A cyclone separation integrated device for coal-containing wastewater of a thermal power plant

Abstract

This disclosure provides an integrated cyclone separator for coal-containing wastewater from thermal power plants. The integrated cyclone separator includes a shell, a sludge hopper, and, sequentially arranged within the shell, a gravity cyclone zone, an inclined tube separation zone, a granular filtration zone, and a clear water zone. An inlet pipe is tangentially connected to the side wall of the gravity cyclone zone for cyclone separation of the incoming coal-containing wastewater, causing sludge flocs to flow downwards into the sludge hopper and the clear liquid to flow upwards. The inclined tube separation zone is equipped with inclined tube packing for secondary sedimentation and separation of sludge entrained in the rising clear liquid. The granular filtration zone is filled with granular filter media for filtering and retaining suspended solids in the rising water flow after treatment in the inclined tube separation zone. An outlet collection pipe is also provided within the granular filtration zone for discharging the filtered clear water to the clear water zone. This significantly reduces the footprint and civil engineering investment costs of the coal-containing wastewater treatment system, while also reducing operational complexity.

Description

Technical Field

[0001] The embodiments disclosed herein belong to the field of coal-containing wastewater treatment technology, specifically relating to an integrated cyclone separation device for coal-containing wastewater from thermal power plants. Background Technology

[0002] Currently, thermal power plants generate a large amount of coal-containing wastewater during production and operation. This wastewater mainly comes from seepage water generated by dust suppression spraying in the coal yard, washing wastewater generated by washing the coal conveyor bridge, rainwater in the coal yard, and dust removal drainage from the coal conveying system.

[0003] The volumetric mass of particulate matter in coal-containing wastewater is generally 2.3 g / cm³. 3 After pre-sedimentation in the pre-sedimentation tank, large coal powder particles can be settled. The diameter of the remaining coal powder particles in suspension is less than 0.1 mm. Depending on the type and source of fuel, the amount of coal-containing wastewater, and the sedimentation effect of the pre-sedimentation tank, the mass concentration of suspended solids in coal-containing wastewater from power plants after initial sedimentation is generally between 2000 and 5000 mg / L.

[0004] The main characteristics of coal-containing wastewater are high turbidity and color. The main reason for the significant increase in turbidity and color is the high concentration of suspended solids in the wastewater. In the treatment system of coal-containing wastewater, the key to the selection of treatment process is to remove its main pollutants, suspended solids and color. The designed treatment process will ensure stable and high removal efficiency of suspended solids and color, and ensure that the mass concentration of suspended solids in the effluent is 10-20 mg / L, which meets the requirements for reuse.

[0005] Currently, the main treatment processes used in power plants include chemical coagulation + membrane treatment and high-efficiency microporous ceramic filtration. Among these, chemical coagulation + membrane filtration has high investment and operating costs due to its large water volume; while high-efficiency microporous ceramic filtration has high precision, but fine coal dust can easily cause clogging, requiring frequent backwashing. Summary of the Invention The embodiments disclosed herein aim to at least solve one of the technical problems existing in the prior art, and provide an integrated cyclone separation device for coal-containing wastewater from thermal power plants.

[0006] Embodiments of this disclosure provide an integrated cyclone separator for coal-containing wastewater from thermal power plants, the integrated cyclone separator comprising: case; A sludge hopper, located at the bottom of the housing, is used to collect and discharge sludge. The integrated cyclone separator also includes a gravity cyclone zone, an inclined tube separation zone, a particle filtration zone, and a clear water zone located inside the shell and arranged sequentially from bottom to top along the axial direction of the shell. The gravity vortex zone has an inlet pipe tangentially connected to its sidewall for vortex separation of incoming coal-containing wastewater, causing sludge flocs to flow downwards into the sludge hopper and the clear liquid to flow upwards. The inclined tube separation zone is equipped with inclined tube packing for secondary sedimentation and separation of sludge entrained in the rising clear liquid. The granular filtration zone is filled with granular filter media for filtering and retaining suspended solids in the rising water flow after treatment in the inclined tube separation zone. The granular filtration zone is also equipped with an outlet water collection pipe for discharging the clear water filtered by the granular filter media into the clear water zone.

