Optimizing the Production of LNG and NGL from Arab Crudes and Wet Gases

Abstract

Natural Gas Liquids (NGL) refer to a mixture of gases that consist mostly of ethane, propane, butane and pentane. The other term which closely related to NGL is Liquified Natural Gas (LNG) which refers to methane and traces of ethane. These products can be extracted by multi-stages of compression and cooling. In addition of being the main feedstock of any petrochemical industry, NGL and LNG are used widely in the industrialized countries as a major source of energy. It is expected that their future role in both the international energy market and the petrochemical industry will continue its historical gradual growing trend.This paper presents the mathematical formulation of an economic model that was developed to optimize the production of LNG and NGL. The objective function of the model is to maximize the net cash flow return of selling LNG and NGL. The explanatory variables of the model are LNG and NGL volumes and prices, oil volume and prices, the initial costs of separators, chillers, demethanizer, compressor, partial condenser and boiler, the running cost which includes cost of refrigerants, cost of steam and other continuous operating and transportion cost. The developed model should be utilized as a useful tool to help the design of an efficient processing of natural gases. A great deal of the unlimited what if questions can be answered using this model. This paper also presents a flow sheet of the natural gas processing model. Each section of the proposed production system is presented schematically. The mathematical formulation of the computation techniques used in each section are given along with all the equation derivations.