System and method for comprehensively utilizing carbon dioxide and low-temperature waste heat of industrial flue gas

Abstract

The invention belongs to the technical field of environmental protection, and particularly relates to an industrial flue gas carbon dioxide and low-temperature waste heat comprehensive utilization system and method.The system comprises a utilization site subsystem and a flue gas treatment subsystem, and the flue gas treatment subsystem absorbs carbon dioxide and smoke dust in industrial flue gas through liquid spraying in an absorption tower; carbon dioxide-containing liquid discharged by an absorption tower is input into the utilization place subsystem in the carbon dioxide and waste heat utilization place, the utilization place subsystem comprises a heat and carbon dioxide release system, and the heat and carbon dioxide release system comprises a liquid storage tank, a water-air heat exchanger and a bubbler. The liquid containing carbon dioxide heats carbon dioxide and air in a waste heat utilization place through the water-air heat exchanger, and the bubbler is arranged in the liquid storage tank and connected with the air blowing system. During operation of the device, a carbon dioxide purification and concentration process does not exist, energy for temperature change or pressure change does not need to be provided, and energy consumption is greatly reduced.

Description

Technical Field

[0001] The present invention belongs to the field of environmental protection technologies, and particularly relates to a system and method for comprehensively utilizing carbon dioxide and low-temperature waste heat in industrial flue gas. Background Art

[0002] Industries such as power, steel, cement, glass, lime, and metallurgy all emit a large amount of industrial flue gas. After processes such as waste heat utilization, dust removal, and desulfurization and denitrification, the temperature of the industrial flue gas is about 100 °C and it contains CO with a concentration of 5-30%. 2 Due to the low temperature and carbon dioxide concentration of the industrial flue gas, it means that the utilization value is low. Therefore, the flue gas is usually directly discharged into the atmosphere and not effectively utilized.

[0003] Currently, the feasible way to utilize the low-temperature waste heat in industrial flue gas is through heat exchange technology to transfer the heat of the flue gas to water. The generated hot water can be supplied to the waste heat boiler in the plant area or used for heating the plant buildings and dormitories. However, since the heat transfer coefficient of the gas is two orders of magnitude smaller than that of water, the heat exchange effect is poor and the heat exchange area needs to be very large, resulting in a large equipment investment. Moreover, the uses of the generated hot water are limited and the value is not high. Therefore, there are not many factories applying this technology. Technologies such as organic Rankine cycle, adsorption refrigeration, and heat pumps can also be used for the utilization of low-temperature waste heat in flue gas, but currently there are also problems such as low system efficiency and high equipment investment.

[0004] There are many technologies for the utilization of carbon dioxide in flue gas. Except for the mineralization technology that can directly utilize the raw flue gas, other carbon dioxide utilization routes, such as being used as a welding shielding gas, making dry ice, synthesizing methanol, synthesizing urea, enhanced oil recovery, etc., all require capturing and purifying carbon dioxide from the flue gas. Since the carbon dioxide concentration in the flue gas is low, the energy consumption and cost for capturing and purification are high, resulting in most of the flue gas carbon dioxide utilization technologies remaining at the demonstration stage and not being industrially applied.

[0005] Using carbon dioxide as a plant gas fertilizer is also one of the carbon dioxide utilization routes. The carbon dioxide concentration suitable for plant growth is about 0.03%-0.2%, which is much lower than the carbon dioxide concentration in the flue gas. In theory, directly introducing the flue gas into the plant greenhouse and diluting it with air can achieve the utilization of carbon dioxide and waste heat efficiently and at low cost. In fact, there are two problems restricting the direct application of the flue gas. One is that although the flue gas has reached the emission standard after dust removal, it still contains a small amount of dust, which has a certain pollution to plants. The other is that even after in-depth treatment to remove various harmful components in the flue gas, once the purification device used fails, the flue gas, as an industrial waste gas, may pollute the crops and cause economic losses. Therefore, currently, the carbon dioxide used in the places for carbon dioxide and waste heat utilization is all high-purity carbon dioxide after capture and purification.

