Coal coking high-salt organic wastewater treatment device

Abstract

The application provides a coal coking high-salt organic wastewater treatment device, high-salt organic wastewater is evaporated and concentrated through the setting of an evaporator, secondary steam generated in the concentration process is compressed through a steam compressor and used as a heat source to preheat the organic wastewater entering the evaporator; the crystals generated in the concentration process are discharged into a thickener to be settled and centrifuged through a centrifuge to be output as a final product, the clear liquid in the thickener and the mother liquor after centrifugation are transferred into a mother liquor tank and input into a preheater through a liquid transfer pump to be evaporated and concentrated again, the device is used in cooperation with the above-mentioned equipment, and the device for effectively purifying and treating high-salt organic concentrated water generated in the reverse osmosis process in the wastewater treatment plant of a coking plant is provided.

Description

Technical Field

[0001] This application relates to the field of wastewater treatment technology, and in particular to a device for treating high-salt organic wastewater from coal coking. Background Technology

[0002] In the production processes of coal coking plants and their supporting facilities, wastewater mainly originates from coking sections, coke oven gas comprehensive utilization projects, coal mine dewatering processes, coke oven gas to ethylene glycol production, and coke oven gas to adipic acid production projects. This wastewater is characterized by high salinity and the presence of some organic matter. Under the current environment of green production, the wastewater generated in these sections needs to be treated to meet standards before discharge or reused within the plant to achieve "zero discharge." The existing method involves comprehensively regulating the wastewater from these projects before it enters a pretreatment unit for softening, filtration, and concentration. Reverse osmosis membrane permeate is reused as production water, while high-salinity concentrated water enters an evaporation and crystallization unit for evaporation and crystallization to extract sodium chloride and sodium sulfate for resource utilization.

[0003] The above treatment process achieves 99% reuse of the concentrated brine influent in the production water system. However, approximately 1% of the organic membrane concentrate is not discharged at zero (the treatment capacity is 450 t / h of concentrate, producing 4.8 t / h of organic concentrate). The concentrate produced after organic membrane concentration has high salt content (mainly water-soluble salts containing elements such as calcium, magnesium, and fluorine), high organic matter concentration, and complex water composition. It is not easily biodegraded and is difficult to treat. Conventional wastewater treatment methods (such as filtration and reverse osmosis) are insufficient to meet the technical requirements for the purification of high-concentration organic wastewater. Utility Model Content

[0004] This application provides an apparatus that can effectively purify and treat high-salt organic concentrate generated during the reverse osmosis process in a coking plant when treating wastewater.

[0005] This application provides a coal coking high-salt organic wastewater treatment device, including a wastewater tank, a preheater, an evaporator, a thickener, a centrifuge, and a recovered salt storage silo connected in series.

[0006] The preheater is also connected to a condensate treatment unit;

[0007] The evaporator is also connected to the steam pipeline and the secondary steam compressor, which is in turn connected to the preheater.

[0008] The thickener is also connected in sequence to the mother liquor tank, the transfer pump, and the preheater;

[0009] The centrifuge is also connected to the mother liquor tank.

[0010] Optionally, the mother liquor tank is also connected in sequence to the scraper drying system and the dry material receiving bin.

[0011] Optionally, a wastewater pretreatment device may also be installed between the wastewater tank and the preheater.

[0012] Optionally, the wastewater pretreatment device includes a first reaction tank, a second reaction tank, a third reaction tank, a fourth reaction tank, and a sedimentation tank connected in series.

[0013] The first reaction tank is also connected to a sodium carbonate solution storage tank and a sodium hydroxide storage tank, respectively.

[0014] The second reaction tank is connected to the calcium chloride solution storage tank;

[0015] The third reaction tank is connected to the polyferric sulfate solution storage tank;

[0016] The fourth reaction tank is connected to the flocculant storage tank.

[0017] Optionally, the sedimentation tank includes a pre-settling zone and a settling zone separated by baffles;

[0018] The pre-settling zone and the settling zone are connected by an overflow channel opened at the top of the partition;

[0019] A guide plate parallel to the baffle is provided on the side of the settling zone near the baffle, and the guide plate extends downward from the top of the settling zone;

[0020] A filler layer is provided between the guide plate and the side wall of the settling zone that was originally away from the partition plate;

[0021] The bottom of the packing layer is not lower than the bottom of the guide plate.

