Acid‐neutralizing of marine cylinder lubricants: Measurements and effects of dispersants

Temperature and acid droplet size effects in acid neutralization of marine cylinder lubricants

“…This means the rate (-dr t /dt) of acid neutralization may be significantly increased when a droplet gets smaller than a certain value (CP on its r t -vs.-t curve), after which the curvature of acid droplet may affect the neutralization considerably. These results support the above analysis and agree with Hosonuma and Tamura's report [1] that small-size acid-droplet emulsions had a higher reactivity, and also explain Wu et al result [4] that the initial size of an acid droplet did not influence on the rate of acid neutralization since the droplet size might have not yet reduced to a level corresponding to its change point as we found in the present work. The neutralization of sulfuric acid by overbased detergents in a MCL may result in the growth of crystal calcium sulfate hydrates [10,11] or the shrinking of acid droplets while maintaining their structure, i.e., without crystal growth [10].…”

“…We further assume that every base particle has the same residence time s and takes the same volume of acid t per stick collision since the particles are almost identical. We also ignore the rate of solubilization because it is very slow compared with the rate of acid neutralization [4]. For the desorption-controlled case (s ‡ s d , h = 1), the volume change rate is:…”

“…In the temperature range of 10-30°C, the activation energy for the acid neutralization was relatively low and independent of specific pH indicators being used. In 2000, Wu et al [4], our previous work, reported that initial acid droplet size did not affect the rate of reaction between nitric acid droplets and commercial MCLs by using a video-enhanced capillary microscopy. This seems to contradict with Hosonuma and Tamura's results that the smaller the size of acid emulsions, the higher the reactivity [1].…”

Interfacial Resistance in Solubilization Kinetics

“…The importance of kinetics of solubilization is not confined to commercial detergency, but applies as well to physiological systems such as dissolution of cholesterol by bile salts (7), in cleanup of underground pollutants (16), and in delivery of reactants (17) and drugs (18). Very often, interfacial resistances are seen to be controlling.…”

Microscopic Studies of Calcium Sulfate Crystallization and Transformation at Aqueous–Organic Interfaces

“…CaSO4 micelles are also likely to be within this film, formed from neutralization of the overbased CaCO3 detergent particles by H2SO4, 46,47 and this component plays an important role.…”