Hydrogen can be produced from a variety of feed stocks. These include fossil resources, such as...

METHANOL AUTOTHERMAL REFORMING OVER Cu/ZnO/Al2O3 CATALYST FOR PURE HYDROGEN

PRODUCTION

Meriem Banou, Lemnouer Chibane and Brahim Djellouli

Faculty of Technology, University of Setif-1  Laboratory of Chemical Engineering Processes (LGPC), Department of

Chemical Process Engineering

Hydrogen can be produced from a variety of feed stocks. These include

fossil resources, such as natural gas and coal, as well as renewable resources, such

as biomass and water with input from renewable energy sources (e.g. sunlight,

wind, wave or hydro-power). A variety of process technologies can be used,

including chemical, biological, electrolytic, photolytic and thermo-chemical. Each

technology is in a different stage of development, and each offers unique

opportunities, benefits and challenges. Local availability of feedstock, the maturity

of the technology, market applications and demand, policy issues, and costs will all

influence the choice and timing of the various options for hydrogen production.

INTRODUCTION

Figure 1 : Some feedstock and process alternatives

KINETIC MODEL

(1)

(2)

(3)

(4)

The kinetic model established is based on Langmuir-Hinshelwood mechanism and the reaction rate of expressions are:

 Mathematical Modeli :{R, W, D}

j:{CH3OH, H2O, CO, CO2, H2,O2}

:

The model we have developed is based on the following simplifying assumptions: Plug flow in the bed, No radial profiles, The axial diffusion in the bed, the losses are negligible, The intra-particle diffusion is negligible, Steady state, Pseudo-homogeneous model, isothermal and isobaric The reactions on the surface of the membrane are ignored.

Initial Conditions

Table of Operating Conditions for simulationParametres Values

Temperature (°C) 200-300

Pressure in the reaction side (bar) 1-5

Pressure in the permeate side

(bar)

1

Reactor length (m) 30x10-2

Radius of the inner tube(m) 1.10x10-2

Membrane thikness (m) 50x10-6

Methanol molar flux (mol/s) 5.13x10-6

H2O/CH3OH 1.0-2.0

N2/ CH3OH 1-4

O2/ CH3OH 0.4-2.0

Catalyst Weight(g) 0.077x10-3

Results and discussion1/ Effet of molar ratio (O/C) and (S/C)

0,2 0,4 0,6 0,8 1,0 1,2 1,4 1,6 1,8 2,0 2,2

0,660

0,662

0,664

0,666

0,668

0,670

0,672

0,674

xCH3OH

YH2

1,60

1,65

1,70

1,75

Recovered H

ydrogenMet

han

ol C

onve

rsio

n

Molar ratio (O/C)

Figure 2: Effect of (O/C) on the performance of the reaction

Operating conditions: I = 3, S/C = 1.0, T =

260 ° C, 1 bar = Pp

0,2 0,4 0,6 0,8 1,0 1,2 1,4 1,6 1,8 2,0 2,2

0,710

0,712

0,714

0,716

0,718

0,720

xCH3OH

YH2

1,70

1,75

1,80

1,85

1,90

Recovered H

ydrogenMet

han

ol C

onve

rsio

n

Molar ratio (O/C)

Figure 3: Effect of (O/C) on the performance of the reaction

Operating conditions: I = 3, S/C = 1.0, T = 280 ° C, 1

bar = Pp

0,2 0,4 0,6 0,8 1,0 1,2 1,4 1,6 1,8 2,0 2,20,750

0,752

0,754

0,756

0,758

0,760

0,762

xCH3OH

YH2

1,80

1,85

1,90

1,95

Recovered H

ydrogenMet

han

ol C

onve

rsio

n

Molar ratio (O/C)

Figure 4: Effect of (O/C) on the performance of the reaction

Operating conditions: I = 3, S/C = 1.5, T = 260 °

C, 1 bar = Pp

0,2 0,4 0,6 0,8 1,0 1,2 1,4 1,6 1,8 2,0 2,20,800

0,805

0,810

0,815

0,820

0,825

0,830

0,835

0,840

2,00

2,05

2,10

2,15

xCH3OH

YH2

Recovered H

ydrogenMet

han

ol C

onve

rsio

n

Molar ratio (O/C)

Figure 5: Effect of (O/C) on the performance of the reaction

Operating conditions: I = 3, S/C = 1.5, T = 280 °

C, 1 bar = Pp

Recovered H

ydrogenMet

han

ol C

onve

rsio

n

Molar ratio (O/C)

Figure 6: Effect of (O/C) on the performance of the reaction

Operating conditions: I = 3, S/C = 2.0, T = 260 °

C, 1 bar = Pp

0,2 0,4 0,6 0,8 1,0 1,2 1,4 1,6 1,8 2,0 2,20,779

0,780

0,781

0,782

0,783

0,784

0,785

0,786

xCH3OH

YH2

1,8

1,9

2,0

2,1

2/Temperature effect

200 220 240 260 280 300

0,2

0,4

0,6

0,8

0,0

0,5

1,0

xCH3OH

YH2

Recovered H

ydrogenMet

han

ol C

onve

rsio

n

Temperature (°C)

