Published December 2023
Product slates of crude oil refineries are expected to shift gradually toward more base chemicals feedstock at the expense of transportation fuels. One of the options to increase petrochemical naphtha production is to hydrocrack various refinery distillates in the diesel boiling range into naphtha. These streams include straight-run diesel, fluid catalytic cracker light cycle oil, hydrocracker light gasoil and coker light gasoil. The technology for producing naphtha from diesel is not new and is closely related to fixed-bed gasoil hydrocracking technology to produce middle distillates, namely diesel and kerosene. These so-called distillate hydrocrackers have been used mostly in the United States where gasoline demand far outstrips diesel demand for use as transportation fuel. In the last few years, several new diesel hydrocracker units have been designed for petrochemical naphtha production in the mainland Chinese crude oil to chemicals (COTC) complexes. These complexes convert a much higher fraction of feed crude to chemicals feedstock than traditional fuels refineries do.
This Process Economics Program (PEP) review presents a brief status of the global and US diesel and light distillate hydrocracker capacity trends. A detailed review of the diesel hydrocracker technology is also presented which includes the process configuration, operating conditions, catalyst selection and chemistry.
PEP’s design of a 60,000 b/d (2.9 million metric tons per year) diesel hydrocracker operating in full conversion to heavy naphtha and lighter products is presented. The design is for a single-stage fixed-bed hydrocracker with 65% single pass conversion with full recycle of the unconverted diesel, followed by separations and product fractionation sections. The design is based on generic diesel hydrocracking technology developed from patent literature and publications made by various technology developers and PEP in-house databases. We provide our basis of design, detailed process description, a HYSYS® simulation-based heat and material balance, sized equipment list, inside battery limits (ISBL), outside battery limits or offsites (OSBL) and total fixed capital cost estimates. Production cost evaluation is given for the main heavy naphtha product from the unit. The evaluation is developed for a US Gulf Coast (USGC) location and can be extrapolated to several other locations around the globe.