Previously, most ship vehicles have used low-cost high-sulfur heavy fuel oil that is considered to be highly toxic when burned and difficult to treat when spilled, therefore, mounting evidence of ship emissions demonstrated the necessity to perform air pollution control in the industry.
Nevertheless, this type of fuel continues to be still used leading to acid rains and ship emissions but it has now some exceptions. According to MARPOL regulations, it is possible to use HFO if a ship applies an air treatment technology (for instance, the application of scrubber systems) to provide smokestack emissions that are equivalent to emissions produced by a compliant fuel like marine gas oil.
Nonetheless, some studies show that vessels with scrubbers installed on them burning HFO can not reach equivalent emissions as ships that simply apply cleaner fuels without a wet air scrubber. To be more precise, scrubbers are regarded as air treatment systems that enable shipowners to continue employing this low-cost fuel.
Herewith, some types of wet scrubbers can also lead to acidification and pollution in the marine environment. The operating principle of wet air scrubbers is based on directing exhaust gases into a chamber with a liquid solution/water (washwater) to take away sulfur oxides and other particulate pollutants before venting into the atmosphere.
It should be noted that three types of scrubber systems are distinguished. For instance, open-loop scrubbers (about 80%) discharge the used washwater right into the ocean, while closed-loop wet air scrubbers can save the used water and discharge it only in special places if required. Also, there is a hybrid type of wet scrubbers (17%) that can change open- or closed-loop mode.
Some scientists claim that scrubbers do not perform air pollution control, “they just transform it into water pollution.” The thing is that HFO’s gases include sulfur and nitrogen oxides that result in strong acid when they are put into water (more than 100.000 times more acidic than the seawater).
The possible solution to the problem includes compliance with scrubber system regulations, according to which it is forbidden to discharge the washwater from open-loop scrubbers at one or more of ports (24 countries adopted these regulations), for example, in Brazil, China, the U.S. However, some countries do not have such bans.
Redwood technology is a fast-growing vendor of wet air scrubbers. The multi-vortex scrubber can remove gas emissions, dust, vapors, and other pollutants from a gas stream. It is an innovative technology created to save water that makes it more cost-efficient and differs from other types of scrubbers. If you have any questions or would like to purchase a multi-vortex wet air scrubber, please contact us at firstname.lastname@example.org