Flue gas utilization system and method for pure oxygen combustion biomass boiler

Abstract

The invention relates to the technical field of boiler combustion flue gas and air systems, in particular to a pure oxygen combustion biomass boiler flue gas utilization system and method. The pure oxygen combustion boiler flue gas utilization system comprises a boiler, a dust remover, a carbon dioxide recovery assembly and a gas uniformizing box, the flue gas output end of the boiler is communicated with the dust remover, one part of the output end of the dust remover is communicated with the carbon dioxide recovery assembly, and the other part of the output end of the dust remover is communicated with the gas uniformizing box through a flue gas channel. The gas equalizing box is externally connected with a pure oxygen input channel, the pure oxygen and the flue gas are mixed into mixed flue gas in the gas equalizing box, and the output end of the gas equalizing box is communicated with the boiler. According to the flue gas utilization system for the pure oxygen combustion biomass boiler, flue gas and pure oxygen are mixed through the gas homogenizing box, preparation of mixed flue gas is completed in front of the boiler, oxygen and heat in the flue gas are fully utilized, meanwhile, the oxygen content in the mixed flue gas is conveniently controlled, adjustment can be conducted according to the temperature of the boiler, and pipe explosion accidents of the boiler are reduced.

Description

Technical Field

[0001] The invention relates to the technical field of boiler combustion smoke and air systems, and in particular to a system and method for utilizing smoke from a pure oxygen combustion biomass boiler. Background Art

[0002] Since the last century, the capture and application technology of carbon dioxide has been studied, but due to the high cost of capture, this technology has been in the research and experimental stage. The cost of carbon dioxide capture is closely related to the concentration of carbon dioxide, and a high concentration of carbon dioxide is conducive to reducing the capture cost of carbon dioxide. In order to increase the concentration of carbon dioxide, a technical route using pure oxygen combustion is proposed. Pure oxygen combustion has the characteristics of high combustion efficiency, low flue gas volume, and high boiler efficiency. After continuous exploration, green hydrogen projects have been emerging, and a large amount of oxygen is produced as a by-product. In the case of industrial chain coupling, pure oxygen can be used as a combustion aid to participate in combustion, and pure oxygen participating in boiler combustion can easily cause the furnace temperature of the boiler to be too high, resulting in the explosion of boiler pipes.

[0003] The Chinese invention patent with publication number CN117053218A discloses a system and method for utilizing flue gas and carbon resources of a pure oxygen combustion biomass boiler. The system includes a water electrolysis mechanism, a boiler, an air supply mechanism and a carbon utilization mechanism. The water electrolysis mechanism prepares hydrogen and oxygen. The first three-way valve divides the flue gas at the flue gas outlet of the boiler into two parts. The first part of the flue gas enters the dust collector. The dust collector, the cooler, the compression device and the cooler are connected in sequence. The cooler is connected to a liquid carbon dioxide storage tank. The second part of the flue gas returns to the boiler furnace. The primary air mechanism and the secondary air mechanism receive oxygen from the water electrolysis mechanism. The carbon utilization mechanism pressurizes the hydrogen from the water electrolysis mechanism and the carbon dioxide from the liquid carbon dioxide storage tank and sends them to a methanol synthesis device to generate methanol.

