Influência da relação C/N na produção de hidrogênio em reator anaeróbio de leito fixo / Influence of the carbon/nitrogen ratio on the hydrogen production in a fixed-bed anaerobic reactor

AUTOR(ES)
DATA DE PUBLICAÇÃO

2010

RESUMO

This study evaluated the effect of the carbon/nitrogen (C/N) ratio on the hydrogen production from a sucrose-based synthetic wastewater. Up-flow fixed-bed anaerobic reactors with recycled low-density polyethylene for biomass attachment, were operated at 25ºC and with a 2 hours time of hydraulic detention. Several C/Nrelationship were studied (40, 90, 140 and 190), using sucrose and urea as carbon and nitrogen sources, respectively. The average value of the hydrogen productivity were 0,6 mol-H IND.2/mol-suc, 1,3 mol-H IND.2/mol-suc, 2,7 mol-H IND.2/mol-suc e 1,7 mol-H IND.2/mol-suc they were reached when the reactors were operated with C/Nof 40, 90, 140 and 190, respectively. It was found an optimal value for C/Nof 137, which would result in productivity of 3,5 mol-H IND.2/mol-suc, an amount equal to that achieved in the C/Nrelationship of 140. Biogas produced was composed of H IND.2and CO IND.2, with average H IND.2content 53%, 49%, 61% and 52% for C/Nof 40, 90, 140 e 190, respectively. The mainly intermediary products during H IND.2fermentation were similar for all the C/Nratios, being specially detected acetic acid, butyric acid and ethanol. Under excess of nitrogen the biomass growth is higher with negative effects on hydrogen production while deprivation of nitrogen permits the control of biomass growth and results in higher hydrogen productivity. During the experiments it was been observed decline in the biogas production, probably because of the action of the hydrogen-oxidizing bacteria.

ASSUNTO(S)

sacarose sucrose fermentation hydrogen production relação carbono/nitrogênio fermentação produção de hidrogênio carbon/nitrogen ratio

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