Flue gas dehumidification and waste heat utilization system

Abstract

The present application relates to a kind of flue gas dehumidification and waste heat utilization system, by absorbing flue gas waste heat, the dehumidification dilute solution is heated to generate the dehumidification concentrated solution with dehumidification function, and the water in solution evaporation produces a large amount of high-temperature steam, the dehumidification concentrated solution is transported to the water in the absorption tower absorption desulfurization wet flue gas, eliminate white smoke plume, and the steam produced is used to heat unit condensate, reduce the coal consumption of unit, the system can eliminate wet plume while maximize the purpose of saving power coal consumption.

Description

TECHNICAL FIELD

[0001] The present application relates to a flue gas dehumidification and waste heat utilization system, belonging to the technical field of flue gas treatment. BACKGROUND

[0002] The deep utilization of flue gas waste heat discharged by coal-fired boilers and the effective treatment of wet flue gas discharged after wet flue gas desulfurization are important links in energy saving and emission reduction, and have been concerned by people all the time. An efficient waste heat recycling system is the key, aiming to recover waste heat and solve the problem of wet plume emission. At present, there are generally two ways to recover waste heat for controlling wet plume emission:

[0003] MGGH (Mitsubishi Gas-gas Heater) flue gas heat exchange system is used to recover flue gas waste heat to control wet plume emission. The MGGH system mainly consists of a pre-heat recovery device and a post-reheater. The flue gas at the outlet of the air preheater releases heat in the pre-heat recovery device, and the heat is transferred to the heating medium water. The heated heating medium water flows to the post-reheater through a pipeline to release heat to the low-temperature wet flue gas after desulfurization, so as to increase the temperature of the flue gas and eliminate the wet plume. The cooling heating medium water flows to the pre-heat recovery device through a pipeline to absorb heat and increase the temperature, completing a cycle.

[0004] Flue gas condensation reheating technology is used to control wet plume emission. The saturation moisture content of the flue gas after desulfurization is reduced by cooling and condensation technology, and the flue gas heating technology is used to increase the flue gas temperature to eliminate the wet plume emission. Compared with the MGGH system, the flue gas condenser is added, which is mainly arranged in front of the reheater. In addition to recovering flue gas waste heat, this method is also beneficial to reducing the emission of water vapor and condensable particulate matter mainly composed of SO3. The condensation reheating technology has a wider range of use and can better adapt to low-temperature and high-humidity environments.

[0005] The above-mentioned method recovers flue gas waste heat to directly heat the wet flue gas at the outlet of the desulfurization device. While keeping the absolute moisture content of the wet flue gas unchanged, the relative moisture content is reduced, so that the flue gas enters an unsaturated state after being heated (i.e. the relative humidity of the flue gas after being heated is less than the saturation humidity after being heated), thereby achieving the purpose of eliminating white smoke. Flue gas heating technology can increase the exhaust gas height and promote the diffusion of pollutants carried by flue gas in the atmosphere, but direct heating of clean flue gas cannot reduce the emission of water vapor and condensable particulate matter mainly composed of SO3, and cannot achieve the purpose of water saving and consumption reduction. On the contrary, it may even increase energy consumption and form negative environmental benefits.

[0006] The above-mentioned condensation reheating technology adds a condensation system compared with direct heating, which can reduce the emission of water vapor and condensable particulate matter mainly composed of SO3. However, due to the limited temperature reduction range of the condenser, the amount of recovered condensate water is small, and the system is more complex. The recovered waste heat is only used to heat the wet flue gas at the outlet of the desulfurization device, and has not been fully utilized, which cannot achieve the purpose of reducing the coal consumption of the unit.

[0007] In addition, the coal-fired boiler flue gas heat recovery equipment usually operates in a high-concentration dust environment and is continuously eroded by fly ash particles, which inevitably causes wear of the heat recovery equipment heat exchange tubes. The conventional heat exchange tubes have limited thickness, and as the wear intensifies, the tubes will eventually be perforated. In the traditional flue gas heat recovery equipment, the cooling medium in all the tubes is connected, and once a tube leaks, the cooling medium will continuously leak into the flue gas, causing serious problems such as dust accumulation and blockage. From the actual operation of the equipment, it can be found that the conventional flue gas heat recovery equipment has a serious problem of local tube bundle wear, which causes heat exchange tube bundle leakage and leads to problems such as dust accumulation and blockage of the heat exchanger, affecting the safe operation of the flue gas system. The maintenance cycle of the conventional heat recovery equipment is about 2-3 years, which seriously affects the normal operation of the unit and brings great trouble to the operation of the coal-fired unit, and also increases the maintenance cost.

[0008] The invention patent with publication number "CN109745841A" discloses a flue gas condensation two-stage solution dehumidification and reheating system and method for white smoke elimination. The system includes an ultra-low temperature economizer, a flue gas condensation water recovery device, a dilute solution dehumidification tower, a dilute solution storage device, a dilute solution pump, a concentrated solution dehumidification tower, a concentrated solution storage device, a concentrated solution pump, a solution regenerator, an intermediate solution pump, a flue gas heater, a chimney, and other equipment. The system condenses the wet flue gas by using the main condensation water, recycles the water and waste heat in the flue gas, removes the water, dust, and other substances in the flue gas through two-stage solution dehumidification, heats the flue gas using the driving steam waste heat of the solution dehumidification, and then discharges the flue gas through the chimney, achieving water recovery and ultra-clean flue gas discharge.

