Flue gas desulfurization wastewater treatment system and method

Abstract

The invention discloses a flue gas desulfurization wastewater treatment system and method, comprising a wastewater pool, a pre-filter unit, a three-effect evaporation system, a condenser, a heat exchanger and a mud pump which are sequentially connected; wherein the wastewater pool stores wastewater, and a cleaning water delivery port is provided on one side of the wastewater pool, the pre-filter unit is provided on one side of the wastewater pool, a pumping pump is provided between the pre-filter unit and the wastewater pool, and the wastewater is pre-treated by the pre-filter unit; the three-effect evaporation system is located outside the pre-filter unit and is connected to the drain port of the pre-filter unit; a condenser is provided on one side of the three-effect evaporation system, and the condenser recovers concentrated wastewater in the three-effect evaporation system; the condenser is externally connected to a heat exchanger, and a mud pump is provided on one side of the heat exchanger. The invention can maintain the stability of the water quality treated at each stage in evaporation and concentration, ensure the final effluent quality, and meet strict emission standards or reuse requirements.

Description

Technical Field

[0001] The invention belongs to the technical field of desulfurization wastewater treatment, and specifically relates to a flue gas desulfurization wastewater treatment system and method. Background Art

[0002] The large amount of sulfur-containing flue gas generated by coal-fired power plants is mostly treated by wet desulfurization. The sulfur dioxide in the flue gas is removed by reacting with lime slurry to form calcium sulfate or calcium sulfite. The desulfurization wastewater produced by traditional processes has the characteristics of high salt content, high suspended matter content, high hardness, and strong corrosiveness, so it cannot be discharged directly; and the existing technology for treating desulfurization wastewater is mostly through flash concentration using reduced pressure heating to evaporate the water in the wastewater, thereby concentrating the waste liquid, reducing the volume of subsequent treatment, and reducing treatment costs. However, most flash evaporation equipment, such as the three-effect evaporation system, is prone to scaling of the heat exchanger surface during the evaporation process, affecting the heat transfer efficiency. At the same time, its processing capacity and flexibility cannot adapt to large-scale wastewater treatment or large changes in water quality; resulting in the treated wastewater being in different degrees of concentration, affecting the treatment effect;

[0003] Therefore, it is necessary to provide a flue gas desulfurization wastewater treatment system and method to solve the problems raised in the above background technology. Summary of the invention

[0004] To achieve the above-mentioned object, the present invention provides the following technical solutions: a flue gas desulfurization wastewater treatment system, comprising a wastewater pool, a pre-filter unit, a three-effect evaporation system, a condenser, a heat exchanger and a sludge pump which are sequentially connected; wherein the wastewater pool stores wastewater and has a cleaning water delivery port on one side thereof, the pre-filter unit is arranged on one side of the wastewater pool, a pumping pump is arranged between the pre-filter unit and the wastewater pool, and the wastewater is pre-treated by the pre-filter unit; the three-effect evaporation system is located outside the pre-filter unit and is connected to the drain port of the pre-filter unit;

[0005] A condenser is arranged on one side of the triple-effect evaporation system, and the condenser recovers concentrated wastewater in the triple-effect evaporation system; a heat exchanger is externally connected to the condenser, and a sludge pump is arranged on one side of the heat exchanger;

[0006] The three-effect evaporation system includes a plurality of evaporators arranged in a certain arrangement, and the evaporators are sequentially arranged as a first-effect evaporator, a second-effect evaporator and a third-effect evaporator based on the distribution position characteristics, and the evaporators are each composed of an adjustable heat exchange unit and a separator, and the wastewater enters the adjustable heat exchange unit for evaporation and concentration, and the concentrated wastewater flows into the separator for vapor-liquid separation;

[0007] The adjustable heat exchange unit includes a tube, and a plurality of heat exchange tube groups are distributed up and down inside the tube. A main delivery channel is vertically connected to the lower side of one side of the tube for delivering wastewater into the heat exchange tube group in the tube for evaporation and concentration, and a main discharge channel is vertically connected to the upper side of the other side of the tube. A steam inlet and a steam outlet are arranged on the side wall of the tube at each heat exchange tube group.

[0008] A flow control mechanism is provided between adjacent heat exchange tube groups, and the flow control mechanism is used to connect or close two heat exchange tube groups distributed up and down respectively, and the two sides of the flow control mechanism are respectively connected to a water supply branch pipe and a water discharge branch pipe;

[0009] The drainage branch pipe is connected with a side pipe, and the side pipe is connected to a density meter. The density meter detects the concentration of the wastewater evaporated and concentrated in each heat exchange tube group. The drainage branch pipe is connected to the separator in each evaporator through a plurality of section pipes.

