Kicherer et al. [77] reported that the emissions of SO2 also
decreased as the straw quantity was increased. This was
mainly due to dilution, although for the straw, the SO2
capture due to the presence of CaO and MgO can also be
considered. However, Kicherer et al. [77] found in their
experiments that the emissions of HCl, dioxins and furans
increased with increase in the quantity of straw. The
increase in the emissions of dioxins and furans may be
attributed to three factors. First, straw contains significantly
more Cl and less sulphur than coals. Secondly, due to the
high content of volatiles, the presence of straw may lead to
high concentrations of CO in the flue gas during co-firing.
Thirdly, coal ash may have a considerable amount of Cu.
The presence of low S/Cl ratio in the fuel, high CO concentration
in the flue gas and Cu is important for the de novo
synthesis of dioxins and furans [79].