CN216191594U - High concentration hydrofluoric acid wastewater pretreatment system - Google Patents

Abstract

The utility model discloses a high-concentration hydrofluoric acid wastewater pretreatment system, which relates to the field of wastewater treatment and comprises a sequencing batch reactor replacing a traditional four-series reactor, wherein the sequencing batch reactor is connected with a sludge dewatering machine through a feeding pump, so that high-concentration hydrofluoric acid wastewater is subjected to precipitation reaction through the sequencing batch reactor, precipitates are discharged, a pH value in the reactor is monitored in a flow-through groove type instrument installation mode, and the addition amount of lime milk is automatically controlled through an automatic lime adding valve to regulate and control the neutralization reaction in the reactor. The utility model replaces four conventional reactors, a sedimentation tank, an intermediate water tank, a filter, a sludge tank and a sludge dewatering machine in series by two process sections, and the total number of the process sections is 9, thereby greatly reducing the treatment flow of high-concentration hydrofluoric acid.

Description

High concentration hydrofluoric acid wastewater pretreatment system

Technical Field

The utility model relates to the field of wastewater treatment, in particular to a high-concentration hydrofluoric acid wastewater pretreatment system generated in the production process of a solar panel in the photovoltaic industry.

Background

In the process of producing a solar cell panel in the photovoltaic industry, hydrofluoric acid is needed to clean silicon dioxide impurities on the surface of a silicon wafer, the cleaning is carried out by using the hydrofluoric acid, the used hydrofluoric acid is used as wastewater to be discharged to a wastewater treatment station, one strand of high-concentration hydrofluoric acid wastewater and one strand of low-concentration hydrofluoric acid wastewater generated by rinsing residual hydrofluoric acid on the surface of the cell panel can appear in the production process, lime and calcium chloride are generally adopted for defluorination reaction in the treatment process to enable fluorine in water to form calcium fluoride precipitate, in order to ensure that the effluent meets the requirement that the fluoride in the discharge standard is less than 8mg/L, the excessive addition of lime and calcium chloride is needed to enable the fluoride to fully react into calcium fluoride, and due to the high concentration of the high-concentration hydrofluoric acid, the scaling of pipelines and equipment is easy to appear in the treatment process of a sedimentation tank and a reaction tank after the lime is added, and the equipment is scaled to cause a large amount of equipment maintenance work, the normal operation of each process link is seriously influenced, so a short-flow pretreatment device is needed, the content of fluoride in the high-concentration hydrofluoric acid wastewater is reduced, and the method is the key for treating the high-concentration hydrofluoric acid wastewater in the photovoltaic industry.

At present, the conventional four reactors connected in series, a sedimentation tank, an intermediate water tank, a filter, a sludge tank and a sludge dewatering machine are generally adopted in the industry for reducing the content of fluoride in hydrofluoric acid wastewater, 9 process sections are counted, the process is complex, more equipment is involved, and the cost is high.

Disclosure of Invention

Aiming at the problems in the prior art, the utility model aims to reduce the content of fluoride in high-concentration hydrofluoric acid wastewater entering a comprehensive wastewater treatment system for solar panel production wastewater in the photovoltaic industry, and provides a method for removing most of fluoride in wastewater by adopting a short-flow treatment system in a pretreatment process section.

The utility model discloses a high-concentration hydrofluoric acid wastewater pretreatment system, which comprises a reactor for pretreating hydrofluoric acid wastewater and a feeding pump connected with a discharge port at the bottom of the reactor, wherein a mud-water mixture reacted in the reactor can be pumped into a sludge dewatering machine connected with the reactor to separate mud and water of the mixture, so that calcium fluoride is separated from water in the form of solid sludge. The leachate generated by the sludge dewatering treatment enters a comprehensive wastewater treatment system for further treatment.

