biogas reforming processes improvements through process

BIOGAS REFORMING PROCESSES IMPROVEMENTS THROUGH PROCESS INTENSIFICATION

U. Izquierdo*,1, V.L. Barrio1, N. Lago1, J. Requies1, J.F. Cambra1, M.B. Güemez1, P.L. Arias1, J.R. Arraibi2, A.M. Gutiérrez2

1Dept. of Chemical and Environmental Engineering, School of Engineering, Bilbao, Spain 2Naturgas Energía Grupo S.A., Bilbao, Spain

THE USE OF MICRO STRUCTURED REACTORS FOR SYNGAS AND HYDROGEN PRODUCTION

OVERVIEW

1. INTRODUCTION

2. OBJECTIVES 3. EXPERIMENTAL METHODOLOGY 4. RESULTS 5. MAIN CONCLUSIONS 6. FUTURE PROSPECTS

Biogas - Renewable source Most harmful greenhouse gases (GHG) - Free CO2 fuel - Composition: CH4: 55-70% CO2: 27-44% H2 <1% H2S <3% NH3 traces

Hydrogen - Clean energy vector - Clean fuel - Main uses: Fuel cells

Heavy oil upgrading Desulfurization and upgrading of conventional petroleum

Reforming reactions - Dry reforming (DR) CH4 + CO2 ↔ 2 CO + 2 H2 ΔH0 = +247 kJ/mol - Biogas Oxidative Reforming (BOR) CH4 + ½ O2 → CO + 2 H2 ΔH0 = - 36 kJ/mol - Biogas Steam Reforming (BSR) CH4 + H2O ↔ CO + 3 H2 ΔH0 = + 206 kJ/mol - Water gas-shift (WGS) CO + H2O ↔ CO2 + H2 ΔH0 = - 41 kJ/mol

1. INTRODUCTION

2. OBJECTIVES

HYDROGEN AND SYNGAS PRODUCTION FROM BIOGAS REFORMING PROCESSES

- Development of an active and selective new catalytic systems

Ni/MgO Ni/Ce-Al2O3 Ni/Zr-Al2O3 Ni/Ce-Zr-Al2O3 Rh-Ni/Ce-Al2O3 Commercial

- Comparison between fixed bed and microreactor reaction systems

- Decentralized hydrogen production through process intensification

3.1. Catalyst preparation Incipient wetness impregnation

3.2. Reactors preparation Fixed bed reactor Microreactor

- Internal diameter: 6.3 mm - Channel width of 500 μm - Length: 32cm - Channel depth of 250 μm - Stainless steel 316-L - Design focused on Internal and external mass-transfer resistances.

- Improvements - Highest surface area/volume relationship - Smaller and more compact systems - Heat transfer optimization - Excellent temperature control - Highest selectivity for the desired products - Cheaper than other equivalent alternatives

3. EXPERIMENTAL METHODOLOGY

3.3. Activity measurements

Bench-scale Microactivity plant (PID Eng&Tech) Operation conditions: T=1073K and P=1bar Model biogas composition: CH4:CO2 = 1.5:1.0 Biogas oxidative reforming (Biogas OR)

O2/CH4 = 0.125, 0.25 and 0.50 Biogas steam reforming (Biogas SR)

S/C=1.0, 2.0 and 3.0 Tri reforming (TR)

O2/CH4 = 0.25 and 0.50 S/C=1.0, 2.0 and 3.0

Measured parameters: Methane conversion: X CH4 (%) = (VCH4

in - VCH4out) / VCH4

in · 100 Carbon dioxide conversion: X CO2 (%) = (VCO2

in - VCO2out) / VCO2

in · 100 Hydrogen yield: H2 yield (%) = VH2

out / (2·VCH4in + VH2O

in) · 100 (H2/CO)out molar ratio: (H2/CO)out = (VH2 / VCO)out

Where: Viin : volumetric flow-rate of reactant i (NmL/min).

