Propulsion of 46000 50000 Dwt Handymax Tanker

20
Propulsion of 46,000-50,000 dwt Handymax Tanker

description

Propulsion of 46000 50000 Dwt Handymax Tanker

Transcript of Propulsion of 46000 50000 Dwt Handymax Tanker

Page 1: Propulsion of 46000 50000 Dwt Handymax Tanker

Propulsion of 46,000-50,000 dwtHandymax Tanker

Page 2: Propulsion of 46000 50000 Dwt Handymax Tanker
Page 3: Propulsion of 46000 50000 Dwt Handymax Tanker

Content

Introduction .................................................................................................5

EEDI and Major Ship and Main Engine Parameters........................................6

Energy Efficiency Design Index (EEDI) ......................................................6

Major propeller and engine parameters ....................................................7

46,000-50,000 dwt Handymax tanker .....................................................9

Main Engine Operating Costs – 15.1 knots ................................................. 10

Fuel consumption and EEDI .................................................................. 10

Operating costs .................................................................................... 13

Main Engine Operating Costs – 14.5 knots ................................................. 14

Fuel consumption and EEDI .................................................................. 14

Operating costs .................................................................................... 17

Summary ................................................................................................... 18

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Propulsion of 46,000-50,000 dwt Handymax Tanker

Introduction

The main ship particulars of 46,000-

50,000 dwt Handymax tankers are nor-

mally as follows: the overall ship length

is 183 m, breadth 32.2 m and design/

scantling draught 11.0 m/12.2 m, see

Fig. 1.

Recent development steps have made

it possible to offer solutions which will

enable significantly lower transportation

costs for Handymax tankers (and bulk

carriers) as outlined in the following.

One of the goals in the marine industry

today is to reduce the impact of CO2

emissions from ships and, therefore,

to reduce the fuel consumption for the

propulsion of ships to the widest pos-

sible extent at any load.

This also means that the inherent de-

sign CO2 index of a new ship, the so-

called Energy Efficiency Design Index

(EEDI), will be reduced. Based on an

average reference CO2 emission from

existing tankers, the CO2 emission from

new tankers in gram per dwt per nauti-

cal mile must be equal to or lower than

the reference emission figures valid for

the specific tanker.

This drive may often result in operation

at lower than normal service ship speeds

compared to earlier, resulting in reduced

propulsion power utilisation. The design

ship speed at Normal Continuous Rating

(NCR), including 15% sea margin, used

to be as high as 15.0-15.5 knots. Today,

the ship speed may be expected to be

lower, possibly 14.5 knots, or even lower.

A more technically advanced develop-

ment drive is to optimise the aftbody

and hull lines of the ship – including bul-

bous bow, also considering operation

in ballast condition – making it possible

to install propellers with a larger pro-

peller diameter and, thereby, obtaining

higher propeller efficiency, but at a re-

duced optimum propeller speed.

As the two-stroke main engine is direct-

ly coupled with the propeller, the intro-

Fig. 1: Handymax tanker

5Propulsion of 46,000-50,000 dwt Handymax Tanker

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duction of the ‘Green’ ultra long stroke

G50ME-B9.3 engine with even lower

than usual shaft speed will meet this

drive and target goal. The main dimen-

sions for this engine type, and for other

existing Handymax tanker (and bulk

carrier) engines, are shown in Fig. 2.

On the basis of a case study of a

47,000 dwt Handymax tanker in com-

pliance with IMO Tier II emission rules,

this paper shows the influence on fuel

consumption when choosing the new

G50ME-B engine compared with ex-

isting Handymax tanker engines. The

layout ranges of 6 and 7G50ME-B9.3

engines compared with 6 and 7S50ME-

B9.3 and existing 6 and 7S50ME-C8.2

engines are shown in Fig. 4.

EEDI and Major Ship and Main Engine ParametersEnergy Efficiency Design Index (EEDI)

The Energy Efficiency Design Index

(EEDI) is a mandatory instrument to be

calculated and made as available infor-

mation for new ships contracted after

1 January 2012. EEDI represents the

amount of CO2 in gram emitted when

transporting one deadweight tonnage

of cargo one nautical mile.

