Dr Fivos Andritsos of the Joint Research Centre of the European Commission has come up with an innovative solution to deal with oil spills that could be adapted not only to shipwrecks but also to oil-well blowouts by REBECCA PARSONS (Aug ’10)
His aim was to develop a system that could capture the oil right at its source, before it disperses on the surface of the ocean. The solution was developed during the European funded project DIFIS, an acronym that describes the device itself: a Double Inverted Funnel for Intervention on Shipwrecks.
Which is the basic idea lying behind of your project?
The basic idea behind DIFIS is very simple, in fact it’s so simple that we were surprised when we did our patent search that nobody had thought of that before. You anchor around the wreck a dome which is like a funnel. So whatever leaks you have on the wreck, they flow upwards by gravity.
How does it work?
The oil travels up a riser tube, which is roughly two metres in diameter, wide enough to avoid any clogging, until it reaches a bell shaped reservoir, the “buffer bell”. This buffer bell is the key to the whole system. It separates oil from water by gravity, letting the water escape from the open bottom of the bell. It’s buoyant, so it holds up the entire structure including the dome and the riser tube. And it’s large enough to store thousands of barrels of oil until a tanker arrives to off-load it. Crucially, the bell lies well under the water, protected from storms and the force of the waves.
Once in place, it is completely passive, you leave it there. There are no pumps operating, nothing. You don’t need to have vessels that’s stationed on top of the wreck. Nothing, just leave it there, and once in a while you go and empty the buffer bell.
Can the system be deployed also in deep water?
The difficulty is to deploy the system and anchor it strongly around the wreck in very deep water, several kilometres below the surface. The deeper the shipwreck, the more complicated and expensive it becomes to put the structure into place. I would say that the optimum operational depth is anything from 500 metres to 2000 metres. But, it’s just a matter of cost, going towards much deeper depths.
Is this solution ready for use?
Thanks to the work of the consortium, the design of the structure has been considerably refined and modified for optimum efficiency, and there are now several working strategies for installing the device. Now we have a very solid engineering design, not just an idea, with dimensions, costs, deployment procedures, other operational procedures, although, of course, there’s no full scale prototype. Opportunities for testing a full-scale prototype abound. There is no need to wait for the next disastrous oil-spill! There are thousands of wrecks worldwide, mainly from the two world wars, and it is estimated that the oil trapped in their reservoirs, in their tanks, can be anything between two million and twenty million tonnes. Now, most of these wrecks, now 60 years after the second world war, start becoming unstable because of the corrosion, 60 years in the water. Corrosion slides. There is a risk that oil starts flowing up from these wrecks. Some of these wrecks are placed near ports or coastlines that have significant tourist and commercial activities, so they undoubtedly constitute a threat.
What about adapting DIFIS for oil-well blowouts, such as the BP disaster in the Gulf of Mexico in 2010?
On the applicability of DIFIS to oil-well blowouts, we think after values, after examining the whole situation over the past two months that DIFIS would be, perhaps with slight reengineering or adaptation, would be ideal to deal with the system. Not permanently, but give time, perhaps many months or even years, for the experts to intervene and make a permanent solution via the side drillings.
(2 August 2010)
Rebecca Parsons