[0009] The severity of white smoke has an exponential relationship with the environmental temperature and humidity. However, in the above-mentioned scheme, the solution regenerator always maintains a unique working power, and the concentration of the generated regenerated solution is also uniform. Therefore, the solution concentration cannot be intelligently adjusted according to the environment, which leads to incomplete white smoke elimination or excessive power consumption, failing to achieve the purpose of energy saving and emission reduction. SUMMARY

[0010] To solve the problems in the prior art, the present application provides a flue gas dehumidification and waste heat utilization system.

[0011] The technical scheme of the present application is as follows:

[0012] On the one hand, the present application provides a flue gas dehumidification and waste heat utilization system, which includes a boiler, an electric precipitator, a wet desulfurization tower, an absorption tower, and a chimney arranged in sequence along the flue gas direction, and further includes a heat pipe type dehumidification solution regenerating device, a dehumidification solution storage tank, a dehumidification solution-cooling water heat exchanger, and a plurality of circulating pumps.

[0013] The heat pipe of the heat pipe type dehumidification solution regenerating device is connected with the boiler exhaust port and the electric dust collector flue gas inlet respectively, the heat pipe type dehumidification solution regenerating device is connected with the dehumidification solution storage tank through the circulating pump, one side of the dehumidification solution storage tank is connected with the dehumidification solution-cooling water heat exchanger through the circulating pump, the dehumidification solution-cooling water heat exchanger is connected with the absorption tower, and the absorption tower is connected with the heat pipe type dehumidification solution regenerating device through the circulating pump.

[0014] As the preferred embodiment of the present application, the heat pipe type dehumidification solution regenerating device is also connected with the steam-condensate water heat exchanger inlet;

[0015] The steam-condensate water heat exchanger is used for receiving water vapor generated after the dehumidification dilute solution is heated and evaporated, and exchanging heat with condensate water of the heating unit, after the heat exchange, the water vapor is condensed into liquid water and enters the drain buffer tank through the connected drain valve.

[0016] As the preferred embodiment of the present application, the heat pipe type dehumidification solution regenerating device includes a cover plate, a plurality of heat pipes, a water vapor discharge pipe, a dehumidification dilute solution inlet pipe, a dehumidification solution generating tank, a vacuumizing pipe, a filter, a vacuum pump, a plurality of nozzles, a concentrated solution outlet pipe and a frame;

[0017] One end of the plurality of heat pipes is arranged in the frame according to a fixed interval to form a heat conduction module, the other end of the plurality of heat pipes penetrates from the bottom to the top of the dehumidification solution generating tank, and the cover plate covers the top of the dehumidification solution generating tank.

[0018] The dehumidification dilute solution inlet pipe penetrates from the outer wall of one side of the dehumidification solution generating tank to the inner wall of the other side of the dehumidification solution generating tank, and the part of the dehumidification dilute solution inlet pipe in the dehumidification solution generating tank is uniformly arranged with a plurality of nozzles;

[0019] The top of one side wall of the dehumidification solution generating tank is connected with the water vapor discharge pipe, the bottom of the other side wall is connected with the concentrated solution outlet pipe, the top of the other side wall is connected with one end of the vacuumizing pipe, the other end of the vacuumizing pipe is connected with the inlet of the filter, and the outlet of the filter is connected with the vacuum pump.

[0020] As the preferred embodiment of the present application, the heat pipe includes a heat pipe head, a heat pipe heat releasing section, an adiabatic partition, a heat pipe heat absorbing section and a heat transfer working medium.

[0021] The heat pipe head is arranged at the end of the heat pipe penetrating into the top of the dehumidification solution generating tank, the heat pipe heat releasing section is the part of the heat pipe in the dehumidification solution generating tank, the heat pipe heat absorbing section is the part of the heat pipe in the frame, the heat transfer working medium is in the heat pipe, and the adiabatic partition is arranged between the frame and the dehumidification solution generating tank.

[0022] As a preferred embodiment of the present application, a demister is arranged at the top of the absorption tower, a dry flue gas exhaust port is arranged at the outlet of the demister, and the dry flue gas exhaust port is connected with a chimney; a plurality of nozzles are arranged below the demister for spraying the wet flue gas with a dehumidification solution.

[0023] As a preferred embodiment of the present application, the dehumidification solution-cooling water heat exchanger is connected with the plurality of nozzles.

[0024] As a preferred embodiment of the present application, the dehumidification solution-cooling water heat exchanger is provided with a cooling water inlet and a cooling water outlet, the dehumidification solution in the dehumidification solution storage tank is cooled by the cooling water input through the cooling water inlet, and the heated cooling water is discharged through the cooling water outlet.

[0025] As a preferred embodiment of the present application, the flue gas dehumidification and waste heat utilization system further comprises a first controller, a second controller, a third controller, a fourth controller and a fifth controller.

