Name : The 10th International Conference on Modeling and Diagnostics for Advanced Engine Systems (COMODIA 2022)
Date : July 05, 2022 - July 08, 2022
Officially from 2020, the upper limit of marine fuel sulfur has decreased to 0.5% in mass, leading to numerous bad effects on the engine performance. It is urgently necessary to ensure the stable operation of advanced-optimized engines with low-sulfur heavy fuel oil (HFO) in current shipping. Considering the various processes used to make low-sulfur marine fuel in the refineries, the compositions of low-sulfur HFO are diversified, which significantly affects the engine’s oil supply and lubrication systems, as well as the oil combustion performance. Hence, it is necessary to investigate the complex physicochemical processes of low-sulfur HFOs under high temperature and pressure conditions.
In this study, the spray experiments for low-sulfur HFO were firstly conducted, and the effect of low-sulfurization on the HFO spray macroscopic features is negligible. The ambient temperature shows little effect on the spray tip penetration and spreading cone angle, while the ambient density has a great impact. Under high temperature and pressure conditions, the tip penetration of HFO sprays behaves as a non-evaporating spray in the traditional sense, because the tip of spray is maintaining a certain opaque, and the opacity is sensitive to temperature. it is speculated that the substances leading to opacity are mainly formed by pyrolysis and polymerization of HFO in the environment of high temperature and pressure.
In order to confirm the pyrolysis and polymerization process of low-sulfur HFOs, the gas chromatography, mass spectrometry analysis and thermogravimetric analysis coupled with the spray experimental data were conducted. The results revealed that low-sulfur HFO sprays undergo a series of complex physicochemical process reactions in the inert gas, such as evaporation, pyrolysis and polymerization. A large number of aromatic hydrocarbons and macromolecular alkanes are consumed in high temperature environment, and the strong light absorbing substances similar to black carbon are produced. In the gaseous products, unsaturated olefins account for the main proportion instead of alkanes.
