A method for resource utilization of semi-coke wastewater

Abstract

The present application relates to a kind of resource utilization methods of semi-coke wastewater, including oil separation precipitation, phenol removal by filter pressing, resin oil removal and phenol removal, electrolytic oxidation, evaporation concentration, spray drying and recrystallization purification ammonium sulfate step, by adding sulfuric acid, ammonia water to semi-coke wastewater pH control, further by scientific experimental method reduces COD, BOD in wastewater, improve the original semi-coke wastewater treatment technology oil removal and phenol removal process to cause the problem such as phenol recovery difficulty and by-product ammonium sulfate impurity, by adding sulfuric acid in advance, adjust pH to lower level, so that most phenols are precipitated and recovered, and then further recover oil and phenols using resin;Sulfuric acid and ammonia water control pH at the same time, respectively recover ammonia and phenolic substances in wastewater, obtain phenolic products and by-product ammonium sulfate products, realize resource recovery, produce good economic benefits, while the steam water is treated by biochemical-MBR, realize water reuse.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of semi-coke wastewater treatment, and relates to a method for recycling and utilizing semi-coke wastewater, in particular to a method and system for recycling and comprehensively treating semi-coke wastewater. BACKGROUND

[0002] Semi-coke, also known as semi-carbon, is a new type of carbon material prepared by low-temperature dry distillation of high-quality fine coal. It has the characteristics of high fixed carbon, high chemical activity, high specific resistance, and low content of impurities such as ash, sulfur, phosphorus, and water. Therefore, it gradually replaces coke in the production of calcium carbide and ferroalloy.

[0003] Semi-coke wastewater, also known as semi-coke wastewater, is an industrial wastewater formed during the low-temperature dry distillation (about 600-800℃) of low-rank coal (non-caking coal, weakly caking coal, long flame coal) and the coal gas purification process. This wastewater is complex in composition and contains a large amount of difficult-to-degrade and highly toxic pollutants, such as benzene series, phenols, polycyclic aromatic hydrocarbons, nitrogen-oxygen heterocyclic compounds, and inorganic pollutants such as sulfides, cyanides, and thiocyanates. It is a typical high-pollution and high-toxicity industrial wastewater.

[0004] The phenols and petroleum substances contained in semi-coke wastewater are organic substances with high toxicity and poor degradability. Long-term accumulation in the environment can cause serious harm to human health and ecological balance. Current common technologies for treating semi-coke wastewater in China include steam stripping, electro-Fenton technology, and wet oxidation technology. These commonly used semi-coke wastewater treatment technologies have the following problems: (1) the removal rate of tar substances in semi-coke wastewater is low, leading to high load in subsequent process treatment and easy collapse; (2) the organic substances contained in the wastewater are highly toxic and have high content, making it difficult for biochemical processes to operate stably; (3) the treatment depth of semi-coke wastewater is not sufficient, and the recycling rate of ammonia and phenolic substances in the wastewater is low, which needs to be further improved. SUMMARY

[0005] Therefore, in order to solve the above problems in the process of treating semi-coke wastewater, the present application provides a method for recycling and utilizing semi-coke wastewater, which fully recycles and utilizes ammonia and phenols in semi-coke wastewater through reasonable physicochemical treatment, obtains phenolic tar and by-product ammonium sulfate, and uses biochemical-MBR process in the subsequent process to make the steam out water meet the discharge standard, realizing the purification and recycling of the steam out water and improving the recycling rate of the wastewater.

[0006] To achieve the above purpose, the present application provides the following technical solutions:

[0007] A method for recycling and utilizing semi-coke wastewater, comprising the following steps:

[0008] S1. Oil-water separation and sedimentation: The raw wastewater from semi-coke is pumped into the oil-water separation and sedimentation tank, and a demulsifier is added to initially achieve oil-water separation. The lower layer of wastewater is then taken into the next treatment process.

