CN117800549A - Plasticizer wastewater treatment device and wastewater treatment method thereof - Google Patents

Abstract

The invention relates to a plasticizer wastewater treatment device and a wastewater treatment method thereof, wherein the plasticizer wastewater treatment device comprises a wastewater conveying pipe, a rectifying tower is communicated with the wastewater conveying pipe, a reboiling circulating pipe is arranged on the rectifying tower, a first stop valve, a first booster pump, a reboiler and a first online chromatograph are arranged on the reboiling circulating pipe, a first buffer tank, an acidification reaction kettle, a first centrifugal machine, a first concentration reaction kettle and a second buffer tank are communicated with each other through a first concentrate conveying pipe, a second concentrate conveying pipe is arranged on the first concentrate conveying pipe, a third buffer tank is communicated with the acidification reaction kettle, and an electrolytic tank, a second concentration reaction kettle, a crystallization tank and a second centrifugal machine are sequentially communicated with the second buffer tank. The invention separates organic acid and sodium sulfate from waste water, and has convenient use and wide market prospect.

Description

Plasticizer wastewater treatment device and wastewater treatment method thereof

Technical Field

The invention relates to the field of plasticizer wastewater treatment, in particular to a plasticizer wastewater treatment device and a plasticizer wastewater treatment method.

Background

The plasticizer, also called plasticizer, is a polymer material auxiliary agent widely used in industrial production, and the addition of the plasticizer into the polymer material can improve the performance of the polymer material, reduce the production cost and improve the production benefit. Is an important chemical product, is widely applied to materials such as plastic products, even cosmetics, cleaning agents and the like as an auxiliary agent, and particularly in polyvinyl chloride plastic products, and needs to be added with phthalate in order to increase the plasticity of the plastic and improve the strength of the plastic. Plasticizers commonly used at present include phthalate plasticizers, citric plasticizers, p-benzene plasticizers, cyclohexane dicarboxylic acid ester plasticizers, and the like.

In the production process of the plasticizer, organic acid anhydride or organic acid reacts with alcohol under the catalysis of sulfuric acid, and sodium hydroxide solution is adopted for neutralization after the reaction, so that a large amount of wastewater containing salt and organic matters is generated in the production process. After neutralization, most enterprises simply distill and recover part of alcohol, and then the waste water is reduced and concentrated by adopting a three-effect evaporation or vapor mechanical recompression (MVR) method to obtain high-concentration waste liquid or further dried to obtain solid waste. The waste liquid contains high-concentration organic matters mainly containing organic acid anhydride and high-concentration inorganic matters mainly containing sodium sulfate, and the most common phthalate plasticizers are taken as examples, wherein phthalic acid anhydride belongs to low-toxicity dangerous matters, has irritation to skin and mucous membrane, and can cause the risk of burning when meeting high heat, open fire or contacting with oxidizing agents; waste salt which is seriously contained with a large amount of organic acid anhydride and is obtained by the conventional method is used as toxic dangerous goods, can not be directly discharged according to the safety production regulations of enterprises, and has the risk of spontaneous combustion when being stored in the open air at high temperature in summer, so that an unstable dangerous source is caused. Furthermore, organic acid anhydride is one of important raw materials for synthesizing plasticizer, and the production cost is increased for enterprises without maximized rational utilization, so that the conventional plasticizer wastewater treatment device and the wastewater treatment method thereof have defects and cannot be reasonably popularized and applied.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides the plasticizer wastewater treatment device and the wastewater treatment method thereof, which can separate the organic acid and the sodium sulfate from the plasticizer wastewater, are convenient for further treating the wastewater residual liquid by using the existing wastewater treatment device, improve the step recovery of the organic acid and the sodium sulfate and further reduce the production cost of enterprises, and are used for overcoming the defects in the prior art.

The invention adopts the technical scheme that: the utility model provides a plasticizer effluent treatment plant, includes the waste water conveyer pipe, the intercommunication has the rectifying column on the exit end of waste water conveyer pipe, the rectifying column on be provided with the reboiling circulating pipe, the reboiling circulating pipe has set gradually first stop valve along the direction of the entry end of reboiling circulating pipe to the exit end of reboiling circulating pipe, first booster pump, reboiler and first on-line densimeter, reboiling circulating pipe intercommunication between first booster pump and the reboiler has the entry end of first buffer tank, the intercommunication has the acidizing reation kettle on the exit end of first buffer tank, the below intercommunication of acidizing reation kettle has the entry end of first centrifuge, the intercommunication has first concentrated reation kettle on the exit end of first centrifuge, the intercommunication has the second buffer tank on the exit end of first concentrated reation kettle, be linked together through first concentrate conveyer pipe between second buffer tank and the first concentrated reation kettle, be provided with the second concentrate conveyer pipe on the exit end of second concentrate conveyer pipe, the intercommunication has the third buffer tank, third buffer tank is linked together with the entry end of acidizing reation kettle, the exit end of second buffer tank in proper order, the second concentrate reation tank has crystallization tank and second reation kettle.

Preferably, the rectifying tower is provided with a first liquefied water conveying pipe, the first liquefied water conveying pipe is provided with a heat source channel of the second heat exchanger, the outlet end of the first liquefied water conveying pipe is provided with an alkali liquor preparation tank, the first liquefied water conveying pipe between the alkali liquor preparation tank and the second heat exchanger is provided with a second liquefied water conveying pipe, the first liquefied water conveying pipe between the second liquefied water conveying pipe and the alkali liquor preparation tank and the second liquefied water conveying pipe are respectively provided with a first regulating valve, the alkali liquor preparation tank is provided with a stirring device, and the alkali liquor preparation tank, the acidification reaction kettle and the first concentration reaction kettle are respectively provided with an acidimeter correspondingly.

Preferably, the rectifying tower comprises a tower body, a first packing layer and a second packing layer are sequentially arranged in the tower body from top to bottom, the tower body between the first packing layer and the second packing layer is communicated with a waste water conveying pipe, a cold source channel of a first heat exchanger is arranged on the waste water conveying pipe, an inlet end of a heat source channel of the first heat exchanger is communicated with the top end of the tower body, a gas-liquid separation tank is communicated with an outlet end of the heat source channel of the first heat exchanger, a liquid phase outlet end of the gas-liquid separation tank is communicated with the tower body above the first packing layer through a crude alcohol return pipe, a second regulating valve is arranged on the crude alcohol return pipe, a crude alcohol conveying pipe is arranged on the crude alcohol return pipe between the second regulating valve and the gas-liquid separation tank, and a third regulating valve is arranged on the crude alcohol conveying pipe.

Preferably, the first concentrated solution conveying pipe is provided with a second booster pump, a fourth regulating valve and a first one-way valve in sequence along the direction from the first concentrated reaction kettle to the second buffer tank, the electrolytic tank and the second buffer tank are communicated through a third concentrated solution conveying pipe, the third concentrated solution conveying pipe is provided with a third booster pump and a fifth regulating valve in sequence along the direction from the second buffer tank to the electrolytic tank, the third concentrated solution conveying pipe between the third booster pump and the fourth regulating valve is communicated with the first one-way valve and the first concentrated solution conveying pipe between the second buffer tank through a concentrated solution circulating pipe, the concentrated solution circulating pipe is provided with a second stop valve and a second one-way valve in sequence along the third concentrated solution conveying pipe to the first concentrated solution conveying pipe, the first concentrated solution conveying pipe between the second booster pump and the fourth regulating valve is communicated with the inlet end of the second concentrated solution conveying pipe, and the second concentrated solution conveying pipe is provided with a sixth regulating valve.

