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

Experimental and numerical laminar syngas combustion
A number of other workers (Huang et al., 2004; Hassan et al., 1997; Prathap et al.,
2008; Natarajan et al., 2007) have published laminar burning velocity data over a range
of equivalence ratios at 1.0 bar and room temperature for various other H 2 /CO fuels
(with and without excess nitrogen or carbon dioxide), which could bring more insightful
understanding of the syngas burning velocity behaviour. The results obtained in these
various studies are compared in Fig.4.24.
2.0
tel-00623090, version 1 - 13 Sep 2011
S 0 u (m/s)
1.8
1.6
1.4
1.2
1.0
0.8
0.6
40H 2 -40CO-20CO 2
28H 2 -25CO-47N 2
50H 2 -50CO
40H 2 -40CO-20N 2
25H 2 -75CO
30H 2 -30CO-40N 2
10H 2 -90CO
5H 2 -95CO
0.4
20H 2 -20CO-60N 2
Downdraft (17H 2 -21CO-13CO 2 -1CH 4 -48N 2 )
0.2
Updraft (11H 2 -24CO-9CO 2 -3CH 4 -53N 2 )
0.0
0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0
Equivalence ratio
Figure 4.24 - Comparison of laminar burning velocity for different fuels: syngas (this work). H 2 -
CO mixtures (Hassan et al., 1997), H 2 -CO-N 2 mixtures (Prathap et al., 2008), 40H 2 -40CO-
20CO 2 (Natarajan et al., 2007) and 28H 2 -25CO-47CO 2 (Huang et al., 2004).
The continuous lines in Fig. 4.24 show the laminar burning velocity values for a range
of H 2 /CO mixtures obtained by Hassan et al., (1997); these data clearly show that
increases proportionally with H 2 /CO ratio at any given equivalence ratio.
0
S
u
The dashed lines in Fig. 4.24 show the laminar burning velocity values for a range of
H 2 /CO/N 2 mixtures obtained by Prathap et al., (2008); these data clearly show that
decreases as dilution by N 2 increases but not proportionally. The reason for this
behaviour is the contribution of nitrogen dilution in reducing the thermal diffusivity and
flame temperature of the mixture. Also a shift to higher equivalence ratios in the
burning velocity peak is observed. By crossing both collections of curves one can say
that the effect of dilution is to reduce the burning velocity and the shift to latter
equivalence ratios of the burning velocity peak is primarily due to the amount of CO in
the mixture.
0
S
u
110