[0009] S2, Filtration treatment: The oil-removed wastewater obtained in step S1 is placed in a flocculation sedimentation tank, and sulfuric acid is added to adjust the pH of the wastewater to 6-8. If necessary, a wastewater treatment flocculant, such as PAC, is added and stirred thoroughly to obtain flocculent solids. Then, solid-liquid separation is carried out in a filter press to obtain flocculated wastewater.

[0010] S3. Phenol removal by pressure filtration: Add sulfuric acid to the wastewater obtained in step S2 to adjust the pH of the wastewater to 0-1.5. After standing, use a filter press to further remove phenolic substances from the wastewater in advance, so that the subsequent equipment can work better.

[0011] S4. Resin oil and phenol removal: The wastewater obtained in step S3 is passed sequentially through columns of oil removal resin and phenol removal resin to further remove oil and phenol substances from the wastewater and finally obtain relatively clear wastewater.

[0012] S5. Electrolytic oxidation: Ammonia water is added to the wastewater obtained in step S4 to adjust the pH value of the wastewater to 2-3. Then, electrolytic oxidation is carried out under the condition of current range of 3-8A. After standing and separating, the organic matter in the wastewater is further removed. At the same time, the organic matter in the wastewater is oxidized and activated to increase the BOD / COD value of the subsequent distilled water, which facilitates the biochemical treatment of the distilled water.

[0013] S6. Evaporation and Concentration: Add ammonia to the wastewater obtained in step S5 to adjust the pH value of the wastewater to 4-5, and then enter the evaporator for evaporation and concentration to obtain ammonium sulfate concentrate. The condensate after condensing the distillate is subjected to biochemical treatment to meet the industrial water standards for reuse. The ammonium sulfate concentrate enters the concentrate transfer tank.

[0014] S7. Spray Drying - Rotary Kiln: The ammonium sulfate concentrate obtained in step S6 is pumped into a spray drying tower. Hot air at 200-400℃ is used to evaporate the water, and the exhaust gas is discharged into the VOC treatment system. The resulting solid enters a rotary kiln, where hot air at 250-300℃ is used to heat-treat the ammonium sulfate solid in the rotary kiln, making the organic matter adhering to the surface of the ammonium sulfate solid insoluble in water. This step yields crude ammonium sulfate.

[0015] S8. Dissolving-Filtration: Add the crude ammonium sulfate obtained in step S7 to a dissolving and stirring tank, and then use a filter press to remove organic and inorganic substances that are insoluble in water, so as to obtain an ammonium sulfate solution with low impurity content.

[0016] S9. Evaporation and Crystallization-Drying: The ammonium sulfate solution obtained in step S8 is evaporated, centrifuged, and dried to obtain by-product ammonium sulfate;

[0017] S10, Biochemical-MBR Treatment: The distillate obtained from steps S9 and S6 is subjected to biochemical treatment and testing, and then recycled after meeting the standards.

[0018] Furthermore, in step S1, the raw wastewater from semi-coke is allowed to stand for 24 hours before slag removal is performed to promote the full aggregation of solid impurities in the wastewater.

[0019] Furthermore, in step S3, sulfuric acid is added to adjust the pH to 0-1.5, thereby removing phenols from the wastewater at low cost.

[0020] Furthermore, in step S4, the wastewater is cleaned before being treated with oil-removing resin and phenol-removing resin. During the resin cleaning process, steam and organic solvents (such as methanol, ethanol, etc.) are sequentially introduced into the resin column to remove the organic matter adsorbed on the resin, resulting in a mixture containing oil, phenol and organic matter, which is then recycled as tar.

[0021] Furthermore, in step S5, the electrolysis oxidation time is 2-4 minutes, the current is adjusted to 4-7 A, and the pH is adjusted to 2-3. Under these parameters, the activity of the electrolysis reaction is improved, which helps to enhance the efficiency of electrolysis oxidation, and the BOD / COD of the subsequently evaporated water is increased to above 0.3.

