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INGAS INtegrated GAS Powertrain
Politecnico di Milano
Dipartimento di Energia
Research activity from Nov 08 to May 09
at Laboratory of Catalyis and Catalytic Processes
Gianpiero Groppi
INGAS 6 month meeting, Prague, 25-26 May 2009
1
INGAS INtegrated GAS Powertrain
Outline
• Development of new catalysts formulations
– Pd only catalysts: effect of the support
– Pt-Pd catalysts: Effect of Pt/Pd ratio
• Ecocat reference catalyst
– Tests on washcoat powders
– Monolith sample
– S-poisoning
INGAS 6 month meeting, Prague, 25-26 May 2009
2
INGAS INtegrated GAS Powertrain
Outline
• Pd only catalysts: effect of the support
• Pt-Pd catalysts: Effect of Pt/Pd ratio
• Ecocat reference catalyst
– Tests on washcoat powders
– Monolith sample
– S-poisoning
INGAS 6 month meeting, Prague, 25-26 May 2009
3
INGAS INtegrated GAS Powertrain
Effect of the support: preparation and characterization
Al2O3 and ZrO2: Tc = 950°C for 10 h
Ce and La added as nitrate, then calcined (Tc = 950°C for 10 h)
dry impregnation with Pd(NO3)2 solution, Tc = 600°C for 10 h
Pd load
% (w/w)
2
2
H2 Chem.
Support
BET :
SSA
[m2/g]
Vp
[cm3/g]
XRD
Al2O3
SASOL PURALOX SBA 140
117
0.49
0.28
12.5% w/w CeO2 – Al2O3
70
D%
dp [nm]
θ
( γ traces)
21
6
θ
( γ traces)
CeO2
12
9
10
11
5
25
2
3% w/w La2O3 – Al2O3
100
0.49
θ
( γ traces)
2
ZrO2
MELCAT – Chemicals
F20 936/01
19
0.17
Monocline
INGAS 6 month meeting, Prague, 25-26 May 2009
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INGAS INtegrated GAS Powertrain
Test on powder catalysts: apparatus and procedures
Purge Reducing Purge
Reaction
Reaction
pulse
Microreactor
gas in
He
thermocouple
internal
O2
A. U.
2 min
30min
quartz
wool
30 min
Powder
catalyst
H2O
CH4 - Ar
0
Gas out
Time
LEAN COMBUSTION : CH4 0.5%; O2 4%; H2O 1%; He/Ar; 93.5%; (30 min).
REDUCING PULSE:
CH4 0.5%; H2O 1% ;He/Ar 97.5%; (120 s)
PURGE:
He 95%, 5%N2 ( 30s )
T: 350°C, GHSV = 150.000 Ncm3/gcat/h, P = 1 atm.
INGAS 6 month meeting, Prague, 25-26 May 2009
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INGAS INtegrated GAS Powertrain
Conditioning by redox cycles
2% Pd/Al2O3
100
100
90
CH4 conversion %
90
CH4 conversion %
2% Pd/CeO2 - Al2O3
80
70
60
50
40
30
20
80
70
60
50
40
30
20
10
10
0
0
0
300
600
900
1200
1500
1800
0
300
600
Time (s)
80
80
CH4 conversion %
CH4 conversion %
90
70
60
50
40
30
20
10
0
300
600
900
1500
1800
1200
1500
1500
1800
Time (s)
INGAS 6 month meeting, Prague, 25-26 May 2009
2% Pd/ZrO2
100
90
0
1200
Time (s)
2% Pd/La2O3 - Al2O3
100
900
1800
70
60
50
40
30
20
10
0
0
300
600
900
1200
Time (s)
6
INGAS INtegrated GAS Powertrain
Lean combustion behaviour after conditioning
2% Pd/Al2O3
90
90
80
80
CH4 Conversion (%)
CH4 Conversion (%)
100
70
60
50
40
30
20
10
70
60
50
40
30
20
10
0
0
0
1000
2%
100
2000
3000
4000
5000
0
6000
1000
90
90
80
80
60
50
40
30
20
10
3000
4000
5000
6000
2% Pd/ZrO2
100
70
2000
Time (s)
Time (s)
Pd/La2O3 - Al2O3
CH4 Conversion (%)
CH4 conversion (%)
2% Pd/CeO2 - Al2O3
100
70
60
50
40
30
20
10
0
0
0
1000
2000
3000
4000
5000
Time (s)
INGAS 6 month meeting, Prague, 25-26 May 2009
0
1000
2000
3000
4000
5000
6000
Time (s)
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INGAS INtegrated GAS Powertrain
TOF before and after conditioning
2% Pd/Al2O3
2% Pd/Al2O3-CeO2
2% Pd/Al2O3-La2O3
2% Pd/ZrO2
100
CH4 conversion %
90
80
70
60
50
40
30
20
10
0
0
1
2
3
4
5
6
7
8
9
10
Red-Ox cycle
Isothermal PFR
T = 350°C
Support
As prepared
Conditioned
TOF [s-1]
TOF [s-1]
KC/KAP
PCH4 = 0.5 kPa
Al2O3
0.07
0.38
5
PH2O = 1.1 kPa
ZrO2
0.36
0.8
2
CeO2 – Al2O3
0.09
0.52
5
La2O3 – Al2O3
0.07
0.45
6
r = k . PCH4 . PH2O-1
INGAS 6 month meeting, Prague, 25-26 May 2009
8
INGAS INtegrated GAS Powertrain
Outline
• Pd only catalysts: effect of the support
• Pt-Pd catalysts: Effect of Pt/Pd ratio
• Ecocat reference catalyst
– Tests on washcoat powders
– Monolith sample
– S-poisoning
INGAS 6 month meeting, Prague, 25-26 May 2009
9
INGAS INtegrated GAS Powertrain
Characterization of bimetallic Pt-Pd systems
Constant nominal Pd load: 2% w/w
nominal Pt/Pd
Atomic ratio
0
0.10
0.25
1
Actual Pd e Pt
Load (% w/w)
(AAS)
Pt: 0.00
Pd: 2.14
Pt: 0.56
Pd: 2.50
Pt: 1.50
Pd: 2.50
Pt: 4.36
Pd: 1.95
INGAS 6 month meeting, Prague, 25-26 May 2009
actual Pt/Pd
dp XRD
Atomic ratio
as prepared
(nm)
0
0.12
0.33
1.22
PdO: 5
Pt: n.d.
