PRODUCT BULLETIN

Delo 1000 Marine

Marine & Stationary Diesel Engine Oil

Delo 1000 Marine is a lower alkaline reserve (12Base Number) trunk piston engine oil

(TPEO). Delo 1000 Marine is designed for use in medium-speed trunk piston engines

burning distillate fuels with sulfur content up to 1.5% in marine or stationary service.

APPLICATIONS

Medium-speed trunk piston engines in stationary power generation

Medium-speed trunk piston engines (marine service)

Engine reduction gears

PERFORMANCE STANDARDS

Approved by major manufacturers for use in their medium-speed engines

BENEFITS

Maintains power output

The detergent/dispersant additive system provides control of high temperature

deposits in areas such as the undercrown of the piston and the piston ring belt area,

enabling piston rings to function efficiently.

Prolongs oil life

Base Number (BN) level and superior alkalinity retention characteristics maintain

sufficiently high BN under all service conditions to ensure corrosive acids formed by

the combustion of fuel sulfur are effectively neutralized, thereby minimizing liner wear.

Efficient purifying system performance

Excellent water separation characteristics enable water to be centrifuged out with

essentially no loss of additive.

KEY PROPERTIES

(2010.07)

This bulletin was prepared in good faith from the best information available at the time of issue. While the values and characteristics are considered representative, some variation, not affecting performance, can be expected. It is the responsibility of the user to ensure that the products are used in the applications for which they are intended. Produced by GS Caltex Corporation.

SAE Grade 30 40

Viscosity

mm²/s @ 40℃ 96.0 137

mm²/s @ 100℃ 11.0 14.0

Viscosity Index 99 98

FZG Fail Load Stage 11 11

Sulfated Ash, m % 1.6 1.6

Base Number,mg KOH/g 12 12

Zinc, m % 0.06 0.06

Page

Fuel Oil Quality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Analysis Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Fuel Oil Stability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Fuel Oil Treatment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Centrifuging Recommendations . . . . . . . . . . . . . . . . . . . . . . . . . 7

High Density Fuels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Fuel Sampling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Supplementary Fuel Oil Treatment . . . . . . . . . . . . . . . . . . . . . . . 9

Fuel Oil System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Operational Aspects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Off�Spec. Fuels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Lubricating Oil Qualities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Cylinder Oil, Low Speed Diesels. . . . . . . . . . . . . . . . . . . . . . . . . 12

Performance Verification of Cylinder Oils . . . . . . . . . . . . . . . . . . . 14

Fuels and Lubes for Stationary Two�stroke

MAN B&W Engines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Contents:

Operation on Heavy Residual FuelsGuidelines for Fuels and LubesMAN B&W Diesel Two�stroke Engines andMAN B&W Diesel Four�stroke Holeby GenSets

Fuel Oil Quality

MAN B&W Diesel’s two�stroke lowspeed diesel engines and MAN B&WHoleby four�stroke diesel GenSets aredesigned to operate in accordancewith the unifuel principle, i.e. with thesame fuel for both main and auxiliarydiesels.

For guidance on purchase, referenceis made to ISO 8217, BS6843 and toCIMAC recommendations regardingrequirements for heavy fuel for dieselengines, edition 2001. From these, themaximum accepted grades are RMH55 and K55. The mentioned ISO andBS standards supersede BS MA 100,in which the limit is M9.

For reference purposes, an extractfrom the relevant standards and speci�fications is shown in Table 1.

Based on our general service experience,and as a supplement to the above�mentioned standards, MAN B&W issuea guiding fuel oil specification, shown inTable 2.

In both tables the data refers to fuel oilsas delivered to the ship, i.e. beforeonboard cleaning. Fuel oils within thelimits of this specification have, to theextent of their commercial availability,been used with satisfactory results inMAN B&W two�stroke low speed dieselengines and four�stroke Holeby typeauxiliary diesel engines.

3

DesignationCIMACA 10

CIMACB 10

CIMACC 10

CIMACD 15

CIMACE 25

CIMACF 25

CIMACG 35

CIMACH 35

CIMACK 35

CIMACH 45

CIMACK 45

CIMACH 55

CIMACK 55

Related to ISO 8217 (96): FRMA10

RMB10

RMC10

RMD15

RME25

RMF25

RMG35

RMH35

RMK35

RMH45

RMK45

RMH55

Characteristic Dim. Limit

Density at 15 oC kg/m3 max. 950 975 980 991 991 1010 991 1010 991 1010

Kinematic viscosityat 100 oC 1) cSt

2) max. 10 15 25 35 45 55

min. 4) 6 15

Flash point oC min. 60 60 60 60 60 60

Pour point oC max.06 3) 24 30 30 30 30 30

Carbon residue %(m/m) max. 12 14 14 15 20 18 22 22 22

Ash %(m/m) max. 0.10 0.10 0.10 0.15 15 0.15 0.15

Total sedimentafter ageing

%(m/m) max. 0.10 0.10 0.10 0.10 0.10 0.10

Water %(v/v) max. 0.50 0.80 1.0 1.0 1.0 1.0

Sulphur %(m/m) max. 3.5 4.0 5.0 5.0 5.0 5.0

Vanadium mg/kg max. 150 300 350 200 500 300 600 600 600

Aluminium andsilicon

mg/kg max. 80 80 80 80 80 80

1) Approximate equivalent viscosities (for information only):

