265556 The Intensification of Mass Transfer of CO2 Bubble Absorption Into Monoethanol Amine (MEA) Aqueous Solution in a Rectangular Microchannel

Wednesday, October 31, 2012
Hall B (Convention Center )
Xiqun Gao1, Chunfang LI2, Taotao Fu2 and Youguang Ma2, (1)Yifang Industry Corporation, Liaohua Petrochemical Fiber Company, Liaoyang , China, (2)State Key Laboratory of Chemical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin, China

The intensification of mass transfer of CO2 bubble absorption into monoethanol amine (MEA) aqueous solution in a rectangular microchannel

Xiqun Gaoa, Chunfang Lib, Taotao Fub, Youguang Mab*

a Yifang Industry Corporation, Liaohua Petrochemical Fiber Company, Liaoyang 111003, P. R. China

b State Key Laboratory of Chemical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, P. R. China

* Corresponding author: ygma@tju.edu.cn

Abstract: This article aims at studying the absorption process of CO2 bubbles in monoethanol amine (MEA) aqueous solutions in microchannels by using a high-speed digital camera. Experiments were conducted in a polymethyl methacrylate (PMMA) rectangular microchannel with 600 µm wide and 400 µm deep. The parameters affecting the bubble length such as the concentration of monoethanol amine (MEA) aqueous solutions, gas and liquid flow rates were studied. The dissolution process of CO2 bubbles in monoethanol amine (MEA) aqueous solutions in microchannels was characterized by the diminishing of the bubble length with time . The results showed that the slug bubble flow was transformed into the bubbly flow with the movement of bubbles in microchannels. The length of the slug bubble reduced exponentially with time to a relative stable length, and then the small bubble dissolved at a quite slow speed. The dissolution speed for the slug bubble decreased with the decrease of the concentration of monoethanol amine (MEA) aqueous solutions and the liquid flow rates, and with the increase of the gas flow rates. The instantaneous mass transfer coefficient on the liquid side was correlated by means of the diminishing speed of the bubble length , based on the mass conservation law for a single bubble. The ratio of interfacial area to volume a was calculated directly from the images for the absorption process of CO2 bubbles in monoethanol amine (MEA) aqueous solutions in microchannels. And a new correlation of volumetric mass transfer coefficient on the liquid side  was proposed by taking into account the influences of the concentration of monoethanol amine (MEA) aqueous solutions, and the gas and liquid flow rates. The results showed that the absorption of CO2 bubbles in monoethanol amine (MEA) aqueous solutions was intensified significantly by the miniaturization of the device.

Keywords: CO2 bubble; dissolution; microchannel; miniaturization; process intensification


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