[0010] Further, as a preference, each of the water supply branches delivers waste water to the adjacent upper heat exchange tube group through a flow control mechanism, and the drainage branch discharges waste water in the adjacent lower heat exchange tube group to the outside through a flow control mechanism.

[0011] Further, as a preference, a liquid supply seat and a liquid discharge seat are respectively provided at the upper and lower ends of the heat exchange tube group, and the flow control mechanism is distributed between adjacent liquid supply seats and liquid discharge seats.

[0012] Further, preferably, the flow control mechanism comprises:

[0013] A positioning ring is fixed on the inner wall of the tube, and a flow guide sleeve is rotatably connected to the positioning ring. The flow guide sleeve is composed of an upper connecting sleeve and a lower connecting sleeve distributed up and down, and the upper connecting sleeve and the lower connecting sleeve are fixed;

[0014] The inner channel is circumferentially distributed in the upper sleeve and the lower sleeve, and the liquid delivery seat and the liquid discharge seat are also provided with flow holes, and the flow holes are arranged one by one with the inner channel; a driving part is provided in the tube, and the driving part is connected and transmitted with the guide sleeve through the meshing action of gears, and the flow holes on the upper sleeve and the lower sleeve are connected or staggered with the inner channel during the rotation of the guide sleeve;

[0015] The central channel is arranged in the middle of the upper sleeve, a bypass channel 1 is radially arranged inside the lower sleeve, the bypass channel 1 is sealed and connected with the central channel, a connecting hole is opened on the side wall of the liquid drain seat, and the central channel is connected with the connecting hole;

[0016] The lower ring sleeve is fixed in the tube and located below the positioning ring. A liquid transfer bin 1 is provided inside the lower ring sleeve. The liquid transfer bin 1 is sealed and connected to the bypass channel 1. One end of the water supply branch is connected to the liquid transfer bin 1 and is connected to the bypass channel 1 through the liquid transfer bin 1.

[0017] Further, as a preference, a bypass channel 2 is radially arranged inside the lower connecting sleeve, and the bypass channel 2 is connected to the drainage branch pipe through the liquid transfer tank 2 arranged inside the lower ring sleeve. A straight channel is arranged in the middle of the lower connecting sleeve, and the upper end of the straight channel is connected to one end of the bypass channel 2, and the lower end of the straight channel is connected to the liquid delivery seat;

[0018] A sealing ring is provided inside the upper sleeve at the periphery of the central channel, and a side hole is opened on the sealing ring. The side hole is sealed and connected with the central channel, so that when the side hole is connected with the connecting hole correspondingly, the central channel is connected with the connecting hole.

[0019] Further, as a preference, when the flow holes on the upper connecting sleeve and the lower connecting sleeve in the guide sleeve are connected to the inner channel, the central channel in the upper connecting sleeve is staggered from the connecting hole. At this time, the wastewater in the total delivery channel enters the heat exchange tube group through the inner channels in each flow control mechanism in turn, and is discharged from the total discharge channel; when the flow holes on the upper connecting sleeve and the lower connecting sleeve in the guide sleeve are staggered from the inner channel, the central channel is connected to the connecting hole, and the straight channel is connected to the drainage branch pipe. At this time, the wastewater in each water delivery branch pipe passes through the heat exchange tube group accordingly and is discharged from the drainage branch pipe.

[0020] Further, as a preference, the heat exchange tube group is divided into two groups of different combined tubes, an isolation rib plate is provided inside the drain seat, the isolation rib plate divides the drain seat into two independent chambers, and the two groups of combined tubes are respectively connected to the independent chambers;

[0021] The connecting holes on the liquid drain seat are multiple and symmetrically distributed, and are connected to the independent chambers respectively.

[0022] Further, as a preference, two of the connecting holes on the drain seat are distributed in a straight line, so that the central channel can be connected to two independent chambers at the same time through the connecting holes.