[0026] A flue gas humidity sensor is arranged between the dry flue gas exhaust port and the chimney, and the flue gas humidity sensor is electrically connected with the first controller.

[0027] A first solution concentration sensor is arranged in the dehumidification solution storage tank, and the first solution concentration sensor is electrically connected with the second controller.

[0028] A second solution concentration sensor is arranged between the heat pipe type dehumidification solution regeneration device and the inlet of the dehumidification solution storage tank, and the second solution concentration sensor is electrically connected with the third controller.

[0029] A third solution concentration sensor is arranged between the absorption tower and the inlet of the heat pipe type dehumidification solution regeneration device, and the third solution concentration sensor is electrically connected with the fourth controller.

[0030] The first controller calculates the optimal flue gas emission humidity based on the ambient temperature and humidity, the flue gas humidity sensor collects the humidity of the dry flue gas discharged from the dry flue gas exhaust port in real time and transmits it to the first controller, the first controller determines whether the current dry flue gas humidity is the optimal flue gas emission humidity, if not, the concentration required for the current dehumidification solution is calculated based on the error, and the second controller, the third controller and the fourth controller are input respectively.

[0031] The fourth controller receives the dehumidification solution concentration obtained by the third solution concentration sensor, compares it with the concentration required for the dehumidification solution, and controls the heat pipe type dehumidification solution regeneration device to change the concentration of the dehumidified dilute dehumidification solution.

[0032] As a preferred embodiment of the present application, the dehumidification solution storage tank is provided with a dehumidifier storage device and a stirrer, and the dehumidifier storage device is electrically connected with the fifth controller.

[0033] The third controller receives the dehumidification solution concentration obtained by the second solution concentration sensor, and compares the dehumidification solution concentration with the required concentration of the dehumidification solution; if the dehumidification solution concentration does not meet the concentration requirement, an error signal is transmitted to the fifth controller, and the fifth controller controls the dehumidifier storage device to add a corresponding amount of dehumidifier to the dehumidification solution storage tank according to the error signal.

[0034] In another aspect, the application also provides a flue gas dehumidification and waste heat utilization method, comprising the following steps:

[0035] The dehumidification concentrated solution stored in the dehumidification solution storage tank is input into the absorption tower after being cooled by the dehumidification solution-cooling water heat exchanger, the cooled dehumidification concentrated solution in the absorption tower is converted into dehumidification dilute solution after dehumidifying the desulfurization wet flue gas input from the wet desulfurization tower, and the dehumidification dilute solution is input into the heat pipe type dehumidification solution regeneration device, while dry flue gas after dehumidification is discharged.

[0036] The heat pipe type dehumidification solution regeneration device absorbs boiler flue gas waste heat and inputs the boiler flue gas into the wet desulfurization tower, the heat pipe type dehumidification solution regeneration device heats and evaporates the input dehumidification dilute solution by absorbing the boiler flue gas waste heat to obtain dehumidification concentrated solution, and then the dehumidification concentrated solution is input into the dehumidification solution storage tank for storage.

[0037] The application has the following beneficial effects:

[0038] 1. The application has the characteristics of high efficiency and low energy consumption, through the synergistic effect of various devices in the system, the wet smoke plume is eliminated at the same time, the waste heat is fully utilized, the purposes of smoke gas "white elimination", energy saving and consumption reduction are achieved, and in addition, the inlet temperature of the electric precipitator can be reduced, the dust removal efficiency of the electric precipitator is improved, and the leakage problem caused by wear of traditional heat recovery equipment is solved.

[0039] 2. The application generates dehumidification concentrated solution with dehumidification function by heating the dehumidification dilute solution by absorbing the waste heat of flue gas, and a large amount of high-temperature steam is generated by evaporation of water in the solution. The dehumidification concentrated solution is transported to the absorption tower to absorb the water in the desulfurized wet flue gas, and the white smoke plume is eliminated. The generated steam is used to heat the condensate water of the unit, and the coal consumption of the unit is reduced. The system can maximize the purpose of saving coal consumption while eliminating the wet smoke plume.

[0040] 3. The heat pipe type dehumidification solution regeneration device of the application adopts a new type of heat pipe bundle as the main unit, which mainly consists of a dehumidification solution generating tank, a heat pipe, an adiabatic partition, a spraying system and the like. During the operation of the heat pipe type dehumidification solution regeneration device, the dehumidification solution and the flue gas are respectively heat-exchanged in the upper and lower parts of the heat pipe type dehumidification solution regeneration device, the flue gas and the dehumidification solution are independently operated, and the leakage problem caused by wear of the flue gas side pipe is avoided.

[0041] 4、The present application adopts the dehumidification concentrated solution to remove the moisture in the wet flue gas, which not only has high dehumidification efficiency, but also can effectively filter the residual nitrogen oxides and sulfides, and realizes the ultra-clean emission of flue gas.

[0042] 5、The present application obtains the environmental parameters in real time through the sensors and the controller, and adjusts the dehumidification intensity in real time according to the environmental changes, realizes the intelligent white elimination and waste heat utilization, and has the characteristics of high efficiency and low energy consumption. BRIEF DESCRIPTION OF DRAWINGS

[0043] Figure 1 It is a system structure schematic view of the present application;

[0044] Figure 2 It is a heat pipe type dehumidification solution regeneration device structure schematic view;

[0045] Figure 3 It is a heat pipe type dehumidification solution regeneration device heat pipe structure schematic view;

[0046] Figure 4 It is a solution dehumidification working principle schematic view.

