High-oil lignite carbon wastewater efficient treatment process

Abstract

The present application relates to a kind of high oil high-efficiency processing technology of Lanthanum carbon wastewater, S100: Lanthanum carbon wastewater is extracted into first reaction tank, and suitable sulfuric acid is added to reaction tank and is stirred, so that the pH value in Lanthanum carbon wastewater is 3.5-4.5;S200: after stirring stops, polyaluminium chloride and polyacrylamide are added to reaction tank, after the suspended solids in Lanthanum carbon wastewater coagulation and precipitation, supernatant is extracted to second reaction tank;S300: in supernatant, compound demulsifier is added, and suitable polyacrylamide is added to carry out flocculation precipitation;S400: supernatant is extracted to third reaction tank, and iron-carbon micro-electrolysis is carried out in third reaction tank;S500: after the supernatant after iron-carbon micro-electrolysis is extracted to fourth reaction tank, after its pH value is modulated alkaline, it is treated by deamination;S600: after the supernatant after deamination treatment is extracted to fifth reaction tank, it is treated by photo-catalytic oxidation by semiconductor powder.

Description

Technical Field

[0001] This invention relates to a wastewater purification process, specifically a high-efficiency treatment process for high-oil semi-coke wastewater. Background Technology

[0002] Semi-coke wastewater mainly originates from coal pyrolysis, crude coal gas purification, and the refining processes of related coal chemical products. It is a mixed wastewater from different stages of the process. The wastewater contains high concentrations of oils, phenols, ammonia nitrogen, carbon dioxide, hydrogen sulfide, and some recalcitrant organic pollutants. All indicators exceed those of ordinary coking wastewater by more than 10 times, making it a type of industrial wastewater with low biodegradability and extremely difficult to treat. If the various high-concentration pollutants in semi-coke wastewater are not effectively treated, it will have a significant impact on both wastewater treatment processes and the natural environment. Currently, there is no mature technology specifically designed for the treatment of semi-coke wastewater.

[0003] Currently, the treatment of semi-coke wastewater in industry still follows the treatment processes used for coal gasification and coking wastewater. The main process includes pretreatment, secondary treatment, and tertiary treatment. The pretreatment process comprises two units: oil removal and dust removal, and phenol and ammonia recovery. The oil removal and dust removal unit mainly uses methods such as static separation, flotation, and centrifugation to separate heavy oil, light oil, and some coal slag from water. The phenol and ammonia recovery unit uses stripping, cooling flash evaporation, liquid-liquid extraction, and distillation to remove and recover acidic gases, ammonia, and phenols. Secondary treatment generally utilizes the oxidative decomposition of anaerobic and aerobic microorganisms to remove residual organic matter. Some industrial projects use incineration, but due to economic reasons, it cannot be widely adopted at present. Tertiary treatment mainly uses advanced oxidation and adsorption methods to treat some recalcitrant organic matter and color to meet emission standards.

[0004] The bottleneck problem in semi-coke wastewater treatment is oil removal. Currently, in industrial semi-coke wastewater treatment processes, both the oil removal and dust removal units and the biological treatment units can remove oil pollution. However, because high concentrations of oil pollutants have strong biological toxicity, they can cause the microorganisms in the biological treatment unit to lose their activity, thus affecting the wastewater treatment efficiency. Therefore, the removal of oil pollutants is mainly concentrated in the oil removal and dust removal unit. Due to the unsatisfactory removal effect, the oil residue in the wastewater will greatly affect subsequent treatment units. The large amount of oil residue will not only cause clogging of the phenol and ammonia recovery unit equipment and pipelines, making it difficult for the unit to operate continuously, but the toxic hydrocarbons in the oil can also poison or even kill the microorganisms in the biological treatment unit, causing the biological treatment unit to malfunction and affecting wastewater treatment. For the natural environment, the oil in the wastewater floats on the water surface and forms a dense film, which prevents oxygen from the air from freely entering and leaving the water, causing a decrease in dissolved oxygen in the water, leading to the death of some organisms due to hypoxia, and also affecting the photosynthesis of aquatic plants, disrupting the ecological balance. Based on practical industrial experience, the oil content of the wastewater entering the phenol-ammonia wastewater treatment unit needs to be minimized. Otherwise, oily substances will adhere to the trays and heat exchanger pipes, causing a decrease in equipment processing efficiency and consequently affecting the phenol-ammonia removal efficiency. Furthermore, due to the continuous accumulation of oil in the pipes, the maintenance cycle of the phenol-ammonia unit is significantly shortened, making long-term stable operation impossible. Simultaneously, the oil content in the effluent from the phenol-ammonia unit will also increase accordingly, increasing the treatment load on the biological treatment unit, affecting microbial activity, and posing significant challenges to wastewater treatment.

