Combustion Characteristics of HAN-based Green Propellant Assisted with Nanoporous Active Carbons

Combustion of hydroxylammonium nitrate (95 wt.% HAN) ‒ water solution in presence of high specific surface area activated carbons is investigated in a constant-pressure bomb within the pressure range of 1‒6 MPa. The linear burning rate increased for the system of HAN admixed with activated carbons compared to those of the HAN alone. Moreover, the thermal decomposition of HAN (95 wt.%) ‒ water solution spiked with activated carbons was assessed by DTA – TG method. In the presence of activated carbons, the ability to trigger the decomposition at a lower temperature (86 °C vs 185 °C) was observed. The volatile products formed in the course of thermal decomposition of HAN, spiked with activated carbons were characterized by electron ionization mass spectrometry analysis. Primary products of HAN decomposition: m/z = 33 (NH2OH) and m/z = 63 (HNO3), which are further responsible for the formation of secondary products such as N2O, NO, HNO2, NO2, O2 etc. Significant reduction of NOx emissions during thermal decomposition of HAN (95 wt.%) ‒ water solution was observed (ca. 30%) in presence of activated carbons

HAN and ADN as liquid ionic monopropellants: thermal and catalytic decomposition processes

International audienceBinary HAN and ADN aqueous solutions have been synthesized, then thermally and catalytically decomposed. Binary HAN mixtures were prepared with different concentrations: 95,80 and 60 wt.%. Whereas ADN solution contains are: 75, 60 and 50 wt.%. The candidate catalysts were prepared by impregnation of alumina doped by lanthanum oxide with active phase precursors: iridium for HAN and copper oxide for ADN and characterized by transmission electron microscopy. X-ray diffraction and chemisorption. The decomposition processes were followed by thermal analysis and a constant batch reactor. This work shows the essential effect of monopropellant concentrations to determine the best green propellants for industrial applications as reaction control systems. Moreover, HAN and ADN solutions are more efficient for catalytic decomposition due to the absence of stabilizer to inhibit catalysts. The (10%)Ir/Al2O3-La2O3 + HAN(95%) and the (10%)CuO/Al2O3-La2O3 + ADN(75%) associations show lower decomposition temperatures, larger reaction rates and leads to higher amount of gas phase products, giving the most efficient systems