With increased levels of FAME being allowed in the EN590 Gas Oil (#2 Diesel) specification, the presence and concentration of FAME components in these cargoes might not be known by the vessel. This could create a major problem if a subsequent cargo is Aviation Fuel. Current Jet Fuel specifications have a very low tolerance to FAME and, although not currently reflected in specifications, AVGAS can also be critical with regard to FAME as noted within the Energy Institute publication HM50 Guidelines for the cleaning of tanks and lines for marine tank vessels carrying petroleum or refined products. (HM50) Companies are sometimes asked to inspect ships tanks for cleanliness previous to receipt of cargo and to issue a respective Tank Inspection document. With increasing environmental restrictions, many of these inspections should be performed from deck level only as the tanks remain under inert gas. Any retained cargo have to be determined by manual gauging and sampling through vapour control valves. It is therefore essential to rely heavily on information provided by the vessel as to previous cargoes and tank cleaning methods. While IFIA members can review records of previous cargoes and tank cleaning methods they can’t attest to the accuracy of data provided by the vessel and clearly this could also be critical in relation to FAME contamination of Aviation Fuel. IFIA members should report the conditions under which tank cleanliness and/or OBQ is determined and note where information is provided by the vessel. There’s an inherent problem in obtaining uncontaminated samples from cargoes which follow Bio diesels as FAME has a tendency to adhere to internal surfaces. This may occasionally result in increased concentrations at sampling points, as they are difficult to wash. HM50 states under section 2.12.7 that the cleaning regime employed by the vessel should include sampling equipment, stand pipes and stilling wells. However, the Inspector normally has to rely on cleaning information provided by the vessel and can’t verify whether this operation has been carried out. When a previous cargo has contained FAME and samples are drawn through the vessel sampling system their integrity could also be in doubt because of the inherent difficulties in removing FAME residues from sampling fittings on the vessel. Therefore, in cases where analysis of samples obtained via closed or restricted systems indicates that FAME limits have been exceeded in a following cargo, it is recommended principals are advised accordingly and arrangements are made to take additional samples under open sampling conditions to confirm the outcomes. The responsibility for cleanliness and suitability of the vessel rests with the vessel and its charterer. It is suggested that charterers confirm whether FAME has been present in previous cargoes and be certain that appropriate cleaning procedures are adopted previous to considering the vessel for the carriage of Aviation Fuel. Where part cargoes are involved charterers should treat any non-nominated cargo tanks carrying FAME or Bio diesel in the identical manner as the nominated cargo tanks to avoid the potential for cross-contamination. HM50 recommends three intermediate cargoes between FAME or Bio-diesel with a FAME content of 15% or above (B15) and an Aviation Fuel cargo, along with rigorous cleaning procedures for prior cargoes with lower FAME levels. IFIA members would consider the presence of FAME or Bio diesel in the three prior cargoes a reason to decline the vessel as fit for the loading of Aviation Fuel. Therefore, it is suggested that any charterer choosing to utilize such a vessel should inform the Inspector of its agreements with the vessel upfront of its arrival for inspection to reduce the possibility of delay. There is significant evidence to show that shore loading systems can retain enough residual FAME to contaminate an Aviation Fuel cargo. It’s therefore recommended that the party with contractual responsibility for the loading operation verify with the terminal that manifolds, loading arms and hoses haven’t been used to transfer FAME or Bio diesels for the last three operations. IFIA members usually are not in a position to acquire and verify such information and cannot accept any duty or responsibility on this regard.
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