A system for synergistically recovering water resources and waste heat from flue gas of hydrogen-containing fuel boilers

Abstract

The present invention relates to a system for the coordinated recovery of water resources and waste heat from flue gas of a hydrogen-fueled boiler, belonging to the technical field of resource recovery and environmental protection. The system comprises an ejector, an ejector pressure pump, a return water pump, a demister, a hot water boiler, a three-way mixing regulating valve I, an induced draft fan, an absorption tower, a dilute solution pump, a heat pump liquid storage tank, an economizer, a cooler, a heat pump condenser, a heat pump evaporator, a solution heat exchanger, a three-way mixing regulating valve II, a heat pump compressor, a three-way mixing regulating valve III, a generator, a concentrated solution pump, and a number of connecting pipes, valves, and control elements. The system can be widely applied to the coordinated recovery of water resources and waste heat from flue gas emitted by coal-fired, gas-fired, or biomass-fired power boilers and industrial boilers, kilns in steel and nonferrous metallurgical enterprises, kilns for building materials such as cement and ceramics, and petroleum refining, fertilizer production, and other processes.

Description

Technical Field

[0001] The invention relates to a system for collaboratively recovering water resources and waste heat from flue gas of a hydrogen-containing fuel boiler, belonging to the technical field of resource recovery and environmental protection. Background Art

[0002] Flue gas contains a large amount of waste heat and water resources, which are highly valuable in industrial production. Recovering waste heat from flue gas can reduce energy consumption, improve energy efficiency, and reduce greenhouse gas emissions, which is of great significance to energy conservation, emission reduction, and sustainable development. Furthermore, recovering water from flue gas can reduce water consumption in industrial production, lowering production costs. After treatment, this water can be used for other purposes such as irrigation and cooling. Therefore, the research and application of flue gas water and waste heat recovery technologies have become a key topic in the current field of industrial energy conservation and emission reduction.

[0003] Common waste heat recovery technologies and their advantages and disadvantages: Heat recovery technology recovers heat from flue gas to generate hot water or steam for heating, power generation, and other applications. This technology is simple, easy to implement, and low-cost, making it suitable for industrial production of all sizes. However, heat recovery technology has low efficiency and is easily affected by ambient temperature. Cogeneration technology recovers heat from flue gas to generate electricity and heat, making it a highly efficient waste heat recovery method. This technology offers advantages such as high energy efficiency and reduced greenhouse gas emissions, but it also has high investment costs, is technically challenging, and requires professional maintenance. Adsorption heat recovery technology uses adsorbents to absorb heat from flue gas and then generates heat by heating the adsorbent. This technology offers advantages such as high energy efficiency and environmental friendliness, but the adsorbent has a short lifespan, requires regular replacement, and is expensive to prepare. Common water resource recovery technologies and their advantages and disadvantages: Demisting and dust removal technology extracts water from flue gas through dust and mist removal treatments. This technology is simple, easy to implement, and low-cost, making it suitable for industrial production of all sizes. However, mist removal and dust removal technologies are inefficient and produce low water recovery rates. Membrane separation technology utilizes a semipermeable membrane to filter flue gas, allowing water molecules to pass through while other gases are blocked, thereby recovering water. While this technology offers advantages such as high efficiency and high water recovery, it also comes with high investment costs, a short membrane lifespan, and the need for professional maintenance. Condensation recovery technology reduces the flue gas temperature, condensing water vapor into droplets, thereby recovering water. While this technology offers advantages such as simplicity and low cost, it also offers low condensation efficiency and low water recovery rates.

[0004] The design of the flue gas water and waste heat recovery system requires selection and optimization based on actual conditions. System design must consider factors such as flue gas flow, temperature, humidity, and composition, as well as the quality and intended use of the recovered water. Furthermore, system operational requirements must be formulated and implemented based on actual conditions. For example, regular system operation checks, maintenance, and quality testing of recovered water and waste heat are required. To ensure the proper and efficient operation of the flue gas water and waste heat recovery system, system performance must be evaluated and improved. Evaluation metrics include water recovery, energy recovery, and system operating costs. Improvement measures include optimizing system design, improving operational methods, and replacing high-efficiency equipment. Regular system inspections and maintenance are also necessary to ensure long-term stable operation.

[0005] The technology for the coordinated recovery of water resources and waste heat from flue gases of hydrogen-containing fuel boilers such as natural gas and methanol in the present invention effectively integrates solution dehumidification and dehydration, jet ejection, falling film high-efficiency evaporation, and heat pump energy-saving technologies. The water vapor in the flue gases of hydrogen-containing fuel boilers such as natural gas and methanol is absorbed by a solution with strong water absorption characteristics, so that the moisture and heat of the water vapor are transferred to the solution, and then the moisture and heat are efficiently recovered through heat exchange and regeneration. The present invention makes full use of the pressure energy of the deoxygenated steam inlet of the steam boiler, adopts a steam ejector to reduce the temperature in the solution generator, strengthens the heat exchange in the generator, and realizes the recovery of the working medium and heat of the regenerated steam. In order to further strengthen the heat exchange in the solution regeneration process, the present invention adopts falling film high-efficiency evaporation technology in the generator; in order to enhance the absorption performance of the concentrated solution and to recover the heat of the flue gas to the maximum extent, the heat pump technology is adopted for the boiler with a larger capacity to transfer the heat of the concentrated solution entering the absorption tower to the dilute solution entering the generator. After the boiler flue gas passes through the absorption tower, the flue gas dry bulb temperature can be reduced to below 40 ° C, and the relative humidity can be reduced to below 30-40%. In this way, while taking into account the technical and economic performance of the system, the water resources and waste heat in the flue gas can be maximized. This technology has the characteristics of water saving, energy saving, environmental protection, low cost, and compact structure. Summary of the Invention

[0006] To address the aforementioned problems and shortcomings of the existing technologies, the present invention provides a system for the coordinated recovery of water and waste heat from flue gas from boilers fueled by hydrogen, such as natural gas and methanol. This system is widely applicable to the coordinated recovery of water and waste heat from flue gas emitted by coal-, gas-, or biomass-fired power and industrial boilers; kilns in steel and nonferrous metallurgical enterprises; kilns for building materials such as cement and ceramics; and processes such as oil refining and fertilizer production.

[0007] The present invention is achieved through the following technical solutions.

