Integrating Safety Issues in Conceptual Design of Solvent Processes

Integration of safety aspects in process design has become of utmost significance in light of many chemical process incidents that occur frequently. Solvents are commonly applied in various processes and operations but at the same time they are extremely hazardous materials. Many incidents involving fire and explosion events have been escalated because of large amounts of flammable solvents being used in the process. Toxicity hazards are also of concern to many workers in the plant and nearby local residents. Safety can be integrated into the design of solvent processes by means of an optimization formulation. While maximizing profits and satisfying constraints on product quality requirements, additional constraints can be placed on several safety requirements such as a maximum permissible release amount, maximum concentration levels reached upon release of material and risk associated with fire/explosion/toxic events. In this work, a simple case study on liquid -liquid extraction has been shown and the effects of applying such safety constraints on the different process variables have been assessed. Issues relating to the probable reduction in productivity at the cost of safety will be described as well.