Kinematic viscosity (cSt) at 100 oC 6 10 15 25 35 45 55

Kinematic viscosity (cSt) at 50 oC 22 40 80 180 380 500 700

Sec. Redwood I at 100 oF 165 300 600 1500 3500 5000 7000

Table 1: Residual marine fuel standards

2) 1 cSt = 1 mm2/sec

3) Applies to region and season in whichfuel is stored and used, (upper value winterquality, bottom value summer quality)

4) Recommended value onlyMay be lower if density is also lower

Guiding specification (maximum values)

Density at 15 oC *Kinematic viscosity

at 100 oCat 50 oC

Flash pointPour pointCarbon residueAshTotal sedimentafter ageingWaterSulphurVanadiumAluminium + Silicon

kg/m3

cStcStoCoC

%(m/m)%(m/m)

%(m/m)%(v/v)

%(m/m)mg/kgmg/kg

< 1010*

< 55< 700> 60< 30< 22< 0.15

< 0.10< 1.0< 5.0< 600< 80

Equal to ISO 8217/CIMAC � H55

* Provided automatic clarifiers are installedm/m = mass v/v = volume

Table 2: Guiding fuel oil specification

Operation on Heavy Residual FuelsGuidelines for Fuels and LubesMAN B&W Diesel Two�stroke Engines andMAN B&W Diesel Four�stroke Holeby GenSets

It should be noted that current analysisresults do not fully suffice for estimatingthe combustion properties of fuel oils.

This means that service results coulddepend on oil properties which are notknown beforehand. This applies espe�cially to the tendency of the fuel oil toform deposits in combustion chambers,gas passages and turbines.

As mentioned, the data refers to thefuel as supplied, i.e. before the onboardcleaning.

On account of their limited commercialavailability, relatively little service experi�ence has been accumulated on fuelswith data exceeding the following:

Viscosity………….………450 cSt/50°CCarbon residue….. . ………………18%Sulphur…………......…………..……4%Vanadium………...…………400 mg/kg

If fuels exceeding these data are to beused, the engine performance shouldbe closely watched.

If fuel oils exceeding the data in Table2, especially with regard to viscosityand density, are to be used, the enginebuilder or MAN B&W should be con�tacted for advice regarding possiblefuel oil system changes, ref. ‘Supple�mentary Fuel Oil Treatment’ section.

Analysis Data

ViscosityViscosity cannot be considered a qual�ity criterion in its own right for fuel oils,and is stated only for handling reasons(pumps, preheaters and centrifuges).

DensityDensity is related to the fuel quality dueto the fact that fuels derived from ex�tensive refinery processing are left witha higher carbon content, are more aro�matic, and are thus heavier. Therefore,fuels with high density are also high incarbon residue and asphalt.

The ignition and combustion charac�teristics of higher density fuels mightbe inferior. A low viscosity, togetherwith a high density, might indicate poorignition quality (see Ignition quality). Thewater separation ability of the fuel oil isensured by limiting the density for rea�sons of centrifuging, as stated in thespecification.

Density is normally measured at highertemperatures, and the density at 15°Cis calculated on the basis of tables which,depending on their origin, date of issue,and the data on which they are based,could give slightly differing densities at15°C.

Whereas the limit of 991 kg/m3 mustbe observed when traditional centrifuges(before 1985, purifier – clarifier) areused, 1010 kg/m3 is accepted providedthat modern centrifuges capable ofhandling fuel of this density are installed.

Flash pointThe flash point limit is set as a safeguardagainst fire only.

SulphurThe corrosive effect of sulphuric acidduring combustion is counteracted byadequate lube oils and temperaturecontrol of the combustion chamber

walls. The sulphur content has a negli�gible effect on the combustion process.

Carbon residueThe carbon residue is measured asConradson Carbon or as Microcarbon.Fuels with high carbon residue contentcould cause increased fouling of thegasways, necessitating more frequentcleaning, especially of the turbochargerand exhaust gas boiler.

Some changes in combustion, requir�ing adjustment of maximum pressuresfor reasons of economy, could also beattributed to a high carbon residuecontent. Part of the carbon residuesrepresents asphaltenes.

The effect of asphaltenes on the com�bustion process is similar to that of thecarbon residue. Asphaltenes also affectthe fuel oil lubrication properties. In ex�treme cases, high asphalt content couldlead to fuel pump sticking. Fuels with ahigh content of asphaltenes may tendto emulsify with water.

WaterWater in the fuel should be removed bycentrifuging the fuel before use. Thisapplies especially to salt water, thesodium content of which can result indeposits on valves and turbochargers.If water cannot be removed, homogen�ising after centrifuging is recommended.

AshAsh represents solid contaminants aswell as metals present in the fuel in sol�uble compounds (vanadium). Part ofthe ash could be catalyst particles fromthe refining process.

Such particles are highly abrasive.Solid ash should be removed to thewidest possible extent by centrifuging,and cleaning can be improved byinstalling a fine filter after the centrifuge(e.g. 5�10µm).

4

Vanadium and sodiumVanadium is present in the fuel in solu�ble compounds and, consequently,cannot be removed.

