Vessels regularly need to provide bunker or cargo products to their tanks.( typically Marine gasoil MGO or Heavy fuel oil HFO ). There are different products compatible with the specificity of one vessel’s engine and the area where the vessel operate ( local regulation or simply water temperature ).
Fuel stands for a significant part of a project cost. Cost savings will draw a clear impact on project bottom line. Fuel traders spot prices offers are made of a market rate ( driven with indexes ) and a logistics premium.
Among other things, quality and quantity are the 2 main aspects to be controlled.
Typical documents are : COQ ( certificate of quality ) and BDN ( bunker delivery note ).
In some geographical areas, only typical specifications are provided. Some clients may be very strict about the quality of their bunkers and it may be required to set up additional fuel quality control measures beforehand.
Contractual frame agreements have to be set up with preferred suppliers ( fuel traders, broker, physical suppliers ) protecting your rights on the cargo “lien” and optimizing your payment terms. Spot deals are concluded on a regular basis based on competitive bidding or, from time to time if cost control is a priority, price can be fixed for the duration of a project.
Operations are controlled by barge operators and physical suppliers. A transparent and trusted relationship with suppliers is key to minimize risks of delays and quality issues.
SHOREREP is acting as fuel broker. A broker protect his Client ‘s interests and monitor remotely actual bunkering operations while a trader ( although skilled and acting professionally ) is running a business and can speculate on product value.
PP, CFPP, CP
Pour point is the lowest temperature at which the fuel will flow and can be pumped out.
Pour point should be low ( tolerance of 10°C)
CFPP( cold filter plugging point ) is the lowest temperature at which the fuel will pass through a 40µ filter. ( filters at engine entrance are 10µ )
Cloud point is the temperature at which dissolved particles precipitate and form a cloudy appearance, mainly paraffin crystallization clogging filters. This is a growing concern with ultra low sulphur fuel.
Cloud point should be low , value is strict / no tolerance. If sea water falls under Cloud point temperature, then wax crystals pop up.
Only Pour point is part of ISO 8217 standard.
The future requirement for lower sulphur fuels has engineering implications:
- It Increases the microorganism growth as sulfur is a natural microbe inhibitor.
- It decreases the lubricity of MGO
- Switch over HFO and MGO product are much more complex than switch from HSFO to LSFO.
Also, presence of the organic compound FAME ( Fatty acid Methyl esther is more and more common and may become a standard additive as it is for automotive fuel. FAME can contributes to biological growth and flow properties.
The structure of HFO-IFO is more aromatic than before, with more asphaltenes, more fuel instability, more contaminants.
Minimum value is 60°C on a vessel ( SOLAS ) . a variation of 2-3 °C is expected due to the % repeatability of test protocols ( 5% of nominal value ). If FP < 60°C, Classification society requires clarification on the carriage of this fuel.
Equilibrium between the aromatic hydrocarbons and the asphaltenes are responsible for maintaining the stability of the fuel. Blending HFO with paraffinic distillate fuel or blending of 2 HFO with widely different aromatic content ( density and viscosity ) may reduce the aromaticity of the fuel matrix and can result in agglomeration and precipitation of asphaltenes in the form of sludge. This is called incompatibility. A compatibility test done by a laboratory will determine if products are compatible. in case of emergency a sample test can be done but floculation ( as a result of asphaltenes precipitation ) will take some time to settle.
Segregated storage should be preferred. If fuel contains excessive amount of asphaltenic sludge, the centrifugal separators may become clogged and proper fuel treatment becomes impossible.
Microbiological presence in fuel is perfectly normal.It needs water. Sulphur is known to be a lubricate improver and also an inhibitor for microbiological growth. FAME is another contributing factor. Microbiological growth gives viscous sludge affecting the running of purification plant.
There is no issue with HFO as microorganisms are killed with heating. Biocide is used for MGO with the following limits: Microorganisms may become resistant to biocide and some biocides may cause corrosion due to water acidification.
Taking off a maximum of water from the tanks is required. It is advise dto use biocide only in case of moderate to heavy contamination. B2200 has been identified as a non corrosive biocide.
MICRO CARBON RESIDUES
The carbon residue of a fuel ( MCR ) is the tendency of carbon deposits under high temperature in inert atmosphere. Diesel engine performance is lower when there are carbon residues. this property is included in fuel specification. But other factors can affect the combustion process in diesel engines ( engine loading, engine tuning, ignition qualities of the fuel ).
Engine manufacturer limit is 20% m/m. For fuel with High MCR , there is a risk to have carbon deposits in the turbo charger.
CATALYST FINE Al/Si
Cat-fines are almost as hard as diamond. They are composed of Al and Si oxydes. They have abrasive properties for engine components, piston rings and cylinder liners. Typical engine builder max limit will be 7-15 mg/Kg at engine inlet.
An efficiently fuel cleaning plant is the only practical way of ensuring that the contaminant particules are removed. Measuring Al and Si concentration before and after cleaning gives an indication of the efficiency but proper fuel analysis is necessary.
They are commonly referred as bio diesel
Bio derived fuels and blends of bio derived fuels with petroleum products are considered as alternative energy source as they are renewable and result in reduced greenhouse gases and SOX emissions. Limit allowed by ISO standard is less than 01% v/v but the level of FAAME in MGO available on the market may increase.
Additionally there are a variety of FAME products with different implications when it comes to storage, handling, treatment, engine operations and emissions.
The volume in MT should not be mixed up with the volume in CUBM. If product has a specific gravity of 0.88 , 1 liter weights 0.88 kilograms. The price per metric ton is obviously higher than the price per cubic meter.
1 barrel = 158.9872972 liters, So 1 barrel weighs 139.9 kilograms
So there are a little over 7 barrels of petroleum in a metric ton based on above gravity.
Contract to buy FUEL
Following items should be set up in a new frame agreement :
- Bunker Nomination
- Supplier’s obligations
- Transfer of Risk and Transfer of Title
- Supplier Warranties
- Quantity Measurements
- Testing of sample and Claims
- Payment Terms
- Termination of a Purchase Order
- Termination of the Contract
- Force Majeure
- Assignment and Delegation
- Books and Records
- Governing Law and Jurisdiction
- General Provisions
- APPENDIX templates
- Supplier Code of Conduct
- Product Specifications
- Bunker Delivery Note
- Bunker Nomination
- Firm Offer
- Invoicing Details
- QHSE Policies & Procedures
- Purchase Order (template)