CN115340238A - A method and system device for treating high-salt volatile organic wastewater - Google Patents

Abstract

The invention provides a method and a system device for treating high-salt volatile organic wastewater, which belong to the field of sewage treatment and comprise the following steps: pretreating high-salt volatile organic wastewater; pumping the pretreated wastewater, an acid regulator and an alkali regulator into a pipeline mixer, and controlling the hydrogen ion concentration of the wastewater; conveying the mixed liquid in the pipeline mixer to an evaporation reactor, and controlling the adding mode, the evaporation temperature and the evaporation time of persulfate; mixing the evaporated steam with ozone, passing through a condensing device, and then introducing into condensed water to secondarily degrade volatile organic compounds; the tail gas after reaction is purified and then is introduced into an evaporation reactor for recycling, and the distilled water after reaction can be used as condensed water or discharged. The invention realizes the gas-liquid two-phase synchronous oxidation of the high-salt volatile organic wastewater in the evaporation process, greatly shortens the treatment process flow, improves the utilization rate of resources, and ensures that the distilled water completely meets the recycling and emission standards.

Description

A method and system device for treating high-salt volatile organic wastewater

This application is submitted to the State Intellectual Property Office of China on July 26, 2019, the application number is 201910680992.X, and the title of the invention is "a method and system device for treating high-salt volatile organic wastewater". Divisional application.

technical field

The invention belongs to the technical field of sewage treatment, and in particular relates to a method and a system device for treating high-salt volatile organic wastewater.

Background technique

High-salt volatile organic wastewater refers to the total salt content greater than 1%, containing a large amount of K ⁺ , Na ⁺ , Ca ⁺ , SO ₄ ^2- , Cl ^- , CO ₃ ^2- and other free inorganic ions, as well as a large amount of organic compounds Such as phthalic acid, formaldehyde, medium and low-carbon alkanes, etc., which are characterized by complex components, toxicity, peculiar smell, large chroma, and poor biochemical properties. The main source of this type of wastewater is the high brine produced by petrochemical, coal chemical, pharmaceutical, printing and dyeing production processes and other wastewater treatment processes such as electrodialysis, nanofiltration membrane, reverse osmosis, etc., especially shale gas fracturing flowback fluid. If it is not disposed of properly, it will cause great pollution to the environment.

Evaporation technology has gradually attracted attention in the field of high-salt volatile organic wastewater treatment, and the high-salt volatile organic wastewater is directly evaporated and desalinated. However, evaporation technology cannot remove organic matter. Due to the increase in temperature and entrainment of mist, volatile organic matter in wastewater will condense into distilled water with water vapor, affecting the quality of distilled water and making it impossible to obtain pure distilled water. At the same time, organic matter may also increase in the evaporation reactor. Corrosion, fouling.

There is also an organic matter treatment device before evaporation, and then desalination treatment, that is, organic matter is degraded, and then deep desalination is carried out by thermal method. In this treatment method, the evaporation temperature is increased to obtain high-yield distilled water, but at the same time, the possibility of equipment fouling increases; and the pre-treatment requirements of various processes are different, and the series connection of multiple processes will make the process more lengthy and increase investment. Increased site requirements.

In addition, sulfur-containing gas field water is desulfurized by coagulation, organic matter is removed, ammonia nitrogen is degraded by oxidant, and desalination and advanced treatment are performed by evaporation. For example, the high-salt organic produced water treatment process of a natural gas field in central Sichuan, the treatment system includes chemical precipitation, stripping, coagulation sedimentation, and staged evaporation. High-salt organic shale gas produced water treatment process in the Wattenberg Oilfield in northeast Colorado. The system includes three-phase separation, precipitation softening, walnut shell filtration, and membrane distillation. All of the above processes separate organic matter and desalination, and all of them have the technical problem of long process flow.

Advanced oxidation technology, also known as deep oxidation technology, is characterized by the generation of free radicals (hydroxyl free radicals, sulfuric acid free radicals, etc.) It can completely mineralize or decompose most organic matter, and has a good application prospect. However, in the presence of inorganic salts, free radicals and Cl-, CO ₃ ^2- , HCO ₃ ^- , etc. may be quenched, affecting the degradation of organic matter, and there are many organic matter residues.

With the introduction of the concept of "zero discharge", the standard of sewage treatment has been further improved. How to deal with high-salt volatile organic wastewater to meet the discharge requirements is currently required.

Contents of the invention

The purpose of the present invention is to provide a method and system device for treating high-salt volatile organic wastewater. The method for treating high-salt volatile organic wastewater provided by the present invention adopts gas-liquid two-phase synchronous oxidation, and distilled water meets reuse and discharge standards , and at the same time reduce the energy consumption of free radical activation, improve the utilization rate of resources, and greatly shorten the process flow.

In order to achieve the above object, the present invention provides the following technical solutions:

The invention provides a method for treating high-salt volatile organic wastewater, comprising the following steps:

(1) Prepare organic wastewater and raw materials, SS in organic wastewater≤10mg/L;

(2) adding the acid regulator and the alkali regulator to the organic wastewater to form a mixed solution, the pH value is 4 to 5;

(3) Add persulfate and evaporate, the evaporation temperature is 60-70°C, the hydraulic retention time is 1.5-2.5h; the mass concentration ratio of COD _Cr to S ₂ O ₈ ^2- in the solution is 4-5, the mass of persulfate The concentration is 5%;

(4) Pass into ozone, enter the condensation treatment step after the mixed reaction of steam and ozone in the solution; Described ozone mass concentration is 20～40mg/L;

(5) Carry out crystallization treatment to the concentrated water.

Preferably, the acid regulator is HCl or sulfuric acid.

Preferably, the persulfate is one or more of sodium persulfate, potassium persulfate and ammonium persulfate.

