Heat of Absorption of CO₂ in Phase Change Solvents: 2-(Diethylamino)ethanol and 3-(Methylamino)propylamine

Abstract

Heat of absorption of CO 2 in phase change solvents containing 2-(diethylamino)ethanol (DEEA) and 3-(methylamino)propylamine (MAPA) were measured as a function of CO 2 loading at different temperatures using a commercially available reaction calorimeter. The tested systems were aqueous single amines (5M DEEA, 2M MAPA and 1M MAPA) and aqueous amine mixtures (5M DEEA + 2M MAPA and 5M DEEA + 1M MAPA) which give two liquid phases on reacting with CO 2 . All parallel experiments have shown good repeatability. The measurements were taken isothermally at three temperatures in the industrially important temperature range of 40-120 o C. The measured differential heat of absorption values were converted into integral values by integration. Heats of absorption of CO 2 in aqueous single amines were affected by changing the solvent composition (large difference in concentrations) and CO 2 feed pressure simultaneously. In addition to these two parameters, it also depends on temperature and the type of amine used. Tertiary alkanolamine (DEEA) has shown greater dependency on these parameters compared to the diamine (MAPA) containing both primary and secondary amine functional groups. In aqueous amine mixtures, heats of absorption depend on CO 2 loading, temperature and composition of the constituent amines in the mixture. All measured heat of absorption data were compared with 30 mass% MEA used as a base case.

Recent progress and new developments in post-combustion carbon-capture technology with amine based solvents

“…Studies have found that the 5 M DEEA/2 M MAPA possesses a reasonably fast absorption rate and easy stripping of CO 2 (Arshad et al, 2013;Pinto et al, 2014a). It enables CO 2 stripping at either elevated pressure or lower temperature compared with traditional 30 wt% MEA, resulting in reduced energy consumption for regeneration.…”

Vapour-liquid equilibrium study of tertiary amines, single and in blend with 3-(methylamino)propylamine, for post-combustion CO2 capture

“…VLE data over a wide range of temperatures, pressures and concentrations are essential for the process design, optimisation and simulation of the CO2 capture plant, and to make a proper choice of absorbent. cyclic capacity ¼ a rich ðT ¼ 313 K; PCO2 ¼ 9:5 kPaÞ a lean ðT ¼ 393 K; PCO2 ¼ 20:0 kPaÞ ð3Þ A blended amine solvent which has been extensively studied on lab-scale and tested in a pilot plant campaign is the aqueous solution of 2-(diethylamino)ethanol (DEEA) and 3-(methylamino) propylamine (MAPA) [19][20][21][22][23][24]. DEEA has been used because of its low heat of absorption and MAPA because of its fast reaction rate with CO2.…”

Screening and evaluation of novel biphasic solvents for energy-efficient post-combustion CO2 capture

“…The energy use for the CO 2 stripping process generally consists of three elements, heat of reaction, sensible heat, and stripping heat. Compared with the conventional MEA process, the heat of absorption of the TETA + DEEA solvent was approximately 15% lower [assuming the heat of reaction comparable to that of 2 M 3-(methylamino) propylamine (MAPA) + 5 M DEEA reported by Arshad et al (2013)], the sensible heat was 50% lower (due to a significantly reduced mass flow of the enriched phase used for CO 2 stripping), and the stripping heat was 30% lower (based on a product gas stream of CO 2 and water vapor at a 2:1 ratio exiting the stripper as conservatively estimated) considering a stripping temperature of 120 • C. Overall, the total energy saving compared with MEA was estimated to be greater than 30%. As indicated in Table 1 and in the absorption study, TETA + DEEA also showed relatively low viscosity, low volatility, and a low risk of precipitation and low tendency to foam.…”