The initial IMO Greenhouse Gas Strategy has outlined goals to reduce the carbon intensity of international shipping by at least 40% by 2030 and pursuing efforts towards reduction of 70% by 2050. Carbon intensity is measured as the amount of CO2 emission (gram) from a ship which sails & transports 1 (ton) of cargo for 1 (nautical mile).
In addition, the total annual GHG emissions from international shipping has also set to be reduced by at least 50% by 2050 compared to 2008 as base year. Total is referred to the absolute amount of GHG emissions from the international shipping.
To achieve the targets, IMO has set short-term, mid-term and long-term goals.
Short-term goal is tighter EEDI and SEEMP. Some of the mid-term goals are introducing new indicators for energy-efficiency measures of new and existing ships; plan for low carbon fuels such as biofuels, LNG, and others. Long-term goal is development of zero-carbon fuels.
Biodiesel blends is one of the options to achieve the mid-term goals set out in the initial IMO GHG strategy.
The advantages of biodiesel blends as alternative marine fuels are:
However, usage of biodiesel blends on board ship do have some disadvantages:
The main constituent of Biodiesel is fatty acid methyl ester (FAME), non-hydrocarbon containing carbonyl group. Use of marine fuels containing FAME onboard ship may potentially pose some operation issues as highlighted in the following sections.
Indicative calculations by ISO 8217 for the Specific Energy of bio diesel blends may not be accurate owing to the change in the chemical composition of the fuel, particularly for higher FAME content. It is recommended to conduct Bomb Calorimetry and determination of Hydrogen content of the fuel to identify the gross/lower calorific value of the fuel to determine the engine’s performance accurately.
In additional to the ISO8217 test parameters, the following are recommended for Biodiesel Blends (B20 to B50).
|Test Parameters||Test Method||Bio-Derived||Significance of Analysis|
|Fatty Acid Methyl Esters (FAME)||EN 14078||√||To measure the FAME content of biodiesel blends|
|Cloud Point||ISO 3015||√||To evaluate potential low temperature operation issue|
|Cold Filter Plugging Point (CFPP)||IP 309||√|
|WAT/WDT (For Residue derived Biodiesel only)||ASTM D8420 or ASTM D5773 Equivalent||√|
|Oxidation Stability||ISO 12205||√||To evaluate Stability & Long-Range Storage|
|Total Bacteria Count & Total Yeast & Mould||IP 385||√||√|
|Fuel Stability Reserve||P-value by SMS 1600||√|
|Total Sediment Accelerated||ISO 10307 1||√|
|Total Sediment Existent||ISO 10307‑1||√|
|Copper Corrosion||ASTM D130||√||√||To evaluate Corrosive effect|
|Determination of Fatty Acids, Monoglycerides and Glycerol||GCMS - SPE||√||√|
|Gross Calorific Value||ASTM D240||√||√||To measure energy content of biodiesel blends|
|Net Calorific Value||ASTM D240||√||√||To measure energy content of biodiesel blends|
|Rust Prevention Characteristics||ASTM D665a||√||√||To evaluate corrosiveness property of biodiesel blends|
|Fuel Combustion Analysis||IP541||√||√||To evaluate ignition and combustion properties of biodiesel blends|
|Carbon Content, Hydrogen Content, Nitrogen Content and Oxygen Content||ASTM D5291||√||√||To determine carbon content, hydrogen content, nitrogen content and oxygen content of biodiesel blends|
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