A numerical study on the effect of hydrogen/reformate gas addition on flame temperature and NO formation in strained methane/air diffusion flames

Abstract

A numerical study on the effect of hydrogen/reformate gas addition on flame temperature and NO formation in strained methane/air diffusion flames Guo, Hongsheng; Neill, W. Stuart This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues.Other uses, including reproduction and distribution, or selling or licensing copies, or posting to personal, institutional or third party websites are prohibited. This paper investigates the effects of hydrogen/reformate gas addition on flame temperature and NO formation in strained methane/air diffusion flames by numerical simulation. The results reveal that flame temperature changes due to the combined effects of adiabatic temperature, fuel Lewis number and radiation heat loss, when hydrogen/reformate gas is added to the fuel of a methane/air diffusion flame. The effect of Lewis number causes the flame temperature to increase much faster than the corresponding adiabatic equilibrium temperature when hydrogen is added, and results in a qualitatively different variation from the adiabatic equilibrium temperature as reformate gas is added. At some conditions, the addition of hydrogen results in a super-adiabatic flame temperature. The addition of hydrogen/reformate gas causes NO formation to change because of the variations in flame temperature, structure and NO formation mechanism, and the effect becomes more significant with increasing strain rate. The addition of a small amount of hydrogen or reformate gas has little effect on NO formation at low strain rates, and results in an increase in NO formation at moderate or high strain rates. However, the addition of a large amount of hydrogen increases NO formation at all strain rates, except near pure hydrogen condition. Conversely, the addition of a large amount of reformate gas results in a reduction in NO formation.Crown

Kinetic and dynamic analysis of hydrogen-enrichment mixtures in combustor systems – A review paper

“…In the literature, numerous reports show that NOx formation would be almost double if hydrogen was added to the hydrocarbon mixtures [2,16,18,28,29,36,38,49,57,58,65,[68][69][70][71][72][73][74]. Tuncer et al [49] in their work have described on how hydrogenenrichment would allow the combustion to become more sustainable at the linear equivalence ratios than those with methane [49].…”

“…Studies on important parameters (including auto-ignition regimes [26], ignition delay [26], burning velocity [25,30,34], flame temperature [25,28,29,32,33,57], flame length [26][27][28][29] and gas emissions [27,29,[31][32][33][34][92][93][94] of hydrogen-enrichment have been done on different operating conditions i.e. plate [34], co-flow [26,33], sinter [32], flame flat [30,31], Bunsen [28,29], single-port atmospheric [27], drilled-port atmospheric [27], combustor shell [49], PSI (Paul-Scherrer-Institute) [48], ultra-lean counter-flow [92], swirl-stabilized [94], Lamborghini Calor Eco 8/00870012 liquid fuel [93] and slot [25] burners and the discussions are highlighted below.…”

“…As far as authors' concern, literature studies have focused on the effect of the addition of hydrogen to: (a) dynamics and chemical characteristics (kinetics [50,63,64], flame stability [37,39,49,51,[65][66][67], NOx [2,16,18,36,38,49,57,58,65,[68][69][70][71][72][73][74], CO [16,27,28,31,38,65,73] and CO 2 emissions [16,18,31,33,36,75], Markstein length [5,7,10,36,37,39,43,50,54,56,67,[76]…”

“…The parameters affecting hydrogen-hydrocarbon mixtures have been studied, including flame configurations, e.g., laminar premixed [55,56], non-premixed [57] and partially premixed flames [7,58], as well as burner-stabilized [59,60] and swirl-stabilized turbulent flames [47,61,62].…”

Structure and reaction zones of hydrogen – Carbon-monoxide laminar jet diffusion flames

“…They had established stable non-premixed and partially premixed counter-flow flames and studied them both experimentally and numerically. Further, the effect of syngas addition on NO formation in strained methane/air diffusion flames was investigated by Guo and Neil [9]. Ding et al [10] numerically investigated the extinction limits and emission characteristics of dry syngas with equimolar CO/H 2 , moist syngas (with 20% H 2 O) and impure syngas (with 5% CH 4 ) at lean premixed combustion conditions.…”