Treatment system for fluorine-containing waste brine

Abstract

The utility model relates to the technical field of fluorine-containing waste water treatment, in particular to a fluorine-containing waste brine treatment system which comprises a neutralizing tank, a first feeding pipeline, a second feeding pipeline and a discharging pipeline are arranged in the neutralizing tank, the first feeding pipeline is connected with a fluorine-containing waste brine tank, the second feeding pipeline is connected with a lime water tank, and the discharging pipeline is connected with a lime water tank. The discharging pipeline is connected with the hydrocyclone, a bottom outlet of the hydrocyclone is connected with the drying device through the feeding device, an upper outlet of the hydrocyclone is connected with the buffer pool through the clear liquid pipeline, the buffer pool is sequentially connected with the triple-effect evaporation device and the centrifugal separation device, and a liquid outlet of the centrifugal separation device is connected with the buffer pool through the concentrated salt liquid backflow pipeline. According to the device, calcium fluoride solid and liquid generated after calcium ions are added into fluorine-containing waste brine can be quickly separated without large-volume filtering equipment, the separation effect is obvious, and the occupied area is small; the heat energy in the concentration and crystallization process of clear liquid after solid-liquid separation can be fully utilized, and the energy consumption is reduced.

Description

TECHNICAL FIELD

[0001] The utility model relates to fluorine-containing wastewater treatment technical field, concretely relates to a kind of fluorine-containing waste brine processing system. BACKGROUND

[0002] Kunfeng acid (C9H 10 ClF3O2, trifluorochloro acid) is an important chemical production intermediate, which can be used for synthesizing efficient pyrethroid. The existing kunfeng acid industrial production process is mainly to use methyl anthranilate and trifluorotrichloroethane (F113a) as raw materials, to produce kunfeng acid through addition, cyclization, hydrolysis saponification and acidification three-step reaction, and a large amount of wastewater containing organic matter, sodium chloride and fluoride ions will be produced in the production process. After the organic matter is recovered by evaporation, a large amount of fluorine-containing waste brine with high fluoride ion concentration will still be produced, which has high pollution risk and high recovery difficulty, and is difficult to treat.

[0003] The existing fluorine-containing waste brine treatment process includes chemical precipitation method, adsorption method, ion exchange method, membrane filtration method and electrochemical method. The ion exchange method, membrane filtration method and electrochemical method have high treatment cost and are not suitable for industrial large-scale application. The filler of the adsorption method is difficult to regenerate, and the adsorbed fluoride ions cannot be recovered, resulting in large resource waste. Therefore, the existing technology mainly uses the precipitation method to treat fluorine-containing waste brine. The process flow of the precipitation method is to add lime water (or directly add lime) to the fluorine-containing waste brine, to make the fluoride ions react with calcium ions to generate calcium fluoride solid, and then to perform standing precipitation, dehydration and other processes to separate the calcium fluoride from the remaining brine, so as to reduce the fluoride content in the brine and reduce the pollution risk.

[0004] However, the existing precipitation method for treating fluorine-containing waste brine has problems such as large equipment, long standing time during precipitation process, difficult dehydration after precipitation, unstable quality of brine after separation, and low treatment efficiency of fluorine-containing waste brine. UTILITY MODEL CONTENTS

[0005] In view of the technical problems of large equipment, difficult dehydration, unstable quality and low treatment efficiency of the existing precipitation method for treating fluorine-containing waste brine, the utility model provides a fluorine-containing waste brine treatment system, which can separate the calcium fluoride solid generated after adding calcium ions to the fluorine-containing waste brine from the liquid without the need for large-volume filtration equipment, has obvious separation effect, and occupies small area. The heat energy in the clear liquid concentration crystallization process after solid-liquid separation can be fully utilized to reduce energy consumption.

[0006] The technical scheme of the utility model is as follows:

[0007] The treatment system of fluorine-containing waste brine comprises a neutralization tank, a first feeding pipeline, a second feeding pipeline and a discharging pipeline are arranged in the neutralization tank, the first feeding pipeline is connected with a fluorine-containing waste brine tank, the second feeding pipeline is connected with a lime water tank, the discharging pipeline is connected with a cyclone, a bottom outlet of the cyclone is connected with a drying device through a feeding device, an upper outlet of the cyclone is connected with a buffer tank through a clear liquid pipeline, the buffer tank is sequentially connected with a three-effect evaporation device and a centrifugal separation device, and a liquid outlet of the centrifugal separation device is connected with the buffer tank through a concentrated salt liquid reflux pipeline.

[0008] Further, the feeding device is a spiral feeding device.

