Abstract:
Converting municipal solid waste (MSW) into valuable feedstocks, such as refuse-derived
fuel (RDF), is a sustainable method according to the concept of waste management hierarchy. A
heterogeneous composition with a good calorific value and lower emissions allows RDF to be
used for energy recovery purposes. We have earlier analyzed the generation and thermochemical
characteristics of the MSW produced in Kazakhstan. This work aims to study the combustion
characteristics in terms of emissions and ash composition to evaluate the possibility of RDF co-firing
with Ekibastuz coal. In particular, RDF is blended with high ash bituminous coal (Ekibastuz coal)
and co-fired in the laboratory scale bubbling fluidized bed reactor (BFB) at a bed temperature of
850 C. The co-firing tests of RDF to coal samples were conducted under various proportions to
analyze flue gas compositions. Experiments were carried in the presence of bed material (sand),
and the fuel particles were fed in batch mode into the hot riser. The BFB reactor had a height of
760 mm and internal diameter of 48 mm. The gaseous products in the flue gas were analyzed by
FTIR spectrometry (Gasmet Dx4000). Ash composition was examined by XRD, XRF, SEM, and PSD.
The results showed that a high RDF content decreased SO2 emissions to 28 ppm, while it negatively
affected NOx release to 1400 ppm, owing to excess air. The emissions of gases from different blended
samples and mineral transformations were investigated and discussed in this study.