[0007] Optionally, the top of the housing is provided with a water outlet pipe that connects to the clear water zone; the clear water zone is used to temporarily store the clear water filtered by the particulate filtration zone, and to discharge the clear water temporarily stored in the clear water zone to the outside of the housing through the water outlet pipe.

[0008] Optionally, a plurality of water distribution filter caps are evenly arranged at the bottom of the granular filtration zone for uniform water distribution; the granular filtration zone is arranged sequentially from bottom to top with the water distribution filter caps, the backwash drain collection pipe, and the outlet water collection pipe; The outlet pipe is also used to receive external backwash water and transport it to the clear water zone. The backwash water in the clear water zone enters the granular filtration zone through the outlet water collection pipe to backwash the granular filtration zone. After the backwashing is completed, the backwash water is collected through the backwash drainage water collection pipe and discharged from the shell to the pre-sedimentation tank.

[0009] Optionally, a steady-state guide plate is provided between the inlet pipe and the inclined tube separation zone; the steady-state guide plate is distributed circumferentially along the shell and is inclined to guide the inlet flow of coal-containing wastewater and isolate the flow state of the inclined tube separation zone, so as to maintain the steady state of water flow in the inclined tube separation zone.

[0010] Optionally, the cross-sectional area of ​​the steady-state guide plate increases from its bottom to its top; The inclined tube separation zone also includes an inclined tube bottom support and an inclined tube top anti-buoyancy support located at its bottom and top, respectively, and the inclined tube packing is installed between the inclined tube bottom support and the inclined tube top anti-buoyancy support.

[0011] Optionally, the installation angle of the inclined tube packing is 55°~65°; the upward flow velocity range in the inclined tube separation zone is 3 mm / s~4 mm / s.

[0012] Optionally, the gap range of the water distribution filter cap is 1 mm to 3 mm; The tangential flow velocity in the inlet pipe ranges from 0.6 m / s to 1.0 m / s.

[0013] Optionally, the bottom of the sludge hopper is connected to a sludge discharge pipe, which is connected to an external electrically controlled valve for periodically discharging sludge into the pre-sedimentation tank.

[0014] The integrated cyclone separator for coal-containing wastewater from thermal power plants disclosed in this embodiment has a compact structure, small footprint, stable effluent, and reduces the land area required for coal-containing wastewater treatment, while also reducing operating difficulty and overall investment cost. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the structure of an integrated cyclone separator for coal-containing wastewater from thermal power plants disclosed herein. Detailed Implementation

[0016] To enable those skilled in the art to better understand the technical solutions of this disclosure, the disclosure will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0017] like Figure 1 As shown, an integrated cyclone separator for coal-containing wastewater from thermal power plants is disclosed. The integrated cyclone separator includes a shell 1 and a sludge hopper 2, which is located at the bottom of the shell 1 and is used to collect and discharge sludge. The integrated cyclone separator also includes a gravity cyclone zone 3, an inclined tube separation zone 4, a particle filtration zone 5, and a clear water zone 6, which are located inside the shell 1 and arranged sequentially from the bottom to the top along the axial direction of the shell 1. The gravity vortex zone 3 has an inlet pipe 31 tangentially connected to its side wall for vortex separation of incoming coal-containing wastewater, causing sludge flocs to flow downwards into the sludge hopper 2 and clear liquid to flow upwards. The inclined tube separation zone 4 is equipped with inclined tube packing for secondary sedimentation and separation of sludge entrained in the rising clear liquid. The granular filtration zone 5 is filled with granular filter media 51 for filtering and retaining suspended solids in the rising water flow after treatment in the inclined tube separation zone 4. The granular filtration zone 5 is also equipped with an outlet water collection pipe 52 for discharging the clear water filtered by the granular filter media 51 to the clear water zone 6.

[0018] Specifically, such as Figure 1 As shown, an integrated cyclone separator for coal-containing wastewater from thermal power plants includes a shell 1, and a mud hopper 2, a gravity cyclone zone 3, an inclined tube separation zone 4, a particulate filtration zone 5, and a clear water zone 6 arranged sequentially from bottom to top along the axial direction of the shell 1. This vertically integrated layout highly integrates three water treatment processes—gravity cyclone separation, inclined tube sedimentation separation, and particulate media filtration—within the same shell, significantly reducing the footprint of the coal-containing wastewater treatment system.

