Municipal sludge blending combustion wastewater cooling system

Abstract

The utility model relates to a municipal sludge blending combustion wastewater cooling system which can receive high-temperature and high-pressure evaporation tail gas, preliminarily condense the high-temperature and high-pressure evaporation tail gas into wastewater with the first temperature, and then gradually cool the wastewater with the first temperature through a wastewater cooling assembly. And inputting the wastewater into the biochemical pool until the wastewater reaches a set temperature which can be accepted by the biochemical pool. Therefore, the waste water is gradually cooled by arranging a plurality of waste water cooling devices, so that the heat exchange efficiency of the cooling system is improved; and the wastewater cooling device realizes efficient cooling and anti-blocking functions through double design of circulating water shell pass heat exchange and tube pass backwashing, and each valve body controls the flow direction of a medium through opening and closing combination, so that the whole system is ensured to be flexibly switched among normal cooling, backwashing and pollution discharge modes, and the service life of the system is prolonged. Sediments in the tube pass of the waste water cooling device can be removed regularly, so that the efficient heat exchange efficiency of the waste water cooling device is maintained.

Description

Technical Field

[0001] This application relates to the technical field of urban sludge co-firing and drying systems, and in particular to a cooling system for urban sludge co-firing wastewater. Background Technology

[0002] The power plant's coal-fired power generation project, coupled with sludge co-firing, utilizes a sludge disc drying system to dry municipal sludge. Designed for a capacity of 200 t / d, it dries wet sludge with a moisture content of 80% to 35%. During the sludge drying process, the steam and non-condensable gases evaporated enter a tail gas condenser for cooling. A large amount of water vapor condenses here, forming wastewater with a temperature as high as 60°C. To ensure the normal operation of the subsequent wastewater treatment system, this portion of wastewater passes through a wastewater cooling system to reduce its temperature to approximately 30°C.

[0003] However, after the system has been running for a period of time, the temperature of the wastewater after the wastewater cooling system can reach as high as 58°C, which seriously affects the cultivation and living environment of bacteria in the biological tank of the downstream sewage treatment system. It is necessary to frequently replenish water to reduce the temperature of the biological tank and replenish bacteria, resulting in a large waste of resources and a significant increase in operating costs.

[0004] Therefore, it is necessary to design a cooling system for urban sludge co-firing wastewater to improve cooling efficiency and ensure stable system operation. Utility Model Content

[0005] Therefore, it is necessary to provide a cooling system for urban sludge co-firing wastewater to address the current problem of low heat exchange efficiency.

[0006] The first aspect of this application provides a cooling system for wastewater from the co-firing of municipal sludge, comprising:

[0007] A condensation device, the condensation device being adapted to receive evaporation tail gas and condense the evaporation tail gas to a first temperature for wastewater;

[0008] A wastewater cooling assembly includes multiple wastewater cooling devices connected in series, and each wastewater cooling device is adapted to gradually cool wastewater at a first temperature to a set temperature.

[0009] A biological treatment tank, which is adapted to receive wastewater that has reached a set temperature output from the wastewater cooling assembly.

[0010] In one embodiment, the plurality of wastewater cooling devices include a first wastewater cooling device and a second wastewater cooling device connected in series. A wastewater pump is provided between the first wastewater cooling device and the second wastewater cooling device. The inlet of the first wastewater cooling device is connected to the outlet of the condensation device. The outlet of the first wastewater cooling device is connected to the inlet of the wastewater pump. The outlet of the wastewater pump is connected to the inlet of the second wastewater cooling device. The wastewater pump is adapted to pump the wastewater output by the first wastewater cooling device into the second wastewater cooling device.

[0011] In one embodiment, the first wastewater cooling device is adapted to exchange heat with wastewater at a first temperature to cool the wastewater at the first temperature to a second temperature before outputting it.

[0012] In one embodiment, the second wastewater cooling device is adapted to exchange heat with wastewater at a second temperature to cool the wastewater at the second temperature to a third temperature before outputting it.

[0013] In one embodiment, the wastewater after being treated by the wastewater cooling assembly has a first temperature > a second temperature > a third temperature.

[0014] In one embodiment, each of the wastewater cooling devices is provided with a backwash filter and a backwash screen. The backwash filter is adapted to be installed at the tube outlet end of the wastewater cooling device, and the backwash screen is adapted to be installed at the tube inlet end of the wastewater cooling device.

