Abstract: In fractionating a gaseous mixture, e.g. an acid gas and hydrocarbon, in a column wherein, during distillation, components of the gaseous mixture tend to form a substantially azeotropic mixture, or at least one of the components of the gaseous mixture tends to freeze out, withdrawing a side stream fluid from the column during fractionation, and separating said side stream fluid, e.g. by membranes or scrubbing, so as to remove preferentially at least a portion of one of the components of the substantially azeotropic mixture, or of the at least one of the components tending to freeze out, and recycling resultant depleted side stream to said fractionating column.

Abstract: For the separation of fluid mixtures, the mixture is cooled sufficiently to form more than two phases of differing densities, and especially two liquid phases. The individual phases are then separated in correspondence with their densities. The process is especially applicable as a pretreatment in the absorptive removal of sour gases from gaseous mixtures as well as in the regeneration of a solvent loaded with gaseous impurities.

Abstract: In fractionating a gaseous mixture, e.g. an acid gas and hydrocarbon, in a column wherein, during distillation, components of the gaseous mixture tend to form a substantially azeotropic mixture, or at least one of the components of the gaseous mixture tends to freeze out, withdrawing a side stream fluid from the column during fractionation, and separating said side stream fluid, e.g. by membranes or scrubbing, so as to remove preferentially at least a portion of one of the components of the substantially azeotropic mixture, or of at least one of the components tending to freeze out, and recycling resultant depleted side stream to said fractionating column.

Abstract: In the separation of a more readily diffusing component from a gaseous mixture containing same and at least one less readily diffusing component, by diffusion via semipermeable membranes, a gas is fed to the passage side of the membranes, this gas being essentially free of ingredients of the more readily diffusing component, or in the alternative, such a gas also exhibiting a substantially higher rate of diffusion than the more readily diffusing component is fed to the barrier side.

Abstract: A mixture of gases containing hydrogen and at least one further component, for example nitrogen and argon, is enriched in hydrogen in a separation stage by adsorption, or cooling and partial condensation and/or rectification and/or scrubbing. Upstream of this separation stage, at least part of the hydrogen is separated by membrane diffusion, thereby resulting in a highly improved process as compared to using either the separation stage or membrane diffusion alone, especially in connection with gaseous mixtures having components which are to be used at high pressures, e.g., a purge gas from an ammonia synthesis gas process.