Dahoe AE — Hydrogen Storage — AConcise Overview

intermetallic compound with iron, but in the presence of hydrogen it is possible to synthesize the rather stable ternary hydride Mg2FeH6 with 5.5 mass% hydrogen26.

Figure 6 Stored hydrogen per mass and
per volume. Comparison of metal hydrides, carbon nanotubes, petrol and other hydrocarbons.

ht review articles

160

Mg2NiH2
BaReH9

140

olume of 4 kg of
compacted in different
size relative to the size of ge of car courtesy of ss information, 33rd or Show, 1999.)

600 K, 4 bar

CnanoH0.95
LiBH4

LaNi5H6

MgH2

300 K, 2 bar

620 K, 5 bar

dec. 553K

NaBH4
dec. 680 K

C8H18liq.

H2 chemisorbed
on carbon

KBH4

FeTiH1.7

100

0.7 g cm-3

1 g cm-3

<373 K, 1 bar

120
ρv (H2) (kg H2 m-3)

2 g cm-3

5 g cm-3

Density:

dec. 580 K

300 K, 1.5 bar

LiAlH 4
dec. 400 K

CH4liq.

b.p. 112 K

C4H10liq.
b.p. 272 K

H2liq.

NaAlH4

80

20.3 K

dec. >520 K

60

H2 physisorbed
on carbon

40

20

Metal Hydride Canister
0

LaNi5H6

H2 (liquid)

H (200 bar)
Hydrogen
Supply Solution
Required volume for 4 kg hydrogen storage. From [1].
2

5

10

15
ρm (H2) (mass%)

20

35.0

NATURE | VOL 414 | 15 NOVEMBER 2001 | www.nature.com

© 2001 Macmillan Magazines Ltd

Pressure [bar]

per container volume. The density of liquidLow-pressure hydrogen is 70.8 kg metal m–3 30.0hydride canisters enable High charge limit (70.6 kg m–3 for solid hydrogen). But the condensation temperature safe and easy of hydrogen at 1 bar is –252 7C and the vaporization enthalpy at theintermediate storage of larger boiling point amounts to 452 kJ kg–1. As the critical temperature of 25.0 quantities hydrogen in a very compact form.
hydrogen is –241 7C (above this temperature hydrogen isofgaseous), Hydrogen gas liquid hydrogen containers are open systems to prevent strong pressure overpressure. Therefore, heat transfer through the container leads 20.0 93 93 a smaller surdirectly the loss hydrogen.
Larger containers ρ = to 0.09 kgofm = 0.00009 g cmhave Low charge limit the isideal solution especially for face to volume ratio than so the 93 lossare of hydrogen 93small containers,They 15.0 At 350 bar and 25 C:
ρ = 26.1 kg m = 0.0261 g cm smaller. The continuously evaporated hydrogen may be catalytically onal hydrogen storage ◦ to burnt with air in the93 93 of the with systems limited system container or installation space.
high-pressure tanks madeAt of fairly steeland are tested 700cheap bar 25 up C: ρ = 42 kg m overpressure = 0.042safety g cm nd regularly filled up to 200 bar in most countries. To store collected again in a metal hydride. (Solid hydrogen is a molecular 10.0 Liquid Hydrogen ydrogen still requires an internal volume of 225 litres (about insulating solid; under high pressure it transforms into metallic, 287.5 300 312.5 325 4 ◦ 93T of 200–300 7C.) evenkg superconducting hydrogen s) or 5 tanks of 45 litres each.
Novel high-pressure tanks made with At 1 bar and -253 C: possibly ρ = 71 m93 = 0.071 g cm c Temperature [K] -fibre-reinforced composite materials are being developed;
Cryotechniques for cooling and superinsulated low temperature Solid-gas equilibrium curves:
Metal Hydride Canister tested up to 600 bar and filled up to 450 bar for regular use. storage units were developed and proven in space technology. Liquid need a special inert inner coating to prevent the high- hydrogen is a fuel in the launching process of the Space Shuttle and in MgH2 (s) ←−→ Mg (s) + H2 (g).
hydrogen reacting with the polymer. Consequently, another Ariane. A Lockheed military-type aircraft and a Tupolev supersonic is to use hydrogen-inert aluminium tanks and to strengthen aircraft have been of flown with engines fuelledKnowledge by liquid hydrogen.
[Dr A.E. Dahoe:
Principles Hydrogen Safety, Center for Explosion and Hydrogen Safety, Dutch Armed Forces] h external carbon-fibre coatings. Spherical containers slight- BMW have built an automated liquid-hydrogen filling station, and than 60 cm in diameter would be able to carry our 4 kg, but developed and tested several cars running with hydrogen in newly cal fabrication a cylindrical shape is preferred.
designed vessels to reduce losses by evaporation to below 1.5 mass% high-pressure containers, when full, would contain about per day(BMW, personal communication).
ogen by mass, but with significant disadvantages: the fuel Hydrocarbons with a molecular mass of at least 60 g mol–1 are2 available at a pressure dropping from 450 bar to zero over- liquid at room temperature with a density close to 1,000 kg m–3. The so additional pressure control would be essential. number of hydrogen atoms per carbon atom can vary in hydrocarssure vessels present a considerable risk — the compression bons owing to their ability to change from s-bonds to p-bonds.
he most dangerous and complicated part. In Japan such Hydrocarbons can be burnt completely by oxidation of carbon into

d for the combustion engine version or 4 kg hydrogen for c car with a fuel cell.
ogen is a molecular gas. At room temperature and eric pressure, 4 kg of hydrogen occupies a volume of 45 m3.
esponds to a balloon of 5 m diameter — hardly a practical for a vehicle (Table 1). In the following we will focus on Gaseous ion of compacting hydrogen, looking atHydrogen the materials, technd safety aspects (Fig. 1).
At 1 bar and 25 ◦ C:
◦

25

357

Education & Research

0

Mg2NiH4

een
ressure
drogen
etal
ficient way

ravimetric
y show a
an still be
oretical
avimetric ed in this

mt für Energie,
deral Office of
SIA), and the

Volumetric and gravimetric hydrogen density of some selected hydrides. [2].

Fig. 7 Volumetric and gravimetric hydrogen density of some selected hydrides. Mg2FeH6 shows the highest known volumetric hydrogen density of 150 kg·m-3, which is more than double that of liquid hydrogen. BaReH9 has the largest H/M ratio of 4.5, i.e. 4.5 hydrogen atoms per metal atom. LiBH4 exhibits the highest gravimetric hydrogen density of 3 18 mass%. Pressurized gas storage is shown for steel (tensile strength σv = 460 MPa, density 6500 kg·m-3) and a hypothetical composite material (σv = 1500 MPa, density

AMMONIA AS A HYDROGEN CARRIER?
Hydrogenation:

N2 (g) + 3 H2 (g) −−−−−→ 2 NH3 (g) −−−−−−→ 2 NH3 (l)

Dehydrogenation:

2 NH3 (g) −−−−−−→ N2 (g) + 3 H2 (g)

2 ∆f HNH3

−2 ∆v HNH3

−2 ∆f HNH3

∆f HNH3 = -46.1 kJ mol−1 = -2.71 MJ kg−1
∆v HNH3 = 23.5 kJ mol−1 = 1.38 MJ kg−1 ∆c HNH3 = -382.8 kJ mol−1 = -22.477 MJ kg−1

1 kg H2 requires 5.7 kg NH3

WATER AS A HYDROGEN CARRIER?
Hydrogenation:

O2 (g) + 2 H2 (g) −−−−−→ 2 H2 O(l)

Dehydrogenation:

2 H2 O(l) −−−−−−→ O2 (g) + 2 H2 (g)

2 ∆f HH2 O

−2 ∆f HH2 O

∆f HH2 O = -286 kJ mol−1 = -15.9 MJ kg−1
∆v HH2 O = 40.63 kJ mol−1 = 2.26 MJ kg−1

1 kg H2 requires 9 kg H2 O

4

Chemical
formula

Hydrogen
(wt%)

