Concentrated mother liquor reduction treatment device after evaporation and salt extraction of coking wastewater
By designing a treatment device for reducing the volume of concentrated mother liquor after evaporation and salt extraction of coking wastewater, the sedimentation separation and chemical sedimentation of concentrated mother liquor were achieved, solving the problems of complex composition of concentrated mother liquor and foaming and corrosion caused by direct evaporation, and improving the water recycling rate and coke quality.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-24
- Publication Date
- 2026-03-13
AI Technical Summary
Coking wastewater is difficult to treat. The concentrated mother liquor has a complex composition. Direct evaporation leads to foaming and corrosion, and the addition of concentrated mother liquor to coking coal affects the quality of coke.
The design includes a wastewater deep treatment tank, a concentrated mother liquor treatment system, and an evaporator for salt extraction. The system removes COD components and F ions through sedimentation separation and chemical sedimentation, and converts the remaining salt into solid salt to prevent accumulation.
It reduces the salt content in sludge, avoids adverse effects on coke quality, solves the foaming and corrosion problems caused by direct evaporation of concentrated mother liquor, and improves water recycling rate.
Smart Images
Figure CN223991012U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of coking wastewater treatment technology, specifically to a device for reducing the volume of concentrated mother liquor after evaporation and salt extraction of coking wastewater. Background Technology
[0002] Coking wastewater is a type of wastewater that is generated in large quantities and is extremely difficult to treat during the coking process. Its composition is complex, containing not only toxic and highly toxic substances such as phenols and cyanides, but also aromatic hydrocarbons, polycyclic aromatic hydrocarbons, and heterocyclic aromatic hydrocarbons that are difficult to biodegrade. It also contains high levels of suspended solids, chloride, sulfate, fluorine, calcium, and magnesium ions. It is a high-concentration organic industrial wastewater that is difficult to treat and is one of the environmental challenges in the coking industry.
[0003] Zero-discharge technology for coking wastewater is a cutting-edge technology that has developed in the coking industry in recent years. The coking wastewater generated during the coking process is first treated by a wastewater treatment plant, such as... Figure 2 As shown, after most of the harmful components in the water are decomposed, the resulting wastewater enters the advanced wastewater treatment process, where it is treated with chemical agents or activated carbon. The produced water is then recycled and reused through membrane filtration, evaporation, and other methods. The remaining mixed salts are disposed of in compliance with regulations or further refined by salt separation. The sludge produced by the wastewater treatment unit and the advanced wastewater treatment process is concentrated, filtered, and dried before being sent to coal blending. Evaporation of coking wastewater often employs multi-effect evaporation and MVR evaporation. During the evaporation process, a small amount of concentrated mother liquor containing salt is obtained. This concentrated mother liquor has a complex composition, containing a large amount of COD components and F ions. Direct evaporation would cause severe foaming and corrosion, and there is currently no effective treatment method.
[0004] Currently, the coking industry treats concentrated mother liquor by mixing it with coking coal and sending it to the coke oven for further processing. This method has the following drawbacks:
[0005] (1) The concentrated mother liquor after concentration is saturated brine with a high salt content. When it is mixed into coking coal for processing, a large amount of salt will remain in the coke, causing the coke's resistance to breakage, abrasion, ash content, sodium content and other indicators to deteriorate, which seriously affects the quality of the coke.
[0006] (2) The concentrated mother liquor contains a certain amount of magnesium chloride. When magnesium chloride is heated during the coking process, it decomposes to release hydrogen chloride gas, which reacts with indene and other substances in the coke oven gas to generate organic chlorides, causing the chloride ion index in the crude benzene product to exceed the standard, thus affecting the product quality of the gas purification device.
[0007] Therefore, there is an urgent need to design a treatment device for reducing the volume of concentrated mother liquor after evaporation and salt extraction of coking wastewater, in order to solve the problems of difficult coking wastewater treatment, complex composition of concentrated mother liquor after concentration, and serious foaming and corrosion caused by direct evaporation of concentrated mother liquor. Utility Model Content
[0008] In view of the problems existing in the prior art, the purpose of this utility model is to provide a device for reducing the amount of concentrated mother liquor after evaporation and salt extraction of coking wastewater.
[0009] The technical solution adopted by this utility model to solve its technical problem is: a device for reducing the volume of concentrated mother liquor after evaporation and salt extraction of coking wastewater, including a wastewater deep treatment tank, a concentrated mother liquor treatment system and an evaporator. The inlet of the wastewater deep treatment tank is connected to the coking wastewater discharge pipe. The wastewater discharged from the wastewater deep treatment tank flows into the concentrated mother liquor treatment system and the evaporator through the pipeline. The concentrated mother liquor treatment system is located between the wastewater deep treatment tank and the evaporator. The evaporator is connected to the wastewater deep treatment tank and the concentrated mother liquor treatment system through the pipeline. The evaporator is equipped with a water recovery chamber and a solid salt collection chamber.
