Catalysts generally react with one or more reactants to form an intermediate that subsequently give the final reaction product, in the process regenerating the catalyst. The following is a typical reaction scheme, where C represents the catalyst, A and B are reactants, and D is the product of the reaction of A and B:
M. Awais Yaqoob
(University of Engineering and Technology, Lahore)
• An industrial chemical reactor is
complex device in which heat transfer,
mass transfer, diffusion and friction may
occur along with chemical reaction with
provisions of safety and controls.
• Are vessels designed to contain
These are the two main basic
• All chemical processes are centered
in a chemical reactor. The design of a
chemical reactor Is the most
important factor in determining the
overall process economics.
At the start the design work , the following
information is presumably available:
. Reaction Type
. Need for catalyst
. Phases involve
. The mode of temperature and
pressure control, and
. Production capacity
• Direct Combination or Synthesis
A + B = AB
• Chemical Decomposition or
AB = A + B
• Single Displacement or
A + BC = AC + B
• Metathesis or Double
AB + CD = CB
In addition to the basic data, include:
• A heat and mass transfer characteristics
• Physical, chemical and thermodynamic
properties of components taking part in the
• CORROSION- erosion characteristics of any
potential hazard associated with reaction
• Reaction Rate
• “within- heating” describes
a process or reaction that
absorbs energy in the form
• Release energy in the form of
heat, light, or sound.
• ∆S > 0
• ∆H < 0
• Speed at which a chemical
reaction proceeds, in terms of
amount of product formed or
amount of reactant consumed
per unit time
• The nature of reaction
Basic Reactor Element
•Heat Transfer and
• Also called mass balance.
• Is an application of conservation of
mass to the analysis of physical
• The mass that enters a system must,
by conservation of mass, either leave
the system or accumulate within the
Mathematically the mass balance
for a system without a chemical
reaction is as follows:
•Input = Output +
Applications of Differential
• Ideal (stirred) Batch reactor
• Ideal tank reactor, also named
Continuous Stirred Tank Reactor
• Ideal Plug Flow Reactor(PFR)
• Is the phrase commonly used in
engineering for physical processes
that involve molecular and
convective transport of atoms and
molecules within physical system.
• Transfer of mass from high
concentration to low concentration.
• Is the transition of thermal energy
from a heated item to a cooler
• Transfer of Thermal Energy
Modes Of Heat Transfer
• internal coils,
• external heat exchanger,
• cooling by vapor phase
• fired heater.
Chemical Reactor can be
1. Batch Modes
2. Semi Continuous Modes
3. Continuous Modes
•One in which feed material
is treated as a whole for a
fixed period of time.
Types of Cooling
Single External Jacket
• Consists of an outer jacket which
surrounds the vessel.
• Heat transfer fluid flows around the jacket
and is injected at high velocity via nozzles.
• The temperature in the jacket is regulated
to control heating or cooling.
• The half coil jacket is made by welding a half
pipe around the outside of the vessel to create a
semi circular flow channel.
•A large reactor may use several coils to deliver
the heat transfer fluid.
Half Coil Jacket
Two Types of
• the catalyst in the
same phase as the
•Involves the use of a
catalyst in a different phase
from the reactants.
How the heterogeneous
•Is where something
sticks to a surface.
•Is a part of the surface
which is particularly good
at adsorbing things and
helping them to react.
• means that the
Kinds of Catalyst
• Strong Acids
• Base Catalysis
• Metal oxides, Sulfides, and Hydrides
• Metal and Alloys
• Transition-metal Organometallic
•Is an acid that ionizes
completely in an
• Is most commonly thought of as an
aqueous substance that can accept
• Base the chemical opposite of acids.
• Often referred to as an alkali if OH−
ions are involved.
•Form a transition between
acid/base and metal
Metal and Alloy
• Metal is a chemical elements whose
atoms readily lose electrons to form
positive ions (cations), and form metallic
bonds between other metal atoms and
ionic bonds between nonmetal atoms.
• The principal industrial metallic catalyst,
are found in periodic group VII
hydrogenation than are
metals such as platinum.
Fluid and Solid
• Multitubular reactors
• Fluidized beds
• Fixed Bed
• Spray Tower
• Two-Phase Flow
•These reactors are shell-
and-tube configuration and
have catalyst in the tubes.