Preferably, the persulfate is sodium persulfate.

Preferably, the pH in the step (2) is 5.

Preferably, the evaporation temperature is 60°C; the hydraulic retention time is 2 hours.

Preferably, the step (4) also includes a tail gas recycling step, the tail gas recycling step is: returning the reacted part of the tail gas into the step (3) for reuse, and discharging the tail gas that meets the discharge conditions; The tail gas is the steam part that cannot be condensed; about 30% of the tail gas is refluxed.

The invention provides a system device for treating high-salt volatile organic wastewater, which includes a waste water tank 1, a waste water pump 2, an acid solution tank, an alkali solution tank, an acid solution pump, an alkali solution pump, a pipeline mixer 5, a Sulphate solution tank 6, metering pump 7, ozone generator 8, blower 9, evaporation reactor 10, crystallization device 11, condensation device 13 and distilled water storage tank 14; waste water tank 1 is connected with waste water pump 2, waste water pump 2 is connected with pipeline The mixer 5 is connected, the acid solution tank is connected with the acid solution pump, the lye solution tank is connected with the lye solution pump, the acid solution pump and the lye solution pump are respectively connected with the pipeline mixer 5, and the pipeline mixer 5 is connected with the evaporation reactor 10; Sulphate solution tank 6 is connected with metering pump 7, and metering pump 7 is connected with evaporation reactor 10; The condensing device 13 is connected, and the condensing device 13 is connected with the evaporation reactor 10 .

Preferably, the system device is also provided with a waste water pretreatment device 19 , and the pretreatment device 19 is connected to the waste water tank 1 .

Preferably, a tail gas pipe 16 is also provided, one end of the tail gas pipe 16 is connected to the distilled water storage tank 14 , and the connection point of the other end is set between the blower 9 and the evaporation reactor 10 .

The invention provides a method for treating high-salt volatile organic wastewater, comprising the following steps: (1) preparing organic wastewater and raw materials, SS≤10mg/L in organic wastewater; (2) adding acid regulator and alkali regulator A mixed solution is formed in organic wastewater, with a pH value of 4-5; (3) add persulfate, evaporate, the evaporation temperature is 60°C, and the hydraulic retention time is 1.5-2.5h; COD _Cr and S ₂ O ₈ ^2- mass in the solution Concentration ratio is 4～5, and the mass concentration of persulfate radical is 5%; (4) feeds ozone, enters condensation treatment step after the mixed reaction of steam and ozone in the solution; Described ozone mass concentration is 20～40mg/L; ( 5) Carry out crystallization treatment to concentrated water.

In the present invention, the step (1) can greatly reduce the fouling possibility of the evaporation equipment and ensure the stable operation of the equipment.

Step (2) mainly controls the amount and type of free radicals generated, while reducing the formation of carbonate scaling. When pH value is 4～5 in step (2), adding persulfate in step (3) can activate and produce a large amount of highly oxidizing sulfuric acid free radicals, and equipment requirement is not high; When pH value is greater than 5, The production of sulfuric acid free radicals gradually decreases, and the production of hydroxyl free radicals with relatively low oxidation ability gradually increases, and the hydrolysis of sulfuric acid free radicals will be accelerated under alkaline conditions, thereby generating more hydroxyl free radicals; when the pH value is less than 4 , higher corrosion resistance requirements for equipment, and a large amount of acid conditioner needs to be added, which will increase operating costs.

Step (3) mainly controls the generation rate of sulfuric acid free radicals, and reduces the overflow of volatile organic compounds. When the temperature is 60°C-70°C, the generation rate of sulfuric acid free radicals is accelerated, the content of volatile organic compounds in the gas is low, and the stable operation of the equipment is not suitable for scaling. When the temperature is higher than 70°C, a large amount of volatile organic compounds in the gas will overflow, the concentration of organic compounds in the liquid phase will decrease, the concentration of oxidants relative to organic compounds will increase, and the oxidation efficiency will decrease, and the concentration of organic compounds in distilled water will increase, which cannot meet the emission requirements and cause scaling of equipment. Possibilities increase. When the temperature is lower than 60°C, the generation efficiency of sulfuric acid radicals is low, which is not enough to oxidize organic matter in the liquid phase, and the yield of distilled water is low, so the desalination effect cannot be achieved.

Step (3) mainly controls the concentration ratio of organic matter and persulfate to improve the oxidation efficiency of organic matter. When the mass concentration ratio of COD _Cr to S ₂ O ₈ ^2- is 4-5 and the mass fraction of persulfate is 5%, the removal rate of organic matter is the highest. Persulfate is the source of sulfuric acid free radicals. When the concentration ratio of organic matter to persulfate is high, the concentration of persulfate is too low, and the generation efficiency of sulfuric acid free radicals is low, which is not enough to oxidize organic matter in the liquid phase. When the concentration ratio of organic matter to persulfate is low, the concentration of persulfate is too high, the sulfate radical will react with persulfate, and the sulfate radical will self-quench, resulting in a decrease in the concentration of sulfate radical, which is not enough to oxidize the liquid phase Medium organic matter.

Step (4) mainly controls the volatile organic compounds in the gas to ensure the stable quality of the distilled water. When the ozone concentration is 20-40mg/L, use steam to catalyze ozone to oxidize gaseous small molecule organic matter. The ozone tangentially enters the evaporation reactor to increase the time of ozone oxidation. After the mixed gas passes through the condensing device, it is connected to the condensed water. Heterogeneous deep oxidation of organics in condensed water. When the ozone concentration is less than 20mg/L, it is not enough to oxidize the volatile organic compounds in the gas, and the condensed water cannot meet the emission requirements. When the ozone concentration is greater than 40mg/L, the ozone concentration in the tail gas is too high, resulting in waste of resources and air pollution.

