Comparative optimization study and 4E analysis of hybrid hydrogen production systems based on PEM, and VCl methods utilizing steel industry waste heat

Abstract

Global warming and climate change are the challenges caused mainly by greenhouse gases. To tackle the issue, limiting the emission of these gases would be essential. This study conducted a technical and economic evaluation of hydrogen production from waste heat using a proton exchange membrane electrolyzer and a vanadium chloride thermochemical cycle. These systems are integrated separately and in combination with Rankine steam and organic cycles to form three different hybrid systems. These three systems operate at the same input energy through factory waste heat at 810 °C. Each system was separately optimized—employing a genetic algorithm and artificial neural network—to find the best performance points from economics, environment, energy, and exergy viewpoints. Then, the performance of the three systems is examined and compared. The results indicate that the vanadium chloride system outperforms the proton exchange membrane and proton exchange membrane-vanadium chloride in terms of hydrogen production and efficiency. vanadium chloride cycle, as the best scenario, showed the capacity to produce 203.018 tons of hydrogen annually along with 18,504 MWh of energy per year, with energy and exergy efficiencies of 43.71 % and 56.69 %, respectively. Economic analysis results indicate that the payback period for proton exchange membrane, vanadium chloride, and proton exchange membrane-vanadium chloride are 9.829, 4.228, and 6.383 years, respectively. Furthermore, the CO2 emissions reduction for the three scenarios proton exchange membrane, vanadium chloride, and proton exchange membrane-vanadium chloride is 8378, 11201, and 10,002 tons per year, respectively.