Device and method for flue gas treatment and waste heat utilization of industrial furnace

Abstract

The invention belongs to the field of petrochemical engineering and bioengineering, and relates to a device and method for industrial furnace flue gas treatment and waste heat utilization. Comprising an industrial furnace system, a carbon dioxide trapping system and a biological treatment system, the industrial furnace system comprises an industrial furnace, an air blower and a preheater. The carbon dioxide trapping system comprises an induced draft fan, a reboiler, a desorption tower, an absorption tower and a heat exchanger; the biological treatment system comprises a buffer tank, a photobioreactor and a centrifugal dryer; the NOx-containing flue gas discharge pipeline is connected with the photobioreactor, the CO2 discharge pipeline is sequentially connected with the buffer tank and the photobioreactor, the photobioreactor is provided with an algae liquid discharge pipeline, the algae liquid discharge pipeline is connected with the centrifugal dryer, the algae liquid dry air feed pipeline is sequentially connected with the heat exchanger and the centrifugal dryer, and the centrifugal dryer is provided with a dry algae powder discharge port. According to the invention, carbon dioxide and nitrogen oxide in the flue gas of the industrial furnace are treated, carbon dioxide and nitrogen oxide are removed, and the algae powder product with profit is produced.

Description

Technical Field

[0001] The present invention belongs to the fields of petrochemical industry and bioengineering. Specifically, it relates to a device and method for industrial furnace flue gas treatment and waste heat utilization. Background Art

[0002] In industrial production, tubular heating furnaces are widely used in the oil refining and chemical industries. The heating furnace can provide a large amount of heat for the products in the production process to ensure that the raw materials undergo corresponding physical and chemical reactions at the specified temperature. During the operation of the heating furnace, fuel combustion is required, and a large amount of combustion-supporting air is needed for fuel combustion, generating a large amount of flue gas. The main components of the flue gas are carbon dioxide, nitrogen oxides, nitrogen, and oxygen.

[0003] With the development of energy conservation and emission reduction technologies, low-nitrogen oxide burners are generally used in heating furnaces. This type of burner can significantly reduce the nitrogen oxide content in the flue gas. However, it is difficult to further achieve the elimination of carbon dioxide in the flue gas only through the development of burner technology. Currently, the removal of carbon dioxide in the flue gas can mainly be solved from the fuel end and the emission end. Among them, the method at the fuel end is generally to use low-carbon fuels, such as hydrogen fuel. Due to its high price, hydrogen fuel is currently not suitable for long-term use in heating furnaces. Solving from the emission end generally uses carbon dioxide capture technology, such as chemical absorption method. The basic principle of the chemical absorption method is to capture and absorb carbon dioxide in the flue gas through a chemical absorbent, and then heat and decompose the absorbent to decompose high-concentration carbon dioxide gas, thereby achieving carbon dioxide capture.

[0004] As a plant with high photosynthetic efficiency, microalgae consume carbon dioxide during photosynthesis, producing oxygen and sugar substances. In addition, since plant growth requires nitrogen-based fertilizers, nitrogen oxides in the flue gas can become nitrogen-based fertilizers for microalgae after dissolving in water. Currently, the main factor limiting the cost of microalgae powder is the drying cost, which is generally 5000 yuan / ton, and more than 90% of the cost is the heating cost of drying air.

[0005] Therefore, if the carbon dioxide capture process, microalgae cultivation process, and heating furnace process can be integrated and innovated, not only can the carbon dioxide and nitrogen oxides in the flue gas be treated, but also the costs of the capture process and microalgae cultivation process can be further reduced by using the waste heat of the heating furnace flue gas, ultimately achieving the treatment and waste heat utilization of the flue gas. Summary of the Invention

[0006] The purpose of the present invention is to provide a device and method for industrial furnace flue gas treatment and waste heat utilization, which can greenly treat carbon dioxide and nitrogen oxides in industrial furnace flue gas, and at the same time use the waste heat in the heating furnace flue gas to provide heat for the carbon dioxide capture process and microalgae drying, further reducing the operating cost and providing the possibility for industrial application.

