Waste Heat Recovery from Marine Gas Turbines and Diesel Engines

Abstract

Abstract:The paper presents the main results of a research project directed to the development of mathematical models for the design and simulation of combined Gas Turbine-Steam or Diesel-Steam plants for marine applications. The goal is to increase the energy conversion efficiency of both gas turbines and diesel engines, adopted in ship propulsion systems, by recovering part of the thermal energy contained in the exhaust gases through Waste Heat Recovery (WHR) dedicated installations. The developed models are used to identify the best configuration of the combined plants in order to optimize, for the different applications, the steam plant layout and the performance of WHR plant components. This research activity has allowed to obtain significant improvements in terms of energy conversion efficiency, but also on other important issues: dimensions and weights of the installations, ship load capacity, environmental compatibility, investment and operating costs. In particular, the main results of the present study can be summarized as follows: (a) the quantitative assessment of the advantages (and limits) deriving by the application of a Combined Gas And Steam (COGAS) propulsion system to a large container ship, in substitution of the traditional two-stroke diesel engine; (b) the proposal of optimized WHR propulsion and power systems for an oil tanker, for which a quantitative evaluation is given of the attainable advantages, in terms of fuel consumption and emissions reduction, in comparison with more traditional solutions.

Ideal Point Design and Operation of CO2-Based Transcritical Rankine Cycle (CTRC) System Based on High Utilization of Engine’s Waste Heats

“…While, engine coolant is a relative low grade waste heat, whose temperature is below 100 • C, but still significant due to the comparative amount of waste heat [2]. Using a thermodynamic cycle to generate extra power is a high-efficiency way among the technologies of E-WHR, mainly including single-loop organic Rankine cycle (ORC) [3,4], dual-loop ORC [5,6], steam Rankine cycle [7,8], CO 2 -based transcritical Rankine cycle (CTRC). Moreover, thermodynamic cycle is a feasible scheme to make a combined recovery of exhaust gas and engine coolant.…”

Simulation Techniques for Design and Control of a Waste Heat Recovery System in Marine Natural Gas Propulsion Applications

“…In the present case study, the computation of the feedback gain for the linear time-invariant, sketched in Figure 7, system is evaluated via LMI solution. The regulator can be represented as: u = K P e n + K I t 0 e n (ζ)dζ (13) where the scalar parameters K P and K I are suitably chosen in such a way to ensure closed-loop stability and e n = n d − x 2 is the shaft speed error. Thus, the closed-loop dynamics is:…”

“…For the considered case study, simulation results confirm the validity of the developed approach, aimed to test the correct design of the whole system in proper working dynamic conditions. of the vessel [10][11][12][13]. The simultaneous use of gas-fueled engines together with Waste Heat Recovery (WHR) systems can strongly improve the ship energy efficiency, with significant fuel savings and emissions reduction [14][15][16][17][18][19].…”

Investigation of In-Cylinder Steam Injection in a Turbocharged Diesel Engine for Waste Heat Recovery and NOx Emission Control

“…As fuel consumption and emissions regulations are becoming more stringent, energy saving and emissions reduction have become the impetus for development and the goal of modern internal combustion engines [1,2]. Various technologies have been proposed to achieve this goal, such as turbocompounding [3], Miller cycle [4], exhaust gas recirculation (EGR) [5], waste heat recovery [6,7], use of alternative fuel [8], and so on. Water injection, another useful technology to improve engine performance and reduce emissions, has also been widely researched.…”