A sludge drying system based on direct heat taking of waste power plant flue gas waste heat

Abstract

The utility model discloses a kind of sludge drying systems based on waste power plant flue gas waste heat direct heat extraction formula, belong to waste heat utilization technical field, and the spray liquid generated by spray heat exchanger provides heat source for vacuum sludge evaporation equipment by conveying channel.This scheme directly recycles waste power plant flue gas waste heat by spray heat exchanger, and the originally wasted high-temperature flue gas heat is converted into the heat source of sludge drying, and the dependence on traditional electricity, steam and other energy is greatly reduced.Spray liquid circulation system realizes closed cycle utilization of heat, reduces heat loss, and improves energy utilization rate.Taking jacketed sludge drying box as an example, flash evaporation process under negative pressure environment can complete sludge drying at lower temperature, further reduces energy consumption compared with traditional normal pressure drying.In addition, the setting of heat supplement device can cope with flue gas waste heat fluctuation, ensure that system can stably operate under different working conditions, reduce downtime or efficiency decline caused by insufficient heat source quality and quantity, reduce comprehensive operation cost.

Description

Technical Field

[0001] This utility model belongs to the field of waste heat utilization technology, and in particular to a sludge drying system based on direct heat extraction of waste heat from flue gas in a waste-to-energy plant. Background Technology

[0002] With the acceleration of urbanization, the amount of sludge produced by wastewater treatment plants is increasing year by year, and sludge drying is a key link in volume reduction and resource utilization. However, traditional drying technologies rely on fossil fuels or electricity to provide heat sources, resulting in high energy consumption and large carbon emissions. At the same time, the flue gas from waste incineration power plants contains a large amount of waste heat (temperature typically 120-200℃), but existing waste heat recovery technologies are mostly used for power generation or heating, and are not fully adapted to the sludge drying scenario. Utility Model Content

[0003] Purpose of the utility model: To provide a sludge drying system based on direct heat extraction from waste gas from a waste-to-energy plant, so as to solve the above-mentioned problems existing in the prior art.

[0004] Technical solution: A sludge drying system based on direct heat extraction from waste gas from a waste-to-energy plant, comprising: a spray heat exchanger, wherein the spray liquid of the spray heat exchanger directly extracts heat from the flue gas and then provides a heat source for a vacuum sludge evaporation device through a conveying channel.

[0005] Furthermore, the spray heat exchanger is provided with a flue gas inlet and a flue gas outlet.

[0006] Furthermore, the flue gas inlet is the flue gas inlet of the waste-to-energy plant, and the flue gas outlet is the flue gas outlet of the waste-to-energy plant.

[0007] Furthermore, the vacuum sludge evaporation equipment delivers the sprayed liquid after releasing heat to the spray heat exchanger through the return liquid channel.

[0008] Furthermore, a circulation pump is provided on the return channel or the delivery channel.

[0009] Furthermore, the sludge vapor generated by the vacuum sludge evaporation equipment is connected to the condenser through the vapor channel.

[0010] Furthermore, the vacuum sludge evaporation equipment is a jacketed sludge drying box.

[0011] Furthermore, the vacuum sludge evaporation equipment is a vacuum disc sludge dryer.

[0012] Furthermore, it also includes a vacuum pump, which is connected to the condenser via a pipeline to establish a vacuum environment inside the vacuum sludge evaporation equipment.

[0013] Furthermore, the condenser is provided with a cooling water inlet and a cooling water outlet.

[0014] Furthermore, the condenser is provided with a sludge condensate outlet.

[0015] Furthermore, a dust removal device is installed on the exhaust steam passage.

[0016] Furthermore, a heat replenishment device is provided on the conveying channel.

[0017] Beneficial effects:

[0018] This solution directly recovers waste heat from waste-to-energy plant flue gas via a spray heat exchanger, converting previously wasted high-temperature flue gas heat into a heat source for sludge drying, significantly reducing reliance on traditional energy sources such as electricity and steam. The spray liquid circulation system achieves closed-loop heat recycling, reducing heat loss and improving energy efficiency. Taking the jacketed sludge drying box as an example, the flash evaporation process under negative pressure can complete sludge drying at lower temperatures, further reducing energy consumption compared to traditional atmospheric pressure drying. Furthermore, the addition of a supplementary heating device can cope with fluctuations in flue gas waste heat, ensuring stable system operation under different conditions, reducing downtime or efficiency decline due to insufficient heat source quality and quantity, and lowering overall operating costs. Attached Figure Description

[0019] Figure 1 This is a system diagram of this utility model.

