A Comparison of Organic and Steam Rankine Cycle Power Systems for Waste Heat Recovery on Large Ships

Abstract

This paper presents a comparison of the conventional dual pressure steam Rankine cycle process and the organic Rankine cycle process for marine engine waste heat recovery. The comparison was based on a container vessel, and results are presented for a high-sulfur (3 wt %) and low-sulfur (0.5 wt %) fuel case. The processes were compared based on their off-design performance for diesel engine loads in the range between 25% and 100%. The fluids considered in the organic Rankine cycle process were MM(hexamethyldisiloxane), toluene, n-pentane, i-pentane and c-pentane. The results of the comparison indicate that the net power output of the steam Rankine cycle process is higher at high engine loads, while the performance of the organic Rankine cycle units is higher at lower loads. Preliminary turbine design considerations suggest that higher turbine efficiencies can be obtained for the ORC unit turbines compared to the steam turbines. When the efficiency of the c-pentane turbine was allowed to be 10% points larger than the steam turbine efficiency, the organic Rankine cycle unit reaches higher net power outputs than the steam Rankine cycle unit at all engine loads for the low-sulfur fuel case. The net power production from the waste heat recovery units is generally higher for the low-sulfur fuel case. The steam Rankine cycle unit produces 18% more power at design compared to the high-sulfur fuel case, while the organic Rankine cycle unit using MM produces 33% more power.

Thermodynamic, Environmental and Economic Simulation of an Organic Rankine Cycle (ORC) for Waste Heat Recovery: Terceira Island Case Study

“…Also, research has shown that ORC has clearly a better performance when compared to Steam Rankine Cycle (SRC) (using water as the working fluid). It enables internal heat recovery, higher turbine efficiencies, and net power outputs [26]. R245fa was 352 chosen as a working fluid because, when compared with refrigerants such as R11, R114 or R141b, it has zero Ozone Depletion Potential, lower global warming potential, low toxicity, and it is non-flammable [27].…”

“…To assess the sustainability of this investment Eq. 20- (26) were used ( Table 3). For the risk analysis, the Monte Carlo simulation of palisade @risk tool was used.…”

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.…”

Systematic Optimization-Based Integrated Chemical Product–Process Design Framework

“…However, given the high sensitivity between the fluid properties and the cycle process operating conditions and performance, this is a challenging tasks with existing heuristic approaches [38]. Recent literature point at the need for use of CAMD techniques for finding novel refrigerants [25].…”