Diploma Thesis Defense by Mrs Konstantina Tsatsalidi
Thesis Title: «Effect of the nature of the support, the metallic phase and the size of metal particles on the catalytic performance for the reaction of steam reforming of propane»
Thursday 17 September 2020, at: 11:00, Venue: https://tuc-gr.zoom.us/j/96854460838?pwd=blFLbVlLMkN6TlFvN3JPbUdhZVlWdz09
Examination Committee
- Assistant Professor Paraskevi Panagiotopoulou (advisor)
- Professor Ioannis V. Yentekakis
- Assistant Professor Nikolaos Xekoukoulotakis
Abstract
This study deals with the development and operation of an energy efficient and environmentally friendly electricity generation system with intermediate hydrogen production via steam reforming of commercially available liquefied petroleum gas (LPG). The aim of this study is to synthesize, characterize and evaluate catalytic materials for the production of hydrogen via the reaction of steam reforming of propane. Catalysts must be characterized by high activity and selectivity toward H2, as well as high resistance to carbon deposition in order to avoid catalyst deactivation. Thus, the effect of the nature of the metallic phase (Rh, Ru, Ir,Re), the metal loading and the mean particle size of Rh and Ru (0.5-5.0 wt.%) on catalytic activity and selectivity was examined. The effect of the nature of the support (Al2O3, CeO2, ZrO2, SiO2, YSZ, TiO2) and the use of composite metal oxides as supports (CeO2-Al2O3, ZrO2-Al2O3, 50% ZrO2-CeO2) on catalytic performance was also investigated. In addition, the reaction was studied in the absence of a catalyst in order to determine the degree of contribution of homogeneous reactions. Among the various metals examined under conditions of propane steam reforming, optimal catalytic behavior was observed for Rh catalyst supported on γ-Al2O3, which leads to high propane conversions even at temperatures below 600 0C and high selectivity toward H2 production. Increasing metal loading of Rh or Ru from 0.5 to 5 wt.%, results in an improvement of both propane conversion and selectivity to H2. The average size of metal crystallites does not affect the TOF for Rh/Al2O3 catalysts. In contrast, the specific reaction rate increases significantly with increasing the size of Ru particles. Results obtained from the investigation of the effect of the support nature indicated greater activity when Rh is dispersed to YSZ or TiO2 than on CeO2. It was also found that the use of composite metal oxides as supports (10 wt.% CeO2-Al2O3,10%ZrO2-Al2O3 και 50 wt.% CeO2-ZrO2) leads to a significant improvement of catalytic performance of Rh, with the propane conversion curve being shifted towards lower temperatures.
