Energy-saving device for automatic adjustment of waste power plant flue gas waste heat recovery

Abstract

The utility model relates to an energy -conserving device of garbage power plant flue gas waste heat recovery automatic regulation uses, it solved the existing garbage incineration power plant garbage incineration efficiency low, discharges the flue gas temperature high, acid flue gas heat can not effectively utilize's technical problem, it is equipped with flue gas heat exchanger, air heating system and air replacement device, the flue gas heat exchanger sets up between the cloth bag dust catcher and the chimney of incinerator, air heating system sets up before incinerator primary fan, the flue gas heat exchanger is equipped with water line and flue line, air heating system is equipped with water line and air line, the water line of flue gas heat exchanger with air heating system's water line and deoxygenated water heating device are connected through circulating water pump, air heating system air line communicates air replacement device and incinerator primary wind passageway. The utility model can be widely applied to garbage incineration power plant garbage incineration occasion.

Description

Technical Field

[0001] This utility model relates to the field of waste treatment, and in particular to an energy-saving device for automatic regulation of waste heat recovery from flue gas in waste-to-energy plants. Background Technology

[0002] After municipal solid waste enters a waste-to-energy plant, it first undergoes repeated stacking by a garbage crane. Under a certain temperature, it ferments for 5-7 days to remove leachate and increase its calorific value before incineration. However, due to the lower temperatures in autumn and winter, the stacking fermentation efficiency is low, resulting in ineffective fermentation and low calorific value. Auxiliary fuel is needed to ensure the normal operation of the waste-to-energy boiler. Furthermore, due to the unique nature of waste incineration, the flue gas is highly acidic and has a high exhaust temperature, making heat utilization inefficient. Forcibly lowering the flue gas temperature causes it to reach the acid dew point, easily leading to corrosion. Additionally, incomplete desulfurization using dry / semi-dry methods during incineration also contributes to chimney corrosion. The latest environmental regulations require incinerator exhaust temperatures to be controlled below 45℃. Therefore, how to rationally utilize the waste heat from the waste-to-energy boiler flue gas and effectively ferment the waste in autumn and winter to reduce acid corrosion has become an urgent problem to be solved. Summary of the Invention

[0003] This invention addresses the technical problems of low waste incineration efficiency, high flue gas temperature, and ineffective utilization of acidic flue gas heat in waste-to-energy plants by providing an energy-saving device for automatically regulating waste heat recovery from waste-to-energy plants to improve the efficiency of waste stacking fermentation.

[0004] This utility model provides an energy-saving device for automatic regulation of waste heat recovery from flue gas in a waste-to-energy plant. It includes a flue gas heat exchanger, an air heating system, and an air replacement device. The flue gas heat exchanger is located between the bag filter and the chimney of the incinerator. The air heating system is located before the primary air fan of the incinerator. The flue gas heat exchanger has water and flue gas pipes, and the air heating system has water and air pipes. The water pipes of the flue gas heat exchanger are connected to the water pipes of the air heating system and the deoxygenated water heating device via a circulating water pump. The air pipes of the air heating system are connected to the air replacement device and the primary air duct of the incinerator.

[0005] Preferably, an induced draft fan is provided between the flue gas heat exchanger and the chimney, and an acid-reducing scrubbing tower for water washing, cooling and acid removal is provided between the induced draft fan and the chimney. The acid-reducing scrubbing tower reduces the flue gas temperature, absorbs solid particles and reduces the acidity of the flue gas through spraying. The acid-reducing scrubbing tower is also equipped with a cooler, which is connected to the cooling tower.

[0006] Preferably, a maintenance bypass flue is also provided in parallel with the flue of the acid desulfurization scrubbing tower, and valves for adjusting the direction of flue gas are respectively provided at both ends of the acid desulfurization scrubbing tower and the maintenance bypass flue.

[0007] Preferably, a condensing heat exchanger is provided between the induced draft fan and the acid-reducing scrubbing tower. The condensing heat exchanger is connected to a device that requires heat through a pipeline, including but not limited to a domestic heating network or the air replacement device, for use in community heating or garbage bin heating.