[0023] Further, as a preferred embodiment, a method for treating flue gas desulfurization wastewater comprises the following steps:

[0024] S1. Wastewater transportation: the water inlet system consisting of a wastewater pool transports wastewater to a pre-filter unit through a pumping pump, wherein a sedimentation agent is added to the wastewater pool to initially deposit impurities in the wastewater; and the pre-filter unit physically filters the non-depositable impurities in the wastewater;

[0025] S2. Three-effect evaporation and concentration. The wastewater after preliminary treatment enters the three-effect evaporation system, where it is evaporated and concentrated. After the wastewater passes through the adjustable heat exchange unit in the first-effect evaporator for heat exchange and reaches evaporation and concentration, it enters the separator for vapor-liquid separation, and then is distributed through each water supply branch in the second-effect evaporator and sent to each heat exchange tube group inside it. Each heat exchange tube group distributed up and down performs heat exchange separately. The evaporated and concentrated wastewater flows through the drainage branch in the second-effect evaporator. At this time, the density meter detects the concentration of the evaporated and concentrated wastewater in each heat exchange tube group;

[0026] S3. Control the transportation, and transport the wastewater of the same concentration through the drainage pipe to the separator in the evaporator for vapor-liquid separation, so that the evaporated and concentrated wastewater can reach the uniform evaporation concentration standard before being discharged;

[0027] S4. Heat exchange and drainage: condense the wastewater discharged from the triple-effect evaporation system to fully precipitate the crystallized salt from the saturated wastewater. After entering the heat exchanger, the crystallized salt precipitates under the action of gravity. The crystallized salt and other solid impurities in the heat exchanger are transported outward through pipelines for solid forming treatment, and solid-liquid separation is achieved;

[0028] S5. The sludge pump pumps out the remaining liquid in the heat exchanger and passes it through an external clarification tank for subsequent treatment.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] The triple-effect evaporation system used for desulfurization wastewater treatment in the present invention can, on the one hand, perform triple-effect concentration as in a conventional series arrangement, and on the other hand, after the adjustable heat exchange unit performs heat exchange evaporation and concentration on the wastewater, the concentrated wastewater can enter the same separator for vapor-liquid separation according to the degree of evaporation and concentration, thus being able to adapt to different working conditions, improving the flexibility and efficiency of system processing, helping to maintain the stability of the treated water quality at each stage, ensuring the final effluent quality, and meeting strict emission standards or reuse requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic diagram of the flue gas desulfurization wastewater treatment process of the present invention.

[0032] Figure 2 It is a schematic diagram of the structure of the adjustable heat exchange unit in the present invention.

[0033] Figure 3 The structure of the heat exchange tube group and the flow control mechanism in the present invention is schematically shown. Figure 1 .

[0034] Figure 4 The structure of the heat exchange tube group and the flow control mechanism in the present invention is schematically shown. Figure 2 .

[0035] Figure 5 It is a schematic diagram of the structure of the independent chamber in the present invention.

[0036] Figure 6 It is a schematic diagram of the working process of the triple-effect evaporation system in the present invention.

[0037] In the figure: 1. Wastewater pool; 11. Pre-filter unit; 12. Condenser; 13. Heat exchanger; 14. Mud pump; 2. Three-effect evaporation system; 21. Evaporator; 22. Separator; 3. Adjustable heat exchange unit; 31. Tube; 32. Main delivery channel; 33. Main discharge channel; 34. Steam inlet; 35. Steam outlet; 36. Water supply branch; 37. Drainage branch; 38. Side pipe; 4. Heat exchange tube group; 41. Liquid delivery seat; 42, liquid discharge seat; 43, flow hole; 44, isolation rib plate; 45, independent chamber; 5, flow control mechanism; 51, positioning ring; 52, upper connecting sleeve; 53, lower connecting sleeve; 531, bypass channel 2; 532, straight channel; 54, inner channel; 55, center channel; 56, bypass channel 1; 57, connecting hole; 58, sealing ring; 59, side hole; 6, lower ring sleeve; 61, liquid transfer tank 1; 62, liquid transfer tank 2. DETAILED DESCRIPTION

[0038] See also Figure 1-Figure 6 In an embodiment of the present invention, a flue gas desulfurization wastewater treatment system includes a wastewater pool 1, a pre-filter unit 11, a three-effect evaporation system 2, a condenser 12, a heat exchanger 13 and a sludge pump 14 which are sequentially connected; wherein the wastewater pool 1 stores wastewater, and a cleaning water delivery port is provided on one side thereof, the pre-filter unit 11 is provided on one side of the wastewater pool, a pumping pump is provided between the pre-filter unit 11 and the wastewater pool 1, and the wastewater is pre-treated by the pre-filter unit 11; the three-effect evaporation system 2 is located outside the pre-filter unit, and is connected to the drain port of the pre-filter unit 11;

[0039] A condenser 12 is arranged on one side of the triple-effect evaporation system 2, and the condenser 12 recovers concentrated wastewater in the triple-effect evaporation system 2; the condenser 12 is externally connected to a heat exchanger 13, and a sludge pump 14 is arranged on one side of the heat exchanger 13; wherein, by condensing the saturated wastewater discharged from the evaporation system, the wastewater can be further concentrated and the soluble salt therein can be made supersaturated, thereby inducing the occurrence of a crystallization process, effectively separating water and salt, and laying the foundation for subsequent solid-liquid separation; the precipitated crystallized salt and other solid impurities will naturally settle under the action of gravity after entering the heat exchanger or other precipitation areas.