[0007] To achieve the above object, a first aspect of the present invention provides a device for industrial furnace flue gas treatment and waste heat utilization, comprising: an industrial furnace system, a carbon dioxide capture system, and a biological treatment system;

[0008] The industrial furnace system includes: an industrial furnace, a blower, and a preheater;

[0009] The carbon dioxide capture system includes an induced draft fan, a reboiler, a desorption tower, an absorption tower, and a heat exchanger;

[0010] The biological treatment system includes a buffer tank, a photobioreactor, and a centrifugal dryer;

[0011] The blower is provided with an air suction port and an air discharge pipeline. The air discharge pipeline is divided into two branches. One branch is the combustion-supporting air feed pipeline for the industrial furnace, and the other branch is the air feed pipeline for drying the algal liquid. The combustion-supporting air feed pipeline for the industrial furnace is sequentially connected to the preheater and the industrial furnace. The top of the industrial furnace is provided with a high-temperature flue gas discharge pipeline, and the high-temperature flue gas discharge pipeline is sequentially connected to the preheater, the induced draft fan, the reboiler, and the bottom of the absorption tower;

[0012] The top of the absorption tower is provided with a flue gas discharge pipeline containing NOx, the upper part is provided with an absorbent feed pipeline, and the lower part is provided with a cold rich liquid absorbent discharge pipeline. The cold rich liquid absorbent discharge pipeline is sequentially connected to the reboiler and the desorption tower. The top of the desorption tower is provided with a CO2 discharge pipeline, and the bottom is provided with a hot lean liquid absorbent discharge pipeline. The hot lean liquid absorbent discharge pipeline is sequentially connected to the heat exchanger and the upper part of the absorption tower;

[0013] The flue gas discharge pipeline containing NOx is connected to the photobioreactor. The CO2 discharge pipeline is sequentially connected to the buffer tank and the photobioreactor. The photobioreactor is provided with an algal liquid discharge pipeline, and the algal liquid discharge pipeline is connected to the centrifugal dryer. The air feed pipeline for drying the algal liquid is sequentially connected to the heat exchanger and the centrifugal dryer. The centrifugal dryer is provided with a dried algal powder discharge port.

[0014] The present invention integrates the industrial furnace process, the carbon dioxide capture process, and the microalgae cultivation process to solve the problems of industrial furnace flue gas treatment and the large amount of heat consumption in the above-mentioned conventional chemical absorption method for carbon dioxide capture process and the conventional microalgae cultivation and drying process, and uses the waste heat of the industrial furnace flue gas to provide heat for the carbon dioxide capture process and the microalgae cultivation process.

[0015] According to the present invention, preferably, the device further includes a heating device for providing heat for the reboiler.

[0016] According to the present invention, preferably, the buffer tank is further provided with a product CO2 outlet.

[0017] According to the present invention, preferably, the photobioreactor is further provided with a clean flue gas tail gas discharge port.

[0018] According to the present invention, preferably, the centrifugal dryer is further provided with a dryer tail gas pipeline, and the dryer tail gas pipeline communicates with the atmosphere or communicates with the industrial furnace hearth or the combustion-supporting air feed pipeline.

[0019] According to the present invention, preferably, the photobioreactor is a cultivation device for microalgae plants.

[0020] In the present invention, the photobioreactor is a cultivation device for microalgae plants. After carbon dioxide and nitrogen oxides are introduced into the photobioreactor, the microalgae carry out photosynthesis with the carbon dioxide and nitrogen oxide gases to generate oxygen. After the high-concentration algal liquid enters the centrifugal dryer, it is centrifugally dried to produce algal powder.

[0021] According to the present invention, preferably, both the reboiler and the heat exchanger include a tube side and a shell side.

[0022] According to the present invention, preferably, after the hot lean liquid absorbent discharge pipeline is connected to the heat exchanger, it converges with the absorbent feed pipeline and then is connected to the upper part of the absorption tower.

