Small HC's

Small Hydrocarbons

The combustion and pyrolysis of small hydrocarbons such as methane and ethane play an important role in industries ranging from power generation to the production of valuable chemical feedstocks. Many scientists have studied the pyrolysis and oxidation of these species at pressures below 10 bar and a number of models for these systems have been published. Quite frequently the models may have been optimised for particular conditions e.g. lean fuel blends, moderate reaction pressures etc. Some of the reaction mechanisms that are commonly used to simulate small hydrocarbon combustion are shown in the side bar. While all of these mechanisms perform well within the limits that they have been optimised for they may not perform so well at elevated pressures or for rich fuel mixtures outside of the optimisation range.

We have recently generated a large amount of experimental data with the high-pressure shock tube that should allow a more comprehensive mechanism for small hydrocarbon oxidation to be developed than is currently available. The experimental data spans the range

Reaction pressures of 5 bar, 15 bar, 40 bar, 340 bar, 613 bar and 1000 bar

Reaction temperatures 1050 K to 1400 K

Reaction times 1.3 ms to 1.8 ms

Soichiometries 1, 5 and pyrolysis

and an example of the data are shown to left. Currently we are using a mechanism developed by Pope and Miller (see above) as the basis for our model. For more details please consult:

a) “High pressure, high temperature shock tube studies of ethane pyrolysis and oxidation”

Robert S. Tranter , Raghu Sivaramakrishnan , Kenneth Brezinsky and Mark D. Allendorf

Phys. Chem. Chem. Phys., 2002, 4 (11), 2001 - 2010

b)”High-pressure single-pulse shock tube investigation of rich and stoichiometric ethane oxidation”

R.S. Tranter, H. Ramamoorthy, A. Raman,K. Brezinsky and M. D. Allendorf

29th Intermational Symposium on Combustion

phi=1

613bar

Species profiles from 613 bar ethane oxidation experiments. Black points [C2H6], Green points [CO], Red points [C2H4}, Blue points [C2H2].

A few examples of mechanisms used to simulate small hydrocarbon combustion.

^{Gri-Mech 3.0}

^{http://www.me.berkeley.edu/gri_mech/version30/text30.html}

^{Pope and Miller M1A}

^{C. J. Pope and J. A Miller; Proc. Combust. Inst. 2000,28, 1519}

^{Konnov 0.5}

^{http://homepages.vub.ac.be/~akonnov/}

^{Leeds Methane Mechanism}

^{http://www.chem.leeds.ac.uk/Combustion/methane.htm}