PPT-WM-3-Huebner- LAMNET-WS-Brasilia

8/2/2019 PPT-WM-3-Huebner- LAMNET-WS-Brasilia

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Dr.-Ing. Peter Hbner

LAMNET Workshop, Brasilia, Dec. 2 - 4, 2002

Research on the reforming of ethanol

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Reforming of Ethanol, LAMNET-Workshop, Brasilia

Introduction

- regenerative energy sources for hydrogen fuel cells

- motivation for ethanol as fuel

Reforming of fossil fuels

- allothermal reforming

- partial oxidation

- autothermal reforming

European Project: bioethanol reforming

- reformer and shift conversion device

- burner development

- catalyst screening

Summary, Outlook

CH3CH2OH

H2O

H2-rich gas


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Introduction regenerative energy sources for hydrogen fuel cells

1. Electrolysis of water with electricity

from regenerative sources like

- windenergy- hydropower

- solar energy

regenerative power sources:

until now neglegiblemarket penetration

2. Reforming of biogenic (CO2-neutral) fuels

- solid biomass (wood, wood pellets)

- biogas

- pyrolysis oil

- biogenic ethanol

bio-ethanol

- can be reformed

most easily

- is economically attractive

(see following slides)

motivation for ethanol

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Introduction: motivation for ethanol as fuel - economic potential

Preliminary estimation of worldwide market

penetration:

550 million tons per year in the transport sector (20

% of present consumption)

500 million tons per year for co-generation capacity(10 % of present capacity)

several hundred million tons per year in the

domestic market

200 million tons per year for the chemicals market

Source: Guiliano Grassi, Bioethanol - Industrial world perspectives in Renewable

Energy World, May-June 2000, p. 86 - 97

potential contribution of

ethanol to energy supply

is significant


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100

62,9

50

31,425

15,7

0

20

40

60

80

100

1980 1990 2000

cost in $/ barrelcost in EUROC/l

Cost reduction potent ial: the Brazilian example

Source: Jos Goldberg in Tagungsband zur Veranstaltung Biotreibstoffe, 22. Juni 1999, Rschlikon, Switzerland

1 Barrel = 159 liter

assumption: 1 Dollar = 1 Euro

Introduction: Motivation forethanol as fuel

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allothermal reforming

heat is transferred via a burner,

special burner design required

high hydrogen content of the

reformate

convective

heat transfer

Radiative

burner

Reforming reactor

400

600

800

1000

1200

Reformer

Off-gas

Off-gas burner

Temperature/ C

Reaction path

H2 75-78 Vol %

CO2 10-12 Vol%

CO 8-10 Vol %

CH4 2- 5 Vol%

H2O

25 % C of HC

75 % H2 O



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partial oxidation

2

HCO2N 2

CO2 (0,6-2 Vol%)CO (14-18 Vol%)CH4 (0 Vol%)N2 (43-52 Vol%)

O

H2 (24-30 Vol%)

Reforming reactor

400

800

1200

Reaction path

Temperature / C

1600

H

without catalystat 1300 C - 1400 C

good dynamic behaviour

simple construction

lowest hydrogen content

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autothermal reforming

heat is released in the

catalyst bed

quick start-up

good dynamic behaviour

temperature peak at

the reactor inlet

HCO2N2H2O

CO2 (8-10 Vol%)CO (9-11Vol%)CH4 (0,2-4 Vol%)N2 (48-52 Vol%)H2O

H2 (28-32 Vol%)

Reforming reactor

400

600

800

1000

1200

Temperature / C

Reaction path


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steam reforming of alcohols,

general equationCnH2n+1OH + (2n -1) H2O 3n H2 + n CO2

steam reforming of ethanol C2H5OH + 3H2O 6 H2 + 2 CO2 RH =

173,5 kJ/mol

endothermal cracking of ethanol C2H5OH + H2O 4 H2 + 2 CO RH = 255,9 kJ/mol

exothermal CO-conversion CO + H2O H2 + CO2 RH = -41,2 kJ/mol

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Partnership:

Fraunhofer ISE Reforming of bioethanol,CO-conversion

Co-ordination

Universtity of Duisburg Fine purification by PSA

Nuvera Fuel cell requirements,implementation and dissemination of the result s

Bioethanol as fuel for fuel cell vehicles and small scale stationaryapplications JOR3-CT97-0174

Summary of results: May, 2001


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European project:bioethanol reforming

Reformer- PEM fuel cellsystem with ethanol asfuel

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Reformer und CO-conversion device at Fraunhofer ISE

1

2

34

5

1. Water/ethanol pump

2. Reformer

3. HT-shift reactor

4. NT-shift reactor5. Gas cooling heat exchanger

European project: bioethanol reforming

Reformer

700 - 1000C

HT-shift

350-400C

NT-shift

180-220C


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Experimental set-up:

Reformer:

Height: 150 mm

Diameter: 121 mm

Catalyst Volume: 600 cm3

Burner:

Height: 150 mm

Diameter: 81 mm


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European project: advantages of the porous burnerbioethanol reforming

high effective heat conduction of the pore material( 60 - 100 higher then the effective heat conduction of gas)

large combustion reaction zone( flame burner reaction zone thickness 1 mm)

lower temperature in the reaction zone

homogeneous temperature profile

lower NOx- and CO-emission

high flame velocity in the pore medium without flame instability

( 8 - 10 higher then a flame burner)

large performance modulation range 1:20 ( flame combustion 1:3)


