Heat pump temperature control type plasma synergistic Fenton oxidation grading organic wastewater treatment system and method

Abstract

The invention discloses a heat pump temperature control type plasma synergistic Fenton oxidation grading organic wastewater treatment system and method. The system comprises a first water pump, a plasma bubbling water treatment reactor, a Fenton-like oxidation reactor, an air 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, low-temperature plasma heat energy and low-potential active oxide H2O2 are efficiently utilized to perform oxidative degradation on organic matters in a water body after plasma advanced oxidation reaction, and accurate temperature control in each stage of wastewater oxidation is realized so as to be beneficial to reaching the optimal temperature; due to the addition of a Fenton-like oxidation filler on the porous catalyst supporter plate, ferrous iron Fe < 2 + > in particles and H2O2 are subjected to a Fenton oxidation reaction to generate ferric iron Fe < 3 + > and. OH with strong oxidizing property to participate in organic matter degradation, and meanwhile, sensible heat in wastewater, electric heat provided by plasmas and chemical reaction heat in the plasma oxidation process are utilized through temperature control; the efficient degradation of industrial organic wastewater is favorably realized.

Description

Technical Field

[0001] The present invention relates to the technical field of organic wastewater treatment, and in particular to a heat pump temperature-controlled plasma coordinated Fenton oxidation graded organic wastewater treatment system and method. Background Art

[0002] Industrial organic wastewater is widely produced in the printing and dyeing, chemical, papermaking, and pharmaceutical industries. The organic pollutants contained in them are resistant to photolysis, oxidation, and biodegradation. It is urgent to develop suitable advanced oxidation technologies for organic wastewater. Low-temperature plasma advanced oxidation is an emerging green and environmentally friendly water treatment technology with the advantages of non-selective degradation of organic matter, renewable green electricity drive, and continuous deep treatment. It has great development potential in the industrial wastewater treatment market containing difficult-to-degrade organic matter. Low-temperature plasma advanced oxidation technology mainly generates plasma by exciting gas with high voltage. The high-energy electrons in the plasma discharge at the liquid interface to generate oxidative active particles (·OH, ·O2 - , O3, H2O2) participate in the degradation of organic pollutants in water. However, the energy efficiency of organic pollutant degradation in low-temperature plasma water treatment systems still needs to be improved.

[0003] Combining low-temperature plasma technology with Fenton oxidation technology to construct a composite advanced oxidation technology will help improve the energy efficiency of low-temperature plasma organic wastewater degradation. In the process of treating organic wastewater, plasma will produce a certain concentration of H2O2 as a raw material for Fenton oxidation reaction while degrading organic pollutants. At the same time, the pH of organic wastewater is reduced to about 2-3, which is suitable for Fenton oxidation reaction. However, the suitable reaction temperature of low-temperature plasma bubbling reaction is different from that of Fenton oxidation reaction. At present, it is difficult to control the temperature of low-temperature plasma coupled Fenton oxidation integrated system. In addition, the discharge temperature of industrial organic wastewater is usually high. For example, the wastewater temperature in printing and dyeing wastewater is 40-90℃, the outlet temperature of papermaking wastewater can reach 40-60℃, and the temperature of petrochemical wastewater can reach 60℃, which are not suitable temperatures for plasma bubble oxidation reaction. Summary of the invention

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

[0005] The technical solution of the present invention is:

[0006] A heat pump temperature-controlled plasma-coordinated Fenton oxidation graded organic wastewater treatment system comprises a first water pump, a plasma bubbling water treatment reactor, a Fenton-like oxidation reactor, an air pump, a high-voltage power supply and a heat pump temperature control device; the heat pump temperature control device comprises an evaporator, a first condenser, a compressor and a second condenser;

