Experimental Study on the Effect of Hydrogen Enrichment of Methane on the Stability and Emission of Nonpremixed Swirl Stabilized Combustor

Abstract

An ultra lean mixture (0< O .5 ) o f methane-hydrogen-air was experimentally investi gated to explore the effect o f fuel flexibility on the flame stability and emission o f a non premixed swirl stabilized combustor. In order to isolate the effect o f hydrogen addition to methane, experiments were carried out at fixed fuel energy input to the combustor while increasing the hydrogen content from 0% up to 50% in the methane-hydrogen mixture on volume basis. The combustor fuel energy was then increased up to the range o f typical gas turbine combustors. Equivalence ratio sweep was carried out to determine the lean stability limit o f the combustor. Results show that the hydrogen c ontent in the fuel mixture and fuel energy input have a coupled effect on the combustor lean blow o ff velocity (LBV), temperature and emissions. The LBV increases by ~103% with the addition o f 30% H2. On the other hand, the LBV increases by ~20% as the fuel energy increases from 1.83MWIm3 to 2.75 MWIni3. Burning under ultra lean condition sen>es two pur poses. (I) The excess air supplied reduces the overall combustor temperature with its ensuing effect on low NOx formation. (2) It increases the overall combustor volume flow rate which reduces the residence time fo r NO, formation. The axial temperature profile presented along with the emission data can serve as basis fo r the validation o f numerical models. This would give more insight onto the effect o f hydrogen on the turbulence level and how it would improve the localized extinction o f methane in a cost-effective way.

Oxy-fuel combustion technology: current status, applications, and trends

“…Mokheimer et al numerically investigated the stability and emission of hydrogen enriched methane under very lean air combustion in a diffusion flam. They developed a combustion mechanism that can closely fit with the experimental results by Sanusi et al From their numerical analysis, Mokheimer et al could determine the optimum equivalence ratio at which the CO emission can be eliminated and NOx emission can be limited below 5 ppm. This optimal equivalence ratio was 0.45 for a hydrogen enriched methane fuel mixture with 30% H 2 .…”

Effect of different syngas compositions on the combustion characteristics and emission of a model combustor

“…Syngas combustion characteristics and emission was studied in a vertically positioned swirl-stabilized combustor. The combustor adopted in this study has been used for various experimental studies [32][33][34]. Air was supplied through an eight-vane swirler with vane angle of 45 degrees and deliver to an orifice of 16mm diameter situated at the combustor dump plane.…”

“…In order to validate the governing equations used in this study, experiments were conducted in a swirl stabilized combustor for methane air combustion. Details of the experimental set can be found in [32]. Experiments were carried out with 100% methane and 3.67 MW/m 3 fuel energy input.…”

Feasibility Study of Biogas Reforming To Improve Energy Efficiency and To Reduce Nitrogen Oxide Emissions

“…Lean, premixed fuel-gas combustion has been receiving increased attention recently because of its ability to reduce emissions of nitrogen oxides (NO X ). The reason for the reduction in emissions is because under lean-burn conditions peak flame temperatures are reduced, and the thermal NO X formation rate decreases because it is strongly temperature dependent − and, also, because for a fixed fuel energy input the overall combustor volume flow rate increases, which reduces the residence time available for NO X formation . Using a mixture that is highly fuel lean, on the other hand, may result, potentially, in incomplete/unstable combustion, which may then increase the concentration of carbon monoxide (CO) and unburned hydrocarbons (UHC) in the exhaust gas.…”