By Aparajita Kapoor
May 20, 2019

Accounting for more than half of container ship operating costs, it is essential organisations take steps to manage water content in marine fuel, says Honeywell’s Aparajita Kapoor.

Around the world, the marine fuels sector is undergoing a period of change. New rules relating to emissions, introduced by the International Maritime Organization (IMO), have resulted in the development of alternative fuel types. Along with ongoing concerns regarding the quality of fuels, introduction of these new products is sure to see test labs servicing the marine industry kept busy in coming months.

Driving maximum value from fuel purchases is increasingly central to healthy bottom line, with marine fuel representing as much as 50 – 60 percent of a container ships operational expenditure. Unfortunately, with reduced freight rates continuing to squeeze margins, vessel operators are buying their fuel on a purely price basis, even when ‘cheaper’ products often carry inherent risk.

Grey practices by some unscrupulous fuel resellers, for example, can result in bunker fuel being bulked out with water, well above permitted limits stipulated by ISO 8217:2012. This not only means that vessel operators aren’t getting what they pay for, the excess water can also trigger costly handling and maintenance issues.

A 0.5% water level – which is the upper limit of the ISO specification – would amount to 5 metric tonnes in a 1,000 metric tonne bunker delivery. At a cost of around $800 per metric tonne, this is the equivalent of $4,000. Water removal can also lead to additional disposal costs plus, maintenance may be necessary to remove water-related sludge from the purification systems. There are therefore financial as well operational reasons to test marine fuel for water content via an independent lab.

With so much at stake, test labs need to ensure that they can offer their marine industry clients quick, accurate and reliable approaches for measuring the water content in bunkered fuel. However tests, even those as widely used as the Karl Fischer titration, are not straightforward.

Petroleum products are mixtures of long-chain hydrocarbons that don’t readily dissolve in methanol. Water determination using Karl Fischer titration therefore needs the addition of a solubiliser. Importantly, fuel oils are heterogeneous so any water content will be unevenly distributed so samples therefore need to be homogenised prior to testing.

Also, as a result of the low levels of water, it is important to use a titrant with a low factor – 1 or 2 mg/mL. To complicate things further, fuel additives can trigger side reactions during the titration process. Labs therefore need to ensure that they have reliable access to high quality solubilizers and reagents, ideally from a supplier that can also provide technical support and help with methods.

In a market experiencing depressed freight rates, the addition of expensive fuel changes will no doubt lead to many operators selecting the cheapest fuels available – a business decision steeped in risk.

It’s true that the practice of dishonest vendors supplementing fuel with water, beyond permitted limits, has been going on for some time. But with the sector suffering a period of reduced profitability, vessel operators can no longer afford the false economy of cheap water adulterated fuel.

Accurate fuel testing, therefore, is now one of the most important processes for ensuring the viability of marine business models. It is imperative operators partner with labs that can provide quick and accurate results. Doing so ensures the profitability of every voyage is maximised.