Emissions of SOx are solely a function of the sulphur content in the fuel burnt and cannot be influenced by the engine builder using primary measures in the combustion chamber. Thus, only secondary measures are available to combat SOx i.e. fuel conditioning and after treatment. Using heavy fuel oil to benefit from the prize gap to low sulphur distillates requires an after treatment measure, which is able to not only meet the legislation but also allows to very economically operate a vessel. A proven way of after treatment is the absorption of SOx in reactors using limestone. The DryEGCS^® is reaching an efficiency of about 99%. The DryEGCS^® technique is neutral to the exhaust gas temperature and allows the operation of the SCR in the cleaned exhaust gas afterwards.

The constant high temperature level of the DryEGCS^® permits the installation at the bottom of the vessel which gives advantages regarding stability and impact on cargo space. The reactor itself contains the packed-bed granulate. The exhaust gas passes through the absorber and the SOx reacts with the granulate (limestone) to gypsum. The granulate runs through the system by gravity and is extracted as residue on a frequent basis.

The residues can be stored i.e. in spare rooms within the hull which allows an optimized installation to reduce the impact on valuable spaces like cargo or passenger areas onboard of the vessel. In the harbor, the residues will be replaced by fresh granulate. The discharged residues are disposed of to land-based applications i.e. power plants where they are used as valuable consumable additive in the burning process.

MAN Diesel & Turbo offers the DryEGCS^® which removes the sulphur permanently from the biosphere. DryEGCS^® − another important step to a greener future.