ABSTRACT
Hydrocracking combines hydrotreating and catalytic cracking in a single process. It can be applied to a wide range of feed materials but is mainly used for refining of vacuum gas oil to produce lighter and more isomerized products with good cold flow properties. Hydrocracking technology makes used of fixed bed reactors operated as trickle flow reactors. The extent of hydrotreating and hydrocracking determines hydrogen consumption. In the refining literature hydrocracking is sometimes used as an inclusive term that includes both hydrocracking and residue hydroconversion. The most common refinery application of hydrocracking technology is for the conversion of atmospheric residue and vacuum gas oil fractions to lighter products. The hydrocracking reactor(s) is operated at conditions that are selected to meet the refining objectives. The reactor effluent goes through heat exchangers to a high-pressure separator, where the hydrogen-rich gases are separated and recycled to the first stage for mixing with both makeup hydrogen and fresh feed.
