Impact of HAN Ternary Propellant System Decomposition on Catalytic Sustainability

• Published in: Propellants, explosives, pyrotechnics explosives, pyrotechnics, 2021-03, Vol.46 (3), p.440-449
• Main Authors: Agnihotri, Ruchika, Oommen, Charlie
• Format: Article
• Language: English
• Subjects: Aluminum oxide; Aqueous solutions; Catalysts; Cerium oxides; Cobalt doped cerium oxide; Decomposition reactions; Fuels; HAN-based propellants; Hydroxylammonium nitrate; Hydroxylammonium nitrate (HAN); Iridium; Iridium catalyst; Nuclear fuels; Propellant decomposition; Propellant injection; Sustainability; Ternary propellant system; Ternary systems; Thrusters; X ray photoelectron spectroscopy
• ISSN: 0721-3115; 1521-4087
• DOI: 10.1002/prep.202000110

Aqueous solution of Hydroxylammonium nitrate (HAN) in combination with a suitable fuel has been explored as a promising high performing green monopropellant in recent times. The current study primarily explores the effect of the addition of a fuel component into HAN solution on the sustainability of a recently developed catalyst which was examined for the only binary system consisting of HAN and water. The HAN ternary system examined was HAN: methanol: water in 70 : 15 : 15 (w/w) composition. The endurance of an ‘iridium over alumina’ catalyst and an indigenously developed cobalt doped ceria‐based catalyst was analysed using a batch reactor wherein a pressure rise during decomposition of propellant whilst a pulse mode operation was monitored. Catalysts were also characterized via SEM/EDS, XRD, and XPS to identify changes over the period of sequential injection in the batch reactor. Doped ceria catalyst was found to be far robust and resistant to any poisoning when compared to iridium catalyst at run time of the operation involving nearly 45 sequential injections of propellant over the catalyst.