Scaling rules have been developed which are able to change the dimension of a pressure swing adsorption plant keeping its main performance constant. Such scaling rules result from a system of algebraic equations which arises by constraining the solution of a fairly general dimensionless mathematical model to be the same in the old and new plant configuration. Different heat and mass transfer mechanisms, purification, and multicomponent bulk separation processes, both isothermal and nonisothermal, have been considered. Furthermore, the influence of different equilibrium isotherms and the main practical limitations have been discussed. The application of these rules shows that column size can be reduced significantly by using smaller particles in shorter beds with rapid cycles.