Vanadium, in combination with sodium,may lead to exhaust valve corrosion andturbocharger deposits. According toISO 8217 and CIMAC this can occurespecially if the weight ratio of sodiumto vanadium exceeds 1:3, and especiallyin the case of a high vanadium content.

MAN B&W have limited data to show thatthe level of sodium and vanadium in com�bination, and in this ratio, have led to theabove�mentioned complications on MANB&W engines.

For lower contents of sodium and va�nadium, the weight ratio is consideredof less importance (for vanadium contentless than 150 mg/kg).

Sodium is normally present in the fuelas a salt water contamination and may,as such, be removed by centrifuging.Sodium can also reach the engine inthe form of airborne sea water mist.

Vanadium deposits can be so hard thatthey can cause extensive damage to theTC nozzle ring and turbine wheel. Theonly way to remove vanadium depositsis to disassemble the components anderase the deposits mechanically.

Magnesium, either present in the fuelor introduced via additives can, tosome extent, increase the melting pointof the vanadium, thus preventing theformation of deposits.

Aluminium and siliconThe limit to aluminium and silicon hasbeen introduced in order to restrict thecontent of catalytic fines, mainly Al2O3and SiO2, in the oil. 80 mg Al and Sicorresponds to up to 170 mg Al2O2and SiO2.

Catalytic fines give rise to abrasive wear,and their content should, therefore, bereduced as far as possible by centrifug�ing the fuel oil before it reaches the en�gine, and cleaning can be improved byinstalling a fine filter after the centrifuge(e.g. 5�10µm).

Ignition qualityNormally applied analytical data for fueloil contain no direct indication of ignitionquality, neither do current specificationsand standards. Although not an impor�tant parameter for engines with highcompression ratios, high density incombination with low viscosity might,as mentioned, be an indication of poorignition quality.

In a few cases (less than five), we haveobserved that the fuel had such poorignition quality that the engines couldnot operate properly. When this is said,only off�spec. fuel oils which have beenmixed with non�fuel products are ex�pected to have properties that can re�sult in an ignition delay which can affectthe performance of MAN B&Wtwo�stroke and four�stroke engines.

Ignition quality can to some extent bepredicted by calculations based on vis�cosity and density, using formulas is�sued by the oil industry (CCAI by Shellor CII by BP).

However, tests carried out on the MANB&W research engine in Copenhagenhave shown that the CCAI and CII donot in all situations give a correct pic�ture of a fuel’s ignition quality. Bettermethods are now available.

Tests performed together with fuel ana�lysing institutes give better indicationsof the ignition qualities of the differentfuels. Test instruments utilising a con�stant volume combustion technologyhave been developed and are currentlybeing used for marine fuel testing at anumber of fuel laboratories and build�ers of marine diesel engines worldwide.

By the use of calibration fuels, a re�corded ignition delay can be convertedinto an instrument�related CetaneNumber. In addition, the Rate of HeatRelease is presented, reflecting the ac�tual heat release process and, thus, thecombustion quality of the fuel tested.

The test results reflect the differencesin ignition and combustion propertiesof diesel engine fuels resulting fromvariations in the chemical compositionof the fuels being tested.

However, these test results do not re�flect the functions of the actual enginecombustion in the diesel engine, be�cause the tests were conducted atlower pressures and temperatures.

With the modern high compression ra�tio engines, the denoted differences inthe fuel, both good and bad, are not atthe level indicated by the test results.The cetane number in an ignition qual�ity test might, as such, only provide anindication as to why the vessel hasproblems in service.

5

Fuel Oil Stability

Fuel oils are produced on the basis ofwidely varying crude oils and refineryprocesses. Due to incompatibility, suchfuels can occasionally tend to be un�stable when mixed, for which reason

mixing on board should be avoided tothe widest possible extent.

A mixture of incompatible fuels in thetanks can result in rather large amountsof sludge being taken out by the centri�fuges or even lead to centrifuge blocking.

Inhomogeneity in the service tank canbe counteracted by re�circulating thecontents of the tank through the centri�fuge. This will have to be carried out atthe expense of the benefits derivedfrom a low centrifuge flow rate as men�tioned below.

6

Boosterpump

Circulationpumps

Heater

Overflow valveadjusted to 4 bar

Diesel oilservice tank

Deck

Automatic deaerating valve

Auxiliaryengine

Supplypumps

Auxiliaryengine

Diesel oilHeavy fuel oilHeated pipe with insulation

From centrifuges

Main engine

Fuel oildrain tank

To jacket water cooling pump suction

Auxiliaryengine

Common fuel oil supply unit

Full flowfilter, 50 m

Heavy fuel oilservice tank

Venting box

7�8 bar

Drain fromfuel pumps

Fig. 1: Pressurised fuel oil system

Fuel Oil Treatment

Fuels supplied to a ship must betreated on board before use. Detailedinformation on fuel oil system layoutcan be found in the CIMAC Recom�mendations issued in 1987 concerningthe design of heavy fuel treatmentplants for diesel engines. Practically allfuel specifications refer to fuel as sup�plied and, as such, serve primarily aspurchasing specifications. Furthermore,the data in a standard fuel analysisserves to adjust the onboard treatmentand is actually of little use to the opera�tor when referring to the engine opera�tional data. Hence the basic designcriterion is that engines shall be capa�ble of accepting all commercially avail�able fuel oils, provided that they areadequately treated on board.

