Wastewater treatment system combined with waste heat utilization technology

Abstract

The present application belongs to the technical field of wastewater treatment, and relates to a wastewater treatment system combined with waste heat utilization technology, which comprises a heat exchanger for heat exchange between low-temperature waste heat gas and a heat exchange medium, a wastewater treatment device, a solid-liquid separator, a condenser and a vacuum pump. The wastewater treatment device comprises a shell, a filter screen, a flow guide plate and a liquid storage tank arranged in the shell. The filter screen and the flow guide plate divide the inner cavity of the shell into a filtering area, a flow guiding area and a liquid storage area from top to bottom. The liquid storage tank is arranged in the liquid storage area. The vacuum pump is connected to the filtering area. The filtering area is connected to the vacuum pump and the condenser through a gas pipe at the top. The present application can realize the evaporation treatment effect of quickly evaporating wastewater at a low temperature, and can realize the flushing and maintenance of the filter screen structure by using the backflushing effect of the wastewater during liquid spraying evaporation.

Description

Technical Field

[0001] This invention belongs to the field of wastewater treatment technology, specifically relating to a wastewater treatment system that incorporates waste heat utilization technology. Background Technology

[0002] In wastewater treatment technologies, existing evaporation processes consume significant amounts of heat energy, and achieving higher efficiency requires higher temperatures, resulting in high energy consumption and the inability to utilize low-temperature waste heat. Existing technologies employ liquid spraying to disperse the liquid into droplets for accelerated evaporation. While these techniques improve evaporation efficiency and reduce energy consumption to some extent, they necessitate the removal of solid impurities from the liquid, requiring filtration and impurity removal. This adds to the process steps and necessitates regular replacement and maintenance of the filters, impacting treatment efficiency. Furthermore, this technology fails to address the issue of utilizing low-temperature waste heat. Summary of the Invention

[0003] The purpose of this invention is to provide a wastewater treatment system that incorporates waste heat utilization technology, in order to solve the technical problems of the existing technology that requires frequent maintenance of the filtration device and cannot effectively utilize low-temperature waste heat during heating when using liquid spray evaporation for evaporation treatment.

[0004] A wastewater treatment system incorporating waste heat utilization technology includes a heat exchanger for heat exchange between a low-temperature waste heat gas and a heat exchange medium, a wastewater treatment device, a solid-liquid separator, a condenser, and a vacuum pump. The wastewater treatment device includes a shell containing a filter screen, a guide plate, and a liquid storage tank. The filter screen and the guide plate divide the inner cavity of the shell into a filtration zone, a guide zone, and a liquid storage zone from top to bottom. The liquid storage tank is located within the liquid storage zone. The vacuum pump is connected to the filtration zone, which receives wastewater through an inlet. The top of the filtration zone is also connected to the vacuum pump and the condenser via air pipes. The condenser has an inlet at the bottom of the guide plate that allows liquid to flow into the storage tank. A lifting and lowering sealing plate is provided between the guide plate and the storage tank. When the sealing plate rises, it closes the inlet. A dispersing spray structure is provided below the center of the filter screen. The spray direction of the dispersing spray structure is towards the filter screen and is used to wash solid impurities on the filter screen into a concentration tank outside the filter screen. The drain port on the side of the concentration tank is connected to the solid-liquid separator through a pipeline. A spray pump and a heating coil connected to a heat exchanger are provided at the bottom of the storage tank. The spray pump is connected to the nozzle of the dispersing spray structure through a water pipe.

[0005] Preferably, the outer edge of the filter screen is mounted on a conical elastic mounting plate, the outer edge of which is fixed to the inner edge of the concentration tank, which is annular and located at the bottom of the filtration zone; the bottom periphery of the filter screen is connected to the top of the sealing plate via a support plate, which passes through the opening.

[0006] Preferably, in the filtration state, the sealing plate and the filter screen descend together, and the inner edge of the conical elastic mounting plate bends downward to form a funnel-shaped conical surface with the upper rounded edge larger than the lower rounded edge. The wastewater entering the filtration zone is guided to the filter screen by the funnel-shaped conical surface. In the evaporation state, the sealing plate and the filter screen rise together, the sealing plate seals the opening, and the inner edge of the conical elastic mounting plate bends upward to form a conical surface with the upper rounded edge smaller than the lower rounded edge. The inner edge of the conical elastic mounting plate is higher than the bottom of the concentration tank.