Viout : volumetric flow-rate of product i (NmL/min).



3.4. Catalyst characterization - Chemical composition of calcined catalysts. ICP-AES instrument.

- Textural properties of the calcined and degassed catalysts. N2 adsorption-desorption isotherms: BET surface area and pore volume and diameter.

- Nickel dispersion, metal surface area and Ni crystallite size. H2-pulse chemisorption.

- Temperature programmed reduction profiles, TPR, for fresh and reduced catalysts.

- SEM micrographs of fresh reduced catalysts and tested catalysts: Surface composition (EDX) and morphology (Secondary electron detectors).

- XRD patterns for particle crystallite size.

- XPS technique was used to evaluate the surface characteristics.

4.1. RESULTS: Fresh catalysts characterization

4.1.1. Fresh catalysts. Chemical composition (ICP) and textural properties Catalyst Elemental composition (wt%) Surface area Pore volume Pore size (m2/g) (cm3/g) (Å) Commercial 12.4 (Ni) 0.4 (Ca) 21.6 0.09 169.5 20Ni/MgO 17.2 (Ni) 25.6 0.13 200.0 13Ni/6Ce-Al2O3 10.8 (Ni) 3.3 (Ce) 163.3 0.59 143.7 13Ni/8Zr-Al2O3 11.4 (Ni) 5.5 (Zr) 166.6 0.62 146.3 13Ni/3Ce-4Zr-Al2O3 10.6 (Ni) 2.7 (Ce) 3.6 (Zr) 151.0 0.60 153.2 13Ni-1Rh/6Ce-Al2O3 10.0 (Ni) 3.6 (Ce) 0.9 (Rh) 156.8 0.60 150.1 Ce-Al2O3 Support 195.0 0.76 150.1 Zr-Al2O3 Support 180.3 0.67 143.9 Ce-Zr-Al2O3 Support 191.7 0.74 150.7

4.1.2. H2 chemisorption results for reduced catalysts

Catalyst Metal Surface Dispersion Ni Crystallite size Ni crystallite size area (m2/g) (%) (nm) (nm) (XRD) 13Ni/6Ce-Al2O3 5.57 6.43 15.74 8 13Ni/3Ce-4Zr-Al2O3 5.13 7.28 13.90 7 13Ni-1Rh/6Ce-Al2O3 7.99 11.59 - 5

4.1.3. Calcined catalyst SEM micrographs

Commercial Ni/MgO Ni/Ce-Al2O3 Ni/Zr-Al2O3 Ni/Ce-Zr-Al2O3 Rh-Ni/Ce-Al2O3


700 800 900 1000 1100 1200

H2 c

onsu

mpt

ion

(a.u

.)

1073K

Commercial

Ni/MgO

Ce supportZr supportCe-Zr support

Ni/Ce-Al2O3

Rh-Ni/Ce-Al2O3

Ni/Ce-Zr-Al2O3

Ni/Zr-Al2O3

T (K)


700 800 900 1000 1100 1200

H2 co

nsum

ptio

n (a

. u.)

T (K)

