Iranian Journal of Chemical Engineering (IJChE)

Abstract In this study, the process of capturing CO₂ by using an aqueous MDEA solution under the operating conditions of the concentration range of 10-98 wt% of MDEA, temperature range of 303-323K and atmospheric pressure is investigated. Most researchers have measured the effect of pressure changes on the loading, but in this work, we have investigated the effect of changing the concentration of amine on the loading. We employed the apparatus introduced by Pahlavanzadeh et al. to evaluate the solubility of carbon dioxide in the aqueous solutions of N-methyldiethanolamine (MDEA). The results indicate that the maximum absorption of CO₂ takes place in concentration of between 40-50 wt% of MDEA. Subsequently, the Cubic-Two-State Equation of State (CTS EoS) was improved and used to describe the solubility of CO₂ in aqueous MDEA solutions in a wide range of concentrations and temperatures. This equation, referred to as CTS^DH, includes three terms relating to the different intermolecular interactions happening in electrolyte solutions. The same EoS was used for vapor and liquid phases. Model parameters were adjusted according to the experimental results of this work and other researches. Using the adjustable parameters from this work, the model successfully approximated CO₂ loading under a wide range of functional conditions. The evaluation of model results with experimental data showed the average absolute percent deviation (AAD%) to be 7.05%, indicating a satisfactory alignment between model predictions and Measured results.

Abstract The gas antisolvent (GAS) process has been employed for pharmaceutical micronization. Ampicillin was dissolved in organic solvent and carbon dioxide as an antisolvent was injected into this solution, consequently, volume expansion and sharp reduction in liquid solvent power were shown. The particles in GAS process are not seen in any operating conditions. Thermodynamic modeling of GAS can evaluate the operating conditions. In this project, the‌ effect of solvent on optimal thermodynamic conditions of the binary system (CO2, solvent) and ternary system (CO2, solvent, ampicillin) were investigated. The relative change in molar volume in different solvent (ethanol, 1-propanol, 1-butanol, and 1-pentanol) was studied for determination of the optimum operating conditions. The combination of Peng-Robinson EOS and Vidal and Michelsen mixing rule (LCVM) was selected to determine the optimum operating condition of the GAS process. The effect of solvent on minimum pressure was investigated. The calculated Pmin was 70, 70.86, 72.2 and 73.4 bar for ethanol, 1-propanol, 1-butanol, and 1-pantanol at, 308.15 K respectively. According to modeling results, when the molecular weight of the solvent was increased, the value of Pmin was increased.