[0007] Preferably, the dispersing spray structure includes a plurality of flushing nozzles, a nozzle base, and a rotating connector. The flushing nozzles face obliquely upward, and the plurality of flushing nozzles are circumferentially mounted on the bottom of the nozzle base. The fixed part of the rotating connector is provided with an inlet connected to the fuel injection pump, and the rotating part of the rotating connector is provided with an outlet connected to each flushing nozzle. The projection of the flushing nozzles onto the horizontal plane forms a certain angle with the radial direction of the filter screen.

[0008] Preferably, the guide plate includes an inner conical shell portion and an outer conical shell portion. The upper surface of the inner conical shell portion is a conical surface with an upper circular edge smaller than the lower circular edge, and the upper surface of the outer conical shell portion is a conical surface with an upper circular edge larger than the lower circular edge. The bottom of the guide plate connects the lower circular edges of the inner and outer conical shell portions.

[0009] Preferably, the openings on the guide plate are arc-shaped and arranged circumferentially along its own extension direction, the sealing plate is annular and corresponds to the shape and size of the openings, and a sealing ring is provided on the top of the sealing plate.

[0010] Preferably, the sealing plate is installed at the output end of a vertically arranged electric cylinder, the electric cylinder is installed below the bottom of the liquid storage tank, and the output end passes through the bottom of the liquid storage tank.

[0011] Preferably, an exhaust fan is provided at the top of the filtration zone, and the exhaust fan is located at the inlet of the gas pipe connecting to the condenser.

[0012] The advantages of this invention are as follows: By creating a low-pressure environment and employing a dispersed spraying method for wastewater, this invention achieves rapid evaporation of wastewater at lower temperatures. This utilizes low-temperature waste heat flue gas to evaporate wastewater, maintaining rapid and efficient evaporation even at lower temperatures. Furthermore, dispersed spraying evaporation requires the removal of solid impurities from the wastewater before spraying. This solution combines a filtration structure with the evaporation equipment, utilizing the backwashing effect of the wastewater during spraying evaporation to clean and maintain the filter structure. The change in rinsing direction and the filter and its installation structure also facilitates the transition between filtration and evaporation processes. The conical elastic mounting plate structure simultaneously ensures that the liquid is filtered by the filter in filtration mode and that the concentrate and solid impurities converge in a concentration tank outside the filter in evaporation mode. This allows the concentrate to be discharged without affecting the wastewater in the storage tank during evaporation, while also carrying away solid impurities from the equipment, reducing the frequency of cleaning solid impurities and lowering maintenance costs. The method of heating first, then depressurizing, and then spraying liquid for evaporation can ensure stable heating effect and high evaporation efficiency. It can also avoid the problem of re-contamination of impurities in the flue gas when the flue gas is directly contacted with the liquid droplets for heating and evaporation in the existing technology. There is no need to purify the flue gas with harmful gases and dust before heat exchange. The flue gas can be directly recycled for waste heat through the heat exchanger, reducing heat loss during flue gas purification and making better use of waste heat. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of a wastewater treatment system that incorporates waste heat utilization technology according to the present invention.

[0014] Figure 2 for Figure 1 The diagram shows the structure of the wastewater treatment device.

[0015] Figure 3 for Figure 2 The structure shown is a cross-sectional view along the AA direction.

[0016] Figure 4 for Figure 2 A schematic diagram of the internal structure of the structure shown.

[0017] Figure 5 for Figure 2 A schematic diagram of the dispersion spray structure shown.

[0018] The labels in the attached diagram are as follows: 1. Wastewater treatment device; 101. Shell; 102. Support frame; 103. Electric cylinder; 104. Steam outlet; 105. Exhaust fan; 106. Exhaust port; 107. Water inlet; 108. Drain outlet; 109. Sealing plate; 110. Water pipe; 111. Filtration zone; 112. Guide zone; 113. Storage tank; 114. Guide plate; 115. Dispersing spray structure; 1151. Flushing nozzle; 1152. Nozzle base; 1153. Rotary connector; 116. Filter screen; 117. Spray pump; 118. Concentration tank; 119. Port; 120. Support plate; 121. Conical elastic mounting plate; 122. Heating coil; 2. Heat exchanger; 3. Solid-liquid separator; 4. Condenser; 5. Vacuum pump; 6. Chimney. Detailed Implementation

[0019] The following detailed description of the embodiments, with reference to the accompanying drawings, will further illustrate the specific implementation of the present invention, in order to help those skilled in the art to have a more complete, accurate, and in-depth understanding of the inventive concept and technical solution of the present invention.

