A review on hydroxylammonium nitrate (HAN) decomposition techniques for propulsion application

Development of green propellant is of importance for safer handling and higher cost effectiveness than conventional toxic hydrazine propellant. Among all green liquid propellant options, hydroxylammonium nitrate (HAN) offers better performance and exhibits lower toxicity than hydrazine. Extensive studies have been conducted on HAN decomposition using different techniques. Due to its ionic nature, HAN can be electrolyzed compared to hydrazine. Therefore, other than conventional thermal and catalytic decompositions, electrolytic decomposition of HAN is also possible. This review first discusses the decomposition mechanisms and summarizes the mechanisms involved in different decomposition techniques (thermal, catalytic, electrolytic and others). This review compares the relevant effects of various parameters in different decomposition techniques, with an overview on HAN-based propulsions systems developments systematically and comprehensively. Finally, this review concludes with future perspectives and challenges of different decomposition techniques. Herein, this work serves as a reference to understand the effects of various parameters under different HAN decomposition techniques, together with the limitations that hinders the application value of the decomposition techniques.