Chemical process route selection based upon potential environmental risk of chemical releases

Chemical process route selection is a key decision taken during the preliminary design stage of chemical plant development. This work presents a risk-based methodology that can be used to select the most inherently environmentally friendly chemical process route among alternate routes to produce a chemical. An index called Inherent Environmental Risk Index for Chemical Release (Chem-IERI) is proposed which represents the potential environmental risk due to a total loss of containment event in the plant. The risk index incorporates three parameters, namely the magnitude of environmental impact, the occurrence frequency of the accidental chemical release event that results in the environmental impact and the vulnerability of the environmental element where the impact is observed. Eight environmental impacts are considered and a methodology to estimate the vulnerability of environmental elements to these impacts is proposed. A higher index value indicates a higher environmental risk. The index developed was applied to assess four possible process routes to produce acetone. Propene oxidation process route showed the lowest Chem-IERI value while cumene oxidation process route showed the highest indicating the least inherent environmental friendliness.