Mesoporous Ni-CeO2-ZrO2-SiO2 composite catalyst for
steam reforming of n-butanol
Associate Professor, Department of Chemical Engineering, Indian Institute of Technology
Hyderabad, Kandi, Sangareddy-502285, Telangana, India.
Email: [email protected]
By
Dr. Sunil K. Maity
1
Background of the work Experimental
Results and discussion
Conclusions
Motivation and overview
Experimental set up, catalyst preparation & characterization, and definition of variables
Catalyst characterizationSteam reforming of n-butanol
Summary of the work
Outline
2
Global Energy Scenario
• 80% of energy comes from fossil
fuel
• 90% of organic chemicals are
derived from petroleum
Oil32.8%
Coal27.2%
Natuaral gas20.9%
Nuclear 5.8%
Hydro2.3%
Biofuels and waste10.2%
Others*0.8%
Renewable recourses
• Biomass
Background of the work
3
Key world energy statistics. International Energy Agency, 2011
Synthesis gas (CO+H2)
• Ammonia and fertilizers
• Fischer-Tropsch synthesis of methanol & dimethyl ether
• Fuel cell
• Source: Naphtha and natural gas
Bio-butanol
• Compatible with gasoline engines
Production of syngas from bio-butanol
Catalyst carrier: Ceria
• Oxygen storage/release property
• Low surface area
• Thermally unstable
• Prone to sintering at high temperature
Catalyst carrier: CeO2-ZrO2 mixed oxide
• Improved thermal stability
• Enhances oxygen storage capacity due to the formation of lattice defects
• Thermally unstable at high calcination temperature
• Low surface area
Background of the work
4
Steam reforming over Ni-CeO2-ZrO2-SiO2
composite catalyst
Catalyst carrier: Zirconia
• High hardness
• Good mechanical resistance
• High thermal stability
Catalyst carrier: CeO2-ZrO2-SiO2 mixed oxide
• High surface area
• Thermally stable Low surface area
Experimental Catalyst Preparation:
Evaporation-induced self-assembly method
• Silica was 70 wt%
• Abbreviation: xNiCaZbS where a and b are the mole ratio of CeO2
and ZrO2 and x represents wt% of nickel in the catalyst.
Catalyst characterization:
5
7
ExperimentalFixed-Bed Reactor Catalysis Science and Technology Lab.
Gas products
• H2, N2, CO, CO2, CH4
• CH4, ethane, ethylene, propane,
propylene, butanes, and butylenes
Liquid products
• Propanal, butanal
rateof moleof water fedS/C moleratio=
7 rateof moleof n-butanolfed
Steam reforming reaction
C4H10O +7H2O 4CO2 +12H2
2 4
Carbon conversion to synthesis gas (CCSG),%
rate of mole of CO+CO +CH formed100
rate of mole of carbon fed
Hydrogen yield, %
rate of mole of hydrogen formed100
12 (rate of mole of n-butanol fed) (fractional conversion of n-butanol)
Definition of variables
8
Catalysts SA PV dp20NiC0Z3S 263 0.21 3.2620NiC1Z2S 237 0.22 3.63
20NiC1.5Z1.5S 210 0.18 3.3920NiC2Z1S 192 0.18 3.60
SA = specific surface area, m2/g; PV = pore volume, cm3/g; dp =pore size, nm
Catalyst characterization
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
Qu
an
tity
ad
so
rbe
d (
cm
3/g
ST
P),
a.u
.
Relative pressure, P/Po
20NiC0Z
3S
20NiC1Z
2S
20NiC1.5
Z1.5
S
20NiC2Z
1S
2 3 4 5 6 7 8 9 10
dV
/dlo
g(D
) p
ore
vo
lum
e (
cm
3/g
A0),
a.u
.
Pore diameter, nm
B1
20NiC0Z
3S
20NiC1Z
2S
20NiC1.5
Z1.5
S
20NiC2Z
1S
Nitrogen adsorption-desorption
isotherm
Pore size distribution
BET surface area (Calcined catalyst)
TEM image
9
Catalyst characterization Powdered XRD pattern (Calcined catalyst)
Chemisorption and Ni crystallite size
and
Reduced catalyst
10 20 30 40 50 60 70 80
# ZrO2
###
#
CeZrO2
©
©©©
©
NiO€
€€€€€
2, deg
Inte
nsi
ty, a
.u.
