Power plant desulfurization wastewater application treatment system

Abstract

A power plant desulfurization wastewater application treatment system is used for treating wastewater from a desulfurization system. Comprising a main wastewater tank and an auxiliary wastewater tank, high-concentration salt-containing wastewater from a thermal power plant flows out from the salt-containing wastewater outlet and flows into the main wastewater tank; a low-position liquid outlet of the main wastewater tank is communicated with a liquid inlet of the water using mechanism; a high-level liquid outlet of the main wastewater tank is communicated with the auxiliary wastewater tank; the auxiliary wastewater tank is provided with a liquid outlet connected with a slag bin water spraying system; the desulfurization wastewater can be fully utilized in multiple ways, water is deposited and screened, one part of the water is used for spraying the slag bin, and the spraying uniformity is improved; the other part conveys other water, and two water inlet sources are provided and selected according to the water demand. The treatment capacity and the application effect of on-site treatment and absorption of the desulfurization wastewater are improved.

Description

Technical Field

[0001] The invention relates to the field of thermal power generation, and in particular to an application and treatment system for desulfurization wastewater in a power plant. Background Art

[0002] Wet flue gas desulfurization is the mainstream process for flue gas desulfurization in thermal power plants in my country. Coal, as the main fuel for coal-fired units in thermal power plants, contains a large amount of sulfides and heavy metals. During the wet desulfurization process, the slurry in the desulfurization absorption tower is repeatedly recycled. During this process, the soluble salts in the slurry are continuously concentrated. In order to maintain the desulfurization performance of the system, the slurry needs to be continuously replenished and updated, and the wastewater containing a large amount of heavy metal ions needs to be discharged and treated. This part of the discharged wastewater comes from the flue gas desulfurization system, so it is called "desulfurization wastewater". The water quality of desulfurization wastewater is acidic, containing a large amount of suspended solids, metal ions and anions such as F-, SO42-, C1- and trace amounts of heavy metal ions. Although the amount of desulfurization wastewater is not large, if it is not treated in time, it will have a great impact on the desulfurization system equipment and the environment, such as corrosion.

[0003] The wastewater generated by the desulfurization process is collected in the wastewater cyclone box through pipelines for mixing and storage. The wastewater in the box is sent to the wastewater cyclone through the wastewater cyclone pump for secondary separation. The wastewater overflowing from the wastewater cyclone flows into the reaction neutralization box. Then the wastewater overflows from the reaction neutralization box into the sedimentation tank, flocculation tank, and thickening and clarification tank in turn, and is discharged to the ash storage through the wastewater discharge pump; the sludge at the bottom of the thickening and clarification tank is discharged to the plate and frame filter press through the sludge conveying pump for dehydration treatment. The treated sludge is transported to the ash yard by vehicle for stacking, and the filtrate water flowing out of the plate and frame filter press is transported to the filtrate pool, and finally enters the neutralization box for further treatment.

[0004] However, the existing wastewater treatment system has the following problems: the plate and frame filter press has a high failure rate; the wastewater cyclone is frequently blocked; there is serious deposition in the flocculation box; the main plant ash storage mixes dry ash with desulfurization wastewater to utilize the wastewater, but the amount of wastewater used in the main plant ash storage is currently small and cannot achieve zero wastewater discharge in the entire plant. Summary of the invention

[0005] The purpose of the present invention is to realize multiple full utilization of desulfurization wastewater, and propose a desulfurization wastewater treatment system for a power plant.

[0006] A power plant desulfurization wastewater treatment system, used to treat wastewater from a desulfurization system; comprising a main wastewater tank and an auxiliary wastewater tank; characterized in that:

[0007] The main wastewater tank is fluidly connected to the salty wastewater outlet of the desulfurization system of the thermal power plant, and the high-concentration salty wastewater from the thermal power plant flows out from the salty wastewater outlet and flows into the main wastewater tank;

[0008] One side of the main wastewater tank close to the bottom is connected to the liquid inlet of the water-using mechanism through a low-position liquid outlet;

[0009] One side of the main wastewater tank near the top is connected to the auxiliary wastewater tank through a high-position liquid outlet;

[0010] A liquid outlet is arranged on the auxiliary wastewater tank to connect to the slag bin water spraying system.

[0011] The beneficial effects of the present invention are:

[0012] Compared with the prior art, the present invention can make full use of desulfurization wastewater in multiple ways, deposit and screen the water quality, use one part for spraying slag bin to improve spraying uniformity, and transport other water, provide two water sources, and choose according to water demand, so as to improve the treatment capacity and application effect of on-site treatment and absorption of desulfurization wastewater. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a diagram of a power plant desulfurization wastewater treatment system.

[0014] In the figure: 1. Main wastewater tank; 2. Auxiliary wastewater tank; 3. Liquid replenishment pump; 4. Pressure pump; 5, 6, 7 slag bins; 51, 52, 53 spray pipe group; 8, 9 filters; 10. Water use mechanism. DETAILED DESCRIPTION

[0015] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0016] A power plant desulfurization wastewater treatment system is used to treat wastewater from a desulfurization system.

