A heat pump temperature control type plasma and Fenton oxidation combined graded organic wastewater treatment system and method

Abstract

The application discloses a heat pump temperature control type plasma and Fenton oxidation grading organic wastewater treatment system and method, which comprises a first water pump, a plasma bubbling water treatment reactor, a Fenton-like oxidation reactor, a gas pump, a high-voltage power supply, an evaporator, a first condenser, a compressor and a second condenser; by coupling Fenton reaction and realizing temperature control, after plasma advanced oxidation reaction, low-temperature plasma heat energy and low-potential active oxidant H2O2 are efficiently utilized to realize organic matter oxidation degradation of water body, and precise temperature control of each stage of wastewater oxidation is realized to facilitate to reach the best temperature; the addition of Fenton-like oxidation fillers on the porous catalyst carrier plate makes the divalent iron Fe 2+ in the particles to participate in Fenton oxidation reaction with H2O2 to generate trivalent iron Fe 3+ and strong oxidizing ·OH to participate in organic matter degradation, and meanwhile, temperature control makes the sensible heat in the wastewater, the electric heat provided by the plasma and the chemical reaction heat in the plasma oxidation process to be utilized, which is favorable for realizing efficient degradation of industrial organic wastewater.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of organic wastewater treatment, in particular to a heat pump temperature control type plasma collaborative Fenton oxidation graded organic wastewater treatment system and method. BACKGROUND

[0002] Industrial organic wastewater is widely produced in the industries of printing and dyeing, chemical industry, papermaking and pharmaceutical industry, and the organic pollutants contained therein have the characteristics of resisting photolysis, oxidation and biodegradation, and thus it is urgent to develop a suitable organic wastewater advanced oxidation technology, i.e. low-temperature plasma advanced oxidation method, as a new emerging water treatment technology which is green and environmentally friendly, has the advantages of non-selectivity of organic matter degradation, renewable green electricity driving and continuous deep treatment, and has great development potential in the market of industrial wastewater treatment containing refractory organic matter. The low-temperature plasma advanced oxidation technology mainly generates plasma by exciting gas through high voltage, and the high-energy electrons in the plasma generate oxidizing active particles (·OH, ·O2 - , O3, H2O2) at the liquid interface to participate in the degradation of organic pollutants in water. However, the energy efficiency of the low-temperature plasma water treatment system in degrading organic pollutants still needs to be improved.

[0003] Combining the low-temperature plasma technology with the Fenton oxidation technology to construct a composite advanced oxidation technology is helpful to improve the energy efficiency of the low-temperature plasma in degrading organic wastewater. In the process of treating organic wastewater, the plasma degrades the organic pollutants while generating a certain concentration of H2O2 as a raw material for Fenton oxidation reaction, and the pH of the organic wastewater is reduced to about 2-3 which is suitable for Fenton oxidation reaction. However, the suitable reaction temperatures of the low-temperature plasma bubbling reaction and the Fenton oxidation reaction are different, and the current integrated system of low-temperature plasma coupled with Fenton oxidation is difficult to control the temperature. In addition, the temperature of the discharged industrial organic wastewater is usually high, for example, the temperature of the printing and dyeing wastewater is 40-90℃, the temperature of the discharged papermaking wastewater can reach 40-60℃, and the temperature of the discharged petrochemical wastewater can reach 60℃, which are not suitable temperatures for the plasma bubble oxidation reaction. SUMMARY

[0004] In view of the above technical problems, the purpose of the present application is to provide a heat pump temperature control type plasma collaborative Fenton oxidation graded organic wastewater treatment system and method, which can optimize the reaction temperature conditions and improve the efficiency of the advanced oxidation of organic wastewater by constructing a low-temperature plasma oxidation-Fenton oxidation graded reaction and matching a heat pump temperature control device. By introducing the heat pump temperature control device, the temperature control of the plasma oxidation-Fenton oxidation reactor and the recovery of the waste heat of the inlet water can be realized, which can help the efficient degradation of industrial organic wastewater.

[0005] The technical solution of the present application is as follows:

[0006] The application discloses a heat pump temperature control type plasma collaborative Fenton oxidation grading organic wastewater treatment system, which comprises a first water pump, a plasma bubble water treatment reactor, a Fenton-like oxidation reactor, a gas pump, a high-voltage power supply and a heat pump temperature control device.

[0007] The first water pump is connected with one end of the evaporator, and the other end of the evaporator is connected with a first water inlet of the plasma bubble water treatment reactor; a water outlet of the plasma bubble water treatment reactor is connected with one end of the first condenser, and the other end of the first condenser is connected with a water inlet of the Fenton-like oxidation reactor; a first water outlet is arranged in the middle of the Fenton-like oxidation reactor, and a second water outlet is arranged at the bottom of the Fenton-like oxidation reactor; one end of the second water outlet is connected with one end of a second water pump, and the other end of the second water pump is connected with a second water inlet of the plasma bubble water treatment reactor.

[0008] The working medium outlet of the evaporator is connected with one end of the compressor through a pipeline, the other end of the compressor is connected with one end of the second condenser through a pipeline, the other end of the second condenser is connected with the working medium inlet of the first condenser through a pipeline, and the working medium outlet of the first condenser is connected with the working medium inlet of the evaporator through a pipeline; the working medium inlet of the second condenser is connected with a treatment water inlet, and the working medium outlet of the second condenser is connected with a treatment water outlet.

[0009] One end of the gas pump is connected with a stainless steel aeration pipe at the bottom of the plasma bubble water treatment reactor, and the stainless steel aeration pipe is connected with the high-voltage power supply; and the top of the plasma bubble water treatment reactor is provided with a gas outlet.

[0010] In the scheme, the organic wastewater is driven by the first water pump to flow through the evaporator, is cooled to a preset temperature of plasma bubble oxidation reaction by a low-temperature heat pump working medium, and then flows into the plasma bubble water treatment reactor.

