In this topic we have discussed working principle of a Batch Reactor. We've also discussed its kinetics like its Rate equation, Material and Energy balance. Its Design steps also have been discussed.
5. Reactor Design
Size of reactor
• Fix one of the 5
parameter
• Vf
• Ws
• S
• Vs
• Vr
• Shape
• Spherical
• cylindrical
• Dimensions
• Internals
• Inlets & outlets
Type of reactor
•BR
•CSTR
•PFR
•Fixed bed
reactor
•Fluidized bed
reactor
•Slurry reactor
Method of
operation
• Batch
• Continuous
• Semi-
Continuous
• Intermittent
6. Method of Operation
Thermodynamic
Basis
• Isothermal
• Adiabatic
• Constant
Volume
• Constant
Pressure
Flow Patern
• Counter
• Co Current
• Cross Current
Arrangment
• Series
• Parallel
• Recycle
• Or
Combination
Of Above
7. Introduction
• The reactants are
initially charged into
a container, are
well mixed, and are
left to react for a
certain period.
• The resultant
mixture is then
discharged.
8. Working Principle
• A batch reactor has neither inflow nor
outflow of reactants or products while
the reaction is being carried out
• This is an unsteady-state operation
where composition changes with time;
however, at any instant the
composition throughout the reactor is
uniform
9. Advantages
• They are preferred for establishing or
verifying kinetics because they are
o Simple in construction
o Require little or no auxiliary equipments
• Data can be collected easily if Isothermal
reactions are carried out under constant
volume condition
• High conversions
10. Disadvantages/limitations
• Intensity of process is localized and not the
global one
• Preferred for homogenous reactions only
• high labor costs per batch
• difficulty of large-scale production.
• Long idle time (Charging & Discharging
times) leads to periods of no production
• No instrumentation – Poor product quality
11. Application
• Typically for liquid phase reactions that
require long reaction times
• Used only when small amount of product is
required
• Favored when a process is in
developmental stage or to produce
expensive products
• Used to make a variety of products at
different times
12. Material Balance
• Also called mass balance.
• Is an application of law of
conservation of mass for the analysis
of physical systems.
• It states that:
• The mass that enters a system must, by
conservation of mass, either leave the
system or accumulate within the
system
13. Performance equation
(ṁA)in - (ṁA)out + (ṁA)gen - (ṁA)cons= (ṁA)acc/dep
since
(ṁA)cons - (ṁA)gen = (ṁA)net cons
In case of BR
(ṁA)in and (ṁA)out = 0
The above equation will become
-(ṁA)net cons = (ṁA)acc/dep
Dividing the above equation with molar mass
of component A
14. • -(ṄA)net cons = (ṄA)acc/dep
Since
After Substituting these values we will get
17. Energy Balance
• It is the application of law of conservation of energy
for the analysis of our physical system under
consideration
• The heat that enters a system must, by conservation of
heat/energy, either leave the system or accumulate within the
system
• Overall energy balance
• heat in – heat out + heat gen – heat cons = heat
acc/dep
18. Kinetics
Rate Law For Zero Order Reaction
• Assumptions:
o Isothermal
o constant volume
o irreversible reaction
Stoichiometry:
Assumed rate law:
24. Design Steps
FACTORS
• Type Of Reaction
• Scale Of Prodution
• Cost Of Equipment And Operations
• Safety
• Stability
• Life Expectency
• Ease Of Convertibility
25. Design steps
• There is no particular formula for selecting the
parameters of a reactor
•Experience
•knowledge of characteristics of reactors
•literature survey
Helps us in selection of parameters