Gains from eco-lube switch
So far the oil washed overboard from hydraulic deck equipment has been largely ignored, but not for much longer – growing concerns about sensitive regions such as the Arctic and the stepping up of US regulations indicate the future in Europe and Scandinavia. But the smart answer is not to reach for the nearest green-stamped alternative: the choice needs to be made intelligently.
To start with, it’s no drop in the ocean. There is a “significant” amount of oil onboard workboats explained Dr Bernie Roell of RSC Bio Solutions: smaller hydraulic cargo cranes may require a few hundred litres of oil in the reservoir while an offshore crane like Hydramarine’s 100t knuckleboom can have 6,000 litres of hydraulic oil in the system. While most of it is retained, even a leak of one drop every two seconds could add up to 50 litres a month.
Added to this there’s the lubrication for the winches and so on: further, working vessels such as dredgers with mechanical buckets, grinders and conveyors and construction ships with pile drivers, drills and so on contribute their share of grease.
“It all gets washed overboard in rough seas or during deck cleaning,” explained Dr Roell, and said that at a guess, the accumulated yearly run off “probably comes to tens of thousands, if not hundreds of thousands” of litres.
The answer is an Environmentally Acceptable Lubricant (EAL). The US Environmental Protection Agency is setting the bar high: it’s VGP small craft rules will soon mandate the use of lubricants with a 60% biodegradation rate (into carbon dioxide and water within 28 days), a ‘minimally toxic’ impact and finally, only allow those that are non-bioaccumulative – that is, they won’t enter the food chain. Additionally, the US Clean Water Act disallows discharges which leave a visible ‘sheen’ on the water’s surface.
However, not all EALs are the same and a number have a couple of hitches. “There are other formulas, for example based on vegetable oils - but we don’t recommend them for marine use,” he said. “Vegetable, ester based chemistries have a weak link around the carbon-oxygen bond. Water... or heat... can break it down.”
“Likewise, water based polyalkylene glycols (PAGs) are least compatible with other formulas, including both esters and petroleum based products,” he explained. Any changeover means cleaning up the system entirely. “Oil and water don’t mix after all,” he pointed out.
By contrast, RSC Bio Solutions has pursued the Hydraulic Environmental Polyalphaolefins and Related Hydrocarbons family – HEPR for short. So, while Envirologic and Futerra series are not petroleum derived, they still share some important characteristics without being one of the bad guys.
As a result, hydraulic fluids “can operate in higher temperatures, up to 121°C” while it will also work in environments as low as -40°C. They also need to cope with high pressure workboat systems: as these can run at 3,500 psi the fluid has been developed to handle over 5,000 psi.
Some operators have bitten the bullet early – and found that rather than creating an issue, it actually had a positive impact. For example, Seaspan Marine switched over to EnviroLogic HF HP over two years ago, and found the change actually raised efficiency.
Dr Roell explained the effect: “It’s because the formula is derived from lower viscosity base oils: the lower the viscosity, the better it dissipates heat,” he explained. “There’s also less friction, providing longer equipment life and less maintenance.” He added that even when compared to conventional, petroleum-based hydraulic oils, this offers generally better wear protection and longer changeover intervals.
Usefully, the same products can be used across a number of different applications explained Dr Roell. However, for the heavy duty deck gear RSC Bio Solutions answer brings together a number of appropriate characteristics: it’s water resistant, having a good spray-off performance so it won’t just wash away, it has a good shear stability and can be used to protect ferrous and yellow metals. Despite all this, it’s still biodegradable.
By Stevie Knight
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