Pumps, marine engineering

Residual fuel oils and heavy marine fuels are composed of high-boiling-petroleum fractions, gas oils and cracked components. Residual and clarified oil streams from the FCC process can contain degraded alumina/silica catalyst fines. These 20- to 70-micron-diameter fines are known to contribute to a variety of problems in fuel injection and combustion systems. In marine engines, excessive injector pump wear, piston ring wear, and cylinder wall wear can all be due to the abrasive action of catalyst fines on these fuel system parts. 

Pipe-hne and marine installations are frequently arranged so that the engine drives all its auxiharies from the crankshaft by means of chains and V belts. But process-plant practice is to have all the auxiliaries independently driven, using standby pumps to minimize engine downtime. 

This type of damage is dealt with comprehensively in Section 8.8. It can be particularly severe in seawater giving rise to cavitation corrosion or cavitation erosion mechanisms, and hence can be a considerable problem in marine and offshore engineering. Components that may suffer in this way include the suction faces of propellers, the suction areas of pump impellers and casings, diffusers, shaft brackets, rudders and diesel-engine cylinder liners. There is also evidence that cavitation conditions can develop in seawater, drilling mud and produced oil/gas waterlines with turbulent high rates of flow. 

Precision—The precision of this test method was determined by statistical analysis of inteilaboratory results. In this study, dilution solvents were limited to xylene or kerosine. Some laboraUnies chose to use Babington-type nebulizers, peristaltic pumps, and background correction. Fourteen laboratories analyz twelve specimens in duplicate. The samples were one gas turbine used oil, four gasoline engine used oils, two truck diesel engine used oils, two marine ei e used oils, SRM 1085 diluted in SRM 1083 (base oil) to contain approximately 40 mg/kg of eleven different metals (this oil also contained 8 mass % of an ethylene-propylene copolymer viscosity index improver), SRM 1085 diluted in SRM 1083 to contain approximately 40 mg/kg of twelve different metals, SRM 1085 diluted in SRM 1083 to contain approximately 2 mg/kg of 12 different metals. 

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