(81ag) USING Integrated Toxic RELEASE Consequences ANALYSIS TOOL for Inherently Safer Design of PROCESS PLANT at PRELIMINARY Design STAGE

Toxic release is one of major accidents in process plant that caused many fatalities. Some examples of major disaster due to the toxic release are the tragedy of TCDD release in Seveso, Italy (1976) and MIC release in Bhopal, India (1984). Some common and popular practices to prevent such accidents in process plant are by installation of add-on protective system and safe operation procedure. These techniques are proven effective to minimize the probability of such accidents and to control the release of toxic materials, nevertheless the hazard is still remaining in the process plant. In case the protective systems and other safeguarding systems fail to function, the toxic materials will be released that could cause potential major accident. This paper reports on an alternative design approach to avoid or minimize the toxic release accidents by utilizing an inherent safety concept. A process design tool was developed by the integration of process design simulator, iCON from PETRONAS with toxic release consequence model created in MS-Excel spreadsheet. The consequence model was based on the method recommended by Center for Chemical Process Safety (CCPS). The toxic release consequence was validated with case studies from established literatures and the results are in good agreement. This unique prototype tool allows the consequence analysis of potential toxic release to be done early in preliminary design stage. If the design fails to meet the limitation of toxic release criteria, the improvement can be done using inherent safety concept to avoid or minimize the toxic released consequence. A case study was conducted to show the applicability of the concept using practical scenario of ammonia release from a purification column. The results have proven that the concept can be applied to avoid or minimize the potential toxic release consequence by utilizing the developed tool early in preliminary design stage. More studies are currently carried out to explore the full capabilities of the developed prototype tool for inherently safer design options prior to commercial applications.