Desulfurization wastewater treatment system

Abstract

The invention relates to the technical field of desulfurization wastewater treatment, in particular to a desulfurization wastewater treatment system which comprises a gypsum cyclone used for performing solid-liquid separation treatment on desulfurization wastewater from a gypsum slurry buffer tank and then conveying upper cyclone overflow into a gypsum overflow slurry tank; the gypsum overflow slurry tank is used for conveying the rotational flow overflow into the accident slurry tank when the chloride ion concentration value in the rotational flow overflow is greater than the set concentration threshold value of the absorption tower; the accident slurry tank is used for carrying out precipitation treatment on rotational flow overflow from the gypsum overflow slurry tank and then conveying clear liquid at the upper part of the accident slurry tank into the wastewater concentration tower; and the wastewater concentration tower is used for performing concentration reduction treatment on the clear liquid from the accident slurry box, and conveying the concentrated slurry to the drying system for drying treatment when the chloride ion concentration value of the slurry in the wastewater concentration tower reaches a concentration threshold value required by the drying system. By applying the system, the desulfurization wastewater treatment efficiency can be effectively improved.

Description

Technical Field

[0001] The invention relates to the technical field of desulfurization wastewater treatment, and in particular to a desulfurization wastewater treatment system. Background Art

[0002] The purpose of the external discharge of wastewater from thermal power generation wet desulfurization is, firstly, to control the concentration of halogen elements in the slurry, reduce equipment corrosion, and improve the quality of gypsum; secondly, to discharge acid insoluble matter, suspended matter, magnesium salts, etc. in the slurry, control the slurry quality, and ensure the desulfurization efficiency. Desulfurization wastewater has the characteristics of high hardness, high salt content, high turbidity, and strong corrosiveness. In addition, it also carries a small amount of heavy metals, fluorides and other hazardous substances. Due to the bad nature of desulfurization wastewater, it is difficult to consume and utilize in the plant, and it has become the most difficult wastewater to treat in power plants.

[0003] In the prior art, the chemical precipitation method is commonly used for the treatment of desulfurization wastewater, which mainly includes four steps: wastewater neutralization, heavy metal precipitation, coagulation and flocculation, and concentration / clarification. Specifically, wastewater neutralization is to adjust the pH value of desulfurization wastewater by alkaline neutralizers such as lime, limestone, caustic soda and sodium carbonate to achieve precipitation; heavy metal precipitation is to remove heavy metal ions and alkaline earth metals in wastewater by further using heavy metal sedimentation agents such as lime and sodium sulfide; coagulation and flocculation is to further add flocculants to make many small and dispersed particles and colloidal substances in desulfurization wastewater coagulate into large particles and precipitate; concentration / clarification is that the flocculated wastewater overflows from the reaction tank into the clarification / concentration tank equipped with an agitator, and the flocculants are deposited at the bottom and concentrated into sludge by gravity, and the upper part is clean water. Although the chemical precipitation method based on the above four steps can achieve the treatment of desulfurization wastewater, it has the following defects: 1. The treatment method of multi-stage sedimentation tank + chemical agent results in low treatment efficiency and high cost for desulfurization wastewater; 2. Since each level of sedimentation tank will produce sludge, an independent sludge treatment device needs to be installed at each level, resulting in high investment and operating costs.

[0004] Therefore, there is an urgent need for a desulfurization wastewater treatment system to solve the above problems. Summary of the invention

[0005] The purpose of the present invention is to solve the problems of low treatment efficiency and high cost in the treatment of desulfurization wastewater in the prior art, and to provide a desulfurization wastewater treatment system.