For this purpose, a well�designed fueloil treatment system is a must. Generalminimum recommendations for the lay�out of such a system have been speci�fied and should be complied with inorder to ensure proper treatment of thefuel permitted by the guiding specifica�tion. The operation of the fuel prepara�tion system is the responsibility of theoperator. Good results require both thecorrect system and the correct opera�tion of the system.

The fuel oil system consists of a clean�ing plant (comprising centrifuging) anda pressurised fuel oil system.

Fig. 1 shows the pressurised fuel oilsystem common for MAN B&W mainand GenSet engines.

CentrifugingRecommendations

Fuel oils, whether HFO or DO, shouldalways be considered as contaminatedupon delivery and should therefore bethoroughly cleaned to remove solid aswell as liquid contaminants before use.The solid contaminants in the fuel aremainly rust, sand, dust and refinerycatalysts. Liquid contaminants aremainly water, i.e. either fresh water orsalt water.

Impurities in the fuel can cause damageto fuel pumps and fuel valves, and canresult in increased cylinder liner wearand deterioration of the exhaust valveseats. Also increased fouling of gaswaysand turbocharger blades could result fromthe use of inadequately cleaned fuel oil.

Effective cleaning can only be ensuredby using a centrifuge. We recommendthat the capacity of the installed centri�fuges should, at least, accord to thecentrifuge maker’s specifications. Toobtain optimum cleaning, it is of the ut�most importance that the centrifuge isoperated with as low a fuel oil viscosityas possible, and that the fuel oil is al�lowed to remain in the centrifuge bowlfor as long as possible.

A sufficiently low viscosity is obtainedby operating the centrifuge preheaterat the maximum allowable temperaturefor the fuel concerned. See Fig. 2.

For fuels above 180 cSt/50°C it is es�pecially important that the highest pos�sible temperature, 98°C, is maintainedin the centrifuge oil preheater.

7

Rate of flow, related to rated capacity of centrifuge

100

90

80

70

80

60

40

20

Separation temperature

15 25 45 75 100 130 cSt/80 oC

30 60 80 180 380 700 cSt/50 Co

200 400 600 1500 3500 7000 sec RI/100 Fo

Log.scales

%

%

Fig. 2: Centrifuge makers’ capacity specification

The fuel is kept in the centrifuge aslong as possible by adjusting the flowrate through the centrifuge so that itcorresponds to the amount of fuel re�quired by the engine without excessiverecirculation. Consequently, the centri�fuge should operate for 24 hours a dayexcept during necessary cleaning.

Centrifuges with separate feed pumpswith a capacity matched to the engineoutput are to be preferred.

Taking today’s fuel qualities into con�sideration, the need for maintenance ofthe centrifuges should not be underes�timated.

On centrifuges equipped with adjustingscrews and/or gravity discs, their correctchoice and adjustment is of special im�portance for the efficient removal of water.

The centrifuge manual states whichdisc or screw adjustment should bechosen on the basis of the density ofthe fuel.

The normal practice is to have at leasttwo centrifuges available for fuel clean�ing purposes, operating in serial or par�allel mode.

Results from experimental work on thecentrifuge treatment of today’s residualfuel qualities have shown that the bestcleaning effect, particularly in regard toremoval of catalytic fines, is achievedwhen the centrifuges are operated inseries, i.e. in purifier/clarifier mode.

This recommendation is valid for oldtype centrifuges. For the automaticallyoperating centrifuges delivered in themid�80s, suitable for treating fuels withdensities higher than 991 kg/m3 at 15°C,it is recommended that the maker’s spe�cific instructions be followed.

In this context, see section on highdensity fuels.

If the installed centrifuge capacity is onthe low side, in relation to the specificviscosity of the fuel oil used, and ifmore than one centrifuge is available,parallel operation should be consideredas a means of obtaining an even lowerflow rate. However, in view of theabove results and recommendations,serious consideration should be givento installing new equipment in compli�ance with today’s fuel qualities andflow recommendations.

For determination of the centrifugingcapacity, we generally advise that therecommendations of the centrifugemaker be followed, but the curves inFig. 2 can be used as a guide.

High Density Fuels

In view of the fact that some fuel oilstandards incorporate fuel grades with�out a density limit, and also the factthat the traditional limit of 991 kg/m3 at15°C is occasionally exceeded on ac�tual deliveries, some improvements inthe centrifuging treatment have beenintroduced to enable treatment of fuelswith higher density.

Since the density limit used so far is, asinformed by centrifuge makers, givenmainly to ensure interface control of thepurifier, new improved clarifiers, withautomatic de�sludging, have been in�troduced, which means that the purifiercan be dispensed with.

With such equipment, adequate sepa�ration of water and fuel can be carriedout in the centrifuge, for fuels up to adensity of 1010 kg/m3 at 15°C.

Therefore, this has been selected asthe density limit for new high densityfuel grades.

Thus we have no objections to the useof such high density fuels in our engines,

provided that these types of centrifugesare installed. They should be operatedin parallel or in series according to thecentrifuge maker’s instructions.

Fuel Sampling

SamplingTo be able to check whether the speci�fication indicated and/or the stipulateddelivery conditions have been compliedwith, we recommend that a minimumof one sample of each bunker fuel lotbe retained. In order to ensure that thesample is representative for the oil bunk�ered, a sample should be drawn fromthe transfer pipe at the start, in themiddle, and at the end of the bunkeringperiod.