[0011] The gas is driven by the gas pump to enter the stainless steel aeration pipe connected with the high-voltage power supply, is treated by the plasma bubble water treatment reactor, and then the organic wastewater is degraded to produce H2O2, a raw material of Fenton oxidation reaction, and the pH of the organic wastewater is reduced; the organic wastewater flows out of the water outlet of the plasma bubble water treatment reactor, is heated to a preset temperature by a high-temperature heat pump working medium after flowing through the first condenser, and then flows into the Fenton-like oxidation reactor to perform Fenton oxidation reaction; the reacted organic wastewater is driven by the circulating second water pump to flow back to the plasma bubble water treatment reactor to perform a circulating reaction; and the treatment water flows out of the water outlet after the reaction is completed.

[0012] In the scheme, a stop valve is arranged on the connecting pipeline between the working medium outlet of the first condenser and the working medium inlet of the evaporator.

[0013] In the scheme, a grounding electrode is arranged in the plasma bubble water treatment reactor.

[0014] In the above scheme, the Fenton-like oxidation reactor comprises a water inlet spray head, Fenton-like oxidation filler, and a porous catalyst carrier plate.

[0015] A plurality of water inlet spray heads are uniformly arranged in the upper part of the Fenton-like oxidation reactor, and a plurality of layers of Fenton-like oxidation filler are arranged below the plurality of water inlet spray heads, and each layer of Fenton-like oxidation filler is uniformly placed on the porous catalyst carrier plate; the hole size of the porous catalyst carrier plate is smaller than the diameter of the Fenton-like oxidation filler.

[0016] In the above scheme, a three-way valve is arranged on the connecting pipeline between the second water pump and the plasma bubbling water treatment reactor.

[0017] A method for treating organic wastewater by using the heat pump temperature control type plasma and Fenton-like oxidation combined graded organic wastewater treatment system, comprising the following steps:

[0018] Step S1, the organic wastewater to be degraded is pumped into the plasma bubbling water treatment reactor through the evaporator by the first water pump;

[0019] Step S2, the oxygen-containing gas enters the stainless steel aeration pipe through the gas pump, the plasma power connected to the stainless steel aeration pipe of the high-voltage electrode is adjusted to the discharge power, and under the driving of the high voltage between the stainless steel aeration pipe and the grounding electrode, the gas is excited to plasma in the stainless steel aeration pipe and bubbles into the organic wastewater to degrade the organic pollutants;

[0020] Step S3, the treated liquid after low-temperature plasma degradation flows out of the reactor under the driving of the liquid level pressure in the low-temperature plasma reactor, and then flows into the Fenton-like oxidation reactor after passing through the second condenser;

[0021] Step S4, the treated liquid flowing into the Fenton-like oxidation reactor is first uniformly sprayed on the porous catalyst carrier plate uniformly placed with Fenton-like oxidation filler through the water inlet spray head, and penetrates layer by layer to realize Fenton reaction and oxidize and degrade the organic matter in the wastewater;

[0022] Step S5, the treated liquid after degradation in the Fenton-like oxidation reactor is discharged through the water outlet, and the pH, conductivity and COD of the treated liquid are measured at the water outlet;

[0023] Step S6, the measurement results are compared with the national standard to determine whether the treated liquid meets the discharge standard, and if it meets the standard, the treatment is completed; if it does not meet the standard, the wastewater in the Fenton-like oxidation reactor is continuously pumped into the plasma bubbling water treatment reactor by the second water pump for recycling treatment.

[0024] In the above scheme, the organic wastewater is cooled to a temperature of 15-30℃ for plasma bubble oxidation reaction by the low-temperature heat pump working medium through the evaporator driven by the first water pump, and then flows into the plasma bubbling water treatment reactor.

[0025] The gas is driven by the air pump into the stainless steel aeration pipe connected with the high-voltage power supply, and after being treated by the plasma bubble water treatment reactor, the organic wastewater is degraded of the organic pollutants, and H2O2, the raw material of Fenton oxidation reaction, is generated at the same time, and the pH of the organic wastewater is reduced to 2-3, which is more suitable for Fenton oxidation reaction; then the organic wastewater flows through the first condenser and is heated to 50-70 DEG C by the high-temperature heat pump working medium, and then flows into the Fenton-like oxidation reactor for Fenton oxidation reaction.

[0026] In the above scheme, the low-temperature working medium of -10-10 DEG C in the evaporator of the heat pump system exchanges heat with the organic wastewater with a temperature of 30-80 DEG C, so that the temperature of the organic wastewater is reduced to 15-30 DEG C which is suitable for the plasma bubble oxidation reaction, the temperature of the working medium at the outlet of the evaporator is increased to 80-140 DEG C after being compressed and working in the compressor, and in the second condenser, the high-temperature working medium transfers heat to the industrial or domestic water, and the outlet water reaches a hot water temperature of 80-100 DEG C, and the working medium after being cooled heats the inlet water of the Fenton-like oxidation reactor to 50-70 DEG C in the first condenser.

[0027] In the above scheme, the Fenton-like oxidation filler is Fe-N-C Fenton catalytic material which is synthesized by Enteromorpha prolifera and Fe(NO3)3·9H2O.

