Investigation of H2 staging effects on CO conversion and product distribution for Fischer-Tropsch synthesis in a structured microchannel reactor

The effect of H-2 staging for Fischer-Tropsch synthesis over a 20 wt% CO/SiO2 catalyst in a 200 ILL wall-coated channel microreactor was investigated. Some pre-experimental modeling was developed from a modified pseudo-homogeneous ID reactor model using a pre-established rate form for CO consumption. The predicted CO conversion levels attained for various discrete staging policies were investigated and the results were used as a pre-selection tool. It was used to design a H-2 Staged reactor with three equally spaced injection ports. The experimental set-up was used to get conversion and product distribution data for various H-2 distribution policies. The experimental conversions were in good agreement with the modeling. The tuning of H-2 flow pattern over the three ports lowered the CO conversion and increased mainly C-5-C-9 selectivity. Once combined, these effects allowed to half the C-1-C-4 yield without dramatically reducing the overall C5+ yield allowing a smarter use of H-2. A non-uniform increasing staging policy gave the best product distribution for C5+ increased production at 0.1 MPa and 180 degrees C. (C) 2007 Elsevier B.V. All rights reserved.