[0005] The effectiveness of oil removal is mainly related to the degree of removal of emulsified oil from the wastewater. The oil in semi-coke wastewater is mainly insoluble tar that is washed out during cooling. Based on the different forms in which insoluble tar exists in water, it can be divided into floating oil, dispersed oil, emulsified oil, and dissolved oil.

[0006] (1) Floating oil: This is the most common form of oil in semi-coke wastewater. It generally floats or aggregates on the water surface in a continuous phase state, forming a stable oil film or oil layer. The oil droplets in floating oil are relatively large, generally greater than 100 μm, accounting for 70% to 95% of the oil content in the wastewater. It can be separated from the wastewater by simple physical methods.

[0007] (2) Dispersed oil: refers to oils suspended in the aqueous phase, usually dispersed in the aqueous phase as tiny oil droplets with a droplet size between 10 and 100 μm. The state of dispersed oil is easily affected by conditions such as temperature, flow state, and mixing intensity, so the droplet size varies greatly. If there is an electric charge on the surface of the oil droplet or it is subjected to mechanical force, the dispersed oil is relatively stable; otherwise, it is unstable and can be separated by standing for a long time. Therefore, dispersed oil is relatively easy to remove from water.

[0008] (3) Emulsified oil: Due to the presence of surfactants, oils exist in water in an emulsified state. Surfactants can turn oil droplets into charged nuclei, and due to the influence of surface energy and polarity, the charged oil droplet nuclei can adsorb oppositely charged ions or polar water molecules in the water, forming an interfacial film between the oil and water phases, preventing oil droplets from colliding and agglomerating, and dispersing them more stably in the water. Emulsified oil droplets have a particle size of less than 10 μm, generally between 100 and 2000 nm, making them difficult to remove using traditional oil removal methods.

[0009] (4) Dissolved oil: refers to oils that exist in water in a molecular state. The oil droplets are generally only a few nanometers in size, and the oil and water form a homogeneous system, which is extremely stable and very difficult to remove. However, because the solubility of oil droplets in water is very small, the content in water is generally less than 0.5%.

[0010] The floating oil and dispersed oil in semi-coke wastewater are not stable in water and can be removed by simple physical sedimentation or decantation. However, emulsified oil is difficult to remove using traditional methods due to its small particle size and the presence of an oil-water interface film. This is the main reason why the oil concentration in semi-coke wastewater remains high after passing through the deoiling and dust removal unit.

[0011] Current pretreatment oil removal processes mainly include gravity sedimentation, centrifugal separation, chemical demulsification sedimentation, and electrochemical flocculation. However, these methods have some serious drawbacks. For example, gravity sedimentation and centrifugal separation cannot remove emulsified oil, electrochemical flocculation easily causes secondary pollution, air flotation cannot effectively separate and recover light and heavy oil, and filter materials are easily clogged and contaminated. Faced with this situation, it is necessary to find an efficient and simple oil-water separation method to treat semi-coke wastewater. Summary of the Invention

[0012] The main objective of this invention is to provide a high-efficiency treatment process for high-oil semi-coke wastewater, achieving efficient oil removal while having minimal impact on subsequent treatment processes.

[0013] To achieve the above objectives, the present invention provides a high-efficiency treatment process for high-oil semi-coke wastewater, comprising the following steps:

[0014] S100: Acidification destabilizes the system – add acid:

[0015] The semi-coke wastewater is drawn into the first reaction tank, and a suitable amount of sulfuric acid is added to the reaction tank and stirred to make the pH value of the semi-coke wastewater 3.5-4.5.

[0016] S200: Acidity Adjustment and Stabilization – Coagulation:

[0017] After stirring stops, add polyaluminum chloride and polyacrylamide to the reaction tank. After the suspended solids in the semi-coke wastewater coagulate and settle, the supernatant is pumped into the second reaction tank.

