Plug Flow Reactor: 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 F_Ao and its concentration is C_Ao, 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: -r_A = k

First order reaction: -r_A = kC_A

Second order reaction: -r_A = kC_A²

Third order reaction: -r_A = kC_A³

Second order reaction: -r_A = kC_AC_B

Third order reaction: -r_A = kC_A²C_B

Third order reaction: -r_A = kC_AC_B²

Third order reaction: -r_A = kC_AC_BC_C