MODELING OF NATURAL GAS DEHYDRATION IN A SUPERSONIC SEPARATOR: CONDENSATION PROCESS

The purpose of this report is to provide an overview of the author's Final Year Project. Natural gas, as it is used by consumers, is much different from the natural gas that IS brought from underground up to the wellhead. The natural gas used by consumers IS composed almost entirely of methane. However, natural gas found at the wellhead, IS by no means as pure. The gas commonly exists in mixtures with hydrocarbons, water vapor, hydrogen sulfide (H2S), carbon dioxide (C02), helium, nitrogen and other compounds. Most of the liquid. free water associated with extracted natural gas is removed by separation methods at or near the wellhead. However, the removal of the water vapor that exists in solution m natural gas requires a more complex treatment. This treatment consists of 'dehydrating' the natural gas, which usually involves one of two processes: either absorption. or adsorption. Absorption occurs when the water vapor is taken out by dehydrating agent while adsorption occurs when the water vapor is condensed and collected on the surface. The research started with literature review to investigate suitable model to be used, followed with the construction of nozzle geometry with specified meshes. The project describes a conservative two-dimensional compressible numerical model for supersomc spontaneous condensing steam flow based on the classical nucleation theory. The project aims to model the condensation behavior of liquid water in a supersonic convergent-divergent nozzle separator. Currently, there is no research has been done to study the behavior of the water vapor to water liquid formation and growth in relation with the oil and gas field. Quantitative validation of the numerical model was accomplished and the results showed a good agreement between numerical simulation and the result from published literature