Preferably, the liquid phase outlet end of the second centrifugal machine is communicated with a first centrifugal liquid conveying pipe, a fifth buffer tank is arranged on the first centrifugal liquid conveying pipe, the fifth buffer tank is communicated with the second concentration reaction kettle through a second centrifugal liquid conveying pipe, a fifth booster pump and a second liquid flow sensor are sequentially arranged on the second centrifugal liquid conveying pipe along the direction from the fifth buffer tank to the second concentration reaction kettle, a third centrifugal liquid conveying pipe is arranged on the second centrifugal liquid conveying pipe between the fifth buffer tank and the fifth booster pump, and an eighth regulating valve is respectively arranged on the second centrifugal liquid conveying pipe between the third centrifugal liquid conveying pipe and the second liquid flow sensor and on the third centrifugal liquid conveying pipe.

Preferably, the top of a cleaning tank is communicated below the first centrifugal machine, a third centrifugal machine is arranged above the cleaning tank, the inlet end of the third centrifugal machine is communicated with the bottom of the cleaning tank through a cleaning conveying pipe, a third stop valve, a fourth booster pump and a second online densimeter are arranged on the cleaning conveying pipe, a first solid material conveying pipe and a second solid material conveying pipe are arranged on the solid phase outlet end of the third centrifugal machine, the third centrifugal machine is communicated with the cleaning tank through the second solid material conveying pipe, a fourth stop valve is respectively arranged on the first solid material conveying pipe and the second solid material conveying pipe, the first centrifugal machine is communicated with the first concentrating reaction kettle through a fourth centrifugal liquid conveying pipe, a seventh buffer tank is arranged on the fourth centrifugal liquid conveying pipe, and the liquid phase outlet end of the third centrifugal machine is communicated with the seventh buffer tank.

Preferably, the gas phase outlet end of the second concentration reaction kettle is sequentially communicated with a third liquefied water conveying pipe and a sixth buffer tank, the third liquefied water conveying pipe is provided with a third heat exchanger, the sixth buffer tank is communicated with the cleaning tank through a fourth liquefied water conveying pipe, the fourth liquefied water conveying pipe is provided with a fifth liquefied water conveying pipe, and the fourth liquefied water conveying pipe and the fifth liquefied water conveying pipe between the fifth liquefied water conveying pipe and the cleaning tank are respectively provided with a ninth regulating valve.

The wastewater treatment method of the plasticizer wastewater treatment device is characterized by comprising the following steps:

s5: the acidification reaction kettle receives the wastewater conveyed by the first buffer tank and reaches a preset liquid level, and then a preset amount of sulfuric acid is added into the acidification reaction kettle to acidify the wastewater to form a strong acid environment; then continuously stirring, conveying to a first centrifugal machine for solid-liquid separation after stirring for a preset time, conveying the liquid phase component to a first concentration reaction kettle through a liquid phase component outlet of the first centrifugal machine, and discharging the solid phase component through a solid phase component outlet of the first centrifugal machine;

s6: the liquid entering the first concentration reaction kettle can be started after reaching a preset liquid level, the first concentration reaction kettle is used for carrying out primary concentration on the liquid entering the first concentration reaction kettle to form an acidic concentrated solution, and the acidic concentrated solution is divided into two parts: part of the liquid is conveyed to a third buffer tank, and the rest of the liquid is conveyed to a second buffer tank for temporary storage;

s7: adding sodium hydroxide alkali liquor into the second buffer tank until the value fed back by the acidometer on the second buffer tank is neutral, so as to form neutral concentrated solution; delivering part of neutral concentrated solution to an electrolytic tank to electrolyze and remove residual organic matters contained in the period to form residual liquid after electrolysis;

S8: delivering the electrolyzed residual liquid to a second concentration reaction kettle for secondary concentration to form secondary concentrated liquid;

s9: and conveying the secondary concentrated solution to one of crystallization tanks to be connected with the secondary concentrated solution, adding seed crystals into the crystallization tank after conveying, crystallizing sodium sulfate, fully standing to complete the crystallization process, forming sodium sulfate crystals and residual liquid after crystallization, conveying the sodium sulfate crystals to a second centrifugal machine for solid-liquid separation, discharging the sodium sulfate crystals from a solid phase outlet of the second centrifugal machine, and discharging the residual liquid after crystallization from a liquid phase outlet of the second centrifugal machine.

The invention has the beneficial effects that: firstly, the invention realizes the separation of the alcohol phase contained in the plasticizer wastewater and the recovery as crude alcohol, and effectively recovers the alcohol raw material produced as plasticizer;

in addition, the separation of the organic acid as the solid from the rectification residual liquid is realized through gradual separation, the recovery of the organic acid reduces the material loss of the organic acid, simultaneously reduces the content of the organic matters contained in the solid after concentration and crystallization, and reduces the dangerous waste grade of the solid; after the alcohol phase and the organic acid are separated, a small amount of organic matters are still contained in the residual liquid, and the organic matters contained in the residual liquid are removed through electrolysis in an electrolytic tank, so that the organic matters in the residual liquid which is conveyed to a second concentration reaction kettle for secondary concentration are approximately zero; greatly reduces the content of organic matters in the residual liquid, and ensures that the residual liquid is easier to treat.

Secondly, the invention forms secondary concentrated solution after secondary concentration through the second concentration reaction kettle, and conveys the secondary concentrated solution into the crystallization tank, and crystal seeds are added into the crystallization tank to crystallize sodium sulfate, thereby realizing the recovery of sodium sulfate.

Finally, the invention carries out primary concentration through the first concentration reaction kettle to form acidic concentrated solution, and part of the formed acidic concentrated solution is conveyed to the third buffer tank for temporary storage, so that the acidic concentrated solution is used as one of sources of acidic medium in the acidification reaction kettle, and the material consumption for treating plasticizer wastewater is saved.

The invention has the advantages of simple structure, convenient operation, ingenious design, great improvement of working efficiency, good social and economic benefits and easy popularization and use.

Drawings

Fig. 1 is a schematic structural view of the present invention.

Fig. 2 is an enlarged partial schematic view of detail a of fig. 1.

