Enhanced Pd catalyst for abatement of methane emissions ... · PDF file• Methane...
1
Enhanced Pd catalyst for abatement of methane emissions from natural gas vehicles Introduction Catalyst Synthesis, Characterization and Testing Pd supported catalysts were synthesized by incipient wetness impregnation (IWI) on alumina supports: An aqueous solution of metal nitrates was prepared, then added to supports in the quantity required to fill the pore volume. Catalyst Characterization • Surface area: BET Micromeritics ASAP 2010 analyzer • Composition: SEM/EDX, Hitachi S3400N VP-SEM with an Oxford INCA EDX detector system operating at 20 kV and 80-90 mA • Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS) Pretreatment for 1hr @ 400°C with N 2 flow 50 mL/min and 30 min @ 350°C under a N 2 flow of 50 mL/min Flow of 50 mL/min of 1% CH 4 and 10% O 2 balance of He Catalyst Activity Temperature Programmed Oxidation (TPO) Micromeritics Autochem II 2920 with TCD Temperature ramp: 50-600°C at 10°C/min. Sample size: 50 mg Feed gas: 1% CH 4 , 10% O 2 , balance He. Flow: 50 mL/min Catalyst testing unit (CTU) (test with water) In house testing unit with FT-IR Detector Temperature ramp: 150-600°C at 3°C/min. Sample size: 500 mg Feed gas: 1% CH 4 , 10% O 2 , 6% CO 2 , 10% H 2 O, balance N 2 , Flow: 500 mL/min, ~55K (GHSV) Conclusions Results Name (composition) Active metal content Nominal/SEM EDX (wt%) Surface area (m 2 /g) T 50 1 (°C) Pd Zr Ti 0.5Pd/g-Al 2 O 3 2 0.50/0.52 - - 275 374 1Pd/g-Al 2 O 3 2 1.0/1.1 - - 240 354 0.5Pd/doped alumina 3 0.50/0.52 - - 149 357 0.5Pd/1Zr/doped alumina 3 0.50/0.47 1.0/1.0 - 145 348 0.5Pd/1Ti/doped alumina 3 0.50/0.57 - 1.0/0.67 146 375 0.5Pd/1Zr/g-Al 2 O 3 0.50/0.47 1.0/1.0 - 246 361 0.5Pd/1Ti/g-Al 2 O 3 0.50/0.58 - 1.0/0.73 230 407 0.5Pd/Silica 4 0.50/0.56 - - 199 376 0.5Pd/1Zr/Silica 4 0.50/0.53 1.0/0.52 - 194 371 0.5Pd/1Ti/Silica 4 0.50/0.59 - 1.0/0.64 204 370 Results (Cont.) • Surface area is not necessarily an indicator of catalytic performance • Composition has a greater effect on catalytic activity • Pd supported on commercial doped alumina exhibits highest activity Characterization and activity (by TPO) of Pd catalysts on various supports DRIFTS Analysis: comparison of 0.5Pd/g-Al 2 O 3 and 0.5Pd/doped alumina • Formate and bidentate carbonate peak area increased with time • Oxidation is more rapid on doped alumina than g-Al 2 O 3 • Dopant may cause structural defects which: • Supply a larger amount of lattice oxygen • Allow for a faster oxidation of surface species • Liberate active sites • Pd on commercially available doped alumina is the most active catalyst • DRIFTS identified differences in intermediate surface species emergence • Dopant in support may provide more lattice oxygen oxidizing surface species and liberating active sites Future Work • Aging studies in the presence of water to determine hydrothermal stability • Test catalyst in presence of sulphur to establish sulphur resistance 1400 1450 1500 1550 1600 1650 1700 Absorbance (a.u.) Wavelength (cm -1 ) DRIFTS spectra of 0.5%Pd/g-Al 2 O 3 @350°C 80 min 60 min 40 min 20 min 10 min 6 min 2 min Peak Area (a.u.) Bidentate Carbonate 0 20 40 60 80 100 Time (min) Formate Funding for this project was provided by the Government of Canada Program on Energy Research and Development (PERD), AFTER1 Project. Acknowledgements and References 1 Temperature at 50% methane conversion 2 gAl 2 O 3 prepared in –house 2 Commercial support 4 Commercial silica • Natural gas (NG) has received increased interest in the transportation sector as a low carbon fuel (abundant and inexpensive). • Lean burn natural gas engines are similar in performance to diesel engines. • Natural