[0006] For example, in patent WO 2010 / 074570 A1, water is used as a medium to absorb carbon dioxide in flue gas. Then, a water pump, a Venturi tube, and a fan are used to create a vacuum environment, enabling carbon dioxide to desorb from the water. After obtaining relatively pure carbon dioxide, it is introduced into the greenhouse for use. According to the second law of thermodynamics, extracting pure carbon dioxide from flue gas with a lower carbon dioxide concentration is a non-spontaneous process that requires energy to regulate the temperature or pressure of the absorption and desorption processes, thereby achieving the concentration of carbon dioxide. Therefore, the energy consumption of the carbon dioxide capture and concentration process is relatively high, resulting in poor economic performance of similar technology applications. Summary of the Invention

[0007] The object of the present invention is to provide a system for comprehensively utilizing carbon dioxide and low-temperature waste heat in industrial flue gas, aiming to solve the technical problems in the prior art that when applying carbon dioxide and waste heat in flue gas to crop greenhouses, the energy consumption for carbon dioxide capture and concentration is relatively high and there is a pollution risk.

[0008] The described system for comprehensively utilizing carbon dioxide and low-temperature waste heat in industrial flue gas includes a utilization site subsystem and a flue gas treatment subsystem. The flue gas treatment subsystem absorbs carbon dioxide and soot in industrial flue gas through liquid spraying in an absorption tower. The carbon dioxide-containing liquid discharged from the absorption tower is input into the utilization site subsystem in the carbon dioxide and waste heat utilization site. The utilization site subsystem includes a heat and carbon dioxide release system, which includes a liquid storage tank, a water-air heat exchanger, and a bubbler. The carbon dioxide-containing liquid heats the air in the carbon dioxide and waste heat utilization site through the water-air heat exchanger. The bubbler is arranged in the liquid storage tank, and the liquid storage tank is provided with an air outlet. The bubbler is connected to a blower system, and the bubbler inputs external air into the carbon dioxide-containing liquid stored in the liquid storage tank. The external air carries the carbon dioxide and heat released from the carbon dioxide-containing liquid into the air in the carbon dioxide and waste heat utilization site.

[0009] Preferably, the sprayer in the absorption tower is connected to a process water pipeline and a circulating makeup water pipeline. The process water pipeline is used to input process water for spraying, and the circulating makeup water pipeline is connected to the water outlet of the utilization site subsystem for recycling the process water.

[0010] Preferably, the drain outlet of the absorption tower is connected to the water inlet of the heat and carbon dioxide release system through a water pump, a solid-liquid separation system, and a water temperature regulation system; temperature sensors and carbon dioxide concentration sensors are provided in the carbon dioxide and waste heat utilization site.

[0011] Preferably, the water temperature adjustment system includes a cold water system, a mixing pipe, a direct transmission pipe, and a flow regulating valve. The mixing pipe and the direct transmission pipe are connected in parallel to the water outlet of the solid-liquid separation system. The mixing pipe is provided with the flow regulating valve and is connected to the water inlet of the cold water system. The direct transmission pipe and the water outlet of the cold water system are connected in parallel to the water inlet of the heat and carbon dioxide release system.

[0012] Preferably, water temperature sensors are provided in both the cold water system and the heat and carbon dioxide release system; the cold water system is one or a combination of a water-air heat exchanger and a water-cooling water heat exchanger for adjusting the water temperature of the system; a water temperature sensor is also provided at the liquid discharge port of the absorption tower.

[0013] Preferably, the flue gas treatment subsystem further includes a chimney, a flue gas pipe, a flue gas regulating valve, a flue gas direct discharge pipe, and a flue gas washing pipe. The flue gas direct discharge pipe and the flue gas washing pipe are connected in parallel to the flue gas pipe for transporting industrial flue gas. The flue gas washing pipe is provided with the flue gas regulating valve and is connected to the flue gas inlet of the absorption tower. The flue gas outlet of the absorption tower and the outlet of the flue gas direct discharge pipe are connected in parallel to the chimney.

[0014] Preferably, a plurality of the liquid storage tanks provided with the bubblers and the water-air heat exchangers are provided, and the liquid storage tanks and the water-air heat exchangers are connected by water pipes to form an adjustment branch. A number of adjustment branches are arranged at different positions in the carbon dioxide and waste heat utilization site. Each adjustment branch is connected in parallel to the main pipeline for transporting water. The air blowing system respectively blows air through a first air supply branch connected to the corresponding liquid storage tank and a second air supply branch connected to the corresponding water-air heat exchanger, and the air supply volume is controlled according to the requirements of each adjustment branch.