[0004] The above-mentioned pure oxygen combustion biomass boiler flue gas and carbon resource utilization system prepares hydrogen and oxygen through a water electrolysis mechanism. The pure oxygen combustion biomass boiler flue gas and carbon resource utilization system has the advantages of efficient utilization of electrolysis products, low carbon capture cost, and improved resource utilization. However, the pure oxygen combustion boiler is prone to cause the boiler furnace temperature to be too high, resulting in the boiler's explosive pipes, and lacks the ability to adjust the amount of pure oxygen input into the boiler. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a pure oxygen combustion biomass boiler flue gas utilization system and method. The pure oxygen combustion biomass boiler flue gas utilization system mixes flue gas and pure oxygen through an air homogenization box, completes the preparation of the mixed flue gas in front of the boiler, and makes full use of the oxygen and heat in the flue gas. At the same time, it is easy to control the oxygen content in the mixed flue gas, which can be adjusted according to the boiler temperature to reduce boiler pipe burst accidents.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0007] A pure oxygen combustion biomass boiler flue gas utilization system, which includes a boiler, a dust collector, a carbon dioxide recovery component and an air equalization box, the flue gas output end of the boiler is connected to the dust collector, a part of the output end of the dust collector is connected to the carbon dioxide recovery component, and the other part is connected to the air equalization box through a flue gas channel, the flue gas channel is provided with a flue gas flow control device, the air equalization box is externally connected to a pure oxygen input channel, the pure oxygen input channel is provided with a pure oxygen flow control device, the pure oxygen and flue gas are mixed into mixed flue gas in the air equalization box, the output end of the air equalization box is connected to the boiler, and a mixed flue gas oxygen content monitoring device is provided between the air equalization box and the boiler.

[0008] Furthermore, the boiler is a positive pressure boiler.

[0009] Furthermore, the boiler is a biomass boiler.

[0010] Furthermore, the boiler includes a steam generator, a furnace, a burner and a tail flue, the burner burns in the furnace to heat the steam generator, and the flue gas generated by the combustion of the burner is discharged through the tail flue.

[0011] Furthermore, the furnace is provided with a metal tube wall.

[0012] Furthermore, the furnace is also provided with a temperature sensor, and the temperature sensor is used to monitor the temperature of the metal pipe wall.

[0013] Furthermore, the carbon dioxide recovery component comprises a carbon dioxide desulfurization device, a carbon dioxide drying device and a carbon dioxide compression device which are connected in sequence.

[0014] Furthermore, it includes a booster fan, which is arranged in the flue gas channel and located between the flue gas flow control device and the dust collector.

[0015] Furthermore, it also includes a controller, and the flue gas flow control device, the pure oxygen flow control device, the mixed flue gas oxygen content monitoring device and the temperature sensor are all electrically connected to the controller.

[0016] In a second aspect, the present invention further provides a method for utilizing flue gas from a pure oxygen combustion biomass boiler, which comprises the following steps:

[0017] S1: After the boiler is burned, it emits flue gas with high carbon dioxide concentration. The flue gas is dedusted by the dust collector. Part of the flue gas after dedusting enters the carbon dioxide recovery component for recycling and treatment, and the other part of the flue gas enters the gas equalization box in a recirculated manner through the flue gas channel;

[0018] S2: a smoke flow control device is arranged on the smoke channel, and the smoke flow control device is used to control the smoke flow entering the gas equalizing box;

[0019] S3: The input end of the gas equalizing box is externally connected to a pure oxygen input channel, and a pure oxygen flow control device is provided on the pure oxygen input channel. Pure oxygen enters the gas equalizing box through the pure oxygen input channel, and the pure oxygen flow control device controls the pure oxygen flow entering the gas equalizing box;

[0020] S4: Pure oxygen and flue gas are mixed into mixed flue gas in a gas-equalizing box. A mixed flue gas oxygen content monitoring device is arranged at the outlet of the gas-equalizing box. The mixed flue gas oxygen content monitoring device is used to monitor the oxygen content in the mixed flue gas. By controlling the flue gas flow rate and the pure oxygen flow rate, the oxygen content of the mixed flue gas is kept at 21% under normal conditions. Then the mixed flue gas enters the boiler again, mixes with the fuel, participates in combustion, and the flue gas generated by the combustion is recovered and circulated;

[0021] S5: Monitor the temperature of the metal tube wall in the boiler furnace, and adjust the oxygen content of the mixed flue gas according to the temperature of the metal tube wall. When the temperature of the metal tube wall is higher than the set threshold, reduce the oxygen content in the mixed flue gas, reduce the temperature of the furnace flame, and reduce the temperature of the metal tube wall. Similarly, when the temperature of the metal tube wall is lower than the set threshold, increase the oxygen content in the mixed flue gas, where the threshold value of the oxygen content in the mixed flue gas is 21%.

