Methodology and software for assessing reactivity ratings of chemical systems

To resolve various problems in creating a process, or conducting stability analysis, and/or hazard assessments, one needs t o know the reactivity of a chemical system. The National Fire Protection Association (NFPA) requires use of a reactivity rating number to describe such reactivity potentials as thermal stability, interaction with water, and gas generation. For assessing thermal stability of a substance, NFPA has recently accepted a new quantitative approach based on the idea of “Instantaneous Power Density.” Though it has many advantages compared to the largely qualitative previous approach, the new method has one serious draw‐back—it doesn't take into account the peculiarities of such complex cases as self‐accelerating or multi‐stage reactions. This, in turn, can lead to a less‐than‐safe, or unsafe, design. In this paper, we propose a method to generalize the concept of instantaneous power density by considering the maximal power density as the quantitative measure of the reactivity, allowing one to take proper account of kinetic complexity. We also briefly discuss the ReRank software which was developed to assess reactivity ratings in general, and specifically, to calculate reactivity rating numbers.