4.1.4. TPR profiles of fresh calcined catalysts and supports

-0.8

0.0

0.8

1.6

2.4

3.2

4.0

-20

0

20

40

60

80

100

XCH4 XCO2 H2 yield H2out/COout

Mol

ar r

atio

%

S/C=3.0

Katalco Ni/MgO Ni/Ce-Al2O3 Ni/Zr-Al2O3 Ni/Ce-Zr-Al2O3 Rh-Ni/Ce-Al2O3 Equilibrium



0.0

0.8

1.6

2.4

3.2

4.0

0

20

40

60

80

100


Mol

ar r

atio

%

S/C=2.0

0.0

0.8

1.6

2.4

3.2

4.0

0

20

40

60

80

100


Mol

ar r

atio

%

S/C=1.0

0,0

0,8

1,6

2,4

3,2

4,0

0

20

40

60

80

100


Mol

ar ra

tio

%

Biogas SR activity results at different S/C ratios for Ni/Ce-Zr-Al2O3 catalyst

S/C=1.0 S/C=2.0 S/C=3.0

4.2. ACTIVITY RESULTS: BSR process in a FBR


4.2. ACTIVITY RESULTS: BOR process in a FBR

0.0

0.8

1.6

2.4

3.2

4.0

0

20

40

60

80

100


Mol

ar ra

tio

%

O2/CH4=0.50

0.0

0.8

1.6

2.4

3.2

4.0

0

20

40

60

80

100


Mol

ar ra

tio

%

O2/CH4=0.125

Biogas OR at O2/CH4=0.25

0

20

40

60

80

100


%

0.0

0.8

1.6

2.4

3.2

4.0

Mol

ar r

atio



0,0

0,8

1,6

2,4

3,2

4,0

0

20

40

60

80

100


Mol

ar ra

tio

%

Biogas OR activity results at different O2/CH4 ratios for Rh-Ni/Ce-Al2O3 catalyst

O2/CH4=0.125 O2/CH4=0.25 O2/CH4=0.50

4.2. ACTIVITY RESULTS: TR process in a FBR


TR at O2/CH4=0.5 and S/C=1.0

-20

0

20

40

60

80

100


%

-0.8

0.0

0.8

1.6

2.4

3.2

4.0

Mol

ar ra

tio


-40

-20

0

20

40

60

80

100


%

-1.6

-0.8

0.0

0.8

1.6

2.4

3.2

4.0

Mol

ar ra

tio


-60-40-20

020406080

100


%

-2.4-1.6-0.80.00.81.62.43.24.0

Mol

ar ra

tio



-1,6

-0,8

0,0

0,8

1,6

2,4

3,2

4,0

-40

-20

0

20

40

60

80

100


mol

ar ra

tio

%

Biogas TR activity results at O2/CH4=0.50 and different S/C ratios for Rh-Ni/CeAl2O3 catalyst

S/C=1 S/C=2 S/C=3

4.2. ACTIVITY RESULTS: TR and DR processes


0

20

40

60

80

100


%

0.0

0.8

1.6

2.4

3.2

4.0

Mol

ar ra

tio


-20

0

20

40

60

80

100


%

-0.8

0.0

0.8

1.6

2.4

3.2

4.0

Mol

ar ra

tio


-40

-20

0

20

40

60

80

100


%

-1.6

-0.8

0.0

0.8

1.6

2.4

3.2

4.0

Mol

ar ra

tio




-0,8

0,0

0,8

1,6

2,4

3,2

4,0

-20

0

20

40

60

80

100


mol

ar ra

tio

%

Comparison between DR and TR at O2/CH4=0.25 processes for Rh-Ni/Ce-Al2O3 catalyst

DR S/C=1 S/C=2 S/C=3

99,2

5,8

66,8 1,9

-1,6

-0,8

0,0

0,8

1,6

2,4

3,2

4,0

-40

-20

0

20

40

60

80

100


Mol

ar ra

tio

%

Biogas TR activity results at O2/CH4=0.50 and different S/C ratios for Rh-Ni/Ce-Al2O3 catalyst

S/C=1 S/C=2 S/C=3

94,6

0

95,7 90,2

1,2

0,0

0,8

1,6

2,4

3,2

4,0

0

20

40

60

80

100


Mol

ar ra

tio

%

Biogas OR activity results at different O2/CH4 ratios for Rh-Ni/Ce-Al2O3 catalyst

O2/CH4=0.125 O2/CH4=0.25 O2/CH4=0.50

94,35 99,1

39,1

75,3

1,7

-0,8

0,0

0,8

1,6

2,4

3,2

4,0

-20

0

20

40

60

80

100


Mol

ar ra

tio

%

Comparison between DR and TR at O2/CH4=0.25 processes for Rh-Ni/Ce-Al2O3 catalyst

