Use of a swirling flow to mechanically regenerate catalysts after methane decomposition

Abstract

A new device is proposed to regenerate catalysts after hydrogen production via methane decomposition. Because carbon deposition inhibits catalytic reactions, carbon removal is indispensable for continuous hydrogen production. This device generated a swirling flow by gas supplied at the top and bottom along the inner surface of a tube. The swirling flow rotated the catalyst particles in the tube. Shear stresses on the particles caused by inter-particle and particle-wall impacts led to attrition. Carbon was mechanically removed from the particles by attrition and was elutriated with the flue gas. Ten cycles of methane decomposition and catalyst regeneration were performed using reduced ilmenite as a catalyst. Carbon was clearly removed by catalyst regeneration. Stable regeneration was confirmed by examination of weight changes of the particles caused by carbon deposition and removal during the cycles. Hydrogen production increased by 10% during the cycles than during continuous methane decomposition for 4 h.