[0023] The second aspect of the present invention provides a method for flue gas treatment and waste heat utilization. This method is carried out by using the flue gas treatment and waste heat utilization device, and includes the following steps:

[0024] Step I, the high-temperature flue gas generated by the industrial furnace first enters the preheater to exchange heat with the combustion-supporting air of the industrial furnace, obtaining medium-temperature flue gas and the heated combustion-supporting air of the industrial furnace. The heated combustion-supporting air of the industrial furnace enters the industrial furnace, and the medium-temperature flue gas passes through the induced draft fan and enters the reboiler to continue heat exchange, cooling to low-temperature flue gas;

[0025] Step II, the low-temperature flue gas enters the absorption tower from the bottom of the absorption tower, and carbon dioxide is captured by the absorbent entering from the upper part of the absorption tower. The obtained flue gas containing NOx flows out from the top of the absorption tower, and the obtained cold rich liquid absorbent flows into the reboiler from the lower part of the absorption tower and exchanges heat with the medium-temperature flue gas. After being heated to a hot rich liquid absorbent, it enters the desorption tower for carbon dioxide desorption. CO2 is obtained at the top of the tower, and hot lean liquid absorbent is obtained at the bottom of the tower. The hot lean liquid absorbent enters the heat exchanger for heat exchange, and after being cooled to a cold lean liquid absorbent, it returns to the absorption tower;

[0026] Step III: The flue gas containing NOx enters the photobioreactor. After the CO2 is cooled in the buffer tank, it also enters the photobioreactor and undergoes photosynthesis with microalgae to produce oxygen, obtaining a high-concentration algal solution. The high-concentration algal solution is sent to a centrifugal dryer. The drying air of the algal solution exchanges heat with the hot lean liquid absorbent through a heat exchanger, is heated to medium-temperature air, and then enters the centrifugal dryer to heat and centrifugally dry the high-concentration algal solution to produce algal powder.

[0027] In the present invention, the flue gas treatment needs to go through the biological treatment process and the carbon dioxide capture process. After the flue gas passes through the carbon dioxide capture process, through the biological treatment process, the carbon dioxide and nitrogen oxides in the flue gas are treated into oxygen.

[0028] In the present invention, the waste heat utilization is to couple the waste heat of the flue gas in the industrial furnace process with the biological treatment process and the carbon dioxide capture process. The waste heat of the industrial furnace flue gas needs to heat the combustion-supporting air, heat the drying air of the algal solution, and heat the chemical absorbent for carbon dioxide capture.

[0029] The present invention can treat the industrial furnace flue gas into oxygen, high-concentration carbon dioxide, and algal powder without adding additional heat sources and cooling equipment.

[0030] According to the present invention, preferably, the absorbent includes cold lean liquid absorbent and newly added absorbent.

[0031] According to the present invention, preferably, the CO2 generated by the desorption tower is led out through the buffer tank as product CO2.

[0032] In the present invention, the process can produce product carbon dioxide. By controlling the absorption efficiency of the absorption tower, the concentration of CO2 in the flue gas containing NOx can be controlled, thereby adjusting the amount of CO2 entering the photobioreactor from the buffer tank and the amount of product CO2.

[0033] To achieve the above object, the present invention has carried out heat calculation on the overall process.

[0034] According to the present invention, preferably, the temperature of the high-temperature flue gas is 260 - 300 °C, and the temperature of the combustion-supporting air of the industrial furnace is 15 - 30 °C.

[0035] According to the present invention, preferably, the temperature of the combustion-supporting air of the industrial furnace after heating is 180 - 240 °C, and the temperature of the medium-temperature flue gas is 100 - 150 °C.

[0036] According to the present invention, preferably, the tube side of the reboiler passes through the medium-temperature flue gas, and the shell side passes through the cold rich liquid absorbent.

[0037] Preferably, the temperature of the cold rich liquid absorbent is 50 - 80 °C.