[0007] The first water pump is connected to one end of the evaporator, and the other end of the evaporator is connected to the first water inlet of the plasma bubbling water treatment reactor; the water outlet of the plasma bubbling water treatment reactor is connected to one end of the first condenser, and the other end of the first condenser is connected to the water inlet of the Fenton-like oxidation reactor; the Fenton-like oxidation reactor 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 the second water pump, and the other end of the second water pump is connected to the second water inlet of the plasma bubbling water treatment reactor;

[0008] The working fluid outlet of the evaporator is connected to one end of the compressor through a pipeline, the other end of the compressor is connected to one end of the second condenser through a pipeline, the other end of the second condenser is connected to the working fluid inlet of the first condenser through a pipeline, the working fluid outlet of the first condenser is connected to the working fluid inlet of the evaporator through a pipeline; the working fluid inlet of the second condenser is connected to the treated water inlet, and the working fluid outlet of the second condenser is connected to the treated water outlet;

[0009] One end of the air pump is connected to a stainless steel aeration pipe at the bottom of a plasma bubbling water treatment reactor, and the stainless steel aeration pipe is connected to a high-voltage power supply; an air outlet is arranged at the top of the plasma bubbling water treatment reactor.

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

[0011] The gas is driven by an air pump into a stainless steel aeration pipe connected to a high-voltage power supply. After being treated in a plasma bubbling water treatment reactor, the organic wastewater produces H2O2, a raw material for a Fenton oxidation reaction, while degrading organic pollutants. At the same time, the pH of the organic wastewater is reduced. The organic wastewater flows from the outlet of the plasma bubbling water treatment reactor through a first condenser and is heated to a preset temperature by a high-temperature heat pump working fluid, and then flows into a Fenton-like oxidation reactor for a Fenton oxidation reaction. The organic wastewater after the reaction is driven by a circulating second water pump to flow back to the plasma bubbling water treatment reactor for a circulating reaction. After the reaction is completed, the treated water flows out through the outlet.

[0012] In the above solution, a stop valve is provided on the connecting pipe between the working medium outlet of the first condenser and the working medium inlet of the evaporator.

[0013] In the above scheme, a grounding electrode is provided in the plasma bubbling water treatment reactor.

[0014] In the above scheme, the Fenton-like oxidation reactor comprises a water inlet sprinkler, a Fenton-like oxidation filler, and a porous catalyst support plate;

[0015] A plurality of groups of water inlet spray heads are evenly arranged at the upper part of the Fenton-like oxidation reactor, and a plurality of layers of Fenton-like oxidation fillers are arranged below the plurality of groups of water inlet spray heads. Each layer of Fenton-like oxidation fillers is evenly placed on a porous catalyst support plate. The pore size of the porous catalyst support plate is smaller than the diameter of the Fenton-like oxidation filler.

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

[0017] A method for treating organic wastewater according to the heat pump temperature-controlled plasma coordinated Fenton oxidation graded organic wastewater treatment system comprises the following steps:

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

[0019] Step S2, oxygen-containing gas enters the stainless steel aeration tube through an air pump, and the plasma power supply connected to the high-voltage electrode stainless steel aeration tube is adjusted to the discharge power. Under the high voltage drive between the stainless steel aeration tube and the ground electrode, the gas is excited into plasma in the stainless steel aeration tube and bubbles into the organic wastewater to degrade organic pollutants;

[0020] Step S3, the treated liquid after low-temperature plasma degradation flows out of the reactor driven by the liquid level pressure in the low-temperature plasma reactor, and 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 evenly sprayed on the porous catalyst support plate on which the Fenton-like oxidation filler is evenly placed through the water inlet spray head, and penetrates layer by layer to perform Fenton reaction, thereby achieving oxidative degradation of organic matter in the wastewater;

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

[0023] Step S6, comparing the measurement results with the national standards to determine whether the treated liquid meets the discharge standards. If it does, the treatment is completed; if it does not, the wastewater in the Fenton-like oxidation reactor is continued to enter the plasma bubbling water treatment reactor through the second water pump for circulation treatment.