Detailed Description

Example 1: as shown in fig. 1 and 2, a plasticizer wastewater treatment device comprises a wastewater conveying pipe 1, wherein a rectifying tower is communicated with the outlet end of the wastewater conveying pipe 1, a reboiling circulating pipe 2 is arranged on the rectifying tower, the rectifying tower comprises a tower body 25, a first packing layer 26 and a second packing layer 27 are sequentially arranged in the tower body 25 from top to bottom, the tower body 25 between the first packing layer 26 and the second packing layer 27 is communicated with the wastewater conveying pipe 1, a cold source channel of a first heat exchanger 28 is arranged on the wastewater conveying pipe 1, the inlet end of the heat source channel of the first heat exchanger 28 is communicated with the top end of the tower body 25, a gas-liquid separation tank 29 is communicated with the outlet end of the heat source channel of the first heat exchanger 28, the liquid phase outlet end of the gas-liquid separation tank 29 is communicated with the tower body 25 above the first packing layer 26 through a crude alcohol return pipe 30, a second regulating valve 31 is arranged on the crude alcohol return pipe 30, a crude alcohol conveying pipe 32 is arranged on the crude alcohol return pipe 30 between the second regulating valve 31 and the gas-liquid separation tank 29, and a third regulating valve 33 is arranged on the crude alcohol conveying pipe 32. The inlet end of the reboiling circulating pipe 2 is positioned at the bottom end of the tower body 25, and the outlet end of the reboiling circulating pipe 2 is positioned on the tower body 25 between the inlet end of the reboiling circulating pipe 2 and the second packing layer 27; the reboiling circulation pipe 2 is sequentially provided with a first stop valve 3, a first booster pump 4, a reboiler 5, a temperature sensor 74 and a first online densimeter 6 along the direction from the inlet end of the reboiling circulation pipe 2 to the outlet end of the reboiling circulation pipe 2, the reboiling circulation pipe 2 between the first booster pump 4 and the reboiler 5 is communicated with the inlet end of a first buffer tank 7, the reboiling circulation pipe 2 is communicated with the first buffer tank 7 through a fifth concentrated solution conveying pipe 76, and a tenth regulating valve 75 is respectively arranged on the reboiling circulation pipe 2 between the fifth concentrated solution conveying pipe 76 and the reboiler 5 and on the fifth concentrated solution conveying pipe 76; an acidification reaction kettle 8 is communicated with the outlet end of the first buffer tank 7, the acidification reaction kettle 8 is communicated with the first buffer tank 7 through a sixth concentrated solution conveying pipe 77, and a sixth booster pump 78 is arranged on the sixth concentrated solution conveying pipe 77; the below intercommunication of acidizing reation kettle 8 has the entry end of first centrifuge 9, the liquid phase outlet end intercommunication of first centrifuge 9 has first concentrated reation kettle 10, the intercommunication has second buffer tank 11 on the exit end of first concentrated reation kettle 10, be linked together through first concentrate conveyer pipe 12 between second buffer tank 11 and the first concentrated reation kettle 10, be provided with second concentrate conveyer pipe 13 on the first concentrate conveyer pipe 12, the intercommunication has third buffer tank 14 on the exit end of second concentrate conveyer pipe 13, third buffer tank 14 is linked together with acidizing reation kettle 8, the intercommunication has electrolysis trough 15 on the exit end of second buffer tank 11 in proper order, second concentrated reation kettle 16, crystallization tank 17 and second centrifuge 18.

The acidification reaction kettle 8, the first concentration reaction kettle 10 and the second concentration reaction kettle 16 are respectively provided with a pressure sensor 72, a temperature sensor 74 and a liquid level sensor 73. Acidizing reactor 8, first concentrated reation kettle 10 and second buffer tank 11 are provided with acidimeter 24 respectively.

The acidification reaction kettles 8, the second concentration reaction kettles 16 and the crystallization tanks 17 are all of a plurality of numbers, the acidification reaction kettles 8 are connected in parallel, the second concentration reaction kettles 16 are connected in parallel, and the crystallization tanks 17 are connected in parallel.

Before the formal driving operation stage, a pre-operation process is required to be performed, wherein the pre-operation process is divided into two stages, namely a first pre-operation process stage and a second pre-operation process stage. The first pre-run process phase comprises the following steps, S1: the waste water generated in the plasticizer production system is conveyed from the waste water conveying pipe 1 to the inner cavity of the tower body 25 between the first packing layer 26 and the second packing layer 27 through the cold source channel of the first heat exchanger 28, and flows to the bottom of the tower body 25 through the second packing layer 27 due to the gravity.

S2: after the medium at the bottom of the tower body 25 enters the inlet end of the reboiling circulating pipe 2 and is pressurized by the first booster pump 4, the wastewater entering the reboiling circulating pipe 2 moves along the direction from the inlet end of the reboiling circulating pipe 2 to the outlet end of the reboiling circulating pipe 2, the mixed liquid density is heated by the reboiler 5, the temperature is fed back by the first on-line densimeter 6 and fed back by the temperature sensor 74, a heat source is formed from the newly returned bottom of the tower body 25, a large amount of alcohol components and water components form a gas phase part to flow to the top of the tower body 25 along the second packing layer 27, during the countercurrent heat exchange between rising steam and the wastewater in the inner cavity of the tower body 25 between the first packing layer 26 and the second packing layer 27, the rising steam part is cooled and the alcohol components contained in the returned to the tower bottom wastewater are evaporated and flow to the tower body 25 along with the rising steam through the first packing layer 26; the steam is a gaseous mixture of alcohol and water.

S3: the steam enters a heat source channel of the first heat exchanger 28 through the tower body 25 and exchanges heat with the wastewater which enters a cold source channel of the first heat exchanger 28 and is conveyed by the wastewater conveying pipe 1, the steam passing through the heat source channel of the first heat exchanger 28 is cooled, and the alcohol phase and the water phase are liquefied and a small amount of noncondensable gas is cooled; the wastewater fed through the wastewater feed pipe 1 of the cold source channel of the first heat exchanger 28 is heated and then fed into the inner space of the tower body 25. The liquefied gas phase component enters a gas-liquid separation tank 29, noncondensable gas is discharged from the top of the gas-liquid separation tank 29 and is sent to an industrial torch for combustion treatment, the liquid phase component is a liquid mixture of alcohol and water, and crude alcohol is formed at the bottom of the gas-liquid separation tank 29 in an enriched manner; a part of the crude alcohol is refluxed into the inner cavity of the tower body 25 above the first packing layer 26 through the crude alcohol reflux pipe 30 as another cold source, and continuously descends under the action of gravity and the steam continuously ascends through the first packing layer 26 carries out countercurrent heat exchange, the water phase component in the steam is liquefied and then descends to the bottom of the tower body 25, the alcohol phase in the liquid crude alcohol entering the inner cavity of the tower body 25 is evaporated and continuously ascends, and the water phase continuously descends along the first packing layer 26 to the bottom of the tower body 25. And the other part of crude alcohol is conveyed to a crude alcohol rectification section through a crude alcohol conveying pipe 32 to carry out crude alcohol rectification, so that an alcohol phase is recovered, and the cost is saved. After the value fed back by the first on-line densitometer 6 is continuously stabilized to a preset range, the first pre-operation process stage can be ended.

The purpose of the first pre-operation is to form a liquid raffinate with low alcohol content at the bottom of the tower body 25, and the second stage pre-operation can be performed on the basis of the first stage pre-operation, where the second pre-operation stage includes steps S1 to S3 of the first pre-operation stage, but the difference between step S2 of the second pre-operation stage and step S2 of the first pre-operation stage is that: the wastewater entering the reboiling circulation pipe 2 does not move all along the direction from the inlet end of the reboiling circulation pipe 2 to the outlet end of the reboiling circulation pipe 2; instead, a part of the wastewater entering the reboiling circulating pipe 2 moves along the direction from the inlet end of the reboiling circulating pipe 2 to the outlet end of the reboiling circulating pipe 2, and during the part, the heat source is formed by heating through the reboiler 5, feeding back the liquid component through the first online densitometer 6 and feeding back the temperature through the temperature sensor 74, and then the heat source is formed from the bottom of the tower body 25 which is newly returned to; the other part is fed to the first buffer tank 7 through the fifth concentrate feed pipe 76, and the distribution ratio of the part returned to the column 25 during the period to the liquid fed to the first buffer tank 7 is comprehensively adjusted by adjusting the opening of the tenth adjusting valve 75 installed on the reboiling circulation pipe 2 between the fifth concentrate feed pipe 76 and the reboiler 5 and the opening of the tenth adjusting valve 75 installed on the fifth concentrate feed pipe 76. Since the liquid raffinate with low alcohol content is formed at the bottom of the tower body 25 during the first pre-operation, in the step S2, the waste water continuously supplied to the inner cavity of the tower body 25 through the waste water supply pipe 1 is distilled out of the alcohol phase contained in the waste water in the second packing layer 27 and the process of countercurrent heat exchange of the steam generated at the bottom of the tower body 25, the raffinate falling to the bottom of the tower body 25 and the liquid refluxed at the bottom of the tower body 25 are mixed to form the waste water entering the reboiling circulation pipe 2, and the alcohol phase content of the waste water is low.

