A melt crystallization system for producing fresh water

Abstract

The utility model relates to sea water desalination technical field discloses a kind of for preparing fresh water's melting crystallization system, including crystallization unit and distillation unit, crystallization unit includes raw material tank, plate crystallizer, product tank, mother liquor tank;Distillation unit includes flash tank, condenser and mother liquor concentrate storage tank, and flash tank is communicated with mother liquor tank.This technical scheme melting crystallization system is through the dual innovation of'system integration+structure optimization', both solves the core problem that traditional sea water desalination is high in energy consumption, low in recovery rate, poor in environmental protection, and also has the advantages of low cost, strong adaptability, simple operation, provides new type technical path for sea water desalination technology, with remarkable creativity and practical application value.

Description

Technical Field

[0001] This utility model relates to the field of seawater desalination technology, specifically to a melt crystallization system for preparing fresh water. Background Technology

[0002] Seawater desalination technology is an important means of alleviating global water shortages. Currently, the mainstream methods include reverse osmosis (RO), multi-stage flash distillation (MSF), and low-temperature multi-effect distillation (MED). Among these, reverse osmosis technology is relatively energy-efficient (approximately 3-10 kWh / m³). 3 While holding over 60% of the global market share, its core membrane modules are susceptible to fouling and scaling, leading to increased maintenance costs. Furthermore, the energy consumption of high-pressure pumps still accounts for 40%-50% of operating costs. Multi-stage flash evaporation technology, although suitable for high-salinity seawater treatment, consumes as much as 10-25 kWh / m³. 3 Furthermore, the equipment is large-scale and requires high initial investment. Low-temperature multi-effect distillation has improved energy utilization efficiency, but it has strict requirements for heat source temperature, and the complexity of the system limits its widespread adoption.

[0003] Common problems currently faced by the technology include: 1) strong energy dependence, with traditional fossil fuel power generation exacerbating carbon emissions and contradicting the goal of carbon neutrality; 2) the discharge of concentrated brine posing risks to marine ecosystems, such as local salinity imbalances and heavy metal enrichment; and 3) insufficient durability of membrane and evaporator materials, requiring frequent replacement. Therefore, there is an urgent need to develop a new system and method for freshwater preparation. Utility Model Content

[0004] The present invention aims to provide a melting crystallization system for preparing fresh water, in order to solve the problems of unsatisfactory recovery rate and high energy consumption in the existing seawater desalination technology.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: a melt crystallization system for preparing fresh water, comprising a crystallization unit and a distillation unit. The crystallization unit includes a raw material tank, a plate crystallizer, a product tank, and a mother liquor tank. The distillation unit includes a flash tank, a condenser, and a mother liquor concentrate storage tank, wherein the flash tank is connected to the mother liquor tank. Preferably, as an improvement, the feed end of the plate crystallizer is connected to the raw material tank via a pipeline, and a raw material pump is installed between the plate crystallizer and the raw material tank.

[0006] Preferably, as an improvement, the discharge end of the plate crystallizer is also connected to the product tank via a pipeline, and a valve for discharging product / mother liquor / perspiration liquid is provided between the discharge end of the plate crystallizer and the product tank.

[0007] Preferably, as an improvement, the flash tank and the condenser, as well as the condenser tube and the mother liquor concentrate storage tank, are connected by pipelines.

[0008] Preferably, as an improvement, the flash tank is connected to a residual liquid pipeline, which in turn connects to an incinerator.

[0009] Preferably, as an improvement, the plate crystallizer includes a crystallizer housing, and a crystallizer plate assembly is provided inside the crystallizer housing. The crystallizer plate assembly includes at least one crystallizer plate. The crystallizer plate has a cavity inside for accommodating cold / hot media. A baffle plate is fixed on the crystallizer plate, and the baffle plate has baffle holes. The baffle plate is inclined, and the lower end of the baffle plate is fixed to the crystallizer plate.

[0010] Preferably, as an improvement, the crystallization plate is provided with a number of pillow-shaped grooves, which are arranged in a dot matrix pattern.

[0011] Preferably, as an improvement, the crystallization plate group includes several crystallization plates, and several baffles are arranged between two adjacent crystallization plates.

[0012] The principle and advantages of this scheme are as follows: In practical application, this technical scheme utilizes melt crystallization technology to efficiently and economically extract fresh water from saline water sources. During system operation, saline water (such as seawater) enters the plate crystallizer from the raw material tank via a raw material pump. The water is cooled by the cold medium within the crystallization plate cavity, causing water to precipitate in crystal form, while impurities such as salts remain in the mother liquor. After crystallization, a "sweating" process (slow heating) removes the impurities and mother liquor adhering to the crystal surface. The crystals are then heated to melt, yielding preliminary fresh water, which is stored in the product tank. The preliminary fresh water recovery rate can reach 75%. The mother liquor discharged from the crystallization unit (containing high concentrations of salts) is pumped into a flash tank, where residual water is further extracted through heating and evaporation. The steam is condensed into fresh water in a condenser, and the concentrated residue is piped to an incinerator for treatment, avoiding marine pollution. This step achieves secondary resource utilization of the mother liquor, improves the overall fresh water recovery rate, and simultaneously solves the ecological problems associated with traditional concentrated brine discharge. In this technical solution, the raw material tank is also the sweating liquid tank. Fresh raw materials are added for the first crystallization. The generating liquid produced during the sweating process is returned to the raw material tank / sweating liquid tank. At the same time, a small amount of fresh raw materials are added for reuse to ensure the material balance of the entire system. After the sweating liquid is reused, the total crystallization yield is 88%, and the total yield is 90% when the mother liquor is evaporated, concentrated, and recovered.