[0020] The attached diagram is labeled as follows: spray heat exchanger 100, flue gas inlet 110, flue gas outlet 120, conveying channel 200, vacuum sludge evaporation equipment 300, return liquid channel 400, circulating pump 500, exhaust steam channel 600, condenser 700, cooling water inlet 710, cooling water outlet 720, sludge condensate outlet 730, vacuum pump 800, and reheating device 900. Detailed Implementation

[0021] In the following description, numerous specific details are set forth in order to provide a more thorough understanding of the present invention. However, it will be apparent to those skilled in the art that the present invention can be practiced without one or more of these details. In other instances, certain technical features well-known in the art have not been described in order to avoid confusion with the present invention.

[0022] Combined with appendix Figure 1Description: A sludge drying system based on direct heat extraction from waste-to-energy flue gas includes: a spray heat exchanger 100, wherein the spray liquid of the spray heat exchanger 100 directly extracts heat from the flue gas and then provides a heat source for a vacuum sludge evaporation device 300 via a conveying channel 200. The spray heat exchanger 100 is provided with a flue gas inlet 110 and a flue gas outlet 120. The flue gas inlet 110 is the flue gas inlet of the waste-to-energy plant, and the flue gas outlet 120 is the flue gas outlet of the waste-to-energy plant. The vacuum sludge evaporation device 300 conveys the spray liquid after releasing heat to the spray heat exchanger 100 via a return liquid channel 400. A circulation pump 500 is provided on the return liquid channel 400 or the conveying channel 200. The sludge exhaust steam generated by the vacuum sludge evaporation device 300 is connected to a condenser 700 via an exhaust steam channel 600. The vacuum sludge evaporation device 300 is a jacketed sludge drying box. The vacuum sludge evaporation equipment 300 is a vacuum disc sludge dryer. It also includes a vacuum pump 800, which is connected to a condenser 700 via pipeline to establish a vacuum environment inside the vacuum sludge evaporation equipment 300. The condenser 700 is equipped with a cooling water inlet 710 and a cooling water outlet 720. The condenser 700 is also equipped with a sludge condensate outlet 730. A dust removal device 1000 is installed on the exhaust steam passage 600. A heat exchange device 900 is installed on the conveying passage 200.

[0023] The spray heat exchanger 100, as the core component for flue gas waste heat recovery, has a flue gas inlet 110 and a flue gas outlet 120 that are directly connected to the flue gas channel of the waste-to-energy plant. The spray liquid exchanges heat with the flue gas within the heat exchanger, increasing the contact area and improving heat exchange efficiency through spraying. The spray structure reduces the risk of scaling, facilitates maintenance, and can quickly absorb the sensible heat of the flue gas, transferring the heat to the spray liquid to provide a stable heat source for subsequent sludge drying. The flue gas after heat exchange is discharged from the flue gas outlet 120, reducing thermal pollution while achieving waste heat recovery. When the vacuum sludge evaporation equipment 300 is a jacketed sludge drying box, its structure mainly includes an evaporation chamber and a heat source chamber surrounding the evaporation chamber. The heat source chamber is connected to the spray heat exchanger 100 through a return liquid channel 400 and a conveying channel 200, and is powered by a circulating pump 500. Sludge is placed in the evaporation chamber and flash-evaporates under negative pressure. The heat source chamber continuously provides heat to complete the sludge drying.

[0024] Conveying channel 200: Responsible for conveying the high-temperature spray liquid after heat absorption in the spray heat exchanger 100 to the vacuum sludge evaporation equipment 300. A circulating pump 500 installed on the channel provides power to ensure continuous circulation of the spray liquid. When the system's heat source quantity or quality is insufficient, the supplementary heating device 900 can assist the spray liquid in the conveying channel, ensuring the stability of the drying process, especially suitable for scenarios with fluctuating flue gas waste heat, thus improving system adaptability.