[0015] The present invention also provides a method for comprehensively utilizing carbon dioxide and low-temperature waste heat from industrial flue gas. The industrial flue gas is input into a system for comprehensively utilizing carbon dioxide and low-temperature waste heat from industrial flue gas as described above. The amount of industrial flue gas entering the absorption tower is controlled by a flue gas regulating valve. In the absorption tower, process water is used as a medium to directly contact the industrial flue gas, absorbing carbon dioxide and heat in the industrial flue gas; the flue gas that has absorbed carbon dioxide and heat and the flue gas that has not entered the absorption tower enter the factory chimney and are discharged together; the water that has absorbed carbon dioxide and heat is then transported to a solid-liquid separation system by a water pump; the solid-liquid separation system removes the solid particulate matter accumulated in the water; the treated water is processed by a water temperature regulating system to reduce the water temperature to an appropriate temperature and then input into the utilization site subsystem; in the carbon dioxide and waste heat utilization site, a water-air heat exchanger can transfer the heat in the water to the air through indirect heat exchange, only exchanging heat and not carbon dioxide; the air blowing system allows air to directly contact the water with high-concentration carbon dioxide through a bubbler, taking out carbon dioxide and heat, and at the same time regulating the transfer rate of carbon dioxide and heat by adjusting the air flow rate.

[0016] Preferably, in the water temperature regulating system, the water that has absorbed carbon dioxide and heat is respectively transported from a direct transmission pipe and a mixing pipe, and the water volume transported by the mixing pipe is adjusted by a flow regulating valve, allowing part of the water to enter a cooling water system to exchange heat with air or cooling water for cooling; the cooling water system detects whether the water temperature therein has dropped to an appropriate temperature through a water temperature sensor, and after reaching the required water temperature, the water in the cooling water system and the uncooled water in the direct transmission pipe enter a heat and carbon dioxide release system together.

[0017] Preferably, the water from which heat and carbon dioxide have been removed in the utilization site subsystem is transported to the absorption tower for recycling, and a small amount of process water is supplemented during the transportation process to ensure the stable operation of the system.

[0018] The advantages of the present invention are as follows:

[0019] 1. The solution uses water as a direct carrier of carbon dioxide and heat, directly transporting the water containing high-concentration carbon dioxide to the carbon dioxide and waste heat utilization site. There is no carbon dioxide purification and concentration process, and no energy needs to be provided for temperature or pressure change. The entire process proceeds spontaneously, greatly reducing energy consumption.

[0020] 2. When water is used as a carrier for both heat and carbon dioxide simultaneously, the heat contained in the water and the carbon dioxide are related to the temperature and flow rate of the water. Directly introducing the water that has absorbed heat and carbon dioxide into the carbon dioxide and waste heat utilization site cannot accurately control the input heat and carbon dioxide amounts. However, carbon dioxide and waste heat utilization sites such as greenhouse greenhouses have different requirements for heat and carbon dioxide amounts at different time periods. Through the design of the cooling water system and the heat and carbon dioxide release system, the present invention ensures that the heat and carbon dioxide entering the carbon dioxide and waste heat utilization site can be adjusted separately, thereby reliably achieving accurate regulation of flue gas waste heat and carbon dioxide. While meeting the site's requirements for heat and carbon dioxide amounts, it realizes the efficient utilization of industrial flue gas.

[0021] 3. Through the solid-liquid separation system, the accumulation of solid particles in the system is prevented, ensuring the stable operation of the system. At the same time, pollutants such as soot mixed in the water will not spontaneously separate from the water and enter the air under normal pressure, so harmful solid particles in the flue gas can be prevented from entering the carbon dioxide and waste heat utilization site.

[0022] 4. The present invention uses direct contact heat exchange between industrial flue gas and water, greatly improving the heat exchange efficiency, achieving efficient recovery of low-temperature waste heat, and realizing the absorption of carbon dioxide by water. The water containing high-concentration carbon dioxide output by the solid-liquid separation system will not precipitate carbon dioxide due to temperature reduction during the adjustment process of the cooling water system, so the effect of transporting carbon dioxide is reliable. Compared with the heat exchange technology using heat exchangers, the present invention can also reduce equipment costs and improve operating efficiency, achieving three benefits at once. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of a system for comprehensive utilization of industrial flue gas carbon dioxide and low-temperature waste heat in the present invention.