[0020] like Figure 1-5 As shown, this invention provides a wastewater treatment system combining waste heat utilization technology, including a heat exchanger 2 for heat exchange between low-temperature waste heat gas and a heat exchange medium, a wastewater treatment device 1 for filtering and evaporating wastewater, a solid-liquid separator 3 for separating solid impurities and concentrated liquid, a condenser 4 for condensing steam, and a vacuum pump 5. The wastewater treatment device 1 includes a housing 101, within which a filter screen 116, a guide plate 114, and a liquid storage tank 113 are provided. The filter screen 116 and the guide plate 114 divide the inner cavity of the housing 101 from top to bottom into a filtration zone 111 and a guide plate 113. The filter includes a storage area 112 and a liquid storage area. The liquid storage tank 113 is located within the liquid storage area. The vacuum pump 5 is connected to the filtration area 111. Wastewater is input into the filtration area 111 through the water inlet 107. The top of the filtration area 111 is also connected to the vacuum pump 5 and the condenser 4 through air pipes. The bottom of the guide plate 114 is provided with an opening 119 for liquid to flow into the liquid storage tank 113. A lifting and lowering sealing plate 109 is provided between the guide plate 114 and the liquid storage tank 113. When the sealing plate 109 rises, it closes the opening 119. A dispersion spray structure 115 is provided below the center of the filter screen 116. The spraying direction of the dispersing spray structure 115 is towards the filter screen 116, and it is used to wash the solid impurities on the filter screen 116 to the concentration tank 118 outside the filter screen 116. The drain port 108 on the side of the concentration tank 118 is connected to the solid-liquid separator 3 through a pipeline. The bottom of the storage tank 113 is provided with a spray pump 117 and a heating coil 122 connected to the heat exchanger 2. The spray pump 117 is connected to the flushing nozzle 1151 of the dispersing spray structure 115 through a water pipe 110.

[0021] The system utilizes heat exchanger 2 to heat the filtered liquid in storage tank 113 to a certain temperature. Before evaporation, the storage tank 113 is separated from the upper guide zone 112 and filter zone 111 by sealing plate 109. The guide zone 112 and filter zone 111 form an evaporation zone during the evaporation process. Then, vacuum pump 5 evacuates the evaporation zone to reduce the pressure to a level that allows the high-temperature liquid in storage tank 113 to evaporate. Next, liquid is sprayed onto filter screen 116 using spray pump 117 and dispersion spray structure 115. The impact force generated by the spray washes away solid impurities and oil stains on filter screen 116. Since the wastewater is heated at this time, it can also quickly melt and solidify the oil stains and impurities on filter screen 116. The solid impurities and oil stains are tilted and washed onto the side wall of filter zone 111 or the concentration tank 118 outside filter screen 116. During this process, the sprayed high-temperature liquid is dispersed in a low-pressure environment, resulting in a large droplet surface area. This allows for rapid evaporation and extraction, while the unevaporated concentrate reaches the sidewall of the filtration zone 111 or the concentration tank 118 outside the filter screen 116 based on kinetic energy. Thus, the system simultaneously achieves backwashing maintenance and evaporation of the filter screen 116. Furthermore, the kinetic energy of the backwashing is used to separate the concentrate from solid impurities, allowing the concentrate containing mixed solid impurities and oil to be discharged through a pipeline to the solid-liquid separator 3 for further processing without affecting the evaporation process.

[0022] The guide plate 114 includes an inner conical shell portion and an outer conical shell portion. The upper surface of the inner conical shell portion is a conical surface with an upper circular edge smaller than the lower circular edge, and the upper surface of the outer conical shell portion is a conical surface with an upper circular edge larger than the lower circular edge. The bottom of the guide plate 114 connects the lower circular edges of the inner and outer conical shell portions. The guide plate 114 guides the filtered liquid into the storage tank 113 through the conical surfaces on both the inner and outer sides.

