Liquid Feed Temperature Research Articles

Theoretical Study of CO2 Absorption into Novel Reactive 1DMA2P Solvent in Split-flow Absorber-stripper Unit: Mass Transfer Performance and Kinetic Analysis

Abstract In the present study, the mass transfer performance of CO2 absorption into 1-dimethylamino-2-propanol (1DMA2P) as a novel amino alcohol solvent has been theoretically investigated in a split-flow absorber-stripper unit. The mass transfer performance has been presented in terms of CO2 absorption flux and overall mass transfer coefficient (KGav) by simultaneous considering of chemical reactions and mass transfer phenomenon. The developed comprehensive mathematical model has been validated based on related experimental data in literature. The impact of main operation parameters including liquid feed temperature, amine concentration, liquid velocity and CO2 loading were evaluated. The presented results indicated that increasing the liquid feed temperature, amine concentration and liquid flow rate improves the overall mass transfer coefficient. Also, the CO2 absorption performance of conventional and alternative amines such as monoethanolamine (MEA), diethanolamine (DEA), triethanolamine (TEA), methyldiethanolamine (MDEA), piperazine (PZ), 4-(diethylamino)-2-butanol (DEAB) and 1DMA2P have been investigated and compared in order to provide guidelines about effective screening of solvents. The modeling results indicated that the KGav for CO2 absorption into different solution can be ranked as follows: PZ>MEA>DEA>DEAB>1DMA2P>MDEA>TEA.

Fast screening of amine/physical solvent systems and mass transfer studies on efficient aqueous hybrid MEA/Sulfolane solution for postcombustion CO2 capture

AbstractBACKGROUNDThe addition of a physical solvent to a traditional chemical absorbent has been shown to improve the absorption and desorption performance of the absorbent system. This type of novel absorbent system combining a single physical solvent with an amine solvent is a promising development in the industrial application of CO2 capture.RESULTSHybrid solutions composed of Monoethanolamine (MEA), a physical solvent, and H2O were comprehensively investigated using the rapid solvent screening apparatus and a VLE apparatus. The results show that 30 wt% MEA with 20 wt% Sulfolane and 50 wt% H2O achieved higher rich loading, strong cyclic CO2 capacity and the highest desorption rate over a wide range of CO2 loadings. Also, the mass transfer performance of CO2 absorption into the 30 wt% MEA and 20 wt% Sulfolane solution was investigated in a lab‐scale random packing column. The effects of liquid flow rate, liquid feed temperature, lean CO2 loading, inert gas flow rate and CO2 partial pressure on the mass transfer performance were evaluated in terms of volumetric overall mass transfer coefficient (KGav). Furthermore, a correlation was developed for CO2 absorption into MEA/Sulfolane solution in a random packing column using semi‐empirical models as functions.CONCLUSIONUnlike for amine solution alone, inert gas flow rate is an indispensable operating parameter in the MEA/Sulfolane system. A mass transfer correlation model was established and holds significance in studying the kinetics of CO2 absorption by a mixture of physical and chemical solvents and for the optimal design of Dixon‐ring random packing columns. © 2019 Society of Chemical Industry

Comprehensive solubility of N2O and mass transfer studies on an effective reactive N,N-dimethylethanolamine (DMEA) solvent for post-combustion CO2 capture

The physical solubility and mass transfer performance of CO2 absorption into aqueous N,N-dimethylethanolamine (DMEA) solution were comprehensively studied in the present work. The physical solubility (Henry’s law constant (He)) was measured using a stirred cell reactor for pure DMEA and aqueous DMEA at temperatures from 293.98 to 333.03 K. Then, the physical solubility of CO2 was obtained based on the “N2O analogy” method. Furthermore, He was correlated successfully by using an empirical polynomial model with an average absolute relative deviation (AARD) of 4.23%. The mass transfer performance was studied in a laboratory scale structured packing absorption column at DMEA concentration of 1–4 kmol/m3, liquid feed temperature of 293.15–333.15 K, liquid flow rate of 3.90–11.7 m3/m2-hr, CO2 partial pressure of 6–20 kPa, lean CO2 loading of 0.050–0.300 mol/mol, over the inert gas flow rate range of 26.11–43.52 kmol/m3-hr. Based on the experimental values of He for CO2 into aqueous DMEA solution, the effect of the gas concentration of A in gas-liquid equilibrium (yA∗) on gas phase volumetric overall mass transfer coefficient (KGav) was considered in this study, but found to be an insignificant influence that can be ignored. Analogously, an attempt to correlate the mass transfer coefficient KGav and outlet concentration of CO2 (yout) using semiempirical models as function of the mentioned operational parameters was conducted. The predictive correlations for KGav and yout of the DMEA-CO2-H2O system in structured packing column are KGav=L0.230.6144aeq-aC/pCO2+0.02327 and lnyout=lnyin-0.77PVGΩL0.230.6144aeq-aC/pCO2+0.02327, with acceptable AARDs of 4.59% and 1.48%, respectively.

