Hydrogen generation by means of the combustion of aluminum powder/sodium borohydride in steam

Abstract Hydrogen generation by means of the combustion of aluminum powder with sodium borohydride (NaBH 4 ) addition in steam was studied by a pipe furnace at different temperatures. The ignition temperature and the maximum combustion temperature were obtained by an S-type thermocouple. Ignition delay times and combustion efficiencies were measured. The results show that aluminum powder is not ignited at 450 °C, but aluminum powder with NaBH 4 addition is ignited under the same condition. The addition of NaBH 4 significantly decreases the ignition delay time of aluminum powder. Moreover, the ignition delay times of aluminum powder without or with NaBH 4 addition can decrease with increasing the temperature. Combustion products were analyzed by scanning electron microscopy, X-ray diffraction and a portable hydrogen analyzer. The results indicate that NaBH 4 displays a key influence on hydrogen generation. Especially, for aluminum powder with 7 wt% NaBH 4 addition, the obtained maximum volume concentration of hydrogen is about 21,000 ppm at 650 °C.