[0018] S300: Demulsification and oil removal:

[0019] Add a compound demulsifier to the supernatant and add an appropriate amount of polyacrylamide to induce floc precipitation;

[0020] S400: Iron-Carbon Micro-Electrolysis

[0021] The supernatant from step S300 is extracted into the third reaction vessel, where the iron-carbon micro-electrolysis reaction is carried out.

[0022] S500: Ammonia stripping:

[0023] The supernatant after iron-carbon micro-electrolysis is drawn into the fourth reaction tank, and its pH value is adjusted to alkaline before deammoniation treatment is carried out.

[0024] S600: Photocatalytic oxidation

[0025] The supernatant after deammoniation treatment in step S500 is extracted into the fifth reaction vessel and subjected to photocatalytic oxidation treatment with semiconductor powder.

[0026] Preferably, it includes the following steps:

[0027] S100: Acidification destabilizes the system – add acid:

[0028] The semi-coke wastewater is drawn into the first reaction tank, and an appropriate amount of sulfuric acid is added to the reaction tank and stirred for 2-3 minutes to make the pH value of the semi-coke wastewater 3.5-4.5.

[0029] S200: Acidity Adjustment and Stabilization – Coagulation:

[0030] After stirring stops, add 100 ppm of polyaluminum chloride and polyacrylamide to the reaction tank. After the suspended solids in the semi-coke wastewater coagulate and settle, the supernatant is pumped into the second reaction tank.

[0031] S300: Demulsification and oil removal:

[0032] Add 1000 ppm of compound demulsifier to the supernatant and add appropriate polyacrylamide to precipitate flocs;

[0033] S400: Iron-Carbon Micro-Electrolysis

[0034] The supernatant from step S300 is extracted into the third reaction vessel, where the iron-carbon micro-electrolysis reaction is carried out.

[0035] S500: Ammonia stripping:

[0036] The supernatant after iron-carbon micro-electrolysis is drawn into the fourth reaction tank, and its pH value is adjusted to 8.5-9.5 before deammoniation treatment is carried out.

[0037] S600: Photocatalytic oxidation

[0038] The supernatant after deammoniation treatment in step S500 is extracted into the fifth reaction vessel and subjected to photocatalytic oxidation treatment with semiconductor powder.

[0039] Preferably, the fifth reaction vessel includes a vessel body, an aeration pipe disposed inside the vessel body, and a powder adding device disposed above the vessel body, the powder adding device being connected to the aeration pipe.

[0040] More preferably, the aeration pipe includes an aeration main pipe, and the powder addition device is disposed on the aeration main pipe.

[0041] More preferably, the powder adding device includes a first straight pipe section, a conical pipe section, and a second straight pipe section arranged coaxially. The first straight pipe section is fixedly connected to the small-diameter end of the conical pipe section, one end of the second straight pipe section is fixedly connected to the large-diameter end of the conical pipe section, and the other end of the second straight pipe section is inserted into the aeration main pipe. The first straight pipe section is located at the top, and an air inlet is provided on one side of the first straight pipe section. The air inlet is located in the tangential direction of the first straight pipe section, and the semiconductor powder is blown into the first straight pipe section through the air inlet.

[0042] In a further preferred embodiment, the first straight pipe section is equipped with an escape prevention pipe, which is coaxially arranged with the first straight pipe section.

[0043] More preferably, the escape tube is a tapered tube, with its small-diameter end fixedly connected to the first straight pipe section, and the small-diameter end of the escape tube communicating with the outside, while the large-diameter end of the escape tube is not inserted into the tapered pipe section.

[0044] In a further preferred embodiment, the first straight pipe section is also coaxially provided with a jet pipe, one end of which is connected to the compressor, and the other end of which is inserted into the second straight pipe section.

[0045] More preferably, the gas ejected from the jet pipe can enter the aeration main pipe, and the semiconductor powder can flow in the aeration pipe with the gas ejected from the jet pipe, and then escape out of the aeration pipe with the gas, thereby entering the supernatant.

