressure heater. This is not specifically described here and is within the scope of protection.

[0039] In some embodiments, the coal-fired unit further includes a hot air heater 6-1 having an air inlet pipe 5-1 and an air outlet pipe 5-2, the outlet end of which is connected to the coal boiler 6-2. The steam outlet of the biomass boiler 3-2 includes a steam main pipe 1-9 and a second steam pipe 1-10, with the first steam pipe 1-3 and the second steam pipe 1-10 connected to the outlet end of the steam main pipe 1-9. The steam inlet of the hot air heater 6-1 is connected to the second steam pipe 1-10 via the first steam inlet pipe 1-7, so that the steam entering the hot air heater 6-1 heats the air flow within the hot air heater 6-1, and the cooled steam is connected to the second steam inlet pipe 1-11 via the first steam outlet pipe 1-8. Through this arrangement, the superheated steam generated by the biomass boiler 3-2 burning biomass feedstock is used to heat the air flow (hot air) entering the coal boiler 6-2, eliminating the need for additional heating equipment. This simplifies the biomass coupled combustion system while avoiding the need for additional heat energy to heat the air flow (hot air), effectively saving energy.

[0040] To facilitate the distribution of superheated steam, in some embodiments, the outlet of the first steam outlet pipe 1-8 is connected to the second steam inlet pipe 1-11; the second steam pipeline 1-10 is connected to the second steam inlet pipe 1-11 through a first control pipeline; the first control pipeline has a first control valve 4-1, the first steam inlet pipe 1-7 has a second control valve 4-2, the first steam outlet pipe 1-8 has a third control valve 4-3, and the first steam pipeline 1-3 has a fourth control valve 3-3.

[0041] In addition, the cooled steam passes through the first steam outlet pipe 1-8 and the second steam inlet pipe 1-11 into the feed water heater 4-4 and is further cooled. It is then connected to the inlet of the first water supply pipe 1-2 through the second condensation outlet pipe 1-12 to realize the recycling of water energy, thereby further saving energy.

[0042] Of course, the cooled steam may also be allowed to directly enter the first water supply pipe 1 - 2 through the first steam outlet pipe 1 - 8 , which is not specifically limited here and is within the scope of protection.

[0043] In an embodiment in which all the superheated steam needs to be delivered to the biomass steam turbine 3-4, the fourth control valve 3-3 is opened, and the first control valve 4-1, the second control valve 4-2 and the third control valve 4-3 are all closed; in an embodiment in which a portion of the superheated steam needs to be delivered to the biomass steam turbine 3-4 and the other portion to the feed water heater 4-4, the fourth control valve 3-3 is opened, the first control valve 4-1 is opened, and the second control valve 4-2 and the third control valve 4-3 are closed; in an embodiment in which a portion of the superheated steam needs to be delivered to the biomass steam turbine 3-4 and the other portion to the feed water heater 4-4 and the hot air heater 6-1, the fourth control valve 3-3 is opened, the first control valve 4-1 is closed, and the second control valve 4-2 and the third control valve 4-3 are opened. In an embodiment where all the superheated steam needs to be transported to the feedwater heater 4-4, the fourth control valve 3-3, the second control valve 4-2 and the third control valve 4-3 are closed, and the first control valve 4-1 is opened; in an embodiment where all the superheated steam needs to be transported to the feedwater heater 4-4 and the hot air heater 6-1, the first control valve 4-1 and the fourth control valve 3-3 are closed, and the second control valve 4-2 and the third control valve 4-3 are opened.

[0044] Furthermore, high-temperature, high-pressure superheated steam flowing from the steam main pipe 1-9 of the biomass boiler 3-2 is controlled by the opening and closing of the fourth control valve 3-3 and the first control valve 4-1. This allows a portion of the superheated steam to be introduced into the feedwater heater 4-4 through the second steam inlet pipe 1-11 to heat the feedwater. This heats the feedwater entering the feedwater heater 4-4 through the feedwater inlet pipe 2-1 before flowing through the feedwater outlet pipe 2-2 into the economizer 6-3. The superheated steam introduced into the feedwater heater 4-4 by the second steam inlet pipe 1-11 is condensed into condensed water, which is pressurized by the second condensate outlet pipe 1-12 through the second feedwater pump 4-5 and mixed with the feedwater in the first feedwater pipe 1-2, completing the thermodynamic cycle. This heat exchange primarily utilizes the latent heat of the superheated steam transported by the second steam inlet pipe 1-11 condensing into the feedwater (condensed water) flowing into the second condensate outlet pipe 1-12, thereby improving the thermal efficiency of the original coal-fired unit (coal-fired unit) and reducing coal consumption.

