Kwang-Joong Oh

Removal characteristics of CO2 using aqueous MEA/AMP solutions in the absorption and regeneration process

The carbon dioxide (CO2) removal efficiency, reaction rate, and CO2 loading into aqueous blended monoethanolamine (MEA) + 2-amino-2-methyl-1-propanol (AMP) solutions to enhance absorption characteristics of MEA and AMP were carried out by the absorption/regeneration process. As a result, compared to aqueous MEA and AMP solutions, aqueous blended MEA + AMP solutions have a higher CO2 loading than MEA and a higher reaction rate than AMP. The CO2 loading of rich amine of aqueous 18 wt.% MEA + 12 wt.% AMP solution was 0.62 mol CO2/mol amine, which is 51.2% more than 30 wt.% MEA (0.41 mol CO2/mol amine). Consequently, blending MEA and AMP could be an effective way to design considering economical efficiency and used to operate absorber for a long time.

Removal of carbon dioxide by absorption into blended amines: kinetics of absorption into aqueous AMP/HMDA, AMP/MDEA, and AMP/piperazine solutions

The emissions of anthropogenic carbon dioxide (CO2) are believed make a significant impact on global climate change. Hence, amine chemical absorption technology has been suggested to separate and recover CO2. In this study, reaction rate constants between CO2 and blended amines were determined by measuring their absorption rate for CO2. The experiments were carried out to investigate the characteristics of CO2 absorption by using additional absorbents such as hexamethylenediamine (HMDA), N-methyldiethanolamine (MDEA) or piperazine blended into 2-amino-2-methyl-1-propanol (AMP) in an agitated vessel. The absorption rates of CO2 into aqueous blended amine solutions were measured. Additive concentrations of 1, 3, and 5 wt% were added for each 30 wt% AMP solution. The results showed that the addition of HMDA, MDEA or piperazine into AMP increased the absorption rate as compared to AMP alone. Of these additives, HMDA showed the most enhancement in the reaction rate of AMP. The reaction rate constants of HMDA, MDEA and piperazine blended into AMP at 303–343 K were given by kH = 3.84 × 1010exp(−5361/T), kM = 6.60 × 109exp(−4959/T), and kP = 9.09 × 109exp(−5058/T), respectively.

Sorption of Carbon Dioxide onto Sodium Carbonate

Abstract Sodium carbonate was used as a sorbent to capture CO2 from a gaseous stream of carbon dioxide, nitrogen, and moisture. The breakthrough data of CO2 were measured in a fixed bed to observe the reaction kinetics of CO2‐carbonate reaction. Several models such as the shrinking‐core model, the homogeneous model, and the deactivation model in the non‐catalytic heterogeneous reaction systems were used to explain the kinetics of reaction among CO2, Na2CO3, and moisture using analysis of the experimental breakthrough data. Good agreement of the deactivation model was obtained with the experimental breakthrough data. The sorption rate constant and the deactivation rate constant were evaluated by analysis of the experimental breakthrough data using a nonlinear least squares technique and described as Arrhenius form.

Absorption of Carbon Dioxide into Non-Newtonian Liquid. I. Effect of Viscoelasticity

Carbon dioxide was absorbed into benzene solutions of PB (polybutene) and PIB (polyisobutylene) in an agitated vessel to get the liquid-side volumetric mass transfer coefficient (k L a). The effect of liquid-phase viscosity, pseudoplasticity, and viscoelasticity of the benzene solutions of PB and PIB, and speed and size of impeller on the gas-liquid mass transfer have been investigated. The elastic properties, considered in the form of the Deborah number, were found to decrease the volumetric mass transfer coefficient. On the basis of experimental data of k L a, a dimensionless equation for k L a was proposed by using the Deborah number.

Reaction sintering and microstructural development in the system Al2O3-AlN

Abstract The reaction sintering and microstructural development of alumina with additions of 1–25 mol% AlN have been investigated by heating under 1-atm nitrogen gas at 1600–1800°C. Sintering Al 2 O 3 with 1 mol% AlN addition at 1750°C, resulted in a ceramic with close to theoretical density of α-Al 2 O 3 (3.98 g/cm 3 ). For the different compositions, the sintered densities decreased with increasing AlN content. This trend was attributed to the presence of secondary phases such as AlON(9Al 2 O 3 ·5AlN) and φ(5Al 2 O 3 ·AlN) formed by reacting Al 2 O 3 with AlN. For a given AlN addition, densification increased with sintering temperature, due to Al 2 O 3 and/or AlON grain growth control. The stability of the individual crystalline phases depends on both sintering temperature and batch composition.