[0008] A system for synergistically recovering water resources and waste heat from flue gas of a hydrogen-containing fuel boiler, comprising an ejector 1, an ejector pressure pump 2, a return water pump 3, a demister 4, a hot water boiler 5, a three-way mixing regulating valve I6, an induced draft fan 7, an absorption tower 8, a dilute solution pump 9, a heat pump liquid storage tank 10, an economizer 11, a cooler 12, a heat pump condenser 13, a heat pump evaporator 14, a solution heat exchanger 15, a three-way mixing regulating valve II16, a heat pump compressor 17, a three-way mixing regulating valve III18, a generator 19, a concentrated solution pump 20, and several connecting pipes, valves, and control components;

[0009] Flue gas circuit: The flue gas outlet of the hot water boiler 5 is connected to the flue gas inlet of the generator 19 through the flue duct. The flue gas outlet of the generator 19 is connected to the flue gas inlet of the economizer 11. The flue gas outlet of the economizer 11 is connected to the flue gas inlet of the cooler 12. The flue gas outlet pipe of the cooler 12 is connected to the flue gas inlet of the absorption tower 8. The flue gas in the absorption tower 8 passes through the concentrated solution spray layer and enters the demister 4. Finally, it is discharged from the chimney through the flue duct and the induced draft fan 7. The regenerated steam outlet of the generator 19 is connected to the steam inlet of the ejector 1.

[0010] Circulation of concentrated and dilute absorption solutions: The concentrated solution outlet at the bottom of the generator 19 is divided into two paths by the concentrated solution pump 20. One path passes through the solution heat exchanger 15 and the three-way mixing regulating valve II16 in sequence and is mixed with the dilute solution that has become diluted after absorbing the flue gas moisture in the absorption tower 8. Then, it passes through the heat pump evaporator 14 and enters the absorption tower 8, absorbs the heat and condensed water in the flue gas entering the absorption tower 8, and becomes a dilute solution. Then, the dilute solution from the bottom of the absorption tower 8 is connected to the three-way mixing regulating valve II16 through the dilute solution pump 9. The other path of dilute solution passes through the solution heat exchanger 15 and is mixed with another path of concentrated solution coming out of the concentrated solution pump 20 in the three-way mixing regulating valve III18 to form a solution, and then passes through the heat pump condenser 13 and enters the generator 19.

[0011] Condensate return route: The condensate return water passes through the return pump 3 and forms two routes. One route passes through the jet pressure pump 2 and enters the ejector 1 to mix with the steam for injection. The other route is divided into two routes by the three-way mixing regulating valve II16. One route enters the cooler 12 to cool the flue gas to the dew point and then is discharged. After mixing with the other condensate return water, it enters the economizer 11 to absorb heat and finally enters the hot water boiler 5 to be heated into hot water. The hot water enters the heating water distributor for production and domestic use.

[0012] Heat pump cycle: The circulating working medium in the heat pump liquid storage tank 10 is discharged and enters the heat pump evaporator 14, the heat pump compressor 17, and the heat pump condenser 13, and then returns to the heat pump liquid storage tank 10, forming a cycle.

[0013] A system for synergistically recovering water resources and waste heat from flue gas of a hydrogen-containing fuel boiler, comprising a demister 4, a three-way mixing regulating valve I6, an induced draft fan 7, an absorption tower 8, a dilute solution pump 9, an economizer 11, a cooler 12, a solution heat exchanger 15, a three-way mixing regulating valve II16, a three-way mixing regulating valve III18, a generator 19, a concentrated solution pump 20, a deaerator 21, a steam ejector 22, a boiler feed water pump 23, a steam boiler 24, a solution recooler 25, and several connecting pipes, valves, and control components;

[0014] Flue gas circuit: The flue gas outlet of the steam boiler 24 is connected to the flue gas inlet of the generator 19 through the flue duct. The flue gas outlet of the generator 19 is connected to the flue gas inlet of the economizer 11. The flue gas outlet of the economizer 11 is connected to the flue gas inlet of the cooler 12. The flue gas outlet pipe of the cooler 12 is connected to the flue gas inlet of the absorption tower 8. The flue gas in the absorption tower 8 passes through the concentrated solution spray layer and enters the demister 4. Finally, it passes through the flue and the induced draft fan 7 and is discharged from the chimney. The regenerated steam outlet of the generator 19 is connected to the steam ejector 22 and mixed with the steam from the steam boiler 24. The regenerated steam then enters the deaerator 21 and is mixed with the condensate return water to be deoxygenated. After that, it enters the economizer 11 through the boiler feed water pump 23 and finally enters the steam boiler 24 to generate steam. The other steam generated by the steam boiler 24 enters the steam supply cylinder.

[0015] Circulation of concentrated and dilute absorption solutions: The concentrated solution outlet at the bottom of the generator 19 is divided into two paths by the concentrated solution pump 20. One path passes through the three-way mixing regulating valve III18 in sequence and is mixed with the dilute solution that has been diluted after absorbing the flue gas moisture in the absorption tower 8 to form a solution, and then enters the concentrated solution inlet of the generator 19. The other path passes through the solution heat exchanger 15 and is mixed with the dilute solution that has been diluted after absorbing the flue gas moisture in the absorption tower 8 at the three-way mixing regulating valve I6 to form a concentrated solution, and then passes through the boiler feed water pump 25 to enter the concentrated solution inlet of the absorption tower 8.

[0016] Condensate return route: The condensate return water is mixed with soft water through the return pump 3. After mixing, it is divided into two paths through the three-way mixing regulating valve I6. One path enters the cooler 12, and the other path is mixed with the water coming out of the cooler 12 and enters the deaerator 21. The soft water in the soft water make-up tank is connected to the solution recooler 25 through a pump to mix with the condensate return water.

[0017] A system for synergistically recovering water resources and waste heat from flue gas of a hydrogen-containing fuel boiler, comprising a demister 4, a three-way mixing regulating valve I6, an absorption tower 8, a dilute solution pump 9, a heat pump liquid storage tank 10, an economizer 11, a cooler 12, a heat pump condenser 13, a heat pump evaporator 14, a solution heat exchanger 15, a three-way mixing regulating valve II16, a heat pump compressor 17, a three-way mixing regulating valve III18, a generator 19, a concentrated solution pump 20, a deaerator 21, a steam ejector 22, a boiler feed water pump 23, a steam boiler 24, and control components;

[0018] Flue gas circuit: The flue gas outlet of the steam boiler 24 is connected to the flue gas inlet of the generator 19 through the flue, the flue gas outlet of the generator 19 is connected to the flue gas inlet of the economizer 11, the flue gas outlet of the economizer 11 is connected to the flue gas inlet of the cooler 12, and the flue gas outlet pipe of the cooler 12 is connected to the flue gas inlet of the absorption tower 8. The flue gas in the absorption tower 8 passes through the concentrated solution spray layer and enters the demister 4, and finally passes through the flue and the induced draft fan 7 and is discharged from the chimney; the regenerated steam outlet of the generator 19 is connected to the steam ejector 22 and mixed with the steam from the steam boiler 24; then it enters the deaerator 21 and is mixed with the make-up water or condensate return water for deoxygenation, and then enters the economizer 11 through the boiler feed water pump 23, and finally enters the steam boiler 24 to generate steam; the other steam generated by the steam boiler 24 enters the steam supply cylinder;

[0019] Circulation of concentrated and dilute absorption solutions: The concentrated solution outlet at the bottom of the generator 19 is divided into two paths by the concentrated solution pump 20. One path passes through the solution heat exchanger 15 and the three-way mixing regulating valve II16 in sequence, and is mixed with the dilute solution that has become diluted after absorbing the flue gas moisture in the absorption tower 8 to form a concentrated solution. The solution then passes through the heat pump evaporator 14 and enters the absorption tower 8, where it absorbs heat and condensed water in the flue gas entering the absorption tower 8 and becomes a dilute solution. The dilute solution from the bottom of the absorption tower 8 is then connected to the three-way mixing regulating valve II16 through the dilute solution pump 9. The other path of dilute solution passes through the solution heat exchanger 15 and is mixed with another path of concentrated solution coming out of the concentrated solution pump 20 in the three-way mixing regulating valve III18 to form a solution, and then passes through the heat pump condenser 13 and enters the generator 19.

