Quote:
Originally Posted by MetroMPG
Insulting forum members isn't acceptable. Cut it out, please.
(Edit: to clarify, this is directed at litesong.)
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Back to the topic at hand.
Last year, while cruising to and from Bermuda, I had the opportunity to converse with the Environmental Officer of the ship. It was informative and uplifting. Such that he held a daily "coffee shop" discussion with anyone interested in the subject. It was well attended by a broad range of age groups and educational/professional backgrounds.
Of great interest to me was the technology the cruise line had decided upon to meet the coming low sulfur fuel edict. Some countries were enacting laws that required low sulfur fuel only while within a specified range of their lands. These were reasonable laws since sulfur dioxide is quickly dissolved into the sea water. Most ships have several fuel bunkers and a simple retro-fit of a bunker to carry and dispense low sulfur diesel adds little to operational costs. The requirement to run low sulfur fuel the entire trip would be cost prohibitive. Thus, a version of coal scrubbers was ready to be installed on their liners. It is a simple baffled mixer with a spray of water coursing down dissolving the sulfur into the water shower. Thus, the smoke stack emissions carry low single digit percentages of sulfur than before treatment. The sulfuric acid in the cleansing shower is neutralized by crushed limestone to form calcium sulfate.
Depending on the length of a cruise cycle, the last portion - the acid neutralization - could entail a considerable bulk of crushed limestone. However, it was not seen as overly problematical. For every 1000 tons of bunker fuel burned only a few tons of crushed limestone would be consumed in the neutralization step.
The calcium sulfate has value as an ingredient for plaster. Though the volumes produced would not be great.
Additionally, there was talk of simply dispensing the used limestone overboard as calcium sulfate is already found on the ocean floor. However, there was a vociferous group in attendance who felt nothing should go overboard. I'm quite sure tradesmen in Bermuda would have liked a few tons of free plaster.
https://www.shipownersclub.com/metho...sulphur-limit/