Tracer experiments and RTD's in heterogeneous reactor analysis and design

Shinnar, Reuel; Rumschitzki, David S.

doi:10.1002/aic.690351009

Cited by 17 publications

(7 citation statements)

References 12 publications

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“…(2a) becomes immediate ifr only depends on C. This assumption is due to the fact that an expression for the rate of a catalytic reaction can be given as a function of the sole mobile fluid phase concentration (Wei, 1962;Shinnar and Rumschitzki, 1989). Then, Eq.…”

Section: Contact Time Distribution Theoriesmentioning

confidence: 97%

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A new technique for the determination of contact time distribution (CTD) from tracers experiments in heterogeneous systems

Tayakout‐Fayolle

Othman

Jallut

2005

Chemical Engineering Science

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Section: Contact Time Distribution Theoriesmentioning

confidence: 97%

“…In the case of two phases isothermal reactors, one is interested in extending the approach (Shinnar and Rumschitzki, 1989;Rumschitzki, 1992) by defining a suitable time distribution so that an equation similar to Eq. (1) can be applied.…”

Section: Introductionmentioning

confidence: 99%

A new technique for the determination of contact time distribution (CTD) from tracers experiments in heterogeneous systems

Tayakout‐Fayolle

Othman

Jallut

2005

Chemical Engineering Science

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“…This theory has been extended to multiphase systems (Krambeck et al, 1969;Shinnar and Rumschitzki, 1989). A reverse osmosis module contains a liquid phase and a solid phase (the membrane).…”

Section: The Concept Of Residence Time Distribution (Rtd)mentioning

confidence: 99%

“…The concept of residence time distribution (RTD) has largely been used in reactor design, analysis and diagnostics (Leclerc et al, 1995). This theory has been extended to multiphase systems (Krambeck et al, 1969;Shinnar and Rumschitzki, 1989). A reverse osmosis module contains a liquid phase and a solid phase (the membrane).…”

Section: The Concept Of Residence Time Distribution (Rtd)mentioning

confidence: 99%

Spiral Wound Reverse Osmosis Modules Decomposition into Elementary Units by Analyzing Stimulus Response Experiments: Characterization of the Solute Transfer across the Membrane

2003

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TheoryThere are two approaches for flow modelling: the momentum equations deriving from Navier -Stokes equations and the global method issued from the exploitation of the tracing experiments (Danckwerts, 1953). The first one needs a tedious, finite-elements numerical resolution to obtain the flow pattern in each point of the device. It is difficult to conduct this methodology on the spiral wound reverse osmosis geometry. The second method splits up the device into a small number of well-known reactor flows (perfectly mixing cells, plug flow, dispersed plug flow) according to the device geometry (Leclerc et al., 1995).

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“…The detailed approach used is described in Shinnar and Rumschitzki (1989) and Shinnar, Naor and Katz (1972). Consider a packed bed or…”

Section: Tracer Experiments In Heterogeneous Reactorsmentioning

confidence: 99%

Residence-Time Distributions and Tracer Experiments in Chemical Reactor Design: The Power and Usefulness of a "Wrong" Concept

Shinnar¹

1993

Reviews in Chemical Engineering

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Since its introduction into chemical engineering by Danckwerts(1953), the concept of a residence-time distribution has become an important tool in the analysis of chemical reactors. It is discussed prominently in most textbooks on chemical reactor design, and my previous works discuss its implications and uses. My own work on reaction engineering and process control includes some key ideas from my involvement with residence-time distributions. But there are some basic problems in applying this concept directly to heterogeneous catalytic reactors, which are the mainstream industrial reactors in the petrochemical and oil industries. Residence-time distributions do not apply to catalytic reactors in a conventional sense, so it is time to re-evaluate how we use them in teaching students about reactor design. Following I will review the development of these concepts and the lessons they teach us about chemical reactor design. This unconventional review is influenced by the development of my own ideas on the subject Therefore, I will supply an outline for those readers interested in different aspects of the subject 97 Brought to you by | Purdue University Libraries In Section II are some basic concepts and underlying assumptions needed for discussion. A detailed review of the conventional use of residence-time distribution appears in Shinnar (1987). Here Section II explains why the concepts fail to apply to catalytic reactors. Section ΠΙ discusses intensity function and how to perform useful tracer experiments in catalytic reactors despite the nonapplicability of residence-time distributions. Section IV deals with first-order reactions in homogeneous reactors (readers familiar with this section can skip it). Section V extends some results of first-order reactions to nonlinear reactions and defines the concepts of averageable and nonaverageable reactions, which are useful in defining the minimum information needed for reliable scale-up in nonlinear reactions. Section VI deals with Zwietering's concept of bonding and extends it to reactor design. Section VI also discusses model uncertainty and the minimum information required for design. Section VII reviews theory of tracer experiments in heterogeneous systems. Section VIII reviews the use of these results to define a modified residence-time distribution for packed-bed reactors and use of tracer experiments to diagnose different packed-bed reactors. Section IX extends this to nonlinear reactors in packed beds. Section X reviews and presents design concepts for fluid-bed reactors, a subject that strongly requires a revised outlook. While neither residence-time nor contact-time distributions lead to straightforward algorithmic design methods, derived lessons prove useful in the design of fluid-bed catalytic reactors. In Section X, the concept of contact-time distribution is shown to suffer from problems similar to residence-time distributions and surrounding misconceptions. Section XI uses these results to discuss the design of circulating fluid-bed and riser reactors. Ren...

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Tracer experiments and RTD's in heterogeneous reactor analysis and design

Cited by 17 publications

References 12 publications

A new technique for the determination of contact time distribution (CTD) from tracers experiments in heterogeneous systems

A new technique for the determination of contact time distribution (CTD) from tracers experiments in heterogeneous systems

Spiral Wound Reverse Osmosis Modules Decomposition into Elementary Units by Analyzing Stimulus Response Experiments: Characterization of the Solute Transfer across the Membrane

Residence-Time Distributions and Tracer Experiments in Chemical Reactor Design: The Power and Usefulness of a "Wrong" Concept

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