[0028] The synthesis method of the Fe-N-C Fenton catalytic material is as follows: after being crushed, Enteromorpha prolifera with a particle size of 160-250 mu m is dried at 105 DEG C for 24 h to remove water, and a dried sample active biochar is obtained; the dried sample is pyrolyzed at 500 DEG C under the flow of N2 with a flow rate of 200 mL / min at a rate of 5 DEG C / min for 1 h, then KOH is added, and the mass ratio of the active biochar to KOH is 2:1 to increase the porosity; then the pyrolysis is further carried out at 800 DEG C under the flow of N2 with a flow rate of 200 mL / min at a rate of 5 DEG C / min for 1 h, then the obtained powder is washed with deionized water until neutral, and the obtained powder is dried at 105 DEG C for 24 h to obtain algal-based active biochar; the algal-based active biochar is mixed with Fe(NO3)3·9H2O and deionized water in a mass ratio of 100:1:600, stirred for 2 h, and then placed in an 80 DEG C oven for drying, and finally pyrolyzed at 500 DEG C under the flow of N2 with a flow rate of 200 mL / min at a rate of 5 DEG C / min for 3 h to obtain the final product Fe-N-C Fenton catalytic material.

[0029] Compared with the prior art, the present application has the following technical effects:

[0030] This invention enables the efficient utilization of low-temperature plasma thermal energy and low-potential active oxide H2O2 to oxidize and degrade organic matter in a heat pump temperature-controlled plasma-coordinated Fenton oxidation staged organic wastewater treatment system. This is achieved by coupling the Fenton reaction and controlling the temperature after the advanced plasma oxidation reaction, while precisely controlling the temperature at each stage of wastewater oxidation to reach the optimal level. The addition of Fenton-like oxidation packing material on the porous catalyst support plate reduces the amount of ferrous iron (Fe²⁺) in the particles. 2+ It undergoes Fenton oxidation with H2O2 to produce ferric iron (Fe). 3+ The strong oxidizing ·OH participates in the degradation of organic matter. At the same time, the introduction of temperature control allows the sensible heat in the wastewater, the electrothermal heat provided by the plasma, and the heat of chemical reaction during the plasma oxidation process to be utilized, which is conducive to achieving the optimal oxidation temperature at each stage to realize the efficient degradation of industrial organic wastewater.

[0031] The heat pump temperature-controlled plasma-coordinated Fenton oxidation staged organic wastewater treatment system and method provided by this invention can effectively improve the energy efficiency of low-temperature plasma advanced oxidation and the degradation efficiency of organic wastewater, providing an effective technical solution for energy-saving transformation and optimization of low-temperature plasma organic wastewater treatment systems. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the heat pump temperature-controlled plasma-assisted Fenton oxidation staged organic wastewater treatment system of the present invention.

[0033] Figure 2 This is a graph showing the degradation rate of staged organic wastewater by heat pump temperature-controlled plasma synergistic Fenton oxidation according to the present invention.

[0034] Figure 3 This is a pH diagram of the degradation of organic wastewater by heat pump temperature-controlled plasma-assisted Fenton oxidation staged organic wastewater according to the present invention.

[0035] Figure 4 The diagram shows the degradation energy efficiency of the heat pump temperature-controlled plasma-assisted Fenton oxidation staged organic wastewater when the degradation rate is 50%.

[0036] The markings in the diagram are as follows: 1—Organic wastewater; 2—First water pump; 3—Evaporator; 4—Plasma bubbling water treatment reactor; 5—Second condenser; 6—Fenton-like oxidation reactor; 7—Steam turbine; 8—First condenser; 9—Stop valve; 10—Oxygen-containing gas; 11—Air pump; 12—Stainless steel aeration pipe; 13—Plasma power supply; 14—Grounding electrode; 15—Low-temperature plasma bubbles; 16—Organic wastewater after plasma degradation; 17—Air outlet; 18—Spray head; 19—Fenton-like oxidation packing; 20—Porous catalyst support plate; 21—Second water pump; 22—Three-way valve; 23—Water outlet; 24—Industrial and domestic hot water; 25—Hot water outlet. DETAILED DESCRIPTION

[0037] Embodiments of the present application are described below in detail,

[0038] Embodiments of the present application are described below in detail, examples of which are shown in the accompanying drawings, wherein the same or similar reference signs represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by reference to the drawings are exemplary and are intended to explain the present application, and cannot be understood as a limitation of the present application.

[0039] Embodiment 1

[0040] A heat pump temperature control type plasma synergistic Fenton oxidation staged organic wastewater treatment system, comprising a first water pump 2, a plasma bubbling water treatment reactor 4, a Fenton-like oxidation reactor 6, an air pump 11, a high-voltage power supply 13 and a heat pump temperature control device; the heat pump temperature control device comprises an evaporator 3, a first condenser 5, a compressor 7 and a second condenser 8;

[0041] The first water pump 2 is connected with one end of the evaporator 3, and the other end of the evaporator 3 is connected with a first water inlet of the plasma bubbling water treatment reactor 4; a water outlet of the plasma bubbling water treatment reactor 4 is connected with one end of the first condenser 5, and the other end of the first condenser 5 is connected with a water inlet of the Fenton-like oxidation reactor 6; a first water outlet is arranged in the middle of the Fenton-like oxidation reactor 6, and a second water outlet is arranged at the bottom, the second water outlet is connected with one end of a second water pump 21, and the other end of the second water pump 21 is connected with a second water inlet of the plasma bubbling water treatment reactor 4;

[0042] The working medium outlet of the evaporator 3 is connected with one end of the compressor 7 through a pipeline, the other end of the compressor 7 is connected with one end of the second condenser 8 through a pipeline, the other end of the second condenser 8 is connected with the working medium inlet of the first condenser 5 through a pipeline, and the working medium outlet of the first condenser 5 is connected with the working medium inlet of the evaporator 3 through a pipeline; the working medium inlet of the second condenser 8 is connected with a treatment water inlet, and the working medium outlet of the second condenser 8 is connected with a treatment water outlet;

[0043] One end of the air pump 11 is connected with a stainless steel aeration pipe 12 at the bottom of the plasma bubbling water treatment reactor 4, and the stainless steel aeration pipe 12 is connected with the high-voltage power supply 13; an air outlet 17 is arranged at the top of the plasma bubbling water treatment reactor 4.

