Abstract: The disclosed chemical process is carried out in a series of vertically stacked conversion (e.g. fermentation) zones which are subdivided into movable segments. Flow from one zone to another is gravity-induced. A portion of the production medium is recirculated to an upper zone, e.g. the uppermost zone, and metabolites are withdrawn from the zones. Useful metabolites include organic liquids such as alkanols made from fermentation of carbohydrate.In apparatus (10) especially suited to the process: A generally vertically disposed fermentation tower (11) defines a generally vertically extending space containing the vertically arranged zones (15a-15h). A typical zone, e.g. zone (15c) has a floor (65c) having a drain opening (165c) for the continuous discharge by gravity of partially converted feedstock to the next lower zone (15d). Each zone (e.g. 15c) is subdivided into continuously movable segments by movable partitions (157c) for advancing the feedstock in the zone toward the drain opening.

Abstract: The disclosed continuously operated apparatus (10) is suitable for a variety of chemical processes, including enzymatic conversion of substrates to, for example, organic liquids such as alkanols. In this apparatus (10):A generally vertically disposed fermentation tower (11) defines a generally vertically extending space containing a plurality of vertically arranged, tray-like zones (15a-15h) for the temporary retention, continuous receiving, and continuous gravity discharge of a feedstock. A typical zone, e.g. zone (15c) has a generally horizontal floor (65c) having a drain opening (165c) for the continuous discharge by gravity of partially converted feedstock to the next lower zone (15d). Each zone (e.g. 15c) is further divided into continuously movable segments by movable partitions (157c) for advancing the fermentable feedstock in said fermentation zone toward the drain opening.