[0047] 1, heat pipe type dehumidification solution regeneration device, 2, absorption tower, 2-1, mist eliminator, 2-2, dehumidification dilute solution, 3, dehumidification solution-cooling water heat exchanger, 4-1, first circulating pump, 4-2, second circulating pump, 4-2, third circulating pump, 5, dehumidification solution storage tank, 5-1, stirrer, 5-2, dehumidifier storage device, 6, steam-condensate water heat exchanger, 7, trap, 8, trap buffer tank, 1-1, cover plate, 1-2, heat pipe, 1-3, water vapor discharge pipe, 1-4, dehumidification solution inlet pipe, 1-5, dehumidification concentrated solution, 1-7, vacuum pipe, 1-8, filter, 1-9, vacuum pump, 1-10, nozzle, 1-11, concentrated solution outlet pipe, 1-12, frame, 1-21, heat pipe head, 1-22, heat pipe heat release section, 1-23, heat insulation partition, 1-24, heat pipe heat absorption section, 1-25, heat transfer working medium, 9-1, flue gas humidity sensor, 9-2, first solution concentration sensor, 9-3, second solution concentration sensor, 9-4, third solution concentration sensor, 10-1, first controller, 10-2, second controller, 10-3, third controller, 10-4, fourth controller, 10-5, fifth controller. DETAILED DESCRIPTION

[0048] With reference to the accompanying drawings, the technical solutions in the embodiments of the present application will be clearly and completely described, obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of the present application.

[0049] Embodiment one:

[0050] Referring to Figure 1 , including a boiler, an electric precipitator, a wet desulfurization tower, an absorption tower 2 and a chimney are sequentially arranged along the flue gas direction, and further comprising a heat pipe type dehumidification solution regeneration device 1, a dehumidification solution-cooling water heat exchanger 3, a dehumidification solution storage tank 5, and a plurality of circulating pumps;

[0051] The heat exchange pipes of the heat pipe type dehumidification solution regeneration device 1 are respectively connected with the boiler exhaust port, the flue gas inlet of the electric precipitator, the heat pipe type dehumidification solution regeneration device 1 is connected with the dehumidification solution storage tank 5 through the third circulating pump 4-3, the other side of the dehumidification solution storage tank 5 is connected with the dehumidification solution-cooling water heat exchanger 3 through the first circulating pump 4-1, the dehumidification solution-cooling water heat exchanger 3 is connected with the absorption tower 2, and the second circulating pump 4-2 of the absorption tower is connected with the heat pipe type dehumidification solution regeneration device.

[0052] As a preferred embodiment of the present embodiment, the heat pipe type dehumidification solution regeneration device 1 is further connected with the inlet of the steam-condensate water heat exchanger 6;

[0053] The steam-condensate water heat exchanger 5 is used for receiving water vapor generated after the dehumidification dilute solution is heated and evaporated, and exchanging heat with the condensate water of the heating unit, after the heat exchange, the water vapor is condensed into liquid water and enters the drain buffer tank 8 through the connected drain valve 7.

[0054] Referring to Figure 2 , the heat pipe type dehumidification solution regeneration device 1 comprises a cover plate 1-1, a plurality of heat pipes 1-2, a water vapor discharge pipe 1-3, a dehumidification dilute solution inlet pipe 1-4, a dehumidification solution generation tank 1-5, a vacuumizing pipe 1-7, a filter 1-8, a vacuum pump 1-9, a plurality of nozzles 1-10, a concentrated solution outlet pipe 1-11, and a frame 1-12;

[0055] One end of the plurality of heat pipes 1-2 is arranged in the frame 1-12 according to fixed intervals to form a heat conduction module, the other end of the plurality of heat pipes 1-2 penetrates from the bottom to the top of the dehumidification solution generation tank 1-5, and the cover plate 1-1 covers the top of the dehumidification solution generation tank 1-5;

[0056] The dehumidification dilute solution inlet pipe 1-4 is penetrated from the outer wall of one side of the dehumidification solution generating box 1-5 to the inner wall of the other side of the dehumidification solution generating box 1-5, and the part of the dehumidification dilute solution inlet pipe 1-4 inside the dehumidification solution generating box 1-5 is uniformly arranged with a plurality of nozzles 1-10;

[0057] The side wall top of the dehumidification solution generating box 1-5 is connected with the water vapor discharge pipe 1-3, the bottom of the other side wall is connected with the concentrated solution outlet pipe 1-11, the top of the other side wall is connected with one end of the vacuum pump 1-7, the other end of the vacuum pump 1-7 is connected with the inlet of the filter 1-8, and the outlet of the filter 1-8 is connected with the vacuum pump 1-9.

[0058] As a preferred embodiment of the present embodiment, referring to Figure 3 , the heat pipe 1-2 comprises a heat pipe head 1-21, a heat pipe heat releasing section 1-22, an adiabatic partition plate 1-23, a heat pipe heat absorbing section 1-24, and a heat transfer medium 1-25.