[0040] The three-effect evaporation system 2 includes a plurality of evaporators 21 arranged in a certain arrangement, and the evaporators 21 are sequentially a first-effect evaporator, a second-effect evaporator and a third-effect evaporator based on the distribution position characteristics. The evaporators 21 are each composed of an adjustable heat exchange unit 3 and a separator 22. The wastewater enters the adjustable heat exchange unit 3 for evaporation and concentration, and the concentrated wastewater flows into the separator 22 for vapor-liquid separation.

[0041] The adjustable heat exchange unit 3 includes a tube 31, in which a plurality of heat exchange tube groups 4 are distributed up and down. A main delivery channel 32 is vertically connected to the lower side of one side of the tube 31, which is used to deliver wastewater into the heat exchange tube group 4 in the tube 31 for evaporation and concentration, and a main discharge channel 33 is vertically connected to the upper side of the other side of the tube 31. A steam inlet 34 and a steam outlet 35 are provided on the side wall of the tube 31 at each heat exchange tube group 4; the main delivery channel is used to deliver wastewater into the tube, so that the wastewater can pass through each heat exchange tube group 4 in sequence and finally be discharged from the main discharge channel;

[0042] A flow control mechanism 5 is provided between adjacent heat exchange tube groups 4, and the flow control mechanism 5 is used to connect or close two upper and lower heat exchange tube groups 4, and the two sides of the flow control mechanism 5 are respectively connected to a water supply branch pipe 36 and a water discharge branch pipe 37;

[0043] The drainage branch pipe 37 is connected to a side pipe 38, and the side pipe 38 is externally connected to a density meter, and the density meter detects the concentration of the wastewater evaporated and concentrated in each heat exchange tube group 4. The drainage branch pipe 37 is externally connected to the separator 22 in each evaporator 21 through a plurality of section pipes; when the wastewater enters the three-effect evaporation system, the adjustable heat exchange unit in each evaporator 21 is connected to the heat exchange tube group 4 distributed up and down, and the wastewater passes through the first-effect evaporator, the second-effect evaporator and the third-effect evaporator in sequence, and the wastewater is efficiently concentrated and treated, and the concentrated wastewater enters the next process;

[0044] In this embodiment, each of the water supply branches transports wastewater to the adjacent upper heat exchange tube group through a flow control mechanism, and the drainage branch discharges the wastewater in the adjacent lower heat exchange tube group to the outside through a flow control mechanism, that is, a flow channel is formed between the water supply branch, the heat exchange tube group and the drainage branch.

[0045] In this embodiment, a liquid supply seat 41 and a liquid discharge seat 42 are respectively provided at the upper and lower ends of the heat exchange tube group 4 , and the flow control mechanism 5 is distributed between adjacent liquid supply seats 41 and liquid discharge seats 42 .

[0046] In this embodiment, the flow control mechanism 5 includes:

[0047] A positioning ring 51 is fixed on the inner wall of the tube 31. A guide sleeve 511 is rotatably connected to the positioning ring 51. The guide sleeve is composed of an upper connecting sleeve 52 and a lower connecting sleeve 53 which are distributed up and down. The upper connecting sleeve 52 and the lower connecting sleeve 53 are fixed.

[0048] The inner channel 54 is circumferentially distributed in the upper sleeve 52 and the lower sleeve 53. The liquid delivery seat 41 and the liquid discharge seat 42 are also provided with flow holes 43, and the flow holes 43 are arranged one by one with the inner channel 54. A driving part (not shown in the figure) is provided in the tube 31, and the driving part is connected and transmitted with the guide sleeve through gear meshing. The flow holes 43 on the upper sleeve 52 and the lower sleeve 53 are connected or staggered with the inner channel 54 during the rotation of the guide sleeve. The rotation angle of the guide sleeve is less than 90°.

