Absorption rates conversion

The liquid holdup of the packing section decreases, which leads to a lower conversion of the kinetically controlled reactions of C02 and a reduction in the C02 absorption rate. As a consequence, the solvent mole fractions of HC()3 and carbamate decreases whereas the relative fraction of HS increases. The selectivity of the absorption process toward the H2S and HCN reduction is enhanced by minimizing the liquid holdup of the column. At the same time, a larger interfacial area improves the performance of the plant. Therefore, modem industrial sour gas scrubbers should be equipped with structured packings. 

A recent study of mass transfer controlled kinetics of propene polymerization by TiCl3/AlEt3 catalyst has shown the monomer absorption rate to be proportional to the speed of stirring and to fall with increase in conversion [289]. 

The most common approach to evaluating the predictability of an IVIVC is depicted in Figure 46.7. The procedure involves the conversion of the in vitro dissolution rate into in vivo absorption rate and then, by the use of convolution methods, a prediction of the plasma concentration-time prohle. This is represented as... 

FIGURE 46.7 Most common approach in evaluating the predictabihty of an IVIVC—the conversion of in vitro dissolution rate into in vivo absorption rate and the prediction of plasma concentration-time profile by the use of deconvolution methods (see Section 46.5). 

Table 1-1. Conversion of Heat Absorption Rates for Tubes Spaced Two Diameters...

A liquid-phase oxidation is carried out in aqueous solution in an agitated, sparged reactor. Batch tests show that the absorption rate decreases as the conversion increases, judging from the change in exit gas composition. The dissolved reactant and the product are nonvolatile, and the vapor pressure of the solution is about 80% that of water. The solution density is 60 Ib/ft. ... 

A partial oxidation is carried out by bubbling oxygen through a solution of reactant B in a stirred reactor. Batch tests show the oxygen absorption rate decreases as the conversion of B increases (Table 7.4). The initial reaction rate divided by the oxygen solubility is less than the value predicted from correlations for though the predicted rate is uncertain by 30%. 

In Equation 3, k Is the sunlight absorption rate summed over all the A s of the sunlight that are absorbed by the pollutant is the sunlight Intensity for a specified wavelength Interval (N) centered at wavelength (A) (units, photons cm" sec" N nm ) j - 6.023 x lO Is a conversion constant that makes the units of Z and e compatible and dr A kave been defined above (Equation 2). The latter two data are measured In the laboratory (cf. Table I and II) while the solar Intensity (Z ) data as functions of time of day, season, and latitude for the range A - 297.5 to 800 nm are available... 

Equations 11.39 (for intravenous holus) and 12.37 are identical hence, they convey the same message. The administration of a smaller dose more frequently will require a greater number of doses to attain a given fraction of steady state (see Table 11.3). Conversely, administration of larger dose less frequently will require fewer doses to attain a given fraction of steady-state condition. Note that Eq. 12.37 is identical to Eq. 11.39 only when the absorption rate constant is much greater than the elimination rate constant and each subsequent dose is administered in the post-absorption phase. 

Metoclopramide speeds up gastric emptying. The relatively poorly soluble ketoprofen spends less time in the stomach where it dissolves, and as a result less is available for absorption in the small intestine. Conversely, the absorption rate of tolfenamic acid is increased, without a change in the extent of absorption. 

Boron compounds have low solubility relative to some cadmium, gadolinium, or europium compounds in nitric acid solutions, and would be more likely to precipitate from solution if high concentrations are required. Cadmium is a desirable poison however, it may be volatile at temperatures encountered in the waste conversion proqess and would therefore require an additional process for recovery. Additional requirements for, soluble poisons Include chemical stability in the solution and processing behavior similar to the fissile material. Each poison s neutron absorption rate is uniquely dependent on the neutron energy spectra of the system hence, the relative neutronic effectiveness of each poison varies from one system to another. Consequently, a mixture of poisons in a solution may be more effective than dither poison alone. ... 

PVC with more rapid plasticizer absorption rate than one prepared with poly(vinyl alcohol) 90% conversion... 

On the basis of the analytical solutions, i.e. eq. (12) incorporating the appropriate expressions for Q, the influence of gas phase mixing on reactor performance can be studied. For a first order reaction it can be shown that the ratio of absorption rates and conversions, respectively, of the mixed (m) and unmixed (p) model is given by... 

Fig. 4 Effect of gas phase mixing on conversion and absorption rate for first order reaction - Comparison of models <11> and <13> both with backmixed liquid phase...

In model <41> and <44> the gas phase concentration is constant as a result of complete mixing in model <41> and due to low conversion and differential reactor behavior in model <44>. In both cases the results of the absorption-reaction theory [19, 20] can be applied directly to calculate absorption rates, space-time-yields and conversion. Therefore, no further treatment is required here. 

Gas phase dispersion Important at high absorption rates and high conversion of gaseous reactant, respectively. Very important, comparable with one-phase reactors... 

---