Abstract
In separation of acidic gasses from natural gas, synthesis gas and refinery gasses chemical solvents such as MEA, DEA, MDEA and DIPA, or physical solvents such as selexol, rectizole, propylene carbonate are used. All of those solvents have imperfect functions, each having own specific advantages and disadvantages. DGA solvent regarding the effective factors for the economy of gas refinery units seem to act better than the above mentioned solvents. Simulation of an absorption column of CO2 with 40% DGA solvent has never been performed before. The available softwares are either not capable of simulating the absorption column with the DGA solvent in weight percentage of 40% (such as Aspen Hysys® and ProII simulators) or even if it is capable of, the information related to i.e. pH, ionic strength, the rate of reaction, and the heat released in the trays are not taken into accounted (such as Design II, Chemcad, Aspen Plus® simulators). While knowing parameters such as the concentration of ions and pH in removing process passages and operation conditions such as the extremity of absorption and corrosion, are important. In this research the simulation of CO2 absorption with 40% DGA solvent has been done. In addition to the temperature, pressure, concentration and mole fraction of the elements (ions and molecules), quantities of pH, ionic strength, rate of reaction and the heat released from the reaction in all of the trays are considered. Mole loading of a solute gas, CO2, in DGA solvent using the experimental results performed at various temperatures under atmospheric pressure and using the published data under the condition of different pressures were used in the simulation of a carbon dioxide absorption column. In his simulation the Kent–Eisenberg model for the liquid phase and the equation of the state of Peng–Robinson for the gas phase were utilized. The results of this work are in good agreement with design and operational data.
