I got an email today from ABS letting me know that they have a publication on the new rules from the IMO to be activated in Jan, 2020. One of the main concerns is the use of diesel containing high amounts of sulfur in cargo ships. The emission is known as SOx. It comes out the smoke stack and gets converted into acid in the atmosphere. Hmmm, sounds bad.
Nevertheless, aside from using diesel with very low sulfur content, the IMO allows a ship to use something called an “open loop system”. This system uses a “scrubber” (essentially a device that transfers the SOx from the exhaust to seawater). Seawater is used in the scrubber, the SOx is transferred, then the seawater is dumped back in the ocean. As my old inorganic chemistry professor would say, “how do you like them ‘scimoles’?” I honestly do not see how this helps anything.
You can read the ABS publication, 2018, here. https://ww2.eagle.org/content/dam/eagle/advisories-and-debriefs/marine-fuel-oil-advisory.pdf