Bachelor Degree in Maritime Operations (BMO)

Diesel Technology & Emissions

Unit 1: Marine Fuel Oil Team members:

Jannell TohPurunaraj

Celeste YeongDate : 5 July 2006

Briefly describe the relation of marine Briefly describe the relation of marine fuels and ISO8217fuels and ISO8217

ISO 8217ISO 8217 petroleum products- petroleum products- Fuels ( Class F)- specifications of Fuels ( Class F)- specifications of marine fuels.marine fuels.

State the following properties and State the following properties and glossary:glossary:

Fuel DensityFuel Density

Essential for quantity calculation, Essential for quantity calculation, setting purifier, indicating specific setting purifier, indicating specific energy and ignition quality.energy and ignition quality.

ViscosityViscosity

Determines injection and transfer Determines injection and transfer temperature, use in calculating temperature, use in calculating ignition quality.ignition quality.

There are two related measures of There are two related measures of fuel viscosity which are known as fuel viscosity which are known as dynamic and kinematic viscosity.dynamic and kinematic viscosity.

Viscosity IndexViscosity Index

Viscosity IndexViscosity Index (or VI) is a (or VI) is a petroleumpetroleum industryindustry term term

It is a It is a lubricatinglubricating oil oil qualityquality indicator indicator The The viscosityviscosity of liquids decreases as of liquids decreases as

temperaturetemperature increases increases The The viscosityviscosity of a of a lubricantlubricant is closely is closely

related to its ability to reduce related to its ability to reduce frictionfriction

Carbon Residue (Conradson Carbon Residue (Conradson Method)Method)

Indicates the relative carbon forming Indicates the relative carbon forming propensity of an oilpropensity of an oil

It is a It is a lubricatinglubricating oil oil qualityquality indicator indicator The test is a means of determining The test is a means of determining

the residual carbon, etc., left when the residual carbon, etc., left when an oil is burned under specified an oil is burned under specified conditions.conditions.

SulphurSulphur

Sulphur is a naturally occurring Sulphur is a naturally occurring element in crude oil, concentrated element in crude oil, concentrated in the residual components of the in the residual components of the crude oil distillation process.crude oil distillation process.

level of sulphur in the fuel has a level of sulphur in the fuel has a marginal effect on the specific marginal effect on the specific energy.energy.

Flash PointFlash Point

The flash point of a fuel is the The flash point of a fuel is the temperature at which vapour given off temperature at which vapour given off will ignite when an external flame is will ignite when an external flame is applied under specified test conditions.applied under specified test conditions.

A flash point is defined to minimise fire A flash point is defined to minimise fire risk during normal storage and risk during normal storage and handling.handling.

Fire PointFire Point

The The fire pointfire point of a fuel is the of a fuel is the temperature at which it will temperature at which it will continue to burn after ignition for at continue to burn after ignition for at least 5 secondsleast 5 seconds

Self Ignition PointSelf Ignition Point

Self ignition point is the ignition of Self ignition point is the ignition of combustible material without combustible material without initiation by spark or flame when initiation by spark or flame when the material has been raised to a the material has been raised to a temperature at which self temperature at which self sustaining combustion occurs.sustaining combustion occurs.

Pour PointPour Point

The pour point is the lowest The pour point is the lowest temperature at which a marine fuel temperature at which a marine fuel can be handled without excessive can be handled without excessive amounts of wax crystals forming so amounts of wax crystals forming so preventing flow.preventing flow.

Calorific ValueCalorific Value

Heating valueHeating value (or (or calorific valuecalorific value) ) is used to define the amount of is used to define the amount of heatheat released during the released during the combustion of a combustion of a fuelfuel or or foodfood..

Cetane NumberCetane Number

It is a measure of the fuel's It is a measure of the fuel's combustion quality.combustion quality.

Octane NumberOctane Number Octane is measured relative to a Octane is measured relative to a

mixture of isooctane (2,2,4-mixture of isooctane (2,2,4-trimethylpentane, an isomer of trimethylpentane, an isomer of octane) and n-heptane.octane) and n-heptane.

Specific GravitySpecific Gravity

The specific gravity of an oil is the The specific gravity of an oil is the ratio of the weight of unit volume of ratio of the weight of unit volume of the oil to the weight of the same the oil to the weight of the same volume of water.volume of water.

Specific gravity generally gives an Specific gravity generally gives an indication of the viscosity of the oil. indication of the viscosity of the oil. The higher the specific gravity the The higher the specific gravity the higher the viscosity.higher the viscosity.