[0038] More preferably, the temperature of the hot rich liquid absorbent is 110 - 130°C, and the temperature of the low-temperature flue gas is 60 - 70°C.

[0039] According to the present invention, preferably, the algal liquid drying air flows through the tube side of the heat exchanger, and the hot lean liquid absorbent flows through the shell side.

[0040] Preferably, the temperature of the algal liquid drying air is 15 - 30°C, and the temperature of the hot lean liquid absorbent is 110 - 130°C.

[0041] More preferably, the temperature of the medium-temperature air is 100 - 120°C, and the temperature of the cold lean liquid absorbent is 40 - 60°C.

[0042] The advantages of the present invention are as follows:

[0043] 1. Treat carbon dioxide and nitrogen oxides in the industrial furnace flue gas, and while removing carbon dioxide and nitrogen oxides, produce a profitable algal powder product.

[0044] 2. Couple and utilize the waste heat of the industrial furnace flue gas with carbon dioxide absorption and microalgae drying. On the one hand, it reduces the temperature of the flue gas entering the absorption tower and improves the absorption efficiency. On the other hand, it provides heat for microalgae drying and reduces the cost of microalgae drying.

[0045] 3. Innovate the carbon dioxide chemical absorption process, remove the steam boiler and cooler in the traditional chemical absorption method, reduce costs, and improve energy utilization.

[0046] Other features and advantages of the present invention will be described in detail in the following specific implementation section. Description of the Drawings

[0047] By describing the exemplary embodiments of the present invention in more detail in conjunction with the drawings, the above and other objects, features, and advantages of the present invention will become more apparent. Among them, in the exemplary embodiments of the present invention, the same reference numerals generally represent the same components.

[0048] Figure 1 The schematic diagram of the device for flue gas treatment and waste heat utilization of the present invention is shown.

[0049] Description of the Reference Numerals in the Drawings:

[0050] 1 Industrial furnace, 2 Blower, 3 Preheater, 4 Induced draft fan, 5 Reboiler, 6 Desorption tower, 7 Absorption tower, 8 Buffer tank, 9 Photobioreactor, 10 Centrifugal dryer, 11 Heat exchanger. Specific Embodiments

[0051] The preferred embodiments of the present invention will be described in more detail below. Although the preferred embodiments of the present invention are described below, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein.

[0052] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. They are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0053] Example 1

[0054] This embodiment provides a device for industrial furnace flue gas treatment and waste heat utilization, as Figure 1 shown, including: an industrial furnace system, a carbon dioxide capture system, and a biological treatment system;

[0055] The industrial furnace system includes: an industrial furnace 1 and a preheater 3;

[0056] The carbon dioxide capture system includes a draft fan 4, a reboiler 5, a desorption tower 6, an absorption tower 7, and a heat exchanger 11;

[0057] The biological treatment system includes a buffer tank 8, a photobioreactor 9, and a centrifugal dryer 10;

[0058] A high-temperature flue gas discharge pipeline is provided at the top of the industrial furnace 1, and an industrial furnace combustion-supporting air feed pipeline is provided at the bottom. The industrial furnace combustion-supporting air feed pipeline is first connected to the preheater 3 and then to the bottom of the industrial furnace 1. The high-temperature flue gas discharge pipeline is sequentially connected to the preheater 3, the draft fan 4, the reboiler 5, and the bottom of the absorption tower 7;

[0059] A NOx flue gas discharge pipeline is provided at the top of the absorption tower 7, an absorbent feed pipeline is provided at the upper part, and a cold rich liquid absorbent discharge pipeline is provided at the lower part. The cold rich liquid absorbent discharge pipeline is sequentially connected to the middle of the reboiler 5 and the desorption tower 6. A CO2 discharge pipeline is provided at the top of the desorption tower 6, and a hot lean liquid absorbent discharge pipeline is provided at the bottom. After the hot lean liquid absorbent discharge pipeline is connected to the heat exchanger 11, it converges with the absorbent feed pipeline and then is connected to the upper part of the absorption tower 7. The device further includes a blower 2 for blowing air into the industrial furnace 1 and the centrifugal dryer 10; both the reboiler 5 and the heat exchanger 11 include a tube side and a shell side;