gas engines provide a cleaner option, with estimated 15-20% lower greenhouse gas (GHG) emissions [1], than gasoline and diesel engines but have methane (CH 4 ) slip emissions. • It is projected in the next 10 years CH 4 emissions will surpass those of CO 2 [2]. • CH 4 has a global warming potential 21 times greater than CO 2 . • Reduced CH 4 emissions can be achieved by using catalytic converters [3]. • The best known methane oxidation catalysts contain Pd which is highly active for the low temperature oxidation of methane but is a relatively expensive noble metal. • Objective: Develop a methane oxidation catalyst active in the range of NG lean burn engine exhaust temperature (300-480°C), with a reduced amount of noble metal. Methane oxidation activity evaluation in presence of water (CTU) • Water adversely affects methane oxidation activity • Methane oxidation activity of Pd/doped alumina catalyst has enhanced activity compared to Pd/g-Al 2 O 3 catalyst with half the amount of palladium Catalyst tes)ng unit (CTU) Gianni Caravaggio , Lioudmila Nossova, Raymond Burich and Nicola Maffei Natural Resources Canada, CanmetENERGY, Ottawa, ON, Canada © Her Majesty the Queen in Right of Canada, as represented by the Minister of Natural Resources, 2015. References: [1] “Study of Opportunities for Natural Gas in the Transportation Sector”; Marbek: Ottawa, ON, March 2010. [2] Johnson, J. Chemical & Engineering News, 92:27:10-15, 2014. [3] DOE Report, http://www.afdc.energy.gov/vehicles/natural_gas_emissions.html 0 10 20 30 40 50 60 70 80 90 100 110 0 100 200 300 400 500 600 Methane conversion [%] Temperature [°C] 1%Pd/galumina without water 0.5%Pd galumina + water 0.5%/doped alumina + water 1%Pd/galumina + water 0.5P%d/gAlumina 0.5%Pd/doped Alumina
Transcript of Enhanced Pd catalyst for abatement of methane emissions ... · PDF file• Methane...
Enhanced Pd catalyst for abatement of methane emissions from natural gas vehicles
Introduction
Catalyst Synthesis, Characterization and Testing Pd supported catalysts were synthesized by incipient wetness impregnation (IWI) on alumina supports: An aqueous solution of metal nitrates was prepared, then added to supports in the quantity required to fill the pore volume.
Catalyst Characterization • Surface area: BET Micromeritics ASAP 2010 analyzer • Composition: SEM/EDX, Hitachi S3400N VP-SEM with an Oxford INCA EDX detector system
operating at 20 kV and 80-90 mA • Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS)
Ø Pretreatment for 1hr @ 400°C with N2 flow 50 mL/min and 30 min @ 350°C under a N2 flow of 50 mL/min
Ø Flow of 50 mL/min of 1% CH4 and 10% O2 balance of He
Catalyst Activity Temperature Programmed Oxidation (TPO)
Ø Micromeritics Autochem II 2920 with TCD Ø Temperature ramp: 50-600°C at 10°C/min. Ø Sample size: 50 mg Ø Feed gas: 1% CH4, 10% O2, balance He. Ø Flow: 50 mL/min
Catalyst testing unit (CTU) (test with water) Ø In house testing unit with FT-IR Detector Ø Temperature ramp: 150-600°C at 3°C/min. Ø Sample size: 500 mg Ø Feed gas: 1% CH4, 10% O2, 6% CO2, 10% H2O,
balance N2, Flow: 500 mL/min, ~55K (GHSV)
Conclusions
Results
Name (composition) Active metal content
Nominal/SEM EDX (wt%) Surface area (m2/g) T50
1 (°C) Pd Zr Ti
0.5Pd/g-Al2O32
0.50/0.52 - - 275 374
1Pd/g-Al2O32 1.0/1.1 - - 240 354
0.5Pd/doped alumina3 0.50/0.52 - - 149 357
0.5Pd/1Zr/doped alumina3 0.50/0.47 1.0/1.0 - 145 348 0.5Pd/1Ti/doped alumina3 0.50/0.57 - 1.0/0.67 146 375 0.5Pd/1Zr/g-Al2O3
0.50/0.47 1.0/1.0 - 246 361 0.5Pd/1Ti/g-Al2O3 0.50/0.58 - 1.0/0.73 230 407 0.5Pd/Silica4 0.50/0.56 - - 199 376 0.5Pd/1Zr/Silica4 0.50/0.53 1.0/0.52 - 194 371 0.5Pd/1Ti/Silica4 0.50/0.59 - 1.0/0.64 204 370
Results (Cont.)
