1DITEN, University of Genoa, Genoa, Italy

2DIME, University of Genoa, Genoa, Italy

Corresponding author:

Giovanni Benvenuto, DITEN, University of Genoa, Via Montallegro 1, 16145 Genoa, Italy。

Email: benvenuto@dinav。unige。it

2 Proc IMechE Part M: J Engineering for the Maritime Environment

WHR system’s modelling and simulation, for the devel- opment of control systems in stationary and dynamic situations。 Finally, a thermodynamic  analysis  (based on the energy and exergy efficiencies) is applied in Byung Chul and Young Min13 to a dual-loop heat recovery system comprising an upper trilateral steam cycle and a lower organic Rankine cycle。

In this work, starting from a thermo efficiency system (TES as called by its  manufacturer)  scheme7  proposed by MAN Diesel & Turbo, based on a dual-pressure heat recovery steam generator (HRSG), the authors evalu- ated possible alternative plant configurations in order to improve the amount of energy recovered。 To this aim, a comparison has been carried out between a WHR plant based on a typical dual-pressure steam system and an alternative solution defined by the  authors。

Both the above-mentioned plant layouts can adopt

Table 1。 Main ship dimensions。

Overall length 274。4 m

Length between perpendiculars 264。0 m

Breadth (moulded) 48。0 m

Depth (moulded) 23。2 m

Designed draught (moulded) 16。0 m

Scantling draught (moulded) 17。0 m

Table 2。 Electric power demand in normal seagoing for different ship load conditions。

Operating conditions Seagoing

Normal With tank heating Average Peak Average Peak

Electric load (kW) 785。0 856。6 1000 1098。5文献综述

either ST and gas turbine or simply ST for power generation。

The different WHR plant options have been mod- elled by means of simulation and applied to a specific propulsion system, consisting of a MAN  two-stroke DE (6S70ME-C8。2), selected as prime mover of a 158,000 DWT crude oil tanker (Suezmax), belonging to

Diesel generator

total power in service (kW) Diesel generator load factor (%)

900 900 1800 1800

87。2 95。2 55。5 61。0

the Premuda company。

All the considered WHR plant schemes have been optimized by varying the working parameters, namely, the design data of the various components, assuming the normal continuous rating (NCR) of the engine as the reference working condition for the optimization。 In this article, the performance of the optimized WHR plant layouts is evaluated by comparing them not only at the engine NCR load but also under off-design con- ditions, in the engine power range between 50% and 100% of the maximum continuous rating (MCR)。

Ship data and requirements

In Table 1, the main dimensions of the ship considered for this study are shown。

The propulsion engine of the ship,  mentioned before,   is   characterized   by   a   maximum   power of