[0017] It comprises a main wastewater tank 1, and a liquid inlet on the top of the main wastewater tank is connected to the desulfurization system of the power plant.

[0018] The main wastewater tank 1 is fluidly connected to the salt-containing wastewater outlet of the desulfurization system of the thermal power plant. High-concentration salt-containing wastewater from the thermal power plant flows out from the salt-containing wastewater outlet and flows into the main wastewater tank 1.

[0019] The wastewater in the main wastewater tank 1 will have a residence sedimentation time, during which corresponding sedimentation occurs, wherein the solid impurity concentration in the lower part is higher, while the liquid solid impurity concentration in the upper part is lower.

[0020] One side of the main wastewater tank 1 close to the bottom is connected to the liquid inlet of the water-using mechanism 10 through a low-position liquid outlet.

[0021] One side of the main wastewater tank 1 close to the top is connected to the auxiliary wastewater tank 2 through a high-position liquid outlet.

[0022] The volume of the main wastewater tank 1 is larger than that of the auxiliary wastewater tank 2, by about 5-10 times.

[0023] The wastewater in the main wastewater tank 1 will have a residence sedimentation time, during which corresponding sedimentation occurs, wherein the solid impurity concentration in the lower part is higher, while the liquid solid impurity concentration in the upper part is lower.

[0024] A liquid outlet is arranged on the auxiliary wastewater tank 2 to connect to the slag bin water spraying system. A pressure pump 4 is arranged on the connecting pipeline.

[0025] The slag bin water spraying system includes a first slag bin 5 , a second slag bin 6 , and a third slag bin 7 .

[0026] In the slag bin water spraying system, a spray pipe is arranged in each boiler slag bin, one end of the spray pipe is connected to the auxiliary wastewater tank 2, and the other end of the spray pipe is arranged above the boiler slag bin. High-concentration saline wastewater from the thermal power plant can be sprayed onto the hot slag in the boiler slag bin through the spray pipe. Under the action of the hot slag in the boiler slag bin, the water in the high-concentration saline wastewater evaporates, and the hot slag is cooled, and the evaporated industrial salt is attached to the dry slag in a solid form, thereby eliminating the strong corrosiveness of the high-concentration saline wastewater in liquid form. At the same time, the hot slag is discharged in a dry form, which is conducive to subsequent comprehensive utilization.

[0027] The spray pipes in a slag bin are divided into several zones, each zone corresponds to an independent spray pipe group, including spray pipe groups 51, 52, and 53.

[0028] In order to control the flow distribution of high-concentration salt-containing wastewater in the slag bin, a temperature-sensing camera is installed in the boiler slag bin to obtain the slag image inside the slag bin in real time. After image processing and analysis, the temperature distribution plane diagram of the hot slag in the slag bin is obtained to increase the flow in the high-temperature area and reduce the flow in the low-temperature area.

[0029] The side near the top of the main wastewater tank 1 is connected to the auxiliary wastewater tank 2 through a high-position liquid outlet. The liquid with a low solid impurity concentration in the upper part of the main wastewater tank can be transported to the auxiliary wastewater tank through the replenishment pump 3 on the pipeline. The auxiliary wastewater tank is used for the slag bin water spraying system. The low solid impurity concentration can avoid the influence of impurities on the water spraying system and cause pipeline blockage.

[0030] The replenishing pump 3 is connected to the control unit of the water spraying system (not shown in the figure), and the control unit is also connected to the temperature sensing camera, the liquid level meter in the auxiliary wastewater tank, and the spray pipe flow regulating valve. According to the sensed and identified temperature distribution of the slag area, the spray pipe flow regulating valve is adjusted to control the delivery flow to achieve uniform cooling and spraying in the slag bin.

[0031] At the same time, according to the liquid level in the auxiliary wastewater tank 2 and the spray output flow rate, the opening frequency and duration of the liquid replenishment pump 3 are calculated and controlled to ensure that the auxiliary wastewater tank 2 has sufficient liquid storage and does not store liquid for too long to cause retention and sedimentation.

[0032] The return liquid pipe of the slag bin water spraying system is connected to the auxiliary waste water tank 2 to transport the excess water after spraying back to the auxiliary waste water tank 2.

[0033] The liquid return pipe is also connected to the water-using mechanism 10 through a branch line, and the excess water is transported to the water-using mechanism 10 through valve control.

[0034] One side of the main wastewater tank 1 close to the bottom is connected to the liquid inlet of the water-using mechanism 10 through a low-position liquid outlet.

[0035] The low-position liquid outlet outputs liquid with a relatively high solid impurity concentration, which can be transported to the water-using mechanism 10 .