DR S/C=1 S/C=2 S/C=3

99,5

67,7 80,0

1,6

0,0

0,8

1,6

2,4

3,2

4,0

0

20

40

60

80

100


Mol

ar ra

tio

%

Biogas SR activity results at different S/C ratios for Ni/Ce-Zr-Al2O3 catalyst

S/C=1.0 S/C=2.0 S/C=3.0

4.2. ACTIVITY RESULTS: Summary for FBR

84 86 88 90 92

0.08

0.16

0.24

Rh-N

i/Ce-

Al2O

3

Ni/C

e-Al

2O3

Ni/Z

r-Al

2O3

Ni/C

e-Zr

-Al 2O

3

Com

mer

cial

Ni/M

gO

Ni/A

l or N

i/Mg

surf

ace a

tom

ic ra

tios

Biogas OR hydrogen yield results (%) for catalysts tested in the FBR

Fresh catalyst Tested catalyst Metal dispersion ·102

Measured by ICP-AES

0.08

0.16

0.24

M

etal

disp

ersio

n de

gree

· 10

-2

66 68 70 72 74 76

0.08

0.16

0.24

0.08

0.16

0.24

Ni/M

gO

Com

mer

cial

Ni/Z

r-Al

2O3

Ni/C

e-Zr

-Al 2O

3

Ni/C

e-Al

2O3

Rh-N

i/Ce-

Al2O

3

Met

al d

isper

sion

degr

ee ·

10-2

Ni/A

l or N

i/Mg

surf

ace a

tom

ic ra

tios

Biogas TR hydrogen yield results (%) for catalysts tested in the FBR

Fresh catalyst Tested catalyst Metal disperson ·102

Measured by ICP-AES

4.3. RESULTS: Tested catalysts characterization

4.3.1. Relationship between XPS, ICP and H2 chemisorption

Ni/Ce-Al2O3

CH4 Turnover Frequency: TOF CH4 (s-1) XCH4 · NCH4

in / (wcat · wtMet · DMet / PmMet)

H2 Catalysts Productivity: PROD H2 (s-1)

NH2out / (wcat · wtMet · DMet / PmMet)

Where: Ni: molar flow of i (methane or hydrogen). wcat: catalyst weight in each reactor system. wtMe: elemental weight given by ICP-AES. DMe: metal dispersion for the catalyst. PmMe: metal molecular weight.

Ni/Ce-Zr-Al2O3

Ni-Rh/Ce-Al2O3

0

20

40

60

80

100

120

CH4 TOF (s-1) H2 PROD (s-1)

TOF

& P

RO

D ·

10-2

(s-1

)


Ni/Ce-Al2O3 Micro Ni/Ce-Al2O3 FBR Ni/Ce-Zr-Al2O3 MicroNi/Ce-Zr-Al2O3 FBR Rh-Ni/Ce-Al2O3 Micro Rh-Ni/Ce-Al2O3 FBR

0,0

0,8

1,6

2,4

3,2

4,0

0

20

40

60

80

100

XCH4 (%) XCO2 (%) H2 yield (%) H2out/COout

Mol

ar ra

tio

%


Ni/Ce-Al2O3 Micro Ni/Ce-Al2O3 FBR Ni/Ce-Zr-Al2O3 MicroNi/Ce-Zr-Al2O3 FBR Rh-Ni/Ce-Al2O3 Micro Rh-Ni/Ce-Al2O3 FBR

4. RESULTS: Comparison FBR Vs MICRO

Ni/Ce-Al2O3 CH4 Turnover Frequency: TOF CH4 (s-1) XCH4 · NCH4

in / (wcat · wtMet · DMet / PmMet)

H2 Catalysts Productivity: PROD H2 (s-1)

NH2out / (wcat · wtMet · DMet / PmMet)

Where: Ni: molar flow of i (methane or hydrogen). wcat: catalyst weight in each reactor system. wtMe: elemental weight given by ICP-AES. DMe: metal dispersion for the catalyst. PmMe: metal molecular weight.

