catcat03 - good info on support production
TRANSCRIPT
![Page 1: catcat03 - good info on support production](https://reader031.vdocuments.mx/reader031/viewer/2022012922/5440a9f5b1af9f650b8b4762/html5/thumbnails/1.jpg)
Catalysis and Catalysts - Manufacture
Solid Catalysts by Reactor
Fixed-bed catalysts– relatively large particles (several mm)– mechanical strength important (fines formation)
Moving-bed catalysts– idem fixed-bed– spherical particles (to flow smoothly)
Slurry-reactor catalysts– powders (25 m)– attrition resistance important– usually high density important (for easy settling)
Fluidised-bed and entrained-flow reactor catalysts– powders (20 - 200 m); well-controlled size distribution– attrition residence important
Structured catalytic reactors, e.g. monoliths
![Page 2: catcat03 - good info on support production](https://reader031.vdocuments.mx/reader031/viewer/2022012922/5440a9f5b1af9f650b8b4762/html5/thumbnails/2.jpg)
Catalysis and Catalysts - Manufacture
Shapes of Industrial Catalysts
Surface-volume ratio a’Mechanical strengthPressure dropPore-diffusion resistanceManufacture methods; costs
Irregular granule Sphere Pellet Extrudedcylindrical
TrilobeRing Minilith Wagon wheel
Monolithceramic
Monolithmetallic
Foam
![Page 3: catcat03 - good info on support production](https://reader031.vdocuments.mx/reader031/viewer/2022012922/5440a9f5b1af9f650b8b4762/html5/thumbnails/3.jpg)
Catalysis and Catalysts - Manufacture
Comparison of Catalyst Shapes
HydrodesulphurisationMethanationImpregnated noble-metal
Ammonia synthesisSilver cat. For formaldehyde
Carbon monoxide shiftHydrogenation
Hydrodesulphurisation
Steam reformingEthylene oxide production
Exhaust gas cleaning
Ammonia oxidationOther high-T processes
Low manufacturing costsRelatively high pressure dropLarge diffusion length
Not commonLow-surface-area catalysts
Regular shape; Most commonGood mechanical strength
Low pressure drop; Poor strength
High strength; Low pressure dropSmall diffusion length
Low pressure drop; Insensitive to dust; Small diffusion length
Low-surface-area catalysts
Spheres
Granules
Pellets
Extrudates
Rings
Monoliths
Gauzes
![Page 4: catcat03 - good info on support production](https://reader031.vdocuments.mx/reader031/viewer/2022012922/5440a9f5b1af9f650b8b4762/html5/thumbnails/4.jpg)
Catalysis and Catalysts - Manufacture
Pt Gauze
Reactor with gauze SEM images
New
Used
![Page 5: catcat03 - good info on support production](https://reader031.vdocuments.mx/reader031/viewer/2022012922/5440a9f5b1af9f650b8b4762/html5/thumbnails/5.jpg)
Catalysis and Catalysts - Manufacture
Monoliths
![Page 6: catcat03 - good info on support production](https://reader031.vdocuments.mx/reader031/viewer/2022012922/5440a9f5b1af9f650b8b4762/html5/thumbnails/6.jpg)
Catalysis and Catalysts - Manufacture
Specific Surface Area for Ni
Crystalline Size, d (nm)
Spe
cific
Sur
face
Are
a, S
A (
m2/g
)
0
100
200
300
400
500
600
700
0 10 20 30 40 50
![Page 7: catcat03 - good info on support production](https://reader031.vdocuments.mx/reader031/viewer/2022012922/5440a9f5b1af9f650b8b4762/html5/thumbnails/7.jpg)
