Abstract
BACKGROUNDMembranes are the core and the main limitation of pervaporation. For example, in certain cases (more often for organic-organic mixtures) a pure product is not attainable as a permeate of a single stage and a series of membrane stages spaced by a condenser is required, making the process economically unacceptable.
RESULTSThis work discusses the use of an alternative approach by exploring the multi-stage-batch-pervaporation (MSBP) unit operation. Here, the permeate obtained after each batch-stage is recycled to the feed tank to increase the permeate product purity in a following stage. The separation of methanol-methyl acetate mixtures was chosen as a case study. Simulations demonstrate how a multi-stage-batch-pervaporation unit is able to meet product purity requirements, by varying the stage-termination condition and the number of stages, employing a single membrane-module and a single condenser. Moreover, a new way to visualize pervaporation separation performance of different membranes is proposed to replace the pervaporation separation index (PSI) analysis.
CONCLUSIONBeing very flexible, the multi-stage-batch-pervaporation unit operation could be of benefit for all small batch productions, even when using medium-low performance membranes. Parts of continuous productions could also be suitable for multi-stage-batch-pervaporation systems. (c) 2015 Society of Chemical Industry