Pd dispersion
(H2 Chemisorption)
21%
PdO: 8
Pt: n.d.
13%
PdO: 7
Pt: n.d.
12%
PdO: 6
Pt: 19
15%
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INGAS INtegrated GAS Powertrain
Activity of fresh catalysts
100
Pt/Pd = 0
Pt/Pd = 0.10
Pt/Pd = 0.25
Pt/Pd = 1
CH4Conversion (%)
90
80
70
60
50
40
30
20
10
0
0
300
600
900
1200
1500
1800
Time (s)
INGAS 6 month meeting, Prague, 25-26 May 2009
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INGAS INtegrated GAS Powertrain
Conditioning by redox cycles
0
500
cycles 3-7
cycle 2
cycle 1
initial activity
1000
1500
2000
2500
100
90
80
70
60
50
40
30
20
10
0
Time (s)
cycles 7-18
cycle 5-6
cycles 2-4
cycle 1
1500
Time (s)
INGAS 6 month meeting, Prague, 25-26 May 2009
2000
2500
cycle 4-11
cycle 3
cycle 2
cycle 1
initial activity
0
500
100
90 Pt/Pd = 1
80
70
60
50
40
30
20
10
0
1000
1500
Time (s)
CH4 conversion(%)
CH4 Conversion (%)
100
90 Pt/Pd = 0,25
80
70
60
initial activity
50
40
30
20
10
0
0
500
1000
Pt/Pd = 0,10
CH4 conversion (%)
CH4 conversion(%)
100
90 Pt/Pd = 0
80
70
60
50
40
30
20
10
0
0
500
2000
2500
initial activity
cycles 1-6
1000
1500
2000
2500
Time (s)
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INGAS INtegrated GAS Powertrain
1,0
0,9 Pt/Pd-0
Pt/Pd-0,10
0,8
0,7
Pt/Pd-0,25
0,6
0,5
0,4
0,3
0,2
0,1
0,0
0 30 60 90 120 150 180 210 240 270 300
Time (s)
INGAS 6 month meeting, Prague, 25-26 May 2009
1,0
Pt/Pd = 0
0,9
Extent of Pd oxidation
CH4/CH4
max
(350°C)
Pt-Pd catalysts: Reactivation behaviour
0,8
Pt/Pd = 0,10
0,7
0,6
0,5
0,4
Pt/Pd = 0,25
0,3
0,2
0,1
0,0
0
50 100 150 200 250 300 900
1200
1500
1800
Time (s)
13
INGAS INtegrated GAS Powertrain
Pt-Pd catalysts: TPO measurements
Pd/Pt = 1
Pt/Pd= 0,25
O2 (a.u.)
