Ideal Continuous Stirred-Tank Reactor CSTR

1 Ideal Continuous Stirred Tank Reactor (CSTR) 

Ideal CSTR is a CSTR in which the mixing of fluid in the agitated vessel is assumed to be thorough or perfect. Perfect mixing is that which results in uniformity of solute concentration in the vessel volume. 

Assume that a reaction of the type A B is carried out in the reactor and the kinetic rate equation is 

Taking a steady-state balance of A around the reactor, we get 

The design of an ideal CSTR amounts to calculating the reactor volume V (using Equation 2.180) required to achieve a specified conversion x, of reactant A present in the feed stream at concentration Cao- 

Like the ideal batch reactor, the ideal CSTR is characterized by intense mixing. The temperature and the various concentrations are the same at every point in the reactor. The feed stream entering the reactor is mixed instantaneously into the contents of the reactor, inmiediately destroying the identity of the feed. Since the conqiosition and the temperature are the same everywhere in the CSTR, it follows that the effluent stream must have exactly the same composition and temperature as the contents of the reactor. 

The continuous stirred-tank reactor is also known as a continuous backmix, bachnaed, or mixed flow reactor. In addition to the catalytic reactors mentioned in the preceding paragraph, the reactors that are used for certain continuous polymerizations, e.g., the polymerization of styrene monomer to polystyrene, closely approximate CSTRs. 

Because of the intense mixing in a CSTR, temperature and concentration are the same at every point in the reactor. Therefore, as with the ideal batch reactor, r, does not depend on position. For a homogeneous reaction, Eqns. (3-1) and (3-3) simplify to 

Equation (3-15) describes the unsteady-state behavior of a CSTR. This is the equation that must he solved to explore strategies for starting up the reactor, or shutting it down, or switching from one set of operating conditions to another. 

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The length (height) and the diameter of tank reactor are close to each other or at least of the same order of magnitude. Tank reactors are usually equipped with a stirrer. In an ideal continuous stirred-tank reactor (CSTR), a feed stream is instantaneously mixed with the reaction mixture before molecules of the stream start to react. In reality, small reactors with vigorous stirring where relatively slow reactions occur behave as if they were ideal CSTRs. The... 

In an ideal continuous stirred tank reactor, CSTR, the composition and temperature are uniform throughout and the condition of the effluent is the same as that of the tank. When a battery of such vessels is employed in series, the concentration profile is step shaped if the abscissa is total residence time or the stage number. 

Ideal continuous stirred tank reactor (CSTR) behavior is approached when the mean residence time is 5-10 times the length needed to achieve homogeneity, which is accomplished with 500-2,000 revolutions of a properly designed stirrer. 

To complete the model of lime dissolution, a discretized particle size distribution is defined, with [x,] being the molar concentration of size fraction i with radius For an ideal continuous stirred tank reactor (CSTR) with residence time T the equation for updating the concentrations of the solid lime size fractions is... 

Ideal continuously stirred tank reactor (CSTR), including single and multiple stages... 

IDEAL CONTINUOUS STIRRED TANK REACTOR (CSTR)... 

Model 2 The Ideal Continuous Stirred Tank Reactor (CSTR) with V = Constant... 

Chin et al. (2007b) used pseudo-first order reaction kinetics combined with the ideal continuous stirred tank reactor (CSTR) model to evaluate the effect of initial concentration of pollutant on the performance of a submerged membrane photocatalytic reactor for the degradation of bisphenol A in water (Equation [21.2]) ... 

We consider the TAP reactor as a basic kinetic device for systematic studies of reaction-diffusion systems. In this chapter, we are going to (i) present and analyze models of different TAP configurations with a focus on their possibilities with respect to characterizing active materials and unraveling complex mechanisms, and (ii) demonstrate relationships between TAP models and other basic reactor models, that is, models for the ideal continuous stirred-tank reactor (CSTR), batch reactor (BR) and plug-flow reactor (PER). In some situations, the TZTR can be considered a simple building block for constracting the various models. 

The residence time distribution of a reactor is a function of the axial mixing within the reactor. The extreme cases are I) the ideal continuous stirred tank reactor (CSTR) with complete mixing and, 2) the ideal plug flow reactor (PFR) without any backmixing of the liquid during its flow through the reactor. The behavior of real reactors lies between these extremes. 

Problem 3-7 (Level 2) The homogeneous decomposition of the free-radical polymerization initiator dietiiyl peroxydicaibon-ate (DEPDC) has been studied in supercritical carbon dioxide using an ideal, continuous, stirred-tank reactor (CSTR). The concentration of DEPDC in tiie feed to tiie CSTR was... 

In Chapter 4, we defined the characteristics of two ideal continuous reactors, the ideal plug-flow reactor (PFR) and the ideal continuous stirred-tank reactor (CSTR). We use the term ideal to refer to these reactors because the conditions of mixing and fluid flow in them are defined very precisely. To recap... 

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