Continuous treatment and resource utilization process of high-oil wastewater

Abstract

The application discloses a kind of high oil wastewater continuous treatment and resourceization process, high oil wastewater and deionized water are input into reaction kettle, low-speed stirring is mixed, three-phase preliminary separation obtains oil phase, water phase and mixed phase, oil phase and mixed phase are treated by dehydration through thin film evaporator;Residue after dehydration is recovered with petroleum ether dynamic countercurrent extraction oil, extractant recycling is used, water phase is added surfactant and pH value is adjusted, PAC and CPAM are added to demulsification flocculation reaction, and the flocculation mixed solution is separated by plate and frame filter press, and the filtrate is introduced into the sewage treatment system, the sludge is dewatered, dried and crushed, and then transferred into the multistage petroleum ether extraction tower for dynamic countercurrent extraction with petroleum ether, and the residual oil is deeply recovered, and the recovered oil is vacuum dried and stored;The present application uses low-value high oil wastewater as the main raw material, and improves the process flow and changes the chemical additives to obtain high-quality regenerated oil, which is of great significance to the waste oil and high oil wastewater treatment industry.

Description

Technical Field

[0001] This invention relates to the fields of high-oil wastewater treatment and oil extraction technology, specifically to a low-speed chemical demulsification-driven green regeneration process for oils in high-oil wastewater, and more specifically to a continuous treatment and resource utilization process for high-oil wastewater. It uses low-speed synergistic demulsification technology as its core, and through a "precise emulsification-gradient demulsification-directional flocculation" system, achieves efficient recovery and resource utilization of regenerated oils. Background Technology

[0002] The resource utilization of waste cooking oil is an important direction for the circular economy and sustainable development. Waste cooking oil (UCO) refers to the large amounts of oily wastewater generated during food processing and catering, mainly originating from the catering industry, food processing industry, households, and industrial sectors. The resource utilization of high-oil wastewater demonstrates significant advantages in multiple aspects, including the environment, economy, energy, and society. Through standardized recycling and efficient treatment, high-oil wastewater is no longer an environmental burden but is transformed into a valuable resource.

[0003] Less than 10% of high-oil wastewater from catering establishments is properly recycled for biodiesel production. The remainder faces problems such as unclear destination and secondary pollution due to insufficient treatment technology. Currently, traditional high-oil wastewater treatment technologies generally suffer from low demulsification efficiency, high energy consumption, excessive addition of chemical agents (such as strong acids and alkalis), and solvent residues (petroleum ether single-stage extraction recovery rate <70%), resulting in high COD and large solid waste volume in the wastewater. This leads to large fluctuations in oil recovery rates and makes it difficult to achieve large-scale application.

[0004] By modifying the oil extraction process, a low-speed synergistic demulsification technology was developed. This technology significantly improves oil separation efficiency and reduces energy consumption by regulating molecular interface interactions and reagent compatibility. Summary of the Invention

[0005] To address the problems of high energy consumption, low recovery rate, and large solvent loss in existing high-oil wastewater treatment processes, this invention innovatively constructs an integrated process of aqueous phase demulsification, oil phase extraction, and solvent recycling, which significantly improves oil recovery efficiency and solvent utilization.

[0006] The technical solution of the present invention is as follows:

[0007] A continuous treatment and resource recovery process for high-oil wastewater includes the following steps:

[0008] (1) Add the high-oil wastewater and deionized water into the reactor and mix them at low speed;

[0009] (2) The mixture is separated into oil phase, water phase and mixed phase by a three-phase separator;

[0010] (3) The oil phase and mixed phase are dehydrated by a thin film evaporator to obtain evaporated water which is returned to step (1) for use.

[0011] (4) The residue after dehydration in step (3) is subjected to dynamic countercurrent extraction with petroleum ether in the extraction tower to recover the oil and the extract is recycled.

[0012] (5) Add surfactant to the aqueous phase of step (2) and stir for 3-5 minutes. After adjusting the pH to 5.5-6.0, add PAC (polyaluminum chloride) at 43-47℃ and stir for 15-20 minutes. After adjusting the pH to 6.5-7.5 while keeping the temperature constant, add CPAM (cationic polyacrylamide) and stir for 15-20 minutes to carry out demulsification and flocculation reaction.