Pt/Pd = 0,10
Pt/Pd = 0
100 200 300 400 500 600 700 800 900 1000
T (°C)
INGAS 6 month meeting, Prague, 25-26 May 2009
14
INGAS INtegrated GAS Powertrain
Outline
• Pd only catalysts: effect of the support
• Pt-Pd catalysts: Effect of Pt/Pd ratio
• Ecocat reference catalyst
– Tests on washcoat powders
– Monolith sample
– S-poisoning
INGAS 6 month meeting, Prague, 25-26 May 2009
15
INGAS INtegrated GAS Powertrain
Tests on washcoat powders
100
100
90
90
80
CH4 conversion %
CH4 conversion %
Ecocat
2% Pd/Al2O3
2% Pd/ZrO2
2% Pd/Al2O3-CeO2
2% Pd/Al2O3-La2O3
70
60
50
40
30
20
80
70
60
50
40
30
20
10
10
0
0
300
600
900
1200
Time (s)
1500
1800
0
0
2
4
6
8
10
Red-Ox cycle
Kccond/Kcas received =2
INGAS 6 month meeting, Prague, 25-26 May 2009
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INGAS INtegrated GAS Powertrain
Tests on washcoat powders: S poisoning
16
100
14
SO2 (ppm)
12
10
8
6
4
2
Outlet SO2
0,018
80
0,016
0,014
60
0,012
0,010
40
0,008
0,006
20
0,004
0,002
0
0
0
1
2
Sads (gS/gwash)
CH4 Conversion [%]
Inlet SO2
0,020
3
4
Time (h)
5
6
0,000
0
1
2
3
4
5
6
Time [h]
T=400°C; WHSV=1.8E+5 Ncm3/g/h
CH4=6000 ppm; SO2=15 ppm; O2=5.2%; H2O=3.5%; N2 to balance
INGAS 6 month meeting, Prague, 25-26 May 2009
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INGAS INtegrated GAS Powertrain
Test on monolith samples: Experimental apparatus
36 cm
1.63 cm
15.2 cm
15.2 cm
2.5 cm
INGAS 6 month meeting, Prague, 25-26 May 2009
6x6 channels
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INGAS INtegrated GAS Powertrain
Test on monolith samples: preliminary results
Conversion
700
Gas temperature [°C]
100
CH4 conversion [%]
Temperature profiles
80
60
40
Flow
650
600
550
500
450
400
350
300
250
20
-5
0
10
15
20
25
Monolith length [mm]
80
0
200 250 300 350 400 450 500 550 600 650 700
5
70
60
Temperature [°C]
Ncm3/min
Q = 1215
GHSV = 50000 h-1 (monolith volume)
Feed: 3% O2; 0.7% CH4; 0% H2O
N2 to balance
Tmax
50
40
30
20
10
cfr Tad=180°C
0
0
20
40
60
80
100
CH4conversion %
INGAS 6 month meeting, Prague, 25-26 May 2009
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INGAS INtegrated GAS Powertrain
Test on monolith samples: preliminary analysis
Conversion [%]
100
r
80
k1 PCH 4
1 kads, H 2O PH 2O
k1 @ 400C 5.85E 2 moles/atm/s
60
Eact 34 kJ
k ads, H 2O @ 400C 1.02 E 3 .atm-1
40
Monolith 0% H2O
Ground monolith 1% H2O
Powder 1% H2O
20
H ads, H 2O 42 kJ
0
200 250 300 350 400 450 500 550 600 650 700
Temperature [°C]
Powder 0.06 g WHSV=1.5E+5 Ncm3/g/h
Ground monolith 0.009 g* WHSW=1.0 E+6 Ncm3/g/h
Monolith 0.147 g* WHSW=5.0 E+5 Ncm3/g/h
*hp: 15% w/w washcoat
INGAS 6 month meeting, Prague, 25-26 May 2009
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INGAS INtegrated GAS Powertrain
Annular Reactor
INLET
TC
OUTLET
• Laminar flow
negligible pressure drops
• High GHSV
106 – 107 Nl/Kgcat/h
distance from thermodynamic constraints
• Catalyst layer thickness 10 – 20m
• Small annular gap 0.5 mm
• Regular structured geometry
• Efficient heat dissipation by radiation
• Thermal equilibrium across the section of the ceramic tube
INGAS 6 month meeting, Prague, 25-26 May 2009
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INGAS INtegrated GAS Powertrain
Conclusions - 1
•
Marked activation of Pd-only catalysts upon reduction/re-oxidation cycles
•
Limited effect of the support on the overall catalytic activity of Pd-only catalyst
– Control of Pd dispersion (Al2O3>ZrO2)
– Slight decrease of TOF on increasing dispersion
•
Addition of Pt is beneficial on the activity of the as prepared catalysts but
depresses reactivation upon reduction/re-oxidation cycles
•
On increasing Pt/Pd ratio oxidation of Pd is progressively inhibited (alloying or
decoration/passivation)
INGAS 6 month meeting, Prague, 25-26 May 2009
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INGAS INtegrated GAS Powertrain
Conclusions-2
•
On Ecocat reference sample redox cycles provides limited
enhancement of activity
•
Ecocat reference sample (washcoat powders) shows a similar activity
to Al2O3 supported Pd catalysts
– Higher Pd load, lower dispersion?
•
Treatment in SO2 containing, lean combustion atmosphere results in
marked catalyst deactivation (about 1/10 at 15 mgS/gwash)
•
Preliminary tests on monolith samples show comparable activity with
powder catalysts. Significant temperature gradients are observed
along the catalyst bed which might bias kinetic investigation.
INGAS 6 month meeting, Prague, 25-26 May 2009
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INGAS INtegrated GAS Powertrain
Future activities
• Kinetic studies on Ecocat reference catalyst (what reactor?)
• Testing of materials under project boundary conditions
• Studies on S-poisoning and regeneration treatments
• Studies on hydrothermal stability
• Further characterization studies, particularly of bimetallic system (to
be discussed with ICSC-PAS)
INGAS 6 month meeting, Prague, 25-26 May 2009
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