Segregation continuous reactor

Friis and Hamielec (48) offered some comments on the continuous reactor design problem suggesting that the dispersed particles have the same residence time distribution as the dispersing fluid and the system can be modeled as a segregated CSTR reactor. 

The completely segregated, continuous-how stirred tank reactor... 

Simulation Tools and Examples of Chemical Engineering Processes Intensities of Segregation in a Semi-Continuous Reactor... 

A continuous bulk polymerization process with three reaction zones in series has been developed. The degree of polymerization increases from the first reactor to the third reactor. Examples of suitable reactors include continuous stirred tank reactors, stirred tower reactors, axially segregated horizontal reactors, and pipe reactors with static mixers. The continuous stirred tank reactor type is advantageous, because it allows for precise independent control of the residence time in a given reactor by adjusting the level in a given reactor. Thus, the residence time of the polymer mixtures can be independently adjusted and optimized in each of the reactors in series (8). 

The definitions of the degree of mixing presented above aim at a local characterization of the mixture homogeneity in the physical space. There also exist more indirect mixing indices. The segregation index J of Danckwerts (12) is one of the most famous ones. It applies to continuous reactors and relies upon the variance of age J = Var oip/Var a>where a is the age of a molecule,... 

For a continuous reactor with a nonideal flow pattern, characterized by the differential residence time distribution E t), the following expression holds for the conversion nonideai. which is attained in case complete segregation of all fluid elements passing through the reactor can be assumed ... 

SCSTR = segregated continuous stirred tank reactor. 

SCSTR Segregated continuous stirred tank reactors... 

From Gerrens [1976]. BR = batch reactor PER = plug flow reactor HCSTR = homogeneous continuous stirred tank reactor = perfectly mixed flow reactor of this chapter SCSTR = segregated continuous stirred tank reactor. 

Figure 7.3. The conversion of chemical reactions of various orders (0.5, 1 and 2) in continuous reactors with perfect macro-mixing perfectly micro-mixed (full lines) and completely segregated (dotted lines), as a function of the Damkbhler number see defenition next page. For order 1 both lines coincide.

Tosun, G. (1997). A study of diffusion and reaction in unpremixed step growth copolymerization in a micro-segregated continuous stirred reactor, Ind. Eng. Chem., 36, 4075-4086. 

In what follows, both macromixing and micromixing models will be introduced and a compartmental mixing model, the segregated feed model (SFM), will be discussed in detail. It will be used in Chapter 8 to model the influence of the hydrodynamics on a meso- and microscale on continuous and semibatch precipitation where using CFD, diffusive and convective mixing parameters in the reactor are determined. 

Segregation may also be important if the reactants are fed to a reactor in an unmixed condition. This could be the case in any continuously fed reactor, either tubular (Fig. 5.133) or tank (Fig. 5.134). 

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