Heating process characteristics and kinetics analysis of oil sludge in different atmospheres

Abstract

The thermal treatment of oil sludge involves lots of complex and parallel reactions. Detailed analysis about such a process is difficult and limited. Therefore, the combustion and pyrolysis characteristics of a few representative sludge samples were studied through TG-FTIR at different atmospheres in this work. As it is found there is much difference. The oil sludge from Shengli Oil Field contains less moisture and more oil composition compared with that from Liaohe Oil Field. This indicated that the sludge from Shengli Oil Field can be effectively converted into fuels or primary chemicals. Besides, oxygen has a very serious impact on the thermal conversion process of oil sludge. Ambient conditions with an increase of oxygen concentration can oxide the oil sludge at low temperature range; What’s more, different oxygen concentrations distinguished the maximum weight loss rate and its corresponding temperature. The FTIR analyses of the gaseous products from the combustion and pyrolysis processes showed that CO, CO₂, CH₄, H₂O and some volatile organic compounds (e.g. aldehydes and carboxylic acids) are the main thermal degradation compounds. The composition of gaseous compounds changed with oxygen concentration. Specifically, CO₂ accounted for a larger proportion with the increase of oxygen concentration. Obtained dynamic parameters along with the pyrolysis and combustion processes were hard to find regularly. Nevertheless, the apparent activation energy in third stage in which the major weight loss is the decomposition of char increased as the oxygen concentration increased.

Keywords: Oil sludge, TG-FTIR, kinetics mode, differential thermal analysis