[0009] Further, an exhaust port of the drying device is connected with a washing device through a drying tail gas recovery pipeline, an exhaust port of the three-effect evaporation device is connected with the washing device through an evaporation tail gas recovery pipeline, and a tail gas discharge port is arranged on the washing device; the washing device is connected with a washing waste water reflux pipeline, the washing waste water reflux pipeline is connected with the neutralization tank, and the washing device can wash tail gas generated in the drying process of the drying device, so that hydrogen fluoride gas and other pollutants in the tail gas are absorbed into washing waste water, the washed tail gas can be discharged into the atmosphere, and pollution is avoided; and the washing waste water is refluxed to the neutralization tank through the washing waste water reflux pipeline, and is treated in a cycle.

[0010] Further, a hydrogen fluoride gas concentration detection device is arranged on the tail gas discharge port.

[0011] Further, a stirring device is arranged in the neutralization tank, and the mixed salt liquid in the neutralization tank can be stirred, so that the reaction is accelerated and the reaction is more sufficient.

[0012] Further, the second feeding pipeline is also connected with a calcium chloride solution tank, so that the lime water and the calcium chloride solution can be simultaneously fed to the neutralization tank through the second feeding pipeline, and the reaction of calcium ions and fluorine ions is more sufficient.

[0013] The treatment system of fluorine-containing waste brine has the advantages that:

[0014] The treatment system of fluorine-containing waste brine has the advantages that: the neutralization tank is connected with the cyclone through the discharging pipeline, the calcium fluoride precipitate generated in the neutralization tank is separated from the solution through the cyclone, the cyclone has small volume and small land occupation, large-volume filtering equipment is not needed, the mixed liquid is fed and discharged simultaneously during the operation of the cyclone, the solid-liquid separation can be quickly realized without waiting for standing, and the separation effect is obvious.

[0015] The utility model discloses a centrifugal separation device's liquid outlet is connected with the buffer pool through the concentrated salt liquid reflux pipeline, and the high temperature concentrated salt liquid separated through the centrifugal separation device can mix with the clear liquid separated by the subsequent batch cyclone in the buffer pool and then enter the three-effect evaporation device to concentrate and crystallize, can improve the salt concentration and temperature of the liquid in the buffer pool, fully utilize the temperature of the concentrated salt liquid after three-effect evaporation, reduce the energy consumption of three-effect evaporation device. BRIEF DESCRIPTION OF DRAWINGS

[0016] In order to make the person skilled in the art better understand the technical scheme in the utility model, the technical scheme in the embodiment of the utility model will be described clearly and completely below in conjunction with the drawings in the embodiment of the utility model, and obviously, the described embodiment is only a part of the embodiment of the utility model, not all the embodiment. Based on the embodiment in the utility model, all other embodiments obtained by the person skilled in the art without creative labor should belong to the protection scope of the utility model.

[0017] Figure 1 It is the structural schematic diagram of the treatment system of the fluorine-containing waste brine in embodiment 1.

[0018] In the drawing, 1-fluorine-containing waste brine tank, 11-first feeding pipeline, 2-lime water tank, 21-calcium chloride solution tank, 22-second feeding pipeline, 3-neutralization tank, 31-stirring device, 32-discharge pipeline, 4-cyclone, 41-screw feeder, 42-clear liquid pipeline, 5-drying device, 51-drying tail gas recovery pipeline, 6-buffer tank, 7-three-effect evaporation device, 8-centrifugal separation device, 81-concentrated salt liquid reflux pipeline, 82-evaporation tail gas recovery pipeline, 9-washing device, 91-washing wastewater reflux pipeline, 92-tail gas discharge port. DETAILED DESCRIPTION

[0019] In order to make the person skilled in the art better understand the technical scheme in the utility model, the technical scheme in the embodiment of the utility model will be described clearly and completely below in conjunction with the drawings in the embodiment of the utility model, and obviously, the described embodiment is only a part of the embodiment of the utility model, not all the embodiment. Based on the embodiment in the utility model, all other embodiments obtained by the person skilled in the art without creative labor should belong to the protection scope of the utility model.