[0019] Sludge hopper 2 is located at the bottom of shell 1 and is used to collect and discharge sludge. During the operation of the device, the flocculent sludge generated in gravity cyclone zone 3 and inclined tube separation zone 4 settles into sludge hopper 2 by gravity. Gravity cyclone zone 3 is located above sludge hopper 2, and its side wall is tangentially connected to inlet pipe 31. After pre-sedimentation in the plant's pre-sedimentation tank, coal-containing wastewater is pumped up and subjected to coagulation reaction by adding flocculant in a static mixer. The reacted coal-containing wastewater then enters gravity cyclone zone 3 tangentially through inlet pipe 31. Under the action of tangential water inlet, the coal-containing wastewater forms a swirling flow in gravity cyclone zone 3. Utilizing the combined action of centrifugal force and gravity, the sludge flocs agglomerate and settle into sludge hopper 2 below under gravity, while the separated clear liquid flows upward along the axial direction of shell 1 and enters inclined tube separation zone 4.

[0020] The inclined tube separation zone 4 is located above the gravity vortex zone 3, and is filled with inclined tube packing. The rising clear liquid after separation in the gravity vortex zone 3 enters the inclined tube separation zone 4 from the bottom. Utilizing the principle of shallow sedimentation, the fine sludge particles entrained in the clear liquid are further separated and settled in the inclined tube packing. The settled sludge slides down the inclined tube wall into the sludge hopper 2.

[0021] The granular filtration zone 5 is located above the inclined tube separation zone 4 and is filled with granular filter media 51. The granular filter media 51 can be selected from quartz sand, anthracite, activated carbon, or a combination thereof, and is used for deep filtration of the rising water flow after treatment in the inclined tube separation zone 4, intercepting residual fine suspended solids and colloidal impurities in the water, further reducing the turbidity and color of the effluent. The granular filtration zone 5 is also equipped with an outlet water collection pipe 51, used to collect the clean water filtered by the granular filter media 51 and discharge it to the upper clean water zone 6. The clean water zone 6 is located above the granular filtration zone 5 and is used to receive the clean water discharged from the outlet water collection pipe 52.

[0022] For example, such as Figure 1 As shown, the top of the housing 1 is provided with a water outlet pipe 11 connecting to the clear water zone 6; the clear water zone 6 is used to temporarily store the clear water filtered by the particulate filtration zone 5, and to discharge the clear water temporarily stored in the clear water zone 6 to the outside of the housing 1 through the water outlet pipe 11. The main function of the clear water zone 6 is to temporarily store the clear water filtered by the particulate filtration zone 5, and to discharge the clear water temporarily stored in the clear water zone 6 to the outside of the housing 1 through the water outlet pipe 11, so that it can enter the recycled water tank or the plant's recycled water network. The water outlet pipe 11 is located at the top of the housing 1, and can utilize the liquid level difference in the clear water zone 6 to achieve gravity-fed discharge, reducing power consumption.

[0023] Furthermore, a plurality of water distribution filter caps 53 are evenly arranged at the bottom of the granular filtration zone 5 for uniform water distribution; the granular filtration zone 5 is arranged sequentially from bottom to top with the water distribution filter caps 53, the backwash drainage collection pipe 54, and the outlet water collection pipe 52; the outlet pipe 11 is also used to receive external backwash water and transport it to the clear water zone 6. The backwash water in the clear water zone 6 enters the granular filtration zone 5 through the outlet water collection pipe 52 to backwash the granular filtration zone 5. After the backwash is completed, the backwash water is collected through the backwash drainage collection pipe 54 and discharged from the shell 1 to the pre-sedimentation tank.

