Analysis of the Impact of Gas-Phase Chemistry in Adiabatic CPO Reactors by Axially Resolved Measurements

This chapter focuses on the contribution that the in situ probing of temperature and concentration profiles in high-temperature and short contact time partial oxidation processes has given to the understanding of the interplay between homogeneous and heterogeneous chemistry. Experimental evidence was collected in our laboratory on the gas-phase conversion of C2+fuels in adiabatic CPO reformers. The formation of short-chain hydrocarbons can promote the syngas performance, since the fed fuel is partly transformed into highly reactive species which further react on the surface producing CO and H2; however, short olefins are soot/coke precursors and the surface condensation or breakthrough of such species is highly undesired. The experience from CPO reactors and other similar processes allows to understand the effects that pressure and dilution, the nature of the fuel and of the catalyst, and heat dispersions across the reactor have on the final fate of the cracking intermediates. The possibility to tune the relative contributions of the gas-phase and the surface chemistry in order to limit the catalyst hot spot temperature is also discussed.