The electrical energy produced is utilized in supplying power to all the consumers and the excess power is directed to the Shaft motors installed on the propeller shaft for assisting in main propulsion. The nominal electrical power produced by this system is 8.5 Mega Watts.
The main components of the system are –
Main engine – produces exhaust gas from combustion.
Economiser – Steam production using heat energy from exhaust gases. Low pressure and High pressure drums – storage of pressure energy from steam.
LP and HP Steam turbines – converts pressure energy from LP and HP drums to mechanical energy in running up the Turbine generator.
Gas turbine - converts pressure energy from the by-passed exhaust gas to mechanical energy and boosts up the Turbine generator.
Shaft motors – assist in main engine propulsion.
The process of energy transformation is given below:
Waste heat energy from exhaust gas ------via Economiser-----> Pressure energy(Superheated steam)stored in LP and HP drums ------via Steam turbine--------> Mechanical energy ------via TG Alternator---------> Electrical energy
A part of the exhaust gas from the Main engine exhaust receiver is bypassed to the gas turbine which boosts up the Turbine generator.
This system has the following advantages over other shipboard power production plants:
- Maximum utilization of Waste heat energy
- Reduced fuel consumption
- Reduced maintenance and Man hours
All of this leading to a more economical ship.
An article by: Nirmal and Arunmozhi
Courtesy: Elly Maersk