For tankers, the EEDI value is essential-

ly calculated on the basis of maximum

cargo capacity, propulsion power, ship

speed, SFOC (Specific Fuel Oil Con-

sumption) and fuel type. However, cer-

tain correction factors are applicable,

e.g. for installed Waste Heat Recov-

G50ME-B9

9,91

5

3,896

1,86

01,

205

S50ME-B9

9,32

0

3,350

1,76

5

1,19

0

S50ME-C8

8,58

6

3,150

1,67

31,

098

Fig. 2: Main dimensions for a G50ME-B9 engine and for other existing Handymax tanker engines

ery systems. To evaluate the achieved

EEDI, a reference value for the specific

ship type and the specified cargo ca-

pacity is used for comparison.

The main engine’s 75% SMCR (Speci-

fied Maximum Continuous Rating)

figure is as standard applied in the cal-

culation of the EEDI figure, in which

also the CO2 emission from the auxil-

iary engines of the ship is included.

According to the rules finally decided

on 15 July 2011, the EEDI of a new ship

is reduced to a certain factor compared

to a reference value. Thus, a ship built

after 2025 is required to have a 30%

lower EEDI than the present reference

figure (2012).

6 Propulsion of 46,000-50,000 dwt Handymax Tanker

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8,500

9,000

9,500

10,000

70 8060 90 100 110 120 130 140 150 160 r/minEngine/propeller speed at SMCR

PropulsionSMCR power

kW

1.05

0.95

7.3 m

0.850.76

0.78

0.65

0.60

0.55

p/d

G50ME-B9.3

S50ME-C8.2

S50ME-B9.3

G50ME-B9.3

S50ME-C8.2

S50ME-B9.3

Power and speed curve for the given propeller diameter d = 6.8 m with different p/d ratios

Power and speed curve for various propeller diameters (d) with optimum p/d ratio

SMCR power and speed are inclusive of:15% sea margin10% engine margin 5% propeller light running

4-bladed FP-propellersd = Propeller diameterp/d = Pitch/diameter ratio Design Ship Speed = 15.0 knDesign Draught = 11.0 m

6.8 m

6.3 m

5.8 m

p/dd

0.72

0.74

Fig. 3: Influence of propeller diameter and pitch on SMCR for a 46,000-50,000 dwt Handymax tanker operating at 15.0 knots

Major propeller and engine parameters

In general, the highest possible pro-

pulsive efficiency required to provide a

given ship speed is obtained with the

largest possible propeller diameter d,

in combination with the corresponding,

optimum pitch/diameter ratio p/d.

As an example, this is illustrated for a

46,000-50,000 dwt Handymax tanker

with a service ship speed of 15 knots,

see the black curve on Fig. 3. The need-

ed propulsion SMCR (Specified Maxi-

mum Continuous Rating) power and

speed is shown for a given optimum

propeller diameter d and p/d ratio.

According to the black curve, the ex-

isting propeller diameter of 5.8 m may

have the optimum pitch/diameter ratio

of 0.72, and the lowest possible SMCR

shaft power of about 9,900 kW at about

131 r/min.

The black curve shows that if a bigger

propeller diameter of 6.8 m is possible,

the necessary SMCR shaft power will

be reduced to about 9,050 kW at about

95 r/min, i.e. the bigger the propeller,

the lower the optimum propeller speed.

If the pitch for this diameter is changed,

the propulsive efficiency will be re-

duced, i.e. the necessary SMCR shaft

power will increase, see the red curve.

The red curve also shows that propul-

sion-wise it will always be an advantage

to choose the largest possible propel-

ler diameter, even though the optimum

pitch/diameter ratio would involve a

too low propeller speed (in relation to

the required main engine speed). Thus,

when using a somewhat lower pitch/

diameter ratio, compared with the op-

timum ratio, the propeller/engine speed

may be increased and will only cause a

minor extra power increase.

7Propulsion of 46,000-50,000 dwt Handymax Tanker

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The efficiency of a two-stroke main en-

gine particularly depends on the ratio of

the maximum (firing) pressure and the

mean effective pressure. The higher the

ratio, the higher the engine efficiency,

i.e. the lower the Specific Fuel Oil Con-

sumption (SFOC).

