Structural Reactors for CO/CO2 Methanation · Design and examination of a novel, simplified packed...

KIT – Universität des Landes Baden-Württemberg und

nationales Forschungszentrum in der Helmholtz-Gemeinschaft

Institute for Micro Process Engineering, Gas and Multiphase Catalysis

www.kit.edu

Structural Reactors for CO/CO2 Methanation

Sarvenaz Farsi, Michael Belimov, Peter Pfeifer, Roland Dittmeyer

Energy Lab 2.0 meets Neo-Carbon Energy

Thursday 16.2.2017

Institute for Micro Process Engineering2 16.02.2017

Outline:

Power to gas technology

Theoretical fundamentals

Reactor design

Results

Catalyst stability tests

Reactor performance

Conclusion and Outlook

S.Farsi

Institute for Micro Process Engineering3 16.02.2017

Advanced Power-to-Gas Technology

S.Farsi

MINERVE (2012-2015)

„Management of Intermittent &

Nuclear Electricity by high efficiency

electrochemical Reactor for the

Valorisation of CO2 in flexible

Energies“

GDF Suez, CRIGEN, Paris

CEA, Grenoble

KIT, Karlsruhe

AGH, Cracow

Solvay (Rhodia), Lyon

Rationale:

High efficiency co-electrolyzer (90%)

CAPEX reduction due to the double function

of the co-electrolyzer (steam electrolysis and

RWGS to produce synthesis gas)

Higher global efficiency due to utilization of

the reaction heat of methanation

Process integration of an SOEC in

co-electrolysis mode with an

advanced methanation reactor

Institute for Micro Process Engineering4 16.02.2017

Theory: Methanation Fundamentals

CO – Methanation

CO2 – Methanation

Stro

ng

lyexo

the

rmic

!

Ni,Ru

Important side reactions

Water-Gas-Shift:

→ Influences CO/CO2-ratio and therefore kinetics

Boudouard-Reaction:

→ Problem: catalyst deterioration Loss of activity

S.Farsi

Ni, Ru

Institute for Micro Process Engineering5 16.02.2017

Theory: Thermodynamics

Methanation (15% CO, 10% CO2, 75% H2)

Coke formation at T<200°C & T> 450°C

S.Farsi

→Identification of a suitable window of operation for methanation of CO/CO2 mixtures.

Optimum operation regime : 200<T<450°C

Preferential methanation of CO

Cooling is imperative One step methanation

Institute for Micro Process Engineering6 16.02.2017

Lab Reactor System for Catalyst Studies

S.Farsi

Microstructured reactor

FeNi32Cr21AlTi-HC

1.5x9.3x60 mm (HxWxL)

Commercial Ni-catalyst (+SiC)

Cross flow cooling: Air @ 100 Nl/min

Institute for Micro Process Engineering7 16.02.2017

Results-Catalyst Stability TestsCO-Methanation

Temperature influence

Activity is a strong function of temperature

T increase results in better stability

S.Farsi

H2/CO variation

Slow deactivation at the beginning

H2/CO ratio 4-6: deactivation rate: -17%/h

H2/CO ratio 3: deactivation rate: -25%/h

The rest activity of the catalyst is still producing CH4

Institute for Micro Process Engineering8 16.02.2017

Results– Catalyst Stability TestsCO2-Methanation

Temperature variation

H2/C=4=const. (stoichiometric)

Slow deactivation compared to CO-meth

(deactivation rate: -0.11%/h)

Deactivation T-independent

linear decrease = 0 order, e.g. sintering

CO2 is a favourable feed gas for the reactor!

S.Farsi

H2/C-variation

H2/C=2-3

No obvious catalyst degradation within 20 h

Deactivation less sensitive to H2/C ratio!

