Abstract:
The aim of this study is to design, construct and test a fuel processor prototype for catalyst performance studies under steady-state and dynamic operation conditions. The propane fuel processor consisted of a main oven with three vertical ovens inside. In those units, three reactions, oxidative steam reforming (OSR), water gas shift (WGS) and preferential oxidation (PROX) were conducted. The system can be used to perform up to three serial reactions, like OSR, WGS and PROX or HTWGS, LTWGS and PROX. Additionally, the design of the system allowed keeping water vaporized in the system with the help of the main oven, the possibility of addition of new streams enabling either parallel operation of the reactions and/or simultaneous catalyst reduction steps. In this work, OSR and WGS reactions were performed in a serial fashion over 0.2%Pt-10%Ni/γ-Al2O3 and 2%Au-1%Re/ZrO2 catalysts, respectively. Oxygen/propane/steam flow rates and reaction temperatures were the experimental parameters used during the steady state and dynamic tests. Six sets of experiments, each including two ramp type perturbations, were performed during this study. Propane and oxygen conversions of nearly 100% were achieved in all experiments. Highest achieved selectivity (H2/CO) was 37 for OSR temperature of 673 K and WGS temperature of 573 K, S/C ratio of 3 and C/O2 ratio of 2.7 and for a total inflow of 100 ml/min, where the perturbation variable was steam flow rate. The test also showed the lowest CO concentration obtained at the WGS outlet as 0.57%. On line and real time analysis by a mass spectrometer allowed performing dynamic response tests. In inertia tests, steady state profiles were achieved at 36 minutes. In dynamic response tests, S-type steady state profiles were achieved for the given perturbations. Oxygen and propane ramp type perturbation tests showed better steady state profiles than that of the water tests with the required 1 hour 20 minutes for reaching steady state.
