High-salt wastewater zero discharge system

Abstract

This utility model relates to the field of wastewater treatment technology, and in particular to a zero-discharge system for high-salinity wastewater, comprising an evaporator, a concentration tower, and an atomizing pipeline. The evaporator is arranged vertically, with its top connected to the flue gas outlet of a selective catalytic reduction system, and its bottom connected to an ash discharge pipeline. The concentration tower contains a concentration cavity, the bottom of which is connected to a high-salinity wastewater source. A heat exchange pipeline is installed within the concentration cavity, with one end connected to the bottom of the evaporator and the other end extending out of the concentration tower, so that the high-salinity wastewater evaporates and concentrates within the concentration cavity to form a concentrated liquid. One end of the atomizing pipeline is connected to the concentration cavity, and the other end is connected to the top of the evaporator to transport the concentrated liquid to the evaporator.

Description

Technical Field

[0001] This utility model relates to the technical field of wastewater treatment, and in particular to a zero-discharge system for high-salinity wastewater. Background Technology

[0002] Currently, wastewater from coal-fired power plants both domestically and internationally generally utilizes a "pretreatment + concentration and reduction + end-of-pipe solidification" process to achieve efficient utilization and zero wastewater discharge. Concentration and reduction include processes such as thermal concentration and membrane concentration. Thermal concentration, depending on the heat source used, mainly includes low-temperature flue gas concentration and steam multi-effect concentration. End-of-pipe solidification technologies have various types, including main flue gas evaporation technology and bypass flue gas evaporation technology, with bypass flue gas evaporation technology being the most widely used currently.

[0003] The commonly used low-temperature flue gas concentration bypass evaporation technology system draws low-temperature flue gas from before the desulfurization tower to a low-temperature flue gas concentration tower where it comes into countercurrent contact with high-salt wastewater for heat exchange, thus concentrating the wastewater. The clean water produced by evaporation and concentration is captured by the desulfurization system. The concentrated liquid is then pumped to a bypass evaporation tower for further evaporation and drying, achieving zero wastewater discharge.

[0004] However, the dust collector outlet flue gas temperature of the low-temperature economizer retrofit unit is reduced to below 90°C, which cannot meet the operating requirements of the low-temperature flue gas concentration tower, making it difficult to apply the existing low-temperature flue gas concentration bypass flue gas evaporation technology system. Utility Model Content

[0005] The purpose of this utility model is to provide a zero-discharge system for high-salt wastewater to solve the technical problem that in the existing technology, the dust collector outlet flue gas temperature of the low-temperature economizer retrofit unit is reduced to below 90°C, which cannot meet the operation requirements of the low-temperature flue gas concentration tower, and it is difficult to apply the existing low-temperature flue gas concentration bypass flue gas evaporation technology system.

[0006] In the first aspect, the present invention provides a zero-discharge system for high-salt wastewater, including an evaporator, a concentration tower, and an atomizing pipeline;

[0007] The evaporator is arranged vertically, the top of the evaporator is used to connect with the flue gas outlet pipe of the selective catalytic reduction system, and the bottom of the evaporator is provided with an ash discharge pipe;

[0008] The concentration tower is provided with a concentration cavity. The bottom of the concentration cavity is used to connect with the discharge source of high-salt wastewater. The concentration cavity is provided with a heat exchange pipeline. One end of the heat exchange pipeline is connected to the bottom of the evaporator, and the other end of the heat exchange pipeline extends out of the concentration tower so that the high-salt wastewater is evaporated and concentrated in the concentration cavity to form a concentrated liquid.

[0009] One end of the atomizing pipe is connected to the concentration cavity, and the other end of the atomizing pipe is connected to the top of the evaporator to deliver the concentrate to the evaporator.

[0010] Furthermore, the high-salinity wastewater zero-discharge system also includes a circulation pipeline, which has a spray pipeline, nozzles, and a concentrate circulation pump;

[0011] The circulation pipeline is located between the concentration cavity and the atomization pipeline and is connected to the atomization pipeline. Several nozzles are evenly spaced at the top of the concentration cavity. One end of the spray pipeline is connected to the nozzle, and the other end of the spray pipeline is connected to the bottom of the concentration cavity. The concentrate circulation pump is located in the spray pipeline.