[0060] The NOx flue gas discharge pipeline is connected to the photobioreactor 9. The CO2 discharge pipeline is successively connected to the buffer tank 8 and the photobioreactor 9. The photobioreactor 9 is provided with an algal liquid discharge pipeline, and the algal liquid discharge pipeline is connected to a centrifugal dryer. The centrifugal dryer 10 is provided with an algal liquid drying air feed pipeline. The algal liquid drying air feed pipeline is first connected to a heat exchanger and then connected to the middle part of the centrifugal dryer 10. The photobioreactor is a cultivation device for microalgae plants.

[0061] The method for flue gas treatment and waste heat utilization is carried out by using the device for flue gas treatment and waste heat utilization, and includes the following steps:

[0062] Step I, the high-temperature flue gas generated by the industrial furnace 1 first enters the preheater 3 to exchange heat with the combustion-supporting air of the industrial furnace, obtaining medium-temperature flue gas and heated combustion-supporting air of the industrial furnace. The heated combustion-supporting air of the industrial furnace enters the industrial furnace 1. The medium-temperature flue gas passes through the induced draft fan 4 and enters the reboiler 5 to continue heat exchange, and is cooled to low-temperature flue gas. The temperature of the high-temperature flue gas is 250 °C, the temperature of the combustion-supporting air of the industrial furnace is 20 °C, the temperature of the heated combustion-supporting air of the industrial furnace is 200 °C, and the temperature of the medium-temperature flue gas is 130 °C.

[0063] Step II, the low-temperature flue gas enters the absorption tower 7 from the bottom of the absorption tower 7, and carbon dioxide is captured by the cold lean liquid absorbent entering from the upper part of the absorption tower 7 and the newly added absorbent. The obtained NOx flue gas flows out from the top of the absorption tower 7. The obtained cold rich liquid absorbent flows into the reboiler 5 from the lower part of the absorption tower 7 and exchanges heat with the medium-temperature flue gas. After being heated to a hot rich liquid absorbent, it enters the desorption tower 6 for carbon dioxide desorption. CO2 is obtained at the top of the tower, and the hot lean liquid absorbent is obtained at the bottom of the tower. The hot lean liquid absorbent enters the heat exchanger 11 for heat exchange, and after being cooled to a cold lean liquid absorbent, it returns to the absorption tower 7. The tube side of the reboiler 5 passes the medium-temperature flue gas, and the shell side passes the cold rich liquid absorbent. The temperature of the cold rich liquid absorbent is 65 °C. The temperature of the hot rich liquid absorbent is 120 °C, and the temperature of the low-temperature flue gas is 70 °C.

[0064] Step III, the NOx flue gas enters the photobioreactor 9. After the CO2 is cooled by the buffer tank 8, it also enters the photobioreactor 9 and undergoes photosynthesis with microalgae to produce oxygen, obtaining a high-concentration algal liquid. The high-concentration algal liquid is sent to the centrifugal dryer 10. The algal liquid drying air exchanges heat with the hot lean liquid absorbent through the heat exchanger 11, and after being heated to medium-temperature air, it enters the centrifugal dryer 10 to heat and centrifugally dry the high-concentration algal liquid to produce algal powder. The tube side of the heat exchanger 11 passes the algal liquid drying air, and the shell side passes the hot lean liquid absorbent. The temperature of the algal liquid drying air is 20 °C, and the temperature of the hot lean liquid absorbent is 120 °C. The temperature of the medium-temperature air is 110 °C, and the temperature of the cold lean liquid absorbent is 50 °C.

[0065] Application Example 1

[0066] This application example uses the device and method of Example 1 for flue gas treatment and waste heat utilization.

