Abstract: Bayesian recursive estimation is used to analyze performance parameters of a membrane separation system based on historical operational data of a membrane system. Bayesian estimation considers historical data over prior time intervals to predict future membrane separation performance to avoid unexpected downtime and unanticipated maintenance. A set of state variables used for modeling performance is used with a degradation model of to anticipate performance changes and maintenance based on measured properties of permeate, non-permeate, and feed flows.

Abstract: Membranes used in membrane separation technologies change over time due to changes in physical characteristics of the membrane. Predicting remaining useful lifetime of a membrane is performed by fitting an evolution model of the membrane to real-time performance characteristics recorded for the membrane and by comparing later performance characteristics of the membrane to the evolution model. Updating an evolution model during membrane operation improves estimates of remaining useful membrane lifetime and allows for accurate estimates of estimated membrane end-of-life.

Abstract: Bayesian recursive estimation is used to analyze performance parameters of a membrane separation system based on historical operational data of a membrane system. Bayesian estimation considers historical data over prior time intervals to predict future membrane separation performance to avoid unexpected downtime and unanticipated maintenance. A set of state variables used for modeling performance is used with a degradation model of to anticipate performance changes and maintenance based on measured properties of permeate, non-permeate, and feed flows.

Abstract: A membrane filter element includes at least two cylindrical-shaped, fiber bundles, one of the fiber bundles containing first fibers fabricated to provide a selected first gas selectivity, a selected first gas permeability, or a selected first gas selectivity and permeability performance and arranged so a first gas permeate exits the membrane element; another of the fiber bundles containing second fibers fabricated to provide a selected second, different gas selectivity, a selected second different gas permeability, or a selected second gas selectivity and permeability performance and arranged so a second different gas permeate exits the membrane element. The different performance characteristics can reduce the number of membrane elements required for gas separation and to improve gas separation performance due to changing gas composition as the gas travels through the membrane element.

Abstract: A natural gas stream is passed through a single membrane element that is fabricated with two or more distinct types of membrane fibers. The membrane fibers have different characteristics in order to reduce the number of membrane elements required for gas separation and to improve gas separation performance due to changing gas composition because of permeation as the gas travels through the membrane element.

Abstract: A natural gas stream is passed through a single membrane element that is fabricated with two or more distinct types of membrane fibers. The membrane fibers have different characteristics in order to reduce the number of membrane elements required for gas separation and to improve gas separation performance due to changing gas composition because of permeation as the gas travels through the membrane element.

Abstract: A separation membrane useful for gas separation, particularly separation of C.sub.2+ hydrocarbons from natural gas. The invention encompasses the membrane itself, methods of making it and processes for using it. The membrane comprises a polymer having repeating units of a hydrocarbon-based, disubstituted polyacetylene, having the general formula: ##STR1## wherein R.sub.1 is chosen from the group consisting of C.sub.1 -C.sub.4 alkyl and phenyl, and wherein R.sub.2 is chosen from the group consisting of hydrogen and phenyl. In the most preferred embodiment, the membrane comprises poly(4-methyl-2-pentyne) ?PMP!. The membrane exhibits good chemical resistance and has super-glassy properties with regard to separating certain large, condensable permeant species from smaller, less-condensable permeant species. The membranes may also be useful in other fluid separations.