4 reactor design for multiple reactions

Chapter 4 REACTOR DESIGN FOR MULTIPLE REACTIONS... Complex reactions > Because parallel and series reactions are also require the BR and PFR < PFR BR Semi PFR CSTR CSTR PFR

Chapter 4 REACTOR DESIGN FOR MULTIPLE REACTIONS

Single reactions

+ + − =

Because of

• high and −

• small

PFR BR

Single reactions

Conversion

Multiple reactions

Selection Conversion

Parallel reactions

−

>

Because of

• high and

• small

• and are contravariant

<

Because of

• low

• high

• and are covariant

PFR

CSTR BR

Parallel reactions

+

+

−

>

>

Because of

• high , and

• small

>

<

Because of

• low

• high and

PFR BR

Semi BR

Semi PFR

Parallel reactions

+

+

−

<

<

Because of

• low ,

• high

<

>

Because of

• low

• high and

Semi BR

Semi PFR

CSTR

Series reactions

−− == = −− =

Because of

• high and

• high

• and are contravariant PFR

BR

Complex reactions

>

Because parallel and series reactions are also require the BR and PFR

<

PFR BR

Semi

PFR

CSTR CSTR PFR

Polymerization reactions

Polymer has a narrow distribution of molar

mass because of the same residence time

Polymer has a wide distribution of molar mass because the monomer and free radical concentrations decline

Polymer has a wide distribution of molar mass

because of different residence time

Polymer has a narrow distribution of molar mass because the monomer and free radical concentrations are maintained

PFR BR

CSTR

PFR BR

CSTR

Biochemical reactions

+

− =

+ The reaction rate is the same to the

autocatalytic reactions, reactor depends on

− =

+

Because of high , PFR

PFR CSTR

Conclusion of multiple reactions

Single reversible reactions

The effect of feed ratio on equilibrium conversion

Single reversible reactions

The effect of inert material on equilibrium conversion

Parallel reactions

+

+

Semi BR

Semi PFR

Semi BR Semi

PFR

Parallel reactions

+

+ ∆ <

− =

Concentrations of inert and are contravariant

+

− =

− = −

Concentrations of inert and are covariant

+

− =

Concentration of inert does not affect

Series reactions

−− == =

Because of

• low and high PFR

BR

+ −− == =

Excess because of

• low

• high and

Removal

• low

Semi BR Semi

PFR

Series reactions

− −= = − = −

Removal

• low

• shift equilibrium

Concentration of inert and are covariant ∆ <

Concentration of inert and are contravariant ∆ >

Recycling undesired

PFR CSTR

Use one reactant in excess for parallel

reactions Maximize =

− > − , use excess

− < − , use excess

Decrease concentration of inert

Reactor Separator Reactor Separator

Reactor Separator

Increase concentration of inert

Change

Mixing characteristics Temperature Pressure Catalyst

+

+

+

+

+

+