[0024] Specifically, such as Figure 1 As shown, in terms of structure, multiple water distribution filter caps 53 are evenly arranged at the bottom of the granular filtration zone 5 to evenly distribute the rising water flow after treatment in the inclined tube separation zone 4, so that the water flow enters the granular filter media layer at a uniform flow rate, avoiding flow deviation or short-circuiting and ensuring filtration effect. From bottom to top, the granular filtration zone 5 is arranged with water distribution filter caps 53, backwash drain collection pipe 54, and outlet water collection pipe 52. Under filtration conditions, the water flow passes from bottom to top through the water distribution filter caps 53 for even distribution, the granular filter media 51 for filtering and intercepting impurities, and the clean water is collected through the outlet water collection pipe 52 and enters the clean water zone 6.

[0025] Regarding backwashing, after the granular filtration zone 5 has been running for a certain period, the suspended solids trapped in the filter layer gradually accumulate, leading to increased filtration resistance. Backwashing is required to restore filtration performance. This device utilizes a pipeline reuse design to achieve seamless switching between filtration and backwashing operations, eliminating the need for a separate backwash water tank and pump. Specifically, the outlet pipe 11 also receives external backwash water (which can be taken from the clean water zone outlet or other clean water sources in the plant area) and transports it to the clean water zone 6. The backwash water in the clean water zone 6 enters the granular filtration zone 5 from top to bottom through the outlet water collection pipe 52 (which also serves as the backwash inlet water distribution pipe), backwashing the granular filter media 51 in the opposite direction to the filtration direction, thus stripping and suspending the impurities trapped in the media. The flow rate of the backwash water is preferably controlled between 15 L / s / m² and 20 L / s / m² to ensure sufficient rinsing intensity to effectively remove impurities, while avoiding excessive flow rate that could lead to filter media loss or damage to the bed structure. After backwashing, the wastewater containing impurities is collected through the backwash drainage collection pipe 54 and discharged from the shell 1 to the pre-sedimentation tank, where it is combined with the raw water in the plant area to enter the next treatment cycle.

[0026] For example, such as Figure 1 As shown, a steady-state guide plate 32 is provided between the water inlet pipe 31 and the inclined tube separation zone 4; the steady-state guide plate 32 is distributed circumferentially along the shell 1 and is inclined to guide the inlet flow of coal-containing wastewater and isolate the flow state of the inclined tube separation zone 4, so as to maintain the steady state of water flow in the inclined tube separation zone 4.

[0027] Specifically, such as Figure 1 As shown, the steady-state guide plate 32 is disposed between the inlet pipe 31 and the inclined tube separation zone 4, distributed circumferentially along the shell 1 and inclined. The steady-state guide plate 32 has a dual function: first, a guiding function—guiding the inlet flow of coal-containing wastewater, so that the rising water flow above the gravity vortex zone 3 completes the transition from a rotating flow state to a stable rising flow state before entering the inclined tube separation zone 4; second, an isolation function—effectively separating the swirling flow state of the lower gravity vortex zone 3 from the laminar flow state of the upper inclined tube separation zone 4, preventing the swirling flow from disturbing the steady state of the water flow in the inclined tube separation zone 4, thereby ensuring the shallow sedimentation efficiency of the inclined tube separation zone 4. It can be understood that the arrangement of the steady-state guide plate 32 allows the two processes with different flow state requirements, swirling separation and inclined tube sedimentation, to be arranged vertically adjacent to each other in the same shell without interfering with each other, which is one of the key structures for realizing the integration of the device.

[0028] Furthermore, the cross-sectional area of ​​the steady-state guide plate 32 increases from its bottom to its top; the inclined tube separation zone 4 also includes inclined tube bottom supports and inclined tube top anti-buoyancy supports (not labeled) located at its bottom and top, respectively, and the inclined tube packing is installed between the inclined tube bottom supports and the inclined tube top anti-buoyancy supports. The cross-sectional area of ​​the steady-state guide plate 32 increases from its bottom to its top, that is, it has a funnel or cone-shaped structure that is larger at the top and smaller at the bottom. This shape design makes the flow velocity of the rising water gradually decrease when it flows through the steady-state guide plate 32 area, which is conducive to the smooth transition of the water flow to the laminar flow state required by the inclined tube separation zone 4, while providing sufficient inlet cross-sectional area for the inclined tube separation zone 4.