On the basis of the first-stage pre-operation process, the second-stage pre-operation process is sequentially added with the following steps after the step S3, and the step S4 is as follows: continuously entering the first buffer tank 7 for temporary storage through the fifth concentrated solution conveying pipe 76, and conveying the first buffer tank 7 to the acidification reaction kettle 8 to the preset liquid level of the acidification reaction kettle 8 through the sixth concentrated solution conveying pipe 77 under the pressurization of the sixth booster pump 78 according to the requirements of the corresponding acidification reaction kettle 8.

S5: the acidification reaction kettle 8 receives the wastewater conveyed by the first buffer tank 7 and reaches a preset liquid level, and then a preset amount of sulfuric acid is added into the acidification reaction kettle 8 to acidify the wastewater to form a strong acid environment, wherein the PH value is not more than 2; continuously stirring, wherein in the process, after the waste water is acidified, organic acid components in the waste water form organic acid solids which are continuously separated out to form suspension, after stirring for a preset time, the suspension is conveyed to a first centrifugal machine 9 for solid-liquid separation, liquid phase components are conveyed to a first concentration reaction kettle 10 through a liquid phase component outlet of the first centrifugal machine 9, and solid phase components are discharged through a solid phase component outlet of the first centrifugal machine 9; in this step, the organic acid component forming a solid phase is separated and recovered for reuse after being discharged through the solid phase component outlet of the first centrifuge 9.

S6: the liquid entering the first concentration reaction kettle 10 can be started after reaching a preset liquid level, the first concentration reaction kettle 10 carries out primary concentration on the liquid entering the first concentration reaction kettle 10 to form an acidic concentrated solution, and the acidic concentrated solution is divided into two parts: part of the liquid is sent to the third buffer tank 14, and the rest of the liquid is sent to the second buffer tank 11 for temporary storage.

S7: adding sodium hydroxide alkali liquor into the second buffer tank 11 until the value fed back by the acidometer 24 on the second buffer tank 11 is neutral, so as to form neutral concentrated solution; part of the neutral concentrate is fed to the electrolytic tank 15 for electrolytic removal of the remaining organic matter contained in the process, to form a post-electrolysis raffinate.

S8: and conveying the electrolyzed residual liquid to a second concentration reaction kettle 16 for secondary concentration to form secondary concentrated liquid.

S9: and (3) conveying the secondary concentrated solution to one of crystallization tanks 17 to be connected with the secondary concentrated solution, adding seed crystals into the crystallization tank 17 after conveying, crystallizing sodium sulfate, fully standing to complete the crystallization process, forming sodium sulfate crystals and residual liquid after crystallization, conveying the sodium sulfate crystals into a second centrifuge 18 for solid-liquid separation, discharging the sodium sulfate crystals from a solid phase outlet of the second centrifuge 18, and discharging the residual liquid after crystallization from a liquid phase outlet of the second centrifuge 18.

After the above steps are completed and the third buffer tank 14 reaches the preset level, the second pre-operation process stage is completed, and the production steps of the formal driving operation stage include steps S1 to S9 of the second pre-operation stage, but the step S5 of the formal driving operation stage is different from the step S5 of the second pre-operation stage in that: in step S5 of the final operation stage, a part of the source of the acidic medium in the acidification reactor 8 is derived from sulfuric acid added from the outside, and the other part is derived from the concentrated acidic concentrate stored in the third buffer tank 14.

By example 1, it was achieved that the alcohol phase contained in the plasticizer wastewater was separated and recovered as crude alcohol, effectively recovering the alcohol raw material produced as plasticizer; in addition, the separation of the organic acid as solid from the rectification residual liquid is realized through gradual separation, the recovery of the organic acid realizes the reduction of the material loss of the organic acid, and the content of the organic acid contained in the solid after concentration and crystallization also reduces the dangerous waste grade of the solid; after the alcohol phase and the organic acid are separated, the residual liquid still contains a small amount of organic matters, and the residual organic matters contained in the electrolytic removal period are removed through the electrolytic tank 15, so that the organic matters in the residual liquid which is conveyed to the second concentration reaction kettle 16 for secondary concentration are approximately zero; the content of organic matters in the residual liquid is greatly reduced, so that the residual liquid is easier to treat; then, the second concentration reaction kettle 16 is used for carrying out secondary concentration to form crystallization residual liquid, the crystallization residual liquid is conveyed into a crystallization tank 17, and crystal seeds are added into the crystallization tank for crystallizing sodium sulfate, so that the recovery of sodium sulfate is realized; finally, the acid concentrated solution is formed by once concentration in the first concentration reaction kettle 10, and part of the formed acid concentrated solution is conveyed to the third buffer tank 14 for temporary storage, so that the acid concentrated solution is used as one of sources of acid mediums in the acidification reaction kettle 8, and the material consumption for treating plasticizer wastewater is saved.

Embodiment 2, as shown in fig. 1 and 2, the difference from embodiment 1 is that, in embodiment 2, a first liquefied water delivery pipe 19 is provided on the rectifying tower on the basis of embodiment 1, a heat source channel of a second heat exchanger 20 is provided on the first liquefied water delivery pipe 19, an alkali liquor preparation tank 21 is provided on an outlet end of the first liquefied water delivery pipe 19, a second liquefied water delivery pipe 22 is provided on the first liquefied water delivery pipe 19 between the alkali liquor preparation tank 21 and the second heat exchanger 20, a first regulating valve 23 is provided on the first liquefied water delivery pipe 19 and the second liquefied water delivery pipe 22 between the second liquefied water delivery pipe 22 and the alkali liquor preparation tank 21, respectively, the bottom of the alkali liquor preparation tank 21 is communicated with the top of the second buffer tank 11, and a first regulating valve 23 is also installed on a communicating pipe between the alkali liquor preparation tank 21 and the second buffer tank 11; the alkali liquor preparation tank 21 is provided with a stirring device, and the alkali liquor preparation tank 21 is also provided with an acidometer 24.

In steps S1 to S3 in embodiment 1, the high concentration water vapor generated in the wastewater generated in the plasticizer production system during the rectification in the rectification column is transported outwards through the first liquefied water transport pipe 19 in embodiment 2, and is subjected to heat exchange by the heat source channel of the second heat exchanger 20 and the continuously transported cold source in the cold source channel of the second heat exchanger 20, the water vapor is liquefied through the heat source channel of the second heat exchanger 20 to form liquefied water, and the liquefied water is discharged from the outlet end of the heat source channel of the second heat exchanger 20 and moves continuously along the first liquefied water transport pipe 19 in the direction of the lye preparation tank 21, wherein a part of the liquefied water enters the lye preparation tank 21, and the other part of the liquefied water is transported to the biochemical treatment device through the second liquefied water transport pipe 22 for treatment.