[0022] Furthermore, in step S6, an evaporator, such as a multi-effect evaporator or an MVR evaporator, is used to evaporate and concentrate the aforementioned wastewater until the ammonium sulfate concentration reaches 20-40%. Before the wastewater enters the evaporator, the pH of the feed liquid is controlled at 4-5 to reduce ammonia gas escape.

[0023] Furthermore, in step S7, spray drying-rotary kiln is used to evaporate the water in the concentrate obtained in step S6 using hot air at 200-400℃ to obtain crude ammonium sulfate solid. The crude ammonium sulfate solid is then kept at 200-300℃ in a rotary kiln for 1-3 hours.

[0024] Furthermore, steps S8 and S9 employ a dissolution-evaporation-crystallization-drying process to finally obtain the byproduct ammonium sulfate.

[0025] Furthermore, the phenolic substances collected in step S3 and the mixture of oil-phenol and organic matter collected in step S4 are recycled into phenolic tar. After steps S1-S9, phenols and ammonium sulfate in the semi-coke wastewater are separated to obtain by-products phenolic tar and by-product ammonium sulfate, respectively.

[0026] Furthermore, in step S10, a biochemical-MBR system is used to treat the distillate water to remove ammonia nitrogen and organic matter, enabling the distillate water to be reused.

[0027] The beneficial effects of this invention are as follows:

[0028] 1. The present invention discloses a method for the resource utilization of semi-coke wastewater, comprising steps such as oil separation and sedimentation, pressure filtration for phenol removal, resin oil and phenol removal, electrolytic oxidation, evaporation and concentration, spray drying, and recrystallization purification. In the pressure filtration for phenol removal step, an appropriate amount of sulfuric acid is added to the wastewater to lower the pH, allowing hydrogen ions to react with phenolic substances in the wastewater to form phenolic precipitates. This early removal of phenols effectively reduces equipment pressure in subsequent processes. Furthermore, the sulfate ions introduced in this step will be reused as raw materials for the generation of ammonium sulfate in subsequent processes.

[0029] In the resin degreasing and phenol removal process, the cleaned resin can treat 50 times its own volume of wastewater each time. Compared with the common extraction-based phenol removal process, this technology is not only more efficient but also effectively reduces costs. By passing steam and organic solvents into the used resin to wash away the adsorbed organic matter, tar precursors can be obtained. Furthermore, the wastewater treated by the pressure filtration phenol removal process has a very low phenol content, greatly improving the efficiency of resin phenol removal, reducing the frequency of resin cleaning, increasing process stability, and lowering costs.

[0030] In the electrolytic oxidation process, the wastewater pH is adjusted to 2-3 by the initial pressure filtration phenol removal process. The clarified wastewater obtained through this process has excellent stability, preventing precipitation and reduced electrolysis efficiency due to pH fluctuations during electrolytic oxidation. Furthermore, adjusting the wastewater pH to 2-3 and setting the current to 5.6A in the electrolytic oxidation process enhances the activity of the electrolytic reaction, improving the efficiency of electrolytic flotation. In particular, the generation of dense bubbles during electrolysis is clearly observed, significantly improving the flotation effect and facilitating pollutant removal. This is because when direct current passes through the wastewater, a series of electrochemical reactions occur, such as a reduction reaction at the cathode, producing small-diameter bubbles with a large specific surface area. These bubbles can adsorb tiny particles, colloidal substances, and charged particles in the wastewater. As these bubbles rise, they carry the adsorbed pollutants to the surface, ultimately forming scum, thus separating the pollutants from the water. Electrolysis may also produce a series of substances with oxidizing or reducing properties, such as hydroxyl radicals, which can oxidize and decompose organic matter in wastewater, thereby reducing COD and BOD of wastewater.

