Energy and exergy analyses of hydrogen production by coal gasification

In this study, we examine an integrated coal based gasification system developed for hydrogen production and power generation. The proposed plant consists of air separation unit, gasification unit, gas cooling and cleaning unit, pressure swing absorption (PSA) for hydrogen production, high temperature electrolyzer for hydrogen production, Brayton cycle, steam Rankine cycle and organic Rankine cycle (ORC) system for power generation. We investigate this system through energy and exergy analyses for hydrogen production. Six coal types, such as Beypazari, Tuncbilek, Can, Yatagan, Elbistan and Soma are considered in this study and energy and exergy efficiencies of these coals are compared to each other for assessment and evaluation. The Aspen Plus and Engineering Equation Solver (EES) software packages are used for system simulation and system analyses. The results show that the overall energy and exergy efficiencies of the entire system become 41% and 36.5%, respectively. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.