[0015] In one embodiment, each of the wastewater cooling devices is provided with a backwashing system, which includes a circulating water inlet pipe and a circulating water return pipe. The circulating water inlet pipe is adapted to be connected to the circulating water inlet of the wastewater cooling device, and the circulating water return pipe is adapted to be connected to the circulating water outlet of the wastewater cooling device, so as to exchange heat with the wastewater via the circulating water.

[0016] In one embodiment, the backwashing system further includes a wastewater backwashing pipe connected to the wastewater cooling device and a drain pipe connected to the wastewater cooling device. The wastewater backwashing pipe is adapted to flow in reverse within the wastewater cooling device to flush the internal pipes of the wastewater cooling device and to discharge impurities from the wastewater cooling device via the drain pipe.

[0017] In one embodiment, the backwashing system further includes a backwash isolation valve disposed at the front end of the backwash filter to isolate the wastewater cooling process of the wastewater cooling device from the backwashing process.

[0018] In one embodiment, the wastewater inlet of the wastewater cooling device is provided with a wastewater inlet valve, the wastewater outlet of the wastewater cooling device is provided with a wastewater outlet valve, and a bypass valve is also provided on the pipeline of the backwash isolation valve. The pipeline where the bypass valve is located is connected in parallel with the pipeline where the wastewater inlet valve is located, so as to maintain the system flow rate during backwashing.

[0019] In the aforementioned urban sludge co-firing wastewater cooling system, a condensation device receives the high-temperature, high-pressure evaporation exhaust gas, initially condensing it into wastewater at a first temperature. Then, the wastewater at the first temperature is gradually cooled by a wastewater cooling component until it reaches the set temperature acceptable to the biological treatment tank before being fed into it. Thus, by setting up multiple wastewater cooling devices to gradually cool the wastewater, the heat exchange efficiency of the cooling system is improved.

[0020] In addition, by installing a backwashing system in each wastewater cooling device, the backwashing system can reduce the adhesion of impurities in each wastewater cooling device, and by regularly backwashing the tubes of the wastewater cooling device, pipe blockage can be effectively avoided, so as to ensure that the heat exchange effect of each wastewater cooling device is not affected, thereby improving the heat exchange efficiency of the overall cooling system. Attached Figure Description

[0021] Figure 1 This is a flowchart of the first type of urban sludge co-firing wastewater cooling system in the embodiments of this application;

[0022] Figure 2 This is a flowchart illustrating the backwashing system of the wastewater cooling device in this application embodiment.

[0023] Explanation of reference numerals in the attached figures:

[0024] 1. Condensation device; 2. Wastewater cooling assembly; 21. First wastewater cooling device; 22. Second wastewater cooling device; 23. Wastewater pump; 3. Biological tank; 4. Circulating water inlet pipe; 5. Circulating water main inlet valve; 6. Circulating water inlet valve; 7. Circulating water return pipe; 8. Circulating water outlet valve; 9. Wastewater backwash pipe; 10. Wastewater backwash valve; 11. Backwash isolation valve; 12. Sewage pipe; 13. Sewage valve; 14. Wastewater inlet pipe; 15. Wastewater inlet valve; 16. Wastewater outlet pipe; 17. Wastewater outlet valve; 18. Bypass valve. Detailed Implementation

[0025] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0026] In the description of this application, it should be understood that if terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" appear, these terms indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0027] Furthermore, where the terms "first" and "second" appear, these terms are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, where the term "multiple" appears, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0028] This application provides a wastewater cooling system for urban sludge co-firing wastewater. This system receives high-temperature, high-pressure evaporation exhaust gas and initially condenses it into wastewater at a first temperature. The wastewater is then gradually cooled by a wastewater cooling assembly 2 until it reaches a set temperature acceptable to a biological treatment tank 3 before being introduced into the tank. Thus, by using multiple wastewater cooling devices to gradually cool the wastewater, the heat exchange efficiency of the cooling system is improved.

[0029] like Figure 1As shown, the urban sludge co-firing wastewater cooling system includes a condensation device 1, a wastewater cooling assembly 2, and a biochemical tank 3. The high-temperature, high-pressure evaporation exhaust gas generated from sludge co-firing enters the condensation device 1, where it exchanges heat with circulating cooling water (or air) to rapidly reduce its temperature to a first temperature and condense into wastewater. During condensation, the condensation device 1 significantly reduces the enthalpy of the high-temperature, high-pressure exhaust gas through the release of latent heat of phase change (gas → liquid). The wastewater, now in a liquid state at the first temperature, then enters the wastewater cooling assembly 2 for secondary cooling. The wastewater cooling assembly 2 consists of multiple wastewater cooling devices connected in series, each of which can be a shell-and-tube heat exchanger or a plate heat exchanger. In this embodiment, to reduce the wastewater at the first temperature to a set temperature (a third temperature), the wastewater at the first temperature needs to be cooled multiple times to ensure the final output temperature is within the set temperature range. After the wastewater at the first temperature is reduced to the set temperature, it can be discharged into the biological treatment tank 3. The biological treatment tank 3 can degrade the input wastewater through activated sludge or biofilm methods.