Catalysis and Catalysts - Manufacture
Examples of Catalyst Manufacture
Mo salt Fe salt
Precipitation gelling
Drying
Grinding
Hydrothermic treatment Ripening
Drying
Pelleting
Calcining
Fe-moylbdate
Silicate Acid
Formation clear sol
Gelling
Water wash
Drying
SiO2
Melting
Cooling
Crushing
Screening
Leaching (pH ~ 14)
Raney Nickel
Ni-Al alloy
![Page 8: catcat03 - good info on support production](https://reader031.vdocuments.mx/reader031/viewer/2022012922/5440a9f5b1af9f650b8b4762/html5/thumbnails/8.jpg)
Catalysis and Catalysts - Manufacture
Catalyst Preparation
Bulk catalysts Supported catalysts
– Supports• Silica• Alumina• Zeolites• Activated Carbon
– Attachment of active phase• Co-precipitation• Impregnation• Deposition-precipitation• Chemical vapour deposition (CVD)• Sol-gel method
![Page 9: catcat03 - good info on support production](https://reader031.vdocuments.mx/reader031/viewer/2022012922/5440a9f5b1af9f650b8b4762/html5/thumbnails/9.jpg)
Catalysis and Catalysts - Manufacture
Raney Nickel
Mixing
Melting
Cooling
Crushing
Screening
Exposure to NaOH
solution (pH ca. 14
Porous Ni
High activity
High settling rate
Regeneration difficult
Unsatisfactory reproducibility
Pyrophoric
![Page 10: catcat03 - good info on support production](https://reader031.vdocuments.mx/reader031/viewer/2022012922/5440a9f5b1af9f650b8b4762/html5/thumbnails/10.jpg)
Catalysis and Catalysts - Manufacture
Ammonia Synthesis CatalystFusion Route
electric furnace
casting table
crushing
iron-oreH2, diluted O2
reductionpassivation
stabilized catalyst
undersized particles
screen
![Page 11: catcat03 - good info on support production](https://reader031.vdocuments.mx/reader031/viewer/2022012922/5440a9f5b1af9f650b8b4762/html5/thumbnails/11.jpg)
Catalysis and Catalysts - Manufacture
Catalyst Supports
Function– carrier active phase– stabilizes active phase– access to active sites
Important properties– stability at reaction conditions– stability at regeneration conditions– texture (surface area, pore structure)– active phase support interaction– inert/reactive– heat capacity– thermal conductivity– shape,size– mechanical strength– cost
![Page 12: catcat03 - good info on support production](https://reader031.vdocuments.mx/reader031/viewer/2022012922/5440a9f5b1af9f650b8b4762/html5/thumbnails/12.jpg)
Catalysis and Catalysts - Manufacture
Catalysts Supports and Applications
Alumina Hydrogenation, dehydrogenation, hydrotreating, hydrocracking,
FCC, reforming, isomerisation, car exhaust treatment,
methanol synthesis, low-temperature CO shift, steam reforming,
methanation, selective oxidation, alkene methathesis
Silica Polymerisation, hydrogenation, oxidation, hydrodemetallisation
Silica-alumina Ammoxidation, dehydrogenation
Zeolites FCC, hydrocracking, isomerisation, cyclisation, dewaxing,
methanol-to-gasoline process, light alkanes-to-aromatics,
organic synthesis
![Page 13: catcat03 - good info on support production](https://reader031.vdocuments.mx/reader031/viewer/2022012922/5440a9f5b1af9f650b8b4762/html5/thumbnails/13.jpg)
Catalysis and Catalysts - Manufacture
