(147b) Inherent Risk Assessment

Quantitative Risk Assessment (QRA) has been a very popular and useful methodology which is widely acceptable by the industry over the past few decades. QRA is typically carried out at a stage where complete plant has been designed and sited. At that time, the opportunity to include inherent safety design features is limited and may incur higher cost. This paper proposes a new concept to evaluate risk inherent to a process owing to the chemical it uses and the process conditions. The Inherent Risk Assessment (IRA) is integrated with process design simulator (HYSYS) to provide necessary process data as early as the initial design stages, where modifications based on inherent safety principles can still be incorporated to enhance the process safety of the plant. The IRA consists of two components which calculate the probability and the consequences relating to possible risk due to major accidents. Case studies on the released of flammable material demonstrate that IRA is capable to identify potential high risk of process streams. The modifications using inherent safety principles make the process under consideration inherently safer. Since IRA is fully integrated with HYSYS, re-evaluation of the inherent risk takes very little time and effort. The IRA addresses the lack of systematic methodology and technology, which is one of the barriers to designing inherently safer plants.