Measurement and simulation of mass transfer and backmixing behavior in a gas-liquid helically coiled tubular reactor. (12th October 2017)

• Record Type: Journal Article
• Authors: Jokiel, Michael; Wagner, Lisa-Maria; Mansour, Michael; Kaiser, Nicolas Maximilian; Zähringer, Katharina; Janiga, Gábor; Nigam, Krishna D.P.; Thévenin, Dominique; Sundmacher, Kai
• Is Part Of: Chemical engineering science. Volume 170(2017)
• Page Start: 410
• Page End: 421
• Publication Date: 2017-10-12
• Subjects: Helix reactor -- Two-phase flow -- Mass transfer -- Axial dispersion -- CFD -- Optical measurement; Chemical engineering -- Periodicals; Génie chimique -- Périodiques; Chemical engineering; Periodicals; Electronic journals; 660
• DOI: 10.1016/j.ces.2017.01.027
• Languages: English
• ISSNs: 0009-2509

Abstract

Highlights: Different measurement techniques were used to study the gas-liquid mass transfer. Computational Fluid Dynamics (CFD) was used to model the gas-liquid mass transfer. The results indicate an influence of the coil curvature ratio on the mass transfer. Abstract: Volumetric mass transfer coefficients ( kL a ) and Bodenstein numbers ( Bo ) for the elongated bubble flow regime in horizontal helically-coiled tube reactors are reported using two different measurement techniques (oxygen optodes, and optical observation of an oxygen-sensitive dye). Additionally, the gas-liquid mass transfer and the residence time behavior of the two-phase flow were described with a 3D Computational Fluid Dynamics (CFD) model, and also with a one-dimensional two-phase model. For this study, 16 cases involving different gas and liquid volumetric flow rates were employed to generate air-water flows through two helically coiled tubes with curvature ratios of δ 1 = 0.093 and δ 2 = 0.3, respectively. The superficial gas and liquid Reynolds numbers ( Re s, G and Re s, L ) and the gas hold-up ( ∊ G ) are varied from 494 to 2483, from 1456 to 2713, and from 0.46 to 0.81, respectively. The mass transfer measurements show an increasing gas-liquid mass transfer rate with increasing superficial velocity of the liquid-phase and Re s, G . The Bodenstein number decreases with increasing gas-phase Reynolds number and increases with increasing superficial velocity of the liquid-phase. Correlations describing the mass transfer and backmixing behavior are proposed. The CFD results are in excellent agreement with the experimental data. With the 1D two-phase model it is possible to describe the residence time behavior of the two-phase flow through the helically coiled tube.