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A CSTR often refers to a model used to estimate the key unit operation variables when using a continuous agitated-tank reactor to reach a specified output. The mathematical model works for all fluids: liquids, gases, and slurries. The behavior of a CSTR is often approximated or modeled by that of an ideal CSTR, which assumes perfect mixing. In ...
Real plug flow reactors with non-ideal behavior have also been modelled. [6] To predict the exact behavior of a vessel as a chemical reactor, RTD or stimulus response technique is used. The tracer technique, the most widely used method for the study of axial dispersion, is usually used in the form of: [7] Pulse input; Step input; Cyclic input ...
In this way, a higher efficiency may be obtained, or the size and cost of the PFR may be reduced. A PFR has a higher theoretical efficiency than a CSTR of the same volume. That is, given the same space-time (or residence time), a reaction will proceed to a higher percentage completion in a PFR than in a CSTR.
The residence time scale can take the form of a convection time scale, such as volumetric flow rate through the reactor for continuous (plug flow or stirred tank) or semibatch chemical processes: D a I = reaction rate convective mass transport rate {\displaystyle \mathrm {Da_{\mathrm {I} }} ={\frac {\text{reaction rate}}{\text{convective mass ...
The residence time of a fluid parcel is the total time that the parcel has spent inside a control volume (e.g.: a chemical reactor, a lake, a human body).The residence time of a set of parcels is quantified in terms of the frequency distribution of the residence time in the set, which is known as residence time distribution (RTD), or in terms of its average, known as mean residence time.
There are four main groups of chemical reactors - CSTR, PFR, semi-batch, and catalytic - with variations on each. Depending on the nature of the chemicals involved in the reaction, as well as the operating conditions (e.g. temperature and pressure), certain materials will perform better over others.
The volume of a CSTR necessary to achieve a certain conversion at a given flow rate is equal to the area of the rectangle with height equal to and width equal to . The volume of a PFR necessary to achieve a certain conversion at a given flow rate is equal to the area under the curve of F A o − r A {\displaystyle F_{Ao} \over -r_{A}} plotted ...
The most familiar form of continuous reactor of this type is the continuously stirred tank reactor (CSTR). This is essentially a batch reactor used in a continuous flow. The disadvantage with a single stage CSTR is that it can be relatively wasteful on product during start up and shutdown.