It is well known that in early design process hazards, as well as hazards associated to lay-out issues, may be effectively reduced by proper design solutions. In this stage of process design, a simplified and straightforward approach to the quantitative assessment of inherent safety and escalation hazard may be a suitable tool to provide guidelines for proper design choices. Nevertheless, existing methods for inherent safety assessment are mainly aimed to the general assessment of chemical reaction processes, not focusing on escalation hazard. Moreover, most of the available methods for inherent safety assessment are based on somehow arbitrary hazard indexes, derived from expert judgment. In the present study a specific methodology was developed for the comparison of expected safety performances among different process alternatives, focusing on escalation hazard analysis. The input for the application of the method are the same needed for the definition of a quantitative process flow diagram: (i) definition of substances and operative conditions in each unit of the process; (ii) quantification of flows in process lines and piping; (iii) general technical specifications of the equipment units and (iv) evaluation of inventories in the equipment units of each process alternative. The methodology allows the calculation of key performance indicators (KPIs). The KPIs allow the quantification of both potential and inherent hazards, also related to escalation hazard, addressing the identification of the less hazardous among possible process alternatives. In order to test the methodology, some case studies were defined, focusing on hydrogen storage technologies. The commercial and available process schemes were compared with innovative ones, also addressing escalation hazard assessment. Preliminary indications on the inherently safer technologies were obtained for hydrogen storage technologies. Critical elements and safety distances necessary to prevent escalation effects were identified.
The assessment of inherent safety and escalation hazard in the early stage design of hydrogen storage plants
TUGNOLI, ALESSANDRO;COZZANI, VALERIO
2008
Abstract
It is well known that in early design process hazards, as well as hazards associated to lay-out issues, may be effectively reduced by proper design solutions. In this stage of process design, a simplified and straightforward approach to the quantitative assessment of inherent safety and escalation hazard may be a suitable tool to provide guidelines for proper design choices. Nevertheless, existing methods for inherent safety assessment are mainly aimed to the general assessment of chemical reaction processes, not focusing on escalation hazard. Moreover, most of the available methods for inherent safety assessment are based on somehow arbitrary hazard indexes, derived from expert judgment. In the present study a specific methodology was developed for the comparison of expected safety performances among different process alternatives, focusing on escalation hazard analysis. The input for the application of the method are the same needed for the definition of a quantitative process flow diagram: (i) definition of substances and operative conditions in each unit of the process; (ii) quantification of flows in process lines and piping; (iii) general technical specifications of the equipment units and (iv) evaluation of inventories in the equipment units of each process alternative. The methodology allows the calculation of key performance indicators (KPIs). The KPIs allow the quantification of both potential and inherent hazards, also related to escalation hazard, addressing the identification of the less hazardous among possible process alternatives. In order to test the methodology, some case studies were defined, focusing on hydrogen storage technologies. The commercial and available process schemes were compared with innovative ones, also addressing escalation hazard assessment. Preliminary indications on the inherently safer technologies were obtained for hydrogen storage technologies. Critical elements and safety distances necessary to prevent escalation effects were identified.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
