Advanced Model-Based Optimization of a Natural Gas Liquid Recovery Unit

Abstract Natural gas liquids (NGLs) are the main contributor to the profitability of natural gas processing plants. During the recent period of relatively low natural gas prices, NGLs spot prices have experienced a slower drop remaining relatively steady. Therefore, switching the operation of existing facilities towards a higher NGL production can lead to a more profitable position. In this work, we develop and implement model-based optimization solutions on a selection of NGL plants in order to improve the profitability of the facility. Such analysis is meaningful only when high-fidelity validated first-principles models are employed within an equation oriented environment using rigorous mathematically formulated optimization algorithms which guarantee that the optimal solution satisfies all safety and operational constraints. In this work, an equation oriented commercial process simulator is utilized which offers unique optimization capabilities of very large and complex process flowsheets. In this paper we demonstrate the practical benefits of Advanced Model-based Optimization through a case study of an NGL Plant in Abu Dhabi. The workflow is discussed starting from model formulation and validation, to optimization and assessment of the optimal operational strategy. We also discuss how the deployment of such model-based optimization activities can be used to develop operating guidelines that allow operators to drive the plant towards optimal operation and address a range of operational situations; giving them the ability to respond to changes in the plant or economic conditions quicker and with more confidence than previously possible.