[0044] The organic wastewater 1 is driven by the first water pump 2 to flow through the evaporator 3 and is cooled to a preset temperature of the plasma bubble oxidation reaction by the low-temperature heat pump working medium, and then flows into the plasma bubbling water treatment reactor 4.

[0045] The gas 10 is driven by the air pump 11 into the stainless steel aeration pipe 12 connected to the high-voltage power supply 13, and after being treated by the plasma bubbling water treatment reactor 4, the organic wastewater 16 is degraded in the organic pollutants, and the Fenton oxidation reaction raw material H2O2 is generated at the same time, and the pH of the organic wastewater 16 is reduced. The organic wastewater 16 flows out of the water outlet of the plasma bubbling water treatment reactor 4, is heated to a preset temperature by the high-temperature heat pump working medium through the first condenser 5, and then flows into the Fenton-like oxidation reactor 6 to carry out the Fenton oxidation reaction. The reacted organic wastewater is driven by the circulating second water pump 21 to flow back to the plasma bubbling water treatment reactor 4 for circulating reaction; and after the reaction is completed, the treated water flows out through the water outlet 23.

[0046] A stop valve 9 is arranged on the connecting pipeline between the working medium outlet of the first condenser 5 and the working medium inlet of the evaporator 3.

[0047] The plasma bubbling water treatment reactor 4 is provided with a grounding electrode 14. The grounding electrode 14 can be a stainless steel rod, a stainless steel plate or a stainless steel ring immersed in the organic wastewater 16.

[0048] The Fenton-like oxidation reactor 6 includes a water inlet spray head 18, a Fenton-like oxidation filler 19, and a porous catalyst carrier plate 20. Multiple groups of water inlet spray heads 18 are uniformly arranged in the upper part of the Fenton-like oxidation reactor 6, and multiple layers of Fenton-like oxidation fillers 19 are arranged below the multiple groups of water inlet spray heads 18. Each layer of Fenton-like oxidation filler 19 is uniformly placed on the porous catalyst carrier plate 20. The hole size of the porous catalyst carrier plate 20 is smaller than the diameter of the Fenton-like oxidation filler 19, and at the same time, the organic wastewater 16 can flow smoothly. After the organic wastewater flows through the second condenser 5, it enters the Fenton-like oxidation reactor 6 in the form of spraying. The wastewater contacts the Fenton in the Fenton-like oxidation filler 19 loaded on the upper porous catalyst carrier plate 20, and penetrates layer by layer to carry out the Fenton reaction, realizing the oxidation and degradation of organic matter in the wastewater, and finally converting into treated water that can be discharged.

[0049] A three-way valve 22 is arranged on the connecting pipeline between the second water pump 21 and the plasma bubbling water treatment reactor 4.

[0050] Figure 1The application discloses a heat pump temperature control type plasma cooperating Fenton oxidation grading organic wastewater treatment system. The organic wastewater 1 is driven by a first water pump 2 to flow through an evaporator 3, is cooled by low-temperature heat pump working medium to a temperature of 25 DEG C suitable for a plasma bubble oxidation reaction, and flows into a plasma bubble water treatment reactor 4. The gas 10 is driven by a gas pump 11 to enter a stainless steel aeration pipe 12 connected with a high-voltage power supply 13, is treated by the plasma bubble water treatment reactor 4, and the organic wastewater 16 is degraded to a certain organic pollutant, and a certain concentration of Fenton oxidation reaction raw material H2O2 is generated at the same time, and the pH of the organic wastewater 16 is reduced to about 2-3, which is more suitable for the Fenton oxidation reaction. Then the organic wastewater 16 flows through a first condenser 5, is heated by high-temperature heat pump working medium to 50 DEG C, flows into a Fenton-like oxidation reactor 6 to perform the Fenton oxidation reaction. The reacted organic wastewater can be driven by a circulating second water pump 21 to flow back to the plasma bubble water treatment reactor 4 to perform the circulating reaction. After the reaction is completed, the treated water flows out through a water outlet 23.

[0051] The high-voltage electrode in the plasma bubble water treatment reactor 4 is a stainless steel aeration pipe 12 immersed in the organic wastewater 16, and the stainless steel aeration pipe 12 and a grounding electrode 14 are driven by a high voltage of 7-20 kV, the gas 10 is excited into plasma in the stainless steel aeration pipe 12, and the plasma is converted into plasma bubbles 15 in the organic wastewater 16. The interface between the plasma bubbles 15 and the organic wastewater 16 generates oxidation substances such as ·OH, ·O2 - , O3 and H2O2 to perform the degradation reaction of the organic pollutants, and the pH of the organic wastewater 16 is reduced to the optimal pH 2-3 of the Fenton oxidation reaction, so that the consumption of the pH adjusting agent and the addition of H2O2 in the Fenton oxidation are reduced, and the economic efficiency of the Fenton oxidation reaction is improved.

[0052] The Fenton-like oxidation reactor 6 comprises a water inlet spray head 18, Fenton-like oxidation fillers 19, a porous catalyst carrier plate 20 and the water outlet 23. The water inlet spray head 18 is arranged in multiple groups according to the water distribution uniformity, the Fenton-like oxidation fillers 19 are uniformly placed on the porous catalyst carrier plate 20 and are arranged in multiple layers. The hole size of the porous catalyst carrier plate 20 is smaller than the diameter of the Fenton-like oxidation fillers 19, and the organic wastewater 16 can flow through the porous catalyst carrier plate 20 smoothly. The organic wastewater contacts the Fenton-like oxidation fillers 19 and penetrates layer by layer to perform the Fenton reaction, so that the organic substances in the wastewater are oxidized and degraded. The Fenton-like oxidation reactor 6 is communicated with the plasma bubble water treatment reactor 4 through the circulating second water pump 21 and a three-way valve 22, so that the plasma bubble water treatment and the Fenton-like oxidation circulation are realized, the organic wastewater is efficiently degraded, and the reaction conditions are optimized by adding reagents such as H2O2 and acid-base adjusting agents into the organic wastewater 16 through the three-way valve 22. The treated water is discharged from the system through the water outlet 23.