[0049] The central channel 55 is arranged in the middle of the upper connecting sleeve 52. A bypass channel 1 56 is radially arranged inside the lower connecting sleeve 53. The bypass channel 1 56 is sealed and connected with the central channel 55. A connecting hole 57 is opened on the side wall of the liquid drain seat 42. The central channel 55 is connected with the connecting hole 57.

[0050] The lower ring sleeve 6 is fixed in the tube 31 and is located below the positioning ring 51. A liquid transfer bin 61 is provided inside the lower ring sleeve 6. The liquid transfer bin 61 is sealed and connected to the bypass channel 56. One end of the water supply branch 36 is connected to the liquid transfer bin 61 and is connected to the bypass channel 56 through the liquid transfer bin 61.

[0051] In this embodiment, a bypass channel 2 531 is radially arranged inside the lower connecting sleeve 53, and the bypass channel 2 531 is connected to the drainage branch pipe 37 through the liquid transfer tank 2 62 arranged inside the lower ring sleeve. A straight channel 532 is arranged in the middle of the lower connecting sleeve 53, and the upper end of the straight channel 532 is connected to one end of the bypass channel 2 531, and the lower end of the straight channel 532 is connected to the liquid delivery seat 41; so that the wastewater in the heat exchange tube group can flow into the bypass channel 2 through the straight channel 532 after entering the liquid delivery seat, and finally enter the drainage branch pipe through the bypass channel 2 for discharge;

[0052] A sealing ring 58 is provided in the upper sleeve 52 at the periphery of the central channel 55 , and a side hole 59 is opened on the sealing ring 58 . The side hole 59 is sealed and connected to the central channel 55 , so that when the side hole 59 is connected to the connecting hole 57 correspondingly, the central channel 55 is connected to the connecting hole 57 .

[0053] In this embodiment, when the flow holes 43 on the upper and lower sleeves 52 and 53 in the guide sleeve are connected to the inner channel 54, the central channel 55 in the upper sleeve 52 is staggered with the connecting hole 57. At this time, the wastewater in the total delivery channel 32 enters the heat exchange tube group 4 through the inner channels 54 in each flow control mechanism 5 in turn, and is discharged from the total discharge channel 33; when the flow holes 43 on the upper and lower sleeves 52 and 53 in the guide sleeve are staggered with the inner channel 54, the central channel 55 and the connecting hole 57 are staggered. 7 are connected, and the straight channel 532 is connected with the drainage branch pipe 37. At this time, the wastewater in each water supply branch 36 passes through the heat exchange tube group 4 accordingly and is discharged from the drainage branch pipe 37, so that the wastewater can pass through each heat exchange tube group 4 in sequence to form a flow route with the main delivery channel as the wastewater inlet and the main drainage channel as the wastewater outlet; on the other hand, the wastewater is divided and passes through the heat exchange tube group respectively, with each water supply branch as the wastewater inlet and each drainage branch pipe as the wastewater outlet, which has high flexibility.

[0054] In this embodiment, the heat exchange tube group 4 is divided into two groups of different combined tubes. An isolation rib plate 44 is provided inside the drain seat 42. The isolation rib plate 44 divides the drain seat 42 into two independent chambers 45. The two groups of combined tubes are respectively connected to the independent chambers 45. The two groups of heat exchange tubes can serve as backup or work together. Once one group fails or needs maintenance, the other group can continue to work to ensure the continuous and stable operation of the evaporation system. At the same time, for wastewater with different concentrations or flows, the working states of the two groups of heat exchange tubes (such as the number of openings, heat exchange intensity, etc.) can be adjusted to flexibly adapt to changes in treatment requirements, thereby improving the flexibility and adaptability of the overall treatment system.

[0055] The connecting holes 57 on the drain seat 42 are multiple and symmetrically distributed, and are connected to the independent chambers 45 respectively.

[0056] In this embodiment, two of the connecting holes 57 on the drain seat 42 are distributed in a straight line, so that the central channel 55 can be connected to the two independent chambers 45 at the same time through the connecting holes 57 .

[0057] In another embodiment, the wastewater preferentially enters the adjustable heat exchange unit in the first-effect evaporator through each water supply branch 36. At this time, the wastewater is heat exchanged by each heat exchange tube group 4 in the tube 31 and enters the separator 22 for vapor-liquid separation after evaporation and concentration. Then, the wastewater is distributed through each water supply branch 36 in the second-effect evaporator and sent to each heat exchange tube group 4 therein. Each heat exchange tube group 4 distributed up and down performs heat exchange separately. The evaporated and concentrated wastewater flows through the drainage branch 37 in the second-effect evaporator. At this time, the density meter detects the concentration of the evaporated and concentrated wastewater in each heat exchange tube group 4, and transports it to the separator in the first-effect evaporator, the separator in the second-effect evaporator, or the separator in the third-effect evaporator through the drainage branch 37 according to the detected concentration.

