FLUID BED SALT DRYING REDUCING ENERGY COST Most of the salt production has its origins in the sea, being either harvested directly from sea water or derived from rock salt deposits (former seas which have evaporated many millions of years ago). There are three types of salt extraction: rock salt mining, solution mining (dissolving the salt in water, called brine) and solar evaporation. Rock Salt Mining There are many hundreds of horizontal and vertical salt layers across the world. Mines vary in depth from 100 metres or so, to 1 ½ kilometres. There are two main methods of extracting rock salt – ‘Cut and Blast’ mining and ‘Continuous’ mining. Solution Mining In the process of solution mining, water is forced under pressure into a bore-hole drilled into an underground salt layer. The salt dissolves, turning the water into brine and creating a cavern in the salt-layer. Controlling the amount of water introduced and the rate of extraction ensures that the size of this cavern is fully controlled, minimising the risk of subsidence. Ventilex Salt dryer Benefits: High energy savings—up to 40% Eliminates corrosion Reduced wear-and-tear Rugged construction Long lifetime, reliable dryers Low maintenance Advanced control strategies Accurate product temperature control Abrasive materials without excessive wear Construction of large corrosion resistant Saltdryer in workshop Heerde The saturated raw brine is then withdrawn and pumped to the purification plant where calcium, magnesium and other impurities are removed prior to the evaporation process. In the first step of the evaporation process, brine is pumped into the first of a series of vessels which also contain special steam chambers. The heat of the introduced steam causes the brine to boil and water evaporates. This in turn produces further steam and causes salt crystals to grow. These salt crystals and associated brine slurry are fed into a second vessel where the process is repeated (using exhaust steam from the first vessel). Pressures (and boiling temperatures) become successively lower through the evaporators. The final ones operate under vacuum and enable the brine to boil at much lower temperatures, which is more fuel-efficient. The salt crystals and slurry from the final vessel is fed into a centrifuge to extract more moisture and the resulting undried vacuum salt is then stored in bulk, for supply to the chemical industry.

Salt for food and other uses which needs to be drier, the undried vacuum salt from the centrifuges is fed into the Ventilex fluidized-bed dryers. The salt is then sieved and graded – Iodine can also be added at this stage – before being transferred into large storage hoppers ready for distribution in bulk and bags. Solar Evaporation Probably the earliest method of production, producing salt from the sea, involves channelling sea water to flow into natural or man-made basins and allowing the water to evaporate using wind and solar energy. The water evaporates in successive ponds until the brine...

How does a Ventilex Fluidbed Saltdryer work In a continouos fluidbed dryer/cooler a continuous flow of wet granular material is dried and subsequently cooled. Drying of the material occurs by direct contact between the material to be dried and the hot drying air that is blown through a layer of product. In food related salt production corrosion is not the only challenge to be overcome. Everything has to be designed keeping hygiene in mind. Ventilex can supply fluid bed dryers with foodgrade design and manufacturing and on top of that there several extra options are available. Cleaning in place...

Why Ventilex Drying systems for salt products can also consume a lot of energy leading to significantly higher operational costs and low margins. Greater wear-and-tear on account of the abrasive nature of the materials being processed also means frequent maintenance and repairs or replacement expenses. Leading parties in the salt industry have already chosen for a Ventilex Fluid Bed system. It is space saving, energy-saving and there is no product loss. Customers also indicate that their installation and maintenance costs are significantly lower. The shaking forces of the Ventilex Fluid Bed Dryers...