Multi-stage treatment system for high-salinity wastewater

Abstract

The utility model discloses a multi-stage treatment system for high-salinity wastewater, which comprises a water sample detection and analysis system for sampling and analyzing the high-salinity wastewater in at least three batches to obtain the pH value, COD (Chemical Oxygen Demand), TDS (Total Dissolved Solids), hardness and the numerical value range of each pollutant content of the wastewater; the ozonization system is used for fully contacting the detected and analyzed high-salinity wastewater with ozone to obtain ozonized effluent; the pretreatment system is used for settling and filtering the ozonized effluent to obtain pretreated effluent and a pretreated concentrated solution; the electrolytic hydrogen production system is used for carrying out in-situ electrolysis on the pretreated effluent to obtain hydrogen, oxygen and a wastewater concentrated solution; the membrane distillation system is used for carrying out membrane distillation treatment on the wastewater concentrated solution to obtain pure water and a membrane distillation concentrated solution; the evaporation system is used for carrying out evaporation treatment on the pretreatment concentrated solution and the membrane distillation concentrated solution to obtain solid waste. According to the utility model, the wastewater utilization rate is greater than 80%, the hydrogen purity is greater than 99.9%, and the TDS of membrane distillation pure water is less than 50mg / L.

Description

TECHNICAL FIELD

[0001] The utility model belongs to wastewater treatment technical field, especially relate to a high salt wastewater multistage treatment system. BACKGROUND

[0002] The coal-fired power plant unit will produce a large amount of sulfide-containing flue gas in operation, needs to carry out desulfurization treatment, and about 90% of the current coal-fired power plant is equipped with wet flue gas desulfurization technology, which will produce a large amount of desulfurization wastewater. Desulfurization wastewater as a typical industrial high-salinity wastewater, its suspended solids, salt content, hardness and other contents are high, heavy metals, COD and other indicators exceed the standard, among which the strong corrosion of a large amount of chloride ions makes the wastewater treatment more difficult, so it becomes one of the end wastewater of the power plant which is difficult to treat.

[0003] At present, the treatment means for desulfurization wastewater mainly concentrates on chemical coagulation sedimentation treatment (three-link box process) and zero-emission treatment process (evaporation crystallization, etc.), and there is no direct electrolysis of desulfurization wastewater to produce hydrogen. The research is related to this, which is determined by the complex components contained in the desulfurization wastewater. The mainstream electrolytic water hydrogen production technology (ALK, PEM) of industrialization has very high requirements for water quality, and the water is pure water, almost without any impurity ion. The suspended solids concentration of desulfurization wastewater is extremely high, the hardness is extremely high (10000-30000mg / L, the main component is Ca 2+ and Mg 2+ ), usually also contains F - exceeding the emission standard, TDS concentration can reach 10000-50000mg / L (main components are Na + , Cl - and SO4 2- ), and may also contain Hg, Cr, Ni and other heavy metal elements, so it does not have the conditions for direct electrolysis of hydrogen by ALK or PEM technology.

[0004] In recent years, with the emergence and implementation of a series of environmental protection regulations and policies, it has become an inevitable choice to improve water efficiency and realize effective reuse of wastewater. The high-salinity wastewater concentration treatment technology with application cases mainly includes heat method and membrane method.

[0005] The Chinese patent application No. CN202110218211.2 discloses a desulfurization wastewater heat method and membrane method coupled concentration system and method, and belongs to the technical field of desulfurization wastewater treatment. The system comprises a wastewater pretreatment system, a draft fan, an evaporation tower, a circulating water pump and a membrane distillation device. Flue gas after a dust collector is used as a heat source to directly exchange heat with desulfurization wastewater in the evaporation tower. Through evaporation of the wastewater, concentration and reduction of the wastewater are realized. Meanwhile, a membrane distillation device is added to a circulating loop of the desulfurization wastewater. The waste heat after evaporation of the wastewater is used to realize recovery of high-quality condensed water. The membrane distillation cooling medium is low-temperature air. The air enters an air preheater after recovering part of heat through the membrane distillation system. The application realizes concentration and reduction of the wastewater through the membrane method and the heat method coupled system. However, the above-mentioned treatment method system is complex, the initial investment is large, and the operation and maintenance requirements are high due to the poor water quality condition of the high-salinity wastewater, and the economic benefit is poor. Therefore, it is of great significance to develop a high-salinity wastewater treatment system with high economic efficiency. Practical new type content

[0006] The utility model provides a high salt wastewater multistage treatment system, can improve water resource utilization rate greatly.