[0012] Furthermore, an atomizing water pump and a concentrated water tank are provided on the atomizing pipeline. The concentrated water tank is located between the atomizing water pump and the spray pipeline. The concentrated water tank is used to contain the concentrated liquid, and the atomizing water pump is used to atomize the concentrated liquid into mist.

[0013] Furthermore, the high-salinity wastewater zero-discharge system also includes an air branch, and the evaporator also includes nozzles;

[0014] One end of the air branch is provided with a compressed air storage tank, and the other end of the air branch is connected to the nozzle. The atomizing pipeline is connected to the nozzle so that the atomized concentrate is mixed with the compressed air.

[0015] Furthermore, the high-salinity wastewater zero-discharge system also includes a dust collector;

[0016] The dust collector is located between the evaporator and the concentration tower, and is connected to both the evaporator and the concentration tower.

[0017] Furthermore, the high-salinity wastewater zero-discharge system also includes a pretreatment water pump and a pretreatment device;

[0018] One end of the pretreatment water pump is connected to the discharge source of high-salt wastewater, and the other end of the pretreatment water pump is connected to one end of the pretreatment device, and the other end of the pretreatment device is connected to the concentration tower.

[0019] Compared with existing technologies, this utility model provides a zero-discharge system for high-salinity wastewater, including an evaporator, a concentration tower, and an atomizing pipeline. The evaporator is vertically arranged, with its top connected to the flue gas outlet of a selective catalytic reduction system and its bottom connected to an ash discharge pipeline. The concentration tower contains a concentration cavity, the bottom of which is connected to a high-salinity wastewater source. A heat exchange pipeline is installed within the concentration cavity, with one end connected to the bottom of the evaporator and the other end extending out of the concentration tower, allowing the high-salinity wastewater to evaporate and concentrate within the concentration cavity to form a concentrated liquid. One end of the atomizing pipeline is connected to the concentration cavity. The other end of the atomizing pipeline is connected to the top of the evaporator to transport the concentrate to the evaporator. The evaporator uses the high-temperature flue gas from the selective catalytic reduction system as a heat source to evaporate the high-salt wastewater concentrate into ash. At the same time, the low-temperature flue gas after evaporation is transported to the heat exchange pipeline of the concentration tower to exchange heat with the high-salt wastewater in the concentration cavity, thereby concentrating the high-salt wastewater into a concentrate. The concentrate is then atomized and transported to the evaporator for evaporation by the atomizing pipeline. This solves the technical problem that the dust collector outlet flue gas temperature of the existing low-temperature economizer retrofit unit is reduced to below 90℃, which cannot meet the operation requirements of the low-temperature flue gas concentration tower, and makes it difficult to apply the existing low-temperature flue gas concentration bypass flue gas evaporation technology system. Attached Figure Description

[0020] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0021] Figure 1 A schematic diagram of the overall structure of the zero-discharge system for high-salinity wastewater provided in this embodiment of the utility model;

[0022] Figure 2 This is a schematic diagram of the heat exchange pipeline in the zero-discharge system for high-salt wastewater provided in this embodiment of the present invention.

[0023] Figure label:

[0024] 100. Evaporator; 110. Smoke outlet pipe; 120. Ash discharge pipe; 130. Nozzle;

[0025] 200. Concentration tower; 210. Concentration cavity; 220. Heat exchange piping;

[0026] 300. Atomizing pipeline; 310. Atomizing water pump; 320. Concentrated water tank;

[0027] 400. Circulation pipeline; 410. Spray pipeline; 420. Spray nozzle; 430. Concentrate circulation pump;

[0028] 500. Air branch line; 510. Compressed air storage tank;

[0029] 600. Dust collector;

[0030] 700. Pretreatment water pump;