CH4
NH3BH3
LiBH4
(CH3)4NBH4
NH3
Al(BH4)3
Mg(BH4)2 LiH CH3OH H2O LiAlH4 NaBH4 AlH3 MgH2 NaAlH4

25
19.6
18.3
18
17.7
16.8
14.8
12.6
12.5
11.2
10.6 10.6 10.0 7.6 7.4

HYDROGEN FROM METHANE
CH4 + H2 O −
↽−
−⇀
− CO + 3 H2 − − ⇀ CO + H2 O ↽−− CO2 + H2 CH4&+ Fuels 2 H2 O − Energy ↽− −⇀ − CO2 + 4 H2

(steam reforming)
(water-gas shift reaction)
(overall reaction) pubs.acs.org/EF

nevertheless the need to re
specific energy demand for these conditions.
1.2. Chemical-Looping with SMR. To avoid the ene capture, Rydén and Lyngfe configuration with chemic gaseous fuels and reformer t The process configuration in

From:
[3].
Figure
1. Schematic
of classical steam methane reforming (SMR) with a postcombustion CO2 capture system.
5

SMR is carried out in tubular reactors filled with catalyst where the inside gas temperature may vary from 600 to 900 °C,

Energies
Energies 2020,
2020, 13,
13, x
x FOR
FOR PEER PEER REVIEW REVIEW Energies 2020, 13, x FOR PEER REVIEW Energies 2020, 13, xx FOR PEER REVIEW Energies 2020, 13, FOR PEER REVIEW Energies 2020, 13, 6040

16
16 of
of 23
23
16 of 23
16
of
23
16
of
23
8 of 23

Table
1.
of
Table
1. Typical
Typical examples
examples of potential potential LOHCs LOHCs and and their their physicochemical physicochemical properties.
properties.
Liquid-Organic HydrogenTable Carriers (LOHC) Table 1. Typical examples of potential LOHCs and their physicochemical properties.
1. Typical examples of potential LOHCs and their physicochemical properties.

Table
properties.
Table 1. Typical
Typical examples of potential LOHCs and their physicochemicalMelting Boiling Melting Point Point Boiling Point Point Flash Melting Point Boiling Point Flash Point Point (° (°C) C) (° C) (° C) Melting Point Boiling Point H 2 Capacity Enthalpy (kJ/mol Flash Point (°C) (° C) (° C) H 2 Capacity Enthalpy (kJ/mol ◦ ◦ Melting Point Boiling Point H Flash Point C) Melting C) Flash Point (◦ C)(° LOHC (°C) Boiling Point ((° C) H22 Capacity Enthalpy (kJ/molPoint ( C)(° Enthalpy LOHC System System Flash Point (° C) H H Capacity Enthalpy H H H H LOHC LOHC System System (wt%) H22))(kJ/mol C) H (°C) C) H H22-- (°C) H22-H22-- (° H22-H22-H22-Capacity H22 (wt%) Capacity (kJ/mol LOHC (kJ/mol Enthalpy H2 ) H (wt%) H2H2 2-Rich HH2-2 -Lean H2-H2 -Rich H2- H2 -Lean H2LOHC System System H222))-Rich H2Rich -Lean H (wt%) H Lean Rich Lean Rich Lean H 2 H 2 H 2 H 2 H 2 H (wt%)(wt%) Rich Lean Rich Lean Rich Lean H2) H2H2H2H2H2H22-Rich Lean Rich Lean Rich Lean Rich Lean Rich Lean Rich Lean Methylcyclohexane → toluene toluene Methylcyclohexane→ Rich Lean Rich Lean Rich Lean Methylcyclohexane→ toluene Methylcyclohexane→ toluene Methylcyclohexane→ toluene Methylcyclohexane→ toluene 68.3 −126 −95 101 6.2 6.2 68.3 −126 −95 101 6 66 6.2 68.3 −126 −95 101111 111 111 −3 −3 −3 6.2 68.3 −126 −95 101 111 −3 6 6.2 68.3 −126 −95 101 111 −3 66 6.2 68.3 −126 −95 101 111 −3 Decalin→ Decalin→ Naphthalene Decalin → Naphthalene Decalin→ Naphthalene Decalin→ Decalin→ Naphthalene Naphthalene

7.3

7.3
7.3
7.3
7.3
7.3

63.9

63.9
63.9−37
63.9
63.9
63.9

−37
−37
79
−37
−37
−37

79
79
189
79
79
79

189
189218
189
189
189

218
218
218
218
218

57
57
57
57
57

80
80 80
80
80
80

57

Perhydro-dibenzyltoluene→
Perhydro-dibenzyltoluene→ dibenzyl dibenzyl toluene toluene Perhydro-dibenzyltoluene → dibenzyl dibenzyl toluene toluene Perhydro-dibenzyltoluene→ Perhydro-dibenzyltoluene→ Perhydro-dibenzyltoluene→ dibenzyl dibenzyl toluene toluene 6.2

6.2
6.2
6.2
6.2
6.2

65.4

65.4
65.4
65.4NA
65.4
65.4

NA
NA
NA
−34
NA
NA

−34
−34
−34
NA
−34
−34

NA
NA
NA398
NA
NA

398
NA
398
NA
398 NA NA
398
NA
398
NA

190
190
190
190190
190

6.2

6.2
6.2
6.2
6.2
6.2

63.5

63.5
63.5
63.5
63.5
63.5NA

NA
NA
NA
NA
−30
NA

−30
−30
−30
−30
270
−30

270
270
270
270
270 280

280
NA
280
NA
280
NA
280
280 NA NA
NA

NA
NA
NA
NA
NA
NA

5.8

5.8
5.8
5.8
5.8
5.8

50.6

50.6
50.6
50.6
50.6
50.6−85

−85
−85
−85
−85
−85
70

70
70
70
70
70
NA

NA
NA
NA
NA
NA166

166
NA
166
NA
166
NA
166
NA
166 NA NA

186
186
186
186
186186

Perhydro-benzyl
Perhydro-benzyl toluene→
toluene→ benzyl benzyl toluene toluene Perhydro-benzyl toluene→ benzyl toluene Perhydro-benzyl → benzyl benzyl toluene toluene Perhydro-benzyl toluene→ Perhydro-benzyl toluene toluene→ benzyl toluene

Dodecahydro-N-ethyl
Dodecahydro-N-ethyl carbazole carbazole →N-ethyl →N-ethyl carbazole carbazole Dodecahydro-N-ethyl carbazole →N-ethyl carbazole Dodecahydro-N-ethyl carbazole →N-ethyl carbazole Dodecahydro-N-ethyl carbazole carbazole → →N-ethyl Dodecahydro-N-ethyl N-ethyl carbazole

From: [4].

6

Energies 2020, 13, 6040

9 of 23

Liquid-Organic Hydrogen Carriers (LOHC)
Energies 2020, 13, 13, x FOR PEER PEER REVIEW Energies LOHC System Energies 2020, 2020, 13, xx FOR FOR PEER REVIEW REVIEW Energies 2020, 13, x FOR PEER REVIEW Energies 2020, 13, x FOR PEER REVIEW

Table 1. Cont.
H2
Capacity
(wt%)

Enthalpy
(kJ/mol H2 )

5.8

5.8
5.8
5.8
5.8
5.8

5.8

5.8
5.8
5.8
5.8
5.8

Melting Point (◦ C)

Boiling Point (◦ C)

H2 -Rich

H2 -Lean

H2 -Rich

H2 -Lean

51.9

51.9NA
51.9
51.9
51.9
51.9

NA
95
NA
NA
NA
NA

95
180
95
95
95
95

180238
180
180
180
180

NA

NA
NA
NANA
NA
NA

NA
NA
60
NA
NA
NA

60
60
178
60
60
60

178
178
178 272
178
178

NA

NA
NA
NA
<−15
NA
NA

<−15
<−15
<−15
55
<−15
<−15

NA

NA
NA
NA
NANA
NA

67.3
67.3
67.3
67.3
67.3
−19.3

Flash Point (◦ C) 17 of 23
17
17 of
of 23
23

H2 -Rich

17 of 23
H2 -Lean
17 of 23

238
238
238
238
238

60

60
60
60
60
60

110
110110
110
110
110

272
272
272
272
272

58

58
58
58
58
58

141
141141
141
141
141

55
55
55
≥260.5
55
55

≥260.5
260.5
≥230
≥260.5
260.5
≥230
≥260.5
≥230 260.5 260.5 ≥260.5 260.5 ≥230≥230 ≥260.5 260.5 ≥230