Catalysts Supports and Applications
Diatomceous earth SO2 oxidation, hydrogenation
Clays Hydrogenation, condensation
Cordierite monoliths Car exhaust, after-burning
Activated carbons Oxychlorination, hydrogenation (fine chemicals)
Titania Selective oxidation, SCR
Magnesium aluminate Steam reforming, methanation, methanol synthesis
![Page 14: catcat03 - good info on support production](https://reader031.vdocuments.mx/reader031/viewer/2022012922/5440a9f5b1af9f650b8b4762/html5/thumbnails/14.jpg)
Catalysis and Catalysts - Manufacture
Production of Silica (Porous SiO2)
Start from solution Na-silicate
Polymerisation
Gelation
Washing, Drying
H+
![Page 15: catcat03 - good info on support production](https://reader031.vdocuments.mx/reader031/viewer/2022012922/5440a9f5b1af9f650b8b4762/html5/thumbnails/15.jpg)
Catalysis and Catalysts - Manufacture
Production of Silica (Porous SiO2)
S i
O -
O -
O -
-O S i
O -
O -
-O O S i O S i
O -
O -
O -
O -
O - S i
O -
O -
-O O S i
O -
O -
O -
S iO 44 - S i3O 10
8 - S i2O 76 -
Silicate anions
Si
O-
-O OSi
O-
O-
O O
Si OSi O-
O-O-
-O
Si4O128-
Four-ring
Formation of silanol groups
-O-Si-O- + H+ -O-Si-OH
Generation of Si-O-Si bonds
-O-Si-OH + -O-Si-O- -O-Si-O-Si-O + OH-
Formation of ring structures
![Page 16: catcat03 - good info on support production](https://reader031.vdocuments.mx/reader031/viewer/2022012922/5440a9f5b1af9f650b8b4762/html5/thumbnails/16.jpg)
Catalysis and Catalysts - Manufacture
Formation of Silica Particle
Si
OH
OH
OHHO
Si
OH
OHHO
O
SiHO OH
OH
Si
O O
OHOH Si
O O
OH OHSi
O O
OH OHSi
O O
OHOH
OH
OO
Si
OH
+ H2O
1 2 followingpolymerization
monomer dimer particle of silica polycondensate
![Page 17: catcat03 - good info on support production](https://reader031.vdocuments.mx/reader031/viewer/2022012922/5440a9f5b1af9f650b8b4762/html5/thumbnails/17.jpg)
Catalysis and Catalysts - Manufacture
Formation of Gels: Sol-Gel Method
Solution of micelles (Hydro) gel
Colloidal solution Gel
pH ?? Surface charge depends on pH pH < 4 -Si-OH2+
pH > 9 -SiO -
Porous structures can be formed at pH 6 - 7
-Si-OH + -O-Si-OH -Si-O-Si- + OH-
![Page 18: catcat03 - good info on support production](https://reader031.vdocuments.mx/reader031/viewer/2022012922/5440a9f5b1af9f650b8b4762/html5/thumbnails/18.jpg)
Catalysis and Catalysts - Manufacture
Silica Production Process
Silicate Acid
Mixing
Drying
MillingClassification
Washing
Packaging
Mixing
Washing
Drying
Milling
Classifi-cation
Packaging
Silicate Acid
![Page 19: catcat03 - good info on support production](https://reader031.vdocuments.mx/reader031/viewer/2022012922/5440a9f5b1af9f650b8b4762/html5/thumbnails/19.jpg)
Catalysis and Catalysts - Manufacture
Drying
Critical step• capillary forces cause compression• pores collapse, porosity reduced
Can this be prevented?• exchange water for less polar fluid (e.g., alcohol)• dry under supercritical conditions
After drying • at low Temperature : hydrophilic• at high temperature: concentration of silanol groups low
hydrophobic
Si-O O Si O Si O Si O-
OH OH OH OH
OOOO