[0022] Optionally, the packing layer includes a first inclined plate packing layer and a second inclined plate packing layer arranged sequentially in the vertical direction;

[0023] The first inclined plate filler layer includes multiple spaced and parallel first inclined plates;

[0024] The second inclined plate filler layer includes multiple spaced and parallel second inclined plates.

[0025] Optionally, the tilting directions of the first and second inclined plates are mirror images of each other.

[0026] This application provides a device for treating high-salt organic wastewater from coal coking. The device uses an evaporator to evaporate and concentrate the high-salt organic wastewater. The secondary steam generated during the concentration process is compressed by a steam compressor and used as a heat source to preheat the organic wastewater entering the evaporator. The crystals produced during the concentration process are discharged into a thickener for sedimentation and then centrifuged to produce the final product. The clarified liquid in the thickener and the mother liquor after centrifugation are transferred to a mother liquor tank and pumped back to the preheater for further evaporation and concentration. This device, using the aforementioned equipment, effectively treats high-salt organic wastewater, overcoming the limitations of conventional filtration and reverse osmosis methods in meeting the technical requirements for purifying high-concentration organic wastewater. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 A schematic diagram of a coal coking high-salt organic wastewater treatment device provided in an embodiment of this application;

[0029] Figure 2 A schematic diagram of a coal coking high-salt organic wastewater treatment device provided in another embodiment of this application;

[0030] Figure 3 A schematic diagram of a coal coking high-salt organic wastewater treatment device provided in yet another embodiment of this application;

[0031] Figure 4 A schematic diagram of a wastewater pretreatment device provided in an embodiment of this application;

[0032] Figure 5 This is a schematic diagram of the sedimentation tank provided in one embodiment of this application.

[0033] Explanation of reference numerals in the attached figures:

[0034] 1. Wastewater tank; 2. Preheater; 3. Evaporator; 4. Thickener; 5. Centrifuge; 6. Recycled salt storage tank; 7. Mother liquor tank; 8. Scraper drying system; 9. Wastewater pretreatment device; 10. Steam pipeline; 20. Secondary steam compressor; 21. Condensate treatment device; 30. Transfer pump; 81. Dry material receiving tank; 91. First reaction tank; 92. Second reaction tank; 93. Third reaction tank; 94. Fourth reaction tank; 95. Sedimentation tank; 911. Sodium carbonate solution storage tank; 912. Sodium hydroxide storage tank; 921. Calcium chloride solution storage tank; 931. Polyferric sulfate solution storage tank; 941. Flocculant storage tank; 951. Baffle plate; 952. Baffle plate; 953. Packing layer; 9501. Overflow trough; 9531. First inclined plate packing layer; 9532. Second inclined plate packing layer. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions in the embodiments of this application are described clearly and completely below. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are also within the scope of protection of this application.

[0036] like Figure 1 As shown, this application provides a coal coking high-salt organic wastewater treatment device, including a wastewater tank 1, a preheater 2, an evaporator 3, a thickener 4, a centrifuge 5, and a recovered salt storage silo 6 connected in series.

[0037] The preheater 2 is also connected to the condensate treatment device 21;

[0038] Evaporator 3 is also connected to steam pipeline 10 and secondary steam compressor 20 respectively, and secondary steam compressor 20 is also connected to preheater 2;

[0039] The thickener 4 is also connected in sequence to the mother liquor tank 7, the transfer pump 30 and the preheater 2;

[0040] Centrifuge 5 is also connected to mother liquor tank 7.

[0041] During use, the high-salt organic wastewater output from the reverse osmosis section is temporarily stored in wastewater tank 1 and then fed into preheater 2 (preheater 2 can be a shell and tube heat exchanger or a plate heat exchanger).

