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Gas Phase Separations \ Hydrogen Separations and Purification \
Carbon Molecular Sieve Membranes
Membrane Performance
Membrane Productivity... Membrane hydrogen permeances ranging from 0.5 to >2 m3/m2/hr/bar at 200-250°C have been demonstrated depending upon the selectivity desired. Selectivities for H2 to CH4 are 50 to >100 at temperatures in of 200 to 250°C. Typical performance of our carbon molecular sieve hydrogen selective membranes is 1.5 m3/m2/hr/bar H2 at the H2/CH4 of 100 at 220°C.
Membrane Poisoning Resistance... Productivity losses due to organic vapor condensation in the nanopores of the active membrane layer presents a unique potential problem for this application. The simplest way to overcome this problem is to operate at high temperatures. The table below shows the H2 permeance of our membrane at 80 and 180°C before and after exposure for eight hours to a stream of helium saturated with hexane at 40°C (~150,000 ppmv hexane). Hence, the membrane performance is stable at high operating temperatures in the presence of very high concentrations of condensable organic vapors making the membrane ideal for hydrogen recovery from refinery off-gas.
Field Test Experience... Our carbon molecular sieve based inorganic membranes have been field tested using a slip stream from a refinery H2 recovery from VGO hydrocracker purge stream as shown in the figures below. Hydrogen was enriched to ~99.7 from ~90% in the presence of a stream containing ~25 % H2S, and >10% C3+.
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