(152e) Catalytic Shock Tube | AIChE

(152e) Catalytic Shock Tube

Authors 

McLaughlin, N. M. - Presenter, Columbia University


A catalytic shock tube is a new and novel technique to investigate heterogeneous catalytic reactions at very well defined temperatures (up to 1000 K) and pressures (up to 400 psi). Desired temperatures and pressures can be maintained for very specific time ranges, from 0.7 to 20.0 milliseconds. This method incorporates a catalyzed short contact time (SCT) substrate. The combination of a single pulse shock tube with the short contact time reactor enables the study of complete reactions over a catalyst in the absence of transport effects. These conditions initiate reaction in a real environment then abruptly terminate or freeze the reaction sequence. This enables the detection of intermediate chemical species that give insight into the reaction mechanism occurring in the presence of the chosen catalyst. This apparatus can conduct temperature- and pressure-jump relaxation experiments, which is extremely useful in studying reactions that operate near equilibrium. Tests done so far have studied methane oxidation on the surface of SCT ferrous-based reactor impregnated with platinum based catalyst. The reactions studied are complete and partial methane oxidation. Gas phase measurements that have been attained will be discussed in light to what reactions are taking place. To isolate the effects of the screen and the catalyst on the reaction, three types of tests were run: catalyzed screen with combustible gases, un-catalyzed screen with combustible gases, and catalyzed screen with inert gases. The resulting pressure traces show that both the catalyzed screen with inert gas and the un-catalyzed screen with combustible gas behave the same. The reactive mix of the catalyzed screen with combustible gases exhibits different pressure behaviors, holding the pressure longer and displaying an observed kinetics time delay. The shock tube has been prepared for further research using optical techniques, which will be investigated further.