H2S cracking to produce H2 through microwave discharge catalysis of graphitized petroleum coke

Abstract

Direct cracking of hydrogen sulfide (H2S) can be used to obtain high purity hydrogen (H2), thus avoiding the waste of hydrogen resources by the traditional Krauss process. Microwave-induced discharge of spherical graphitization petroleum coke (PC) was proposed to solve the problem of low efficiency and high energy consumption of H2S cracking. The PC was prepared by microwave-assisted desulfurization and metal (Fe, Co) catalytic graphitization to obtain better discharge effect. Subsequently, the graphitized PC was applied to induce microwave discharge, and the effects of graphitization parameters on the discharge performance were discussed. Lastly, the attention was concentrated on multi-effects catalytic decoupling and cracking kinetic properties of microwave-induced discharge for H2S cracking. PC with Fe1/Co2 loading exhibited greater graphitization degree (ID/IG = 1.027) (30.7 % than petroleum coke), brought stronger discharge intensity (initial and ending intensity at 4.08 V and 2.73 V in one-hour), and better discharge stability (67 % after one-hour) compared to PC raw coke. H2S cracking through microwave discharge catalysis exhibited a favorable catalytic effect, obtained a complete conversion at the initial stage and remained 95.58 % after one-hour, with H2 yield of 98.1 %. With Fe1/Co2 loading, H2S cracking had the least activated energy, 14.96 kJ/mol, which was the multi-effects of microwave discharge catalysis, thermal-catalysis and Co-catalysis. It was further calculated that discharge-catalysis dominated in H2S cracking, with the highest contribution, followed by Co-catalysis, and thermal-catalysis had the lowest contribution.