[0045] Furthermore, by closing first control valve 4-1 and opening second control valve 4-2 and third control valve 4-3, superheated steam in second steam pipe 1-10 first passes through hot air heater 6-1 for heat exchange. The cooled superheated steam then passes through first steam outlet pipe 1-8 and enters feedwater heater 4-4 to heat the feedwater of the coal-fired unit (e.g., feedwater after high-pressure heater No. 1). This allows feedwater delivered by feedwater inlet pipe 2-1 to enter feedwater heater 4-4 for heating. Superheated steam from first steam outlet pipe 1-8 passes through second steam inlet pipe 1-11 and is introduced into feedwater heater 4-4, where it is condensed into condensate (feedwater). This condensate is then pressurized by second feedwater pump 4-5 on second condensate outlet pipe 1-12 and mixed with the feedwater in first feedwater pipe 1-2, completing the thermodynamic cycle. Feedwater delivered by feedwater inlet pipe 2-1 is heated by feedwater heater 4-4 to become high-temperature feedwater, which then flows through feedwater outlet pipe 2-2 into economizer 6-3. This part of the heat exchange mainly utilizes the sensible heat of the superheated steam in the second steam pipe 1-10 to heat the hot air of the coal boiler 6-2, and the latent heat of the superheated steam in the first steam outlet pipe 1-8 to condense into condensed water (feed water) in the second condensation outlet pipe 1-12, thereby achieving the effects of improving the thermal efficiency of the original coal-fired unit (coal-fired unit), reducing coal consumption and increasing drying output.

[0046] Furthermore, the boiler deaerator's feedwater outlet has a main water outlet pipe 1-1, which is equipped with a first feedwater pump 3-1. The inlet of the first feedwater pipe 1-2 is connected to the outlet of the main water outlet pipe 1-1. The second condensate outlet pipe 1-12 has a second feedwater pump 4-5, and the outlet of the second condensate outlet pipe 1-12 is connected to the main water outlet pipe 1-1. By providing different feedwater pumps, corresponding pressurization effects can be achieved.

[0047] In order to further improve the steam utilization rate, the coal-fired unit also includes a coal-fired unit high-pressure cylinder 6-5, and the coal-fired unit high-pressure cylinder 6-5 is connected to the reheat steam cold section pipe 1-5 of the low-temperature reheater 6-4; the outlet of the first exhaust steam pipe 1-4 is connected to the reheat steam cold section pipe 1-5, so that the steam flowing out of the outlet of the first exhaust steam pipe 1-4 and the steam discharged from the coal-fired unit high-pressure cylinder 6-5 are mixed in the reheat steam cold section pipe 1-5 and flow into the low-temperature reheater 6-4.

[0048] Specifically, in the biomass coupled combustion system provided by the present invention, feedwater is pressurized and accelerated by a first feedwater pump 3-1 (feedwater booster pump) through the outlet water main 1-1 of the coal-fired unit's boiler deaerator. The feedwater enters the biomass boiler 3-2 through the first feedwater pipe 1-2. The biomass boiler 3-2 burns the biomass feedstock and generates high-temperature, high-pressure superheated steam, which flows through the steam main 1-9 and enters, in whole or in part, the biomass steam turbine 3-4 (e.g., a back-pressure turbine), enabling the biomass power generation equipment to generate electricity. The steam then flows through the first exhaust steam pipe 1-4 into the coal-fired unit's reheat steam cold-section pipe 1-5. The steam then mixes with the steam in the reheat steam cold-section pipe 1-5 and enters the coal-fired unit's low-temperature reheater 6-4 for heating. This arrangement completes the power generation process of the biomass parallel combustion system.

[0049] In some embodiments, the first and second feeding structures are relatively independent. That is, different feeding structures are used to feed the coal boiler 6-2 and the biomass boiler 3-2, respectively. Coal feed enters the coal boiler 6-2 through the first feeding structure, and biomass feed enters the biomass boiler 3-2 through the second feeding structure, thereby preventing the different feeds from mixing and affecting the combustion effect.

[0050] The second feeding structure includes a biomass feeder 7-1 and a biomass conveyor 7-2; the biomass conveyor 7-2 connects the outlet of the biomass feeder 7-1 with the inlet of the biomass boiler 3-2.

[0051] In order to realize the recovery of flue gas, the second flue gas outlet is connected to the absorption tower 6-7 through the second flue gas duct 7-3. That is, the absorption tower 6-7 can be used to absorb the flue gas of the coal boiler 6-2 and the biomass boiler 3-2.

[0052] In some embodiments, the outlet of the second flue gas duct 7-3 is connected to the first flue gas duct 6-6. That is, the structure of the absorption tower 6-7 can be left unchanged, allowing the flue gases from the coal boiler 6-2 and the biomass boiler 3-2 to flow into the absorption tower 6-7. Alternatively, an additional flue gas inlet can be provided within the absorption tower 6-7.

[0053] Specifically, the biomass coupled combustion system provided in the embodiment of the present invention transports the biomass raw materials to the biomass boiler 3-2, and after being fully burned and subjected to denitrification and dust removal treatment, it is absorbed through the second flue gas duct 7-3 and the absorption tower 6-7 of the coal-fired unit.

