Thermogravimetric study on the Co-combustion characteristics of oily sludge with plant biomass

• Adding biomass to oily sludge could promote the combustion process of oily sludge.
• There existed different interactions between the co-combustion processes.
• The reaction heat of oily sludge or wood combustion were obtained.
• The results can enhance the understanding of oily sludge.

Thermal utilization of oily sludge has attracted increased attention. This work studies the combustion characteristics of oily sludge, and its interaction with biomass as well as the reaction heat during the drying and combustion processes of oily sludge. All the experiments were performed by thermogravimetry. Results showed that the co-combustion process of oily sludge with biomass could be divided into three stages with the increase of the temperature. Different interactions between components of oily sludge and biomass existed at different temperatures. At low temperatures (280–390 °C) the interaction between these two fuels slowed down the combustion process of the mixtures, however, it accelerated the combustion process at high temperatures (390–620 °C). The caloric requirement curves of oily sludge with various water contents were obtained by DSC (differential scanning calorimetry) curves. The reaction heat of oily sludge or biomass combustion was also presented. The results obtained can improve the understanding of oily sludge during the combustion process and consequently can be used to develop more efficient sludge combustion equipment.