![Page 20: catcat03 - good info on support production](https://reader031.vdocuments.mx/reader031/viewer/2022012922/5440a9f5b1af9f650b8b4762/html5/thumbnails/20.jpg)
Catalysis and Catalysts - Manufacture
Fumed Silica’s
SiCl4 + 4 H2 + O2 SiO2 + 4 HCl
Pyrogenic silica
To HCl absorption
Cyclone
Deacidification
Burner
Cooler
Vaporiser
Mixer
Hydrogen
Oxygen (air)
Silicon tetrachloride
![Page 21: catcat03 - good info on support production](https://reader031.vdocuments.mx/reader031/viewer/2022012922/5440a9f5b1af9f650b8b4762/html5/thumbnails/21.jpg)
Catalysis and Catalysts - Manufacture
Production of Alumina (Porous Al2O3)
low pH, soluble
solution of Al2(SO4)3
base
precipitate
high pH, soluble
solution of Al(OH)3
acid
precipitate
Al is amphoteric
![Page 22: catcat03 - good info on support production](https://reader031.vdocuments.mx/reader031/viewer/2022012922/5440a9f5b1af9f650b8b4762/html5/thumbnails/22.jpg)
Catalysis and Catalysts - Manufacture
Precipitation Regions of Aluminium Compounds
pH
solubility
2 4 6 8 10 12
Region ofprecipitation
Al3+ AlO2-
14
Am
orp
ho
us
pre
cip
itate
Po
orly
cry
sta
llise
d
pse
ud
o b
oe
hm
ite
Cry
sta
llize
d b
aye
rite
p
lus
am
orp
ho
us
ma
teria
l
Cry
sta
llise
d
hyd
rarg
illite
Al-oxide amphoteric Soluble at low and high pH
Several precipitates,
dependent on conditions
![Page 23: catcat03 - good info on support production](https://reader031.vdocuments.mx/reader031/viewer/2022012922/5440a9f5b1af9f650b8b4762/html5/thumbnails/23.jpg)
Catalysis and Catalysts - Manufacture
Formation of Different AluminasAl-sulphate solution
Al2O3.3 SO3
pH < 2+
Base
at 3 < pH < 6precipitation of
microcrystalline boehmite gelAlO(OH)
Amorphous Al2O3
Na-aluminate solutionNa2O.Al2O3
pH > 12+
Acid
at 8 < pH < 11precipitation of
bayerite gelAl(OH)3
at 6 < pH < 8precipitation of
crystalline boehmite gelAlO(OH)
ageing at pH 8 and 353 K ageing at high pH
-Al2O3 -Al2O3
spinel structure: cubic close packing
Heating at about 1170 - 1270 K
-Al2O3 -Al2O3
-Al2O3
corund structure: hexagonal close packing
gibbsite gelAl(OH)3
-Al2O3
-Al2O3
Heating above 1370 K
Heating above 770 K
![Page 24: catcat03 - good info on support production](https://reader031.vdocuments.mx/reader031/viewer/2022012922/5440a9f5b1af9f650b8b4762/html5/thumbnails/24.jpg)
Catalysis and Catalysts - Manufacture
Dehydration of Alumina upon Heating
Al O Al O Al
O O O
O
O O O
O
H H
H
O
H H
H
O
H H
H
H H H
Al O Al O Al
O O O
O
O O O
Al O Al O Al
O O O
O
O-+ +
Chemically bonded H2O
![Page 25: catcat03 - good info on support production](https://reader031.vdocuments.mx/reader031/viewer/2022012922/5440a9f5b1af9f650b8b4762/html5/thumbnails/25.jpg)
Catalysis and Catalysts - Manufacture
Applications of Alumina
Alumina Application
-alumina hydrotreating
hydrocracking
methanation
reforming
hydrogenation
-alumina isomerisation
-alumina car exhaust
-alumina steam reforming
ethylene oxidation
![Page 26: catcat03 - good info on support production](https://reader031.vdocuments.mx/reader031/viewer/2022012922/5440a9f5b1af9f650b8b4762/html5/thumbnails/26.jpg)
Catalysis and Catalysts - Manufacture
Pore Volume Distributions
0.00
0.02
0.04
0.06
