Membrane distillation evaporative crystallization device suitable for high-salinity wastewater

Abstract

The utility model relates to a membrane distillation evaporative crystallization device suitable for high-salinity wastewater. The membrane distillation evaporative crystallization device comprises a raw water tank, a heat exchanger I, a membrane distillation reactor, a low-temperature crystallization centrifuge, a heat exchanger II, a heat exchanger III, a primary evaporative crystallizer and a secondary evaporative crystallizer which are sequentially connected through pipelines along the water flow direction, the clear water end of the heat exchanger III is in reflux connection to the clear water end of the heat exchanger I through a pipeline, the clear water end water outlet of the heat exchanger II is in reflux connection to the clear water end water inlet of the membrane distillation reactor through a cryostat and a circulating pump, and the clear water end water outlet of the membrane distillation reactor is connected to the clear water end water inlet of the heat exchanger II through a pipeline. By adopting the membrane distillation reactor, the membrane pollution condition can be effectively reduced, high-rate concentration of the high-salinity wastewater is realized, and a large amount of high-quality water is recovered for reuse; by arranging the first heat exchanger and the third heat exchanger, steam heat energy generated by the primary evaporation crystallizer and the secondary evaporation crystallizer can be effectively recycled, and the heat energy utilization efficiency is improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of high salt wastewater treatment especially relates to a membrane distillation evaporation crystallization device suitable for high salt wastewater. BACKGROUND

[0002] High salt wastewater refers to wastewater with a total salt content of at least 3.5wt%, and contains various substances including salt, oil, organic heavy metals and radioactive substances. China's coal chemical industry, petroleum chemical industry, steel and metallurgy and other fields will produce a large amount of high salt wastewater every year, which will cause serious damage to the ecological environment if not properly treated. At the same time, with the increasingly strict requirements of national environmental protection, chemical industry parks even require wastewater "zero" discharge, so the demand for economically feasible high salt wastewater treatment technology is very urgent.

[0003] The salt content of high salt wastewater is complex, and the high salt wastewater in chemical industry parks mainly contains Na+, SO42-, Cl-, and also contains a small amount of K+, Ca2+, Mg2+, Fe3+ and other salt ions. The industry mainly uses nanofiltration / reverse osmosis for membrane concentration and reduction treatment and evaporation crystallization treatment. However, there is serious membrane pollution during the operation of nanofiltration / reverse osmosis membrane, and the operation cost is high. The evaporation crystallization process has low heat energy utilization efficiency and high energy consumption in the treatment process, and also has problems such as non-standard salt purity of crystallization products, inability to realize resource utilization, and large amount of production of impure salt. UTILITY MODEL CONTENT

[0004] Therefore, it is necessary to provide a membrane distillation evaporation crystallization device suitable for high salt wastewater to solve the problem of large operation energy consumption of the existing high salt treatment system.

[0005] To achieve the above purpose, the inventors provide a membrane distillation evaporation crystallization device suitable for high salt wastewater, which comprises a raw water tank, a heat exchanger one, a membrane distillation reactor, a low-temperature crystallization centrifuge, a heat exchanger two, a heat exchanger three, a primary evaporation crystallizer and a secondary evaporation crystallizer connected by pipelines in sequence along the water flow direction; a flat plate membrane is horizontally arranged in the membrane distillation reactor, which divides the membrane distillation reactor into a membrane distillation reactor clean water end and a membrane distillation reactor sewage end above; the raw water tank is connected with a high salt wastewater source, the raw water tank is connected with the sewage end of the heat exchanger one through a water inlet pump, the sewage end of the heat exchanger one is connected with the sewage end of the membrane distillation reactor through a pipeline, the sewage end of the membrane distillation reactor is connected with the low-temperature crystallization centrifuge through a pipeline, the low-temperature crystallization centrifuge is connected with the sewage end of the heat exchanger two through a lifting pump, the sewage end of the heat exchanger two is connected with the sewage end of the heat exchanger three, and the sewage end of the heat exchanger three is connected with the primary evaporation crystallizer through a pipeline.

[0006] The clean water end of the heat exchanger three is connected to the clean water end of the heat exchanger one through a pipeline, the clean water end outlet of the heat exchanger two is connected to the clean water end inlet of the membrane distillation reactor through a low-temperature thermostat and a circulating pump, and the clean water end outlet of the membrane distillation reactor is connected to the clean water end inlet of the heat exchanger two through a pipeline.