Ash – SourceAsh – Source

The ash constituents from the The ash constituents from the crude oil are concentrated in the crude oil are concentrated in the residual fuel and this concentration residual fuel and this concentration depends upon the refinery depends upon the refinery processes employed.processes employed.

Fuel Impurities (Vanadium and Fuel Impurities (Vanadium and Sodium) – SourceSodium) – Source

Vanadium is a metal present in all Vanadium is a metal present in all crude oils in an oil soluble form. crude oils in an oil soluble form.

The levels found in residual fuels The levels found in residual fuels depend mainly on the crude oil depend mainly on the crude oil sourcesource

Air/Fuel RatioAir/Fuel Ratio

Air-fuel ratioAir-fuel ratio refers to the refers to the proportion of air and fuel present proportion of air and fuel present during combustion.during combustion.

Injection DelayInjection Delay

Injection Timing Delay decreases Injection Timing Delay decreases NOx emissions by retarding the NOx emissions by retarding the amount of diesel fuel delivered to amount of diesel fuel delivered to the combustion chamber prior to the combustion chamber prior to compressed ignition. Due to the compressed ignition. Due to the decrease in fuel delivered to the decrease in fuel delivered to the combustion chamber, combustion combustion chamber, combustion temperatures are lowered, temperatures are lowered, decreasing associated NOx levels.decreasing associated NOx levels.

Ignition DelayIgnition Delay

The ignition delay period is the The ignition delay period is the interval between injector opening interval between injector opening and the start of ignition.and the start of ignition.

CombustionCombustion

Rapid CombustionRapid Combustion Fuel that has accumulated in the cylinder Fuel that has accumulated in the cylinder

during the delay period before ignition during the delay period before ignition burns rapidly. burns rapidly.

Steady CombustionSteady Combustion combustion has been established in the combustion has been established in the

cylinder, further fuel droplets entering the cylinder, further fuel droplets entering the cylinder will burn as soon as they have cylinder will burn as soon as they have penetrated, heated, vaporized, and mixed, penetrated, heated, vaporized, and mixed, so that the combustion rate lags behind so that the combustion rate lags behind the injection rate by the preparation time.the injection rate by the preparation time.

After Burning PeriodAfter Burning Period

If all fuel has burned cleanly and completely If all fuel has burned cleanly and completely by the end of the steady combustion period, by the end of the steady combustion period, the pressure trace will be smooth through the pressure trace will be smooth through the expansion stroke, and the after burning the expansion stroke, and the after burning period could be neglected. period could be neglected.

Typically, however, there will be some Typically, however, there will be some irregularities reflecting combustion of irregularities reflecting combustion of incompletely burned fuel or of intermediate incompletely burned fuel or of intermediate combustion products, and some delayed combustion products, and some delayed chemical end reactions. It is during this chemical end reactions. It is during this period that soot and other pollutants are period that soot and other pollutants are produced.produced.

What is Engine “Knock”?What is Engine “Knock”?

Knocking occurs when the air-fuel Knocking occurs when the air-fuel mixture autoignites all at oncemixture autoignites all at once..

The explosive reaction causes The explosive reaction causes combustion to stop before the combustion to stop before the optimum timing, causing a optimum timing, causing a decrease in performance.decrease in performance.

AtomisationAtomisation

Atomisation is the splitting up of fuel Atomisation is the splitting up of fuel into very small droplet by fuel injector into very small droplet by fuel injector forcing fuel at high pressure through forcing fuel at high pressure through small atomizing holes. small atomizing holes.

PenetrationPenetration Penetration refers to the distance Penetration refers to the distance

the oil droplets travel into the the oil droplets travel into the combustion chamber before mixing combustion chamber before mixing with the air and igniting.with the air and igniting.

SwirlSwirl Swirl is the movement of

compressed air and fuel within the combustion space before combustion occurs.

TurbulenceTurbulence Turbulence will improve the Turbulence will improve the

mixing of fuel and air effective mixing of fuel and air effective and rapid combustion.and rapid combustion.

Air/Fuel MixingAir/Fuel Mixing

Intimate mixing of the air and the Intimate mixing of the air and the fuel is necessary for complete for fuel is necessary for complete for complete combustion. complete combustion.

This requires a sufficient amount of This requires a sufficient amount of air to burn the fuel droplet air to burn the fuel droplet adequately.adequately.

Excess Air CoefficientExcess Air Coefficient The excess air coefficient λ is the

ratio between the amount of air feed to the engine and the theoretically necessary amount.

Compression RatioCompression Ratio

This is the ratio obtained the ‘Volume at BDC’ by the ‘Volume at TDC’.