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TRANSCRIPT
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MAN B&W Diesel A/S, Copenhagen, Denmark
Contents:
MAN B&W Diesel A/S, Copenhagen, Denmark
Contents:
MAN B&W Diesel A/S, Copenhagen, Denmark
Contents:
MAN B&W Diesel A/S, Copenhagen, Denmark
Contents:
MAN B&W Diesel A/S, Copenhagen, Denmark
Contents:
MAN B&W Diesel A/S, Copenhagen, Denmark
Contents:
MAN B&W Diesel A/S, Copenhagen, Denmark
Contents:
MAN B&W Diesel A/S, Copenhagen, Denmark
Contents:
MAN B&W Diesel A/S, Copenhagen, Denmark
Contents:
MAN B&W Diesel A/S, Copenhagen, Denmark
Contents:
Thermo Efficiency System (TES)for Reduction of Fuel Consumption and CO 2 Emission
Introduction ........................................................................... 3
Description of the Thermo Efficiency System ...................... 4
- Power concept and arrangement ...................................... 4
- Main engine performance data ......................................... 5
- Exhaust gas boiler and steam systems ............................ 6
Obtainable Electric Power Production ofthe Thermo Efficiency System ............................................. 8
- Exhaust gas turbine output.................................................. 8
- Exhaust gas and steam turbine generator output single pressure .................................................... 8
- Exhaust gas and steam turbine generator output dual pressure ....................................................... 10
- Payback time of the Thermo Efficiency System ............... 10
Summary ................................................................................ 13
References ............................................................................ 13
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Thermo Efficiency System (TES)for Reduction of Fuel Consumption and CO 2 Emission
Introduction
Following the trend of required higheroverall ship efficiency since the first oilcrisis in 1973, the efficiency of the mainengines has increased and, today, thefuel energy efficiency is about 50%.
This high efficiency has, among others,led to a correspondingly lower exhaustgas temperature after the turbochargers.
Even though a main engine fuel energyefficiency of 50% is relatively high, theprimary objective for the shipowner isstill to lower the total fuel consumptionof the ship and, thereby, to reduce theCO 2 emission of his ship.
Today an even lower CO 2 emission canbe achieved by installing a ThermoEfficiency System. However, the maindemand for installation of a Thermo
Efficiency System is that the reliabilityand safety of the main engine/ship op-eration must not be jeopardised.
As an example, the heat balance diagramfor the nominally rated 12K98ME/MCengine (18.2 bar) of the standard high-efficiency version is shown in Fig. 1a.Fig. 1b shows an example based onthe Thermo Efficiency System, valid fora single-pressure steam system, to-
gether with the corresponding figuresfor a dual-pressure steam systemshown in parenthesis.
The primary source of waste heat of amain engine is the exhaust gas heatdissipation, which accounts for abouthalf of the total waste heat, i.e. about
25% of the total fuel energy. In thestandard high-efficiency engine version,the exhaust gas temperature after theturbocharger is relatively low, and justhigh enough for production of the ne-cessary steam for a ships heating pur-poses by means of the exhaust gasfired boiler.
However, a main engine with changedtiming and exhaust gas bypass which
redistributes the exhaust gas heat fromhigh amount/low temperature to lowamount/high temperature increasesthe effect of utilising the exhaust gasheat, but at the same time may slightlyreduce the efficiency of the main engineitself. Such a system is called a ThermoEfficiency System (TES).
Shaft power output 49.3%
Lubricating oilcooler 2.9%
Jacket water cooler 5.2%
Exhaust gas25.5%
Air cooler 16.5%
Heat radiation0.6%
Fuel 100%
(171 g/kWh)
12K98ME/MC Standard engine version
SMCR : 68,640 kW at 94.0 r/min
ISO ambient reference conditions
Fig. 1a: Heat balance diagram of the nominally rated 12K98ME/MCengine of the standard engine version operating at ISO ambient
reference conditions and at 100% SMCR
Fig. 1b: Heat balance diagram of the nominally rated 12K98ME/MCengine in Thermo Efficiency System (TES) version operating atISO ambient reference conditions and at 100% SMCR
Fuel 100%(171 g/kWh)
Heat radiation0.6%
Air cooler 14.2%
Exhaust gas andcondenser 22.9% (22.3%)
Jacket water cooler 5.2%
Lubricating oilcooler 2.9%
El. power production of TES 4.9% (5.5%)
Gain = 9.9% (11.2%)
Shaft power output 49.3%
12K98ME/MC with TESSMCR : 68,640 kW at 94.0 r/minISO ambient reference conditionsTES : Single pressure (Dual pressure)
Total power output 54.2% (54.8%)
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Description of the ThermoEfficiency System
Power concept andarrangement
The Thermo Efficiency System (TES)consists of an exhaust gas fired boilersystem, a steam turbine (often called aturbo generator), an exhaust gas tur-
bine (often called a power turbine) anda common generator for electric powerproduction. The turbines and the gen-erator are placed on a common bed-plate. The system is shown schemati-cally in Fig. 2a, and the arrangement of the complete turbine generating set asproposed by Peter Brotherhood isshown in Fig. 2b.