[0029] The inclined tube separation zone 4 also includes a bottom support and a top anti-buoyancy bracket located at its bottom and top, respectively. The inclined tube packing is installed between the bottom support and the top anti-buoyancy bracket. The bottom support is used to bear the weight of the inclined tube packing and the load of water flow and sludge during operation; the top anti-buoyancy bracket is used to prevent the inclined tube packing from floating and shifting under the action of rising water flow, ensuring the installation angle and structural stability of the inclined tube packing.

[0030] Furthermore, the installation angle of the inclined tube packing is 55°~65°; the upward flow velocity range within the inclined tube separation zone 4 is 3 mm / s~4 mm / s. The installation angle of the inclined tube packing is preferably set to 60°. This angle range ensures that sludge particles settled on the inclined tube wall overcome the drag force of the water flow and smoothly slide into the sludge hopper 2 below under the action of gravity, avoiding sludge accumulation and blockage on the inclined tube wall, while providing sufficient effective settling area to ensure effluent quality. The upward flow velocity range within the inclined tube separation zone 4 is controlled between 3 mm / s and 4 mm / s. This velocity range is determined based on the settling characteristics of fine coal powder particles (generally less than 0.1 mm in diameter) in coal-containing wastewater, ensuring sufficient settling time for fine sludge particles within the inclined tube packing, maintaining high sedimentation and separation efficiency while ensuring treatment capacity and hydraulic load.

[0031] For example, such as Figure 1 As shown, the gap range of the water distribution filter cap 53 is 1 mm to 3 mm; the tangential flow velocity range in the water inlet pipe 31 is 0.6 m / s to 1.0 m / s. The gap range of the water distribution filter cap 53 is controlled within 1 mm to 3 mm, and the specific gap value is selected according to the actual outer diameter of the granular filter medium 51 filled in. This gap range ensures that the water flows evenly through the water distribution filter cap 53 and enters the granular filter medium layer upwards, while effectively preventing the granular filter medium 51 from leaking out of the gaps in the water distribution filter cap 53, thus avoiding filter medium loss and blockage of the water distribution system.

[0032] The tangential flow velocity in the inlet pipe 31 is controlled within the range of 0.6 m / s to 1.0 m / s. This velocity range was determined after comprehensively considering the cyclone separation efficiency and floc integrity: if the velocity is too low, the cyclone power is insufficient, the centrifugal separation effect is poor, and the sludge flocs cannot effectively clump together towards the center; if the velocity is too high, the shear force is too large, and the already formed sludge flocs are easily broken into fine particles, which reduces the removal efficiency of subsequent inclined tube separation and filtration. Within this velocity range, the device can maintain the integrity of the sludge flocs while ensuring sufficient cyclone separation effect.

[0033] For example, such as Figure 1 As shown, a sludge discharge pipe 21 is connected to the bottom of the sludge hopper 2. The sludge discharge pipe 21 is connected to an external electrically controlled valve for periodically discharging sludge into the pre-sedimentation tank. In actual operation, the external electrically controlled valve can be periodically opened via a PLC or DCS control system. The sludge settled in the sludge hopper 2 in the gravity vortex zone 3 and the inclined tube separation zone 4 is automatically discharged into the pre-sedimentation tank through the sludge discharge pipe 21 under hydrostatic pressure, achieving fully automated sludge discharge. The sludge discharge cycle can be flexibly set according to the actual influent suspended solids concentration and sludge production, for example, sludge can be discharged every 4 to 8 hours, with each discharge lasting 1 to 3 minutes, to ensure that the sludge in the sludge hopper 2 does not accumulate excessively and affect the normal operation of the device.

[0034] The cyclone separation integrated device for coal-containing wastewater from thermal power plants disclosed in this embodiment integrates three processes—cyclone separation, inclined tube sedimentation, and granular media filtration—within a single housing, forming a bottom-up, vertically integrated structure. Compared to traditional split-type process routes, this significantly reduces the footprint and civil engineering investment costs of the coal-containing wastewater treatment system, while also lowering operational complexity. The entire device has no other expensive or easily damaged parts; only the granular filter media needs to be replaced periodically every 2-3 years to maintain long-term stable operation, resulting in low maintenance costs. The device has simple operating steps, and the entire process can be automated. The effluent suspended solids concentration can be stably controlled between 10 mg / L and 20 mg / L, with an overall suspended solids removal rate and decolorization efficiency both exceeding 95%, meeting the water quality requirements for the reuse of coal-containing wastewater from thermal power plants.