Mass transfer performance studies of aqueous blended DEEA-MEA solution using orthogonal array design in a packed column

Abstract The mass transfer performance of CO 2 absorption into blended DEEA/MEA solutions was investigated in a lab-scale absorber packed with Sulzer DX structured packing using a standard orthogonal array with an L 25 (5 6 ) matrix. The volumetric overall mass transfer coefficient (K G a V ) was evaluated at various key operating conditions over a amine concentration range of 2.00–5.00 kmol/m 3 , CO 2 lean loading of 0.15–0.35 mol CO 2 /mol amine, over a wide CO 2 partial pressure range of 6–18 kPa, a liquid feed temperature range of 303.15–343.15 K, with liquid flow rate 3.90–11.70 m 3 /m 2 ·h, and 30.47–47.87 kmol/m 2 ·h inert gas flow rate. The results show that these key operating parameters have significant effects on K G a V . Also, based on orthogonal analysis, it was clear that the order of importance for the contribution to K G a V of the six investigated factors was as follows: CO 2 lean loading > CO 2 partial pressure > Liquid feed temperature > Amine concentration > Liquid flow rate > Inert gas flow rate and the optimization of the experimental combination was B 1 C 1 D 2 A 3 E 3 F 2 .

Mass transfer performance and correlations for CO2 absorption into aqueous blended of DEEA/MEA in a random packed column

The mass transfer performance of CO2 absorption into blended N,N‐diethylethanolamine (DEEA)/ethanolamine (MEA) solutions was investigated using a lab‐scale absorber (H = 1.28 m, D = 28 mm) packed with Dixon ring random packing. The mass transfer coefficient KGav, the unit volume absorption rate Φ, outlet concentration of CO2 (yCO2), and the bottom temperature Tbot of CO2 in aqueous DEEA/MEA solutions were determined over the feed temperature range of 298.15–323.15 K, lean CO2 loading of 0.15–0.31 mol/mol, over a wide range of liquid flow rate of 3.90–9.75 m3/m2‐h, by using inert gas flow rate of 26.11–39.17 kmol/m2‐h and 6–18 kPa CO2 partial pressure. The results show that liquid feed temperature, lean CO2 loading, liquid flow rate, and CO2 partial pressure had significant effect on those parameters. However, the inert gas flow rate had little effect. To allow the mass transfer data to be really utilized, KGav and yout correlations for the prediction of mass transfer performance were proposed and discussed. © 2017 American Institute of Chemical Engineers AIChE J, 63: 3048–3057, 2017

Mass transfer performance of CO2 absorption into aqueous DEEA in packed columns

A bench-scale absorption column packed with high efficiency Sulzer DX-type packing was used to determine the volumetric overall mass transfer coefficient (KGav) for CO2 absorption into an aqueous solution of DEEA. The effects of the main operating parameters, such as liquid feed temperature, DEEA concentration, lean CO2 loading, liquid flow rate, CO2 partial pressure, and inert gas flow rate were examined. The results showed that DEEA concentration, CO2 lean loading, and liquid flow rate had a significant effect on KGav while inert gas flow rate had little effect. In addition, CO2-loaded aqueous DEEA solution was observed to have a higher KGav as compared to that of aqueous MDEA solutions. Also, the performance of CO2 absorption with DEEA in structured packing in terms of KGav and cyclic capacity (Δα) were compared with the performance in a random packing column. The structured packing column performed better than the random packing column. Finally, two experimental KGav correlation models for CO2-DEEA system were proposed and found to be in satisfactory agreement with experimental results with AAD of 8 and 3%, respectively.