[0025] Vacuum sludge evaporation equipment 300: As the core unit of sludge drying, it can be a jacketed sludge drying box or a vacuum disc sludge dryer. Taking the jacketed type as an example, it includes an evaporation chamber and a heat source chamber. The heat source chamber is connected to the spray heat exchanger 100 through the conveying channel 200 and the return liquid channel 400, forming a closed loop. The sludge in the evaporation chamber undergoes flash evaporation under the negative pressure environment created by the vacuum pump 800. The negative pressure condition can lower the boiling point of water, avoid the damage of high temperature to the sludge components, and at the same time improve the evaporation rate. The heat source chamber continuously supplies high-temperature spray liquid to provide heat for the flash evaporation process. The jacket structure ensures uniform heat transfer and consistent sludge drying effect. The vacuum disc type increases the heating area of ​​the sludge by rotating the disc, improving drying efficiency and is suitable for large-scale processing scenarios.

[0026] Return liquid channel 400: The low-temperature spray liquid that has released heat in the vacuum sludge evaporation equipment 300 is returned to the spray heat exchanger 100 to complete the heat recycling. The channel and the conveying channel 200 form a closed-loop power system through the circulation pump 500, reducing energy loss and improving system energy efficiency.

[0027] Circulation pump 500: Installed in return liquid channel 400 or conveying channel 200, it provides power for the circulation of spray liquid, ensures stable flow of heat medium between heat exchanger and drying equipment, avoids heat supply interruption due to insufficient natural circulation power, and ensures the continuity of drying process.

[0028] Exhaust steam channel 600: Connects the vacuum sludge evaporation equipment 300 and the condenser 700, and is used to transport the exhaust steam generated during the sludge drying process. The dust removal device 1000 installed on the channel can filter out small particles and impurities in the exhaust steam, prevent condenser blockage, improve condensation efficiency, and reduce pollutant emissions.

[0029] Condenser 700: Cooling water is introduced through cooling water inlet 710 and cooling water outlet 720 to condense the exhaust steam. Water vapor in the exhaust steam liquefies upon cooling, forming sludge condensate, which is discharged through sludge condensate outlet 730 for further recycling or treatment. The condensation process reduces the exhaust steam emission temperature, decreasing air pollution, while simultaneously recovering latent heat from the exhaust steam, improving the overall thermal efficiency of the system.

[0030] Vacuum pump 800: Connected to condenser 700 via pipeline, it establishes a vacuum environment inside vacuum sludge evaporation equipment 300. This negative pressure environment not only lowers the evaporation temperature of the sludge moisture but also accelerates the evaporation rate, shortens drying time, and reduces the emission of volatile organic compounds (VOCs), thus improving the working environment.

[0031] Heating device 900: Installed in the conveying channel 200, when the residual heat or quality of the flue gas in the waste-to-energy plant is insufficient, it supplements the heat of the spray liquid through electric heating or other auxiliary heat sources to ensure the heating stability of the vacuum sludge evaporation equipment 300 and avoid the decrease in drying efficiency or incomplete sludge drying due to heat source fluctuations. The heating device 900 can be a heating device or a heating pipeline.

[0032] Work process:

[0033] 1. Flue gas waste heat collection stage

[0034] High-temperature flue gas from the waste-to-energy plant enters the spray heat exchanger 100 through the flue gas inlet 110. The spray liquid is atomized or forms droplets through the spraying device, directly contacting the flue gas. During this process, the flue gas transfers heat to the spray liquid, and after its own temperature decreases, it is discharged from the flue gas outlet 120. The direct contact design of the spray heat exchanger increases the heat exchange area and improves the heat exchange efficiency. At the same time, the flow of the spray liquid can wash away dust in the flue gas, reducing ash accumulation on the equipment.

[0035] 2. Heat transfer and drying stage

[0036] After absorbing heat, the high-temperature spray liquid is transported through the conveying channel 200 and, under the power of the circulating pump 500, to the vacuum sludge evaporation equipment 300, such as a jacketed sludge drying box or a vacuum disc sludge dryer. Taking the jacketed type as an example, the spray liquid enters the heat source chamber of the equipment and transfers heat to the sludge in the evaporation chamber through the jacket structure. At the same time, the vacuum pump 800 evacuates the inside of the evaporation chamber, creating a negative pressure environment, lowering the boiling point of the water in the sludge, and causing it to flash evaporate at a lower temperature, thus achieving drying. During the drying process, the spray liquid releases heat and its temperature decreases, flowing back to the spray heat exchanger 100 through the return liquid channel 400, completing the heat cycle. If the waste heat from the flue gas is insufficient, the supplementary heating device 900 can provide auxiliary heating to the spray liquid in the conveying channel to ensure stable heating.

