PFR V2
description
Transcript of PFR V2
CHARACTERISTIC Also known as tubular reactor. Consist of hollow pipe or tube through which reactants
flow. Operated at steady-state. Reactants are continually consumed as they flow down
the length of the reactor. For ideal PFR reactor, assume to be complete mixing
perpendicular to the direction of flow. There is ideally no back-mixing or diffusion in the reactor. No element of fluid overtaking or mixing of fluid in PFR. Phase involved primarily in gas phase.
PFR Used for?
Large-scale reactions
Fast reactions
Homogeneous or heterogeneous reactions
Continuous production
High-temperature reactions
PFR OPERATION
Reactants are continuously fed into the reactor. As plug flow down the reactor, the reaction will take
place. Result in an axial concentration gradient » change in
concentration over a distances from left to right but not radial direction.
Products and unreacted reactants flow out of the reactor continuously.
When isothermal operation is possible, temp will also vary with the axial direction.
Advantages
High Conversion per Unit Volume
Run for long periods of time without maintenance
Heat transfer rate can be optimized by using more, thinner tubes or fewer, thicker tubes in parallel
Low operating cost
Disadvantages
Undesired thermal gradient
Poor temperature control
Total shutdown when cleaning is expensive