Modeling and Simulation of CO2 Absorption into Promoted Aqueous Potassium Carbonate Solution in Industrial Scale Packed Column

Abstract

Carbon dioxide gas is a harmful impurity which is corrosive and it can damage the utilities and the piping system in industries. Chemical absorption is the most economical separation method which is widely applied in chemical industries for CO2 removal process. Hot potassium carbonate (K2CO3) is the most effective solvent that has been used extensively, especially for the CO2 separation process from gas synthesis and natural gas. This paper aims to develop mathematical model for investigating the CO2 absorption into promoted hot K2CO3 solution in industrial scale packed column in an ammonia plant. The CO2 was removed from the gas stream by counter-current absorption in two stages column. To represent the gas-liquid system, a rigorous mathematical model based on the two-film theory was considered. The model consists of differential mass and heat balance and considers the interactions between mass-transfer and chemical kinetics using enhancement factor concept. Gas solubility, mass and heat transfer coefficients, reaction kinetics and equilibrium were estimated using correlations from literatures. The model was validated using plant data and was used to compute temperature and concentration profiles in the absorber. The variation of CO2 recovery with respect to changes in some operating variables was evaluated. The effect of various kinds of promoters added into K2CO3 solution on the CO2 recovery was also investigated. The simulation results agree well with the plant data. The results of the simulation prediction, for the absorber pressure of 33 atm with a lean flow rate of 32,0867 kg/h, temperature of 343 K, and semi lean flow rate of 2,514,122 kg/h, temperature of 385 K, showed %CO2 removal of 95.55%, while that of plant data is 96.8%.

New Approaches in Modeling and Simulation of CO2 Absorption Reactor by Activated Potassium Carbonate Solution

“…The setting up of the mathematical model of the packed bed reactor involves the following [23,33,34]: expression of chemisorption rate; characterization of phases circulation regime; characterization of thermal regime.…”

“…(a) Total heat balance: By using simplifying assumptions for stationary operation regime and adiabatic regime, the following equations may be written [33]:…”

“…where dh g and dh L can be expressed by deriving the Equations (29) and (30). 28into Equation (33) and then, substituting the expressions for dh g , dh L and q g , the following equations for the gas phase temperature profile are obtained:…”

Enhancement of CO2 Absorption into K2CO3 Solution by Cyclohexane in a High-Shear Reactor

“…Chemical absorption is currently the most extensively used method in postcombustion CO 2 capture. , The method is based on CO 2 absorption by chemical reactions in absorbents. Aqueous potassium carbonate is a well-used solvent in CO 2 absorption due to the low cost, low energy consumption for regeneration, high chemical stability, and low corrosivity to pipeline . However, a slow chemical reaction rate with CO 2 at low temperature and normal pressure is the major disadvantage of potassium carbonate compared with amine solvents.…”

Preface, BCREC Vol. 10 No. 2 Year 2015

“…Modeling and optimization of chemical reactor were studied by Altway et al [2] and Sadighi et al [3] in the second and twelfth articles in this issue. The studies were focused on modeling and simulation of CO2 absorption into promoted aqueous potassium carbonate solution in industrial scale packed column as well as optimizing an industrial scale naphtha catalytic reforming plant using a hybrid artificial neural network and genetic algorithm technique, respectively.…”