[0010] Specifically, the wastewater deep treatment tank is directly connected to the coking wastewater discharge pipe, and the wastewater deep treatment tank is equipped with an inlet, an outlet, and a sludge discharge outlet.
[0011] Specifically, the concentrated mother liquor treatment system includes a coagulation tank, a primary sedimentation tank, a reaction tank, a secondary sedimentation tank, and a concentration tank. The coagulation tank is connected to the wastewater deep treatment tank through a coagulation tank connecting pipe. The reaction tank is located between the primary sedimentation tank and the secondary sedimentation tank. The reaction tank absorbs the wastewater discharged from the primary sedimentation tank and the sludge discharged from the wastewater deep treatment tank. The wastewater and sludge discharged from the reaction tank are discharged into the secondary sedimentation tank.
[0012] Specifically, the primary sedimentation tank is connected to the coagulation tank via a pipe, the reaction tank is connected to the primary sedimentation tank via a pipe, the bottom of the primary sedimentation tank and the secondary sedimentation tank are provided with sludge discharge outlets, the secondary sedimentation tank is connected to the reaction tank via a pipe, and the secondary sedimentation tank is connected to the evaporator salt extractor via the secondary sedimentation tank outlet pipe.
[0013] Specifically, the thickening tank is set up separately, and the primary sedimentation tank and the secondary sedimentation tank are connected to the thickening tank through the mud and water discharge outlets of the primary sedimentation tank and the secondary sedimentation tank. The thickening tank is connected to the coagulation tank through the thickening tank outlet pipe.
[0014] Specifically, the evaporator is connected to the wastewater deep treatment tank through the evaporator connecting pipe, the evaporator is connected to the secondary sedimentation tank through the secondary sedimentation tank outlet pipe, the concentrated mother liquor of the evaporator is returned to the coagulation tank through the evaporator concentrated mother liquor return pipe, the distilled water is recycled and reused through the water recovery chamber, and the solid salt is stored in the solid salt collection chamber.
[0015] This utility model has the following beneficial effects:
[0016] This invention relates to a device for reducing the volume of concentrated mother liquor after evaporation and salt extraction of coking wastewater. The device mixes the evaporated mother liquor with the original liquor and then performs sedimentation separation to remove COD components. F ions are removed by chemical sedimentation. The remaining salt is converted into solid salt through evaporation, thus avoiding the accumulation of COD and corrosive ions in the system. This solves the problem of mother liquor discharge and addresses the issues of difficult coking wastewater treatment, complex composition of concentrated mother liquor after concentration, and severe foaming and corrosion caused by direct evaporation of concentrated mother liquor.
[0017] The sludge discharged from this device contains only a small amount of salt, which can significantly reduce the adverse effects on coal blending and avoid the adverse effects on coke quality caused by directly blending the mother liquor with coal. Attached Figure Description
[0018] Figure 1 This is a schematic diagram of the structure and working principle of a device for reducing the volume of concentrated mother liquor after evaporation and salt extraction of coking wastewater.
[0019] Figure 2 This is a schematic diagram of the existing coking wastewater evaporation process.
[0020] In the diagram: 1-Deep wastewater treatment tank, 1.1-Potential agent and activated carbon powder addition pipe for deep wastewater treatment tank, 1.2-Sludge discharge pipe for deep wastewater treatment tank, 1.3-Coagulation tank connection pipe, 1.4-Evaporator salt extractor connection pipe; 2-Concentrated mother liquor treatment system, 2.1-Coagulation tank, 2.2-Primary sedimentation tank, 2.3-Reaction tank, 2.4-Secondary sedimentation tank, 2.5-Concentration tank, 2.6-Coagulation tank flocculant addition pipe, 2.7-Evaporator salt extractor concentrated mother liquor return pipe, 2.8-Reaction tank calcium chloride and sodium hydroxide addition pipe, 2.9-Secondary sedimentation tank effluent pipe, 2.10-Concentration tank effluent pipe, 2.11-Primary and secondary sedimentation tank sludge and water discharge outlet; 3-Evaporator salt extractor, 3.1-Water recovery chamber, 3.2-Solid salt collection chamber; 4-Coking wastewater discharge pipe. Detailed Implementation
[0021] The technical solutions of the present utility model will be described in further detail below with reference to the accompanying drawings of the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present utility model without creative effort are within the scope of protection of the present utility model.