[0031] In the evaporation and concentration process, the pH of the wastewater is adjusted to 4-5, primarily to promote the formation of ammonium sulfate. At a pH of 4-5, ammonia nitrogen exists as ammonia ions, which facilitates its combination with the sulfuric acid introduced in the phenol removal process via pressure filtration to form ammonium sulfate. Within this pH range, less ammonia escapes, which is beneficial for subsequent biological or chemical treatment, making the entire wastewater treatment process more efficient. The condensate generated during evaporation in this step undergoes biochemical-MBR treatment, and is recycled again once it meets the standards. Water vapor generated in the spray drying tower-fluidized bed is introduced into the VOC treatment system for harmless treatment before being discharged.

[0032] 2. The resource utilization method for semi-coke wastewater disclosed in this invention adjusts the pH of the wastewater by adding sulfuric acid and ammonia, and then reduces COD and BOD through scientific experimental methods. This improves upon the shortcomings of the original semi-coke wastewater treatment technology in the oil removal process. By adding a large amount of sulfuric acid in advance to adjust the pH to a lower level, phenolic substances are precipitated in advance, thereby reducing safety hazards in subsequent processes and improving the system's treatment efficiency for semi-coke wastewater. Simultaneously, while adjusting the pH, sulfuric acid and ammonia can recover ammonia and phenolic substances from the wastewater, yielding phenolic tar and ammonium sulfate byproducts, achieving resource recovery and generating good economic benefits. Furthermore, the distillate is treated using a biochemical-MBR process, enabling water reuse.

[0033] Other advantages, objectives, and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination, or may be learned from practice of the invention. The objectives and other advantages of the invention can be realized and obtained through the following description. Attached Figure Description

[0034] To make the objectives, technical solutions, and advantages of the present invention clearer, the preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, wherein:

[0035] Fig. 1 This is a framework diagram of the semi-coke wastewater treatment process of the present invention;

[0036] Fig. 2 This is a flow chart of the semi-coke wastewater treatment process of the present invention. Detailed Implementation

[0037] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0038] like Figs. 1-2 The method for resource utilization of semi-coke wastewater, as shown, includes steps such as oil separation and sedimentation, phenol removal by pressure filtration, oil and phenol removal by resin, electrolytic oxidation, evaporation and concentration, spray drying, and recrystallization purification. The treatment system involved includes an oil separation sedimentation tank, a flocculation sedimentation tank, a filter press, a transfer tank, a resin oil and phenol removal unit, an electrolytic oxidation unit, an evaporator and concentrator, a centrifuge, a spray drying tower-rotary kiln, a dissolving and stirring tank, a VOC treatment system, an evaporator and crystallizer, and a broom-type dryer. Specifically:

[0039] S1, oil separation sedimentation

[0040] In an oil-water separation sedimentation tank, a demulsifier is added and allowed to stand, and the lower layer yields wastewater with low oil content.

[0041] S2, Filtration treatment

[0042] The slag-removing wastewater obtained in step S1 is placed in a flocculation sedimentation tank, sulfuric acid is added to adjust the pH to 6-8, and then polyaluminum chloride (PAC) flocculant is added and stirred thoroughly. Solid-liquid separation is carried out in a filter press to finally obtain wastewater with flocculent pollutants removed.

[0043] S3, Pressure filtration to remove phenol

[0044] The wastewater obtained in step S2 is treated by adding sulfuric acid to adjust the pH to 0-1.5. After the phenol is allowed to settle, the solid phenol and liquid wastewater are separated by a filter press.

[0045] Experiments have shown that at a pH of 0-1.5, hydrogen ions react with phenolic substances in wastewater to form phenolic precipitates. Removing more phenols in advance can reduce the equipment pressure in subsequent processes.

[0046] S4. Resin oil and phenol removal: The wastewater obtained in step S3 is passed sequentially through oil removal resin and phenol removal resin columns to further remove oil and phenol substances from the wastewater, ultimately obtaining relatively clear wastewater.

