Marine Diesel Oil (MDO) is a type of
fuel oil
Fuel oil is any of various fractions obtained from the distillation of petroleum (crude oil). Such oils include distillates (the lighter fractions) and residues (the heavier fractions). Fuel oils include heavy fuel oil, marine fuel oil (MFO), bun ...
and is a blend of
gasoil
Fuel oil is any of various fractions obtained from the distillation of petroleum (crude oil). Such oils include distillates (the lighter fractions) and residues (the heavier fractions). Fuel oils include heavy fuel oil, marine fuel oil (MFO), bun ...
and
heavy fuel oil
Heavy Fuel Oil (HFO) is a category of fuel oils of a tar-like consistency. Also known as bunker fuel, or residual fuel oil, HFO is the result or remnant from the distillation and cracking process of petroleum. For this reason, HFO is contaminate ...
, with more gasoil than intermediate fuel oil used in the
maritime
Maritime may refer to:
Geography
* Maritime Alps, a mountain range in the southwestern part of the Alps
* Maritime Region, a region in Togo
* Maritime Southeast Asia
* The Maritimes, the Canadian provinces of Nova Scotia, New Brunswick, and Princ ...
field. Marine Diesel Oil is also called "Distillate Marine Diesel".
MDO is widely used by medium speed and medium/high speed marine diesel engines. It is also used in the larger low speed and medium speed propulsion engine which normally burn
residual fuel.
Those fuels result from a catalytic
cracking and
visbreaking A visbreaker is a processing unit in an oil refinery whose purpose is to reduce the quantity of residual oil produced in the distillation of crude oil and to increase the yield of more valuable middle distillates (heating oil and diesel) by the re ...
refinery.
Marine diesel oil has been condemned 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, MDO is favored particularly by
shipping industry
Maritime transport (or ocean transport) and hydraulic effluvial transport, or more generally waterborne transport, is the transport of people (passengers) or goods (cargo) via waterways. Freight transport by sea has been widely used throug ...
.
Specification
ISO 8217 of the
International Standards Organization
The International Organization for Standardization (ISO ) is an international standard development organization composed of representatives from the national standards organizations of member countries. Membership requirements are given in Art ...
(ISO) is the primary standard of MDO.
Marine fuels range in
viscosity
The viscosity of a fluid is a measure of its resistance to deformation at a given rate. For liquids, it corresponds to the informal concept of "thickness": for example, syrup has a higher viscosity than water.
Viscosity quantifies the inte ...
from less than one centistoke (cSt) to about 700 cSt at 50°C (122°F).
(1 cSt = 1 mm2/s.) And higher viscosity grades are preheated during use to bring their viscosity into the range suitable for
fuel injection
Fuel injection is the introduction of fuel in an internal combustion engine, most commonly automotive engines, by the means of an injector. This article focuses on fuel injection in reciprocating piston and Wankel rotary engines.
All comp ...
(8 to 27 cSt).
But MDO does not need to be preheated before using. According to Chevron, MDO has a sulfur limit varies from 1 to 4.5 percent by mass for different grades and Sulfur Emission Control Areas (SECAs).
Manufacturing procedure
MDO is made from a catalytic
cracking and
visbreaking A visbreaker is a processing unit in an oil refinery whose purpose is to reduce the quantity of residual oil produced in the distillation of crude oil and to increase the yield of more valuable middle distillates (heating oil and diesel) by the re ...
refinery.
The catalytic cracking operation breaks large molecules into small molecules. It happens in high temperature and with appropriate
catalyst
Catalysis () is the process of increasing the rate of a chemical reaction by adding a substance known as a catalyst (). Catalysts are not consumed in the reaction and remain unchanged after it. If the reaction is rapid and the catalyst recyc ...
.
Visbreaking A visbreaker is a processing unit in an oil refinery whose purpose is to reduce the quantity of residual oil produced in the distillation of crude oil and to increase the yield of more valuable middle distillates (heating oil and diesel) by the re ...
is a process that turn the bottom product of the vacuum unit, which has extremely high
viscosity
The viscosity of a fluid is a measure of its resistance to deformation at a given rate. For liquids, it corresponds to the informal concept of "thickness": for example, syrup has a higher viscosity than water.
Viscosity quantifies the inte ...
, into lower
viscosity
The viscosity of a fluid is a measure of its resistance to deformation at a given rate. For liquids, it corresponds to the informal concept of "thickness": for example, syrup has a higher viscosity than water.
Viscosity quantifies the inte ...
, marketable product.
In visbreaking, a relatively mild thermal cracking operation is performed.
And the amount of cracking is limited by the overruling requirement to safeguard the heavy fuel stability.
Use
The market of MDO is much smaller than on-highway diesel. According to the a 2004 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.
On the other hand, On-highway diesel takes up 59.5% of diesel fuel sales.
This small sales share of MDO is due to the high proportion of petroleum resid that made it can be used on large marine engines.
According to Chevron, 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.
Regulations and restrictions
The
International Maritime Organization
The International Maritime Organization (IMO, French: ''Organisation maritime internationale'') is a specialised agency of the United Nations responsible for regulating shipping. The IMO was established following agreement at a UN conference ...
(IMO) develops regulations for marine shipping. Among those regulations,
MARPOL
The International Convention for the Prevention of Pollution from Ships, 1973 as modified by the Protocol of 1978, or "MARPOL 73/78" is one of the most important international marine environmental conventions. MARPOL 73/78, MARPOL is an amalg ...
(the International Convention for the Prevention of Pollution from Ships) is the most widely adopted one.
MARPOL is the main international convention covering the prevention of operational or accidental pollution of the marine environment by ships.
Inside
IMO, there is a committee called
MEPC
The Middle East Policy Council (MEPC) is a Washington, D.C.-based 501(c)3 non-profit organization that produces analysis and commentary on issues impacting U.S. national interests in the Middle East. It was founded in 1981 under the stated mission ...
(Marine Environment Protection Committee). MEPC has meetings periodically and discuss resolutions to current
marine pollution
Marine pollution occurs when substances used or spread by humans, such as industrial waste, industrial, agricultural pollution, agricultural and municipal solid waste, residential waste, particle (ecology), particles, noise, excess carbon dioxid ...
by adding amendments to its official documents.
References
Liquid fuels
Diesel fuel
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