Microchannel reactors are compact reactors that have channels with diameters in the millimetre range. These small channels dissipate heat more quickly than conventional reactors with larger channel diameters in the 2.5 – 10 cm (1 – 4 inch) range, so more active catalysts can be used, such as those developed by Oxford Catalysts. Mass and heat transfer limitations reduce the efficiency of the large conventional reactors used for Fischer-Tropsch and Steam Methane Reforming reactions and hydroprocessing. The use of microchannel processing makes it possible to greatly intensify chemical reactions enabling them to occur at rates 10 to 1000 times faster than in conventional systems.
Microchannel Fischer-Tropsch reactors, developed by Velocys and using a new highly active FT catalyst developed by Oxford Catalysts, are now available for the small scale distributed production of fuels. These reactors exhibit conversion efficiencies in the range of 70% per pass, and are designed for economical production on a small scale. The FT process using microchannel reactors operates economically at 1,000 bpd (or more). In contrast, conventional FT plants are designed to work at minimum capacities of 5,000 bpd, and function well and economically at capacities of 30,000 bpd or higher. They typically exhibit conversion efficiencies in the range of 50% or less per pass. Microchannels have a smaller footprint, can be scaled up or down more flexibly as they can be 'numbered up', and have efficiencies superior to those achievable using conventional process technology.
Microchannel reactors therefore have the potential to unlock the distributed production of fuels and other materials on a small, decentralised scale.