International Journal of Hydrogen Energy, Vol.39, No.12, 6764-6773, 2014
The features of ignition and combustion of composite propane-hydrogen fuel: Modeling study
The extensive numerical analysis of the features of self ignition and formation of NO and CO during combustion of blended fuel, consisting of propane and hydrogen, with air is considered on the basis of extended detailed kinetic model involving both high and low temperature submechanisms of propane oxidation. It has been shown that for the blended C3H8-H-2 fuel there exists the temperature region, where the ignition of the C3H8-H-2 air mixture occurs faster compared to pure propane. However, this region is not broad enough and has low and high temperature boundaries (T-b and T-h, respectively). At the initial temperature of fuel-air mixture T-o < T-b, the induction time of blended C3H8-H-2 fuel is greater than that of pure propane and, at T-o > T-b, the admixture of a small amount of propane (1 similar to 5% per volume) to hydrogen accelerates the ignition. The values of T-b and T-h depend on the composition of blended fuel and initial pressure. It has been revealed that the addition of hydrogen to propane increases the flame speed and extends the flammability thresholds both in fuel-lean and in fuel-rich regions, but doesn't result in the substantial change of the concentrations of main pollutants NO and CO in the combustion exhaust. However, the addition of hydrogen to fuel-lean propane air mixture allows one to provide the stable combustion of leaner fuel air mixture and, thus, to reduce notably the emission of NO and CO compared to that for the combustion of pure propane air mixture. Copyright (C) 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.
Keywords:Ignition;Flame speed;Detailed kinetic mechanism;Composite propane-hydrogen fuel;NO and CO emission