The exhaust gas turbine is driven by apart of the exhaust gas flow, which by-passes the turbochargers. The exhaust
gas turbine produces extra outputpower for electric power production,which depends on the bypassed ex-haust gas flow amount.
When a part of the exhaust gas flow isbypassed the turbocharger, the totalamount of air and gas will be reduced,and the exhaust gas temperature afterthe turbocharger and bypass will increase.
This will increase the obtainable steam
production from the exhaust gas firedboiler.
The exhaust gas bypass valve will beclosed for engine loads lower than about50% SMCR, which means that the ex-haust gas temperature will be reducedwhen operating below 50% SMCR.
The power output from the exhaust gasturbine is transmitted to the steam tur-bine via a reduction gear (see Figs. 2aand 2b) with an overspeed clutch, which
is needed in order to protect the exhaustgas turbine from overspeeding in casethe generator drops out.
The total electric power output of the TES which reduces the ships fuel costs is only a gain provided that it can re-place the power output of other electricpower producers on board the ship.Otherwise, a shaft power motor con-nected to the main engine shaft could
be an option, as also shown in Fig. 2a,but this extra system is rather expensive.
In general (without a shaft power motorinstalled), when producing too muchelectric power, the (high pressure) su-perheated steam to the steam turbineis controlled by a speed control governorthrough a single throttle valve, whichmeans that the surplus steam is dumpedvia a dumping condenser. When thegenerator is operating in parallel withthe auxiliary diesel generators, the gov-
Main engine
Exhaust gas receiver Shaft motor/generator
Diesel generators
Switchboard
Emergencygenerator
Superheatedsteam
Exh. gas boiler
Turbo-chargers
Generator, AC alternator
Reductiongearbox
Steamturbine
Reduction gear with overspeedclutch
LPHP
Exh. gasturbine
Steam for heatingservices HP
LP
Fig. 2a: Power concept for the Thermo Efficiency System
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ernor operates in the normal way togive correct load sharing.
Main engine performance data
The exhaust gas bypass and turbineare available with the following approx.effects, compared with a standardhigh-efficiency main engine versionwithout an exhaust gas bypass:
Open exhaust gas Parameters bypass for exhaust
gas turbine
Power output of exhaust gas tur- bine at 100% SMCR, up to +4.6% SMCR power
Reduction of total exhaust gas amount, approx. -13%
Total increase of mixed exhaust gas temperature after bypass, up to +50C
Increased fuel consumption from 0.0% to +1.8%
The mixed exhaust gas temperature be-fore the exhaust gas boiler, and valid forthe TES and based on ISO ambient ref-erence conditions, is shown as a functionof the engine load in Fig. 3. When oper-
ating under higher ambient air tempera-tures, the exhaust gas temperature will behigher (about +1.6C per +1C air), andvice versa for lower ambient air tempera-tures.
Fig. 2b: Arrangement of the complete turbine generating set as proposed by Peter Brotherhood Ltd
40
C
% SMCR50 60 70 80 90 100
250
Exhaust gas temperatureafter exh. gas bypass
Exh. gas bypass
closed open
Main engine shaft power
200
350
300
Tropical
ISO
Winter
ISOTropical
Winter 25 C air / 25 C c.w.45 C air / 36 C c.w.
15 C air / 36 C c.w.
Ambient reference conditions:
Fig. 3: Exhaust gas temperature after exhaust gas bypass for a main engine with TES
Generator, AC alternator
Reductiongearbox
Steam turbineReduction gear withoverspeed clutch
Exh. gasturbine
Approx. dimensionsreferring to a12K98ME/MC:
Length: 10 metres
Breadth: 3.5 metres
Weight: 58 tons withoutcondenser
Weight: 75 tons withcondenser
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The increased fuel consumption of themain engine depends on the actualmaximum firing pressure (P max ) used.
