Batch vacuum crystallizers are used for cases requiring very low operating temperatures achieved only by very high vacuum, and for those applications involving relatively small amounts of material,or when the material being processed must be handled on less than a continuous basis, it is often convenient and economical.

Where the material is cooled through a very wide range and / or to a final temperature which requires a very high vacuum, a large ejector or booster is utilized to compress the vapor to a pressure high enough for condensation with available cooling water . In such cases, the batch vacuum crystallizer steam economy is achieved by multiple stage continuous equipment of five or more stages.