Thermo‐economic analysis and optimization of a combined Organic Rankine Cycle ( ORC ) system with LNG cold energy and waste heat recovery of dual‐fuel marine engine

Abstract

A combined Organic Rankine Cycle (ORC) system with liquefied nature gas (LNG) cold energy and dual-fuel (DF) marine engine waste heat utilization was proposed. Engine exhaust gas and engine jacket cooling water were adopted as parallel heat sources. Thermo-economic analyses of the proposed system with 32 working fluids combinations were performed. Two objective functions covering thermal efficiencies and economic index were employed for performance evaluation. Afterward, the effects of operation pressure on the objective functions were investigated. Finally, the optimal conditions were obtained from the Pareto front with the Non-dominated Sorting Genetic Algorithm-II (NSGA-II) method. The results show that the proposed ORC system has better energy recovery performances than the parallel ORC system. R1150-R600a-R290, R1150-R601a-R600a, and R170-R601-R290 are determined as the three most promising working fluids combinations. Under optimized conditions, the output power range is 199.97 to 218.51 kW, the energy efficiency range is 13.64% to 15.62%, and the exergy efficiency range is 25.29% to 27.3%. The payback period ranges from 8.36 to 8.74 years. The working fluids selection helps to reduce the exergy destruction of intermediate heat exchanger, which could be up to 30.59%.

Multi‐objective optimization of a novel biomass‐based multigeneration system consisting of liquid natural gas open cycle and proton exchange membrane electrolyzer

“…The chemical engineering plant cost index (CEPCI), which adjusts process plant construction costs from one period to another, for 2020 is 596.2. 39 The purchased equipment cost of each component is listed in Table 3.…”

Developed hydrogen liquefaction process using liquefied natural gas cold energy: Design, energy optimization, and techno‐economic feasibility

“…[30][31][32] Furthermore, process optimization is conducted by connecting the simulation results of Aspen HYSYS to GA in MATLAB to minimize the SEC. Multiparameter optimization can contribute to finding optimal results because the hydrogen liquefaction process consists of many input variables and nonlinear constraints 33,34 The results are then evaluated from both thermodynamic and technoeconomic perspectives for feasibility. The novelty of this work is summarized as follows:…”

Proposing a New Route to Solve Marine Debris Pollution Issues: Low-Temperature Eco-friendly Pulverization System by Utilizing LNG Cold Energy

“…According to Tian et al, given the dual-fuel engine ship, about 860 kJ/kg of cold heat is wasted when LNG is vaporized and overheated 43 . Therefore, it is advantageous to improve and/or develop a system to maximize the usage of excessive LCE.…”