• Waste Management Technologies

carbon dioxide emission is a serious environmental issue that humankind must face soon. One of the promising technologies for reducing global CO2 emissions is oxy-fuel combustion (OFC) technology, which belongs to the carbon capture methods. OFC involves the use of oxygen and recirculated flue gas as an oxidizer in the combustion process. Application of oxy-fuel combustion in waste incineration can result in negative CO2 emission since some part of the carbon in municipal solid waste is biogenic. Such technology is often described as BECCS or Bio-CCS and it has attracted the attention of scientists recently. In addition to easier CO2 capture, oxy-fuel combustion of municipal solid waste offers other advantages, such as reduced flue gas volume, increased combustion temperature, and the possibility of retrofitting existing incineration plants. In the present paper, studies of oxy-fuel combustion of waste materials, in particular, municipal solid waste and sewage sludge are presented and summarized.

Oxy-fuel combustion involves the replacement of air as an oxidant into high purity oxygen, usually above 95 vol%, and recirculated flue gas. Consequently, produced flue gas stream contains mainly carbon dioxide and water vapor that can be easily removed by condensation. It was reported that ignition delay increased and flame speed decreased during oxy-combustion due to higher heat capacity of CO2 and lower O2 diffusivity in CO2. Besides, many attempts have been made aimed at estimating the emission of pollutants during oxy-fuel combustion. Studies showed that under oxy-fuel combustion (a) emission of NOx, SO2 and CO can be reduced, however, it highly depended on oxygen concentration in O2/CO2 mixture (with higher amount of oxygen, pollution emission decreased), (b) a big impact on gas emission had a type of fuel and (c) emissions differed since volumetric flue gas flow rate was reduced and flue gas stream was recycled.