0.08
0.10
1 10 100 1000d pore (nm)
dV/dd
(m
l/g/
nm)
0.000
0.002
0.004
0.006
0.008
0.010
1 10 100 1000d pore (nm)
dV/dd
(m
l/g/
nm)
0.0
0.1
0.2
0.3
0.4
0.5
1 10 100 1000d pore (nm)
dV/dd
(m
l/g/
nm)
0
2
4
6
8
10
0.0 0.5 1.0 1.5 2.0d pore (nm)
dV/dd
(m
l/g/
nm)
Wide-pore Silia -Alumina
-Alumina ZSM-5
![Page 27: catcat03 - good info on support production](https://reader031.vdocuments.mx/reader031/viewer/2022012922/5440a9f5b1af9f650b8b4762/html5/thumbnails/27.jpg)
Catalysis and Catalysts - Manufacture
Early Zeolite Synthesis Method
Alumina Alkali Hydroxide Silica
Gel
Zeolite
373 K
![Page 28: catcat03 - good info on support production](https://reader031.vdocuments.mx/reader031/viewer/2022012922/5440a9f5b1af9f650b8b4762/html5/thumbnails/28.jpg)
Catalysis and Catalysts - Manufacture
Industrial Production of Na Aluminosilicate Zeolite
NaOH Al-source
vapour
H2O Si-source
slurry
Crystallisation
freshwater
Product todrying andcrushing
Belt conveyer
slurry
vapour
concentrated mother liquor
Mixing vessels
![Page 29: catcat03 - good info on support production](https://reader031.vdocuments.mx/reader031/viewer/2022012922/5440a9f5b1af9f650b8b4762/html5/thumbnails/29.jpg)
Catalysis and Catalysts - Manufacture
Zeolite Applications
Catalysts 14% AdsorbentsDesiccants
Natural 11%zeolites
Detergents 67%
8%
![Page 30: catcat03 - good info on support production](https://reader031.vdocuments.mx/reader031/viewer/2022012922/5440a9f5b1af9f650b8b4762/html5/thumbnails/30.jpg)
Catalysis and Catalysts - Manufacture
Kinetic Diameters of Molecules Compared with Zeolite Pore Size
0
0.2
0.4
0.6
0.8
1
Kin
eti
c d
iam
ete
r [n
m]
Zeolite-X, Y
ZSM-5
Zeolite-4A
Kin
etic
dia
met
er (
nm)
![Page 31: catcat03 - good info on support production](https://reader031.vdocuments.mx/reader031/viewer/2022012922/5440a9f5b1af9f650b8b4762/html5/thumbnails/31.jpg)
Catalysis and Catalysts - Manufacture
Preparation of H-Zeolite from Na-Zeolite
NH4+
- NH3> 570 K
![Page 32: catcat03 - good info on support production](https://reader031.vdocuments.mx/reader031/viewer/2022012922/5440a9f5b1af9f650b8b4762/html5/thumbnails/32.jpg)
Catalysis and Catalysts - Manufacture
Ion-Exchange of Zeolite Y for Na Removal
1st Exchange
Filtration & washing
Heating
2nd Exchange
Filtration & washing
Final drying
NaY sieve
NH4+ or
RE3+ solution
NH4+ or
RE3+ solution
Na+ solution
Na+ solution
![Page 33: catcat03 - good info on support production](https://reader031.vdocuments.mx/reader031/viewer/2022012922/5440a9f5b1af9f650b8b4762/html5/thumbnails/33.jpg)
Catalysis and Catalysts - Manufacture
Zeolites Classified by their Si/Al Ratio
Si/Al Ratio Zeolite Properties
Low (1-1.5) A, X Relatively low stability of frameworkLow stability in acidsHigh stability in basesHigh concentration of acid groupswith moderate acid strengthHydrophilic
Intermediate (2-5) ErioniteChabaziteClinoptiloliteMordeniteY
High (~10 to ) ZSM-5a Relatively high stability of frameworkErionitea High stability in acidsMordenitea Low stability in basesYa Low concentration of acid groups
with high acid strengthHydrophobic
a
By dealumination.