≥230
≥230
≥230
≥230
≥230
≥230

NA
NA
NA
NA
174–177
NA

174–
174–
174–
174–
177
177
174–
NA
177
177
177

NA
357.2
NA
NA
357.2
NA
NA
357.2
NA
NA357.2 357.2 NA NA NA 357.2 NA

160.3
160.3
160.3
160.3
160.3
160.3

−19.3
−19.3
−19.3
−19.3
−19.3
−50.1

−50.1
−50.1
−50.1
−50.1
−50.1
293

293
293
293
293
293 291

NA
NA
NA
NA
NANA

1-methylperhydroindole
indole→1-methyl
1-methylperhydro → 1-methyl indole indole 1-methylperhydro 1-methylperhydro indole→1-methyl indole→1-methyl indole indole 1-methylperhydro indole→1-methyl indole 1-methylperhydro indole→1-methyl indole

2-methylperhydro indole→2-methyl
indole→2-methyl indole indole 2-methylperhydro 2-methylperhydro → 2-methyl indole indole 2-methylperhydroindole indole→2-methyl 2-methylperhydro indole→2-methyl indole 2-methylperhydro indole→2-methyl indole

1,2-perhydrodimethyl indole→1,2-dimethyl
indole→1,2-dimethyl indole indole 1,2-perhydrodimethyl 1,2-perhydrodimethylindole indole→1,2-dimethyl 1,2-perhydrodimethyl → 1,2-dimethyl indole indole 1,2-perhydrodimethyl indole→1,2-dimethyl indole 1,2-perhydrodimethyl indole→1,2-dimethyl indole 5.23 5.23 5.23 5.23 5.23 5.23 Perhydro-phenazine → → phenazine Perhydro-phenazine Perhydro-phenazine→ → phenazine phenazine Perhydro-phenazine Perhydro-phenazine →phenazine phenazine Perhydro-phenazine → phenazine 7.2

7.2
7.2
7.2
7.2
7.2

Perhydro-2-(n-methylbenzyl pyridine) →
→ 2-(n-methylbenzyl pyridine) pyridine) Perhydro-2-(n-methylbenzyl Perhydro-2-(n-methylbenzyl pyridine) pyridine) → 2-(n-methylbenzyl 2-(n-methylbenzyl pyridine) Perhydro-2-(n-methylbenzyl pyridine) → 2-(n-methylbenzyl pyridine) Perhydro-2-(n-methylbenzyl pyridine) → 2-(n-methylbenzyl pyridine) Perhydro-2-(n-methylbenzyl pyridine) → 2-(n-methylbenzyl pyridine) 6.15 6.15 6.15 6.15 6.15 6.15

67.3

From: [4].

7

291
NA
291
NA
291
NA
291
NA
291 NA NA

AGGREGATION STATES, PHASE DIAGRAM AND EQUATIONS OF STATE hydrogen

108

liquid
metal

H metal
6

Pressure [bar]

10

4

10

H2 gas

102
critical point
0

10

H2
solid

H2 liquid
triple point

H gas

10−2
100

101

102
103
104
Temperature [K]

105

106

Phase diagram [5].

EQUATIONS OF STATE
Idea Gas Law: P (V /n) = RT Nobel-Abel: P [(V /n) − b] = RT   a Van der Waals:
P+ [(V /n) − b] = RT (V /n)2 27R2 T 2 c and b = RT a = 64P c 8Pc c Beattie-Bridgeman:
  (V /n) 3 T 3 A  P+ = RT 2 3 (V /n)  (V /n)T − c [(V /n) + B]   a b A = A0 1 − and B = B0 1 − (V /n) (V /n) Constants a, b, c, A0 , and B0 assume different values for each substance.
Benedict-Webb-Rubin:
i h C 1 − bRT − aα 0 P − B0 RT − A0 − 2 5 T (V /n) (V /n)2 (V /n) γ γ c − = RT 2 2 1+ 2 exp − (V /n) T (V /n) (V /n)2 Substance specific constants a, b, c, A0 , B0 , C0 , α, and γ.

H2 and CH4 density as a function of pressure [6].
8

namic changes associated with a temperature drop. The latter are split in processes where the media provides mechanical work in expansion turbines “expanders” or in piston machines and in isenthalpic throttling in Joule 2 Thomson valves.

Density of hydrogen as a function of temperature at different pressure levels. [7].

FIGURE 2.14

Density of normal hydrogen dependent on temperature at different pressure levels (Kuhn, 2015).

9

architectures
and
arethe
currently
organized
into five main types, numerically classified from R&D efforts are now pursuing cost-efficient lightweight materials, designs Imobility, to IV [93,94].
With growing popularity of advanced hydrogen solutions employed in and 3.1.
Industrial Hydrogen Tank-Type Classification 3.1.
Industrial Hydrogen Tank-Type Classification production to take hydrogen tanks even further.
mobility, R&Dtechnologies efforts are now pursuing cost-efficient designs the tank, and have to belightweight created by materials, the designer whenand planning viable manufacturing.
Imobility, to IV [93,94].
With theare growing popularity of advanced hydrogen solutions employed in production technologies to take hydrogen tanks even further.
R&D efforts now pursuing cost-efficient lightweight materials, designs and 3.1.
Industrial Hydrogen Tank-Type Classification Pressure vessels used in the marketplace for general applications assume different Figure 3 and Tableto5take introduce a classification for the sub-types of hydrogen tanks production technologies hydrogen tanks even further.
3.1.
Industrial Hydrogen Tank-Type Classification Pressure vessels used in sub-types the marketplace forand general assume different mobility, R&D aretonow pursuing lightweight materials, production technologies hydrogen tanks even further.
Figure 3 efforts and Table 5take introduce acost-efficient classification for the ofdesigns hydrogen tanksapplications architectures and are currently organized into five main types, numerically classified from aimed to 3comprehend recent advances and future design trends, with additional Pressure vessels used in the marketplace for general applications assume different 3.1.
Industrial Hydrogen Tank-Type Classification Figure and Table 5 introduce a classification for the sub-types of hydrogen tanks architectures and are currently organized into five main types, numerically classified production technologies to take hydrogen tanks even further.
Pressure vessels used insub-types the marketplace for general applications assume different from Figure 3 and Table 5recent introduce classification for the of hydrogen tanks aimed to comprehend advances and future design trends, with additional distincI to aIV [93,94].
With the growing popularity of advanced hydrogen solutions employed architectures and are currently organized into five main types, numerically classified fromin in distinctions establishedrecent between the reinforcement type, matrix type and winding aimed to comprehend advances and future design trends, with additional Pressure vessels used in the marketplace for general applications assume different Ireinforcement to IV [93,94].
the growing popularity ofmethod.
advanced solutions employed Figure 3 and Table 5recent introduce a classification the sub-types ofwinding hydrogen tanks architectures andWith are for currently organized into five main types,hydrogen numerically classified from aimed to comprehend advances and future design trends, with additional tions established between the type, matrix type and mobility, R&D efforts are now pursuing cost-efficient lightweight materials, designs and method. established between I advances to IV With the growing popularity offive advanced hydrogen solutions employed in distinctions the[93,94].
reinforcement type, matrix type and winding architectures and arethe currently organized into main types, numerically classified from aimed to comprehend and future design trends, with additional R&D efforts are now pursuing cost-efficient lightweight materials, designs Imobility, to IV With growing popularity of advanced hydrogen solutions employed in and distinctions established recent between the[93,94].
reinforcement type, matrix type and winding production technologies to take hydrogen tanks even further.
mobility, R&DWith efforts are nowmatrix pursuing cost-efficient lightweight materials, designs and method.
Imobility, to IV theare growing popularity oftanks advanced hydrogen solutions employed in distinctions established between the[93,94].
reinforcement type, type and winding production technologies to take hydrogen even further. materials, R&D efforts now pursuing cost-efficient lightweight designs and method.
Figure 3 and Tableto5take introduce a classification for the sub-types of hydrogen tanks production technologies hydrogen tanks even further.
mobility, R&D efforts are now pursuing cost-efficient lightweight materials, designs and method.
production technologies to take hydrogen tanks even further.
Figure 3 and Table 5 introduce a classification for the sub-types of hydrogen tanks aimed to 3comprehend recent advances and future trends, with additional Figure and Table 5 introduce a classification for thedesign sub-types of hydrogen tanks production technologies take hydrogen tanks evenfor further.
Figure 3 and Table 5to introduce a classification the sub-types of hydrogen tanks aimed to comprehend recent advances and future design with additional distincdistinctions established between the reinforcement type, trends, matrix type and winding aimed to comprehend recent advances and future design trends, with additional Figure 3 and Table 5recent introduce a classification for the sub-types ofwinding hydrogen tanks aimed to comprehend advances and type, future design trends, with additional tions established between the reinforcement matrix type and method.
method. established between the reinforcement type, matrix type and winding distinctions aimed to comprehend advances and future type, design trends, with distinctions established recent between the reinforcement matrix type andadditional winding method.
distinctions established between the reinforcement type, matrix type and winding method.
method.