[0031] 800. Pretreatment device. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. The components of the embodiments of this utility model described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0033] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0034] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0035] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product is in use. They are used only for the convenience of describing this utility model 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. Therefore, they should not be construed as limitations on this utility model. Furthermore, the terms "first," "second," and "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0036] Furthermore, terms such as "horizontal," "vertical," and "sag" do not imply that components must be absolutely horizontal or suspended, but rather that they can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal relative to "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0037] In the description of this utility model, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; 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; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0038] The following detailed description, in conjunction with the accompanying drawings, outlines some embodiments of the present invention. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0039] like Figure 1 and Figure 2 As shown in the figure, this utility model embodiment provides a zero-discharge system for high-salinity wastewater, including an evaporator 100, a concentration tower 200, and an atomizing pipeline 300. The evaporator 100 is arranged vertically, and its top is used to connect with the flue gas outlet pipeline 110 of a selective catalytic reduction system. An ash discharge pipeline 120 is provided at the bottom of the evaporator 100. A concentration cavity 210 is provided inside the concentration tower 200, and its bottom is used to connect with a high-salinity wastewater source. A heat exchange pipeline 220 is provided inside the concentration cavity 210. One end of the heat exchange pipeline 220 is connected to the bottom of the evaporator 100, and the other end of the heat exchange pipeline 220 extends out of the concentration tower 200, so that the high-salinity wastewater is evaporated and concentrated in the concentration cavity 210 to form a concentrated liquid. One end of the atomizing pipeline 300 is connected to the concentration cavity 210, and the other end of the atomizing pipeline 300 is connected to the top of the evaporator 100 to transport the concentrated liquid to the evaporator 100.

[0040] That is, the high-salt wastewater zero-discharge system provided by this utility model uses the high-temperature flue gas of the selective catalytic reduction system as a heat source in the evaporator 100 to evaporate the high-salt wastewater concentrate into ash. At the same time, the low-temperature flue gas after evaporation is transported to the heat exchange pipe 220 of the concentration tower 200 to exchange heat with the high-salt wastewater in the concentration cavity 210, thereby concentrating the high-salt wastewater into a concentrate. The concentrate is then atomized and transported to the evaporator 100 for evaporation by the atomization pipe 300. This solves the technical problem that in the prior art, the outlet flue gas temperature of the dust collector 600 of the low-temperature economizer retrofit unit is reduced to below 90°C, which cannot meet the operating requirements of the low-temperature flue gas concentration tower 200, and it is difficult to apply the existing low-temperature flue gas concentration bypass flue evaporation technology system.

[0041] Specifically, the high-salinity wastewater zero-discharge system provided in this embodiment includes an evaporator 100, a concentration tower 200, and an atomizing pipeline 300. The concentration tower 200 is specifically configured as a hollow tank with a concentration cavity 210 inside. A heat exchange pipeline 220 is installed within the concentration cavity 210, connecting to the discharge source of the high-salinity wastewater at the bottom of the concentration tower 200 via a pipeline. This allows the high-salinity wastewater to be introduced into the concentration cavity 210 for heat exchange and evaporation with the heat exchange pipeline 220, evaporating the water in the high-salinity wastewater and converting it into a concentrated liquid. In this embodiment, the heat exchange pipeline 220 consists of multiple parallel-connected coils arranged in a circular coil within the concentration cavity 210. The concentration cavity 210 is connected to the top of the evaporator 100 via the atomizing pipeline 300, which atomizes the concentrated liquid and delivers it into the evaporator 100. Evaporator 100 is vertically oriented, with its top connected to the outlet flue of SCR (Selective Catalytic Reduction). The SCR outlet flue discharges high-temperature flue gas at approximately 350-380°C. This high-temperature flue gas evaporates and crystallizes the atomized concentrate. A portion of the resulting ash falls onto the ash discharge pipe 120 at the bottom of evaporator 100, controlled by a pneumatic valve to remove the ash. The remaining ash is discharged along with the evaporated and crystallized flue gas into the heat exchange pipe 220 within the concentration chamber 210. The evaporated and crystallized flue gas is the low-temperature flue gas at the tail end of evaporator 100, with a temperature of 180-220°C, which fully meets the heat exchange requirements of the high-salt wastewater in concentration tower 200. Therefore, the waste heat from the low-temperature flue gas at the tail end of evaporator 100 can be used to achieve heat exchange and evaporation of the high-salt wastewater in concentration tower 200.

[0042] Preferably, the high-salinity wastewater zero-discharge system further includes a pretreatment pump 700 and a pretreatment device 800; one end of the pretreatment pump 700 is connected to the high-salinity wastewater source, the other end of the pretreatment pump 700 is connected to one end of the pretreatment device 800, and the other end of the pretreatment device 800 is connected to the concentration tower 200.