[0047] This step benefits from the pre-treatment of phenolic substances in process S3, significantly improving resin efficiency. The washed resin can process 50 times its own volume of wastewater each time. Compared to common extraction-based phenol removal, this process is not only more efficient but also significantly reduces costs. During resin washing, steam and organic solvents are sequentially introduced into the resin column to remove adsorbed organic matter. The resulting eluent is then used as a tar byproduct.

[0048] S5, Electrolytic Oxidation

[0049] Add an appropriate amount of ammonia to the wastewater obtained in step S4 to adjust the pH value to 2-3, and then carry out electrolytic oxidation under a current of 5.6A. After standing and separating the liquid, further remove the organic matter in the wastewater.

[0050] In some embodiments, after repeated experiments to find the optimal parameter conditions, we adjusted the pH to 2-3 and set the current to 5.6A. Under these parameters, the activity of the electrolytic reaction is improved, which helps to enhance the efficiency of electrolytic flotation. In particular, the generation of dense bubbles can be clearly observed during the electrolysis process, which greatly helps to improve the flotation effect and facilitates the removal of pollutants. This is because when direct current passes through wastewater, a series of electrochemical reactions will occur, such as the reduction reaction at the cathode, which produces small-diameter bubbles with a large specific surface area. These bubbles can adsorb tiny particles, colloidal substances, and charged particles in the wastewater. As these bubbles rise, they carry the adsorbed pollutants to the surface, eventually forming scum, thereby achieving the separation of pollutants from water. The electrolysis process may also generate a series of substances with oxidizing or reducing properties, such as hydroxyl radicals, which can oxidize and decompose organic matter in wastewater, thereby reducing the COD and BOD of the wastewater and increasing the BOD / COD ratio.

[0051] S6, Evaporation and Concentration

[0052] Add ammonia to the wastewater obtained in step S5 to adjust the pH to 4-5, and then introduce it into an evaporator to obtain a concentrated ammonium sulfate solution.

[0053] In some cases, we adjust step S5 to bring the wastewater pH to 4-5. In an environment with a pH of 4-5, ammonia nitrogen exists in the form of ammonia ions, resulting in less ammonia gas escaping. This facilitates subsequent biological-MBR treatment, making the entire wastewater treatment process more efficient. Simultaneously with obtaining ammonium sulfate, the condensate generated during evaporation and crystallization in this step undergoes biochemical treatment and testing. If it meets the standards, it is recycled again.

[0054] S7, Spray drying - rotary kiln treatment

[0055] The ammonium sulfate concentrate obtained in step S6 is pumped into a spray drying tower, where hot air at 200-400℃ evaporates the water. The exhaust gas is discharged into the VOC treatment system. The resulting solid enters a rotary kiln, where hot air at 250-300℃ is used to heat-treat the ammonium sulfate solid, making the organic matter adhering to the surface of the ammonium sulfate solid insoluble in water. This step yields crude ammonium sulfate; the water vapor generated in the spray drying tower-fluidized bed is then introduced into the VOC treatment system for harmless treatment before being discharged.

[0056] S8, Dissolve-Filter

[0057] The crude ammonium sulfate obtained in step S7 is added to a dissolving and stirring tank, and then an insoluble organic and inorganic substance is removed by a filter press until an ammonium sulfate solution with low impurity content is obtained.

[0058] S9, Evaporation crystallization-drying

[0059] The ammonium sulfate solution obtained in step S8 is subjected to evaporation-centrifugation-drying to obtain byproduct ammonium sulfate. Moist ammonium sulfate solid is obtained in a centrifuge and then dried using a rake dryer to obtain the byproduct ammonium sulfate solid.

[0060] S10, Biochemical-MBR Treatment

[0061] The distillate obtained in steps S8 and S6 is treated using a biochemical-MBR process to meet the standards for reused water.