[0030] Specifically, the wastewater cooling assembly 2 includes a first wastewater cooling device 21 and a second wastewater cooling device 22 connected in series. A wastewater pump 23 is installed between the first wastewater cooling device 21 and the second wastewater cooling device 22. The inlet of the first wastewater cooling device 21 is connected to the outlet of the condenser 1, and the outlet of the first wastewater cooling device 21 is connected to the inlet of the wastewater pump 23. The outlet of the wastewater pump 23 is connected to the inlet of the second wastewater cooling device 22. The wastewater pump 23 can pump the wastewater output from the first wastewater cooling device 21 to the second wastewater cooling device 22 for cooling. It should be noted that the heat exchange area of ​​the first wastewater cooling device 21 and the second wastewater cooling device 22 is the same, and their heat exchange efficiency is basically the same. Furthermore, the wastewater cooling assembly 2 is not limited to having two first wastewater cooling devices 21 and second wastewater cooling devices 22 connected in series; three, four, etc., can also be installed depending on actual needs.

[0031] More specifically, the first wastewater cooling device 21 is adapted to receive wastewater at a first temperature output from the condenser 1. The wastewater at the first temperature undergoes heat exchange within the first wastewater cooling device 21, cooling it to a second temperature before output. Furthermore, a wastewater pump 23, installed between the first and second wastewater cooling devices 21, pumps wastewater at the second temperature from the first device 21 to the second device 22. This wastewater undergoes heat exchange within the second device 22, cooling it to a second temperature before being output to the biological treatment tank 3. The wastewater treated by the wastewater cooling assembly 2 has a first temperature > second temperature > third temperature. Therefore, by controlling the temperature of the wastewater output to the biological treatment tank 3, direct impact of high-temperature wastewater on the biological treatment tank 3 is avoided (temperatures above 40°C inhibit microbial activity), thus improving treatment efficiency.

[0032] like Figure 2 As shown, the cooling medium of the wastewater cooling assembly 2 is circulating water, which has poor water quality and contains a large amount of sludge, dust, and other impurities. These impurities easily settle and accumulate within the wastewater cooling assembly 2. Furthermore, the sludge and dust are highly adhesive, and their adhesion to the heat exchange tube surface, combined with the flow rate of the wastewater cooling assembly 2, significantly increases the heat transfer coefficient and affects its heat transfer efficiency. Therefore, in this embodiment, each wastewater cooling device in the wastewater cooling assembly 2 is equipped with a backwashing system to achieve backwashing functionality and periodically flush the pipes of the wastewater cooling zone to prevent pipe blockage.

[0033] In one embodiment, each wastewater cooling device is equipped with a backwash nozzle (not shown in the figure) and a backwash filter screen (not shown in the figure). The backwash nozzle is adapted to be installed at the tube outlet end of the wastewater cooling device. The backwash nozzle serves as the injection inlet for the flushing medium (water / air) and can guide the flushing medium to flow in the opposite direction to flush the tube side. The backwash filter screen is adapted to be installed at the tube inlet end of the wastewater cooling device to intercept impurities that fall off during the flushing process and prevent the impurities from causing secondary pollution.

[0034] The backwashing system installed in one of the wastewater cooling devices will be described in detail below.

[0035] Specifically, the backwashing system within each wastewater cooling device includes a circulating water system, a wastewater system, a backwashing system, and a sewage discharge system. The circulating water system supplies cooling medium (circulating water) to the wastewater cooling device, reducing its temperature through heat exchange with the wastewater. The wastewater system supplies high-temperature wastewater to the wastewater cooling device, which exchanges heat with the circulating water as it passes through the tubes, achieving cooling. The backwashing system is suitable for introducing flushing medium into the wastewater cooling device. This flushing medium flows counter-currently within the device to clean the tubes and prevent blockages. The sewage discharge system removes impurities and deposits generated during the flushing process.

