Hydrogen production from burning and reforming of ammonia in a microreforming system

• Published in: Energy conversion and management 2012-04, Vol.56, p.184-191
• Main Authors: Kim, J.H., Um, D.H., Kwon, O.C.
• Format: Article
• Language: English
• Subjects: Ammonia (NH 3) burning; Ammonia reforming; Applied sciences; Energy; Exact sciences and technology; Hydrogen (H 2); Micro-combustor; Microreforming system
• ISSN: 0196-8904; 1879-2227
• DOI: 10.1016/j.enconman.2011.12.005

► We conduct experiments for reforming and burning NH 3 in a microreforming system. ► The microreforming system produces 5.4 W of H 2 with a conversion rate of 97.0%. ► The best performance is observed for stoichiometric NH 3–H 2–air mixtures. ► The system performance improves with enhanced H 2 substitution. ► Potential of using NH 3 as a carbon-free fuel in production of H 2 is found. Hydrogen (H 2) is produced by burning and reforming ammonia (NH 3) in a microreforming system. A micro-combustor that burns H 2-added NH 3–air mixtures as a heat source is a cylinder with an expanded exhaust outlet that facilitates ignition and an annular-type shield that adopts a heat-recirculation concept. A micro-reformer that converts NH 3 to H 2 using ruthenium as a catalyst surrounds the micro-combustor, which facilitates heat transfer between the micro-combustor and micro-reformer. Performance of the microreforming system is affected by the fuel-equivalence ratio and micro-combustor inlet velocity of NH 3–H 2–air mixtures and the concentration of the substituted H 2 in the fuel gas. The production rate of H 2, the conversion rate of NH 3, the overall efficiency of the microreforming system and the NO x concentration in the exhaust gas from the micro-combustor for optimized operating conditions are 5.4 W (based on lower heating value), 97.0%, 10.4% and 158 ppm, respectively. This supports the potential of using NH 3 as a clean, carbon-free fuel for both burning and reforming in microreforming systems.