[0024] In the above scheme, the organic wastewater is driven by the first water pump to flow through the evaporator and is cooled by the low-temperature heat pump working fluid to the temperature of the plasma bubble oxidation reaction of 15 to 30° C., and flows into the plasma bubbling water treatment reactor;

[0025] The gas is driven by an air pump into a stainless steel aeration pipe connected to a high-voltage power supply. After being treated in a plasma bubbling water treatment reactor, the organic wastewater produces H2O2, a raw material for the Fenton oxidation reaction, while degrading organic pollutants. At the same time, the pH of the organic wastewater is reduced to 2-3, which is more suitable for the Fenton oxidation reaction. The organic wastewater then flows through the first condenser and is heated to 50-70°C by the high-temperature heat pump working fluid and flows into a Fenton-like oxidation reactor for a Fenton oxidation reaction.

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

[0027] In the above scheme, the Fenton-like oxidation filler is a Fe-NC Fenton catalytic material obtained by synthesizing Enteromorpha striata and Fe(NO3)3·9H2O;

[0028] The synthesis method of the Fe-NC Fenton catalytic material is as follows: crushing Enteromorpha with a particle size of 160 to 250 μm and drying it at 105° C. for 24 hours to remove moisture, thereby obtaining a dry sample of activated biochar; pyrolyzing the dry sample at 500° C. at a rate of 5° C. / min for 1 hour under a N2 flow with a gas flow rate of 200 mL / min, and then adding KOH, wherein the mass ratio of activated biochar to KOH is 2:1, to increase the porosity; and then further pyrolyzing the dried sample at 800° C. at a N2 flow with a gas flow rate of 200 mL / min at a rate of 5° C. / min. The algae-based activated biochar was mixed with Fe(NO3)3·9H2O and deionized water in a mass ratio of 100:1:600 ​​and stirred for 2 h, then placed in an oven at 80°C for drying, and finally pyrolyzed at 500°C and a N2 flow with a gas flow rate of 200 mL / min at a rate of 5°C / min for 3 h to obtain the final product, Fe-NC Fenton catalytic material.

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

[0030] The present invention can be used in a heat pump temperature-controlled plasma coordinated Fenton oxidation graded organic wastewater treatment system. By coupling the Fenton reaction and realizing temperature control, the low-temperature plasma heat energy and low-potential active oxide H2O2 can be efficiently used to oxidize and degrade organic matter in water after the plasma advanced oxidation reaction, and accurate temperature control can be achieved at each stage of wastewater oxidation to facilitate reaching the optimal temperature. The addition of the Fenton oxidation filler on the porous catalyst support plate makes the divalent iron Fe in the particles 2+ Fenton oxidation reaction with H2O2 generates trivalent iron Fe 3+ and the strongly oxidizing ·OH participate in the degradation of organic matter. At the same time, the introduction of temperature control makes use of the sensible heat in the wastewater, the electric heat provided by the plasma, and the chemical reaction heat in the plasma oxidation process, which is conducive to the optimal oxidation temperature in each stage to achieve efficient degradation of industrial organic wastewater.

[0031] The heat pump temperature-controlled plasma-coordinated Fenton oxidation graded organic wastewater treatment system and method provided by the present invention can effectively improve the energy efficiency of low-temperature plasma advanced oxidation and the efficiency of organic wastewater degradation, and provide an effective technical solution for energy-saving transformation and optimization of low-temperature plasma organic wastewater treatment systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a schematic diagram of the heat pump temperature-controlled plasma coordinated Fenton oxidation graded organic wastewater treatment system of the present invention;

[0033] Figure 2 This is a graph of organic wastewater degradation rate by heat pump temperature-controlled plasma synergistic with Fenton oxidation classification of the present invention;

[0034] Figure 3 This is the pH diagram of the heat pump temperature-controlled plasma synergistic Fenton oxidation graded organic wastewater degradation of the present invention;

[0035] Figure 4 It is a degradation energy efficiency diagram of the heat pump temperature-controlled plasma synergistic with Fenton oxidation classification of organic wastewater when the degradation rate is 50%;