[0062] This method for the resource utilization of semi-coke wastewater involves adjusting the pH to a lower level by adding an appropriate amount of sulfuric acid beforehand. This allows phenolic substances to precipitate prematurely, reducing safety hazards in subsequent processes, improving the system's treatment efficiency for semi-coke wastewater, and addressing the shortcomings of the original oil removal process in semi-coke wastewater treatment technology. Adding sulfuric acid and ammonia to the semi-coke wastewater adjusts its pH, thereby reducing COD and BOD through simple experimental methods. Simultaneously, ammonia and phenolic substances can be recovered from the wastewater through pH adjustment with sulfuric acid and ammonia, yielding two byproducts: tar and ammonium sulfate, resulting in significant economic benefits. Furthermore, the distillate is treated using a biological-MBR process to meet reuse standards, achieving water recycling and conserving resources.

[0063] This application explores the optimal pH for pollutant removal by adding sulfuric acid, PAC, and ammonia to semi-coke wastewater. Through experimental methods, it reduces the concentration of pollutants such as COD in the wastewater, improving upon the shortcomings of the original semi-coke wastewater treatment technology's oil removal process and reducing safety hazards during system operation. Simultaneously, sulfuric acid and ammonia, while regulating the pH, can recover ammonia and phenolic substances from the wastewater, yielding tar and ammonium sulfate as byproducts, achieving resource recovery and generating significant economic benefits. Furthermore, the distillate is treated using a biological-MBR process to meet reuse standards, enabling water recycling and conserving resources.

[0064] Example

[0065] 18.3 g of solid was weighed and kept at 250 °C for 2 hours to obtain 15.9241 g of solid. This solid was dissolved in 300 ml of distilled water, sonicated for 2 hours, and allowed to stand overnight. After filtration, a pale yellow solution was obtained, which was then recrystallized. The solution was heated with stirring on a heater. As the solution evaporated, the pale yellow solution darkened in color, and no floating matter was observed. Heating was stopped when crystals precipitated. After cooling to room temperature, the solution was filtered to obtain approximately 9.3 g of white solid. This method can effectively purify ammonium sulfate.

[0066] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for resource utilization of semi-coke wastewater, characterized in that, Includes the following steps: S1. Oil-water separation and sedimentation: The raw wastewater from semi-coke is pumped into the oil-water separation and sedimentation tank, and a demulsifier is added to initially achieve oil-water separation. The lower layer of wastewater is then taken into the next treatment process. S2, Filtration treatment: The oil-removed wastewater obtained in step S1 is placed in a flocculation sedimentation tank, and sulfuric acid is added to adjust the pH of the wastewater to 6-8. Then, wastewater treatment flocculant is added and stirred thoroughly to obtain flocculent solids. Then, solid-liquid separation is carried out in a filter press to obtain flocculated wastewater. S3. Phenol removal by pressure filtration: Add sulfuric acid to the wastewater obtained in step S2 to adjust the pH of the wastewater to ≤1.

5. After standing, use a filter press to further remove phenolic substances from the wastewater in advance, so that the subsequent equipment can work better. S4. Resin oil and phenol removal: The wastewater obtained in step S3 is passed sequentially through columns of oil removal resin and phenol removal resin to further remove oil and phenol substances from the wastewater and finally obtain relatively clear wastewater. S5. Electrolytic oxidation: Ammonia water is added to the wastewater obtained in step S4 to adjust the pH value of the wastewater to 2-3. Then, electrolytic oxidation is carried out under the condition of current range of 3-8A. After standing and separating, the organic matter in the wastewater is further removed. At the same time, the organic matter in the wastewater is oxidized and activated to increase the BOD / COD value of the subsequent distilled water, which facilitates the biochemical treatment of the distilled water. S6. Evaporation and Concentration: Add ammonia water to the wastewater obtained in step S5 to adjust the pH value of the wastewater to 4-5, and then enter the evaporator crystallizer for evaporation and concentration to obtain ammonium sulfate concentrate. The condensate after condensing the distilled water is subjected to biochemical treatment to meet the industrial water standard for reuse. The ammonium sulfate concentrate enters the concentrate transfer tank. S7. Spray drying-rotary kiln: The ammonium sulfate concentrate obtained in step S6 is pumped into the spray drying tower. Hot air at 200-400℃ is used to evaporate the water. The exhaust gas is discharged into the VOC treatment system. The resulting solid enters the rotary kiln. Hot air at 250-300℃ is used to heat-treat the ammonium sulfate solid in the rotary kiln, so that the organic matter adhering to the surface of the ammonium sulfate solid becomes insoluble in water, and crude ammonium sulfate is obtained. S8. Dissolving-Filtration: Add the crude ammonium sulfate obtained in step S7 to a dissolving and stirring tank, and then use a filter press to remove organic and inorganic substances that are insoluble in water, so as to obtain an ammonium sulfate solution with low impurity content. S9. Evaporation and Crystallization-Drying: The ammonium sulfate solution obtained in step S8 is evaporated, centrifuged, and dried to obtain by-product ammonium sulfate; S10, Biochemical-MBR Treatment: The distillate obtained from steps S9 and S6 is subjected to biochemical treatment to meet the standards for reuse.

