Chemical Engineering
A. Graeeli; M. Rahimi-Esbo; V. Kord Firouzjaee; M. Sedighi; M. Rezaee Firouzjaee
Abstract
Considering the escalating significance of hydrogen production as a high-energy-density fuel, coupled with the challenges associated with its transportation and storage, the necessity to generate hydrogen at the point of consumption has become more pronounced than ever before. Thus, this research endeavors ...
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Considering the escalating significance of hydrogen production as a high-energy-density fuel, coupled with the challenges associated with its transportation and storage, the necessity to generate hydrogen at the point of consumption has become more pronounced than ever before. Thus, this research endeavors to comprehensively investigate various hydrogen production processes and elucidate the merits and drawbacks of each technique. Additionally, the catalysts employed in these processes were examined, ultimately leading to the selection of methanol steam reforming using a Cu/ZnO/Al2O3 catalyst within a fixed bed reactor for hydrogen production. Subsequently, the process underwent initial simulation utilizing Aspen Plus software, enabling a close-to-reality assessment of the simulation's challenges. Following the validation of the simulation results, a comparative analysis was conducted between a reactor operating at a specified temperature (T=220℃) and a co-current reactor. Each reactor possessed distinct advantages and disadvantages. Through this comparison, it was observed that, in order to achieve the same conversion, the length of the co-current reactor could be reduced by 5.7 cm compared to the specified temperature reactor. Consequently, the construction cost was reduced; however, this modification resulted in an increased production of carbon monoxide, necessitating further investigation.
Energy
N. Hedayati Goodarzi; M. Rahimi-Esbo
Abstract
Steam reformers are typically utilized in hydrogen production industry, demanding pressure vessels within methanol reformer systems operating at temperatures between 250-350°C to ensure cost-effectiveness. This characteristic makes them a superior choice for fuel cell systems. However, challenges ...
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Steam reformers are typically utilized in hydrogen production industry, demanding pressure vessels within methanol reformer systems operating at temperatures between 250-350°C to ensure cost-effectiveness. This characteristic makes them a superior choice for fuel cell systems. However, challenges arise in enhancing hydrogen gas production efficiency while minimizing carbon monoxide emissions. Computational Fluid Dynamics (CFD) has proven effective in addressing these challenges by simulating fluid behavior. This study delves into product production, reactant consumption using CFD, and investigates changes in physical parameters of methanol reformers to optimize their performance. The research involves 140 numerical simulations that examine the relationship between feeds (steam-to-carbon) and various temperatures, aiming to understand the concurrent effect of physical parameters. The results demonstrate that increasing temperature has a more significant impact on hydrogen production compared to increasing the feed ratio. This effect is particularly notable at lower fuel ratios. For example, at a feed ratio of 1, a temperature increase of 11.4°C leads to a substantial 5.4% rise in hydrogen production. However, at a higher feed ratio (1.98), the increase in hydrogen production is only 1.9% with the same temperature increase.