Step (5) mainly obtains pure salt. The organic matter in the brine will affect the quality of the salt. The organic matter in the high-salt organic wastewater is degraded and concentrated through the evaporation reactor to obtain pure concentrated brine, and then crystallized to obtain pure and high-quality salt.

Further, in the present invention, there is also a tail gas recovery and utilization step in the step (4), the tail gas recovery and utilization step is: returning part of the tail gas after the reaction into the step (3) for reuse, and the tail gas that meets the discharge conditions Carry out discharge treatment; the tail gas is the steam part that cannot be condensed; about 30% of the tail gas is refluxed. The tail gas recovery and utilization step mainly controls the recovery and utilization of tail gas. When about 30% of the tail gas is recirculated, the ozone can be fully utilized to enhance the oxidation of organic matter in the gas phase. When the backflow of the tail gas is less than 30%, the concentration of ozone in the tail gas is too high, resulting in waste of resources and pollution of the atmosphere. When the tail gas reflux is greater than 30%, the amount of air entering the reactor is too much, which reduces the ozone concentration in the gas phase of the reactor, which is not enough to oxidize the volatile organic compounds in the gas, and the condensed water cannot meet the discharge requirements.

Further, in the present invention, the persulfate is sodium persulfate. When the dosage needs to be large, potassium persulfate cannot be completely dissolved, ammonium persulfate may cause the problem of ammonia nitrogen rise in distilled water, and sodium persulfate is the most suitable persulfate.

The invention provides a system device for treating high-salt volatile organic wastewater, which includes a waste water tank 1, a waste water pump 2, an acid solution tank, an lye solution tank, an acid solution pump, an lye solution pump, a pipeline mixer 5, persulfuric acid Salt solution tank 6, metering pump 7, ozone generator 8, blower 9, evaporation reactor 10, crystallization device 11, condensation device 13 and distilled water storage tank 14; waste water tank 1 is connected with waste water pump 2, and waste water pump 2 is mixed with pipeline The device 5 is connected, the acid solution tank is connected with the acid solution pump, the lye solution tank is connected with the lye solution pump, the acid solution pump and the lye solution pump are respectively connected with the pipeline mixer 5, and the pipeline mixer 5 is connected with the evaporation reactor 10; persulfuric acid Salt solution tank 6 is connected with metering pump 7, metering pump 7 is connected with evaporation reactor 10; The device 13 is connected, and the condensing device 13 is connected with the evaporation reactor 10 . In the present invention, distilled water is recovered from the distilled water storage tank 14, tail gas is also discharged from the distilled water storage tank 14, and pure salt is obtained from the crystallization device 11.

In the present invention, the gas-liquid two-phase synchronous oxidation technology is adopted to continuously oxidize volatile organic compounds in different phases of the same evaporation reactor, to remove organic compounds synchronously during the evaporation desalination process, to control the volatile organic compounds during the evaporation process by gas-phase oxidation, and to reduce the tail gas part The reflux makes full use of the ozone, part of the distilled water is condensed and reused, and the rest can be directly discharged.

In the present invention, by adding persulfate into the evaporation reactor, the oxidant is activated by evaporation heat to generate free radicals, thereby oxidizing volatile organic compounds. In order to ensure the water quality of distilled water, ozone is added to the steam to oxidize the volatile organic matter entrained by the mist. Organic matter, realize desalination and remove organic matter at the same time, greatly shorten the process flow.

The present invention uses persulfate and ozone as oxidants to effectively remove gas-liquid two-phase organic matter in the evaporation process of high-salt volatile organic wastewater, and uses the heat in the evaporation process for the generation of free radicals, thereby decomposing organic matter in the evaporation process , to ensure the quality of distilled water, while reducing the energy consumption of free radical activation, adding ozone in the gas phase to control the entry of volatile organic compounds into distilled water, and deep oxidation in distilled water, which greatly shortens the treatment process and saves costs. According to the application and emission standards, the concentration of volatile organic compounds in the gas is less than the detection limit.

Description of drawings

Fig. 1 is a schematic diagram of device structure in the present invention;

Fig. 2 is a schematic diagram of device structure optimized in the present invention;

1. Waste water tank, 2. Waste water pump, 3. Acid and lye tank, 4. Acid and lye pump, 5. Pipeline mixer, 6. Persulfate solution tank, 7. Metering pump, 8 .Ozone generator, 9. Blower, 10. Evaporation reactor, 11. Crystallization device, 12. Concentrated brine, 13. Condenser, 14. Distilled water storage tank, 15. Condensation reuse, 16. Exhaust pipe, 17. Ozone Reuse, 18. water outlet, 19. pretreatment device.

Detailed ways

The invention provides a method for treating high-salt volatile organic wastewater, comprising the following steps:

(1) Prepare organic wastewater and raw materials, SS in organic wastewater≤10mg/L;

(2) adding the acid regulator and the alkali regulator into the organic wastewater to form a mixed solution with a pH of 4 to 5;

(3) Add persulfate and evaporate, the evaporation temperature is 60-70°C, the hydraulic retention time is 1.5-2.5h; the mass concentration ratio of COD _Cr to S ₂ O ₈ ^2- in the solution is 4-5, the mass of persulfate The concentration is 5%;

(4) Pass into ozone, enter the condensation treatment step after the mixed reaction of steam and ozone in the solution; Described ozone mass concentration is 20～40mg/L;

(5) Carry out crystallization treatment to the concentrated water.

In the present invention, in step (1), the high-salt volatile organic wastewater is preferably shale gas fracturing flowback fluid.

In the present invention, in step (3), the dosing method is preferably once every 60 minutes.

In the present invention, in step (3), adding persulfate and evaporation can be added simultaneously, or can be added before or after evaporation.

