Potassium chloride evaporation crystallization equipment

Working Principle 

Potassium chloride evaporation crystallization equipment mainly utilizes the principle of evaporation crystallization. By heating a potassium chloride-containing solution, the water evaporates, achieving a supersaturated state, causing potassium chloride to crystallize and precipitate. Based on the solubility characteristics of potassium chloride, the equipment typically employs the following methods:

Evaporation Method: Achieving supersaturation by removing part of the solvent. Suitable for potassium chloride solutions where solubility does not change significantly with temperature.

Vacuum Cooling Method: The solvent flashes and evaporates under vacuum conditions, while the solution is adiabatically cooled for crystallization. Suitable for substances like potassium chloride where solubility increases at a moderate rate with increasing temperature.

Equipment Types

Multi-Effect Evaporation Crystallizer: Utilizes multiple evaporators connected in series, achieving potassium chloride concentration and crystallization through multiple evaporation and condensation processes. For example, a triple-effect evaporator uses a series of evaporators (first, second, and third effects) to evaporate in stages, using the steam generated in the previous effect as a heat source for the next effect, improving energy efficiency.

MVR Evaporation Crystallizer: Employs mechanical vapor recompression (MVR) technology, compressing the secondary steam generated during evaporation to increase its temperature and pressure, then using it as a heat source, resulting in significant energy savings.

External circulation crystallizer: Composed of a crystallization chamber, circulation pipes, circulation pump, heat exchanger, etc., it is suitable for crystallization by evaporation, indirect cooling, or vacuum cooling methods, and is suitable for producing crystals such as potassium chloride.

Process Flow: 

Taking a triple-effect evaporator crystallizer as an example, the process flow includes:

1. Solution preheating: Preheating the potassium chloride-containing solution to improve evaporation efficiency.

2. First-effect evaporation: The preheated solution is fed into the first-effect evaporator, where it is heated and some water is evaporated, generating first-effect steam.

3. Second-effect evaporation: The first-effect steam serves as the heat source for the second-effect evaporator, allowing the solution in the second-effect evaporator to continue evaporating, generating second-effect steam.

4. Third-effect evaporation: The second-effect steam then serves as the heat source for the third-effect evaporator, further evaporating the water in the solution.

5. Crystallization and separation: In the triple-effect evaporator, as water continues to evaporate, potassium chloride gradually concentrates and crystallizes. Finally, the potassium chloride crystals are separated from the mother liquor by centrifugation or filtration.

Equipment Features

• Fast and Energy-Saving: The application of multi-effect evaporation and MVR technology significantly improves energy utilization efficiency and reduces energy consumption.

• High Automation: Equipped with a PLC or DCS control system, it achieves fully automatic operation, reducing manual intervention and improving production efficiency.

• Strong Corrosion Resistance: Utilizing corrosion-resistant materials such as titanium and Hastelloy, it extends equipment lifespan.

• High Resource Recovery Rate: High recovery rate and high purity of potassium chloride crystals enable resource utilization.

Application Scenarios

Potassium chloride evaporation crystallization equipment is widely used in chemical, pharmaceutical, and environmental protection industries, primarily for treating wastewater containing potassium chloride, achieving potassium chloride recovery and water resource reuse. For example, in high-salinity wastewater treatment, evaporation crystallization technology separates potassium chloride from the wastewater, reducing salinity and meeting environmental discharge standards.