Interest in rocket grade hydrogen peroxide has been renewed in recent years by the requirement for non-toxic alternatives to rocket propellants currently in use. In mid 1990's, there has been renewed interest on hydrogen peroxide for the reason of low toxicity and enhanced versatility. Recently, silver screen catalyst beds have been widely used for the decomposition process of hydrogen peroxide. However, catalytic silver screen has several shortcomings such as low melting point, non-uniform flow path and large pressure drop. With these as background, this paper reports characteristic of catalytic decomposition of hydrogen peroxide with perovskite material based catalyst.
$La_{0.8}Sr_{0.2}CoO_3(LSC)$ catalyst is chosen as catalyst. LSC has merits of high ionic conductivity and excellent electro-chemical properties in high temperature even around 1000℃. LSC is prepared by sol-gel method. Several type of catalyst supports are compared in view of quality of catalyst coating and reactivity of catalyst coated beds. Cordierite-based monolith are selected as an alternative to the screen-based devices
Hydrogen peroxide decomposes into mixture of superheated steam and oxygen only when the concentration of hydrogen peroxide is above 67% by weight. Low grade commercial hydrogen peroxide was distilled into higher concentration of up to 92% by weight using in house distillation plant. Apparent activation energy of LSC catalyst on hydrogen peroxide was measured to estimated the reactivity. The apparent activation energy was measured at fixed flow rate reactor in the temperature range of 200~1000℃. Two apparent activation energies were obtained. A reactor with a diameter 20mm and length of 60mm was used for reaction experiment. From the reaction of hydrogen peroxide of 80% by weight, temperatures at several locations along the reactor axis were measured. Except low temperature in inlet region by phase change, temperature distribution within reactor shows proper decomposition temperatures.
With the preliminary results on reactivity and operating parameters, the sizing of a gas generator was carried out to process 5g/s of mass flow at 17atm of chamber pressure using hydrogen peroxide of 80% by weight. This reactor chamber can generate characteristic velocity up to 857.7m/s given theoretical expansion. However, in an actual reactor, chamber pressure was lower than the design pressure resulting in lower characteristic velocity.
