Experimental sensitivity analysis of the runaway severity of Dicumyl peroxide decomposition using adiabatic calorimetry

The behavior of Dicumyl peroxide (DCP) under runaway conditions was studied using low and high phi factor (φ) calorimeters. Solutions of 20, 30 and 40%, by weight, of DCP in 2,2,4-trimethyl-1,3-pentanediol diisobutyrate and cumene were run at different phi factors experiments(1.8 > φ > 1.1). The results depicted that cumene reduces the severity of the runaway decomposition of DCP, while the phi factor of the experiments showed to have a high influence on the rise of temperature and pressure. Values up to 18 and 27 times higher, respectively, were obtained at same concentration when reducing the phi factor from 1.8 to 1.1. Temperatures and self-heating rates obtained at different phi factor experiments were scaled up to a phi factor equal to 1.0 using the correction method recommended by the Design Institute for Emergency Relief System (DIERS) and developed by Fisher [1]. The results showed that this method works well at low concentrations. However, at the highest concentration, fast heating rates (up to 600 °C/min) were observed in the low phi factor equipment. These fast heating rates, most probably caused the equipment to loss its adiabaticity, and the scale up of the temperatures and self-heating rates did not longer give reliable results. This means that the estimation of experimental variables such temperature and rate of temperature rise (used for vent sizing calculations), directly from the data obtained at lab scale, even when using an advance low phi factor equipment, can result in under-conservative design calculations.