Institute for Micro Process Engineering9 16.02.2017

Deactivation causes

BET

CO-meth. as example

Shift in pore size distribution

Surface area change 625363 m2

XRD

Fresh catalyst: dp 9.5-9.7 nm, used: 11.2-11.9 nm

NiC overlaps Ni and NiO signal

Surface carbon not detectable

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Institute for Micro Process Engineering10 16.02.2017

Conceptual Microstructured Reactor

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Geometry

Bed: 2 Slits W:5 cm, L:10 cm, H:0.2 cm

Slits filled with catalyst dp=0.2-0.6 mm

Cooling: 70 channels 500 x 500 µm

5 Heating cartridges (250 W each)

Institute for Micro Process Engineering11 16.02.2017

Reactor Design

Materials

FeNi32Cr21AlTi-HC (alloy 800H)

Operation

Heat management:

heat transfer fluid for cooling

electrical heating cartridges for pre-heating

Cooling in co-flow (counter-flow possible)

Cooling media: air, steam and water

Catalyst

5 g commercial Ni-based catalyst

diluted with SiC

mcat 10 times over design

S.Farsi

Institute for Micro Process Engineering12 16.02.2017

Results-Reactor Performance

Dynamic behavior

Conditions:

10% CO, 7% CO2, H2 72%, rest N2

Syngas throughput: 23 Nl/min, 6 bar, Feed T: 300°C

Temperature development in absence of cooling:

Temperature front movement with ~280 K/min

Max ΔT between reactor and catalyst bed: 80K

Hot spot formation ~520°C

After cooling→ quasi steady-state conditions:

t>7 min

Introduction of cooling 50 Nl/min (air, Tc,in=50°C)

No packed bed overheating!

M. Belimov, D. Metzger, P. Pfeifer. On the temperature control in a microstructured packed bed reactor for methanation of CO/CO2 mixtures. DOI 10.1002/aic.15461

S.Farsi

Institute for Micro Process Engineering13 16.02.2017

Results-Reactor Performance

Syngas throughput variation

15 Nl/min

Qr = 325 W

Tmax ~430°C

23 Nl/min

Qr = 519 W

Tmax~490°C

Cooling media variation

Air, Steam

Steam cooling capability is comparable to air

Less steam needed 15% (CP)

Conversion near to thermodynamic equilibrium achieved in all cases.

Question: Can hot spot be removed using water as coolant?

M. Belimov, D. Metzger, P. Pfeifer. On the temperature control in a microstructured packed bed reactor for methanation of CO/CO2 mixtures. DOI 10.1002/aic.15461

S.Farsi

Institute for Micro Process Engineering14 16.02.2017

Results- Reactor Performance

Cooling via water evaporation

8-12 g/min water (95-99°C)

Syngas Throughput:15 and 23 Nl/min

Stabilization using heating elements (HC)

Case a)

HC1(T1=460°C) & HC4 (T4=350°C) required

QHC/Qr ~ 10%

Natural state, hot spot covered

Case b)

HC1 (T1=360°C) required

QHC/Qr ~ 35%

Hot spot present!

M. Belimov, D. Metzger, P. Pfeifer. On the temperature control in a microstructured packed bed reactor for methanation of CO/CO2 mixtures. DOI 10.1002/aic.15461

What is limiting factor? BED OR COOLING SIDE?

CFD (Computational Fluid Dynamics) Study

S.Farsi

Institute for Micro Process Engineering15 16.02.2017

Conclusion

Insight into the catalyst deactivating operational conditions.

Design and examination of a novel, simplified packed bed microstructured

reactor for CO/CO2 mixtures with an input feed of 1-1.5 m3/h and various

coolant media (air, steam and water).

Proposing a model to control hot spot formation (<500°C, less deactivation)

which is necessary for stable operation by cooling with steam generation.

Almost full conversion (at equilibrium).

Thermal and conversion equilibration within a few minutes.

S.Farsi

Institute for Micro Process Engineering16 16.02.2017

Outlook

Comparison of the kinetic data with literature models.

More extensive kinetic analysis including transient operation and long-term

operational stability.

Optimization of the manufactured prototype regarding heat removal

(evaporation cooling).

Scale-up for higher throughputs (>100 kW methane).

S.Farsi

Institute for Micro Process Engineering17 16.02.2017

Energy Lab 2.0 at KIT-Plant Network

S.Farsi

Institute for Micro Process Engineering18 16.02.2017

Acknowledgement

S.Farsi

KIC InnoEnergy for funding of

MINERVE project

German Ministry for

Education and Research

(BMBF)

for funding of the Kopernikus-

Project P2X

For funding of the

Energy Lab 2.0

Thank you for your attention!