The P max used for TES will normally beincreased compared with a standardengine and thereby an increase of thespecific fuel oil consumption can beavoided when using TES.
Exhaust gas boiler and steamsystems
The exhaust gas boiler and steam tur-bine systems analysed in this paper arebased on the two types below:
1. Single-pressure steam system The simple single-pressure steam system is only utilising the exhaust gas heat. See the process diagram in Fig. 4 and the corresponding tem- perature/heat transmission diagram in Fig. 5. The steam drum from the
oil fired boiler can also be used in- stead of a separate steam drum.
Fig. 5: Temperature/heat transmission diagram of an exhaust gas boiler with single-pressuresteam system valid for a main engine with TES and operating at 85% SMCR/ISO
Fig. 4: Process diagram for the Thermo Efficiency System single-pressureexhaust gas boiler system with a single-pressure steam turbine
0 40
C
60 80 1000
50
100
Temperature
Heat transmission20
150
200
250
300
Feed-water
Ambient air
Steam/water
7 bar abs/165 CSaturatedsteam
%
Superheatedsteam
min 20 C
A B C
Exh. gas boiler sections:. Superheater. Evaporator. Preheater
A
CB
Exh. gas
Exh. gas
Sat. steamfor heating
services
Condenser
Steamturbine
Feedwaterpump
Circ. pump
Preheater
Evaporator
Superheater
Exhaust gas
Exh. gas boilersections:
Surplusvalve
Steamdrum
Hot well
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Fig. 6: Process diagram for the Thermo Efficiency System dual-pressureexhaust gas boiler system with a dual-pressure steam turbine
Fig. 7: Temperature/heat transmission diagram of an exhaust gas boiler with dual-pressure steam system valid for a main engine with TES and operating at 85% SMCR/ISO
0 40
C
60 80 100
0
50
100
Temperature
Heat transmission20
150
200
250
300
Feedwater preheatedby alternativeWHR sources
Ambient air
Steam/water 10 bar abs/180 C
SaturatedHP steam
%
Superheated
HP steam
min 20 C
A B C
Exh. gas boiler sections:. HP-superheater . HP-evaporator . HP-preheater . Possible LP-superheater . LP-evaporator
ABCDEExh. gas
ED
4 bar abs/144 C
min 15 C
Superheated LP steam
Exh. gas
HP-steamfor heating
services
Condenser
Steamturbine
Feedwaterpump
HP
LP
Alternative WHRsources for feedwaterpreheating
LP-steam drum
HP-steam drum
HP-circ. pump
LP-circ. pump
LP-Evaporator
HP-Preheater
LP-Superheater
HP-Evaporator
HP-Superheater
Exhaustgas
HP LP
Exh. gas boilersections:
Surplusvalve
Hot well
2. Dual-pressure steam systemWhen using the dual-pressure steamsystem, it is not possible to install anexhaust gas low-pressure preheatersection in the exhaust gas boiler, be-cause the exhaust gas boiler outlettemperature otherwise would be toolow and increase the risk of wet (oily)soot deposits on the boiler tubes.
The more complex dual-pressure
steam system, therefore, needssupplementary waste heat recovery(WHR) sources (jacket water andscavenge air heat) for preheating of the feedwater which, of course, willincrease the obtainable steam andelectric power production of TES.See the process diagram in Fig. 6and the corresponding temperature/ heat transmission diagram in Fig. 7.
If no alternative waste heat recoverysources are used to preheat thefeedwater, the low pressure (LP)steam may be used to preheat thefeedwater, involving an about 16% re-duction of the total steam production.
The available superheated steam usedfor the steam turbine is equal to thesurplus steam after deduction of thesaturated steam needed for heatingservices.
The exhaust gas boiler has to be desig-ned in such a way that the risk of sootdeposits and fires is minimised, Ref. [1].
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Obtainable Electric PowerProduction of the ThermoEfficiency System
Exhaust gas turbine output
The exhaust gas bypass for the exhaustgas turbine has a bypass gas amountof approx. 12% of the total exhaust gasamount at 100% SMCR. This bypass-gas
amount led through the exhaust gasturbine will typically produce an availablepower output of max. 4.6% of the SMCRpower when running at 100% SMCR.The corresponding electric power out-put will be somewhat lower because of generator and gear losses.
