A Study on Cetane on Demand Technology Part 1 - Development of Fuel Reformer to Improve Fuel Ignitability

The integration of low-octane gasoline with a compression ignition combustion system has been proposed as a strategy to reduce Well-to-Wheel CO2 emissions from automobiles using petroleum-based fuel. In the current situation where low-octane gasoline is not widely available in the market, onboard reforming of commercial gasoline to increase the cetane number (lower the octane number) allows for compression ignition combustion even with commercial gasoline. This requires “Cetane on Demand” technology, which enables compression ignition combustion with both commercial gasoline and low-octane gasoline. It is known that the ignition property of fuel is enhanced when the fuel is oxidized to generate hydroperoxides. Moreover, the use of N-hydroxyphthalimide (NHPI) as a catalyst promotes hydroperoxide generation at low temperatures. The objective of this study is to develop a device that enhances the ignition properties of gasoline through onboard fuel reforming. Initially, from the seven kinds of NHPI-supported solid catalysts, a catalyst appropriate for a flow reactor operating at ambient pressure was selected. The NHPI-supported ZSM-5 catalyst demonstrated the highest performance in hydroperoxide formation under flow reactor conditions. Subsequently, with a focus on onboard reforming, two types of reactors (spiral-type reactor and inner-circulation type reactor) and two methods of air introduction (metal mesh bubbler and mechanical stirring bubbler) to ensure adequate contact between the fuel, air, and solid catalyst were designed and prototyped. The combination of the spiral-type reactor and mechanical stirring air introduction exhibited the best performance in hydroperoxide formation.