Inherent safety assessment of alternative processes for hydrogen production

The topic of the climate change has become a crucial problem that all the Planet has to face. Indeed, the GHG emissions are one of the main factors causing climate change, that can lead to the damage of the biodiversity. Therefore, nowadays the industry needs to find alternatives to fossil fuels for the production and supply of energy and the use of hydrogen as an energy vector is currently under investigation. In this study, five alternative processes for the production of hydrogen were analyzed from the point of view of inherent safety. The production of hydrogen from methane feedstock have been considered in the first three alternatives. In the last two options the production of hydrogen from water by the use of fuel cells have been investigated. Firstly, methodologies addressing both sustainability assessment and inherent safety assessment in early design were examined. Secondly, each of the five processes considered was studied, and a preliminary process design was carried out. The mass balances of all the alternative process schemes were calculated and the flowrates, the compositions, the operative temperature and the pressures of each equipment were calculated. A method for the quantitative assessment of inherent safety has been applied to obtain inherent safety key performance indicators (KPIs). In order to calculate the KPIs, potential damage distances have been calculated for each equipment using the Aloha software. From the analysis it is clear how the first alternative appears to be the worst from the point of view of the safety. Moreover, when credit factors are considered, it can be noticed how the three process alternatives in which hydrogen is produced from methane present a higher inherent hazard index due to the higher amount of auxiliary units present.