Development of Ultra-Steam Turbine (UST) in High-pressure/High-temperature Reheat Steam Turbine Plant for LNG Carriers

Abstract

Since the steam turbine plant have flexibility of fuel selection (oil only, gas only and dual), most propulsion plants for Liquid Natural Gas Carriers (LNGC) have been the steam turbine plant. However, the rising prices of fuel and shortage of the crew for the steam turbine plant, the movement to investigate higher efficiency propulsion plant has gotten active. Actually, a lot of LNGCs for European owners have adopted dual fuel diesel engine (DFE) with electric propulsion motor, and many large size LNGCs (200, 000 m3) built in Korean shipyard have adopted diesel engine with re-liquefaction plant (DRL) recently. Under such a situation, we propose new high efficiency plant; UST (Ultra Steam Turbine Plant) that has advantages of conventional steam turbines (high reliability, safety, low maintenance cost and easy operation) for the restitution of steam turbine plant, the recovery of the share and the exploitation of the new market. In this paper, we introduce the outline of the UST plant, and present the features and key technology of reheat turbine that is one of main components of UST plant.