The resource utilization technology of high concentration brine in coal chemical industry is an important field for wastewater treatment and resource recovery in the current coal chemical industry. Among them, thermal salt separation and membrane salt separation are two main technical methods. The following is a detailed analysis of these two technologies:

      1、 Thermal Salt Separation

        Thermal salt separation is a treatment process that utilizes the different solubility of each component in a mixture in the same solvent or the significant difference in solubility under cold and hot conditions, and uses crystallization to separate them. The basic principle is to precipitate solutes from a solution in the form of crystals by lowering the temperature or evaporating the solvent.

      Technical features:

        Suitable for substances whose solubility changes significantly with temperature.

        In industry, it is often used in combination with concentration. The solution is first concentrated, and then the solute crystals are obtained by cooling and heating the saturated solution crystallization method.

        Evaporative crystallization is suitable for substances whose solubility does not change significantly with temperature.

    Application scenarios:

        Commonly used for salt nitrate co production, it requires brine with high purity of raw materials and controls the salt nitrate ratio within a certain range.

        For industrial wastewater with complex components, the purity and recovery rate of salt separation may be low.

      Advantages and disadvantages:

        Advantages: Slightly lower investment and lower operating costs.

        Disadvantage: The purity of the final product salt is significantly affected by the incoming material. Under high salt content conditions, the solubility of the salt is affected by other ions, which can change the solubility and even form difficult to precipitate blended salts, reducing the purity and yield of sodium sulfate and sodium chloride.

      II. Membrane Salt Separation

        Membrane salt separation is a treatment process that utilizes the selective permeability of nanofiltration membranes to effectively separate monovalent and divalent salts in a solution. Nanofiltration membrane is a thin layer composite membrane with a molecular weight cutoff ranging from 200 to 1000. It can dialyze over 90% NaCl and is suitable for various processes such as desalination, monosaccharide removal, and concentration.

      Technical features:

        Nanofiltration membranes have a multi-layered porous structure and exhibit high permeate flux under high salinity and low pressure conditions.

        Inorganic salts can be dialyzed through nanofiltration membranes, resulting in a much lower osmotic pressure for nanofiltration compared to reverse osmosis, and requiring lower external pressure.

        Nanofiltration can synchronize the special concentration and separation equipment with the desalination process, and the concentration process can be effectively and quickly carried out, achieving a large concentration multiple.

      Application scenarios:

        Suitable for the resource utilization of high concentration salt water in coal chemical industry, it exhibits advantages such as organic matter interception and thorough salt separation.

        It can also be used to treat other wastewater containing different types of salts.

      Advantages and disadvantages:

        Advantages: Simple operation, good organic matter retention effect, and thorough salt separation.

        Disadvantages:The performance of nanofiltration membrane deteriorates quickly, the recovery rate is low, and the salt separation effect will deteriorate over time.

      3、 Technical Comparison and Combined Application

      Comparison:Thermal salt separation and membrane salt separation each have their own advantages and disadvantages. Thermal salt separation technology is mature but product purity is limited, while membrane salt separation is simple to operate but requires stable membrane performance.

      Combined application: Due to the fact that a single salt separation technology often cannot completely separate impurities, existing "zero emission" coal chemical engineering projects often adopt a combination process of membrane concentration coupled with thermal evaporation. This combination process combines the efficient separation of membrane salt separation with the crystallization ability of thermal salt separation, achieving the resource utilization and near zero discharge of high concentration saltwater.

        The thermal separation and membrane separation of highly concentrated salt water in coal chemical industry have their own characteristics and advantages in resource utilization technology. Baihuipu Environmental Protection is a one-stop service manufacturer for research, production, and sales, with multiple sub factories and subsidiaries, serving multiple leading domestic and foreign enterprises. It has passed ISO9001 system certification and has been specializing in evaporator production and overall solutions for many years. On site survey * formulation of plans * equipment production * installation and after-sales one-stop service, 10 second quotation, 30 minute solution, 24-hour on-site service, find Baihuipu Environmental Protection for evaporation and concentration equipment!