The liquefied water entering the lye preparation tank 21 is used as a solvent for lye preparation, a preset amount of sodium hydroxide is added according to the liquid level feedback on the lye preparation tank 21 to form sodium hydroxide solution with preset concentration, and the acidity value of the sodium hydroxide solution is fed back by an acidometer 24 arranged on the lye preparation tank 21 to be used as the source of the sodium hydroxide lye required by the second buffer tank 11 in step S7 in the embodiment 1.

By comparing example 2 with example 1, example 2 uses the liquefied water formed after the liquefaction of the water vapor discharged from the rectifying column as a source of sodium hydroxide lye required for the second buffer tank 11 in step S7 in example 1. The liquefied water formed after the water vapor discharged from the rectifying tower is liquefied still contains a small amount of alcohol phase components, and is used as a source of sodium hydroxide lye required by the second buffer tank 11 in the step S7, the sodium hydroxide lye provided by the second buffer tank 11 is added into the second buffer tank 11 to be neutral, and a neutral concentrated solution is formed; after being sent to the electrolytic tank 15 for electrolysis, the additional alcohol phase component carried by the part of the solvent is decomposed into inorganic components after the electrolytic tank 15 is subjected to the electrolysis process. Although a part of electricity is consumed, the addition of an external liquid phase medium in the wastewater treatment process is reduced, and the total amount of the wastewater treated as a whole is reduced.

Embodiment 3, as shown in fig. 1 and fig. 2, differs from embodiment 1 in that embodiment 4 is that, on the basis of embodiment 1, the third buffer tank 14 is communicated with the acidification reaction kettle 8 through a fourth concentrated solution conveying pipe 44, a sulfuric acid storage tank 45 is communicated above the acidification reaction kettle 8, the sulfuric acid storage tank 45 is communicated with the acidification reaction kettle 8 through a sulfuric acid conveying pipe 46, and the sulfuric acid conveying pipe 46 and the fourth concentrated solution conveying pipe 44 are respectively provided with a first liquid flow sensor 47 and a seventh regulating valve 48.

In addition, in the step S5 of the main operation stage, the difference from example 1 is that part of sulfuric acid, which is derived from the outside, of the acidic medium in the acidification reactor 8 is supplied from the sulfuric acid storage tank 45 and is transported via the sulfuric acid transport pipe 46, and the volume parameter of the sulfuric acid fed to the acidification reactor 8 via the sulfuric acid transport pipe 46 is fed back by the first liquid flow sensor 47 mounted on the sulfuric acid transport pipe 46; the acidic concentrate which originates from the third buffer tank 14 and is fed to the acidification reactor 8 is fed via a fourth concentrate feed pipe 44, and the volume parameter of the acidic concentrate fed to the acidification reactor 8 via the fourth concentrate feed pipe 44 is fed back by a first liquid flow sensor 47 mounted on the fourth concentrate feed pipe 44.

By comparing example 3 with example 1, example 3 facilitates feedback of the volume parameter of sulfuric acid fed from the sulfuric acid tank 45 to the acidification reactor 8 by providing the sulfuric acid tank 45, the sulfuric acid feed pipe 46 and the first liquid flow sensor 47 provided by the sulfuric acid feed pipe 46; the feedback of the volume parameters of the acidic concentrate fed by the third buffer tank 14 to the acidification reactor 8 is facilitated by the provision of the fourth concentrate feed conduit 44 and the first liquid flow sensor 47 mounted on the fourth concentrate feed conduit 44.

Embodiment 4 is different from embodiment 3 in that, as shown in fig. 1 and 2, the first concentrated solution conveying pipe 12 is sequentially provided with a second booster pump 34, a fourth regulating valve 35 and a first check valve 36 along the direction from the first concentrated reaction kettle 10 to the second buffer tank 11 on the basis of embodiment 3, the electrolytic tank 15 and the second buffer tank 11 are communicated through a third concentrated solution conveying pipe 37, the third concentrated solution conveying pipe 37 is sequentially provided with a third booster pump 38 and a fifth regulating valve 39 along the direction from the second buffer tank 11 to the electrolytic tank 15, a third concentrated solution conveying pipe 37 between the third booster pump 38 and the fourth regulating valve 35 is communicated with the first concentrated solution circulating pipe 12 between the first check valve 36 and the second buffer tank 11 through a concentrated solution 40, the concentrated solution 40 is sequentially provided with a second stop valve 41 and a second check valve 42 along the third concentrated solution conveying pipe 37 to the first concentrated solution conveying pipe 12, the first concentrated solution conveying pipe 12 between the second booster pump 34 and the fourth regulating valve 35 is communicated with the second concentrated solution circulating pipe 13 at the second inlet end of the second booster pump 13.

Also differing from example 3 is step S6: the first concentration reaction kettle 10 performs primary concentration on the liquid entering the first concentration reaction kettle 10 to form an acidic concentrated solution, and the acidic concentrated solution is divided into two parts: a part of the acidic concentrated solution is sent to the third buffer tank 14, and the part of the acidic concentrated solution sent to the third buffer tank 14 is sent through the first concentrated solution conveying pipe 12 and the second concentrated solution conveying pipe 13, and is pressurized by the second booster pump 34 on the first concentrated solution conveying pipe 12; the rest part is conveyed to the second buffer tank 11 for temporary storage, and the part conveyed to the second buffer tank 11 is conveyed through the first concentrated solution conveying pipe 12 after being pressurized by the second booster pump 34; the ratio between the acidic concentrate fed to the second buffer tank 11 and the acidic concentrate fed to the third buffer tank 14 is comprehensively adjusted by adjusting the opening of the fourth adjusting valve 35 attached to the first concentrate feed pipe 12 and the opening of the sixth adjusting valve 43 attached to the second concentrate feed pipe 13. It should be noted that, in the step S5 of the embodiment 3, the liquid phase component separated by the first centrifuge 9 is sent to the first concentration reaction kettle 10, and part of the organic acid still dissolves in the liquid phase component, so that during the concentration of the liquid phase component by the first concentration reaction kettle 10, part of the organic acid is separated out to form solid precipitate along with the decrease of the volume of the liquid phase component, that is, the acidic concentrated solution of the first concentration reaction kettle 10 sent to the third buffer tank 14 and the second buffer tank 11 is suspension; the organic acid precipitate contained in the acidic concentrate fed to the third buffer tank 14 and fed to the acidification reactor 8 is collected again during acidification, thereby improving the recovery rate of the organic acid. Further, the method comprises the steps of; the inlet end of the third concentrated solution conveying pipe 37 is positioned above the bottom end of the second buffer tank 11, a drain pipe is arranged on the bottom end of the second buffer tank 11, and a drain stop valve is arranged on the drain pipe. The organic acid in solid form contained in the acidic concentrate fed to the second buffer tank 11 is concentrated at the bottom of the inner cavity of the second buffer tank 11, the blowdown stop valve is opened periodically to discharge the acidic concentrate containing the organic acid from the second buffer tank 11 by using the blowdown pipe, and the organic acid precipitate is separated to obtain the organic acid to the greatest extent, so that the amount of organic matters decomposed by the electrolytic tank 15 is reduced.

In addition, unlike in example 3, the value fed back by the acidimeter 24 for adding sodium hydroxide lye to the second buffer tank 11 in step S7 is neutral, and in the process of forming a neutral concentrated solution, the third booster pump 38 and the second stop valve 41 need to be opened and the fifth regulating valve 39 needs to be closed in the process of receiving sodium hydroxide lye in the second buffer tank 11, and in the process of receiving sodium hydroxide lye in the second buffer tank 11, the acidic concentrated solution which enters the concentrated solution circulation pipe 40 through the third concentrated solution delivery pipe 37 is pressurized by the third booster pump 38, and thus the acidic concentrated solution temporarily stored in the second buffer tank 11 sequentially passes through the third concentrated solution delivery pipe 37 and the concentrated solution circulation pipe 40, and finally flows back to the second buffer tank 11 to form a circulation.