2. The method for resource utilization of semi-coke wastewater as described in claim 1, characterized in that, In step S1, the raw wastewater from semi-coke is left to stand for more than 24 hours to remove slag, which promotes the full aggregation of solid impurities in the wastewater.

3. The method for resource utilization of semi-coke wastewater as described in claim 1, characterized in that, In step S3, sulfuric acid is added to adjust the pH to 0-1.5, causing phenols in the water to precipitate and removing as many phenols as possible from the wastewater.

4. The method for resource utilization of semi-coke wastewater as described in claim 1, characterized in that, In step S4, wastewater is treated with degreasing resin and phenol removal resin. During the resin cleaning process, steam and organic solvent are sequentially introduced into the resin column to remove the organic matter adsorbed on the resin, resulting in a mixture of organic matter and phenols as a tar byproduct for recycling. The organic solvent is either methanol or ethanol.

5. The method for resource utilization of semi-coke wastewater as described in claim 1, characterized in that, In step S5, the electrolysis oxidation time is 2-4 minutes, the current is adjusted to 4-7 A, and the pH is adjusted to 2-3. Under these parameters, the electrolysis reaction has high activity, which helps to enhance the efficiency of electrolysis oxidation, and the BOD / COD of the subsequent evaporated water is increased to above 0.

3.

6. The method for resource utilization of semi-coke wastewater as described in claim 1, characterized in that, The evaporator used in step S6 is either a multi-effect evaporator or an MVR evaporator. The wastewater from step S5 is evaporated and concentrated until the ammonium sulfate concentration reaches 20-40%. Before the wastewater enters the evaporator, the pH of the feed liquid is controlled at 4-5 to reduce the escape of ammonia.

7. The method for resource utilization of semi-coke wastewater as described in claim 1, characterized in that, Step S7 uses spray drying-rotary kiln, using hot air at 200-400℃ to evaporate the moisture and obtain ammonium sulfate solid. The ammonium sulfate solid is then kept at 200-300℃ in a rotary kiln for 1-3 hours.

8. The method for resource utilization of semi-coke wastewater as described in claim 1, characterized in that, Steps S8 and S9 employ a dissolution-evaporation-crystallization-drying process to finally obtain the byproduct ammonium sulfate.

9. The method for resource utilization of semi-coke wastewater as described in claim 1, characterized in that, The phenolic substances collected in step S3 and the mixture of oil-phenol and organic matter collected in step S4 are recycled into phenolic tar. After steps S1-S9, phenols and ammonium sulfate in semi-coke wastewater are separated to obtain by-products phenolic tar and by-product ammonium sulfate, respectively.

10. The method for resource utilization of semi-coke wastewater as described in claim 1, characterized in that, Step S10 uses a biochemical-MBR system to treat the distillate water, removing ammonia nitrogen and organic matter, so that the distillate water can be recycled and reused.

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