Formation of HCN and NH3 during the Reforming of Quinoline with Steam in a Fluidized-bed Reactor

Abstract

Formation of HCN and NH3 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 NH3 during pyrolysis and steam reforming at temperatures below 850 °C. 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 NH3 formation when the temperature is 850 °C or lower. The gasification of soot in steam can also account for a small portion of the observed HCN. Above 850 °C, the hydrolysis of HCN into NH3 alters the final yields of HCN and NH3 during the reforming of quinoline with steam. During the reforming of quinoline with steam at 800 °C, the addition of coal ash, simulating the conditions in a coal/biomass gasifier, remarkably enhances the hydrolysis of HCN into NH3, although the activity of the ash diminished rapidly with time due to possible changes in the physicochemical forms of active species in ash.