[0046] The beneficial effects of this invention are as follows:

[0047] (1) The acid-adjusting coupled chemical compound demulsifier method used in this invention has a more efficient oil removal effect and a lower cost compared with the existing demulsification method for semi-coke wastewater. From the stabilization mechanism of emulsified oil, it can be known that oil droplets become charged due to the ionization and adsorption of surfactants, resulting in a double-layer structure similar to the Stern model at the oil-water interface, preventing collisions and aggregation between oil droplets. When the pH value in the system decreases, H… + The number of H began to increase. +Due to the repulsive effect between charges, the oil enters the adsorption layer on the surface of the oil droplet, which leads to the destruction of the double electric layer structure. The oil droplet becomes neutral and aggregates with each other to form a larger oil droplet, which increases the probability of contact between the demulsifier and the oil droplet, and greatly improves the oil removal efficiency.

[0048] (2) This invention applies micro-electrolysis technology to the treatment of semi-coke wastewater, and moves the acid adjustment step in the micro-electrolysis process to the pretreatment process. This step is coupled with a demulsifier to first perform efficient oil removal. After oil removal is completed, the acid adjustment step in the micro-electrolysis process is eliminated. At the same time, photocatalytic oxidation technology is coupled to improve the wastewater treatment effect, reduce operating costs, improve the stability of the wastewater treatment process, and enable the effluent to meet the discharge standards.

[0049] (3) The present invention also provides a powder addition device. By combining the device with the aeration pipe, semiconductor powder can be added to the semi-coke wastewater, thereby avoiding the agglomeration phenomenon caused by directly adding semiconductor powder to the semi-coke wastewater. Thus, the powder addition device replaces the stirring device. The device has a simple structure, low manufacturing cost, and effectively saves production costs. Attached Figure Description

[0050] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0051] Figure 1 This is a process flow diagram of the present invention;

[0052] Figure 2 This is a schematic diagram of the structure of the third reaction vessel of the present invention;

[0053] Figure 3 This is a schematic diagram of the powder addition device of the present invention.

[0054] Explanation of reference numerals in the attached figures

[0055] 10. Third reaction tank; 20. Aeration device;

[0056] 30. Powder adding device; 31. Air inlet; 32. First straight pipe section;

[0057] 33. Tapered pipe section; 34. Second straight pipe section; 35. Escape prevention pipe; 36. Jet nozzle. Detailed Implementation

[0058] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Those skilled in the art can make similar extensions without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0059] like Figure 1 As shown in the figure, this embodiment provides a high-efficiency treatment process for high-oil semi-coke wastewater, including the following steps:

[0060] S100: Acid Adjustment and Stabilization - Adding Acid: Draw the semi-coke wastewater into the first reaction tank, add appropriate sulfuric acid to the reaction tank and stir for 2-3 minutes to make the pH value of the semi-coke wastewater 3.5-4.5;

[0061] S200: Acid Adjustment and Stabilization - Coagulation: After stirring stops, add 100ppm of polyaluminum chloride and polyacrylamide to the reaction tank. After the suspended solids in the semi-coke wastewater coagulate and settle, the supernatant is pumped to the second reaction tank.

[0062] S300: Demulsification and oil removal: Add 1000ppm of compound demulsifier to the supernatant and add appropriate polyacrylamide to precipitate flocs;

[0063] In this embodiment, steps S100-S300 are the acid adjustment and destabilization stage and the demulsification and oil removal stage of this application. From the stabilization mechanism of emulsified oil, it is known that oil droplets become charged due to the ionization and adsorption of surfactants, resulting in a double-layer structure at the oil-water interface similar to the Stern model, preventing collisions and aggregation between oil droplets. When the pH value in the system decreases, H... + The number of H began to increase. + Because the repulsive effect between charges enters the adsorption layer on the surface of the oil droplets, the double electric layer structure is destroyed, the oil droplets become neutral and aggregate to form larger oil droplets, which increases the probability of contact between the demulsifier and the oil droplets, and greatly improves the oil removal efficiency. Therefore, in this embodiment, the pH value is reduced to between 3.5 and 4.5 to facilitate the subsequent process.

[0064] S400: Iron-carbon micro-electrolysis: The supernatant from step S300 is drawn into the third reaction vessel, where the iron-carbon micro-electrolysis reaction is carried out.

