Computer aided approach for occupationally healthier chemical assessment and selection

Abstract

The purpose of this study is to develop computer aided approach of inherently healthier chemical process selection during early design stage. The study is divided into two major parts, which are to develop 1) a computer-aided index tool for inherent occupational health assessment and 2) a systematic approach to design an inherently healthier chemical process. Early hazard assessment during early design stage is critical as process modifications can still be made with high degree of freedom and at minimal cost. In this study, an electronic database was created for 1625 chemicals to provide all the chemical, physical and toxicity properties required for the index calculations for a comprehensive list of chemicals. The tool can be used to screen the alternative chemical synthesis routes to the desired product by their health properties as well as to characterise the hazard level of single process. The results of the hazards calculation are presented as a summary in tabulated as well as graphical forms which further ease the hazard assessment process. In the second part of the thesis, a flowchart is proposed for designing an inherently healthier process using Inherently Safer Design (ISD) principles (minimisation, substitution, moderation and simplification). Based on the guideline, the users may design a process which poses the lowest health hazards to workers by selecting less hazardous chemical substances and operating conditions but still within a constraint of ensuring the improved reaction chemistry is technically feasible for synthesising the desired product. With both the hazard assessment tool and design approach, the users are able to efficiently obtain reliable results.