At part load running of the main engine,the power output will be reduced byapproximately the square root of theengine load.
As an example, the maximum availablepower output of the exhaust gas turbinevalid for a nominally rated 12K98ME/MC(18.2 bar) engine is shown in Fig. 8, asa function of the engine load.
Exhaust gas and steamturbine generator output single pressure
The single-pressure steam system is asystem where all heat recovered comesfrom the exhaust gas heat only, whichmakes it relatively simple, see Figs. 4and 5.
As low gas temperatures (risk of conden-
sed sulphuric acid) and low gas veloci-ties (risk of soot deposits) through theexhaust gas boiler may have a deterio-rating effect on the boiler, Ref. [1], wehave, in our studies, selected an exhaustgas boiler designed for a single-pressuresteam system of minimum 7 bar abs(6 bar g) steam pressure (165C), andminimum 20C pinch point. The super-heated steam temperature is about270C. The steam turbine is a multi-stage single-pressure condensing type.
The alternator/generator is driven bothby the steam turbine and the exhaustgas turbine.
As an example valid for the nominallyrated 12K98ME/MC (18.2 bar) engineoperating at ISO ambient referenceconditions, we have calculated the steamproduction and the electric power pro-duction of TES, see Figs. 10 and 11.
The total electric power production in %of the main engine shaft power outputis also shown as a function of the engineload, see Fig. 9.
The results for operation at 85% SMCRare shown in Fig. 14, together with thecalculated ISO ambient temperature basedresults for three other main engine types.
The corresponding results based ontropical ambient temperature conditionsare shown in Fig. 15. However, it shouldbe emphasised that it is probably morerealistic to use the ISO ambient tem-peratures as the average ambient tem-peratures in worldwide operation. InFig. 16, the ISO based total electricpower production at 85% SMCR is alsoshown as a function of the main enginesize measured in SMCR power.
Fig. 8: Expected available power output of exhaust gas turbine for a12K98ME/MC with SMCR = 68,640 kW x 94 r/min
Fig. 9: Expected electric power production in % of the main engine shaft power output valid for a 12K98ME/MC with Thermo Efficiency System (TES) and based on ISO ambient reference conditions
30 40
kW
% SMCR50 60 70 80 90 1000
500
1,000
1,500
2,000
2,500
3,000
3,500
Available power output of exhaust gas turbine
Exh. gas bypassclosed open
Main engine shaft power % SMCR50 60 70 80 90 1000
Main engine shaft power
1
2
3
4
5
6
7
89
10
11
Steam turbine
Exhaustgas turbine
Main engine 12K98ME/MCSMCR = 68,640 kW at 94 r/min
ISO amb. cond.
Single press.
Dual press.
%
12
13
Electric power production of TESrelative to the main engine power output
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Fig. 10: Expected steam production of an exhaust gas boiler with
single-pressure steam system valid for main engine 12K98ME/MCwith TES and based on ISO ambient reference conditions
Fig. 11: Expected electric power production of the Thermo Efficiency
System (TES) with a single-pressure steam system valid for mainengine 12K98ME/MC and based on ISO ambient reference conditions
Fig. 13: Expected electric power production of the Thermo Efficiency System (TES) with a dual-pressure steam system valid for main engine12K98ME/MC and based on ISO ambient reference conditions
kg/h
90 1000
5,000
10,000
Obtainable steam production
Main engine shaft power 40
15,000
20,000
25,000
30,000
% SMCR
35,000
50 60 70 80
Exh. gas bypassclosed open
Superheated steamfor steam turbine
12K98ME/MC with TES (single press.)SMCR = 68,640 kW at 94 r/minISO amb. cond. Total steamproduction
90 1000
1,000
2,000
Main engine shaft power40
3,000
4,000
5,000
6,000
% SMCR
7,000
50 60 70 80Exh. gas bypassclosed open
Exhaust
gas turbine
12K98ME/MC with TES (single press.)SMCR = 68,640 kW at 94 r/minISO amb. cond.
Steam turbine
Total el.production
kWElectric power production
8,000
90 1000
1,000
2,000
Main engine shaft power 40
3,000
4,000
5,000
6,000
% SMCR
7,000
50 60 70 80Exh. gas bypass
closed open
Exhaustgas turbine
12K98ME/MC with TES (dual press.)SMCR = 68,640 kW at 94 r/minISO amb. cond.
