Development Of A Global Mechanism For Oxy-Methane Combustion In A Co2 Environment

Abstract

There has been some recent work on the global kineticmodeling of flames in oxy-fuel combustion for methane. Themain challenge is that none of the mechanisms were developedto understand the time-scales of ignition. Here, a 3-stepmechanism was developed for methane combustion in oxy-fuelenvironment. The mechanisms were simulated using a closedbatch homogeneous batch reactor with constant pressure andcompared to baseline simulations performed using a detailedmechanism. All simulations were performed for methane used amixture of XCH4 = 0.05, XO2 = 0.10 and XCO2 = 0.85.Mechanisms were altered using the global mechanismequilibrium approach to ensure that the steady-state valuesmatched the reference values and were further altered using anoptimization scheme to match experimental data that was takenin a shock tube. Simulation results of methane, CO timehistories, and temperature profiles from the global mechanismwere compared to those from the detailed mechanism. Ignitiondelay times were used to represent the time-scales ofcombustion. This was defined for current simulations as thetime required for methane concentration to reach 5% of itsinitial value during combustion. Using this approach, the 3-stepmethane combustion mechanism showed excellentimprovement in the ignition timing over a range of pressures (1to 10 bar) and initial temperatures (1500 to 2000 K) for bothlean and stoichiometric mixtures but fails to predict ignitiondelay times at 30 bar or the ignition delay times of fuel richmixtures. Ongoing effort focuses on extending this new globalmechanism to higher pressures and to syngas mixtures.

Publication Date

1-1-2018

Publication Title

Proceedings of the ASME Turbo Expo

Volume

9

Document Type

Article; Proceedings Paper

Personal Identifier

scopus

DOI Link

https://doi.org/10.1115/GT2018-75169

Socpus ID

85053874167 (Scopus)

Source API URL

https://api.elsevier.com/content/abstract/scopus_id/85053874167

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