produktion af syntetisk naturgas fra vedvarende … · koch, frank graf, siegfried bajohr, rainer...

DEPARTMENT OF ENGINEERING

31 JANUARY 2018 PHD STUD.

IDA CHRISTIAN DANNESBOEAARHUSUNIVERSITY

PRODUKTION AF SYNTETISK NATURGAS FRA VEDVARENDE ENERGIaka: solving global climate change

IDA CHRISTIAN DANNESBOE

31 JANUARY 2018 PHD STUD.DEPARTMENT OF ENGINEERING

AARHUSUNIVERSITY

LIDT OM MIG

Christian Dannesboe [email protected]

Aalborg Universitet

Civilingeniør i Kemi (2007)

Shell Raffinaderiet Fredericia

Model Koordinator(2007)

Ingeniørhøjskolen Aarhus

Adjunkt (2011)

Aarhus Universitet ASE

Lektor (2013)

• Proces Design

• Proces Optimering

• Reguleringsteknik

Frikøbt til el-opgraderet biogas 2015-2019

mailto:[email protected]



AARHUSUNIVERSITY

HVEM ER JEG

Ingeniør

• Glad for gode ideer

• Glad for tal

Nøglebegreber

• Fra teori til praksis

• Hvad kan vi måle?

• No bullshit

Jeg elsker at afprøve ideer og opsende prøveballoner



AARHUSUNIVERSITY

FOULUM BIOGAS FACILITY

Biogas produced from manure

Production of ~240 Nm3/h

Biogas is 40% CO2

(Only 60% of the biogas has value)



AARHUSUNIVERSITY

FOULUM BIOGAS FACILITY



AARHUSUNIVERSITY

PROGRAM

18:00 Introduction to Power-to-gas

19:00 Dinner + guided tour

19:20 Dinner + guided tour

20:00 Questions



AARHUSUNIVERSITY

POWER TO GAS

Idea: Convert electricity to gas

Enables:

• Cheap large scale energy storage

• Pipeline and vessel distribution

• Green gas compatible with existing technology

Economic drivers and motives:

• Renewable electricity price is volatile (peak shaving)

• Grid balancing (seasonal variation and grid stability)

• Political independence

• Solving global climate change



AARHUSUNIVERSITY

TECHNOLOGY

Electrolysis enables Power-to-Hydrogen

Available electrolysis technologies

• Alkaline electrolysis

• PEM electrolysis

• SOEC electrolysis

Challenges with hydrogen

• Hydrogen is hydrogen

• Energy intensive compression

• As a gas it has low energy density

Source Lower heating value

1 Nm3 Hydrogen 3.00 kWh

1 Nm3 Methane 9.97 kWh

1 Nm3 Propane 25.9 kWh

http://www.h2data.de/



AARHUSUNIVERSITY

ELECTROLYZERS

Source:

Electrocatalysts for the generation of

hydrogen, oxygen and synthesis gas

Progress in Energy and Combustion

Science, Vol 58 (2017) 1–35

Foteini M. Sapountzi, Jose M. Gracia,

C.J. (Kees-Jan) Weststrate,

Hans O.A. Fredriksson, J.W. (Hans)

Niemantsverdriet

H2O → H2 +½O2

Net reaction:



AARHUSUNIVERSITY

ELECTROLYZERS

Alkaline electrolysis PEM electrolysis Solid Oxide electrolysis

Development Commercial Commercial Lab. scale

Largest plants (2016) 750 Nm3/h

~2.7 MW

450 Nm3/h

~1.6 MW

-

Cell temperature 40 – 90 °C 20 – 100 °C 800 – 1000 °C

Cell voltage 1.8 – 2.4 V 1.8 – 2.2 V 0.9 – 1.3 V

Power consumption (current) 5.4 – 8.2 kWh/Nm3 4.9 – 5.2 kWh/Nm3

Power consumption (future) 4.3 – 5.7 kWh/Nm3 4.1 – 4.8 kWh/Nm3 3.0 kWh/Nm3

Advantages Highest capacity

Low plant cost

Long plant lifetime

No corrosive substance

Small plant size

High pressure operation

High electrical efficiency

Integration of waste heat

Disadvantages Large plant size

High maintenance cost

High plant cost

Fast degradation

Limited long tern stability

Not suited to fluctuations

Expensive

Source:

Renewable Power-to-Gas: A

technological and economic review

Renewable Energy

Vol 85, Jan. 2016, 1371-1390

Manuel Götz, Jonathan Lefebvre,

Friedemann Mörs, Amy McDaniel

Koch, Frank Graf, Siegfried Bajohr,

Rainer Reimert, Thomas Kolb

Lower heating value

Hydrogen 3.00 kWh/Nm3



AARHUSUNIVERSITY

ENERGY NEEDED TO SPLIT WATER

Source:

Thermodynamic Considerations for

Thermal Water Splitting Processes

and High Temperature Electrolysis,

Proceedings of the 2008

international Mechanical

Engineering Congress and

Exposition, Boston Massachusetts,

USA, 2008

J. E. O’Brien

Data originate from:

Hydrogen production by high

temperature electrolysis of water

vapour

International Journal of Hydrogen

Energy, Vol 5 (1980) pp. 55-63

W. Doenitz, R. Schmidberger, E.

Steinheil, R. Streicher

∆𝐺𝑠𝑝𝑙𝑖𝑡 = ∆𝐻𝑠𝑝𝑙𝑖𝑡 − 𝑇∆𝑆𝑠𝑝𝑙𝑖𝑡



AARHUSUNIVERSITY

SUMMERY

Hydrogen is the key molecule that allows conversion of electricity to gas

The best commercial units available deliver 55-60 % electrical efficiency.

Technological improvements could push this towards 70 % in the near future.

SOEC is the only technology to provide 100 % efficiency, but is not commercially available

Examples of electrolyzes in Denmark..



AARHUSUNIVERSITY

BIOCATPROJECT

Source:

Hydrog(e)nics

http://www.hydrogendays.cz/2016

/admin/scripts/source/presentation

s/PL%2005_%20Denis%20Thomas_

HDs2016.pdf

Alkaline electrolysis:

200 Nm3/h using 1 MW power

5 kWh/Nm3 hydrogen

Hydrogen used to produce methane

using bio catalyst (archaea)

http://www.hydrogendays.cz/2016/admin/scripts/source/presentations/PL 05_ Denis Thomas_HDs2016.pdf



AARHUSUNIVERSITY

HYBALANCE

Source:

Hydrog(e)nics

http://www.hydrogendays.cz/2016

/admin/scripts/source/presentation

s/PL%2005_%20Denis%20Thomas_

HDs2016.pdf

PEM electrolysis:

230 Nm3/h using 1.2 MW power

5.2 kWh/Nm3 hydrogen

Grid stability

Industrial customer for H2 and O2

http://www.hydrogendays.cz/2016/admin/scripts/source/presentations/PL 05_ Denis Thomas_HDs2016.pdf



AARHUSUNIVERSITY

ELOPGRADERET BIOGAS

SOEC electrolysis:

16 Nm3/h using 48 kW power

3.0 kWh/Nm3 hydrogen

Hydrogen used to produce

methane using solid catalyst.

Foulum, Denmark (construction in 2016)

BioSNG ProjectOBJECTIVES

• Design, engineer and construct a pilot scale power-to-gas facility

• Demonstrate synergies between catalytic methanation and SOEC electrolysis

• Demonstrate technology to produce pipeline quality synthetic natural gas from raw biogas

• The produced gas should be available to the transmission distribution grid (40 bar)

SOLUTION

• 2x SOEC cores from Haldor Topsøe with all peripherals to produce 16 Nm3/h H2.

• Power: 50 kW

This project receives financial support from EUDP



AARHUSUNIVERSITY

HYDROGEN AS A GREEN FUEL

Hydrogen is not the ideal green fuel

• Low energy density

• Aggressive behavior in a turbine

Only small percentage can be allowed in the existing gas grid (2 – 10 %)

Pure hydrogen for road transport is gaining acceptance

• Compression to 700 bar is the norm

• Expensive storage locations

• Filling stations struggle with compressor failures

• High power consumption by compression (around 10%)



AARHUSUNIVERSITY

METHANATION TECHNOLOGY

Methanation is the synthesis of CH4 from hydrogen and CO or CO2

Reactions are

• Highly exothermal

• Thermodynamically favorable

• Limited by kinetics (require catalyst)

• A possible source of water/steam

∆𝐻𝑟° = −206.3 𝑘𝐽

𝑚𝑜𝑙

∆𝐻𝑟° = −165.1 𝑘𝐽

𝑚𝑜𝑙

𝐶𝑂 (𝑔) + 3 𝐻2 (𝑔)𝑐𝑎𝑡.

𝐶𝐻4 (𝑔) + 𝐻2𝑂 (𝑔)

𝐶𝑂2 (𝑔) + 4 𝐻2 (𝑔)𝑐𝑎𝑡.

𝐶𝐻4 (𝑔) + 2 𝐻2𝑂 (𝑔)

From a hydrogen perspective

COCH4 ∆𝐻𝑟° = −69 𝑘𝐽

𝑚𝑜𝑙

CO2CH4 ∆𝐻𝑟° = −41 𝑘𝐽

𝑚𝑜𝑙

H2O(l)H2O(g) ∆𝐻𝑣𝑎𝑝. = 41 𝑘𝐽

𝑚𝑜𝑙



AARHUSUNIVERSITY

TREMP™ PROCESS

𝐶𝑂 (𝑔) + 3 𝐻2 (𝑔)𝑐𝑎𝑡.