[0022] like Figure 1As shown, a device for reducing the volume of concentrated mother liquor after evaporation and salt extraction of coking wastewater includes a wastewater deep treatment tank 1, a concentrated mother liquor treatment system 2, and an evaporator 3. The inlet of the wastewater deep treatment tank 1 is connected to a coking wastewater discharge pipe 4. The wastewater discharged from the wastewater deep treatment tank 1 flows into the concentrated mother liquor treatment system 2 and the evaporator 3 through a pipe. The concentrated mother liquor treatment system 2 is located between the wastewater deep treatment tank 1 and the evaporator 3. The evaporator 3 is connected to the wastewater deep treatment tank 1 and the concentrated mother liquor treatment system 2 through a pipe. The evaporator 3 is equipped with a water recovery chamber 3.1 and a solid salt collection chamber 3.2.
[0023] After absorbing coking wastewater, the wastewater deep treatment tank 1 is used for preliminary wastewater treatment. After treatment, chemicals and activated carbon powder are added to the wastewater deep treatment tank 1 through the chemical and activated carbon powder addition pipe 1.1. The wastewater and sludge then enter the concentrated mother liquor treatment system 2. Most of the wastewater flows into the coagulation tank 2.1. When the coagulation tank 2.1 is saturated, a small portion of the wastewater flows into the evaporator salt extractor 3, while the sludge directly enters the reaction tank 2.3. The concentrated mother liquor treatment system 2 includes the coagulation tank... 2.1, 2.2, 2.3, 2.4, 2.5, and 2.6, a primary sedimentation tank, a secondary sedimentation tank, and a thickening tank. The concentrated mother liquor treatment system 2 is used to further treat the wastewater and sludge. In the coagulation tank 2.1, flocculant is added through the flocculant addition pipe 2.6. The coagulation tank 2.1 absorbs the wastewater discharged from the deep wastewater treatment tank 1, the wastewater separated from the thickening tank 2.5, and the concentrated mother liquor returned from the evaporator salt extractor 3. After treatment in the coagulation tank 2.1, the sludge flows into the primary sedimentation tank 2.2. The primary sedimentation tank 2.2, after initial sedimentation... After sedimentation, the wastewater is discharged into reaction tank 2.3, and the sludge is discharged into thickening tank 2.5 through the sludge discharge port. In reaction tank 2.3, calcium chloride and sodium hydroxide are added through the calcium chloride and sodium hydroxide addition pipes for further treatment. The wastewater and sludge are then discharged into secondary sedimentation tank 2.4, where they settle again. The wastewater is then discharged into evaporator 3, and the sludge is also discharged into thickening tank 2.5 through the sludge discharge port. After thickening treatment in thickening tank 2.5, a small amount of residual wastewater is separated. The wastewater is returned to the coagulation tank 2.1, and the sludge is used for coal blending after being filtered. The evaporator salt extractor 3 is used for the final treatment of wastewater by evaporation and salt extraction. After evaporation and salt extraction, the wastewater entering the evaporator salt extractor 3 yields concentrated mother liquor, distilled water and solid salt. The concentrated mother liquor is directly returned to the coagulation tank 2.1. The distilled water is stored and recycled in the water recovery bin 3.1 and reused. The solid salt is stored in the solid salt collection bin 3.2. When the collection bin is close to saturation, the solid salt is taken out and disposed of in accordance with regulations.
[0024] 1. Wastewater generated from coking enters the deep wastewater treatment tank 1 for treatment. Part of the treated effluent is sent to the inlet of the coagulation tank 2.1, and the excess is sent to the evaporator salt extractor 3 for further treatment. The coagulation tank 2.1 receives the effluent from the deep wastewater treatment tank 1, the return concentrated mother liquor, and the effluent from the thickening tank 2.5. Flocculant is added and the mixture is thoroughly mixed. The effluent from the coagulation tank 2.1 is sent to the primary sedimentation tank 2.2 for sedimentation separation. The effluent from the primary sedimentation tank 2.2 is sent to the reaction tank 2.3, and the sludge discharged from the bottom of the primary sedimentation tank 2.2 is sent to the thickening tank 2.5. The reaction tank 2.3... The effluent from the primary sedimentation tank 2.2 is mixed with the sludge discharged from the deep wastewater treatment tank 1, and calcium chloride and sodium hydroxide are added sequentially for reaction. The effluent from the reaction tank 2.3 enters the secondary sedimentation tank 2.4 for sedimentation separation. The effluent from the secondary sedimentation tank 2.4 is mixed with the effluent from the deep wastewater treatment tank 1 and then enters the evaporator salt extractor 3. The sludge discharged from the bottom of the secondary sedimentation tank 2.4 is mixed with the sludge discharged from the primary sedimentation tank 2.2 and then enters the thickening tank 2.5 for sedimentation separation. The effluent from the thickening tank 2.5 enters the coagulation tank 2.1, and the sludge discharged from the bottom of the thickening tank 2.5 is sent to the coal blending treatment.
