- 08 Ιαν 2015, 19:14
#59972
Με το LS εγινε ενας κακος χαμος παλι...πολλοι τρεξανε να κανουνε modifications για να καινε MGO, και στο τελος βγηκε LS FO με 0.1% Sulphur..Απο circular που ειχα φτιαξει για το fleet με βαση οδηγιες απο B&W:
MAN Diesel & Turbo issued on 2009 the service letter for operation in low viscosity fuels.
This Service Letter was written before the ISO 8217-2010 revision, and we expected that the ISO-limit for the HFRR-scar would be: max. 460 µm. - As in the Service Letter.
Now, we have adapted the ISO-8217-2010 (and 2012): HFRR scar max 520 µm.
The same is applicable for all 2stroke MAN Diesel & Turbo engines.
MAN B&W two-stroke engines can operate on fuels fulfilling the ISO 8217:2010 specification, including distillate fuels, without making modifications to the engine itself.
The first thing that you have to check when switching from heavy fuel to a distillate fuel with a low aromatic hydrocarbon content, is the risk of incompatibility between the two products. The change-over procedure takes quite some time, during which there will be a mix of the two very different fuels for an extended period of time. The asphaltenes of the heavy fuel is likely to precipitate as heavy sludge, with filter clogging as a possible result.
Change-over of fuel can be somewhat harmful for the fuel equipment, because relatively cold distillate is mixed with hot heavy fuel. The process therefore needs careful monitoring of temperature and viscosity and during change-over two factors are to be kept under observation. The rate of temperature change of the fuel inlet to the fuel pumps must not exceed 2°C/min to protect the fuel equipment from thermal shock.
The other major factor is the viscosity and its influence on the engine, such as engine condition and maintenance, fuel pump wear, engine adjustment, actual fuel temperature in the fuel system, human factors, etc.
The lowest viscosity suitable for two-stroke diesel engines is 2 cSt at engine inlet .
MAN Diesel & Turbo does not recommend to operate the engine on fuel with viscosities lower than 2 cSt.
Τhe lubricity of the fuel is not regarded as a major issue. Tests have not yet showed any failure due to lubricity of the fuel. Research tests also show, that a failure due to lubricity cannot be provoked.
Regarding cylinder lubrication and the selection of the compatible BN acc to % sulphur, see attached service letter 2014-587 and approved list of cylinder oils.
New fuels with less than 0.1%S
There are a range of new fuels launched at the moment. These new types are not of the distillate type, but a new blend or type.
General characteristics are:
• Higher viscosity than distillate.
• Some of these fuels might contain cat-fines (Al+Si).
Hence it is very important to use the fuel cleaning and conditioning system.
• Some of these fuels have high pour points.
Hence make sure that the temperature in the tanks and pipes are heated to a temperature above the pour point of the fuel. If the temperature falls below the pour point, there could be an issue of waxy precipitations.
• Compatibility to other fuels could also be an issue.
Do not mix different kinds of fuels.
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The Cylinder lube oil
o A low BN oil must be chosen when operating on distillate or fuels with less than 0.1%S.
In case of over-additivation with the acid neutralising additive, the risk of deposit formation on the piston as well as bore-polishing increases. Both deposit formation and bore-polishing may lead to scuffing/increased wear.
For this reason, change to a BN40 or lower cylinder oil is recommended when changing to distillate operation, as well as optimising the feed rate towards the minimum feed rate when operating on low/ultralow sulphur fuels continuously.
o Attached please find newest Service Letter on Cylinder Lubrication, SL2014-587. The recommendations for lube oil for distillate have not changed since last edition.
o There is no distinction between engines using 80-100 BN oil and engines using 70 BN oil. All engines should change to low-BN oil (40 BN and lower) when changing to distillate.
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New low BN cylinder oils
The following oil companies have received a no objection letter for ultra-low BN cylinder oils and the List of marine oils will be updated later this year.
Company Lube oil Lube oil main properties
Castrol Cyltech 40SX 40BN, SAE 50
Chevron Taro Special HT LF 25 BN, SAE 50
ExxonMobil Mobilgard 525 25 BN, SAE 50
Shell Alexia S3 25 BN, SAE 50
TOTAL Talusia LS25 25 BN, SAE 50
Lubrizol The customer should contact their supplier 17 BN, SAE 50
At the moment B&W's recommendations are as follows:
1-2 weeks operation on 0.1%S fuel: ≤25-40 BN
Long-time operation on 0.1%S fuel: ≤25 BN
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ExxonMobil Premium HDME 50 with 0.1 %S Marine Fuel
MAN Diesel & Turbo (MDT) have been involved in the testing of ExxonMobil Premium HDME 50 with 0.1 %S. The 2 stroke main engine trial had a duration of approx. 320 h. There has also been genset engine trial (4-stroke)(2000 h). Both trials were completed with satisfactorily results. There were no issues during the main engine trial. There were no reported problems during switchover. MAN B&W especially looked for waxy deposits in the fuel system, but there were none. Overall, MDT, the crew and the ship-owners were satisfied with the performance of the fuel.
It is recommended to use dedicated heated tanks for the fuel and the pipes should also be heated as for ordinary HFO operation. Do not mix different kinds of fuels.
It is of course very important to use a cylinder lube oil which is suitable for low sulphur operation. It is recommended 40 BN or lower. There will be low BN oils available in the market well in time for the 2015 SECA.
Typical properties of fuel: Kinematic viscosity, cSt@50°C: 25-45; Density @15°C kg/m3 : 895-915.
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Το κοστος μεχρι στιγμης του νεου LS FO με 0.1% S, ειναι περιπου 50-100USD λιγοτερα απο το 0.1% MGO (αρκετα ακριβοτερο απο το τωρινο LS FO 1.0% ), και ειναι διαθεσιμο στα μεγαλα bunkering port στις ECA (Falmouth, Rotterdam), gulf of Mexico κτλ..
) αλλά οι μικροί θα έχουν σίγουρα πρόβλημα με τη διαχείρηση του project.
) Προσπαθώ να βγάλω το ψωμί μου και πάλι στο σφαγείο, Δάσκαλε... (αλλά με πολύ ζόρι, δυστυχώς... 
)