Furthermore, the higher the stroke/bore

ratio of a two-stroke engine, the higher

the engine efficiency. This means, for

example, that an ultra long stroke en-

gine type, as the G50ME-B9.3, may

have a higher efficiency compared with

a shorter stroke engine type, like an

S50ME-C8.2.

The application of new propeller design

technologies may also motivate use of

main engines with lower rpm. Thus, for

the same propeller diameter, these pro-

peller types can demonstrate an up to

6% improved overall efficiency gain at

about 10% lower propeller speed.

This is valid for propellers with Kappel

technology available at MAN Diesel &

Turbo, Frederikshavn, Denmark.

Hence, with such a propeller type,

the advantage of the new low speed

G50ME-B9.3 engine can be utilised

also in case a correspondingly larger

propeller cannot be accommodated.

0

2,000

4,000

6,000

8,000

10,000

12,000

14,000

60 70 80 90 100 110 120 130 140 150 r/minEngine/propeller speed at SMCR

PropulsionSMCR powerkW

4-bladed FP-propellersconstant ship speed coefficient ∝ = 0.28

SMCR power and speed are inclusive of: 15% sea margin 10% engine margin 5% light running

Tdes = 11.0 m

G50ME-B9.3Bore = 500 mmStroke = 2,500 mmVpist = 8.33 m/s (9.00 m/s)S/B = 5.00MEP = 21 barL1 = 1,720 kW/cyl. at 100 r/min(L1 = 1,860 kW/cyl. at 108 r/min)

M = SMCR (15.1 kn)M1 = 9,960 kW x 127 r/min, 6S50ME-C8.2 (L1)M2 = 9,730 kW x 117 r/min, 6S50ME-B9.3M3 = 9,310 kW x 100 r/min, 6G50ME-B9.3

M’ = SMCR (14.5 kn)M1’ = 8,500 kW x 119 r/min, 6S50ME-C8.2M2’ = 8,310 kW x 110 r/min, 6S50ME-B9.3M3’ = 7,950 kW x 94 r/min, 6G50ME-B9.3

PossibleDprop=6.3 m(= 57.3% of Tdes)

PossibleDprop=6.8 m(= 61.8% of Tdes)

ExistingDprop=5.8 m(= 52.7% of Tdes)

7G50ME-B9.3

16.0 kn

15.5 kn

15.0 kn15.1 kn

14.5 kn

14.0 kn

13.5 kn

100 r/min 108 r/min 117 r/min 127 r/min

7S50ME-B9.3

6S50ME-B9.37S50ME-C8.2

6S50ME-C8.2

6G50ME-B9.3 M1M1’

M3

M3’

M2

M2’

Increased propeller diameterG50ME-B9.3

Fig. 4: Different main engine and propeller layouts and SMCR possibilities (M1, M2, M3 for 15.1 knots and M1’, M2’, M3’ for 14.5 knots) for a 46,000-50,000

dwt Handymax tanker operating at 15.1 knots and 14.5 knots, respectively

8 Propulsion of 46,000-50,000 dwt Handymax Tanker

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46,000-50,000 dwt Handymax tanker

For a 47,000 dwt Handymax tanker, the

following case study illustrates the po-

tential for reducing fuel consumption by

increasing the propeller diameter and

introducing the G50ME-B9.3 as main

engine. The ship particulars assumed

are as follows:

Scantling draught m 12.2

Design draught m 11.0

Length overall m 183.0

Length between pp m 174.0

Breadth m 32.2

Sea margin % 15

Engine margin % 10

Design ship speed kn 15.1 and 14.5

Type of propeller FPP

No. of propeller blades 4

Propeller diameter m target

Based on the above-stated average

ship particulars assumed, we have

made a power prediction calculation

(Holtrop & Mennen’s Method) for dif-

ferent design ship speeds and propel-

ler diameters, and the corresponding

SMCR power and speed, point M, for

propulsion of the Handymax tanker is

found, see Fig. 4. The propeller diame-

ter change corresponds approximately

to the constant ship speed factor α =

0.28 [ref. PM2 = PM1 x (n2/n1)α.

Referring to the two ship speeds of

15.1 knots and 14.5 knots, respective-

ly, three potential main engine types,

6S50MC-C8.2, 6S50ME-B9.3 and

6G50ME-B9.3 and pertaining layout

diagrams and SMCR points have been

drawn-in in Fig. 4, and the main engine

operating costs have been calculated

and described below individually for

each ship speed case.

