TECHNOLOGY FOCUS - CHEMICAL ENGINEERING - Preferred process: At all times in the process an average of at least two of the beds are being simultaneously regenerated by simultaneously providing off-gas from a feed end of each of the two beds to an off-gas line.Each of the four steps comprises a depressurizing equalization phase spanning about 1/20 of a total cycle time of the process and a repressurization phase 'R' spanning about 1/20 of the total cycle time.The process may be represented by a cycle chart in which:(1) A is adsorption;(2) 1 is providing gas for a first step of pressure equalization;(3) 2 is providing gas for a second step of pressure equalization;(4) 3 is providing gas for a third step of pressure equalization;(5) 4 is providing gas for a fourth step of pressure equalization;(6) P is providing purge gas;(7) B is countercurrent blow down;(8) G is counter-current purge;(9) I is idle;(10) 4' is receiving gas for the fourth step of pressure equalization;(11) 3' is receiving gas for the third step of pressure equalization;(12) 2' is receiving gas for the second step of pressure equalization;(13) 1' is receiving gas for the first step of pressure equalization and simultaneously receiving product gas for repressurization; and(14) R is repressurizing with product gas.The apparatus has ten beds and four pressure equalizations per bed are performed throughout the process.The product gas is preferably hydrogen and the feed gas comprises hydrogen, and at least one of methane, carbon dioxide, carbon monoxide, nitrogen and/or water vapor.The feed gas is obtained by:(1) steam reforming of hydrocarbons; or(2) partial oxidation of hydrocarbons.Partial oxidation preferably occurs in the presence of one or more catalysts and the oxygen used in the partial oxidation is provided by an ion transport membrane which may be integrated with a reactor in which partial oxidation occurs.At least one repressurizing equalization step overlaps in time with the pressure augmentation step. or may overlap in time with at least one of counter-current repressurization by the product gas and co-current repressurization by the feed gas.