In the present invention, in step (5), concentrated water is concentrated water obtained after evaporation.

In the present invention, the tail gas recirculation is to increase the utilization rate of ozone, and perform secondary oxidation to ensure that the exhaust gas is discharged up to the standard.

The invention provides a system device for treating high-salt volatile organic wastewater. In the present invention, the above-mentioned devices are connected by pipelines. The various tanks, instruments and devices used, as well as the reactor, are conventional equipment and structures.

In order to further illustrate the present invention, the technical solutions provided by the present invention will be described in detail below in conjunction with the accompanying drawings and examples, but they should not be construed as limiting the protection scope of the present invention.

Example 1

A gas-liquid two-phase synchronous oxidation method for treating high-salt volatile organic wastewater, the steps are as follows:

(1) Pretreatment of high-salt volatile organic wastewater, so that the SS (suspended solids) in the wastewater is lower than 10mg/L; the pretreatment method can be treated by membrane, coagulation, or filtration . Membrane treatment, coagulation or filtration methods are conventional wastewater pretreatment methods.

(2) pump organic waste water, acid conditioner and alkali conditioner into pipeline mixer, and control the initial pH of waste water to be 4.5;

(3) According to the ratio of COD _Cr and S ₂ O ₈ ^2- mass concentration ratio of 4.5, pump into the evaporation reactor a persulfate with a persulfate mass fraction of 5%;

(4) Transport the mixed liquid in the pipeline mixer to the evaporation reactor, and control the evaporation temperature to be 65°C;

(5) Mix and react the evaporating steam with ozone with a concentration of 30mg/L, and use steam to catalyze the ozone to oxidize gaseous small molecule organic matter. ;Ozone is passed into the liquid surface of the evaporation reactor along the tangential direction of the evaporation reactor through the blower, so that the evaporation steam and the gas are mixed and reacted, and the mixed gas is connected to the condensed water after passing through the condensation device, and the volatile organic compounds are degraded for the second time;

(6) Return 30% of the tail gas after the reaction into the evaporation reactor for reuse. The distilled water after the reaction can be reused or discharged as condensation. The COD (chemical oxygen demand) value of the wastewater is less than 60mg/L, and the volatile organic compounds in the gas The concentration is less than the detection limit.

Example 2

A gas-liquid two-phase synchronous oxidation system device for treating high-salt volatile organic wastewater, which is equipped with a wastewater tank 1, a wastewater pump 2, an acid solution tank, an lye solution tank, an acid solution pump, an lye solution pump, and a pipeline mixer 5, Persulfate solution tank 6, metering pump 7, ozone generator 8, blower 9, evaporation reactor 10, crystallization device 11, condensation device 13 and distilled water storage tank 14; waste water tank 1 is connected with waste water pump 2, and waste water pump 2 is connected with The pipeline mixer 5 is connected, the acid-base solution tank is connected with the acid-base solution pump, the acid solution pump and the lye pump are connected with the pipeline mixer 5, and the pipeline mixer 5 is connected with the evaporation reactor 10; the persulfate solution tank 6 and the metering The pump 7 is connected, the metering pump 7 is connected with the evaporation reactor 10; the crystallization device 11 is connected with the evaporation reactor 10, the ozone generator 8 is connected with the evaporation reactor 10 through the blower 9, the distilled water storage tank 14 is connected with the condensation device 13, and the condensation device 13 is connected with evaporation reactor 10.

The distilled water is recovered from the distilled water storage tank 14, the tail gas is also discharged from the distilled water storage tank 14, and the pure salt is obtained from the crystallization device 11.

Example 3

A gas-liquid two-phase synchronous oxidation system device for treating high-salt volatile organic wastewater, which is equipped with a wastewater pretreatment device 19, a wastewater tank 1, a wastewater pump 2, an acid solution tank, an lye solution tank, an acid solution pump, and an lye solution pump , pipeline mixer 5, persulfate solution tank 6, metering pump 7, ozone generator 8, blower 9, evaporation reactor 10, crystallization device 11, condensation device 13, distilled water storage tank 14 and tail gas pipe 16, waste water pretreatment The device 19 is connected with the waste water tank 1, the waste water tank 1 is connected with the waste water pump 2, the waste water pump 2 is connected with the pipeline mixer 5, the acid-base liquid tank is connected with the acid-base liquid pump, and the acid liquid pump and the lye pump are connected with the pipeline mixer 5 Connected, the pipeline mixer 5 is connected with the evaporation reactor 10; the persulfate solution tank 6 is connected with the metering pump 7, and the metering pump 7 is connected with the evaporation reactor 10; the crystallization device 11 is connected with the evaporation reactor 10, and the ozone generator 8 passes through The blower 9 is connected to the evaporation reactor 10, the distilled water storage tank 14 is connected to the condensing device 13, and the condensing device 13 is connected to the evaporation reactor 10; one end of the tail gas pipe 16 is connected to the distilled water storage tank 14, and the other end is connected to the blower 9 and the evaporator. Between the reactors 10. The equipment is connected by pipes.

The distilled water is recovered from the distilled water storage tank 14, the tail gas is discharged from the tail gas pipe 16, and the pure salt is obtained from the crystallization device 11.

The operating steps of the system device are as described in Example 1. The system can adopt the continuous evaporation method, that is, crystallize while evaporating, and there is always concentrated water leading to the crystallization device. Continuous evaporation means that waste water is always fed into the evaporation reactor, concentrated water and fresh water are always produced, crystallization is always carried out, and gas recovery is always carried out. Continuous evaporation is adding while evaporating.

It is also possible to adopt intermittent evaporation instead of continuous evaporation. During the evaporation process, the gas is always fed and recovered. After the evaporation is completed, the concentrated water is fed into the crystallization device for crystallization. Dosing of chemicals is added before evaporation, and the dosage is added in the same proportion as continuous evaporation.