Analysis of samplesThe samples received from the bunker�ing company are frequently not identicalwith the heavy fuel oil actually bunk�ered. It is also appropriate to verify theheavy fuel oil properties stated in thebunker documents, such as density,viscosity, and pour point. If these valuesdeviate from those of the heavy fuel oilbunkered, there is a risk that the heavyfuel oil separator and the preheatingtemperature are not set correctly forthe given injection viscosity.

Sampling equipmentSeveral suppliers of sampling and fueltest equipment are available on themarket, but for more detailed andaccurate analyses, a fuel analysinginstitute should be contacted.

8

Supplementary Fuel OilTreatment

In a traditional system, the presence oflarge amounts of water and sludge willhamper the functioning of a clarifier, forwhich reason a purifier has been usedas the first step in the cleaning process.With the new automatic de�sludgingclarifiers, the purifier can, as mentioned,be dispensed with. We consider the re�moval of solids to be the main purposeof fuel treatment.

Although not necessarily harmful in itsown right, the presence of an uncon�trolled amount of water and sludge inthe fuel makes it difficult to remove thesolid particles by centrifuging. Therefore,additional equipment has been devel�oped:

HomogenisersHomogenisers are used to disperseany sludge and water remaining in thefuel after centrifuging. A homogeniserplaced after the centrifuge will renderfresh water (not removed by centrifug�ing) harmless to the engine, and even�tually lead to the acceptance of fuelswith no density limit.

Homogenising may also be a means tocope with the more and more frequentlyoccurring incompatibility problems, whichare not really safeguarded against in anyfuel specification. Both ultrasonic andmechanical homogenisers are available.

Homogenisers installed before the fuelcentrifuge can, when considering thefull range of the ISO 8217 fuel specifi�cation, reduce the efficiency of the cen�

trifuge and, thus, the cleanliness of thefuel delivered to the engine.

The sodium will not be removed fromthe fuel in the form of salt water. Thecat fines and other abrasive materialwill be split up into very small particles,which are difficult for the centrifuge toseparate and which will still have a harm�ful wear effect on the engine components.

It is therefore not recommended to in�stall homogenisers before the centri�fuge, see Fig. 3.

Fine filtersFine filters are placed directly after thecentrifuge, or in the supply line to theengine, in order to remove any solidparticles not taken by centrifuging. Themesh is very fine, i.e. down to 5 µm.

9

Fig. 3: Pressurised fuel oil system, with homogeniser

Homogenising before a fine filter canreduce the risk of fine filter blocking bythe agglomeration of asphaltenes.

Super decantersThis, in principle, is a ‘horizontalclarifier’. The aim is to remove sludgebefore normal centrifuging, and thusprevent blocking of the centrifuge.

Fuel Oil System

A pressurised fuel oil system, as shownin Fig. 1, is necessary when operatingon high viscosity fuels. When using highviscosity fuels requiring high preheatingtemperatures, the oil from the enginefuel oil system to the return line will alsohave a relatively high temperature.

The fuel oil pressure measured on theengine (at fuel pump level) should beabout 8 bar, which is equivalent to acirculating pump delivery pressure ofup to 10 bar.

This maintains a pressure marginagainst gasification and cavitation inthe fuel system, even at 150°C pre�heat.

In order to ensure correct atomisation, thefuel oil temperature must be adjustedaccording to the specific fuel oil viscos�ity used.

An inadequate temperature can influencethe combustion and could cause increasedwear on cylinder liners and piston rings,as well as deterioration of the exhaustvalve seats. Too low a heating tempera�ture, i.e. too high viscosity, could also re�sult in a too high injection pressure, lead�ing to excessive mechanical stresses inthe fuel oil system.

In most installations, heating is carriedout by means of steam, and the viscosityis kept at the specified level by a viscosityregulator controlling the steam supply.

Depending on the viscosity/tempera�ture relationship of the fuel oil (the vis�cosity index), an outlet temperature ofup to 150°C might be necessary, as in�dicated on the guidance curves shownin Fig. 4, which illustrate the expectedheating temperature as a function of thespecific fuel oil viscosity in cSt/50°C.

The recommended viscosity meter set�ting is 10�15 cSt. However, service ex�perience has shown that the viscosityof the fuel before the fuel pump is not atoo critical parameter, for which reasonwe allow a viscosity of up to 20 cSt af�ter the heater. In order to avoid toorapid fouling of the heater, the temper�ature should not exceed 150°C.

10

7 43

10 52

12 5915 69

20 87

30 125

cSt SecRW

Normal heating limit

Approximate pumping limit

10 15 25 35 45 55 cSt/100 Co

30 60 100 180 380 600 cSt/50 Co

200 400 800 1500 3500 6000 sec. RW/100 Fo

170

160

150

140

130

120

110

100

90

80

70

60

50

40

30

Temperature after heater

Co

Approximate viscosityafter heater

Viscosity of fuel

Fig. 4: Heating chart for heavy fuel oil

Operational Aspects

All low speed engines from and includ�ing the K�GF (from around 1973) areequipped with uncooled, all�symmetri�cal light�weight fuel injection valves.

These allow constant operation onheavy fuel, due to the built�in possibilityof circulating heated heavy fuel throughthe high�pressure fuel pipes, and fuelvalves during engine standstill.

