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

Chapter 7
7.2 Recommendations for future work
Research works are open narratives and hence some recommendations are made for
possible developments.
tel-00623090, version 1 - 13 Sep 2011
In order to make precise studies on the use of syngas will be necessary to consider
that its composition will be rather constant. The development of mathematical models
fully validated experimentally may be a very useful tool to determine the final
composition of syngas by changes in initial conditions without laborious and expensive
experimental tests. Besides the best performance of the downdraft syngas
composition, fluidized bed gasification is the technology that has been topic of the most
recent developments. This is due to the fact that downdraft gasification is the ultimate
technology and is limited to low scale systems. In opposite, fluidized bed gasification
can be significant improved by optimizing all the variables evolved to a determined
biomass kind or multi-biomass systems.
Various methods for burning velocity determination are available in the literature, and
thus, some comparison between them could be done in order to determine the error.
The linear methodology adopted in the constant pressure method is currently the most
used, however a novel linear methodology of Tahtouh, (2009) as well as the non-linear
theory of Buckmaster, (1977) could be follow. Thus a research line is open in this case
in terms of comparison between linear and non-linear theories.
In the constant volume method there are also various approaches to the mass burning
rate that could be compared. The linear approximation, introduced by Lewis and Von
Elbe (1961), is still the most widespread analytical relation to interpret burning velocity
data. Differences in laminar burning velocities between the varieties of fractional
pressure rise were quantified by Luijten et al., (2009) for the example case of
stoichiometric methane–air combustion, demonstrating that deviations between burning
velocities from bomb data and other methods can at least partly be ascribed to the
limited accuracy of the linear approximation. For the example case, differences up to
8% were found.
Several simulation codes of varying degree of sophistication of the SI engine
combustion process have been developed and applied to predict engine performance
over the past years. Multi-zone models are useful when the objective is to evaluate a
large range of conditions, perform parametric studies and/or predict optimum engine
settings. The main drawback of this kind of modeling is presence of calibration
199