[0042] Wastewater is heated to a boiling state in preheater 2 using compressed secondary steam. The boiling wastewater is then transferred to evaporator 3, where it is further heated and concentrated using high-temperature, high-pressure steam output from steam pipeline 10. In evaporator 3, the secondary steam generated from the evaporation of wastewater is fed into secondary steam compressor 20. Secondary steam compressor 20 compresses the low-temperature secondary steam generated from the evaporation of materials, increasing the pressure, temperature, and enthalpy of the secondary steam and converting electrical energy into sensible heat of steam. The secondary steam compressed by secondary steam compressor 20 is sent to preheater 2 as heating steam to keep the wastewater liquid at a boiling state, while the heating steam itself condenses into condensate (condensate TDS≤600mg / L). The steam condensate enters condensate treatment device 21 (condensate treatment device 21 is a front-end equalization tank or a recycled water tank).

[0043] The heated material is vaporized and concentrated in evaporator 3, producing crystals that are continuously discharged into thickener 4. Due to gravity, the crystals settle to the bottom of thickener 4 and are then transferred to centrifuge 5 to remove moisture. The dehydrated material, i.e., salt particles, is transferred to recovery salt storage silo 6 and bagged for external disposal as the final product discharge system. The supernatant at the top of thickener 4 overflows or is pumped into mother liquor tank 7 for collection.

[0044] This application provides a coal coking high-salt organic wastewater treatment device. The device uses an evaporator 3 to evaporate and concentrate the high-salt organic wastewater. The secondary steam generated during the concentration process is compressed by a steam compressor 20 and used as a heat source to preheat the organic wastewater entering the evaporator 3. The crystals generated during the concentration process are discharged into a thickener 4 for sedimentation and then centrifuged by a centrifuge 5 to produce the final product. The clear liquid in the thickener 4 and the mother liquor after centrifugation are transferred to a mother liquor tank 7 and pumped back to the preheater 2 by a transfer pump 30 for further evaporation and concentration. This device, using the aforementioned equipment, effectively treats high-salt organic wastewater, overcoming the limitations of conventional filtration and reverse osmosis methods in meeting the technical requirements for high-concentration organic wastewater purification.

[0045] like Figure 2 As shown, optionally, the mother liquor tank 7 is also connected in sequence to the scraper drying system 8 and the dry material receiving bin 81.

[0046] In this application, after the mother liquor is repeatedly circulated and concentrated, the concentration of organic matter in it increases, which affects the generation and growth of crystal nuclei. The high-concentration mother liquor is discharged into the scraper drying system 8, dried by steam heating, and then transferred to the dry material receiving bin 81 and bagged for shipment.

[0047] like Figure 3 As shown, optionally, a wastewater pretreatment device 9 is also provided between the wastewater tank 1 and the preheater 2.

[0048] In this application, because the wastewater contains high levels of scale-forming ions such as calcium and magnesium, these ions will form water during evaporation in evaporator 3, causing scaling and blockage of the tubes and other structures in evaporator 3. Therefore, the wastewater needs to be decalcified and demagnesified before being fed into evaporator 3 for evaporation and concentration. Thus, the wastewater is first fed into wastewater pretreatment device 9 for decalcification and demagnesification treatment.

[0049] like Figure 4 As shown, optionally, the wastewater pretreatment device 9 includes a first reaction tank 91, a second reaction tank 92, a third reaction tank 93, a fourth reaction tank 94 and a sedimentation tank 95 connected in series.

[0050] The first reaction tank 91 is also connected to a sodium carbonate solution storage tank 911 and a sodium hydroxide storage tank 912, respectively.

[0051] The second reaction tank 92 is connected to the calcium chloride solution storage tank 921;

[0052] The third reaction tank 93 is connected to the polyferric sulfate solution storage tank 931;

[0053] The fourth reaction tank 94 is connected to the flocculant storage tank 941.

