For a plug flow reactor, the design equation is given as
However, when reaction is conducted at constant volume the design equation is identical to one for the batch reactor. If molar flow rate of component A is FAo and its concentration is CAo, then volumetric flow rate, υ, can be calculated as
And the reactor volume, V, is given as
Integrated solutions for a variety of reaction-types at constant pressures are provided below:
Plug Flow Reactor, Constant Pressure:
Zero order reaction: -rA = k
First order reaction: -rA = kCA
Second order reaction: -rA = kCA2
Third order reaction: -rA = kCA3
Second order reaction: -rA = kCACB
Third order reaction: -rA = kCA2CB
Third order reaction: -rA = kCACB2
Third order reaction: -rA = kCACBCC