[0022] Beneficial effects of the invention: The invention discloses a pure oxygen combustion biomass boiler flue gas utilization system, comprising a boiler, a dust collector, a carbon dioxide recovery component and an air equalization box, the flue gas output end of the boiler is connected to the dust collector, a part of the output end of the dust collector is connected to the carbon dioxide recovery component, and the other part is connected to the air equalization box through a flue gas channel, the flue gas channel is provided with a flue gas flow control device, the air equalization box is externally connected to a pure oxygen input channel, the pure oxygen input channel is provided with a pure oxygen flow control device, the pure oxygen and flue gas are mixed into mixed flue gas in the air equalization box, the output end of the air equalization box is connected to the boiler, and a mixed flue gas oxygen content monitoring device is provided between the air equalization box and the boiler. The boiler is used for combustion to produce flue gas with high carbon dioxide concentration. The flue gas is dedusted by a dust collector. A part of the flue gas after dedusting is recovered by a carbon dioxide recovery component. The other part of the flue gas after dedusting enters the gas equalization box through the flue gas channel. The flue gas channel is used for flue gas transmission. The gas equalization box is used to mix the flue gas and pure oxygen into mixed flue gas. The gas equalization box obtains a pure oxygen source through a pure oxygen input channel. The flue gas flow control device is used to control the flue gas flow entering the gas equalization box. The pure oxygen flow control device is used to control the pure oxygen entering the gas equalization box. The mixed flue gas oxygen content monitoring device is used to monitor the mixed gas output from the gas equalization box. The oxygen content of the flue gas is monitored, and the pure oxygen flow rate and the flue gas flow rate are adjusted by setting the oxygen content threshold of the mixed flue gas under normal conditions; the present invention also provides a method for utilizing the flue gas of a pure oxygen combustion biomass boiler, wherein the mixed flue gas enters the boiler to participate in the boiler combustion, wherein the pure oxygen participates in the boiler combustion, which can increase the carbon dioxide concentration in the flue gas, improve the combustion efficiency, and reduce the waste of working fluids. At the same time, by reducing the flow rate of pure oxygen, when the boiler temperature is too high, the boiler flame temperature can be reduced, and the stability of the boiler operation can be improved. In the repeated circulation process of the flue gas, the oxygen content in the flue gas can be further utilized to recover the heat in the flue gas. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a structural schematic diagram of a flue gas utilization system of a pure oxygen combustion biomass boiler of the present invention;

[0024] Figure 2 The present invention is a schematic structural diagram of a carbon dioxide recovery component of a pure oxygen combustion biomass boiler flue gas utilization system.

[0025] Explanation of the accompanying drawings: 1-dust collector, 2-air equalization box, 3-flue gas channel, 4-flue gas flow control device, 5-pure oxygen input channel, 6-pure oxygen flow control device, 7-mixed flue gas oxygen content monitoring device, 8-steam generator, 9-furnace, 10-burner, 11-tail flue, 12-carbon dioxide desulfurization device, 13-carbon dioxide drying device, 14-carbon dioxide compression device, 15-boosting fan. DETAILED DESCRIPTION

[0026] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0027] It should be understood that the terms used herein are only for the purpose of describing specific example embodiments and are not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms "one", "an" and "said" as used herein may also be meant to include plural forms. The terms "include", "comprise", "contain", and "have" are inclusive and therefore specify the existence of stated features, steps, operations, elements and / or parts, but do not exclude the existence or addition of one or more other features, steps, operations, elements, parts and / or combinations thereof. The method steps, processes, and operations described herein are not interpreted as necessarily requiring them to be performed in the specific order described or illustrated, unless the execution order is clearly indicated. It should also be understood that additional or alternative steps may be used.