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European project: catalyst screeningbioethanol reforming

name composition sign. operation range

nickel-cat. nickel on Al2O3 Ni treact ion < 800

ruthenium-cat. ruthenium on Al2O

3Ru t

react ion< 800

plat inum cat . platinum on Al2O3 Pt treact ion < 800

palladium cat . palladium on Al2O3 Pd treact ion < 800

Perovskite-cat . lanthanum, manganese, cobalt , st ront ium Pe treact ion < 800

nickel-platinum-cat. nickel; platinum on Al2O3 PtNi treact ion < 800

nickel-palladium-cat. nickel; palladium on Al2O3 NiPd treakt ion < 800

investigation parameters

Temperature: 600; 700; 800 C

steam to carbon ratio: 2; 3; 4

pressure: 2; 5; 9 bar

gas hourly space velocity: 2000 - 6500 sleducts/(lcath)

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Operation load 38 115 [%]

Porous burner temperature 910 1100 [C]

Temperature of the fixed catalyst bed 720 - 800 390 - 880 [C]

Pressure 7,3 7,3 [bar]

S/C ratio 4 4 [moleH2O/atomC]

Reformer ethanol inlet stream 3,45 10,36 [mole/h]

Enthalpy stream of the ethanol 1,19 3,57 [kW]

Product gas stream 42,89 128,9 [mole/h]

Hydrogen stream of the product gas 14,90 44,63 [mole/h]

Enthalpy stream hydrogen reformer 1,00 3,00 [kW]

Burner hydrogen stream 7,5 22 [lN/min]

Enthalpy stream hydrogen burner 1,35 3,96 [kW]

Burner exhaust stream 23,7 64,3 [lN/min]

operation parameters of the Fraunhofer ISE-ReformerEuropean project:bioethanol reforming


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catalyst screening

T = 700 CS/C = 4

selection of Ni-catalyst

0,5

0,6

0,7

0,8

0,9

1

2 3 4 5 6 7 8 9

pressure [bar]

H2-yield[(mole/h)H2

/(mole/h)

Eth.]

Ni Pd Pt Ru Pe PtNi NiPd

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Ni catalyst

T = 700 Cp = 2 bar

influence of S/C

H2

CH4

CO2

CO

13,9

10,9

8,7

14,0

16,4

18,4

2,4

1,0

0,5

68,5

70,5

71,2

0,0 10,0 20,0 30,0 40,0 50,0 60,0 70,0 80,0

2

3

4

S/C-ratio

molar fractionl [%,dry]


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10,3

8,8

7,7

17,4

18,5

19,3

10,3

7,3

4,3

61,5

65,1

67,7

0,0 10,0 20,0 30,0 40,0 50,0 60,0 70,0 80,0

2

3

4

S/C-ratio

molar fraction [%,dry]

H2

CH4

CO2

CO


Ni catalyst

T = 700 Cp = 9 bar

influence of S/C

higher pressuredue to PSA

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HTS

Fe-oxide-catalystGHSV = 4000/h

S/C = 4

377 374 372

422 424 425

402 402 403

2,72

2,03

2,23

0

50

100

150

200

250

300

350

400

450

2 5 9

pressure [bar]

temperature[C]

0

0,5

1

1,5

2

2,5

3

COcontent[

mole%]

temperature top temperature middle temperature bottom CO content


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184

173 175

193 195196

177 177184

0,0860,087

0,135

0

50

100

150

200

2 5 9

pressure [bar]

temperature[C]

0,00

0,02

0,04

0,06

0,08

0,10

0,12

0,14

CO

content[mole%]

temperature top temperature midd le temperature bottom CO content

LTS

Cu/Zn-catalystGHSV = 4000/hS/C = 4

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45,442,4 40,5

38,5

41,7 43,4

10,313,6 14,9

4,71,2 0,1

1,1 1,1 1,2

0

5

10

15

20

25

30

35

4045

50

gascomposition[mole%

]

Reformer HT-shif t LT-shif t

CH4

CO

CO2

H2

H2O

CH4 CO CO2 H2 H2OEuropean project:bioethanol reforming

Results of reformer andCO-shift device

S/C = 4p = 9 bar

With CO fine purification:Reformate suitable forPEM- fuel cell


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Hydrogen generation from biogenic ethanol is attractive due to

- good availability,

- competitive costs,

- easy realisation of reforming process

Research of bioethanol reforming at Fraunhofer ISE:

- development of a compact steam reformer with preheating

of liquid reformer feedstream (with burner exhaust gas) and

of the air for the burner (with the reformer product gas)

- development of a porous burner with stable combustion for offgas,

methane, or ethanol

- optimisation of heat losses and performance

Outlook:

- reduction of volume and weight of the reforming unit

- reduction of start-up time

- further improvement of performance

- cost reduction

- longtime-operation to show catalyst stability

European project:

bioethanol reformingSummary

Summary

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Outlook

5 kW Fuel processor unitfor stationary electricitygeneration

Source: Nuvera Fuel Cells Europe, Milan, methanol reformer


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Thank you very much for your attention!

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PPT-WM-3-Huebner- LAMNET-WS-Brasilia