Producing Lubes and Fuels
The benefits of hydrocracking when producing feed for lubricant base stocks are well known and utilised in many plants around the world. In most cases, there is a dedicated lube hydrocracker, followed by dewaxing and finishing steps. However, the integration of a hydrocracker devoted primarily to making high-quality fuels (especially ultra-low-sulphur and low-aromatics diesel), as well as excellent feed for a dewaxing/finishing unit, is more unusual. In this dual role, Chevron Lummus Global (CLG) has exploited both process and catalyst to meet process objectives.
CLG’s first innovation is purely process based and allows the refiner to use a single configuration to make a range of base oil qualities while producing superior fuels. CLG’s patented principle is shown in Figure 1, where the configuration can be set up to produce three lube base oil feedstocks while maintaining to a large degree the desired overall conversion level for fuels. Investment to recover each stream for further Isodewaxing/Isofinishing steps can be phased to match market requirements. BPCL’s plant in Mumbai, India, the Bapco/Neste plant in Bahrain and GS-Caltex’s proposed plant in Yosu, Korea, all use this scheme to meet their specific market requirements. While this process is ideal for grass-roots plants desiring both lubes and fuels with utmost flexibility, there are situations where it is used to produce high viscosity index (V.I.) Group III base oil from an existing hydrocracker/dewaxer/ finisher unit.