(2013) Journal of Environmental Management_Thermo-chemical process with sewage sludge by using CO₂

Kwon E.E., Yi H., Kwon H.-H.

() Journal of Environmental Management ISSN: 3014797 Vol.128 Issue. Article No. DOI: 10.1016/j.jenvman.2013.05.049

This work proposed a novel methodology for energy recovery from sewage sludge via the thermo-chemical process. The impact of CO₂ co-feed on the thermo-chemical process (pyrolysis and gasification) of sewage sludge was mainly investigated to enhance thermal efficiency and to modify the end products from the pyrolysis and gasification process. The CO₂ injected into the pyrolysis and gasification process enhance the generation of CO. As compared to the thermo-chemical process in an inert atmosphere (i.e., N₂), the generation of CO in the presence of CO₂ was enhanced approximately 200% at the temperature regime from 600 to 900°C. The introduction of CO₂ into the pyrolysis and gasification process enabled the condensable hydrocarbons (tar) to be reduced considerably by expediting thermal cracking (i.e., approximately 30-40%); thus, exploiting CO₂ as chemical feedstock and/or reaction medium for the pyrolysis and gasification process leads to higher thermal efficiency, which leads to environmental benefits. This work also showed that sewage sludge could be a very strong candidate for energy recovery and a raw material for chemical feedstock. © 2013 Elsevier Ltd.