Formation of HCN and NH_3 during the Reforming of Quinoline with Steam in a Fluidized-bed Reactor

摘要

Formation of HCN and NH_3 during the pyrolysis and reforming of quinoline with steam was investigated using a novel two-stage fluidized-bed/fixed-bed reactor. The reactions via soot formation on a solid surface (e.g., sand) provide important routes for the conversion of quinoline-N into HCN and NH_3 during pyrolysis and steam reforming at temperatures below 850℃. The main route for the HCN formation is the breakdown of the N-containing intermediates as the intermediates undergo cracking and polymerization reactions to form soot. The subsequent hydrogenation of soot-N is an important source for NH_3 formation when the temperature is 850℃ or lower. The gasification of soot in steam can also account for a small portion of the observed HCN. Above 850℃, the hydrolysis of HCN into NH_3 alters the final yields of HCN and NH_3 during the reforming of quinoline with steam. During the reforming of quinoline with steam at 800℃, the addition of coal ash, simulating the conditions in a coal/biomass gasifier, remarkably enhances the hydrolysis of HCN into NH_3, although the activity of the ash diminished rapidly with time due to possible changes in the physicochemical forms of active species in ash.