GASEOUS HYDROGEN – VEHICLE STORAGE TANKS

Figure3.3.Classification
Classification for
tanks used in in industrial applications.
Figure for the thesub-types sub-typesofofhydrogen hydrogen tanks used industrial applications.

[95]
[95]
[95]

[95]
[95]

Figure 3. Classification for the sub-types of hydrogen tanks used in industrial applications.
Figure for the sub-types of hydrogen tanks tanks;
used inrecent industrial applications.
Table3.5.Classification Industrial winding configurations for hydrogen advances and future design Figure 3.
Classification for the sub-types of hydrogen tanks used in industrial applications.
Table 5.
Industrial winding configurations for hydrogen tanks;
recent advances and future design trends.
Table 5. Industrial winding configurations for hydrogen tanks; recent advances and future design Table 5. Industrial winding configurations for hydrogen tanks; recent advances and future design trends.
trends.
Table configurations for hydrogen recent advancesRecyclabi and future design trends.5. Industrial winding Resin tanks;
Fiber Light Sub-Type Wrap Winding Low Costof hydrogen tanks used in industrial applications.
Liner Figure3.3.Classification Classification for trends.
Figure for the thesub-types sub-types of hydrogen tanks used in industrial applications.

Light
Wrap
Winding
Sub-Type
Classification
Extent Method Resin Type Fiber TypeLow Cost Recyclabi lity Weight Resin Fiber Light Sub-Type Wrap Winding Recyclability Liner Sub-Type Wrap Method Winding Resin Fiber Light Low CostofRecyclabi Liner Extent Figure 3. Classification for the sub-types hydrogen tanks used in industrial applications.
Weight Type Type Classification 1 Liner Low Cost Type II—FSW Metal Cylinder Wet TS CF +++ ++++ +

Classification
Extent
Method
Type
Type
lity
Weight Figure for the sub-types ofRecyclabi hydrogen tanks used inrecent industrial applications.
Resin Fiber Light Sub-Type Wrap Winding Table3.5.Classification Industrial configurations for hydrogen tanks;
advances and future design Classification Extent Type winding Type lity Weight Method Low+++ Costof hydrogen Liner 1 Figure 3.
Classification for the sub-types tanks used in industrial applications.
Table 5.
Industrial winding configurations for hydrogen tanks;
recent advances and future design Type II—FSW Metal Cylinder Wet TS CF ++++ + 1 Type II—MSW Metal Cylinder Wet TS SW +++++ +++++ + trends.
Classification Extent Method Type Type lity Weight 1 Cylinder Wet TS CF +++ ++++ + Metal Type II—FSW Table 5.
Industrial winding configurations for hydrogen tanks;
recent advances and future design Type II—FSW Metal Cylinder Wet 5. Industrial TS winding CF configurations +++ ++++ + Table for hydrogen tanks;
recent advances and future design trends.
1 1 Metal Type II—MSW SW +++++ +++++ trends.
Type II—FSW Cylinder Wet TS CFCF +++ ++++ ++ ++ +recent advances and future design Type III—FSW Metal Cylinder Full Wet Wet +++ for +++ Type II—MSW Metal TS SW +++++ +++++ Type II—MSW Metal Cylinder Wet TSTS winding SW +++++ +++++ Table 5. Industrial configurations hydrogen trends.
Resin tanks;
Fiber Recyclabi Light Sub-Type Wrap Winding 1 [95] Liner Type III—FSW Full CF +++ +++ ++ Type II—MSW Metal Wet TS SW +++++ +Fiber Type III—MSW Metal Cylinder Full Wet SW Winding ++++ ++++ +Type Low Cost trends.
1 Light Resin Sub-Type Classification Extent Method+++++ Type Fiber lity Weight Resin Recyclabi Light Sub-Type Wrap Winding Type III—FSW Metal Full Wet TSTS Wrap CF +++ +++ ++ 1 Metal Full Wet TS CF +++ +++ ++ Low Recyclability Liner [95] Type III—FSW Resin Fiber Light Sub-Type Wrap Winding LowCost Cost Recyclabi Liner 1 1 [95] Weight Extent Method Type Type Classification Type III—MSW SW ++++ ++++ + 1 Type III—FSW Metal Full Wet TS CF +++ +++ ++ Type IV—FSW Plastic Full Wet TS CF + ++ +++++ Low Cost [95] Liner Type II—FSW Metal Cylinder Wet TS CF +++ Recyclabi ++++ Weight + Classification Extent Method Type Type lity Type III—MSW Metal TS SW ++++ +Fiber Resin Light Sub-Type Wrap Winding TypeREVIEW III—MSW Metal FullFull WetWet TS SW ++++ ++++ Classification Extent Method ++++ Type Type lity Weight Energies 2022, 15, x FOR Type PEER 10 of 34+ Low Cost 1 [95] Liner Type IV—FST Plastic Full Tape TS Cylinder +Wet ++++ +++++ 1 IV—FSW Plastic CFCF +Wet ++++ +++++ III—MSW Metal Full Wet TS SW ++++ + Type II—FSW Metal TS CF +++ ++++ + 1 1 Type II—MSW Metal Cylinder TS SW +++++ +++++ + Classification Extent Method Type Type lity Type Plastic FullFull TS Cylinder CF ++ +++++ Wet TS CF ++++ Weight + Metal Type II—FSW Type Metal Cylinder TS CF +++ ++++ + Plastic WetWet1 TS CF ++Wet ++ +++++ +++ Type IV—FSW IV—FSW 1 Type IV—FPT Plastic FullII—FSW Tape +++++ Type IV—FST Plastic Full Tape TSTP CFCF ++ +++++ +++++ +++++ 1 1 1 Metal Type Plastic Wet TS CF + ++ Type II—MSW SW +++++ +++++ TypeIV—FSW IV—FST Plastic Tape TS CF + ++ +++++ Type II—FSW Cylinder Wet TS CF +++ ++++ + Type III—FSW Metal Full Wet TS CF +++ +++ ++ Type IV—FST Plastic FullFull Full Tape TS CF + ++ +++++ Type II—MSW II—MSW Metal Cylinder WetWet TS SW +++++ +++++ + Type Metal Cylinder TS SW +++++ +++++ + Type IV—FPT Plastic Plastic Full Tape TP CF + +++ +++++ Type IV—FPT IV—FPT Tape TP CF ++ +++++ Type IV—FST Plastic Tape TS CF +++++ +++++ Type Plastic FullFull Full Tape11 Metal TP CF +Wet +++ +++++ Type III—FSW Full CF +++ +++ ++ Type II—MSW Cylinder TS SW +++++ +++++ + Type III—MSW Metal Full Wet TS SW ++++ ++++ + Type IV—FPW Plastic WetWet TP CF ++Wet +++ +++++ +++ III—FSW Metal Full TS CF +++ +++ ++ ++ Type IV—FPW Plastic FullType Full TP CF +++ +++++ 1 Metal Full Wet TS CF +++ Type III—FSW Type IV—FPT Plastic Full Tape TP CF + +++ +++++ 1 1 Metal Type III—MSW SW ++++ ++++ + Type IV—MSW Plastic Full Wet TS SW ++++ ++++ +++ Type III—FSW Full Wet TS CF +++ +++ ++ Type IV—FSW Plastic Full Wet TS CF + ++ +++++ Type IV—MSW Plastic Full Wet Metal TS SW ++++ ++++ +++ Type III—MSW Metal Wet TS SW ++++ ++++ + TypeREVIEW III—MSW FullFull Wet TS SW ++++ ++++ + Energies 2022, 15, x FOR Type PEER 10 1 Type IV—FST Plastic Full Tape TS CF + ++ +++++ IV—FSW Plastic CF + ++ +++++ III—MSW Metal Full Wet TS SW ++++ ++++ + of 34 1 1 Type IV—FSW Plastic Full Wet TS CF + ++ +++++ LinerTS CF+++++ + ++ +++++ Type IV—FSW FullFull Tape TS/TP ++ ++ Type Liner-less Tape1 Plastic TS/TP CF ++ Type VV2 2 Type IV—FPT Plastic FullCF Full Wet Tape ++ +++++ Type IV—FST Plastic Full Tape TSTP +++++ CFCF ++ +++++ +++++ +++++ less Type Plastic Wet TS CF ++ TypeIV—FSW IV—FST Plastic TapeTape TS CF ++ +++++ Type IV—FST Plastic FullFull Full TS CF + ++++ +++++ Type IV—FPT Plastic Plastic FullFull Full Tape TP CF + +++ +++++ Type IV—FPT IV—FPT CF ++ +++++ 1Tape Type IV—FST Tape TS CF +++++ +++++ TS: thermoset; TP: thermoplastic;
CF: carbonPlastic fiber; SW: steel wire.
frequentTP configuration.
Type Plastic Full Tape TP CF 2 + +++ +++++ 1 MostMost 2 Early TS: thermoset; TP: thermoplastic;
CF:
carbon fiber;
SW:
steel wire.
frequent configuration.
stage of Type IV—FPW Plastic Full Wet TP CF + +++ +++++ Type IV—FPW Plastic Full Wet TP CF + +++ +++++ Type IV—FPT Full Tape TP CF + +++ +++++ Early stage of development.
“+”, “++”, “+++”, Plastic “++++” denotes and “+++++” denotes ascore, comparative score,tofrom development. “+”, “++”, “+++”, “++++” and “+++++” a comparative from very low SW very high.
Type IV—MSW Plastic WetWet TSTS ++++ ++++ Plastic FullFull SW ++++ ++++ +++ +++ very low to very high. Type IV—MSW

