certain aromatic some of the asphalts will not be held in solution and trouble may be experienced with fouling of filters and separator
fuels with a high asphaltence content burn relatively slowly when compared with fuels from a paraffinic base crude
Generally the effect of high asphaltence content is similar to the effects of high carbon residue content
The paraffinic series of hydrocarbons have a chain-type molecular
Structure while the nepthenic seris of hydrocarbons have a ring structure.
Asphaltic base crudes and nepthenic base crudes are synonymous terms.
Sulphur is known to cause corrosive wear in cylinder liners but the problem of high sulphur content fuels has been overcome with alkaline cylinder oils.
When high sulphur forms gases having various combinations of sulphur and oxygen.
Hydrogen when burnt creates water in the form of steam vapour.
If at any point in the exhaust system the exhaust gases fall in temperature below their dew point, corrosive acids are fomed.
These acids cause corrosion damage at the place where condensation of the acid vapours occurs
Trouble,manifested by high rates of cylinder liner wear,has been experienced with very low sulphur fuels when used with some of the high alhalinity cylinder lubricants available.
Silica and alumina. These fuel contaminants are very abrasive.If they are not removed when the feul is cleaned in the separator and clarifier they may cause extensive wear of the feul injection equipment in a very short space of time.
Sodium and vanadium.Thesse contaminants are chemically combined with the fuel and cannot be removed by centrifuging.In con junction with each other after combustion they are highly corrosive in the liquid state.If the exhaust valves cannot be operated at a sufficiently low temperature the corrosive product in the liquid state stick to the valve seating surfaces and lead to early problems with gas leakage.
This results in burnt valves and low compression pressures leading a loss of efficiency.