On the Products from the Pyrolysis of Heavy Fuel and Vacuum Residue Oil

Abstract

Incorporating unconventional fuel sources into the global energy mix is necessary to meet increasing energy demand. One attractive option is the gasification of residual fuels, such as heavy fuels, which produce clean combustible gases. Pyrolysis is the first step in the gasification process, so its understanding can help in the development of the gasification process. The information on the pyrolysis products can serve the development of chemical kinetics mechanisms for gasification of heavy fuels for their efficient utilization. In this study, pyrolysis of heavy fuel oil (HFO) and vacuum residue oil (VRO) is reported. Prior to the pyrolysis experiments, these fuels were characterized for proximate analysis, elemental and trace metal composition. The pyrolysis experiments were conducted in a wide temperature range of 400–1000 °C in a customized tubular furnace-based reactor. A two-stage condensation system was used to collect the condensable fraction evolved from the pyrolysis of HFO and VRO and non-condensable gases were collected in Tedlar® bags. Both liquid and gaseous products were characterized using a gas chromatography (GC)-mass spectrometry (MS)-flame ionization detector (FID) and Fourier transform–ion cyclotron resonance–mass spectrometer (FT-ICR-MS) to understand the presence of different types of compounds. The identified compounds were classified as benzene derivatives, naphthalene derivatives, polycyclic aromatic hydrocarbons, saturated and unsaturated hydrocarbons and sulfur-containing compounds. In order to better understand the liquid fraction, the heavy fraction (with high molecular weight) which could not be analyzed and identified in GC/MS-FID was analyzed in FT-ICR-MS. This shed significant insights on the deconstruction of HFO and VRO. Twenty lighter hydrocarbons ranging from C1-C5 were identified and quantified in the pyrolysis vapors of both fuels.