[0028] Although the terms first, second, third, etc. can be used in the text to describe multiple elements, components, regions, layers and / or sections, these elements, components, regions, layers and / or sections should not be limited by these terms. These terms can only be used to distinguish an element, component, region, layer or section from another region, layer or section. Unless the context clearly indicates, terms such as "first", "second" and other numerical terms do not imply order or sequence when used in the text. Therefore, the first element, component, region, layer or section discussed below can be referred to as the second element, component, region, layer or section without departing from the teaching of the example embodiments.

[0029] For ease of description, spatial relative terms may be used in the text to describe the relationship of one element or feature relative to another element or feature as shown in the figure, such as "inside", "outside", "inner side", "outer side", "below", "below", "above", "above", etc. Such spatial relative terms include different orientations of the device in use or operation in addition to the orientation depicted in the figure. For example, if the device in the figure is turned over, the element described as "below other elements or features" or "below other elements or features" will then be oriented as "above other elements or features" or "above other elements or features". Therefore, the example term "below..." can include both upper and lower orientations. The device can be oriented otherwise (rotated 90 degrees or in other directions) and the spatial relative descriptors used in the text are interpreted accordingly.

[0030] Embodiment 1:

[0031] like Figure 1 and Figure 2As shown, the present embodiment provides a pure oxygen combustion biomass boiler flue gas utilization system, which includes a boiler, a dust collector 1, a carbon dioxide recovery component and an air equalization box 2, the flue gas output end of the boiler is connected to the dust collector 1, a part of the output end of the dust collector 1 is connected to the carbon dioxide recovery component, and the other part is connected to the air equalization box 2 through a flue gas channel 3, the flue gas channel 3 is provided with a flue gas flow control device 4, the air equalization box 2 is externally connected to a pure oxygen input channel 5, the pure oxygen input channel 5 is provided with a pure oxygen flow control device 6, the pure oxygen and flue gas are mixed into mixed flue gas in the air equalization box 2, the output end of the air equalization box 2 is connected to the boiler, and a mixed flue gas oxygen content monitoring device 7 is provided between the air equalization box 2 and the boiler. In actual use, the boiler is used for combustion to generate flue gas with high carbon dioxide concentration, the flue gas is dedusted by the dust collector 1, a part of the flue gas after dedusting is recovered by the carbon dioxide recovery component, and the other part of the flue gas after dedusting enters the gas equalization box 2 through the flue gas channel 3, the flue gas channel 3 is used for flue gas transmission, the gas equalization box 2 is used to mix the flue gas and pure oxygen into mixed flue gas, the gas equalization box 2 obtains the pure oxygen source through the pure oxygen input channel 5, the flue gas flow control device 4 is used to control the flue gas flow entering the gas equalization box 2, the pure oxygen flow control device 6 is used to control the pure oxygen entering the gas equalization box 2, and the mixed The flue gas oxygen content monitoring device 7 is used to monitor the oxygen content of the mixed flue gas output by the gas equalizing box 2. By setting the oxygen content threshold of the mixed flue gas under normal conditions, the pure oxygen flow rate and the flue gas flow rate can be adjusted. The mixed flue gas enters the boiler to participate in the boiler combustion. The pure oxygen participates in the boiler combustion, which can increase the carbon dioxide concentration in the flue gas, improve the combustion efficiency, and reduce the waste of working fluids. At the same time, by reducing the flow rate of pure oxygen, when the boiler temperature is too high, the boiler flame temperature can be reduced, and the stability of the boiler operation can be improved. In the repeated circulation process of the flue gas, the oxygen content in the flue gas can be further utilized to recover the heat in the flue gas.

[0032] In this embodiment, the boiler is a positive pressure boiler. In actual use, the boiler is a positive pressure boiler, which can prevent air from leaking into the boiler, thereby reducing the concentration of carbon dioxide.

[0033] In this embodiment, the boiler is a biomass boiler. In actual use, the biomass boiler uses biomass fuel as the combustion material, and biomass combustion is a combustible clean fuel, which is energy-saving and environmentally friendly.