[0008] Preferably, the condensing heat exchanger is connected in parallel with a condensing heat exchanger bypass flue, and the acid-reducing scrubbing tower and the condensing heat exchanger flue are connected in parallel with a common bypass flue. Valves are provided at both ends of the condensing heat exchanger, and a valve is provided at the top of the acid-reducing scrubbing tower. At the same time, valves are installed on the condensing heat exchanger bypass flue and the common bypass flue. The direction of the flue gas is controlled by opening and closing the valves.

[0009] Preferably, one end of the air heating system is connected to a sixth regulating valve for opening or closing the air entering the air heating system, and the other end is connected to a fourth regulating valve and a fifth regulating valve respectively. The fourth regulating valve is connected to the air replacement device through the air circulation fan. The fifth regulating valve is connected to the air waste heat treatment system for heating the primary air of the boiler. A seventh regulating valve is also provided in parallel with the air heating system.

[0010] Preferably, the air exchange device is equipped with jet rotary nozzles and push-pull motors that perform forced convection heat exchange between the cold air in the waste bin and the surface of the waste, and the push-pull motors control the position adjustment of the jet rotary nozzles.

[0011] The beneficial effects of this utility model are:

[0012] This invention features an air heating system at the boiler's front end. A flue gas heat exchanger is installed between the boiler's induced draft fan outlet and the chimney. The flue gas filtered from waste incineration undergoes gas-water heat exchange through the heat exchanger, generating a heat transfer medium, which is directly connected to the air heating system for circulating heat supply. The air heating system utilizes this heat transfer medium to exchange heat with the air drawn in by the primary air fan, effectively increasing the primary air temperature and reducing heat loss during primary air heating. The primary air fan draws air from the waste bin, creating negative pressure within the bin to prevent the diffusion of waste odors.

[0013] The flue gas heat exchanger also utilizes a switchable pipe network to heat the waste in the waste bin. When the weather changes and the temperature of the waste in the bin is too low, or the waste has high humidity and low calorific value, affecting the boiler's heating, the air heating system uses hot water as a heat transfer medium to heat the air, providing high-temperature hot air to the waste bin. The high-temperature hot air enters the ejector through the air exchange device's duct, forcing convection heat exchange between the cold air in the waste bin and the surface of the waste, increasing the waste temperature, accelerating the drying and fermentation of the waste, increasing the calorific value of the waste, reducing the need to add auxiliary fuel in winter due to the waste's ineffective fermentation, reducing energy loss, and avoiding energy waste.

[0014] This invention also includes an acid-reducing scrubbing tower between the flue gas heat exchanger and the chimney. Since waste incineration requires dry or semi-dry dust removal methods, which cannot completely remove acidic substances from the flue gas, the acid-reducing scrubbing tower sprays alkaline water. Through acid-base neutralization, the acidic substances in the flue gas are removed again, achieving the required pH emission standards, protecting the flue, and preventing corrosion. Simultaneously, the spraying water washing method reduces the flue gas temperature to below 45℃, while ensuring that the 24-hour average particulate matter emission concentration does not exceed 5 mg / m³. 3 The 24-hour average emission concentration of nitrogen oxides shall not exceed 80 mg / m³. 3 The 24-hour average emission concentration of hydrogen chloride is no higher than 8 mg / m³. 3 . Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the structure of the energy-saving device in the incinerator according to Embodiment 1 of this utility model;

[0016] Figure 2 This is a flowchart illustrating the process of this utility model;

[0017] Figure 3 This is a schematic diagram of the main view structure of the air exchange device of this utility model;

[0018] Figure 4 This is a structural schematic diagram of the air exchange device of this utility model from the left side view;

[0019] Figure 5 This is a schematic diagram showing the location of the air replacement device of this utility model in the garbage bin;

[0020] Figure 6a This is a process flow diagram of the energy-saving system in Embodiment 2 of this utility model at the downstream end of the bag filter dust collector in the incinerator;