[0053] The load Fenton material 19 is Fe-N-C Fenton catalytic material synthesized by Enteromorpha prolifera and Fe(NO3)3·9H2O. The synthesis method of the Fe-N-C Fenton catalytic material is as follows: the Enteromorpha prolifera with a particle size of 160-250 μm is crushed and dried at 105°C for 24 h to remove water. The dried sample is pyrolyzed at 500°C under N2 flow (flow rate of 200 mL / min) at a rate of 5°C / min for 1 h, then KOH (the ratio of active biochar to KOH is 2:1) is added to increase the porosity. Then it is further pyrolyzed at 800°C under N2 flow (flow rate of 200 mL / min) at a rate of 5°C / min for 1 h, then washed with deionized water to neutral and the obtained powder is dried at 105°C for 24 h to obtain algal-based active biochar. The algal-based active biochar is mixed with Fe(NO3)3·9H2O and deionized water and stirred for 2 h, then placed in an 80°C oven to dry, and finally pyrolyzed at 500°C under N2 flow (flow rate of 200 mL / min) at a rate of 5°C / min for 3 h to obtain the final product Fe-N-C Fenton catalytic material.

[0054] The organic wastewater is methylene blue solution with a concentration of 100 mg / L and a volume of 250 mL.

[0055] The method for treating organic wastewater by using the heat pump temperature control type plasma and Fenton oxidation combined graded organic wastewater treatment system comprises the following steps:

[0056] Step S1, the organic wastewater 1 to be degraded is pumped into the plasma bubble water treatment reactor 4 through the first water pump 2 and the evaporator, the low-temperature working medium in the heat pump system evaporator 3 exchanges heat with the organic wastewater 1, so that the temperature of the organic wastewater is reduced to 25°C, which is suitable for the temperature of the plasma bubble oxidation reaction;

[0057] Step S2, the air 10 enters the stainless steel aeration pipe 12 through the air pump 11, the low-temperature plasma power supply 13 connected to the high-voltage electrode stainless steel aeration pipe 12 is adjusted to a discharge power of 70 W, under the driving of high voltage between the stainless steel aeration pipe 12 and the grounding electrode 15, the gas 10 is excited into plasma in the stainless steel aeration pipe 12 and bubbles into the organic wastewater 16 for degradation of organic pollutants;

[0058] Step S3, the treatment liquid 16 after low temperature plasma degradation flows out of the reactor under the driving of the liquid level pressure in the low temperature plasma reactor 4, and flows into the Fenton-like oxidation reactor 6 after passing through the second condenser 5. Meanwhile, the working medium at the outlet of the evaporator 3 is compressed by the compressor 7, and the temperature of the working medium is increased to 120℃ after work. In the second condenser 8, the high-temperature working medium transfers heat to the industrial or domestic water 24, and the temperature of the outlet water hot water 25 reaches 80℃. The working medium after being cooled heats the inlet water of the Fenton-like oxidation reactor 6 to 50℃ in the first condenser 5, so that the temperature of the organic wastewater 16 in the Fenton-like oxidation reactor 6 is the optimal Fenton reaction temperature.

[0059] Step S4, the wastewater flowing into the Fenton-like oxidation reactor 6 is first sprayed uniformly on the porous catalyst carrier plate 20 with the Fenton-like oxidation filler 19 uniformly placed thereon by the inlet water spray head 18, and penetrates layer by layer to realize the oxidation and degradation of organic matter in the wastewater.

[0060] Step S5, the treatment liquid after the Fenton-like oxidation reactor 6 degradation is discharged through the water outlet 23. Every 5 minutes, 3mL of sample is taken at the water outlet 23 to measure the pH, conductivity, COD and pollutant concentration of the organic wastewater 16. The pH meter is used to measure the pH value of the wastewater, the conductivity meter is used to measure the conductivity value of the wastewater, and the COD detector is used to measure the COD value of the wastewater. The pH meter is used to measure the pH value of the wastewater, the conductivity meter is used to measure the conductivity value of the wastewater, and the COD detector is used to measure the COD value of the wastewater. The absorbance of methylene blue solution is measured by a spectrophotometer, and the concentration of methylene blue in the solution is calculated by the standard relationship curve between the concentration of methylene blue solution and the absorbance. The standard curve relationship is as follows: 665nm Standard curve, the standard curve relationship is as follows:

[0061] c = 4.9186 OD 665nm mg / L

[0062] Step S6, the measurement results are compared with the national standard to determine whether the organic wastewater meets the discharge standard. If the standard is met, the treatment is completed. If the standard is not met, the wastewater in the Fenton-like oxidation reactor 6 is continuously circulated through the three-way valve 22 into the plasma bubbling water treatment reactor 4 by the second water pump 21, and H2O2, acid and alkali adjusting agents and other reagents are added to the organic wastewater 16 through the three-way valve 22 to optimize the reaction conditions. The treated water is discharged from the system through the water outlet 23.

[0063] Example 2

[0064] A method for treating organic wastewater by using a heat pump temperature-controlled plasma and Fenton oxidation combined organic wastewater treatment system, which is different from the embodiment 1 in that the temperature of the plasma bubble water treatment reactor 4 and the Fenton-like oxidation reactor 6 is maintained at 25℃ without temperature control by the heat pump system, and the method comprises the following steps:

[0065] Step S1, the organic wastewater 1 to be degraded is pumped into the plasma bubble water treatment reactor 4 through the first water pump 2 and the evaporator 3.

