Analysis of plug flow reactors with variable mass density

AIChE Journal ◽  
2014 ◽  
Vol 60 (12) ◽  
pp. 4185-4189 ◽  
Author(s):  
James S. Vrentas ◽  
Christine M. Vrentas
Keyword(s):  
Mass Density ◽  
Variable Mass ◽  
Plug Flow ◽  
Flow Reactors

Mass Determination by Direct Measurement of Electron Scattering

1975 ◽  
Vol 33 ◽  
pp. 240-241
Author(s):  
M. K. Lamvik ◽  
A. V. Crewe
Keyword(s):  
Cross Section ◽  
Electron Scattering ◽  
Mass Density ◽  
Variable Mass ◽  
Scattering Cross Section ◽  
Mass Determination ◽  
Number Density ◽  
Cross Sectional ◽  
Thin Slice ◽  
Scattering Cross

If a molecule or atom of material has molecular weight A, the number density of such units is given by n=Nρ/A, where N is Avogadro's number and ρ is the mass density of the material. The amount of scattering from each unit can be written by assigning an imaginary cross-sectional area σ to each unit. If the current I0 is incident on a thin slice of material of thickness z and the current I remains unscattered, then the scattering cross-section σ is defined by I=IOnσz. For a specimen that is not thin, the definition must be applied to each imaginary thin slice and the result I/I0 =exp(-nσz) is obtained by integrating over the whole thickness. It is useful to separate the variable mass-thickness w=ρz from the other factors to yield I/I0 =exp(-sw), where s=Nσ/A is the scattering cross-section per unit mass.

Earthworms as plug flow reactors: a first-order kinetic study on the gut of the vermicomposting earthworm Eudrilus eugeniae

2018 ◽  
Vol 25 (31) ◽  
pp. 31062-31070 ◽  
Author(s):  
Katheem Kiyasudeen ◽  
Mahamad Hakimi Ibrahim ◽  
Syahidah Akmal Muhammad ◽  
Sultan Ahmed Ismail ◽  
Fadzil Noor Gonawan ◽  
...  
Keyword(s):  
Kinetic Study ◽  
Plug Flow ◽  
Order Kinetic ◽  
Eudrilus Eugeniae ◽  
Flow Reactors ◽  
First Order

Membrane-Assisted Reactor Engineering

2001 ◽  
Author(s):  
L. K. Doraiswamy
Keyword(s):  
Plug Flow ◽  
Operating Mode ◽  
Shape Selectivity ◽  
Membrane Reactors ◽  
Inorganic Membrane ◽  
Main Concern ◽  
Inorganic Membranes ◽  
Flow Reactors ◽  
Reactor Material ◽  
Membrane Tube

Like zeolites that combine shape selectivity with catalysis, membranes combine separation with catalysis to enhance reaction rates. The dual functionality of zeolites derives from the nature of the catalytic material, whereas that of membranes derives from the nature of the reactor material. The catalyst in the membrane reactor can be a part of the membrane itself or be external to it (i.e., placed inside the membrane tube). The chief property of a membrane is its ability for selective permeation or permselectivity with respect to certain compounds. Organic membrane reactions are best carried out in reactors made of inorganic membranes, such as from palladium, alumina, or ceramics. Good descriptions of these reactions and the membranes used are available in many reviews, for example, Gryaznov (1986, 1992), Stoukides (1988), Armor (1989), Govind and Ilias (1989), Bhave (1991), Zaspalis and Burggraaf (1991), Hsieh (1989, 1991), Shu et al. (1991), Shieh (1991), Gellings and Bouwmeister (1992), Tsotsis et al. (1993b), Harold et al. (1994), Saracco and Specchia (1994), Sanchez and Tsotsis (1996). A recent trend has been to develop polymeric-inorganic composite type membranes formed by the deposition of a thin dense polymeric film on an inorganic support (Kita et al., 1987; Rezac and Koros, 1994, 1995; Zhu et al., 1996). Another class of membranes under development for organic synthesis is the liquid membrane (Marr and Kopp, 1982; Eyal and Bressler, 1993). The permselective barrier in this type of membrane is a liquid phase, often containing a dissolved “carrier” or “transporter” that selectively reacts with a specific permeate to enhance its transport rate through the membrane. Our main concern in this chapter will be with inorganic membrane reactors. We commence our treatment with an introduction to the exploitable features of membrane reactors (with no attempt to describe membrane synthesis). Then we describe the main variations in design and operating mode of these reactors, develop performance equations for the more important designs, and compare the performances of some important designs with those of the traditional mixed- and plug-flow reactors. Finally, we present a summary of the applications of membrane reactors in enhancing the rates of organic reactions.

Reactor Design for Complex Reactions

2001 ◽  
Author(s):  
L. K. Doraiswamy
Keyword(s):  
Batch Reactor ◽  
Plug Flow ◽  
Reaction Network ◽  
Reactor Design ◽  
Batch Reactors ◽  
Complex Reaction ◽  
Mixed Flow ◽  
Flow Reactors ◽  
Design Procedures ◽  
Reactor Types

Procedures were formulated in Chapter 5 for treating complex reactions. We now turn to the design of reactors for such reactions. Continuing with the ethylation reaction, we consider the following reactor types for which design procedures were formulated earlier in Chapter 4 for simple reactions: batch reactors, continuous stirred reactors (or mixed-flow reactors), and plug-flow reactors. However, we use the following less formal nomenclature: A = aniline, B = ethanol, C = monoethyaniline, D = water, E = diethylaniline, F = diethyl ether, and G = ethylene. The four independent reactions then become Using this set of equations as the basis, we now formulate design equations for various reactor types. Detailed expositions of the theory are presented in a number of books, in particular Aris (1965, 1969) and Nauman (1987). Consider a reaction network consisting of N components and M reactions. A set of N ordinary differential equations, one for each component, would be necessary to mathematically describe this system. They may be concisely expressed in the form of Equation 5.5 (Chapter 5), or . . . d(cV)/dt = vrV (11.1) . . . The use of this equation in developing batch reactor equations for a typical complex reaction is illustrated in Example 11.1.

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