Biofuels present problems for marine transport, handling and storage

News Release Thomas Miller P&I Ltd August 6, 2010

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The production and use of biofuels for transport has
increased dramatically in recent years and is set to continue, reducing carbon
dioxide emissions and meeting growing consumer demand. As most biofuels will be
transported by sea, the industry needs to take stock of its growing experience
of what can go wrong aboard ship and develop safe and efficient shipping,
loading, handling and storage practices.
 
Demand for biodiesel is expected to grow at an estimated
annual compound rate of 15 per cent, rising from 20 million metric tonnes in
2010 to 45 million tonnes in 2015. Global biodiesel and ethanol sales could
reach US$ 247 billion by 2020, up from US$ 76 billion predicted for 2010. In the
first half of 2008/2009, about 670 million litres of biofuels were supplied to
the UK
transport market, with 92 per cent (about 616 million litres)
imported.
 
The UK Government is stepping up its targets for forecourt
sales of fuels from renewable sources to five per cent by 2013/14. The EU
Renewable Energy directive would like it to be more as new sustainable biofuels
come to market. By 2030, Lloyd’s Register predicts global demand for 100 million
tonnes of biofuel, requiring an extra 400 handysize tankers to transport
it.
 
The situation is reviewed
in Biofuels: marine transport, handling and storage issues, prepared by
The Carefully To Carry Committee and published by the UK P&I
Club.
 
Blends
of biofuels and conventional fuels are essentially mixtures of mineral oil based
hydrocarbons and noxious liquid substances. The two
main classes of ‘first generation’ biofuels in widespread use are biodiesel and
bioethanol. 
 
Biodiesel is derived from vegetable oils, such as palm,
coconut, rapeseed, soybean and tallow, and from animal fats. Better known as
Fatty Acid Methyl Esters (FAMEs), these are produced by reacting vegetable oil
or animal fat with an alcohol, usually methanol. The transesterification process
brings the properties of the raw materials closer to those of conventional
petroleum diesel. FAME can be used neat as a fuel but is more commonly blended
with petroleum diesel for use in diesel engines.
 
The different chemical compositions of FAME raw materials and
their blend levels mean the end products vary in terms of stability,
degradability and cold temperature performance. This will affect storage,
handling, treatment, engine operations and emissions.
 
Bioethanol refers to ethanol produced by fermenting
renewable sources of sugar or starch crops, such as sugar cane, sugar beet,
sorghum, corn, wheat and cassava. 
 
Unlike FAME,  bioethanol is a single chemical compound, which is
volatile, colourless  miscible with 
water and hygroscopic. Again, bioethanol can be used neat
but is generally blended with conventional gasoline. 
 
P&I club executives are beginning to receive insurance
claims stemming from biofuel problems, most of which emanate from
FAMEs. There is no standardised analytical technique for detecting
FAME materials in fuel oils and data on their effect on marine fuel systems is limited.

 
Water contamination is the main problem as FAMEs absorb
water via sea water ingress, tank washing residues, atmospheric
humidity in tanks’ ullage spaces and other sources. 

 
FAME can hold high levels of water in
suspension, rendering cargo off-specification. Water can promote hydrolytic
reactions, breaking down the FAME to form free fatty
acids. Such species are corrosive and may attack exposed metal surfaces. Water
can separate out from FAMEs, promoting unwanted microbiological growth, which
may lead to filter blocking and corrosion.
 
Potential shipping problems include degradation reactions
by trace metals, such as copper heating coils or zinc-containing tank coatings.
Thermal stability will be affected if FAME cargoes are
stored next to heated tanks. Dry nitrogen blankets can help to prevent
degradation reactions through air contact.
                                                                                        
FAME can adsorb onto the walls of tanks or
pipelines and de-adsorb into subsequently carried products, causing problems for
multi-product pipelines or storage tanks, necessitating great care with tank
cleaning and flushing and draining common lines. Switching from B5 diesel to jet
fuel requires at least a hot water tank wash. Some would advocate at least three
intermediate FAME free cargoes plus the hot water wash
before loading jet fuel.
 
Tankers
carrying multiple products risk inadvertently contaminating jet fuel cargoes
with traces of FAME. The EN590 specification for
ultra-low sulphur diesel (ULSD) allows up to seven per cent
FAME content by value.  Ship’s tanks
and lines should be completely stripped of all ULSD before loading jet
fuel.
 
FAME acts as a solvent, taking up any organic
residue, dirt or scale that may have accumulated on surfaces of tanks or
pipelines. It attacks and quickens the ageing process of certain materials,
including elastomers.
 
Unwanted water is also a major problem with bioethanol. The
ethanol itself is hygroscopic and highly soluble in water. Small quantities of
water can be dissolved in gasoline/bioethanol blends but, if there is too much,
the ethanol will separate from the gasoline, forming an alcohol-rich
water/ethanol aqueous phase and an alcohol- poor gasoline phase.
                                                           

The former
will collect at the bottom of the ship’s tank or storage tank and is likely to
be highly corrosive and not usable as fuel. The gasoline phase may
be considered a “minor hazard to either marine resources or human
health” if discharged into the sea from tank cleaning or deballasting
operations.  
 
Bioethanol also acts as a solvent, cleaning out dirty
storage tanks and lines but becomes contaminated itself in the
process.
 
UK Club
Loss Prevention Director Karl Lumbers explained:  ”As volumes
increase and new fuel sources, such as jatropha and algal oil enter the market,
we can expect new sources of claims. The production and distribution of
biofuels, particularly on board ship, will continue to provide a very real
challenge. A  knowledge of these products’ properties will be
very beneficial in minimising the risk of unwanted claims.”
 
The Carefully to Carry Committee – the UK P&I Club’s
advisory committee on cargo matters---was established in 1961 to help reduce
claims through expert and timely advice. Carefully to Carry is regarded as a key
source of guidance for shipowners and ships’ officers and have been used in the
settlement of claims and court hearings. All articles are available in print and
on disk via the UK P&I Club website.<A href="UrlBlockedError.aspx"
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