High temperature oxidation of residual oil pyrolysis intermediates for modeling gasification and combustion processes

Abstract

Developing chemical kinetic models for residual oil pyrolysis, gasification, and combustion is very challenging due to the large number of components and molecular complexity. This study provides experimental data for model development and validation for two residual oils, heavy fuel oil (HFO) and vacuum residual oil (VRO). This study aims to identify and quantify the HFO and VRO pyrolysis intermediates and validate an oxidation chemical kinetic model of the pyrolysis intermediates to provide data for future residual oil model development using hybrid chemistry (HyChem) and functional groups for mechanism development (FGMech) approaches. The pyrolysis experiments were conducted in a bench-scale tubular reactor at atmospheric pressure and a temperature of 1273 K. Detailed compositions of the yields from the pyrolysis of HFO and VRO were analyzed using gas chromatography-flame ionization detection (GC-FID) for the gas yields and gas chromatography-mass spectrometry/flame ionization detection (GC–MS/FID) for the liquids. Elemental analysis was conducted for the solid residuals. The experiment results show similar pyrolysis products from HFO and VRO. A surrogate of major components of the gas products and representatives of benzene and naphthalene derivatives (major compounds identified in liquid products) of the liquid products was formulated and its chemistry was studied by measuring ignition delay times (IDTs) in a shock tube. IDT measurements were conducted for stoichiometric and rich (ϕ = 1 and 3) mixtures, pressures of 20 and 40 bar, and diluents of nitrogen and carbon dioxide. Brute force IDT sensitivity analyses were used to study the effect of pressure, equivalence ratio and diluents on the reactivity of the mixture.