Exhaust system with water injection for the 'La Suisse' paddle steamer
CGN, established in Lausanne Switzerland, is the owner of the largest fleet of ‘Belle Epoque’ vessels in the world from the point of view of total passenger capacity. Their ships have plied the waters of Lake Geneva in Switzerland for more than 130 years. They are used for, among other things, romantic cruises (on paddle steamers) between France and Switzerland. CGN has its own yard where maintenance work can be carried out on the fleet.
At the end of 2007, Discom B.V. was approached by CGN with a request to research the possibility of fitting an exhaust system with water injection to the two 200 kVA generator sets on board the ‘La Suisse’ paddle steamer. A number of ships with generator sets had already been fitted with conventional (that is uncooled) exhaust systems, as a result of which the insulated pipes took up a relatively large amount of space. During preparations for the renovation of the ‘La Suisse’ (the oldest paddle steamer in the CGN fleet, having been constructed in 1910) it transpired that even longer pipes would be needed, implying serious integration or counterpressure problems. The application of water injection in the exhaust gas means a smaller pipe size can be chosen and also that the pipe no longer needs to be insulated.
An additional requirement was that the noise levels on board the ship have to be as low as possible in connection with the high demands as regards comfort. Discom B.V. created a design following a visit on board the ‘La Suisse’ and similar ships and a subsequent study of the drawings and engine and pump data. The design comprises an exhaust silencer for each generator, followed by a water injection and water separator system. All these components are then assembled in the generator room. Special, compact follow-up silencers were also installed in the ship's funnel. In addition, the pipes now no longer have to be insulated because the temperature of the exhaust gas does not exceed 60 °C. The noise of the diesel engines is can now no longer be heard on the deck, not even if the engines are operating at full load, and this is a huge difference when compared to other similar vessels in the fleet. The counterpressure in the exhaust system also appears to be under the maximum permissible limit value.
CGN is so pleased with the result that it has since asked Discom B.V. to draw up a proposal for a second ship.