PLUG FLOW REACTOR (PFR)

PRESENTER?

FAKHRI

SYAFIQ

WAN

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

How PFR Operate?

MINI PFR

Factory scale PFR (Polyethylene reactor)

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.

Continuous Oscillatory Baffled Reactor

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

PFR APPLICATION

Wide variety of applications in either gas or liquid phase systems.

Common industrial uses :

a. Gasoline production.

b. Oil cracking.

c. Synthesis of ammonia from its elements.

d. Oxidation of sulfur dioxide to sulfur trioxide.