Investigation of autothermal reforming catalysts for portable auxiliary low-power units

摘要

Today, Fuel Cell (FC) technologies give the opportunity for electric power generation in diverse applications such as recreational yachts, vehicles, etc where portable, low-cost/volume/weight power sources are required. Propane/LPG is a fuel that is readily available in such cases and therefore the combination of an LPG Auto Thermal Reformer (ATR) with a High-Temperature Polymer Electrolyte Membrane (HT-PEM) FC looks very attractive to be used as an auxiliary power unit because of simple thermal integration efforts and less requirements concerning the choice of the materials for the key components of the system. For safety reasons, LPG contains sulfur compounds such as mercaptans, triophen and sulfides, that are used as odorants. However, during reforming even small amounts of sulfur (higher than 1 ppm) can have detrimental effects in the fuel cell catalysts, the Water Gas Shift (WGS) catalyst and possibly to the reforming catalyst. A common practice is to remove the sulfur compounds immediately after the introduction of the fuel into the system. For LPG this is quite difficult since higher hydrocarbons may adsorb competitively to the sulfur compounds. In addition, sulfur removal upstream of the reformer requires bulky sulfur traps which are not suitable for portable and transport related applications. Reformate desulfurization downstream of the reformer provides certain advantages being quite straightforward with less system energy and hardware requirements; however, a sulfur tolerant reforming catalyst is required.