Description
Marine Diesel Oil (MDO) is a type of fuel oil and is a blend of
gasoil and heavy fuel oil. This is with less gas oil than
intermediate fuel oil use in the maritime field. The Diesel Oil is
also known as Distillate Marine Diesel. MDO is widely use medium
speed and medium / high speed marine diesel engines. It is also use
in the larger slow speed and medium speed propulsion engine which
normally burn residual fuel. Those fuels resulting from a catalytic
cracking/visbreaking refinery.
Marine diesel oil is condemn for its nimiety of sulfur, so many
countries and organizations established regulations and laws on MDO
use. Due to its lower price compared to more refined fuel, Shipping
industry favors MDO particularly.
Specification
ISO ***7 of the International Standards Organization (ISO) is the
primary standard of MDO. [2] Marine fuels range in viscosity from
less than one centistoke (see viscosity) (cSt) to about **0 cSt at
*0°C (**2°F).[2] (1 cSt = 1 mm2/s). And higher viscosity grades
preheat during use to bring their viscosity into the range suitable
for fuel injection (8 to *7 cSt). [2]
But MDO does not need to preheat before using. According to our
technical results Our, MDO has a sulfur limit varies from 1 to 4.5
percent from mass for different grades and Sulfur Emission Control
Areas (SECAs). [2]
Manufacturing Procedure
MDO is made from a catalytic cracking/visbreaking refinery. [3] The
catalytic cracking operation breaks large molecules into small
molecules. It happens in high temperature and with appropriate
catalyst. [3] Visbreaking is a process that turn the bottom product
of the vacuum unit, which has extremely high viscosity, into lower
viscosity, marketable product.[3]
In visbreaking, a relatively mild thermal cracking operation
performs. And the overruling requirement to safeguard the heavy
fuel stability and limit the amount of cracking. [3]
Use
The market of MDO is much smaller than on-highway diesel. According
to the a ***4 U.S. Diesel Fuel Sales statistics from U.S.
Department of Energy, Energy Information Administration, Marine
shipping only takes 3.7% of total diesel market. Besides,
On-highway diesel takes up *9.5% of diesel fuel sales. [2] This
small sales share of MDO is due to the high proportion of petroleum
resid that made it can use on large marine enginee.
Furthermore, petroleum resid, or inorganic salts, in the fuel
result in injector tip deposits that prevent the injector from
creating the desired fuel spray pattern. But those low-speed, large
marine diesel engines are appropriate for using fuel containing
large amounts of petroleum resid. [2]
Regulations and Restrictions
The International Maritime Organization (IMO) develops regulations
for marine shipping. Among those regulations, MARPOL (the
International Convention for the Prevention of Pollution from
Ships) is the most widely preferable option.
However, MARPOL is the main international convention covering the
prevention of operational or accidental pollution of the marine
environment.
Inside IMO, there is a committee known as MEPC(Marine Environment
Protection Committee). MEPC has meetings periodically and discuss
resolutions to current marine pollution through adding amendments
to its official documents. [4]
