Batch Drying: Maximizing Product Yields

Use the strategies discussed here to maximize the yields of solid products from batch drying vessels Successfully drying a wet solid in a drying vessel does not complete the operation — the dry solids must be removed from the vessel. This step often presents challenges, because it can be difficult to fully empty drying vessels when leftover solid material remains on the interior surfaces. For batch drying processes where the residues can be dissolved into the subsequent drying run, the problem of incomplete emptying may not be particularly acute. However, for processes where the solid residues must be rinsed out of the vessel’s interior prior to the next drying batch, and the rinse is lost, maximizing the yield of the dryer is of great importance. This article provides information on measures that improve and maximize the yield in batch drying processes for fine chemicals and active pharmaceutical ingredients (APIs). Batch drying processes In most liquid-solid-separation processes, thermal evaporation (in a vacuum contact dryer) is often the follow up step to mechanical dewatering, in order to achieve the best “dryness” result. During any drying process, all additives and solvents must be removed from the solid materials…