A descriptive presentation on slurry reactors

1. Presented By:-
Nitin Kumar Singh
MT17CML009
VNIT, Nagpur

2. Contents
Introduction
Theory
1. Construction
2.Types of Slurry Reactors
Design Equation
Advantages and Disadvantages
Applications
References

3. Introduction
• A slurry is a thin sloppy mud or cement or, in extended use, any fluid
mixture of a pulverized solid with a liquid (usually water), often used
as a convenient way of handling solids in bulk.
• Slurries behave in some ways like thick fluids, flowing under gravity
but are also capable of being pumped if not too thick.

4. Theory
• A Slurry reactor is a multiphase reactor system in which all the three
phases i.e. Solids , Liquids and Gases can be reacted.
• In the Slurry Reactors the two-phase or the three-phase catalytic reactions
can be carried out.
• In three –phase reactor, gas and liquid reactants are brought into contact
with solid catalyst particles.
• In two–phase reactor, fluid phase is usually liquid reactant in contact with
the solid catalyst.
• The reaction of gaseous reactant with catalyst is usually carried out in fixed
bed reactor.
• In three –phase slurry reactor the gaseous reactant and solid catalysts are
dispersed in continuous liquid phase by mechanical agitation using stirrer.
The efficient stirring ensures nearly uniform composition throughout the
reactor

5. Reaction Steps in a Slurry Reactor :
1. Mass Transfer of Gas through Gas film.
2. Mass Transfer of Gas Through Liquid.
3. Dissolving bubble gas.
4. Mass transfer of dissolved gas through liquid film.
5. Reaction on the surface of the catalyst.

6. 1. Construction
 Reaction Tank
 Spargers
 Cooling Coils
 Probes
Stirrer

7. 2. Types of Slurry Reactors
• Bubble Column Reactor
• Fischer Tropsch Reactor
• Slurry Batch Reactor

8. Bubble Column Reactor

9. F-T Tubular Slurry Reactor

10. Slurry Batch Reactor for
Hydrogenation

11. Design Equation for a Slurry Reactor
 Rate can be expressed as:-
rab= kgag(Cg- Cgi)
= klag(Cli-Cl)
= kcac(Cl-Cs)
= ηkaccs
and we know, cgi= Hcli
𝑟 =
𝑎 𝑐 𝐶𝑔
𝑎 𝑐
𝑎 𝑔
∗
1
𝑘 𝑔
+
𝑎 𝑐
𝑎 𝑔
⋅
𝐻
𝑘 𝐿
+
𝐻
𝑘 𝑐 𝑎 𝑐
+
𝐻
𝜂𝑘𝑎 𝑐

12. Where,
rab = Rate of absorbtion
kg= Mass transfer coefficient of gas
kl= Mass transfer coefficient of liquid
k = Mass transfer coefficient of solid
ag= Bubble surface area
ac= Surface area of the catalyst(solid)
η= Effectiveness factor
H= Henry’s law constant
Cg= Concentration of the gas in bulk
Cgi= Concentration of the gas at the interface
Cl= Concentration of the liquid in bulk
Cli= Concentration of the liquid at the interface
Cs= Concentration of the solid catalyst

13. Advantages
• High heat capacity to provide good temperature
control.
• Potentially high reaction rate per unit volume of
reactor if the catalyst is highly active.
• Easy heat recovery.
• Adaptability to either batch or flow processing.
• The catalyst may readily be removed and replaced
if its working life is relatively short.
• Because of high intraparticle diffusion rate, small
particles can be used.

14. Disadvantages
• Generation of fine particles by abrasion of the catalyst.
• Catalyst removal by filtration may provoke problems with
possible plugging difficulties on filters, further time of
operation, and the costs of filtering systems may be a
substantial portion of the capital investment.
• Higher catalyst consumption than that of fixed - bed
reactors.
• Back mixed flow and the volume of the reactor are not
fully utilized.

15. Applications
• Hydrogenation of the Vegetable oil.
• Polymerization of ethylene.
• Waste water treatment.
• Oxidation of toluene to benzoic acid.
• Stack gas scrubbing with lime or magnesia.
• Olefin polymerization using catalyst suspension.

16. Reference
• Chaudhari, R. V., and P. A. Ramachandran. "Three phase slurry reactors." AIChE
Journal 26.2 (1980): 177-201.
• Buwa, Vivek V., Shantanu Roy, and Vivek V. Ranade. "Three‐phase slurry
reactors." Multiphase Catalytic Reactors: Theory, Design, Manufacturing, and
Applications (2016): 132-155.
• Zhang, Xinyu, and Goodarz Ahmadi. "Eulerian–Lagrangian simulations of liquid–gas–
solid flows in three-phase slurry reactors." Chemical Engineering Science 60.18
(2005): 5089-5104.
• Li, Hanning, and A. Prakash. "Heat transfer and hydrodynamics in a three-phase slurry
bubble column." Industrial & engineering chemistry research36.11 (1997): 4688-4694.
• Beenackers, A. A. C. M., and Willibrordus Petrus Maria Van Swaaij. "Mass transfer in
gas—liquid slurry reactors." Chemical Engineering Science 48.18 (1993): 3109-3139.

17. Thank You………………..!!!!!!!!!!!!!