On the auxiliary engines correspondingcirculation of fuel takes place throughthe fuel pumps while the same recom�mendation applies.

In view of the cost difference betweendiesel oil and heavy fuels, and becauseof the latent risk of diesel oils andheavy fuels of marginal quality formingincompatible blends when changingfuel type, it is recommended that bothmain and auxiliary engines are oper�ated on heavy fuels at all times, whenpossible, irrespective of load. This in�cludes start, stop and manoeuvring.

Should a change to diesel oil be neces�sitated by, for instance, the need for amajor repair of the fuel oil system, aprolonged stop, or the use of verylow�sulphur fuels where required byenvironmental legislation, the heavy fuelin the system can be changed with die�sel oil at any time, provided the change�over procedure is followed, even whenthe engine is not running, see also theengine instruction book.

During engine standstill, the heated fueloil circulating through the fuel systemdoes not require the same low viscosityas is recommended for injection.

Thus, in order to save steam, the heat�ing temperature may be lowered bysome 20°C, giving the circulating oil aviscosity of up to 30 cSt.

For GenSets on standby for immediatestart, the viscosity must be kept withinthe limits given for running conditionsso that the start and generation ofpower can be instantaneous.

The temperature should be raised tothe recommended service value, asillustrated in Fig. 4, about 30 minutesbefore starting�up is expected.

As mentioned previously, the heatingtemperature must not exceed 150°C,and during operation it is not necessaryto apply pipe heating by means of heattracing. When running on diesel oil, theheat tracing system must not be usedat all.

However, it should be noted that thepipe heating system on drain pipesshould remain in operation during run�ning on heavy fuel.

Off�Spec. Fuels

Several selected off�spec. fuels (i.e. beyondISO 8217) have, inter alia, been tested onMAN B&W’s two�stroke research engine:

• Natural gas (stationary 12K80MC�GI�Splant operating in Japan)

• Bitumen

• Orimulsion

• Bio fuel (Holeby engines).

In order to reduce the NOx level in theengine exhaust gas, water can beadded to the fuel oil to create an emul�sion. Clean freshwater should be used,and this is homogenised into the fuel oilat a maximum ratio of approx. one partof water to two parts of fuel oil. Thewater emulsion can be stable with HFObut with lighter fuels, such as gas oiland diesel oil, it may be necessary toadd an emulsifier to the fuel oil before

homogenising the fuel and water. Thehomogeniser is located between theHFO service tank and the engine, i.e.after the fuel oil purifiers.

Our facility is available for such testing.In the event that off�spec. fuels areconsidered for use with MAN B&W en�gines, it is recommended that MANB&W Diesel is contacted for further in�formation regarding operational experi�ence and any necessary precautions.

Lubricating Oil Qualities

Circulating oil, low speed dieselsRust and oxidation inhibited alkalineengine oils of the SAE 30 viscosity gradeshould be chosen. The oils should haveadequate dispersancy/detergency tokeep the crankcase and the pistoncooling spaces free from deposits.For engines with an integrated gear�driven Power Take Off (PTO), a mini�mum FZG load level (Four�square gearoil test) of 8 should be observed.

Contamination of system lube oilIncrease of BN (Base Number) and vis�cosity in system lube oil during operation.

The piston rod stuffing box separatesthe combustion and scavenge airspaces from the crankcase. Therefore,lube oil will not be severely contaminatedwith combustion products and usedcylinder lube oil. However, some cylinderlube oil leaks through the stuffing box,down into the system lube oil sump.

This is revealed by increasing BN andviscosity levels of the system lube oil.Normally, the increase will stop aftersome time and remain at a stable levelwhere topping up with new system lubeoil, to make up for normal consumption,will balance the degree of contaminationof the system oil with cylinder lube oil.

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BN level considerationThe increase in BN can influence theability of the oil to reject water by theusual centrifuging. Water together withcalcium compounds from oil additivesmay form calcium hydroxide and calciumcarbonate and build up a deposit of lac�quer on the bearings. Another risk is theincreased sludge formation when wateris present.

Experience shows, however, that manyengines are operating with up to 30 BN(starting from approx. 8 BN) withoutany operational problems, and withoutany changes in the lube oil performancethat give reason for renewing the oil.

An increase in BN to an equilibriumvalue of up to 25 in BN and in viscosityfrom SAE 30 to SAE 40 is considerednormal, and no action is called for. Anincrease beyond that is not really harm�ful and can, in most cases, be counter�acted by new low�BN topping oil.

The circulating oil consumption on theMC/MC�C engines is very low becausethe engines have fewer leaks and be�cause of the much reduced stuffingbox oil drain, compared to previous en�gine types, causing a higher increase inBN and viscosity. Therefore, it may benecessary to add some new oil to thelube oil sump at times to ensure aproper quality and BN level of the lubeoil. This is done by exchanging part ofthe circulation oil in the sump based onan analysis of the oil.

Circulating oil, auxiliary dieselsRust and oxidation inhibited alkalineengine oils of the SAE 30�40 viscositygrade should be chosen. The oils shouldhave adequate dispersancy/detergency tokeep the crankcase and the piston cool�ing spaces free from deposits.

To cater for appropriate neutralising ofsulphuric acid, formed during combus�tion, an initial BN level of about 20�40is recommended, see Table 3.