Figure 7: Effect of the temperature on the performances of the reaction

Operating conditions: I=3, S/C=1.0, O/C=0.4,

P= 1 bar, Pp=1 bar

200 220 240 260 280 300

0,1

0,2

0,3

0,4

0,5

0,6

0,7

0,8

xCH3OH

YH2

0,0

0,5

1,0

1,5

2,0

Recovered H

ydrogenMet

han

ol C

onve

rsio

n

Temperature (°C)

Figure 8: Effect of the temperature on the performances of the reaction

Operating conditions: I=3, S/C=1.0, O/C=0.4,

P= 3 bar, Pp=1 bar

200 220 240 260 280 300

0,1

0,2

0,3

0,4

0,5

0,6

0,7

0,8

xCH3OH

YH2

0,0

0,5

1,0

1,5

2,0R

ecovered HydrogenM

eth

anol

Con

vers

ion

Temperature (°C)

Figure 9: Effect of the temperature on the performances of the reaction

Operating conditions: I=3, S/C=1.0, O/C=0.4,

P= 5 bar, Pp=1 bar

3/Pressure effect

1 2 3 4 50,46

0,48

0,50

0,52

0,54

0,56

0,58

0,60

xCH3OH

YH2

0,6

0,8

1,0

1,2

1,4

1,6

Recovered H

ydrogenMet

han

ol C

onve

rsio

n

Pressure (bar)

Figure 10: Effect of the pressure on the performances of the reaction

Operating conditions: I=3, S/C=1.0, O/C=0.4,

T=240°C, Pp=1 bar

1 2 3 4 50,62

0,63

0,64

0,65

0,66

0,67

0,68

1,0

1,2

1,4

1,6

1,8

xCH3OH

YH2

Recovered H

ydrogenMet

han

ol C

onve

rsio

n

Pressure (bar)

Figure 11: Effect of the Pressure on the performances of the reaction

Operating conditions: I=3, S/C=1.0, O/C=0.4,

T=260°C, Pp=1 bar

4/Sweep gas effect

1 2 3 4

0,42

0,44

0,46

0,48

0,50

xCH3OH

YH2 0,4

0,6

0,8

1,0

Recovered H

ydrogenMet

han

ol C

onve

rsio

n

Sweep gas |Factor (I)

Figure 12: Effect of sweep gas on the performances of the reaction

Operating conditions: S/C=1.0, O/C=0.4, T=240°C,

P= 1 bar, Pp=1 bar

1 2 3 40,50

0,52

0,54

0,56

0,58

0,60

0,62

0,64

0,66

0,68

xCH3OH

YH2

0,4

0,6

0,8

1,0

1,2R

ecovered HydrogenM

eth

anol

Con

vers

ion

Sweep gas Factor (I)

Figure 13: Effect of sweep gas on the performances of the reaction

Operating conditions: S/C=1.0, O/C=0.4, T=260°C,

P= 1 bar, Pp=1 bar

1 2 3 40,56

0,58

0,60

0,62

0,64

0,66

0,68

0,70

0,72

0,74

0,4

0,6

0,8

1,0

1,2

1,4

xCH3OH

YH2

Recovered H

ydrogenMet

han

ol C

onve

rsio

n

Sweep gas Factor (I)

Figure 14: Effect of sweep gas on the performances of the reaction

Operating conditions: S/C=1.0, O/C=0.4, T=280°C,

P= 1 bar, Pp=1 bar

CONCLUSION

The study on the autothermal reforming of methanol allows us to highlight

the effect of some operating parameters on the behavior of the process. A

mathematical model is developed by which a various parameters are simulated and

the performances are quantified (methanol conversion and the amount of recovered

hydrogen). The main results show that the performances of the reactor depend

strongly on the pair (S/C and O/C). At O/C=0.4 and S/C=1 good performances in term

of conversion and hydrogen recovered are noted.

BIBLIOGRAPHICAL REFERENCES[1] I.E. Wachs, R.I. Madix (1978) kinetic model of methanol oxidation over Cu/ZnO

catalyst. J Catal, Vol 53, Page 208

[3] T.L Reitz, P.L Lee, K.F Czaplewski, J.C Lang, K.E Popp, H.H Kung (2001) Time

Resolved XANES Investigation of CuO/ZnO in the Oxidative Methanol Reforming

Reaction. J Catal, Vol 199, Pages 193-201.

[2] J. Agrell, H. Birgersson, M. Boutonnet, I. Melián-Cabreara, R. M. Navarro, and

J. L. G. Fierro (2003) Production of hydrogen from methanol over Cu/ZnO catalysts

promoted by ZrO2 and Al2O3. J Catal, Vol 219, Pages 389-403.

[4] B.A. Peppley, J.C. Amphlett, L.M. Kearns, R.F. Mann (1999) Methanol steam

reforming on Cu/ZnO/ Al2O3 catalyst. Part 2: A comprehensive kinetic model, Appl

Catal A: Gen, Vol 179, Pages 31-49.

[5] J. R. Lattner, M. P. Harold (2005) Comparison of methanol-based fuel processors

for PEM fuel cell systems. Appl Catal B: Environ, Vol 56, Pages 149–169.

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