[0007] To solve the above technical problem, the utility model provides a high salt wastewater multistage treatment system, including:

[0008] Water sample detection and analysis system: it carries out sampling analysis to high salt wastewater in at least three batches, obtains wastewater pH, COD, TDS, hardness and various pollutant content numerical range, water sample detection and analysis system are connected with ozonation system through pipeline,

[0009] Ozonation system: it fully contacts the high salt wastewater after detection and analysis with ozone, obtains ozonation effluent, and the ozonation system is connected with the pretreatment system through the pipeline,

[0010] Pretreatment system: it carries out settlement and filtration to the ozonation effluent, obtains pretreatment effluent and pretreatment concentrated solution, and the pretreatment system is also connected with electrolytic hydrogen production system and evaporation system through the pipeline respectively, and the pretreatment effluent enters the electrolytic hydrogen production system of next stage, and the pretreatment concentrated solution enters the evaporation system,

[0011] Electrolytic hydrogen production system: it includes water collecting component and electrolysis component, and the water collecting component and electrolysis component are connected through the pipeline, the water collecting component carries out filtration to the pretreatment effluent and obtains wastewater concentrated solution and dilute electrolyte, and the water collecting component is connected with membrane distillation system through the pipeline, and the wastewater concentrated solution enters the membrane distillation system of next stage, and the electrolysis component carries out in-situ electrolysis to dilute electrolyte and obtains concentrated electrolyte, hydrogen and oxygen, and the concentrated electrolyte returns to the water collecting component and carries out filtration with the pretreatment effluent,

[0012] The membrane distillation system is connected with the evaporation system through a pipeline, and the membrane distillation concentrate enters the evaporation system.

[0013] The evaporation system is used for evaporating the pretreatment concentrate and the membrane distillation concentrate, and solid waste is obtained.

[0014] Further, the ozone generation system is provided with an ozone generator connected with the electrolytic hydrogen production system through a pipeline, and the ozone generator utilizes oxygen collected by the electrolytic hydrogen production system to produce ozone mixed gas.

[0015] Further, in the electrolytic hydrogen production system, the water collecting assembly is a pipe bundle type water collecting assembly.

[0016] Further, the evaporation system is provided with a flue gas evaporation device, and the driving force of the flue gas evaporation device is flue gas waste heat.

[0017] Compared with the prior art, the high-salinity wastewater multi-stage treatment system has the following technical effects: the direct electrolytic hydrogen production system and the membrane distillation pure water production system are coupled to be used for treating high-salinity wastewater, the direct electrolytic hydrogen production system extracts water in pretreated effluent by using high-concentration electrolyte, and is used for electrolysis to produce hydrogen; the system does not need to complicate purification of the water, and after the high-salinity wastewater is subjected to ozone oxidation, gravity sedimentation and filtration to remove most insoluble solids and reduce COD value, the wastewater can enter the direct electrolytic hydrogen production system for use; because the in-situ electrolytic hydrogen production system and the membrane distillation pure water production system have low requirements on water quality of the water, wastewater concentrate produced by the in-situ electrolytic hydrogen production system can directly enter the membrane distillation system for deep concentration, pure water TDS is less than 50 mg / L, hardness is close to 0, and the pure water level can be reached, and the system can utilize low-grade waste heat of a power plant, such as flue gas waste heat and boiler outlet water waste heat, as system energy consumption. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 is a schematic diagram of the high-salinity wastewater multi-stage treatment system. DETAILED DESCRIPTION

[0019] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Figure 1 The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings.

[0020] It should be understood that the step numbers used herein are only for the convenience of description, and are not limited to the execution sequence of the steps.

[0021] It should be understood that the terms used in the utility model specification are only for the purpose of describing specific embodiments and are not intended to limit the utility model. As used in the utility model specification and the appended claims, unless otherwise clear from the context, the singular forms "a", "an" and "the" are intended to include the plural forms.

[0022] The terms "comprise" and "include" indicate the presence of described features, whole, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, whole, steps, operations, elements, components and / or sets thereof.

[0023] The term "and / or" means any combination of one or more of the associated listed items and all possible combinations, and includes these combinations.

