Dual Firing of Hydrogen and JP-8 for External Combustion Based Power Sources

摘要

Flame control, particularly at lean conditions, is a critical requirement for external combustion based power sources such as thermoelectric and thermophotovoltaic generators. This research investigates the use of hydrogen co-fired with heavy hydrocarbons for improved fuel efficiency, operational characteristics, and environmental protection. The availability of in-situ produced hydrogen from JP-8 fuel reforming allows dual firing of hydrogen and JP-8 to be a feasible approach for small power applications, such as the battlefield. Previous numerical simulations indicate that hydrogen reformate can provide improved fuel conversion, better flame stability and higher fuel burnout. In the present research, experiments are conducted on the impact of hydrogen on a 9 kW_(th) JP-8 combustion test stand. Temperature profiles and emissions are studied. In the open diffusion flame, hydrogen addition increases flame temperature and reduces hydrocarbon and carbon monoxide emissions. NO_x emissions are generally increased due to the increased temperatures. The reduction in hydrocarbon emissions is especially evident with coaxially introduced secondary air. Hydrogen provides higher temperatures throughout the flame, which contribute to complete combustion. Complete combustion is important for fuel efficiency, operational reliability and emissions control. The benefits of hydrogen addition are observed with hydrogen providing only 5-10% of the energy content which is important for implementing this technique in practical power sources.