Used tank, instrument and device, and reactor are all conventional equipment and structures, such as condensing device 13 is a LJEP-NFDK type condensed water recovery device, evaporation reactor 10 is a HC-DX evaporator reactor; crystallization device 11 is a DBT Type crystallizer, ozone generator 8 is CF-G-2 ozone generator. The following are the same.

Example 4

After pretreatment 19, the SS in the wastewater was reduced from 74mg/L to 7mg/L, and then passed into the waste water tank, the COD _Cr concentration in the sewage pump 2 was 546mg/L, the Cl ^- content was 21860mg/L, and the pH= The high-salt organic wastewater of 7.5 is pumped into the pipeline mixer 5, and at the same time, the 1:1 HCl in the acid solution tank and the alkali solution tank 3 is pumped into the pipeline mixer to fully mix, and the pH of the wastewater is adjusted to 5. The evaporation temperature of the evaporation reactor is controlled to be 60° C., and the hydraulic retention time is 2 hours. Add 109.2 mg/L of persulfate with a mass fraction of 5% in the persulfate solution tank to the evaporation reactor 10 according to the ratio of COD _Cr to S ₂ O ₈ ^2- mass concentration ratio of 5. At the same time, the concentration of 20 mg/L ozone produced by the ozone generator 8 is added to the steam in the evaporation reactor 10 to continue to oxidize the small molecule organic matter in the steam. After passing the steam through the condensing device 13, distilled water is obtained and enters the distilled water storage tank 14, which can be reused 15 in the condensing device or directly discharged 18, and the ozone in the tail gas is passed through the tail gas pipe 16 and then passed into the steam in the evaporation reactor for reuse. The COD in the brine entering the crystallization device 11 is 87 mg/L, the Cl content is 47642 mg/L, ^and the COD in the distilled water 14 is 41 mg/L.

Example 5

After pretreatment 19, the SS in the wastewater is reduced from 84mg/L to 6mg/L, and then passed into the waste water tank, the COD _Cr concentration in the sewage pump 2 is 233mg/L, the Cl ^- content is 24220mg/L, and the pH= 7.5 high-salt organic wastewater is pumped into pipeline mixer 5, and at the same time, 1:1 HCl in acid solution tank and alkali solution tank 3 is pumped into pipeline mixer to fully mix, and the pH of wastewater is adjusted to 4. The evaporation temperature of the evaporation reactor is controlled to be 60° C., and the hydraulic retention time is 2 hours. Add 109.2 mg/L of persulfate with a mass fraction of 5% in the persulfate solution tank to the evaporation reactor 10 according to the ratio of COD _Cr to S ₂ O ₈ ^2- mass concentration ratio of 5. At the same time, the concentration of 20 mg/L ozone produced by the ozone generator 8 is added to the steam in the evaporation reactor 10 to continue to oxidize the small molecule organic matter in the steam. After passing the steam through the condensing device 13, the obtained distilled water 14 can be reused 15 in the condensing device or directly discharged 18, and the ozone in the tail gas is passed into the steam in the evaporation reactor through the tail gas pipe 16 for reuse. The COD in the brine entering the crystallization device 11 is 71 mg/L, the Cl content is 50920 mg/L, ^and the COD in the distilled water 14 is 38 mg/L.

Example 6

After pretreatment 19, the SS in the wastewater is reduced from 166mg/L to 8mg/L, and then passed into the waste water tank, the COD _Cr concentration in the sewage pump 2 is 1428mg/L, the Cl ^- content is 18220mg/L, and the pH= The high-salt organic wastewater of 6.5 is pumped into the pipeline mixer 5, and at the same time, the 1:1 HCl in the acid solution tank and the alkali solution tank 3 is pumped into the pipeline mixer to fully mix, and the pH of the wastewater is adjusted to 4. The evaporation temperature of the evaporation reactor is controlled to be 70° C., and the hydraulic retention time is 2 hours. Add 357 mg/L of persulfate with a mass fraction of 5% in the persulfate solution tank to the evaporation reactor 10 according to the ratio of COD _Cr to S ₂ O ₈ ^2- mass concentration ratio of 5. At the same time, the concentration of 20 mg/L ozone produced by the ozone generator 8 is added to the steam in the evaporation reactor 10 to continue to oxidize the small molecule organic matter in the steam. After passing the steam through the condensing device 13, the obtained distilled water 14 can be reused 15 in the condensing device or directly discharged 18, and the ozone in the tail gas is passed through the tail gas pipe 16 and then passed into the steam in the evaporation reactor for reuse for ozone reuse 17. The COD in the brine entering the crystallization device 11 is 45 mg/L, the Cl content is 52648 mg/L, ^and the COD in the distilled water 14 is 57 mg/L.

Example 7

After pretreatment 19, the SS in the wastewater is reduced from 182mg/L to 8mg/L, and then passed into the wastewater tank, the COD _Cr concentration in the sewage pump 2 is 899mg/L, the Cl ^- content is 20618mg/L, and the pH= The high-salt organic wastewater of 7 is pumped into the pipeline mixer 5, and at the same time, the 1:1 HCl in the acid solution tank and the alkali solution tank 3 is pumped into the pipeline mixer to fully mix, and the pH of the wastewater is adjusted to 4. The evaporation temperature of the evaporation reactor is controlled to be 70° C., and the hydraulic retention time is 2 hours. Add 224.8 mg/L of persulfate with a mass fraction of 5% in the persulfate solution tank to the evaporation reactor 10 according to the ratio of COD _Cr to S ₂ O ₈ ^2- mass concentration ratio of 4. At the same time, the concentration of 20 mg/L ozone produced by the ozone generator 8 is added to the steam in the evaporation reactor 10 to continue to oxidize the small molecule organic matter in the steam. After passing the steam through the condensing device 13, the obtained distilled water 14 can be reused 15 in the condensing device or directly discharged 18, and the ozone in the tail gas is passed into the steam in the evaporation reactor through the tail gas pipe 16 for reuse. The COD in the brine entering the crystallization device 11 is 27 mg/L, the Cl content is 59208 mg/L, ^and the COD in the distilled water 14 is 46 mg/L.