![Page 34: catcat03 - good info on support production](https://reader031.vdocuments.mx/reader031/viewer/2022012922/5440a9f5b1af9f650b8b4762/html5/thumbnails/34.jpg)
Catalysis and Catalysts - Manufacture
Solid-State Reactions in Y Zeolite During Steaming
Al
O
O
O
O
Si
Si
Si
Si Si OH
OH
Si
OH
Si
HO Si + Al(OH)3
Si OO SiSi
Si
O
Si
O
Non-framework species
Si(OH)4
H2O
H2O
From other parts of the lattice (creating meso-pores)
![Page 35: catcat03 - good info on support production](https://reader031.vdocuments.mx/reader031/viewer/2022012922/5440a9f5b1af9f650b8b4762/html5/thumbnails/35.jpg)
Catalysis and Catalysts - Manufacture
Trends in Catalytic Cracking Catalyst Performance
50 60 70 80
10
9
8
7
6
5
4
Conversion (vol%)
Cok
e yi
eld
(wt%
on
FF
)
Low a
lumina
am
orph
ous c
ats
High a
lumina
am
orph
ous c
ats
Zeolite ca
talysts
Zeolites +
riser c
racking
Coke selective zeolites (R
E-H-Y)
Highly coke selective cats (USY)
(1946)
(1955)(1964)
(1968-72)
(1980’s)
![Page 36: catcat03 - good info on support production](https://reader031.vdocuments.mx/reader031/viewer/2022012922/5440a9f5b1af9f650b8b4762/html5/thumbnails/36.jpg)
Catalysis and Catalysts - Manufacture
Activated Carbons
Positive– stable at all pH, T– high adsorption capacity– wide variety textural properties– "soft" ligand– not much erosion pumps, etc– inert
Negative– chemical reactivity (O2,.)
– mechanically weak– fines
![Page 37: catcat03 - good info on support production](https://reader031.vdocuments.mx/reader031/viewer/2022012922/5440a9f5b1af9f650b8b4762/html5/thumbnails/37.jpg)
Catalysis and Catalysts - Manufacture
Activated Carbon
Carbonaceous material peat, coal, biomass, sugar,polymers
High TPyrolysis
Porous material
H2OPartial gasification
Additional porosity Activated carbon
![Page 38: catcat03 - good info on support production](https://reader031.vdocuments.mx/reader031/viewer/2022012922/5440a9f5b1af9f650b8b4762/html5/thumbnails/38.jpg)
Catalysis and Catalysts - Manufacture
Structure of Activated Carbon from Wood
![Page 39: catcat03 - good info on support production](https://reader031.vdocuments.mx/reader031/viewer/2022012922/5440a9f5b1af9f650b8b4762/html5/thumbnails/39.jpg)
Catalysis and Catalysts - Manufacture
Functional Groups
O-
O
OO O O
O
O
O
OH
O
+ H2O, OH-
+ H2O, OH-
OOH
O
O
+ OH-
+ OH-
+ H-
+ H-
+ H- + H-+ H-
+ OH-, H-
![Page 40: catcat03 - good info on support production](https://reader031.vdocuments.mx/reader031/viewer/2022012922/5440a9f5b1af9f650b8b4762/html5/thumbnails/40.jpg)
Catalysis and Catalysts - Manufacture
Reactions with Carbon-supported Catalysts
Reaction Active Phase
Hydrogenations Pt, Pd, Ni
Acetylene + HCl to vinyl chloride HgCl2
Acetylene + HAc to vinyl acetate Zn(OCOCH3)2
![Page 41: catcat03 - good info on support production](https://reader031.vdocuments.mx/reader031/viewer/2022012922/5440a9f5b1af9f650b8b4762/html5/thumbnails/41.jpg)
Catalysis and Catalysts - Manufacture
Carbon-based Monolith Support
a. b.monolithicstructure
carbon
Carbon-coated monolith Integral-type carbon support
![Page 42: catcat03 - good info on support production](https://reader031.vdocuments.mx/reader031/viewer/2022012922/5440a9f5b1af9f650b8b4762/html5/thumbnails/42.jpg)
Catalysis and Catalysts - Manufacture
(Co)Precipitation
Solution solution
supersaturated solution
nucleation
growth
Coprecipitation mixed oxides
homogeneous orheterogeneous
Parameters – nature salts– cA,cB,...
– T , pH– ripening time– nucleation promotors– .......