[0054] During treatment, wastewater first enters the first reaction tank 91. Sodium carbonate and sodium hydroxide solutions are added to the wastewater through sodium carbonate solution storage tank 911 and sodium hydroxide storage tank 912. Calcium ions and carbonate ions combine to form calcium carbonate (CaCO3) precipitate, while carbonate ions combine with magnesium ions to form magnesium carbonate (MgCO3) precipitate. However, magnesium carbonate has lower solubility in water, but slightly higher than calcium carbonate. To more effectively remove magnesium ions, excess sodium hydroxide is added to the water, maintaining the pH between 10.8 and 11.5, allowing magnesium carbonate to further react and form sparingly soluble magnesium hydroxide. Mg(OH)2 forms a white precipitate, further removing magnesium ions. The organic wastewater, after calcium and magnesium removal in the first reaction tank 91, flows into the second reaction tank 92. Calcium chloride solution is added through calcium chloride solution storage tank 921. Calcium chloride (CaCl2) dissolves in the water, releasing calcium ions (Ca²⁺). When calcium ions combine with fluoride ions (F⁻) in water, they form insoluble calcium fluoride (CaF₂) precipitate, thus reducing the fluoride content in the water. During the defluorination process, the pH of the wastewater should be maintained at approximately 11 ± 0.2 to avoid introducing excessive calcium ions into the wastewater through the addition of calcium chloride. The colloidal particles of calcium carbonate, magnesium hydroxide, and calcium fluoride produced in the above reaction flow together with the water into the third reaction tank 93. Polyferric sulfate solution is added using the polyferric sulfate solution storage tank 931. These colloidal particles undergo a series of chemical and physical reactions with polyferric sulfate (PFS) in the water. Polyferric sulfate undergoes hydrolysis in water, generating various positively charged dimers and polymers. These polynuclear hydroxyl complexes have large molecular weights and multiple positive charges, enabling them to neutralize the charge of negatively charged colloidal particles (such as suspended solids and colloids) in the water. Colloidal particles in water usually carry a negative charge. The positively charged complexes generated by the hydrolysis of iron ions in polyferric sulfate can neutralize the negative charge of the colloidal particles, compress their electric double layer, reduce the potential of the colloidal particles, thereby destabilizing and aggregating them.

[0055] The wastewater after coagulation with polyferric sulfate enters the fourth reaction tank 94. A flocculant (an aqueous solution of polyacrylamide is used in this application) is added to the flocculant storage tank 941, causing the hydrolysis products of the agent to react with colloidal particles in the water to form flocs. These flocs continuously contact and collide, growing into dense, easily settling flocs. Simultaneously, a stirring device is provided to shear the suspended solids in the water, reforming them into large, easily settling flocs.

[0056] (1) Principle of calcium and magnesium ion removal: Concentrated organic wastewater is fed into the first reaction tank 91. Sodium carbonate and sodium hydroxide are added to remove hardness from the wastewater. Sodium carbonate (Na₂CO₃) is an alkaline salt. When added to hard water, a double displacement reaction occurs. Sodium carbonate dissociates in water into sodium ions (Na⁺) and carbonate ions (CO₃²⁻). Calcium ions and carbonate ions combine to form calcium carbonate (CaCO₃) precipitate.

[0057] The reaction equation is as follows: Ca²⁺ + CO₃²⁻ — CaCO₃↓

[0058] Calcium carbonate is a white solid that is insoluble in water. It will precipitate out of the water, thereby removing calcium ions from the water.

[0059] The reaction for the removal of magnesium ions is as follows:

[0060] The reaction equation is as follows: Mg²⁺ + CO₃²⁻ → MgCO₃↓

[0061] Carbonate ions combine with magnesium ions to form magnesium carbonate (MgCO3) precipitate. However, magnesium carbonate has low solubility in water, but slightly higher than calcium carbonate. To remove magnesium ions more effectively, excess sodium hydroxide is added to the water, and the pH is controlled between 10.8 and 11.5 to allow the magnesium carbonate to react further.

[0062] The reaction equation is as follows: MgCO3 + 2NaOH → Mg(OH)2↓ + Na2CO3

[0063] The resulting magnesium hydroxide Mg(OH)2 is a more insoluble white precipitate, thus removing magnesium ions more thoroughly.

[0064] Similarly, adding NaOH and HCO3 to water - The reaction produces CaCO3 precipitate, removing calcium hardness; excess NaOH will react with Mg 2+ The reaction produces Mg(OH)2 precipitate, thereby removing Mg. 2+ .

[0065] (2) Fluoride ion removal principle: The concentrated organic water, after calcium and magnesium ions have been removed, flows into the second reaction tank 92 by gravity. Calcium chloride solution is added, and calcium chloride (CaCl2) dissolves in the water, releasing calcium ions (Ca²⁺). When these calcium ions combine with fluoride ions (F⁻) in the water, they form insoluble calcium fluoride (CaF2) precipitate.

