Product Introduction

　　 Freezing crystallization equipment It is a new type of separation and crystallization equipment based on the principle of “solvent solidification and separation at low temperatures.” At its core, it employs “low-temperature freezing plus solid-liquid separation” technology. By cooling the feed liquid below the freezing point of the solvent—typically water—the solvent forms crystals (ice or solvent crystals), thereby separating it from the solute (such as salts or organic compounds) and enabling either solute concentration or solvent recovery. The equipment’s key advantages include “low operating temperature, gentle and non-destructive processing, high solvent recovery rate, and environmental friendliness.” It is widely used in industries such as chemical engineering, environmental protection, food processing, and pharmaceuticals for concentrating heat-sensitive materials, treating high-salinity wastewater, recovering solvents, and performing low-temperature crystallization processes. It is particularly well-suited for handling heat-sensitive, easily oxidized materials that cannot withstand high-temperature evaporation. The freezing system and separation structure can be customized according to the characteristics of the feed liquid (such as freezing point, viscosity, and solute concentration) to achieve highly efficient separation and crystallization.

Product Category

　　According to the freezing method, equipment structure, and application scenarios, freezing crystallization equipment is mainly categorized as follows:

　　 1. Classified by freezing method

　　 ▪ Indirect freezing crystallization equipment: The material liquid is cooled by indirect heat exchange with a refrigerant (such as an ethylene glycol solution or liquid nitrogen). The material liquid does not come into direct contact with the refrigerant, ensuring safety and hygiene, and making it suitable for applications in industries such as food and pharmaceuticals that have high purity requirements.

　 　▪ Direct freezing crystallization equipment: The refrigerant (such as liquid nitrogen or carbon dioxide) is directly introduced into the feed solution, rapidly lowering the temperature and forming ice crystals. This method boasts high freezing efficiency and is particularly suitable for large-scale wastewater treatment and emergency cooling crystallization scenarios.

　 　▪ Vacuum freeze-crystallization equipment: By utilizing a vacuum environment to lower the boiling point and freezing point of the solvent, the feed liquid undergoes self-evaporation and cooling under vacuum, thereby forming crystals. This process features low energy consumption and is particularly suitable for the deep concentration of heat-sensitive materials.

　 　2. Classified by Equipment Structure

　 　▪ Batch-type freezing crystallizer: Batch operation, with individual reactor volumes ranging from 0.5 m³ to 20 m³. Featuring a compact structure and precise temperature control, this equipment is ideal for crystallization of small-batch, multi-variety materials (such as pharmaceutical intermediates and fine chemical products).

　 　▪ Tubular freezing crystallizer: Continuous operation, featuring a tube-in-tube or shell-and-tube structure: the feed liquid flows inside the tubes, while the refrigerant exchanges heat in the shell side. This design offers high crystallization efficiency and is well-suited for medium- to large-scale continuous production.

　　 ▪ Plate-type freezing crystallizer: Modular plate-type structure with large heat transfer area, rapid cooling speed, and compact footprint—ideal for applications with space constraints and the need for flexible scalability (such as small- and medium-sized chemical enterprises and food processing plants).

　　 ▪ Suspended-bed freeze crystallizer: The feed liquid is in a suspended state within the crystallizer, ensuring uniform contact between the crystals and the feed liquid. The crystal size is uniform and well-regulated, making this process suitable for feed liquids with high viscosity and containing small amounts of suspended solids.

　 　3. Classified by process flow

　　 ▪ Single-stage freeze crystallization system: Single-step freezing and separation achieves solute concentration or solvent recovery. It features a simple structure, low investment costs, and is suitable for preliminary separation applications (such as wastewater pretreatment and initial material concentration).

　 　▪ Multi-stage freezing crystallization system: Two-to-four-stage freezing units are connected in series to gradually reduce the temperature, thereby enhancing crystal purity and solvent recovery rate, making them suitable for high-demand separation applications (such as high-purity solvent recovery and deep concentration of heat-sensitive materials).

　 　▪ Frozen - Washing - Melting Integrated System: Integrates freeze crystallization, crystal washing, and solvent melting & recovery functions to achieve highly efficient separation of solute from solvent. The solvent recovery rate can reach 90%–99%, making it suitable for resource recovery applications.

