Combustion behavior and thermochemical treatment scheme analysis of oil sludges and oil sludge semicokes

The combustion behaviors of three oil sludge samples and their corresponding semicoke prepared from a laboratory-scale pyrolysis/gasification reactor were investigated using a thermogravimetric-differential scanning calorimeter-mass spectrum (TG-DSC-MS) system over the temperature range of 313-1173 K under atmospheric pressure. The obtained results revealed that the combustion process can be divided into five stages, and the interval temperature and mass loss of each stage were given. To explain the combustion characteristics of the oil sludges and semicokes during ignition and subsequent burning in detail, a series of combustion characteristic parameters and the derived comprehensive indexes were determined based on the DTG and DSC results. Both the Starink method and Friedman method were employed to conduct combustion kinetics analysis, and the distribution and mean value of the activation energy were obtained. The emissions of the main combustion products, incomplete combustion products, gaseous pollutants, and oxidizing agent during the combustion process were detected by mass spectrometry. Finally, the product yield from the previous pyrolysis/gasification experiments and the data extracted from the former sections were used to conduct a PCA. The synthetical evaluation results indicated that the comprehensive thermochemical treatment scheme might be a more effective choice for the treatment and recovery of oil sludge. (C) 2018 Published by Elsevier Ltd.