[0067] A 5MW industrial furnace is adopted. It emits approximately 0.93 million tons of carbon dioxide annually, and the flue gas discharged from the furnace top is about 280°C. After passing through the preheater, the flue gas is cooled to medium-temperature flue gas at about 130°C. The medium-temperature flue gas enters the reboiler again to heat the cold rich liquid absorbent. At this time, the waste heat temperature of the flue gas can approximately provide the heat required for heating 0.11 million tons of cold rich liquid absorbent. The medium-temperature flue gas is cooled to about 70°C and then introduced into the absorption tower 7 for carbon dioxide absorption and capture. Approximately 0.09 million tons of carbon dioxide can be absorbed. After entering the buffer tank 8, the carbon dioxide is introduced into the photobioreactor for carbon fixation treatment. The flue gas passing through the absorption tower 7 has carbon dioxide absorbed, so the remaining nitrogen oxides, nitrogen, and oxygen are introduced into the photobioreactor. During the growth process of microalgae, the nitrogen oxides in the flue gas are consumed, and the remaining nitrogen and oxygen are discharged into the atmosphere.

[0068] The main process of the chemical absorbent is as follows: The cold lean liquid at about 50°C is introduced into the absorption tower for carbon dioxide absorption and capture. After absorption, it becomes the cold rich liquid at about 65°C and is introduced into the reboiler to be heated into the hot rich liquid at about 120°C. The hot rich liquid is further introduced into the desorption tower for carbon dioxide desorption. After becoming the hot lean liquid, it is introduced into the heat exchanger for cooling, and finally mixed with the new cold lean liquid to continue the above process.

[0069] The main process of air is as follows: On the one hand, the ambient air at 20°C is introduced into the preheater to be heated into high-temperature air at about 200°C and introduced into the industrial furnace as combustion-supporting air. On the other hand, it is introduced into the heat exchanger to exchange heat with the hot lean liquid, and the medium-temperature air for algae liquid drying at about 110°C is introduced into the centrifugal dryer. The drying air at about 110°C can approximately dry out 0.05 million tons of algal powder and can approximately treat 0.01 million tons of carbon dioxide.

[0070] In this application example, since the waste heat of the flue gas can provide part of the heat for chemical absorption and algae liquid drying, there are both high-concentration carbon dioxide and dried algal powder in the products.

[0071] Example 2

[0072] The difference between this example and Example 1 is only that the device further includes a heating device for providing heat to the reboiler 5 so that the cold rich liquid is introduced into the reboiler 5 and heated into the hot rich liquid at 120°C.

[0073] Application Example 2

[0074] This application example uses the device and method of Example 2 for flue gas treatment and waste heat utilization.

[0075] Using a 50 MW industrial furnace, it emits approximately 93,000 tons of carbon dioxide per year. The flue gas discharged from the furnace top is about 280 °C. After passing through the preheater, the flue gas is cooled to medium-temperature flue gas at about 130 °C. The medium-temperature flue gas enters the reboiler again to heat the lean solution. At this time, the waste heat temperature of the flue gas can provide approximately the heat required for heating 11,000 tons of absorbent, and the remaining heat needs to be supplemented additionally. The medium-temperature flue gas is cooled to about 70 °C and then introduced into the absorption tower for carbon dioxide absorption and capture. Approximately 83,700 tons of carbon dioxide can be absorbed. After entering the buffer tank, the carbon dioxide is introduced into the photobioreactor for carbon fixation treatment. The flue gas passing through the absorption tower has absorbed carbon dioxide, leaving nitrogen oxides, nitrogen, and oxygen to be introduced into the photobioreactor. During the growth process of microalgae, the nitrogen oxides in the flue gas are consumed, and the remaining nitrogen and oxygen are discharged into the atmosphere.

[0076] The main process of the chemical absorbent is as follows: The cold lean solution at about 50 °C is introduced into the absorption tower for carbon dioxide absorption and capture. After absorption, it becomes the cold rich solution at about 65 °C and is introduced into the reboiler to be heated into the hot rich solution at about 120 °C. The hot rich solution is further introduced into the desorption tower for carbon dioxide desorption. After becoming the hot lean solution, it is introduced into the heat exchanger for cooling, and finally mixed with the new cold lean solution to continue the above process.