![Page 43: catcat03 - good info on support production](https://reader031.vdocuments.mx/reader031/viewer/2022012922/5440a9f5b1af9f650b8b4762/html5/thumbnails/43.jpg)
Catalysis and Catalysts - Manufacture
Production of Catalysts by Precipitation
Precipitation and ageing
Mixed metal nitrates tank
Sodium carbonate tank
Mixed oxides and
carbonates
Filter
Drier and calciner
Mill
Weighing machines
Pelleting machine
Powder mixing bin
Catalyst pellets
![Page 44: catcat03 - good info on support production](https://reader031.vdocuments.mx/reader031/viewer/2022012922/5440a9f5b1af9f650b8b4762/html5/thumbnails/44.jpg)
Catalysis and Catalysts - Manufacture
Coprecipitation
Positive– components well
mixed on an atomic scale
– high loading possible– at high loadings
relatively high dispersion
– high thermostability
Negative– difficult scale-up– at low loadings
relatively low dispersion
![Page 45: catcat03 - good info on support production](https://reader031.vdocuments.mx/reader031/viewer/2022012922/5440a9f5b1af9f650b8b4762/html5/thumbnails/45.jpg)
Catalysis and Catalysts - Manufacture
Structure of Coprecipitate in Synthesis of Cu-Zn/Al2O3
brucitelayer
interlayer
brucitelayer
interlayer
brucitelayer
interlayer
brucitelayer
c0
= metal ions (Cu2+, Zn2+, Al3+)
= hydroxyl ions
= interlayer compounds (CO32-, H2O)
![Page 46: catcat03 - good info on support production](https://reader031.vdocuments.mx/reader031/viewer/2022012922/5440a9f5b1af9f650b8b4762/html5/thumbnails/46.jpg)
Catalysis and Catalysts - Manufacture
Catalysts Prepared by Coprecipitation
Reaction Catalytic elements
Catalysts
Hydrogenation Ni/Al
Steam reforming Ni/Al, Ni/Mg/Al
Methanol synthesis Cu/Zn/Al, Zn/Cr, Cu/Zn/Mg/Al
Higher Alcohol Synthesis Cu/Co/Zn/Al, Cu/Co/Zn/Cr
Fischer-Tropsch Co/Cr, Fe/Al
Supports for catalysts
Basic support Mg/Al
![Page 47: catcat03 - good info on support production](https://reader031.vdocuments.mx/reader031/viewer/2022012922/5440a9f5b1af9f650b8b4762/html5/thumbnails/47.jpg)
Catalysis and Catalysts - Manufacture
Impregnation
Wetting of support with solution precursor– "Wet" Excess solution– "Dry" Amount of solution=Pore Volume
Drying– Critical, tendency towards "egg-shell" catalyst
Calcination– Critical
• bursting support• interaction compounds• sintering
![Page 48: catcat03 - good info on support production](https://reader031.vdocuments.mx/reader031/viewer/2022012922/5440a9f5b1af9f650b8b4762/html5/thumbnails/48.jpg)
Catalysis and Catalysts - Manufacture
Catalyst Preparation by Impregnation
Wet impregnation
Dry impregnation
Bucket conveyor
Drip chute
Bucket
Drive wheel
Bucket filter
Tipper
To drying
Impregnating solution
Impregnating basin
Impregnating solution
Spray header
Support to be impregnated
Rotating drum
a.
b.