Vaporization reduction characteristics of aqueous ammonia solutions by the addition of ethylene glycol, glycerol and glycine to the CO2 absorption process.

Aqueous ammonia (NH3) solution can be used as an alternative absorption for the control of CO2 emitted from flue gases due to its high absorption capacity, fast absorption rate and low corrosion problem. The emission of CO2 from iron and steel plants requires much attention, as they are higher than those emitted from power plants at a single point source. In the present work, low concentration ammonia liquor, 9 wt.%, was used with various additives to obtain the kinetic properties using the blast furnace gas model. Although a solution with a high ammonia concentration enables high CO2 absorption efficiency, ammonium ions are lost as ammonia vapor, resulting in reduced CO2 absorption due to the lower concentration of the ammonia absorbent. To decrease the vaporization of ammonia, ethylene glycol, glycerol and glycine, which contain more than one hydroxyl radical, were chosen. The experiments were conducted at 313 K similar to the CO2 absorption conditions for the blast furnace gas model.

Absorption of Carbon Dioxide into Aqueous Solution of Sodium Glycinate

Abstract Carbon dioxide was absorbed into aqueous solution of sodium glycinate (SG) at different SG concentrations, CO2 partial pressures, and temperatures in the range of 0.5–3.0 kmol/m3, 25–101.3 kPa, and 298–318 K, respectively, using a stirred semi-batch vessel with a planar gas-liquid interface. Both the reaction order and rate constant are determined from gas absorption rates under the fast reaction regime. The reaction was found to be first order with respect to both CO2 and SG. The activation energy for the CO2-SG reaction has been found to be 59.8 kJ/mol. The second-order reaction rate constants were used to obtain the theoretical values of absorption rate based on the film theory.

Adsorption of Carbon Dioxide onto EDA-CP-MS41

Carbon dioxide was adsorbed onto mesoporous adsorbent of ethylene diamine immobilized CP-MCM41 (EDA-CP-MS41), which was synthesized by chloropropyl functionalized MCM-41 (CP-MS41) with ethylene diamine, in a laboratory-scale packed-bed. The adsorber was operated batchwise with the charge of adsorbent in the range of 1–3 g to obtain the breakthrough curves of CO2. Experiments were carried out at different adsorption temperatures (30–50°C) and flow rates of nitrogen (15–60 cm3/min) to investigate the effects of these experimental variables on the breakthrough curves. The deactivation model was tested for these curves by combining the adsorption of CO2 and the deactivation of adsorbent particles. The observed values of the adsorption rate constant and the deactivation rate constant were evaluated through analysis of the experimental breakthrough data using a nonlinear least squares technique. The experimental breakthrough data were fitted very well to the deactivation model than the adsorption isotherm models in the literature.

Chemical kinetics of carbon dioxide with glycidyl methacrylate using immobilized tributylamine supported on poly(styrene-co-vinylbenzyl chloride) as a catalyst

A soluble copolymer-supported catalyst containing pendant tributylammonium chloride was synthesized by the radical copolymerization of p-chloromethylated styrene followed by the addition reaction of the resulting copolymer with tributylamine. The absorption rate of carbon dioxide was measured from the absorption experiment into glycidyl methacrylate (GMA) solutions containing the catalyst in a semi-batch stirred tank with a plane gas–liquid interface at 0.1013 MPa. The reaction rate constants of the reaction between carbon dioxide and GMA were obtained by the analysis of the mass transfer mechanism accompanied by chemical reactions based on the film theory.Solvents such as toluene, N-methyl-2-pirrolidinone, and dimethyl sulfoxide influenced the reaction rate constants. Furthermore, this catalyst was compared to the monomeric tetrabutyl-ammonium chloride under the same reaction conditions.

Absorption characteristics of new solvent based on a blend of AMP and 1,8-diamino-p-menthane for CO2 absorption

Aqueous 1,8-diamino-p-menthane (KIER-C3) and commercially available amine solutions were tested for CO2 absorption. A 2-amino-2-methyl-1-propanol (AMP) solution with an addition of KIER-C3 showed 9.3% and 31.6% higher absorption rate for CO2 than the AMP solution with an addition of monoethanolamine (MEA) and ammonia (NH3), respectively. The reaction rate constant for CO2 absorption by the AMP/KIER-C3 solution was determined by the following equation: k2,AMP/C3 = 7.702 x 10(6) exp (-2248.03/T). A CO2 loading ratio of the AMP/KIER-C3 solution was also 2 and 3.4-times higher than that of the AMP/NH3 solution and the AMP/MEA solution, respectively. Based on the experimental results, KIER-C3 may be used as an excellent additive to increase CO2 absorption capability of AMP.