Facile Regeneration vitreous microfibrous entrapped supported ZnO sorbent with high contacting efficiency for bulk H2S removal from reformate streams in fuel cell applications

In this study, a microfibrous carrier consisting of 3vol% of 8 m (dia.) glass fibers is utilized to entrap 45 vol% of 150-250 m (dia.) SiO2 support particulates. ZnO is then nano-dispersed onto the support by impregnation at the loading of 17 wt%. At equivalent bed volumes, ZnO/SiO2 entrapped materials provide 2-fold longer breakthrough times for H2S (with a 67% reduction in sorbent loading) compared to packed beds of 1-2 mm commercial extrudates. 5-log reductions in H2S concentration with up to 75% ZnO utilization at breakthrough are achieved. H2S concentrations from 60 to 2,000 ppmv can be reduced to as little as 0.6 ppmv at 400 C in 30% H2O at a face velocity of 1.7cm/s for layers as thin as 1.0 mm. At 500-600C, ZnO/SiO2 entrapped materials provide much higher regenerability in air than 1-2mm commercial extrudates do. The use of glass fibers permits greater than 50 regeneration cycles.