[0020] Makeup water or condensate return route: The makeup water or condensate return water passes through the return water pump to form two routes. One route is pumped into the three-way mixing regulating valve I6 and is divided into two routes. One route is mixed with the water coming out of the cooler 12 and then enters the deaerator 21; the other route enters the cooler 12, and after coming out, it is mixed with the makeup water or condensate and enters the deaerator 21.

[0021] Heat pump cycle: The circulating working medium in the heat pump liquid storage tank 10 is discharged and enters the heat pump evaporator 14, the heat pump compressor 17, and the heat pump condenser 13, and then returns to the heat pump liquid storage tank 10, forming a cycle.

[0022] The absorption solution is LiBr, LiCl, CaCl2, triethylene glycol or diethylene glycol absorption solution.

[0023] The generator 19 is a falling film generator, which is provided with a heat transfer tube a3 inside. A boiler flue gas inlet is provided at the upper end of the side of the falling film generator, and a boiler flue gas outlet is provided at the lower end of the side. A solution inlet is provided at the upper part of the other side of the falling film generator, and a regeneration steam outlet is provided at the top. A guide member a1 is provided on the heat transfer tube a3, and a baffle a4 is provided on the heat transfer tube a3. A liquid storage tank a6 is provided at the bottom of the generator 19, and a concentrated solution outlet is provided at the bottom of the liquid storage tank a6.

[0024] The generator 19 is a heat pipe falling film generator. The heat pipe falling film generator is horizontal, and a flue gas inlet is provided on the upper side of the horizontal end. The horizontal heat pipe falling film generator is provided with a flue gas outlet along the upper horizontal part. A heat pipe b6 with a liquid absorption core is provided inside the heat pipe falling film generator, and a flue gas side baffle b2 and a partition b3 are provided on the heat pipe b6 with a liquid absorption core. A solution inlet is provided on the upper side of the heat pipe falling film generator, and a liquid storage well b5 is provided at the bottom of the heat pipe falling film generator, and a concentrated solution outlet is provided in the liquid storage well b5.

[0025] The ejector 1 recovers the regenerated steam through ejection to produce hot water required for life, thereby reducing the steam generation pressure of the dilute absorption solution and strengthening the generation process.

[0026] The above two three-way valves (three-way mixing regulating valve II16 and three-way mixing regulating valve III18) are used to control the concentration of the solution entering the absorption tower 8 and the generator 19.

[0027] The flue gas is subjected to a dry cooling process in the cooler 12 , and the condensation process of the moisture in the flue gas occurs in the absorption tower 8 .

[0028] The water resource and waste heat synergistic recovery system (I) in flue gas of hydrogen-containing fuel boilers such as natural gas and methanol, such as Figure 1As shown, the working principle is as follows: hot water boiler 5 heats water from economizer 11, generating hot water that enters the heat supply manifold for production and domestic use. Flue gas discharged from hot water boiler 5 enters generator 19, where it transfers heat to the absorption solution to generate regenerative steam. The solution then becomes concentrated. Flue gas from generator 19 enters economizer 11, heating the water supply from cooler 12. Flue gas exiting economizer 11 enters cooler 12, where it is heated and supplied with low-pressure water from the system via a three-way mixing regulating valve I6. The flue gas exiting cooler 12 cools to a temperature near the flue gas dew point. The flue gas then enters absorption tower 8, where it mixes with the concentrated absorption solution, which absorbs heat and condenses water from the flue gas. Finally, the flue gas passes through demister 4 to absorb any remaining moisture, is pressurized by induced draft fan 7, and is discharged into the atmosphere through the chimney. The concentrated absorption solution enters the packing layer in the absorption tower 8, absorbs the condensed water in the flue gas and becomes a dilute absorption solution, which is discharged from the bottom of the absorption tower 8. Then, it is pressurized by the dilute solution pump 9 and enters the solution heat exchanger 15 to exchange heat with the concentrated solution entering the absorption tower. The solution at the outlet of generator 19 is pressurized by concentrated absorption solution pump 20 and divided into two paths. One path is mixed with the dilute absorption solution at the low-temperature outlet of solution heat exchanger 15 in three-way mixing regulating valve II18 to form a solution. The solution then enters generator 19 to absorb heat and precipitate regeneration steam to form a concentrated solution. The regeneration steam is mixed with low-pressure water from the system through jet pressure pump 2 in ejector 1, undergoes heat and mass exchange, and enters the heat supply water separator. After precipitating regeneration steam, the concentrated absorption solution is discharged from the bottom of generator 19; the other path of concentrated absorption solution is cooled by solution heat exchanger 15 and enters three-way mixing valve II16 to mix with the dilute absorption solution discharged from the bottom of absorption tower 8. It then enters heat pump evaporator 14, contacts the heat pump circulating working fluid to cool, and then enters absorption tower 8 to absorb moisture in the flue gas, thus completing the system absorption solution cycle. For this technology, a heat pump cycle is also introduced to achieve heat exchange between dilute and concentrated absorption solutions. The principle is that the circulating working fluid is discharged from the heat pump liquid storage tank 10 and enters the heat pump evaporator 14 to absorb the heat of the concentrated absorption solution entering the absorption tower 8. After that, it enters the heat pump condenser 13 after heat exchange through the heat pump compression 17 to transfer the heat to the absorption solution entering the generator 19, and finally returns to the heat pump liquid storage tank 10. This is a heat pump cycle.

