Introduction Various methods have been used to evaluate the ther- mal hazards of reactive chemicals, such as iodoform vulcanizate [1], butadiene-acrylonitrile rubber [2], and cyclohexanone [3], but few studies have focused on MEKPO. In the last four decades, many thermal explo- sions have been caused by MEKPO in Taiwan, Japan, Korea and China, making it as one of the most hazard- ous materials in Asia, as shown in Tables 1–3 [4]. In Taiwan, one of the worst accidents is the Yung-Hsin explosion in 1996. The initial fire was due to an uncon- trollable oxidation reaction at the process site that eventually extended to the tank yard. This accident caused 10 deaths and 47 injuries. In Tokyo, 3 600 kg (8 000 lbm) of MEKPO exploded, killed 19 and injured 114 in 1964. The damages in this period from accidents cost 1.25 million U.S. dollars [5]. In China, thermal explosions killed 5 and injured 3 people in 2003. This study evaluated and simulated the exother- mic reaction for MEKPO, along with H 2 SO 4 or NaOH by using safety and kinetic parameters. MEKPO is a typical organic peroxide produced by methyl ethyl ketone (MEK) with hydrogen perox- ide (H 2 O 2 ) used as a radical source for initiation and cross-linking agent during polymerization. However, it is very sensitive to thermal and chemical pollutants or even mechanical shock. If a process is under unsafe conditions for a long time, an exothermic runaway will be induced and result in various kinds of hazards, such as fire, explosion, or toxic release. Several meth- ods have been developed concerning the determina- tion of kinetic results from thermal analysis measure- ments [6]. There is a systematic approach for experi- mentally assessing thermal hazards of materials with unstably reactive natures. Based upon these engineer- ing approaches, such as process safety management (PSM), quantitative risk assessment (QRA), safety in- dex (SI) and so on, that could be adopted to evaluate a chemical with potential reaction hazards. This study summarizes the results of the degrees of hazard incurred by MEKPO mixed with either H 2 SO 4 or NaOH. In the experiments, DSC, VSP2 and 1388–6150/$20.00 Akadémiai Kiadó, Budapest, Hungary © 2006 Akadémiai Kiadó, Budapest Springer, Dordrecht, The Netherlands Journal of Thermal Analysis and Calorimetry, Vol. 83 (2006) 1, 57–62 THERMOKINETIC MODEL SIMULATIONS FOR METHYL ETHYL KETONE PEROXIDE CONTAMINATED WITH H 2 SO 4 OR NaOH BY DSC AND VSP2 R. H. Chang 1 , J. M. Tseng 2 , J. M. Jehng 1* , C. M. Shu 3 and H. Y. Hou 2 1 Doctoral program, Department of Chemical Engineering, National Chung Hsing University, 250, Kuo-Kwang Rd., Taichung Taiwan 40227, ROC 2 Doctoral Program, Graduate School of Engineering Science and Technology, National Yunlin University of Science and Technology (NYUST), 123, University Rd., Sec. 3, Touliu, Yunlin, Taiwan 64002, ROC 3 Process Safety and Disaster Prevention Laboratory, Department of Safety, Health, and Environmental Engineering NYUST, 123, University Rd., Sec. 3, Touliu, Yunlin, Taiwan 64002, ROC In this study, a mixture of methyl ethyl ketone peroxide (MEKPO) with various contaminants, such as H 2 SO 4 and NaOH, was pre- pared in order to elucidate the cause of these accidents and the results of upset conditions. Thermokinetic parameters were acquired by both differential scanning calorimetry (DSC) and vent sizing package 2 (VSP2). In addition, we simulated the thermokinetic pa- rameters and created kinetic models for the specific contaminants. The results indicate that the thermal hazard of MEKPO is less than that of the mixed MEKPO with the above-mentioned contaminants. Consequently, the evaluated parameters could be used to prevent any unexpected exothermic runaway reaction or to alleviate hazards to an acceptable extent, if such a reaction occurs. Keywords: contaminants, exothermic runaway reaction, kinetic models, methyl ethyl ketone peroxide, thermokinetic parameters Table 1 Selected thermal explosion incidents caused by thermal decomposition of MEKPO in Taiwan since 1979 [4] Year Location Injuries Fatalities Hazard 1979 Taipei 49 33 explosion storage 1984 Taoyuan 55 5 explosion reactor 1989 Taoyuan 5 7 explosion tank 1996 Taoyuan 47 10 explosion tank 2001 Yunlin 0 0 explosion laboratory * Author for correspondence: jmjehng@dragon.nchu.edu.tw