[0006] In order to achieve the above object, the present invention provides a desulfurization wastewater treatment system, which comprises: Gypsum slurry buffer tank, used to buffer and store desulfurization wastewater from the absorption tower; The gypsum cyclone is used to perform solid-liquid separation on the desulfurization wastewater from the gypsum slurry buffer tank, and then transport the bottom cyclone thick slurry to the belt conveyor, and the upper cyclone overflow is transported to the gypsum overflow slurry tank; A gypsum overflow slurry tank is used to monitor the chloride ion concentration value in the cyclone overflow from the gypsum cyclone, and when the chloride ion concentration value in the cyclone overflow is greater than the set concentration threshold of the absorption tower, the cyclone overflow is transported to the accident slurry tank, and when the chloride ion concentration value in the cyclone overflow is less than the set concentration threshold of the absorption tower, the cyclone overflow is transported to the absorption tower; An accident slurry tank is used to carry out sedimentation treatment on the cyclone overflow from the gypsum overflow slurry tank, and then transport the upper clear liquid to the wastewater concentration tower, and the lower sedimentation concentrated slurry is transported to the gypsum slurry buffer tank; The wastewater concentration tower is used to concentrate and reduce the clear liquid from the accident slurry tank, and when the chloride ion concentration value of the slurry in the wastewater concentration tower reaches the concentration threshold value required by the drying system, the concentrated slurry is transported to the drying system for drying treatment.

[0007] Preferably, the upper part of the wastewater concentrating tower is provided with a water distributor for introducing the clear liquid into the accident slurry tank and a heat source air pipe outlet section of the folded pipe arranged directly below the water distributor, and the upper surface of the heat source air pipe outlet section is provided with a plurality of air outlet holes, and the lower surface is provided with a plurality of liquid drainage holes.

[0008] Preferably, the wastewater concentration tower also includes a circulating spraying device, which includes a sprayer arranged between the water distributor and the heat source air pipe outlet section and a circulating pump for circulating the slurry in the wastewater concentration tower to the sprayer for spraying.

[0009] Preferably, the connection angle between the folded pipe section of the folded pipe and its heat source air pipe outlet section is 100-150°.

[0010] Preferably, the smoke inlet of the folded pipe is connected to the smoke inlet of the desulfurization absorption tower through a pipeline, and the smoke outlet at the top of the wastewater concentration tower is connected to the smoke return outlet of the desulfurization absorption tower inlet flue.

[0011] Preferably, a demister is also provided directly above the water distributor.

[0012] Preferably, it also includes a pH value adjusting device, which includes an alkali metering tank, an alkali metering pump and a pH measuring module arranged inside the wastewater concentrating tower, and the alkali metering pump is used to measure a corresponding amount of alkaline solution from the alkali metering tank according to the pH value of the slurry measured by the pH measuring module and transport it to the wastewater concentrating tower.

[0013] Preferably, the desulfurization wastewater in the gypsum slurry buffer tank is delivered to the gypsum cyclone through a buffer delivery pump, and the buffer delivery pump is driven by a variable frequency motor to adjust the inlet pressure of the gypsum cyclone in real time according to the unit load and / or gypsum quality.

[0014] Preferably, a wastewater transfer tank is further provided between the accident slurry tank and the wastewater concentrating tower, and the upper clear liquid of the accident slurry tank is first transported to the wastewater transfer tank, and then transported to the wastewater concentrating tower via the wastewater transfer tank.

[0015] Preferably, the upper side of the accident slurry tank is provided with a plurality of overflow ports from top to bottom.

[0016] According to the above technical scheme, based on the desulfurization wastewater treatment system, by setting a gypsum cyclone for solid-liquid separation treatment of the desulfurization wastewater from the gypsum slurry buffer tank, not only can the treatment of the desulfurization wastewater be achieved but also the crystallization quality of the gypsum can be improved. By setting a gypsum overflow slurry tank, when the chloride ion content of the cyclone overflow in the gypsum overflow slurry tank is low, the cyclone overflow can be returned to the absorption tower to continue to participate in the desulfurization reaction, thereby ensuring the desulfurization wastewater treatment efficiency while also improving the utilization rate of the slurry and saving the amount of limestone slurry; and by setting an accident slurry tank and transporting the lower precipitate to the gypsum slurry buffer tank, not only the treatment effect of the desulfurization wastewater and the crystallization quality of the gypsum can be improved, but also there is no need to set up a separate sludge treatment device; and by setting a wastewater concentration tower, not only can the concentration and reduction of the desulfurization wastewater be achieved based on the effective utilization of the flue gas waste heat of the desulfurization system, but also zero discharge of the desulfurization wastewater can be achieved based on the cooperation with the drying system. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a structural schematic diagram of the desulfurization wastewater treatment system.

