regarding paper explains about uses and management of boil of gases in LNG carriers. it mainly focused on latest duel fuel technology to avoid wastage of LNG boil of gases.

2.  DUAL FUEL:-dual fuel consist either heavy fuel, Marine diesel
or LNG gas which is mostly methane or ethane.
 Dual fuel engine is the modern developed engine used for
marine propulsion which is suitable for heavy fuel oil, marine
diesel as well as LNG gases.

3. WORKING PRINCIPLE:- there are many modern developed dual fuel engine
such as MAN B&W 51/60,WARTSILA 50df,WARTSILA 32df etc.
The cylinder cover is slightly changed for DF engine to accommodate the gas
valve and gas handling block as well as pilot injection valve.

4. WORKING:-
FIRST STAGE
Engine starting is always
in diesel mode.
automatically changes
from fuel oil to gas
operation at load below
80% of full load.
 The exhaust valve is
closed and the gas
admission valve is open,
Gas at a higher pressure
than cylinder pressure
flows into the cylinder.

5. SECOND STAGE
The gas
admission valve
is closed and the
piston moves up
the cylinder
compressing the
gas/air mixture

6. THIRD STAGE
 At just before
TDC a pilot
injector injects a
small amount of
fuel oil into the
cylinder which
starts to burn
and ignites the
gas/air mixture.

7. FOURTH STAGE
The piston is
forced down the
cylinder by
burning &
expanding gas.

8. FIFTH STAGE
The exhaust valve
opens followed by the
scavenge ports. Air
enters the cylinder
pushing out the exhaust
gas.
In the event of gas
supply interruption the
engine transfers from
gas to fuel oil

9. THERMAL EFFICIENCY

11. COMPARISON OF FUEL
S.NO. PROPERTIES HEAVY FUEL
OIL
DIESEL GAS
01 CALORIFIC VALUE(KJ/KG) 42500 48500 55500
02 FLASH POINT(‘C) 65 60 65-68
03 SG 0.9-0.99 0.85 0.82-0.85
04 H.C.RATIO 1.5:1 2.5:1 4:1(METHANE)

12. HFO EFFECT ON ENVIRONMENT

13. GRAPHICAL ANALYSIS

14. COMPARISON OF EMISSION
S. NO. EMISSION HEAVY FUEL GAS
01 NOx 100% 10%-15%
02 COx 100% 80%
03 SOx 100% ELIMINATED
04 SOOT/ASH 100% 1%-2%

15. DUAL FUEL
Advantages
• Reduce NOx, SOx,COx
emission
• Low cost operation
• Long engine life
• Low maintenance
• Corrosion free
• High power weight ratio
Disadvantages
• Tendency of vapor lock
while using light fuel.
• More Chance of leakage.
• Dissipate if rupture occurs.
 storage and handling of
fuel

16. FUTURE
• HFO crisis in 2050.
• Future HFO hard to adopt
IMO regulation(Annex6 tier
3).
• 1 JAN ,2020 IMO required
Sulpher to 0.1% .
• Future HFO will be more
worst.
• Synchronizing with future
IMO regulation.
• Non toxic ,no contamination
• many problem ,one solution

17. ANY QUERY???