[0036] The markings in the figure are as follows: 1—organic wastewater; 2—first water pump; 3—evaporator; 4—plasma bubbling water treatment reactor; 5—second condenser; 6—Fenton-type 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—ground electrode; 15—low-temperature plasma bubbles; 16—organic wastewater after plasma degradation; 17—gas outlet; 18—sprinkler; 19—Fenton-type oxidation filler; 20—porous catalyst carrier plate; 21—second water pump; 22—three-way valve; 23—water outlet; 24—industrial and domestic water; 25—outlet hot water. DETAILED DESCRIPTION

[0037] The embodiments of the present invention are described in detail below.

[0038] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0039] Example 1

[0040] A heat pump temperature-controlled plasma-assisted Fenton oxidation graded organic wastewater treatment system comprises 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 to one end of the evaporator 3, and the other end of the evaporator 3 is connected to the first water inlet of the plasma bubbling water treatment reactor 4; the water outlet of the plasma bubbling 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 the 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 the second water pump 21, and the other end of the second water pump 21 is connected to the second water inlet of the plasma bubbling water treatment reactor 4;

[0042] The working fluid 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 fluid inlet of the first condenser 5 through a pipeline, and the working fluid outlet of the first condenser 5 is connected to the working fluid inlet of the evaporator 3 through a pipeline; the working fluid inlet of the second condenser 8 is connected to the treated water inlet, and the working fluid outlet of the second condenser 8 is connected to the treated water outlet;

[0043] One end of the air pump 11 is connected to 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 to a high voltage power supply 13 ; an air outlet 17 is provided 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 by the low-temperature heat pump working medium to a preset temperature for the plasma bubble oxidation reaction, and then flows into the plasma bubbling water treatment reactor 4;

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

[0046] A stop valve 9 is provided on the connecting pipe 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 support plate 20; multiple groups of water inlet spray heads 18 are evenly arranged at 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, and each layer of Fenton-like oxidation fillers 19 is evenly placed on the porous catalyst support plate 20; the pore size of the porous catalyst support 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 flowing through the second condenser 5, the organic wastewater enters the Fenton-like oxidation reactor 6 in the form of spraying, and the wastewater contacts the Fenton in the Fenton-like oxidation filler 19 loaded on the upper porous catalyst support plate 20, and penetrates layer by layer to perform Fenton reaction, so as to realize the oxidation and degradation of organic matter in the wastewater, and finally convert it into treated water that is allowed to be discharged.

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

[0050] Figure 1The schematic diagram of the heat pump temperature-controlled plasma coordinated Fenton oxidation graded organic wastewater treatment system of the present invention is shown in the figure. 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 fluid to a temperature of 25°C suitable for the plasma bubble oxidation reaction and flows into the plasma bubbling water treatment reactor 4. The gas 10 is driven by the air pump 11 to enter the stainless steel aeration pipe 12 connected to the high-voltage power supply 13. After being treated by the plasma bubbling water treatment reactor 4, the organic wastewater 16 produces a certain concentration of Fenton oxidation reaction raw material H2O2 while degrading certain organic pollutants. At the same time, the pH of the organic wastewater 16 is reduced to about 2 to 3, which is more suitable for the Fenton oxidation reaction. Then the organic wastewater 16 flows through the first condenser 5 and is heated to 50°C by the high-temperature heat pump working fluid and flows into the Fenton-like oxidation reactor 6 for Fenton oxidation reaction. The organic wastewater after the reaction can be driven by the circulating second water pump 21 to flow back to the plasma bubbling water treatment reactor 4 for a circulating reaction. After the reaction is completed, the treated water flows out through the outlet 23.