[0065] This step is the iron-carbon micro-electrolysis stage. As mentioned above, the wastewater after oil removal is still in an acidic state. Integrating iron-carbon micro-electrolysis technology has two advantages: 1. Iron-carbon micro-electrolysis is optimally performed at around pH 4. Simultaneously, the pH of the wastewater will rise to neutral or weakly alkaline after electrolysis (this is because during the reaction, iron, acting as the anode, is oxidized to form Fe). 2+ and Fe 3+Plasma, while producing hydroxide precipitates, these precipitates can adsorb and co-precipitate pollutants. In addition, the generated hydrogen ions will cause the pH value of the wastewater to decrease. However, as the micro-electrolysis reaction proceeds, the acidic substances in the wastewater are gradually consumed, and the pH value will gradually rise. At the same time, some alkaline substances, such as iron hydroxide, will be produced during the iron corrosion process, which will also cause the pH value to rise. Therefore, after the wastewater is treated by micro-electrolysis, the pH value will usually rise to the neutral or weakly alkaline range. As a connecting process between the oil removal and deammoniation links, it can reduce the amount of alkali added to adjust the pH of the denitrification unit; 2. Iron-carbon micro-electrolysis technology has strong advantages for recalcitrant industrial wastewater: (1) reducing the COD of wastewater; (2) breaking the chain and improving the biodegradability of wastewater; (3) reducing the toxicity of wastewater; (4) removing the color of wastewater.

[0066] The principle of iron-carbon micro-electrolysis: Iron-carbon micro-electrolysis is based on the galvanic cell reaction in electrochemistry. When iron and carbon are immersed in an electrolyte solution, due to the 1.2V electrode potential difference between Fe and C, countless micro-battery systems are formed, creating an electric field in their space. The nascent ferrous ions generated by the anodic reaction have strong reducing power, which can reduce certain organic matter and open the double bonds of certain unsaturated groups (such as carboxyl groups -COOH and azo groups -N=N-), decomposing some recalcitrant cyclic and long-chain organic compounds into easily biodegradable small-molecule organic compounds, thus improving biodegradability. In addition, ferrous and trivalent ions are good flocculants, especially the newly generated ferrous ions, which have higher adsorption-flocculation activity. Adjusting the pH of wastewater can cause iron ions to become flocculent precipitates of hydroxides, adsorbing suspended or colloidal microparticles and organic polymers in wastewater, further reducing the color of wastewater, and removing some organic pollutants to purify the wastewater. The cathodic reaction produces a large amount of nascent [H] and [O]. Under slightly acidic conditions, these active components can undergo redox reactions with many components in the wastewater, causing the organic macromolecules to undergo chain-breaking degradation, thereby eliminating the color of the organic wastewater and improving its biodegradability.

[0067] S500: Ammonia Removal: The supernatant after iron-carbon micro-electrolysis is drawn into the fourth reaction tank, and its pH value is adjusted to 8.5-9.5 before ammonia removal treatment. Preferably, the pH value is adjusted to 8.5-9.5 before ammonia removal treatment. After micro-electrolysis, the COD and toxicity of the semi-coke wastewater are significantly reduced. After ammonia removal, i.e., the ammonia stripping system, the ammonia nitrogen in the wastewater is reduced from 3000-5000 mg / L to less than 200 mg / L.

[0068] S600: Photocatalytic oxidation: The supernatant after deammoniation treatment in step S500 is extracted into the fifth reaction vessel and photocatalytically oxidized using semiconductor powder.

[0069] In this step, photocatalytic oxidation technology allows photocatalytic materials (photosensitizers, etc.) to generate several powerful oxidizing groups under ultraviolet or visible light: hydroxyl radicals (•OH), ozone (O2), and free radicals (•OH). 3 ), superoxide radicals (•O) 2 It can also non-selectively degrade pollutants in wastewater through oxidation-reduction reactions.

[0070] In this step, the photocatalytic oxidation material is prepared as a powder (i.e., semiconductor powder) and added to the supernatant to accelerate the oxidation reaction. However, agglomeration is prone to occur during the addition of the semiconductor powder to the supernatant; that is, the semiconductor powder clumps together in the supernatant instead of dispersing. Therefore, a stirring device is needed to break up the powder during addition, but agglomeration still occurs during stirring. Additionally, to increase the reaction rate, an aeration device 20 is typically added in this step.

