A process is described for recovery of a more selectively adsorbed key component from a gas mixture containing the key component and one or more less selectively adsorbed secondary components using vacuum swing adsorption. The process minimizes capital costs by reducing or eliminating gas storage vessels and reduces power requirements by operating without a feed compressor or elevated pressure feed, whereby feed is induced at least in part by vacuum conditions achieved by pressure equalization between parallel adsorption beds. Alternatively, at least a minor amount of less selectively adsorbed secondary component roduct can be recovered.