Sulfaway Executive Summary

ULFAWAY project aims to study in lab scale and prove the concept of a novel desulfurization methodology of heavy fuel oils, which complies with the “technology/ know-how applications (engineering and
technology) related to the hydrocarbon sector”.



The general objective of the SULFAWAY project is the development of an innovative process for the oxidative desulphurization (ODS) of the heavy diesel oil that is used in the marine industry. In October 2016 the International Marine Organization (IMO) committee set January 1st, 2020 as the starting date for the new MARPOL (Marine Pollution, the International Convention for the Prevention of Pollution from Ships) bregulation, where new limitations have been introduced concerning the msulphur content of the fuel oil used by ships in order to prevent pollution originated from the marine industry. More specifically, all ships that are operating outside the designated emission control areas (ECAs) must use fuel oil with only 0.50% m/m (mass to mass) Sulphur content; significantly reducing the sulphur content compared to the former limit of 3.50% m/m sulphur content. Since the majority of current fuel oil does not meet the 2020 standards, lowsulfur fuel oil and other distillates, such as MDO, will see demand increased. The current global average of sulfur content in heavy fuel oil (HFO) is above 2.5 percent, and with the new regulation, at least 80 percent of this will have to be removed, or a way must be found to dilute it with very low-sulfur-content fuels.

The proposed SULFAWAY concept (Figure 1) is based on the oxidative desulfurisation (ODS) by which an oxidative reagent, most commonly hydrogen peroxide (H2O2) is used to oxidise the sulphur-containing molecules to sulfoxides or better to sulfones. Then, these compounds having different chemical behaviour than the “parent” compounds, will be removed by liquid-liquid extraction with suitable extraction solvents such as the deep eutectic solvents. In the field of DES, the HO has gained great experience by coordinating the REGFILT project (CONCEPT/0618/0065) which dealt the regeneration of DPFs incorporating DES based, biodegradable solutions.  

The realisation of SULFAWAY will reinforce the capacity of the company to provide a holistic sulfur reducing technological package which will be realised by the combination of its projects according to two pillars i) SULFAWAY project aiming to reduce sulfur content in the HFO used as fuel in the marine sector; ii) CATMAR project, under which a SOx emission reducing device has been developed. Thus, while SULFAWAY can itself almost eliminate Sulfur emissions, its combination with CATMAR technology ensures that the marine sector can totally be SOx emission free.

Existing Knowledge-Project Innovation

The large number of ships that are operating worldwide use heavy fuel oil as fuel. The main reason that the HFO (Heavy Fuel Oil) is widely used by the maritime industry is its lower cost than all other fuels because it does not receive any further purification. HFO is injected in the internal combustion engine of a ship and after ignition the fumes are driven towards the chimney and released to the atmosphere. These fumes, apart from CO, CH4, NOx and particulates consist also from sulphur-based species, mainly sulphur dioxide (SO2). Sulphur oxides emissions originated from ships is of great importance concerning health and environmental benefits for the world, and especially for populations that live close to ports and coasts. It was estimated that in the year 2000 SO2 emissions from shipping were around threefold greater than that from all road traffic and aviation combined. Sulphur oxides are harmful to human health and in parallel, sulphur oxides (SOx) emitted to the atmosphere, can lead to acid rain, which impacts crops, forests and aquatic species and contributes to the acidification of the oceans.

The International Maritime Organization (IMO), since January 2020, has introduced new limitations concerning the sulphur content of the fuel oil used by ships in order to prevent pollution originated from the shipping industry. All ships that operate outside the designated emission control areas (ECAs) must use fuel oil with only 0.50% m/m (mass to mass) Sulphur content; significantly reducing the sulphur content compared to the former limit of 3.50% m/m sulphur content, while maintaining the limit of 0.10% m/m sulphur content of the fuels that ships are using when operating within ECAs (Baltic Sea, the North Sea, the North American area and the US Caribbean Sea area). At the same time, according to the International Energy Agency, the oil demand is continuously growing until 2030 due to the dynamic increase of China’s and India’s demanding (Figure 3). Even though alternatives to oil have been used the last decade, like natural gas, the era of oil is not over yet as it is used in most automotive vehicles, aviation, shipping etc.

The origination of SOx is based on the sulphur-containing compounds that can be found in the heavy fuel oil, which is the leftover of the fractional distillation of oil and is highly used by the maritime industry due to its significantly lower price. More specifically, heavy oils contain almost 3.5% of sulphur containing compounds that cannot be easily removed by the conventional methods of desulphurization. For example, in the hydrodesulphurization process (HDS), the heavy fuel is mixed with hydrogen and a catalyst to reduce Scontaining molecules to hydrocarbons and hydrogen sulfide (H2S). Despite the high operational cost of this process (high-pressure reactors for H2, high operating temperatures, etc.), HDS is limited in hydrogenation of low-molecular weight thiols and to less sterically hindered thiophenes.


The HO has designed the implementation plan in order to achieve the best outcome from the SULFAWAY project by successfully completing all objectives. The proposed methodology includes five (5) distinct work packages that covers the whole range of the project’s activities, from the management to the dissemination to the implementation and can be summarized in the next scheme.The Project Management work package m(WP1) will be running for the whole duration mof the project ensuring the successful mimplementation of all tasks and the quality of
the work and documentation, keeping thescientific team within the timelines and more. Samewise, the dissemination work package (WP2) will be undertaking dissemination activities within the duration of the project, beginning with the dissemination plan and the project website, which will be updated with the news from the project’s progress and results. WP3 and WP4 concerns the technical part of the project; WP3 deals with the research and development of the process of the proposed methodology (i) research based on the oxidation step of the sulphur-containing compounds, (ii) development of the DES solutions, (iii) extraction of the oxidized S-compounds from the DES solutions and (iv) optimization of the parameters of the above procedures. On the other hand, WP4 will deal with the removal of the extracted compounds from the DES solution, the recyclability of the DES solution and the possibility to reuse the solution for more than one extraction round.