[0066] Step S2, the oxygen-containing gas 10 is pumped into the stainless steel aeration pipe 12 by the gas pump 11, the low-temperature plasma power supply 13 connected to the high-voltage electrode stainless steel aeration pipe 12 is adjusted to a discharge power of 70W, and the gas 10 is excited into plasma in the stainless steel aeration pipe 12 under the driving of the high voltage between the stainless steel aeration pipe 12 and the grounding electrode 15. The bubbles enter the organic wastewater 16 for degradation of organic pollutants.

[0067] Step S3, the treated liquid 16 after low-temperature plasma degradation flows out of the reactor under the driving of the liquid level pressure in the low-temperature plasma reactor 4, and flows into the Fenton-like oxidation reactor 6 after passing through the second condenser 5.

[0068] Step S4, the wastewater flowing into the Fenton-like oxidation reactor 6 is first uniformly sprayed on the porous catalyst carrier plate 20 with the Fenton-like oxidation filler 19 uniformly placed thereon by the water inlet spray head 18, and penetrates layer by layer for Fenton reaction to realize oxidation and degradation of organic matter in the wastewater.

[0069] Step S5, the treated liquid after degradation in the Fenton-like oxidation reactor 6 is discharged through the water outlet 23, and 3mL of sample is taken every 5min at the water outlet 23 to measure the pH, conductivity and COD of the organic wastewater 16. The pH value of the wastewater is measured by a pH meter, the conductivity value of the wastewater is measured by a conductivity meter, and the COD value of the wastewater is measured by a COD detector. The pH value of the wastewater is measured by a pH meter, the conductivity value of the wastewater is measured by a conductivity meter, and the COD value of the wastewater is measured by a COD detector. The absorbance of the methylene blue solution is measured by a spectrophotometer, and the concentration of the methylene blue in the solution is calculated by the standard relationship curve between the concentration and the absorbance of the methylene blue solution. The concentration c (mg / L) of the methylene blue solution and the absorbance OD 665nm of the standard curve are as follows:

[0070] c = 4.9186 OD 665nm mg / L

[0071] Step S6, the measurement results are compared with the national standard to determine whether the organic wastewater meets the discharge standard. If it meets the standard, the treatment is completed. If it does not meet the standard, the wastewater in the Fenton-like oxidation reactor 6 is continuously pumped through the three-way valve 22 into the plasma bubbling water treatment reactor 4 for recycling treatment by the second water pump 21. At the same time, reagents such as H2O2, acid and alkali adjusting agents can be added to the organic wastewater 16 through the three-way valve 22 to optimize the reaction conditions. The treated water is discharged from the system through the water outlet 23.

[0072] Example 3

[0073] The hot pump temperature control type plasma Fenton oxidation graded organic wastewater treatment system comprises the following steps:

[0074] A hot pump temperature control type plasma Fenton oxidation graded organic wastewater treatment system and method, the system structure and method are as described in Example 1, the difference is that the system does not control the temperature through the hot pump system, and does not use the Fenton-like oxidation reactor for organic wastewater degradation treatment.

[0075] Step S1, the organic wastewater to be degraded 1 is pumped into the plasma bubbling water treatment reactor 4 through the first water pump 2 and the evaporator 3;

[0076] Step S2, the oxygen-containing gas 10 is pumped into the stainless steel aeration pipe 12 through the gas pump 11, the low-temperature plasma power supply 13 connected to the high-voltage electrode stainless steel aeration pipe 12 is adjusted to a discharge power of 70W, and under the driving of the high voltage between the stainless steel aeration pipe 12 and the grounding electrode 15, the gas 10 is excited into plasma in the stainless steel aeration pipe 12. Bubble into the organic wastewater 16 for organic pollutant degradation;

[0077] Step S3, the organic wastewater 16 after degradation in the bubbling water treatment reactor 4 is sampled every 5 minutes for 3mL, and the pH, conductivity and COD of the organic wastewater 16 are measured. The pH value of the wastewater is measured by a pH meter, the conductivity value of the wastewater is measured by a conductivity meter, and the COD value of the wastewater is measured by a COD detector. The measurement results are compared with the national standard to determine whether the organic wastewater meets the discharge standard. If it meets the standard, the treatment is completed. The pH value of the wastewater is measured by a pH meter, the conductivity value of the wastewater is measured by a conductivity meter, and the COD value of the wastewater is measured by a COD detector. The concentration of methylene blue solution is calculated by the standard relationship curve of the concentration of methylene blue solution and the absorbance of methylene blue solution. The concentration c (mg / L) of methylene blue solution and the absorbance OD 665nm The standard curve is as follows:

[0078] c = 4.9186 OD 665nm mg / L

[0079] The devices of Example 1 and Example 2, Example 3 were used to treat organic wastewater according to the use method described in Example 1, Example 2 and Example 3, and the experimental results were repeated 3 times as shown in Figure 2 、 Figure 3 and Figure 4 , Figure 2 is a degradation rate graph of the heat pump temperature-controlled plasma Fenton oxidation staged organic wastewater of the present application, Figure 3 is a degradation pH graph of the heat pump temperature-controlled plasma Fenton oxidation staged organic wastewater of the present application, Figure 4 is a degradation energy efficiency graph of the heat pump temperature-controlled plasma Fenton oxidation staged organic wastewater of the present application when the degradation rate is 50%.

[0080] The organic wastewater is methylene blue solution with a concentration of 100 mg / L and a volume of 250 mL.

[0081] As can be seen from Figure 2 , the degradation rate of methylene blue reached 94% after 50 min of treatment by the device of Example 1. The degradation rate of methylene blue reached 81% after 50 min of treatment by the device of Example 2, while the degradation rate of methylene blue reached 60% after 50 min by the device of Example 3. The degradation rate of methylene blue reached 99% after 90 min of treatment by the device of Example 1. The degradation rate of methylene blue reached 90% after 90 min of treatment by the device of Example 2, while the degradation rate of methylene blue reached 83% after 90 min by the device of Example 3.

