As part of a series of articles released by The Economist in early January 2009 entitled the Survey of the Seas, one of the most concerning themes (and there were many) surrounded the quickening of the melting of the ice caps; luring more ships to utilise the northern shipping routes later into Autumn and earlier in Spring.

To quote an extract: “A new seaway through an unfrozen Arctic Ocean would cut the journey from Rotterdam to Yokohama via the Suez Canal by 4,700 miles, a saving of 42 percent.  From Rotterdam to Seattle via the Panama Canal, the saving would be 2,000 miles, over 20 percent. Ships too big to go through the Panama Canal would save even more.”

For a cruise industry introspectively seeking answers to how it becomes 'greener' whilst sustaining and expanding its lucrative sector, it is worth noting that recent studies concluded that levels of back carbon, or soot, in the Gulf of Alaska were 40 percent higher than other regions due to its proximity to shipping lanes.

Soot does not travel more than a few hundred miles but is the major contributor to blackening ice caps and reducing the 'albedo effect' reflective process of the ice - accentuating the progression of global warming.

Black carbon provides further context for the significant changes made to IMO MARPOL Annex VI legislation in October 2008, which effectively sanctioned the end of significant levels of sulfur oxide in marine fuel.

Two options were approved: a phase-out switch to 'cleaner' distillate marine fuel or fitting a marine scrubber system.

Both options would all but remove shipping's near 30 percent contribution to global sulphur oxide emissions by 2025, but only scubbing would significantly reduce the 133,000 tonnes of black carbon-causing particulate matter emitted by ships and limit the extra energy and emissions required to create sufficient distillate fuel at refinery.

Seawater scrubbing systems, such as those manufactured by Krystallon, are a manifestation of long-used land-based scrubbing systems. Scrubber systems have been used for years to remove particulates and gases from industrial exhaust streams and  for  forty years on tankers as Inert Gas Generators. Traditionally, the term "scrubber" referred to pollution control devices that use liquid to wash unwanted pollutants from a gas stream.

The term 'scrubbing' is also used to describe systems that inject a dry reagent or slurry into a dirty exhaust stream to "wash out" acid gases, such as those used by other marine scrubber developers.

Krystallon's seawater scrubber, the first marine application in full operation, is manufactured from high alloy steels specifically developed for the application; fitting into the funnel space being both lightweight and self-supporting. The scrubber is designed to run cool, operating on seawater, although, under emergency conditions, it can be operated at temperatures of up to 450 C without failure. Systems typically silence the exhaust noise, while removing 100 percentof SO2 and up to 85 percent of particulate matter when operated on a 35,000 ppm, or 3.5 percent bunker fuel.

A washwater treatment system is designed to handle the full scrubber water flow and is designed to remove both the solid particulate and liquid hydrocarbon waste products. A very efficient design reduces contamination to levels measured in part per billion.  

Extensive studies have shown that washwater sulfur levels increase by only one part per million upon release into the sea – no effect upon the ocean's natural sulphate content of around 900-950ppm even before dissipation.

While the emission reductions achieved by the system from four current Krystallon installations – including a scrubber fitted onboard the Holland America Lines' 60,906-ton Zaandam - supersede those of distillate fuel, so do the costs of the system relative to switching fuels.

The current premium for 1.5 percent low sulfur bunker fuel in Rotterdam averages around $40 per tonne over high sulfur bunker fuel, that premium is set to rise from July, 2010, when the next phase of Annex VI is applied to the North and Baltic Seas at 1.0 percent sulfur. In North America, a 1.0 percent or 0.5 percent ECA will likely apply from 2011.

Savings from 2015 for operators using ECAs will be significant; Marine Gasoil in Rotterdam was pegged at $460.50 per metric tonne, according to Bunkerworld on the day of writing – 88 percent higher than IFO380 standard bunker fuel. Payback for marine scrubbing systems can be anywhere between one year and four years depending on a ship's routing.

While other transport sectors grapple with reducing levels of CO2, shipping should consider replicating what land-based utilities in developed nations achieved decades ago and remove sulfur and particulate matter pollutants both swiftly and cost-effectively.  

(Submitted by Krystallon.)