Combustion studies of poultry litter alone or mixed with peat by 50% on weight basis were undertaken in an atmospheric bubbling
fluidised bed. Because of high moisture content of poultry litter, there was some uncertainty whether the combustion could be sustained on
100% poultry litter and as peat is very available in Ireland; its presence was considered to help to improve the combustion. However, the
results showed that, as long as the moisture content of poultry litter was kept below 25%, the combustion did not need the addition of peat.
The main parameters that were investigated are (i) moisture content, (ii) air staging, and (iii) variations in excess air levels along the
freeboard. The main conclusions of the results are (i) combustion was influenced very much by the conditions of the fuel supply, (ii) the
steady fuel supply was strongly dependent on the moisture content of the poultry litter, (iii) temperature appeared to be still very influential in
reducing the levels of unburned carbon and hydrocarbons released from residues, (iv) the air staging in the freeboard improved combustion
efficiency by enhancing the combustion of volatiles released from residues in the riser and (vi) NOx emissions were influenced by air staging
in the freeboard. Particles collected from the bed and the two cyclones were analysed to determine the levels of heavy metals and the
leachability tests were carried out with ashes collected to verify whether or not they could safely be used in agricultural lands.
q 2002 Published by Elsevier Science Ltd.