C V V Satyanarayana
National Chemical Laboratory, Pune
National Seminar on “Creating Infrastructure for Adoption of Fuel cell Technology”, NTPC, Noida

1. Introduction to CSIR Fuel Cell Programme
2. Introduction to Fuel Processor catalysts
3. Development of Steam Reforming Catalysts & some results on
(a) Ethanol and LPG Steam Reforming
(b) Steam Reforming of iso-octane and Methane
4. Development of PROX Catalysts and Results
5. Remarks and Conclusions.
6. Future plans at NCL
National Seminar on “Creating Infrastructure for Adoption of Fuel cell Technology”, NTPC, Noida 2

Objective of the CSIR Fuel Cell programme
Development of 5 and 25 kW PEMFC power packs for stationary applications
Funded by
New Millennium Indian Technology Leadership
Initiative (NMITLI) Scheme, CSIR, New Delhi
Project Partners
National Chemical Laboratory
Spic Science Foundation
Bharat Heavy Electricals Limited
Sud-Chemie India Limited
National Seminar on “Creating Infrastructure for Adoption of Fuel cell Technology”, NTPC, Noida 3

Fuel Cell Power Pack
Main Components
Fuel Input
FUEL
PROCESSOR
Oxygen AIR
Hydrogen
Rich Gas
FUEL
CELL
STACK
POWER
CONDITIONER
DC Power
Output
AC Power
Output
Fuel Processor : Fuel processor is an integrated unit used for the conversion of raw fuel to hydrogen rich gas suitable for the fuel cell (NCL, SCIL)
Fuel Processing
Preheating
HEAT
RECOVERY
Water
Fuel Cell Stack : The hydrogen rich gas and oxygen (air) are fed to fuel cell stack to generate DC power (SPIC)
Power Conditioner: The DC power output is converted into useful AC power (BHEL )
National Seminar on “Creating Infrastructure for Adoption of Fuel cell Technology”, NTPC, Noida 4

National Seminar on “Creating Infrastructure for Adoption of Fuel cell Technology”, NTPC, Noida 5

COMPONENTS OF A PEM FUEL PROCESSOR
Desulphurizer Reformer Reformate cleanup
Fuel
Raw fuel cleaning
Fuel conversion
Steam reformer
Partial Oxidation
Autothermal reformer
CO reduction
Water gas shift reactor
( HTS , LTS)
Pref.
Oxidation
(PROX)
National Seminar on “Creating Infrastructure for Adoption of Fuel cell Technology”, NTPC, Noida 6

DS
SR
HTS
LTS
Catalysts in a PEM Fuel Processor
Catalyst Temp o C
Ni-Mo-ZnO 350
Reactions
ZnO + H
2
S

ZnS + H
2
O
Ni-Ce-Zr 700 C n
H
2n+2
+nH
2
O
 nCO + (2n+1)H
2
Fe-Cr
Cu-Zn-Al
380
200
CO + H
2
O

CO
2
+H
2
CO + H
2
O

CO
2
+H
2
PROX Pt-Zeolite 140 CO + 1/2O
2

CO
2
All reactors are fixed bed type
National Seminar on “Creating Infrastructure for Adoption of Fuel cell Technology”, NTPC, Noida 7


CH
4
+ H
2
O

CO + 3 H
2
;

H = + 210 kJ/mol

H
2
O / C = 2.5-3.0 (mol); 800-1000ºC, ~30 BAR

GHSV = 10000 – 15000 h -1

Ni ON REFRACTORY SUPPORTS

SUPPORTS: CaAl
2
O
4
FOR CH
4
FEED;

MgAl
2
O
4
SPINEL, K
2
O- FOR C3+ REFORMING

ACTIVITY DEPENDS ON Ni AREA

EQUILIBRIUM CONVERSION AND
SELECTIVITY
For MeOH Conventional CuO-ZnO-Al
2
O sufficiently low temperatures
3 operate at
National Seminar on “Creating Infrastructure for Adoption of Fuel cell Technology”, NTPC, Noida 8

DRAWBACKS OF CONVENTIONAL Ni -
BASED S R CATALYSTS

HIGH TEMPERATURES (800-1000ºC)

SENSITIVE TO SULFUR (<0.05 PPM);

HDS OF HEAVIES IS DIFFICULT IN A
FUEL PROCESSOR

SUSPECT FOR DEACTIVATION IN THE
PRESENCE OF OLEFINS

NOT PROVEN FOR OTHER FUELS SUCH
AS EtOH
National Seminar on “Creating Infrastructure for Adoption of Fuel cell Technology”, NTPC, Noida 9


Highly active to convert 100% of the hydrocarbon to its equilibrium composition of CO, CO the reaction temperature.
2
, methane and H
2 at

Should work at lowest possible steam/carbon ratios without deactivation due to filamental carbon.

Capable of handling high space velocities to achieve small catalyst volumes. Durability under long steady state continuous operation (>5000 hrs)

Should have high crush/mechanical strength under steam.

Has to withstand frequent On/Off cycles.