[0021] Figure 6b This is a schematic diagram of the structure of the energy-saving system at the rear end of the bag filter in the incinerator in Embodiment 2 of this utility model;

[0022] Figure 7aThis is a process flow diagram of the energy-saving system in Embodiment 3 of this utility model at the downstream end of the bag filter in the incinerator;

[0023] Figure 7b This is a schematic diagram of the energy-saving system of Embodiment 3 of this utility model at the rear end of the bag filter of the incinerator;

[0024] Figure 8a This is a process flow diagram of the energy-saving system in Embodiment 4 of this utility model at the downstream end of the bag filter dust collector in the incinerator;

[0025] Figure 8b This is a schematic diagram of the energy-saving system in Embodiment 4 of this utility model at the rear end of the bag filter in the incinerator.

[0026] Explanation of symbols in the attached drawings:

[0027] 1. Air duct; 2. Guardrail; 3. Frame; 4. Push-pull motor; 5. Slide support; 6. Jet rotary nozzle; 7. Arched push-pull rod; 10. Garbage pit; 20. Incinerator; 21. Feed hopper; 22. Chute; 30. Desulfurization tower; 40. Bag filter; 50. Chimney; 600. Acid reduction scrubbing tower; 601. Flue gas heat exchanger; 602. Exhaust fan; 603. First regulating switching valve; 604. Second regulating switching valve; 605. Third regulating switching valve. 606. Valve; 607. Circulating water pump; 608. Air heating system; 609. Fourth regulating switching valve; 610. Fifth regulating switching valve; 611. Air circulation fan; 612. Sixth regulating switching valve; 613. Seventh regulating switching valve; 614. Deoxygenated water; 615. Secondary condenser; 616. Cooler; 620. Cooling tower; 621. Domestic heating network; 722. Garbage bin; 73. Air intake; 74. Waste heat exchanger system; 75. Primary air fan. Detailed Implementation

[0028] The present invention will be further described below with reference to the accompanying drawings and embodiments, so that those skilled in the art to which the present invention pertains can easily implement the present invention.

[0029] Example 1: As Figure 1 The diagram shows the structure of the energy-saving device of this invention in an incinerator-waste heat boiler. This invention is arranged around an existing incinerator-waste heat boiler, which sequentially includes a waste pit 10, an incinerator 20, a desulfurization tower 30, a bag filter 40, and a chimney 50. The waste pit 10 provides heat from waste incineration to the incinerator 20 via a feed hopper 21 and a chute 22. After combustion, the high-temperature flue gas passes through the desulfurization tower 30 and the bag filter 40 before entering the chimney 50. Air from the waste pit 10 enters the air waste heat treatment system 72 through an air intake 71 and is heated to approximately 200 degrees Celsius before passing through a primary air fan 73 and entering the incinerator 20 for combustion.

[0030] This invention includes an induced draft fan 602 and a flue gas heat exchanger 601 installed between the bag filter 40 and the chimney 50. The positions of the induced draft fan 602 and the flue gas heat exchanger 601 can be interchanged as needed. Three regulating valves control the opening and closing of the flue gas heat exchanger 601 and the adjustment of the flue gas volume, achieving waste heat recovery and utilization. The induced draft fan 602 guides the heated gas discharged from the bag filter 40 into the flue gas heat exchanger 601, heating the water within the flue gas heat exchanger 601. The first regulating valve 603 and the second regulating valve 604 are connected in series across the flue gas heat exchanger 601. The third regulating valve 605 is connected in parallel with the first regulating valve 603, the second regulating valve 604, and the flue gas heat exchanger 601. When the flue gas heat exchanger 601 needs to be shut down, the first regulating valve 603 and the second regulating valve 604 are closed, and the third regulating valve 605 is opened. Conversely, when the flue gas heat exchanger 601 needs to be activated, the first regulating valve 603 and the second regulating valve 604 are opened, and the third regulating valve 605 is closed. When the flue gas volume needs to be adjusted, the first regulating valve 603, the second regulating valve 604, and the third regulating valve 605 are all opened. The degree of opening of the third regulating valve 605 is adjusted to control the amount of flue gas to be discharged.

