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

Fu, Jianzhong; Lu, Yunfeng; Campbell, Curt B.; Papadopoulos, K.

doi:10.1007/s11249-006-9082-z

Cited by 11 publications

(28 citation statements)

References 10 publications

(22 reference statements)

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“…26 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 The adsorption-controlled reaction rate constant expression used in the model simulations, Eq. (13), is based on the video-microscopy single droplet experiments performed by Fu et al, 24 who reported a shrinking rate. The present model considers only consumption of entire droplets.…”

Section: Evaluation Of Model Assumptionsmentioning

confidence: 99%

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

Lejre

Glarborg

Mayer³

et al. 2018

Ind. Eng. Chem. Res.

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Lubrication oil for marine diesel engines contains additives in the form of CaCO 3 -based reverse micelles, which can neutralize condensing H 2 SO 4 , and thereby limit uncontrolled corrosive wear of the piston rings and cylinder liner. In the present work, the neutralization mechanism was studied experimentally and through modeling.Using a mixed flow reactor (MFR), the rate of the acid-base reaction was measured as a function of relevant process parameters. In addition, the competition between CaCO 3 reverse micelles and NaOH droplets for a reaction with H 2 SO 4 droplets in a lube oil emulsion was explored in a batch reactor. For the residence times investigated, the results show that CaCO 3 conversion is significantly reduced when reaching a critically low Ca/S ratio. Furthermore, a mathematical model for the neutralization of H 2 SO 4 droplets by CaCO 3 reverse micelles in lube oil under well-mixed conditions was developed. Both the experimental data and simulations support previous results suggesting that the limiting step in the neutralization mechanism is adsorption of reverse micelles onto the much larger H 2 SO 4 droplets. Using the video-microscopy experiments of Fu et al.1 ), 221-225], it was possible to estimate kinetic parameters for the adsorption-controlled reaction. The model was used to predict conversion of H 2 SO 4 in a lube oil film at the cylinder liner surface for conditions relevant for a full-scale application. Calculations indicated that H 2 SO 4 may reach the liner surface regardless of how well-wetted the surface is.

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Section: Evaluation Of Model Assumptionsmentioning

confidence: 99%

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

Lejre

Glarborg

Mayer³

et al. 2018

Ind. Eng. Chem. Res.

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“…Experimental materials and methods were described in detail in our previous report [26]. One difference of the present work is that multiple acid droplets were injected inside the MCL-filled capillary microreactor and monitored through our video-microscopy system [26,27].…”

Section: Methodsmentioning

confidence: 99%

“…One difference of the present work is that multiple acid droplets were injected inside the MCL-filled capillary microreactor and monitored through our video-microscopy system [26,27]. The success of the experiments requires keeping all the injected acid droplets in view so that the progress of neutralization can be recorded and precisely measured [26] at all stages of the experiments. The disappearing rate of each acid droplet is characterized by radius change with time [26], which includes both the rates of acid neutralization and solubilization.…”

Section: Methodsmentioning

confidence: 99%

“…The success of the experiments requires keeping all the injected acid droplets in view so that the progress of neutralization can be recorded and precisely measured [26] at all stages of the experiments. The disappearing rate of each acid droplet is characterized by radius change with time [26], which includes both the rates of acid neutralization and solubilization. We did not separate these two rates because (i) such combination should also exist in real-engine environments and (ii) the rate of solubilization is about two orders of magnitude slower than that of acid neutralization, which was measured in our previous report [20].…”

Section: Methodsmentioning

confidence: 99%

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Ostwald ripening: a decisive cause of cylinder corrosive wear

Papadopoulos

et al. 2007

Tribol Lett

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Acids formed from fuel combustion and lubricating oil breakdown can promote corrosive engine wear. Using capillary videomicrocopy to investigate the neutralization of sulfuric acid droplets by overbased additives in lubricating oil, we have found that the Ostwald ripening of acid droplets may be a decisive factor of corrosive wear because it prolongs the lifetime of larger acid droplets. This finding provides a new understanding of how acids corrode engine parts, and in particular, why the most corrosive engine wear often occurs at piston top dead center, and may lead to new strategies for engine designs and lubricating oil additives.

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“…The rate of reaction increases with temperature possibly because the number of water droplets increases with temperature by breakup of large droplets, so enhancing the probability of encounter with an OD particle. 15,19,20 The surfactant molecules on the surface of the nanoparticle and the acid droplet can at least partially exchange on 'collision', exposing the CaCO 3 more effectively to the acid and subsequent neutralization.…”

Section: Introductionmentioning

confidence: 99%

Response of Calcium Carbonate Nanoparticles in Hydrophobic Solvent to Pressure, Temperature, and Water

Bodnarchuk

Heyes

Breakspear³

et al. 2015

J. Phys. Chem. C

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Molecular Dynamics (MD) simulations of surfactant-stabilized calcium carbonate, CaCO 3 , nanoparticles in hydrophobic solvent have been carried out to characterize their response to changes in temperature (T) and pressure (P), and also their interaction with trace water and water droplets. The response to increasing temperature and pressure is sensitive to the type of model surfactant, with the sulfonate-stabilized particle, which is the most spherical, showing a weak temperature-pressure dependence, while the sulfurized alkyl phenol (SAP) and salicylate-stabilized particles distort into a more spherical shape with increasing temperature and pressure. The atom-atom radial distribution functions of the core ions reveal consolidation of the calcium carbonate structure with increasing temperature and pressure.The simulations show that the nanoparticles adsorb onto the surface of water droplets through a water bridge transitional mechanism, in agreement with evidence from experimental studies. In the case of the sulfonate surfactant particle, only, a number of surfactant molecules detached from the calcium carbonate core and transferred to the surface of the water droplet. Consequently this type of particle had the greatest interaction with and affinity for water which may explain its rapid neutralization characteristics observed in experiments.The detachment free energy of the sulfonate obtained by potential of mean force (PMF) calculations was the largest of the three, which is consistent with the core being more embedded in the water and less well stabilised on returning to the hydrophobic medium. The salicylate nanoparticle had about half the detachment free energy, which could give rise to a more dynamic equilibrium of attached-to-detached states for this class of nanoparticle.

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

Cited by 11 publications

References 10 publications

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

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

Ostwald ripening: a decisive cause of cylinder corrosive wear

Response of Calcium Carbonate Nanoparticles in Hydrophobic Solvent to Pressure, Temperature, and Water

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