PROCESS DESCRIPTION

1. Calcium chloride properties and uses

As one kind of inorganic salts, Calcium chloride (CaCl₂) is a white crystal with unique physical properties such as high solubility, moisture absorption and easy hydrolysis in the air. When the concentration of calcium chloride solution is 30%, it does not freeze at the low temperature of -55 ℃. Therefore, it can be used as desiccant, refrigerant, de-icing agent and coagulant and is widely used in chemical, mining, construction, transportation, Smelting, medicine, light industry, food, storage and other industries

2. Process description

1) Raw material: 31% hydrochloric acid & lime stone (10-30mm)

2) Process description

The reaction equation is shown below,

CaCO₃ + 2HCl = CaCl₂ + CO₂ + H₂O

Add the lime stone (CacO₃) to the reactor evenly. Hydrochloric acid (byproduct) is pumped by the Hydrochloric acid pump and metered to the reactor. In the condition of slight negative pressure, the added stone and acid in the reactor react to prepare Calcium chloride mother liquid. During in the reaction process, CO₂ is emitted with a small amount of HCl tail gas. The acidic waste gas from the reactor and Hydrochloric acid buffer tank is collected to the tail gas absorption system, where the waste gas is through a staged absorption cycle with Calcium chloride solution and alkaline liquor, and then the treated waste gas reaching environmental standard will be exhausted by an 8-meter high stack.

The reactant, acidic Calcium chloride solution, goes to a neutralizing tank, where Ca(OH)₂ emulsion is added to adjust pH value. At the normal temperature and pressure, neutralization and purification go on. The produced slurry will settle down at the bottom of the neutralizing tank. The neutralized Calcium chloride solution goes to a filter press by a filter press pump. After filtration, the clear solution is transferred to Calcium chloride mother liquid tank for storage. The filtered sludge cake falls to a sludge hopper and is trucked periodically for sale.

The reaction solution first enters the concentration section, and after reaching the concentration of 68%, it is directly fed into the flaking machine, and then transferred to a fluidized bed to dry to 77%, and the yield is 1400 kg/h. This plan includes evaporation section, flaking-drying-packing section, PLC control system and power system.

First, the stable saturated steam produced by the fuel steam boiler is sent to the evaporation equipment.

The raw material, Calcium chloride solution, first enters the preheater and exchanges heat with the condensed water in the heating chamber to above 80 ° C, then enters the second-effect evaporator to heat and evaporate, and then enters the first-effect evaporator to continue evaporation and increasing concentration. When the concentration reaches the requirement, it is discharged to the flaking machine.

The Calcium chloride flakes from the flaking machine enter the fluidized bed to heat transfer and mass transfer with the hot air blown by the blower. This is the drying process, which can dry Calcium chloride particles to 77%. The tail gas of the drying process carries a part of the calcium powder and enters the cyclone to remove dust. After that, the tail gas goes to water-bath dust collector for absorption, and then the gas is discharged into the atmosphere after it meets the environmental protection requirements.

3). Consumption

Raw material:  HCL (31%): 1.89/t; lime stone (98% CaO): 0.72t/t

Fuel: Natural gas (8700 Kcal/m3): 150Nm3/t, diesel (9700Kcal/m3): 130kg/t.