[0018] Description of Reference Numerals 1. Gypsum slurry buffer tank; 11. Buffer delivery pump; 2. Gypsum cyclone; 3. Gypsum overflow slurry tank; 31. Slurry return pump; 32. Slurry delivery pump; 4. Accident slurry tank; 41. Sedimentation thick slurry delivery pump; 5. Wastewater transfer tank; 51. Wastewater transfer pump; 61. Alkali metering tank; 62. Alkali metering pump; 63. pH measurement module; 7. Wastewater concentration tower; 71. Bend pipe; 711. Heat source gas pipe outlet section; 72. Sprinkler; 73. Water distributor; 74. Circulation pump; 75. Wastewater delivery pump; 76. Demister. DETAILED DESCRIPTION

[0019] The specific implementation of the embodiment of the present invention is described in detail below. It should be understood that the specific implementation described here is only used to illustrate and explain the embodiment of the present invention, and is not used to limit the embodiment of the present invention.

[0020] The present invention provides a desulfurization wastewater treatment system, such as Figure 1 As shown, the desulfurization wastewater treatment system includes: A gypsum slurry buffer tank 1, used for buffering and storing desulfurization wastewater from the absorption tower; The gypsum cyclone 2 is used to perform solid-liquid separation on the desulfurization wastewater from the gypsum slurry buffer tank 1, and then transport the bottom cyclone concentrated slurry to the belt conveyor, and the upper cyclone overflow is transported to the gypsum overflow slurry tank 3; The gypsum overflow slurry tank 3 is used to monitor the chloride ion concentration value in the cyclone overflow from the gypsum cyclone 2, and when the chloride ion concentration value in the cyclone overflow is greater than the set concentration threshold of the absorption tower, the cyclone overflow is transported to the accident slurry tank 4, and when the chloride ion concentration value in the cyclone overflow is less than the set concentration threshold of the absorption tower, the cyclone overflow is transported to the absorption tower; The accident slurry tank 4 is used to carry out sedimentation treatment on the cyclone overflow from the gypsum overflow slurry tank 3, and then transport the upper clear liquid to the wastewater concentration tower 7, and the lower sedimentation concentrated slurry to the gypsum slurry buffer tank 1; The wastewater concentration tower 7 is used to concentrate and reduce the clear liquid from the accident slurry tank 4, and when the chloride ion concentration value of the slurry in the wastewater concentration tower 7 reaches the concentration threshold value required by the drying system, the concentrated slurry is transported to the drying system for drying treatment.

[0021] Wherein, the gypsum overflow slurry tank 3 and the wastewater concentration tower 7 are both provided with chloride ion monitoring instruments for measuring the chloride ion concentration of the desulfurization wastewater, and the concentration threshold required by the drying system is greater than the set concentration threshold of the absorption tower.