The layout diagram of the G50ME-B9.3

below or equal to 100 r/min is especially

suitable for Handymax tankers (and bulk

carriers) whereas the speed range from

100 to 108 r/min is particularly suitable

for tankers with limited room for installa-

tion of a large propeller.

The S50MC-C and S50ME-C engines

(127 r/min) have often been used in the

past as prime movers for Handymax

tankers, and the relatively new S50ME-

B9 (117 r/min) has already been installed

in some ships. Therefore, a comparison

between the new 6G50ME-B9.3 and

the existing 6S50ME-C8.2 is of major

interest in this paper.

It should be noted that the ship speed

stated refers to NCR = 90% SMCR in-

cluding 15% sea margin. If based on

calm weather, i.e. without sea margin,

the obtainable ship speed at NCR = 90%

SMCR will be about 0.5 knots higher.

If based on 75% SMCR, as applied for

calculation of the EEDI, the ship speed

will be about 0.2 knot lower, still based

on calm weather conditions, i.e. with-

out any sea margin.

9Propulsion of 46,000-50,000 dwt Handymax Tanker

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Main Engine Operating Costs – 15.1 knots

The calculated main engine examples

are as follows:

15.1 knots

1. 6S50ME-C8.2 (Dprop = 5.9 m)

M1 = 9,960 kW x 127.0 r/min

2. 6S50ME-B9.3 (Dprop = 6.2 m)

M2 = 9,730 kW x 117.0 r/min.

3. 6G50ME-B9.3 (Dprop = 6.7 m)

M3 = 9,310 kW x 100.0 r/min.

The main engine fuel consumption

and operating costs at N = NCR =

90% SMCR have been calculated for

the above three main engine/propeller

cases operating on the relatively high

ship speed of 15.1 knots, as often used

earlier. Furthermore, the corresponding

EEDI has been calculated on the basis

of the 75% SMCR-related figures (with-

out sea margin).

Fuel consumption and EEDI

Fig. 5 shows the influence of the pro-

peller diameter with four propeller

blades when going from about 5.9 m to

6.7 m. Thus, N3 for the 6G50ME-B9.3

with a 6.7 m propeller diameter has a

propulsion power demand that is about

6.5% lower compared with N1 valid for

the 6S50ME-C8.2 with a propeller di-

ameter of about 5.9 m.

0

4,000

6,000

2,000

8,000

10,000

Relative powerreduction

%

Propulsion power demand at N = NCR

kW

0

1

2

3

4

5

6

7

8

9

10

6S50ME-C8.2N1

5.9 m×4

6S50ME-B9.3N2

6.2 m×4

6G50ME-B9.3N3

6.7 m×4Dprop:

8,964 kW

Inclusive of sea margin = 15%

8,757 kW8,379 kW

0%

2.3%

6.5%

Propulsion of 47,000 dwt Handymax Tanker – 15.1 knotsExpected propulsion power demand at N = NCR = 90% SMCR

Fig. 5: Expected propulsion power demand at NCR = 90% SMCR for 15.1 knots

10 Propulsion of 46,000-50,000 dwt Handymax Tanker

Page 11: Propulsion of 46000 50000 Dwt Handymax Tanker

Fig. 6 shows the influence on the main

engine efficiency, indicated by the Spe-

cific Fuel Oil Consumption, SFOC, for

the three cases. N3 = 90% M3 for the

6G50ME-B9.3 has an SFOC of 164.1

g/kWh and almost the same 164.3 g/

kWh for N2 = 90% M2 with 6S50ME-

B9.3 where in both cases for the ME-B

engine is included +1 g/kWh needed

for the Hydraulic Power Supply (HPS)

system.

The 164.1 g/kWh SFOC of the N3 for

the 6G50ME-B9.3 is 2.2% lower com-

pared with N1 for the nominally rated

6S50ME-C8.2 with an SFOC of 167.8

g/kWh. This is because of the great-

er derating potential and the higher

stroke/bore ratio of this G-engine type.

