Dangers of Contaminated Fuel


The shipments of contaminated bunker fuel have made their way to several bunker ports in different countries. The International Association of Independent Tanker Owners (Intertanko) and shippers worldwide have called for a stricter quality control.

No reports of the dirty bunker fuel entering the Philippine ports till date. Still, the news caused alarm and concern among local shippers says an article in Manilatimes.

How and where it started?

The first report came from the U.S. Gulf Coast, with subsequent occurrences in Panama, Malaysia, and Singapore in a span of a few months.

It still remains clueless as to how or where the shipment of contaminated bunker fuel started.

What is bunker fuel?

In layman’s term, bunker fuel is defined as any fuel that is poured to the ship’s bunker to run its engines.

Bunker fuel is usually graded as A, B, or C, with C being described as the most viscous and most difficult to work with.

What aggravated the issue?

The problem in Singapore has caused significant headache, as the country is considered the world’s largest refueling hub for ships.

The problem is further exacerbated by the fact that Singapore exports bunker fuel to all ASEAN countries including the Philippines.

Dangers of contaminated fuel

Pouring tainted bunker fuel might allow the ship’s engine to run for a short while. But, as one expert in petroleum chemistry says, it can cause several issues that can lead to, “catastrophic failure”.

The expert says that contaminated fuel can lead to a number of mechanical issues. The engine may experience reduced fuel atomization.  And this will often lead to increased fuel consumption, which will end in increased emissions and soot generation within the (engine) cylinder.

Contaminated fuel can also cause valve erosion which often leads to fuel leakage, which then results in localized hot spot generation and loss of engine power and full functional failure point.

In the case of the recent fuel contamination in Singapore, it resulted in severe sludging which caused the ship’s pipelines to be clogged. The affected ships had no choice but to conduct an extensive fuel flushing and subsequent costly engine repairs to address the damage the dirty fuel caused.

No fuel is 100% pure

According to a chemist specializing in petroleum products, it is not entirely plausible to have “100% pure” fuel.

Fuel, regardless of whether it is bunker oil or much lighter hydrocarbon (e.g. diesel, gasoline), contains trace amounts of contamination.

However, there is a limit set for such contamination. In the Philippines, the contamination in bunker oil can be tested by using either the Philippine National Standards (PNS) or ISO 8217 Fuel Standard for Marine Distillate as a guide.

What makes fuel ‘dirty’?

“The contamination can come from improper storage or tank maintenance. It can also come from blending. For example, Grade C bunker oil is often mixed with 10% of diesel (or another similar lighter hydrocarbon) to make it flow better. The blending also pulls the price [of the bunker fuel] down, which attracts ship operators to buy that particular product,” the expert explained.

He said that the problem is, it is almost impossible for a consumer to determine if the bunker fuel is contaminated or not based on visual inspection. Whereas, it is easy to determine the quality of lighter hydrocarbons, by checking its color and transparency.

The question is why not just use an unblended bunker fuel? The expert said it is almost close to impossible as there’s already a directive from International Marine Organization (IMO) to reduce the percent mass of sulfur content from 3.5% to as low as 0.5%. The only way to comply with the directive is to increase blending to bring down the sulfur content to their desired new limit.

Test results

Chemical test results reported that the contaminants found in Singapore samples are Estonian oil shale and fracked shale oil from the U.S.

An oil shale is a type of organic-rich fine-grained rock where oil is commonly extracted. Oil shale should not be confused with shale oil, which is oil trapped in shale formations and are usually extracted by fracturing the rock surrounding the oil.

First step for prevention

Although there are fuel standard regulations set by the IMO, it is still challenging to identify contaminants. One of the things an average person can do is to send a sample of bunker oil to a respectable third-party testing laboratory for analysis.

This can give both the customer and supplier the confidence that the bunker fuel they are purchasing/selling is of good quality.

While this might seem like an unnecessary expense and delay to both consumers and suppliers, pre-testing bunker fuel is a necessary evil to prevent more costly repairs and de-bunkering due to contaminated fuel.

GC-MS Analysis

Pre-testing cannot fully guarantee that a vessel is indeed getting untainted oil. After all, the contaminant might be something that a standard chemical test cannot pick up.

A standard bunker fuel quality testing often includes determination of ash and carbon residue, sulfur content, total sediment potential, and water content. It also include determination of bunker fuel density, flashpoint, and viscosity.

Standard pre-testing might not pick up specific chemical contaminants such as styrene and phenol. Thus, it might be more reasonable to send a bunker fuel sample for an analysis using Gas Chromatography Mass Spectrometry (GC-MS) to obtain the complete list of contaminants and their respective percentages or concentrations.

How to spend sensibly?

Having this kind of knowledge is highly advantageous specifically for ship operators. Unfortunately, using advanced laboratory equipment comes with a steep price.

A single sample run can cause a few hundred dollars. Still, the cost of analysis using GC-MS is significantly cheaper than using potentially dirty bunker fuel and damaging a ship’s engine in the process.

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Source: TheManilaTimes



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