Experimental study on mass transfer and prediction using artificial neural network for CO2 absorption into aqueous DETA

The volumetric overall mass transfer coefficient (KGav) for carbon dioxide (CO2) absorption into aqueous diethylenetriamine (DETA) was experimentally determined in an absorption column packed with Sulzer DX-type structured packing over a temperature range of 30–50°C and at atmosphere pressure. The effects of the main operating parameters (i.e., inlet CO2 loading, solvent concentration, liquid flow rate, CO2 partial pressure, inert gas flow rate, and liquid feed temperature) on KGav were investigated. The experimental results showed that KGav was influenced by inlet CO2 loading, solvent concentration, liquid flow rate, CO2 partial pressure, and liquid feed temperature, but the effects of inert gas flow rate were insignificant. In addition, an artificial neural network (ANN) model was designed to predict the mass transfer performance. The main operational and physical parameters were selected as input parameters, while KGav was chosen as an output variable. Comparison between the predicted values from the ANN model and experimental data demonstrated that the ANN model is suitable for predicting the absorption performance of packed columns.

Evaluation of Flavor Release From Spray-Dried Powder by Ramping with Dynamic Vapor Sorption–Gas Chromatography

The ramping method for humidity at constant temperature was used to evaluate the release of D-limonene from spray-dried powder using a handmade dynamic vapor sorption (DVS) instrument. The release fluxes of D-limonene from spray-dried powder at two different liquid feed temperatures, 40 and 80°C, were used to evaluate the flavor release properties of spray-dried powder. The flavor fluxes for 40°C of liquid feed temperature were faster than those for 80°C over the whole humidity range.

Heat transfer in trickle bed column with constant and modulated feed temperature: Experiments and modeling

Heat transfer was investigated in an insulated packed bed column with co-current downflow of gas and liquid under constant and periodically modulated gas–liquid feed temperature. Bed temperatures at three axial positions were assessed at steady state for different insulating systems, different gas and liquid flow rates and system pressure. The experimental profiles recorded were modeled with a dynamic pseudo-homogeneous one parameter model to analyze the effect of operating conditions and to deduce coefficients of overall ( U) and bed to wall ( h W ) heat transfer. It appears that the heat transfer is strongly affected by the system pressure, whereas the liquid flow rate has a smaller influence. The experimental data of h W were correlated with the operating conditions leading to a small average error of 7% in the correlation. Condensation of water vapor occurring in the column seems to contribute to the heat transfer inside the packed bed. Several dynamic experiments modulating the feed temperature were also conducted and described with the help of the dynamic model. Predictions with the fitted values of U were in good agreement with experiments and give confidence to apply this model in the investigation of the catalytic wet air oxidation of phenol over carbon conducted in a trickle bed reactor under temperature feed modulation.

Volatiles loss during atomization in spray drying

AbstractLosses of volatile acetates have been measured in the vicinity of pressure nozzles during spraying of sucrose and maltodextrin solutions. Large losses occur very near the atomizer, where only a small portion of the water has evaporated. The effects of atomizer design, nozzle pressure, sucrose concentration, air flow rate, air temperature and liquid feed temperature have all been measured. Correlation of volatiles loss vs. percent water evaporation accounts for most of the effects of changes in spray pattern and drop size distribution. Individual contributions of gas and liquid phase mass transfer are determined from the relative retentions of acetates of different molecular weight and from the effect of sucrose concentration. In the expanding film at the nozzle, both gas and liquid phase resistances are important, but the losses become entirely liquid phase controlled once drops are formed.

Heat transfer studies in a climbing film evaporator Part II: Heat transfer regions

AbstractThere are three sections in an evaporator tube; liquid heating, foam and climbing film. A technique is presented for estimating the lengths of these three sections and the overall heat transfer coefficients in each of them.The lower the liquid feed temperature, the longer the liquid heating length. The length of the foam section does not depend on the liquid feed temperature. In these studies it was estimated to be more than half the length of the evaporator tube. Only at the higher liquid feed temperatures was a climbing film found to exist.