iet - institute for energy and transport joint research centre, european commission
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International Conference on Hydrogen Safety - 4 September 12-14, 2011 San Francisco, California, USA. Hydrogen Tank Filling Experiments at the JRC-IET GasTeF Facility. IET - Institute for Energy and Transport Joint Research Centre, European Commission Petten - The Netherlands - PowerPoint PPT PresentationTRANSCRIPT
San Francisco on 13 September 2011 – 4th ICHS 1
IET - Institute for Energy and Transport
Joint Research Centre, European Commission
Petten - The Netherlands
http://ie.jrc.ec.europa.eu/
http://www.jrc.ec.europa.eu/
B. Acosta, P. Moretto, N. Frischauf, F. Harskamp and C. Bonato
Hydrogen Tank Filling ExperimentsHydrogen Tank Filling Experimentsat the JRC-IET GasTeF Facilityat the JRC-IET GasTeF Facility
International Conference on Hydrogen Safety - 4
September 12-14, 2011San Francisco, California, USA
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OUTLINE
Hydrogen storage at high pressures
Fast filling issues
GasTeF: Compressed hydrogen Gas Testing Facility
JRC-IET GasTeF temperature evolution experiment
Experimental results
Next steps
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hydrogen storage at high pressures
A type 1 tank, or a standard compressed gas cylinder, is simply a
stainless steel casing holding compressed gas. It has no extra
covering or accessories, except for the coating of paint on the outside that
identifies the contained gas.
A type 2 tank is slightly more durable than a type 1. It has a base cylinder shell made of aluminium or stainless steel, and a partial wrapping around the outside of the cylinder. This wrapping is usually made of a polyester resin containing glass, aramid or carbon.
A type 4 tank is a fully wrapped composite tank with a non- metallic liner. The mechanical loads are therefore only supported by the composite wrapping; the liner itself does not support the loads “non-sharing-load” liner
Type 3 and 4 tanks may also have an additional glass fibre wrappingto protect the tank against external effects
A type 3 tank is a fully wrappedcomposite tank with a metal linermade out of aluminium or stainlesssteel. The composite is wrappedaround the liner. Themechanical loads of the cylinderare supported by both liner and wrapping.
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Tank (re)-fuelling Requirements: Avoid exceeding high temperatures in tank Operating range -40 °C to 85 °C
Reasonable short filling duration Max. 3-5 minutes
… however…
The shorter the filling duration The higher the temperatures inside the tank
Higher gas temperatures Higher filling end pressures to assure a “complete tank filling”
Three major risks to damage tank materials: Over-pressurisation
Temperatures higher than the maximum allowed 85 °C (for example SAE J2579)
Over-filling if fuelling occurs at low ambient temperature
The JRC-IET facility GasTeF is an EU reference laboratory designed to carry out performance verification tests of full-scale high pressure vehicle tanks for hydrogen or
natural gas or of any other high-pressure components
fast filling : safety and convenience aspects
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GasTeF:Compressed Hydrogen Gas Testing Facility
Half-buried bunker with an attached gas storage area.
Designed to endure a sudden energy release equivalent to 50 kg TNT with a safety factor of 10.
Double walls of heavy-concrete, covered by a 3 meter thick sand layer armoured by geotextile every thirty centimetres
The bunker is closed by a gas-tight inner door and after that by a hydraulically operated 40 tons massive concrete door sliding on Teflon plates
The gas detectors form the heart of the safety monitoring system of the bunker
Operated under remote control – inertised during testing
GasTeF: safe testing of tanks and components
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55 kW two-stage pistoncompressor up to 880 bar
H2 / He / CH4
300 bar package
GC and O2 free
H2 detectors2nd Containment
Aluminium Sleeve
1st Containmentpressure vessel The cylinders are placed into a sleeve
which contains an inert gas (He, N2...) and serves as chamber to detect permeation. The H2 level is measured using gas chromatography.
GasTeF layout
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-1 0 1 2 3 4 5 6 7 8 9 10
0
50
100
150
200
250
300
350
400
Tank Pressure Bottom Temperature Top Temperature
Test Duration [h]
Pre
ssu
re [b
ar]
0
2
4
6
8
10
12
14
16
18
20
22
24
26
28
30
Te
mp
era
ture
[ oC]
Static permeation measurement as a function of time on tanks filled up to 70 MPa and up to temperatures to 100 °C.
