Application of Safety by Design Methodology in Evaluating Process Safety for a Duff Reaction Using Predictive Process Simulators

摘要

This work presents a Safety by Design (SbD)-driven approach to the evaluation of process safety and reaction modeling that was effective in obtaining enhanced process knowledge and defining a design space for chemical reaction hazards. The SbD approach is presented for a case study involving the process development of the Duff reaction of phenol derivative with hexamine as a formylation reagent in polyphosphoric acid as a solvent. The starting materials were characterized by a thermal scan, and reactions were explored by different calorimetric methods. The enthalpies of physical and chemical rates of starting materials were determined using an isoperibol reaction calorimeter. The adiabatic calorimeter data provided experimental knowledge of possible side and decomposition reactions. The parameters of these reactions were estimated, which is of significant importance for scaling up the processes. The engineering aspects of the process were explored by process modeling using computer process simulators. On the basis of the proposed reaction mechanism and the combination of the heat and mass transfer and the reaction's thermodynamics and kinetics, the safety risk was described by modeling of the process space through safety parameters (e.g., adiabatic time to maximum rate, maximum temperature, and pressure rise) under practical operating conditions of a plant and its equipment limitations (reactor batch size, time of reagent addition, and/or initial jacket temperature).