Elementary Reactions in the Methanol Oxidation System. Part I: Establishment of the Mechanism and Modelling of Laminar Burning Velocities

Abstract

A set of combustion relcvant rate coefficients recommended by a group of European kincticists has been tested by calculating laminar burning velocities. Virtually without any adjustments, a good match with cxperirnental data has been achieved for H2/air flames, H2/CO/air flames, and CHJair flamcs. In ordcr to extend this set by inclusion of the reactions forming the CH,OH oxidation subsystem, the current knowledge of these reactions if first reviewed. The extended set yields calculated burning velocities for CH?OH/air flames in good agreement with measurements recently obtained under stretch free conditions. By using a sensitivity analysis, the remaining deficiencies of the model are highlighted and it is made clear where further experimental work is particularly needed.

A Comprehensive Study of Methanol Kinetics in Freely-Propagating and Burner-Stabilized Flames, Flow and Static Reactors, and Shock Tubes

“…C) chemistry has been shown (Egolfopoulos et al, 1990 to decrease the laminar flame speed of atmospheric, stoichiometric Cj-hydrocarbon/air mixtures by 1.5 to 2.5 cm/s. Grotheer and Keirn (1989) have recently conducted a detailed numerical study of methanol flames with the latest information of Norton andDryer (1989) andTsang (1987), predicting laminar flame speeds of methanol/air mixtures at p = I atm and T" = 298 K conditions. In this study, the one-dimensional, time-dependent flame code of Warnatz (1978) was used and a number of revisions was adopted due to significant overprediction of the flame speeds of rich mixtures.…”

“…There are various advantages and disadvantages in the use of methanol as a practical fuel (Bowman, 1975;Aronowitz et al, 1979;Westbrook and Dryer, 1979;Guider, 1982;Dove and Warnatz, 1983;Cribb et al, 1984;Grotheer and Keirn, 1989;Norton andDryer, 1989, 1990;Norton, 1990). Specifically, the major advantages are: (a) convenienl slorage in vehicles as a liquid fuel under normal temperature and pressure, (b) diversified, petroleum-independent sources of production, such as natural gas, wood, coal, and renewable biomass feedstock, (c) reduced propensity for the formation of pollutants such as soot, CO, NO,., and unburned hydrocarbons, and (d) high octane number rating.…”

Theoretical determination of the heat of formation of methylene

“…The latter in turn implies a predicted enthalpy change for reaction (1) of ∆H¨0© 0 1© 6 kJ mol 1 , i.e., the reaction is essentially thermoneutral, in contradiction to the findings of Ref. [10]. The relatively large uncertainty arises from quoted errors in the heats of formation of C, CH 3 , and OH [2].…”

“…The value of Dibeler et al [9] has to be corrected for rotational energy effects at threshold [8]. Grotheer et al [10] have derived the enthalpy change at 300K for reaction (1) from rate constants and branching ratios to be ∆H¨8 2 kJmol 1 . This cannot be reconciled with the literature data [2], and therefore a methylene heat of forma-…”

A reduced combustion kinetic model for the methanol-gasoline blended fuels on SI engines

“…However, the ignition delay time for Egolfopoulo's mechanism [11] did not agree well with the Bowman's results [6]. Subsequently, Grotheer et al [12] developed another comprehensive mechanism for the prediction of laminar flame speed and auto-ignition in SI engines. Mechanism proposed by Held and Dryer [13] was a relatively complete detailed mechanism, which showed good agreement with the results of shock-tube, flow-reactor, static-reactor and premixed laminar flame speed experiments over a wide range of conditions.…”