Pyrolysis of oil sludge with calcium-containing additive

• Slow pyrolysis  of oil sludge in presence of calcium oxide has been performed.
•  Liquid and gaseous products rich on hydrocarbons with low sulfur content        have been obtained.
• Transformation of mineral matter during pyrolysis has been investigated.
• Increase of polyaromatic hydrocarbons content during pyrolysis has been observed.

The focus of recent research is the utilization of oil sludge as a potential source of hydrocarbons via pyrolysis with the presence of calcium oxide as an additive. Pyrolysis of oil sludge was studied by thermogravimetry and in a laboratory-scale reactor. Results obtained by both methods are consistent. Formation of char, common for slow pyrolysis was very limited. A possible explanation could be in the reaction of calcium sulfate with char which leads to the consumption of carbon and formation of CaS. Oil sludge produced a large amount of oil rich on aliphatic compounds with a higher calorific value of about 42 MJ kg−1 and low sulfur content. A large increase in polyaromatic hydrocarbons during the pyrolysis was observed. Precursors of polyaromatic hydrocarbons were identified in the gas phase.