Equilibrium Solubility of CO₂ in Aqueous Mixtures of DEA and AEEA

Abstract

The present communication presents the new experimental CO 2 solubility data in an aqueous mixture of diethanolamine (DEA) and (2-aminoethyl)ethanolamine (AEEA) at CO 2 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 CO 2 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 CO 2 concentration in the inlet gas stream. The CO 2 solubility in the amine mixture falls with the rise in temperature but rises with an increase in CO 2 concentration in the inlet gas stream. The highest amount of CO 2 solubility in (DEA + AEEA) mixtures was observed as 0.74 mol CO 2 /mol absorbent with AEEA mole fraction in total amine of 0.2 at a 1.84 mol·kg −1 total concentration of amine mixture and 313.14 K. The result of this work is compared with some of the most studied amine mixtures available in the literature. ■ INTRODUCTIONUninterrupted human activities have resulted in a significant increase of greenhouse gas concentrations in the environment over the past 200 years. By the year 2100, the average worldwide temperature may increase by (1.4 to 5.8)°C due to this increased amount of greenhouse gases as predicted by the various estimations of climate models. 1 The excessive release of greenhouse gases has caused the serious environmental problems like global warming found in nature. CO 2 , amounting an almost more than 50 % major share in greenhouse gases, produces more than 60 % of the increased greenhouse effect at present. CO 2 emissions mostly come from fossil-fuel based industries, 2 such as coal-fired thermal power generation, petroleum and natural gas based energy industries, and various metallurgical processes, responsible for sustainable economic growth. India is the fifth largest CO 2 contributor with approximately 5 % of the worldwide CO 2 emissions, and the increasing emission trend is likely to be continued. The energy scenario of WEO 2009 forecasts that CO 2 emissions in India will be more than 2.5 times that of the 2008 emission level by the year 2030 due to its economic growth. 3 The majority of these emissions is attributed to heat and electricity generation, which showed an enhanced CO 2 emission from 42 % in 1990 to 56 % in 2008. The transport sector contributes the smallest share of about 9 % of CO 2 emissions in 2008 among other sectors. These growing trends of CO 2 emissions raise the issue of low energy use and the need to invent efficient technologies for CO 2 capture from contaminated gas streams released from industrial origins. Chemical absorption is a mature technology and mostly used in postcombustion thermal power plants where the CO 2 concentration is very low (≤ 20 % by volume). This technology still has some limitations such as absorbent degrad...

Numerical Model to Analyze the Physicochemical Mechanisms Involved in CO2 Absorption by an Aqueous Ammonia Droplet

“…Three gas temperatures were represented: 100, 125, and 150 • C. As can be seen, the carbon absorption decreases with the gas temperature due to a reduction in the Henry's constant. Previous works also revealed similar trends using ammonia [8] and other solvents such as DEA and AEEA [41]. Another effect that decreases carbon absorption is evaporation.…”

Role of solvents in CO2 capture processes: The review of selection and design methods

“…AEEA shows proper absorption rate among amines that are added as an activator to the tertiary amines. Further, as it is a Diamine compound, one mole of it is able to absorb 2 moles of CO2, thus has a high absorption capacity for CO2 but it increases the regeneration cost [143]. Zoghi [144] considered five additives and reported that AEEA-MDEA aqueous solution has the highest absorption rate of CO2.…”

Carbon Dioxide Separation from Flue Gases: A Technological Review Emphasizing Reduction in Greenhouse Gas Emissions

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