GENERALIZED GRAPHICAL METHOD TO DETERMINE THE REQUIRED MEG AND METHANOL INJECTION RATE FOR NATURAL-GAS HYDRATE INHIBITION

摘要

In the 87th annual GPA convention, we presented a new shortcut/graphical method for inhibition of hydrate formation temperature. Four diagrams were presented to predict the required mono ethylene glycol (MEG) weight percent in the rich solution and flowrate for the desired depression of hydrate formation temperature of natural gases with relative densities of 0.6 to 0.8. The method was applicable for a wide range of pressures (3 to 9 MPa), wet gas temperatures (20 to 50 °C) but its application was limited to only MEG with lean concentration of 80 weight percent. In order to overcome this shortcoming, we are extending our graphical method to other lean MEG concentrations and methanol (MeOH) in this paper. We used a slightly different methodology to generate the required diagrams for natural gases with relative density of 0.6 to 0.8 at pressures of 3, 5, 7 and 9 MPa and wet gas temperatures of 20, 30, 40 and 50 °C. These proposed charts are based on rigorous computer simulation. The accuracy of this generalized shortcut method is compared with rigorous computer simulation results obtained by process simulators. In addition, the results of the proposed method were compared with the available experimental data. Overall, excellent agreements have been obtained.