20NiC2Z
1S
20NiC1.5
Z1.5
S
20NiC1Z
2S
20NiC0Z
3S
10 20 30 40 50 60 70 80
©©©
ZrO2
#
### #
CeZrO2
©
©
Ni*
***
Inte
nsi
ty, a
.u.
20NiC2Z
1S
20NiC1.5
Z1.5
S
20NiC1Z
2S
20NiC0Z
3S
2, deg
CATALYSTS MD SM dc, nm (Ni)20NiC0Z3S 0.09 0.62 33.120NiC1Z2S 0.88 5.86 21.6
20NiC1.5Z1.5S 0.72 4.82 23.120NiC2Z1S 0.74 4.91 23.7
10
Catalyst characterization Temperature programmed reduction
400 500 600 700 800 900 1000 1100
CeO2
ZrO2
Temperature, K
951K
20NiC2Z
1S
20NiC1.5
Z1.5
S
20NiC1Z
2S
20NiC0Z
3S
NiO
TC
D s
ign
al, a
.u.
815K860K597K
635K
705K
698K
686K
670K
773K
Bulk NiO
Surface ceria
Bulk ceria
Dispersed NiO
Dispersed NiO (inside mesopores)
Reduction of Ce4+ to Ce3+
NiO incorporated in the structure
11
Steam reforming of n-butanol Role of CeO2/ZrO2 mole ratio on the catalytic performance
0
20
40
60
80
100
Selectivity
to BUY, %
Conversion of n-butanol, %CCSG, %
Selectivity to CO2, %
Selectivity
to CH4, %
Selectivity
to CO, %
A 20NiC0Z
3S 20NiC
1Z
2S
20NiC1.5
Z1.5
S 20NiC2Z
1S
H2 yield, %
0.0
0.2
0.4
0.6
0.8
1.0
1.8
2.0
2.2
Ethane, % Propane, %
Propylene, %
Butanes, %
Propanal, %
Butanal, %
Sele
cti
vit
y t
o h
yd
rocarb
on
s, %
B 20NiC0Z
3S 20NiC
1Z
2S
20NiC1.5
Z1.5
S 20NiC2Z
1S
Reaction conditions: 873K, 8.79h-1 WHSV, and 2.5 S/C mole ratio.
CATALYSTS MD SM dc, nm (Ni)20NiC0Z3S 0.09 0.62 33.120NiC1Z2S 0.88 5.86 21.6
20NiC1.5Z1.5S 0.72 4.82 23.120NiC2Z1S 0.74 4.91 23.7
12
Steam reforming of n-butanol Effect of nickel loading on the catalytic performance
Reaction conditions: 873K, 8.79h-1 WHSV, and 2.5 S/C mole ratio.
0
5
10
15
20
60
80
100 25NiC
1Z
2S 30NiC
1Z
2S
Conversion of n-butanol, %CCSG, %
10NiC1Z
2S 15NiC
1Z
2S 20NiC
1Z
1S
Selectivity
to BUY, %
Selectivity
to CO2, %
Selectivity
to CH4, %
Selectivity
to CO, %
A
H2 yield, %
0.0
0.1
0.2
0.3
0.4
1
2
3
4
5
25NiC1Z
2S 30NiC
1Z
2S
10NiC1Z
2S 15NiC
1Z
2S 20NiC
1Z
2S
Sel
ecti
vit
y t
o h
yd
rocarb
on
s, %
Ethane, % Propane, % Propylene, % Butanes, %
B
CatalystsChemisorption
dc, nmRed
MD SM Ni10NiC1Z2S 0.95 6.34 17.315NiC1Z2S 0.85 5.70 18.520NiC1Z2S 0.88 5.86 21.625NiC1Z2S 0.23 1.56 41.430NiC1Z2S 0.21 1.42 44.3
13
Steam reforming of n-butanol Time-on-stream behavior of 20NiC1Z2S
Reaction conditions: 873K, 8.79h-1 WHSV, and 2.5 S/C mole ratio.
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30
0
5
10
15
20
25
70
80
90
100
Time-on-stream, h
Selectivity to CO, %
Selectivity to CH4, %
Hydrogen yield, %
Selectivity to CO2, %
CCSG, %
14
Conclusions
15
THANK YOU