Tolerance to sulphur and other poisons.
National Seminar on “Creating Infrastructure for Adoption of Fuel cell Technology”, NTPC, Noida 10

Role of a support in SR Catalysts

To Improve mechanical strength and thermo-resistance

To enhance and stabilise metal dispersion (eg: Ni,Pt, Rh)

To suppress coke formation
Features of current SR catalyst supports

Refractory basic oxides (MgAl
2
O
4
, CaAl
2
O
4
, Al
2
O
3

Coke reduction by oxides of K, Mg, Mo, W, Ce, Sn
Ceria-Zirconia supports

The Ce 3+

Ce 4+ couple is more reversible in CeO
2
-
ZrO
2 than CeO
2 indicating that Ce ions in CeO
2
-ZrO
2 are more accessible. This can arise from the smaller size of the CeO
2 crystallites in CeO
2
-ZrO
2
.
National Seminar on “Creating Infrastructure for Adoption of Fuel cell Technology”, NTPC, Noida 11


Naptha and natural gas are the preferred feeds for H
2 production in Industrial Steam Reforming.

Due to wide distribution network, gasoline, diesel, kerosine, CNG and LPG are preferred for PEMFC.

Renewable feeds such as agro-ethanol and bio-gas does not lead to net CO
2 emissions.

Ni, Pd, Pt, Rh based catalysts are most suited for SR.
Ni based catalysts are the best in terms of cost and good performance. Ni is known to catalyse the breaking of C-C bond.
National Seminar on “Creating Infrastructure for Adoption of Fuel cell Technology”, NTPC, Noida 12

» Aim is to develop catalysts that work for SR of multiple fuels, viz., LPG, agro-ethanol, natural gas, methanol and naphtha.
» Ni supported on oxides that have red-ox properties such as CeO
2
, TiO
2
, CeO
2
-ZrO
2
, CeO
2
-ZrO
2
-TiO
2 have been prepared and screened.
,
»
Unique co-precipitation methodologies developed to yield nano-NiO particles (3-6nm) on high surface area supports.
»
Preliminary characterization is carried out by powder
XRD and BET surface area measurements. NiO crystallite sizes are calculated using Scherrer equation. Temperature programmed reduction studies carried out to monitor reducibility of the NiO on these supports.
National Seminar on “Creating Infrastructure for Adoption of Fuel cell Technology”, NTPC, Noida 13

100
SR of EtOH On NiO-CeO
2
-ZrO
2
Catalyst
Catalyst 2.5cc, Temp. 650
0
C , Steam/carbon 2.5-4
34
H
2
O/C = 2.5
33
90
32
80
31
70 H
2
O/C = 3
30
60
29
50
28
40
27
30
20
Ethanol Wt% in the feed
H2 VOLUME
CONVERSION
26
25
H
2
O/C = 4
10 24
0
0 25 50 75 100 125 150 175 200 225 250 275 300 325 350 375 400
TOS in hours
23
National Seminar on Fuel cell-Materials, Systems & Accessories, NMRL, Ambernath 14

100
SR OF LPG ON SCALE-UP CATALYST FROM SCIL
Temp. 700-730
0
C,Steam /Carbon=4.0,GHSV=21750-87000 h
-1
20
CONV
90
80 H
2
15
70
60
MTS HTS
87,000 h
-1
65,250 h
-1
10
50
40
43,500 h
-1
GHSV
CO
30
21,750h
-1
CO
2
5
20
10
0 50 100 150
Time on Stream (Hrs)
200 250
0
National Seminar on “Creating Infrastructure for Adoption of Fuel cell Technology”, NTPC, Noida 15

80
60
40
100
BUTANE & iso-BUTYLENE STEAM REFORMING
CATALYST 1.5cc, TEMP. 700
0
C, GHSV 14500 h
-1
, Steam/Carbon=4
BUTANE REFORMING iso-BUTYLENE REFORMING
20
0
0
Conversion
H2 Volume
20 40 60 80 100 120 140 160 180
TOS in hours
National Seminar on “Creating Infrastructure for Adoption of Fuel cell Technology”, NTPC, Noida 16

Steam Reforming of Iso-octane on 40%Ni/CeO
2
-ZrO
2
Reaction Temp 725 o
C, Steam/Carbon=3.6/1
8
80
GHSV=31000
60
40 GHSV=15500
6
Conversion
H2
CO2
CO
4
2
20
0
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32
TIME ON STREAM (Hrs)
0
National Seminar on “Creating Infrastructure for Adoption of Fuel cell Technology”, NTPC, Noida 17

100
80
60
40
CH4conv
H2con
COconc
20
0
600 625 650 675 700 725
Temperature(degrees)
SR of Methane on NiO-CeO
2
-ZrO
2
catalyst at various temperatures
National Seminar on “Creating Infrastructure for Adoption of Fuel cell Technology”, NTPC, Noida 18

SALIENT FEATURES OF NCL REFORMING
CATLYSTS

Common catalyst for steam reforming of EtOH, LPG and
Natural gas.