[0013] (6) The flocculated mixed solution is separated into solid and liquid by plate and frame filter press. The filtrate enters the sewage treatment system. The dewatered sludge is dried and crushed and then transferred to the extraction tower for dynamic countercurrent extraction with petroleum ether to deeply recover residual oil.

[0014] (7) The oils recovered in steps (4) and (6) are dried in a vacuum drying tower at 55-65℃ and 10-30kPa and then stored.

[0015] In step (1), the mass ratio of high-oil wastewater to deionized water is 1:0.2-10.5.

[0016] In step (1), the speed of low-speed stirring is 55-65 rpm, and the stirring time is 10-15 minutes.

[0017] In step (3), the vacuum degree of the thin film evaporator is 250-320 mbar, the temperature is 85-95℃, and the processing time is controlled at 8-12 minutes.

[0018] The volume ratio of the dehydrated residue to petroleum ether in step (4) is 1:2-1:3.

[0019] In step (5), the surfactant is sodium dodecylbenzenesulfonate, with an addition amount of 0.5%; the addition amount of PAC is 0.5-1.5 g / L, and the addition amount of CPAM is 0.01-0.03 g / L; the demulsification and flocculation reaction takes 15-30 minutes, with the initial stage being rapid mixing at a speed of 120-130 rpm for 3-10 minutes, and the remaining time being slow flocculation at a speed of 40-50 rpm.

[0020] In steps (4) and (6), the temperature of the extraction tower is 40-60℃ and the number of stages is 3-5.

[0021] In steps (4) and (6), dynamic countercurrent extraction adopts a three-stage cross-flow mode.

[0022] In step (6), the volume ratio of dehydrated sludge dried product to petroleum ether is 1:2-1:3.

[0023] Step (6) The plate and frame filter press uses polyvinylidene fluoride membrane filter cloth, and the filtration accuracy reaches 5μm.

[0024] In step (7), the drying temperature of the vacuum drying tower is 55-65℃, and the absolute pressure is controlled at 10-30kPa.

[0025] The entire process of this invention is achieved through a DCS system, ensuring temperature deviation ≤ ±1℃, pH fluctuation ≤ ±0.2, and solvent recovery rate ≥ 90%.

[0026] The process of this invention has an overall recovery rate of ≥85%, and the energy consumption per ton of processing is reduced by 40-50% compared with the traditional process.

[0027] This invention innovatively constructs a multi-technology coupling system of "mechanical dehydration-solvent extraction-demulsification". Through the synergistic effect of thin-film evaporation and dynamic countercurrent extraction, the oil recovery rate is increased by more than 26% and the processing energy consumption is reduced by 40-50% compared with the traditional process.

[0028] This invention uses an intelligent DCS control system that integrates temperature interlock protection, pH feedforward adjustment, and precise reagent metering modules to achieve a process parameter fluctuation rate of ≤±2%, ensuring a reduction of more than 30% in the overall cost per ton of processing.

[0029] This invention pioneers a closed-loop petroleum ether recycling process, employing a three-stage recovery technology of countercurrent extraction, molecular sieve adsorption, and low-temperature condensation. Solvent consumption is reduced to below 0.8 kg / t, and operating costs are reduced by 60% compared to open systems.

[0030] This invention introduces an innovative aqueous phase cascade treatment process. Through pH-temperature dual-control demulsification and multi-stage extraction technology, the oil content of wastewater is reduced to ≤50mg / L, and the resource utilization rate reaches 85-92%.

[0031] This invention adopts a modular design and reduces the equipment footprint by 35% through process reengineering. It is particularly suitable for the continuous treatment of materials such as kitchen waste oil and grease chemical waste residue, and has significant environmental benefits and industrial application value. Attached Figure Description

[0032] Figure 1 This is an integrated diagram of the apparatus used in the process of this invention. Detailed Implementation

[0033] To make the technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments, but the scope of protection of the present invention is not limited to the described content. The raw materials used in the present invention can all be purchased commercially or obtained by conventional means.