[0082] As can be seen from Figure 3 , the devices of Example 1, 2 and 3 can rapidly reduce the pH of the wastewater to meet the Fenton reaction conditions (pH 2-5) within 5 min after running, and gradually reduce and maintain the wastewater pH at about 2.8 with the reaction time.

[0083] As can be seen from Figure 4 , the degradation energy efficiency of the device of Example 1 was 603.6 mg / kWh when the degradation rate was 50%, which was 1.16 and 2.29 times that of Example 2 521.1 mg / kWh and Example 3 263.6 mg / kWh, respectively.

[0084] The application constructs a low-temperature plasma oxidation-Fenton oxidation staged reaction system for advanced oxidation of organic wastewater, and the evaporator 3 and the condenser of the heat pump system respectively absorb heat (cooling) and release heat (heating) of the water inlet of the plasma bubble water treatment reactor 4 and the Fenton oxidation reactor 6, so that the organic wastewater to be degraded meets the requirements of the plasma oxidation reaction optimum temperature 15-30 DEG C and the Fenton oxidation reaction optimum temperature 50-70 DEG C. At the same time, the heat pump system absorbs the waste heat of the wastewater through the evaporator 3 to heat the industrial or domestic water, and at the same time, the water inlet of the Fenton oxidation reactor 6 is heated, so that the plasma oxidation-Fenton oxidation staged reaction system can efficiently degrade the organic wastewater and efficiently utilize the heat energy.

[0085] It should be understood that although the present specification is described in terms of various embodiments, not every embodiment contains only one independent technical solution, and the description of the specification is only for the sake of clarity, and those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be combined appropriately to form other embodiments that those skilled in the art can understand.

[0086] The series of detailed descriptions listed above are only specific descriptions of the feasible embodiments of the application, and are not used to limit the protection scope of the application, and any equivalent embodiments or changes made without departing from the spirit of the application should be included in the protection scope of the application.

Claims

1. A heat pump temperature-controlled plasma synergistic Fenton oxidation staged organic wastewater treatment system, characterized in that, The device comprises a first water pump (2), a plasma bubble water treatment reactor (4), a Fenton-like oxidation reactor (6), a gas pump (11), a high-voltage power supply (13) and a heat pump temperature control device. The heat pump temperature control device comprises an evaporator (3), a first condenser (5), a compressor (7) and a second condenser (8). The first water pump (2) is connected to one end of the evaporator (3), and the other end of the evaporator (3) is connected to a first water inlet of the plasma bubble water treatment reactor (4). The water outlet of the plasma bubble water treatment reactor (4) is connected to one end of the first condenser (5), and the other end of the first condenser (5) is connected to a water inlet of the Fenton-like oxidation reactor (6). The Fenton-like oxidation reactor (6) is provided with a first water outlet in the middle and a second water outlet at the bottom. The second water outlet is connected to one end of a second water pump (21), and the other end of the second water pump (21) is connected to a second water inlet of the plasma bubble water treatment reactor (4). The working medium outlet of the evaporator (3) is connected to one end of the compressor (7) through a pipeline, the other end of the compressor (7) is connected to one end of the second condenser (8) through a pipeline, the other end of the second condenser (8) is connected to the working medium inlet of the first condenser (5) through a pipeline, and the working medium outlet of the first condenser (5) is connected to the working medium inlet of the evaporator (3) through a pipeline. The working medium inlet of the second condenser (8) is connected to a water inlet, and the working medium outlet of the second condenser (8) is connected to a water outlet. One end of the gas pump (11) is connected to a stainless steel aeration pipe (12) at the bottom of the plasma bubble water treatment reactor (4), and the stainless steel aeration pipe (12) is connected to the high-voltage power supply (13). The top of the plasma bubble water treatment reactor (4) is provided with an air outlet (17).

2. The heat pump temperature-controlled plasma synergic Fenton oxidation fractional organic wastewater treatment system according to claim 1, characterized in that, The organic wastewater (1) is driven by the first water pump (2) to flow through the evaporator (3) and is cooled to a preset temperature for plasma bubble oxidation reaction by the low-temperature heat pump working medium, and then flows into the plasma bubble water treatment reactor (4). The gas (10) is driven by the gas pump (11) to enter the stainless steel aeration pipe (12) connected to the high-voltage power supply (13), and after being treated by the plasma bubble water treatment reactor (4), the organic wastewater (16) is degraded while generating H2O2, the raw material for Fenton oxidation reaction, and the pH of the organic wastewater (16) is reduced. The organic wastewater (16) flows out of the water outlet of the plasma bubble water treatment reactor (4), flows through the first condenser (5) and is heated to a preset temperature by the high-temperature heat pump working medium, and then flows into the Fenton-like oxidation reactor (6) to perform Fenton oxidation reaction. The reacted organic wastewater is driven by the circulating second water pump (21) to flow back to the plasma bubble water treatment reactor (4) for circulating reaction. After the reaction is completed, the treated water flows out through the water outlet (23).

3. The heat pump temperature-controlled plasma synergic Fenton oxidation fractional organic wastewater treatment system according to claim 1, characterized in that, A stop valve (9) is arranged on the connecting pipeline between the working medium outlet of the first condenser (5) and the working medium inlet of the evaporator (3).

4. The heat pump temperature-controlled plasma synergic Fenton oxidation fractional organic wastewater treatment system according to claim 1, characterized in that, The plasma bubble water treatment reactor (4) is provided with a grounding electrode (14).

