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The continuous stirred-tank reactor (CSTR), also known as vat-or backmix reactor, mixed flow reactor (MFR), or a continuous-flow stirred-tank reactor (CFSTR), is a common model for a chemical reactor in chemical engineering and environmental engineering. A CSTR often refers to a model used to estimate the key unit operation variables when using ...
For a continuous stirred-tank reactor (CSTR), the following relationship applies: [1] [2] = where: is the reactor volume; is the molar flow rate per unit time of the entering reactant A
As can be seen, as the Damköhler number increases, the other term must decrease. The ensuing polynomial can be solved and the conversion for the rule of thumb Damköhler numbers found. Alternatively, one can graph the expressions and see where they intersect with the line given by the inverse Damköhler number to see the solution for conversion.
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.
Each plug of differential volume is considered as a separate entity, effectively an infinitesimally small continuous stirred tank reactor, limiting to zero volume. As it flows down the tubular PFR, the residence time ( τ {\displaystyle \tau } ) of the plug is a function of its position in the reactor.
The concept of residence time originated in models of chemical reactors. The first such model was an axial dispersion model by Irving Langmuir in 1908. This received little attention for 45 years; other models were developed such as the plug flow reactor model and the continuous stirred-tank reactor, and the concept of a washout function (representing the response to a sudden change in the ...
In a CSTR, one or more fluid reagents are introduced into a tank reactor which is typically stirred with an impeller to ensure proper mixing of the reagents while the reactor effluent is removed. Dividing the volume of the tank by the average volumetric flow rate through the tank gives the space time , or the time required to process one ...
General structure of a continuous stirred-tank type bioreactor. On the basis of mode of operation, a bioreactor may be classified as batch, fed batch or continuous (e.g. a continuous stirred-tank reactor model). An example of a continuous bioreactor is the chemostat. [citation needed]