[0022] According to the above technical scheme, based on the desulfurization wastewater treatment system, by setting a gypsum cyclone for solid-liquid separation treatment of the desulfurization wastewater from the gypsum slurry buffer tank, not only can the treatment of the desulfurization wastewater be achieved but also the crystallization quality of the gypsum can be improved. By setting a gypsum overflow slurry tank, when the chloride ion content of the cyclone overflow in the gypsum overflow slurry tank is low, the cyclone overflow can be returned to the absorption tower to continue to participate in the desulfurization reaction, thereby ensuring the desulfurization wastewater treatment efficiency while also improving the utilization rate of the slurry and saving the amount of limestone slurry; and by setting an accident slurry tank and transporting the lower precipitate to the gypsum slurry buffer tank, not only the treatment effect of the desulfurization wastewater and the crystallization quality of the gypsum can be improved, but also there is no need to set up a separate sludge treatment device; and by setting a wastewater concentration tower, not only can the concentration and reduction of the desulfurization wastewater be achieved based on the effective utilization of the flue gas waste heat of the desulfurization system, but also zero discharge of the desulfurization wastewater can be achieved based on the cooperation with the drying system.

[0023] In the desulfurization wastewater treatment system of the present invention, preferably, Figure 1 As shown, the upper part of the wastewater concentration tower 7 is provided with a water distributor 73 for introducing the clear liquid in the accident slurry tank 4 and a heat source air pipe outlet section 711 of the folded pipe 71 arranged directly below the water distributor 73. The upper surface of the heat source air pipe outlet section 71 is provided with a plurality of air outlets, and the lower surface is provided with a plurality of drainage holes. By providing the water distributor 73 with one inlet and multiple outlets, when introducing the clear liquid, the clear liquid can be uniformly introduced into the wastewater concentration tower 7, and countercurrent heat and mass exchange is performed with the heat source flue gas guided out from the plurality of air outlets of the heat source air pipe outlet section 711, so that the water in the wastewater is continuously evaporated, thereby achieving the concentration and reduction of the wastewater; when introducing the flushing water, the sprinkler 72 and the related pipelines can be cleaned to avoid pipeline blockage when left for a long time. A plurality of air outlet holes are provided on the upper surface of the heat source air pipe opening section 711, and a plurality of liquid discharge holes are provided on the lower surface, and the number of the liquid discharge holes is less than the number of the air outlet holes. Figure 1 As shown, the drainage holes are provided at both ends and the middle, respectively, to ensure that the heat source flue gas can be discharged through the gas outlet holes for sufficient countercurrent heat and mass exchange with the clear liquid, while avoiding the accumulation of liquid in the heat source gas pipe outlet section 711. Preferably, the connection angle between the folded pipe section of the folded pipe 71 and its heat source gas pipe outlet section 711 is 100-150°, preferably 110-130°, and most preferably 120°, to ensure the normal introduction of the heat source flue gas, while further avoiding the accumulation of liquid from entering the heat source flue gas pipeline and affecting the introduction of the heat source flue gas.

[0024] Further preferably, Figure 1As shown, the wastewater concentration tower 7 also includes a circulating spraying device, which includes a sprayer 72 arranged between the water distributor 73 and the heat source air pipe outlet section 711 and a circulating pump 74 for circulating the slurry in the wastewater concentration tower 7 to the sprayer 72 for spraying, thereby further improving the heat exchange efficiency of the countercurrent heat and mass exchange between the slurry and the heat source flue gas based on the synergistic effect with the water distributor 73, thereby accelerating the evaporation efficiency of the water in the wastewater.

[0025] In the desulfurization wastewater treatment system described in the present invention, preferably, the smoke inlet of the folded pipe 71 is connected with the smoke inlet port of the inlet flue of the desulfurization absorption tower through a pipeline, and the smoke outlet at the top of the wastewater concentration tower 7 is connected with the smoke return port of the inlet flue of the desulfurization absorption tower, so that after the flue gas drawn out from the inlet flue of the desulfurization absorption tower is utilized for waste heat, it is returned to the inlet flue of the desulfurization absorption tower again, so as to avoid affecting the stability of the desulfurization absorption tower.

[0026] Further preferably, a demister 76 is provided directly above the water distributor 73 to further intercept the liquid component in the flue gas returning to the inlet flue of the desulfurization absorption tower, thereby avoiding the high liquid content in the flue gas returning to the inlet flue of the desulfurization absorption tower affecting the desulfurization performance of the desulfurization absorption tower.