[0058] The liquid separated by the separator in the first-effect evaporator enters the adjustable heat exchange unit in the second-effect evaporator for evaporation and concentration; the liquid separated by the separator in the second-effect evaporator enters the adjustable heat exchange unit in the third-effect evaporator for evaporation and concentration; the liquid separated by the separator in the second-effect evaporator is directly discharged;

[0059] In another embodiment, the wastewater preferentially enters the adjustable heat exchange unit in the first-effect evaporator through each water supply branch 36. At this time, the heat exchange and evaporation are performed by each heat exchange tube group 4 in the tube 31. After evaporation and concentration, the wastewater is sequentially detected by the density meter and then, based on its concentration degree, is transported to the separator in the first-effect evaporator, the separator in the second-effect evaporator, or the separator in the third-effect evaporator through the drainage branch 37.

[0060] The liquid separated by the separator in the first-effect evaporator enters the adjustable heat exchange unit in the second-effect evaporator for evaporation and concentration; the liquid separated by the separator in the second-effect evaporator enters the adjustable heat exchange unit in the third-effect evaporator for evaporation and concentration; the liquid separated by the separator in the second-effect evaporator is directly discharged;

[0061] Such a setting can not only optimize the energy utilization of the evaporation process, avoid excessive or insufficient evaporation, and improve the treatment efficiency and resource utilization, but also dynamically adjust the wastewater flow direction according to the actual treatment needs and balance the workload of each evaporator; especially in the triple-effect evaporation system, the separators are allocated to different evaporators according to the degree of concentration, making the vapor-liquid separation process more efficient, reducing the treatment time, and increasing the treatment volume per unit time. At the same time, the targeted separation design helps to maintain the stability of the treated water quality at each stage, ensure the final effluent quality, and meet strict emission standards or reuse requirements.

[0062] A method for treating flue gas desulfurization wastewater comprises the following steps:

[0063] S1. Wastewater transportation, the water inlet system consisting of the wastewater pool 1 transports the wastewater to the pre-filter unit 11 through a pumping pump, wherein a sedimentation agent is added to the wastewater pool 1 to preliminarily precipitate impurities in the wastewater; and the pre-filter unit 11 physically filters the non-precipitable impurities in the wastewater;

[0064] S2. Three-effect evaporation and concentration. The wastewater after preliminary treatment enters the three-effect evaporation system 2, and is evaporated and concentrated by the three-effect evaporation system 2. After the wastewater undergoes heat exchange in the adjustable heat exchange unit 3 in the first-effect evaporator and reaches evaporation and concentration, it enters the separator 22 for vapor-liquid separation, and then is distributed through each water supply branch 36 in the second-effect evaporator and sent to each heat exchange tube group 4 inside it. Each heat exchange tube group 4 distributed up and down performs heat exchange separately, and the evaporated and concentrated wastewater flows through the drainage branch 37 in the second-effect evaporator. At this time, the density meter detects the concentration of the evaporated and concentrated wastewater in each heat exchange tube group 4;

[0065] S3. Control the delivery, and deliver the wastewater of the same concentration concentration to the separator 22 in the evaporator 21 through the drainage pipe 37 for vapor-liquid separation, so that the evaporated and concentrated wastewater can reach a uniform evaporation concentration standard before being discharged;

[0066] S4. Heat exchange and drainage, condensing the wastewater discharged from the triple-effect evaporation system 2, so that the saturated wastewater is fully precipitated with crystallized salt, so that the crystallized salt is precipitated under the action of gravity after entering the heat exchanger 13, and the crystallized salt and other solid impurities in the heat exchanger 13 are transported outward through a pipeline for solid forming treatment, and solid-liquid separation is achieved;

[0067] S5. The sludge pump 14 pumps out the remaining liquid in the heat exchanger and passes it through an external clarification tank for subsequent treatment.