[0007] Further, the flat plate membrane is selected to be a super-hydrophobic membrane.

[0008] Further, an electric proportional valve two is arranged on the connecting pipeline between the sewage end of the membrane distillation reactor and the low-temperature crystallization centrifuge.

[0009] Further, a bypass pipeline one is arranged on the connecting pipeline between the sewage end of the membrane distillation reactor and the low-temperature crystallization centrifuge, and the bypass pipeline is connected to the raw water tank, and an electric proportional valve one is arranged on the bypass pipeline.

[0010] Further, an electric proportional valve four is arranged on the connecting pipeline between the clean water end outlet of the membrane distillation reactor and the clean water end inlet of the heat exchanger two.

[0011] Further, a reuse water collection tank one is arranged on the connecting pipeline between the clean water end outlet of the membrane distillation reactor and the clean water end inlet of the heat exchanger two through a bypass pipeline two, and an electric proportional valve three is arranged on the bypass pipeline two.

[0012] Further, an electric proportional valve six is arranged on the connecting pipeline between the sewage end of the heat exchanger two and the sewage end of the heat exchanger three.

[0013] Further, a bypass pipeline three is arranged on the connecting pipeline between the sewage end of the heat exchanger two and the sewage end of the heat exchanger three, and the bypass pipeline three is connected to the raw water tank, and an electric proportional valve five is arranged on the bypass pipeline three.

[0014] Further, the primary evaporation crystallizer and the secondary evaporation crystallizer are connected to the clean water end of the heat exchanger three through a steam vacuum pump, and an electric proportional valve seven and an electric proportional valve eight are arranged on the pipeline connecting the primary evaporation crystallizer and the secondary evaporation crystallizer to the steam vacuum pump, respectively.

[0015] Further, the clean water end of the heat exchanger one is connected to a reuse water collection tank two.

[0016] Compared with the prior art, the technical scheme has the following advantages: the membrane distillation reactor can effectively reduce membrane pollution, realize high-salinity wastewater high-ratio concentration, and recover a large amount of high-quality water for reuse; the phase equilibrium diagram of sodium sulfate-sodium chloride-water is used to realize selective crystallization of high-quality sodium sulfate product salt in the low-temperature crystallization centrifuge from the membrane concentrated liquid; the heat exchanger one and the heat exchanger three are arranged to effectively recover steam heat energy generated by the primary evaporation crystallizer and the secondary evaporation crystallizer, and improve heat energy utilization efficiency; the heat exchanger two is arranged to reduce the water temperature of the membrane distillation reactor clean water end (cold side), achieve the goal of reducing the energy consumption of the low-temperature thermostat, and also preheat the feed of the primary evaporation crystallizer to save energy. Finally, high-quality sodium chloride product salt is precipitated from the primary evaporation crystallizer, effectively reducing the amount of final salt produced by the system and effectively reducing the salt content of the wastewater. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 A membrane distillation evaporation crystallization device suitable for high-salinity wastewater.

[0018] BRIEF DESCRIPTION OF DRAWINGS:

[0019] 1-raw water tank; 2-water inlet pump; 3-heat exchanger one; 4-membrane distillation reactor; 401-membrane distillation reactor clean water end; 402-membrane distillation reactor sewage end; 403-flat membrane; 5-electric proportional valve one; 6-electric proportional valve two; 7-low-temperature crystallization centrifuge; 8-lift pump; 9-heat exchanger two; 902-heat exchanger two sewage end; 10-low-temperature thermostat; 11-circulating pump; 121-reuse water collection tank one; 122-reuse water collection tank two; 1201-electric proportional valve three; 1202-electric proportional valve four; 13-electric proportional valve five; 14-electric proportional valve six; 15-heat exchanger three; 1502-heat exchanger three sewage end; 16-primary evaporation crystallizer; 17-secondary evaporation crystallizer; 18-steam vacuum pump; 19-electric proportional valve seven; 20-electric proportional valve eight. DETAILED DESCRIPTION

[0020] In order to explain the possible application scenarios, technical principles, specific schemes that can be implemented, purposes and effects that can be achieved, etc. of the present application in detail, the following will be described in detail in combination with the specific embodiments listed and with the aid of the drawings. The embodiments described in this paper are only used to more clearly illustrate the technical scheme of the present application, and therefore only serve as examples, and cannot limit the protection scope of the present application.