[0024] Figure 2 is Figure 1 A schematic diagram of the heat and carbon dioxide release system in the structure shown.

[0025] The reference numerals in the figure include: 1. Heat and carbon dioxide release system, 2. Blower system, 3. Carbon dioxide and waste heat utilization site, 4. Absorption tower, 5. Chimney, 6. Flue gas regulating valve, 7. Water pump, 8. Solid-liquid separation system, 9. Cooling water system, 10. Flow regulating valve, 11. Circulating makeup water pipeline, 12. Water temperature sensor, 13. Temperature sensor, 14. Carbon dioxide concentration sensor, 15. Liquid storage tank, 16. Water-air heat exchanger. DETAILED DESCRIPTION OF THE INVENTION

[0026] The following will, with reference to the accompanying drawings, further elaborate on the specific embodiments of the present invention through the description of the embodiments, so as to help those skilled in the art have a more complete, accurate and in-depth understanding of the inventive concept and technical solution of the present invention.

[0027] As Figure 1 and Figure 2 shown, the present invention provides a system for comprehensive utilization of carbon dioxide and low-temperature waste heat in industrial flue gas, including a utilization site subsystem and a flue gas treatment subsystem. The flue gas treatment subsystem absorbs carbon dioxide and soot in the industrial flue gas through liquid spraying in the absorption tower 4. The carbon dioxide-containing liquid discharged from the absorption tower 4 is input into the utilization site subsystem in the carbon dioxide and waste heat utilization site 3. The utilization site subsystem includes a heat and carbon dioxide release system 1. The heat and carbon dioxide release system 1 includes a liquid storage tank 15, a water-air heat exchanger 16 and a bubbler. The carbon dioxide-containing liquid heats the air in the carbon dioxide and waste heat utilization site 3 through the water-air heat exchanger 16. The bubbler is arranged in the liquid storage tank 15. The liquid storage tank 15 is provided with an air outlet. The bubbler is connected to a blast system 2 located in the greenhouse. The bubbler inputs external air into the carbon dioxide-containing liquid stored in the liquid storage tank 15. The external air carries the carbon dioxide and heat released from the carbon dioxide-containing liquid into the air in the carbon dioxide and waste heat utilization site 3. In this embodiment, the carbon dioxide and waste heat utilization site 3 is a greenhouse that needs to increase carbon dioxide and temperature.

[0028] The sprayer in the absorption tower 4 is connected to a process water pipeline and a circulating makeup water pipeline 11. The process water pipeline is used to input process water for spraying. The circulating makeup water pipeline 11 is connected to the water outlet of the utilization site subsystem and is used to recycle the process water. In this solution, considering cost and safety, water is used as the liquid for absorbing carbon dioxide. It has low cost and can avoid pollution caused by the liquid itself for absorbing carbon dioxide. At the same time, it can be recycled multiple times to reduce the water consumption.

[0029] The drain outlet of the absorption tower 4 is connected to the water inlet of the heat and carbon dioxide release system 1 via a water pump 7, a solid-liquid separation system 8, and a water temperature regulation system. The water temperature regulation system includes a cooling water system 9, a mixing pipe, a direct transmission pipe, and a flow regulating valve 10. The mixing pipe and the direct transmission pipe are connected in parallel to the outlet of the solid-liquid separation system 8. The flow regulating valve 10 is provided on the mixing pipe and is connected to the water inlet of the cooling water system 9. The direct transmission pipe and the outlet of the cooling water system 9 are connected in parallel to the water inlet of the heat and carbon dioxide release system 1. Water temperature sensors 12 are provided in both the cooling water system 9 and the heat and carbon dioxide release system 1. The cooling water system 9 is one or a combination of a water-air heat exchanger 16 and a water-cooling water heat exchanger, and is used to regulate the water temperature of the system to prevent excessive heat from entering the carbon dioxide and waste heat utilization site 3. A water temperature sensor 12 is also provided at the drain outlet of the absorption tower 4.

[0030] In this way, the solid-liquid separation system 8 can purify the water with high-concentration carbon dioxide and separate the soot in the water. Compared with the prior art system that directly purifies the soot in the collected flue gas or carbon dioxide gas, even when the device for purifying the soot fails, it is very difficult for the soot mixed in the water to be sent into the air in the greenhouse by the gas, so it is not easy to cause pollution to the crops in the greenhouse.