LPG supplied by Indian refineries has high content of olefins in addition to C
3 and C
4
. Reforming of 100%
Isobutylene was a good example to show that NCL catalyst can handle high concentrations of olefins in the feed

Variations in LPG composition does not have any bearing on performance. Catalysts show stable activity at full conversion even for 100% n-Butane

The Steam reforming catalysts developed at NCL show sulfur tolerance to low levels of sulfur. Hence, during steam reforming of agro-ethanol, desulfurisation of feed is not a pre-requisite.
National Seminar on “Creating Infrastructure for Adoption of Fuel cell Technology”, NTPC, Noida 19


A PROX catalyst should be highly active (CO conv >99.8%) such that it can handle high space velocities .

It has to operate in the temperature zone of LTS outlet temperature (200 o C) and PEM fuel cell stack inlet temperature (80 o C)

It should have good CO oxidation selectivity in order not to consume valuable H
2
.

Should operate at lower O
2
/CO ratios, preferably O
2
/CO

1

No methanation of CO should occur at reaction temperatures.

Presence of water and CO
2 should not lead to any deterioration in the long term performance.
National Seminar on “Creating Infrastructure for Adoption of Fuel cell Technology”, NTPC, Noida 20


Using HTS and LTS catalysts in series, the level of CO is brought down to 0.3 – 1.0%. The gas stream after the Shift reaction is further reacted with a preferential oxidation catalyst prepared at NCL, to bring down the CO to <10 ppm .

Supported gold catalysts using reducible oxide supports of Fe,
Mn, Co, Cr and Co-Mn oxide catalysts were prepared and evaluated in PROX reactor either in series with the steam reforming reactor or separately using typical gas mixtures. Mn and Mn-CO supports gave excellent results while other supported catalysts deactivated. Successful catalysts were tested for more than 100 hrs with various CO concentrations.

Since Pt based catalysts have been reported to work at high
GHSV’s with better stability, we have developed Pt based catalysts that work in 130-160 o C range and a zeolite based Pt catalyst has been scaled up to use in our processor programme.
National Seminar on “Creating Infrastructure for Adoption of Fuel cell Technology”, NTPC, Noida 21

PROX CATALYST: Au/ metal oxide, GHSV : 5000 h
-1
TEMPERATURE: 80-90
0
C,
12
10
8
6
4
2
0
-2
-4
-6
-8
-10
24
22
20
18
16
14
0
FEED 5100 PPM CO
CO in PPM
FEED 9600 PPM CO
10 20 30 40 50 60
TOS in hours
70 80 90 100
National Seminar on “Creating Infrastructure for Adoption of Fuel cell Technology”, NTPC, Noida 22

5.0
OXIDATION OF CO ON Pt/Al
2
O
3
CATALYST
Temp-175
O
C, CO- 9500ppm , O
2
/CO = 1.25
22500
4.5
20000
4.0
3.5
3.0
CO
GHSV
17500
15000
2.5
2.0
12500
10000
1.5
1.0
7500
0.5
5000
0.0
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34
2500
TOS in hours
National Seminar on “Creating Infrastructure for Adoption of Fuel cell Technology”, NTPC, Noida 23

Preferential Oxidation of CO on Pt-Zeolite
100
Feed- H
2
74.17%, CO
2
23.26%, CO 4900 ppm CO/O
2
=1
20
18
80
60
40
20
0
0
GHSV
Temp
2 4
10,000 h
135
0
C
-1
6 8 10 12
Time on Stream
16
15,000 h
-1
14
20,000 h
-1
12
10
145
0
C
8
6
4
2
0
14 16 18
National Seminar on “Creating Infrastructure for Adoption of Fuel cell Technology”, NTPC, Noida 24

Conclusions and Remarks

Novel supports and co-precipitation techniques developed to yield good SR catalysts containing nano-particles of NiO.

Common catalyst for SR of EtOH, LPG, CH
4 and MeOH.
100% conversions are achieved at reasonable temperatures.
These catalysts have capability to handle high space velocities.

Presence of olefins do not affect the performance. Variations in LPG composition has no bearing on the performance.
 NCL’s SR catalysts show sulfur tolerance to some extent. As a result, desulfurisation of the feed is not a must during the steam reforming of agro-ethanol.
 NCL’s PROX catalyst works in the temperature window of
135-150 o C and at O
2
/CO = 1. These less severe conditions help in saving of valuable H
2
.

Scale up and evaluation of these catalysts at Kg level has been successfully completed. A Fuel processor using complete train of these catalysts is operational at NCL.
National Seminar on “Creating Infrastructure for Adoption of Fuel cell Technology”, NTPC, Noida 25


Development of honeycomb based monolith ATR catalysts that combine SR and oxidation.

Development of cheaper transition metal based PROX catalysts.

Development of non-pyrophoric precious metal based steam reforming catalysts that can withstand on-off cycles and also have high sulphur resistance.

Development of sulphur resistant precious and nonprecious metal catalysts that can handle higher space velocities (>10,000 h -1 ) compared to the present water gas shift catalysts .

To develop selective methanation catalysts that methanate
CO in the presence of excess CO
2
.
National Seminar on “Creating Infrastructure for Adoption of Fuel cell Technology”, NTPC, Noida