Proceedings of the 1993 DOE/NREL Hydrogen Program Review, 4-6 May 1993, Cocoa Beach, Florida

Abstract

Hydrogen production in cyanobacteria is particularly attractive because t11ese organisms are able to generate their own source of organic substrates using light energy and use water as their ultimate source of reductant. Molecular biology approaches are being applied to understanding and increasing hydrogen production in filamentous strains of cyanobacteria. The soluble hydrogenase structural genes of Anabaena PCC 7120 were not identified by hybridization experiments. Characterization of an Anabaena PCC 7120 DNA fragment identified by hybridization analysis using the soluble hydrogenase gene from Anabaena cy/indrica as a heterologous probe resulted in the identification of the genes for a putative restriction-modification enzyme system of Anabaena PCC 7120. Experiments have continued towards the development of a genetic system for Spiru/ina pacifica. These include (l) the identification of three unique restriction enzymes and (2) PCR amplification of the gene encoding the 16S ribosomal RNA in this strain.

Analysis of an Electrochemical Filter for Removing Carbon Monoxide from Reformate Hydrogen

“…However, this will result in a net consumption of hydrogen (approximately 1.5% for a CO concentration of 1,000 ppm). For an exit CO concentration level of 10 ppm, the hydrogen loss in electrochemical filtering compares favorably with other technologies like PSA (8%) 22 and catalytic methanation (11%). 26 The tradeoff in decreasing the losses between power and hydrogen would need to be analyzed for a particular application.…”

“…But the tolerance level of PEMFC has been improved only to a CO concentration of 100 ppm. 9,[14][15][16][17][18][19][20] In general, CO contamination in H 2 is handled by employment of CO removal techniques such as pressure swing adsorption (PSA), [21][22] or membrane separation, 23 or conversion of CO into methane in catalytic methanation [24][25][26] or carbon dioxide (CO 2 ) in preferential oxidation (PrOx) with air bleed. [7][8]14,[27][28][29][30][31][32][33][34][35][36][37][38][39] However, the consequent increase in cost due to fuel loss, 7 power loss, 40 components and space requirements 41 hampers the utilization of aforementioned techniques for commercially viable systems, especially in portable power applications.…”