EBNER, together with its partners, won the contract in 2016 for the planning, delivery and installation of a multi-stage plant for the vacuum cooling crystallization of potassium chloride from clarified hot solution from the largest potash producer in Belarus.
The system designed by EBNER serves the customer to expand the production capacity and to replace a system that has been in use for a long time. In general, potassium chloride, which is obtained by mining, can be converted into salable fertilizer in two main processes:
1. Vacuum cooling crystallization
The system operates on the principle of vacuum cooling crystallization and is integrated into the typical production process for the production of the fertilizer potassium chloride as follows:
1. Mining of raw ore
2. Hot dissolving: Dissolving of the salts KCl and NaCl contained in the raw ore and removing of insoluble constituents
3. Vacuum cooling crystallization: Cooling of the solution and thus precipitation of KCl with the addition of water, so that NaCl remains in solution
4. Salt separation or after treatment: Separation of solution and e.g. compaction / granulation of the KCl salt
The hot solution is introduced at about 90 – 100°C in the system. In each stage of the system, water is evaporated from the inlet solution by applying a vacuum. As a result, the solution heat is removed and thus cooled down. As the solubility of KCl decreases with decreasing temperature, the solubility is exceeded and salt crystallizes. Then, the resulting suspension is passed to the next stage and cooled again by the described method. Thus the previously generated crystals grow. By repeating this procedure, the solution is finally cooled to about 30°C and added to the salt separation or after treatment.
The lye separated in the salt separation is returned to the hot dissolving to dissolve new salt. In order to achieve a solution-temperature as closely as possible to that in the hot dissolving, the solution is used to condense the largest possible part of the incurred vapour steam in the vacuum cooling crystallization. As a result, the heat is recovered to the greatest extent possible. The rest of the heating happens through the use of live steam.
The production plant is of great importance to the customer as this is the core of the production. EBNER and partners were awarded the contract for this order mainly because of the good reputation, customer focus and the highly efficient heat recovery of the vacuum cooling crystallization plant.