[0013] Furthermore, this technical solution utilizes a plate crystallizer with a specific structure. The crystallizing plate employs a "cavity + pillow-shaped groove" design: the cavity accommodates cold / hot media to achieve temperature control, while the dot-matrix arrangement of the pillow-shaped grooves increases the heat exchange area and induces turbulence in the liquid, improving heat transfer efficiency. Inclined baffles and baffle orifices work together: the baffles change the liquid flow direction, allowing the brine to splash and fully contact the crystallizing plate; the baffle orifices facilitate the separation of the mother liquor, preventing impurity accumulation and further optimizing the crystallization effect.

[0014] In summary, the beneficial effects of this technical solution are as follows: Through the dual innovation of "system integration + structural optimization", the melt crystallization system of this technical solution not only solves the core problems of high energy consumption (low melt crystallization temperature and low energy consumption, which greatly saves costs compared with traditional MVR technology and membrane separation technology), low recovery rate and poor environmental performance of traditional seawater desalination, but also has the advantages of low cost, strong adaptability and simple operation and maintenance. It provides a new technical path for seawater desalination technology and has significant creative and practical application value. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the melt crystallization system for preparing fresh water according to this invention.

[0016] Figure 2 This is a schematic diagram of the crystallization plate assembly in Embodiment 2 of this utility model.

[0017] Figure 3 for Figure 2 Enlarged view of point A1 in the middle. Detailed Implementation

[0018] The following detailed description provides further details on specific embodiments, but the embodiments of this utility model are not limited thereto. Unless otherwise specified, the technical means used in the following embodiments are conventional means well known to those skilled in the art; the experimental methods used are all conventional methods; and the materials and reagents used are all commercially available.

[0019] The reference numerals in the accompanying drawings include: raw material tank 1, plate crystallizer 2, product tank 3, raw material pump 4, product pump 5, mother liquor tank 6, mother liquor pump 7, flash tank 8, condenser 9, mother liquor concentrate storage tank 10, residual liquid pipeline 11, crystallizing plate 12, pillow-shaped groove 13, baffle plate 14, baffle orifice 15.

[0020] The basic implementation examples are as follows: Figure 1 As shown: A melt crystallization system for preparing fresh water includes a crystallization unit and a distillation unit. The crystallization unit is used for the melt crystallization of seawater, and the distillation unit is used for the concentration of mother liquor.

[0021] The crystallization unit includes a raw material tank 1, a plate crystallizer 2, and a product tank 3. The feed end of the plate crystallizer 2 is connected to the raw material tank 1 via a pipeline, and a raw material pump 4 is installed between the plate crystallizer 2 and the raw material tank 1. The discharge end of the plate crystallizer 2 is also connected to the product tank 3 via a pipeline, and a valve for discharging product / mother liquor / perspiration liquid is installed between the discharge end of the plate crystallizer 2 and the product tank 3. The product tank 3 is connected to a product pump 5 for discharging the product.

[0022] The plate crystallizer 2 is also connected to a mother liquor tank 6, and a mother liquor pump 7 is installed between the mother liquor tank 6 and the distillation unit. The distillation unit includes a flash tank 8, a condenser 9, and a mother liquor concentrate storage tank 10. The flash tank 8 is connected to the mother liquor tank 6 via a pipeline, and the flash tank 8 is also connected to the condenser 9, as well as the condenser tube and the mother liquor concentrate storage tank 10, via pipelines. The flash tank 8 is also connected to a residual liquid pipeline 11, which is connected to an incinerator.

[0023] The specific implementation process of seawater desalination using the above-mentioned melt crystallization system is as follows: S1. Preparation: Clean the plate crystallizer 2 and wash it with deionized water, and connect the cooling device (circulating water cooling).

[0024] S2. Feeding: Surface water is fed into plate crystallizer 2 via raw material tank 1 and raw material pump 4.

[0025] S3. Crystallization: Start the jacket circulation fluid and lower the feed liquid temperature to -5℃. Cool down to an internal temperature of -0.2℃ and a medium temperature of -4.8℃ until no crystals appear. Add seed crystals from the top of plate crystallizer 2, slowly cool down, controlling the internal temperature to -0.3~-3.7℃ and the medium temperature to -4.9~-6.4℃, with a crystallization time of 4 hours. Discharge the mother liquor into mother liquor tank 6, accounting for 10%.