From Ref. [8].

Liner-

22
FullFull
Tape
TS/TP
CF
+++++
Type
Tape tank TS/TP CFand are++ ++ ++++ +++++ Type VV TypeVVtanks tanksare arebound bound bethe theLiner-less ultimate step thehydrogen hydrogen tank evolution Type totobe ultimate step ininthe evolution and less currently the focus of intense research [96,97]. [96,97].
This all-composite liner-lessliner-less configuration are currently the focus of intense research ThisCF:all-composite 1 TS: thermoset;
TP: thermoplastic;
carbon fiber; SW:
steel wire.
frequent configuration. 2 1 MostMost TS:
thermoset;
TP:
thermoplastic;
CF:
carbon fiber;
SW:
steel wire.
frequent configuration. 2 Early stage of promises the lightest solution, with a more efficient use of volume, while also reducing configuration promises the lightest solution, with a more efficient use of volume, while Early stage of development.
“+”, “++”, “+++”, “++++” and “+++++” denotes a comparative score, from development. “+”, “+++”, “++++” and “+++++” denotes a comparative score, from very low to very high.
10 “++”, also reducing manufacturing costs, operational risks and maintenance costs due to its very low to very high.
inherently simpler construction [98]. Avoiding permeation, however, constitutes a major Typevery tanks arebound bound bethe theultimate ultimatestored stepinin thehydrogen hydrogen tank evolution and are challenge once hydrogen is a gas with small-sized molecules, usually at Type VVtanks are totobe step the tank evolution and

–
–
–
–
–

3

3

Molecular weight
30.86 g/mol
Hydrogen content
19.6 % wt Density (pelletized) 0.74 g/cm3 NH BH3 (AMMONIA BORANE) Melting 3point 112 - 114 °C Hydrogen evolved ≥ 70 °C

BenignDEHYDROGENATION
by-products
Thermolytic:
Low bulk manufacturing costs 90 ◦ C

H3 BNH3 (s) −−−→ H2 BNH2 (s) + H2 (g)

– New ξPurdue
synthesis
process
H2 BNH2 (s) −
−→ [H2 BNH2 ]ξ (s) 155 ◦ C

[H2 BNH2 ]ξ (s) −−−→ [HBNH]ξ (s) + ξ H2 (g)

Future Soldier Power

> 500 ◦ C

[HBNH]ξ (s) −−−−−→ ξ BN (s) + ξ H2 (g)
Catalytic:
catalyst

3 H3 BNH3 (non9aq) −−−−−−−−−→
tetrahydrofuran

B3 N3 H6 (non9aq) + 6 H2 (g)
NH3 BH3 = ammonia borane.
H2 BNH2 = aminoborane.
[H2 BNH2 ]ξ = polyaminoborane.
HBNH = iminoborane (lower-left).
[HBNH]ξ = polyiminoborane.
B3 N3 H6 = borazine (lower-right).
BN = boron nitride.

06-18-11

06-18-18

From [9].
11

MILITARY GRADE LITHIUM ION BATTERIES

CHARGING:

Fe2+ −−→ Fe3+

DISCHARGING:

Fe3+ −−→ Fe2+

Electrolyte: LiPF6 and H−[CH3 F]n −H
Solid Electrolyte Interface:
(cathode) Li(1−ξ) FePO4 ←−→ Liξ C6 (anode) Charging progress variable, ξ:
Discharge progress variable, η = 1 − ξ:
[ξ = 0: fully discharged; ξ = 1: fully charged] [η = 0: fully charged; η = 1: fully discharged] + − Anode:
C6 + ξLi + ξe −−→ Liξ C6 Anode:
Li1−η C6 − (1-η) Li+ − (1-η) e− −−→ C6 Cathode: LiFePO4 − ξLi+ − ξe− −−→ Li(1−ξ) FePO4 Cathode: Liη FePO4 +(1 − η) Li+ +(1-η) e− −−→ LiFePO4 Overall: C6 + LiFePO4 −−→ Liξ C6 + Li(1−ξ) FePO4 Overall: Li(1−η) C6 + Liη FePO4 −−→ C6 + LiFePO4 ξ = 0:
C6 + LiFePO4 (fully discharged) η = 0:
LiC6 + FePO4 (fully charged) ξ = 1:
LiC6 + FePO4 (fully charged) η = 1:
C6 + LiFePO4 (fully discharged) [Dr A.E. Dahoe: Principles of Hydrogen Safety, Knowledge Center for Explosion and Hydrogen Safety, Dutch Armed Forces]

