Liquid-film mass transfer coefficient

Liquid film mass transfer coefficient ( b moles) (cu ft)/(sec) (sq ft) (lb mole)... 

The liquid-film mass transfer coefficient may be given as a correlation for kA( (k, in general for species i, or often denoted simply by kL), or for kAta, the product of the mass transfer coefficient and the interfacial area based on vessel volume (often denoted simply as kLa). 

What is the significance of the parameter fi = (k2C BLDAf5 / kL in the choice and the mechanism of operation of a reactor for carrying out a second-order reaction, rate constant k2, between a gas A and a second reactant B of concentration CBL in a liquid In this expression, DA is the diffusivity of A in the liquid and kL is the liquid-film mass transfer coefficient. What is the reaction factor and how is it related to /l ... 

Molstad, M. C., McKinney, J. F. and Abbey, R. G. Trans. Am. Inst. Chem. Eng. 39 (1943) 605. Performance of drip-point grid tower packings, III. Gas-film mass transfer coefficients additional liquid-film mass transfer coefficients. 

The following one gives the best prediction of the individual liquid-film mass transfer coefficient in water-treatment situations (Chem and Chien, 2002) ... 

The statement cA = c0/ (1 + K) in Eqs. (157a and b) above is tantamount to saying that cA + cB = Co, where c0 is the total concentration of both species of the dissolved solute. If the diffusivities SDA8 and DBs are assumed to be equal, then cB can be eliminated from Eqs. (155) and (156) and a fourth-order, linear partial-differential equation is obtained. The solution of this equation consistent with the conditions in Eq. (157) is obtainable by Laplace transform techniques (S9). Sherwood and Pigford discuss the results in terms of the behavior of the liquid-film mass transfer coefficient. 

A gas component A in air is absorbed into water at latm and 20 °C. The Henry s law constant of A for this system is 1.67 X 10 Pa m kmol h The liquid film mass transfer coefficient and gas film coefficient I(q are 2.50x10 and 3.00 X10" ms respectively, (i) Determine the overall coefficient of gas-liquid mass transfer (ms ). (ii) When the bulk concentrations of A in the gas phase and liquid phase are 1.013 X 10 Pa and 2.00 kmol m , respectively, calculate the molar flux of A. 

Ammonia in air is adsorbed into water at 20 °C. The liquid film mass transfer coefficient and the overall coefficient are 1.44 X 10 and 2.70 X 10 m s , respectively. Use the partition coefficient given in Example 6.2. Determine... 

A buffer solution containing urea flows along one side of a flat membrane and the same buffer solution without urea flows along the other side of the membrane, at an equal flow rate. At different flow rates the overall mass transfer coefficients were obtained as shown in Table P8.1. When the liquid film mass transfer coefficients of both sides increase by one-third power ofthe averaged flow rate, estimate the diffusive membrane permeability. 

From the data shown in Figure 8.4 estimate the liquid film mass transfer coefficient of serum protein at each shear rate and compare the dependence on the shear rate with Equation 8.6. 

Determine the saturated albumin concentration at the gel-layer surface and the liquid film mass transfer coefficient. 

Thus, when deahng with gas transfer in aerobic fermentors, it is important to consider only the resistance at the gas-liquid interface, usually at the surface of gas bubbles. As the solubihty of oxygen in water is relatively low (cf. Section 6.2 and Table 6.1), we can neglect the gas-phase resistance when dealing with oxygen absorption into the aqueous media, and consider only the liquid film mass transfer coefficient Aj and the volumetric coefficient k a, which are practically equal to and K a, respectively. Although carbon dioxide is considerably more soluble in water than oxygen, we can also consider that the liquid film resistance will control the rate of carbon dioxide desorption from the aqueous media. 

This equation can be written Nco,s k[CCor where k[ = VA, Deo, and may be regarded as a liquid-film mass transfer coefficient enhanced oy the fast chemical reaction. This is very convenient because it allows us to use the expression in Volume 2, Chapter 12 for combining liquid-film and gas-film coefficients to give an overall gas-film coefficient ... 

Fig. 4. Liquid film mass transfer coefficient measured by pure oxygen absorption vs. total power dissipated in the liquid, e. Symbols and lines (see Table 1).

C concentration in liquid phase, mol/cur liquid C for concentration at equilibrium with the gas, mol/cm liquid k. liquid film mass transfer coefficient, cur liquid/cm2 bubble... 

Hence, the overall resistance to the mass transfer predicted by this variant of the BAMcomb model is the sum of the resistance in the liquid film and the resistance in the pore fluid. The value of the liquid film mass transfer coefficient Kf can be calculated from literature correlations,400,407,408 while the method for the estimation of the apparent pore liquid mass transfer coefficient Kp can be derived from Eq. (163). The surface interaction between the protein and the immobilized ligand at the internal particle surface can be treated in the same way as for nonporous particles, i.e.,... 

Here, II,L is the hydrogen solubility, which is assumed to remain essentially constant along the entire length of the reactor. The quantity r.V is the open volume of the reactor, A is the transverse cross-sectional area for the hydrogen transfer (as shown in Fig. 7-32), k, is the liquid-film mass-transfer coefficient at the gas -liquid interface, and a is the gas-liquid interfacial area per unit volume of the open space in the reactor. In a physical sense, Eq. (7-39) equates the mass transfer from the gas into the liquid phase with the mass transfer at the surface of the catalyst tube. The constant C, in Eq. (7-39) is obtained, by using the condition (7-40), as... 

Shulman et al.50 measured the gas- and liquid-film mass-transfer coefficients for Raschig rings and Berl saddles. For these types of packings, they presented the correlation... 

---