[0026] S4. Sweating: Appropriately raise the medium temperature to -6.3~0℃, control the internal temperature to -4.2~-0.2℃, slowly raise the temperature to induce sweating, sweating time is 7.5h, and the proportion of sweat is 15%.

[0027] S5. Chemical processing: Set the medium temperature to 30℃ and process for 0.5 hours to obtain pure water, accounting for 75%.

[0028] S6. The mother liquor in the mother liquor tank 6 is pumped into the distillation system by the mother liquor pump 7 to concentrate it and obtain pure water. The remaining residue is sent to the incinerator for treatment through the residual liquor pipeline 11.

[0029] Example 2 like Figure 2 As shown, in this embodiment, the structure of the crystallization plate assembly of the box-plate crystallizer 2 is optimized. The crystallization plate assembly is fixed inside the crystallizer and includes several vertically arranged crystallization plates 12. Each crystallization plate 12 has a double-layer structure with a cavity in the middle. The top of each crystallization plate 12 is connected to a medium inlet pipe and a medium outlet pipe. The medium inlet pipe is connected to the medium inlet, and the medium outlet pipe is connected to the medium outlet. Combined with... Figure 3 As shown, the crystallization plate 12 is provided with a number of pillow-shaped grooves 13, which are arranged in a dot matrix.

[0030] The crystallizing plate 12 is also provided with multiple baffle lines arranged along the width direction of the crystallizing plate 12. Several baffles 14 are fixedly connected between two adjacent crystallizing plates 12. The baffles 14 are arranged in a wavy / zigzag shape, that is, the baffles 14 are all inclined. Each baffle 14 is provided with several baffle holes 15, and the diameter of the baffle holes 15 is 5-8mm.

[0031] During crystallization and purification, a cooling medium flows into the cavity of the crystallizer plate 12 through the medium inlet. In this embodiment, the cooling medium is cooling water or ice-salt water. Then, the surface water (seawater) to be purified enters the crystallizer chamber through the material inlet. Under the action of the baffle plate 14, the surface water is splashed, changing the liquid flow direction and increasing the heat exchange area, allowing the surface water to fully contact the crystallizer plate 12 for cooling and crystallization. The formed crystals are retained on the baffle plate 14, while the separated mother liquor falls through the baffle holes 15.

[0032] After purification, the mother liquor is discharged. The cooling medium inside the crystallization plate 12 is discharged through the medium outlet, and the heating medium is added into the cavity of the crystallization plate 12 through the medium inlet. In this embodiment, the heating medium is hot oil or steam. The heating medium heats the crystallized surface water through the crystallization plate 12, causing it to melt and fall from the baffle plate for collection. In this embodiment, through optimization of the crystallization plate assembly structure, the heat exchange area of ​​the same volume is more than twice that of traditional tube-and-shell technology, which can greatly improve the purification efficiency and yield.

[0033] The above descriptions are merely embodiments of this utility model. Commonly known technical solutions and / or characteristics are not described in detail here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the technical solution of this utility model. These modifications and improvements should also be considered within the scope of protection of this utility model, and will not affect the effectiveness of the implementation of this utility model or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A melt crystallization system for preparing fresh water, characterized in that: It includes a crystallization unit and a distillation unit. The crystallization unit includes a raw material tank, a plate crystallizer, a product tank, and a mother liquor tank. The distillation unit includes a flash tank, a condenser, and a mother liquor concentrate storage tank. The flash tank is connected to the mother liquor tank.

2. The melt crystallization system for preparing fresh water according to claim 1, characterized in that: The feed end of the plate crystallizer is connected to the raw material tank via a pipeline, and a raw material pump is installed between the plate crystallizer and the raw material tank.

3. The melt crystallization system for preparing fresh water according to claim 2, characterized in that: The discharge end of the plate crystallizer is also connected to the product tank via a pipeline, and a valve for discharging product / mother liquor / perspiration liquid is installed between the discharge end of the plate crystallizer and the product tank.

4. The melt crystallization system for preparing fresh water according to claim 3, characterized in that: The flash tank and the condenser, as well as the condenser pipe and the mother liquor concentrate storage tank, are all connected by pipelines.

5. A melt crystallization system for preparing fresh water according to claim 4, characterized in that: The flash tank is connected to a residual liquid pipeline, which in turn connects to an incinerator.

6. The melt crystallization system for preparing fresh water according to claim 5, characterized in that: The plate crystallizer includes a crystallizer housing, and a crystallizer plate assembly is provided inside the crystallizer housing. The crystallizer plate assembly includes at least one crystallizer plate. The crystallizer plate has a cavity inside for containing cold / hot media, and a baffle plate is fixed on the crystallizer plate. The baffle plate has baffle holes. The baffle plate is inclined, and the lower end of the baffle plate is fixed to the crystallizer plate.

7. A melt crystallization system for preparing fresh water according to claim 6, characterized in that: The crystallization plate is provided with a plurality of pillow-shaped grooves, which are arranged in a dot matrix pattern.

8. A melt crystallization system for preparing fresh water according to claim 7, characterized in that: The crystallization plate group includes several crystallization plates, and several baffles are arranged between two adjacent crystallization plates.

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