For a medium load profile and a fuelwith a normal sulphur content, a TBNof 20�30 is required, while for a high�loadprofile and a fuel with a high sulphur con�tent, the TBN should be 30�40.

Cylinder Oil, Low Speed Diesels

For engines operating on heavy resid�ual fuel oil, a cylinder oil with a viscosityof SAE 50 and BN of about 70 is rec�ommended.

In most cases the high BN cylinder lu�bricant will also be satisfactory duringtemporary operation on diesel oil/gas oil.

In general, changing the cylinder oiltype to correspond to the fuel typeused (i.e. bunker fuel or diesel oil/gasoil) is considered relevant only in caseswhere operation on the respective fueltype is to exceed 10 hours.

However, it should be noted that someof the high alkaline cylinder oils are notcompatible with certain particularly lowsulphur fuels having poor combustionproperties, and with some diesel oils.

If any such incompatibility, indicated bypoor cylinder conditions, is revealedwhen inspecting through the scavengeair ports, it may be advisable to use a cyl�inder oil with lower BN.

Some cases have shown problemswhen using BN70 cylinder oils in con�nection with frequent bunkering of lowsulphur fuels, with a sulphur content of0.8% to 1.5%.

Low alkaline cylinder lubricants aretherefore available on request from themajor lubricating oil suppliers.

Table 3 shows typical lube oils recom�mended for use on marine applicationstogether with the fuel oils specified inTable 2. In order to control and prevent

sulphur corrosion, it has become theindustry standard for marine engines touse cylinder lubricants with a BN of70�80 in combination with the averagemarine fuels, i.e. 380 cSt.

As mentioned, incompatibility, usingBN70 in connection with frequentbunkering of low sulphur fuels, has ledto some cases of cylinder conditionproblems.

The main problem has been the accu�mulation of un�used cylinder oil additives,resulting in excessive deposits on thepiston topland. This has led to highwear, and to the situation that increasedlubrication does not improve the condi�tion. On the contrary, increased lubrica�tion increases the formation of depos�its, leading to acceleration of the problem.

It has been established that a certaindegree of controlled corrosion enhan�ces lubrication, in that the corrosiongenerates small “pockets” in the cylin�der liner running face from which hy�drodynamic lubrication from the oil inthe pocket is created. The alternative,no corrosion, could lead to bore�polishand, subsequently, hamper the cre�ation of the necessary oil film on theliner surface, resulting, eventually, inaccelerated wear. Controlled corrosion– not avoiding corrosion – is thereforecrucial, and adjusting the BN to the fueloil sulphur content is essential on sta�tionary engines and, in special cases,also on marine engines. See page 14“Fuels and Lubes for StationaryTwo�stroke MAN B&W Engines.”

Consequently, a reduced cylinder oilfeed rate will improve the condition.

Special running conditions because offrequent bunkering of low sulphur fuelsand environmental fuel regulations (bythe authorities or self�imposed), requir�ing the use of low sulphur fuel and spe�cial running conditions, might call for alowering of the total alkaline additive

12

content. This can be done by loweringthe dosage towards our minimum feedrate or, alternatively, by using one ofthe specially designed cylinder oils witha lower BN and with full detergency.

Service tests with such specially de�signed low�BN oils have shown goodresults. However, it may be difficult todetermine whether changing to a BN40or BN50 cylinder oil can solve a specificproblem. A lower BN than 40�50 seemsto give an unacceptable performancewith regard to cleanliness in the com�bustion chamber.

For this reason, we recommend that youcontact MAN B&W Diesel A/S, or theengine builder, before making such achange.

GeneralIt should be considered that, irrespectiveof the sulphur content being high orlow, the fuels used in low speed engines

are usually low quality heavy fuels.Therefore, the cylinder oils must havefull capacity in respect of detergencyand dispersancy, irrespective of the BNspecified. This is a technology whichhas to be mastered by the lube oil sup�pliers, who can individually tailor a cyl�inder lube oil to the relevant fuel.

Breaking�in cylinder lube oils fortestbed runningIn addition to determining the optimumoil design for normal operation of thetwo�stroke MAN B&W engines, we alsoinvestigate and test various lube oil de�signs in cooperation with the oil com�panies to find the optimum cylinderlube oils for testbed running.

Most builders of MAN B&W two�strokeengines are using low sulphur DO fuels,primarily for environmental reasons. This,in combination with a relatively highrunning�in lube oil dosage, requires ahigh detergency level in the oil. There�

fore, we generally recommend the useof a BN70 cylinder oil, irrespective ofthe sulphur content of the fuel oil.

When introducing alu�coating on pistonrings and semi�honed cylinder liners,we also introduced a shorter running�inperiod which, furthermore, limits theperiod in which excess cylinder lube oilis supplied, and improves the running�in conditions. This means that the en�tire running�in period, up to 100 hours,is fully acceptable for using BN70 cylin�der lube oils.