By comparing example 4 with example 3, example 3 facilitates adjusting the ratio of the acidic concentrate to be fed to the second buffer tank 11 and the third buffer tank 14 by providing the first concentrate feed pipe 12 and the second concentrate feed pipe 13, and installing the fourth adjusting valve 35 on the first concentrate feed pipe 12, and installing the sixth adjusting valve 43 on the second concentrate feed pipe 13; in addition, by providing the concentrate circulation pipe 40 and the third concentrate delivery pipe 37, and installing the third booster pump 38 in the third concentrate delivery pipe 37, the function of flow guidance provided by the first check valve 36 installed in the first concentrate delivery pipe 12 and the second check valve 42 installed in the concentrate circulation pipe 40 is utilized. In the process that the second buffer tank 11 receives the sodium hydroxide lye, the acid concentrated solution in the second buffer tank 11 flows back to the second buffer tank 11 through the concentrated solution circulating pipe 40 after the third booster pump 38 is driven to form circulation, so that the acid concentrated solution in the second buffer tank 11 and the sodium hydroxide lye entering the second buffer tank 11 can be quickly and evenly mixed, and the technical problem of excessive addition of the sodium hydroxide lye is reduced.

Embodiment 5 is different from embodiment 1 in that, as shown in fig. 1 and 2, in embodiment 5, a first centrifugal liquid delivery pipe 49 is connected to the liquid phase outlet end of the second centrifuge 18 described above based on embodiment 1, a fifth buffer tank 50 is provided on the first centrifugal liquid delivery pipe 49, the fifth buffer tank 50 and the second concentrating reaction kettle 16 are connected through a second centrifugal liquid delivery pipe 51, a fifth booster pump 52 and a second liquid flow sensor 53 are sequentially provided on the second centrifugal liquid delivery pipe 51 along the direction from the fifth buffer tank 50 to the second concentrating reaction kettle 16, a third centrifugal liquid delivery pipe 54 is provided on the second centrifugal liquid delivery pipe 51 between the fifth buffer tank 50 and the fifth booster pump 52, and an eighth regulating valve 55 is provided on each of the second centrifugal liquid delivery pipe 51 between the third centrifugal liquid delivery pipe 54 and the second liquid flow sensor 53 and the third centrifugal liquid delivery pipe 54.

In addition, the difference from example 1 is that in step S9, after the crystallized residual liquid is discharged from the liquid phase outlet of the second centrifuge 18, the crystallized residual liquid is transferred to the fifth buffer tank 50 for temporary storage; part of the crystallized residual liquid in the fifth buffer tank 50 is discharged to a drying furnace through a third centrifugate conveying pipe 54 to be dried and collected into residual inorganic solid, and the other part of the crystallized residual liquid is conveyed to the second concentration reaction kettle 16 through a second centrifugate conveying pipe 51 and is mixed with the residual liquid after entering the second concentration reaction kettle 16 for electrolysis, and secondary concentration is carried out to form secondary concentrated liquid. And is fed as a secondary concentrate to the crystallization tank 17 as a secondary concentrate to be crystallized by adding seed crystals.

By comparing example 5 with example 1, example 5 improves the recovery rate of sodium sulfate by re-transporting part of the crystallized raffinate back to the second concentration reaction vessel 16, mixing with the raffinate after electrolysis in the second concentration reaction vessel 16, performing secondary concentration to form a secondary concentrated solution, transporting the secondary concentrated solution to the crystallization tank 17, adding seed crystals for crystallization, and since the crystallized raffinate discharged from the liquid phase outlet of the second centrifuge 18 contains sodium sulfate solute with high concentration.

Embodiment 6, as shown in fig. 1 and 2, the difference from embodiment 1 is that in embodiment 6, the top of the cleaning tank 59 is connected below the first centrifuge 9 on the basis of embodiment 1, a stirring device is disposed on the cleaning tank 59, a third centrifuge 60 is disposed above the cleaning tank 59, an inlet end of the third centrifuge 60 is connected to the bottom of the cleaning tank 59 through a cleaning delivery pipe 61, a third stop valve 62, a fourth booster pump 63 and a second on-line densitometer 64 are disposed on the cleaning delivery pipe 61, a first solid material delivery pipe 65 and a second solid material delivery pipe 66 are disposed on a solid phase outlet end of the third centrifuge 60, the third centrifuge 60 is connected to the cleaning tank 59 through the second solid material delivery pipe 66, a fourth stop valve 67 is disposed on the first centrifuge 65 and the second solid material delivery pipe 66, the first centrifuge 9 is connected to the first concentrating reaction kettle 10 through a fourth centrifugal liquid delivery pipe 79, a seventh buffer tank 71 is disposed on the fourth centrifugal liquid delivery pipe 79, and a liquid phase outlet end of the third centrifuge 60 is connected to the seventh buffer tank 71. The gas phase outlet end of the second concentration reaction kettle 16 is sequentially communicated with a third liquefied water conveying pipe 56 and a sixth buffer tank 57, the third liquefied water conveying pipe 56 is provided with a third heat exchanger 58, the sixth buffer tank 57 is communicated with a cleaning tank 59 through a fourth liquefied water conveying pipe 68, the fourth liquefied water conveying pipe 68 is provided with a fifth liquefied water conveying pipe 69, and the fourth liquefied water conveying pipe 68 and the fifth liquefied water conveying pipe 69 between the fifth liquefied water conveying pipe 69 and the cleaning tank 59 are respectively provided with a ninth regulating valve 70.

Further differing from example 1 in that the solid phase component in step S5 is discharged through the solid phase component outlet of the first centrifuge 9; the solid phase component consists mostly of organic acids in solid form, with small amounts of impurities carried thereon. Discharged from the solid phase component outlet of the first centrifuge 9, and then fed into the washing tank 59 for temporary storage.

Also, the difference from example 1 is that the steam generated during the second concentration reaction kettle 16 in step S8 is the steam which is not organic matter in the residual liquid after the electrolysis of the second concentration reaction kettle 16, and the steam generated during the second concentration process is substantially pure steam, and the steam generated during the second concentration process is liquefied by heat exchange through the heat source channel of the third heat exchanger 58 and the cold source continuously conveyed through the cold source channel of the third heat exchanger 58 to form liquefied water, and the formed liquefied water is conveyed to the sixth buffer tank 57 for temporary storage. The liquefied water temporarily stored in the sixth buffer tank 57 is fully mixed with the solid organic acid delivered to the cleaning tank 59 by delivering the liquefied water to the cleaning tank 59 under the driving of a stirring device arranged on the cleaning tank 59 to displace impurities carried on the surface of the solid organic acid, and then the suspension is delivered to the third centrifuge 60 for solid-liquid separation, and the liquid phase component is delivered to the seventh buffer tank 71; the solid phase component is re-delivered to the cleaning tank 59 through the second solid material delivering pipe 66, and is cleaned by the liquefied water temporarily stored in the sixth buffer tank 57, and the above process is repeated for a plurality of times until the value fed back by the second on-line densitometer 64 on the cleaning delivering pipe 61 reaches the preset range, and then is delivered to the third centrifuge 60 for final solid-liquid separation, the liquid phase is also delivered to the seventh buffer tank 71, and the cleaned solid phase component is discharged through the first solid material delivering pipe 65 for collection.

