Design of Storage Equipment for Unstable Chemicals Using Sensitivity-Based Methods

The storage of thermally unstable chemicals poses significant risks, including runaway reactions that can lead to severe accidents. Developing inherently safe and cost-effective design strategies for storage vessels is essential for improving chemical plant safety and reliability. This study presents an advanced methodology based on an expanded Frank-Kamenetskii theory of self-heating (FKT), incorporating finite activation energy effects and mass consumption to address key limitations of the original framework. The approach integrates parametric sensitivity analysis to generate stability and performance diagrams, providing insights into safe and runaway operating regimes and optimizing storage policies. The methodology is validated using hydroxylamine-based systems, demonstrating its applicability to real-world cases. Experimental results show that a 30% w/w aqueous hydroxylamine solution can be stored at 35 °C in a vessel over twice the size required for a 50% solution. Sensitivity analyses reveal that the design outcomes are most influenced by the dimensionless heat of reaction and reaction order, with minimal dependence on the Lewis number. Refined FKT versions support the design of safer, larger vessels with characteristic sizes reduced by 10% compared to the original framework. However, increased refinement adds complexity. Therefore, applying different FKT versions at various design stages is recommended to balance accuracy and complexity.