[0034] Example 1

[0035] An apparatus for continuous treatment and resource recovery of high-oil wastewater, such as Figure 1 As shown, the high-oil wastewater tank and deionized water tank are both connected to the reactor. The reactor is connected to the three-phase separator. The top of the three-phase separator is connected to thin-film evaporator I, the middle of the three-phase separator is connected to thin-film evaporator II, and the bottom of the three-phase separator is connected to reaction tank I. The bottoms of thin-film evaporators I and II are connected to the deionized water tank. The middle of thin-film evaporators I and II is connected to extraction tower I. Extraction tower I is connected to oil storage tank and petroleum ether tank respectively. Oil storage tank and petroleum ether tank are also connected to extraction tower II respectively. Reaction tank I is connected to reaction tank II. Reaction tank II is connected to plate and frame filter press. Plate and frame filter press is also connected to sewage pipe and drying and pulverizing tower. Drying and pulverizing tower is connected to extraction tower II. All oils are stored in oil storage tank after being dried in vacuum drying tower. The intelligent DCS control system is connected to all the above components. The intelligent DCS control system integrates temperature interlock protection, pH feedforward adjustment, and precise reagent metering modules to achieve a process parameter fluctuation rate of ≤±2%.

[0036] Example 2

[0037] A continuous treatment and resource recovery process for high-oil wastewater, using the apparatus of Example 1, comprises the following specific steps:

[0038] (1) Taking the high oil wastewater from the kitchen with an oil content of 15.2wt%, moisture content of 82.4wt%, and impurities of 2.4wt% as an example, it is pumped into the reactor from the high oil wastewater tank and the deionized water tank respectively at a volume ratio of 1:0.5. The mixture is stirred at a low speed of 60rpm for 10 minutes in the reactor.

[0039] (2) After the reaction, the mixture is pumped into a three-phase separator, where it separates into oil, water and mixed phases.

[0040] The oil phase and the mixed phase were respectively introduced into thin film evaporator I and thin film evaporator II, and dehydrated for 10 minutes at 93°C and 300mbar. The evaporated water was returned to the deionized water tank in step (1). The water content of the residual oil after dehydration was measured to be reduced to 1.8%.

[0041] (3) The residue after dehydration is pumped into extraction tower I and subjected to dynamic countercurrent extraction with petroleum ether. The dehydrated oil and petroleum ether are subjected to three-stage dynamic countercurrent extraction at a volume ratio of 1:2. The extraction temperature is controlled at 40℃. The oil is recovered and the extract is recycled. The oil extraction rate is 94.3% as detected by gas chromatography. The residual solvent is recycled at a rate of 92.5% through the condensation recovery system.

[0042] (4) The aqueous phase from step (2) enters reaction tank I, and 0.5% of the aqueous phase mass of the surfactant sodium dodecylbenzenesulfonate is added and stirred for 4 minutes. After adjusting the pH to 5.8 with dilute hydrochloric acid using the pH automatic control unit, 0.6 g / L of PAC is added in a constant temperature environment of 45°C and stirred for 15 minutes. Then, the whole thing is pumped into reaction tank II. The pH is adjusted to 6.5 with sodium hydroxide solution while keeping the temperature constant, and then 0.02 g / L of CPAM is added to carry out demulsification and flocculation reaction. The reaction is stirred for 15 minutes. The first part is rapidly mixed at a speed of 120 rpm for 3 minutes, and the remaining time is spent slowly flocculating at a speed of 40 rpm. The demulsification efficiency is 89.7% as measured by the Zeta potentiometer.

[0043] (5) The flocculated mixture is separated by a plate and frame filter press at 0.5MPa. The filtrate is fed into the sewage pipe and the residual oil content is reduced to 48mg / L. After the dewatered sludge is dried and crushed, it is transferred to the extraction tower II for dynamic countercurrent extraction with petroleum ether. The dewatered sludge and petroleum ether are subjected to three-stage dynamic countercurrent extraction at a volume ratio of 1:2. The extraction temperature is controlled at 40℃ to deeply recover residual oil.

[0044] (6) The oils recovered in steps (3) and (5) are dried in a vacuum drying tower at 60℃ and 20kPa and then stored in an oil storage tower. The moisture content is ≤0.3% and the acid value is ≤1.2mgKOH / g, which meets the GB2716-2018 standard.