[0036] In order to ensure that the water entering the slag bin water spraying system has low impurities, filters 8 and 9 are added at the inlets of the replenishment pump 3 and the booster pump 4 to filter out solid impurities. The filters can be cleaned and replaced regularly.

[0037] The water-using mechanism includes a coal yard flushing pool, an ash storage humidification flushing pool, and a desulfurization absorption tower pit pool. The coal yard flushing pool, the ash storage humidification flushing pool, and the desulfurization absorption tower pit pool are provided with a water valve at the liquid inlet. Through the water valve, the wastewater in the low-level liquid outlet is transported to the coal yard flushing pool, the ash storage humidification flushing pool, and the desulfurization absorption tower pit pool to reuse the wastewater. The water-using mechanism can obtain the supply water source from the main wastewater tank 1 and the slag bin water spraying system according to the water quality requirements. When used for dry ash mixing, the water source with higher impurities in the main wastewater tank 1 can be introduced; when used for flushing operations, the water source with lower impurities in the return pipe of the slag bin water spraying system can be introduced.

[0038] Finally, it should be noted that the above description is only an explanation of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail, those skilled in the art can still modify the technical solutions described above or replace some of the technical features with equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A power plant desulfurization wastewater application treatment system, used to treat wastewater from the desulfurization system; including a main wastewater tank and an auxiliary wastewater tank; characterized in that: The main wastewater tank is fluidically connected to the salty wastewater outlet of the desulfurization system of the thermal power plant, and the high-concentration salty wastewater from the thermal power plant flows out from the salty wastewater outlet and flows into the main wastewater tank; One side of the main wastewater tank close to the bottom is connected to the liquid inlet of the water-using mechanism through a low-position liquid outlet; One side of the main wastewater tank near the top is connected to the auxiliary wastewater tank through a high-position liquid outlet; A liquid outlet is arranged on the auxiliary wastewater tank to connect to the slag bin water spraying system.

2. According to claim 1, a power plant desulfurization wastewater application treatment system is characterized in that: The slag bin water spraying system includes several slag bins; a spray pipe is arranged in each slag bin, one end of the spray pipe is connected to the auxiliary waste water tank, and the other end of the spray pipe is arranged above the boiler slag bin.

3. According to claim 2, a power plant desulfurization wastewater application treatment system is characterized in that: The spray pipe in a slag bin is divided into several spray zones, each spray zone corresponds to an independent spray pipe group, including several spray pipe groups, and the flow of each independent spray pipe group is regulated by a flow regulating valve.

4. A power plant desulfurization wastewater application treatment system according to claim 3, characterized in that: A temperature-sensing camera is installed in the boiler slag bin to obtain the real-time image of the slag inside the slag bin, and obtain the temperature distribution plane diagram of the hot slag in the slag bin through image processing and analysis; the control unit is connected to the temperature-sensing camera and the spray pipe flow regulating valve; according to the sensed and identified temperature distribution plane diagram of the slag area, the spray pipe flow regulating valve is adjusted to control the delivery flow.

5. A power plant desulfurization wastewater application treatment system according to claim 4, characterized in that: A replenishing pump is arranged in the connecting pipeline between the main wastewater tank and the auxiliary wastewater tank; the control unit is also connected to the liquid level gauge in the auxiliary wastewater tank; according to the liquid level in the auxiliary wastewater tank and the spray output flow rate, the opening frequency and duration of the replenishing pump are calculated and controlled to ensure that there is enough liquid stored in the auxiliary wastewater tank and that the liquid will not stay and deposit for too long.

6. The power plant desulfurization wastewater application treatment system according to claim 1, characterized in that: The return pipe of the slag bin spraying system is connected to the auxiliary wastewater tank to transport the excess water after spraying back to the auxiliary wastewater tank; the return pipe is also connected to the water-using mechanism through a branch line, and the excess water is transported to the water-using mechanism through valve control.

7. A power plant desulfurization wastewater application treatment system according to claim 6, characterized in that: The water-using institutions include the coal yard flushing pool, the ash storage humidification flushing pool and the desulfurization absorption tower pit pool; the water supply is obtained from the main wastewater tank and the slag bin spraying system, and the water source with higher impurities in the main wastewater tank can be introduced, or the water source with lower impurities in the return pipe of the slag bin spraying system can be introduced.

8. The power plant desulfurization wastewater application treatment system according to claim 1, characterized in that: Filters are installed at the high-level outlet of the main wastewater tank and the outlet of the auxiliary wastewater tank.

9. A power plant desulfurization wastewater application treatment system according to claim 8, characterized in that: A filter is installed at the inlet of the replenishing pump connected to the high-level liquid outlet of the main wastewater tank and the booster pump connected to the liquid outlet of the auxiliary wastewater tank.

10. A power plant desulfurization wastewater application treatment system according to claim 8, characterized in that: The wastewater in the main wastewater tank will have a residence sedimentation time, wherein the solid impurity concentration in the lower part is higher, while the liquid solid impurity concentration in the upper part is lower.

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