A Simulation Study of CO2 Hydrate Inhibition in CO2+CH4 Seawater Mixture

In the oil and gas industry, wax deposition, scaling, corrosion, and hydrates are the main challenges in pipeline flow. Among these, gas hydrate formation is one of the most critical issues, costing the industry millions of dollars annually in mitigation efforts. Various techniques have been employed to prevent hydrate formation, with chemical inhibition being one of the most widely used methods. Several chemical inhibitors have been utilized, but methanol, ethanol, and Mono-Ethylene Glycol (MEG) hold significant commercial importance. These chemical inhibitors were used to inhibit CO2 hydrate formation in 70 mol% CO2 and 30 mol% CH4 synthetic seawater with a salinity of 3.5 mol% NaCl using PVTSim software. The PVTSim software, coupled with the Peng-Robinson (PR) Peneloux equation of state, provided accurate results for flow assurance analysis in the oil and gas industry. The software predictions for pure CO2 and CH4 hydrates were validated against experimental data available in the literature. Furthermore, the PVTSim software with the PR Peneloux fluid package was applied to salty water systems containing 5, 7, and 10 mol% concentrations of methanol, ethanol, and MEG inhibitors. Hydrate-Liquid-Vapor Equilibrium (HLVE) curves, average temperature depression, and enthalpy of dissociation were estimated. It was concluded that methanol at a concentration of 7 mol% is the most effective commercial inhibitor.