Laboratory station for research of the innovative dry method of exhaust gas desulfurization for an engine powered with residual fuel
Authors: KORCZEWSKI Zbigniew , RUDNICKI Jacek , ZADRĄG Ryszard 
Published: March 2021

Development of technology for exhaust gas desulfurization in marine engines using the dry method is, nowadays, a priority due to the calendar of introducing restrictions by the Directive of the European Parliament and of the Council 2012/33/EU of 21 November 2012. According to this directive, starting from 1 January 2015, inside the SECA (Sulphur Emission Control Area) the maximum sulfur content of marine fuels used on territorial seas is 0.1% per weight unit. But at the same time the directive allows for the use of exhaust gas desulfurization plant operating in a closed system. The ship equipped with the system will be able to use fuels with a high sulfur content, which will then be removed from the exhaust gas through an applied adsorber, and the reacted adsorbent is received by specialized services stationed in harbors. The International Maritime Organization has set a limit value of the emissions of sulfur oxides in exhaust gases of marine engines at 6 g/kWh (International Convention for the Prevention of Sea Pollution from Ships MARPOL 73/78 Annex VI, Regulation 14).
Contemporary methods of exhaust gas desulfurization in marine engines are all expensive methods (4-5 million euro). This is, among other reasons, due to the limited market audience, but primarily due to the monop-olized position of manufacturers offering fabrication and assembly of this type of marine ship installations. Proposed as part of a research project financed by the Regional Fund for Environmental Protection and Maritime Economy in Gdansk, the dry method (adsorption) reducing SOx emissions in exhaust gases of marine engines, is an alternative, and a definitely cheaper and therefore competitive solution, compared to the wet methods (absorption), which are currently the most widely used in marine scrubber installations. Importantly, as confirmed by the results of the study, the proposed dry method, in addition to the effective reduction of sulfur oxides, also reduces emissions of nitrogen oxides and carbon monoxide. The paper presents the configuration and measurement capabilities of the test station built under the project, as well as the representative results of the investigations so far. During the exhaust gas desulfurization test a sodium adsorbent (sodium bicarbonate) and its modifications were used in the process of mechanical, chemical, and thermal activation. Two physicochemical processes were studied during the development of the method: • of adsorbent’s reaction on the chemical emission of the exhaust gas – the effectiveness of SOx and NOx compound removal, with various structural solutions in the process reactor, • the impact of the adsorber on the emission source of sulfur oxides, that is, on the compression-ignition engine. Therefore, one of the priorities of the project, with a utilitarian significance, was to determine the impact of the inclusion of the desulfurization installation in the exhaust gas system on the energy ratios of the engine.