[0051] The high voltage electrode in the plasma bubbling water treatment reactor 4 is a stainless steel aeration tube 12 immersed in the organic wastewater 16 and driven by a high voltage of 7 to 20 kV between the ground electrode 14. The gas 10 is excited into plasma in the stainless steel aeration tube 12 and aerated into plasma bubbles 15 in the organic wastewater 16. The plasma bubbles 15 generate ·OH and ·O2 at the interface with the organic wastewater 16. - , O3, H2O2 and other oxides to degrade organic pollutants, and at the same time reduce the pH of organic wastewater 16 to the optimal pH 2-3 for Fenton oxidation reaction, which can reduce the consumption of Fenton oxidation pH adjustment drugs and H2O2 addition, and improve the economy of Fenton oxidation reaction.

[0052] The Fenton-like oxidation reactor 6 includes a water inlet spray head 18, a Fenton-like oxidation filler 19, a porous catalyst support plate 20 and a water outlet 23. The water inlet spray head 18 is arranged in multiple groups according to the uniformity of water distribution, and the Fenton-like oxidation filler 19 is evenly placed on the porous catalyst support plate 20 and arranged in multiple layers. The pore size of the porous catalyst support 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. The organic wastewater contacts the Fenton-like oxidation filler 19 and penetrates layer by layer to perform the Fenton reaction, thereby realizing the oxidation and degradation of organic matter in the wastewater. The Fenton-like oxidation reactor 6 is connected to the plasma bubbling water treatment reactor 4 through the circulating second water pump 21 and the three-way valve 22, so that the plasma bubbling water treatment and the Fenton-like oxidation cycle can be realized, and the organic wastewater can be efficiently degraded. At the same time, H2O2, acid-base regulators and other reagents 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 outlet 23.

[0053] The supported Fenton material 19 is a Fe-NC Fenton catalytic material synthesized from Enteromorpha and Fe(NO3)3·9H2O. The synthesis method of the Fe-NC Fenton catalytic material is as follows: Enteromorpha with a particle size of 160 to 250 μm is crushed and dried at 105°C for 24 hours to remove moisture. The dried sample is pyrolyzed at a rate of 5°C / min for 1 hour at 500°C under N2 flow (flow rate of 200 mL / min), and KOH (the ratio of activated biochar to KOH is 2:1) is added to increase the porosity. Subsequently, it is further pyrolyzed at a rate of 5°C / min for 1 hour at 800°C under N2 flow (flow rate of 200 mL / min), and then washed with deionized water to neutrality and the resulting powder is dried at 105°C for 24 hours to obtain algae-based activated biochar. The algae-based activated biochar was mixed with Fe(NO3)3·9H2O and deionized water and stirred for 2 h, then dried in an oven at 80 °C, and finally pyrolyzed at 500 °C for 3 h at a rate of 5 °C / min under a N2 flow (flow rate of 200 mL / min) to obtain the final product, Fe-NC Fenton catalytic material.

[0054] The organic wastewater is a 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-controlled plasma coordinated with the Fenton oxidation graded organic wastewater treatment system comprises the following steps:

[0056] Step S1, pumping the organic wastewater 1 to be degraded into the plasma bubbling water treatment reactor 4 through the first water pump 2 and the evaporator, the -10°C low-temperature working fluid in the heat pump system evaporator 3 performs heat exchange with the organic wastewater 1, so that the temperature of the organic wastewater drops to 25°C, a temperature suitable for plasma bubble oxidation reaction;

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

[0058] Step S3, the treated liquid 16 after low-temperature plasma degradation flows out of the reactor driven by 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. At the same time, the temperature of the working medium at the outlet of the evaporator 3 rises to 120° C. after being compressed by the compressor 7 and doing 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 hot water 25 reaches 80° C. The cooled working medium heats the inlet water of the Fenton-like oxidation reactor 6 to 50° C. 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 evenly sprayed on the porous catalyst support plate 20 on which the Fenton-like oxidation fillers 19 are evenly placed through the water inlet spray head 18, and penetrates layer by layer to perform the Fenton reaction, thereby achieving oxidative degradation of organic matter in the wastewater;