Example 8

After pretreatment 19, the SS in the waste water was reduced from 109 mg/L to 7 mg/L, and then passed into the waste water tank, the COD _Cr concentration in the sewage pump 2 was 1104 mg/L, the Cl ^- content was 23323 mg/L, and the pH= The high-salt organic wastewater of 7 is pumped into the pipeline mixer 5, and at the same time, the 1:1 HCl in the acid solution tank and the alkali solution tank 3 is pumped into the pipeline mixer to fully mix, and the pH of the wastewater is adjusted to 4. The evaporation temperature of the evaporation reactor is controlled to be 70° C., and the hydraulic retention time is 2 hours. Add 276 mg/L of persulfate with a mass fraction of 5% in the persulfate solution tank to the evaporation reactor 10 according to the ratio of COD _Cr to S ₂ O ₈ ^2- mass concentration ratio of 4. At the same time, add ozone with a concentration of 40 mg/L generated by the ozone generator 8 into the steam in the evaporation reactor 10 to continue to oxidize the small molecule organic matter in the steam. After passing the steam through the condensing device 13, the obtained distilled water 14 can be reused 15 in the condensing device or directly discharged 17, and the ozone in the tail gas is passed into the steam in the evaporation reactor through the tail gas pipe 16 for reuse. The COD in the brine entering the crystallization device 11 is 31 mg/L, the Cl content is 65614 mg/L, ^and the COD in the distilled water 14 is 25 mg/L.

Example 9

After pretreatment 19, the SS in the wastewater was reduced from 74mg/L to 7mg/L, and then passed into the waste water tank, the COD _Cr concentration in the sewage pump 2 was 546mg/L, the Cl ^- content was 21860mg/L, and the pH= The high-salt organic waste water of 7.5 is pumped in the pipeline mixer 5. The evaporation temperature of the evaporation reactor is controlled to be 60° C., and the hydraulic retention time is 2 hours. Add 109.2 mg/L of persulfate with a mass fraction of 5% in the persulfate solution tank to the evaporation reactor 10 according to the ratio of COD _Cr to S ₂ O ₈ ^2- mass concentration ratio of 5. At the same time, the concentration of 20 mg/L ozone produced by the ozone generator 8 is added to the steam in the evaporation reactor 10 to continue to oxidize the small molecule organic matter in the steam. After passing the steam through the condensing device 13, the obtained distilled water 14 can be reused 15 in the condensing device or directly discharged 18, and the ozone in the tail gas is passed into the steam in the evaporation reactor through the tail gas pipe 16 for reuse. The COD in the brine entering the crystallization device 11 is 94 mg/L, the Cl content is 47642 mg/L, ^and the COD in the distilled water 14 is 83 mg/L.

Example 10

After pretreatment 19, the SS in the wastewater is reduced from 84mg/L to 6mg/L, and then passed into the waste water tank, the COD _Cr concentration in the sewage pump 2 is 233mg/L, the Cl ^- content is 24220mg/L, and the pH= The high-salt organic waste water of 7.5 is pumped in the pipeline mixer 5. Control the evaporation temperature of the evaporation reactor to 50°C, and the hydraulic retention time to 2 hours. Add 109.2 mg/L of persulfate with a mass fraction of 5% in the persulfate solution tank to the evaporation reactor 10 according to the ratio of COD _Cr to S ₂ O ₈ ^2- mass concentration ratio of 5. At the same time, the concentration of 20 mg/L ozone produced by the ozone generator 8 is added to the steam in the evaporation reactor 10 to continue to oxidize the small molecule organic matter in the steam. After passing the steam through the condensing device 13, the obtained distilled water 14 can be reused 15 in the condensing device or directly discharged 18, and the ozone in the tail gas is passed into the steam in the evaporation reactor through the tail gas pipe 16 for reuse. The COD in the brine entering the crystallization device 11 is 85 mg/L, the Cl content is 36840 mg/L, ^and the COD in the distilled water 14 is 69 mg/L.

Comparative example 1

After pretreatment 19, the SS in the wastewater is reduced from 182mg/L to 8mg/L, and then passed into the wastewater tank, the COD _Cr concentration in the sewage pump 2 is 899mg/L, the Cl ^- content is 20618mg/L, and the pH= The high-salt organic wastewater of 7 is pumped into the pipeline mixer 5, and at the same time, the 1:1 HCl in the acid solution tank and the alkali solution tank 3 is pumped into the pipeline mixer to fully mix, and the pH of the wastewater is adjusted to 4. Control the evaporation temperature of the evaporation reactor to 50°C, and the hydraulic retention time to 2 hours. Add 168.6 mg/L of persulfate with a mass fraction of 5% in the persulfate solution tank to the evaporation reactor 10 according to the ratio of COD _Cr to S ₂ O ₈ ^2- mass concentration ratio of 3. At the same time, the concentration of 20 mg/L ozone produced by the ozone generator 8 is added to the steam in the evaporation reactor 10 to continue to oxidize the small molecule organic matter in the steam. After passing the steam through the condensing device 13, the obtained distilled water 14 can be reused 15 in the condensing device or directly discharged 18, and the ozone in the tail gas is passed into the steam in the evaporation reactor through the tail gas pipe 16 for reuse. The COD in the brine entering the crystallization device 11 is 124 mg/L, the Cl content is 31208 mg/L, ^and the COD in the distilled water 14 is 106 mg/L.