![Page 49: catcat03 - good info on support production](https://reader031.vdocuments.mx/reader031/viewer/2022012922/5440a9f5b1af9f650b8b4762/html5/thumbnails/49.jpg)
Catalysis and Catalysts - Manufacture
Relation between PZC and Surface Charge
H H+
Si O Si O Si
O- O- O-
Si O Si O Si
O O OH+ H HH+
Si O Si O Si
O O OH H H
Lower pH Higher pHpH = PZC
pH
Surface Charge
Species
Adsorption
pH increase
pH < PZC
positive
MOH2+
anions
pH = PZC
neutral
MOH
pH > PZC
negative
MO-
cations PZC
Alumina 8 - 9
Silica ~ 3
10% Alumina/Silica ~ 5
![Page 50: catcat03 - good info on support production](https://reader031.vdocuments.mx/reader031/viewer/2022012922/5440a9f5b1af9f650b8b4762/html5/thumbnails/50.jpg)
Catalysis and Catalysts - Manufacture
Adsorption from [Pt(NH3)4]2+ solution
Silica gel
-Alumina
0.3
0.2
0.1
06 7 8 9 10
pH
Adsorbed [Pt(NH3)4]2+ (mmol/g)
![Page 51: catcat03 - good info on support production](https://reader031.vdocuments.mx/reader031/viewer/2022012922/5440a9f5b1af9f650b8b4762/html5/thumbnails/51.jpg)
Catalysis and Catalysts - Manufacture
Active-Phase Distributions
Uniform Egg-shell Egg-white Egg-Yolk
a b c d
Active phase Support
![Page 52: catcat03 - good info on support production](https://reader031.vdocuments.mx/reader031/viewer/2022012922/5440a9f5b1af9f650b8b4762/html5/thumbnails/52.jpg)
Catalysis and Catalysts - Manufacture
Processes during Impregnation
Solution flow into pores
adsorption
adsorption
diffusion
evaporation
Adsorption/desorption + diffusion
Drying
![Page 53: catcat03 - good info on support production](https://reader031.vdocuments.mx/reader031/viewer/2022012922/5440a9f5b1af9f650b8b4762/html5/thumbnails/53.jpg)
Catalysis and Catalysts - Manufacture
Impregnation of -Alumina with Pt
4-
Al
OH+ PtCl62-2
Pt ClCl
Cl Cl
O O
Al Al
+ 2 HCl
Active phase Support
Impregnation time increases
![Page 54: catcat03 - good info on support production](https://reader031.vdocuments.mx/reader031/viewer/2022012922/5440a9f5b1af9f650b8b4762/html5/thumbnails/54.jpg)
Catalysis and Catalysts - Manufacture
Impregnation of -Alumina with PtInfluence of Coadsorbing Ions
a b c
Increasing citric acid concentration
Pt/Al2O3 Al2O3
![Page 55: catcat03 - good info on support production](https://reader031.vdocuments.mx/reader031/viewer/2022012922/5440a9f5b1af9f650b8b4762/html5/thumbnails/55.jpg)
Catalysis and Catalysts - Manufacture
Impregnation of Monoliths with NiInfluence of Drying Method
a. b. c. d. e.
Conventional drying
Forced-flow drying
Microwave drying
Freeze drying 1 h 24 h
![Page 56: catcat03 - good info on support production](https://reader031.vdocuments.mx/reader031/viewer/2022012922/5440a9f5b1af9f650b8b4762/html5/thumbnails/56.jpg)
Catalysis and Catalysts - Manufacture
Homogeneous Deposition Precipitation
Applicable in precipitation upon increasing pH– example: Ni2+ Ni(OH)2
Upon heating (370 K) urea in water decomposes slowly:
CO(NH2)2 + 3 H2O CO2 + 2 NH4+ + 2 OH-
pH increases slowly throughout particle– homogeneous loading
![Page 57: catcat03 - good info on support production](https://reader031.vdocuments.mx/reader031/viewer/2022012922/5440a9f5b1af9f650b8b4762/html5/thumbnails/57.jpg)
Catalysis and Catalysts - Manufacture
Homogeneous Deposition Precipitation
2 g/L NaOH
SiO2 2 g / 2 LNi(NO3)2.6H2O 0.5 g / 2 L
Peristaltic Pump (Gilson Minipuls)Injection Speed 50 mL/h pH Electrode
Time
pH
![Page 58: catcat03 - good info on support production](https://reader031.vdocuments.mx/reader031/viewer/2022012922/5440a9f5b1af9f650b8b4762/html5/thumbnails/58.jpg)
Catalysis and Catalysts - Manufacture
Chemical Vapour Deposition
![Page 59: catcat03 - good info on support production](https://reader031.vdocuments.mx/reader031/viewer/2022012922/5440a9f5b1af9f650b8b4762/html5/thumbnails/59.jpg)
Catalysis and Catalysts - Manufacture
Oil-Drop Coagulation
Organic phase
Aqueous phase
Oil overflow to recirculation
Oil
Water
Distributor coneSol
Product to ripening, washing, and drying