Toward Economically and Environmentally Optimal Operations in Natural Gas Based Petrochemical Sites

Abstract

In this work, we address the economic and environmental optimization of the operations in a natural-gas-based petrochemical complex through multiobjective optimization. The site is represented by a mathematical model that includes linear and nonlinear simplified models for single equipment and plants to calculate site production levels, taking into account main operating variables, utility consumption, intermittent delivery, inventory level profiles and product distribution. The resulting multiperiod, mixed integer nonlinear programming (MINLP) models are implemented in GAMS. The bicriteria MINLP model is solved with the ε-constraint method. The obtained Pareto-optimal curve shows the trade-off between the economic and environmental aspects to pursuit sustainable operations of an existing integrated petrochemical complex. The environmental metrics is Global Warming Potential. ReCiPe is used for life cycle assessment and its 18 midpoint impact indicators and three end-point indicators are further analyzed for the petrochemical complex. The optimal solutions show that the environmental performance of the industrial cluster can be improved by a different distribution of processed raw material and intermediate products between the plants, as well as the means of transportation.