Maritime transportation is projected to heavily rely on Heavy Fuel Oils (HFOs) in the following decades. However, HFOs have a substantial impact on the environment, mainly because of the high sulfur dioxide emissions. The new regulation IMO 2020 limits sulfur emissions, reduced from 3.5 to 0.5 % by weight. In this scenario, our group began a research project aimed to tackle the issue of sulfur emissions.
u-ODS is a new patented technology that enables a sulfur reduction in Heavy Fuels such as marine HFO. The process involves the oxidation of sulfur through an oxidizing agent followed by liquid extraction. The main advantage of this process consists of the fact that it operates ad atmospheric pressure and low temperatures. The system relies on a novel ultrasound reactor which allows enhanced mixing and improved reactivity thanks to induced cavitation. The technology development started in a small becker with a laboratory-scale ultrasonic device and evolved into a continuous system that processes 1 ton/day of HFO. We obtained outstanding results at that scale, managing to bring sulfur concentration below the 0.5 % threshold established by IMO. We achieved those results by combining an empirical and theoretical understanding of the process through numerical models and several tests. The team is now involved in the construction of a 10 ton/day facility which combines all the experiences obtained from the smaller scales into a fully automated and state-of-the-art rig for oxidative desulfurization.