(197a) Inherent Safety Risk Assessment of Alternative Blue Ammonia-Urea Supply Chains

The growth of the petrochemical industry and the development of massive ammonia and urea supply chains led to increased synthesis gas and energy demands. Ammonia is produced through either steam methane reforming (SMR) or auto-thermal reforming (ATR) processes, and around 80% of produced ammonia is used as a feedstock to produce fertilizers. Moreover, Ammonia is also a potentially viable cleaner energy carrier as it is cheaper to store and transport than pure hydrogen. Urea is the most utilized nitrogen fertilizer which makes it play an essential role in ensuring food security around the world. Several technologies are available for the production of ammonia and urea. When comparing alternative pathways, conducting a techno-economic analysis is crucial. Additionally, safety analysis must be given equal consideration in the decision-making process when selecting the best pathway. The challenge is in the safety assessment of the process during the design’s early stages. Urea and ammonia supply chains are prone to accidents. The high percentage of accidents with no known cause makes the application of inherent safety tools even more necessary.

This work presents a comparative study of the different pathways for blue ammonia-urea production, using the Inherently Safer Design Tool (i-SDT) as the risk assessment tool. The tool allows the user to evaluate the safety of the process in the initial stages of plant design using data obtained from historical accident databases. The safety parameters considered were flammability, explosiveness, reactivity, and toxicity. A cluster safety parameter score represents the relative safety score for each process unit, section, and considered pathway. The pathways consider alternatives for syngas production (syngas production, purification, and urea synthesis technologies). The work aims to provide insights into the tradeoff between the competing objectives of enhanced operations and reduced environmental impacts considering inherently safe design strategies. The study showed that steam reforming pathways outperformed auto-thermal reforming in terms of environmental and economic performance. However, the pathways that consist of ATR were found to have relatively lower flammability Safety parameter scores than those with SMR, making pathways with an ATR section appear less susceptible to accidents than their counterparts with an SMR section.