[0060] Step S5, the treated liquid after degradation by the Fenton-like oxidation reactor 6 is discharged through the water outlet 23, and 3 mL is sampled every 5 minutes at the water outlet 23 to measure the pH, conductivity, COD and pollutant concentration 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 meter. 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 meter. The absorbance of the 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 the methylene blue solution and the absorbance. Methylene blue solution concentration c (mg / L) and absorbance OD 665nm The standard curve relationship is as follows:

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

[0062] Step S6, the measurement result is 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 continues to flow through the three-way valve 22 through the second water pump 21 into the plasma bubbling water treatment reactor 4 for cyclic treatment. At the same time, H2O2, acid-base regulators and other reagents 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 outlet 23.

[0063] Example 2

[0064] A method for treating organic wastewater by heat pump temperature-controlled plasma coordinated with Fenton oxidation graded organic wastewater treatment system. The difference between this embodiment and embodiment 1 is that the temperature is not controlled by the heat pump system, and the temperature of the plasma bubbling water treatment reactor 4 and the Fenton-like oxidation reactor 6 is maintained at 25°C. The method comprises the following steps:

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

[0066] Step S2, oxygen-containing gas 10 enters stainless steel aeration tube 12 through air pump 11, and low-temperature plasma power supply 13 connected to high-voltage electrode stainless steel aeration tube 12 is adjusted to discharge power 70W. Driven by high voltage between stainless steel aeration tube 12 and ground electrode 15, gas 10 is excited into plasma in stainless steel aeration tube 12 and bubbles into 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 driven by 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 evenly sprayed on the porous catalyst support plate 20 on which the Fenton-like oxidation fillers 19 are evenly placed through the water inlet spray head 18, and penetrates layer by layer to perform Fenton reaction, thereby achieving oxidative degradation of organic matter in the wastewater.

[0069] Step S5, the treated liquid after degradation by the Fenton-like oxidation reactor 6 is discharged through the water outlet 23, and 3 mL is sampled every 5 minutes 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 meter. 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 meter. The absorbance of the 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 the methylene blue solution and the absorbance. Methylene blue solution concentration c (mg / L) and absorbance OD 665nm The standard curve relationship is as follows:

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

[0071] Step S6, the measurement result is 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 continues to flow through the three-way valve 22 through the second water pump 21 into the plasma bubbling water treatment reactor 4 for cyclic treatment. At the same time, reagents such as H2O2 and acid-base regulators 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 outlet 23.

[0072] Example 3

[0073] The claimed heat pump temperature-controlled plasma synergistic Fenton oxidation graded organic wastewater treatment system comprises the following steps:

[0074] A heat pump temperature-controlled plasma-assisted Fenton oxidation graded organic wastewater treatment system and method, the system structure and method are as described in Example 1, except that the system does not control the temperature through a heat pump system, nor does it use a Fenton-like oxidation reactor to degrade organic wastewater.

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

[0076] Step S2, oxygen-containing gas 10 enters stainless steel aeration tube 12 through air pump 11, and low-temperature plasma power supply 13 connected to high-voltage electrode stainless steel aeration tube 12 is adjusted to discharge power 70W. Driven by high voltage between stainless steel aeration tube 12 and ground electrode 15, gas 10 is excited into plasma in stainless steel aeration tube 12 and bubbled into organic wastewater 16 for degradation of organic pollutants;

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

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

[0079] The devices of Examples 1, 2 and 3 were used to treat organic wastewater according to the methods described in Examples 1, 2 and 3. The experimental results were repeated 3 times. Figure 2 , Figure 3 and Figure 4 As shown, Figure 2 This is a graph of organic wastewater degradation rate of the heat pump temperature-controlled plasma synergistic with Fenton oxidation classification of the present invention, Figure 3 This is the pH diagram of the heat pump temperature-controlled plasma synergistic Fenton oxidation graded organic wastewater degradation of the present invention, Figure 4 This is a degradation energy efficiency diagram of the heat pump temperature-controlled plasma synergistic with Fenton oxidation classification of organic wastewater when the degradation rate is 50%.