[0036] More specifically, in the circulating water system of the backwashing system, the circulating water system includes a circulating water inlet pipe 4 and a circulating water return pipe 7. A circulating water inlet main valve 5 is installed on the circulating water inlet pipe 4, and a circulating water inlet valve 6 is also installed on the pipe connecting the circulating water inlet pipe 4 to the circulating water inlet of the wastewater cooling device. The circulating water return pipe 7 is adapted to connect to the circulating water outlet of the wastewater cooling device, and a circulating water outlet valve 8 is installed on the circulating water return pipe 7. The circulating water inlet main valve 5 controls the total flow rate into the wastewater cooling device to regulate the supply of cooling water (circulating water) to the shell side (outside the tubes). During normal cooling operation, the circulating water inlet main valve 5 is fully open, and the circulating water inlet valve 6 and circulating water outlet valve 8 are also fully open to ensure that the circulating water flows sufficiently through the shell side and exchanges heat with the high-temperature wastewater in the tube side. During maintenance or adjustment, the overall flow rate of cooling water into the wastewater cooling device can be adjusted by controlling the opening of the circulating water inlet main valve 5 to adapt to different seasons or load requirements.

[0037] Furthermore, the backwashing system also includes a wastewater backwash pipe 9. The inlet of the wastewater backwash pipe 9 is adapted to connect to the circulating water inlet pipe 4, and the outlet of the wastewater backwash pipe 9 is adapted to connect to the backwash inlet of the wastewater cooling device. A wastewater backwash valve 10 is provided on the wastewater backwash pipe 9. The backwashing system also includes a backwash isolation valve 11, which is located at the front end of the backwash filter to isolate the wastewater cooling process of the wastewater cooling device from the backwashing process. During backwashing operations, the wastewater backwash valve 10 and the backwash isolation valve 11 must be opened simultaneously to ensure unobstructed flow in the flushing channel and avoid localized pressure passages.

[0038] The wastewater cooling device of the sewage system is also equipped with a sewage pipe 12, and a sewage valve 13 is provided on the sewage pipe 12.

[0039] Furthermore, the wastewater system includes a wastewater inlet pipe 14 and a wastewater outlet pipe 16. The wastewater inlet pipe 14 is adapted to connect to the wastewater inlet of the wastewater cooling device, and the wastewater outlet pipe 16 is adapted to connect to the wastewater outlet of the wastewater cooling device. A wastewater inlet valve 15 is provided on the wastewater inlet pipe 14, and a wastewater outlet valve 17 is provided on the wastewater outlet pipe 16. The wastewater connected to the wastewater inlet pipe 14 is suitable for being pumped in by a sewage pump. A bypass valve 18 is also provided on the pipeline of the backwash isolation valve 11. The pipeline where the bypass valve 18 is located is connected in parallel with the pipeline where the wastewater inlet valve 15 is located, so as to maintain the system flow rate during backwashing.

[0040] In one embodiment, during normal cooling, the circulating water inlet valve 6 is open, the circulating water outlet valve 8 is open, the wastewater inlet valve 15 is open, the wastewater outlet valve 17 is open, the wastewater backwash valve 10 is closed, and the drain valve 13 is closed. The flow path of the circulating water is: circulating water main inlet valve 5 - circulating water inlet valve 6 - wastewater cooling device (shell side) - circulating water outlet valve 8; the flow path of the wastewater is: wastewater inlet valve 15 - wastewater cooling device (tube side) - wastewater outlet valve 17. Within the wastewater cooling device, circulating water flows into the shell side, and high-temperature wastewater flows into the tube side. The high-temperature wastewater in the tube side exchanges heat with the circulating water in the shell side to cool the wastewater. Additionally, in case of emergency shutdown, the circulating water main inlet valve 5 can be closed immediately to cut off the circulating water flow, preventing the circulating water in the shell side of the wastewater cooling device from draining and causing the equipment to dry-burn.

[0041] During the backwashing process, wastewater inlet valve 15 is closed, backwash isolation valve 11 is open, bypass valve 18 is open, drain valve 13 is open, and circulating water inlet valve 6 is closed. Therefore, the flow path of the flushing medium during backwashing is: wastewater backwash valve 10 - wastewater cooling device (counter-current flow within the pipe) - drain valve 13. Thus, the flushing medium flows into the pipe of the wastewater cooling device through wastewater backwash valve 10 and flows counter-currently within the device, carrying away impurities flushed down by the device. During the draining process, circulating water inlet valve 6 is closed, drain valve 13 is open, and other valves are closed, finally discharging through drain valve 13. It should be noted that during backwashing, the circulating water flow rate can be reduced or completely shut off to avoid interfering with the normal operation of the backwashing process.

