Optimization Of CO2 Capture Process Research Articles

Optimization of CO2 Capture Process Using Dry Sodium-Based Sorbents

Sodium carbonate (Na2CO3) supported by gamma-alumina (g-Al2O3) is one of the best sorbents for CO2 capture in economic terms because of its low raw material cost and excellent performance in low-temperature operation. The fundamental goal of this study is to optimize the operating conditions of CO2 adsorption by Na2CO3/Al2O3 sorbent in a fixed bed reactor. The sorbent characterization was studied using BET, SEM, XRF, and XRD analyses, and the sorbent structure was compared before and after the carbonation reaction. Moreover, the effects of side reactions on the adsorption process were investigated. The Response Surface Methodology (RSM) was used with Box-Behnken Design (BBD) to design the experiments. The optimum conditions are introduced at the point where initial CO2 capture capacity and deactivation rate constants are as high and as low as possible, respectively. The optimum values of the variables corresponding to the temperature of 50°C, vapor pretreatment time of 9 min, and H2O/CO2 mole ratio of 1. The amounts of initial CO2 capture capacity and deactivation rate constant in the optimum conditions were obtained to be 39.238 mgCO2/gsorbent and 0.416 min-1, respectively.

Improving the energy cost of an absorber-stripper CO2 capture process through economic model predictive control

Carbon dioxide (CO2) is the major source of greenhouse gas and its capture and recovery is the key to effective reduction of CO2 emissions. Optimization of the CO2 capture process plays a critical role in the reduction of energy cost. The current strategy only deals with the steady state optimization of the CO2 capture process but the CO2 concentration in the plant varies with time and as a result a dynamic study of the economic assessment will reflect the true cost better. The economic model predictive control (EMPC) that combines real-time economic process optimization and feedback control is applied to the optimization of CO2 capture process. The large energy requirement for solvent regeneration is optimized in dynamic settings. Unlike the conventional steady state consideration of the economic performance assessment, the proposed method allows the cost to be adjusted to the volatile market conditions that varies rapidly. Case studies are then presented to show the benefits of the EMPC optimization for CO2 capture process.

Economic model predictive control of an absorber-stripper CO2 capture process for improving energy cost

Carbon dioxide (CO2) is the major source of greenhouse gas and its capture and recovery is the key to effective reduction of CO2 emissions. Optimization of the CO2 capture plays a critical role in the reduction of energy cost. CO2 concentration in the plant varies with time and a dynamic study of the economic optimization reflects the true cost better when compared to the current strategy of the steady state optimization. The economic model predictive control (EMPC) that combines real-time economic process optimization and feedback control is applied to the optimization of CO2 capture process. The large energy requirement for solvent regeneration is optimized in dynamic settings. Unlike the conventional steady state consideration of the economic optimization, the proposed method allows the cost to be adjusted to the changing condition such as feed composition and utility cost. Case studies are then presented to show the benefits of the EMPC optimization for CO2 capture process.

Chemical speciation of CO2 absorption in aqueous monoethanolamine investigated by in situ Raman spectroscopy

A quantitative analysis method of chemical species in liquid phase during CO2 absorption into monoethanolamine was developed for Raman spectroscopy. Band envelopes in the spectral region between 300 and 3100cm−1 were resolved with Gaussian Lorentzian function. Spectroscopic characterization of MEA, protonated MEA, carbamate, bicarbonate, carbonate and molecular CO2 in aqueous was performed. Calibration curves were constructed with area ratio plotted against species concentration. Concentration of individual chemical species in liquid phase can be systematically determined using the correlations introduced. Experiments of CO2 solubility in aqueous MEA were carried out for pressure ranges from 1 to 60bar and three temperatures (303.15, 313.15 and 323.15) K with in situ Raman measurement. Absorption capacity was determined with conventional gas pressure drop method and newly developed Raman spectroscopic analysis method based on total carbon containing species in liquid phase. Results depict good accuracy and reproducibility of Raman measurement method. Chemical speciation during CO2 absorption into aqueous solution of 30% MEA at pressure up to 60bar was evaluated. The findings from present work will improve the understanding of phase equilibrium behavior associated with absorption reactions and can be employed for monitoring, analysis and optimization of CO2 capture process.

Study on the Effect of Preparation Parameters of K<sub>2</sub>CO<sub>3</sub>/Al<sub>2</sub>O<sub>3</sub> Sorbent on CO<sub>2</sub> Capture Capacity at Flue Gas Operating Conditions

In this paper, study on the effect of preparation conditions of K2CO3/Al2O3 sorbent was done. Box-Behnken design was applied to study the influence of four parameters involve initial solution concentration, impregnation time and calcination step temperature and time. A quadratic model was used to correlate the sorbent capture capacity. The model was used to calculate the optimum conditions for preparing sorbent. From the analysis of variance (ANOVA), the most influential factor on each experimental design response was identified. The potassium-based sorbents used in this study were prepared by impregnating K2CO3 on Al2O3 support. The CO2 capture capacity was measured in the presence of H2O in a fixed-bed reactor at CO2 capture temperature of 60°C using breakthrough curves. The optimum sorbent prepared by this method showed CO2 capture capacity of 77.21 mg CO2/g sorbent. It was observed that the experimental values obtained were in good agreement with the values predicted by the model, with relatively small errors between the predicted and the actual values. The results obtained in this study can be used as basic data for study on design and operating condition optimization of CO2 capture process using these sorbents.