[0059] The heat pipe head 1-21 is arranged at one end of the heat pipe 1-2 penetrating to the top of the dehumidification solution generating box 1-5, the heat pipe heat releasing section 1-22 is the part of the heat pipe inside the dehumidification solution generating box 1-5, the heat pipe heat absorbing section 1-24 is the part of the heat pipe inside the frame 1-12, the heat transfer medium 1-25 is inside the heat pipe 1-2, and the adiabatic partition plate 1-23 is arranged between the frame 1-12 and the dehumidification solution generating box 1-5.

[0060] Specifically, during the operation of the heat pipe type dehumidification solution regenerating device, the dehumidification solution and the flue gas are respectively heat exchanged at the upper and lower parts of the heat pipe type dehumidification solution regenerating device 1, the adiabatic partition plate 1-23 of the heat pipe type dehumidification solution regenerating device 1 is above the heat pipe heat releasing section 1-22, and is below the heat pipe heat absorbing section 1-24, the flue gas and the dehumidification solution are independently operated and do not interfere with each other.

[0061] The heat pipe heat transfer process: the heat pipe is vacuumized, the high-temperature flue gas flows through the heat pipe heat absorbing section 1-24, so that the heat transfer medium 1-25 in the heat pipe heat absorbing section 1-24 absorbs heat and changes from liquid to gas to evaporate, the generated steam rises along the inside of the heat pipe to the heat pipe heat releasing section 1-22, the steam releases heat to transfer heat to the dehumidification solution 1-6, the temperature of the dehumidification solution rises, the excess moisture evaporates, and the heat transfer medium 1-25 in the heat pipe evaporated upwards is condensed to liquid and then flows to the heat pipe heat absorbing section 1-24 again under the action of gravity to absorb heat again, so as to realize the transfer of heat, so that the concentration of the dehumidification solution is increased, and the outlet temperature of the flue gas is reduced.

[0062] The heat pipe type dehumidification solution regeneration device generates dehumidification concentrated solution and steam process: the dehumidification dilute solution 2-2 enters from the dehumidification solution inlet pipe 1-4, is uniformly sprayed on the surface of the heat pipe heat releasing section 1-22 by the nozzle 1-10, and the water in the dehumidification dilute solution 2-2 continuously evaporates after being heated to finally form the dehumidification concentrated solution 1-6 gathered at the bottom of the dehumidification solution generating tank 1-5. The water vapor in the solution after evaporation is discharged through the water vapor discharge pipe 1-3 for further waste heat utilization.

[0063] In addition, the heat pipe type dehumidification solution regeneration device is provided with a vacuum pump 1-9, the air in the dehumidification solution generating tank 1-5 is continuously extracted through the vacuum extraction pipe 1-7 and the filter 1-8, the vacuum degree in the dehumidification solution generating tank 1-5 is improved, and the evaporation rate is accelerated. The heat pipe type dehumidification solution regeneration device adopts a frame 1-12 to form a module with a plurality of heat pipes 1-2, each heat pipe is provided with a heat pipe head 1-21, the heat pipe head 1-21 can be a welded seal or can be repeatedly opened, the heat pipe heat absorbing section 1-24 can be a light pipe or can be provided with an expanded heat receiving surface to increase the heat exchange area, the cover plate 1-1 can be opened during the operation of the heat pipe type dehumidification solution regeneration device to check the heat exchange performance of the heat pipe, and the maintenance is convenient.

[0064] In the embodiment, the dehumidification concentrated solution 1-6 is transported to the dehumidification solution storage tank 5 through the third circulating pump 4-3, the dehumidification solution storage tank 5 is provided with a dehumidifier storage device 5-2, and the dehumidifier can be added to adjust the concentration of the dehumidification solution according to the application, and is provided with a stirrer 5-1 to uniformly stir the dehumidification solution.

[0065] The dehumidification concentrated solution 1-6 in the dehumidification solution storage tank 5 is transported to the absorption tower 2 through the first circulating pump 4-1, the top of the absorption tower 2 is provided with a demister 2-1, the outlet of the demister 2-1 is provided with a dry flue gas exhaust port, and the dry flue gas exhaust port is connected with a chimney; the dehumidification solution-cooling water heat exchanger 3 is provided with a cooling water inlet and a cooling water outlet, the cooling water input through the cooling water inlet cools the dehumidification solution input from the dehumidification solution storage tank 5, and the cooling water outlet discharges the heated cooling water.

[0066] The outlet of the dehumidification solution-cooling water heat exchanger 3 penetrates from the middle of the outer wall of one side of the absorption tower 2 to the middle of the inner wall of the other side, and the part of the dehumidification solution-cooling water heat exchanger 3 in the absorption tower 2 is uniformly arranged with a plurality of nozzles 1-10, the dehumidification concentrated solution 1-6 is atomized by the nozzles 1-10, the contact area between the dehumidification concentrated solution 1-6 and the flue gas is increased, the moisture in the flue gas is more fully absorbed, the dehumidified flue gas flows through the demister 2-1 arranged at the top of the absorption tower 2, and finally becomes dry flue gas and is discharged, achieving the purpose of "white elimination".

