This document discusses multiphase reactors, which involve gas, liquid, and solid phases. It covers the construction, classification, examples, design considerations, kinetics, advantages, and applications of these reactors. Specifically, it examines slurry bubble column reactors and slurry stirred tank reactors. It provides examples of industrial processes using multiphase reactors like hydrogenation, polymerization, and Fischer-Tropsch synthesis. Rate equations are also presented to model reactions in these complex systems.

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SUBMITTED TO:
Dr. BRISHTI MITRA
HEAD OF THE DEPARTMENT
CHEMICAL ENGINEERING
U.I.E.T. , C.S.J.M.U. , KANPUR
SUBMITTED BY:
SUPRIYA GUPTA
CSJMA14001390226
B.TECH , FINAL YEAR
CHEMICAL ENGINEERING

2.  Introduction
 Construction
 Classification
 Examples
 Design
 Advantages
 Disadvantages
 Applications
 Conclusion
 References
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3.  Multiphase reactor system
 Gas – reactant, Liquid – reactant or inert, Solid - catalyst
 Contact is achieved by suspending solids in liquid in presence
of gas
 Catalyst particle size: ~ 100 microns
 Operated in batch, semi-batch or continuous mode
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4.  Reaction Tank
 Gas Distributer
 Cooling Coils
 Probes
 Stirrer ( in case of
stirred tank vessel)
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5.  Slurry Bubbling reactor  Slurry Stirred reactor
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3 Phase
reactions
Hydrogenation of
vegetable oils
Polymerization
of ethylene
Fischer-Tropsch
synthesis
HYDROGEN
OIL
NICKEL
ETHYLENE
CYCLOHEXANE
ZEIGLER-
NATTA
HYDROCARBON
OIL
H2 / CO
IRON

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KINETICS
FLOW
PATTERN
PERFORMANCE
EQUATION

8. Step 1: Mass transfer of gas through gas film
Step 2: Mass transfer of gas through liquid film
Step 3: Mixing and diffusion of gas in the bulk liquid
Step 4: Mass transfer to the surface of catalyst particle
Step 5: Reaction at the catalyst surface 8
A ( g l ) + B ( l ) products
on solid
catalyst
dissolve

9. Rate observed (r)ob = kg ag (Cg – Cgi)
= kl ag (Cli – Cl)
= kc ac (Cl – Cs)
= k ac Cs 9

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Global rate expression :
ac Cg
ac + ac H + H + H
ag kg ag kl kc k
ro =
ac = external surface area of catalyst particles per unit .
volume of bubble free liquid
ag = bubble – liquid interfacial area per unit volume of
. . bubble free liquid
kg = gas side mass transfer coefficient
kl = liquid side mass transfer coefficient (bubble – liquid)
kc = liquid side mass transfer coefficient ( liquid – particle)
k = reaction rate constant
H = henry’s law constant ( Cgi = H Cli )

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Mixed flow G / any flow L Plug flow G / any flow L
F AO X A = (- ro ) Vr F AO dXA = (- ro ) dVr

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Mixed flow G / Batch L Plug flow G / Batch L
FAO X A = (- ro ) Vr F AO dXA = (- ro ) dVr

13.  High reaction rate
 Negligible intraparticle diffusion resistance
 Online catalyst addition and removal
 Better temperature control for highly exothermic reactions
 Easy and simple construction
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14.  Product separation is
difficult
 Low rate of mass transfer
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15.  Hydrogenation
 Oxidation
 Polymerization
 Halogenation
 Fermentation
 Waste water treatment
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16.  Advanced reactor technology for G/L processes
 Complex bubble behavior
 Feasible liquid solid separation method – combination
method
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17.  O. Levenspiel, Chemical Reaction Engineering, John
Willey & Sons
 J.M. Smith, Chemical Engineering Kinetics, 3rd edition,
McGraw-Hill
 https://nptel.ac.in>module 2> lec 18
 T Wang, J Wang, Y Jin – Industrial & Engineering
Chemistry…,2007- ACS Publications
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