96/05362 High-pressure mass-transfer coefficients in the liquid phase of the binary systems carbon dioxide-methyl myristate and carbon dioxide-methyl palmitate

Dissolution of single carbon dioxide (CO2) bubbles in a vertical pipe of 25 mm in diameter are measured to examine the effects of the ratio λ of sphere–volume equivalent bubble diameter d to pipe diameter D, liquid Reynolds number ReL and surfactants on mass transfer. The bubble diameter d and Reynolds number ReL are varied from 5.0 to 26 mm (λ = 0.20 − 1.0) and from 0 to 3100, respectively. Millipore water, tap water and water contaminated with Triton X–100 are used for the liquid phase. Mass transfer coefficients kL are evaluated from changes in d. The kL decreases with increasing λ for bubbles in stagnant millipore water because of the decrease in bubble rising velocity due to the wall effect. Measured Sherwood numbers Sh do not depend on ReL because a turbulent fluctuation velocity in bulk liquid flow is much smaller than a relative velocity between a bubble and liquid. The mass transfer correlation for a bubble in a stagnant liquid proposed by Johnson et al. is applicable to a bubble in pipe flow, provided that a correct relative velocity between a bubble and liquid is substituted in the correlation. Due to the retardation of capillary wave, mass transfer coefficients for bubbles in contaminated water becomes smaller than those in millipore and tap waters.

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Effects of Bubble Interactions on Liquid Phase Mass Transfer Coefficients in Three Types of Bubble Columns

JOURNAL OF CHEMICAL ENGINEERING OF JAPAN ◽

10.1252/jcej.12we047 ◽

2012 ◽

Vol 45 ◽

pp. 655-660 ◽

Cited By ~ 2

Author(s):

Katsumi Nakao ◽

Keiji Furumoto ◽

Makoto Yoshimoto

Keyword(s):

Mass Transfer ◽

Liquid Phase ◽

Bubble Columns ◽

Transfer Coefficients ◽

Mass Transfer Coefficients ◽

Liquid Phase Mass Transfer ◽

Bubble Interactions

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Experimental Investigation of Enhanced Absorption of Carbon Dioxide in Diethanolamine in a Microreactor

ASME 2013 11th International Conference on Nanochannels, Microchannels, and Minichannels ◽

10.1115/icnmm2013-73162 ◽

2013 ◽

Cited By ~ 3

Author(s):

Harish Ganapathy ◽

Amir Shooshtari ◽

Serguei Dessiatoun ◽

Mohamed Alshehhi ◽

Michael M. Ohadi

Keyword(s):

Carbon Dioxide ◽

Mass Transfer ◽

Natural Gas ◽

Transfer Coefficient ◽

Mass Transfer Coefficient ◽

Absorption Efficiency ◽

Optimum Operating ◽

Transfer Coefficients ◽

Mass Transfer Coefficients ◽

Liquid Absorption

Natural gas in its originally extracted form comprises carbon dioxide and hydrogen sulfide as small, but non-negligible fractions of its dominant component, methane. Natural gas in the above form is typically subjected to a sweetening process that removes these acid gases. Microscale technologies have the potential to substantially enhance mass transport phenomena on account of their inherently high surface area to volume ratio. The present work reports the mass transfer characteristics during gas-liquid absorption in a microreactor. The absorption of CO2 mixed with N2 into aqueous diethanolamine was investigated in a single straight channel having a hydraulic diameter of 762 micrometer and circular cross-sectional geometry. The performance of the reactor was characterized with respect to the absorption efficiency and mass transfer coefficient. Close to 100% absorption efficiency was obtained under optimum operating conditions. Shorter channel lengths were observed to yield enhanced values of mass transfer coefficient on account of the improved utilization of the liquid reactants’ absorption capacity for a given reactor volume. In comparison to the 0.5 m long channel, the mass transfer coefficients with the 0.3 m and 0.1 m channels were higher on an average by 35.2% and 210%, respectively. Parametric studies investigating the effects of phase superficial velocity, liquid and gas phase concentration were performed. The mass transfer coefficients achieved using the present minichannel reactor were 1–3 orders of magnitude higher than that reported using conventional gas-liquid absorption systems.

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