Modelling of Corrosion of Cylinder Liner in Diesel Engines Caused by Sulphur in the Diesel Fuel

Mixed Flow Reactor Experiments and Modeling of Sulfuric Acid Neutralization in Lube Oil for Large Two-Stroke Diesel Engines

“…Consequently, by using a micelle diffusion-controlled reaction rate, no limitation is found for the neutralization reaction. The poor agreement at lower Ca/S ratios confirms that the neutralization reaction is not diffusion-controlled, even with the present value of the diffusion-controlled reaction rate constant, 2.9·10 6 m 3 mol -1 s -1 , which is a significantly smaller value than the value used by Schramm et al39 and van Helden. Model simulations showing conversion of (a) CaCO 3 reverse micelles and (b) H 2 SO 4 droplets as a function of Ca/S by using a micelle diffusion-controlled reaction rate constant and an adsorption-controlled reaction rate constant at three values of H 2 SO 4 radius, .…”

“…In section 3, we conclude that reverse micelle adsorption onto the H 2 SO 4 droplets is most likely the limiting step in the neutralization mechanism at well-mixed conditions, in line with the literature investigations. 21 However, early modeling studies [39][40][41] indicated that the neutralization reaction may be acid diffusion-controlled. In this study, a reaction rate expression that accounts for both micelle diffusion-and adsorption-resistance will be set up for comparison and the rate-limiting step identified.…”

“…The dependence of temperature follows the viscosity temperaturedependency, which is typically a strong function of temperature. 47 The micelle-diffusion controlled reaction rate is first order with respect to each reactant (H 2 SO 4 droplet and CaCO 3 micelle, respectively), and is given by [39][40][41] :…”

“…It is believed that condensed H 2 SO 4 forms a thin film on top of the layer of lube oil film. 7,39 The condensation of H 2 SO 4 occurs in the gas phase just before reaching the lube oil film, where the temperature is lower than in the bulk gas phase. 6,47,48,56 Since no mixing is occurring, transport of CaCO 3 micelles to the H 2 SO 4 happens by diffusion.…”

Modeling the condensation of sulfuric acid and water on the cylinder liner of a large two-stroke marine diesel engine

“…In practice the lube oil film on the liner surface (distributed by the moving piston) serves to hamper corrosion through base additives. Schramm [13] formulated a 1D model of sulfuric acid and base diffusion through the film and reported that the acid is efficiently neutralized. However, deposited acid was based on estimates and the influence of water was not considered.…”