[0068] What is described above is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A flue gas desulfurization wastewater treatment system, characterized in that: The invention comprises a wastewater tank (1), a pre-filter unit (11), a three-effect evaporation system (2), a condenser (12), a heat exchanger (13) and a sludge pump (14) which are arranged in sequence; wherein the wastewater tank (1) stores wastewater and has a cleaning water delivery port on one side thereof; the pre-filter unit (11) is arranged on one side of the wastewater tank (1); a pumping pump is arranged between the pre-filter unit (11) and the wastewater tank (1); and the wastewater passes through the pre-filter unit (11) for primary pretreatment; and the three-effect evaporation system (2) is located outside the pre-filter unit (11) and is connected to the drainage port of the pre-filter unit (11); A condenser (12) is disposed on one side of the triple-effect evaporation system (2), and the condenser (12) recovers concentrated wastewater in the triple-effect evaporation system (2); the condenser (12) is externally connected to a heat exchanger (13), and a sludge pump (14) is disposed on one side of the heat exchanger (13); The three-effect evaporation system (2) comprises a plurality of evaporators (21) arranged in a certain arrangement, and the evaporators (21) are respectively a first-effect evaporator, a second-effect evaporator and a third-effect evaporator based on the distribution position characteristics, and each of the evaporators (21) is composed of an adjustable heat exchange unit (3) and a separator (22), and wastewater enters the adjustable heat exchange unit (3) for evaporation and concentration, and the concentrated wastewater flows into the separator (22) for vapor-liquid separation; The adjustable heat exchange unit (3) comprises a tube (31) in which a plurality of heat exchange tube groups (4) are distributed vertically. A main delivery channel (32) is vertically connected to the lower side of one side of the tube (31) for delivering wastewater into the heat exchange tube group (4) in the tube (31) for evaporation and concentration. A main discharge channel (33) is vertically connected to the upper side of the other side of the tube (31). A steam inlet (34) and a steam outlet (35) are provided on the side wall of the tube (31) at each heat exchange tube group (4). A flow control mechanism (5) is provided between adjacent heat exchange tube groups (4), the flow control mechanism (5) being used to connect or close two heat exchange tube groups (4) distributed above and below, and the two sides of the flow control mechanism (5) are respectively connected to a water supply branch pipe (36) and a water discharge branch pipe (37); The drainage branch pipe (37) is connected to a side pipe (38), and the side pipe (38) is externally connected to a density meter, and the density meter detects the concentration of the wastewater after evaporation and concentration in each heat exchange tube group (4). The drainage branch pipe (37) is externally connected to the separator (22) in each evaporator (21) through a plurality of section pipes. A liquid supply seat (41) and a liquid discharge seat (42) are respectively provided at the upper and lower ends of the heat exchange tube group (4), and the flow control mechanism (5) is distributed between adjacent liquid supply seats (41) and liquid discharge seats (42); The flow control mechanism (5) comprises: A positioning ring (51) is fixed on the inner wall of the tube (31), and a flow guide sleeve is rotatably connected to the positioning ring (51), wherein the flow guide sleeve is composed of an upper connecting sleeve (52) and a lower connecting sleeve (53) which are arranged vertically, and the upper connecting sleeve (52) and the lower connecting sleeve (53) are fixed to each other; The inner channel (54) is circumferentially distributed in the upper connecting sleeve (52) and the lower connecting sleeve (53); the liquid delivery seat (41) and the liquid discharge seat (42) are also provided with flow holes (43); the flow holes (43) and the inner channel (54) are arranged in a one-to-one correspondence; a driving unit is provided in the tube (31); the driving unit is connected to the guide sleeve for transmission through gear meshing; the flow holes (43) on the upper connecting sleeve (52) and the lower connecting sleeve (53) are connected to or staggered with the inner channel (54) during the rotation of the guide sleeve; A central channel (55) is arranged in the middle of the upper connecting sleeve (52); a side channel (56) is radially arranged inside the lower connecting sleeve (53); the side channel (56) is sealed and connected to the central channel (55); a connecting hole (57) is opened on the side wall of the liquid discharge seat (42); and the central channel (55) is connected to the connecting hole (57); A lower ring sleeve (6) is fixed in the tube (31) and is located below the positioning ring (51). A liquid transfer bin (61) is provided inside the lower ring sleeve (6). The liquid transfer bin (61) is sealed and communicated with the bypass channel (56). One end of the water supply branch (36) is communicated with the liquid transfer bin (61) and is communicated with the bypass channel (56) through the liquid transfer bin (61). A second bypass channel (531) is radially arranged inside the lower connecting sleeve (53), and the second bypass channel (531) is connected to the drainage branch pipe (37) through a second liquid transfer tank (62) arranged inside the lower annular sleeve (6). A straight channel (532) is arranged in the middle of the lower connecting sleeve (53), and the upper end of the straight channel (532) is connected to one end of the second bypass channel (531), and the lower end of the straight channel (532) is connected to the liquid delivery seat (41); A sealing ring (58) is provided in the upper connecting sleeve (52) at the periphery of the central channel (55), and a side hole (59) is provided on the sealing ring (58). The side hole (59) is sealed and connected to the central channel (55), so that when the side hole (59) is correspondingly connected to the connecting hole (57), the central channel (55) is connected to the connecting hole (57); When the flow holes (43) on the upper connecting sleeve (52) and the lower connecting sleeve (53) in the guide sleeve are connected to the inner channel (54), the central channel (55) in the upper connecting sleeve (52) and the connecting hole (57) are staggered, and the wastewater in the main delivery channel (32) enters the heat exchange tube group (4) through the inner channels (54) in each flow control mechanism (5) in turn, and is discharged from the main discharge channel (33); when the flow holes (43) on the upper connecting sleeve (52) and the lower connecting sleeve (53) in the guide sleeve and the inner channel (54) are staggered, the central channel (55) and the connecting hole (57) are connected, and the straight channel (532) and the drainage branch pipe (37) are connected, and the wastewater in each water delivery branch pipe (36) passes through the heat exchange tube group (4) and is discharged from the drainage branch pipe (37).

