Experimental evaluation of catalysts for monopropellant hydrazine propulsion

Abstract

Many monopropellant propulsion systems use a catalyst to decompose hydrazine. Problems of catalyst attrition have given rise to various special processes intended to improve catalyst durability. Precalcined and rounded catalysts were evaluated by measurements of mechanical properties and motor firing characteristics. The results were compared to those obtained with the original catalyst. For the conditions tested, no significant differences in performance or in catalyst activity were observed, and only the precalcining process resulted in a reduction in catalyst loss and breakup. Laboratory measurements of porosity and of thermal expansion coefficient indicate that this improvement is probably due to less catalyst shrinkage and to a more open pore structure.

Cluster size effects on sintering, CO adsorption, and implantation in Ir/SiO2

“…Effects such as particle sintering and support degradation at elevated temperatures tend to reduce the activity of such catalysts. 21,22 While the catalysts usually operate at high temperatures, low temperature activity is also necessary to provide efficient cold starts in intermittent operation.…”

Catalytic Decomposition of Energetic Compounds: Gas Generators and Propulsion1A list of abbreviations/acronyms used in the text is provided at the end of the chpater

“…A description of the Shell catalyst, its preparation and its application, are provided by the inventor Voge et al [83,84]. The outstanding properties of Shell 405 catalysts are presumably due to a more open structure [85] or to the presence of a high fraction of η-alumina crystals (size ca. The outstanding properties of Shell 405 catalysts are presumably due to a more open structure [85] or to the presence of a high fraction of η-alumina crystals (size ca.…”