[0071] In this embodiment, the powder adding device 30 and the aeration device 20 are effectively combined. The aeration device 20 blows the semiconductor powder into the supernatant, which makes the powder enter the supernatant more evenly. At the same time, the stirring device is not required.

[0072] Specifically, in this embodiment, such as Figure 2 and Figure 3 As shown, the fifth reaction vessel includes a vessel body, an aeration pipe disposed inside the vessel body, and a powder adding device 30 disposed above the vessel body. The powder adding device 30 is connected to the aeration pipe. The aeration pipe includes a main aeration pipe, and the powder adding device 30 is disposed on the main aeration pipe.

[0073] Specifically, the powder adding device 30 includes a first straight pipe section 32, a conical pipe section 33, and a second straight pipe section 34 arranged coaxially. The first straight pipe section 32 is fixedly connected to the small-diameter end of the conical pipe section 33, and one end of the second straight pipe section 34 is fixedly connected to the large-diameter end of the conical pipe section 33. The other end of the second straight pipe section 34 is inserted into the aeration main pipe. The first straight pipe section 32 is located at the top, and an air inlet 31 is provided on one side of the first straight pipe section 32. The air inlet 31 is located in the tangential direction of the first straight pipe section 32, and the semiconductor powder is blown into the first straight pipe section through the air inlet 31. After the semiconductor powder is blown into the first straight pipe section 32, it enters the tapered pipe section 33. The tapered pipe section 33 slows down the semiconductor powder to prevent it from falling too quickly into the second straight pipe section 34. The semiconductor powder entering the second straight pipe section 34 enters the aeration main pipe of the aeration device 20. It flows with the gas sprayed into the aeration main pipe and finally escapes through the aeration holes in the aeration device 20, thus entering the supernatant.

[0074] In this embodiment, the first straight pipe section 32 is also coaxially provided with a jet pipe 36. One end of the jet pipe 36 is connected to the compressor, and the other end of the jet pipe 36 is inserted into the second straight pipe section 34. In this way, the jet pipe 36 can be directly connected to the aeration device 20, and the jet pipe 36 can aspirate the semiconductor powder falling onto the aeration main pipe directly opposite the second straight pipe section 34. In addition, to prevent backflow from the jet pipe 36 and disruption of the airflow between the conical pipe section 33 and the first straight pipe section 32, an escape tube 35 is provided in the first straight pipe section 32. The escape tube 35 is coaxially arranged with the first straight pipe section 32, allowing the backflowing airflow to escape out of the first straight pipe section 32. Simultaneously, to prevent semiconductor powder from escaping with the backflowing airflow, the escape tube 35 is inserted into the first pipe. The escape tube 35 is a conical tube, with its small-diameter end fixedly connected to the first straight pipe section 32 and open to the outside. The large-diameter end of the escape tube 35 is not inserted into the conical pipe section 33. The conical shape of the escape tube 35 increases the rotational resistance of the airflow within the first straight pipe section 32, thereby reducing the air velocity. This further reduces the air velocity of the semiconductor powder within the conical tube and prevents the semiconductor powder from escaping.

[0075] In addition, since this application adds a jet pipe 36, the jet pipe 36 can replace the compressor of the aeration device 20, so that air can be blown directly into the aeration device 20 through the jet pipe 36. This allows the sprayed gas to enter the aeration main pipe, and the semiconductor powder can flow in the aeration device 20 with the gas sprayed from the jet pipe, and escape out of the aeration device 20 with the gas, thereby entering the supernatant.

[0076] The treatment results using the above process are shown in the table below:

[0077]

[0078] Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

Claims

1. A high-oil lignite coal wastewater efficient treatment process, characterized in that, The method comprises the following steps: S100: acid adjusting and stability breaking - adding acid: The semi-coke wastewater is pumped into a first reaction tank, and appropriate sulfuric acid is added into the reaction tank and stirred for 2-3 minutes, so that the pH value of the semi-coke wastewater is 3.5-4.5; S200: acid adjusting and stability breaking - coagulation: After the stirring is stopped, 100 ppm of polyaluminum chloride and polyacrylamide are added into the reaction tank, and after the suspended solids in the semi-coke wastewater are coagulated and precipitated, the supernatant is pumped into a second reaction tank; S300: demulsification and oil removal: 1000 ppm of a compounded demulsifier is added into the supernatant, and appropriate polyacrylamide is added for flocculent precipitation; S400: iron-carbon micro-electrolysis: The supernatant in step S300 is pumped into a third reaction tank, and an iron-carbon micro-electrolysis reaction is carried out in the third reaction tank; S500: ammonia evaporation: The supernatant after the iron-carbon micro-electrolysis is pumped into a fourth reaction tank, and after the pH value is adjusted to be alkaline, ammonia removal treatment is carried out; S600: photocatalytic oxidation: The supernatant after the ammonia removal treatment in step S500 is pumped into a fifth reaction tank, and photocatalytic oxidation treatment is carried out by using a semiconductor powder.

