Finnish cleantech company Valmet says that it has tested a first-of-a-kind exhaust gas treatment system (scrubber) and wet electrostatic precipitator combination which is capable of cutting exhaust gas emissions from a marine diesel engine by up to 99%.
Valmet believes the solution could allow shipping companies to lower their particle matter (PM) and black carbon emission levels, tackle global warming and comply with tightening regulation. The pilot testing and configuration project was carried out together with VTT Technical Research Centre of Finland.
Hitherto, IMO regulations on air pollution have addressed mainly SOx and NOx emissions but the awareness of PM and black carbon emissions is growing due to their negative impact on global warming and human health. Whereas SOx scrubbers can reduce PM and black carbon emissions with limited efficiency, a combination of a wet scrubber and a wet electrostatic precipitator could capture these emissions almost completely from a ship’s exhaust gas.
VTT Senior Scientist Kati Lehtoranta said: “At VTT, we had already studied the emissions of ships that have a marine scrubber installed. This way we had experience of the challenging measurement conditions related to scrubbers and also comparable data on the emission reduction potential of the new setup.”
Additionally, VTT had a medium-speed diesel engine that runs on heavy fuel oil, the equipment for demanding pilot tests, top experts and the scientific know-how to publish the test results.
Juha Jokiluoma, Product Manager, Valmet, said: “The solution we tested brings so many benefits that we believe it has great potential. Emission regulations are bound to tighten in the upcoming years. Valmet now has a solution that can be installed both on newbuilds and already operating vessels that still use conventional fuels. That enables shipping companies to significantly reduce particle emissions, while continuing their operation normally.”
The Valmet Wet Electrostatic Precipitator – WESP, or Wet ESP – is used to control emissions, including particulate emissions, heavy metals, acid mist, oil mist and visible plume. Its operation is based on a very strong electrical field between discharge electrodes and collecting tubes created by a transformer rectifier. Valmet WESP can be integrated to Valmet DNA’s user interface or other distributed control systems as well as utilise new Valmet Industrial Internet (VII) features.
Valmet offers two basic types of marine exhaust gas scrubbers. Its open loop scrubber uses seawater as wash water, and its closed loop scrubber circulates the wash water and uses alkaline chemicals to capture sulphur. A hybrid scrubber combines both operation modes and can easily switch between the open and closed loop operation modes. Valmet says it was the first company to introduce this new-generation hybrid scrubber. The wash water from both the scrubber and the WESP systems can be efficiently treated in the Valmet Water Treatment System (WTS) to fulfill the IMO regulations.
Valmet has developed scrubbers since the 1970s and delivered more than 300 scrubbers onshore and offshore.
VTT is a visionary research, development and innovation partner. VTT drives sustainable growth and goes beyond the obvious to help the society and companies to grow through technological innovations. VTT has 80 years of experience in research and science-based results.