[0021] The term "embodiment" is mentioned herein means that the specific features, structures, or characteristics described in connection with the embodiment can be included in at least one embodiment of the present application. The term "embodiment" appearing in various places in the specification does not necessarily refer to the same embodiment, nor does it particularly limit the independence or association between other embodiments. In principle, in the present application, as long as there is no technical contradiction or conflict, each technical feature mentioned in each embodiment can be combined in any way to form a corresponding implementable technical solution.

[0022] Unless otherwise defined, the meanings of the technical terms used herein are the same as those commonly understood by those skilled in the art to which the present application belongs; the use of related terms herein is only for the purpose of describing specific embodiments, and is not intended to limit the present application.

[0023] In the description of the present application, the phrase "and / or" is a description of the logical relationship between the objects, which means that there can be three relationships, for example, A and / or B, which means that there are three cases: A exists, B exists, and A and B exist at the same time. In addition, the character " / " herein generally represents that the associated objects before and after are a "or" logical relationship.

[0024] In the present application, terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual quantity, primary and secondary, or order relationship between the entities or operations.

[0025] Without more limitations, in the present application, the phrases "include", "contain", "have" or other similar open expressions used in the statement are intended to cover non-exclusive inclusion, and these expressions do not exclude the presence of other elements in the process, method or product including the described elements, so that the process, method or product including a series of elements can not only include those limited elements, but also include other elements not explicitly listed, or also include elements inherent to such process, method or product.

[0026] As the same as the understanding in the "Guidelines for Examination", in the present application, the expressions "greater than", "less than", "exceed" and the like are understood as not including the number; the expressions "above", "below", "within" and the like are understood as including the number. In addition, in the description of the embodiments of the present application, the meaning of "multiple" is more than two (including two), and similar expressions related to "multiple" are also understood in this way, for example, "multiple groups", "multiple times" and the like, unless otherwise explicitly limited.

[0027] In the description of the embodiments of the present application, the spatial relative expressions, such as "central", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "vertical", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", and the like, indicate the orientation or positional relationship based on the orientation or positional relationship shown in the specific embodiments or the drawings, and are only for the convenience of describing the specific embodiments of the present application or for the convenience of the reader to understand, and do not indicate or imply that the indicated device or component must have a particular position, a particular orientation, or be constructed or operated in a particular orientation, and therefore cannot be understood as a limitation on the embodiments of the present application.

[0028] Unless otherwise explicitly specified or limited, in the description of the embodiments of the present application, the terms "mount", "connect", "connect", "fix", "set", and the like should be understood in a broad sense. For example, the "connection" can be fixed connection, or detachable connection, or integral setting; it can be direct connection, or indirect connection through intermediate medium; it can be the relationship of two components combined together, or the relationship of interaction of two components, or the internal communication of two structures. For those skilled in the art to which the present application belongs, the specific meaning of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0029] Please refer to Figure 1 The embodiment of the present application is a kind of membrane distillation evaporation crystallization device suitable for high salt wastewater, including raw water tank 1, heat exchanger one 3, membrane distillation reactor 4, low temperature crystallization centrifuge 7, heat exchanger two 9, heat exchanger three 15, primary evaporation crystallizer 16 and secondary evaporation crystallizer 17 connected by pipeline in turn along water flow direction;Flat plate membrane 403 is arranged transversely in the membrane distillation reactor, the flat plate membrane 403 separates the membrane distillation reactor into the membrane distillation reactor clean water end 401 above and the membrane distillation reactor sewage end 402, the raw water tank 1 is connected with the sewage end of the heat exchanger one 3 by water inlet pump 2, the sewage end of the heat exchanger one 3 is connected with the membrane distillation reactor sewage end 402 by pipeline, the membrane distillation reactor sewage end 402 is connected with low temperature crystallization centrifuge 7 by pipeline, the low temperature crystallization centrifuge 7 is connected with the sewage end of heat exchanger two 9 by lifting pump 8, the sewage end of heat exchanger two 9 is connected with the sewage end of heat exchanger three 15, the sewage end of heat exchanger three 15 is connected with primary evaporation crystallizer 16 by pipeline;

[0030] The clean water end of the heat exchanger three 15 is connected to the clean water end of the heat exchanger one 3 through a pipeline, the clean water end outlet of the heat exchanger two 9 is connected to the clean water end 401 inlet of the membrane distillation reactor through a low-temperature thermostat 10 and a circulating pump 11, and the clean water end 401 outlet of the membrane distillation reactor is connected to the clean water end inlet of the heat exchanger two 9 through a pipeline.