[0034] In this embodiment, the boiler includes a steam generator 8, a furnace 9, a burner 10 and a tail flue 11. The burner 10 burns in the furnace 9 to heat the steam generator 8, and the flue gas generated by the combustion of the burner 10 is discharged through the tail flue 11. In actual use, the burner 10 generates flue gas with a high carbon dioxide concentration through combustion, and the flue gas is discharged through the tail flue 11. At the same time, the burner 10 heats the steam generator 8 by burning the matching furnace 9, providing heat source support for the steam generator 8.

[0035] In this embodiment, the furnace 9 is provided with a metal tube wall. In actual use, in order to improve the sealing performance of the furnace 9 and the heat transfer performance of the furnace 9, the metal tube wall is used to facilitate efficient heat transfer and safe operation of the furnace 9.

[0036] In this embodiment, the furnace 9 is also provided with a temperature sensor, which is used to monitor the temperature of the metal tube wall. In actual use, the temperature sensor is used to monitor the temperature of the metal tube wall. When the temperature of the metal tube wall exceeds the set threshold, timely feedback is made for adjustment to prevent the metal tube wall from overheating for a long time, resulting in boiler tube burst.

[0037] In this embodiment, the carbon dioxide recovery component includes a carbon dioxide desulfurization device 12, a carbon dioxide drying device 13 and a carbon dioxide compression device 14 connected in sequence. In actual use, the boiler combustion produces flue gas with a high carbon dioxide concentration, and a part of the flue gas enters the gas equalization box 2 for circulation. After the circulating flue gas volume and the pure oxygen volume reach a dynamic balance, the excess flue gas passes through the carbon dioxide desulfurization device 12 and the carbon dioxide drying device 13 to extract high-purity carbon dioxide. The high-purity carbon dioxide is compressed by the carbon dioxide compression device 14 and sent to the chemical device as a chemical raw material to prepare chemical products, such as methanol, soda ash, etc.

[0038] In this embodiment, a booster fan 15 is included, and the booster fan 15 is arranged in the smoke channel 3, and the booster fan 15 is located between the smoke flow control device 4 and the dust collector 1. In actual use, the smoke enters the gas equalizing box 2 through the smoke channel 3. By arranging the booster fan 15 in the smoke channel 3, the speed of the smoke passing through the smoke channel 3 is increased, the smoke is pressurized, and it is ensured that the smoke passes through the smoke channel 3 smoothly and enters the gas equalizing box 2.

[0039] In this embodiment, a controller is also included, and the flue gas flow control device 4, the pure oxygen flow control device 6, the mixed flue gas oxygen content monitoring device 7 and the temperature sensor are all electrically connected to the controller. In actual use, the connected devices are controlled by the controller, and the monitoring data of the flue gas oxygen content monitoring device 7 is transmitted to the controller for analysis and processing, and then the flue gas flow control device 4 and the pure oxygen flow control device 6 are controlled to adjust the input amount of pure oxygen and flue gas, and the oxygen content of the mixed flue gas is kept at 21% under normal conditions. Similarly, the monitoring data of the temperature sensor is transmitted to the controller for analysis and processing. When the temperature of the metal pipe wall is higher than the set threshold, the controller controls the pure oxygen flow control device 6 to reduce the input of pure oxygen, thereby reducing the oxygen content in the mixed flue gas, reducing the temperature of the furnace 9 flame, reducing the temperature of the metal pipe wall, ensuring the normal operation of the furnace 9, and preventing the furnace 9 from bursting due to excessive temperature.

