| Short contact time catalytic reactors represent an alternative to existing technologies because of their potential as small sized, high throughput processors. However, these reactors are often characterized by large gradients in temperature and concentration, as well as spatial distribution of chemical reactions, which demands the use of advanced methods for studying them. Two such systems are studied in this thesis with an emphasis on understanding how co-feeding secondary reactants or poisons can help elucidate the chemical and physical phenomena inherent to the system. Common to both studies is the use of the capillary sampling technique, which allows for determination of spatial profiles of composition and temperature; this technique is described and analyzed as well. The first system explored is the catalytic partial oxidation of methane, wherein steam and CO2 addition provide insight to the relative activities of water gas shift and reforming reactions. Co-feed allows for a simple adjustment of the H2/CO ratio; however, modifying Rh catalysts with Ce and washcoat relieves the limitation in the water gas shift rate with unmodified Rh that results in non-equilibrated products. Second, the partial oxidation of ethane to syngas and ethylene over Rh and Pt catalysts is examined. Hydrogen co-feed and poisoning by H2S help to elucidate the roles of the catalyst that produce distinct product distributions for the two metals. Namely, the preferential H2 oxidation and lack of steam reforming activity over Pt largely accounts for the high ethylene selectivity. |