[0067] The dehumidification concentrated solution 1-6 absorbs moisture of flue gas and is converted into dehumidification dilute solution 2-2, which is transported to the heat pipe type dehumidification solution regenerator 1 by the second circulating pump 4-2 to be converted into dehumidification concentrated solution 1-6 by reabsorbing waste heat of flue gas, and the process is repeated.

[0068] The dehumidification concentrated solution 1-6 absorbs heat during the generation process and its temperature rises, and its moisture absorption capacity decreases. In order to improve the moisture absorption capacity of the solution, the dehumidification concentrated solution 1-6 needs to be heat-exchanged with the dehumidification solution-cooling water heat exchanger 3 before entering the absorption tower 2 to reduce the temperature of the dehumidification concentrated solution 1-6.

[0069] The heat pipe type dehumidification solution regenerator 1 is also connected with the inlet of the steam-condensate water heat exchanger 6; the steam-condensate water heat exchanger 6 is used to receive water vapor generated by heating and evaporation of the dehumidification dilute solution 2-2 and exchange heat with condensate water of the heating unit, and the water vapor after heat exchange is condensed into liquid water and enters the drain buffer tank 8 through the connected drain valve 7, so as to reduce the steam consumption of the unit and save coal consumption.

[0070] The dehumidification solution is mainly concentrated solution of lithium bromide (LiBr), lithium chloride (LiCl), calcium chloride (CaCl2), triethylene glycol (TEG) and the like which has a moisture absorption function;

[0071] Referring to Figure 4 , the working principle of solution dehumidification is to realize the absorption of moisture by using the difference between the surface vapor pressure of the solution and the water vapor partial pressure in the environment. As Figure 4 shown is the process of dehumidification of the salt solution to the moisture in the environment, when the surface vapor pressure of the salt solution ( ) is less than the water vapor partial pressure of the air ( ), the water vapor in the air automatically migrates to the salt solution until the pressure of the two reaches balance.

[0072] The dehumidification of wet flue gas is based on this principle, and the concentrated solution with a moisture absorption function is used as a dehumidifier, and the water vapor partial pressure difference between the flue gas and the dehumidification solution is used as a driving force to realize the migration of water by directly contacting the flue gas, and the dehumidification process of the flue gas is completed.

[0073] As a preferred embodiment of the present embodiment, the heat pipe type dehumidification solution regenerator 1 is also connected with the inlet of the steam-condensate water heat exchanger 6;

[0074] The steam-condensate water heat exchanger 6 is also connected with the drain valve 7 for receiving water vapor generated by heating and evaporation of the dehumidification dilute solution 2-2 and exchanging heat with condensate water of the heating unit, and the water vapor after heat exchange is condensed into liquid water and enters the drain buffer tank 8.

[0075] As a preferred embodiment of the present embodiment, the flue gas dehumidification and waste heat utilization system further comprises a first controller 10-1, a second controller 10-2, a third controller 10-3, a fourth controller 10-4 and a fifth controller 10-5;

[0076] The flue gas humidity sensor 9-1 is electrically connected with the first controller 10-1;

[0077] The first solution concentration sensor 9-2 is arranged in the dehumidification solution storage tank 5 and electrically connected with the second controller 10-2;

[0078] The second solution concentration sensor 9-3 is arranged between the heat pipe type dehumidification solution regenerator 1 and the inlet of the dehumidification solution storage tank 5 and electrically connected with the third controller 10-3;

[0079] The third solution concentration sensor 9-4 is arranged between the absorption tower 2 and the inlet of the heat pipe type dehumidification solution regenerator 1 and electrically connected with the fourth controller 10-4;

[0080] The first controller 10-1 calculates the optimal flue gas emission humidity based on the ambient temperature and humidity, the flue gas humidity sensor 9-1 collects the humidity of the dry flue gas discharged from the dry flue gas exhaust port in real time and transmits it to the first controller 10-1, the first controller 10-1 judges whether the current dry flue gas humidity is the optimal flue gas emission humidity, if not, calculates the required concentration of the current dehumidification solution based on the error and inputs it into the second controller 10-2, the third controller 10-3 and the fourth controller 10-4 respectively;

[0081] The fourth controller 10-4 receives the dehumidification solution concentration obtained by the third solution concentration sensor 9-4 and compares it with the required concentration of the dehumidification solution to control the heat pipe type dehumidification solution regenerator 1 to change the concentration of the dehumidified dilute solution.

[0082] As a preferred embodiment of the present embodiment, the dehumidifier storage device 5-2 is electrically connected with the fifth controller 10-5;

[0083] The third controller 10-3 receives the dehumidification solution concentration obtained by the second solution concentration sensor 9-3 and compares it with the required concentration of the dehumidification solution, if the dehumidification solution concentration does not meet the concentration requirement, transmits an error signal to the fifth controller 10-5, and the fifth controller 10-5 controls the dehumidifier storage device 5-2 to add a corresponding amount of dehumidifier according to the error signal.