[0066] The reaction equation is as follows: Ca²⁺ + 2F⁻ → CaF₂↓

[0067] Because calcium fluoride has low solubility, the resulting precipitate can be removed through solid-liquid separation, thereby reducing the fluoride content in the water. Applying the common ion effect, calcium chloride can further reduce the solubility of calcium fluoride during actual treatment. By increasing the concentration of calcium ions, more fluoride ions can be precipitated.

[0068] (3) The colloidal particles of calcium carbonate, magnesium hydroxide, and calcium fluoride produced by the above reaction flow by gravity into the third reaction tank 93, where a coagulant (polyferric sulfate, PFS) is added. The colloidal particles undergo a series of chemical and physical reactions with the polyferric sulfate (PFS) in the water. The polyferric sulfate undergoes hydrolysis in the water, generating various positively charged dimers and polymers. These polynuclear hydroxyl complexes have large molecular weights and multiple positive charges, enabling them to neutralize the charge of negatively charged colloidal particles (such as suspended solids and colloids) in the water. Colloidal particles in water are usually negatively charged; the positively charged complexes generated by the hydrolysis of iron ions in the polyferric sulfate can neutralize the negative charge of the colloidal particles, compress their electric double layer, and reduce the potential of the colloidal particles, thereby destabilizing and aggregating them.

[0069] (4) The concentrated organic wastewater after coagulation with polyferric sulfate enters the fourth reaction tank 94, where flocculant (polyacrylamide PAM) is added. The flocculation process involves the reaction of the hydrolysis products of the agent with colloidal particles in the water to form flocs. Through continuous contact and collision, these flocs grow into dense, easily settling flocs. In the reaction tank, a turbine mixer operates at a high speed of 10 times the circulation rate, shearing the suspended solids in the water and reforming them into large, easily settling flocs. Simultaneously, by effectively controlling the sludge return flow, a suitable sludge concentration is maintained in the reaction tank, which is beneficial for flocculation and saves on the amount of flocculant used.

[0070] like Figure 5 As shown, optionally, the sedimentation tank 95 includes a pre-settling zone and a settling zone separated by a partition 951;

[0071] The pre-settling zone and the settling zone are connected by an overflow channel 9501 opened on the upper part of the partition 951;

[0072] A guide plate 952 parallel to the partition 951 is provided on the side of the settling zone near the partition 951, and the guide plate 952 extends downward from the top of the settling zone.

[0073] A filler layer 953 is provided between the guide plate 952 and the side wall of the settling zone away from the partition plate 951;

[0074] The bottom of the packing layer 953 is not lower than the bottom of the guide plate 952.

[0075] In this application, during use, the flocculent wastewater mixture obtained by flocculation in the fourth reaction tank 94 enters the pre-settling zone of the sedimentation tank 95. Due to their high density, large suspended solids cannot turn over the overflow channel 9501 and settle rapidly in the pre-settling zone, while small flocculents with lower density are carried by the water flow and enter the settling zone through the overflow channel 9501. The flocculents are intercepted and captured when passing through the packing layer 953, and the supernatant is output from the top of the settling zone into the preheater 2 (the preheater 2 can be a shell and tube heat exchanger or a plate heat exchanger).

[0076] like Figure 5 As shown, optionally, the packing layer 953 includes a first inclined plate packing layer 9531 and a second inclined plate packing layer 9532 arranged sequentially in the vertical direction;

[0077] The first inclined plate filler layer 9531 includes a plurality of spaced and parallel first inclined plates;

[0078] The second inclined plate filler layer 9532 includes multiple spaced and parallel second inclined plates.

[0079] In this application, the first inclined plate and the second inclined plate have different inclination directions. For example, the inclination directions of the first inclined plate and the second inclined plate are mirror images of each other. In this way, the channel between the first inclined plate and the second inclined plate is zigzag-shaped. When the flocs pass through the packing layer 953, they are intercepted and captured by the inclined plates in the first inclined plate packing layer 9531 and the second inclined plate packing layer 9532. The floc particles entrained in the water flow settle when they collide with the inclined plates, which is conducive to the settling of particles.

[0080] In this application, the angle between the first and second inclined plates and the horizontal plane is 30° to 60°. This means that when the two plates are mirror-distributed, they reduce resistance to water flow and also intercept floc particles.

