Flammability limits, ignition energy, and flame speeds in H2–CH4–NH3–N2O–O2–N2 mixtures

Abstract

Experiments on flammability limits, ignition energies, and flame speeds were carried out in a 11.25-and a 400-liter combustion vessel at initial pressures and temperatures of 100 kPa and 295 K, respectively. Flammability maps of hydrogen-nitrous oxide-nitrogen, methane-nitrous oxide-nitrogen, ammonia-nitrous oxide-nitrogen, and ammonia-nitrous oxide-air, as well as lean flammability limits of various hydrogenmethane-ammonia-nitrous oxide-oxygen-nitrogen mixtures were determined. Ignition energy bounds of methane-nitrous oxide, ammonia-nitrous oxide, and ammonia-nitrous oxide-nitrogen mixtures have been determined and the influence of small amounts of oxygen on the flammability of methane-nitrous oxide-nitrogen mixtures has been investigated. Flame speeds have been measured and laminar burning velocities have been determined for ammonia-air-nitrous oxide and various hydrogen-methane-ammonianitrous oxide-oxygen-nitrogen mixtures. Lower and upper flammability limits (mixing fan on, turbulent conditions) for ignition energies of 8 J are:Flammability limits of methane-nitrous oxide-nitrogen mixtures show no pronounced dependence on small amounts of oxygen (< 5%). Generally speaking, flammable gases with large initial amounts of nitrous oxide or ammonia show a strong dependence of flammability limits on ignition energy.

Flammable gas tank safety program: Technical basis for gas analysis and monitoring

“…The s i g n i f i c a n t a g i t a t i o n associated Assuming R r P r F (Pfahl and Shepherd 1997) present flammability findings from various researchers f o r hydrogen-nitrogen-nitrous oxide-air mixtures which can be compared t o t h e 1 i s t e d compositions. These tabulated compositions can be s p e c i f i e d as: (R) fuel r i c h and t h u s not flammable; (P) p o t e n t i a l l y flammable w i t h an i g n i t i o n source of s u f f i c i e n t l y high energy (> 20 j o u l e s ) ; o r (F) flammable.…”

“…If present in sufficient concentrations, nitrogen may lower the fuel-oxidizer concentration sufficiently that the otherwise flammable mixture becomes inerted. mixture, this occurs at about 60% to 80% nitrogen (Pfahl & Shepherd, 1997).…”

“…al., 1997). The required fuel concentrations at the LFL of hydrogen-ammonia-nitrous oxide mixtures are reduced with increased physical agitation of the gas mixtures and increased ignition energies (Pfahl & Shepherd, 1997;Cashdollar et. al., 1992).…”

Study on flame stability in oxygen-enriched ammonia/N₂/O₂ laminar diffusion flame

“…近年，欧米をはじめとする諸外国を中心にアンモニアを代替燃料とするための研究が行われている (Zamfirescu and Dincer, 2008, Takizawa et al, 2008, Ronny, 1988, Kumar and Meyer, 2013, Duynslaegher et al, 2009, Duynslaegher et al, 2010, Pfahl et al, 2000, Li et al, 2014, Hayakawa et al, 2015a, Hayakawa et al, 2015b, Ichikawa et al, 2015, 武石他, 2015, 武石他, 2016, 小林, 早川, 2016, 小池他, 2016, 武石他, 2017 (水谷, 矢野, 1978, Chung and Lee, 1991, Takahashi and Schmoll, 1990, 小谷他, 2004, Otakeyama et al, 2009 …”

Flammable Gas Refined Safety Analysis Tool Software Verification and Validation Report for Resolve Version 2.5

“…Part I : Analysis Framework for Single-Shell Tanks (Slezak and Williams 1998). (Pfahl and Shepherd 1997).…”