The reactor is a sequencing batch reactor, a wastewater water inlet and a lime milk feeding port are formed in the top of the reactor, the reactor comprises a sequencing batch reaction tank serving as a reactor main body, a stirrer is arranged in the reactor main body and used for stirring a mixture fed into the reaction tank to accelerate the pretreatment process, and a reaction tank liquid level meter is arranged at the top of the reaction tank and used for controlling the water inflow in the reaction tank.

As a further improvement of the utility model, a lime milk feeding port at the top of the reactor is fixedly provided with a lime automatic feeding valve, so that the lime feeding amount is automatically controlled.

As a further improvement of the utility model, a sampling pump is connected to the side wall of the reactor, the discharge port of the sampling pump is connected with a circulation tank, the discharge port of the circulation tank is connected with the reaction tank, and a pH meter is arranged on the circulation tank to monitor the pH value of the mixed liquid in the circulation tank.

As a further improvement of the utility model, the reaction tank is in a bucket shape, so that the accumulation of the sediment after the reaction to the bottom of the equipment is facilitated and the sediment is discharged.

The utility model has the beneficial effects that: pretreatment systems more than adopting replaces four conventional series connection reactors, sedimentation tank, middle pond, filter, sludge impoundment, sludge dewaterer through two technology sections, totally 9 technology sections, reduce the processing procedure of high concentration hydrofluoric acid by a wide margin, because conveying equipment only needs 1 water pump, the pipeline only has one section pipeline from reactor to sludge dewaterer, can reduce the influence of calcium fluoride scale deposit by a wide margin, makes the processing system operation more stable.

Drawings

FIG. 1 is a schematic process flow diagram of the pretreatment system of the present invention.

FIG. 2 is a schematic view of the structure of a sequencing batch reactor of the present invention.

The method comprises the following steps of 1-sequencing batch reactor, 2-feeding pump, 3-sludge dewatering machine, 101-reaction tank, 102-liquid level meter, 103-stirrer, 104-sampling pump, 105-circulation tank, 106-pH meter and 107-lime automatic feeding valve.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Referring to fig. 1, the high-concentration hydrofluoric acid wastewater pretreatment system of the present invention includes a sequencing batch reactor 1 for pretreating hydrofluoric acid wastewater, where the sequencing batch reactor 1 replaces a conventional series reactor and a conventional reaction tank, and serves as a container for reacting hydrofluoric acid wastewater with an additive, a discharge port at the bottom of the sequencing batch reactor 1 is connected to a feed pump 2, and a sludge-water mixture reacted in the sequencing batch reactor 1 is pumped into a sludge dewatering machine 3 connected thereto for sludge-water separation of the mixture, so that calcium fluoride is separated from water in the form of solid sludge, and a leachate treated by the sludge dewatering machine 3 enters a comprehensive wastewater treatment system for further treatment.

Referring to fig. 2, a sequencing batch reactor 1 of the present invention includes a reaction tank 101 for containing hydrofluoric acid wastewater and additives to react, in which lime, a coagulant and a flocculant are added, and in which hydrofluoric acid is reacted into calcium fluoride solids; reaction tank 101 top is provided with level gauge 102, is used for control the inflow in the reaction tank 101, the volume design of sequencing batch reactor 1 matches with sludge dewaterer 3, and single cycle uses sludge dewaterer 3 to accomplish the feeding as the terminal point, the inflow of sequencing batch reactor 1 uses level gauge 102 to detect high liquid level as the terminal point, and then gets into and adds the medicine reaction process, and the pump stopping of feed pump 2 is interlocked with the low liquid level of sequencing batch reactor 1, and the pump stopping after the low liquid level appears, and is interlocked with sludge dewaterer 3's feeding pressure simultaneously, explains that sludge dewaterer 3 has advanced sludge after reaching feeding pressure, then feed pump 2 needs the shut down, and feed pump 2 shut down when two above conditions are arbitrary, and a duty cycle of sequencing batch reactor 1 is accomplished.

