1,721,054 research outputs found
Methodology of exergy-based economic analysis incorporating safety investment cost for comparative evaluation in process plant design
No full textThis study proposes a new methodology of exergy-based economic analysis incorporating safety investment cost (SIC) for the comparative evaluation of process design alternatives for plants in terms of efficiency and economics while considering safety. Exergy-based economic analysis is employed to synthetically evaluate the design factors within the same framework. The SIC is estimated as the cost required to ensure the safety of the design by reducing accident risks to a level that is 'as low as reasonably practicable' (ALARP), which presents a rational approach to converting the risks associated with design alternatives into monetary values for economic analysis. The proposed method is applied to select the optimal working fluid in the Rankine cycle used in the recovery of both waste heat from a gas turbine and cold energy from liquefied natural gas (LNG) of the regasification process. The Rankine cycle, using ammonia, propane, and carbon dioxide as the working fluid, produces electric power of 11.7 MW, 8.9 MW, and 7.4 MW with specific exergy costs of 45.0 KJ, 61.9 /GJ, respectively. Ammonia can be selected as the best alternative. The results are limited to quantitative risk assessment that does not consider domino effect and environmental damage. (C) 2019 Elsevier Ltd. All rights reserved.
Pressurized cryogenic air energy storage for efficiency improvement of liquid air energy storage
No full textWith the development of renewable energy sources, large-scale energy storage has been studied such as advanced compressed air energy storage (CAES) and liquid air energy storage (LAES). In this study, a novel pressurized cryogenic air energy storage system (PCAES) is proposed and analyzed. The conventional LAES system produces and stores the liquid air at the ambient pressure. The system achieves 40% to 60% of round-trip efficiency depending on the use of liquid turbo-expander. Meanwhile, this proposed system stores the air near the critical point by expanding it at 40 bar using turbo-expander. This significantly reduces the energy input in comparison to liquefying the air. This system is modeled with commercial process simulation software, Aspen HYSYS v.8.8. It significantly improves the round-trip efficiency of the conventional stand-alone liquid air energy storage system. However, this system requires pressurized tanks for the supercritical air storage. The economic evaluation for energy storage cost should be analyzed depending on variables such as storage time, storage to generation power ratio, and size of the power system. The above-ground CAES, LAES, and the proposed system would be the competitive system without geological limitations and are potentially applicable for the various energy demand-supply environments and the markets
Safety and Control Standards for Hydrogen Ships: Cargo Handling and Fuel Gas Supply Systems
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Combining dynamic process simulation and Monte Carlo simulation for risk-based design
No full textIn this study, a new method combining Dynamic Process Simulation (DPS) and Monte Carlo Simulation (MCS) is proposed for risk-based design. Operating conditions (pressure and temperature) are generally estimated by process simulation without considering realistic system behavior such as equipment failure and repair events. Although equipment failure and subsequent repair affect the pressure and temperature profile, it is difficult to apply these features directly in the process simulation because of the randomness of failure. Thus, in this study, to predict practical operation conditions, MCS is combined with DPS. MCS is employed to predict when and where failure of equipment and its subsequent repair occur and to describe a realistic lifetime scenario of the system operation. Combining MCS with DPS enables a description of realistic operating conditions and excessive conditions in accordance with failure and repair events. The excessive conditions provide risk-based information for use in design. © 2014 Taylor & Francis Group, London
Design and Evaluation of an LNG-LH2 Hybrid Propulsion System for an LNG Carrier Complying with Regulations on Emissions
No full textA Study of Deterination of the Design Accidental Fire Load based on the Quantitative Fire Risk Assessent with the Treatent of Uncertainty
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