Engine shaft power

16225 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 % SMCR

163

164

165

166

167

168

169

170

171

172

173

174

175

176

177

SFOCg/kWh

178

179

180

N3

N1

N2

M3 6G50ME-B9.3M2 6S50ME-B9.3

M1 6S50ME-C8.2

6.7 m ×46.2 m ×4

5.9 m ×4Dprop

Savingsin SFOC

0%

2.1%2.2%

IMO Tier llISO ambient conditionsLCV = 42,700 kJ/kg

Standard high-loadoptimised engines

For ME-B9.3 engines the fuel consumption (+1g/kWh) for HPS is included.

M = SMCRN = NCR

Propulsion of 47,000 dwt Handymax Tanker – 15.1 knotsExpected SFOC

StandardME-B9.3(with VET)

ME-B9.2(without VET)

(VET = Variable Exhaust valve Timing)

Fig. 6: Expected SFOC for 15.1 knots

11Propulsion of 46,000-50,000 dwt Handymax Tanker

Page 12: Propulsion of 46000 50000 Dwt Handymax Tanker

When multiplying the propulsion power

demand at N (Fig. 5) with the SFOC (Fig.

6), the daily fuel consumption is found

and is shown in Fig. 7. Compared with

N1 for the existing 6S50ME-C8.2, the

total reduction of fuel consumption of

the new 6G50ME-B9.3 at N3 is about

8.6% (see also the above-mentioned

savings of 6.5% and 2.2%).

The reference and the actual EEDI fig-

ures have been calculated and are

shown in Fig. 8 (EEDIref =1,218.8 x

dwt -0.488, 15 July 2011). As can be

seen for all three cases, the actual EEDI

figures are equal to or lower than the

reference figure. Particularly, case 3

with 6G50ME-B9.3 has a low EEDI –

about 92% of the reference figure.

0

1

2

3

4

5

6

7

8

0

10

20

30

40

50

60

70

80

90

100

110

120

Reference and actual EEDICO2 emissionsgram per dwt/n mile Actual/Reference EEDI %

EEDI reference 2012 EEDI actual

Dprop:

6S50ME-C8.2N1

5.9 m ×4

6S50ME-B9.3N2

6.2 m ×4

6G50ME-B9.3N3

6.7 m ×4

6.40 6.42

100%6.40

97%

6.40

5.9192%

6.18

Propulsion of 47,000 dwt Handymax Tanker – 15.1 knotsEnergy Efficiency Design Index (EEDI)75% SMCR: 14.9 kn without sea margin

Fig. 8: Reference and actual Energy Efficiency Design Index (EEDI) for 15.1 knots

15 2

310 4

515 6

720 8

925

30

35

40

10111213141516

Relative saving of fuel consumption

%

Fuel consumptionof main engine

t/24h

IMO Tier llISO ambient conditionsLCV = 42,700 kJ/kg

0 0

36.10t/24h 34.54

t/24h 33.00t/24h

0%

4.3%

8.6%

6S50ME-C8.2N1

5.9 m ×4

6S50ME-B9.3N2

6.2 m ×4

6G50ME-B9.3N3

6.7 m ×4Dprop:

For ME-B9.3 engines the fuel consumption for HPS is included.

Propulsion of 47,000 dwt Handymax Tanker – 15.1 knotsExpected fuel consumption at N = NCR = 90% SMCR

Fig. 7: Expected fuel consumption at NCR = 90% SMCR for 15.1 knots

12 Propulsion of 46,000-50,000 dwt Handymax Tanker

Page 13: Propulsion of 46000 50000 Dwt Handymax Tanker

Fig. 9: Total annual main engine operating costs for 15.1 knots

0

2

4

6

1

3

5

6S50ME-C8.2N1

5.9 m×4

MaintenanceLub. oil

Fuel oil

6S50ME-B9.3N2

6.2 m×4

6G50ME-B9.3N3

6.7 m×4

0

4

8

12

2

6

10

1

5

9

3

7

11

7 14

13

Annual operating costsMillion USD/Year

Relative saving in operating costs

%

Dprop:

0%

4.2%

8.3%

Propulsion of 47,000 DWT Tanker – 15.1 knotsTotal annual main engine operating costs

IMO Tier llISO ambient conditions250 days/yearNCR = 90% SMCRFuel price: 700 USD/t

Million USD

LifetimeYears

0

4

8

12

2

6

10

0 5 10 15 20 25 30–2

Saving in operating costs(Net Present Value)

IMO Tier llISO ambient conditionsN = NCR = 90% SMCR250 days/yearFuel price: 700 USD/tRate of interest and discount: 6% p.a.Rate of inflation: 3% p.a.

