E.-A. Reinecke , S. Kelm, S. Struth, Ch. Granzow, U. Schwarz*

Forschungszentrum Jülichin der Helmholtz-Gemeinschaft

E.-A. Reinecke, S. Kelm, S. Struth, Ch. Granzow, U. Schwarz*

• Catalytic recombiners

• Design studies

• Conclusions

Design of catalytic recombiners for safe removal of hydrogenfrom flammable gas mixtures

Institute for Energy Research - Safety Research and Reactor Technology (IEF-6)

*Institute for Reactor Safety and Reactor Technology RWTH Aachen University

2nd International Conference on Hydrogen SafetySan Sebastian, September 11-13, 2007


Research on hydrogen safety at FZJ

• Focus: H2 removal by means of catalytic recombiners (PAR)

• Hydrogen laboratory with 3 REKO facilities experimental PAR studies

• Service of Dpts. Analytical Chemistry (ZCH) and Technology (ZAT) catalyst development

• Simulation of recombiner behaviour code development

Severe Accident Research NETwork (NoE)

(EURATOM) Safety of Hydrogen as an Energy Carrier (NoE)


Why recombiners ?

• Device removing hydrogen from oxygencontaining atmosphere (e.g. air) in thepresence of a catalyst (e.g. Pt, Pd) hydrogen sink

• Today application in areas where venting is not sufficient/possible- NPP containment (H2 formation during core melt accident)- BWR cooling circuit (H2 formation in operation)- submarines (H2 released from the propulsion system)- batteries (‚HydroCaps‘)

specific applications

• Future use of hydrogen in ‚any‘ surrounding may lead to anextended area of application for recombiners


catalystsheets

Siemens design

Catalytic recombiners in NPP

• Severe accident in LWR H2 release

• Formation of flammable H2/air mixture inside containment

• Installation of catalytic recombiners

0

50

100

150

200

0 3 6 9

H2 concentration in vol.%

conversion rate related to theinlet cross-section

source: Siemens PAR information

model:

FR90-1500

FR90-320

model:FR90-320

FR90-960

source:BMC experiments

H2 c

on

ve

rsio

n r

ate

in

n

-m³/

(m²h

)


PAR principle

inletH2 + air

outletair + H2O

catalystH2 + ½ O2 H2O + heat

inletH2 + air

outletair + H2O

catalystH2 + ½ O2 H2O + heat

chimneybuoyancy effect

natural convection application

forced flow application


Catalyst temperatures - major drawback

0

100

200

300

400

500

600

700

800

0 1 2 3 4 5 6

inlet hydrogen concentration / vol.%

max

. ca

taly

st

tem

per

atu

re /

°C

conventional ignition temperature

plate-type catalyst

mesh-type catalyst


Challenge

Passive system temperature control • no direct influence on the process parameters

(flow rate, inlet mixture composition, active temperature control)• no active cooling

Further demands• resistance against catalyst poisoning/deactivation• environmental influences depending strongly on application

self-regulating system


Design studies


• Design studies

• Conclusions


Self-regulating system

General approach• local limitation of the catalytic reaction

• passive cooling of the catalyst elements

catalyst design, support design

geometrical design, cooling elements


Self-regulating system

General approach• local limitation of the catalytic reaction

• passive cooling of the catalyst elements

Basic element types (catalyst - support)• high performance catalyst - large surface support• adapted performance catalyst - large surface support• high performance catalyst - passive cooling support

HPC-LS

APC-LS

HPC-PC

catalyst design, support design

geometrical design, cooling elements


Experimental Facilities

• Experimental studies on the operational behaviour under well defined conditions



