Anhydrous Calcium Chloride Granule

1. Material properties

Calcium chloride (chemical formula: CaCl2) is a colorless cubic crystal, white or off-white, slightly toxic, odorless, and slightly bitter-tasting solid inorganic compound. It belongs to the salt category and is typical ionic halide. It exists in various forms such as granular, honeycomb block, spherical, irregular granular, and powdered. When exposed to air, it is highly deliquescent and easily soluble in water, releasing a large amount of heat. Therefore, it is commonly used in brine for refrigeration equipment, road deicers, and desiccants. Additionally, it can also be used as a food additive, chelating agent, and oilfield well injection agent.

2. Process

Calcium chloride mainly comes from the byproducts of chemical production processes, which are mainly divided into two categories

1) Direct by-product calcium chloride, such as the epichlorohydrin process and the Solvay process for producing soda ash;

2) Hydrochloric acid is produced as byproduct, then it reacted to form the calcium chloride through neutralization reaction, such as in the caustic soda industry, the Mannheim potassium sulfate industry, the fluorochemical industry, and the polysilicon industry.

Regarding the significant environmental protection impact and difficult treatment of hydrochloric acid as the byproduct, calcium chloride production plants offer an optimal solution. The calcium chloride production facility is simple and requires low investment. At the same time, the demand for calcium chloride products is high and stable, with a broad market prospect, enabling hydrochloric acid to transition from loss-making treatment to profitable revenue generation.

Relying on its strong R&D capabilities and rich experience from dozens of calcium chloride projects, Tianli has developed mature, stable, unique, and efficient calcium chloride production process. It provides customers with one-stop service including design, supply, installation, commissioning, and after-sales service, perfectly solving the dilemma of difficult hydrochloric acid and calcium chloride treatment.

The anhydrous granular calcium chloride production unit mainly includes neutralization reaction section and spray granulation section:

1) Neutralization reaction section

The process uses hydrochloric acid and limestone as raw materials, which undergo neutralization reaction in reactor. The pH value is then adjusted with CaO, and the solution is purified by pressure filtration to obtain pure calcium chloride solution.

2) Spray granulation and drying section

The finished calcium chloride solution from the neutralization reaction is fed into a granulation fluidized bed dryer. After being atomized by an atomizing spray gun, it collides, contacts, and adheres to the seed crystals in the dryer. Then, it is dried by high-temperature air to complete the drying and granulation process. After sieving, the finished granular anhydrous calcium chloride product is obtained.

This section uses natural gas or diesel as heat source to generate hot air as drying medium for material drying. The exhaust gas after drying is purified by cyclone and two-stages scrubber before being discharged into atmosphere.

3. Technological advantages

1) Neutralization reaction

a. The reaction between hydrochloric acid and limestone is continuous process, ensuring the continuous and stable operation of the system;

b. The special design of the reactor structure can ensure that the reaction between hydrochloric acid and limestone is full, rapid and efficient, which greatly improves the utilization efficiency of hydrochloric acid and limestone, while reducing the amount of CaO used in the pH adjustment section and reducing raw material investment.

c. Based on the above advantages, the reactor does not need to be cleaned during operation, which greatly reduces the workload and extends the system's operating cycle;

d. The exhaust gas scrubber is designed to meet the characteristics of the system, ensuring that the carbon dioxide and HCl produced during the reaction process are discharged in compliance with emission standards.

2) Spray granulation and drying section

a. The system adopts a linear burner operating under positive pressure and is equipped with an automatic monitoring and control system that includes temperature monitoring, flame monitoring, pressure monitoring, and gas leak monitoring. Compared with a powerful burner operating under negative pressure, it has higher temperature regulation accuracy and a higher safety factor. At the same time, natural gas combustion is more complete and the utilization rate is higher, which can reduce energy consumption.

b. Based on the positive pressure operation of the linear burner, the system blower is placed before the gas furnace and operates at normal temperature. Compared with the high temperature operating environment of the blower matched with the negative pressure operation gun burner, the service life of the blower is extended by 300% and the failure rate is reduced by 70%.

c. The primary scrubber uses the finished calcium chloride solution from the reaction section as the scrubbing liquid. While washing and absorbing calcium chloride dust in the exhaust gas, it also absorbs heat from the exhaust gas, causing moisture to evaporate. This two-pronged approach increases the concentration of the calcium chloride solution. This process ensures that the exhaust gas meets emission standards while fully absorbing heat from the exhaust gas, reducing natural gas consumption by 15%.

d. The system's atomizing nozzles have undergone extensive experimental research and development, resulting in better atomization effects, more uniform atomized particle size, more uniform product particle size, and higher tube curl.

e. Based on the characteristics of the exhaust gas and calcium chloride in the drying system, the structure of the exhaust gas scrubber was specifically designed, and corresponding patents were obtained. Furthermore, after verification through numerous engineering cases, it fully meets the exhaust gas purification requirements.

f. In view of the fact that calcium chloride is hygroscopic and the chloride ions produced after deliquescence are highly corrosive, our company selects materials with better chloride ion corrosion resistance, such as HC276/2205, when designing key equipment and components of the production plant to ensure the stable operation and service life of the system.