𝐶𝐻4 (𝑔) + 𝐻2𝑂 (𝑔) ∆𝐻𝑟° = −206.3 𝑘𝐽

𝑚𝑜𝑙

700°C 600°C 400°C 250-300°C

TREMP is a trademark of Haldor Topsøe



AARHUSUNIVERSITY

REACTION EQUILIBRIUM

𝐶𝑂2 (𝑔) + 4 𝐻2 (𝑔)𝑐𝑎𝑡.

𝐶𝐻4 (𝑔) + 2 𝐻2𝑂 (𝑔) ∆𝐻𝑟° = −165.1 𝑘𝐽

𝑚𝑜𝑙

Product favored by

• High pressure

• Low temperature



AARHUSUNIVERSITY

UPGRADING OF CO2 IN BIOGAS

Component Amount

CH4 60%

CO2 40%

H2S ~1000ppm

Water saturated

Component Amount

CH4 97,2% (min)

CO2 2,5% (max)

H2S 5 ppm (max)

Water nill

The digestion of organic waste produce biogas. A gas rich in CO2.

Biogas Pure methane Natural gas

Component Amount

CH4 100%

CO2 0%

H2S 0 ppm

Water nill



AARHUSUNIVERSITY

SYNERGY WHEN UPGRADING BIOGAS

The methane in the biogas serves as an excellent heat carrier in the reactor.

Heat per cube ( kJ

m3K)

H2O 1.552

CH4 1.483

N2 1.212

Ar / He 0.864

CH4 + CO2 + H2 CH4 + H2O Adiabatic temperature

0 4 16 4 8 724 °C

6 4 16 10 8 489 °C

Hydrogen

BioSNG

Water

Biogas60% Methane

40% CO2

100% Methane

0% CO2

100% Water



AARHUSUNIVERSITY

EQUILIBRIUM SHIFT?

Biogas 60%/40%

95%

96%

97%

98%

99%

100%

0% 50% 100% 150% 200%

Re

ac

tio

n y

ield

Surplus methane added as reactant

Sabatier reactor yield

Having surplus methane affects the reaction equilibrium

Effect of surplus methane is minimal

𝐶𝑂2 + 4 𝐻2𝑐𝑎𝑡𝑎𝑙𝑦𝑠𝑡

𝐶𝐻4 + 2 𝐻2𝑂

Reaction yield as simulated in

Aspen Plus.

Simulation based on a Gibbs

reactor at 300°C and 20 bar.



AARHUSUNIVERSITY

DESIGN CONCEPT

Boiling water reactor



AARHUSUNIVERSITY

MODIFIED DESIGN



AARHUSUNIVERSITY

REACTOR FIGURES

Position CH4 CO2 N2 H2

Biogas 56 43 1 0

Exit 1st stage 94.58 0.27 0.91 4.23

Product gas 97.69 0.00 0.95 1.36

𝐶𝑂2 + 4 𝐻2𝑐𝑎𝑡𝑎𝑙𝑦𝑠𝑡

𝐶𝐻4 + 2 𝐻2𝑂



AARHUSUNIVERSITY

SANKEY DIAGRAM



AARHUSUNIVERSITY

PLANT LAYOUT

Hydrogen

Carbon dioxide

Methane

24%

16%60%



AARHUSUNIVERSITY

FUNDING

External funding by EUDP: 5.3 mio € (2013-2017)

Plant design and engineering by Haldor Topsøe



AARHUSUNIVERSITY



AARHUSUNIVERSITY

GAS QUALITY

New quality strategy:• No planned hydrogen surplus

• CO2 leak accepted

• Significant improvement

Note:Issue with Agilent software, 80

hours of gas data found but not yet

extracted.

Currently 13400 samples

Not included 1600 samples

Total runtime is 750 h.



AARHUSUNIVERSITY

SOEC STARTUP

0

20

40

60

80

100

120

140

160

180

200

0

100

200

300

400

500

600

700

800

16:00 18:00 20:00 22:00 00:00 02:00 04:00 06:00 08:00 10:00 12:00 14:00 16:00

Vo

lt o

r A

mp

per

15

0 c

ells

Deg

. C

Hour

Out Preheater

In Stacks

Out Stacks

Volt

Amps

Volt

Current

Temperatures

Heat up of SOEC unit

from cold 10-11 hours,

but full production

on/off within seconds



AARHUSUNIVERSITY

SUMMARY

Combining SOEC with catalytic methanation of CO2 shows clear synergies:

• Steam formed by the Sabatier reaction covers half the water need

• With a boiling water reactor, the SOEC steam requirement is supplied as excess heat

• Upgrading of CO2 in biogas simplifies process design and heat management

For a green future:

• Biogas potential DK: 40 PJ

• If upgraded by SOEC: 67 PJ

• NG used in household, industry and service: 76 PJ



AARHUSUNIVERSITY

One never notices what has been done; one can

only see what remains to be done.

- MARIE CURIE

AARHUSUNIVERSITY

produktion af syntetisk naturgas fra vedvarende … · koch, frank graf, siegfried bajohr, rainer...

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