[0045] In this embodiment, the overall energy consumption per ton of processing is reduced by 43.6% compared with the traditional process, the solvent consumption is 0.78 kg / t, and the overall oil recovery rate is 87.2%.

[0046] Example 3

[0047] A continuous treatment and resource recovery process for high-oil wastewater, using the apparatus of Example 1, comprises the following specific steps:

[0048] (1) Taking the oily wastewater of oleochemical industry with an oil content of 10.1wt%, moisture of 86.5wt%, and impurities of 3.4wt% as an example, it is pumped into the reaction vessel from the oily wastewater pool and the deionized water tank at a volume ratio of 1:0.3, and mixed at a low speed of 55rpm for 15 minutes in the reaction vessel.

[0049] (2) After the reaction, the mixture is pumped into a three-phase separator, where it separates into oil, water and mixed phases.

[0050] The oil phase and the mixed phase were respectively introduced into thin film evaporator I and thin film evaporator II, and dehydrated for 10 minutes at 90℃ and 250mbar. The evaporated water was returned to the deionized water tank in step (1). The water content of the residual oil after dehydration was measured to be reduced to 1.7%.

[0051] (3) The residue after dehydration is pumped into extraction tower I and subjected to dynamic countercurrent extraction with petroleum ether. The dehydrated oil and petroleum ether are subjected to three-stage dynamic countercurrent extraction at a volume ratio of 1:2.5. The extraction temperature is controlled at 45℃. The oil is recovered and the extract is recycled. The oil extraction rate is 92.5% as detected by gas chromatography. The residual solvent is recycled at a rate of 90.8% through the condensation recovery system.

[0052] (4) The aqueous phase from step (2) enters reaction tank I, and 0.5% of the aqueous phase mass of the surfactant sodium dodecylbenzenesulfonate is added and stirred for 5 minutes. After adjusting the pH to 5.8 with dilute hydrochloric acid using the pH automatic control unit, 0.6 g / L of PAC is added in a constant temperature environment of 45℃ and stirred for 16 minutes. Then, the whole thing is pumped into reaction tank II. The pH is adjusted to 6.5 with sodium hydroxide solution while keeping the temperature constant, and then 0.02 g / L of CPAM is added to carry out demulsification and flocculation reaction. The reaction is stirred for 20 minutes. The first part is rapidly mixed at a speed of 120 rpm for 5 minutes, and the remaining time is slowly flocculated at a speed of 40 rpm. The demulsification efficiency is 89.7% as measured by the Zeta potentiometer.

[0053] (5) The flocculated mixture is separated by a plate and frame filter press at 0.6MPa. The filtrate is fed into the sewage pipe and the residual oil content is reduced to 42mg / L. After the dewatered sludge is dried and crushed, it is transferred to the extraction tower II for dynamic countercurrent extraction with petroleum ether. The dewatered sludge and petroleum ether are subjected to three-stage dynamic countercurrent extraction at a volume ratio of 1:2. The extraction temperature is controlled at 40℃ to deeply recover residual oil.

[0054] (6) The oils recovered in steps (3) and (5) are dried in a vacuum drying tower at 60℃ and 20kPa and then stored in an oil storage tower. The moisture content is ≤0.3% and the acid value is ≤1.0mgKOH / g, which meets the GB2716-2018 standard.

[0055] In this embodiment, the overall energy consumption per ton of processing is reduced by 47.2% compared with the traditional process, the solvent consumption is 0.74 kg / t, and the overall oil recovery rate is 87.9%.

[0056] Example 4

[0057] A continuous treatment and resource recovery process for high-oil wastewater, using the apparatus of Example 1, comprises the following specific steps:

[0058] (1) Taking biodiesel high oil wastewater with an oil content of 9.8wt%, moisture content of 88.7wt%, and impurities of 1.5wt% as an example, it is pumped into the reaction vessel from the high oil wastewater pool and the deionized water tank respectively at a volume ratio of 1:0.2. The mixture is stirred at a low speed of 60rpm for 10 minutes in the reaction vessel.

[0059] (2) After the reaction, the mixture is pumped into a three-phase separator, where it separates into oil, water and mixed phases.

