Microchannel reactor for Fischer–Tropsch synthesis: Adaptation of a commercial unit for testing microchannel blocks

This paper reports developments in adapting a catalytic test unit (PID-Micromeritics Microactivity Reference) for testing microchannel cross-flow blocks during Fischer–Tropsch Synthesis (FTS). The unit was equipped with an additional cooling line with water pressurized to prevent boiling at the reaction temperature. A container in the water line partially filled with air was necessary in order to buffer pressure changes due to water dilation, thus enabling good temperature and pressure control. Microchannel blocks were tested in a housing including headers sealed with graphite gaskets allowing excellent sealing (less than 0.01 mg of gas per second per linear meter of gasket: <L0.01). Catalytic results from two microchannel blocks having different catalyst coating thickness demonstrated the good selectivity for C5+ that can be achieved during FTS due to the excellent temperature control of the microchannel technology. Catalyst coating thickness influences the selectivity for both C5+ and olefin/paraffin ratio and discourages the use of coatings that are too thick.