[0023] The sealing plate 109 is installed at the output end of the vertically positioned electric cylinder 103, which is installed below the bottom of the liquid storage tank 113, with the output end passing through the bottom of the liquid storage tank 113. This allows the sealing plate 109 to be raised and lowered while preventing wastewater from corroding the electric cylinder 103 and avoiding any impact on the heating process. The openings 119 on the guide plate 114 are arc-shaped and arranged circumferentially along its extension direction. The sealing plate 109 is annular and corresponds to the shape and size of the openings 119. A sealing ring is provided at the top of the sealing plate 109. This increases the area and number of openings 119 and facilitates the sealing plate 109 in closing multiple openings 119.

[0024] The dispersion spray structure 115 includes a plurality of flushing nozzles 1151, a nozzle base 1152, and a rotating connector 1153. The flushing nozzles 1151 face obliquely upward, and the plurality of flushing nozzles 1151 are circumferentially mounted on the bottom of the nozzle base 1152. The fixed part of the rotating connector 1153 is provided with an inlet connected to the fuel injection pump, and the rotating part of the rotating connector 1153 is provided with an outlet connected to each flushing nozzle 1151 respectively. The projection of the flushing nozzles 1151 onto the horizontal plane forms a certain angle with the radial direction of the filter screen 116. The dispersion spray structure 115 is mounted on the top of the guide plate 114. The flushing nozzles 1151 are configured in this way so that, on the one hand, solid impurities on the filter screen 116 can be flushed away in an inclined direction, and on the other hand, the rotating parts of the nozzle base 1152 and the rotating connector 1153 can be rotated. In this way, a limited number of flushing nozzles 1151 can automatically rotate around the center of the filter screen 116 during flushing, thereby achieving flushing of each area of ​​the filter screen 116.

[0025] The outer edge of the filter screen 116 is mounted on a conical elastic mounting plate 121, which is fixed to the inner edge of a concentration tank 118, which is annular and located at the bottom of the filtration zone 111. The bottom periphery of the filter screen 116 is connected to the top of the sealing plate 109 via a support plate 120, which passes through the opening 119. This structure allows the filter screen 116 to rise and fall together with the sealing plate 109. In the filtration state, when the sealing plate 109 descends, the filter screen 116 descends along with it, and the inner edge of the conical elastic mounting plate 121 bends downward to form a funnel-shaped conical surface with an upper edge larger than the lower edge. In this state, wastewater entering the filtration zone 111 is guided by the funnel-shaped conical surface to the filter screen 116, where filtration is achieved. During evaporation, the sealing plate 109 rises to seal the opening 119, and the filter screen 116 also rises. The inner edge of the conical elastic mounting plate 121 bends upward to form a conical surface with an upper edge smaller than the lower edge. At this time, the inner edge of the conical elastic mounting plate 121 is higher than the bottom of the concentration tank 118, so that solid impurities, oil stains, and concentrate washed into the concentration tank 118 are temporarily stored in the annular concentration tank 118 and can be discharged from the drain port 108 connected to the concentration tank 118. This prevents the washed substances from flowing through the filter screen 116 again, which would make it difficult to thoroughly clean the filter screen 116.

[0026] A suction fan 105 is provided at the top of the filtration zone 111, and the suction fan 105 is located below the steam outlet 104, which is connected to the condenser 4 via a gas pipe. The suction port 106 at the top of the filtration zone 111 is connected to the vacuum pump 5 via a gas pipe, and each gas pipe is equipped with a switch valve. Thus, when wastewater is sprayed and evaporated, the suction fan 105 quickly extracts and transports the steam to the condenser 4, accelerating steam transport and maintaining a low-pressure environment inside. A support frame 102 is also provided outside the housing 101, and the housing 101 is fixed to the support frame 102. The support frame 102 includes an annular beam plate fixedly connected to the housing 101 and vertically arranged support columns that provide support. The support columns are evenly arranged around the annular beam plate and fixedly connected to it.