Steam turbine
Total el.production
kWElectric power production
8,000
Fig. 12: Expected steam production of an exhaust gas boiler with adual-pressure steam system valid for main engine 12K98ME/MCwith TES and based on ISO ambient reference conditions
90 1000
5,000
10,000
Main engine shaft power40
15,000
20,000
25,000
30,000
% SMCR
35,000
50 60 70 80
Exh. gas bypassclosed open
12K98ME/MC with TES (dual press.)SMCR = 68,640 kW at 94 r/minISO amb. cond. Total steam
production
kg/hObtainable steam production
40,000
SuperheatedHP steamfor steam turbine
SuperheatedLP steam forsteam turbine
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Exhaust gas and steamturbine generator output dual pressure
Besides the single-pressure steam system,a more complex and more expensivedual-pressure steam system is alsoavailabl e, see Figs. 6 and 7. The highand low steam pressures used areabout 10-11 and 4-5 bar abs (9-10 and3-4 bar g), respectively.
The steam turbine is a multi-stage dual-pressure condensing type. The alternator/ generator is driven both by the steamturbine and the exhaust gas turbine.
Because of the low steam pressure andcorresponding low saturated steam tem-perature (144C/4.0 bar abs), there is noroom for an LP-preheater section in theexhaust gas boiler for feedwater preheat-ing, because the exhaust gas boileroutlet temperature has to be higher thanabout 160-165C in order to avoid sulphu-ric acid corrosion of the boiler outlet.
The feedwater, therefore, has to bepreheated by means of alternative heatsources such as the jacket water andscavenge air cooler heat.
Furthermore, the pinch point should notbe too low (giving low gas velocitiesthrough the boiler) in order to protectthe exhaust gas boiler against sootdeposits and fires.
As an example valid for the nominallyrated 12K98ME/MC (18.2 bar) engineoperating at ISO ambient referenceconditions, we have calculated thesteam production and the electricpower production of the TES, seeFigs. 12 and 13.
The total electric power production in% of the main engine shaft power out-put is also shown as a function of theengine load, see Fig. 9.
The results for operation at 85% SMCRare shown in Fig. 14, together with thecalculated ISO ambient temperaturebased results for three other main en-gine types. The corresponding resultsbased on tropical ambient temperatureconditions are shown in Fig. 15. How-ever, it should be emphasised that it isprobably more realistic to use the ISOambient temperatures as the averageambient temperatures in worldwide op-
eration. In Fig. 16, the ISO based totalelectric power production at 85%SMCR is also shown as a function of the main engine size measured inSMCR power.
Payback time of the ThermoEfficiency System
The payback time of TES depends verymuch on the size of the main engineand the trade pattern (main engine loadand ambient temperatures) of the ship.
Fig. 14: Steam and electric power production and payback time of the Thermo Efficiency System (TES)when operating at 85% SMCR and ISO ambient reference conditions
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When for example operating at tropicalambient conditions, the electric poweroutput of the TES is higher than for ISOambient conditions, which again has ahigher TES output compared with win-ter ambient conditions.
Furthermore, the investment costs perinstalled kW e output of a TES plant arerelatively cheaper the bigger the plant is.
A simple estimation of the average savedfuel costs in service at ISO ambient tem-perature conditions for a 12K98ME/MCwith TES (for single or dual pressure)compared to a standard 12K98ME/MCengine can be found by means of thealready estimated relative TES1/TES2gain of 8.6%/9.8% of the main engineoutput, see Fig. 14.
Based on the average operation in ser-vice at 85% SMCR = 58,344 kW in 280
days a year, SFOC = 0.00017 t/kWhand a fuel price of 160 USD/t the annualmain engine fuel costs of the standard12K98ME/MC engine are as follows:
Fig. 15: Steam and electric power production of the Thermo Efficiency System (TES)when operating at 85% SMCR and tropical ambient conditions
Fig. 16: Expected total electric power production and possible annual fuel cost savings of the Thermo Efficiency System (TES) based on ISO ambient reference conditions and 85%SMCR, shown as a function of the main engine size, SMCR power
80,0000
Size of main engine, SMCR power
20,000 kW40,000 60,000
ISO ambient reference conditions
Normal service : 85% SMCR in 280 days/yearFuel consumption : 0.17 kg/kWhFuel price : 160 USD/t
kW Electric power production
1,000
2,000
3,000
4,000
5,000
6,000
7,000
Steam turbine
Exhaust gas turbine
Dual press.
