Over the past few weeks, we have seen a number of cases of increased Potassium content in the bunker fuels supplied in US Gulf ports of New Orleans, Galveston and other Houston area ports. There were 4 cases where the Potassium content was over 100 ppm (102ppm, 103ppm, 131ppm and134 ppm)
Potassium can show up in bunker fuels as a result of the carryover from the refinery treatment to scavenge H2S. Some refineries use KOH instead of NaOH. Excess Potassium can also come from shale oil cutter stock.
There is no limit specified in ISO 8217 for potassium. The effect of high potassium is somewhat similar to sodium with elevated exhaust temperatures, deposits on turbocharger blades and nozzles, reduced turbocharger speed and reduced engine output.
Effect of High Potassium in Bunker Fuel.image Credit: Viswa Lab
We recommend that caution be exercised if the potassium content exceeds 50 ppm. If you are caught in a difficult situation, you could consider blending with another compatible fuel to bring down the potassium content. Water washing during purification process can also remove substantial amount of potassium in the fuel. In addition, magnesium‐based additives may mitigate the problem.
If you are bunkering in US Gulf ports, you must insist on a bunker analysis report and assurance from the supplier on the potassium levels.
To assist with questions related to 2020 fuels Viswa has started and in‐house 'Working Group'. You can reach us at firstname.lastname@example.org
Please do not hesitate to contact us if you would like your VLSFO's tested.