Scrubbers – An economic and ecological assessment
Germany's Nature and Biodiversity Conservation Union (NABU) announced the results of a study it says shows that "scrubbers are no solution to air pollution from ships." The recent tightening of the fuel sulphur limits for fuel used in Sulphur Emission Control Areas (SECAs) requires the use of fuels with a maximum sulphur content of 0.1% in these regions, or a technology that can reduce emissions to an equivalent level, from January, 1st 2015. Most low sulphur fuels are distillates (e.g. marine gasoil MGO, which are more expensive than the residual fuels that are traditionally used by ships (e.g. heavy fuel oil HFO)). Exhaust gas scrubbers, in combination with the use of HFO, have been accepted as an alternative means to lower sulphur emissions. Four different types of scrubbers are available today: Seawater scrubbers (open loop) utilize untreated seawater, using the natural alkalinity of the seawater to neutralize the sulphur from exhaust gases. Freshwater scrubbers (closed loop) are not dependent on the type of the water the vessel is operating in, because the exhaust gases are neutralized with caustic soda, which is added to freshwater in a closed system. Hybrid scrubbers give the possibility to either use closed loop or ...
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