[0040] Embodiment 2:

[0041] like Figure 1 and Figure 2 As shown, based on the first embodiment, the present invention also provides a method for utilizing flue gas from a pure oxygen combustion biomass boiler, comprising the following steps:

[0042] S1: After the boiler is burned, flue gas with high carbon dioxide concentration is discharged. The flue gas is dedusted by the dust collector 1. A part of the flue gas after dedusting enters the carbon dioxide recovery component for recycling and treatment, and the other part of the flue gas enters the gas equalization box 2 in a recirculating manner through the flue gas channel 3;

[0043] S2: a smoke flow control device 4 is provided on the smoke channel 3, and the smoke flow control device 4 is used to control the smoke flow entering the gas equalizing box 2;

[0044] S3: The input end of the gas equalizing box 2 is externally connected to a pure oxygen input channel 5, and a pure oxygen flow control device 6 is provided on the pure oxygen input channel 5. Pure oxygen enters the gas equalizing box 2 through the pure oxygen input channel 5, and the pure oxygen flow control device 6 controls the pure oxygen flow entering the gas equalizing box 2;

[0045] S4: Pure oxygen and flue gas are mixed into mixed flue gas in the gas equalization box 2. A mixed flue gas oxygen content monitoring device 7 is provided at the outlet of the gas equalization box 2. The mixed flue gas oxygen content monitoring device 7 is used to monitor the oxygen content in the mixed flue gas. By controlling the flue gas flow rate and the pure oxygen flow rate, the oxygen content of the mixed flue gas is kept at 21% under normal conditions. Then the mixed flue gas enters the boiler again, mixes with the fuel, participates in combustion, and the flue gas generated by the combustion is recovered and circulated;

[0046] S5: Monitor the temperature of the metal tube wall of the boiler furnace 9, and adjust the oxygen content of the mixed flue gas according to the temperature of the metal tube wall. When the temperature of the metal tube wall is higher than the set threshold, reduce the oxygen content in the mixed flue gas, reduce the temperature of the furnace 9 flame, and reduce the temperature of the metal tube wall. Similarly, when the temperature of the metal tube wall is lower than the set threshold, increase the oxygen content in the mixed flue gas, wherein the threshold value of the oxygen content in the mixed flue gas is 21%.

[0047] After combustion, the boiler emits flue gas with a high carbon dioxide concentration. The flue gas is dedusted by a dust collector 1. A part of the flue gas after dedusting is recovered by a carbon dioxide recovery component, and the other part of the flue gas after dedusting enters the gas equalizing box 2 through the flue gas channel 3. The gas equalizing box 2 obtains a pure oxygen source through a pure oxygen input channel 5. The pure oxygen flow rate and the flue gas flow rate are adjusted by setting a threshold value of the oxygen content of the mixed flue gas under normal conditions. The mixed flue gas enters the boiler to participate in boiler combustion, thereby improving combustion efficiency and reducing waste of working fluids. By monitoring the temperature of the metal pipe wall of the boiler furnace 9, the oxygen content of the mixed flue gas can be adjusted according to the temperature of the metal pipe wall. When the boiler temperature is too high, the boiler flame temperature can be reduced to improve the stability of boiler operation.

[0048] All technical features in this embodiment can be freely combined according to actual needs. The above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention is described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution of the present invention, which should be covered by the scope of the claims of the present invention. The technology, shape, and structural parts not described in detail in the present invention are all well-known technologies.

[0049] The above embodiments are preferred implementation schemes of the present invention. In addition, other implementation schemes are also included. Any obvious replacement without departing from the concept of the present technical scheme is within the protection scope of the present invention.

Claims

1. A pure oxygen combustion biomass boiler flue gas utilization system, characterized by: The invention comprises a boiler, a dust collector (1), a carbon dioxide recovery component and an air equalization box (2), wherein the flue gas output end of the boiler is connected to the dust collector (1), a part of the output end of the dust collector (1) is connected to the carbon dioxide recovery component, and the other part is connected to the air equalization box (2) through a flue gas channel (3), the flue gas channel (3) is provided with a flue gas flow control device (4), the air equalization box (2) is externally connected to a pure oxygen input channel (5), the pure oxygen input channel (5) is provided with a pure oxygen flow control device (6), the pure oxygen and flue gas are mixed into mixed flue gas in the air equalization box (2), the output end of the air equalization box (2) is connected to the boiler, and a mixed flue gas oxygen content monitoring device (7) is provided between the air equalization box (2) and the boiler.