[0031] Water heated by flue gas heat exchanger 601 enters air heating system 607 via circulating water pump 606, providing a heat source for air heating system 607. Air heating system 607 can heat waste bin 10 or primary air entering incinerator 20 according to actual needs, improving overall boiler efficiency and saving energy. The air heating system 607 is connected to the air intake 71, the air circulation fan 610, and the air waste heat exchanger system 72 via multiple regulating valves. One end of the air heating system 607 is connected to the sixth regulating valve 611, which is used to open or close the air entering the air heating system 607. The other end is connected to the fourth regulating valve 608 and the fifth regulating valve 609. The fourth regulating valve 608 is connected to the air duct 1 of the air replacement device through the air circulation fan 610, and is used to provide heat to the garbage bin 10. The fifth regulating valve 609 is connected to the air waste heat exchanger system 72, and is used to heat the primary air of the boiler. The seventh regulating valve 612 is connected in parallel with the air heating system 607 and can be used to shut down the air heating system 607 during maintenance.

[0032] After passing through the flue gas heat exchanger 601, the flue gas temperature drops significantly, easily reaching the acid dew point. To prevent acid corrosion of the chimney and to meet the latest environmental protection requirements that the flue gas temperature be below 45 degrees Celsius, an acid-reducing scrubbing tower 600 is installed between the flue gas heat exchanger 601 and the second regulating switching valve 604. The acid-reducing scrubbing tower 600 is used to wash and cool the flue gas after it has been cooled by the flue gas heat exchanger 601, washing out solid particles and acidic substances such as sulfur dioxide and nitrogen oxides. Through acid-base neutralization reactions, the pollutants in the flue gas are reduced, and the flue gas temperature is lowered to ensure compliance with the latest environmental protection requirements. The flue gas enters the acid-reducing scrubbing tower 600, undergoes multiple spray cooling processes, absorbs solid particles and water from the acid-base neutralization reaction, and is reused after heat dissipation and filtration. It then re-enters the spray nozzles for water washing again. After water washing, the flue gas temperature is below 45 degrees Celsius before being discharged into the chimney 50.

[0033] When the temperature is low in autumn and winter, and the temperature of the garbage bin 10 is low, heat needs to be provided to the garbage bin 10. The flue gas heat exchanger 601 is activated, the first regulating valve 603 and the second regulating valve 604 are opened, and the third regulating valve 605 is closed. The flue gas heat exchanger 601 absorbs the residual heat in the high-temperature flue gas. The heated water enters the air heating system 607 through the circulating water pump 606. The fifth regulating valve 609 and the seventh regulating valve 612 are closed, and the fourth regulating valve 608 and the sixth regulating valve 611 are opened. The air circulation fan 610 draws in air from the air inlet 71, enters the air heating system 607 for heating through the sixth regulating valve 611, and enters the air replacement device of the garbage bin 10 through the fourth regulating valve 608. Hot air is sprayed into the garbage bin using the jet rotating nozzle 6. The hot air agitates the cold air in the garbage bin, forcing convection heat exchange. The hot air mixes with the cold air in the garbage bin, increasing the temperature of the garbage bin and removing moisture from the surface of the garbage, thus accelerating the drying of the garbage.

[0034] During spring and summer, when temperatures rise and heating of the waste storage area is no longer required, the air circulation fan 610, the fourth regulating valve 608, and the seventh regulating valve 612 are shut down. The sixth regulating valve 611 and the fifth regulating valve 609 are opened. The primary air fan 73 draws air from the intake port 71. After being heated to approximately 80 degrees Celsius by the sixth regulating valve 611 and the air heating system 607, the air enters the waste heat recovery system 72 through the fifth regulating valve 609 for further heating. Once the air reaches approximately 200 degrees Celsius, it enters the primary air fan 73 and is supplied to the boiler for combustion. This recovers waste heat from the flue gas, effectively reducing the energy requirements of the waste heat recovery system 72.

