engines bergen as - sintef...engine fuel efficiency . exhaust emissions . power management ....
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Engines Bergen AS
Fuel Efficiency and Reliability in LNG propulsion
CIMAC NMA Norway Fall Meeting 2014 Hordvikneset 24.09.2014 / Erlend Vaktskjold
Topics
1. How to save fuel cost and reduce exhaust emissions Fuel prices Engine fuel efficiency Exhaust emissions Power management Variable speed - engine and propeller
2. Reliability Loss of propulsion Limited propulsion control Equipment malfunction or damage 3. Examples of LNG propulsion
2
Fuel Prices – Worldwide 3
Chosen values: LNG 10$/GJ
Sources: MDO: Bunker Index MDO http://www.bunkerindex.com/prices/bixfree_1310.php?priceindex_id=4 LNG: Argus Global LNG: LNG Markets, Projects and infrastructure Volume IX, ISSUE 12, Dec 2013; Volume X, Issue 4, April 2014
MDO 20$/GJ
LNG vs Diesel – Fuel Cost 4
20
25
30
35
40
45
50
0 25 50 75 100
Fuel
Eff
icie
ncy
[%]
Power Output [%]
LNGMDO
0
10
20
30
40
50
60
0 25 50 75 100
Fuel
Cos
t [$/
GJ]
Power Output [%]
LNGMDO
LNG vs Diesel – Exhaust Emissions 5
0
50
100
150
200
250
0 25 50 75 100
CO2
emis
sion
[kg/
GJ]
Power Output [%]
LNGMDO
0
50
100
150
200
250
0 25 50 75 100
CO2
emis
sion
[kg/
GJ]
Power Output [%]
LNGMDO
0
4
8
12
0 25 50 75 100
NO
x em
issi
on [g
/kW
h]
Power Output [%]
LNGMDO
LNG vs Diesel – Exhaust Emissions 6
LNG vs Diesel – in the Engine Room 7
Diesel engine – 20.000h Gas engine – 45.000h
Power Mangement
Multiple engines example – 4 generating sets
8
0
5
10
15
20
25
30
35
0 20 40 60 80 100
Fuel
Cos
t [$/
GJ]
Vessel power demand [%]
Variable speed 9
0
5
10
15
20
25
30
35
0 25 50 75 100
Fuel
Cos
t [$/
GJ]
Power Output [%]
Variable Speed
Fixed Speed
0
20
40
60
80
0 4 8 12 16 20
Fuel
Cos
t [$/
NM
]
Vessel Speed [knots]
Variable Speed
Fixed Speed
Summary Fuel Cost and Emissions 10
• Run on LNG • Run as few engines as possible • Run variable engine speed • Run variable propeller speed • (Use twin screw)
40-60Hz
60Hz
Reliability – Types of Faults 11
Fault type Consquence Mitigation
Loss of propulsion «Let go the anchor!» - Very high robustness
in critical elements - Redundancy
Limited propulsion Out of commercial service (off-hire)
- Robustness - Redundancy??
Equipment malfunction or damage
Maintenance / replacement required
- Robustness - Less equipment /
reduced redundancy
Loss of propulsion 12
Diesel (conventional) LNG (lean burn SI)
Major breakdown …
Minor brakdown Onboard spares available
Rudder control
Pump failure, control failure, leakage, etc Pitch control
Clutch control
Fuel supply Major leak Gas leak SD Block valves (4 off, fail to closed)
Pressure drop in LNG tank
Engine shutdown Safety shutdown (prevent major breakdown)
Governor failure Mechanical backup governor on single engines Electronic governor, no backup
Ignition Self-ignition Ignition sys with spark plugs and pickups
Redundancy on fuel supply and engine IS required!
Limited propulsion 13
Diesel (conventional) LNG (lean burn SI)
Rudder backup control Pitch backup control Clutch backup control Air-Fuel control / limit Smoke limiter
Black smoke in case of failure Electronic governor and
actuator Gas pressure control NA Electro-penumatic control
Combustion knocking NA Slow down alarm <40%
Reliability Summary – Loss of, or Limited, Propulsion 14
• Run on LNG • Run as few engines as possible • Run variable engine speed • Run variable propeller speed • (Use twin screw)
40-60Hz
60Hz
(need frequency converter)
(tied to engine speed)
Examples of LNG propulsion
Fjord 1 / E39 Halhjem/Sandvikvåg + Arsvågen/Mortavika • 5 ferries since 2006, 1 more 2013
• Gas – electric propulsion, 2 – 4 main gensets per vessel
• Diesel backup gensets
• 10.000 – 12.000 port calls / year with no incidents
Torghatten Nord / Lofoten • 4 ferries since 2013
• Gas mechanical propulsion – 1 main engine per vessel
• Diesel genset backup through PTI on gearbox
• An unacceptable number of incidents
15
Examples of LNG propulsion
Fjord Line – «Danskebåten» • 2 cruise ferrys 2013
• Gas-mechanical propusion
• 4 main engines, 2 propellers
• Loss of propusion incidents relating to LNG tank pressure drop
Bukser and Berging • 2 tugs operating at Kårstø gas terminal 2014
• Gas-mechanical propusion
• 2 main engines, 2 propellers
• No loss of propulsion incidents
Conclusions LNG propulsion 17
• Significant fuel cost savings • Significant emission reduction - both local and global impact • LNG propulsion is more complex - fuel storage, evaporation and pressure control - engine ignition and air-fuel control ⇒ Individual subsystem is likely to be less reliable System reliability must be restored by overall system design
18 Questions – Comments ?