ABSTRACT
Natural gas and crude oil are primary feedstocks, and continue to be, the main sources of secondary feedstocks for the production of petrochemicals. For example, methane from natural gas as well as other low-boiling (low molecular weight) hydrocarbon derivatives is recovered for use as feedstocks for the production of olefin derivatives and diolefin derivatives. In addition, the gaseous constituents from crude oil (associated natural gas) as well as refinery gases from different crude oil processing schemes—such as cracking and reforming processes (Parkash, 2003; Gary et al., 2007; Speight, 2014a; Hsu and Robinson, 2017; Speight, 2017)—are important sources for olefin derivatives. Paraffin hydrocarbon derivatives (i.e., hydrocarbon derivatives with the general formula CnH2n+2) that are used for producing petrochemical products range from methane (CH4) to the higher molecular weight hydrocarbon derivatives that exist in various distillate fractions such as naphtha, kerosene, and gas oil as well as the nonvolatile residua (resids, residues) (Table 6.1). The proportion of pure hydrocarbon derivatives in residua is typically at a low level and most of the constituents of residua also contain heteroatoms (nitrogen, oxygen, sulfur, and metals) in various molecular locations (Speight, 2014a).