[0031] The bottom of the low-temperature crystallization centrifuge 7, the primary evaporation crystallizer 16 and the secondary evaporation crystallizer 17 is respectively provided with a sodium sulfate crystallization discharge pipe, a sodium chloride crystallization discharge pipe and a miscellaneous salt discharge pipe for discharging the crystallization produced in the equipment.

[0032] In some embodiments, the flat sheet membrane 403 is selected to be a super-hydrophobic membrane. Its beneficial effect is to improve the membrane flux and effectively reduce the membrane pollution.

[0033] In some embodiments, an electric proportional valve two 6 is arranged on the connecting pipeline between the membrane distillation reactor dirty water end 402 and the low-temperature crystallization centrifuge 7.

[0034] In some embodiments, a bypass pipeline one is further arranged on the connecting pipeline between the membrane distillation reactor dirty water end 402 and the low-temperature crystallization centrifuge 7 to return to the raw water tank 1, and an electric proportional valve one 5 is arranged on the bypass pipeline. The membrane concentration multiple of the membrane distillation reactor can be adjusted by adjusting the electric proportional valve one 5 and the electric proportional valve two 6, so that the sodium sulfate in the membrane concentrated solution reaches a saturated or supersaturated state.

[0035] In some embodiments, an electric proportional valve four 1202 is arranged on the connecting pipeline between the membrane distillation reactor clean water end 401 outlet and the clean water end inlet of the heat exchanger two 9.

[0036] In some embodiments, a reuse water collection tank one 121 connected through a bypass pipeline two is arranged on the connecting pipeline between the membrane distillation reactor clean water end 401 outlet and the clean water end inlet of the heat exchanger two 9, and an electric proportional valve three 1201 is arranged on the bypass pipeline two. The clean water end inlet of the heat exchanger two 9 can be controlled by adjusting the electric proportional valve three 1201 and the electric proportional valve four 1202.

[0037] In some embodiments, an electric proportional valve six 14 is arranged on the connecting pipeline between the heat exchanger two dirty water end 902 and the heat exchanger three dirty water end 1502.

[0038] In some embodiments, a bypass pipe three is further provided on the connecting pipe between the sewage end 902 of the heat exchanger two and the sewage end 1502 of the heat exchanger three, and the bypass pipe three is connected to the raw water tank 1, and an electric proportional valve five 13 is provided on the bypass pipe three. The concentration of sodium chloride in the membrane concentrate can be further adjusted by adjusting the electric proportional valve five 13 and the electric proportional valve six 14.

[0039] In some embodiments, the primary evaporative crystallizer 16 and the secondary evaporative crystallizer are both connected to the clean water end of the heat exchanger three 15 through a steam vacuum pump 18, and an electric proportional valve seven 19 and an electric proportional valve eight 20 are respectively provided on the pipes connecting the primary evaporative crystallizer 16 and the secondary evaporative crystallizer to the steam vacuum pump 18. The speed of the steam entering the heat exchanger three 15 from the primary evaporative crystallizer 16 and the secondary evaporative crystallizer can be controlled by adjusting the electric proportional valve seven 19 and the electric proportional valve eight 20.

[0040] In some embodiments, the clean water end of the heat exchanger one 3 is connected to a reclaimed water collection tank two 122. The reclaimed water from the clean water end of the heat exchanger one 3 can be collected in the reclaimed water collection tank two 122.

[0041] The utility model discloses a membrane distillation reaction tank, a low temperature thermostat, a low temperature crystallizer, a low temperature crystallization centrifugal machine, a first evaporation crystallizer and a second evaporation crystallizer are arranged in the high salt wastewater treatment system, and the system is connected through the heat exchanger.

[0042] Finally, it should be noted that, although the above embodiments have been described in the specification and drawings of the present application, but can not therefore limit the patent protection scope of the present application. Any equivalent structure or equivalent flow replacement or modification based on the essential concept of the present application, using the content of the present application specification and drawing, the technical solutions produced, and directly or indirectly, the technical solutions of the above embodiments are implemented in other related technical fields, etc., are included in the patent protection scope of the present application.