[0035] This invention recycles and utilizes waste heat from the chimney 50 according to seasonal or actual needs, providing it to the waste bin 10 for fermentation or to assist the air waste heat exchanger system 72 in heating the air, thus reducing the heat demand of the air waste heat exchanger system 72. PLC control is used to adjust various regulating valves and circulating water pumps, rapidly adjusting the direction of air, water flow, and flue gas flow to achieve automated control.

[0036] The flue gas heat exchanger 601, which provides heat, can also provide heat to other applications requiring heating. For example, the hot water output from the flue gas heat exchanger 601 can be used to heat the heat exchange unit, thereby raising the temperature of the deoxygenated water. Similarly, the air circulation fan 610 can also collect heat from other structures as needed for air heating.

[0037] like Figure 2 The diagram shown is a flowchart of the energy-saving method of this utility model. The specific steps of this utility model include:

[0038] Step 1: Install a flue gas heat exchanger in the middle section from the exhaust fan outlet to the chimney to perform gas-water heat exchange, and generate heat transfer medium water through the flue gas heat exchanger.

[0039] Step 2: The heat transfer medium water is directly connected to the air heating system to circulate and deliver the heat source. The air heating system uses the heat transfer medium water to exchange heat with the drawn-in air.

[0040] Step 3: The exchanged hot air is supplied to the primary air fan as a heat source to increase the temperature of the primary air, depending on actual needs. Alternatively, if the temperature of the garbage in the garbage bin is too low, causing icing, or if the humidity is too high and the calorific value is too low, affecting the boiler's heating, the exchanged hot air can be adjusted and transferred to the air circulation fan to provide high-temperature hot air replacement to the garbage bin, thereby increasing the temperature of the garbage and space inside the bin.

[0041] Step 4: Hot air is delivered through the air duct to the jet rotating nozzles installed in the waste bin, which replace the cold air on the surface of the waste and inside the bin. The replaced air is then supplied to various fans as fresh air.

[0042] The specific method for replacing cold air with hot air injected by the rotating jet nozzles inside the waste bin is as follows:

[0043] Step 1): Adjust the direction of the jet rotating nozzle of the air replacement device according to the position of the garbage in the garbage bin; start the push-pull motor, which drives the arched push-pull rod to adjust the spray direction of each group of jet rotating nozzles;

[0044] Step 2) Start the jet rotary nozzle and introduce the waste heat from the boiler flue into the jet rotary nozzle through the air duct. After the jet rotary nozzle is aimed at the garbage, it sprays hot air into the garbage bin. The hot air agitates the cold air in the garbage bin, forcing convection heat exchange. The hot air mixes with the cold air in the garbage bin, increasing the temperature of the garbage bin and removing moisture from the surface of the garbage, thus accelerating the drying of the garbage.

[0045] Step 3): After the garbage crane moves the garbage to a different position inside the bin, the position of the accumulated garbage changes. Adjust the position of the jet rotating nozzle and aim the jet rotating nozzle at the garbage again. Repeat steps 1) to 3).

[0046] like Figure 3-5 This is a schematic diagram of the air replacement device for a waste storage bin according to this utility model. Multiple sets of jet replacement devices are evenly distributed on the air duct 1, which connects to the hot air from the waste heat exchanger in the boiler flue. Each set of jet replacement devices has a frame 3 and a rotating jet nozzle 6. The frame 3 is fixed to the air duct 1, and the rotating jet nozzle 6 is also fixed to the air duct 1, with its interior connected to the air duct 1. A push-pull motor 4 is fixed to the frame 3, and the push-pull motor 4 is hinged to an arched push-pull rod 7. The arched push-pull rod 7 is connected to the spherical rotating jet nozzle 6. When the push-pull motor 4 is running, it drives the rotating jet nozzle 6 to change direction. The air duct 1 also has a slide rail bracket 5 to guide the arched push-pull rod 7. One end of the slide rail bracket 5 is fixed to the air duct 1, and the other end has a ring. The arched push-pull rod 7 is fitted inside the ring to guide the sliding direction of the arched push-pull rod 7.