Comparative example 2

After pretreatment 19, the SS in the wastewater is reduced from 182mg/L to 8mg/L, and then passed into the wastewater tank, the COD _Cr concentration in the sewage pump 2 is 899mg/L, the Cl- content is 20618mg/L, and the pH= The high-salt organic wastewater of 7 is pumped into the pipeline mixer 5, and at the same time, the 1:1 HCl in the acid solution tank and the alkali solution tank 3 is pumped into the pipeline mixer to fully mix, and the pH of the wastewater is adjusted to 5. The evaporation temperature of the evaporation reactor is controlled to be 70° C., and the hydraulic retention time is 2 hours. Add 168.6 mg/L of persulfate with a mass fraction of 5% in the persulfate solution tank to the evaporation reactor 10 according to the ratio of COD _Cr to S ₂ O ₈ ^2- mass concentration ratio of 3. At the same time, the concentration of 15mg/L ozone produced by the ozone generator 8 is added to the steam in the evaporation reactor 10 to continue to oxidize the small molecule organic matter in the steam. After passing the steam through the condensing device 13, the obtained distilled water 14 can be reused 15 in the condensing device or directly discharged 18, and the ozone in the tail gas is passed into the steam in the evaporation reactor through the tail gas pipe 16 for reuse. The COD in the brine entering the crystallization device 11 is 118 mg/L, the Cl- content is 59208 mg/L, and the COD in the distilled water 14 is 146 mg/L.

Comparative example 3

After pretreatment 19, the SS in the wastewater is reduced from 182mg/L to 8mg/L, and then passed into the wastewater tank, the COD _Cr concentration in the sewage pump 2 is 899mg/L, the Cl- content is 20618mg/L, and the pH= The high-salt organic wastewater of 7 is pumped into the pipeline mixer 5, and at the same time, the 1:1 HCl in the acid solution tank and the alkali solution tank 3 is pumped into the pipeline mixer to fully mix, and the pH of the wastewater is adjusted to 4. Control the evaporation temperature of the evaporation reactor at 50°C and the hydraulic retention time at 1 hour. Add 168.6 mg/L of persulfate with a mass fraction of 5% in the persulfate solution tank to the evaporation reactor 10 according to the ratio of COD _Cr to S ₂ O ₈ ^2- mass concentration ratio of 3. At the same time, the concentration of 20 mg/L ozone produced by the ozone generator 8 is added to the steam in the evaporation reactor 10 to continue to oxidize the small molecule organic matter in the steam. After passing the steam through the condensing device 13, the obtained distilled water 14 can be reused 15 in the condensing device or directly discharged 18, and the ozone in the tail gas is passed into the steam in the evaporation reactor through the tail gas pipe 16 for reuse. The COD in the brine entering the crystallization device 11 is 267 mg/L, the Cl- content is 28830 mg/L, and the COD in the distilled water 14 is 116 mg/L.

Comparative example 4

After pretreatment 19, the SS in the wastewater is reduced from 109mg/L to 7mg/L, and then passed into the wastewater tank, the COD _Cr concentration in the sewage pump 2 is 1104mg/L, the Cl- content is 23323mg/L, and the pH= The high-salt organic waste water of 7 is pumped into the pipeline mixer 5, and at the same time, the 1:1 NaOH in the acid solution tank and the alkali solution tank 3 is pumped into the pipeline mixer to fully mix, and the pH of the wastewater is adjusted to 9. Control the evaporation temperature of the evaporation reactor to 50°C, and the hydraulic retention time to 2 hours. Add 207 mg/L of persulfate with a mass fraction of 5% in the persulfate solution tank to the evaporation reactor 10 according to the ratio of COD _Cr to S ₂ O ₈ ^2- mass concentration ratio of 3. At the same time, the concentration of 15mg/L ozone produced by the ozone generator 8 is added to the steam in the evaporation reactor 10 to continue to oxidize the small molecule organic matter in the steam. After passing the steam through the condensing device 13, the obtained distilled water 14 can be reused 15 in the condensing device or directly discharged 18, and the ozone in the tail gas is passed into the steam in the evaporation reactor through the tail gas pipe 16 for reuse. The COD in the brine entering the crystallization device 11 is 384 mg/L, the Cl content is 29140 mg/L, ^and the COD in the distilled water 14 is 182 mg/L.

Comparative example 5

The COD _Cr concentration is 898mg/L, the Cl ^- content is 27410mg/L, and the high-salt organic wastewater with pH=9.14 is treated by chemical precipitation, steam stripping, coagulation sedimentation, and segmental evaporation, and the COD in the first stage of distilled water is 1883mg/L. After the removal, the distilled water can be reduced to 44mg/L after the second stage, and the COD in the concentrated water is still 460mg/L. The process does not realize the complete removal of pollutants. The present invention completely removes organic matter and does not require subsequent treatment. In addition, in addition to the evaporation process, the operation investment of the pretreatment process of only removing SS in the present invention will save at least 50% than the process operation investment of two-stage precipitation and stripping to remove sulfide, SS, and inorganic ions, and the treatment time will also be reduced by at least 50%. 2/3.

Comparative example 6

COD _Cr concentration is 1520mg/L, Cl ^- content is 23292mg/L, and high-salt organic wastewater with pH=6.6 undergoes three-phase separation, precipitation softening, walnut shell filtration, and membrane distillation, and the COD in distilled water is 76mg/L, which has not reached If the distilled water COD is less than 60mg/L, the construction cost of a longer pretreatment device before distillation will be higher than that of the present invention, and the processing time will increase by more than 50%, and the cleaning and replacement of filter packing and membrane will also increase its operating cost by 20% Above, the whereabouts of concentrated water has not yet been considered.

