Optimization of a simple LNG process using sequential quadratic programming

•Use of standard process simulator combined with external optimization routine.•Framework for the optimization of LNG processes.•Formulation of the problem.•Efficiency and robustness of the optimization routine compared to other reported routines. The efficiency of using sequential quadratic programming (SQP) for the optimization of a PRICO process for the production of liquefied natural gas (LNG) is demonstrated. Most of the returned objective values have been better, and the execution times much lower, than in most previously published work on similar optimization cases. The optimization runs discussed in this paper require around 5min of execution time.