2. The efficient treatment process of high-oil lignite coal wastewater according to claim 1, characterized in that, The method comprises the following steps: S100: acid adjusting and stability breaking - adding acid: The semi-coke wastewater is pumped into a first reaction tank, and appropriate sulfuric acid is added into the reaction tank and stirred for 2-3 minutes, so that the pH value of the semi-coke wastewater is 3.5-4.5; S200: acid adjusting and stability breaking - coagulation: After the stirring is stopped, 100 ppm of polyaluminum chloride and polyacrylamide are added into the reaction tank, and after the suspended solids in the semi-coke wastewater are coagulated and precipitated, the supernatant is pumped into a second reaction tank; S300: demulsification and oil removal: 1000 ppm of a compounded demulsifier is added into the supernatant, and appropriate polyacrylamide is added for flocculent precipitation; S400: iron-carbon micro-electrolysis: The supernatant in step S300 is pumped into a third reaction tank, and an iron-carbon micro-electrolysis reaction is carried out in the third reaction tank; S500: ammonia evaporation: The supernatant after the iron-carbon micro-electrolysis is pumped into a fourth reaction tank, and after the pH value is adjusted to be alkaline, ammonia removal treatment is carried out; S600: photocatalytic oxidation: The supernatant after the ammonia removal treatment in step S500 is pumped into a fifth reaction tank, and photocatalytic oxidation treatment is carried out by using a semiconductor powder.

3. The efficient treatment process of high-oil lignite coal wastewater according to claim 1 or 2, characterized in that, The fifth reaction tank comprises a tank body, an aeration pipe arranged in the tank body, and a powder adding device arranged above the tank body, and the powder adding device is in communication with the aeration pipe.

4. The efficient treatment process of high-oil lignite coal wastewater according to claim 3, characterized in that, The aeration pipe comprises an aeration main pipe, and the powder adding device is arranged on the aeration main pipe.

5. The efficient treatment process of high-oil lignite coal wastewater according to claim 4, characterized in that, The powder adding device comprises a first straight pipe section, a taper pipe section and a second straight pipe section arranged coaxially, one end of the second straight pipe section is fixedly connected with a large-diameter end of the taper pipe section, the other end of the second straight pipe section is inserted into the aeration main pipe, the first straight pipe section is located at the uppermost position, one side of the first straight pipe section is provided with an air inlet, the air inlet is located in a tangent direction of the first straight pipe section, and the semiconductor powder is blown into the first straight pipe section through the air inlet.

6. The efficient treatment process of high oil gas waste water according to claim 5, characterized in that, The first straight pipe section is provided with an anti-escape pipe which is arranged coaxially with the first straight pipe section.

7. The efficient treatment process of high oil gas waste water according to claim 6, characterized in that, The anti-escape pipe is a tapered pipe, a small-diameter end of the anti-escape pipe is fixedly connected with the first straight pipe section, and the small-diameter end of the anti-escape pipe is in communication with the outside, and a large-diameter end of the anti-escape pipe is not inserted into the tapered pipe section.

8. The efficient treatment process of high-oil lignite coal wastewater according to claim 7, characterized in that, The first straight pipe section is coaxially provided with a jet pipe, one end of the jet pipe is in communication with a compressor, and the other end of the jet pipe is inserted into the second straight pipe section.

9. The efficient treatment process of high oil gas waste water according to claim 8, characterized in that, The gas jetted out of the jet pipe can enter the aeration main pipe, the semiconductor powder can flow in the aeration pipe along with the gas jetted out of the jet pipe, and is diffused out of the aeration pipe along with the gas, so as to enter supernatant.

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