[0077] The main process of air is as follows: The ambient air at 20 °C is on the one hand introduced into the preheater to be heated into high-temperature air at about 200 °C and introduced into the industrial furnace as combustion-supporting air. On the other hand, it is introduced into the heat exchanger to exchange heat with the hot lean solution. The medium-temperature air for algal liquid drying at about 110 °C is introduced into the centrifugal dryer. The drying air at about 110 °C can dry approximately 4,600 tons of algal powder and can process approximately 8,400 tons of carbon dioxide.

[0078] In this embodiment, due to the additional heat supplement, the waste heat of the flue gas and the additional heat supplement can all be used to heat the chemical absorbent, and at the same time, all algal liquids can be dried. Therefore, the product is only dried algal powder.

[0079] The above has described the embodiments of the present invention. The above description is exemplary and not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes are obvious to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments.

Claims

1. An apparatus for industrial furnace flue gas treatment and waste heat utilization, characterized in that Comprising: An industrial furnace system, a carbon dioxide capture system, and a biological treatment system; The industrial furnace system includes: an industrial furnace (1), a blower (2), and a preheater (3); The carbon dioxide capture system includes an induced draft fan (4), a reboiler (5), a desorption tower (6), an absorption tower (7), and a heat exchanger (11); The biological treatment system includes a buffer tank (8), a photobioreactor (9), and a centrifugal dryer (10); The blower (2) is provided with an air inlet and an air discharge pipeline. The air discharge pipeline is divided into two branches. One branch is an industrial furnace combustion-supporting air feed pipeline, and the other branch is an algae liquid drying air feed pipeline. The industrial furnace combustion-supporting air feed pipeline is sequentially connected to the preheater (3) and the industrial furnace (1). The top of the industrial furnace (1) is provided with a high-temperature flue gas discharge pipeline. The high-temperature flue gas discharge pipeline is sequentially connected to the preheater (3), the induced draft fan (4), the reboiler (5), and the bottom of the absorption tower (7); The top of the absorption tower (7) is provided with a NOx-containing flue gas discharge pipeline, the upper part is provided with an absorbent feed pipeline, and the lower part is provided with a cold rich liquid absorbent discharge pipeline. The cold rich liquid absorbent discharge pipeline is sequentially connected to the reboiler (5) and the desorption tower (6). The top of the desorption tower (6) is provided with a CO2 discharge pipeline, and the bottom is provided with a hot lean liquid absorbent discharge pipeline. The hot lean liquid absorbent discharge pipeline is sequentially connected to the heat exchanger (11) and the upper part of the absorption tower (7); The NOx-containing flue gas discharge pipeline is connected to the photobioreactor (9). The CO2 discharge pipeline is sequentially connected to the buffer tank (8) and the photobioreactor (9). The photobioreactor (9) is provided with an algae liquid discharge pipeline. The algae liquid discharge pipeline is connected to the centrifugal dryer (10). The algae liquid drying air feed pipeline is sequentially connected to the heat exchanger (11) and the centrifugal dryer (10). The centrifugal dryer (10) is provided with a dried algae powder discharge port.

2. The device for industrial furnace flue gas treatment and waste heat utilization according to claim 1, wherein, The device further includes a heating device for providing heat to the reboiler (5); The buffer tank (8) is further provided with a product CO2 outlet; The photobioreactor (9) is further provided with a clean flue gas tail gas discharge port; The centrifugal dryer (10) is further provided with a dryer tail gas pipeline, and the dryer tail gas pipeline communicates with the atmosphere or communicates with the furnace chamber of the industrial furnace (1) or the combustion-supporting air feed pipeline.

3. The device for industrial furnace flue gas treatment and waste heat utilization according to claim 1, wherein, The photobioreactor (9) is a cultivation device for microalgae plants; Both the reboiler (5) and the heat exchanger (11) include a tube side and a shell side.

