Eventos Anais de eventos
COBEM 2019
25th International Congress of Mechanical Engineering
Loss of Methanol and Monoethylene Glycol in VLE and LLE Prediction of Partition Coefficient
Submission Author:
Moisés Marcelino Neto , PR
Co-Authors:
Felipe Cesar Jacomel, Thales Sirino, Moisés Marcelino Neto, Dalton Bertoldi, Rigoberto Morales
Presenter: Moisés Marcelino Neto
doi://10.26678/ABCM.COBEM2019.COB2019-1864
Abstract
Phase equilibria of water-alcohol-hydrocarbons are important when it comes to flow assurance issues in the petroleum industry. Thermodynamic inhibitors (usually alcohols and glycols, such as methanol and monoethylene glycol) change the thermodynamic equilibrium itself, thus avoiding the hydrate zone. Accurate results for the loss of the volatile inhibitor in the gas or condensate phase (partition) are of extreme importance for the oil and gas industry. In this work, a flash algorithm using the Cubic-Plus-Association (CPA) equation of state was developed to estimate the partition of each component (water, hydrate-forming gas and inhibitor) in any phase over a wide range of temperatures and pressures in vapor-liquid equilibrium (VLE) and liquid-liquid equilibrium (LLE). Different temperature-dependent functions were optimized and evaluated for the CPA binary interaction parameters. The flash was applied to several systems with water, methane, ethane, propane, carbon dioxide, methanol and monoethylene glycol (MEG). The results were then compared with experimental data available in the literature. The loss of methanol to the gas and or condensate phases was satisfactorily predicted. Yet, the CPA underestimated the loss of MEG to the gas phase in a gas mixture containing carbon dioxide. The average absolute deviation for the predicted loss of methanol and monoethylene glycol ranged between 3 - 75%.
Keywords
vapor-liquid equilibrium, liquid-liquid equilibrium, CPA, Cubic Plus Association (CPA), hydrate inhibitor, partition
