Calvert equation

Dosing adjustment based on Calvert equation Proportional to lower creatinine clearance, where normal equal to 70 mL/minute (0.67 mL/s x m2)... 

Using the data provided in Problem VEN.4, estimate the pressure drop across the bench-scale unit. Use both the Theodore and Calvert equations. 

Using the Calvert equation to estimate the pressure drop,... 

The Calvert equation significantly underpredicts the pressure drop at low values of R. Note that this equation fails when R is zero. 

As with dust cyclones, no reliable pressure-drop equations exist (see Sec. 17), although many have been published. A part of the problem is that there is no standard cyclone geometry. Calvert (R-12) experimentally obtained AP = 0.000513 J Q /hiWi) 2.8hiWi/dl), where AP is in cm of water Pg is the gas density, g/cm is the gas volumetric flow rate, cmVs hj and Wj are cyclone inlet height and width respectively, cm and is the gas outlet diameter, cm. This equation is in the same form as that proposed by Shepherd and Lapple [Ind. Eng. Chem, 31, 1246 (1940)] but gives only 37 percent as much pressure drop. 

Figure 14-120 presents an early calculated estimate of mesh efficiency as a fraction of mist-particle size. Experiments by Calvert (R-12) confirm the accuracy of the equation of Bradie and Dickson (Joint Symp. Pioc. Inst. Mech. Eng./Yoikshiie Bi Inst. Chem. Eng., 1969, pp. 24-25) for primary efficiency in mesh separators ... 

Pressure drop in a venturi scrubber is controlled by throat velocity. While some venturis have fixed throats, marw are designed with variable louvers to change throat dimensions and control performance for changes in gas flow. Pressure-drop equations have been developed by Calvert (R-13, R-14, R-15), Boll [Ind Eng Chem Fundam, 12, 40 (1973)], and Hesketh [J. Air Pollut Control Assoc, 24, 939 (1974)]. Hollands and Goel [Ind Eng Chem Fundam, 14, 16 (1975)] have developed a generalized pressure-drop equation. 

Calvert (R-15) critiqued the many pressure-drop equations and suggested the following simplified equation as accurate to 10 percent ... 

Calvert et al. []. Air Pollut. Control Assoc., 22, 529 (1972)] obtained an explicit equation by making some simplifying assumptions and incorporating an empirical constant that must be evaluated experimentally the constant may absorb some of the deficiencies in the model. Although other models avoid direct incorporation of empirical constants, use of empirical relationships is necessary to obtain specific-estimates of scrubber collec tion efficiency. One of the areas of greatest uncertainty is the estimation of droplet size. 

The latent heat Of vapcrixati o-f ammonium chloride has been determined experimentally by J. C. G. de Marignae21 at atm press, at 33 0 and 43"8 Cals, per mol. this constant has also been calculated from vap. press, data by A. Horstmann and F. M. G. Johnson using Clausius and Clapeyron s equation Tdp/dTfa— v2). In no case is the evidence that the vapour had assumed the equilibrium conditions satisfactory, and A. Smith and R. H. Lombard also apply Clausius and Clapeyron s equation to the measurements of A. Smith and R. P. Calvert of the sat. vap. press, of ammonium chloride. The value of dp/dT was calculated from their vap. press, equation log p=—ajT- -b log T- -c the volume of the solid v2 is negligibly small, and that of the vapour is equal to the reciprocal of the mol. vapour density 1/D. Substituting these values in Clausius and Clapeyron s equation there results s... 

Calvert found that reentrainment from the baffles was affected by the gas velocity, the liquid-to-gas ratio, and the orientation of the baffles. Horizontal gas flow past vertical baffles provided the best drainage and lowest reentrainment. Safe operating regions with vertical baffles are shown in Fig. 14-112. Horizontal baffles gave the poorest drainage and the highest reentrainment, with inclined baffles intermediate in performance. Equation (14-228), developed by Calvert, predicts pressure drop across zigzag baffles. The indicated summation must be made over the number of rows of baffles present. 

If the quantum yield is not known, which is often the case, it can be set equal to 1 and GC-SOLAR or Equation (11) with Zx becomes a useful screening tool for estimating the maximum (solar noon) value of kPE. If other transformation processes for the same chemical have rate constants larger than the value calculated for kPE with 0 = 1, then photolysis is not likely to be important, because actual values of O are generally less than one and usually less than 0.1 (Calvert and Pitts 1967 Mill and Mabey, 1985 Mill, 1995). 

A constant in Calvert correlation for relating penetration and particle size in wet scrubbers, P, =exp(. 4df) as required by7 equation 26... 

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