[0029] The water resource and waste heat collaborative recovery system (II) in flue gas of hydrogen-containing fuel boilers such as natural gas and methanol, such as Figure 2As shown, the operating principle is as follows: the steam boiler 24 heats hot water from the economizer 8. One stream of steam enters the steam supply cylinder for production and domestic use, and the other stream enters the steam ejector 22. Flue gas from the steam boiler 4 enters the generator 19, where it transfers heat to the absorption solution to produce regenerated steam and concentrated solution. The flue gas then enters the economizer 8 to heat the steam boiler 24's supply water. The flue gas exiting the economizer 8 enters the cooler 9, which heats the mixed supply water passing through one outlet of the three-way mixing control valve 16. The flue gas temperature exiting the cooler 9 drops to near the flue gas dew point. The flue gas then enters the absorption tower 8 and mixes with the concentrated absorption solution, which absorbs heat and condensed water from the flue gas. Finally, the flue gas passes through the demister 4 to absorb any remaining moisture, is pressurized by the induced draft fan 7, and is discharged to the atmosphere through the chimney. The concentrated absorption solution enters the packing layer of the absorption tower 8, absorbs the condensed water from the flue gas, and becomes a dilute absorption solution, which is discharged from the bottom of the absorption tower 8. It is then pressurized by the dilute solution pump 9 and enters the solution heat exchanger 15 to exchange heat with the concentrated solution entering the absorption tower 8. The concentrated absorption solution at the outlet of the generator 19 is pressurized by the concentrated solution pump 17 and is divided into two paths. One path is mixed with the dilute absorption solution at the low-temperature outlet of the solution heat exchanger 15 in the three-way mixing regulating valve ⅡI18 to become a solution. The solution then enters the generator 19 to absorb heat and precipitate regeneration steam to form a concentrated absorption solution. The regeneration steam is mixed with the steam from the steam boiler 4 in the steam ejector 22, and after heat and mass exchange, it is mixed with the supply water from the cooler 12 and enters the deaerator 21. The hot water with reduced oxygen concentration enters the economizer 8 through the boiler feed water pump 3. The hot water absorbs the heat of the flue gas and is discharged from the economizer 8 to the steam boiler 24. The concentrated absorption solution generated after the regeneration steam is precipitated in the generator 19 is discharged through the bottom of the generator 10; the other path of concentrated absorption solution After the liquid is cooled by the solution heat exchanger 15, it enters the three-way mixing valve II16 and is mixed with the dilute absorption solution discharged from the bottom of the absorption tower 8. It enters the solution recooler 25 and exchanges heat with the water supply from the soft water make-up tank and is cooled. Then it enters the absorption tower 7 to absorb moisture in the flue gas. The water supply from the soft water make-up tank absorbs heat in the solution recooler 13 and is mixed with the condensate return water passing through the water pump system. It enters the three-way mixing regulating valve I6. The mixed water enters the cooler 9 through the three-way mixing regulating valve I6, absorbs the heat of the flue gas in the cooler 9, and the hot water is discharged in the cooler 9. Then the hot water is mixed with the mixed water from the other way passing through the three-way mixing regulating valve I6 and enters the deaerator 1. Together with the hot water from the ejector 2, the system absorption solution cycle is completed.

[0030] The water resource and waste heat synergistic recovery system (III) in flue gas of hydrogen-containing fuel boilers such as natural gas and methanol, such as Figure 3 As shown, the working principle is:

[0031] The steam boiler 24 heats the hot water from the economizer 11 to generate steam, which then flows into the steam supply cylinder for production and domestic use, and then into the steam ejector 22. After the flue gas is discharged from the steam boiler 24, it enters the generator 19 to transfer heat to the absorption solution to produce regenerated steam and concentrated absorption solution. The flue gas then enters the economizer 11 to heat the water supply for the steam boiler 24. The flue gas discharged from the economizer 11 enters the cooler 12 to heat the water supply from the make-up water / condensate tank on one side of the three-way mixing regulating valve I6. The temperature of the flue gas discharged from the cooler 8 drops to near the flue gas dew point. The flue gas then enters the absorption tower 11 to mix with the concentrated absorption solution, which absorbs heat and condensed water from the flue gas. Finally, the flue gas passes through the demister 4 to absorb the remaining moisture, is pressurized by the induced draft fan 12, and is discharged into the atmosphere through the chimney. The concentrated absorption solution enters the packing layer in the absorption tower 11, absorbs the condensed water in the flue gas and becomes a dilute absorption solution, which is discharged from the bottom of the absorption tower 11. It is then pressurized by the dilute solution pump 10 and enters the solution heat exchanger 15 to exchange heat with the concentrated solution entering the absorption tower 11. The concentrated absorption solution at the outlet of the generator 17 is pressurized by the concentrated solution pump 20 and is divided into two paths. One path is mixed with the dilute absorption solution discharged from the low-temperature outlet after heat exchange in the solution heat exchanger 15 in the three-way mixing regulating valve ⅡI18 to become a solution. The solution then enters the generator 19 to absorb heat, precipitate regeneration steam and produce a concentrated solution. The regeneration steam is mixed with the hot water from the steam boiler 24 in the steam ejector 22, and enters the deaerator 1 after heat and mass exchange. The hot water with reduced oxygen concentration enters the economizer 11 through the boiler feed water pump 23. The hot water absorbs the heat of the flue gas and is discharged from the economizer 11 and enters the steam boiler 24. After the regeneration steam is precipitated in the generator 19, the concentrated absorption solution is discharged from the bottom of the generator 19. The other path After cooling through the solution heat exchanger 15, the concentrated absorption solution enters the three-way mixing valve II16 and is mixed with the dilute absorption solution discharged from the bottom of the absorption tower 11. The solution enters the heat pump evaporator 14, contacts the heat pump circulating medium, and cools down before entering the absorption tower 11 to absorb moisture from the flue gas. The water supply from the make-up / return water tank is pumped into the three-way mixing regulating valve I6. The water supply enters the cooler 12 through the three-way mixing regulating valve I6, where it absorbs the heat of the flue gas. The hot water is discharged from the cooler 12, and then the hot water is mixed with the water supply from the other side through the three-way mixing regulating valve I6 and enters the deaerator 1. Together with the hot water from the steam ejector 22, the system absorption solution cycle is completed. For this technology, a heat pump cycle is also introduced to achieve heat exchange between the dilute and concentrated absorption solutions. The principle is that the circulating working fluid is discharged from the heat pump liquid storage tank 9 and enters the heat pump evaporator 14 to absorb the heat of the concentrated absorption solution entering the absorption tower 11. After that, it enters the heat pump condenser 13 after heat exchange through the heat pump compression 16 to transfer the heat to the absorption solution entering the generator 19, and finally returns to the heat pump liquid storage tank 9. This is a heat pump cycle.