[0031] The flue gas treatment subsystem further includes a chimney 5, a flue gas pipeline, a flue gas regulating valve 6, a flue gas direct discharge pipe, and a flue gas washing pipe. The flue gas direct discharge pipe and the flue gas washing pipe are connected in parallel to the flue gas pipeline for transporting industrial flue gas. The flue gas washing pipe is provided with the flue gas regulating valve 6 and is connected to the flue gas inlet of the absorption tower 4. The flue gas outlet of the absorption tower 4 and the outlet of the flue gas direct discharge pipe are connected in parallel to the chimney 5. In this way, the total amount of carbon dioxide absorbed from the industrial flue gas can be achieved by controlling the total amount of industrial flue gas passing through the absorption tower 4 with the flue gas regulating valve 6.

[0032] The solid-liquid separation system 8 is one or a combination of a hydrocyclone, a filter, a centrifuge, and a sedimentation tank, and is used to remove solid particles in the water to prevent harmful particles from entering the carbon dioxide and waste heat utilization site 3. A temperature sensor 13 and a carbon dioxide concentration sensor 14 are provided in the carbon dioxide and waste heat utilization site 3, so as to detect whether it is necessary to increase the temperature and carbon dioxide concentration of the air in the greenhouse.

[0033] Both the liquid storage tank 15 and the water-air heat exchanger 16 provided with the bubbler can be provided in multiple numbers, and the liquid storage tank 15 and the water-air heat exchanger 16 can be connected by a water pipe to form an adjustment branch. A number of adjustment branches are arranged at different positions in the greenhouse, and each adjustment branch is connected in parallel to the main pipeline for conveying water flow, so that targeted adjustment can also be carried out according to the carbon dioxide concentration and temperature measured at different positions in the greenhouse, and the adjustment branches at different positions can be controlled separately. At this time, the air blowing system 2 respectively blows air through the first air supply branch connected to the corresponding liquid storage tank 15 and the second air supply branch connected to the corresponding water-air heat exchanger 16, and the air supply volume is controlled according to the requirements of the corresponding adjustment branch on each branch.

[0034] Based on the above system, the present invention also provides a method for comprehensively utilizing carbon dioxide and low-temperature waste heat in industrial flue gas, including: the industrial flue gas after sufficient purification of harmful waste gas is input into the above system, and the industrial flue gas is controlled by the flue gas regulating valve 6 to enter the absorption tower 4. In the absorption tower 4, using process water as a medium, it directly contacts the industrial flue gas to absorb carbon dioxide and heat in the industrial flue gas. The flue gas that has absorbed carbon dioxide and heat enters the chimney 5 of the factory together with the flue gas that has not entered the absorption tower 4 and is discharged. The water that has absorbed carbon dioxide and heat is then transported to the solid-liquid separation system 8 by the water pump 7. The solid-liquid separation system 8 removes the solid particles accumulated in the water. The treated water is respectively transported from the direct transmission pipe and the mixing pipe, and the water volume transported through the mixing pipe is adjusted by the flow regulating valve 10, so that part of the water enters the cooling water system 9 to exchange heat with air or cooling water to achieve cooling. The cooling water system 9 detects whether the water temperature in it drops to a suitable temperature through the water temperature sensor 12. After reaching the required water temperature, the water in the cooling water system 9 and the water that has not been cooled in the direct transmission pipe enter the heat and carbon dioxide release system 1 together, and the water temperature sensor 12 is also used here to detect the water temperature of the water entering the heat and carbon dioxide release system 1.

[0035] After that, the water is injected into the liquid storage tank 15 for storage, and a part of the water enters the water-air heat exchanger 16 to heat the air in the carbon dioxide and waste heat utilization place 3 through the heat exchange between water and air. When it is necessary to increase the carbon dioxide concentration in the greenhouse air, this method uses the air blowing system 2 to fill the air in the greenhouse into the liquid storage tank 15 through the bubbler, and the air blowing system 2 can adjust the air blowing volume through the flow meter and the valve. In this way, the air directly contacts the water containing a higher concentration of carbon dioxide, so that the carbon dioxide and heat in the water are released into the filled air and then brought into the greenhouse interior that needs to increase the carbon dioxide concentration and utilize waste heat.

