BIOFUELS Biofuels can reduce GHG emissions significantly but they have many drawbacks and potential dangers from their consumption. Biofuels are expected to have lower calorific value, hence an increase in actual consumption for same power. The net final benefits in emissions needs to be calculated carefully. SOLAS does not define fuel oil or (biofuels) for combustion purposes, nor mandates use of petroleum derived fuel oil or compliance with ISO8217 standards.
ISO 8217:2017: Covers biofuels up to 7% mixing. For all other biofuels there is no existing standard in the marine industry. EN14214:2012 ( FAME) : Not applicable to marine fuels. EN15940:2016 (Parafinic diesel from synthesis or hydrotreatment ) : Not applicable to marine fuels Marpol Annex VI, Reg 18.3.2.1, 18.3.2.2 : A fuel oil which is a blend of not more than 30% by volume of biofuel shall follow regulation 18.3.2.1, while a blend of more than 30% shall follow 18.3.2.2. Calorific value ( specific energy ) must be measured. Formulae in ISO 8217 are not valid for biofuels. There is no analysis tool, in ISO 8127, for measuring how much biofuel a fuel contains.
When biofuels are used without making any changes in Main Engine or DG Engines Nox Settings, or Nox Components, no additional approval is required from Class or Vessels Flag. Bunkered biofuels or biofuel blends would be required to be delivered with MSDS that meet IMO criteria. In case the use of a biofuel requires some change in nox settings of an engine, then approval from authorities is required, and sea trials in the presence of a class surveyor to confirm new values.
MAN B&W
On average, the NOx-levels for FAME-type B100 were in the same range as that for the tested RM (residual) grade fuels Hydrotreated Vegetable Oil HVO fuel quality is similar to DM (distillate) fuel quality; operation on HVO is therefore expected to result in similar NOx emissions as for DM fuel grades.
Mitsui
Wartsilla
Yanmar
FAME (Fatty acid methyl aster): FAME is produced from vegetable oils, animal fats or waste cooking oils by transesterification, where various oils (triglycerides) are converted to methyl esters. This is the most widely available type of biodiesel in the industry and is often blended with regular marine diesel. The marine fuel specification standard ISO 8217:2017 includes additional specifications (DF grades) for distillate marine fuels containing up to 7.0 volume %FAME. The FAME used for blending shall meet specification requirements of EN 14214 or ASTM D6751. FAME-Diesel blends with up to 30% BTL content are also used in automotive applications and referred to as B20 or B30. International standards: EN 14214, ASTM D6751, EN 590 BTL (Biomass to liquid fuels): BTL is a synthetic fuel produced from biomass by means of thermo-chemical conversion. The end product can be fuels that are chemically different from conventional fuels such as gasoline or diesel, but can also be used in diesel engines. International standards: EN 16709, EN 15940 HVO (Hydrotreated vegetable oil): HVO or HDRD (hydrogenation derived renewable diesel) is the product of fats or vegetable oils – alone or blended with petroleum refined by a hydrotreating process known as fatty acids to hydrocarbon hydrotreatment. Diesel produced using this process is often called renewable diesel to differentiate it from FAME biodiesel. The overall production process is typically more costly than for FAME biodiesel, however, HVO/HDRD is drop-in fuel which can be directly introduced in distribution and refueling facilities as well as existing diesel engines without any further modification. International standards: ASTM D 975
Microbial growth: Bacteria and mold may grow if condensed water accumulates in biodiesel fuel. Microbial growth leads to excessive formation of sludge, clogged filters and piping. Frequent draining of tanks and application of biocide in the fuel may reduce or mitigate microbial growth. Biodiesel can degrade over time, forming contaminants of polymers and other insoluble. Could form deposits in piping and engine, compromising operational performance. In advanced stages this could lead to increased fuel acidity, which could result in corrosion in the fuel system and accumulation of deposits in pumps and injectors. It is therefore recommended not to bunker the fuel for long time storage before use, but to treat the fuel as fresh goods and to use within relatively short period of time. Adding antioxidants to the fuel at an early stage may improve the ability for somewhat longer time of storage without degradation. Low temperature: Biodiesels in higher concentration usually has higher cloud point than diesel (depending on feedstock), leading to poor flow properties and clogging of filters at lower temperatures. It is therefore important to know the product’s cold flow properties and to keep the storage and transfer temperatures above the cloud point. Corrosion: Most critical for biodiesel in higher concentration (B80-B100). Could degrade some types of hoses and gaskets leading to loss of integrity and interact with some metallic material such as copper, brass, lead, tin, zinc, etc. Could also result in increased formation of deposits. Hence, it is important to verify that these components in the fuel system are endurable and can be used together with biofuel. Possible degeneration of rubber sealings, gaskets and hoses: It is important to verify that these components in the fuel system are endurable and can be used together with biofuel. Conversion: Biodiesel has shown to have a solvent property, when switching from diesel to biofuel it is expected that deposits in the fuel system will be flushed, clogging fuel filters. It is recommended to flush the system and/or to monitor filters during this period. Note : Operation on biofuel may increase NOx emissions. SEEMP: The reporting of the annual fuel consumption data is according to the methodology included in the approved SEEMP part II, that is required to be carried onboard each ship by Annex VI regulation 26. The use of biofuels may therefore require a change to the SEEMP part II and any required amendments should be considered in the implementation plan as identified under Ch 2,1 Safety 1.2.2 and detailed further under Ch4,2 Implementation plan. This has to be investigated further as to what may be affected. In case of any legal dispute there will be difficulties arising in defending a case where there are no fuel standards and therefore no way to see if the bunkered fuel was according to some spec or not.
Recommended VPS APS Testing scope proposal. Stage 1 : take sample from the biofuel FAME 100% base which will be used for mixing. This means approaching the barge days before bunkering. Stage 2 : take sample from the biofuel after mix using stage 1 fuel. Then make a combined analysis. It would be highly recommended to carry out wax temperature and de-wax temperature tests. Fuels when they fall below their wax temperature, may experience wax formation and difficulty of passing filters. In this case operators have to heat them past their de-wax temperature to remove the wax, but they take a higher risk of sludge formation which cannot be removed. With higher temperatures the TSP is also increasing, and with a standard limit of 0.1% you really do not want to go realistically over 0.03%-0.04%. Within 3 months TSP also increases gradually. (Note : Special attention is to be taken when going drydock to what is the wax temperature of the fuel, as sometimes even atmospheric temperature falls way below wax formation temperature of some fuels so you may enter drydock using a fuel without any issues to consume and exiting drydock full of wax and with some issues to deal)
There are a number of problems which owners have to face for trouble free consumption of biofuels. Summary of issues to remember
