Experimental study on fluidised bed combustion of high moisture municipal solid waste

Abstract

The objective of this work was to demonstrate the technical feasibility of a fluidised bed as a clean technology for burning high moisture municipal solid waste (MSW). For co-firing high moisture MSW with coal, the combustion efficiency and the flue gas composition were investigated and compared to burning 100% coal. Different waste materials were burnt: a simulated MSW, vegetable waste and olive oil waste. The maximum moisture content of the simulated MSW that could be burnt was 20% because, at any higher value, the bed temperature was lower than 600 °C, and combustion could not be sustained. The different high moisture content wastes were co-fired with coal to study the effect of moisture and ash content on combustion efficiency. The 60% moisture content simulated MSW at 10%, 15% and 20% concentration by mass were co-fired with coal and it was found that the combustion efficiency decreased ≈12% compared to burning 100% coal (80% and 92%, respectively). For co-firing vegetable waste up to 30% concentration by mass with coal, the combustion efficiencies were ≈90%. It was concluded that the effect of ash content is more pronounced than the moisture content when comparing the combustion efficiency of combustion of simulated MSW and coal to that of vegetable waste and coal. Both the vegetable waste and simulated MSW have the same moisture content (60%), but the ash content of the vegetable waste is lower than that of the simulated MSW, 5% ash content compared to 26% ash content. This conclusion is also supported by the results of co-firing of olive oil waste with coal. The combustion efficiencies were the same as those of combustion of vegetable waste and coal, 90% combustion efficiency. Again, both olive oil waste and vegetable waste have a similar moisture content and ash content, 60% and 5%, respectively.