The top of the reaction tank 101 is further provided with a wastewater inlet and a lime milk feeding port for feeding hydrofluoric acid wastewater and lime milk into the reaction tank, the lime milk feeding port is further provided with an automatic lime feeding valve 107 for realizing automation of feeding lime milk by closing the automatic lime feeding valve, and a stirrer 103 is fixedly arranged inside the reaction tank 101 for stirring a mixture fed into the reaction tank 101 to accelerate the process of fixing hydrofluoric acid wastewater in the reaction tank 101 to form calcium fluoride.

Because the high-concentration hydrofluoric acid waste water can produce extremely strong corruption to the glass electrode of pH meter, causes the instrument life-span to reduce by a wide margin, this pretreatment systems be in reaction tank 101 lateral wall connects sampling pump 104, the discharge outlet of sampling pump 104 is connected with circulation tank 105, the discharge outlet of circulation tank 105 with reaction tank 101 is connected, it can monitor the mixed liquid pH value in circulation tank 105 to be provided with pH meter 106 on the circulation tank 105, throw with used lime cream ration and stir half an hour later and open sampling pump 104 and draw water to circulation tank 105 and supply pH meter 106 to detect, pH meter 106 and lime are thrown valve 107 automatically and are carried out the interlock, and pH is less than 8.5 and throws lime cream, and pH is higher than 8.5 and stops throwing and throw.

The treatment process comprises the steps that high-concentration hydrofluoric acid wastewater enters a sequencing batch reactor 101, water inflow is controlled through a liquid level meter 102, water inflow is stopped after the liquid level is high, a stirrer 103 and an automatic lime adding valve 107 are started, lime adding amount is automatically controlled through a pH meter 106 and the automatic lime adding valve 107, the automatic lime adding valve 107 is stopped when the pH value is more than 8.5, one operation cycle of the sequencing batch reactor 1 is divided into 3 processes of feeding, adding chemicals for reaction, pumping and drying through a feeding pump 2, and the feeding and pumping steps are controlled to start and end through the liquid level meter 102 of the reactor.

It will be evident to those skilled in the art that the utility model is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the utility model being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

Claims (5)

1. A high-concentration hydrofluoric acid wastewater pretreatment system comprises a reactor for pretreating hydrofluoric acid wastewater, and is characterized by further comprising a feeding pump (2) connected with a discharge port at the bottom of the reactor, wherein a muddy water mixture after reaction in the reactor can be pumped into a sludge dewatering machine (3) connected with the feeding pump for carrying out muddy water separation on the mixture, so that calcium fluoride is separated from water in the form of solid sludge; the reactor is a sequencing batch reactor (1), a wastewater water inlet and a lime milk feeding port are formed in the top of the reactor, the reactor comprises a sequencing batch reaction tank (101) serving as a reactor main body, a stirrer (103) is arranged in the reactor main body and used for stirring a mixture fed into the reaction tank (101) to accelerate a pretreatment process, and a reaction tank liquid level meter (102) is arranged on the top of the reaction tank (101) and used for controlling the water inflow in the reaction tank (101).

2. The pretreatment system of wastewater containing high concentration hydrofluoric acid according to claim 1, wherein the lime milk inlet at the top of the reaction tank (101) is fixedly provided with an automatic lime adding valve (107) to realize automatic control of lime adding amount.

3. The pretreatment system of wastewater containing hydrofluoric acid of claim 2, wherein the side wall of the reaction tank (101) is connected to a sampling pump (104), the outlet of the sampling pump (104) is connected to a circulation tank (105), and the outlet of the circulation tank (105) is connected to the reaction tank (101).

4. The pretreatment system for wastewater containing hydrofluoric acid of high concentration according to claim 3, wherein said circulation tank (105) is provided with a pH meter (106) for monitoring pH of the mixed liquid in the circulation tank (105).

5. The pretreatment system of claim 1, wherein said reaction tank (101) is shaped as a bucket to facilitate accumulation of the precipitate to the bottom for discharge.

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