چكيده به لاتين
The presence of CO2 in the atmosphere as a greenhouse gas leads to environmental problems such as climate change, acidification of the oceans and raises the sea level. Also, its existence in natural gas causes corrosion and decreases the thermal value of the gas. Therefore, the removal of CO2 in recent years has been one of the most important environmental operations.
Nowadays, one of the most common methods for CO2 capture is absorption in aqueous alkanolamine solutions. According to their functional groups, alkanolamines are mainly divided into three groups. Among them, the third type of alkanolamines are used more due to the selective absorption of H2S and the increase in the amount of CO2 absorbed specially when using a mixture of alkanolamines. Absorption of CO2 in an aqueous solution of alkanolamine is a vapor-liquid equilibrium system for which phase equilibrium, chemical equilibrium and mass balance equations must be solved simultaneously. For phase equilibrium, two general approaches are used, the φ-φ approach in which the liquid and and vapor phases are modeled using an electrolyte equation of state (ePR, eSAFT, CPA), and the γ-φ approach which is modeled by using an activity coefficient model (extended UNIQUAC, eNRTL, Deshmukh-Mather) for the liquid phase and an equation of state for the gas phase.
In this work, the Deshmukh-Mather gibbs free energy model is modified by introducing a new term that accounts for triplet interactions. The modification is called the modified Dashmukh-Mather model and was used to model the water-acid gas-alkanolamine systems. MDEA-CO2-H2O, AMP-CO2-H2O, DEA-CO2-H2O, MEA-CO2-H2O, MOR-CO2-H2O, MDEA-DEA-CO2-H2O, AMP-DEA-CO2-H2O, MDEA-MOR-CO2-H2O, and MDEA-H2S-H2O systems were modeled using the modified Dashmukh-Mather model. The results showed that, in the temperature and pressure ranges considered, the modified Dashmukh-Mather model had higher accuracy in comparison to the original Deshmukh-Mather model. The average absolute deviation percentage deviation of 1.22, 1.07, 1.83, 2.34, 1.14, 1.66, 1.38, 1.33, and 2.70 are obtained for the above systems, respectively.