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

[0081] Depend on Figure 2 It can be seen that after 50 minutes of treatment with the device of Example 1, the degradation rate of methylene blue reached 94%. After 50 minutes of treatment with the device of Example 2, the degradation rate of methylene blue reached 81%, while the degradation rate of methylene blue reached 60% at 50 minutes with the device of Example 3. After 90 minutes of treatment with the device of Example 1, the degradation rate of methylene blue reached 99%. After 90 minutes of treatment with the device of Example 2, the degradation rate of methylene blue reached 90%, while the degradation rate of methylene blue reached 83% at 90 minutes with the device of Example 3.

[0082] Depend on Figure 3 It can be seen that the devices of Examples 1, 2, and 3 can quickly reduce the pH of the wastewater to a pH (2 to 5) that meets the Fenton reaction conditions within 5 minutes after operation, and the pH value of the wastewater gradually decreases and is maintained at about 2.8 as the reaction time increases.

[0083] Depend on Figure 4 It can be seen that the degradation energy efficiency of the device in Example 1 is 603.6 mg / kWh when the degradation rate is 50%, which is 1.16 and 2.29 times that of Example 2521.1 mg / kWh and Example 3263.6 mg / kWh respectively.

[0084] The present invention constructs a low-temperature plasma oxidation-Fenton oxidation hierarchical reaction system for advanced oxidation of organic wastewater, and at the same time, the evaporator 3 and the condenser of the heat pump system absorb heat (cool) and release heat (heat) for the inlet water of the plasma bubbling water treatment reactor 4 and the Fenton-like oxidation reactor 6, respectively, so that the organic wastewater to be degraded meets the requirements of the optimal temperature of 15 to 30° C. for the plasma oxidation reaction and the optimal temperature of 50 to 70° C. for the Fenton oxidation reaction. At the same time, the heat pump system absorbs the waste heat of the wastewater through the evaporator 3 to heat industrial or domestic water, and at the same time heats the inlet water of the Fenton-like oxidation reactor 6, so as to achieve efficient degradation of organic wastewater and efficient utilization of heat energy in the plasma oxidation-Fenton oxidation hierarchical reaction system.

[0085] It should be understood that although this specification is described according to various embodiments, not every embodiment contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

[0086] The series of detailed descriptions listed above are only specific descriptions of feasible embodiments of the present invention. They are not intended to limit the scope of protection of the present invention. All equivalent embodiments or changes that do not deviate from the technical spirit of the present invention should be included in the scope of protection of the present invention.

Claims

1. A heat pump temperature-controlled plasma synergistic Fenton oxidation graded organic wastewater treatment system, characterized in that: It comprises 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); 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 the first water inlet of the plasma bubbling water treatment reactor (4); the water outlet of the plasma bubbling 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 the 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 the second water pump (21), and the other end of the second water pump (21) is connected to the second water inlet of the plasma bubbling water treatment reactor (4); The working fluid 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 fluid inlet of the first condenser (5) through a pipeline, and the working fluid outlet of the first condenser (5) is connected to the working fluid inlet of the evaporator (3) through a pipeline; The working medium inlet of the second condenser (8) is connected to the treated water inlet, and the working medium outlet of the second condenser (8) is connected to the treated water outlet; One end of the air pump (11) is connected to 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 to a high-voltage power supply (13); an air outlet (17) is provided at the top of the plasma bubbling water treatment reactor (4).