12

is, therefore, important to investigate technical solutions for this increase in volume and weight. One of these solutions is the use of a volume-exchange tank. In this tank two or more fuels are stored, where the inner tanks change in volume. During the trip the spent-fuel tank becomes bigger and the fuel tank smaller.
The V2 version of the prototype is being developed and will have a capacity of 3.75 kg H2 per hour or 125 kW and will function using a catalyst. The reactors demonstrate the viability of the technology in a Such a tank system is researched by Kim Taegyu, who analysed a system as is illustrated in Figure 2.7 [34].
relevant environment meaning that they have a technology readiness level (TRL) of 6. When integrated This application has a maximum power output of 100 W from the PEMFC and has a storage capacity of 107.8 with a fuel cell the technology will show its viability as part of an integrated system reaching TRL 7. The reactor volume and specifics will increase further when developed, however, for now, these specifics W · h with 200 gr of 15 w t % N aB H4 and a Co-B catalyst. A rubber bag is designed in the tank to store the of the V2 reactor will be used as a basis for the design of the propulsion system.
spent-fuel, like shown in the figure. As is concluded from this research the volume-exchange tank in this Internal External Capacity Power Density Reactor TRL Pressure Temperature configuration improved the volumetric density, and on top of that the gravimetric density. After all, two tanks volume volume (kg H2 /h) (kW H2 ) (kW/L) 4 V1 38 L 49 L 0.15 5 0.10 5-6 50 bar 60-110 C are heavier than one volume-exchange tank. Other advantages are that the effect of sloshing and the change V2 38 L 49 L 3.75 125 2.55 6 110 bar 60-110 C in center of gravity were minimised [34]. These advantages will also be applicable when a scale-up system Table 2.5: Specifications of the reactor prototype versions one and two developed by H2FUEL.
on-board of a vessel is implemented.
2.2. Hydrogen generation system

17

NaBH (SODIUM BOROHYDRIDE, SODIUM TETRAHYDRIDOBORATE)

(a) V1 prototype

Laboratory prototype [10].

(b) Scheme for multipurpose batch reactor

Figure 2.7: Operation concept of a volume-exchange fuel tank for a small UAV (unmanned aerial vehicles) [34]

Figure 2.4: The V1 prototype of a NaBH4 batch reactor build en tested by H2FUEL (a), Multi purpose batch reactor using dry fuel [26] (b)

Operational concept [11].

Another example of a volume-exchange tank is the one suggested by H2Fuel-systems, shown in Figure 2.8 [64]. In their concept 3 compartments can change in volume due to flexible inner tanks. This design can be The NaBH4 can be delivered and stored in different solutions. Four storage methods for the NaBH4 fuel applicable on a system where acid as an activator is used, stored in the third compartment. Two situations are defined as: Fuel 30, Fuel 50, Fuel 66 and Dry fuel. The number indicates the weight percentages DEHYDROGENATION of NaBH4 in the solution and dry fuel is a substance of small powder or crystals that can be mixed with are shown in this figure. One where the spent-fuel volume is maximised and the vehicle needs to re-fuel, water to achieve the desired solution for the reaction. In this section the different fuels will be shortly evaluated, in table 2.6 the gravimetric and volumetric densities are calculated based on 1 kg of H2 and Hydrolytic:
Catalytic:
and one when no fuel is consumed yet [64]. In maritime application this tank will improve the volumetric assuming a lower heating value (LHV) of 33 kWh, efficiency losses are neglected. Furthermore, NaOH accelerator and gravimetric energy density when an acid accelerator isacid used.
A disadvantage of this system is the safety is not added to the solution yet since the precise percentages may differ and will increase the weight NaBH4 + 2 H2 O −−→ NaBO2 + 4 H2 NaBH4 + 2 H2 O −− −−−− −−→ NaBO2 + 4 H2 and volume per kg H2 .
H2 SO hazard of storing an acid and a sodium borohydride solutionHCl, in one tank.
4 Sodium borohydride catalystthe safety hazard of the previously menA new concept design is herein proposed, which overcomes Fuel 30 is based on a mole ratio of 1 NaBH4 to 5 H2 O so that enough water is present after the NaBH4 + (2 + ξ) H O −−→ NaBO2 + 4 H2 + ξH2 O NaBH4 + 2 H2 O −−−−−→ NaBO2 + 4 H2 hydrolysis reaction for the NaBO2 side product to dissolve and thus prevent precipitation2in the reCo-Ru-Ni tioned tank. This concept is depicted in 2.9. In this concept a dry fuel- spent-fuel volume-exchange tank is actor that could clog the system or contaminate the catalyst. The gravimetric density can easily be determined since the solution is based on weight percentage. The volumetric density, however, suggested.
is The shaded and technical view shows a bag in the top of the tank where the spent-fuel is stored in a solid or liquid condition. Under this bag a moveable membrane lifts the weight of the spent-fuel. The rest of the tank is the space for the dry fuel in the form of a funnel to control the amount of fuel added to the water flow system under the storage tank. In this concept, gravity is used to handle the dry fuel. Another option would be to handle the dry fuel pneumatically.
Sodium metaborate 2.2.5. Fuels

In the scenario where a volume-exchange tank is used the volumetric and gravimetric density of the system will change. The size and weight of the tank will be dependent on the most voluminous fuel stored in the tank. At room temperature, the density of dry N aB H4 is 1.07 g /ml . For 1 gram, 0.97 ml inner storage volume 13 of N aB H (0.0264 mol) and, from the hydrolysis reaction, 1.74 grams of N aBO (0.0246 is needed. One gram 4 2 mol) is needed. N aBO 2 has a density of 2.46 g /ml , so for each gram of N aB H4 a volume of 0.71 ml is needed for the spent-fuel. This means the spent-fuel becomes heavier and less voluminous in dry conditions.

2.2. Principles of Alkaline Electrolysis Cell (AEC)

racted from the cell.
ated protons migrate
de (usually made of nanoparticles) where e external DC power ding to the half-cell

The design and layout of an Alkaline Electrolysis Cell (AEC) is shown in Fig. 2. The anode and cathode are immersed in a liquid electrolyte and a diaphragm (which is used to prevent the mixture of evolving gases (H2 and O2) is placed between the two electrodes. The electrolyte is usually a 25–30 wt% aqueous solution of potassium hydroxide (KOH). It is usually C. Lamy and P. Millet

ELECTROLYZERS

Journal of Power Sources 447 (2020) 227350

C. Lamy and P. Millet

Proton Exchange Membrane Electrolyser

Journal of Power Sources 447 (2020) 227350

Alkaline Electrolyser

Anion Exchange Membrane Electrolyzer

Fig. 3. Schematic diagram of an Anion Exchange Membrane Electrolysis Cell (AEMEC).

Fig. 2. Schematic diagram of an Alkaline Electrolysis Cell (AEC).
membrane electrolysis cell (PEMEC) and of a proton exchange membrane fuel cell (PEMFC).

Fig. 3. Schematic diagram of an Anion Exchange Membrane Electrolysis Ni/CeO2–La2O3 deposited on a microporous carbon paper) are used at Cell and (AEMEC).
pumped through the cell to collect the bubbles of gaseous products Fig. 2. Schematic diagram of an Alkaline Electrolysis Cell (AEC).
the cathode for the HER. Water is circulated through the cathode side to extract the excess of heat. Alternatively, natural circulation (so-called where it is reduced to form hydrogen and hydroxyl ions by the addition pump-lift) resulting from temperature gradients and buoyancy effects of on a microporous carbon paper)supply.
are used at Ni/CeO2–Laof2Otwo electrons coming from an external DC power Hydroxyl 3 deposited pumped through the the cellgas to collect of gaseous products in and bubbles the can bubbles be used but only for operation the low current ions migrate across the anionic membrane up to the the cathode anode, while the the cathode for the HER.
Water is circulated through side density The electrolyte is stored in two separated to extract the excess of heat.range.
Alternatively, natural circulation (so-calleddrums, one for electrons to areform transported to the cathode through thebyexternal circuit. In where it is reduced hydrogen and hydroxyl ions the addition each temperature gaseous product (O2 orand H2)buoyancy which also serveofas gas-liquidpump-lift) resulting from gradients effects the anode chamber, the hydroxyl ions are oxidized into water and ox­ separators. After drying, the typical purity of gases is of in two the electrons coming from an external DC power supply. Hydroxyl gas bubbles canof beHydrogen used but only forKnowledge operation inCenter the low current ygen by loosing electrons. Oxygen bubbles are released from the surface [Dr A.E. the Dahoe:
Principles Safety, for Explosion and Hydrogen Safety, Forces] 99.5–99.9% range for H2 and in the 99–99.8% range for O2.ions Higher migrate across the Dutch anionicArmed membrane up to the anode, while the density range. The electrolyte is stored in two separated drums, one for of the anode. Both half-cell reactions require electrocatalysts to form and purity (above 99.999%) can be reached by using on-line catalytic gas are transported to the cathode through the external circuit. In electrons release the respective gases from the electrode surfaces.
each gaseous product (O2 (deoxidizer) or H2) which purifiers [18]. also serve as gas-liquidthe anode chamber, the electrochemical hydroxyl ions reactions are oxidized into water [19]:
and ox­ The partial are the following separators. After drying, the typical purity of gases is in the The half-cell electrochemical reactions are:

Source: Ref. [12].