In comparison with example 1, in example 6, by providing the cleaning tank 59, the third centrifuge 60, the sixth buffer tank 57, the third liquefied water delivery pipe 56, the fourth liquefied water delivery pipe 68 and the fifth liquefied water delivery pipe 69, the separated solid organic acid is repeatedly cleaned by using relatively pure water vapor generated during the wastewater treatment process, and the liquid after the repeated cleaning contains part of the organic matters and is decomposed by the electrolytic tank 15, so that no additional wastewater requiring other systems to treat is generated during the cleaning process. When the sixth buffer tank 57 exceeds the warning water level, the liquid can be directly discharged outside through the fifth liquefied water supply pipe 69, and the discharge amount is controlled by a ninth regulator valve 70 attached to the fifth liquefied water supply pipe 69.

Example 7: as shown in fig. 1 and 2, the difference from embodiment 1 is that: in the embodiment, dioctyl phthalate waste water is taken as an example, and phthalic anhydride is taken as an example, and in the embodiment, the waste water is added into an acidification reaction kettle 8 to form phthalic acid; the amount of the acidic medium consisting of sulfuric acid and the acidic concentrate in the acidification tank 8 in the step S5 in the final operation stage is not as high as possible, but is preferably not as high as the phthalic acid solubility at 25 ℃. The relationship expressed in the following equation one should be satisfied:

Namely:

wherein A1 is a parameter fed back by an acidometer 24 arranged on the waste water acidification reaction kettle 8 containing the organic acid which is not acidified in the acidification reaction kettle 8; 10 ^-A2 The concentration of H+ when H+ in the concentrated sulfuric acid stored in the sulfuric acid storage tank 45 is completely hydrolyzed; 10 ^-A3 The concentration of H+ is the concentration of the acid liquor which is stored in the third buffer tank 14 and is concentrated by the first concentration reaction kettle 10 and is completely hydrolyzed; a4 is a parameter fed back by an acidimeter 24 arranged on the acidimeter 8 of the waste water acidizing reaction kettle 8 after acidizing in the acidizing reaction kettle 8;the concentration of phthalic anhydride in the waste water containing organic acid which is not acidified by the acidification reaction kettle 8; lambda is a coefficient; v1 is the volume of the organic acid-containing wastewater which is not acidified by the first buffer tank 7 and is fed to the acidification reactor 8; v2 is the volume of concentrated sulfuric acid delivered to the acidification reactor 8 through a sulfuric acid storage tank 45; v3 is the volume of the concentrated acid solution fed to the acidification reactor 8 via the third buffer tank 14.

And satisfies the relationship represented in the following formula two:

wherein,is the concentration of phthalic acid; k (K) _a1 A coefficient of primary ionization for phthalic acid; />Is the concentration of monohydrogen phthalate, C _H + is the hydrogen ion concentration.

Meanwhile, the phthalic acid also has secondary ionization, but the secondary ionization of the phthalic acid can be ignored due to the fact that the solution is an acid medium and the final solution is a strong acid medium. When phthalic anhydride forms phthalic acid and the degree of hydrolysis of the generated phthalic acid is suppressed in a strong acid medium, so that the solubility of phthalic acid in the strong acid medium is reduced, and more phthalic acid is obtained, however, the acid solution stored in the sulfuric acid storage tank 45 and the acid solution stored in the third buffer tank 14 and concentrated in the first concentration reaction kettle 10 are added to the acidification reaction kettle 8 together, and the acid solution should be controlled within a reasonable range, that is, the following relational expression is obtained by combining the first and second formulas:

Wherein: a1 is a parameter fed back by an acidometer 24 arranged on the waste water acidification reaction kettle 8 containing the organic acid which is not acidified in the acidification reaction kettle 8; 10 ^-A2 The concentration of H+ when H+ in the concentrated sulfuric acid stored in the sulfuric acid storage tank 45 is completely hydrolyzed; 10 ^-A3 The concentration of H+ is the concentration of the acid liquor which is stored in the third buffer tank 14 and is concentrated by the first concentration reaction kettle 10 and is completely hydrolyzed; v1 is the volume of the organic acid-containing wastewater which is not acidified by the first buffer tank 7 and is fed to the acidification reactor 8; v2 is the volume of concentrated sulfuric acid delivered to the acidification reactor 8 through a sulfuric acid storage tank 45; v3 is the volume of the concentrated acid liquor which is conveyed to the acidification reactor 8 through the third buffer tank 14;is the concentration of phthalic acid; k (K) _a1 A coefficient of primary ionization for phthalic acid; />Is the concentration of monohydrogen phthalate; />The concentration of phthalic anhydride in the waste water containing organic acid which is not acidified by the acidification reaction kettle 8; lambda is a coefficient.

And in this case, the total amount of the concentrated sulfuric acid stored in the sulfuric acid tank 45 and the acid solution concentrated in the first concentrating reaction tank 10 stored in the third buffer tank 14 is not as high as that of the acidification reaction tank 8, since a certain range is satisfied when The total volume of the solution is increased by continuously adding concentrated sulfuric acid and/or concentrated acid solution after the concentration is lower than the preset concentration, namely, the precipitated phthalic acid is redissolved due to the increase of the total volume of the solution.

The above-described embodiments are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention, so that all equivalent changes or modifications of the structure, characteristics and principles described in the claims should be included in the scope of the present invention.

Claims (8)

1. A plasticizer wastewater treatment device, which is characterized in that: the device comprises a wastewater conveying pipe (1), wherein a rectifying tower is communicated with the outlet end of the wastewater conveying pipe (1), a reboiling circulating pipe (2) is arranged on the rectifying tower, a first stop valve (3), a first booster pump (4), a reboiler (5) and a first online densimeter (6) are sequentially arranged along the direction from the inlet end of the reboiling circulating pipe (2) to the outlet end of the reboiling circulating pipe (2), the reboiling circulating pipe (2) between the first booster pump (4) and the reboiler (5) is communicated with the inlet end of a first buffer tank (7), the outlet end of the first buffer tank (7) is communicated with an acidification reaction kettle (8), the lower part of the acidification reaction kettle (8) is communicated with the inlet end of a first centrifugal machine (9), the liquid phase outlet end of the first centrifugal machine (9) is communicated with a first concentration reaction kettle (10), the outlet end of the first concentration reaction kettle (10) is communicated with a second buffer tank (11), the second buffer tank (11) is communicated with the first concentration reaction kettle (10) through a first concentrated solution conveying pipe (12), the second buffer tank (14) is communicated with the third concentrated solution conveying pipe (13), the upper concentrated solution (13) is communicated with the first buffer tank (13), the outlet end of the second buffer tank (11) is sequentially communicated with an electrolytic tank (15), a second concentration reaction kettle (16), a crystallization tank (17) and a second centrifuge (18).

2. The plasticizer wastewater treatment apparatus according to claim 1, wherein: the utility model provides a rectifying column on be provided with first liquefied water conveyer pipe (19), be provided with the heat source passageway of second heat exchanger (20) on first liquefied water conveyer pipe (19), be provided with alkali lye on the exit end of first liquefied water conveyer pipe (19) and prepare jar (21), alkali lye is prepared first liquefied water conveyer pipe (19) between jar (21) and second heat exchanger (20) and is provided with second liquefied water conveyer pipe (22), on first liquefied water conveyer pipe (19) and second liquefied water conveyer pipe (22) between jar (21) are prepared to second liquefied water, respectively be provided with first governing valve (23), alkali lye prepare jar (21) on be provided with agitating unit, alkali lye prepare jar (21), acidizing reation kettle (8), equally divide on first concentrated reation kettle (10) and be provided with acidimeter (24) correspondingly.

