Etude de la combustion de gaz de synthèse issus d'un processus de ...

Chapter 3
These results show that the pressure has a definite effect on flammability limits of the
syngas-air mixtures reducing the flammable region in the lean side.
For hydrocarbon-air mixtures the rich limit become much wider with increasing
pressure and the lean limit is not appreciably affected (Kuo, 2005). There is a
dependence of the width of flammable region on the order of chemical reactions. The
second order reactions that occur at low pressures give room to first order reactions at
high pressures. To compare hydrocarbons flammability limits behavior with syngas
higher pressure experiments are needed.
3.2.3 Pressure measurement on static chambers
tel-00623090, version 1 - 13 Sep 2011
A set of experiments were made in order to determine the repetition of the measured
pressure versus time during the combustion of syngas-air mixtures. Figure 3.7 shows a
set of three experiments with updraft syngas-air mixture in spherical chamber. Figure
3.8 shows a set of three experiments with updraft syngas-air mixture in rectangular
chamber. In both cases the following initial conditions, P i = 1.0 bar, T i = 293 K and
stoichiometric equivalence ratio where used. A very good repetition of the pressure
signal was obtained in both cases. This behavior was verified for every syngas
composition except for very lean mixtures. In those cases the number of experiments
was increased to five, especially in the rectangular chamber due to higher leakages.
7
6
5
(1) (2)
(3)
Pressure (bar)
4
3
2
1
0
Shot 1
Shot 2
Shot 3
0 10 20 30 40 50 60 70 80 90 100
Time (ms)
Figure 3.7 - Pressure versus time in spherical chamber
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