[0020] Embodiment 1

[0021] A kind of fluorine-containing waste brine processing system, including neutralization tank 3, and stirring device 31 is provided in neutralization tank 3;First feeding pipeline 11, second feeding pipeline 22 and discharge pipeline 32 are provided in neutralization tank 3, first feeding pipeline 11 is connected with fluorine-containing waste brine tank 1, second feeding pipeline 22 is connected with lime water tank 2 and calcium chloride solution tank 21 respectively, and discharge pipeline 32 is connected with cyclone 4;

[0022] The bottom outlet of the cyclone 4 is connected with the drying device 5 through the spiral feeder 41; the exhaust outlet of the drying device 5 is connected with the washing device 9 through the drying tail gas recovery pipeline 51, and the washing device 9 is provided with a tail gas discharge port 92, and the tail gas discharge port 92 is provided with a hydrogen fluoride gas concentration detection device;

[0023] The washing device 9 is connected with the washing wastewater return pipeline 91, and the washing wastewater return pipeline 91 is connected with the neutralization tank 3; the upper outlet of the cyclone 4 is connected with the buffer tank 6 through the clear liquid pipeline 42;

[0024] The buffer tank 6 is sequentially connected with the three-effect evaporation device 7 and the centrifugal separation device 8; the exhaust outlet of the three-effect evaporation device 7 is connected with the washing device 9 through the evaporation tail gas recovery pipeline 71, and the liquid outlet of the centrifugal separation device 8 is connected with the buffer tank 6 through the concentrated salt liquid return pipeline 81.

[0025] The operation principle of the embodiment 1 is as follows:

[0026] (1) The fluorine-containing waste brine in the fluorine-containing waste brine tank 1 is introduced into the neutralization tank through the first feeding pipeline 11, the stirring device 31 is started, and the lime water in the lime water tank 2 and the calcium chloride solution in the calcium chloride solution tank 21 are introduced into the neutralization tank through the second feeding pipeline 22, so that the pH value of the fluorine-containing waste brine is adjusted to 6-8, and a mixed salt liquid containing calcium fluoride solid particles is formed;

[0027] (2) The mixed salt liquid enters the cyclone 4 through the discharge pipeline 32, the cyclone 4 separates the calcium fluoride solid in the mixed salt liquid and the supernatant, the calcium fluoride solid enters the spiral feeder 41 through the bottom outlet, and the calcium fluoride solid is transported to the drying device 5 by the spiral feeder 41; the supernatant enters the clear liquid pipeline 42 through the upper outlet, and then enters the buffer tank 6;

[0028] (3) The drying device 5 is started, the calcium fluoride solid is dried, the tail gas generated in the drying process enters the washing device 9 through the drying tail gas recovery pipeline 51, the purified tail gas after washing by the washing device 9 is discharged from the tail gas discharge port 92, the washing wastewater enters the neutralization tank 3 through the washing wastewater return pipeline 91, and is recycled; the dried calcium fluoride solid is used as a chemical raw material or sold as a commodity;

[0029] (4) the supernatant in the buffer tank 6 enters the three-effect evaporation device 7 to evaporate, concentrate and crystallize, tail gas generated in the evaporation process enters the washing device 9 for washing through the evaporation tail gas return pipeline 71, the purified tail gas after washing by the washing device 9 is discharged from the tail gas discharge port 92, and the washing waste water enters the neutralization tank 3 through the washing waste water return pipeline 91 for recycling; the concentrated solid-liquid mixture enters the centrifugal separation device 8 for solid-liquid separation, the separated liquid is high-temperature concentrated salt liquid, and the high-temperature concentrated salt liquid is returned to the buffer tank 6 through the concentrated salt liquid return pipeline 81 for recycling; and the separated solid is low-fluorine sodium chloride, the fluorine ion content of the low-fluorine sodium chloride is less than 100 ppm, and the low-fluorine sodium chloride can be treated as general solid waste.

[0030] Although the utility model has been described in detail by referring to the drawings and in combination with the preferred embodiments, the utility model is not limited thereto. Any person skilled in the art can make various equivalent modifications or replacements to the embodiments of the utility model without departing from the spirit and essence of the utility model, and these modifications or replacements shall be within the scope of the utility model. Any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the utility model, and these changes or replacements shall be within the protection scope of the utility model.

Claims

1. A system for treating fluorine-containing waste brine comprising a neutralization tank, characterized in that, The first feeding pipeline is connected with a fluorine-containing waste brine tank, the second feeding pipeline is connected with a lime water tank, and the discharge pipeline is connected with a cyclone.

2. The processing system of claim 1, wherein, The feeding device is a spiral feeder.

3. The processing system of claim 1, wherein, The exhaust port of the drying device is connected with a washing device through a drying tail gas recovery pipeline, the exhaust port of the three-effect evaporation device is connected with the washing device through an evaporation tail gas recovery pipeline, and the washing device is provided with a tail gas discharge port.

4. The processing system of claim 3, wherein, The washing device is connected with a washing waste water return pipeline, and the washing waste water return pipeline is connected with the neutralization tank.

5. The processing system of claim 1, wherein, The tail gas discharge port is provided with a hydrogen fluoride gas concentration detection device.

6. The processing system of claim 1, wherein, The neutralization tank is provided with a stirring device. The second feeding pipeline is also connected with a calcium chloride solution tank.

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