3. The plasticizer wastewater treatment apparatus according to claim 1, wherein: the rectifying column include tower body (25), from last first packing layer (26) and second packing layer (27) having set gradually down in tower body (25), tower body (25) and waste water conveyer pipe (1) between first packing layer (26) and second packing layer (27) are linked together, be provided with the cold source passageway of first heat exchanger (28) on waste water conveyer pipe (1), the entry end of first heat exchanger (28) heat source passageway is linked together with the top of tower body (25), the intercommunication has gas-liquid separation jar (29) on the exit end of first heat exchanger (28) heat source passageway, liquid phase exit end of gas-liquid separation jar (29) and tower body (25) above first packing layer (26) are linked together through crude alcohol back flow (30), be provided with second governing valve (31) on crude alcohol back flow (30), be provided with crude alcohol conveyer pipe (32) on crude alcohol back flow (30) between second governing valve (31) and gas-liquid separation jar (29), be provided with on crude alcohol conveyer pipe (32) third governing valve (33).

4. The plasticizer wastewater treatment apparatus according to claim 1, wherein: the first concentrated solution conveying pipe (12) is sequentially provided with a second booster pump (34), a fourth regulating valve (35) and a first one-way valve (36) along the direction from the first concentrated reaction kettle (10) to the second buffer tank (11), the electrolytic tank (15) and the second buffer tank (11) are communicated through a third concentrated solution conveying pipe (37), the third concentrated solution conveying pipe (37) is sequentially provided with a third booster pump (38) and a fifth regulating valve (39) along the direction from the second buffer tank (11) to the electrolytic tank (15), a third concentrated solution conveying pipe (37) between the third booster pump (38) and the fourth regulating valve (35) is communicated with the first concentrated solution conveying pipe (12) between the first one-way valve (36) and the second buffer tank (11) through a concentrated solution circulating pipe (40), the concentrated solution circulating pipe (40) is sequentially provided with a second stop valve (41) and a second concentrated solution circulating pipe (42) along the direction from the third concentrated solution conveying pipe (37) to the first concentrated solution conveying pipe (12), and a concentrated solution conveying pipe (13) between the third booster pump (38) and the second concentrated solution circulating pipe (35) is communicated with a concentrated solution conveying pipe (13) at the first concentrated solution conveying pipe (13).

5. The plasticizer wastewater treatment apparatus according to claim 1, wherein: the liquid phase outlet end of the second centrifugal machine (18) is communicated with a first centrifugal liquid conveying pipe (49), a fifth buffer tank (50) is arranged on the first centrifugal liquid conveying pipe (49), the fifth buffer tank (50) is communicated with the second concentration reaction kettle (16) through a second centrifugal liquid conveying pipe (51), a fifth booster pump (52) and a second liquid flow sensor (53) are sequentially arranged on the second centrifugal liquid conveying pipe (51) along the direction from the fifth buffer tank (50) to the second concentration reaction kettle (16), a third centrifugal liquid conveying pipe (54) is arranged on the second centrifugal liquid conveying pipe (51) between the fifth buffer tank (50) and the fifth booster pump (52), and an eighth regulating valve (55) is respectively arranged on the second centrifugal liquid conveying pipe (51) between the third centrifugal liquid conveying pipe (54) and the second liquid flow sensor (53).

6. The plasticizer wastewater treatment apparatus according to claim 1, wherein: the top that has washs jar (59) in first centrifuge (9) below intercommunication, washs jar (59) top and is provided with third centrifuge (60), the bottom of third centrifuge (60) entry end and washs jar (59) is linked together through wasing conveyer pipe (61), be provided with third stop valve (62) on wasing conveyer pipe (61), fourth booster pump (63) and second online densimeter (64), be provided with first solid material conveyer pipe (65) and second solid material conveyer pipe (66) on the solid phase exit end of third centrifuge (60), third centrifuge (60) are linked together through second solid material conveyer pipe (66), be provided with fourth stop valve (67) on first centrifuge (65) and the second solid material conveyer pipe (66), first centrifuge (9) and first concentrated reation kettle (10) are linked together through fourth centrifugal liquid conveyer pipe (79), be provided with seventh buffer tank (71) on fourth centrifugal liquid conveyer pipe (79), the liquid phase exit end of third centrifuge (60) is equally divided with seventh buffer tank (71).

7. The plasticizer wastewater treatment apparatus according to claim 6, wherein: the gas phase outlet end of the second concentration reaction kettle (16) is sequentially communicated with a third liquefied water conveying pipe (56) and a sixth buffer tank (57), a third heat exchanger (58) is arranged on the third liquefied water conveying pipe (56), the sixth buffer tank (57) is communicated with a cleaning tank (59) through a fourth liquefied water conveying pipe (68), a fifth liquefied water conveying pipe (69) is arranged on the fourth liquefied water conveying pipe (68), and a ninth regulating valve (70) is respectively arranged on the fourth liquefied water conveying pipe (68) between the fifth liquefied water conveying pipe (69) and the cleaning tank (59) and the fifth liquefied water conveying pipe (69).

8. The wastewater treatment method of the plasticizer wastewater treatment apparatus according to claim 1, comprising the steps of:

s5: the acidification reaction kettle (8) receives the wastewater conveyed by the first buffer tank (7) and reaches a preset liquid level, and then a preset amount of sulfuric acid is added into the acidification reaction kettle (8) to acidify the wastewater to form a strong acid environment; then continuously stirring, conveying to a first centrifugal machine (9) for solid-liquid separation after stirring for a preset time, conveying the liquid phase component to a first concentration reaction kettle (10) through a liquid phase component outlet of the first centrifugal machine (9), and discharging the solid phase component through a solid phase component outlet of the first centrifugal machine (9);

S6: the liquid entering the first concentration reaction kettle (10) can be started after reaching a preset liquid level, the liquid entering the first concentration reaction kettle (10) is concentrated for one time by the first concentration reaction kettle (10) to form an acidic concentrated solution, and the acidic concentrated solution is divided into two parts: part of the liquid is conveyed to a third buffer tank (14), and the rest of the liquid is conveyed to a second buffer tank (11) for temporary storage;

s7: adding sodium hydroxide alkali liquor into the second buffer tank (11) until the value fed back by an acidometer (24) on the second buffer tank (11) is neutral, so as to form neutral concentrated solution; delivering part of the neutral concentrated solution to an electrolytic tank (15) for carrying out electrolytic removal of residual organic matters contained in the period to form residual liquid after electrolysis;

s8: delivering the electrolyzed residual liquid to a second concentration reaction kettle (16) for secondary concentration to form secondary concentrated solution;

s9: and (3) conveying the secondary concentrated solution to one of crystallization tanks (17) to be connected with the secondary concentrated solution, adding seed crystals into the crystallization tank (17) to crystallize sodium sulfate after conveying, fully standing to complete the crystallization process, forming sodium sulfate crystals and residual liquid after crystallization, conveying the residual liquid into a second centrifuge (18) to perform solid-liquid separation, discharging the sodium sulfate crystals from a solid phase outlet of the second centrifuge (18), and discharging the residual liquid after crystallization from a liquid phase outlet of the second centrifuge (18).