3

ygen by loosing electrons. Oxygen bubbles are released from the surface 99.5–99.9% range for H2 and in the 99–99.8% range for O2. Higher 2H2O þ 2 e → H2 þ 2 OH cathodic reaction with Ec ¼ - 0.828 V half-cell reactions require electrocatalysts to form and 2H2O þ 2 e → H2 þ 2 OH cathodic reaction with Ec ¼ - 0.828 V of the anode. Both purity (above 99.999%) can be reached by using on-line catalytic gas vs. SHE (2a) vs. SHE (2a) the respective gases from the electrode surfaces.
release purifiers (deoxidizer) [18].
2 OH → ½ O2 þ H2O þ 2 e anodic with Ea ¼ þ 0.401 V reactions arereaction the following [19]:
2 OH → ½ Oreactions 2 e anodic reaction with Ea ¼ þ 0.401 V The partial electrochemical 2 þ H2O þ are:
The half-cell electrochemical vs. SHE (2b) vs. SHE

H2 O ​ →H2 ​ þ

(2b)

14

2H2O þ 2 e → H2 þ 2 OH cathodic reaction with Ec ¼ - 0.828 V leading to the overall reaction:
vs. SHE 0 ​ ½ ​ O2 →with Urev ¼

​ Ea

(2a)

2H2O þ 2 e → H2 þ 2 OH cathodic reaction with Ec ¼ - 0.828 V leading to the overall reaction:
vs. SHE 0 H2 O ​ →H2 ​ þ ​ ½ ​ O2 →with Urev ¼ Ea

Ec ¼ 1:229 V � 1:23 V 2 OH(1) → ½ O þ H O þ 2 e 2 2

Ec ¼ 1:229 V � 1:23 V

anodic reaction with Ea ¼ þ 0.401 V

(2a)

(1)

S. Shiva Kumar and H. Lim

Fig. 5. (a) HER Polarization curves of CPN@TC, CP@TC, CP@NF, NF, CPN@NF and TC@NF (b) Tafel plots (c) comparison of CPN@TC with reported electrocatalysts (d) Long-term chronopotentiometry results of CPN@TC at different current densities (−10, −20, −40, −60, −80 mA cm−2 ) and durability polarization curves for CPN@TC before and after 3000 cycles (e) Calculated H2 O adsorption energy. (f) H* adsorption energy (Lv et al., 2021).
Energy Reports 8 (2022) 13793–13813

S. Shiva Kumar and H. Lim

S. Shiva Kumar and H. Lim
Energy Reports 8 (2022) 13793–13813 Fig. 6. Schematic view of AEM(AEM) water electrolysis working principle.
3. Schematic illustration of [13].
alkaline water electrolysis working principle.
Alkaline Fig.
water electrolysis Anion Exchange Membrane water electrolysis [13].
Energy Reports 8 (2022) 13793–13813

