Søren Højgaard Jensen, Senior researcher at DTU Energy · Søren Højgaard Jensen, Senior researcher at DTU Energy . ... DTU Energy, Technical University ... Total energy demand

Methanol Production from biomass and intermittent power

Lund University, March 17th 2015 Søren Højgaard Jensen, Senior researcher at DTU Energy

DTU Energy, Technical University of Denmark

• About DTU Energy

• Thermochemical conversion of biomass to MeOH

• Electrolyser Cells

• Solid Oxide Cell

• Dynamic Operation

• Cost Estimation

• Conclusion

Content


• About 250 employees • Sustainable technologies for energy conversion and storage

• Focus on

– R&D – Innovation – Education

DTU Risø Campus DTU Lyngby Campus

Department of Energy Conversion and Storage


Department of Energy Conversion and Storage

Fuel cells (SOFC, HT-PEMFC, LT-PEMFC)

Electrolysis (SOEC, AEC)

Solar cells (Polymer, CZTS)

Batteries

Membranes for oxygen separation

Magnetocaloric cooling and heat pumps

Thermoelectric generators

Flue gas purification

Superconductors

Technologies


Methanol Production from biomass and intermittent power

GreenSynFuels Report: http://www.hydrogennet.dk/groennesynfuels/

-Thermochemichal Synthesis

Conventional Cu/ZnO-Al2O3 methanol catalysts operates at 200 °C - 300 °C at 45 – 60 bar

CO2 + 3H2 = CH3OH + H2O 41 kJ/mole CO + 2H2 = CH3OH 91 kJ/mole M = (H2 – CO2)/(CO + CO2) ≅ 2

http://www.hydrogennet.dk/groennesynfuels/


6 18 March 2015

Type electrolyte Alkaline Acid Polymer Solid oxide

Electrolyte NaOH or KOH

H2SO4 or H3PO4

Polymer Ceramic

Charge carrier OH- H+ H+ O2-

Reactant H2O H2O H2O H2O and/or CO2

Electrodes Ni Graphite with Pt + polymer

Graphite with Pt + polymer

Ni + ceramics

Temperature 80 -150 °C 140 - 180 °C 60 - 80 °C 700 - 900 °C

Various Types of Electrolysis Cells


7 18 March 2015

Methanol Dream Cell: Stable at 200 – 300 °C and 45-60 bar

H+

e- e-H2O

O2, H2O

CO2

CH3OH, H2O, CO2, …

H+

e- e-H2O

O2, H2O

CO2


H+

e- e-H2O

O2, H2O

CO2


Solid or immobilized electrolyte, e.g. H+ conductor

Gas diffusion electrodes

Porous cathode Porous anode


The Norby gap

From T. Norby, Solid State Ionics, 125 (1999) 1


Bridging the Norby gap: HT-PEM Electrolyser Cell

1.20

1.30

1.40

1.50

1.60

1.70

1.80

0 200 400 600 800 1000

Po

ten

tial

[V

]

Current density [mA cm-2]

Ambient pressure, PFSA membrane (Aquivion) doped with H3PO4

130ºC

Source; J.O.Jensen , DTU Kemi

iTN E500 150

mA/cm2 1.625 V

• PBI not stable • Ta coated steel felt


Bridging the Norby gap: HT-Alkaline Electrolyser Cell

• Electrolyte: -aqueous KOH immobilized in a

porous structure • Gas diffusion electrodes: - porous Nickel, Raney-Nickel

High temperature and pressure alkaline electrolysis

F. Allebrod, C. Chatzichristodoulou, M. Mogensen, submitted paper and filed patent application


Bridging the Norby gap: HT-Alkaline Electrolyser Cell

F. Allebrod, C. Chatzichristodoulou, M.B. Mogensen, J. Power Sources, 229 (2013) 22, and in Proc. of this meeting, paper A0705.

Performance of cells with immobilized KOH(aq.) at 40 bar


The Solid Oxide Cell



Ni/YSZ support & current collector

Ni/YSZ electrode YSZ electrolyte

LSM-YSZ electrode

LSM current collector

LSM = (La0.75Sr0.25)0.95MnO3 YSZ = Zr0.84Y0.16O1.92


Solid Oxide Electrolysis Cell

H2O (and CO2) H2 (and CO)

O2

O2

H2 (and CO)

+

−

+

−

H2O (and CO2)

Solid Oxide Fuel Cell

1.3 V

0.8 V


Electrode Reaction Kinetic

H 2 + O -- H 2 O + 2e -

½O 2 + 2e - O --

νf

νb

νf

νb



• Interconnect is usually ferritic stainless steel, ~22 % Cr with a number of small additives. Several commercial (or semi-commercial) steels are available.

• Gas sealing between cells and interconnect is most often a suitable SiO2 based glass


0

50

100

150

200

250

300

0 100 200 300 400 500 600 700 800 900 1000

Temperature (ºC)

Ener

gy d

eman

d (K

J/m

ol)

0.00

0.26

0.52

0.78

1.04

1.30

1.55

1/(2

·n·F

) · E

nerg

y de

man

d (V

olt)

Liqu

id

Gas

H2O → H2 + ½O2

Total energy demand (Hf)

Electrical energy demand (Gf)

Heat demand (TSf)

Steam Electrolysis Thermodynamics

E cel

l = E

tn

Gas 1 bar

50 bar


Steam Electrolysis at Elevated Pressure

Experimental data,

DTU Energy


Electrode Reaction Kinetic

H 2 + O -- H 2 O + 2e -

½O 2 + 2e - O --

νf

νb

νf

νb


Polarization Ranges for State-of-the-art H2O Electrolysis Cells

Eth,water and Eth,steam are the thermoneutral voltages. Erev is the reversible voltage at standard state. C Graves, SD Ebbesen, M Mogensen, KS Lackner, Renew. Sustain. Energy Rev., 15 (2011) 1


Fluctuating Electricity Prices

Spot market electricity prices [DK-West] from 2006 to 2013 sorted hour-by-hour, lowest prices first

SH Jensen, et al. Energy & Environmental Science. Under review


SOEC Operating Strategy


Two operating strategies 1. Always at optimal H-C ratio for the synthesis step 2. SOEC operates at 1/3 of nominal power at high electricity prices

(generates enough O2 for gasification)



Methanol Production Cost - CAPEX




Methanol Production Cost - OPEX




Methanol Production Cost Estimations





Dynamic Operation of a Solid Oxide Cell

C Graves, SD Ebbesen, SH Jensen, SB Simonsen, M Mogensen. Nature Materials 14 (2015) 239


Cell vs. Stack stability


Conclusion

• Methanol Production from Biomass can be significantly boosted by H2O electrolysis using intermittent power

• MeOH production prices can be lowered using the above strategy with SOECs, but not dramatically unless

– A: SOEC lifetime is increased beyond 5 year, or – B: The SOEC cost is reduced

• Other types of cells could potentially emerge which can operate

around 200 – 300 °C and 20-60 bar. This could lead to lower costs because of

– A: Possibility for integrated Methanol catalyst – B: Lower costs for auxiliary components


Acknowledgement

• Thank you for your attention

Documents

Søren Højgaard Jensen, Senior researcher at DTU Energy · Søren Højgaard Jensen, Senior researcher at DTU Energy . ... DTU Energy, Technical University ... Total energy demand