[0025] 2. The sludge produced from the deep wastewater treatment tank 1 is sent to the reaction tank 2.3 to make full use of the residual chemicals and activated carbon in the sludge, further reduce COD and improve the efficiency of chemical use.
[0026] 3. The distilled water from the evaporator 3 is reused for production makeup water. The solid salt produced by the evaporator 3 is disposed of in accordance with regulations. The concentrated mother liquor produced by the evaporator 3 is sent to the coagulation tank 2.1 for dilution and further treatment.
[0027] 4. The ratio of the flow rate of wastewater deep treatment tank 1 entering coagulation tank 2.1 to the return flow rate of concentrated mother liquor is 1 to 3, so as to ensure that the salt concentration in the concentrated mother liquor is reduced to below the precipitation concentration.
[0028] 5. The flocculant added to the coagulation tank 2.1 is PAM or PAC.
[0029] 6. The purpose of adding calcium chloride to reaction tank 2.3 is to remove F ions from the water, so that the F ion concentration in the effluent is ≤50mg / L. The purpose of adding sodium hydroxide to reaction tank 2.3 is to adjust the pH of the effluent, so that the pH is within the range of 7-9, to avoid corrosion of the subsequent evaporation and salt extraction equipment. Quicklime (calcium hydroxide) must not be used in reaction tank 2.3 to avoid the magnesium ions mixed in from generating hydrogen chloride at high temperature after coal blending. Hydrogen chloride reacts with indene and other substances in the coal gas to generate organic chlorides, which will affect the chloride ion index of the subsequent coking crude benzene product.
[0030] This utility model is not limited to the above-described embodiments. Anyone should know that any structural changes made under the guidance of this utility model, and any technical solutions that are the same as or similar to this utility model, fall within the protection scope of this utility model.
[0031] The technologies, shapes, and structures not described in detail in this utility model are all known technologies.
[0032] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.
[0033] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.
Claims
1. A device for reducing the amount of concentrated mother liquor after evaporation and salt extraction of coking wastewater, characterized in that, The sewage deep treatment tank, the concentrated mother liquor treatment system and the evaporation salt extractor are connected with the coking wastewater discharge pipe, and the sewage discharged from the sewage deep treatment tank flows into the concentrated mother liquor treatment system and the evaporation salt extractor through the pipeline.
2. The coking wastewater evaporation salt extraction post-concentrated mother liquor reduction treatment device according to claim 1, characterized in that, The sewage deep treatment tank is directly connected with the coking wastewater discharge pipe, and the sewage deep treatment tank is provided with a water inlet, a water outlet and a sludge discharge port.
3. The device for reducing the amount of concentrated mother liquor after evaporation and salt extraction of coking wastewater according to claim 1, characterized in that, The concentrated mother liquor treatment system comprises a coagulation tank, a primary sedimentation tank, a reaction tank, a secondary sedimentation tank and a concentration tank.
4. The coking wastewater evaporation salt extraction post-concentrated mother liquor reduction treatment device according to claim 3, characterized in that, The primary sedimentation tank is connected with the coagulation tank through a pipeline, the reaction tank is connected with the primary sedimentation tank through a pipeline, the bottom of the primary sedimentation tank and the secondary sedimentation tank is provided with a sludge discharge port, the secondary sedimentation tank is connected with the reaction tank through a pipeline, and the secondary sedimentation tank is connected with the evaporation salt extractor through a secondary sedimentation tank water outlet pipeline.
5. The device for reducing the amount of concentrated mother liquor after evaporation and salt extraction of coking wastewater according to claim 3, characterized in that, The concentration tank is separately arranged, the primary sedimentation tank and the secondary sedimentation tank are connected with the concentration tank through primary sedimentation tank and secondary sedimentation tank sludge-water discharge ports, and the concentration tank is connected with the coagulation tank through a concentration tank water outlet pipeline.
6. The device for reducing the amount of concentrated mother liquor after evaporation and salt extraction of coking wastewater according to claim 1, characterized in that, The evaporation salt extractor is connected with the sewage deep treatment tank through an evaporation salt extractor connecting pipeline, the evaporation salt extractor is connected with the secondary sedimentation tank through a secondary sedimentation tank water outlet pipeline, the evaporation salt extractor is connected with the coagulation tank through an evaporation salt extractor concentrated mother liquor return pipeline, distilled water is recycled through a water recovery bin, and solid salt is stored in a solid salt collection bin.