Chapter 9. Batch Distillation

Continuous distillation is a thermodynamically efficient method of producing large amounts of material of constant composition. When small amounts of material or varying product compositions are required, batch distillation has several advantages. In batch distillation a charge of feed is loaded into the reboiler, the steam is turned on, and after a short startup period, product can be withdrawn from the top of the column. When the distillation is finished, the heat is shut off and the material left in the reboiler is removed. Then a new batch can be started. Usually the distillate is the desired product.

Batch distillation is a much older process than continuous distillation. Mesopotamian clay distillation pots have been dated to around 3500 BCE (RT, 2007), and alchemists in Alexandria used simple batch retorts in the first century A.D. (Davies, 1980). Batch distillation was developed to concentrate alcohol by Arab alchemists around 700 A.D. (Vallee, 1998). It was adopted in Western Europe, and the first known book on the subject was Hieronymus Brunschwig’s Liber de arte distillandi, published in Latin in the early 1500s. This book remained a standard pharmaceutical and medical text for more than a century. The first distillation book written for a literate but not scholarly community was Walter Ryff’s Das New gross Distillier Buch published in German in 1545 (Stanwood, 2005). This book included a “listing of distilling apparatus, techniques, and the plants, animals, and minerals able to be distilled for human pharmaceutical use.” Advances in batch distillation have been associated with its use to distill alcohol, pharmaceuticals, coal oil, petroleum oil, and fine chemicals.