[0032] In order to reduce the heat transfer temperature difference in the system and improve the circulation efficiency, the generator adopts falling film high efficiency evaporation technology, in which the generator adopts Figure 4 The falling film generator shown in the figure can also be used when the installation height is limited. Figure 5 The heat pipe falling film generator shown in FIG; (1) for the use of Figure 4 As for the falling film generator shown in the figure, the falling film generator uses a falling film heat transfer tube a3. The high-temperature flue gas discharged from the boiler enters at the upper inlet and enters the outer wall of the falling film heat transfer tube a3. The solution enters at the upper inlet. The dilute solution is evenly distributed on the inner wall surface of the heat transfer tube a3 through the guide piece a1 at the inlet of the falling film heat transfer tube a3 to form a thin liquid film. The liquid film continuously absorbs heat and evaporates during the falling process. The steam rises along the center of the tube to the upper space of the upper tube plate a2 and is discharged through the top steam outlet. The flue gas that needs to be condensed is discharged at the lower outlet after heat exchange through the falling film heat transfer tube. The concentrated solution formed flows along the heat transfer tube a3 to the liquid storage tank a6 and enters the three-way mixing regulating valve through the concentrated solution heat pump for further circulated evaporation. (2) For the use of Figure 5 As for the heat pipe falling film generator shown in the figure, the heat pipe falling film generator adopts a falling film heat pipe b6. The solution is fed into the liquid distribution nozzle b4 in the upper space of the heat pipe falling film generator, and the liquid is evenly distributed on the outer wall of the heat transfer heat pipe b6, forming a thin liquid film. The liquid film continuously absorbs heat and evaporates during the falling process. The steam rises to the upper space of the generator and enters the ejector or through the top outlet. The hot flue gas to be condensed enters the upper space of the hot end of the heat pipe b6 and flows in the outer space of the hot end of the heat pipe b6 to release heat. The condensed flue gas continuously flows down along the outer wall of the hot end of the heat pipe b6 and then flows into the lower outlet of the heat pipe b6 for discharge. The unevaporated solution flows along the heat transfer pipe b6 to the liquid storage well b5 and enters the three-way mixing regulating valve through the concentrated solution heat pump b7 for recirculation and evaporation. In order to strengthen the heat transfer on the flue gas side shown in Figure (4), a heat transfer pipe / heat pipe with fins on the outer surface is used, and a baffle a4 is added on the flue gas side. The heat pipe falling film generator shown in Figure (5) uses a heat pipe with a liquid absorption core, which can be installed horizontally or tilted according to the site conditions.

[0033] The beneficial effects of the present invention are:

[0034] (1) The technology for synergistically recovering water resources and waste heat from flue gas of hydrogen-containing fuel boilers such as natural gas and methanol effectively integrates solution dehumidification and dehydration, jet injection, falling film high-efficiency evaporation, and heat pump energy-saving systems.

[0035] (2) The water vapor in the flue gas of hydrogen-containing fuel boilers such as natural gas and methanol is absorbed by a solution with strong water absorption characteristics, so that the moisture and heat of the water vapor are transferred to the solution, and then the water and heat are efficiently recovered through heat exchange and regeneration.

[0036] (3) The present invention fully utilizes the pressure energy of the deoxygenated steam inlet of the steam boiler, adopts a steam ejector to reduce the temperature in the solution generator, strengthens the heat exchange in the generator, and realizes the recovery of the working medium and heat of the regenerated steam.

[0037] (4) To further enhance heat exchange during the solution regeneration process, the present invention utilizes falling film high-efficiency evaporation technology in the generator. To enhance the absorption performance of the concentrated solution and maximize heat recovery from the flue gas, a heat pump technology is employed in a larger-capacity boiler to transfer the heat from the concentrated solution entering the absorption tower to the dilute solution entering the generator. After the boiler flue gas passes through the absorption tower, the flue gas dry-bulb temperature can be reduced to below 40°C and the relative humidity to below 30-40%. This allows for the efficient recovery and utilization of water resources and waste heat in the flue gas while taking into account both the technical and economic performance of the system. This also completely eliminates condensation and dripping in the boiler flue, as well as the emission of white smoke from the chimney during exhaust.

[0038] (5) The present invention recovers waste heat from flue gas discharged by the boiler in a cascade manner.

[0039] (6) Ejectors are used to provide heating return water. Since the heating recovery temperature is low, less regenerated steam can heat the heating return water, the ejector injection coefficient is reduced, and the heating hot water supply is stable.

[0040] (7) Use heat pump circulation to achieve heat exchange between concentrated and dilute absorption solutions, ensuring that more water in the flue gas is absorbed while producing more regenerated steam.

[0041] (8) It greatly reduces the moisture content in the flue gas, and completely eliminates the phenomenon of condensation, dripping in the boiler flue, and white smoke when the chimney is exhausted. It has the characteristics of water saving, energy saving, environmental protection, low cost, and compact structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 This is a schematic structural diagram of the system (I) for the coordinated recovery of water resources and waste heat from flue gas of hydrogen-containing fuel boilers such as natural gas and methanol;

[0043] Figure 2 This is a schematic structural diagram of the system (II) for the coordinated recovery of water resources and waste heat from flue gas of hydrogen-containing fuel boilers such as natural gas and methanol;

[0044] Figure 3 This is a schematic structural diagram of the system (III) for the coordinated recovery of water resources and waste heat from flue gas of hydrogen-containing fuel boilers such as natural gas and methanol;

[0045] Figure 4 Schematic diagram of the internal structure of the falling film generator of the present invention;

[0046] Figure 5It is a schematic diagram of the internal structure of the heat pipe falling film generator of the present invention.

[0047] Figures 1 to 3 Middle: 1- ejector, 2- jet pressure pump, 3- return water pump, 4- demister, 5- hot water boiler, 6- three-way mixing regulating valve I, 7- induced draft fan, 8- absorption tower, 9- dilute solution pump, 10- heat pump liquid storage tank, 11- economizer, 12- cooler, 13- heat pump condenser, 14- heat pump evaporator, 15- solution heat exchanger, 16- three-way mixing regulating valve II, 17- heat pump compressor, 18- three-way mixing regulating valve III, 19- generator, 20- concentrated solution pump, 21- deaerator, 22- steam ejector, 23- boiler feed water pump, 24- steam boiler, 25- solution recooler; Figure 4 a1-liquid guide, a2-upper tube sheet, a3-falling film heat transfer tube, a4-baffle, a5-lower tube sheet, a6-liquid storage tank; Figure 5 In the middle, b1 is the shell, b2 is the flue gas side baffle, b3 is the partition, b4 is the liquid distribution nozzle, b5 is the liquid storage well, and b6 is the heat pipe with the liquid absorption core. DETAILED DESCRIPTION

[0048] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0049] Example 1

[0050] Application in natural gas hot water boilers: The rated heating capacity of a central heating natural gas hot water boiler is 14MW, the supply and return water temperatures are 95℃ and 70℃, and the flue gas exhaust temperature reaches 120℃.

[0051] like Figure 1 As shown, the water resource and waste heat coordinated recovery system in the flue gas of the hydrogen-containing fuel boiler includes an ejector 1, a jet pressure pump 2, a return water pump 3, a demister 4, a hot water boiler 5, a three-way mixing regulating valve I6, an induced draft fan 7, an absorption tower 8, a dilute solution pump 9, a heat pump liquid storage tank 10, an economizer 11, a cooler 12, a heat pump condenser 13, a heat pump evaporator 14, a solution heat exchanger 15, a three-way mixing regulating valve II16, a heat pump compressor 17, a three-way mixing regulating valve III18, a generator 19, a concentrated solution pump 20 and a number of connecting pipes, valves and control components;

[0052] Flue gas circuit: The flue gas outlet of the hot water boiler 5 is connected to the flue gas inlet of the generator 19 through the flue duct. The flue gas outlet of the generator 19 is connected to the flue gas inlet of the economizer 11. The flue gas outlet of the economizer 11 is connected to the flue gas inlet of the cooler 12. The flue gas outlet pipe of the cooler 12 is connected to the flue gas inlet of the absorption tower 8. The flue gas in the absorption tower 8 passes through the concentrated solution spray layer and enters the demister 4. Finally, it is discharged from the chimney through the flue duct and the induced draft fan 7. The regenerated steam outlet of the generator 19 is connected to the steam inlet of the ejector 1.

