Type of Reactor |
Characteristics |
Continuously Stirred Tank Reactor (CSTR) |
Run at steady state with continuous flow of reactants and products; the feed assumes a uniform composition throughout the reactor, exit stream has the same composition as in the tank |
Kinds of Phases Present |
Usage |
Advantages |
Disadvantages |
1. Liquid phase 2. Gas-liquid rxns 3. Solid-liquid rxns |
1. When agitation is required 2. Series configurations for different concentration streams |
1. Continuous operation 2. Good temperature control 3. Easily adapts to two phase runs 4. Good control 5. Simplicity of construction 6 Low operating (labor) cost 7. Easy to clean |
1. Lowest conversion per unit volume 2. By-passing and channeling possible with poor agitation |
General Mole Balance Equation
Assumptions
1) Steady state therefore
2) Well mixed therefore r_{A} is the same throughout the reactor
Rearranging the generation
In terms of conversion
Reactor Sizing
Given –r_{A} as a function of conversion, –r_{A} = f(X), one can size any type of reactor. The volume of a CSTR can be represented as the shaded areas in the Levenspiel Plot shown below:
Reactors in Series
Given –r_{A} as a function of conversion, , –r_{A} = f(X), one can also design any sequence of reactors in series provided there are no side streams by defining the overall conversion at any point.
Mole Balance on Reactor 1
Mole Balance on Reactor 2
Given –r_{A} = f(X) the Levenspiel Plot can be used to find the reactor volume
For a PFR between two CSTRs