[0047] The ventilation duct 1 can be installed inside or outside the waste bin as needed. If it is installed outside the waste bin, it is connected to the jet rotary nozzle 6 through a branch pipe on the ventilation duct 1. The direction of the jet rotary nozzle 6 is directly controlled by a motor to force heat exchange inside the waste bin and heat up the waste for fermentation. The ventilation duct 1 is also equipped with a protective railing 2 for maintenance at the top.

[0048] Example 2: Figure 6a Figures 4a and 5b show the process flow diagram and structural schematic diagram of the energy-saving system at the downstream end of the bag filter in the incinerator in this embodiment. This embodiment is generally used for temporary operation during summer operation or maintenance. A flue gas heat exchanger 601 is installed between the bag filter 40 and the induced draft fan 602. The heat exchanged through the flue gas heat exchanger 601 is used to heat the deoxygenated water 613 and the primary air of the waste incineration boiler, increasing the temperature of the deoxygenated water and primary air, and improving the combustion efficiency of the waste incinerator. After passing through the bag filter 40, the flue gas in the waste incinerator enters the flue gas heat exchanger 601 for heat exchange and cooling. After cooling, the flue gas is directly discharged into the chimney 50 by the induced draft fan 602. At this time, the flue gas heat exchanger 601 (the primary heat exchanger) generally operates at a temperature higher than the flue gas dew point temperature to avoid corrosion of the chimney 50.

[0049] Example 3: As Figure 7aFigures b and c show the process flow diagram and structural schematic diagram of the energy-saving system at the downstream end of the bag filter in the incinerator in this embodiment. This embodiment is used for the waste-to-energy plant flue gas cooling and emission 45°C waste heat recovery process. This embodiment adds an acid-reducing scrubbing tower 600 and a cooler 615 to the embodiment 2. The acid-reducing scrubbing tower 600 is located downstream of the induced draft fan 602, and the cooler 615 is located at the top of the acid-reducing scrubbing tower 600. The acid-reducing scrubbing tower 600 uses alkaline liquid to wash and cool the flue gas after it has been cooled by the flue gas heat exchanger 601, removing solid particles and acidic substances such as sulfur dioxide and nitrogen oxides from the flue gas. Through acid-base neutralization reaction, the pollutants in the flue gas are reduced, and the flue gas temperature is lowered.

[0050] After being cooled by multiple spraying processes, the flue gas enters cooler 615 for further cooling. After heat exchange in cooler 615, the hot water enters cooling tower 616 for cooling and is then recycled. Once the flue gas temperature is reduced to below 45°C, which meets the latest environmental protection requirements, it is discharged into chimney 50. Cooling tower 616 can be an independent cooling tower or can utilize an existing process cooling tower within the waste-to-energy plant.

[0051] The exhaust fan 602 has two branch flues at its rear end: one is a bypass flue directly connected to the chimney, and the other is a flue connected to the acid-reducing scrubbing tower 600. These two branch flues are controlled separately by valves. When normal flue gas requires cooling and acid reduction, the valve directly connected to the chimney is closed, and the flue gas enters the acid-reducing scrubbing tower 600 for treatment. When maintenance is required on the acid-reducing scrubbing tower 600 and / or the cooler 615, the front valve connecting to the acid-reducing scrubbing tower 600 and the top valve connecting the acid-reducing scrubbing tower 600 to the chimney are closed, and the bypass flue valve directly connected to the chimney is opened to discharge the flue gas. The valves can be controlled manually or automatically to allow flue gas to flow through the bypass channels.