[0027] In the desulfurization wastewater treatment system described in the present invention, preferably, it also includes a pH value adjusting device, which includes an alkali metering box 61, an alkali metering pump 62 and a pH measuring module 63 arranged inside the wastewater concentrating tower 7. The alkali metering pump 62 is used to measure a corresponding amount of alkaline solution from the alkali metering box 61 according to the pH value of the slurry measured by the pH measuring module 63 and transport it to the wastewater concentrating tower 7, so that the pH value of the slurry inside the wastewater concentrating tower 7 is stabilized at 7-9, thereby avoiding a high pH value of the slurry after concentration, which may cause corrosion to the wastewater concentrating tower 7 and the subsequent drying system.

[0028] In the desulfurization wastewater treatment system of the present invention, preferably, Figure 1 As shown, the desulfurization wastewater in the gypsum slurry buffer box 1 is transported to the gypsum cyclone through a buffer delivery pump 11, and the buffer delivery pump 11 is driven by a variable frequency motor, so that the inlet pressure of the gypsum cyclone 2 can be adjusted in real time according to the unit load and gypsum quality, thereby improving the slurry concentration and crystallization effect.

[0029] In the desulfurization wastewater treatment system of the present invention, preferably, Figure 1As shown, a wastewater transfer tank 5 is also provided between the accident slurry tank 4 and the wastewater concentration tower 7, and the upper clear liquid of the accident slurry tank 4 is first transported to the wastewater transfer tank 5, and then transported to the wastewater concentration tower 7 via the wastewater transfer tank 5. Further preferably, the upper side of the accident slurry tank 4 is provided with a plurality of overflow ports from top to bottom. In practical application, the overflow ports at the corresponding height of the upper side of the accident slurry tank 4 can be opened according to actual needs, so that the upper clear liquid flows into the wastewater transfer tank 5, and further when the clear liquid in the wastewater transfer tank 5 reaches a set amount, the clear liquid is introduced into the wastewater concentration tower 7 at a set pump speed through the wastewater transfer pump 51, so that the concentration and reduction process of the desulfurized wastewater can be carried out continuously and stably, thereby improving the concentration efficiency of the desulfurized wastewater and the utilization efficiency of the heat source flue gas, and avoiding the waste heat of the heat source flue gas caused by the intermittent introduction of the clear liquid. The sedimentation time of the accident slurry tank 4 for the cyclone overflow is preferably 8-10 hours to ensure the sedimentation effect and avoid the influence of more solid phase substances in the clear liquid on the subsequent concentration and drying process.

[0030] The present invention will be described in detail below through examples, but the protection scope of the present invention is not limited thereto.

[0031] Example 1 Use Figure 1 The desulfurization wastewater treatment system shown is used to treat desulfurization wastewater. Specifically, the desulfurization wastewater treatment system includes: A gypsum slurry buffer tank 1, used for buffering and storing desulfurization wastewater from the absorption tower; The gypsum cyclone 2 is used to perform solid-liquid separation on the desulfurization wastewater from the gypsum slurry buffer tank 1, and then transport the bottom cyclone concentrated slurry to the belt conveyor, and the upper cyclone overflow is transported to the gypsum overflow slurry tank 3; The gypsum overflow slurry tank 3 is used to monitor the chloride ion concentration value in the cyclone overflow from the gypsum cyclone 2, and when the chloride ion concentration value in the cyclone overflow is greater than the set concentration threshold of the absorption tower, the cyclone overflow is transported to the accident slurry tank 4, and when the chloride ion concentration value in the cyclone overflow is less than the set concentration threshold of the absorption tower, the cyclone overflow is transported to the absorption tower; The accident slurry tank 4 is used to carry out sedimentation treatment on the cyclone overflow from the gypsum overflow slurry tank 3, and then transport the upper clear liquid to the wastewater concentration tower 7, and the lower sedimentation concentrated slurry to the gypsum slurry buffer tank 1; The wastewater concentration tower 7 is used to concentrate the clear liquid from the accident slurry tank 4, and when the chloride ion concentration value of the slurry in the wastewater concentration tower 7 reaches the concentration threshold value required by the drying system, the concentrated slurry is transported to the drying system for drying treatment; It also includes a pH value adjusting device, which includes an alkali metering tank 61, an alkali metering pump 62 and a pH measuring module 63 arranged inside the wastewater concentration tower 7, and the alkali metering pump 62 is used to measure a corresponding amount of alkaline solution from the alkali metering tank 61 according to the pH value of the slurry measured by the pH measuring module 63 and transport it to the wastewater concentration tower 7; A wastewater transfer tank 5 is also provided between the accident slurry tank 4 and the wastewater thickening tower 7. The upper clear liquid of the accident slurry tank 4 is first transported to the wastewater transfer tank 5, and then transported to the wastewater thickening tower 7 via the wastewater transfer tank 5; a plurality of overflow ports are provided on the upper side of the accident slurry tank 4 from top to bottom.

