Acid Neutralization by Marine Cylinder Lubricants Inside a Heating Capillary: Strong/Weak-Stick Collision Mechanisms

Base nanoparticles are present in marine cylinder lubricants (MCLs) for controlling cylinder corrosive wear by neutralizing combustiongenerated acids. A portion of the surfactants stabilizing these nanoparticles may have dynamic properties, upon which strong/weakstick collisions are proposed to drive the interaction between base particles and acid drops in oil media. Neutralization of sulfuric acid droplets (150-200 (mu)m in diameter) by MCL samples (with a base number of BN = 70 mg KOH/g oil) was performed inside a heatingcapillary microreactor at 23-27, 110-140, and 140-170 °C. The progress of reactions was recorded in real time through a videomicroscopy system and quantified by image analysis. Among four directly observed reaction phenomena, three had never been seen in previous research. These reaction behaviors support the theory of strong/weak-stick collisions and supplement our knowledge to help us better understand the acid neutralization in oil and to propound new strategies for improving the acid-neutralizing performance of overbased detergents.