*A pipe or tubular reactor ([[laminar flow reactor]](LFR))
Both types can be used as continuous reactors or batch reactors, and either may accommodate one or more solids ([[reagent]]s, [[catalyst]], or inert materials), but the reagents and products are typically fluids. Most commonly, reactors are run at [[steady-state (chemical engineering)|steady-state]], but can also be operated in a [[Transient state (chemical engineering)|transient state]]. When a reactor is first brought into operation (after maintenance or inoperation) it would be considered to be in a transient state, where key process variables change with time.
Mica how far, how you dey?
There are three main basic models used to estimate the most important process variables of different chemical reactors: