Diethanolamine solutions

SolubiHty of carbon dioxide in ethanolamines is affected by temperature, amine solution strength, and carbon dioxide partial pressure. Information on the performance of amines is available in the Hterature and from amine manufacturers. Values for the solubiHty of carbon dioxide and hydrogen sulfide mixtures in monoethanolamine and for the solubiHty of carbon dioxide in diethanolamine are given (36,37). SolubiHty of carbon dioxide in monoethanolamine is provided (38). The effects of catalysts have been studied to improve the activity of amines and provide absorption data for carbon dioxide in both mono- and diethanolamine solutions with and without sodium arsenite as a catalyst (39). Absorption kinetics over a range of contact times for carbon dioxide in monoethanolamine have also been investigated (40). 

Cryder and Maloney(40) presented data on the absorption of carbon dioxide in diethanolamine solution, using a 200 mm tower filled with 20 mm rings, and some of their data are shown in Figure 12.14. The coefficient KGa is found to be independent of... 

Figure 12.14. Absorption of carbon dioxide in diethanolamine solutions. Liquid rate = 1.85 kg/m2s...

Pyridine-Diethanolamine Solution Mix 5 mL of diethanolamine with 500 mL of freshly distilled pyridine. 

Abstract—Gas-liquid interfacial areas a and volumetric liquid-side mass-transfer coefficients kLa are experimentally determined in a high pressure trickle-bed reactor up to 3.2 MPa. Fast and slow absorption of carbon dioxide in aqueous and organic diethanolamine solutions are employed as model reactions for the evaluation of a and kLa at high pressure, and various liquid viscosities and packing characteristics. A simple model to estimate a and kLa for the low interaction regime in high pressure trickle-bed reactors is proposed. 

Total Vapor Pressures of Aqueous Diethanolamine Solutions (weight % of amine)... 

Bolling Points and Condensation Temperatures of Aqueous Diethanolamine Solutions at 50 mm Hg Absolute... 

Absorption of Carbon Dioxide into Piperazine Activated Diethanolamine Solutions... 

Absorption of Carbon dioxide Into Piparazine Activated Diethanolamine Solutions 43... 

Supported liquid membranes offer excellent selectivity for use in gas separation. The transport of CO2 through an aqueous diethanolamine solution held within a hollow fibre membrane is modelled in this paper. When compared with flat-sheet models, the results demonstrated that radial geometry has to be taken into account in a hollow fibre model. The model was used to simulate the CO2 separation in membrane contactors and the results were compared with experimental data. The discrepancy between the results and the experimental data is thought to be due to the conditions within the membrane contactors, which are far from ideal. 

Figure 20 Pressure effect on interfacial area at different gas velocities in a bubble column with perforated plate gas distributor (nitrogen-aqueous diethanolamine solution, Da = 8.1 cm). (From Oyevaar et al., 1991.)...

DIETHANOLAMINE. HN(CH CHrOHlj. Laboratory tests showed that alloy 3003 was resistant to diethanolamine at ambient temperature. However, at the boiling temperature and under refluxing conditions diethanolamine caused moderate attack. While aluminum alioy heat exchangers have been used to handle diethanolamine solutions, tests under the anticipated conditions should be made prior to use In service. See also Ref (3) p. 145. 

Diethanolamine solutions find wide use in treating sulfur-bearing gas streams. This is because MEA forms a nonregenerable, stable chemical compound with carbonyl sulfide and carbon disulfide. In the past, usually a 2.5 normal (26 wt %) DEA solution has been used as a solvent for H2S in treating natural gas and refinery gas streams. 

The stripping of diethanolamine solutions is similar to MEA regeneration. In this case, although the heat of reaction of CO2 with DEA is 20% lower than with MEA, the regeneration still requires 1.0 to 1.2 lb of steam per gallon of solvent regenerated. The 2.5-normal solution of DEA typically used requires a higher solvent flow rate for the same acid gas absorption than 3-normal MEA solvent. 

Figure 2-1. High-pressure natural gas-treating plant using diethanolamine solution (S.N.P.A.-DEA process). Courtesy of The Parsons Corp.

Figure 2-6. pH values of aqueous mono- and diethanolamine solutions (technical grade). 

Diethanolamine solutions that are used for treatment of refinery gases typically range in concentration fiom 20 to 25 wt%, while concentrations of 25 to 30 wt% are conunonly used for natural gas purification. Diglycolamine solutions pically contain 40 to 60 wt% amine in water, and MDEA solutiw concentrations may range fiom 35 to 55 wt%. 

Figure 2-30. Vapor pressure of CO2 vs. CO2 conceniration in 5 N diethanolamine solution.

Figure 2-34. Effect of CO2 on vapor pressure of H2S over 2 N diethanolamine solution containing both CO2 and H2S.

University. The results of these studies are presented in a series of research reports. Research reports RR-8S (Christensen et al., 1985), RR-1Q2 (Merkley et al., 1986), and RR-108 (Helton et al., 1987) provide data on CO2 in aqueous diglycolamine, methyldiethanolamine, and diethanolamine solutions, respectively. Reports RR-114 (Van Dam et al., 1988) and RR-127 (Oscarson and Izatt, 1990) give similar data on H2S in diethanolamine and metfayldietfaanol-amine, respectively. 

Helton, R., Christensen, J. J., and Izatt, R. M., 1987, Enthalpies of Solution of CO2 in Aqueous Diethanolamine Solutions, GPA Research RqxMt 108, Project 821, Brigham Young University, Provo, UT, May. 

Kennard, M. L., and Meisen, A., 1984, Solubility of Carbon Dioxide in Aqueous Diethanolamine Solutions at Elevated Temperatures and Pressures, J. Chem. Eng. Data, Vol. 29, pp. 309-312. 

Lawson, J. D and Garst. A. W., 1976, Gas Sweetening Data Equilibrium Solubility of Hydrogen Sulfide and Carbon Dioxide in Aqueous Monoethanolamine and Aqueous Diethanolamine Solutions, J. of Chem. ami Eng. Data, Vol. 21, No. 1, pp. 20-30. 

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