Direct decomposition of hydrogen sulfide through microwave-induced discharge of graphitized bio-char

Abstract

Direct decomposition of hydrogen sulfide (H2S) can be used to obtain high-purity hydrogen, thereby avoiding the waste of hydrogen resources by traditional Claus process. Microwave-induced discharge with spherical bio-char for H2S decomposition is proposed. The bio-char was treated by graphitization modification in presence of microwave heating and iron additive. The influences of graphitization parameters including iron loading and microwave irradiation time on the bio-char graphitization degree were studied. Subsequently, the modified bio-char was applied to induce microwave discharge, and the effects of graphitization parameters on discharge performance were discussed. Lastly, the attention was paid to investigate catalytic effect of microwave-induced discharge with the modified bio-char for H2S decomposition. The results showed the best graphitization degree of bio-char was achieved at iron loading of 6 mmol/g and microwave irradiation time of 60 min. The improvement of bio-char graphitization degree enhanced discharge intensity, thus promoting bed temperature. Microwave discharge exhibited a favorable catalytic effect on H2S decomposition, with initial and ending conversions at 97.4% and 83.2% in a two-hour test, respectively, because of synergistic effect of microwave discharge effect, microwave thermal effect and catalytic activity of the modified bio-char.