[0054] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0055] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A biomass coupled combustion system, characterized in that: include: A coal-fired unit, comprising a coal boiler (6-2), an economizer (6-3), a low-temperature reheater (6-4), an absorption tower (6-7) and a boiler deaerator, wherein the coal boiler (6-2) has a first feed structure, a first ash outlet and a first flue gas outlet, the economizer (6-3) and the low-temperature reheater (6-4) are arranged in the coal boiler (6-2), and the absorption tower (6-7) is connected to the first flue gas outlet via a first flue gas duct (6-6); A biomass boiler (3-2), the biomass boiler (3-2) having a second feed structure, a second ash outlet and a second flue gas outlet, the first ash outlet and the second ash outlet being relatively independent, the water feed outlet of the boiler deaerator being in communication with the water inlet of the biomass boiler (3-2) via a first water feed pipe (1-2); A biomass power generation device, comprising a biomass steam turbine (3-4), wherein the biomass steam turbine (3-4) is connected to the steam outlet of the biomass boiler (3-2) via a first steam pipe (1-3), so that the biomass steam turbine (3-4) generates electricity using steam provided by the first steam pipe (1-3), and the exhaust steam outlet of the biomass steam turbine (3-4) is connected to the low-temperature reheater (6-4) via the first exhaust steam pipe (1-4).

2. The biomass coupled combustion system according to claim 1, characterized in that: The coal-fired unit further comprises a feedwater heater (4-4), the feedwater heater (4-4) having a feedwater inlet pipe (2-1) and a feedwater outlet pipe (2-2), the outlet end of the feedwater outlet pipe (2-2) being in communication with the economizer (6-3); The steam outlet of the biomass boiler (3-2) comprises a steam main pipe (1-9) and a second steam pipe (1-10), and the first steam pipe (1-3) and the second steam pipe (1-10) are in communication with the outlet end of the steam main pipe (1-9); The steam inlet of the feedwater heater (4-4) is connected to the second steam pipe (1-10) through the second steam inlet pipe (1-11), so that the steam entering the feedwater heater (4-4) heats the feedwater in the feedwater heater (4-4), and the cooled steam is connected to the inlet of the first feedwater pipe (1-2) through the second condensation outlet pipe (1-12).

3. The biomass coupled combustion system according to claim 2, characterized in that: The coal-fired unit further comprises a hot air heater (6-1), the hot air heater (6-1) having an air flow inlet pipe (5-1) and an air flow outlet pipe (5-2), the outlet end of the air flow outlet pipe (5-2) being in communication with the coal boiler (6-2); The steam inlet of the hot air heater (6-1) is connected to the second steam pipe (1-10) through the first steam inlet pipe (1-7), so that the steam entering the hot air heater (6-1) heats the air flow in the hot air heater (6-1), and the cooled steam is connected to the second steam inlet pipe (1-11) through the first steam outlet pipe (1-8).

4. The biomass coupled combustion system according to claim 3, characterized in that: The outlet of the first steam outlet pipe (1-8) is in communication with the second steam inlet pipe (1-11); The second steam pipeline (1-10) is connected to the second steam inlet pipe (1-11) via a first control pipeline; The first control pipeline has a first control valve (4-1), the first steam inlet pipe (1-7) has a second control valve (4-2), the first steam outlet pipe (1-8) has a third control valve (4-3), and the first steam pipeline (1-3) has a fourth control valve (3-3).

5. The biomass coupled combustion system according to claim 3, characterized in that: The water supply outlet of the boiler deaerator is provided with a water supply main pipe (1-1), the water supply main pipe (1-1) is provided with a first water supply pump (3-1), and the inlet of the first water supply pipe (1-2) is connected to the outlet of the water supply main pipe (1-1); The second condensate outlet pipe (1-12) is provided with a second water supply pump (4-5), and the outlet of the second condensate outlet pipe (1-12) is connected to the water outlet main pipe (1-1).

6. The biomass coupled combustion system according to claim 1, characterized in that: The coal-fired unit further comprises a coal-fired unit high-pressure cylinder (6-5), and a reheat steam cold section pipeline (1-5) between the coal-fired unit high-pressure cylinder (6-5) and the low-temperature reheater (6-4); The outlet of the first exhaust steam pipe (1-4) is connected to the reheat steam cold section pipe (1-5), so that the steam flowing out of the outlet of the first exhaust steam pipe (1-4) and the steam discharged from the high-pressure cylinder (6-5) of the coal-fired unit are mixed in the reheat steam cold section pipe (1-5) and flow into the low-temperature reheater (6-4).

7. The biomass coupled combustion system according to claim 1, characterized in that: The first feeding structure and the second feeding structure are relatively independent.

8. The biomass coupled combustion system according to claim 7, characterized in that: The second feeding structure includes a biomass feeder (7-1) and a biomass conveyor (7-2); The biomass conveyor (7-2) connects the outlet of the biomass feeder (7-1) and the inlet of the biomass boiler (3-2).

9. The biomass coupled combustion system according to claim 1, characterized in that: The second flue gas outlet is connected to the absorption tower (6-7) through a second flue gas duct (7-3).

10. The biomass coupled combustion system according to claim 9, characterized in that: The outlet of the second flue gas duct (7-3) is in communication with the first flue gas duct (6-6).

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