A carbon molecular sieve (CMS) membrane having improved separation characteristics for separating olefins from their corresponding paraffins is comprised of carbon with at most trace amounts of sulfur and a transition metal, wherein the transition metal is one or more of a group 4-10 and 12 transition metal. The CMS membrane may be made by pyrolyzing a precursor polymer devoid of sulfur in which the precursor polymer has had a transition metal incorporated into it. The pyrolyzing for the precursor having the transition metal incorporated into it is performed in a nonoxidizing atmosphere and at a heating rate and temperature such that the metal has a valence greater than zero (i.e., not metal bonded) to a valence desirably closer to its maximum valence.

Disclosed herein are carbon molecular sieves and methods of making the same through the pyrolysis of a polymer precursor in the presence of a reactive gas stream including a hydrogen source.

The present invention provides a porous carbon fiber which has an excellent permeation amount and excellent pressure resistance, which is prevented from the occurrence of detachment or cracking at an interface, and which can exhibit excellent properties needed for use as a support for a fluid separation membrane. The present invention is a porous carbon fiber having a bicontinuous porous structure, wherein the average value R.sub.ave of the R value of the outer surface and the R value of the inside is 1.0 or more and 1.8 or less, the absolute value ΔR of the difference between the R value of the outer surface and the R value of the inside is 0.05 or less, and R value is a carbonization progression degree calculated from a Raman spectrum in accordance with the following formula:
R value=(intensity of scattering spectrum at 1360 cm.sup.−1)/(intensity of scattering spectrum at 1600 cm.sup.−1).

The invention is an improved method of making an improved carbon molecular sieve (CMS) membrane in which a precursor polymer (e.g., polyimide) is pyrolyzed at a pyrolysis temperature to form a CMS membrane that is cooled to ambient temperature (about 40° C. or 30° C. to about 20° C.). The CMS membrane is then reheated to a reheating temperature of at least 250° C. to 400° C. to form the improved CMS membrane. The CMS have a novel microstructure as determined by Raman spectroscopy. The improved CMS membranes have shown an improved combination of selectivity and permeance as well as stability for separating light hydrocarbon gas molecules such as C.sub.1 to C.sub.6 hydrocarbon gases (e.g., methane, ethane, propane, ethylene, propylene, butane, butylene).

A transfer line between the outlet of a steam cracker and the inlet for the quench system has metallic or ceramic inserts having a pore size from about 0.001 to about 0.5 microns inside the line forming a gas tight barrier with the inner surface of the line and having a vent for the resulting gas tight pocket are used to separate H.sub.2, CH.sub.4, CO and CO.sub.2 from cracked gases reducing the load on the down-stream separation train of the steam cracker.

Disclosed herein are porous asymmetric silicon membranes. The membranes are characterized by high structural stability, and as such are useful as anode components in lithium ion batteries.

According to one embodiment, a composition of matter includes: a first system of continuous voids arranged in a three-dimensional matrix; a second system of continuous voids arranged in the three-dimensional matrix; and a nanoporous barrier separating the first system of continuous voids and the second system of continuous voids. The first system of continuous voids and the second system of continuous voids are interwoven but independent so as to form a plurality of channels through the three-dimensional matrix. Corresponding methods for forming the composition of matter are also disclosed.

A carbon molecular sieve (CMS) membrane is made by pyrolyzing a polymeric precursor membrane in a pyrolysis atmosphere containing a sulfur-containing compound.

A method for manufacturing a porous device (10) is described. The method comprises creating (340) a carbon nanomembrane (40) on a top surface (22) of a base material (20) having latent pores (23) and etching (360) the latent pores (23) in the base material (20) to form open pores (24). The porous device (10) can be used as a filtration device.

Disclosed herein are asymmetric multilayer carbon molecular sieve (“CMS”) hollow fiber membranes and processes for preparing the membranes. The processes include simultaneously extruding a core dope containing a polymer and suitable nanoparticles, a sheath dope, and a bore fluid, followed by pyrolysis of the extruded fiber.