Assessment of inherently safer technologies for hydrogen production

The spread of hydrogen as an energy carrier will lead to a global increase of its production, requiring the development of more reliable and efficient production processes. Several research efforts are currently devoted to hydrogen production via steam reforming of natural gas. New catalytic reactors and separation equipment are considered for industrial implementation. These technologies are at an early stage of development and safety assessment is usually based on inherent safety approaches, addressed to the selection of the safer design solutions. However, the state of the art of the methodologies for the identification and the assessment of inherently safer processes are usually based on the assessment of a discrete set of indexes or key words, that may not be adequate to represent the actual hazards that are present in hydrogen processing and storage. A novel consequence-based method for the identification and the assessment of inherently safer processes in plant design was developed and applied to the assessment of alternative steam reforming processes. A low detail of information is required to implement the methodology: process flow diagrams, equipment description, process conditions and inventories are sufficient for the evaluation of unit safety indexes. A synthetic process inherent safety index is evaluated starting from these data, in order to allow a quantitative comparison between the different processes. In the present study, a commercial tool was used for consequence evaluation of hydrogen release scenarios, but, clearly enough, the development of more reliable tools for consequence modelling, specifically dedicated to the consequence assessment of hydrogen releases, would be crucial to enhance the reliability of the method.