Steam Reforming of Ethane and Ethanol over Rh/Alumina:

a comparative study.Muhammad Bilal1, Claire Gillan1, Sam French2,

Martin Fowles2 and S David Jackson1

1Centre for Catalysis Research, WestCHEM, University of Glasgow, Glasgow G12 8QQ, Scotland, UK2Johnson Matthey plc, Belasis Ave, Billingham TS23 1LB UK

Hydrogen Hydrogen

AmmoniaAmmonia

NaphthaO2/N2

Steam Reforming

Steam Reforming

Hydrogen Hydrogen

AmmoniaAmmonia

NaphthaO2/N2

Steam Reforming

Steam Reforming

MethanolMethanol

Syngas Syngas

Hydrogen Hydrogen

AmmoniaAmmonia

O2/N2

Steam Reforming

Steam Reforming

MethanolMethanol

Syngas Syngas

Naturalgas

MethanolMethanol FischerFischerTropschTropsch

Syngas Syngas Hydrogen Hydrogen

AmmoniaAmmonia

NaturalgasO2/N2

Steam Reforming

Steam Reforming

MethanolMethanol FischerFischerTropschTropsch

Syngas Syngas

Biomass

Hydrogen Hydrogen

AmmoniaAmmonia

NaturalgasO2/N2

Steam Reforming

Steam Reforming

Ethane Steam Reforming

CnH2n+2 + nH2O nCO + (2n+1)H2

Steam Reforming

Water Gas Shift

Hydrogenolysis

CO + H2O CO2 + H2

C2H6 + H2 2CH4

Methanation

CO + 3H2 CH4 + H2O

Ethanol Steam Reforming

Ethanol decomposition

C2H5OH CO + CH4 + H2

C2H5OH + H2O 2CO + 4H2

Ethanol steam reforming

Ethanol dehydration

C2H5OH C2H4 + H2O

Ethanol dehydrogenation

C2H5OH CH3CHO + H2

Catalyst: 0.2 % Rh/Al2O3

Temp: 873 K

GHSV: 49,000

H2O:C2H6 /C2H5OH 5:1

Pressure: 20 barg

Experimental

2 7.5 27.5 31.5 55.5 74.5 79.5 100

Time on stream (h)

0

20

40

60

80

100

Con

vers

ion

(%)

Ethanol steamreforming over

alumina support

0

9

18

27

36

45

23.5 47.5 71.5 100

% Y

ield

Time on stream (hrs)

CH4 H2 CO2 CO C2H6 C2H4

Alumina selectivity

Ethanol Steam Reforming

Ethanol decomposition

C2H5OH CO + CH4 + H2

C2H5OH + H2O 2CO + 4H2

Ethanol steam reforming

Ethanol dehydration

C2H5OH C2H4 + H2O

Ethanol dehydrogenation

C2H5OH CH3CHO + H2

Ethanol Steam Reforming, alumina

Ethanol decomposition

C2H5OH CO + CH4 + H2

Water Gas ShiftCO + H2O CO2 + H2

0

9

18

27

36

45

23.5 47.5 71.5 100

% Y

ield

Time on stream (hrs)

CH4 H2 CO2 CO C2H6 C2H4

Alumina selectivity

-0.0055

-0.005

-0.0045

-0.004

-0.0035

-0.003

0

0.05

0.1

0.15

0.2

0.25

0 100 200 300 400 500 600 700 800 900 1000

Ion

curr

ent (

m/e

44)

Der

ivat

ive

wei

ght

Temperature (C)

Derivative weight 44

Alumina

0

20

40

60

80

100

0.0 5.0 10.0 15.0 20.0 25.0

Conversion

 (%)

Time on stream (h)

Ethane Ethanol

Rh/alumina, 873 K

Ethane, Rh/alumina

37.9%

14.9%14.5%

32.8%

H 2 C O C O 2 C H 4

Molar dry gas selectivity

Ethanol, Rh/alumina

Molar dry gas selectivity

51%

8%

15%

15%

7% 4%

H2 CO CH4 CO2 C2H4 C2H6

Ethanol, 873 K

24 48 72 100

Time on stream (h)

0

2

4

6

8

10

12

Yie

ld (%

)

Acetaldehyde DEE Acetone 1,1-DiethoxyE

2C2H5OH + H2O CH3COCH3 + CO2 + 4H2

2CH3CHO CH3CH(OH)CH2CHO

CH3CH(OH)CH2CHO + O(s) CH3CH(OH)CH2COO(s) + H(s)

CH3CH(OH)CH2COO(s) + H(s) CH3COCH3+ CO2 + H2

0

10

20

30

40

50

60

H2 CO CH4 CO2 C2H4 C2H6

Molar Selectivity (%)

Ethanol Ethane

C2H5OH

C2H4 + H2O

CO + CH4 + H2

C2H6

CO + H2

CO2 + H2

15

4

11

4

15 +H2O

+H2

+H2O

C2H6

CO + H2

CO2 + H2

CH4 + H2O

CH4

+2H2O+H2O

+2H2

+H216

15

141

‐5.50E‐03

‐5.00E‐03

‐4.50E‐03

‐4.00E‐03

‐3.50E‐03

‐3.00E‐03

‐0.0338

‐0.0336

‐0.0334

‐0.0332

‐0.033

‐0.0328

‐0.0326

‐0.0324

‐0.0322

‐0.032

‐0.0318

0 100 200 300 400 500 600 700 800 900 1000

ion curren

t, m/e  44

ion curren

t. m/e  44

Temperature (C)

Rh/alumina Alumina

1000

2400

3800

5200

6600

8000

100 600 1100 1600 2100 2600 3100 3600 4100

Inte

nsity

(a.u

.)

Raman shift (cm-1)

600C

1344

1594

CONCLUSIONS

Ethane: No significant catalyst deactivation at 873 K No evidence for filaments High methane selectivity O:C ratio in products, ~4:6

Ethanol: No significant deactivation at 873 K Filament formation High hydrogen selectivity O:C ratio in products, ~5:6

CONCLUSIONS

Ethane: Simpler reaction sequence No evidence for synthesis

Ethanol: Complex reaction sequence Synthesis as well as deconstruction

CONCLUSIONS

Ethane: primary reactions, steam reforming & hydrogenolysis secondary reactions, WGS & methanation

Ethanol: primary reactions, ethanol dehydration, ethanol decomposition, steam reforming, ethanol dehydrogenation, acid catalysis secondary reactions, WGS & ethene hydrogenation, synthesis reactions

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