Retrofit Degassing Installations Increase Efficiency Of Two Dredgers

摘要

The presence of gas in dredged mixtures attacks the efficiency of the dredge pump and therefore the entire dredging process. Gas is usually present in layers of silt, which means contractors engaged in maintenance dredging operations are among those most likely to be affected by the problem. One such company is Dragages Ports, the French government owned contractor whose primary activity is maintaining safe depths for navigation in the country's major ports and fairways.rnTwo of Dragages Ports' vessels, the 8,500m~3 capacity trailing suction hopper dredger Samuel de Champlain and the 5,000m~3 capacity trailer Daniel Laval were both suffering from gas problems. Damen Dredging Equipment (DDE) was brought in to design and install retrofit degassing systems for both vessels. Samuel de Champlain was to be equipped with a suction pipe mounted degassing system designed for an in situ gas content of 4% whilst for thernsmaller Daniel Laval the target was 3%. As the degassing system runs on the existing jetwater pumps, the situation called for trouble shooting and redesigning the existing jetwater systems.