[0035] It is understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of this disclosure, and this disclosure is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and substance of this disclosure, and these modifications and improvements are also considered to be within the scope of protection of this disclosure.

Claims

1. An integrated hydrocyclone separation device for coal-containing wastewater from thermal power plants, characterized in that, The integrated cyclone separator includes: case; A sludge hopper, located at the bottom of the housing, is used to collect and discharge sludge; The integrated cyclone separator also includes a gravity cyclone zone, an inclined tube separation zone, a particle filtration zone, and a clear water zone located inside the shell and arranged sequentially from bottom to top along the axial direction of the shell. The gravity vortex zone has an inlet pipe tangentially connected to its sidewall for vortex separation of incoming coal-containing wastewater, causing sludge flocs to flow downwards into the sludge hopper and clear liquid to flow upwards. The inclined tube separation zone is equipped with inclined tube packing for secondary sedimentation and separation of sludge entrained in the rising clear liquid. The granular filtration zone is filled with granular filter media for filtering and retaining suspended solids in the rising water flow after treatment in the inclined tube separation zone. The granular filtration zone is also equipped with an outlet water collection pipe for discharging the clear water filtered by the granular filter media into the clear water zone.

2. The integrated hydrocyclone separation device for coal-containing wastewater from thermal power plants according to claim 1, characterized in that, The top of the housing is provided with a water outlet pipe that connects to the clear water zone; the clear water zone is used to temporarily store the clear water filtered by the particulate filtration zone, and to discharge the clear water temporarily stored in the clear water zone to the outside of the housing through the water outlet pipe.

3. The integrated hydrocyclone separation device for coal-containing wastewater from thermal power plants according to claim 1, characterized in that, The bottom of the granular filtration zone is evenly provided with multiple water distribution filter caps for uniform water distribution; the granular filtration zone is provided with the water distribution filter caps, the backwash drain collection pipe and the outlet water collection pipe in sequence from the bottom to the top. The outlet pipe is also used to receive external backwash water and transport it to the clear water zone. The backwash water in the clear water zone enters the granular filtration zone through the outlet water collection pipe to backwash the granular filtration zone. After the backwashing is completed, the backwash water is collected through the backwash drainage water collection pipe and discharged from the shell to the pre-sedimentation tank.

4. The integrated hydrocyclone separator for coal-containing wastewater from thermal power plants according to any one of claims 1 to 3, characterized in that, A steady-state guide plate is provided between the inlet pipe and the inclined tube separation zone; the steady-state guide plate is distributed circumferentially along the shell and is inclined to guide the inlet flow of coal-containing wastewater and isolate the flow state of the inclined tube separation zone, so as to maintain the steady state of water flow in the inclined tube separation zone.

5. The integrated hydrocyclone separation device for coal-containing wastewater from thermal power plants according to claim 4, characterized in that, The cross-sectional area of ​​the steady-state guide plate increases from its bottom to its top. The inclined tube separation zone also includes an inclined tube bottom support and an inclined tube top anti-buoyancy support located at its bottom and top, respectively, and the inclined tube packing is installed between the inclined tube bottom support and the inclined tube top anti-buoyancy support.

6. The integrated hydrocyclone separation device for coal-containing wastewater from thermal power plants according to claim 5, characterized in that, The installation angle of the inclined tube packing is 55°~65°; the upward flow velocity range in the inclined tube separation zone is 3 mm / s~4 mm / s.

7. The integrated hydrocyclone separation device for coal-containing wastewater from thermal power plants according to claim 3, characterized in that, The gap range of the water distribution filter cap is 1 mm to 3 mm; The tangential flow velocity in the inlet pipe ranges from 0.6 m / s to 1.0 m / s.

8. The integrated hydrocyclone separation device for coal-containing wastewater from thermal power plants according to claim 1, characterized in that, The bottom of the sludge hopper is connected to a sludge discharge pipe, which is connected to an external electrically controlled valve for discharging sludge into the pre-sedimentation tank at regular intervals.

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