2. The heat pump temperature-controlled plasma synergistic Fenton oxidation graded organic wastewater treatment system according to claim 1 is characterized in that: The organic wastewater (1) is driven by a first water pump (2) to flow through an evaporator (3), is cooled by a low-temperature heat pump working fluid to a preset temperature for a plasma bubble oxidation reaction, and flows into a plasma bubbling water treatment reactor (4); The gas (10) is driven by an air pump (11) to enter a stainless steel aeration pipe (12) connected to a high-voltage power supply (13). After being treated by a plasma bubbling water treatment reactor (4), the organic wastewater (16) produces Fenton oxidation reaction raw material H2O2 while degrading organic pollutants. At the same time, the pH value of the organic wastewater (16) is reduced. The organic wastewater (16) flows from the water outlet of the plasma bubbling water treatment reactor (4) through a first condenser (5) and is heated to a preset temperature by a high-temperature heat pump working medium. The organic wastewater (16) flows into a Fenton-like oxidation reactor (6) for Fenton oxidation reaction. After the reaction, the organic wastewater is driven by a circulating second water pump (21) to flow back to the plasma bubbling water treatment reactor (4) for a circulating reaction. After the reaction is completed, the treated water flows out through a water outlet (23).

3. The heat pump temperature-controlled plasma synergistic Fenton oxidation graded organic wastewater treatment system according to claim 1 is characterized in that: A stop valve (9) is provided on the connecting pipe 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 synergistic Fenton oxidation graded organic wastewater treatment system according to claim 1 is characterized in that: A grounding electrode (14) is provided in the plasma bubbling water treatment reactor (4).

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

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

7. A method for treating organic wastewater using the heat pump temperature-controlled plasma assisted Fenton oxidation graded organic wastewater treatment system according to any one of claims 1 to 6, characterized in that: The following steps are involved: Step S1, pumping the organic wastewater to be degraded (1) into a plasma bubbling water treatment reactor (4) through a first water pump (2) and an evaporator (3); Step S2, the oxygen-containing gas (10) enters the stainless steel aeration pipe (12) through the air pump (11), and the plasma power supply (13) connected to the high-voltage electrode stainless steel aeration pipe (12) is adjusted to a discharge power. Under the high voltage drive between the stainless steel aeration pipe (12) and the ground 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 organic pollutants; Step S3, the treated liquid after low-temperature plasma degradation flows out of the reactor driven by 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 treated liquid flowing into the Fenton-like oxidation reactor (6) is first evenly sprayed on the porous catalyst support plate (20) on which the Fenton-like oxidation filler (19) is evenly placed through the water inlet spray head (18), and penetrates layer by layer to perform Fenton reaction, thereby achieving oxidative degradation of organic matter in the wastewater; Step S5, the treated 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 treated liquid are measured at the water outlet (23); Step S6, comparing the measurement result with the national standard to determine whether the treated liquid 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 fed into the plasma bubbling water treatment reactor (4) through the second water pump (21) for circulation treatment.

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

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

10. The method for treating organic wastewater by heat pump temperature-controlled plasma coordinated with Fenton oxidation graded organic wastewater treatment system according to claim 7, characterized in that: The Fenton-like oxidation filler (19) is a Fe-NC Fenton catalytic material obtained by synthesizing Enteromorpha striata and Fe(NO3)3·9H2O; The synthesis method of the Fe-NC Fenton catalytic material is as follows: crushing Enteromorpha with a particle size of 160 to 250 μm and drying it at 105° C. for 24 hours to remove moisture, thereby obtaining a dry sample of activated biochar; pyrolyzing the dry sample at 500° C. for 1 hour under a N2 flow with a gas flow rate of 200 mL / min at a rate of 5° C. / min, and then adding KOH, wherein the ratio of activated biochar to KOH is 2:1; and then pyrolyzing the dried sample at 800° C. under a N2 flow with a gas flow rate of 200 mL / min at a rate of 5° C. / min. The algae-based activated biochar was pyrolyzed at a rate of 5°C / min for 1 h under a N2 flow, then washed with deionized water until neutral and the resulting powder was dried at 105°C for 24 h to obtain algae-based activated biochar; the algae-based activated biochar was mixed with Fe(NO3)3·9H2O and deionized water and stirred for 2 h and then placed in an oven at 80°C for drying, and finally pyrolyzed at 500°C for 3 h under a N2 flow with a gas flow rate of 200 mL / min to obtain the final product, Fe-NC Fenton catalytic material.

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