Ni/Ce-Zr-Al2O3

Ni-Rh/Ce-Al2O3

4. RESULTS: Comparison FBR Vs MICRO

0

20

40

60

80

100

120

TOF CH4 (mol/g·s) PROD H2 (mol/g·s)

(TO

F &

PR

OD

) · 1

0-2 (

s-1 )


Ni/Ce-Al2O3 Micro Ni/Ce-Al2O3 FBR Ni/Ce-Zr-Al2O3 MicroNi/Ce-Zr-Al2O3 FBR Rh-Ni/Ce-Al2O3 Micro Ni-Rh/Ce-Al2O3 FBR

0,0

0,6

1,2

1,8

2,4

3,0

0

20

40

60

80

100

XCH4 (%) XCO2 (%) H2 yield (%) H2out/COout

Mol

ar ra

tio

%


Ni/Ce-Al2O3 micro Ni/Ce-Al2O3 FBR Ni/Ce-Zr-Al2O3 microNi/Ce-Zr-Al2O3 FBR Ni-Rh/Ce-Al2O3 micro Ni-Rh/Ce-Al2O3 FBR

5. MAIN CONCLUSIONS

• For all tested catalysts and studied processes, high CH4 and CO2 conversions were reached in the fixed bed reactor, in which Ni/Ce-Zr-Al2O3 and Rh-Ni/Ce-Al2O3 catalysts reached the highest hydrogen production yield.

• Reforming processes: Biogas OR process: Highest CO2 conversions and H2 yield were reached at O2/CH4=0.25. No filamentous

carbon deposition was detected in the catalytic surfaces. TR process: The best results for this process were measured at O2/CH4=0.25 and S/C=1.0. However, negative

CO2 conversions were measured operating at O2/CH4=0.50.

• Catalysts: Ni/Ce-Al2O3: High CH4 and CO2 conversion values were reached in all tested processes. Ni/Ce-Zr-Al2O3: For this catalyst, the highest CO2 conversion values were measured. In addition, also high

methane conversions were reached. Comparing the processes, it was considered the best catalysts for biogas SR process.

Ni-Rh/Ce-Al2O3: Very high CH4 and CO2 conversion and the highest hydrogen yields values were reached by this catalyst. It was considered the best catalyst for DR, biogas OR and TR processes.

• Reaction systems: For microreactors:

Ni/Ce-Al2O3 catalysts reached the highest hydrogen yield for biogas OR process. Ni/Ce-Zr-Al2O3 catalyst reached the highest hydrogen yield for biogas TR process. The catalytic activity measured in microreactors (TOF and PROD) was one order of magnitude higher.

• THE MICROREACTOR SYSTEM IMPROVES THE STABILITY OF THE PROCESS AND INCREASES THE WHSV, WHICH ARE NECESSARY FOR PROCESS INTENSIFICATION

THANK YOU FOR YOUR ATTENTION - Durability tests

- Test a new catalytic systems: Zeolites

- Experiments with another renewable feeds: bioalcohols

[email protected]

6. FUTURE PROSPECTS

BIOGAS REFORMING PROCESSES IMPROVEMENTS THROUGH PROCESS INTENSIFICATION

U. Izquierdo*,1, V.L. Barrio1, N. Lago1, J. Requies1, J.F. Cambra1, M.B. Güemez1, P.L. Arias1, J.R. Arraibi2, A.M. Gutiérrez2

1Dept. of Chemical and Environmental Engineering, School of Engineering, Bilbao, Spain 2Naturgas Energía Grupo S.A., Bilbao, Spain

THE USE OF MICRO STRUCTURED REACTORS FOR SYNGAS AND HYDROGEN PRODUCTION

biogas reforming processes improvements through process

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