Production of hydrogen from renewable resources. Final subcontract report

This report presents results from an experimental program to investigate the use of a bromination process to produce hydrogen from biomass. Biomass is reacted with bromine and water, forming hydrobromic acid, which is then electrolyzed to form hydrogen and bromine. Bromination reaction tests showed that agitation has essentially no effect on the bromine-wood reaction rate. Also, the reaction rate is independent of the entire range of HBr concentration (34 to 60 wt %) considered as the feed to the electrolysis cell. Some preliminary tests conducted on aerobic sludge indicated that some sludge may contain a fraction very refractory to bromination; however, the major fraction of the sludge reacted rapidly. Studies of the electrolysis of aqueous HBr solutions showed that an IR-free working voltage of about 0.6 V is attainable (less than one-third the voltage required for electrolysis of water). The effect of platinum catalyst loading on the overvoltage of the graphite negative electrode was measured using a 47.5 wt % HBr solution at 25/sup 0/C; the optium Pt loading factor was approximately 0.5 mg/cm/sup 2/. An engineering and economic anlaysis was made of this process for a plant with an output of 10/sup 7/ scf per day of H/sub 2/. more » The unit cost of H/sub 2/ from the process was estimated to be $18.20/10/sup 6/ Btu in 1979 dollars. In addition, an overall energy efficiency for the process was estimated to be 49%. 31 references, 21 figures, 10 tables. « less