[0053] Circulation of concentrated and dilute absorption solutions: The concentrated solution outlet at the bottom of the generator 19 is divided into two paths by the concentrated solution pump 20. One path passes through the solution heat exchanger 15 and the three-way mixing regulating valve II16 in sequence and is mixed with the dilute solution that has become diluted after absorbing the flue gas moisture in the absorption tower 8. Then, it passes through the heat pump evaporator 14 and enters the absorption tower 8, absorbs the heat and condensed water in the flue gas entering the absorption tower 8, and becomes a dilute solution. Then, the dilute solution from the bottom of the absorption tower 8 is connected to the three-way mixing regulating valve II16 through the dilute solution pump 9. The other path of dilute solution passes through the solution heat exchanger 15 and is mixed with another path of concentrated solution coming out of the concentrated solution pump 20 in the three-way mixing regulating valve III18 to form a solution, and then passes through the heat pump condenser 13 and enters the generator 19.

[0054] Condensate return route: The condensate return water passes through the return pump 3 and forms two routes. One route passes through the jet pressure pump 2 and enters the ejector 1 to mix with the steam for injection. The other route is divided into two routes by the three-way mixing regulating valve II16. One route enters the cooler 12 to cool the flue gas to the dew point and then is discharged. After mixing with the other condensate return water, it enters the economizer 11 to absorb heat and finally enters the hot water boiler 5 to be heated into hot water. The hot water enters the heating water distributor for production and domestic use.

[0055] Heat pump cycle: The circulating working medium in the heat pump liquid storage tank 10 is discharged and enters the heat pump evaporator 14, the heat pump compressor 17, and the heat pump condenser 13, and then returns to the heat pump liquid storage tank 10, forming a cycle.

[0056] The absorption solution is LiBr absorption solution, and the circulating working fluid is R404A, R507 or R410A.

[0057] After adopting the technology of the present invention, the exhaust gas temperature is reduced to 50℃, and the water vapor content in the exhaust gas is reduced from 127.5g / kg dry flue gas before the transformation to 40g / kg dry flue gas. The amount of water in the flue gas that can be recovered per hour is about 1.56t / h, and the heat recovered per hour is about 5598584kJ, which is equivalent to 191kgce of standard coal, and the natural gas consumption can be saved by 157.2m per hour. 3 .

[0058] Example 2

[0059] Applied to natural gas steam boiler (without heat pump): The rated evaporation capacity of a natural gas steam boiler in a certain factory is 20t / h (saturated steam), the rated evaporation pressure is 1.6MPa(G), and the flue gas exhaust temperature reaches 120℃.

[0060] like Figure 2As shown, the water resource and waste heat coordinated recovery system in the flue gas of the hydrogen-containing fuel boiler includes a demister 4, a three-way mixing regulating valve I6, an induced draft fan 7, an absorption tower 8, a dilute solution pump 9, an economizer 11, a cooler 12, a solution heat exchanger 15, a three-way mixing regulating valve II16, a three-way mixing regulating valve III18, a generator 19, a concentrated solution pump 20, a deaerator 21, a steam ejector 22, a boiler feed water pump 23, a steam boiler 24, a solution recooler 25 and a number of connecting pipes, valves and control components;

[0061] Flue gas circuit: The flue gas outlet of the steam boiler 24 is connected to the flue gas inlet of the generator 19 through the flue duct. The flue gas outlet of the generator 19 is connected to the flue gas inlet of the economizer 11. The flue gas outlet of the economizer 11 is connected to the flue gas inlet of the cooler 12. The flue gas outlet pipe of the cooler 12 is connected to the flue gas inlet of the absorption tower 8. The flue gas in the absorption tower 8 passes through the concentrated solution spray layer and enters the demister 4. Finally, it passes through the flue and the induced draft fan 7 and is discharged from the chimney. The regenerated steam outlet of the generator 19 is connected to the steam ejector 22 and mixed with the steam from the steam boiler 24. The regenerated steam then enters the deaerator 21 and is mixed with the condensate return water to be deoxygenated. After that, it enters the economizer 11 through the boiler feed water pump 23 and finally enters the steam boiler 24 to generate steam. The other steam generated by the steam boiler 24 enters the steam supply cylinder.

[0062] Circulation of concentrated and dilute absorption solutions: The concentrated solution outlet at the bottom of the generator 19 is divided into two paths by the concentrated solution pump 20. One path passes through the three-way mixing regulating valve III18 in sequence and is mixed with the dilute solution that has been diluted after absorbing the flue gas moisture in the absorption tower 8 to form a solution, and then enters the concentrated solution inlet of the generator 19. The other path passes through the solution heat exchanger 15 and is mixed with the dilute solution that has been diluted after absorbing the flue gas moisture in the absorption tower 8 at the three-way mixing regulating valve I6 to form a concentrated solution, and then passes through the boiler feed water pump 25 to enter the concentrated solution inlet of the absorption tower 8.

[0063] Condensate return route: The condensate return water is mixed with soft water through the return pump 3. After mixing, it is divided into two paths through the three-way mixing regulating valve I6. One path enters the cooler 12, and the other path is mixed with the water coming out of the cooler 12 and enters the deaerator 21. The soft water in the soft water make-up tank is connected to the solution recooler 25 through a pump to mix with the condensate return water.

[0064] The absorption solution is LiBr absorption solution, and the circulating working fluid is R404A.

[0065] After adopting the technology of the present invention, the exhaust gas temperature is reduced to 50℃, and the water vapor content in the exhaust gas is reduced from 127.5g / kg dry flue gas before the transformation to 40g / kg dry flue gas. The amount of water in the flue gas that can be recovered per hour is about 1.56t / h, and the heat recovered per hour is about 5598584kJ, which is equivalent to 191kgce of standard coal, and the natural gas consumption can be saved by 157.2m per hour. 3 .

[0066] Example 3

[0067] Applied to natural gas steam boilers (including heat pumps): The rated evaporation capacity of a natural gas steam boiler in a certain factory is 20t / h (saturated steam), the rated evaporation pressure is 1.6MPa(G), and the flue gas exhaust temperature reaches 120℃.

