Capacity, coefficients

Superficial vapor mass flux, Ib/s fr k Capacity coefficient... 

C capacity, coefficient of discharge, concentration d diameter (throat)... 

Hall, H. T. Jr 255 heat, calculation of in First law of thermodynamics 48-56 relationships between variables 52-6 heat capacity coefficients 50-1... 

Note that in this case, the gas phase concentration, Cq, relates to the total mixed gas phase volume Vq, whereas the mass transfer capacity coefficient term is more conveniently related to the liquid volume, Vl-... 

The above model of settler flow behaviour, combined with entrainment backmixing was used by Aly (1972) to model the unsteady-state extraction of copper from aqueous solution, using Alamine 336 solvent. An identification procedure for the relevant flow parameters showed an excellent fit to the experimental data with very realistic entrainment backmixing factors, fL = fQ = 3.5 percent, the fraction of well-mixed flow in the settlers, (XX = ay = 5 percent and an overall mass transfer capacity coefficient, Ka = 25 s->. 

Solution of the required column height is achieved by integrating the two component balance equations and the heat balance equation, down the column from the known conditions Xi , yout and TLin, until the condition that either Y is greater than or X is greater than Xqui is achieved. In this solution approach, variations in the overall mass transfer capacity coefficient both with respect to temperature and to concentration, if known, can also be included in the model as required. The solution procedure is illustrated by the simulation example AMMON AB. 

Klx a is the overall mass transfer capacity coefficient based on the aqueous phase mole ratio X (kmol/m s)... 

Note that the above formulation includes allowance for the fractional phase holdup volumes, hL and ho, the phase flow rates, L and G, the diffusion coefficients Dl and Dq, and the overall mass transfer capacity coefficient Klx a, all to vary with position along the extractor. 

Heat transfer capacity coefficient Exothermic heat of reaction Feed temperature Reactor temperature Concentration Collision frequency Activation energy Gas constant... 

Specific heat Molar flow of inert air Equilibrium constant Overall mass transfer capacity coefficient base on the gas phase Molar flow of solute-free water Pressure Density... 

The component specific heat capacity coefficients, A, B, C, D, are stored as a matrix. If an energy balance is to be made on several units, the specific heat coefficients for all the components can be entered at the start, and the program rerun for each unit. 

Repeat the calculation in Exercise 8 for equilibrium conversion and equilibrium concentration, but taking into account variation of AH° with temperature. Again assume ideal gas behavior. Heat capacity coefficients for Equation 6.42 are given in Table 6.196. 

Kopp A., Class H., et al. Investigation on C02 storage capacity in saline aquifers-Part 2 Estimation of storage capacity coefficient. 2009 International Journal of Greenhouse Gas Control, 3 277-287. 

Table 8.2. Debye temperature ( p in K) and electronic heat capacity coefficient (see Section 8.4) (yin mJ K-1 mol-1) of the elements.

Figure 8.22 Variation of the electronic heat capacity coefficient with composition for the alloys Rh-Pdand Pd-Ag [17]. Solid and dotted lines represent the electronic DoS for the 5s and 4d bands, respectively.

Since the mass transfer coefficient, k, and the specific interfacial area, a, vary in a similar manner, dependent upon the hydrodynamic conditions and system physical properties, they are frequently combined and referred to as a ka value or more properly as a mass transfer capacity coefficient. 

The modelling approach to multistage countercurrent equilibrium extraction cascades, based on a mass transfer rate term as shown in Section 1.4, can therefore usefully be applied to such types of extractor column. The magnitude of the mass transfer capacity coefficient term, now used in the model equations, must however be a realistic value corresponding to the hydrodynamic conditions, actually existing within the column and, of course, will be substantially less than that leading to an equilibrium condition. 

Program GASLIQ1 simulates the case of the full bubble column and program GASLIQ2 that of the full circulation case. For simplicity a constant value of overall mass transfer capacity coefficient, KLa, is assumed to apply for all the liquid regions, but the value obtained in the case of full circulation is taken as five times that for the bubble column. 

Change the value of the mass transfer capacity coefficient KLa and observe how this affects the time to reach equilibrium. Is there a relationship between KLa and the system time constant r ... 

Observe the influence of the mass transfer capacity coefficients KLAa and KLBa on the system dynamics and on the final approach to equilibrium. 

As in example EQEX, the mass transfer capacity coefficient KLa may be set high to obtain near equilibrium stage conditions. 

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