[0052] Example 4: Figure 8a Figures b and c show the process flow diagram and structural schematic diagram of the energy-saving system at the downstream end of the bag filter of the incinerator in this embodiment. This embodiment is designed for winter operation mode and includes a waste heat recovery process for cooling the flue gas emitted by the waste-to-energy plant to 45°C. It utilizes the waste heat from the waste incinerator to connect with the domestic heating network. After heat exchange, the waste heat from the waste incinerator is used to make hot water enter the domestic heating network to provide winter heating for residents. This embodiment adds a secondary condenser 614 to the existing embodiment 3. The secondary condenser 614 is installed between the induced draft fan 602 and the acid-reducing scrubbing tower 600. The secondary condenser 614 continues to exchange heat with the flue gas after it has been heat-exchanged by the flue gas heat exchanger 601, further extracting the latent heat in the flue gas and recovering the heat from the condensed water vapor. The recovered heat provides heat to the domestic heating network 620 and the garbage bin 621. In the secondary condenser 614 (condensing heat exchanger), the flue gas is further cooled and water vapor is condensed for use in garbage bin heating, community heating, and factory heating, significantly improving the overall thermal energy utilization efficiency of the system.

[0053] In this embodiment, a secondary condenser bypass flue is connected in parallel to the secondary condenser 614, and a common bypass flue is connected in parallel to the acid desulfurization scrubbing tower 600 and the flue of the secondary condenser 614. Valves are provided at both ends of the secondary condenser 614, and a valve is provided at the top of the acid desulfurization scrubbing tower 600. Valves are also installed on the secondary condenser bypass flue and the common bypass flue. The direction of the flue gas is controlled by opening and closing the valves.

[0054] The opening and closing of the acid-reducing scrubbing tower 600 and the secondary condenser 614 are selected according to emission index requirements or actual operational needs. The valve selection allows for the following modes: the acid-reducing scrubbing tower 600 and the secondary condenser 614 to operate without any valves, the acid-reducing scrubbing tower 600 to operate alone, or the acid-reducing scrubbing tower 600 and the secondary condenser 614 to operate simultaneously. For example, when there is no demand for heating, there is no need to extract latent heat from the flue gas. The valves before and after the secondary condenser 614 can be closed, and the bypass flue of the secondary condenser can be opened, allowing the flue gas to directly enter the acid-reducing scrubbing tower 600 for cooling and acid removal. When maintenance or replacement of the acid-reducing scrubbing tower 600 and the secondary condenser 614 is required, the valves before and after the acid-reducing scrubbing tower 600 and the secondary condenser 614 can be closed, and the common bypass flue can be opened to discharge the flue gas, preventing the entire waste incinerator from shutting down.

[0055] The part of the secondary condenser 614 that comes into contact with the flue gas is made of a material resistant to acid and alkali corrosion. The bottom of the secondary condenser 614 is equipped with an alkaline sedimentation tank to neutralize the acidic liquid formed by the condensation of the secondary condenser 614.

[0056] This invention firstly recovers and utilizes the waste heat from the flue gas of a waste-to-energy plant, generating economic benefits. Secondly, it achieves ultra-low flue gas temperature emissions, reduces acid discharge, generating social benefits, and avoids equipment corrosion. The use of a step-by-step acid removal operation reduces operating costs during waste incineration. This invention constructs a low-temperature emission and deep treatment system, aiming to achieve stable flue gas temperature control below 45℃ while ensuring stable system operation, and simultaneously achieving the dual goals of deep cascade utilization of heat and synergistic reduction of pollutants. In summer, the system primarily operates the primary heat exchanger (flue gas heat exchanger), extracting sensible heat from the high-temperature flue gas for deoxygenated water heating and primary air preheating, meeting the basic thermal load of the boiler system. Due to lower social heating demand during this period, the secondary condenser and acid removal scrubbing tower are usually shut down. The system uses a cooling tower to systematically dissipate excess heat to maintain overall thermal balance and system safety. If specific exhaust emission control requirements exist in summer, the system can selectively activate the tail scrubbing unit to further enhance pollutant removal capabilities.

[0057] In winter operation mode, flue gas passes sequentially through a primary heat exchanger (flue gas heat exchanger) and a secondary condenser heat exchanger (condenser), achieving cascaded recovery of sensible and latent heat. The primary heat exchanger (flue gas heat exchanger) continues to heat the deoxygenated water and primary air; the condenser heat exchanger further reduces the flue gas temperature below the dew point, deeply recovering latent heat, and the resulting medium-low temperature hot water is used for external load scenarios such as waste storage heating and municipal centralized heating. Simultaneously, all exhaust gas is treated by a tail-end scrubbing tower, achieving liquid-phase synergistic removal of pollutants in a low-temperature, high-humidity environment, ensuring compliance with environmental emission standards.

