(203k) Optimal Facility Layout Considering Simultaneously Economic and Safety Aspects

Plant layout design was traditionally performed based solely on economic criteria, this lead to unsafe processes which have been the cause of some of the most disastrous accidents in the chemical industry. Thus, in the present it is important to develop new methodologies which consider simultaneously the risk evaluation and the cost associated to the plan layout design, which implies the distribution of facilities in a specific terrain. Most of the methodologies that consider both aspects are limited to the distribution of facilities in new plants (Díaz-Ovalle et al. 2010; Vázquez – Román et al. 2010; Jung et al.2010). However, there are numerous chemical plants which require the relocation of facilities to correct the inherently unsafe design, or in which a plant expansion may require the increase of capacity of existing equipment or the addition of new equipment. In any of these scenarios the optimal distribution of new and existing facilities is of paramount importance. In this work a general methodology for the distribution of new and existing facilities in a chemical plant is proposed. The risk is assessed considering two types of potential accidents Boiling-Liquid Expanding-Vapor (BLEVE) and Vapor Cloud Explosion (VCE).The problem is formulated as  multi objective mixed integer linear problem (MO MILP), which determines the optimal localization of the facilities in a given terrain while minimizing the cost and the risk. To show the application of the proposed methodology, the distillation process  of hexane-heptane (AIChE/CCPS, 2007) was analyzed. Results show the importance of selecting an optimal distribution of new facilities and/or relocation of existing facilities in an existing process in order to reduce the risk at a minimum cost. This way existing processes designed based on economic standards can be readjusted to be safer.