Description

Project Background

In the chlor-alkali industry, the conversion of by-product hydrochloric acid into calcium chloride is a widely adopted solution that enables both environmental compliance and resource utilization. By reacting hydrochloric acid with limestone, followed by filtration and clarification, a clear calcium chloride solution with a concentration of approximately 35% is produced.

This intermediate solution can be further processed into a range of commercial products, including flake calcium chloride dihydrate, spherical calcium chloride dihydrate, and spherical anhydrous calcium chloride, which are widely used in deicing, dust control, oilfield services, and drying applications.

To meet different product requirements, the calcium chloride solution must be concentrated to higher levels. Typically, a concentration of around 55% is required for the production of spherical calcium chloride products, while concentrations above 68% are needed for flake calcium chloride production.

However, calcium chloride solutions present significant challenges during concentration, including high boiling point elevation, increasing viscosity, and scaling tendencies at elevated concentrations. These factors require a more advanced and efficient evaporation solution.

Our hybrid calcium chloride evaporator system is specifically designed to address these challenges. By integrating multiple-effect evaporator with a final-stage falling film concentrator, the system ensures high energy efficiency, stable operation, and consistent product quality.

The system is flexibly designed to produce both 55% and 68% calcium chloride solutions, enabling manufacturers to adapt to different product requirements with a single integrated solution. With proven performance and optimized design, it achieves efficient concentration from 35% feed while reducing energy consumption, minimizing fouling, and ensuring reliable long-term operation.

Equipment Description 

The hybrid calcium chloride evaporator system is designed for the efficient concentration of calcium chloride solutions from approximately 35% to 55% or 68%, meeting the requirements for both spherical and flake product production. The system combines multiple evaporation technologies to achieve an optimal balance between energy efficiency, operational stability, and product quality.

• Double-Effect Forced Circulation Evaporator

This section adopts a double-effect forced circulation design equipped with high-flow, low-head axial circulation pumps. Continuous circulation of the solution within the heat exchange tubes effectively reduces scaling tendencies and extends cleaning intervals. In this stage, the calcium chloride solution can be concentrated up to approximately 55% for spherical product production, or above 60% for flake product production.

• Final Falling Film Concentrator

Directly concentrating the solution to 68% in the forced circulation system would significantly increase the risk of scaling and tube blockage due to the high viscosity and supersaturation of the solution. Therefore, a single-effect falling film evaporator is introduced as the final concentration stage. This configuration enables efficient and gentle concentration to the target level while minimizing fouling and avoiding operational issues such as tube plugging.

Through this hybrid configuration, the system ensures high efficiency in the initial evaporation stages and reliable operation during high-concentration processing, providing a stable and flexible solution for calcium chloride production.

Key Advantages

• Flexible Product Output

Capable of producing both ~55% and ≥68% calcium chloride solutions within a single system, supporting the production of spherical and flake products.

• High Energy Efficiency

Multiple-effect evaporation significantly reduces steam consumption, lowering operating costs and improving overall energy utilization.

• Reduced Scaling and Fouling

Forced circulation design combined with optimized flow conditions minimizes scaling risks and extends cleaning intervals.

• Reliable High-Concentration Operation

Final-stage falling film concentrator ensures stable and safe operation when handling high-viscosity, high-concentration solutions, avoiding tube blockage.

• Stable and Continuous Performance

Engineered for long-term, continuous operation with consistent product quality and minimal downtime.

• Lower Maintenance Costs

Optimized design reduces fouling, wear, and cleaning frequency, resulting in lower maintenance requirements and lifecycle costs.

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