A review on the use of gas and steam turbine combined cycles as prime movers for large ships, Part I: Background and design

The aim of the present paper is to review the prospects of using combined cycles as prime movers for large ships, like, container ships, tankers and bulk carriers. The paper is divided into three parts of which this paper constitutes Part II. In Part I, the environmental and human health concerns of international shipping were outlined.

The regulatory framework relevant for shipping and the design of combined cycles were discussed. Here, previous work and experience are reviewed, and an overview of the implications of introducing combined cycles as prime movers is included. In Part III, marine fuels are discussed and the pollutant emissions of gas turbines are compared with those of two-stroke, slow-speed diesel engines.In the past, combined cycles of COGAS and COGES configurations have been considered for ship propulsion.

Another application where gas turbine-based systems have been considered as prime movers is for LNG ships, which are traditionally powered by steam turbines with gas-burning boilers. Previous experience for a cruiser shows that combined cycles weigh less and require a smaller volume than diesel engines, resulting in increased passenger capacity and/or voyage performance.

Diesel engines respond faster to a load change than combined cycles. Provided parts within the steam cycle are warm, the start-up times of combined cycles and diesel engines are similar.