[0032] In actual application, the desulfurized wastewater from the absorption tower is first stored in the gypsum slurry buffer tank 1. When the desulfurized wastewater in the gypsum slurry buffer tank 1 is stored to a set value, the buffer delivery pump 11 is used to deliver the desulfurized wastewater to the gypsum cyclone 2. Then, the gypsum cyclone 2 performs solid-liquid separation on the incoming desulfurized wastewater, and then delivers the bottom cyclone concentrated slurry to the belt conveyor, and the upper cyclone overflow is delivered to the gypsum overflow slurry tank 3. Then, the gypsum overflow slurry tank 3 uses a chloride ion monitoring instrument to monitor the incoming cyclone. The concentration of chloride ions in the overflow is monitored, and when the concentration of chloride ions in the cyclone overflow is greater than the set concentration threshold of the absorption tower, the slurry delivery pump 32 is used to deliver the cyclone overflow to the accident slurry tank 4. When the concentration of chloride ions in the cyclone overflow is less than the set concentration threshold of the absorption tower, the slurry return pump 31 is used to deliver the cyclone overflow to the absorption tower to avoid directly delivering the cyclone overflow that can still be used in the absorption tower to the accident slurry tank 4 for invalid treatment; then the accident slurry tank 4 is used to After the cyclone overflow is precipitated for 9 hours, the upper clear liquid is diverted to the wastewater transfer tank 5 through an overflow port, and the lower precipitated concentrated slurry is transported to the gypsum slurry buffer tank 1 by the precipitated concentrated slurry delivery pump 41 and processed by the gypsum cyclone 2 to further improve the gypsum crystal quality; then when the clear liquid in the wastewater transfer tank 5 reaches the set value, the clear liquid is transported to the wastewater concentration tower 7 by the wastewater transfer pump 51; then the wastewater concentration tower 7 concentrates and reduces the incoming clear liquid, and when the chloride ion monitor When the meter monitors that the chloride ion concentration of the slurry in the wastewater concentration tower 7 is greater than 100000 ppm, the concentrated slurry is transported to the drying system for drying treatment to achieve zero discharge treatment of desulfurization wastewater. During the concentration process, the pH value of the slurry is measured in real time by the pH measurement module 63. The alkali metering pump 62 measures a corresponding amount of alkaline solution from the alkali metering tank 61 according to the pH value of the slurry measured by the pH measurement module 63 and transports it to the wastewater concentration tower 7, so that the pH value of the slurry is stabilized at 7-9.

[0033] It has been tested that the desulfurization wastewater treatment system of the present invention can effectively improve the treatment efficiency of desulfurization wastewater when it is actually applied, compared with the desulfurization wastewater treatment scheme based on chemical precipitation method in the prior art, and does not need to use a large amount of chemical agents and set up multiple independent sludge treatment devices. It has the advantages of low investment cost and high gypsum quality for commercial use.

