Abstract:
Methods are provided for synthesizing ZSM-58 crystals with an improved morphology and/or an improved size distribution. By controlling the conditions during synthesis of the ZSM-58 crystals, crystals of a useful size with a narrow size distribution can be generated. Steaming the H-form DDR framework type crystals at a temperature from 426±° C. to 1100±° C. for a time period from about 30 minutes to about 48 hours can attain one or more of the following properties: a CH4 diffusivity of no more than 95% of the CH4 diffusivity of the unsteamed H-form DDR framework type crystals; an N2 BET surface area from 85% to 110% of the surface area of unsteamed H-form DDR framework type crystals; and an equilibrium CO2 sorption capacity from 80% to 105% of the equilibrium CO2 sorption capacity of unsteamed H-form DDR framework type crystals.
Abstract:
The present invention relates to a pressure-temperature swing adsorption process wherein gaseous components that have been adsorbed can be recovered from the adsorbent bed at elevated pressures. In particular, the present invention relates to a pressure-temperature swing adsorption process for the separation of C2+ hydrocarbons (hydrocarbons with at least 2 carbon atoms) from natural gas streams to obtain a high purity methane product stream. In more preferred embodiments of the present processes, the processes may be used to obtain multiple, high purity hydrocarbon product streams from natural gas stream feeds resulting in a chromatographic-like fractionation with recovery of high purity individual gaseous component streams.
Abstract:
Asymmetric membrane structures are provided that are suitable for various types of separations, such as separations by reverse osmosis. Methods for making an asymmetric membrane structure are also provided. The membrane structure can include at least one polymer layer. Pyrolysis can be used to convert the polymer layer to a porous carbon structure with a higher ratio of carbon to hydrogen.
Abstract:
Asymmetric membrane structures are provided that are suitable for various types of separations, such as separations by reverse osmosis. Methods for making an asymmetric membrane structure are also provided. The membrane structure can include at least one polymer layer. Pyrolysis can be used to convert the polymer layer to a porous carbon structure with a higher ratio of carbon to hydrogen.