[0037] 3. Waste steam treatment and condensation stage

[0038] The exhaust steam generated during sludge drying, containing water vapor and a small amount of impurities, enters the condenser 700 through the exhaust steam channel 600. The dust removal device 1000 on the channel first filters the exhaust steam, removing dust and particulate impurities. Cooling water is introduced into the condenser through the cooling water inlet 710 to condense the exhaust steam. The water vapor liquefies to form sludge condensate, which is discharged from the sludge condensate outlet 730 and recycled. The cooled exhaust steam is then treated before being discharged. The cooling water absorbs heat and is discharged from the cooling water outlet 720, which can be further recycled or reused after heat dissipation.

[0039] 4. System Cycle and Control

[0040] The entire system maintains a closed-loop circulation of the spray liquid through the circulation pump 500, maintains a negative pressure environment for the vacuum sludge evaporation equipment through the vacuum pump 800, and monitors parameters such as flue gas temperature, spray liquid flow rate, and vacuum degree in real time through sensors and control systems. It dynamically adjusts the operating status of the circulation pump, vacuum pump, and heating device to ensure that the system can operate efficiently and stably under different working conditions.

[0041] The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the specific details of the above embodiments. Within the scope of the technical concept of the present invention, various equivalent transformations can be made to the technical solutions of the present invention, and all such equivalent transformations fall within the protection scope of the present invention.

Claims

1. A sludge drying system based on direct heat extraction from waste-to-energy flue gas, characterized in that, include: The spray heat exchanger (100) directly heats the spray liquid and flue gas and then provides a heat source to the vacuum sludge evaporation equipment (300) through the conveying channel (200).

2. The sludge drying system based on direct heat extraction from waste-to-energy flue gas as described in claim 1, characterized in that, The spray heat exchanger (100) is provided with a flue gas inlet (110) and a flue gas outlet (120).

3. The sludge drying system based on direct heat extraction from waste-to-energy flue gas as described in claim 2, characterized in that, The flue gas inlet (110) is the flue gas inlet of the waste-to-energy plant, and the flue gas outlet (120) is the flue gas outlet of the waste-to-energy plant.

4. The sludge drying system based on direct heat extraction from waste-to-energy flue gas as described in claim 1, characterized in that, The vacuum sludge evaporation equipment (300) delivers the spray liquid after releasing heat to the spray heat exchanger (100) through the return liquid channel (400).

5. The sludge drying system based on direct heat extraction from waste-to-energy flue gas as described in claim 4, characterized in that, A circulation pump (500) is provided on the return channel (400) or the delivery channel (200).

6. The sludge drying system based on direct heat extraction from waste-to-energy flue gas as described in claim 1, characterized in that, The sludge vapor generated by the vacuum sludge evaporation equipment (300) is connected to the condenser (700) through the vapor channel (600).

7. The sludge drying system based on direct heat extraction from waste-to-energy flue gas as described in claim 1 or 6, characterized in that, The vacuum sludge evaporation equipment (300) is a jacketed sludge drying box.

8. The sludge drying system based on direct heat extraction from waste-to-energy flue gas as described in claim 1 or 6, characterized in that, The vacuum sludge evaporation equipment (300) is a vacuum disc sludge dryer.

9. The sludge drying system based on direct heat extraction from waste-to-energy flue gas as described in claim 6, characterized in that, It also includes a vacuum pump (800), which is connected to the condenser (700) via a pipeline and is used to establish a vacuum environment inside the vacuum sludge evaporation equipment (300).

10. The sludge drying system based on direct heat extraction from waste-to-energy flue gas as described in claim 6, characterized in that, The condenser (700) is provided with a cooling water inlet (710) and a cooling water outlet (720).

11. The sludge drying system based on direct heat extraction from waste-to-energy flue gas as described in claim 6, characterized in that, The condenser (700) is provided with a sludge condensate outlet (730).

12. The sludge drying system based on direct heat extraction from waste-to-energy flue gas as described in claim 6, characterized in that, A dust removal device (1000) is installed on the exhaust steam passage (600).

13. The sludge drying system based on direct heat extraction from waste-to-energy flue gas as described in claim 1, characterized in that, A heating device (900) is provided on the conveying channel (200).

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