• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.11 no.5
• /
• pp.1747-1753
• /
• 2010

In this study, a comparative study was performed to predict the vapor-liquid equilibria with maximum azeotropic pressure for ethanol-benzene binary system between an equation of state model and a liquid activity coefficient model. Peng-Robinson equation of state model with a Panatiotopoulos mixing rules (PRP) was used and NRTL liquid activity coefficient model proposed by Renon was selected. The PRP model, even though it has only two binary adjustable parameters, was not inferior to the NRTL model to predict vapor-liquid equilibria for low pressure region of ethanol-benzene system and showed a better prediction capability for high pressure region of ethanol-benzene system than the NRTL model with three binary interaction parameters.

• Clean Technology
• /
• v.22 no.4
• /
• pp.241-249
• /
• 2016

In this study, comparative work has been performed between two-columns and three-columns configurations for an extractive distillation process to produce highly purified ethanol with not less than 99.7 wt% using dimethyl sulfoxide (DMSO) and ethylene glycol (EG) as extracting agents. Optimal ethanol concentration at a concentrator top stream which minimized the total reboiler heat duties was determined for a three-columns configuration for two different solvents. For the thermodynamic model, NRTL liquid activity coefficient model was used and PRO/II with PROVISION 9.4 at Schneider electric company was utilized. DMSO was proved to be a better solvent than EG and three-columns configuration is better than two- columns configuration in the total utility consumptions since some of the liquid water contained in the feed stream was removed at a concentrator bottom liquid stream.

• Clean Technology
• /
• v.18 no.4
• /
• pp.347-354
• /
• 2012

In this study, simulation works have been performed for the $CO_2$ removal process contained in the DME production process using NMP (N-methyl-2-pyrrolidone) as a solvent. PRO/II with PROVISION release 9.1 at Invensys was used as a chemical process simulator and NRTL activity coefficient model with Henry's law option and Soave-Redlich-Kwong equation of state were used for thermodynamic models. For the determination of the binary interaction parameters in NRTL model, regression works have been performed to match the experimental thermodynamic data. Optimal feed tray location which minimizes the reboiler heat duty was determined.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.18 no.10
• /
• pp.136-152
• /
• 2017

The thermodynamic models, PC-SAFT (Perturbed-Chain Statistical Associated Fluid Theory) state equation and the Two-model approach liquid activity coefficient model NRTL (Non Random Two Liquid) + Henry + Peng-Robinson, for modeling the Rectisol process using methanol aqueous solution as the $CO_2$ removal solvent were compared. In addition, to determine the new binary interaction parameters of the PC-SAFT state equations and the Henry's constant of the two-model approach, absorption equilibrium experiments between carbon dioxide and methanol at 273.25K and 262.35K were carried out and regression analysis was performed. The accuracy of the newly determined parameters was verified through the regression results of the experimental data. These model equations and validated parameters were used to model the carbon dioxide removal process. In the case of using the two-model approach, the methanol solvent flow rate required to remove 99.00% of $CO_2$ was estimated to be approximately 43.72% higher, the cooling water consumption in the distillation tower was 39.22% higher, and the steam consumption was 43.09% higher than that using PC-SAFT EOS. In conclusion, the Rectisol process operating under high pressure was designed to be larger than that using the PC-SAFT state equation when modeled using the liquid activity coefficient model equation with Henry's relation. For this reason, if the quantity of low-solubility gas components dissolved in a liquid at a constant temperature is proportional to the partial pressure of the gas phase, the carbon dioxide with high solubility in methanol does not predict the absorption characteristics between methanol and carbon dioxide.