TY - JOUR
T1 - Burner development and operability issues associated with steady flowing syngas fired combustors
AU - Lieuwen, Tim
AU - McDonell, Vince
AU - Santavicca, Domenic
AU - Sattelmayer, Thomas
N1 - Funding Information:
The first three authors of this article are participants in the University Turbine Systems Research (UTSR) program, a DOE-sponsored program that is investigating fundamental problems that are of interest to the gas turbine community, with particular focus upon coal-derived fuels. This publication was prepared with the support of the US Department of Energy, Office of Fossil Energy, National Energy Technology Laboratory, under contracts 03-01-SR95, 03-01-SR109, 03-01-SR111, 04-01-SR114 (Dr. Richard Wenglarz, contract monitor). Any opinions, findings, conclusions, or recommendations included herein are those of the authors and do not necessarily reflect the views of the DOE. In addition, the assistance of Mr. Q. Zhang in performing chemical kinetic calculations and of Dr. J.G. Lee and Mr. E. Gonzalez in performing the flame structure and instability measurements is gratefully acknowledged. The effort of David Beerer on the ignition delay measurements and calculations is also acknowledged.
PY - 2008/6
Y1 - 2008/6
N2 - This article addresses the impact of syngas fuel composition on combustor blowout, flashback, dynamic stability, and autoignition in premixed, steady flowing combustion systems. These are critical issues to be considered and balanced against emissions considerations in the development and operation of premixed combustors. Starting with blowout, the percentage of hydrogen in the fuel is suggested to be the most significant fuel parameter, which is more fundamentally related to the hydrogen flame's resistance to stretch induced extinction. Turning to flashback next, it is shown that multiple flashback mechanisms are present in swirling flows, and the key thermophysical properties of a syngas mixture that influence its flashback proclivity depend upon which flashback mechanism is considered. Flashback due to turbulent flame propagation in the core flow and the interaction of heat release with pulsations are less critical, whereas flame propagation in boundary layers and flashback due to the interaction of the heat release with vortex breakdown dynamics are most significant. Then, combustion instability is considered. The key flame parameter impacting the conditions under which instabilities occur is the spatial distribution of the flame. As such, fuel composition influences dynamics through impacts upon flame speed and the flame stabilization point. Furthermore, certain syngas fuel compositions are not more inherently stable than others - rather, each mixture has particular islands in the parameter space of, e.g., velocity and fuel/air ratio, at which instabilities occur. Changes in fuel composition move these islands around but do not necessarily eliminate or introduce instabilities. Relative to autoignition, measurements indicate that the ignition delay time exceeds typical premixer residence times, though by a substantially less margin than suggested by the calculations. Recent experiment work suggest that current detailed kinetic mechanisms developed for hydrogen/carbon monoxide ignition overestimate the ignition delay time, indicating the need for additional kinetic work in the low temperature, high pressure regime.
AB - This article addresses the impact of syngas fuel composition on combustor blowout, flashback, dynamic stability, and autoignition in premixed, steady flowing combustion systems. These are critical issues to be considered and balanced against emissions considerations in the development and operation of premixed combustors. Starting with blowout, the percentage of hydrogen in the fuel is suggested to be the most significant fuel parameter, which is more fundamentally related to the hydrogen flame's resistance to stretch induced extinction. Turning to flashback next, it is shown that multiple flashback mechanisms are present in swirling flows, and the key thermophysical properties of a syngas mixture that influence its flashback proclivity depend upon which flashback mechanism is considered. Flashback due to turbulent flame propagation in the core flow and the interaction of heat release with pulsations are less critical, whereas flame propagation in boundary layers and flashback due to the interaction of the heat release with vortex breakdown dynamics are most significant. Then, combustion instability is considered. The key flame parameter impacting the conditions under which instabilities occur is the spatial distribution of the flame. As such, fuel composition influences dynamics through impacts upon flame speed and the flame stabilization point. Furthermore, certain syngas fuel compositions are not more inherently stable than others - rather, each mixture has particular islands in the parameter space of, e.g., velocity and fuel/air ratio, at which instabilities occur. Changes in fuel composition move these islands around but do not necessarily eliminate or introduce instabilities. Relative to autoignition, measurements indicate that the ignition delay time exceeds typical premixer residence times, though by a substantially less margin than suggested by the calculations. Recent experiment work suggest that current detailed kinetic mechanisms developed for hydrogen/carbon monoxide ignition overestimate the ignition delay time, indicating the need for additional kinetic work in the low temperature, high pressure regime.
KW - Autoignition
KW - Blowoff
KW - Combustion
KW - Flashback
KW - Instability
UR - http://www.scopus.com/inward/record.url?scp=46249097928&partnerID=8YFLogxK
U2 - 10.1080/00102200801963375
DO - 10.1080/00102200801963375
M3 - Article
AN - SCOPUS:46249097928
SN - 0010-2202
VL - 180
SP - 1169
EP - 1192
JO - Combustion Science and Technology
JF - Combustion Science and Technology
IS - 6
ER -