Vorbere itungsraum213f

Rechnerwarte213c

F lur213b

M eßraum 1213e

M eßraum 2213d

RE KO -2

RE KO -1

ELBA

RE KO -3

Operator

REKO-1

JuNet

ISR 073

Eth

erne

t-H

ub

E thernet-Hub

ProPlus

REKO-2

Pro

REKO-3

DeltaVCTRL-2

DeltaVCTRL-1

AS 1.1

AS 2.1

AS 1.2

VS 1 VS 2

JuNet

ISR 011

JuNet

ISR 076

H 21

H 22

1

1

2

2

W erkbank 2

G aslager

We

rkb

ank

1

Ga

süb

erw

.Abzug

Heizofen

Waage

Schrank 4

Schränke 8-11

Schränke 5-7

E-Verte iler 1UV 7

Schrank 3

Schrank 2 Schrank 1

Kran K21000 kg

Kran K4250 kg

Kran K3125 kg

6,30 m

h = 4,50 mA = 38,2 m²V = 172 m³

h = 4,50 mA = 20,6 m²V = 93 m³

h = 4,50 mA = 20,6 m²V = 93 m³

3,70 m

2,60 m

2,30 m

3,90 m6,90 m

4,00 m 4,00 m

4,0

0 m

5,1

5 m

5,1

5 m

2,0

0 m

3,50

m

Anb

au

3,5

x 4,

0 m

²

3,15

m

E 6

E 10 E 9

E 8


Vorbere itungsraum213f

Rechnerwarte213c

F lur213b

M eßraum 1213e

M eßraum 2213d

RE KO -2

RE KO -1

ELBA

RE KO -3

Operator

REKO-1

JuNet

ISR 073

Eth

erne

t-H

ub

E thernet-Hub

ProPlus

REKO-2

Pro

REKO-3

DeltaVCTRL-2

DeltaVCTRL-1

AS 1.1

AS 2.1

AS 1.2

VS 1 VS 2

JuNet

ISR 011

JuNet

ISR 076

H 21

H 22

1

1

2

2

W erkbank 2

G aslager

We

rkb

ank

1

Ga

süb

erw

.Abzug

Heizofen

Waage

Schrank 4

Schränke 8-11

Schränke 5-7

E-Verte iler 1UV 7

Schrank 3

Schrank 2 Schrank 1

Kran K21000 kg

Kran K4250 kg

Kran K3125 kg

6,30 m

h = 4,50 mA = 38,2 m²V = 172 m³

h = 4,50 mA = 20,6 m²V = 93 m³

h = 4,50 mA = 20,6 m²V = 93 m³

3,70 m

2,60 m

2,30 m

3,90 m6,90 m

4,00 m 4,00 m

4,0

0 m

5,1

5 m

5,1

5 m

2,0

0 m

3,50

m

Anb

au

3,5

x 4,

0 m

²

3,15

m

E 6

E 10 E 9

E 8


REKO-1• Experimental studies

on reaction kinetics in catalyst elements

• Substrates applied- steel meshes- ceramic bodies


REKO-1 test facility

gas analysis

pyrometer

inlet

catalyst samples

thermocouples


Realisation of large surface support

Large surface support• high performance catalyst• adapted performance catalyst

Pt - washcoat

Pt - electroplated


Performance of HPC and APC

H2 concentration / vol.%

cata

lyst

tem

per

atu

re /

°C

1.0 m/s

0

200

400

600

800

1000

1200

0 5 10 15 20 25

HPC-LS

APC-LS


Realisation of APC-LS - new approach

APC-LS• adapted performance catalyst• large surface support

Pt-nano-particles / metal oxide matrix

Ceramic cell support


Performance of new HPC-LS approach

250

300

350

400

450

500

0 2 4 6 8 10

H2 concentration / vol.%

ca

taly

st

tem

pe

ratu

re /

°C

50

60

70

80

90

100

eff

icie

nc

y /

%

catalyst temperature

efficiency

flow rate: 0.25 m/ssupport: plate-typecatalyst: n-Pt MO


Realisation of passive cooling

Passive cooling support• approach: passive cooling by

means of heatpipes


Performance of HPC-PC

diameter 8 mm

0,5 m/s0

100

200

300

400

500

600

0 2 4 6 8 10 12

hydrogen concentration / vol.%

ca

taly

st

tem

pe

ratu

re /

°C

HPC-PC

HPC

Passive cooling support• approach: passive cooling by

means of heatpipes


Basic features of catalyst designs

HPC-LS

APC-LS

HPC-PC

type

high performance

adapted performance

high performance

large surface

large surface

passive cooling

catalyst support

~ 2 vol.%

< 1 vol.%

~ 2 vol.%

start behaviour

~ 70 %

> 90 %

~ 10 %

efficiency/ element

unlimitedheating uplimited to~ 450°C

limited to~ 200°C

thermalbehaviour


Basic features of catalyst designs

HPC-LS

APC-LS

HPC-PC

type

high performance

adapted performance

high performance

large surface

large surface

passive cooling

catalyst support

~ 2 vol.%

< 1 vol.%

~ 2 vol.%

start behaviour

~ 70 %

> 90 %

~ 10 %

efficiency/ element

unlimitedheating uplimited to~ 450°C

limited to~ 200°C

thermalbehaviour

Modular set-up of different elements - examples• medium H2 amount - high acceptance level for PAR temperature

• medium H2 amount - low acceptance level for PAR temperature

• high H2 amount - low acceptance level for PAR temperature


5% H2

in air

system temperature

10%

0%

5%

0% H2

in airHPC

T0

Tmax

hydrogen concentration

Medium inlet H2 concentration high outlet temperature


5% H2

in air

system temperature

10%

0%

5%

0% H2

in airHPC PC

T0

Tmax


Medium inlet H2 inlet concentration low outlet temperature


10% H2

in air

system temperature

10%

0%

5%

0% H2

in airAPC HPC PC

T0

Tmax


High inlet H2 concentration low outlet temperature


Conclusions


• Design Studies

• Conclusions


Conclusions

• PAR can reduce the explosion risk in future hydrogen applications

• Challenge: high efficiency at system temperatures below the ignition limit

• Approach:- adaptation of the catalyst activity- passive cooling elements

• Different types of catalyst elements have been identified and investigated

• Modular set-up in order to adapt the PAR operation behaviour to the boundary conditions of the application


The end

THANK YOU FOR YOUR ATTENTION !

Documents

E.-A. Reinecke , S. Kelm, S. Struth, Ch. Granzow, U. Schwarz*