• Surface area is not necessarily an indicator of catalytic performance • Composition has a greater effect on catalytic activity • Pd supported on commercial doped alumina exhibits highest activity
Characterization and activity (by TPO) of Pd catalysts on various supports
DRIFTS Analysis: comparison of 0.5Pd/g-Al2O3 and 0.5Pd/doped alumina
• Formate and bidentate carbonate peak area increased with time
• Oxidation is more rapid on doped alumina than g-Al2O3 • Dopant may cause structural defects which:
• Supply a larger amount of lattice oxygen • Allow for a faster oxidation of surface species • Liberate active sites
• Pd on commercially available doped alumina is the most active catalyst • DRIFTS identified differences in intermediate surface species emergence • Dopant in support may provide more lattice oxygen oxidizing surface species and liberating active sites
Future Work • Aging studies in the presence of water to determine hydrothermal stability • Test catalyst in presence of sulphur to establish sulphur resistance
1400 1450 1500 1550 1600 1650 1700
Abs
orba
nce
(a.u
.)
Wavelength (cm-1)
DRIFTS spectra of 0.5%Pd/g-Al2O3 @350°C
80 min
60 min
40 min
20 min
10 min
6 min
2 min
Peak
Are
a (a
.u.)
Bidentate Carbonate
0 20 40 60 80 100
Time (min)
Formate
Funding for this project was provided by the Government of Canada Program on Energy Research and Development (PERD), AFTER1 Project.
Acknowledgements and References
1 Temperature at 50% methane conversion 2g-‐Al2O3 prepared in –house 2 Commercial support 4 Commercial silica
• Natural gas (NG) has received increased interest in the transportation sector as a low carbon fuel (abundant and inexpensive).
• Lean burn natural gas engines are similar in performance to diesel engines.
• Natural gas engines provide a cleaner option, with estimated 15-20% lower greenhouse gas (GHG) emissions [1], than gasoline and diesel engines but have methane (CH4) slip emissions.
• It is projected in the next 10 years CH4 emissions will surpass those of CO2 [2].
• CH4 has a global warming potential 21 times greater than CO2.
• Reduced CH4 emissions can be achieved by using catalytic converters [3].
• The best known methane oxidation catalysts contain Pd which is highly active for the low temperature oxidation of methane but is a relatively expensive noble metal.
• Objective: Develop a methane oxidation catalyst active in the range of NG lean burn engine exhaust temperature (300-480°C), with a reduced amount of noble metal.
Methane oxidation activity evaluation in presence of water (CTU)
• Water adversely affects methane oxidation activity
• Methane oxidation activity of Pd/doped alumina catalyst has enhanced activity compared to Pd/g-Al2O3 catalyst with half the amount of palladium
Catalyst tes)ng unit (CTU)
Gianni Caravaggio, Lioudmila Nossova, Raymond Burich and Nicola Maffei Natural Resources Canada, CanmetENERGY, Ottawa, ON, Canada
© Her Majesty the Queen in Right of Canada, as represented by the Minister of Natural Resources, 2015.
References: [1] “Study of Opportunities for Natural Gas in the Transportation Sector”; Marbek: Ottawa, ON, March 2010. [2] Johnson, J. Chemical & Engineering News, 92:27:10-15, 2014. [3] DOE Report, http://www.afdc.energy.gov/vehicles/natural_gas_emissions.html
0
10
20
30
40
50
60
70
80
90
100
110
0 100 200 300 400 500 600
Metha
ne con
version [%
]
Temperature [°C]
1%Pd/g-‐alumina without water
0.5%Pd g-‐alumina + water
0.5%/doped alumina + water
1%Pd/g-‐alumina + water
0.5P%d/g-‐Alumina 0.5%Pd/doped Alumina
![Pd Ru , electro-catalyst in direct alkaline ethanol fuel cells · Pd xRu 1-X, electro-catalyst in direct alkaline ethanol fuel cells Alixia Farrell; Evans Monyoncho[1]; Elena A. Baranova[1]](https://static.fdocuments.net/doc/165x107/5acf4e2e7f8b9a71028c8173/pd-ru-electro-catalyst-in-direct-alkaline-ethanol-fuel-xru-1-x-electro-catalyst.jpg)