[0058] The structure of this utility model is optimized by moving the induced draft fan between the primary heat exchanger (flue gas heat exchanger) and the condenser heat exchanger, which effectively reduces the temperature and volumetric flow rate of the flue gas entering the induced draft fan, thereby significantly reducing the power requirement and operating energy consumption of the induced draft fan and improving the overall energy-saving level of the system.

[0059] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the scope of the claims of the present invention should be within the protection scope of the present invention.

Claims

1. A kind of energy-saving device for automatic adjustment of waste power plant flue gas waste heat recovery, it is characterized in that, it The system includes a flue gas heat exchanger, an air heating system, and an air replacement device. The flue gas heat exchanger is located between the bag filter and the chimney of the incinerator, and the air heating system is located before the primary air fan of the incinerator. The flue gas heat exchanger has water pipes and flue gas pipes, and the air heating system has water pipes and air pipes. The water pipes of the flue gas heat exchanger are connected to the water pipes of the air heating system and the deoxygenated water heating device via a circulating water pump. The air pipes of the air heating system are connected to the air replacement device and the primary air duct of the incinerator.

2. The energy-saving device for automatic regulation of waste power plant flue gas waste heat recovery according to claim 1, characterized in that, An induced draft fan is provided between the flue gas heat exchanger and the chimney. An acid-reducing scrubbing tower for water washing, cooling and acid removal is provided between the induced draft fan and the chimney. The acid-reducing scrubbing tower reduces the flue gas temperature, absorbs solid particles and reduces the acidity of the flue gas through spraying. A cooler is also provided on the acid-reducing scrubbing tower and is connected to the cooling tower.

3. The energy-saving device for automatic regulation of waste heat recovery from flue gas in waste-to-energy plants according to claim 2, characterized in that, A maintenance bypass flue is also provided in parallel with the flue of the acid degrading scrubbing tower. Valves for adjusting the direction of flue gas are provided at both ends of the acid degrading scrubbing tower and the maintenance bypass flue.

4. The energy-saving device for automatic regulation of waste power plant flue gas waste heat recovery according to claim 2, characterized in that, A condensing heat exchanger is provided between the induced draft fan and the acid-reducing scrubbing tower. The condensing heat exchanger is connected to devices that require heat through pipelines, including but not limited to domestic heating networks or the air replacement device, for use in community heating or garbage bin heating.

5. The energy saving device for automatic regulation of waste power plant flue gas waste heat recovery according to claim 4, characterized in that, The condensing heat exchanger is connected in parallel with a condensing heat exchanger bypass flue. The acid-reducing scrubbing tower and the condensing heat exchanger flue are connected in parallel with a common bypass flue. Valves are provided at both ends of the condensing heat exchanger and at the top of the acid-reducing scrubbing tower. Valves are also installed on the condensing heat exchanger bypass flue and the common bypass flue. The direction of the flue gas is controlled by opening and closing the valves.

6. The energy saving device for automatic regulation of waste power plant flue gas waste heat recovery according to claim 1, characterized in that, One end of the air heating system is connected to a sixth regulating valve, which is used to open or close the air entering the air heating system. The other end is connected to a fourth regulating valve and a fifth regulating valve. The fourth regulating valve is connected to the air replacement device through the air circulation fan. The fifth regulating valve is connected to the air waste heat treatment system and is used to heat the primary air of the boiler. A seventh regulating valve is also provided in parallel with the air heating system.

7. The energy saving device for automatic regulation of waste power plant flue gas waste heat recovery according to claim 1, characterized in that, The air exchange device is equipped with jet rotary nozzles and push-pull motors that perform forced convection heat exchange between the cold air in the waste bin and the surface of the waste. The push-pull motors control the position adjustment of the jet rotary nozzles.

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