Definitions, drying objectives and competing techniques

For the purposes of this presentation, the product is assumed to be made up of two components:

• Dry matter is considered to be non-volatile, unlike the solvent (water), even if in reality other volatile molecules than the water to be dried may also escape in the form of vapor (loss of aromas, release of odors, volatile organic compounds or VOCs...), which will be neglected here in terms of mass and energy. When separation is based on the differential volatility of components, the operation is more akin to distillation. Dry matter is generally the most valuable fraction of the product, although in certain cases (e.g. organic solvents, odors, etc.) the solvent may also be recovered.

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