Environmental Engineering Reference
In-Depth Information
efficiencies. Moreover,
system b
produces very low percentages of inert ashes, about the 3-
4%, compared to 30% of toxic wastes produced by
system a.
For systems
b
and
c
it's important to emphasize the conversion energetic efficiency, that
is 0.98 for the first and 0.68 for the latter, and also the percentage composition of syngas, (see
Figure 10).
System c
offers a cleaner gas compared to
system b,
with high concentrations of hydrogen
and carbon monoxide, and low percentage of nitrogen and negligible sulphur compounds.
Figure 9. Energy efficiencies (expressed in percent) of system a and b.
Figure 10. Percentage composition of syngas.
Despite the sophisticated instruments for the reduction of smokes, from an environmental
point of view, the smokes of
system a
present organic material deriving from uncompleted
combustion or thermic synthesis reaction.
Systems b and c
generate syngas in good
conditions, so they do not give rise to hazardous dioxins and furans. Experimental data
demonstrate that emissions to atmosphere generated by the combustion of the synthetised gas
of
system b and c
are lower than emissions produced by
system a
, especially when it comes to
sulphur, nitrogen and chlorine compounds.