When a series of fuel burn issues began affecting vessels, VPS set to work identifying the cause

On 26 April 2018, Veritas Petroleum Services (VPS) issued a fleet-wide Bunker Alert. It had identified multiple vessels that had been affected by sticking fuel plungers, fuel-pump seizures and other failures when burning fuel oil bunkered in Houston, Texas.

The problem was known to be widespread and not limited to any particular supplier or barge; rather it was likely a potential upstream production or refinery issue, with the cause unknown.

After the initial Alert, the problem grew to affect at least 30 vessels in the VPS Fuel Analysis Programme, making it one of the most widespread fuel quality issues of recent years. Locating the source of the contaminant was a complex issue, with VPS’ statistics showing eight suppliers and 17 bunker tankers in the chain of supply.

VPS stationed a task-force across its laboratories, which undertook detailed forensic analysis of numerous samples from a range of vessels. It was critical that VPS identify which components were common to all the fuel samples and which had those physical properties capable of causing the problems experienced onboard its clients’ vessels.

The standard test methods within the ISO 8217 specification gave no clues to the underlying problem; it was necessary then to utilise additional VPS proprietary test methods to identify the cause.

By applying its in-house acid extraction gas chromatography–mass spectrometry method, phenolic compounds were identified as being present in each of the samples taken from vessels experiencing problems. The phenolic compound of highest concentration in all samples was 4-Cumyl-Phenol (CAS No. 599-64-4) – full name Phenol, 4-(1-methly-1-phenylethyl) – in the concentration range of 300ppm to 1,000ppm. VPS also identified high-boiling carboxylic acids (fatty acids) in some samples, but these were present at much lower levels.

4-Cumyl-Phenol has many industrial uses, including the manufacture of epoxy resins and as an emulsifier in pesticides, both of which utilise its adhesive (sticky) qualities.

Historical cross-checking of the VPS database highlighted numerous cases, dating back to 2007, where VPS had identified fuels containing phenolic compounds that had caused damage to fuel pumps and injectors, similar to the problems identified in this recent contamination scenario. The company also noted cases involving increased sediment levels at separators and filters and in some cases completely clogged filters.

The presence of this contaminant is in violation of Clause 5 of ISO 8217 which states: “The fuel should not include any added substance or chemical waste which jeopardises the safety or adversely affects the performance of the machinery; or is harmful to personnel; or contributes overall to additional air pollution.”

The analytical forensic investigation conducted by VPS will provide shipowners and operators with evidence of the presence and concentration of a phenolic compound within the fuel they bunkered.

Published on Marine propulsion