The development and characterization of aluminum fueled power systems and a liquid aluminum fuel

Abstract

Various aluminum-water reactions were thermodynamically analyzed across a wide range of temperatures and pressures to determine the most favorable reaction under each condition. Results show that under most achievable temperatures and pressures the reaction will produce AlOOH, however at low temperatures and high pressures, this will transition to a reaction producing Al(OH)₃. This model was then corroborated experimentally using XRD and FTIR to identify the aluminum-water reaction products created at varying temperatures and pressures. A new Ga In eutectic-limited surface coating method was developed to produce effective, consistent, aluminum fuel. This coating method also allowed for the study of the effects of increased eutectic concentration on aluminum reaction yield. These reaction yield results showed a minimum threshold concentration of 1.9% eutectic was needed to create reactive fuel, and that adding concentrations beyond that would increase the reaction yield with diminishing returns. Using this aluminum technology, the world's first aluminum fueled car was made. A 10 kW power system fueled by an aluminum-water reaction was successfully integrated into a BMW i3 to replace its range extender and to power the vehicle. With a vision towards creating simpler power systems in the future, a liquid aluminum fuel was also developed. This fuel works by suspending 65% aluminum particles by mass into a mixture of mineral oil and fumed silica. This newly developed liquid fuel can be pumped easily, stay in suspension for months, and retains full levels of reaction completion. Finally, a joint hydrogen-steam IC engine concept was presented and analyzed. This engine utilizes both the thermal and hydrogen energy created by an aluminum-water reaction and shows ideal system efficiencies of as high as 33% while still operating at practical system pressures.