High temperature gas-phase reactions are of significant academic and practical importance in many fields including combustion, pyrolysis and process engineering. The activity of this group will include (i) evaluation of the rate parameters of the elementary reactions related to basic fuels and also new fuel species like oxygenates (ii) assessment of the uncertainty limits of the rate parameters (iii) dissemination of the results using Web techniques.
Detailed kinetic reaction mechanisms are widely used in astrochemical, atmospheric, and combustion modelling. Currently there are task groups that deal with the collection and evaluation of elementary reactions data in astrochemistry (see KInetic Database for Astrochemistry, https://kida.obs.u-bordeaux1.fr). There are several groups dealing with the collection of reaction rate data in atmospheric chemistry, like the IUPAC Subcommittee for Gas Kinetic Data Evaluation (https://iupac.pole-ether.fr) and the US evaluation group lead by the Jet Propulsion Laboratory (JPL): see “Chemical Kinetics and Photochemical Data for Use in Atmospheric Studies” https://jpldataeval.jpl.nasa.gov/. Also, there is an evaluation panel for the study of chemical kinetics database on oxygenated volatile organic compounds (VOCs) gas phase reactions (https://www.eraorleans. org/eradb/).
In contrast to the significant activity in atmospheric chemistry, the situation is much worse for the reactions at combustion temperatures. The temperature range to be investigated is between 500 K and 2500 K. The lower limit approximately corresponds to the limiting temperature of low-temperature hydrocarbon combustion, while the upper limit corresponds to the top temperature of most flames. While this would be the focus range, the intent is to maintain consistency with data pertaining to lower temperatures, as well, in cases where such data are available. Note, that several members of the proposed group have a background also in atmospheric chemistry and they may ensure the consistency between the overlapping kinetic data related to both high and atmospheric temperature reactions.
The most comprehensive depository of high temperature gas kinetics data is run by the NIST (Chemical Kinetics Database: https://kinetics.nist.gov/kinetics). However, NIST only collects data and do not evaluate them. Considering the evaluation of the elementary reactions at high temperature, there was significant early work by Kondratev, Warnatz and Tsang et al. till the early 1990s. Later, the main activity was within the group lead by Prof. Baulch. This group published their results in three publications (J. Phys. Chem. Ref. Data, 21 (1992) 411-734; Combust. Flame, 98 (1994) 59-79; and J. Phys. Chem. Ref. Data, 34 (2005) 757-1397). Since the Baulch group stopped their activity, no similar work was carried out in the field of high temperature gas kinetics.
The scope of the selection of the elementary reactions to be evaluated will be different from those of the Baulch group. In the 1990’s, the main aim of combustion chemistry was the quantitative understanding of the combustion of basic fuels, like natural gas. The new emphasis in combustion chemistry is serving the needs of environmental protection, which includes the description of the combustion of renewable fuels and fuel additives, promoting the development of more efficient engines, and helping to lower pollutant emission (“clean combustion”). The proposed activity will follow the good practice of the Baulch group to produce a single set of critically evaluated rate parameters for each selected elementary reaction but with significant improvements: (i) the selection of the rate parameters will follow the recent progress of combustion chemistry, like the increased importance of oxygenates; (ii) the evaluation will be based not only on experimental data, but also on theoretical (like transition state theory/master equation) calculations; (iii) the uncertainty information will refer to not only the rate coefficient, but also all evaluated rate parameters; (iv) the results will be published not only in archived publication, but also in a searchable Web database.
An important feature of the planned project is that both experimental and theoretical determinations of the rate coefficients will be considered. These two types of information together will provide a more realistic assessment. Several members of the group are leading experts of the theoretical calculation of rate coefficients.
July 2019 – interim report PDF 2014-028-2-100_report20190701
Dec 2020 update – An interactive web site at address https://k-evaluation.elte.hu/ was set up. This database currently contains rate parameters for 114 high-temperature gas-phase elementary reactions. The “users” may use the database that contains Arrhenius parameters of gas phase elementary reactions determined in direct measurements, theoretical calculations or have been used in modelling studies. Also, the “users” may recalculate the estimated temperature dependent uncertainty limits of the rate coefficients. Anyone may become an “editor” of this data base upon request. The “editors” have the right to upload data sheets for new reactions and to add, delete or modify existing data sheets. The “editor” status may be granted to any registered user upon request to the administrator <email@example.com>
Page least updated 4 Jan 2021