Aqueous Mixtures Of Diethanolamine Research Articles

Equilibrium Solubility of CO2 in Aqueous Mixtures of DEA and AEEA

The present communication presents the new experimental CO2 solubility data in an aqueous mixture of diethanolamine (DEA) and (2-aminoethyl)ethanolamine (AEEA) at CO2 concentrations in the inlet gas stream from (10.13 to 20.27) kPa and temperatures from (303.14 to 333.14) K. The aqueous (DEA + AEEA) mixtures of total concentrations were chosen from (0.92 to 3.22) mol·kg–1, and the mole fraction of AEEA in total amine was varied from 0.02 to 0.20. The findings point that the CO2 solubility in a fixed total concentration of amine mixture becomes more at a higher AEEA mole fraction in total amine with a constant temperature and CO2 concentration in the inlet gas stream. The CO2 solubility in the amine mixture falls with the rise in temperature but rises with an increase in CO2 concentration in the inlet gas stream. The highest amount of CO2 solubility in (DEA + AEEA) mixtures was observed as 0.74 mol CO2/mol absorbent with AEEA mole fraction in total amine of 0.2 at a 1.84 mol·kg–1 total concentration of ami...

Liquid Heat Capacity of Aqueous Solutions Containing Diethanolamine and 2-Piperidineethanol

Liquid heat capacities of aqueous mixtures of diethanolamine (DEA) with 2-piperidineethanol (2-PE) were measured over the temperature range of 303.2 to 353.2 K with a differential scanning calorimeter. For mole fractions of water ranging from 0.2 to 0.8, 16 concentrations of the DEA + 2-PE + water systems were studied. For binary systems, heat capacities of the nine concentrations of DEA + 2-PE were also studied. A Redlich–Kister-type equation for representing excess molar heat capacity was applied to correlate the measured Cp of aqueous alkanolamine solutions. For a total of 176 data points for the DEA + 2-PE + water system, the overall average absolute percent deviation of the calculations were 10.6% and 0.1% for the excess molar heat capacity and the molar heat capacity, respectively. The heat capacities of aqueous mixtures of DEA with 2-PE presented in this study are, in general, of sufficient accuracy for most engineering-design calculations.

Liquid Density of Aqueous Blended Alkanolamines and N-Methylpyrrolidone as a Function of Concentration and Temperature

Experimental values of the liquid density have been determined for ternary systems formed by aqueous mixtures of diethanolamine (DEA) + methyldiethanolamine (MDEA), DEA + 2-amino-2-methy-l-propanol (AMP), DEA + 2-piperidineethanol (2PE), DEA + N-methylpyrrolidone (NMP), MDEA + AMP, MDEA + 2PE, MDEA + NMP, and NMP + AMP. The data were obtained at (313.15, 323.15, and 333.15) K, the total concentration of the blended solvents studied was in the range 30−60 mass %, and for each concentration at least seven points were obtained with different proportions of each solvent. The estimated accuracy of the data is ±0.0004 g·cm-3. From the density data, molar excess volumes were derived, which were correlated using the Redlich−Kister equation; the final expression includes the functionality of both concentration and temperature.

Absorption of Carbon Dioxide into Aqueous Blends of Diethanolamine and Methyldiethanolamine

In this work, a comprehensive model is developed for the absorption of carbon dioxide into aqueous mixtures of primary or secondary alkanolamines with tertiary alkanolamines. The model, which is based on penetration theory, incorporates an extensive set of important reversible reactions and takes into account the coupling between chemical equilibrium, mass transfer, and chemical kinetics. The reaction between CO2 and the primary or secondary amine is modeled according to the zwitterion mechanism. The key physicochemical properties that are needed for the model are the CO2 physical solubility, the CO2 and amine diffusion coefficients, and the reaction rate coefficients and equilibrium constants. Data for carbon dioxide absorption into aqueous mixtures of diethanolamine and methyldiethanolamine are compared to model predictions.

Solubility of CO 2 in aqueous mixtures of diethanolamine with methyldiethanolamine and 2-amino-2-methyl-1-propanol

Using the static method with recirculation of the vapor phase, experimental data for the solubility of CO 2 in aqueous mixtures of known composition of diethanolamine (DEA) with methyldiethanolamine (MDEA) and DEA with 2-amino-2-methyl-1-propanol (AMP) have been obtained in the CO 2 partial pressure range 3–3000 kPa. The data for DEA–MDEA solutions were obtained at 313.15 K and are reported at four different compositions: 10 wt.% DEA–15 wt.% MDEA, 10 wt.% DEA–20 wt.% MDEA, 20 wt.% DEA–10 wt.% MDEA and 10 wt.% DEA–35 wt.% MDEA, data for the solution of 10 wt.% DEA–20 wt.% MDEA were also obtained at 393.15 K. The data for DEA–AMP solutions were obtained at 313.15 and 373.15 K and are reported at two different compositions: 25 wt.% DEA–5 wt.% AMP and 20 wt.% DEA–10 wt.% AMP. The results are given as the partial pressure ( p) of CO 2 against its mole ratio α (mol CO 2/mol alkanolamine), in the range of temperature studied. The solubility of CO 2 in all the studied systems decreases with an increase in temperature and increases with an increase in the partial pressure of CO 2, at a given temperature, and it is a strong function of the composition of the blend of alkanolamines in solution. The aqueous mixture with 10 wt.% AMP, at 313.15 K, shows higher capacity to absorb CO 2 than any of the other mixtures studied here. From the experimental solubility results, exothermic values of the enthalpy of solution, Δ H s, were derived.

FTIR method for VLE measurements of acid‐gas–alkanolamine systems

AbstractThe standard industrial process for the purification of natural gas is to remove acid gases, mainly hydrogen sulfide and carbon dioxide, by the absorption and reaction of these gases with alkanolamines, but the lack of reliable and accurate vapor‐liquid equilibrium (VLE) data impedes the commercial application of more efficient alkanolamine systems. The objective of this research was to develop an FTIR apparatus and an in‐situ technique capable of making VLE measurements of acid‐gas–aqueous alkanolamine systems and to improve the accuracy of vapor–liquid equilibrium measurements at low hydrogen sulfide and carbon dioxide concentrations. The new FTIR apparatus and technique were tested in VLE measurements of low concentrations of carbon dioxide and hydrogen sulfide in aqueous mixtures of diethanolamine.