VPS detected contamination utilizing in-house GC-MS (Gas Chromatography – Mass Spectrometer) analytical methodologies. [Image: VPS]
Raising disconcerting recollections of a string of incidents in 2018, main gas testing companies supplier VPS has recognized a brand new marine gas contamination problem in Houston. Eleven vessels utilizing this gas have now reported lack of energy and subsequent lack of propulsion whereas at sea.
VPS detected the presence of Dicyclopentadiene (DCPD) and related isomers at considerably excessive ranges in VLSFO bunker gas deliveries in Houston. These chemical contaminants had been detected utilizing in-house GC-MS (Gas Chromatography – Mass Spectrometer) analytical methodologies.
In a bunker alert issued to its prospects, VPS says the deliveries of contaminated gas had been made by a single provider throughout the months of March to May 2023. Problems related to these bunkers occurred after this gas was combusted a number of weeks after bunkering.
The results on the eleven vessels reporting lack of energy and subsequent lack of propulsion resulted from gas leakage within the ICU (injection management unit) models and gas pumps not having the ability to develop the required gas stress. Both primary and auxiliary engines had been affected though failures to auxiliary engines had been extra generally reported.
One VPS buyer highlighted the problems encountered when utilizing this Houston-bunkered VLSFO: the primary signal of issues after altering over to this gas was the failure of the gas pump and gas injectors of the auxiliary engines. All the three auxiliary engines subsequently confronted the identical points and had been unable to provide the required energy leading to an entire blackout and lack of propulsion. The auxiliary engine pumps exhibited vital leakage and the gas injectors had been seized. Both gas pumps and gas injectors required repeated alternative till no spares remained.
This buyer additionally reported that this gas had a major influence on the purification system. It was famous that the purifiers couldn’t take away the excessive cat fines that had been current within the gas beneath regular engine working pace. To preserve the air purifier operational, primary engines required operating at low rpm than regular, to cut back the gas consumption thereby lowering the air purifier feed-rate.
Due to restrictions in energy, the vessel had restricted maneuverability because it couldn’t function its thrusters. The vessel needed to change to LSMGO (low sulfur marine fuel oil) to reach safely to the port.
VPS says that DCPDs are unsaturated chemical compounds that may polymerize and oxidize beneath sure situations. However, the speed of this polymerization course of may be diminished by the presence of inhibitors which might be usually discovered inside gas oil.
Should these compounds begin polymerizing, the gas begins to exhibit a stage of stickiness and change into extra viscous, making it tough for shifting elements, comparable to gas pump plungers and the gas injector spindles to maneuver freely. These results trigger harm to the gas injection system. Over a time period extreme sludge formation is more likely to be skilled.
The DCPD compounds that had been detected on this gas ranged from 3,000 to 7,000 ppm (0.3-0.7%).
Quite a few vessels, had been pre-warned by VPS of the potential high-concentration DCPD contamination of their gas, by way of a “Caution” outcome from the VPS Chemical Screening service, highlighting the worth of this pre-burn service.