[0024] Embodiment 1

[0025] The utility model provides a kind of high-salinity wastewater multistage treatment system, as shown in Figure 1 It includes:

[0026] Water sample detection and analysis system: it carries out sampling analysis to high-salinity wastewater for at least three batches, obtains wastewater pH, COD, TDS, hardness and the numerical range of each pollutant content;The water sample detection and analysis system is connected with ozonation system by pipeline;

[0027] Ozonation system: it is fully contacted with the high-salinity wastewater after detection and analysis and ozone, obtains ozonation effluent;The ozonation system is connected with pretreatment system by pipeline;

[0028] Pretreatment system: it carries out settlement, filtration to the ozonation effluent, obtains pretreatment effluent and pretreatment concentrate, the pretreatment system is also connected with electrolytic hydrogen production system, evaporation system by pipeline respectively;The pretreatment effluent enters next stage electrolytic hydrogen production system, and the pretreatment concentrate enters evaporation system;

[0029] Electrolytic hydrogen production system: it includes water collecting component and electrolysis component, and the water collecting component and electrolysis component are connected by pipeline, and water collecting component carries out filtration to the pretreatment effluent and obtains wastewater concentrate and dilute electrolyte, and the water collecting component is connected with membrane distillation system by pipeline, and the wastewater concentrate enters next stage membrane distillation system;The electrolysis component carries out in-situ electrolysis to dilute electrolyte and obtains concentrated electrolyte, hydrogen and oxygen, and the concentrated electrolyte returns water collecting component and carries out filtration with pretreatment effluent;

[0030] membrane distillation system: which carries out membrane distillation treatment on the wastewater concentrate to obtain pure water and membrane distillation concentrate, and is connected with the evaporation system through a pipeline, and the membrane distillation concentrate enters the evaporation system;

[0031] evaporation system: which carries out evaporation treatment on the pretreated concentrate and the membrane distillation concentrate to obtain solid waste.

[0032] In a specific embodiment, the ozone oxidation system is provided with an ozone generator, which is connected with the electrolytic hydrogen production system through a pipeline, and the ozone generator utilizes the oxygen collected by the electrolytic hydrogen production system to produce ozone mixed gas.

[0033] In a specific embodiment, the electrolytic hydrogen production system is provided with a pipe bundle type water collecting assembly.

[0034] In a specific embodiment, the evaporation system is provided with a flue gas evaporation device, and the driving force of the flue gas evaporation device is flue gas waste heat.

[0035] In a specific embodiment, a high-value utilization method of high-salinity wastewater is provided, which comprises the following steps:

[0036] Water sample detection and analysis: sampling and analyzing at least three batches of high-salinity wastewater in the actual production process to obtain the numerical range of wastewater pH, COD, TDS, hardness and the content of various pollutants;

[0037] Ozone oxidation treatment: fully contacting the high-salinity wastewater after detection and analysis with ozone to obtain ozone oxidation effluent;

[0038] Wastewater pretreatment: settling and filtering the ozone oxidation effluent to obtain pretreated effluent and pretreated concentrate;

[0039] Electrolytic hydrogen production: filtering and in-situ electrolysis of the pretreated effluent through a pipe bundle type water collecting assembly to obtain hydrogen, oxygen and wastewater concentrate;

[0040] Membrane distillation treatment: carrying out membrane distillation treatment on the wastewater concentrate to obtain pure water and membrane distillation concentrate;

[0041] Evaporation treatment: utilizing low-grade waste heat of a power plant to carry out evaporation treatment on the pretreated concentrate and the membrane distillation concentrate to remove water to obtain solid waste.

[0042] In this embodiment, the boiler water waste heat can also be used as the driving force for membrane distillation treatment and evaporation treatment.

[0043] In the embodiment, the high-salt wastewater first enters the water sample detection and analysis system, and after sampling and analysis by the water sample detection and analysis system, the high-salt wastewater after detection and analysis is conveyed to the ozonation system through a pipeline and fully contacts with ozone in the ozonation system to obtain ozonation effluent; wherein, an ozone generator is arranged in the ozonation system, and the ozone is generated by the ozone generator; the ozonation effluent is further conveyed to the pretreatment system through a pipeline, and after sedimentation and filtration by the pretreatment system, pretreatment effluent and pretreatment concentrate are obtained, wherein the pretreatment effluent is conveyed to the direct electrolysis hydrogen production system through a pipeline, and the pretreatment concentrate is conveyed to the evaporation system through a pipeline; the pretreatment effluent passes through the water collecting assembly in the direct electrolysis hydrogen production system to obtain wastewater concentrate and dilute electrolyte, the wastewater concentrate is conveyed to the membrane distillation system through a pipeline, and the dilute electrolyte is in-situ electrolyzed by the electrolysis assembly in the electrolysis hydrogen production system to obtain concentrated electrolyte, hydrogen and oxygen, the concentrated electrolyte is conveyed to the water collecting assembly in the direct electrolysis hydrogen production system for regeneration through a pipeline, and the oxygen is conveyed to the ozone generator in the ozonation system through a pipeline for utilization and preparation of ozone mixed gas; the membrane distillation system performs membrane distillation treatment on the wastewater concentrate to obtain pure water and membrane distillation concentrate, and the membrane distillation concentrate is conveyed to the evaporation system through a pipeline; after the pretreatment concentrate and the membrane distillation concentrate are evaporated by the evaporation system, solid waste is obtained, and the whole process of treating the high-salt wastewater is completed.

