Dual SCR systems retrofitted on cruise ship

The retrofit integrated an SCR system into both of the Amadea’s four-stroke MAN 7L58/64 propulsion engines. For the project, MAN PrimeServ prioritised keeping hazardous emissions to a minimum while maintaining engine performance and propulsion efficiency.

The Amadea project required steel work to free space for installation of the SCR systems and ancillary units; the modular SCR system typically installed aboard newbuildings was not 100% transferable to a retrofit and required some adjustments in the case of the Amadea. Mechanical and electrical integration, and system parameterisation, also required some resources.

MAN PrimeServ Augsburg previously retrofitted the Amadea’s turbochargers – in the process improving engine efficiency and significantly reducing CO2 emissions. The combined work carried out on the vessel reflects MAN Energy Solutions’ desire to increasingly become a supplier of complete propulsion solutions.

The MAN SCR solution has brought the Amadea’s engines from Tier 0 status to Tier III emission level, and has reduced NOx emissions by 90%, equivalent to savings of 600 tons per annum. The SCR will be available from just 15% engine load, enabling clean operation during slow-sailing in the fjords as well as close to port and populated areas.

The fully modular SCR solution has also been fully integrated into the Amadea’s engine-control set-up. With its closed-loop system and a weather station that uses environmental data, the NOx-reduction rate is maximised and ammonia-slip minimised to just 10 ppm, comparable to that of a car. This reduces urea consumption, enabling the urea-tank size to be minimised.

A feasibility study by MAN PrimeServ at the project’s beginning confirmed the compact, modular SCR system’s suitability for the limited space available aboard the vessel. Its integration into the narrow funnel is only possible due to the special 87cpsi honeycombs and their high reactivity in a two-layer slim reactor design.

Bernd Siebert, Head of Retrofits & Upgrades, MAN PrimeServ, said: “This has been an important pilot project for MAN PrimeServ that ultimately proceeded smoothly despite the restrictions imposed by the Covid-19 pandemic. Notably, we also successfully delivered the SCR systems pre-equipped with honeycombs in order to maintain the tight schedule. Besides some minor, technical adjustments post-installation, we easily reached the required exhaust-gas temperatures for SCR operation and regeneration of the honeycombs in testing. We still need to determine the exact urea consumption required to achieve the necessary NOx reduction, but, fortunately, the engines have been more recently equipped with new MAN turbochargers such that safe operation of the SCR systems is guaranteed.”

Siebert added: “Increasingly, we are receiving requests from cruise and ferry companies that want to improve their green credentials and who desire to become sustainable without the need for mandated industry legislation.”

The cruise ship is chartered by PHOENIX Reisen GmbH Bonn (Germany) and managed by BSM Cruise Services. The formal handover of the Amadea to PHOENIX Reisen took place in mid-January 2022 after classification society acceptance.