N3 6.7 m ×46G50ME-B9.3

N2 6.2 m ×46S50ME-B9.3

N1 5.9 m ×46S50ME-C8.2

Propulsion of 47,000 dwt Handymax Tanker – 15.1 knotsRelative saving in main engine operating costs (NPV)

Fig. 10: Relative saving in main engine operating costs (NPV) for 15.1 knots

Operating costs

The total main engine operating costs

per year, 250 days/year, and fuel price

of 700 USD/t, are shown in Fig. 9. The

lube oil and maintenance costs are

shown too. As can be seen, the major

operating costs originate from the fuel

costs – about 96%.

After some years in service, the rela-

tive savings in operating costs in Net

Present Value (NPV), see Fig. 10, with

the existing 6S50ME-C8.2 used as

basis with the propeller diameter of

about 5.9 m, indicates an NPV saving

for the new 6G50ME-B9.3 engine with

the propeller diameter of about 6.7 m.

After 25 years in operation, the saving

is about 9.6 million USD for N3 with

6G50ME-B9.3 with the SMCR speed

of 100.0 r/min and propeller diameter

of about 6.7 m.

13Propulsion of 46,000-50,000 dwt Handymax Tanker

Page 14: Propulsion of 46000 50000 Dwt Handymax Tanker

Main Engine Operating Costs – 14.5 knots

The calculated main engine examples

are as follows:

14.5 knots

1’. 6S50ME-C8.2 (Dprop = 5.9 m)

M1’ = 8,500 kW x 119.0 r/min

2’. 6S50ME-B9.3 (Dprop = 6.2 m)

M2’ = 8,310 kW x 110.0 r/min.

3’. 6G50ME-B9.3 (Dprop = 6.7 m)

M3’ = 7,950 kW x 94.0 r/min.

The main engine fuel consumption and

operating costs at N’ = NCR = 90%

SMCR have been calculated for the

above three main engine/propeller cas-

es operating on the relatively lower ship

speed of 14.5 knots, which is probably

going to be a more normal choice in the

future. Furthermore, the EEDI has been

calculated on the basis of the 75%

SMCR-related figures (without sea mar-

gin).

Fuel consumption and EEDI

Fig. 11 shows the influence of the

propeller diameter with four propeller

blades when going from about 5.9 m to

6.7 m. Thus, N3’ for the 6G50ME-B9.3

with an about 6.7 m propeller diameter

has a propulsion power demand that

is about 6.5% lower compared with

the N1’ for the 6S50ME-C8.2 with an

about 5.9 m propeller diameter. For

the two ME-B engine cases, an extra

SFOC of +1 g/kWh has been added

corresponding to the power demand

needed for the Hydraulic Power Supply

(HPS) system.

0

4,000

6,000

2,000

8,000

10,000

Relative powerreduction

%

Propulsion power demand at N = NCR

kW

0

1

2

3

4

5

6

7

8

9

10

6S50ME-C8.2N1’

5.9 m×4

6S50ME-B9.3N2’

6.2 m×4

6G50ME-B9.3N3’

6.7 m×4Dprop:

7,650 kW

Inclusive of sea margin = 15%

7,479 kW7,155 kW

0%

2.2%

6.5%

Propulsion of 47,000 dwt Handymax Tanker – 14.5 knotsExpected propulsion power demand at N = NCR = 90% SMCR

Fig. 11: Expected propulsion power demand at NCR = 90% SMCR for 14.5 knots

14 Propulsion of 46,000-50,000 dwt Handymax Tanker

Page 15: Propulsion of 46000 50000 Dwt Handymax Tanker

Engine shaft power

16025 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 % SMCR

161

162

163

164

165

166

167

168

169

170

171

172

173

174

175

176

177

178

SFOCg/kWh179

N3’

N1’

N2’

M3’ 6G50ME-B9.3M2’ 6S50ME-B9.3

M1’ 6S50ME-C8.2

6.7 m ×46.2 m ×4

5.9 m ×4Dprop

Savingsin SFOC

0%

2.0%2.1%

IMO Tier llISO ambient conditionsLCV = 42,700 kJ/kg

Standard high-loadoptimised engines

For ME-B9.3 engines the fuel consumption (+1g/kWh) for HPS is included.