[0034] Example 2 The embodiment is implemented with reference to Example 1, except that a water distributor 73 for introducing the clear liquid in the accident slurry tank 4 and a heat source air pipe outlet section 711 of the folded pipe 71 directly below the water distributor 73 are provided on the upper part of the wastewater concentrating tower 7, a plurality of air outlet holes are provided on the upper surface of the heat source air pipe outlet section 711, and a plurality of liquid drainage holes are provided on the lower surface; the connection angle between the folded pipe section of the folded pipe 71 and its heat source air pipe outlet section 711 is 120°; the wastewater concentrating tower 7 also includes a circulating spraying device, which includes a sprayer 72 provided between the water distributor 73 and the heat source air pipe outlet section 711 and a circulating pump 74 for circulating the slurry in the wastewater concentrating tower 7 to the sprayer 72 for spraying.

[0035] It has been tested that the desulfurization wastewater treatment system of the present invention can further effectively improve the treatment efficiency of desulfurization wastewater compared with the solution in Example 1.

[0036] Example 3 Refer to Example 2 for implementation, except that the smoke inlet of the folded pipe 71 is connected to the smoke inlet of the inlet flue of the desulfurization absorption tower through a pipeline, and the smoke outlet at the top of the wastewater concentration tower 7 is connected to the smoke return outlet of the inlet flue of the desulfurization absorption tower; a demister 76 is also arranged directly above the water distributor 73.

[0037] It has been found that the desulfurization wastewater treatment system of the present invention can further achieve effective utilization of the flue gas waste heat at the inlet flue of the desulfurization absorption tower while not affecting the stability of the desulfurization absorption tower, compared with the solution in Example 2.

[0038] Example 4 Refer to Example 3, except that the desulfurization wastewater in the gypsum slurry buffer tank 1 is transported to the gypsum cyclone 2 through a buffer delivery pump 11. The buffer delivery pump 11 is driven by a variable frequency motor to adjust the inlet pressure of the gypsum cyclone 2 in real time according to the unit load and / or gypsum quality.

[0039] It has been found that the desulfurization wastewater treatment system of the present invention can further effectively improve the quality of gypsum compared with the solution in Example 3.

[0040] The desulfurization wastewater treatment system provided by the present invention can achieve the treatment of desulfurization wastewater and improve the crystallization quality of gypsum by setting a gypsum cyclone for solid-liquid separation treatment of desulfurization wastewater from a gypsum slurry buffer tank. By setting a gypsum overflow slurry tank, when the chloride ion content of the cyclone overflow in the gypsum overflow slurry tank is low, the cyclone overflow can be returned to the absorption tower to continue to participate in the desulfurization reaction, thereby ensuring the desulfurization wastewater treatment efficiency while improving the utilization rate of the slurry and saving the amount of limestone slurry; by setting an accident slurry tank and conveying the lower precipitate to the gypsum slurry buffer tank, not only the treatment effect of the desulfurization wastewater and the crystallization quality of the gypsum can be improved, but also there is no need to set up a sludge treatment device separately; and by setting a wastewater concentration tower, not only can the concentration and reduction of desulfurization wastewater be achieved based on the effective utilization of the flue gas waste heat of the desulfurization system, but also zero discharge of desulfurization wastewater can be achieved based on the cooperation with the drying system.