4. The device for industrial furnace flue gas treatment and waste heat utilization according to claim 1, wherein, After the hot lean liquid absorbent discharge pipeline is connected to the heat exchanger (11), it converges with the absorbent feed pipeline and then is connected to the upper part of the absorption tower (7).

5. A method for flue gas treatment and waste heat utilization, characterized in that, This method is carried out using the flue gas treatment and waste heat utilization device described in any one of claims 1-4, and includes the following steps: Step I, the high-temperature flue gas generated by the industrial furnace (1) first enters the preheater (3) to exchange heat with the industrial furnace combustion-supporting air, obtaining medium-temperature flue gas and heated industrial furnace combustion-supporting air. The heated industrial furnace combustion-supporting air enters the industrial furnace (1), and the medium-temperature flue gas enters the reboiler (5) through the induced draft fan (4) to continue heat exchange and is cooled to low-temperature flue gas; Step Ⅱ: The low-temperature flue gas enters the absorber (7) from the bottom, and carbon dioxide is captured by the absorbent entering from the upper part of the absorber (7). The obtained flue gas containing NOx flows out from the top of the absorber (7), and the obtained cold rich liquid absorbent flows into the reboiler (5) from the lower part of the absorber (7), exchanges heat with the medium-temperature flue gas, is heated to a hot rich liquid absorbent, and then enters the desorption tower (6) for carbon dioxide desorption. CO2 is obtained at the top of the tower, and the hot lean liquid absorbent is obtained at the bottom of the tower. The hot lean liquid absorbent enters the heat exchanger (11) for heat exchange, is cooled to a cold lean liquid absorbent, and then returns to the absorber (7). Step Ⅲ: The flue gas containing NOx enters the photobioreactor (9). After the CO2 is cooled by the buffer tank (8), it also enters the photobioreactor (9), and photosynthesis occurs with microalgae to produce oxygen, obtaining a high-concentration algal liquid. The high-concentration algal liquid is sent to the centrifugal dryer (10). The drying air of the algal liquid exchanges heat with the hot lean liquid absorbent in the heat exchanger (11), is heated to medium-temperature air, and then enters the centrifugal dryer (10) to heat and centrifugally dry the high-concentration algal liquid to produce algal powder.

6. The method for flue gas treatment and waste heat utilization according to claim 5, wherein, The absorbent includes the cold lean liquid absorbent and the newly added absorbent. The CO2 generated by the desorption tower (6) is led out through the buffer tank (8) as the product CO2.

7. The method for flue gas treatment and waste heat utilization according to claim 5, wherein, The temperature of the high-temperature flue gas is 260 - 300 °C, and the temperature of the combustion-supporting air for the industrial furnace is 15 - 30 °C.

8. The method for flue gas treatment and waste heat utilization according to claim 7, wherein, The temperature of the heated combustion-supporting air for the industrial furnace is 180 - 240 °C, and the temperature of the medium-temperature flue gas is 100 - 150 °C.

9. The method for flue gas treatment and waste heat utilization according to claim 5, wherein, The tube side of the reboiler (5) passes the medium-temperature flue gas, and the shell side passes the cold rich liquid absorbent. Preferably, the temperature of the cold rich liquid absorbent is 50 - 80 °C. More preferably, the temperature of the hot rich liquid absorbent is 110 - 130 °C, and the temperature of the low-temperature flue gas is 60 - 70 °C.

10. The method for flue gas treatment and waste heat utilization according to claim 5, wherein, The tube side of the heat exchanger (11) passes the drying air of the algal liquid, and the shell side passes the hot lean liquid absorbent. Preferably, the temperature of the drying air of the algal liquid is 15 - 30 °C, and the temperature of the hot lean liquid absorbent is 110 - 130 °C. More preferably, the temperature of the medium-temperature air is 100 - 120 °C, and the temperature of the cold lean liquid absorbent is 40 - 60 °C.

Images