Performance Features

　 　1. Gentle separation without damage: The operating temperature is low (-30℃ to 0℃), significantly lower than that of conventional evaporation processes, which can effectively prevent the decomposition, oxidation, and denaturation of heat-sensitive materials (such as enzyme preparations, biological extracts, and pharmaceutical intermediates), thereby maximizing the preservation of their original properties.

　 　2. High solvent recovery rate: Solvent crystals (such as ice crystals) have high purity. After being washed and melted, the solvent recovery rate can reach 90% to 99%, making them particularly suitable for wastewater reuse in regions with water scarcity and for scenarios involving the recovery of high-value solvents.

　 　3. Green and environmentally friendly, low energy consumption: No high-temperature heating is required, and energy consumption is only 1/4 to 1/2 of that of conventional evaporation equipment. Moreover, there are no exhaust gas emissions, and the mother liquor can be recycled, fully complying with environmental protection policies. The direct freezing type can utilize industrial waste heat or waste cold, further reducing energy consumption.

　 　4. Wide compatibility: It can handle various solutions with solute concentrations ranging from 5% to 30%. It is compatible with materials having low viscosity (<500 mPa·s) up to medium-to-high viscosity (<1500 mPa·s). By customizing material selection (such as 316L stainless steel or titanium), it can be adapted to corrosive media. It is particularly well-suited for processing special materials that are heat-sensitive, prone to oxidation, or cannot be evaporated at high temperatures.

　 　5. Excellent crystal quality: By precisely controlling the temperature (temperature control accuracy ±0.5℃) and optimizing stirring, crystal particle size can be effectively controlled (ranging from 0.1 mm to 5 mm). The resulting crystalline products exhibit high purity, uniform morphology, and no residual solvents, making subsequent drying and shaping processes convenient and efficient.

　 　6. Stable and controllable operation: The freezing system is linked to the separation unit for coordinated control, allowing flexible adjustment of parameters such as cooling rate, crystallization time, and separation pressure to accommodate different feed liquid characteristics. The continuous equipment can operate continuously for 24 hours, ensuring stable production capacity.

　　 7. Safe and reliable: Indirect cooling systems carry no risk of refrigerant contamination, while direct cooling systems using refrigerants such as liquid nitrogen are non-toxic and harmless. These systems operate at low pressures (atmospheric or low pressure) and pose no safety hazards such as explosions or high-temperature burns.

Application scenarios

　　Thanks to its core advantages of low temperature, mild conditions, and being green and efficient, freeze-crystallization equipment is widely used in the following industries:

　 　1. Pharmaceutical industry: Concentration of biopharmaceutical intermediates (such as enzyme preparations and vaccine bulk solutions), crystallization of heat-sensitive active pharmaceutical ingredients (such as antibiotics and hormones), low-temperature concentration of traditional Chinese medicine extracts (to prevent degradation of active components), and treatment of pharmaceutical wastewater (to recover solvents and water resources).

　 　2. Food industry: Fruit juice concentration (e.g., mango juice, blueberry juice, preserving vitamins and flavor compounds); dairy processing (e.g., whey protein concentrate, crystallization of ice cream ingredients); natural extract concentration (e.g., tea polyphenols, anthocyanins); food additive crystallization (e.g., high-purity lactose, maltose).

　 　3. Chemical Industry: Crystallization of fine chemical products (such as thermally sensitive organic compounds and dye intermediates), recovery of high-value solvents (such as ethanol, acetone, and ethyl acetate), zero discharge of chemical wastewater (freezing desalination of high-salinity wastewater to recover pure water), and separation of azeotropic systems (mixtures that cannot be separated by distillation).

　 　4. Environmental Protection Industry: High-salt wastewater treatment (such as high-salt wastewater from chemical industrial parks, electroplating wastewater, and recovery of water resources through cryogenic desalination); leachate treatment from solid waste (low-temperature concentration to reduce subsequent treatment costs); organic wastewater solvent recovery (such as recovery of organic solvents from printing wastewater and coating wastewater).

　 　5. Other fields: Bioengineering (such as fermentation broth concentration and enzyme preparation purification), cosmetic raw material processing (such as hyaluronic acid and collagen concentration), low-temperature crystallization experiments in laboratories, and the preparation of special materials (such as low-temperature synthesis of crystalline materials).