Reactor Vapors Condensers

Heat Exchangers For

Condensers Above the Batch Reactor

A reactor vapor condenser serves a vessel whose vapor load changes through every batch. During heat-up it sees almost nothing, at total reflux it returns everything to the reactor, during a distillation or solvent swap it sends condensate to a receiver, and at the end of the batch it may run under deep vacuum to strip the last solvent. The same surface must handle all of those modes, plus the exotherm case where reflux cooling is part of the reactor's safety basis.

A vertical Fixed Tubesheet unit mounted above or beside the reactor is the standard arrangement. In knock-back service the vapor rises through the tubes and the condensate runs back down against it; in a downflow arrangement vapor and condensate travel together to a receiver. A Welded Plate unit saves headroom and suits clean, steady distillation steps, but it does not tolerate countercurrent reflux well and is harder to inspect, so it is usually a second condenser rather than the one sitting on the reactor nozzle.

The size that matters is rarely the normal-reflux load. It is the maximum boil-up the jacket can deliver plus any reaction heat, and for a reactive system the runaway or relief case defined in the process hazard analysis. Bring that number, along with the solvent list, the lowest vacuum used and the coolant available.