Environmental impact reduction through simultaneous design and scheduling

A systematic framework was proposed as well as the associated mathematical formulation for process design and scheduling while simultaneously addressing economic and environmental objectives. A procedure is developed to enable the development of a process retrofitting scheme while incorporating scheduling issues for typical process and market variations. The devised procedure is illustrated with a case study on an oil refinery. The scheduling activities of oil refineries are becoming difficult due to newly introduced environmental regulations, e.g., SO_x, NO_x, wastewater discharge, etc. For a variable feedstock and/or market demand of product quantities and qualities, a retrofitting and scheduling approach is established. Several units are considered including the crude distillation units, FCC, hydrocracker, hydrtreater, hydrodeslfurizer, catalytic reformer, and delayed coker units. The design and operational performance, supply, demand, technical constraints, environmental impact are all included on optimization formulation. The solution established insightful synergisms and tradeoffs. Various results are discussed for the case study and for the broader aspects of a typical processing facility. This is an abstract of a paper presented at the 2007 AIChE Annual Meeting (Salt Lake City, UT 11/4-9/2007).