[0084] The lower the ambient temperature and the greater the ambient humidity, the more likely it is to form white smoke, and the severity of the white smoke is exponentially related to the ambient temperature and humidity. The severity of the white smoke from the chimney generally presents as: winter > autumn ≈ spring > summer. Therefore, in order to more accurately control white smoke emissions, recover waste heat from flue gas, and reduce the operating cost of the entire system, the system is equipped with an intelligent management system that can adjust the moisture absorption intensity in a timely manner according to environmental temperature, humidity, and other parameters. For example, in winter, when the temperature is low and white smoke is most likely to occur, the flue gas humidity sensor 9-1 transmits the flue gas humidity to the first controller 10-1 in real time, and the first controller 10-1 calculates and analyzes the optimal flue gas emission humidity based on the detected ambient temperature and humidity. If the emission flue gas humidity is too high and the white smoke elimination effect does not meet the expected result, it indicates that the moisture absorption capacity of the solution needs to be enhanced. At this time, the third solution concentration sensor 9-4 and the fourth controller 10-4 calculate and analyze the dilute solution after dehumidification, reduce the size of the droplets of the dilute solution sprayed on the heat pipe heat dissipation section, increase the heat exchange area, and increase the water evaporation amount. The concentrated solution after regeneration is calculated and analyzed by the second solution concentration sensor 9-3 and the third controller 10-3 to determine whether it meets the concentration requirement. If the dehumidification solution concentration needs to be further adjusted, a certain amount of dehumidifier is automatically added by the fifth controller 10-5 to control the dehumidifier storage device 5-2. Finally, the first solution concentration sensor 9-2 and the second controller 10-2 calculate and analyze to obtain the final accurate dehumidification concentrated solution. Conversely, the system automatically adjusts to reduce the concentration of the dehumidification solution. Finally, the white smoke is eliminated intelligently.

[0085] Example Two

[0086] A flue gas dehumidification and waste heat utilization method, comprising the following steps:

[0087] The dehumidification concentrated solution 1-6 stored in the dehumidification solution storage tank 5 is cooled by the dehumidification solution-cooling water heat exchanger 3 and the cooling water, and then input into the absorption tower 2. The cooled dehumidification concentrated solution 1-6 in the absorption tower 2 dehumidifies the desulfurized wet flue gas input from the wet desulfurization tower and is converted into dehumidification dilute solution 2-2, and the dehumidification dilute solution 2-2 is input into the heat pipe type dehumidification solution regeneration device 1, while the dry flue gas after dehumidification is discharged.

[0088] The heat pipe type dehumidification solution regeneration device 1 absorbs the waste heat of the boiler flue gas and inputs the boiler flue gas into the wet desulfurization tower. The heat pipe type dehumidification solution regeneration device 1 heats and evaporates the input dehumidification dilute solution 2-2 by absorbing the waste heat of the boiler flue gas to obtain dehumidification concentrated solution 1-6, which is then stored in the dehumidification solution storage tank 5.

[0089] The above merely illustrates the embodiments of the present application, and does not limit the patent scope of the present application, and any equivalent structure or equivalent process transformation, or direct or indirect application in other related technical fields, which are made by using the content of the present application specification and drawings, are also included in the patent protection scope of the present application.

Claims

1. A flue gas dehumidification and waste heat utilization system, comprising a boiler, an electric dust collector, a wet desulfurization tower, an absorption tower and a chimney which are sequentially arranged along the flue gas direction, characterized in that, Further comprising a heat pipe type dehumidification solution regenerating device, a dehumidification solution storage tank, a dehumidification solution-cooling water heat exchanger, and several circulating pumps; The heat pipe type dehumidification solution regenerating device is connected with a boiler exhaust outlet and an electric dust collector flue gas inlet respectively, and is connected with the dehumidification solution storage tank through the circulating pumps; the other side of the dehumidification solution storage tank is connected with the dehumidification solution-cooling water heat exchanger through the circulating pumps; The dehumidification solution-cooling water heat exchanger is connected with the absorption tower, and the absorption tower is connected with the heat pipe type dehumidification solution regenerating device through the circulating pumps; The heat pipe type dehumidification solution regenerating device is further connected with a steam-condensate water heat exchanger inlet; The steam-condensate water heat exchanger is used for receiving water vapor generated after heating and evaporation of the dehumidification dilute solution and exchanging heat with condensate water of a heating unit, and the water vapor after heat exchange is condensed into liquid water and enters a drain buffer tank through a connected drain valve. The heat pipe type dehumidification solution regenerating device comprises a cover plate, several heat pipes, a water vapor discharge pipe, a dehumidification dilute solution inlet pipe, a dehumidification solution generating tank, a vacuumizing pipe, a filter, a vacuum pump, several nozzles, a concentrated solution outlet pipe, and a frame. One end of the several heat pipes is arranged in the frame according to a fixed interval to form a heat conduction module, the other end of the several heat pipes penetrates from the bottom to the top of the dehumidification solution generating tank, and the cover plate covers the top of the dehumidification solution generating tank. The dehumidification dilute solution inlet pipe penetrates from the outer wall of one side of the dehumidification solution generating tank to the inner wall of the other side of the dehumidification solution generating tank, and the part of the dehumidification dilute solution inlet pipe inside the dehumidification solution generating tank is uniformly arranged with the several nozzles. The top of the side wall of the dehumidification solution generating tank is connected with the water vapor discharge pipe, the bottom of the other side wall is connected with the concentrated solution outlet pipe, the top of the other side wall is connected with one end of the vacuumizing pipe, the other end of the vacuumizing pipe is connected with the inlet of the filter, and the outlet of the filter is connected with the vacuum pump.

