What is the industrial application of PFR and CSTR?

The continuous-flow, well-stirred tank reactor or CSTR finds wide application in the chemical industry from pilot plant to full-scale production operation. The basic arrangement, sketched below, comprises a tank thermostated at some surrounding temperature Ta into which one or more reactant feed streams flow at some controlled rate. The contents react in the tank and are stirred either mechanically or as a consequence of the flow characteristics, and there is an outflow.

The various control parameters include:

· the inflow concentrations ci,0 of the different reactants;

· the total volumetric flow rate v through the reactor;

· the ambient temperature or the temperature of any cooling jacket Ta

· the inflow temperature T0 (which may be different from Ta)

whilst other features, such as reactor shape and size might be of interest at the design stage.

The response variables are the concentrations ci and the temperature T within the reactor.

The product/reactant mix flows out with concentrations ci and temperature T equal to the values in the reactor.

The continuous inflow of fresh reactants (and matching volumetric outflow of reactant and-product mixture) provides a thermodynamically open system, in which true steady state behaviour can be sustained 'indefinitely'.

by Baijnath