A CHEMICAL APPROACH TO INHERENT SAFETY

Inherent safety is traditionally pursued by reducing the chemical inventory in order to minimise the quantities of toxic and flammable materials that are available for release in the event of an incident. This is often achieved by changing from batch to semi-batch or continuous operation. An alternative approach to inherent safety is to consider the process in addition to the plant. This requires a thorough understanding of the chemistry including the thermo-kinetics of the main reaction and of any possible side reactions that could occur in the event of a maloperation. Once the hazards associated with the process have been identified, addition rates and operating temperatures can be set so that any accumulation/decomposition problems are eliminated or minimised. In addition to the above there is a third and often rarely considered option to inherent safety. This involves the investigation of different processes, including their associated hazards, available to manufacture a desired product before the final process is selected and developed. A careful study of the proposed manufacturing process can sometimes identify an inherently safer route for production. This chapter will describe with examples this chemical approach to inherent safety.