Visiting Scientist from
TOTAL Group
155 South, 1452 East
380 INSCC
University of Utah
Salt Lake City, Utah 84112-1114
Phone: 801-587-0678
Fax: 801-585-5607
Email:
jpedel[@]ec-lyon.fr
Office: 380 INSCC
Research description
The first step in crude oil refining is the primary distillation. Before splitting into different fractions in the distillation tower, the crude oil is first heated in an atmospheric distillation furnace. These furnaces are powered by special burners which use refinery gas and heavy fuel oils. Because of their low cost, heavy fuel oils are economical alternatives for power generation. However, they contain large amount of nitrogen and sulphur, which forms nitrogen oxides and soot during combustion and causes undesirable pollution.
In the context of stricter environmental regulations, being able to predict heat transfer to the crude oil and pollutants is necessary to establish cost-effective, pollution-abatement strategies. The goal is to simulate an atmospheric distillation furnace with CFD software to predict temperature inside the furnace, heat transfer to the tubes, and NOx and soot emissions. Combustion of heavy fuel oils involves several coupled physical phenomena, and so far numerical simulations are unable to model them accurately. As a result, a validation procedure has been established to evaluate the different models and their sensitivity. In this approach, models for the atomizing process and the heavy fuel-oil combustion are developed and evaluated.
One of the major issues in simulating an industrial furnace supplied with fuel oil is to model the atomization process. Specific atomizers, also called “oil guns”, are used to form the droplet spray. Because of the difficulty in atomizing heavy fuel oil, twin-fluid internal mixing atomizers are typically employed. These nozzles are of a very small scale compared to the furnace, and they involve biphasic flows with high velocities and high pressure, so it is not feasible to simulate the atomization process. Consequently a model to account for the atomizer has been developed. It aims at predicting the droplet size distribution and the initial velocities according to the atomizer characteristics, the working conditions and the fuel properties. The model has been validated with experimental data from the IFRF and was able to describe the spray characteristics in most of the cases.
