Integrating Simulation in Optimal Synthesis and Design of Natural Gas Upstream Processing Networks

Abstract

A natural gas upstream processing network consists of several main processing units. Many process configurations are available for selection, and the choice of technologies can be vast. There is no single technology or process configuration that is superior in all aspects. Thus, there is a need for a mathematical model that considers different flowsheet configurations and operating mode options and selects optimally among them. In this paper, a comprehensive design and operational mixed integer programming model is presented for superstructure optimization to optimally select the most cost-effective pathway in natural gas upstream processing networks. The key processing units of the considered processing network include stabilization, acid gas removal, dehydration, sulfur recovery, natural gas liquid (NGL) recovery, and NGL fractionation. The developed optimization model considers a superstructure with all available technologies for each processing step as well as mode of operation, such as variations in temperature and pressure which impacts the product yields. These units have been simulated using ASPEN Plus to determine the yields of different units for each design alternative under different operating modes. The bilinear terms in the resulting mixed integer nonlinear programming (MINLP) model are linearized based on either input or output streams, whichever are less in number. The model has been applied to design and operate optimally the natural gas upstream processing network. Two illustrative case studies are presented to show the applicability of the overall framework and formulated models. 2017 American Chemical Society.