5. The heat pump temperature controlled plasma synergic Fenton oxidation staged organic wastewater treatment system according to claim 1, characterized in that, The Fenton-like oxidation reactor (6) comprises a water inlet spray head (18), Fenton-like oxidation filler (19), and a porous catalyst carrier plate (20); A plurality of water inlet spray heads (18) are uniformly arranged in the upper part of the Fenton-like oxidation reactor (6), and a plurality of layers of Fenton-like oxidation filler (19) are arranged below the plurality of water inlet spray heads (18), and each layer of Fenton-like oxidation filler (19) is uniformly placed on the porous catalyst carrier plate (20); the hole size of the porous catalyst carrier plate (20) is smaller than the diameter of the Fenton-like oxidation filler (19).

6. The heat pump temperature controlled plasma synergic Fenton oxidation staged organic wastewater treatment system according to claim 1, characterized in that, A three-way valve (22) is arranged on the connecting pipeline between the second water pump (21) and the plasma bubbling water treatment reactor (4).

7. A method for treating organic wastewater by using the heat pump temperature-controlled plasma and Fenton oxidation combined organic wastewater treatment system according to any one of claims 1-6, characterized in that, The method comprises the following steps: Step S1, the organic wastewater (1) to be degraded is pumped into the plasma bubbling water treatment reactor (4) through the first water pump (2) and the evaporator (3); Step S2, the oxygen-containing gas (10) enters the stainless steel aeration pipe (12) through the air pump (11), the plasma power supply (13) connected to the high-voltage electrode stainless steel aeration pipe (12) is adjusted to the discharge power, and under the driving of the high voltage between the stainless steel aeration pipe (12) and the grounding electrode (14), the gas (10) is excited into plasma in the stainless steel aeration pipe (12) and bubbles into the organic wastewater (16) to degrade the organic pollutants; Step S3, the treatment liquid after low-temperature plasma degradation flows out of the reactor under the driving of the liquid level pressure in the low-temperature plasma reactor (4) and flows into the Fenton-like oxidation reactor (6) after passing through the second condenser (5); Step S4, the treatment liquid flowing into the Fenton-like oxidation reactor (6) is first uniformly sprayed on the porous catalyst carrier plate (20) uniformly placed with the Fenton-like oxidation filler (19) through the water inlet spray head (18), and penetrates layer by layer to realize Fenton reaction and oxidize and degrade the organic matter in the wastewater; Step S5, the treatment liquid after degradation in the Fenton-like oxidation reactor (6) is discharged through the water outlet (23), and the pH, conductivity and COD of the treatment liquid are measured at the water outlet (23); Step S6, the measurement results are compared with the national standard to determine whether the treatment liquid meets the discharge standard, and if so, the treatment is completed; if not, the wastewater in the Fenton-like oxidation reactor (6) is continuously pumped into the plasma bubbling water treatment reactor (4) by the second water pump (21) for recycling treatment.

8. The method of treating organic wastewater by the heat pump temperature-controlled plasma synergistic Fenton oxidation staged organic wastewater treatment system according to claim 7, characterized in that, The organic wastewater (1) is driven by the first water pump (2) to flow through the evaporator (3) and is cooled by the low-temperature heat pump working medium to a temperature of 15-30℃ for plasma bubble oxidation reaction, and then flows into the plasma bubbling water treatment reactor (4). The gas (10) is driven by the air pump (11) into the stainless steel aeration pipe (12) connected to the high-voltage power supply (13), and after being treated by the plasma bubble water treatment reactor (4), the organic wastewater (16) is degraded while generating the Fenton oxidation reaction raw material H2O2, and the pH of the organic wastewater (16) is reduced to 2-3, which is more suitable for Fenton oxidation reaction; then the organic wastewater (16) flows through the first condenser (5) and is heated to 50-70℃ by the high-temperature heat pump working medium, and then flows into the Fenton-like oxidation reactor (6) for Fenton oxidation reaction.

9. The method of treating organic wastewater by the heat pump temperature-controlled plasma synergistic Fenton oxidation staged organic wastewater treatment system according to claim 8, characterized in that, The low-temperature working medium in the heat pump system evaporator (3) at-10-10℃ exchanges heat with the organic wastewater (1) at 30-80℃, so that the temperature of the organic wastewater is reduced to 15-30℃ suitable for plasma bubble oxidation reaction, and the working medium at the outlet of the evaporator (3) is compressed by the compressor (7) and then the temperature is increased to 80-140℃ after work, and in the second condenser (8), the high-temperature working medium transfers heat to industrial or domestic water (24), and the outlet water hot water (25) reaches a temperature of 80-100℃, and the working medium after cooling heats the water into the Fenton-like oxidation reactor (6) to 50-70℃ in the first condenser (5).

10. The method of treating organic wastewater by the heat pump temperature-controlled plasma synergistic Fenton oxidation staged organic wastewater treatment system according to claim 7, characterized in that, The Fenton-like oxidation filler (19) is a Fe-N-C Fenton catalytic material synthesized by Enteromorpha prolifera and Fe(NO3)3·9H2O; The synthesis method of the Fe-N-C Fenton catalytic material is as follows: the Enteromorpha prolifera with a particle size of 160-250μm is crushed and dried at 105℃ for 24h to remove water, obtaining a dried sample of activated biochar; the dried sample is pyrolyzed at 500℃ under the flow of N2 at a flow rate of 200mL / min at a rate of 5℃ / min for 1h, then KOH is added, and the ratio of activated biochar to KOH is 2:1; then pyrolysis is carried out at 800℃ under the flow of N2 at a flow rate of 200mL / min at a rate of 5℃ / min for 1h, then the obtained powder is washed with deionized water until neutral and dried at 105℃ for 24h to obtain an algal-based activated biochar; the algal-based activated biochar is mixed with Fe(NO3)3·9H2O and deionized water and stirred for 2h, then placed in an 80℃ oven for drying, and finally pyrolyzed at 500℃ under the flow of N2 at a flow rate of 200mL / min at a rate of 5℃ / min for 3h to obtain the final product Fe-N-C Fenton catalytic material.

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