The dosage of different oxidants, evaporation temperature, reaction time, and pH value are the direct factors affecting the generation of free radicals and the degradation efficiency of organic matter. Therefore, proper process combination, process condition selection and equipment improvement are the key to the treatment of high-salt volatile organic wastewater. Conventionally, the larger the dosage of oxidant, the higher the degradation efficiency of organic matter, but for the persulfate advanced oxidation technology in the present invention, too high dosage of persulfate will affect the generation of free radicals, thereby affecting the degradation of organic matter Efficiency, too low dosage will lead to rapid consumption of oxidant, incomplete oxidation of organic matter, resulting in a large amount of highly volatile small molecule organic matter, which will affect the quality of condensed water. Therefore, an appropriate amount of persulfate dosage is the key to the removal of organic matter.

The pH value will also affect the generation of free radicals. In addition, the types of free radicals generated by different pH values are different. Different types of free radicals have great differences in the oxidation efficiency of organic matter. the main reason. The invention realizes the generation of strong oxidizing free radicals by optimizing the dosage of persulfate and the pH value, ensures a high degradation rate of organic matter, and reduces the generation and overflow of volatile organic matter.

In the present invention, the high-salt volatile organic wastewater is pretreated, and the pretreated wastewater and acid-base regulator are pumped into the pipeline mixer to control the hydrogen ion concentration of the wastewater; the mixed liquid in the pipeline mixer is transported to the evaporation reactor , control the dosing method, evaporation temperature and evaporation time of persulfate; mix the evaporation steam and ozone through the condensing device and then connect it to the condensed water to degrade the volatile organic compounds for the second time; purify the tail gas after the reaction and then pass it into the evaporation reaction The distilled water after the reaction can be used as condensed water or discharged, and the concentrated water is crystallized to make salt.

The basic principles and main features of the present invention and the advantages of the present invention have been shown and described above. What the above-mentioned embodiments and description describe are only to illustrate the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention will also There are various changes and improvements which will fall within the scope of the claimed invention. The scope of the claimed invention is defined by the appended claims and their equivalents.

Claims (10)

1. A method for treating high-salt volatile organic wastewater is characterized by comprising the following steps: the method comprises the following steps:

(1) Preparing organic wastewater and raw materials, wherein SS in the organic wastewater is less than or equal to 10mg/L;

(2) Adding an acid regulator and an alkali regulator into the organic wastewater to form a mixed solution, wherein the pH value is 4-5;

(3) Adding persulfate, evaporating at 60-70 deg.c for 1.5-2.5 hr; COD in solution _Cr And S ₂ O ₈ ^2- The mass concentration ratio is 4-5, and the mass concentration of persulfate is 5%;

(4) Introducing ozone, and carrying out a condensation treatment step after mixing and reacting steam and ozone in the solution; the mass concentration of the ozone is 20-40 mg/L;

(5) And crystallizing the concentrated water to obtain the product.

2. The method for treating high-salinity volatile organic wastewater according to claim 1, wherein the method comprises the following steps: the acid regulator is HCl or sulfuric acid.

3. The method for treating high-salt volatile organic wastewater according to claim 1, characterized in that: the persulfate is one or more than two of sodium persulfate, potassium persulfate and ammonium persulfate.

4. A method for treating high-salinity volatile organic wastewater according to claim 1 or 3, characterized in that: the persulfate is sodium persulfate.

5. The method for treating high-salt volatile organic wastewater according to claim 1, characterized in that: the pH value in the step (2) is 5.

6. The method for treating high-salinity volatile organic wastewater according to claim 1, wherein the method comprises the following steps: the evaporation temperature is 60 ℃; the water conservancy residence time is 2 hours.

7. The method for treating high-salt volatile organic wastewater according to claim 1, characterized in that: the step (4) also comprises a tail gas recycling step, wherein the tail gas recycling step comprises the following steps: refluxing part of tail gas after reaction into the step (3) for recycling, and performing emission treatment on the tail gas meeting the emission conditions; the tail gas is a steam part which cannot be condensed; about 30 percent of tail gas reflows.

8. The utility model provides a handle high salt volatile organic waste water's system's device which characterized in that: comprises a wastewater tank (1), a wastewater pump (2), an acid liquid tank, a lye tank, an acid liquid pump, a lye pump, a pipeline mixer (5), a persulfate solution tank (6), a metering pump (7), an ozone generator (8), a blower (9), an evaporation reactor (10), a crystallization device (11), a condensing device (13) and a distilled water storage tank (14); the waste water tank (1) is connected with a waste water pump (2), the waste water pump (2) is connected with a pipeline mixer (5), the acid liquid tank is connected with an acid liquid pump, the alkali liquid tank is connected with an alkali liquid pump, the acid liquid pump and the alkali liquid pump are respectively connected with the pipeline mixer (5), and the pipeline mixer (5) is connected with an evaporation reactor (10); the persulfate solution tank (6) is connected with the metering pump (7), and the metering pump (7) is connected with the evaporation reactor (10); the crystallization device (11) is connected with the evaporation reactor (10), the ozone generator (8) is connected with the evaporation reactor (10) through a blower (9), the distilled water storage tank (14) is connected with the condensing device (13), and the condensing device (13) is connected with the evaporation reactor (10).

9. The system device for treating high-salinity wastewater according to claim 8, wherein: the system device is also provided with a wastewater pretreatment device (19), and the pretreatment device (19) is connected with the wastewater tank (1).

10. The system device for treating high-salinity wastewater according to claim 8, wherein: and a tail gas pipe (16) is also arranged, one end of the tail gas pipe (16) is connected with the distilled water storage tank (14), and the other end connecting point is arranged between the blower (9) and the evaporation reactor (10).

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