[0043] Specifically, high-salinity wastewater is pumped to pretreatment unit 800 via a pretreatment feedwater pump. Pretreatment unit 800 can be one or more of the following: high-density sedimentation tank, chemical crystallization granulation fluidized bed, mechanically accelerated stirring clarification tank, and triple-tank process. Pretreatment unit 800 reduces the hardness and suspended solids of the wastewater, resulting in effluent from pretreatment unit 800 with suspended solids ≤10mg / L, hardness <1mmol / L, and alkalinity <1mmol / L. The high-salinity wastewater produced by pretreatment unit 800 is then pumped to concentration chamber 210 via a feedwater pump from concentration tower 200 for evaporation and concentration.

[0044] Furthermore, the zero-discharge system for high-salt wastewater also includes a dust collector 600; the dust collector 600 is located between the evaporator 100 and the concentration tower 200, and is connected to both the evaporator 100 and the concentration tower 200.

[0045] Specifically, the dust collector is installed between the connecting pipes of the evaporator 100 and the concentration tower 200, and is connected to the evaporator 100 and the concentration tower 200 respectively through the connecting pipes. The dust collector 600 can remove ash from the low-temperature flue gas at the tail end.

[0046] Furthermore, the atomizing pipeline 300 also includes a circulation pipeline, which has a spray pipeline 410, a nozzle 420, and a concentrate circulation pump 430. The circulation pipeline is located between the concentration cavity 210 and the atomizing pipeline 300 and is connected to the atomizing pipeline 300. Several nozzles 420 are evenly spaced at the top of the concentration cavity 210. One end of the spray pipeline 410 is connected to the nozzle 420, and the other end of the spray pipeline 410 is connected to the bottom of the concentration cavity 210. The concentrate circulation pump 430 is located in the spray pipeline 410.

[0047] Specifically, the circulation pipeline consists of a spray pipe 410, nozzles 420, and a concentrate circulation pump 430. The other end of the spray pipe 410 is connected to the bottom of the concentration cavity 210, and the inlet of the spray pipe 410 is located above the high-salt wastewater inlet. The main body of the spray pipe 410 is located outside the concentration cavity 210 and extends upwards, while the other end of the spray pipe 410 extends into the concentration cavity 210 and extends horizontally. Multiple nozzles 420 are evenly spaced and fixed below the spray pipe 410 extending into the concentration cavity 210, thereby re-transporting the incompletely concentrated high-salt wastewater back to the top of the concentration cavity 210 for downward spraying, where it again exchanges heat with the heat exchange pipe 220. A steam discharge pipe is installed at the top of the concentration tower 200, which is connected to the condensation tower. This allows the steam generated during heat exchange evaporation to be discharged into the condensation tower. The condensation tower can be equipped with air-cooled or water-cooled components to condense the evaporated water vapor into liquid water for recycling. An electric valve is installed on the circulation pipeline. One end of the electric valve is connected to the circulation pipeline, and the other end is connected to the atomization pipeline 300. After the high-salt wastewater has been evaporated and the concentrate is not concentrated, the electric valve can be switched to connect the circulation pipeline to the atomization pipeline 300. Instead of re-feeding the concentrate to the top of the concentration chamber 210, the concentrate is fed into the atomization pipeline 300, thus preparing it for delivery to the evaporator 100.

[0048] Preferably, an atomizing water pump 310 and a concentrate tank 320 are provided on the atomizing pipeline 300. The concentrate tank 320 is located between the atomizing water pump 310 and the spray pipeline 410. The concentrate tank 320 is used to contain the concentrate, and the atomizing water pump 310 is used to atomize the concentrate into mist.

[0049] Specifically, a concentrate tank 320 is located between the atomizing water pump 310 and the spray pipe 410, and is connected to electric valves on both the atomizing water pump 310 and the spray pipe 410 via a pipe. The concentrate tank 320 is used to hold the concentrate, while the atomizing water pump 310 draws the concentrate for atomization. A frequency converter is installed on the atomizing water pump 310 to control it, and a flow meter is installed on the atomization pipe 300 to record the flow rate of the concentrate, providing data support for subsequent precise control of the atomization ratio.

