Mass transfer study

Johnson, A.I. and Chen-Jung Huang, Mass Transfer Studies in an Agitated Vessel, A.I.Ch.E. Jour 2, 1956, p. 412. 

The effective interfacial area is used in mass transfer studies as an undivided part of individual and overall coefficients when it is difficult to separate and determine the effective area. The work of Shulman et.al.,65 presents a well organized evaluation of other work in addition to their own. One of the difficulties in correlating tower packing performance lies in obtaining the correct values for the effective interfacial areas of the packing on which the actual absorption, desorption, chemical reaction, etc. are completed. Figures 9-47 A, B, C, D, E, F, G present a correlation for Avater flow based on the ammonia-water data of Fellinger [27] and are valid for absorption work. 

Two-phase mass transfer and heat transfer without phase change are analogous, and the results of mass-transfer studies can be used to help clarify the heat-transfer problems. Cichy et al. (C5) have formulated basic design equations for isothermal gas-liquid tubular reactors. The authors arranged the common visually defined flow patterns into five basic flow regimes, each... 

The application of Eqs. (17) requires a detailed knowledge of the two-phase hydrodynamics so that the parameters Ru Wc, U,a, U a, Vd, a, and Qt can be evaluated. The fluid dynamics of annular flows have been investigated experimentally. Russell and Lamb (R4) have studied the flow mechanism of horizontal annular flow Cousins et at. (C8) have dealt with droplet movement in vertical annular flow. Anderson and Russell (A6) have analyzed the interchange of droplets in horizontal systems, and numerous other hydrodynamic studies have been reported in Hewitt et al. (HI). Cichy et al. (C4) have reviewed the methods for evaluating the same hydrodynamic parameters that are also used in mass transfer studies. It is difficult to... 

Model Reactions Used in Electrochemical Mass-Transfer Studies... 

Therefore, criteria in the selection of an electrode reaction for mass-transfer studies are (1) sufficient difference between the standard electrode potential of the reaction that serves as a source or sink for mass transport and that of the succeeding reaction (e.g., hydrogen evolution following copper deposition in acidified solution), and (2) a sufficiently low surface overpotential and rate of increase of surface overpotential with current density, so that, as the current is increased, the potential will not reach the level required by the succeeding electrode process (e.g., H2 evolution) before the development of the limiting-current plateau is complete. 

Karamanev, D. G., Nagamune, T., and Endo, I., Hydrodynamic and Mass Transfer Study of a Gas-Liquid-Solid Draft Tube Spouted Bed Bioreactor, Chem. Eng. Sci., 47 3581 (1992)... 

Here Va and are the true velocities at the entrance, of gas and liquid, respectively, and do is the critical droplet diameter. The value of the Wee depends on the degree of shock at the entrance section e.g., for smooth liquid injection, 22 was used, and for tee entrances, 13 to 16. Collier and Hewitt (C6) also measured entrainment in air-water mixtures, and have extended the same correlation to much wider ranges, using We — 13 in the case of jet injection with the results shown in Fig. 9. Anderson et al. (A5), during mass-transfer studies in a water-air-ammonia system, found en-... 

Historically, the alpha factor, a, was developed from oxygen mass transfer studies in the aerated basins of municipal waste water treatment plants. It thus denotes the ratio of the mass transfer coefficient for oxygen measured in the waste water (WW) to that measured in tap water (TP). 

Mass-transfer studies under high pressure are scarce in the open literature for TBR. At present, to our knowledge, only the Twente and Nancy groups have measured the gas-liquid interfacial area concerning TBR operating at elevated pressures. 

Zhavoronkov et al. (Z2), 1951 Mass transfer studies (CO into water film) in two diameters of wetted-wall column and on wetted-plate packing (liquid mixed at intervals). Gas velocity had little effect on transfer rates. 

The rate parameters of importance in the multicomponent rate model are the mass transfer coefficients and surface diffusion coefficients for each solute species. For accurate description of the multicomponent rate kinetics, it is necessary that accurate values are used for these parameters. It was shown by Mathews and Weber (14), that a deviation of 20% in mass transfer coefficients can have significant effects on the predicted adsorption rate profiles. Several mass transfer correlation studies were examined for estimating the mass transfer coefficients (15, jL6,17,18,19). The correlation of Calderbank and Moo-Young (16) based on Kolmogaroff s theory of local isotropic turbulence has a standard deviation of 66%. The slip velocity method of Harriott (17) provides correlation with an average deviation of 39%. Brian and Hales (15) could not obtain super-imposable curves from heat and mass transfer studies, and the mass transfer data was not in agreement with that of Harriott for high Schmidt number values. 

A more detailed mass transfer study on the carbon dioxide absorption in sodium hydroxide solution was performed using a falling-film microreactor [319]. Experimental investigations were made at a liquid flow of 50ml/h, with three NaOH concentrations (0.1,1 and 2 M), at a fixed inlet molar ratio C02 NaOH of 0.4, and for a range of C02 concentration of 0.8-100%. A two-dimensional reactor model was developed, and the results are similar to the experimental data at low NaOH concentrations (0.1 and 1 M). The agreement is less pronounced for higher concentrations such as 2 M NaOH, which could be explained by either maldistribution of... 

First, we measured thermodynamic and mass transfer data of the multicomponent system olive 0U/CO2 (3,4). The phase equilibria was modulated by correlating the partition coefficients (Kj = y /x ) of each component present in the mixture as a function of the mole fraction of the FFA fraction in the liquid phase (3). Mass transfer studies were performed in a lab-scale countercurrent packed column. The experimental measured mass transfer coefficients were... 

Table 9-3 Summary of gas-liquid interface mass transfer studies for cocurrent gas-liquid flow in a fluidized bed...

Vospemik M, Pintar A, Bercic G, and Levee J. Mass transfer studies in gas-liquid-solid membrane contactors. Catal Today 2003 79-80 169-179. 

The chlorination rate was found to be a function of the total copper concentration, cupric/cuprous ratio, and temperature. An empirical expression relating these variables to the space-time yield has been derived. Extensive oxygen mass transfer studies have been carried out in both process and sodium sulfite solutions these taken together make possible the scale-up and design of a commercial reactor with ample safety factor on O2 concentration level. 

This simple flow pattern becomes unstable at higher rotation speeds, and a cellular flow pattern (termed Taylor vortices) is observed. Taylor vortices provide an irregular enhancement to mass transfer. At still higher rotation speeds, the flow becomes fully turbulent. Mass-transfer studies with rotating cylinders are conducted in the turbulent flow regime because the flow provides a uniform enhancement to mass transfer. 

Figure 5.9. Schematic illustration of batch extraction cell used in liquid-liquid mass transfer studies.

Wang, M. L., andH. S. Wu, Kinetic and Mass Transfer Studies of a Sequential Reaction by Phase Transfer Catalysis, CAem. Eng. Sci., 46, 509 (1991). 

Farther away from the surface the fluid velocities, though less than the velocity of the undisturbed fluid, may be fairly large, and flow in this part of the boundary layer may become turbulent. Between the zone of fully developed turbulence and the region of laminar flow is a transition, or buffer, layer of intermediate character. Thus a turbulent boundary layer is considered to consist of three zones the viscous sublayer, the buffer layer, and the turbulent zone. The existence of a completely viscous sublayer is questioned by some, since mass transfer studies suggest that some eddies penetrate all the way through the boundary layer and reach the wall. 

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