Claims

1. A membrane distillation evaporative crystallization apparatus suitable for high salinity wastewater, characterized in that, The application relates to a high-salinity wastewater treatment device, which comprises a raw water tank, a heat exchanger I, a membrane distillation reactor, a low-temperature crystallization centrifuge, a heat exchanger II, a heat exchanger III, a primary evaporation crystallizer and a secondary evaporation crystallizer which are connected in sequence along the water flow direction; a flat plate membrane is arranged in the membrane distillation reactor, the flat plate membrane separates the membrane distillation reactor into a membrane distillation reactor clean water end and a membrane distillation reactor sewage end, the raw water tank is connected with a high-salinity wastewater source, the raw water tank is connected with the sewage end of the heat exchanger I through a water inlet pump, the sewage end of the heat exchanger I is connected with the sewage end of the membrane distillation reactor through a pipeline, the sewage end of the membrane distillation reactor is connected with the low-temperature crystallization centrifuge through a pipeline, the low-temperature crystallization centrifuge is connected with the sewage end of the heat exchanger II through a lifting pump, the sewage end of the heat exchanger II is connected with the sewage end of the heat exchanger III, and the sewage end of the heat exchanger III is connected with the primary evaporation crystallizer through a pipeline. The clean water end of the heat exchanger III is connected with the clean water end of the heat exchanger I through a pipeline, the clean water end outlet of the heat exchanger II is connected with the clean water end inlet of the membrane distillation reactor through a low-temperature thermostat and a circulating pump, and the clean water end outlet of the membrane distillation reactor is connected with the clean water end inlet of the heat exchanger II through a pipeline.

2. The membrane distillation evaporative crystallization device suitable for high salinity wastewater according to claim 1, characterized in that: The flat plate membrane is an ultrahydrophobic membrane.

3. The membrane distillation evaporative crystallization device suitable for high salinity wastewater of claim 1, wherein: An electric proportional valve II is arranged on the connecting pipeline between the sewage end of the membrane distillation reactor and the low-temperature crystallization centrifuge.

4. The membrane distillation evaporative crystallization apparatus suitable for high salinity wastewater according to claim 1 or 3, characterized in that: A bypass pipeline I is further arranged on the connecting pipeline between the sewage end of the membrane distillation reactor and the low-temperature crystallization centrifuge to return to the raw water tank, and an electric proportional valve I is arranged on the bypass pipeline.

5. The membrane distillation evaporative crystallization device suitable for high salinity wastewater of claim 1, wherein: An electric proportional valve IV is arranged on the connecting pipeline between the clean water end outlet of the membrane distillation reactor and the clean water end inlet of the heat exchanger II.

6. The membrane distillation evaporative crystallization apparatus suitable for high salinity wastewater of claim 1 or 5, characterized in that: A reused water collecting tank I is arranged on the connecting pipeline between the clean water end outlet of the membrane distillation reactor and the clean water end inlet of the heat exchanger II through a bypass pipeline II, and an electric proportional valve III is arranged on the bypass pipeline II.

7. The membrane distillation evaporative crystallization device suitable for high salinity wastewater of claim 1, wherein: An electric proportional valve VI is arranged on the connecting pipeline between the sewage end of the heat exchanger II and the sewage end of the heat exchanger III.

8. The membrane distillation evaporative crystallization apparatus suitable for high salinity wastewater of claim 1 or 7, characterized in that: A bypass pipeline III is further arranged on the connecting pipeline between the sewage end of the heat exchanger II and the sewage end of the heat exchanger III to return to the raw water tank, and an electric proportional valve V is arranged on the bypass pipeline III.

9. The membrane distillation evaporative crystallization device suitable for high salinity wastewater of claim 1, wherein: The primary evaporation crystallizer and the secondary evaporation crystallizer are connected with the clean water end of the heat exchanger III through steam vacuum pumps, and an electric proportional valve VII and an electric proportional valve VIII are arranged on the pipelines connecting the primary evaporation crystallizer and the secondary evaporation crystallizer with the steam vacuum pump respectively.

10. The membrane distillation evaporative crystallization device suitable for high salinity wastewater of claim 1, wherein: The clean water end of the heat exchanger I is connected with a reused water collecting tank II.

Images