[0068] like Figure 3 As shown, the water resource and waste heat coordinated recovery system in the flue gas of the hydrogen-containing fuel boiler includes a demister 4, a three-way mixing regulating valve I6, an absorption tower 8, a dilute solution pump 9, a heat pump liquid storage tank 10, an economizer 11, a cooler 12, a heat pump condenser 13, a heat pump evaporator 14, a solution heat exchanger 15, a three-way mixing regulating valve II16, a heat pump compressor 17, a three-way mixing regulating valve III18, a generator 19, a concentrated solution pump 20, a deaerator 21, a steam ejector 22, a boiler feed water pump 23, a steam boiler 24 and control components;

[0069] Flue gas circuit: The flue gas outlet of the steam boiler 24 is connected to the flue gas inlet of the generator 19 through the flue, the flue gas outlet of the generator 19 is connected to the flue gas inlet of the economizer 11, the flue gas outlet of the economizer 11 is connected to the flue gas inlet of the cooler 12, and the flue gas outlet pipe of the cooler 12 is connected to the flue gas inlet of the absorption tower 8. The flue gas in the absorption tower 8 passes through the concentrated solution spray layer and enters the demister 4, and finally passes through the flue and the induced draft fan 7 and is discharged from the chimney; the regenerated steam outlet of the generator 19 is connected to the steam ejector 22 and mixed with the steam from the steam boiler 24; then it enters the deaerator 21 and is mixed with the make-up water or condensate return water for deoxygenation, and then enters the economizer 11 through the boiler feed water pump 23, and finally enters the steam boiler 24 to generate steam; the other steam generated by the steam boiler 24 enters the steam supply cylinder;

[0070] Circulation of concentrated and dilute absorption solutions: The concentrated solution outlet at the bottom of the generator 19 is divided into two paths by the concentrated solution pump 20. One path passes through the solution heat exchanger 15 and the three-way mixing regulating valve II16 in sequence, and is mixed with the dilute solution that has become diluted after absorbing the flue gas moisture in the absorption tower 8 to form a concentrated solution. The solution then passes through the heat pump evaporator 14 and enters the absorption tower 8, where it absorbs heat and condensed water in the flue gas entering the absorption tower 8 and becomes a dilute solution. The dilute solution from the bottom of the absorption tower 8 is then connected to the three-way mixing regulating valve II16 through the dilute solution pump 9. The other path of dilute solution passes through the solution heat exchanger 15 and is mixed with another path of concentrated solution coming out of the concentrated solution pump 20 in the three-way mixing regulating valve III18 to form a solution, and then passes through the heat pump condenser 13 and enters the generator 19.

[0071] Makeup water or condensate return route: The makeup water or condensate return water passes through the return water pump to form two routes. One route is pumped into the three-way mixing regulating valve I6 and is divided into two routes. One route is mixed with the water coming out of the cooler 12 and then enters the deaerator 21; the other route enters the cooler 12, and after coming out, it is mixed with the makeup water or condensate and enters the deaerator 21.

[0072] Heat pump cycle: The circulating working medium in the heat pump liquid storage tank 10 is discharged and enters the heat pump evaporator 14, the heat pump compressor 17, and the heat pump condenser 13, and then returns to the heat pump liquid storage tank 10, forming a cycle.

[0073] The absorption solution is LiBr absorption solution, and the circulating working fluid is R410A.

[0074] After adopting the technology of the present invention, the exhaust gas temperature is reduced to 50℃, and the water vapor content in the exhaust gas is reduced from 127.5g / kg dry flue gas before the transformation to 30g / kg dry flue gas. The amount of water in the flue gas that can be recovered per hour is about 1.74t / h, and the heat recovered per hour is about 6061366kJ, which is equivalent to 207kgce of standard coal. The natural gas consumption can be saved by 170.3m per hour. 3 .

[0075] The above describes the specific embodiments of the present invention in detail with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Various changes can be made within the knowledge of ordinary technicians in this field without departing from the scope of the present invention.

Claims

1. A system for synergistically recovering water resources and waste heat from flue gas of hydrogen-containing fuel boilers, characterized by: It includes an ejector (1), an ejector pressure pump (2), a return water pump (3), a demister (4), a hot water boiler (5), a three-way mixing regulating valve I (6), an induced draft fan (7), an absorption tower (8), a dilute solution pump (9), a heat pump liquid storage tank (10), an economizer (11), a cooler (12), a heat pump condenser (13), a heat pump evaporator (14), a solution heat exchanger (15), a three-way mixing regulating valve II (16), a heat pump compressor (17), a three-way mixing regulating valve III (18), a generator (19), a concentrated solution pump (20), and a number of connecting pipes, valves, and control elements; Flue gas circuit: The flue gas outlet of the hot water boiler (5) is connected to the flue gas inlet of the generator (19) through the flue duct, the flue gas outlet of the generator (19) is connected to the flue gas inlet of the economizer (11), the flue gas outlet of the economizer (11) is connected to the flue gas inlet of the cooler (12), the flue gas outlet pipe of the cooler (12) is connected to the flue gas inlet of the absorption tower (8), the flue gas in the absorption tower (8) passes through the concentrated solution spray layer and enters the demister (4), and finally passes through the flue duct and the induced draft fan (7) and is discharged from the chimney; the regeneration steam outlet of the generator (19) is connected to the steam inlet of the ejector (1); Circulation of concentrated and dilute absorption solutions: the concentrated solution outlet at the bottom of the generator (19) is divided into two paths through the concentrated solution pump (20). One path passes through the solution heat exchanger (15) and the three-way mixing regulating valve II (16) in sequence and is mixed with the diluted solution that has been diluted after absorbing the flue gas moisture in the absorption tower (8). Then, it passes through the heat pump evaporator (14) and enters the absorption tower (8), absorbs the heat and condensed water in the flue gas entering the absorption tower (8), and becomes a dilute solution. Then, the dilute solution from the bottom of the absorption tower (8) is connected to the three-way mixing regulating valve II (16) through the dilute solution pump (9). The other path of dilute solution passes through the solution heat exchanger (15) and is mixed with another path of concentrated solution coming out of the concentrated solution pump (20) in the three-way mixing regulating valve III (18) to form a solution, and then passes through the heat pump condenser (13) and enters the generator (19); Condensate return route: Condensate return water passes through the return water pump (3) to form two routes. One route passes through the jet pressure pump (2) and enters the ejector (1) to mix with steam and inject. The other route is divided into two routes through the three-way mixing regulating valve II (16). One route enters the cooler (12) to cool the flue gas to the dew point and then is discharged. After mixing with the other route of condensate return water, it enters the economizer (11) to absorb heat and finally enters the hot water boiler (5) to be heated into hot water. The hot water enters the heat supply water distributor for production and life use. Heat pump cycle: The circulating working fluid in the heat pump liquid storage tank (10) is discharged and enters the heat pump evaporator (14), the heat pump compressor (17), the heat pump condenser (13), and then returns to the heat pump liquid storage tank (10), forming a cycle.

