Viswa Lab has been testing numerous fuel blends called ‘Very Low Sulfur Fuel Oils’ (VLSFO) that are being introduced into the market to meet the IMO 2020 0.50% sulfur requirements. It is to be noted that these fuels are blends of several streams and the quality is dependent on various factors.
Ahead of this, various organizations (such as IMO, IBIA, MAN B&W) and suppliers (such as Exxon, BP, Shell) have been releasing several technical notes on how to handle these newer types of fuels to assist fuel users.
Recommendations about Handling VLSFOs:
This technical update is a summary of the recommendations available from different parties to educate the fuel users.
- ISO 8217 Specifications of the fuel (not ranges but the actual parameters of the fuel)
It is recommended not to source VLSFO’s without knowing the specifications to which the
supply is said to conform. Please ensure the below parameters are checked;
a. The parameters of fuel to meet ISO 8217 specifications.
b. Check for catfines – Follow handling procedures if catfines are found very high (settling, draining & proper purification)
c. Sediment content both organic and inorganic sediment.
d. Acid number and preferably also pH of the fuel.
e. Presence of Used lubricating oil (presence of Calcium, Phosphorus and Zinc)
f. Cold flow properties such as Pour Point
g. Flash Point - Source the fuel you wish to buy from reputable Fuel Suppliers
- Clean out tank residues as necessary. IMO has published a draft guideline about how to get the bunker tanks ready to take VLSFO’s (ISWG‐AP 1/2/11‐ Preparatory & transitional issues: Ship implementation planning for 2020)
- Segregate these fuels into tanks and avoid mixing
- Check compatibility between fuels whether it is VLSFO, ULSFO or MGO. If mixing is unavoidable, avoid blending in excess of the mixing ratio recommended by the Supplier or the Test Lab.
- Keep a close watch on the sludge generation at the purifier, filter etc. Purifier desludging
interval to be increased if the sludge quantity is excessive. - Pay close attention to the cold flow properties of the fuel as some of the fuels supplied in some regions could be paraffinic. This would result in deposition of large quantities of Paraffin in the tanks. This would mean that these fuels need to be taken into heated tanks (if available) with continuous heating and circulation capabilities.
- Some of these fuels may have lower viscosities (Viswa Lab has seen VLSFO fuels that had a viscosity of 2.5 cSt). Necessary heating/cooling protocols need to be adhered to make sure the viscosity is maintained as per the engine manufacturers limits. Ensure the fuel pumps are in good condition to handle variations in viscosities of the supplied fuels.
- Changes to cylinder lubrication needs to be made based on the reduced sulfur content in the fuel and as recommended by Engine Makers.
- Correct purification temperatures need to be known for proper purification of the fuel. Contact your lab to advice on the correct temperature to be maintained at the purifier for efficient purification purposes.
Shipping companies are relying on labs to provide appropriate information of the fuels that will be put to use. Viswa Lab has been in the forefront of analyzing and studying the properties of VLSFO’s to provide advice to the Customers (fuel users).
To assist with questions related to 2020 fuels Viswa has started and in‐house ‘Working Group’. You can reach them at wgfuels2020@theviswagroup.com
Please do not hesitate to contact them if you would like your VLSFO’s tested.
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Source: Viswa Lab