2. The flue gas dehumidification and waste heat utilization system according to claim 1, characterized in that, The heat pipe comprises a heat pipe head, a heat pipe heat releasing section, an adiabatic partition, a heat pipe heat absorbing section, and a heat transfer working medium. The heat pipe head is arranged at the end of the heat pipe penetrating into the top of the dehumidification solution generating tank, the heat pipe heat releasing section is the part of the heat pipe inside the dehumidification solution generating tank, the heat pipe heat absorbing section is the part of the heat pipe inside the frame, the heat transfer working medium is inside the heat pipe, and the adiabatic partition is arranged between the frame and the dehumidification solution generating tank.

3. The flue gas dehumidification and waste heat utilization system according to claim 1, characterized in that, A demister is arranged at the top inside the absorption tower, a dry flue gas exhaust outlet is arranged at the outlet of the demister, and the dry flue gas exhaust outlet is connected with a chimney; a plurality of nozzles are arranged below the demister and used for spraying the dehumidification solution to the wet flue gas.

4. The flue gas dehumidification and waste heat utilization system according to claim 3, characterized in that, The dehumidification solution-cooling water heat exchanger is connected with the several nozzles.

5. The flue gas dehumidification and waste heat utilization system according to claim 4, characterized in that, The dehumidification solution-cooling water heat exchanger is provided with a cooling water inlet and a cooling water outlet, the cooling water input through the cooling water inlet cools the dehumidification solution input from the dehumidification solution storage tank, and the cooling water with increased temperature is discharged through the cooling water outlet.

6. The flue gas dehumidification and waste heat utilization system according to claim 3, characterized in that, The flue gas dehumidification and waste heat utilization system further comprises a first controller, a second controller, a third controller, a fourth controller, and a fifth controller; A flue gas humidity sensor is arranged between the dry flue gas exhaust outlet and the chimney, and the flue gas humidity sensor is electrically connected with the first controller. The dehumidification solution storage tank is provided with a first solution concentration sensor, and the first solution concentration sensor is electrically connected with the second controller; The heat pipe type dehumidification solution regeneration device is provided with a second solution concentration sensor between the heat pipe type dehumidification solution regeneration device and the dehumidification solution storage tank inlet, and the second solution concentration sensor is electrically connected with the third controller; The absorption tower is provided with a third solution concentration sensor between the absorption tower and the heat pipe type dehumidification solution regeneration device inlet, and the third solution concentration sensor is electrically connected with the fourth controller; The first controller calculates the optimal flue gas emission humidity based on the ambient temperature and humidity, the flue gas humidity sensor collects the dry flue gas humidity of the dry flue gas emission outlet in real time and transmits it to the first controller, the first controller judges whether the current dry flue gas humidity is the optimal flue gas emission humidity, if not, the concentration required by the current dehumidification solution is calculated based on the error, and the second controller, the third controller and the fourth controller are input respectively; The fourth controller receives the dehumidification solution concentration obtained by the third solution concentration sensor, compares the concentration required by the dehumidification solution, and controls the heat pipe type dehumidification solution regeneration device to change the concentration of the dehumidification dilute solution after dehumidification.

7. The flue gas dehumidification and waste heat utilization system according to claim 6, characterized in that, The dehumidification solution storage tank is provided with a dehumidifier storage device and a stirrer, and the dehumidifier storage device is electrically connected with the fifth controller; The third controller receives the dehumidification solution concentration obtained by the second solution concentration sensor, compares the concentration required by the dehumidification solution, and if the dehumidification solution concentration does not meet the concentration requirement, transmits an error signal to the fifth controller, and the fifth controller controls the dehumidifier storage device to add a corresponding amount of dehumidifier to the dehumidification solution storage tank according to the error signal.

8. A flue gas dehumidification and waste heat utilization method, based on the flue gas dehumidification and waste heat utilization system of any one of claims 1-7, characterized in that, The following steps are included: The dehumidification concentrated solution stored in the dehumidification solution storage tank is cooled by the dehumidification solution-cooling water heat exchanger and the cooling water, and then input into the absorption tower, the cooled dehumidification concentrated solution in the absorption tower dehumidifies the desulfurization wet flue gas input from the wet desulfurization tower and is converted into dehumidification dilute solution, and the dehumidification dilute solution is input into the heat pipe type dehumidification solution regeneration device, and the dry flue gas after dehumidification is discharged; The heat pipe type dehumidification solution regeneration device absorbs the boiler flue gas waste heat and inputs the boiler flue gas into the wet desulfurization tower, the heat pipe type dehumidification solution regeneration device heats and evaporates the input dehumidification dilute solution by absorbing the boiler flue gas waste heat to obtain dehumidification concentrated solution, and then the dehumidification concentrated solution is input into the dehumidification solution storage tank for storage.

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