[0027] The working process of this invention is as follows: First, substances containing low-temperature waste heat, such as flue gas, exchange heat in the heat exchanger 2 as a heat exchange medium, while wastewater is input into the filtration zone 111 of the wastewater treatment device 1. At this time, the wastewater treatment device 1 is in the filtration state, the sealing plate 109 is in the low position, the opening 119 on the guide plate 114 is opened, the filter screen 116 is in the low position, and the wastewater is transported to the filtration zone 111. Guided by the funnel-shaped conical surface of the conical elastic mounting plate 121 in this state, the wastewater flows into the guide zone 112 after being filtered by the filter screen 116. The filtered wastewater reaches the bottom of the guide plate 114 under the guidance of the guide plate 114, and flows into the storage tank 113 below through the open opening 119. At this time, the heat exchange medium flows to the heating coil 122 to heat the wastewater in the storage tank 113. Since the waste heat being recovered is low-temperature waste heat, the heating coil 122 can only heat the wastewater to 70-80℃, at which point the wastewater cannot evaporate quickly. If the waste heat is recovered from low-temperature flue gas, the flue gas will be discharged or transported to a further flue gas purification system by devices such as the chimney 6 after the waste heat is recovered.

[0028] When the wastewater in the storage tank 113 reaches a certain level, the electric cylinder 103 activates the lifting sealing plate 109 to seal the opening 119. Simultaneously, the filter screen 116 rises, causing the inner edge of the conical elastic mounting plate 121 to bend upwards, forming a conical surface with a smaller upper edge than the lower edge. At this time, the wastewater treatment device 1 enters the evaporation state. First, the vacuum pump 5 evacuates the evaporation zone composed of the filtration zone 111 and the guide zone 112, reducing the pressure to a level where the heated wastewater can evaporate quickly. Then, the vacuum pump 5 and its connected pipeline are shut off. Next, the spray pump 117 is activated, drawing the wastewater from the storage tank 113 and dispersing it from the flushing nozzle 1151. The sprayed liquid backwashes the filter screen 116, and under the impact of the heated wastewater, solid impurities and solidified oil on the upper surface of the filter screen 116 are washed away and melted. Because the flushing nozzle 1151 is tilted, solid impurities, oil, and wastewater are dispersed and flushed toward the outside of the filter screen 116. During this process, the high-temperature wastewater dispersed by the sprayed liquid evaporates rapidly in a low-pressure environment based on the surface area of ​​the dispersed droplets. The evaporated residual liquid, along with solid impurities and oil, converges through the side wall of the filtration zone 111 to the concentration tank 118 at the bottom of the filtration zone 111.

[0029] This simultaneously achieves rapid evaporation of the sprayed wastewater in a low-pressure environment and backwashing of the filter screen 116. The concentrated liquid obtained from the backwashing is guided to the concentration tank 118, thus not affecting the continued spraying and rinsing of the wastewater. The flow of the concentrated liquid carries away most of the solid impurities, avoiding frequent cleaning of the wastewater treatment device 1. The output concentrated liquid is further separated from the solid impurities by a solids separator. The steam generated by the low-pressure evaporation is drawn by the exhaust fan 105 and transported to the condenser 4, where it is condensed and output. Since the steam is formed at a lower temperature in a low-pressure environment, an air pump can be installed at one end of the condenser 4 to further accelerate steam transport. The lower temperature steam is also more likely to condense into liquid water at the condenser 4.

[0030] The present invention has been described above by way of example with reference to the accompanying drawings. Obviously, the specific implementation of the present invention is not limited to the above-described manner. Any non-substantial improvements made using the inventive concept and technical solution of the present invention, or the direct application of the inventive concept and technical solution of the present invention to other occasions without modification, are all within the protection scope of the present invention.

