H.F.O. Heavy fuel oil ( residual, blends & crudes );
D.F.O. Diesel fuel oil or M.D.O. Marine Diesel oil or light fuel oil ( in restricted sense )
1.1.1 Residuals are residues from various rafinery processes;
1.1.2 Blends are fuel oil mixtures of different viscosity to obtain a product of desired viscosity and density.
1.1.3 Crudes: natural mixtures consisting of hydrocarbons + sulphur, nitrogen and / or oxygen derivatives of hydrocarbons.
FUEL OILS
H.F.O. Heavy fuel oil ( residual, blends & crudes );
D.F.O. Diesel fuel oil or M.D.O. Marine Diesel oil or light fuel oil ( in restricted sense )
1.1.1 Residuals are residues from various rafinery processes;
1.1.2 Blends are fuel oil mixtures of different viscosity to obtain a product of desired viscosity and density.
1.1.3 Crudes: natural mixtures consisting of hydrocarbons + sulphur, nitrogen and / or oxygen derivatives of hydrocarbons.
2. FUEL VISCOSITY
Internal resistance of a fluid to relative movement. Oil is more viscous when cold. Viscosity is measured in Redwood Universal, Saybolt Universal, Saybolt Furol and Engler, but most commonly in kinematic cSt.
3. PURPOSE OF THE FUEL OIL SYSTEM
To store, transfer & clean the oil prior to injection.
6.2 Pressure loss alarm indicates a pressure drop below permissible limits.
6.3 Viscosity regulator* controls fuel oil temperature, i.e. viscosity)
6. SAFETY DEVICES
6.1 Low tank level alarm signals that a level in the tank is too low.
6.2 Pressure loss alarm indicates a pressure drop below permissible limits.
6.3 Viscosity regulator* controls fuel oil temperature, i.e. viscosity)
6.4 Pressure regulating valve ensures constant pressure at the fuel main;
6.5 Quick close valves are valves having collapsable briage and may be closed from outside machinery space.
6.6 Emergency remote cut-out switches fitted to the pumps and actuated in case of emergency.
Gear pump rotates at about 40 rpm
Fuel inlet / supply is close to the heater discharge
The fuel is discharged through a capillary tube
The pressure diference between each end of the tube is directly proportional to the viscosity of oil flowing through it.
Pressures are measured with Bourdon tubes and compared to read as viscosity.
Pressures are fed to a differential presure transmitter which can automatically operate the heater control to maintain fuel viscosity within close limits
7. COMBUSTION
8. FACTORS LEADING TO GOOD COMBUSTION
8.1 VISCOSITY
It must be low enough to ensure correct atomisation at the fuel injection. When fuel oil is heatedits viscosity is reduced.
8. FACTORS LEADING TO GOOD COMBUSTION
8.1 VISCOSITY
It must be low enough to ensure correct atomisation at the fuel injection. When fuel oil is heated its viscosity is reduced.
8.2 ATOMISATION
Is splitting up the fuel into very small droplets. The size of a droplet depends upon:
a) the atomizer holes;
b) pressure difference between the fuel pump
c) discharge and that of the compressed air in the combustion chamber.
8.3 PENETRATION
Is the distance the oil droplets travel into combustion space before mixing with air and igniting.