2. A flue gas desulfurization wastewater treatment system according to claim 1, characterized in that: Each water supply branch pipe (36) delivers waste water to the adjacent upper heat exchange tube group (4) through the flow control mechanism (5), while the drainage branch pipe (37) discharges waste water in the adjacent lower heat exchange tube group (4) to the outside through the flow control mechanism (5).

3. A flue gas desulfurization wastewater treatment system according to claim 1, characterized in that: The heat exchange tube group (4) is divided into two groups of different combined tubes. An isolation rib plate (44) is provided inside the liquid drain seat (42). The isolation rib plate (44) divides the liquid drain seat (42) into two independent chambers (45). The two groups of combined tubes are respectively connected to the independent chambers (45). The connecting holes (57) on the liquid drain seat (42) are arranged in a plurality and are symmetrically distributed, and are respectively connected to the independent chambers (45).

4. A flue gas desulfurization wastewater treatment system according to claim 3, characterized in that: Two of the connecting holes (57) on the liquid drain seat (42) are distributed in a straight line, so that the central channel (55) can be connected to the two independent chambers (45) through the connecting holes (57) at the same time.

5. A method for treating flue gas desulfurization wastewater, which adopts a flue gas desulfurization wastewater treatment system according to any one of claims 1 to 4, characterized in that: It includes the following steps: S1. Wastewater transport, the water inlet system consisting of the wastewater pool (1) transports the wastewater to the pre-filter unit (11) through a pumping pump, wherein a sedimentation agent is added to the wastewater pool (1) to cause the impurities in the wastewater to be initially deposited; and the pre-filter unit (11) physically filters the non-depositable impurities in the wastewater; S2. Three-effect evaporation and concentration, the wastewater after preliminary treatment enters the three-effect evaporation system (2), and is evaporated and concentrated by the three-effect evaporation system (2); wherein the wastewater is heat exchanged by the adjustable heat exchange unit (3) in the first-effect evaporator and evaporated and concentrated, and then enters the separator (22) for vapor-liquid separation, and then distributed through each water supply branch (36) in the second-effect evaporator to be diverted and sent to each heat exchange tube group (4) inside the second-effect evaporator, and each heat exchange tube group (4) distributed up and down performs heat exchange separately, and the evaporated and concentrated wastewater flows through the drainage branch (37) in the second-effect evaporator, and at this time, the density meter is used to detect the concentration of the evaporated and concentrated wastewater in each heat exchange tube group (4); S3. Controlling the transportation, and transporting the wastewater of the same concentration through the drainage branch pipe (37) to the separator (22) in the evaporator (21) for vapor-liquid separation, so that the evaporated and concentrated wastewater can reach a uniform evaporation concentration standard before being discharged; S4. heat exchange and drainage, condensing the wastewater discharged from the three-effect evaporation system (2) so that the saturated wastewater is fully precipitated with crystallized salt, so that the crystallized salt is precipitated under the action of gravity after entering the heat exchanger (13), and the crystallized salt and other solid impurities in the heat exchanger (13) are transported outward through a pipeline for solid forming treatment, thereby achieving solid-liquid separation; S5. The sludge pump (14) pumps out the remaining liquid in the heat exchanger (13) and passes it through an external clarification tank for subsequent treatment.

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