Sodium Chloride
Sodium chloride (NaCl), commonly known as table salt, is a widely used inorganic ionic compound. As a core raw material in food seasoning, chemical raw materials, and pharmaceutical preparations, the sophistication of its production process directly determines product quality and application value. Tianli has deep expertise in sodium chloride production, focusing on the two core processes of evaporation and drying. We leverage our professional technology to upgrade the products, creating high-purity, high-stability sodium chloride products to comprehensively meet the stringent requirements of various industries.
I. Core Properties of Sodium Chloride
Sodium chloride is a colorless cubic crystal or white crystalline powder with the chemical formula NaCl. Its relative molecular mass is 58.44, density is 2.17 g/cm³, melting point is 800.7℃, and boiling point is 1413℃. It is odorless, has a salty taste, and exhibits slight hygroscopicity, which is more pronounced when impure. Its aqueous solution is neutral, with a solubility of 360 g/L at 25℃. The solubility is minimally affected by temperature changes. This characteristic dictates that crystallization requires supersaturation precipitation through water evaporation, which is also the core design basis for the evaporation section. Sodium chloride is highly stable, does not react with most substances, is readily soluble in water and glycerol, and slightly soluble in methanol. It is widely found in seawater, salt lakes, and rock salt mines, making it a high-quality raw material source for industrial production.
II. Core Process Flow Introduction
Tianli can provide one-stop service including design, supply, installation, commissioning, and after-sales service for both the evaporation and concentration and sodium chloride drying processes in sodium chloride production.
(1) Evaporation Section
The evaporation stage is the core of sodium chloride production. Its main purpose is to evaporate the solvent (water) to achieve a supersaturated state in the sodium chloride solution, allowing crystals to precipitate and removing soluble impurities. Our company employs the industry-leading multi-effect vacuum evaporation process, coupled with a forced-circulation crystallizer, adapted to the solubility characteristics of sodium chloride, significantly improving production efficiency and product purity.
The process flow follows the core logic of preheating - multi-effect evaporation - crystallization - solid-liquid separation: After being preheated to a suitable temperature, the refined sodium chloride solution sequentially enters the fourth to fifth effect evaporators. Live steam is introduced into the first effect as a heat source, and subsequent effects utilize the secondary steam generated in the previous effect for heating, achieving heat energy recycling and reducing energy consumption. A negative pressure is maintained within the evaporators to lower the boiling point of the solution and accelerate water vaporization. The solution continuously flows in the forced circulation system, preventing localized overheating and crystallization. When the concentration of the feed solution reaches saturation, sodium chloride begins to crystallize and precipitate. After being screened by the grading device in the crystallizer, uniformly sized crystals are formed. Then, wet sodium chloride crystals are obtained by centrifugation. The separated mother liquor is recycled back to the evaporation system to improve the utilization rate of raw materials.
(II) Drying Section
Tianli offers two drying systems: internally heated fluid bed dryers and steam rotary dryers. Both systems incorporate heat exchange tubes for heating and drying the material. Wet sodium chloride crystals enter the dryer via a conveying device, where they directly contact the heat exchange tubes for heat exchange, completing the drying process and significantly reducing heat loss.
The dried sodium chloride crystals are then cooled, conveyed, and screened to remove impurities, ultimately yielding the finished sodium chloride product. This product can be processed into different specifications, such as crystalline or powdered forms, to suit various applications in the food, chemical, and pharmaceutical industries.
III. Core Technical Advantages
1. Energy-efficient and cost-controllable. The multi-effect vacuum evaporation process fully utilizes secondary steam, increasing thermal energy utilization by over 60% compared to single-effect evaporation, significantly reducing live steam consumption. The drying section employs hot air circulation recovery technology, reducing heat loss and lowering overall energy consumption by 30% compared to traditional processes, effectively controlling production costs.
2. The material in the drying system directly contacts the heat exchange tubes, facilitating heat exchange and greatly reducing heat loss, resulting in a 30% reduction in steam consumption.
3. The increased number of internal heat exchange tubes reduces the amount of hot air required for the drying system, resulting in a smaller footprint for the main equipment and a smaller exhaust gas dust removal system, significantly reducing civil engineering and equipment investment.
4. High-quality products with high purity. Through precise control of evaporation temperature, pressure, and drying parameters, combined with grading and impurity removal processes, sodium chloride purity ≥99.3% can be achieved, with uniform crystal particle size, stable moisture content, and no impurity residue, meeting multiple standards such as food-grade, industrial-grade, and pharmaceutical-grade, adaptable to diverse application scenarios.
5. Safe, Stable, and Environmentally Friendly. The entire process adopts a closed-loop design, recycling the mother liquor and eliminating wastewater discharge. The evaporation and drying processes are operated in a completely sealed environment, preventing dust leakage and material contamination. It is also equipped with intelligent temperature control and pressure monitoring systems to eliminate safety hazards such as overheating and leakage, achieving green and safe production.
6. Intelligent and Controllable, Flexible Adaptability. The process section is equipped with a fully automatic control system that can monitor key parameters such as feed concentration, temperature, and moisture content in real time, precisely adjusting the process flow to adapt to the production needs of different raw material concentrations and product specifications. It is easy to operate and highly stable, significantly reducing manual intervention costs.
We are deeply rooted in core processes and creating high-quality products. Based on the characteristics of sodium chloride, Tianli optimizes the evaporation and drying process technology. Leveraging its core advantages of energy saving, high efficiency, and environmental protection, we provide high-purity, high-stability sodium chloride products to various industries, empowering industrial upgrading with professional technology and creating value together with our customers.