[0081] A coal coking high-salt organic wastewater treatment device, the working process of which is as follows:

[0082] During operation, the high-salt organic wastewater output from the reverse osmosis section is temporarily stored in wastewater tank 1. Due to the high content of scale-forming ions such as calcium and magnesium in the wastewater, these ions will form water during evaporation in evaporator 3, causing scaling and clogging of the tubes and other structures in evaporator 3. Therefore, the wastewater needs to be decalcified and demagnesified before being fed into evaporator 3 for evaporation and concentration. Thus, the wastewater is first fed into wastewater pretreatment device 9 for treatment. During treatment, the wastewater first enters the first reaction tank 91. Sodium carbonate solution and sodium hydroxide solution are added to the wastewater through sodium carbonate solution storage tank 911 and sodium hydroxide storage tank 912. Calcium ions and carbonate ions combine to form calcium carbonate (CaCO3) precipitate, and carbonate ions combine with magnesium ions to form magnesium carbonate (MgCO3) precipitate. However, magnesium carbonate has lower solubility in water, but slightly higher solubility than calcium carbonate. To more effectively remove magnesium ions, excess sodium hydroxide is added to the water, maintaining the pH between 10.8 and 11.5. This allows magnesium carbonate to react further, forming insoluble magnesium hydroxide, which is a white precipitate (Mg(OH)₂), thus further removing magnesium ions. The organic wastewater, after calcium and magnesium removal in the first reaction tank 91, flows into the second reaction tank 92. Calcium chloride solution is added through the calcium chloride solution storage tank 921. Calcium chloride (CaCl₂) dissolves in the water, releasing calcium ions (Ca²⁺). When these calcium ions combine with fluoride ions (F⁻) in the water, they form insoluble calcium fluoride (CaF₂) precipitate, reducing the fluoride content in the water. During the defluorination process, the pH of the wastewater should be maintained at approximately 11 ± 0.2 to avoid introducing excessive calcium ions into the wastewater with the addition of calcium chloride. The colloidal particles of calcium carbonate, magnesium hydroxide, and calcium fluoride produced in the above reaction flow together with water into the third reaction tank 93. Polyferric sulfate solution is added using the polyferric sulfate solution storage tank 931. These colloidal particles undergo a series of chemical and physical reactions with polyferric sulfate (PFS) in the water. Polyferric sulfate undergoes hydrolysis in water, generating various positively charged dimers and polymers. These polynuclear hydroxyl complexes have large molecular weights and multiple positive charges, enabling them to neutralize the charge of negatively charged colloidal particles (such as suspended solids and colloids) in the water. Colloidal particles in water are usually negatively charged; the positively charged complexes generated by the hydrolysis of iron ions in polyferric sulfate can neutralize the negative charge of the colloidal particles, compress their electric double layer, and lower the potential of the colloidal particles, thereby destabilizing and aggregating them.

[0083] The wastewater after coagulation with polyferric sulfate enters the fourth reaction tank 94. A flocculant (an aqueous solution of polyacrylamide is used in this application) is added to the flocculant storage tank 941, causing the hydrolysis products of the agent to react with colloidal particles in the water to form flocs. These flocs continuously contact and collide, growing into dense, easily settling flocs. Simultaneously, a stirring device is provided to shear the suspended solids in the water, reforming them into large, easily settling flocs.

[0084] The flocculated wastewater mixture obtained through flocculation enters the pre-settling zone of sedimentation tank 95. Due to their high density, large suspended particles cannot turn over the overflow channel 9501 and settle rapidly in the pre-settling zone. Meanwhile, the smaller flocs with lower density are carried by the water flow and enter the settling zone through the overflow channel 9501. When the flocs pass through the packing layer 953, they are intercepted and captured by the inclined plates in the first inclined plate packing layer 9531 and the second inclined plate packing layer 9532. The supernatant is then output from the top of the settling zone into the preheater 2 (the preheater 2 can be a shell and tube heat exchanger or a plate heat exchanger).

