3Steam Turbine Powered Ships There are still some steam powered vessels such as ULCC ( Ultra Large Crude Carrier )Steam turbines can provide the high power that is necessary to propel the ship.However, most ships nowadays use the more economical diesel burning engines.
4Steam TheoryBoilersAlthough boilers may not often be found for ship propulsion there is almost always one boiler on board a ship. Boilers are used for things such as heating cargo, fuel, and accommodations.Some ships also use boilers for auxiliary power. Such as deck winches and pumps, because if they used electrical machines it would be dangerous if the cargo was oil.
5Steam Theory Babcock Marine Water Tube Boiler Water enters the boiler, preheated at the top. The hot water circulates through the tubes down to where it is hot. The water heats up and flows back to the steam drum where the steam collects.The water that doesn’t turn to steam, goes back into the system and the process starts again.
6The control system controls the temperature of the steam drum to determine if it should turn the burner on or offThe water that enters the boiler, is called feed water. It has chemicals in it neutralize minerals in the water, which could block or rust the pipes.
7Water tube boilers pressures = 7 to 250 bar Saturated steam, 100 ocSuperheated dry steam oc.In water tube boilers can produce 1.5 to steam/hr
8Different types of boiler Fire Tube BoilerUsually used for ships heatingAuxiliary BoilerOn larger vessel the auxiliary boiler auxiliary boiler uses the main engine's flue gases to heat the water
9Steam TurbineThe turbine is connected to a reduction gear, which drives a propeller
10The impulse turbine contains several turbine rotors, pictured to the right. In front of these rotors are nozzles.The nozzle ejects steam onto one blade of the rotor and makes it turn
11One set of turbine rotor and stationary nozzles is called a stage One set of turbine rotor and stationary nozzles is called a stage. The steam travels through many stages.The steam proceeds through one stage, then collects and proceeds to the second stage and so on.Every time, the steam proceeds to a bigger rotor turbine, until the most of it's energy has been used on the rotors of the turbine.The steam that is left is sucked by vacuum, to the condenser where it is cooled to form feed water, ready to feed the boiler once again.