The co-combustion of torrefied municipal solid waste and coal in bubbling fluidised bed combustor under atmospheric and elevated pressure
Janusz Lasek, Krzysztof Głód, Krzysztof Słowik
Abstract
Municipal solid waste (MSW) is considered a valuable energy source that can be applied as a secondary (co-combustion) or even primary fuel in a power plant. Torrefaction of MSW led to significant benefits related to reduced chlorine and mercury content. The aim of this paper is to investigate the co-combustion of torrefied municipal solid waste and coal in a bubbling fluidised bed combustor under atmospheric and elevated pressure. Torrefaction of pelletised MSW was carried out using a rotary kiln reactor under inert atmosphere (N2) and synthetic flue gas (mixture of CO2 – ∼11 v.%, O2 – ∼4,35 v.%, and N2– as balance). The pelletisation was carried out using a pelletiser with the rotating rollers in contact with the matrix. The pressurised co-combustion of hard coal and MSW (5% and 15% by weight) was carried out under a total pressure of 3 bar and a temperature bed of 850 °C. The main component of the experimental setup was a fluidised bed combustor (bubbling regime). The increase in pressure in the combustion chamber caused significant benefits in terms of the emission of gaseous pollutants. Lower emissions of NO (by ∼56%) and SO2 (by ∼35%) were observed for pressurised combustion.