[0060] The oil phase and the mixed phase were respectively introduced into thin film evaporator I and thin film evaporator II, and dehydrated for 8 minutes at 95°C and 320mbar. The evaporated water was returned to the deionized water tank in step (1). The water content of the residual oil after dehydration was measured to be reduced to 0.8%.

[0061] (3) The residue after dehydration is pumped into extraction tower I and subjected to dynamic countercurrent extraction with petroleum ether. The dehydrated oil and petroleum ether are subjected to three-stage dynamic countercurrent extraction at a volume ratio of 1:2.5. The extraction temperature is controlled at 45℃. The oil is recovered and the extract is recycled. The oil extraction rate is 93.1% as detected by gas chromatography. The residual solvent is recycled at a rate of 92.2% through the condensation recovery system.

[0062] (4) The aqueous phase from step (2) enters reaction tank I, and 0.5% of the aqueous phase mass of the surfactant sodium dodecylbenzenesulfonate is added and stirred for 3 minutes. After adjusting the pH to 6 with dilute hydrochloric acid by the pH automatic control unit, 0.5 g / L of PAC is added in a constant temperature environment of 45°C and stirred for 18 minutes. Then, the whole thing is pumped into reaction tank II. After adjusting the pH to 7 with sodium hydroxide solution while keeping the temperature constant, 0.018 g / L of CPAM is added to carry out demulsification and flocculation reaction. The reaction is stirred for 30 minutes. The first part is rapidly mixed at a speed of 125 rpm for 10 minutes, and the remaining time is slowly flocculated at a speed of 45 rpm. The demulsification efficiency is 92.1% as measured by the Zeta potentiometer.

[0063] (5) The flocculated mixture is separated by a plate and frame filter press at 0.6MPa. The filtrate is fed into the sewage pipe and the residual oil content is reduced to 35mg / L. After the dewatered sludge is dried and crushed, it is transferred to the extraction tower II for dynamic countercurrent extraction with petroleum ether. The dewatered sludge and petroleum ether are subjected to three-stage dynamic countercurrent extraction at a volume ratio of 1:2. The extraction temperature is controlled at 60℃ to deeply recover residual oil.

[0064] (6) The oils recovered in steps (3) and (5) are dried in a vacuum drying tower at 60℃ and 20kPa and then stored in an oil storage tower. The moisture content is ≤0.4% and the acid value is ≤0.9mgKOH / g, which meets the GB2716-2018 standard.

[0065] In this embodiment, the overall energy consumption per ton of processing is reduced by 47.3% compared with the traditional process, the solvent consumption is 0.65 kg / t, and the overall oil recovery rate is 90.2%.

[0066] Example 5

[0067] A continuous treatment and resource recovery process for high-oil wastewater, using the apparatus of Example 1, comprises the following specific steps:

[0068] (1) Taking the high oil wastewater from the slaughterhouse with an oil content of 15.6wt%, moisture content of 80.3wt%, and impurities of 4.1wt% as an example, it was pumped into the reaction vessel from the high oil wastewater pool and the deionized water tank respectively at a volume ratio of 1:0.5. The mixture was stirred at a low speed of 60rpm for 12 minutes in the reaction vessel.

[0069] (2) After the reaction, the mixture is pumped into a three-phase separator, where it separates into oil, water and mixed phases.

[0070] The oil phase and the mixed phase were respectively introduced into thin film evaporator I and thin film evaporator II, and dehydrated for 12 minutes at 85°C and 250mbar. The evaporated water was returned to the deionized water tank in step (1). The water content of the residual oil after dehydration was measured to be reduced to 2.1%.

[0071] (3) The residue after dehydration is pumped into extraction tower I and subjected to dynamic countercurrent extraction with petroleum ether. The dehydrated oil and petroleum ether are subjected to three-stage dynamic countercurrent extraction at a volume ratio of 1:3. The extraction temperature is controlled at 40℃. The oil is recovered and the extract is recycled. The oil extraction rate is 91.5% as detected by gas chromatography. The residual solvent is recycled by the condensation recovery system with a recycling rate of 90.3%.

