Exergetic Evaluation of a High-Pressure Hydrogen Production System

This study presents exergetic assessment of a high-pressure hydrogen production system (HPS). The system considered in this study includes a high-pressure proton exchange membrane (PEM) electrolyzer, two heat exchangers, a motor pump system, a circulation pump, and a hot water tank. In order to perform the main objective of this study, the following important parameters are taken into consideration: (1) the operating pressure (ranging from 1 to 200 bar), (2) the operating temperature (ranging from 70 to 80 °C), (3) dead-state temperature (assumed to be 25 °C), (4) the energy efficiency of the PEM electrolyzer (ranging from 0.5 to 1), (5) the pump efficiency (assumed to be 0.8), (6) mass flow rate of hydrogen from PEM electrolyzer (3 kg per hour), and (7) mass flow rate of pure water supplied to the PEM electrolysis (27 per hour). Considering all these parameters, exergy analysis is performed for the HPS. The results show that exergy efficiency of HPS increases with the rise of the operating pressure and temperature. It thus requires a higher amount of energy input. In this regard, there is a strong need to optimize the process. © Springer International Publishing Switzerland 2014

Feasibility Study for Production of Hydrogen from Agricultural Solid Residue with Reference to Malaysia Using ASPEN Plus Simulation

© 2018, Springer Nature B.V. A technical and feasibility assessment has been conducted for gasification of solid agricultural residue to produce hydrogen in Malaysia. The availability and current technologies for using biomass has been reviewed. Flow sheet for the process has been conceptualized and the material and energy balances for the process along with a plant-wide simulation using the software ASPEN Plus have been undertaken. Powdered Nickle Oxide (NIO-B) has been proposed as catalyst to give approximately 95% purity. Furthermore, the economic analyses worst, base and best financial scenarios have been done and in all cases, the rates of investment (ROI) analysis have been undertaken. From the economic analysis, it has been observed that the total estimated cost for a base scenario, the plant would be USD $52,413,276 for an annual feed rate of 241,938,900 kg. Based on current market of hydrogen and carbon dioxide the payback period for the base case plant would be 1.51 years with the total annual profit of USD$11,045,497.79, which corresponds to a ROI of 12.43%