(42p) Modelling and Simulation of Diffusion Effect on the Glycol Dehydration Unit of a Natural Gas Plant

Mathematical models of the absorber of a glycol dehydration facility was developed using the principles of conservation of mass and energy. A model that predicts the variation of the water content of gas in mole fraction across the column was developed. Similar models were developed for the variation of the gas and liquid (TEG) temperatures across the packing height. The models developed contain contributions from bulk and diffusion flows. The effect of diffusion on the process occurring in the absorber was studied in this work. The models were validated using the initial conditions in the plant data from a gas processing plant to ascertain if the outlet conditions predicted by the models meet the plant data outlet requirements. The results obtained showed a good match due to the effect of diffusion observed between z=0 and z=0.004m. The results obtained showed that the effect of diffusion was noticed between z=0 and z=0.004m. A deviation from plant data of 0% was observed for the gas water content at a residence time of 20 seconds, at z=0.004m. Similarly, deviations of 1.584% and 2.844% were observed for the gas and TEG temperatures. A reasonable conclusion to draw from this study is that the effect of diffusion on absorption of a flow process occurs over small average height in the absorber.