Design Optimization of an LPG Thermal Cracker for Multiple Objectives

Abstract

Ethylene and propylene, building blocks of the petrochemical industries, are mostly produced by steam cracking of hydrocarbons. In our recent work (Nabavi, Rangaiah, Niaei and Salari, Multiobjective Optimization of an Industrial LPG Thermal Cracker using a First Principles Model, Ind. Eng. Chem. Res. 2009, 48, 9523-9533), operation of an industrial liquefied petroleum gas (LPG) cracker was optimized for several sets of two and three objectives. In this work, optimization of an LPG cracker design is investigated for multiple objectives. The objectives considered are maximization of annual ethylene and propylene production, selectivity and run length, and minimization of severity and total heat duty per year. The elitist non-dominated sorting genetic algorithm adapted with the jumping gene operator, NSGA-II-aJG is used to solve the multi-objective optimization problems. The results of design optimization for multiple objectives are compared with those for operation optimization.