[0044] The direct electrolysis hydrogen production system and the membrane distillation pure water production system are coupled to treat high-salt wastewater, the direct electrolysis hydrogen production system extracts water in pretreatment effluent by using high-concentration electrolyte for electrolysis to produce hydrogen, the system does not need to perform complicated purification on the water, and after the high-salt wastewater is subjected to ozonation, gravity sedimentation and filtration to remove most insoluble solids and reduce the COD value, the high-salt wastewater can be used in the direct electrolysis hydrogen production system; because the in-situ electrolysis hydrogen production system and the membrane distillation pure water production system have low requirements on the water quality of the water, the wastewater concentrate produced by the in-situ electrolysis hydrogen production system can be directly fed into the membrane distillation system for deep concentration, the pure water produced has a TDS less than 50 mg / L and a hardness close to 0, can reach the level of pure water, and the system can utilize low-grade waste heat of a power plant, such as flue gas waste heat and boiler outlet water waste heat, as energy consumption of the system.

[0045] In the embodiments of the present application, "at least one" refers to one or more, and "multiple" refers to two or more. The "and / or" describes the association relationship of the associated objects, which means that there can be three kinds of relationships, for example, A and / or B can represent the existence of A alone, the existence of A and B at the same time, and the existence of B alone. Wherein A, B can be singular or plural. The character " / " generally represents that the associated objects before and after it are in an "or" relationship. "At least one of the following" and the like means any combination of these items, including any combination of single or multiple items. For example, at least one of a, b and c can represent: a, b, c, a and b, a and c, b and c, or a and b and c, where a, b, c can be single or multiple.

[0046] The above only describes the embodiments of the present application, and does not limit the patent range of the present application. Any equivalent structure or equivalent process transformation obtained by using the content of the present application specification and drawings, or direct or indirect application in other related technical fields, is also included in the patent protection range of the present application.

Claims

1. A multi-stage treatment system for high-salinity wastewater, characterized in that, include: Water sample testing and analysis system: It performs sampling and analysis on at least three batches of high-salinity wastewater to obtain the pH, COD, TDS, hardness, and the numerical range of various pollutants in the wastewater; the water sample testing and analysis system is connected to the ozonation system through pipelines; Ozone oxidation system: It fully contacts the high-salinity wastewater that has been tested and analyzed with ozone to obtain ozonated effluent; the ozonation system is connected to the pretreatment system through pipelines; Pretreatment system: It settles and filters the ozonation effluent to obtain pretreated effluent and pretreated concentrate. The pretreatment system is also connected to the electrolytic hydrogen production system and the evaporation system through pipelines. The pretreated effluent enters the next stage of the electrolytic hydrogen production system, and the pretreated concentrate enters the evaporation system. Electrolytic hydrogen production system: It includes a water collection component and an electrolysis component, which are connected by pipelines. The water collection component filters the pretreated effluent to obtain a wastewater concentrate and a dilute electrolyte. The water collection component is connected to a membrane distillation system through pipelines, and the wastewater concentrate enters the next stage membrane distillation system. The electrolysis component performs in-situ electrolysis of the dilute electrolyte to obtain a concentrated electrolyte, hydrogen, and oxygen. The concentrated electrolyte is returned to the water collection component for filtration together with the pretreated effluent. Membrane distillation system: It performs membrane distillation treatment on the wastewater concentrate to obtain pure water and membrane distillation concentrate. The membrane distillation system is connected to the evaporation system through a pipeline, and the membrane distillation concentrate enters the evaporation system. Evaporation system: It evaporates the pretreated concentrate and the membrane distillation concentrate to obtain solid waste.

2. The multi-stage treatment system for high-salinity wastewater according to claim 1, characterized in that, The ozonation system is equipped with an ozone generator, which is connected to the electrolytic hydrogen production system via a pipeline. The ozone generator utilizes the oxygen collected by the electrolytic hydrogen production system to produce an ozone mixture.

3. The multi-stage treatment system for high-salinity wastewater according to claim 1, characterized in that, In the electrolytic hydrogen production system, the water collection assembly is a tubular water collection assembly.

4. The multi-stage treatment system for high-salinity wastewater according to claim 1, characterized in that, The evaporation system is equipped with a flue gas evaporation device, which is driven by the waste heat of the flue gas.

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