[0041] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations. However, these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A desulfurization wastewater treatment system, characterized in that: The desulfurization wastewater treatment system includes: A gypsum slurry buffer tank (1), used for buffering and storing desulfurization wastewater from the absorption tower; The gypsum cyclone (2) is used to perform solid-liquid separation on the desulfurization wastewater from the gypsum slurry buffer tank (1), and then transport the bottom cyclone concentrated slurry to the belt conveyor, and transport the upper cyclone overflow to the gypsum overflow slurry tank (3); The gypsum overflow slurry tank (3) is used to monitor the chloride ion concentration value in the cyclone overflow from the gypsum cyclone (2), and when the chloride ion concentration value in the cyclone overflow is greater than the set concentration threshold of the absorption tower, the cyclone overflow is transported to the accident slurry tank (4); when the chloride ion concentration value in the cyclone overflow is less than the set concentration threshold of the absorption tower, the cyclone overflow is transported to the absorption tower; An accident slurry tank (4) is used to carry out sedimentation treatment on the cyclone overflow from the gypsum overflow slurry tank (3), and then transport the upper clear liquid to the wastewater concentration tower (7), and transport the lower sedimentation concentrated slurry to the gypsum slurry buffer tank (1); The wastewater concentration tower (7) is used to concentrate and reduce the clear liquid from the accident slurry tank (4), and when the chloride ion concentration value of the slurry in the wastewater concentration tower (7) reaches the concentration threshold value required by the drying system, the concentrated slurry is transported to the drying system for drying treatment.

2. The desulfurization wastewater treatment system according to claim 1, characterized in that: The upper portion of the wastewater concentration tower (7) is provided with a water distributor (73) for introducing clear liquid into the accident slurry tank (4), and a heat source air pipe outlet section (711) of a folded pipe (71) arranged directly below the water distributor (73); a plurality of air outlet holes are provided on the upper surface of the heat source air pipe outlet section (711), and a plurality of liquid discharge holes are provided on the lower surface.

3. The desulfurization wastewater treatment system according to claim 2, characterized in that: The wastewater concentration tower (7) further comprises a circulating spraying device, the circulating spraying device comprising a sprayer (72) arranged between the water distributor (73) and the heat source air pipe outlet section (711) and a circulating pump (74) for circulating the slurry in the wastewater concentration tower (7) to the sprayer (72) for spraying.

4. The desulfurization wastewater treatment system according to claim 2, characterized in that: The connection angle between the folded pipe section of the folded pipe (71) and its heat source air pipe outlet section (711) is 100-150°.

5. The desulfurization wastewater treatment system according to claim 2, characterized in that: The smoke inlet of the folded pipe (71) is connected to the smoke inlet of the desulfurization absorption tower inlet duct through a pipeline, and the smoke outlet at the top of the wastewater concentration tower (7) is connected to the smoke return outlet of the desulfurization absorption tower inlet duct.

6. The desulfurization wastewater treatment system according to claim 5, characterized in that: A demister (76) is also provided directly above the water distributor (73).

7. The desulfurization wastewater treatment system according to claim 2, characterized in that: The invention also comprises a pH value regulating device, the pH value regulating device comprising an alkali metering tank (61), an alkali metering pump (62) and a pH measuring module (63) arranged inside the wastewater concentration tower (7); the alkali metering pump (62) is used to measure a corresponding amount of alkaline solution from the alkali metering tank (61) according to the pH value of the slurry measured by the pH measuring module (63) and transport the alkaline solution to the wastewater concentration tower (7).

8. The desulfurization wastewater treatment system according to claim 1, characterized in that: The desulfurized wastewater in the gypsum slurry buffer tank (1) is transported to the gypsum cyclone (2) via a buffer delivery pump (11). The buffer delivery pump (11) is driven by a variable frequency motor and is used to adjust the inlet pressure of the gypsum cyclone (2) in real time according to the unit load and / or gypsum quality.

9. The desulfurization wastewater treatment system according to claim 1, characterized in that: A wastewater transfer tank (5) is also provided between the accident slurry tank (4) and the wastewater concentration tower (7), and the upper clear liquid of the accident slurry tank (4) is first transported to the wastewater transfer tank (5), and then transported to the wastewater concentration tower (7) via the wastewater transfer tank (5).

10. The desulfurization wastewater treatment system according to claim 1 or 9, characterized in that: The upper side of the accident slurry tank (4) is provided with a plurality of overflow openings from top to bottom.

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