[0036] Among them, the water-air heat exchanger 16 can transfer the heat in the water to the air through indirect heat exchange, only exchanging heat and not carbon dioxide. The blower system 2 can adjust the air flow rate, thereby adjusting the heat transfer rate, and at the same time can also adjust the amount of carbon dioxide carried out by the air, that is, it can adjust the transfer rates of carbon dioxide and heat at the same time. The water-air heat exchanger 16 and the bubbler cooperate with each other to obtain an appropriate amount of carbon dioxide and heat in the carbon dioxide and waste heat utilization field.

[0037] The water from which heat and carbon dioxide have been removed is then transported to the absorption tower 4 for recycling, and a small amount of process water is supplemented during the transportation to ensure the stable operation of the system. A temperature sensor 13 and a carbon dioxide concentration sensor 14 are arranged in the carbon dioxide and waste heat utilization site 3, which can accurately measure the temperature and carbon dioxide concentration in the site. Combined with the water temperature sensor 12 in the system, through feedback control with the flow regulating valve 10 and the water pump 7 in the system, the carbon dioxide and waste heat utilization site 3 can obtain the required heat and carbon dioxide.

[0038] The present invention has been described exemplarily above in conjunction with the accompanying drawings. Obviously, the specific implementation of the present invention is not limited by the above-mentioned manner. As long as various non-substantive improvements are made by adopting the inventive concept and technical solution of the present invention, or the inventive concept and technical solution of the present invention are directly applied to other occasions without improvement, they are all within the protection scope of the present invention.

Claims

1. A system for comprehensive utilization of industrial flue gas carbon dioxide and low-temperature waste heat, characterized in that: The invention comprises a utilization site subsystem and a flue gas treatment subsystem. The flue gas treatment subsystem absorbs carbon dioxide and smoke dust in industrial flue gas by spraying liquid in an absorption tower (4). The carbon dioxide-containing liquid discharged from the absorption tower (4) is input into the utilization site subsystem in a carbon dioxide and waste heat utilization site (3). The utilization site subsystem comprises a heat and carbon dioxide release system (1). The heat and carbon dioxide release system (1) comprises a liquid storage tank (15), a water-air heat exchanger (16) and a bubbler. The carbon dioxide-containing liquid heats the air in the carbon dioxide and waste heat utilization site (3) through the water-air heat exchanger (16). The bubbler is arranged in the liquid storage tank (15). The liquid storage tank (15) is provided with an air outlet. The bubbler is connected to a blast system (2). The bubbler inputs external air into the carbon dioxide-containing liquid stored in the liquid storage tank (15). The external air carries the carbon dioxide and heat precipitated from the carbon dioxide-containing liquid into the air in the carbon dioxide and waste heat utilization site (3).

2. The system for comprehensive utilization of industrial flue gas carbon dioxide and low-temperature waste heat according to claim 1 is characterized in that: The sprayer in the absorption tower (4) is connected to a process water pipeline and a circulating water supply pipeline (11), wherein the process water pipeline is used to input process water for spraying, and the circulating water supply pipeline (11) is connected to the water outlet of the utilization site subsystem for circulating the process water.

3. The system for comprehensive utilization of industrial flue gas carbon dioxide and low-temperature waste heat according to claim 1 is characterized in that: The liquid discharge port of the absorption tower (4) is connected to the water inlet of the heat and carbon dioxide release system (1) via a water pump (7), a solid-liquid separation system (8) and a water temperature adjustment system; a temperature sensor (13) and a carbon dioxide concentration sensor (14) are provided in the carbon dioxide and waste heat utilization place (3).

4. The system for comprehensive utilization of industrial flue gas carbon dioxide and low-temperature waste heat according to claim 3 is characterized in that: The water temperature regulating system comprises a cooling water system (9), a mixing pipe, a direct delivery pipe and a flow regulating valve (10); the mixing pipe and the direct delivery pipe are connected in parallel to the water outlet of the solid-liquid separation system (8); the mixing pipe is provided with the flow regulating valve (10) and is connected to the water inlet of the cooling water system (9); the direct delivery pipe and the water outlet of the cooling water system (9) are connected in parallel to the water inlet of the heat and carbon dioxide release system (1).