M’ = SMCRN’ = NCR

ME-B9.2(without VET)

StandardME-B9.3(with VET)

(VET = Variable Exhaust valve Timing)

Propulsion of 47,000 dwt Handymax Tanker – 14.5 knotsExpected SFOC

Fig. 12: Expected SFOC for 14.5 knots

Fig. 12 shows the influence on the main

engine efficiency, indicated by the Spe-

cific Fuel Oil Consumption, SFOC, for

the three cases. N3’ = 90% M3’ with

the 6G50ME-B9.3 has a relatively low

SFOC of 161.6 g/kWh compared with

the 165.1 g/kWh for N1’ = 90% M1’ for

the 6S50ME-C8.2, i.e. an SFOC reduc-

tion of about 2.1%, mainly caused by

the greater derating potential and higher

stroke/bore ratio of the G-engine type.

15Propulsion of 46,000-50,000 dwt Handymax Tanker

Page 16: Propulsion of 46000 50000 Dwt Handymax Tanker

The daily fuel consumption is found by

multiplying the propulsion power de-

mand at N’ (Fig. 11) with the SFOC (Fig.

12), see Fig. 13. The total reduction of

fuel consumption of the new 6G50ME-

B9.3 is about 8.5% compared with the

existing 6S50ME-C8.2 (see also the

above-mentioned savings of 6.5% and

2.1%).

The reference and the actual EEDI

figures have been calculated and are

shown in Fig. 14 (EEDIref = 1,218.8

x dwt -0.488, 15 July 2011). As can be

seen for all three cases, the actual EEDI

figures are now somewhat lower than

the reference figure because of the

relatively low ship speed of 14.5 knots.

Particularly, case 3’ with 6G50ME-B9.3

has a low EEDI – about 82% of the ref-

erence figure.

0

1

2

3

4

5

6

7

8

0

10

20

30

40

50

60

70

80

90

100

110

120

Reference and actual EEDICO2 emissionsgram per dwt/n mile Actual/Reference EEDI %

EEDI reference 2012 EEDI actual

Dprop:

6S50ME-C8.2N1’

5.9 m ×4

6S50ME-B9.3N2’

6.2 m ×4

6G50ME-B9.3N3’

6.7 m ×4

6.40

5.7189%

6.40

86%

6.40

5.2682%

5.50

Propulsion of 47,000 dwt Handymax Tanker – 14.5 knotsEnergy Efficiency Design Index (EEDI)75% SMCR: 14.9 kn without sea margin

Fig. 14: Reference and actual Energy Efficiency Design Index (EEDI) for 14.5 knots

1

5 2

3

10 4

5

15 6

7

20 8

9

25

30

35

10

11

1213

14

Relative saving of fuel consumption

%

Fuel consumptionof main engine

t/24h

IMO Tier llISO ambient conditionsLCV = 42,700 kJ/kg

0 0

30.32t/24h 29.05

t/24h 27.75t/24h

0%

4.2%

8.5%

6S50ME-C8.2N1’

5.9 m ×4

6S50ME-B9.3N2’

6.2 m ×4

6G50ME-B9.3N3’

6.7 m ×4Dprop:

For ME-B9.3 engines the fuel consumption for HPS is included.

Propulsion of 47,000 dwt Handymax Tanker – 14.5 knotsExpected fuel consumption at N = NCR = 90% SMCR

Fig. 13: Expected fuel consumption at NCR = 90 SMCR for 14.5 knots

16 Propulsion of 46,000-50,000 dwt Handymax Tanker

Page 17: Propulsion of 46000 50000 Dwt Handymax Tanker

0

2

4

1

3

5

6S50ME-C8.2N1’

5.9 m×4

MaintenanceLub. oil

Fuel oil

6S50ME-B9.3N2’

6.2 m×4

6G50ME-B9.3N3’

6.7 m×4

0

4

8

2

6

1

5

9

6

10

12

11

3

7

Annual operating costsMillion USD/Year

Relative saving in operating costs

%

Dprop:

IMO Tier llISO ambient conditions250 days/yearNCR = 90% SMCRFuel price: 700 USD/t

0%

4.0%

8.2%

Propulsion of 47,000 DWT Tanker – 14.5 knotsTotal annual main engine operating costs

Fig. 15: Total annual main engine operating costs for 14.5 knots

LifetimeYears

0

4

8

2

6

10

0 5 10 15 20 25 30–2

Saving in operating costs(Net Present Value)Million USD

IMO Tier llISO ambient conditionsN’ = NCR = 90% SMCR250 days/yearFuel price: 700 USD/tRate of interest and discount: 6% p.a.Rate of inflation: 3% p.a.

N3’ 6.7 m ×46G50ME-B9.3

N2’ 6.2 m ×46S50ME-B9.3

N1’ 5.9 m ×46S50ME-C8.2

Propulsion of 47,000 dwt Handymax Tanker – 14.5 knotsRelative saving in main engine operating costs (NPV)

Fig. 16: Relative saving in main engine operating costs (NPV) for 14.5 knots

Operating costs

The total main engine operating costs

per year, 250 days/year, and fuel price

of 700 USD/t, are shown in Fig. 15.

Lube oil and maintenance costs are

also shown at the top of each column.

As can be seen, the major operating

costs originate from the fuel costs –

about 96%.

After some years in service, the rela-

tive savings in operating costs in Net

Present Value, NPV, see Fig. 16, with

the existing 6S50ME-C8.2 with the

propeller diameter of about 5.9 m

used as basis, indicates an NPV sav-

ing after some years in service for the

new 6G50ME-B9.3 engine with the

propeller diameter of about 6.7 m. Af-

ter 25 years in operation, the saving is

about 7.9 million USD for N3’ with the

6G50ME-B9.3 with the SMCR speed

of 94.0 r/min and propeller diameter of

about 6.7 m.

17Propulsion of 46,000-50,000 dwt Handymax Tanker

Page 18: Propulsion of 46000 50000 Dwt Handymax Tanker

Summary

Traditionally, super long stroke S-type

engines, with relatively low engine

speeds, have been applied as prime

movers in tankers.

Following the efficiency optimisation

trends in the market, the possibility of

using even larger propellers has been

thoroughly evaluated with a view to us-

ing engines with even lower speeds for

propulsion of particularly tankers (but

also bulk carriers).

Handymax tankers (and bulk carriers)

may be compatible with propellers with

larger propeller diameters than the cur-

rent designs, and thus high efficiencies

following an adaptation of the aft hull

design to accommodate the larger pro-

peller, together with optimised hull lines

and bulbous bow, considering opera-

tion in ballast conditions.

The new ultra long stroke G50ME-

B9.3 engine type meets this trend in

the Handymax tanker (and bulk carrier)

market. This paper indicates, depend-

ing on the propeller diameter used,

an overall efficiency increase of 8-9%

when using G50ME-B9.3, compared

with existing main engine type S50ME-

C8.2 applied so far.

Compared with existing S50MC-C8 or

even S50ME-C7/MC-C7 often used in

the past, the overall efficiency increase

will be even higher when using G50ME-

B9.3.

The Energy Efficiency Design Index

(EEDI) will also be reduced when us-

ing G50ME-B9.3. In order to meet the

stricter given reference figure in the fu-

ture, the design of the ship itself and

the design ship speed applied (reduced

speed) has to be further evaluated by

the shipyards to further reduce the EEDI.

18 Propulsion of 46,000-50,000 dwt Handymax Tanker

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Page 20: Propulsion of 46000 50000 Dwt Handymax Tanker

MAN Diesel & TurboTeglholmsgade 412450 Copenhagen SV, DenmarkPhone +45 33 85 11 00Fax +45 33 85 10 [email protected]

MAN Diesel & Turbo – a member of the MAN Group

All data provided in this document is non-binding. This data serves informational purposes only and is especially not guaranteed in any way. Depending on the subsequent specific individual projects, the relevant data may be subject to changes and will be assessed and determined individually for each project. This will depend on the particular characteristics of each individual project, especially specific site and operational conditions. Copyright © MAN Diesel & Turbo. 5510-0110-02ppr Dec 2012 Printed in Denmark