[0042] Furthermore, the wastewater pipe diameter is DN125 > circulating water pipe diameter DN100 > drain pipe diameter DN50, which accommodates the high viscosity and easy sedimentation characteristics of wastewater. Therefore, this wastewater cooling device achieves efficient cooling and anti-clogging functions through a dual design of shell-side heat exchange in circulating water and tube-side backflushing. Each valve controls the medium flow direction through opening and closing combinations, ensuring flexible switching between normal cooling, backflushing, and drain modes. This design periodically removes sediment from the tubes of the wastewater cooling device to maintain its high heat exchange efficiency.

[0043] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0044] In this application, unless otherwise expressly specified and limited, the use of descriptions such as "above" or "below" the second feature indicates that the first and second features are in direct contact or indirect contact via an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. Similarly, "below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0045] It should be noted that if an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. If an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. If so, the terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used in this application are for illustrative purposes only and do not represent the only possible implementation.

[0046] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0047] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A municipal sludge co-combustion waste water cooling system, characterized by, include: A condensing device, the condensing device being adapted to receive evaporation tail gas and condense the evaporation tail gas into wastewater at a first temperature; A wastewater cooling assembly includes multiple wastewater cooling devices connected in series, and each wastewater cooling device is adapted to gradually cool wastewater at a first temperature to a set temperature. A biological treatment tank, which is adapted to receive wastewater that has reached a set temperature output from the wastewater cooling assembly.

2. The urban sludge co-firing wastewater cooling system according to claim 1, characterized in that, The plurality of wastewater cooling devices include a first wastewater cooling device and a second wastewater cooling device connected in series. A wastewater pump is provided between the first wastewater cooling device and the second wastewater cooling device. The inlet of the first wastewater cooling device is connected to the outlet of the condensation device. The outlet of the first wastewater cooling device is connected to the inlet of the wastewater pump. The outlet of the wastewater pump is connected to the inlet of the second wastewater cooling device. The wastewater pump is adapted to pump the wastewater output by the first wastewater cooling device into the second wastewater cooling device.

3. The urban sludge co-firing wastewater cooling system according to claim 2, characterized in that, The first wastewater cooling device is adapted to exchange heat with wastewater at a first temperature to cool the wastewater at the first temperature to a second temperature before outputting it.

4. The urban sludge co-firing wastewater cooling system according to claim 3, characterized in that, The second wastewater cooling device is adapted to exchange heat with wastewater at a second temperature to cool the wastewater at the second temperature to a third temperature before outputting it.

5. The urban sludge co-firing wastewater cooling system according to claim 4, characterized in that, The wastewater, after being treated by the wastewater cooling device, has a first temperature > a second temperature > a third temperature.

6. The urban sludge co-firing wastewater cooling system according to any one of claims 1 to 5, characterized in that, Each of the aforementioned wastewater cooling devices is equipped with a backwash filter and a backwash filter screen. The backwash filter is adapted to be installed at the outlet end of the tube side of the wastewater cooling device, and the backwash filter screen is adapted to be installed at the inlet end of the tube side of the wastewater cooling device.

7. The urban sludge co-firing wastewater cooling system according to claim 6, characterized in that, Each of the aforementioned wastewater cooling devices is equipped with a backwashing system, which includes a circulating water inlet pipe and a circulating water return pipe. The circulating water inlet pipe is adapted to be connected to the circulating water inlet of the wastewater cooling device, and the circulating water return pipe is adapted to be connected to the circulating water outlet of the wastewater cooling device, so as to exchange heat with the incoming wastewater through the circulating water.

8. The urban sludge co-firing wastewater cooling system according to claim 7, characterized in that, The backwashing system also includes a wastewater backwashing pipe connected to the wastewater cooling device and a drain pipe connected to the wastewater cooling device. The wastewater backwashing pipe is adapted to flow in reverse within the wastewater cooling device to flush the internal pipes of the wastewater cooling device and to discharge impurities from the wastewater cooling device via the drain pipe.

9. The urban sludge co-firing wastewater cooling system according to claim 8, characterized in that, The backwashing system also includes a backwashing isolation valve, which is located at the front end of the backwashing filter to isolate the wastewater cooling process of the wastewater cooling device from the backwashing process.

10. The urban sludge co-firing wastewater cooling system according to claim 9, characterized in that, The wastewater cooling device is equipped with a wastewater inlet valve at the wastewater inlet and a wastewater outlet valve at the wastewater outlet. A bypass valve is also provided on the pipeline of the backwash isolation valve. The pipeline where the bypass valve is located is connected in parallel with the pipeline where the wastewater inlet valve is located, so as to maintain the system flow rate during backwashing.

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