[0072] (4) The aqueous phase from step (2) enters reaction tank I, and 0.5% of the aqueous phase mass of the surfactant sodium dodecylbenzenesulfonate is added and stirred for 3 minutes. After adjusting the pH to 6 with dilute hydrochloric acid using the pH automatic control unit, 0.8 g / L of PAC is added in a constant temperature environment of 45°C and stirred for 20 minutes. Then, the whole thing is pumped into reaction tank II. The temperature is kept constant and the pH is adjusted to 7.5 with sodium hydroxide solution. Then, 0.03 g / L of CPAM is added to carry out demulsification and flocculation reaction. The reaction is stirred for 20 minutes. The first part is rapidly mixed at a speed of 130 rpm for 6 minutes, and the remaining time is slowly flocculated at a speed of 50 rpm. The demulsification efficiency is 87.9% as measured by the Zeta potentiometer.

[0073] (5) The flocculated mixture is separated by a plate and frame filter press at 0.5MPa. The filtrate is fed into the sewage pipe and the residual oil content is reduced to 55mg / L. After the dewatered sludge is dried and crushed, it is transferred to the extraction tower II for dynamic countercurrent extraction with petroleum ether. The dewatered sludge and petroleum ether are subjected to three-stage dynamic countercurrent extraction at a volume ratio of 1:2.5. The extraction temperature is controlled at 50℃ to deeply recover residual oil.

[0074] (6) The oils recovered in steps (3) and (5) are dried in a vacuum drying tower at 60℃ and 20kPa and then stored in an oil storage tower. The moisture content is ≤0.6% and the acid value is ≤1.5mgKOH / g, which meets the GB2716-2018 standard.

[0075] In this embodiment, the overall energy consumption per ton of processing is reduced by 41.8% compared with the traditional process, the solvent consumption is 0.74 kg / t, and the overall oil recovery rate is 85.6%.

[0076] Example 6

[0077] A continuous treatment and resource recovery process for high-oil wastewater, using the apparatus of Example 1, comprises the following specific steps:

[0078] (1) Taking the high-oil wastewater of refinery waste clay with an oil content of 7.3wt%, moisture content of 91.2wt%, and impurities of 1.5wt% as an example, it was pumped into the reactor from the high-oil wastewater pool and the deionized water tank respectively at a volume ratio of 1:0.3. The mixture was stirred at a low speed of 65rpm for 10 minutes in the reactor.

[0079] (2) After the reaction, the mixture is pumped into a three-phase separator, where it separates into oil, water and mixed phases.

[0080] The oil phase and the mixed phase were respectively fed into thin film evaporator I and thin film evaporator II, and dehydrated at 90°C and 300mbar. The evaporated water was returned to the deionized water tank in step (1). The water content of the residual oil after dehydration was measured to be reduced to 1.8%.

[0081] (3) The residue after dehydration is pumped into extraction tower I and subjected to dynamic countercurrent extraction with petroleum ether. The dehydrated oil and petroleum ether are subjected to three-stage dynamic countercurrent extraction at a volume ratio of 1:2. The extraction temperature is controlled at 60℃. The oil is recovered and the extract is recycled. The oil extraction rate is 93.2% as determined by gas chromatography. The residual solvent is recycled at a rate of 92.5% through the condensation recovery system.

[0082] (4) The aqueous phase from step (2) enters reaction tank I, and 0.5% of the aqueous phase mass of the surfactant sodium dodecylbenzenesulfonate is added and stirred for 4 minutes. After adjusting the pH to 5.5 with dilute hydrochloric acid using the pH automatic control unit, 0.55 g / L of PAC is added in a constant temperature environment of 45°C and stirred for 16 minutes. Then, the whole thing is pumped into reaction tank II. The pH is adjusted to 6.5 with sodium hydroxide solution while keeping the temperature constant, and then 0.022 g / L of CPAM is added to carry out demulsification and flocculation reaction. The reaction is stirred for 15 minutes. The first part is rapidly mixed at a speed of 120 rpm for 3 minutes, and the remaining time is spent slowly flocculating at a speed of 40 rpm. The demulsification efficiency is 92.3% as measured by the Zeta potentiometer.

