Tracer data, inert

Agreement of the t values calculated by these two methods provides a good check on experimental accuracy. Occasionally, Equation (15.13) is used to determine an unknown volume or an unknown density from inert tracer data. 

In an effort to determine the cause of low yields from a reactor, a tracer study was conducted. An amount m0 = 3.80 kg of an inert tracer A was injected into the feed port of the 1. 9-m3 reactor. The volumetric flow rate was constant at q0 = 3.1 L s-1. The following tracer-response data were acquired ... 

In the most useful form the test consists of a momentary injection of a known amount of inert tracer at the inlet of the operating vessel and monitoring of its concentration at the outlet. The data are used most conveniently in reduced form, as E — C/C0 in terms of tr — t/t, where... 

In practice, the EOF mobility in the bulk electrolyte is estimated from migration data obtained with a suitable neutral and inert tracer in an open tube by using the following expression... 

Use of Inert Tracer Data to Estimate the Course of Reaction in Geometrically Complex Natural Flows... 

These interesting devices consist of a tube or duct within which static elements are installed to promote cross-channel flow. See Figure 8.5 and Section 8.7.2. Static mixers are quite effective in promoting radial mixing in laminar flow, but their geometry is too complex to allow solution of the convective diffusion equation on a routine basis. A review article by Thakur et al. (2003) provides some empirical correlations. The lack of published data prevents a priori designs that utilize static mixers, but the axial dispersion model is a reasonable way to correlate pilot plant data. Chapter 15 shows how Pe can be measured using inert tracers. 

You have designed the following tracer experiment to determine whether your continuous flow reactor for pilot-scale study is perfectly mixed, like an ideal CSTR. At time t = 0, you inject 100 g of an inert tracer into the 100 L reactor after establishing a feed flow rate of 25 L per min. Your technician measures the tracer concentration in the outlet stream for a few minutes and provides you with the following data ... 

Food metabolism and passage-rate studies using the inert tracer Cr have been conducted on the ring-necked pheasant (Phasianus colchicus) by G. E. Duke et al. (1968) wherein the Cr was applied to food. In single-dose studies, the CrCla solution was placed on a food pellet with a pipette. Excreta were counted with a scintillation counting system. Food consumption and total excreta data permitted computation of a metabolism coefficient ... 

Kerekes, 1986), inert tracers (Backlund et al 1987 Robitaille, 1987), and temperature profiling (Torregrossa, 1983 Sinn, 1984 Robitaille, 1987 Rewatkar et al., 2001). Most measnrements have been made on the macroscale (scales > 100 cm ), althongh Paterson and Kerekes (1986) measured mixing quality on a fiber scale. The assessment techniques used are typically tedious, which limits the amount of data that can be collected. The suspension must also be sampled in a manner that avoids farther mixing, which can often be difficult. The use of mixing qnality indices requires that pulp samples be bleached in the laboratory for comparison with mill pulps. 

The volume average of Du calculated is compared with experimental data reported by Cai and Chen [15] for the same tray column under different vapor rates (F factor) as shown in Fig. 4.9. Although the experimental measurement is performed by using inert tracer technique and the comparison is only approximate, it demonstrates that the prediction of Du is feasible by using the method of CMT without doing tedious experimental work. 

Fig. 5.7 Comparisons of experimental data, the simulation by two-equation model and by conventional model for Run T17 (dash dot lines one-dimensional model with mass diffusivity obtained by inert tracer technique, solid curve two-equation model, and circle and square experimental data), a CO2 loading, b Enhancement factor (Reprinted from Ref. [8], Copyright 2006, with permission from Elsevier.)...

In principle there are enough equations and tracers (Ar, N2, He, O2) to solve for all the unknowns two for bubbles imbedded in Faub (Eq. (10.35)), Kz and J. At the time of writing this book it has not been possible to do this in practice at the few locations where it has been tried (the location of the data in Fig. 6.12 is the Hawaii Ocean Time series, HOT), because the inert gas signals are small and can be... 

Marine chemists are presently exploring the use of an extended suite of inert gas tracers to separate the effects of bubbles, gas exchange, temperature change and atmospheric pressure on the degree of gas super saturation. When more high quality data become available for more gases the importance of the different mechanisms will be clearer. 

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