Claims

1. A wastewater treatment system incorporating waste heat utilization technology, characterized in that: The system includes a heat exchanger (2) for heat exchange between a low-temperature waste heat gas and a heat exchange medium, a wastewater treatment device (1), a solid-liquid separator (3), a condenser (4), and a vacuum pump (5). The wastewater treatment device (1) includes a housing (101), which contains a filter screen (116), a guide plate (114), and a liquid storage tank (113). The filter screen (116) and the guide plate (114) guide the housing (101) from top to bottom. The inner cavity of the 01) is divided into a filtration zone (111), a flow guiding zone (112), and a liquid storage zone. The liquid storage tank (113) is located in the liquid storage zone. The vacuum pump (5) is connected to the filtration zone (111). Wastewater is input into the filtration zone (111) through the water inlet (107). The top of the filtration zone (111) is also connected to the vacuum pump (5) and the condenser (4) through air pipes. The bottom of the flow guiding plate (114) is provided to allow liquid to flow. An inlet (119) is provided in the liquid storage tank (113). A lifting and lowering sealing plate (109) is provided between the guide plate (114) and the liquid storage tank (113). When the sealing plate (109) rises, it closes the inlet (119). A dispersing spray structure (115) is provided below the center of the filter screen (116). The spraying direction of the dispersing spray structure (115) is towards the filter screen (116) and is used to disperse the solids on the filter screen (116). The impurities are flushed into the concentration tank (118) outside the filter screen (116). The drain port (108) on the side of the concentration tank (118) is connected to the solid-liquid separator (3) through a pipeline. The bottom of the storage tank (113) is equipped with a spray pump (117) and a heating coil (122) connected to the heat exchanger (2). The spray pump (117) is connected to the flushing nozzle (1151) of the dispersion spray structure (115) through a water pipe (110).

2. The wastewater treatment system combining waste heat utilization technology according to claim 1, characterized in that: The outer edge of the filter screen (116) is mounted on a conical elastic mounting plate (121), and the outer edge of the conical elastic mounting plate (121) is fixed to the inner edge of the concentration tank (118), which is annular and located at the bottom of the filtration zone (111). The bottom periphery of the filter screen (116) is connected to the top of the sealing plate (109) through a support plate (120), which passes through the opening (119).

3. The wastewater treatment system combining waste heat utilization technology according to claim 2, characterized in that: In the filtration state, the sealing plate (109) and the filter screen (116) descend together, and the inner edge of the conical elastic mounting plate (121) bends downward to form a funnel-shaped conical surface with the upper round edge larger than the lower round edge. The wastewater entering the filtration zone (111) is guided to the filter screen (116) by the funnel-shaped conical surface. In the evaporation state, the sealing plate (109) and the filter screen (116) rise together, and the sealing plate (109) seals the opening (119). The inner edge of the conical elastic mounting plate (121) bends upward to form a conical surface with the upper round edge smaller than the lower round edge. The inner edge of the conical elastic mounting plate (121) is higher than the bottom of the concentration tank (118).

4. The wastewater treatment system combining waste heat utilization technology according to claim 1, characterized in that: The dispersion spray structure (115) includes several flushing nozzles (1151), a nozzle base (1152), and a rotating connector (1153). The flushing nozzles (1151) face obliquely upward. Several flushing nozzles (1151) are circumferentially installed at the bottom of the nozzle base (1152). The fixed part of the rotating connector (1153) is provided with an inlet connected to the spray pump (117), and the rotating part of the rotating connector (1153) is provided with an outlet connected to each flushing nozzle (1151). The projection of the flushing nozzles (1151) on the horizontal plane forms a certain angle with the radial direction of the filter screen (116).

5. A wastewater treatment system combining waste heat utilization technology according to claim 1, characterized in that: The guide plate (114) includes an inner conical shell portion and an outer conical shell portion. The upper surface of the inner conical shell portion is a conical surface with an upper circular edge smaller than the lower circular edge. The upper surface of the outer conical shell portion is a conical surface with an upper circular edge larger than the lower circular edge. The bottom of the guide plate (114) is connected to the lower circular edges of the inner conical shell portion and the outer conical shell portion.

6. A wastewater treatment system combining waste heat utilization technology according to claim 5, characterized in that: The opening (119) on the guide plate (114) is arc-shaped and arranged circumferentially along its own extension direction. The sealing plate (109) is annular and corresponds to the shape and size of the opening (119). A sealing ring is provided on the top of the sealing plate (109).

7. A wastewater treatment system combining waste heat utilization technology according to claim 1, characterized in that: The sealing plate (109) is installed at the output end of the vertically arranged electric cylinder (103), which is installed below the bottom of the liquid storage tank (113), and the output end passes through the bottom of the liquid storage tank (113).

8. A wastewater treatment system combining waste heat utilization technology according to claim 1, characterized in that: The top of the filter zone (111) is provided with an exhaust fan (105), which is located below the steam outlet (104). The steam outlet (104) is connected to the condenser (4) through a gas pipe.

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