[0083] (5) The flocculated mixture is separated by a plate and frame filter press at 0.6MPa. The filtrate is fed into the sewage pipe and the residual oil content is reduced to 28mg / L. After the dewatered sludge is dried and crushed, it is transferred to the extraction tower II for dynamic countercurrent extraction with petroleum ether. The dewatered sludge and petroleum ether are subjected to three-stage dynamic countercurrent extraction at a volume ratio of 1:3. The extraction temperature is controlled at 40℃ to deeply recover residual oil.

[0084] (6) The oils recovered in steps (3) and (5) are dried in a vacuum drying tower at 60℃ and 20kPa and then stored in an oil storage tower. The moisture content is ≤0.5% and the acid value is ≤0.8mgKOH / g, which meets the GB2716-2018 standard.

[0085] In this embodiment, the overall energy consumption per ton of processing is reduced by 48.7% compared with the traditional process, the solvent consumption is 0.58 kg / t, and the overall oil recovery rate is 91.5%.

[0086] The above description is only a part of the embodiments of the present invention, and not all of the embodiments. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be covered within the scope of the claims of the present invention.

Claims

1. A continuous treatment and resource recovery process for high-oil wastewater, characterized in that, The specific steps are as follows: (1) Add the high-oil wastewater and deionized water into the reactor and mix them at low speed; (2) The mixture is separated into oil phase, water phase and mixed phase by a three-phase separator; (3) The oil phase and mixed phase are dehydrated by a thin film evaporator to obtain evaporated water which is returned to step (1) for use. (4) The residue after dehydration in step (3) is subjected to dynamic countercurrent extraction with petroleum ether in the extraction tower to recover the oil and the extract is recycled. (5) Add surfactant to the aqueous phase of step (2) and stir for 3-5 minutes. After adjusting the pH to 5.5-6.0, add PAC at 43-47℃ and stir for 15-20 minutes. After adjusting the pH to 6.5-7.5 while keeping the temperature constant, add CPAM and stir for 15-20 minutes to carry out demulsification and flocculation reaction. (6) The flocculated mixed solution is separated into solid and liquid by plate and frame filter press. The filtrate enters the sewage treatment system. The dewatered sludge is dried and crushed and then transferred to the extraction tower for dynamic countercurrent extraction with petroleum ether to deeply recover residual oil. (7) The oils recovered in steps (4) and (6) are dried under vacuum at 55-65℃ and 10-30kPa and then stored.

2. The continuous treatment and resource recovery process for high-oil wastewater according to claim 1, characterized in that, In step (1), the mass ratio of high-oil wastewater to deionized water is 1:0.2-0.

5.

3. The continuous treatment and resource recovery process for high-oil wastewater according to claim 1, characterized in that, In step (1), the speed of low-speed stirring is 55-65 rpm, and the stirring time is 10-15 minutes.

4. The continuous treatment and resource recovery process for high-oil wastewater according to claim 1, characterized in that, In step (3), the vacuum degree of the thin film evaporator is 250-320 mbar, the temperature is 85-95℃, and the processing time is controlled at 8-12 minutes.

5. The continuous treatment and resource recovery process for high-oil wastewater according to claim 1, characterized in that, In step (5), the surfactant is sodium dodecylbenzenesulfonate, and the amount added is 0.5%; the amount added of PAC is 0.5-1.5 g / L, and the amount added of CPAM is 0.01-0.03 g / L.

6. The continuous treatment and resource recovery process for high-oil wastewater according to claim 1, characterized in that, In step (5), the demulsification and flocculation reaction takes 15-30 minutes. The first part is rapidly mixed at 120-130 rpm for 3-10 minutes, and the remaining time is spent slowly flocculating at 40-50 rpm.

7. The continuous treatment and resource recovery process for high-oil wastewater according to claim 1, characterized in that, In steps (4) and (6), the temperature of the extraction tower is 40-60℃ and the number of stages is 3-5.

8. The continuous treatment and resource recovery process for high-oil wastewater according to claim 1, characterized in that, In step (4), the volume ratio of the dehydrated residue to petroleum ether is 1:2-1:3; in step (6), the volume ratio of the dehydrated sludge dried product to petroleum ether is 1:2-1:

3.

9. The continuous treatment and resource recovery process for high-oil wastewater according to claim 1, characterized in that, In steps (4) and (6), dynamic countercurrent extraction adopts a three-stage cross-flow mode.

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