2. The pure oxygen combustion biomass boiler flue gas utilization system according to claim 1, characterized in that: The boiler is a positive pressure boiler.

3. The pure oxygen combustion biomass boiler flue gas utilization system according to claim 1, characterized in that: The boiler is a biomass boiler.

4. The pure oxygen combustion biomass boiler flue gas utilization system according to claim 1, characterized in that: The boiler comprises a steam generator (8), a furnace (9), a burner (10) and a tail flue (11); the burner (10) burns in the furnace (9) to heat the steam generator (8); and the flue gas generated by the combustion of the burner (10) is discharged through the tail flue (11).

5. A pure oxygen combustion biomass boiler flue gas utilization system according to claim 4, characterized in that: The furnace (9) is provided with a metal tube wall.

6. A pure oxygen combustion biomass boiler flue gas utilization system according to claim 5, characterized in that: The furnace (9) is also provided with a temperature sensor, which is used to monitor the temperature of the metal pipe wall.

7. The pure oxygen combustion biomass boiler flue gas utilization system according to claim 1, characterized in that: The carbon dioxide recovery component comprises a carbon dioxide desulfurization device (12), a carbon dioxide drying device (13) and a carbon dioxide compression device (14) which are connected in sequence.

8. The pure oxygen combustion biomass boiler flue gas utilization system according to claim 1, characterized in that: It comprises a booster fan (15), wherein the booster fan (15) is arranged in the smoke passage (3), and the booster fan (15) is located between the smoke flow control device (4) and the dust collector (1).

9. The pure oxygen combustion biomass boiler flue gas utilization system according to claim 6, characterized in that: It also comprises a controller, and the flue gas flow control device (4), the pure oxygen flow control device (6), the mixed flue gas oxygen content monitoring device (7) and the temperature sensor are all electrically connected to the controller.

10. A method for utilizing flue gas from a pure oxygen combustion biomass boiler, characterized in that: The pure oxygen combustion biomass boiler flue gas utilization system according to claim 1 comprises the following steps: S1: After the boiler is burned, it emits flue gas with high carbon dioxide concentration. The flue gas is dedusted by the dust collector. Part of the flue gas after dedusting enters the carbon dioxide recovery component for recycling and treatment, and the other part of the flue gas enters the gas equalization box in a recirculated manner through the flue gas channel; S2: a smoke flow control device is arranged on the smoke channel, and the smoke flow control device is used to control the smoke flow entering the gas equalizing box; S3: The input end of the gas equalizing box is externally connected to a pure oxygen input channel, and a pure oxygen flow control device is provided on the pure oxygen input channel. Pure oxygen enters the gas equalizing box through the pure oxygen input channel, and the pure oxygen flow control device controls the pure oxygen flow entering the gas equalizing box; S4: Pure oxygen and flue gas are mixed into mixed flue gas in a gas-equalizing box. A mixed flue gas oxygen content monitoring device is arranged at the outlet of the gas-equalizing box. The mixed flue gas oxygen content monitoring device is used to monitor the oxygen content in the mixed flue gas. By controlling the flue gas flow rate and the pure oxygen flow rate, the oxygen content of the mixed flue gas is kept at 21% under normal conditions. Then the mixed flue gas enters the boiler again, mixes with the fuel, participates in combustion, and the flue gas generated by the combustion is recovered and circulated; S5: Monitor the temperature of the metal tube wall in the boiler furnace, and adjust the oxygen content of the mixed flue gas according to the temperature of the metal tube wall. When the temperature of the metal tube wall is higher than the set threshold, reduce the oxygen content in the mixed flue gas, reduce the temperature of the furnace flame, and reduce the temperature of the metal tube wall. Similarly, when the temperature of the metal tube wall is lower than the set threshold, increase the oxygen content in the mixed flue gas, where the threshold value of the oxygen content in the mixed flue gas is 21%.

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