Archive for June 2010
Full text available for CIMAC paper no. 39 2010: Modelling of the oxidation of fuel sulfur in low speed two-stroke engines
In large marine two stroke Diesel engines during combustion of sulfur containing fuel, the sulfur is oxidised to SO2 , mainly, although substantial amounts of SO3 and H2SO4 will form as well. These latter species may cause corrosional wear of the cylinder liner if not neutralised by lube oil additives. Potential attacks is due to either condensation of sulfuric acid on the cylinder liner lube oil film or direct dissolution of oxidised sulfur species in the lube oil film in which reaction with dissolved water may be the source of acidic species. In order to evaluate and predict corrosional wear of the liner material, it is pivotal to have realistic estimates of the distribution/concentration of oxidised sulfur species as well as a reliable model of
formation, transport and destruction of acidic species in the oil film. This paper addresses the former part by invoking a detailed reaction mechanism in order to simulate the oxidation of fuel bound sulfur and predicting the concentration of SO2 as well as the conversion fraction into SO3 and H2 SO4 . The reaction mechanism is coupled to a realistic model of the combustion process in which the air entrainment into the combustion zone is accounted for. The results of the simulation are evaluated with respect to previously applied models as well as existing data on the conversion fraction of SO2 to SO3 and H2 SO4 . The conversion fraction is found to be in a range of 2.6-6.7 %.
A pivotal part for the creation of the above paper has been the usage of the Cantera software for handling thermodynamics and integration of kinetic rate equations.