Effect of various types of equations of state for prediction of simple gas hydrateformation with or without the presence of kinetic inhibitors in a flowmini-loop apparatus

摘要

This paper compares the effects of using various types of equations of state (PR,~1SRK,~2ER,~3PT~4and VPT~5)on the calculated driving force and rate of gas consumption based on the Kashchiev and Firoozabadi modelfor simple gas hydrate formation for methane, carbon dioxide, propane and iso-butane with experimentaldata points obtained in a flow mini-loop apparatus with or without the presence of kinetic inhibitors atvarious pressures and specified temperatures. For this purpose, a laboratory flow mini-loop apparatuswas set up to measure gas consumption rate when a hydrate forming substance (such as C_1,C_3,CO_2andi-C_4) is contacted with water in the presence or absence of dissolved inhibitor under suitable temperatureand pressure conditions. In each experiment, a water blend saturated with pure gas is circulated up to arequired pressure. Pressure is maintained at a constant value during experimental runs by means of therequired gas make-up. The total average absolute deviation was found to be 15.4%, 16.3%, 15.8%, 17.8%and 17.4% for the PR, ER, SRK, PT and VPT equations of state for calculating gas consumption in simple gashydrate formation with or without the presence of kinetic hydrate inhibitors, respectively. Comparisonresults between the calculated and experimental data points of gas consumption were obtained in flowloop indicate that the PR and ER equations of state have lower errors than the SRK, VPT and PT equationsof state for this model.