Marine Engine Lubrication After 2020: What To Expect in The Next Decade
Marine Engine Lubrication After 2020: What To Expect in The Next Decade
Marine Engine Lubrication After 2020: What To Expect in The Next Decade
Marine engine
lubrication after 2020
What to expect in the next decade
November 2018
Contents
Introduction.........................................................................................................3
Bibliography........................................................................................................18
The following section discuss the possible impact IMO 2020 regula-
tions will have on the two marine engine lubrication systems.
* Cat fines are the most abrasive of all substances in heavy fuel oil. These are
fragments of a catalyst added to the oil in the refining process. Composed of
solid particles of aluminum and silicon compounds, catalytic fines are almost
as hard as diamond and vary in size from sub-micron to approximately 50 µm.
The lube oil acts as transport medium for insolubles produced in the
engine. The degree of engine fouling is determined by the
concentration of insolubles and the tendency of the oil to leave
deposits. (CIMAC, 2004)
For the reasons above, trunk piston engines burning residual fuels
are best fitted with continuously running centrifuge purifiers/
separators of sufficient capacity, cleaning their lubricating oil by
removing water, soot and other contaminants.
How each of these fuels might impact the lube oil is discussed in the
following sections.
Note: This document focuses on medium-speed trunk engine lubrication systems
versus low-speed crosshead engine lubrication systems, which isolate the
combustion chamber from the fuel oil.
2. VLSFO (0.50% S)
This fuel type will likely dominate the market in 2020 following
enforcement of the IMO legislation – derived from heavy fuel oil
(HFO) refinery streams, bringing the combined sulphur level as close
to the 0.50% S limit as possible.
However, lube oil treatment systems will still need to remove water
and oxidation contaminants, as well as engine wear particles, from
the engine.
5. Biofuel (0.0% S)
Biofuel or biodiesel are fuels derived from vegetable oils (e.g. palm
oil, soybean oil, rapeseed oil), animal fats (e.g. tallow oil) and waste
organic compounds. Most common biofuel types include Fatty Acid
Methyl Esters (FAME), ethanol and Hydrotreated Vegetable Oil (HVO).
Diesel engines require a lube oil with a variety of properties. Not only
must the lube oil neutralize the fuel acidity, it must be capable of
cleaning (and keeping clean) engine components, dissipating engine
heat, and protecting against rust and corrosion. Moreover, it must
perform these actions for extended periods.
Lube oil also helps keep deposits from forming throughout the entire
lubrication system, including circulation lines, check valves and sight
glasses. With fresh and clean lube oil in the system, marine engine
performance and efficiency can be optimized.
Viscosity at 40°C Maximum 140 Maximum 150 mm2/s (cSt) ASTM D 445
Total insoluble material Maximum 0.7 Maximum 1.0 % m/m 1 ASTM D 893b
ASTM D 95 or
Water content Maximum 0.20 Maximum 0.30 % m/m
ASTM D 1744
Strong Acid Number (SAN) 0.0 Maximum 0.0 mg KOH/g ASTM D 664
1 % m/m means by mass, e.g. a water conent of 0.20% m/m means that the
water content is 0.20% of the mass of the total solution.
2 To do the FZG gear oil test is recommended one time each year.
NOTE: Use these limits as a guide. You cannot make an estimate of the system oil
by one parameter. Get also other oil parameters to find the causes of problems.
d2 ( ρP – ρLO)
vc = ω2r
18ƞ
Separation efficiency
QLO = P V n
t
The required number of passes (n) varies by fuel type and engine
manufacturer. MAN recommends n(HFO) = 7, n(MGO/MDO) = 5 and
n(dual fuel engines with LNG/LPG) = 5. (MAN Diesel & Turbo, 2016).
Wärtsilä recommends n(HFO) = 5 and n(MDO) = 4. (Wärtsilä, 2018).
0.9
0.8
0.7
Insoluble (soot) level / %
0.6
0.5
0.4
0.3
0.2
0.1
0
0 2000 4000 6000 8000 10000 12000 14000
Impact of purification on soot load in medium speed engines (Source: Chevron Lubricants).
There are still numerous unanswered questions regarding the impact the
2020 IMO regulations will have on marine engine lubrication systems.
100000909-1-EN 1811