Structural Reactors for CO/CO2 Methanation · Design and examination of a novel, simplified packed bed microstructured reactor for CO/CO 2 mixtures with an input feed of 1-1.5 m3/h

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

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Advanced Power-to-Gas Technology

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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


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

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Ni, Ru


Theory: Thermodynamics

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

Coke formation at T<200°C & T> 450°C

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→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


Lab Reactor System for Catalyst Studies

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Microstructured reactor

FeNi32Cr21AlTi-HC

1.5x9.3x60 mm (HxWxL)

Commercial Ni-catalyst (+SiC)

Cross flow cooling: Air @ 100 Nl/min


Results-Catalyst Stability TestsCO-Methanation

Temperature influence

Activity is a strong function of temperature

T increase results in better stability

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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


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!

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H2/C-variation

H2/C=2-3

No obvious catalyst degradation within 20 h

Deactivation less sensitive to H2/C ratio!


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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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)


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

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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

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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?


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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!


What is limiting factor? BED OR COOLING SIDE?

CFD (Computational Fluid Dynamics) Study

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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.

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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).

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Energy Lab 2.0 at KIT-Plant Network

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Acknowledgement

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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!

Documents

Structural Reactors for CO/CO2 Methanation · Design and examination of a novel, simplified packed bed microstructured reactor for CO/CO 2 mixtures with an input feed of 1-1.5 m3/h