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Apparatus and method for simultaneous recovery of hydrogen from water and from hydrocarbons

United States Patent

6,165,438
December 26, 2000
View the Complete Patent at the US Patent & Trademark Office
Los Alamos National Laboratory - Visit the Technology Transfer Division Website
Apparatus and method for simultaneous recovery of hydrogen from water and from hydrocarbon feed material. The feed material is caused to flow over a heated catalyst which fosters the water-gas shift reaction (H.sub.2 O+COH.sub.2 +CO.sub.2) and the methane steam reforming reaction (CH.sub.4 +H.sub.2 O3 H.sub.2 +CO). Both of these reactions proceed only to partial completion. However, by use of a Pd/Ag membrane which is exclusively permeable to hydrogen isotopes in the vicinity of the above reactions and by maintaining a vacuum on the permeate side of the membrane, product hydrogen isotopes are removed and the reactions are caused to proceed further toward completion. A two-stage palladium membrane reactor was tested with a feed composition of 28% CQ.sub.4, 35% Q.sub.2 O (where Q=H, D, or T), and 31% Ar in 31 hours of continuous operation during which 4.5 g of tritium were processed. Decontamination factors were found to increase with decreasing inlet rate. The first stage was observed to have a decontamination factor of approximately 200, while the second stage had a decontamination factor of 2.9.times.10.sup.6. The overall decontamination factor was 5.8.times.10.sup.8. When a Pt/.alpha.-Al.sub.2 O.sub.3 catalyst is employed, decoking could be performed without catalyst degradation. However, by adjusting the carbon to oxygen ratio of the feed material with the addition of oxygen, coking could be altogether avoided.
Willms; R. Scott (Los Alamos, NM), Birdsell; Stephen A. (Los Alamos, NM)
The Regents of the University of California (Los Alamos, NM)
09/ 227,220
January 6, 1999
This invention was made with government support under Contract No. W-7405-ENG-36 awarded by the U.S. Department of Energy to The Regents of the University of California. The government has certain rights in the invention.