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Lubricating oils

Low speed main engines Auxiliary engines Auxiliary enginesL23/30 & L28/32 L16/24, L21/31 & L27/38

Type Circulating oil Cylinder oil Circulating oil Circulating oil

Requirement SAE30/BN 5�10 SAE50/BN 70�80 SAE50/BN 40�50 SAE30/BN 20�25 SAE40/BN 20�40 **

Oil company

BP Energol OE�HT 30 CLO 50�M CL/CL�DX 405 Energol IC�HFX 203 Energol IC�HFX 204�404

Castrol Marine CDX 30 S/DZ 70 cyl. CL/CL�DX 405 Castrol TLX 203 Castrol TLY 204/304/404

Chevron Veritas 800 Marine Delo Cyloil Special Taro Special HT 50 Delo 2000 Marine 30 Delo 3400 Marine 40

Elf Atlanta Marine D3005 Talusia HR70 Talusia LS 40 * Aurella 3020 Aurella 4020 � 4030

Exxon Exxmar XA Exxmar X70 Mobilgard L540 Exxmar 24 TP30 Exxmar 30 TP40

Mobil Mobilgard 300 Mobilgard 570 Mobilgard L540 Mobilgard (TB 25) Mobilgard M430�M440

Shell Melina 30/30S Alexia 50 Alexia LS Argina oil S30 Argina oil S40

Texaco Doro AR30 Taro Special HT70 Taro Special HT 50 Taro 20 DP 30 Taro 20 DP 40, 30 DP 40

* Still under test at the time of publication of this paper,** Depending on load profile and sulphur content

Table 3: International brands of lubricating oils which have been applied with satisfactory results on MAN B&W engines

Performance Verification ofCylinder Oils

All oils listed have gone through a per�formance test for about 4,000 runninghours on a relevant engine type in ser�vice and have, during the test, been in�spected by engineers from MAN B&WDiesel, in cooperation with the oil supplier.

When satisfactory results have beenachieved, MAN B&W Diesel issues a‘Letter of No Objection’ for the use ofthe oil on MAN B&W two�stroke en�gines. However, MAN B&W Dieseldoes not assume responsibility for anydamage caused due to the quality ofan oil mentioned in a ‘Letter of No Ob�jection’. The performance of the oil isthe responsibility of the oil supplier. It isup to the operator to obtain guaranteesfrom the oil supplier that the oil is suit�able for operation on the plant in ques�tion in conjunction with the currentlyused fuel.

If an oil on the list fails to provide ac�ceptable performance, then MAN B&WDiesel will work together with the oil com�pany to clarify the reasons and, ifneeded, have a better oil introduced.If this fails, the ‘Letter of No Objection’will be withdrawn.

The list should not be considered com�plete, and oils from other companiesmay be equally suitable.

Further information about the oil test and‘Letter of No Objection’ can be obtainedby contacting MAN B&W Diesel inCopenhagen.

Fuels and Lubes for StationaryTwo�stroke MAN B&W Engines

Stationary engines operate at load pat�terns and ambient conditions which dif�fer widely from those of their marinecounterparts. This is illustrated in Fig. 5and Table 4 showing the typical operat�ing conditions for both applications.

Thus, Fig. 5 shows that for stationaryengines, the average load is 95�100%during 8000 hours, or more, per year inoperation, whereas for marine enginesthe average load is around 80% and,furthermore, often only for 6000 hoursper year in operation. This means thatstationary engines typically have a morethan 60% higher load factor than marineengines.

Stationary engines are exposed to widelyvarying ambient conditions, see Table 4,i.e. higher air and cooling water temper�atures. Furthermore, stationary engines

are frequently exposed to fuel oils ofnon�marine qualities. The fuel is oftendelivered from one permanent supplier,meaning that the quality from this supplier,good or bad, will prevail. Therefore, lubeoils, especially cylinder oil, have to be indi�vidually selected and, at times, even indi�vidually specified and optimised in order tomatch the fuel oil available.

Table 3 shows typical lube oils to be usedfor marine applications together with thefuel oils specified according to ISO 8217. Inorder to control/prevent sulphur corrosion, ithas become the industry standard for ma�rine engines to use cylinder lubricants with aBN of 70�80 for use with the average marinefuels.

This simple rule does not apply tostationary engines, where the sulphur levelin the fuel usually remains constant, i.e. atthe level set by the supplies available, or,when regulated by local legislation, oftenshows a decreasing tendency over thelifetime of the plant.

Hence, the constant use of a higher�than�average sulphur content, possiblyeven higher than that found in the marinespecification, will call for the use of a higherBN, and for this situation lube oils with BN upto 100 are available.

Correspondingly, long�term use of lower�than�average sulphur fuels will call for theuse of lower BN lube oils, as described forlow sulphur marine fuels.

In addition, the engine load for stationaryengines is usually very high, and the ambi�ent temperature is often higher as well, ref.Fig. 5 and Table 4. Hence, temperaturesare high in the combustion chamber, andthe need to counteract cold corrosion withalkaline additives is lower, thus reducingthe BN requirement.

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60

70

80

90

100

110

0 2,000 4,000 6,000 8,000hours

Time in service over one year

% load

Marine

Stationary

Fig. 5: Typical load profile during a year inoperation

Ambient conditions Stationary enginesMarine engines

Tropical Design

Cooling water temp.

Air inlet temp.

Maximumyearly site

climatic cond.

Average yearlysite climatic

cond.

Minimumyearly site

climatic cond.

32 °C

45 °C

25 °C

25 °C

Blower inlet pressure Depends on height above sea level 1000mbar

1000mbar

Table 4: Typical ambient conditions