GasTeF : fast-filling, cycling and permeation tests on any type of hydrogen (and methane) tanks
Fast-filling cycling, in which storage tanks are fast filled and slowly emptied using hydrogen pressurized up to 70 MPa, for at least 1000 times to simulate their lifetime in a road vehicle. During the cycling process the tank is monitored for leaks and permeation rates using gas chromatography.
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Temperature measurement at 3 axial (displaceable) and 5 radial positions
Measurement with He and with H2
Local measurement of H2 temperature
a boom with thermocouples is inserted into the tank
Tank: Raufoss Type 4, 700 bar (29.8 l)
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5
6
1
3
2
4
7
H2 inflow
8
T Top
T Bottom
T BossT Line
The temperature evolution experiment is also used to validate software models for tanks (see next presentation)
Experimental data presented hereafter are preliminary results of the on-going testing campaign to map local temperature evolution inside the tank as a function of filling rate under different starting conditions (Ti, pi) and final pressure pf
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He versus H2
The graph summarises experiments with different filling rates for different pi, pf and Ti
In general H2 features a smaller temperature increase than He (evident only at high fill rates)
Preliminary Results
-1 0 1 2 3 4 5 6 70
20
40
60
80
100
120
Tem
per
atu
re I
ncr
ease
[oC
]
Fill rate [bar/s]
TC-5 He TC-5 H
2
Position T5:
Axial: 500 – 525 mm from gas inlet
Radial: 15 to 35 mm from liner
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The graph summarises experiments with different filling rates and slightly different pi, pf and Ti
Temperature rise influenced by filling rate Variation in temperature rise at a given filling rate is caused by pf, as well as (Ti, pi)
Measured temperatures at the inside and outside of the tank differ significantly
Top_inside
Top_outside
Preliminary Results
Ma
x a
llo
we
d T
0 1 2 3 4 5 60
10
20
30
40
50
60
70
80
90
100
110
120
Fin
al
Te
mp
era
ture
, oC
Fill rate, bar/s
TC-5 T Top
H2
?
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After filling finishes, the temperature sharply decreases due to heat transfer from inside the tank to its outer surface
As temperature decreases, pressure does as well and hence it takes several hours to reach equilibrium values
10/12/2010 12:00 11/12/2010 00:00 11/12/2010 12:00 12/12/2010 00:000
10
20
30
40
50
60
70
80
90
100
Pre
ssu
re [
MP
a]
Tem
per
atu
re [
oC
]
Date
P tank Temperature
Long term static pressure tests
30 hours
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0 5 10 15 20 25 30 350
10
20
30
40
50
60
70
80
Time [minutes]
Pre
ss
ure
[M
Pa
]
-40-30-20-100102030405060708090
Te
mp
era
ture
[ oC]
Example of fill & emptying cycle
Fill
ing Pressure
holding Emptying
non-linear filling induces a complex (non monotonic) gas temperature evolution as soon as filling is finished, gas temperatures inside the tanks follow a stratification
pattern
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a system to cool down the hydrogen when it is supplied to the tank environmental control system to allow simulation of -40°C ambient temperature
Next step: temperature control in GasTeF
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control of gas inlet temperature is not easy!
Example of tank temperature dependence on inlet temperature
TC8, Gas inlet temperature
TC5, gas temperature top of the tank
0 20 40 60 80 100 120 140 160 180 200-60
-40
-20
0
20
40
60
80
100
120
140T
emp
erat
ure
s d
uri
ng
fil
lin
g [
C]
Time [s]
0 20 40 60 80 100 120 140 160 180 200-60
-40
-20
0
20
40
60
80
100
120
140T
emp
erat
ure
s d
uri
ng
fil
lin
g [
C]
Time [s]
With pre-cooling
Without pre-cooling
even without cooling, inlet temperature can increase
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Conclusions
results show that the maximum gas temperature during filling of a type 4 tank can locally exceed the limit established in current regulations and standards.
The results serve to validate the computed fluid dynamic modelling of the fast filling process, also performed at JRC-IET – See next presentation!
First results suggest that the low thermal conductivity of the plastic liner limits the effect of local temperature peaks on the liner itself as well as on the material of the external shell
Is this maximum allowed temperature too limiting?Is this “historical” limit justified for the materials used?Is it important to consider the duration of the temperature overshoot?
Next experimental step is to place the thermocouples touching or as close as possible to the tank internal surface to obtain accurate measurements of the liner temperature during filling and emptying
measurements are in good agreement with those found in literature
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Thank you for your attentionThank you for your attention
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In normal operation the facility runs fully automatically and the tests are operator controlled from a control room situated in an adjacent building
control by PLCs and specific software tools