C4 Hydrocarbon Fraction as a Feedstock for Steam Cracking

Abstract

Due to the market demand of C4 hydrocarbon fraction in recent years, it is often necessary to recycle this fraction back to the steam-cracker, in order to obtain more profitable products. However, the behavior of this feedstock is quite untypical due to the presence of light unsaturated hydrocarbons, which appear in the reactor as reactants and not as products, as in the usual case. The present paper overviews available published information on the behavior of C4 hydrocarbons during pyrolysis and co-pyrolysis with other compounds. The scission and other pyrolysis reaction mechanisms of C4 hydrocarbons are described in detail. Moreover, we report on how the behavior of C4 hydrocarbons is influenced by the co‑pyrolyzed hydrocarbon and vice versa, regarding the conversion and pyrolysis product selectivity. Special attention is paid to unsaturated hydrocarbons as they influence the reactivity and product distribution of the pyrolyzed feedstock most.