A graphical method for assessing inherent safety during research and development phase of process design

Abstract

Hazard reduction and elimination play a major role in designing a user-friendly plant in order to prevent accidents. To achieve this, safety evaluation on the properties of the chemicals and the process during the early design stage (also known as inherent safety assessment) is important to understand the hazards posed by the process involved. Different approaches have been proposed for inherent safety assessment methods, e.g. the index-based, simple graphical and computer aided methods. These methods evaluates different alternatives of process routes through scores assignment and rank them accordingly from the safest to the most hazardous process route. This paper proposes a Graphical Descriptive Technique for Inherent Safety Assessment (GRAND) for inherent safety evaluation during the research and development (R&D) stage of process design. GRAND is extended to 2-Dimensional Graphical Rating (2DGR) technique and may serve twofold purposes, (1) highlight chemical and process properties that contribute significantly to the maximum hazards through visualization (2) grouped the process routes evaluated three coloured regions which are red, yellow and green indicating the most hazardous, hazardous and the least hazardous levels respectively. Methyl methacrylate (MMA) manufacturing routes were chosen as a case study to illustrate the usage of the root-cause analysis as well as the 2DGR. The root-cause analysis of MMA manufacturing routes shows that GRAND Total Score of C2/PA based route is affected the most by hydrogen and formaldehyde. The 2DGR shows that ACH based route is assigned in the red region indicating it as the most hazardous route while i-C4 and TBA based route are assigned in the green region indicating them as the least hazardous routes in MMA manufacturing process.