[0050] Furthermore, the high-salt wastewater zero-discharge system also includes an air branch 500, and the evaporator 100 also includes a nozzle 130; one end of the air branch 500 is provided with a compressed air storage tank 510, and the other end of the air branch 500 is connected to the nozzle 130, and the atomizing pipeline 300 is connected to the nozzle 130 so that the atomized concentrate is mixed with the compressed air.

[0051] Specifically, nozzle 130 is disposed on the top housing of evaporator 100 and extends outside evaporator 100. Air branch 500 and atomizing pipeline 300 are connected in parallel to nozzle 130. Air branch 500 is provided with compressed air tank, pneumatic valve and check valve, so as to deliver compressed air into nozzle 130 and mix and atomize it with compressed liquid delivered into nozzle 130 by atomizing pipeline 300. In this embodiment, the gas-liquid ratio of compressed liquid to compressed air is 140-160. The compressed air in compressed air tank can be prepared by air compressor.

[0052] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this utility model.

Claims

1. A zero-discharge system for high-salinity wastewater, characterized in that, Includes an evaporator (100), a concentration tower (200), and an atomizing pipeline (300); The evaporator (100) is arranged vertically, the top of the evaporator (100) is used to connect with the flue gas outlet pipe (110) of the selective catalytic reduction system, and the bottom of the evaporator (100) is provided with an ash discharge pipe (120). The concentration tower (200) is provided with a concentration cavity (210). The bottom of the concentration cavity (210) is used to connect with the discharge source of high-salt wastewater. The concentration cavity (210) is provided with a heat exchange pipe (220). One end of the heat exchange pipe (220) is connected to the bottom of the evaporator (100), and the other end of the heat exchange pipe (220) extends out of the concentration tower (200) so that the high-salt wastewater is evaporated and concentrated in the concentration cavity (210) to form a concentrated liquid. One end of the atomizing conduit (300) is connected to the concentration cavity (210), and the other end of the atomizing conduit (300) is connected to the top of the evaporator (100) to deliver the concentrate to the evaporator (100).

2. The zero-discharge system for high-salinity wastewater according to claim 1, characterized in that, The high-salt wastewater zero-discharge system also includes a circulation pipeline, which has a spray pipeline (410), a nozzle (420) and a concentrate circulation pump (430); The circulation pipeline is located between the concentration cavity (210) and the atomizing pipeline (300) and is connected to the atomizing pipeline (300). A plurality of nozzles (420) are evenly spaced at the top of the concentration cavity (210). One end of the spray pipeline (410) is connected to the nozzle (420), and the other end of the spray pipeline (410) is connected to the bottom of the concentration cavity (210). The concentrate circulation pump (430) is located in the spray pipeline (410).

3. The zero-discharge system for high-salinity wastewater according to claim 2, characterized in that, An atomizing water pump (310) and a concentration tank (320) are provided on the atomizing pipeline (300). The concentration tank (320) is located between the atomizing water pump (310) and the spray pipeline (410). The concentration tank (320) is used to contain the concentrate, and the atomizing water pump (310) is used to atomize the concentrate into mist.

4. The zero-discharge system for high-salinity wastewater according to claim 3, characterized in that, The high-salinity wastewater zero-discharge system also includes an air branch (500), and the evaporator (100) also includes a nozzle (130); One end of the air branch (500) is provided with a compressed air storage tank (510), and the other end of the air branch (500) is connected to the nozzle (130). The atomizing pipeline (300) is connected to the nozzle (130) so that the atomized concentrate is mixed with the compressed air.

5. The zero-discharge system for high-salinity wastewater according to any one of claims 1-4, characterized in that, The zero-discharge system for high-salinity wastewater also includes a dust collector (600); The dust collector (600) is disposed between the evaporator (100) and the concentration tower (200), and the dust collector (600) is connected to the evaporator (100) and the concentration tower (200) respectively.

6. The zero-discharge system for high-salinity wastewater according to any one of claims 1-4, characterized in that, The zero-discharge system for high-salinity wastewater also includes a pretreatment water pump (700) and a pretreatment device (800); One end of the pretreatment water pump (700) is connected to the discharge source of high-salt wastewater, and the other end of the pretreatment water pump (700) is connected to one end of the pretreatment device (800), and the other end of the pretreatment device (800) is connected to the concentration tower (200).

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