5. The system for comprehensive utilization of industrial flue gas carbon dioxide and low-temperature waste heat according to claim 4 is characterized in that: The cooling water system (9) and the heat and carbon dioxide release system (1) are both provided with a water temperature sensor (12); the cooling water system (9) is a combination of one or more water-air heat exchangers (16) and water-cooling water heat exchangers, and is used to adjust the water temperature of the system; the drainage port of the absorption tower (4) is also provided with a water temperature sensor (12).

6. The system for comprehensive utilization of industrial flue gas carbon dioxide and low-temperature waste heat according to claim 1 is characterized in that: The flue gas treatment subsystem also includes a chimney (5), a flue gas duct, a flue gas regulating valve (6), a flue gas straight discharge pipe and a flue gas washing pipe. The flue gas straight discharge pipe and the flue gas washing pipe are connected in parallel to the flue gas duct for conveying industrial flue gas. The flue gas washing pipe is provided with a flue gas regulating valve (6) and is connected to the flue gas inlet of the absorption tower (4). The flue gas outlet of the absorption tower (4) and the outlet of the flue gas straight discharge pipe are connected in parallel to the chimney (5).

7. The system for comprehensive utilization of industrial flue gas carbon dioxide and low-temperature waste heat according to claim 1 is characterized in that: The liquid storage tank (15) and the water-air heat exchanger (16) each having the bubbler therein are provided in plurality, and the liquid storage tank (15) and the water-air heat exchanger (16) are connected via a water pipe to form a regulating branch. The plurality of regulating branches are arranged at different positions in the carbon dioxide and waste heat utilization site (3), and each regulating branch is connected in parallel to a main pipe for conveying water flow. The air blowing system (2) supplies air respectively via a first air supply branch connected to the corresponding liquid storage tank (15) and a second air supply branch connected to the corresponding water-air heat exchanger (16), and the air supply volume is controlled according to the demand of each regulating branch.

8. A method for comprehensive utilization of industrial flue gas carbon dioxide and low-temperature waste heat, characterized in that: The industrial flue gas is input into a system for comprehensive utilization of industrial flue gas carbon dioxide and low-temperature waste heat as described in any one of claims 1 to 7. The amount of industrial flue gas entering the absorption tower (4) is controlled by a flue gas regulating valve (6). In the absorption tower (4), process water is used as a medium to directly contact the industrial flue gas to absorb carbon dioxide and heat in the industrial flue gas; the flue gas that has absorbed carbon dioxide and heat enters the chimney (5) of the factory together with the flue gas that has not entered the absorption tower (4) and is discharged; the water that has absorbed carbon dioxide and heat is transported to the solid-liquid separation system (8) through a water pump (7); the solid-liquid separation system (8) removes solid particles accumulated in the water; the treated water is treated by a water temperature regulating system to reduce the water temperature to a suitable temperature and then input into the utilization site subsystem; In the carbon dioxide and waste heat utilization site (3), the water-air heat exchanger (16) can transfer the heat in the water to the air by indirect heat exchange, exchanging only heat but not carbon dioxide; the blowing system (2) allows the air to directly contact the water with high carbon dioxide concentration through the bubbler, bringing out the carbon dioxide and heat, and at the same time adjusting the transfer speed of carbon dioxide and heat by adjusting the air flow rate.

9. The method for comprehensive utilization of industrial flue gas carbon dioxide and low-temperature waste heat according to claim 8, characterized in that: In the water temperature regulating system, water that has absorbed carbon dioxide and heat is transported from the direct transmission pipe and the mixing pipe respectively. The amount of water transported by the mixing pipe is adjusted by a flow regulating valve (10), so that part of the water enters the cooling water system (9) and exchanges heat with air or cooling water to achieve cooling. The cooling water system (9) detects whether the water temperature therein has dropped to an appropriate temperature through a water temperature sensor (12). When the required water temperature is reached, the water in the cooling water system (9) and the uncooled water in the direct transmission pipe enter the heat and carbon dioxide release system (1) together.

10. The method for comprehensive utilization of industrial flue gas carbon dioxide and low-temperature waste heat according to claim 8, characterized in that: The water in the utilization site subsystem that has been stripped of heat and carbon dioxide is transported to the absorption tower (4) for recycling, and a small amount of process water is added during the transportation process to ensure stable operation of the system.

Images