2. A system for synergistically recovering water resources and waste heat from flue gas of hydrogen-containing fuel boilers, characterized by: It includes a demister (4), a three-way mixing regulating valve I (6), an induced draft fan (7), an absorption tower (8), a dilute solution pump (9), an economizer (11), a cooler (12), a solution heat exchanger (15), a three-way mixing regulating valve II (16), a three-way mixing regulating valve III (18), a generator (19), a concentrated solution pump (20), a deaerator (21), a steam ejector (22), a boiler feed water pump (23), a steam boiler (24), a solution recooler (25), and a number of connecting pipes, valves, and control components; Flue gas line: The flue gas outlet in the steam boiler (24) is connected to the flue gas inlet of the generator (19) through the flue, the flue gas outlet in the generator (19) is connected to the flue gas inlet of the economizer (11), the flue gas outlet of the economizer (11) is connected to the flue gas inlet of the cooler (12), the flue gas outlet pipe of the cooler (12) is connected to the flue gas inlet of the absorption tower (8), the flue gas in the absorption tower (8) passes through the concentrated solution spray layer and enters the demister (4), and finally passes through the flue and the induced draft fan (7) and is discharged from the chimney; another regeneration steam outlet is connected to the steam ejector (22) and mixed with the steam from the steam boiler (24); then enters the deaerator (21) and is mixed with the condensate return water to be deoxidized, and then enters the economizer (11) through the boiler feed water pump (23), and finally enters the steam boiler (24) to generate steam; the other steam generated by the steam boiler (24) enters the steam supply cylinder; Circulation of concentrated and dilute absorption solutions: The concentrated solution outlet at the bottom of the generator (19) is divided into two paths by a concentrated solution pump (20). One path passes through a three-way mixing regulating valve III (18) and is mixed with the diluted solution that has been diluted after absorbing the flue gas water vapor in the absorption tower (8) to form a solution, and then enters the concentrated solution inlet of the generator (19). The other path passes through a solution heat exchanger (15) and is mixed with the diluted solution that has been diluted after absorbing the flue gas water vapor in the absorption tower (8) at a three-way mixing regulating valve II (16) to form a concentrated solution, and then passes through a solution recooler (25) and enters the concentrated solution inlet of the absorption tower (8). Condensate return route: The condensate return water is mixed with soft water through the return pump (3). After mixing, it is divided into two paths through the three-way mixing regulating valve I (6). One path enters the cooler (12), and the other path is mixed with the water from the cooler (12) and enters the deaerator (21). The soft water in the soft water supply tank is connected to the solution recooler (25) through a pump to mix with the condensate return water.

3. A system for synergistically recovering water resources and waste heat from flue gas of hydrogen-containing fuel boilers, characterized by: It includes a demister (4), a three-way mixing regulating valve I (6), an absorption tower (8), a dilute solution pump (9), a heat pump liquid storage tank (10), an economizer (11), a cooler (12), a heat pump condenser (13), a heat pump evaporator (14), a solution heat exchanger (15), a three-way mixing regulating valve II (16), a heat pump compressor (17), a three-way mixing regulating valve III (18), a generator (19), a concentrated solution pump (20), a deaerator (21), a steam ejector (22), a boiler feed water pump (23), a steam boiler (24) and a control element; Flue gas line: The flue gas outlet in the steam boiler (24) is connected to the flue gas inlet of the generator (19) through the flue, the flue gas outlet in the generator (19) is connected to the flue gas inlet of the economizer (11), the flue gas outlet of the economizer (11) is connected to the flue gas inlet of the cooler (12), the flue gas outlet pipe of the cooler (12) is connected to the flue gas inlet of the absorption tower (8), the flue gas in the absorption tower (8) passes through the concentrated solution spray layer and enters the demister (4), and finally passes through the flue and the induced draft fan (7) and is discharged from the chimney; the regenerated steam outlet of the generator (19) is connected to the steam ejector (22) and mixed with the steam from the steam boiler (24); then it enters the deaerator (21) and is mixed with the feed water or condensate return water to be deoxidized, and then enters the economizer (11) through the boiler feed water pump (23), and finally enters the steam boiler (24) to generate steam; the other steam generated by the steam boiler (24) enters the steam supply cylinder; Circulation of concentrated and dilute absorption solutions: the concentrated solution outlet at the bottom of the generator (19) is divided into two paths through the concentrated solution pump (20). One path passes through the solution heat exchanger (15), the three-way mixing regulating valve II (16), and is mixed with the diluted solution that has been diluted after absorbing the flue gas moisture in the absorption tower (8) to form a concentrated solution. After passing through the heat pump evaporator (14), it enters the absorption tower (8), absorbs the heat and condensed water in the flue gas entering the absorption tower (8), and becomes a dilute solution. Then, the dilute solution from the bottom of the absorption tower (8) is connected to the three-way mixing regulating valve II (16) through the dilute solution pump (9). The other path of dilute solution passes through the solution heat exchanger (15) and is mixed with the other path of concentrated solution coming out of the concentrated solution pump (20) in the three-way mixing regulating valve III (18) to form a solution, and then passes through the heat pump condenser (13) and enters the generator (19); Makeup water or condensate return route: The makeup water or condensate return water passes through the return water pump to form two routes. One route is pumped into the three-way mixing regulating valve I (6) and is divided into two routes. One route is mixed with the water coming out of the cooler (12) and then enters the deaerator (21); the other route enters the cooler (12), and after exiting, it is mixed with the makeup water or condensate and enters the deaerator (21). Heat pump cycle: The circulating working fluid in the heat pump liquid storage tank (10) is discharged and enters the heat pump evaporator (14), the heat pump compressor (17), the heat pump condenser (13), and then returns to the heat pump liquid storage tank (10), forming a cycle.

4. The system for synergistically recovering water resources and waste heat from flue gas of hydrogen-containing fuel boilers according to claim 3 is characterized in that: The absorption solution is LiBr, LiCl, CaCl2, triethylene glycol or diethylene glycol absorption solution.

5. The system for synergistically recovering water resources and waste heat from flue gas of hydrogen-containing fuel boilers according to claim 3 is characterized in that: The generator (19) is a falling film type generator. A heat transfer tube a3 is provided inside the falling film type generator. A boiler flue gas inlet is provided at the upper end of the side of the falling film type generator, and a boiler flue gas outlet is provided at the lower end of the side. A solution inlet is provided at the upper end of the other side of the falling film type generator, and a regeneration steam outlet is provided at the top. A flow guide a1 is provided on the heat transfer tube a3, and a baffle a4 is provided on the heat transfer tube a3. A liquid storage tank a6 is provided at the bottom of the generator (19), and a concentrated solution outlet is provided at the bottom of the liquid storage tank a6.

6. The system for synergistically recovering water resources and waste heat from flue gas of hydrogen-containing fuel boilers according to claim 3 is characterized in that: The generator (19) is a heat pipe type falling film generator. The heat pipe type falling film generator is horizontal. A flue gas inlet is provided on the upper side of the horizontal end. A flue gas outlet is provided along the upper horizontal portion of the horizontal heat pipe type falling film generator. A heat pipe b6 with a liquid wick is provided inside the heat pipe type falling film generator. A flue gas side baffle b2 and a partition b3 are provided on the heat pipe b6 with a liquid wick. A solution inlet is provided on the upper side of the heat pipe type falling film generator. A liquid storage well b5 is provided at the bottom of the heat pipe type falling film generator. A concentrated solution outlet is provided in the liquid storage well b5.

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