[0085] Wastewater is heated to a boiling state in preheater 2 using compressed secondary steam. The boiling wastewater is then transferred to evaporator 3, where it is further heated and concentrated using high-temperature, high-pressure steam output from steam pipeline 10. In evaporator 3, the secondary steam generated from the evaporation of wastewater is fed into secondary steam compressor 20. Secondary steam compressor 20 compresses the low-temperature secondary steam generated from the evaporation of materials, increasing the pressure, temperature, and enthalpy of the secondary steam and converting electrical energy into sensible heat of steam. The secondary steam compressed by secondary steam compressor 20 is sent to preheater 2 as heating steam to keep the wastewater liquid at a boiling state, while the heating steam itself condenses into condensate (condensate TDS≤600mg / L). The steam condensate enters condensate treatment device 21 (condensate treatment device 21 is a front-end equalization tank or a recycled water tank).

[0086] The heated material is vaporized and concentrated in evaporator 3, producing crystals that are continuously discharged into thickener 4. Due to gravity, the crystals settle to the bottom of thickener 4 and are then transferred to centrifuge 5 to remove moisture. The dehydrated material, i.e., salt particles, is transferred to recovery salt storage silo 6 and bagged for transport as the final product. The supernatant overflowing from the top of thickener 4 or pumped into mother liquor tank 7 is then pumped into preheater 2 by transfer pump 30, where it is combined with wastewater from wastewater tank 1 for preheating. After multiple cycles of concentration, the organic matter concentration in the mother liquor increases, affecting crystal nuclei formation and growth. The high-concentration mother liquor is discharged into scraper drying system 8, where it is dried by steam heating and then transferred to dry material receiving silo 81 and bagged for transport.

[0087] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A device for treating high-salt organic wastewater from coal coking, characterized in that, It includes a wastewater tank (1), a preheater (2), an evaporator (3), a thickener (4), a centrifuge (5), and a recycled salt storage silo (6) connected in series. The preheater (2) is also connected to the condensate treatment device (21); The evaporator (3) is also connected to the steam pipeline (10) and the secondary steam compressor (20), and the secondary steam compressor (20) is also connected to the preheater (2); The thickener (4) is also connected in sequence to the mother liquor tank (7), the transfer pump (30) and the preheater (2); The centrifuge (5) is also connected to the mother liquor tank (7).

2. The coal coking high-salt organic wastewater treatment device according to claim 1, characterized in that, The mother liquor tank (7) is also connected in sequence to the scraper drying system (8) and the dry material receiving bin (81).

3. The coal coking high-salt organic wastewater treatment device according to claim 1, characterized in that, A wastewater pretreatment device (9) is also provided between the wastewater tank (1) and the preheater (2).

4. The coal coking high-salt organic wastewater treatment device according to claim 3, characterized in that, The wastewater pretreatment device (9) includes a first reaction tank (91), a second reaction tank (92), a third reaction tank (93), a fourth reaction tank (94), and a sedimentation tank (95) connected in series. The first reaction tank (91) is also connected to a sodium carbonate solution storage tank (911) and a sodium hydroxide storage tank (912), respectively; The second reaction tank (92) is connected to the calcium chloride solution storage tank (921); The third reaction tank (93) is connected to the polyferric sulfate solution storage tank (931); The fourth reaction tank (94) is connected to the flocculant storage tank (941).

5. The coal coking high-salt organic wastewater treatment device according to claim 4, characterized in that, The sedimentation tank (95) includes a pre-settling zone and a settling zone separated by a partition (951); The pre-settling zone and the settling zone are connected by an overflow channel (9501) opened on the upper part of the partition (951); A guide plate (952) parallel to the partition plate (951) is provided on the side of the settling zone near the partition plate (951), and the guide plate (952) extends downward from the top of the settling zone. A filler layer (953) is provided between the guide plate (952) and the side wall of the settling zone that is originally away from the partition plate (951). The bottom of the filler layer (953) is not lower than the bottom of the guide plate (952).

6. The coal coking high-salt organic wastewater treatment device according to claim 5, characterized in that, The packing layer (953) includes a first inclined plate packing layer (9531) and a second inclined plate packing layer (9532) arranged in sequence in the vertical direction; The first inclined plate filler layer (9531) includes a plurality of spaced and parallel first inclined plates; The second inclined plate filler layer (9532) includes a plurality of spaced and parallel second inclined plates.

7. The coal coking high-salt organic wastewater treatment device according to claim 6, characterized in that, The tilting directions of the first inclined plate and the second inclined plate are mirror images of each other.

Images