Radioactive Tracing As Aid for Diagnosing Chemical Reactors

Blet, V.; Berne, P.; Legoupil, Samuel; Vitart, X.

doi:10.2516/ogst:2000010

Cited by 18 publications

(5 citation statements)

References 9 publications

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“…The choice of the tracer depends on the analysis method. The main methods for liquid phase tracing are given below: -Radioactivity (Kolar et al, 1987;Blet et al, 2000;Lelinski et al, 2002;Borroto et al, 2003): the main advantage of radioactivity measurements are the good accuracy (high detection sensitivity) and the fast response time of the sensors. However, this method is not-frequently used in liquid phase tracing due to the price of radioactive tracers and the risk of contamination and irradiation.…”

Section: Experimental Methodsmentioning

confidence: 99%

A new numerical method for axial dispersion characterization in microreactors

Moreau¹,

Raimondi²,

Sauze³

et al. 2017

Chemical Engineering Science

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new numerical method for axial dispersion characterization in microreactors.(2017) Chemical Engineering Science, vol. 168. pp. 178-188. ISSN 0009-2509 Open Archive TOULOUSE Archive Ouverte (OATAO) OATAO is an open access repository that collects the work of Toulouse researchers and makes it freely available over the web where possible. h i g h l i g h t sAn innovative numerical method for axial dispersion characterization is proposed. The method is validated thanks to a RTD experiment in a microchannel. The method is applied to rectangular millimetric wavy channels. The impact of the channel geometry on the axial dispersion coefficient is studied. Keywords:Axial dispersion Numerical method CFD simulations Microreactor Wavy channel a s t r a c t Axial dispersion is a key phenomenon in reactor engineering that can affect yield and selectivity when reactions are carried out. Therefore its characterization is necessary for an adequate modelling of the reactor. The development of compact reactors to fit with process intensification expectations requires the use of characterization methods adapted to small-scale devices. An original method not-frequently used up to now for the estimation of axial dispersion coefficients is presented and applied to millimetric wavy channels. It is based on CFD simulations to calculate velocity and concentration fields from which axial dispersion coefficient can be estimated. This method is used to predict the impact of the wavy channel geometry and of the fluid velocity on axial dispersion in laminar flow regime. The investigated geometrical parameters are the hydraulic diameter (2-4 mm), the cross-sectional aspect ratio defined as the ratio between the channel width and its depth (0.25-1) and the internal curvature radius of the bends (2-3.4 mm). The range of Reynolds number considered is Re = 70-1 600. Axial dispersion coefficient increases with velocity, values range from 2.8 Á 10 À4 to 3.2 Á 10 À3 m 2 Ás À1. It appears that axial dispersion varies slightly in function of the channel hydraulic diameter. Square wavy channels generate less axial dispersion than rectangular wavy ones. Finally, axial dispersion coefficient increases with the internal curvature radius which shows the positive impact of sharp bends to reduce axial dispersion effect.

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Section: Experimental Methodsmentioning

confidence: 99%

A new numerical method for axial dispersion characterization in microreactors

Moreau¹,

Raimondi²,

Sauze³

et al. 2017

Chemical Engineering Science

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“…Examples of the successful adoption of this approach include 32 Si (half-life of 133 ± 9 a [45]), 44 Ti (half-life of 54.2 ± 2.1 a [46]), 60 Fe (half-life of (1.5 ± 0.3) ×10 6 a [47]), 126 Sn (half-life of (2.07 ± 0.21) ×10 +5 a [48,49] and (2.35 ± 0.07) ×10 +5 a [50]). Similar studies have also been carried out by a combination of inductively-coupled plasma mass spectrometry (ICP-MS) and specific activity measurements to determine the half-lives of 79 Se (half-life of (3.77 ± 0.19) × 10 +5 a [51]) and 126 Sn (half-life of (2.33 ± 0.10) × 10 +5 a [52] and (1.98 ± 0.06) × 10 +5 a [53]). Further mass-spectrometric studies should be encouraged to address existing anomalies and uncertainties that remain in half-life values for long-lived radionuclides of recognised importance (i.e.…”

Section: Specific Activity and Mass Spectrometrymentioning

confidence: 99%

“…Obvious care has to be taken to adopt radiotracers that permit the phenomena of interest to be successfully monitored (e.g. by means of γ -ray spectroscopy), with decay-data parameters defined sufficiently well that they do not hinder accurate studies of the chemical reactions and transport mechanisms of interest [125][126][127].…”

Section: Other Industrial and Research Applicationsmentioning

confidence: 99%

Radioactive decay data: powerful aids in medical diagnosis and therapy, analytical science and other applications

Nichols

2012

Radiochimica Acta

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Summary. Decay data are commonly used to characterise and quantify radioactive material, and provide an important means of understanding the properties and structure of the nucleus. Experimental measurement techniques are reviewed, with the emphasis placed on recent developments that represent a potential quantum leap in advancing our knowledge, particularly by means of γ -ray spectroscopy. A select number of internationally-accepted decay-data evaluations and compilations are also discussed in terms of their contents. Both energy and non-energy related applications require the input of well-defined decay data, and such activities have been reviewed. Various important decay-data issues are assessed, and note taken of any significant requirements for better quantified data.

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“…In addition to this, RTD is also used to improve the design of the existing industrial systems; to optimize design of new systems at the design stage itself. Radiotracer techniques are widely used for measurement of RTD in full-scale as well as pilotscale industrial systems because of their specific advantages over conventional tracers (Charlton, 1986;IAEA, 1990IAEA, , 2004Thyn et al, 2000;Blet, 2000;Pant et al, 2000Pant et al, , 2001Pant et al, , 2009aPant et al, , 2009b, 2015, Pant and Yelgoankar, 2002Borroto, 2003 Dagadu et al, 2012). This paper discusses measurements of RTD of liquid phase in a pilot-scale boron poison tank using the radiotracer technique.…”

Section: Introductionmentioning

confidence: 98%