Single press.
0
0.2
0.4
0.6
0.8
1.0
1.2
mill. USD/yearPossible annual savings of fuel costs
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Fuel costs = 280 days/y x 24 h/day x 0.00017 t/kWh
x 58,344 kW x 160 USD/t = 10,664,000 USD/year
For the single and dual-pressure sys-tems, respectively, the TES gain insaved fuel consumptions will then be asfollows:
TES1 savings = 0.086 x 10,664,000= 917,000 USD/year TES2 savings = 0.098 x 10,664,000
= 1,045,000 USD/year
as shown in Fig. 14.
The similar fuel cost savings valid for theother three cases with smaller main en-gines are also stated in Fig. 14, and incurve form in Fig. 16 as a function of the main engine size, SMCR power.
Based on the extra investment costs of the TES plant (without installation of ashaft power motor on the main engineshaft and minus the investment cost of a normal exhaust gas boiler system) forthe four main engine cases comparedto a standard main engine installation,the estimated payback time found is asstated in Fig. 14, i.e. in principle thesame for the single and dual-pressuresystems. For the 12K98ME/MC engine,the calculated payback time is about
five years.
In Fig. 17, the estimated payback timeof the TES plant is shown as a functionof the main engine size. The payback time is only valid provided all electricpower production savings are used onboard the ship.
It has been assumed that the increasedspecific fuel consumption of the TESmain engine has been avoided by usingan increased firing pressure, P max.
Fig. 17: Estimated payback time of the Thermo Efficiency System (TES) valid for both a single and a dual-pressure steam system
80,0000
Size of main engine, SMCR power20,000 kW40,000 60,000
Normal service : 85% SMCRIn service per year : 280 days/yearFuel consumption : 0.17 kg/kWhFuel price : 160 USD/t
ISO ambient reference conditions
YearPayback time of TES
1
2
3
4
5
6
78
9
10
11
12
13
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Summary
Our calculations indicate that for ISOambient reference conditions, a reduc-tion of the fuel consumption of 8-10%for a single-pressure system is possiblein the normal service range of the mainengine. The larger the engine load, thegreater the possible reduction.
For the more complex dual-pressuresystem, the corresponding reduction isabout 9-11%.
All calculations presume unchangedMTBOs (maintenance time betweenoverhauls) compared to todays expec-tations.
However, if the ship sails frequently incold weather conditions, the electricpower production of the steam turbinewill be reduced, and the above-stated
reduction of fuel consumption and cor-responding reduction of CO 2 emissionmight not be met.
The extra investment costs of the ThermoEfficiency System and the payback of the investment can be obtained bymeans of lower fuel/lube oil costs and,not to forget, the possibility of obtainingadditional freight charters and higherfreight rates, thanks to the green shipimage!
The payback time calculations basedon a large container vessel with a12K98ME/MC as main engine and asaverage operating at 85% SMCR andat ISO ambient reference conditions innormal service during 280 days/yearindicate a payback time of about 5 yearsfor the TES. The payback time is validfor both the single-pressure and thedual-pressure systems, because theincreased electric power productiongain of the dual-pressure system mightcorrespond to about the same relativeincrease of the investment costs com-pared to the single-pressure system.
When selecting the type of Thermo Effi-ciency System, the correspondingly in-volved higher risks for soot deposits andfires of the exhaust gas boiler has to beconsidered, see Ref. [1].
Because of this, but also because of themore simple single-pressure steam boilersystem, MAN B&W Diesel recommendsusing the single-pressure steam system,when installing TES.
Of course, the more complex and moreexpensive dual-pressure steam system,which gives a somewhat higher electricpower output, may also be used inconnection with MAN B&W Dieselstwo-stroke main engine types.
The TES is rather expensive, and relativelymore expensive the smaller the main
engine and the TES are, giving a rela-tively higher payback time. Therefore,the installation of the TES is normallyonly relevant for the large merchant ships,such as the large container vessels.
The TES may be delivered as a packageby Peter Brotherhood (turbines) in co-operation with Aalborg Industries (boiler)and Siemens (generator) or by othermakers.
References
[1] Soot Deposits and Fires in Exhaust Gas Boilers, MAN B&W Diesel A/S, Copenhagen, Denmark, p. 280, March 2004.