stainless
separator
are used as bipolar and end plates NiFeOOH on activated carbon fiber paper (CFP) by single-step (2021) developed an efficient bifunctional nano heterostructure activity with a lower cell voltagesteel of 1.94 V at plates the operating −2 (Pushkareva et al., 2020).
co-electrodeposition techniques and their performance in 1M electrocatalyst of NiCo-NiCoO2 @Cu2 O@CF for overall water splitcurrent density of 1 A cmrespectively .
ting and studied their performance in 1M KOH solution. As Further, Jin et al. (2021) have synthesized N-doped carbon KOH solution. The developed 3D-a-NiFeOOH/N-CFP electrode has Research and development(Ni-Moof AEM water electrolysis prepared NiCo-NiCoO2 @Cu2 O@CF electrocatalyst has shown imsupported Ni-Mo-O/Ni4 Mo3.2.3.
nanointerface electrocatalyst shown a better electrochemical performance with an overpotenAEM water electrolysis technology is under the developmental proved electrochemical performance towards the HER and OER O/Ni4 Mo@NC) by electrodeposition–calcination–electrodeposition tial of only 170 mV at a current density of 10 mA cm−2 and a up to the kW scale.
Globally, several research organizain alkaline media with a lower overpotential of 133 and 327 mV techniques and studied stage their electrocatalytic activity towards smaller Tafel slope of 39 mV dec−1 and outstanding stability in tions/institutions actively working to achieve a current density of 10 mA cm2 with a small Tafel the hydrogen evolution reaction in alkalineare solution (1M KOH). on the development of 1M KOH solution, as shown in Fig. 7. This enhancement is due AEM water electrolyzers, some of the AEM water electrolyzer slope of 119 and 118 mV dec−1 for HER and OER respectively.
The synthesized Ni-Mo-O/Ni 4 Mo@NC electrocatalyst has shown to the unique 3D structures with increased active sites and the are listed of in Table 4. However, sevIn addition, experimentally studied their performance through a higher electrocatalytic manufacturers/developers activity with a lower overpotential enhanced electrical conductivity that helps enhance the OER kieral innovations/improvements are still single-cell electrolysis process using NiCo-NiCoO2 @Cu2 O@CF as 61 mV at a geometric current density of 10 mA cm−2 , which is needed to scale up this netics and mass transport properties. In addition, Fe-doping plays technology for commercial applications.
The major challenges are a bifunctional electrocatalyst for both HER and OER. The re50% lower than that of Ni-Mo-O (120 mV) due to the introduction a key role in enhanced OER activity of 3D-a-NiFeOOH/N-CFP. Adstability (at present 35,000(1M h and targeted stability of sults showed better electrochemical performance than the other of N-doped carbon layers.limited Also, studies in neutral conditions ditionally, the developed 3D-a-NiFeOOH/N-CFP electrode OER ac1,00,000 h) and high hydrogen production cost, present hydrogen non-noble metal electrocatalysts, the attained cell voltage of PBS solution) Ni-Mo-O/Ni4 Mo@NC shows an overpotential of < tivity was studied in a single-cell alkaline AEM water electrolyzer −2 production cost is USD 1279 kW/H (2020), and the targeted 2 1.69 V to reach the current density ≥10 mA cm . Further, 60 mV, which is lower than that of Ni-Mo-O (∼100 mV). The with ultra-pure water and compared with commercial IrO2 elecreduction of USD ≤ to 300bekW/H 2 (2050) (Ionomr, 2020). To the developed electrocatalyst was stable during the continuous Tafel slope of Ni-Mo-O/Nicost Mo@NC is determined 99 mV 4 trodes under similar experimental conditions. Impressively, the achieve these targets, the existing challenges need to be ad−1 electrolysis process of 12 h in a strong alkaline solution due to dec , which is relatively lower than that of Ni-Mo-O (135 mV developed 3D-a-NiFeOOH/N-CFP electrode exhibits superior elecdressed economically to commercialize the robust mechanical adhesion between NiCo-NiCoO2 nanopardec−1 ). Lv et al. (2021) introduced multi-heterostructure inter- for market applications.
trochemical performance to commercial IrO2 electrodes, the atIn this direction, Thangavel et al.
(2021) developed a 3D oxygen ticles. The better performance was achieved by the small size of faces and 3D porous structures of Co2 P/N@Ti3 C2 Tx @NF as an evolution electrode via electrochemical integration of amorphous tained cell voltage of 1.88 V than commercial IrO2 2.08 V at NiCo-NiCoO2 nano heterostructures uniformly distributed on the efficient HER electrocatalyst for alkaline media. Initially, CPN@TC oxidized surface of copper foam enabling them to maximum utiwith multi-heterostructure interfaces were fabricated on the sur13800 lization active sites during the electrochemical reactions.
XuofetPEM al. (PEM) of water MXene (Ti NF by a two-step Fig. 13.
Schematic view of solid oxide water electrolysis working principle.
3 C2 Tx )-modified Fig. 9. Schematic view waterface electrolysis working principle.
Proton Exchange Membrane electrolysis [13].
Solidelectrodeoxide water electrolysis [13].
(2022) developed a highly efficient bifunctional electrocatalyst position method and subsequent nitriding process. The prepared of 2D metal–organic framework (MOF)-derived NiCoP nanoflakes Co @NF electrocatalyst performance was studied in blank LSM-YSZ electrode.
GDL Gas Diffusion Layer. PTL =Research Porous Transport 2 P/N@Ti 3 C2 Txand net-zero challenges. In addition, water electrolysis is a well1.3 V, which is water 3.3 times higher than the 3.3.3.
development of Layer.
pem electrolysis 3.3.1.
Working principle of pem = water electrolysis (NiCo for PEM overall water splitting in alkaline media.
The 1M PEM KOHwater solution, the results exhibited an outstanding HER per(nf) -P)the LMS = Lanthanum Manganite Strontium.
YSZ =Additionally, Yttrium Stabilized hydrogenZirconia.
generation rate of 873 mL cm−2 known electrochemical process for green hydrogen production During water electrolysis process, water is electroelectrolysis technology ishigher well developed and comdeveloped performance wereInstudied by threeformance with an overpotential of (MW) only 15 mV at introduced 10 and mA transcm−a2 novel electrode material h−1 . Zheng et al.
(2021) LSCF = Lanthanum Strontium Cobalt Ferrite.
chemically electrocatalyst split into hydrogen and oxygen.
this process, inimercially available up to megawatt for industrial that requires wider adoption to lower production costs with − 1 electrode assembly withmolecule linear sweep voltammetry (LSV) and a small Tafel slopesome of Mn-doped 30 mV large-scale dec , as shown in Fig.
5. La1.5 Sr0.5 NiO4+δ (LSNMx ) of Ruddlesden–Popper oxide tially at thecell anode side water is decomposed to generate portation applications, of the PEM electrolyzer high efficiency. Therefore, essential improvements and innova−1 method at the potential cycling rate of 2 mV s− in a 1M KOH In addition, shown superior stability during the 3000 cycles of + and their 4.
performance was evaluated in solid oxide electrolyzer oxygen (O manufacturers are listed in Table However, several improvetions are required to produce viable green hydrogen and meet 2 ) and protons (H ), and electrons (e ). The generated electrolyte solution.
The developed NiCo -P was shown better CV tests and only 20 mV shifting can be at the current density (nf) asreduce an oxygen electrode. production The LSNM0.cost, 5 showed lower resistance of oxygen eliminated from the anodic surface and the remaining ments are still −required to the hydrogen the global net-zero challenges. In this context, various water 2 2 ◦ − 2 electrocatalytic activity with a lower onset potential of 37 mV and of mA cm . In addition, (∆Ga∗Hcurrent ) and density of 500 mA cm 0.488 water  cm at with 2O protons are traveled through the proton-conducting membrane the100 present hydrogen production costdissociation is 800 USD C 700–1400 kW/H electrolysis technologies and their challenges, and possible solu◦ 15calculated by DFT2 1.435 V than commercial 5% Pt/C (43 mV) and IrO (1.504 V) at hydrogen adsorption ( ∆ G ) energies were 2 C with electrocatalytic activity during the ∗H1.4 V at 800 to the cathode side and the electrons are traveled through the (2020), and targeted costatreduction is USD ≤ 200stable kW/H 2 (2050) tions are given below for cost reduction and commercialization −2 the current density mV cm HER and (density functional theory) materials. According to in Fig. 14. This current 145for h different continuous as shown external circuit to of the100 cathode side.towards At the the cathode side,OER.
the (IRENA, 2020b). To achieve this target, theoperation, existing challenges perspective.
In addition, NiCo -P was shown lower overpotential of 119 mV the DFT calculations, the prepared CPN@TC has strongest binding density is 85.2% higher than the un-doped LSN electrode.
(nf) protons and electrons recombined to produce H2 gas. The basic need to be addressed such as replacement/reduction of platinum and 315 mV than commercial 5% Pt/C (291 mV) and IrO (400) to energy of − 0.822 eV, which is favorable for the HER reactions.
Vibhutransition et al. (2021) developed layered Alkaline water electrolysis principle of PEM water electrolysis is shown in Fig. 9. 2 group metals with cost-effective metals, removing the perovskite-based rare −2

ELECTROLYZERS – RISK ANALYSIS (HAZID, RISK MATRIX)

WITHOUT SAFETY MEASURES
Likelihood

(i)

(ii)

(iii)

WITH SAFETY MEASURES
Likelihood

(iv)

(i)

(ii)

(iii)

(iv)
RISK LEVEL
High

(V)

18

1

22

(V)

40

2
Medium

(IV)
Severity

Severity

(IV)

(III)

(II)

(I)

2

3

44

Low

(III)

4

18

(II)

21

3

2

23

(I)

19

6

3

Modification of the Risk Matrix according to Ref. [14].

[Dr A.E. Dahoe: Principles of Hydrogen Safety, Knowledge Center for Explosion and Hydrogen Safety, Dutch Armed Forces]

16

ELECTROLYZERS – RISK ANALYSIS (HAZID, RISK MATRIX)

Severity and likelihood criteria according to Ref. [14].

Severity ranking criteria
V

Severe damage to building and
facilities outside the site Fatalities outside the site IV Significant damage to building and facilities outside the site Fatalities inside the site III Moderate damage to building and facilities outside the site Injuries outside/inside the site II Minor damage to building and facilities outside the site Minor injuries outside/inside the site I Negligible damage to building and facilities outside the site Negligible injuries outside/inside the site

Blast pressure
(kPa)
> 34

Jet flame
length (m)
>6

> 100
6.9 – 34

>6
–

> 100
3.4 – 6.9

2–6
–

16 – 100
1 – 3.4

–
1–2

2 – 16
<1

0.3 – 1
<6

<2

< 0.3

Likelihood criteria
i
Once per 1000 years
ii Once per 100 years iii Once per 10 years iv Once per year FMEA failure mode Hydrogen embrittlement Hydrogen assisted cracking Corrosion Stress corrosion cracking Fatigue Loosening of threaded joints Weld defect Sealing deterioration Seat/gland leakage Polymer electrolyte damage

[Dr A.E. Dahoe: Principles of Hydrogen Safety, Knowledge Center for Explosion and Hydrogen Safety, Dutch Armed Forces]

17

losie en brand bij een Noors waterstoftankstation:
dracht en leerstof swaterstaat

swaterstaat

GASEOUS HYDROGEN STORAGE – EXPLOSION HAZARDS

UARI 2020
EMBER 2019

Kjorbo, Norway
Monday 10 June 2019 at 17:30 h
Hydrogen Explosion (3.0 – 3.5 kg H2 ) Glass damage at 60 – 70 m distance LESSEN KJØRBO-INCIDENT OfficeVANatHET60 m distance Houses at > 225 m distance

Figuur 15: Impressie schade intern.

De bovenstaande foto toont de eindtoestand. In het volgende hoofdstuk gaan we in op de toedracht en op de processen direct na de lekkage tot aan de eindtoestand.

3.2

18 door de brandweer
Repressie

Door de commandant, de heer Sverre Junker van de lokale brandweer, is een uitgebreide terugkoppeling gegeven tijdens de persconferentie op 28 juni 2019 in Oslo [zie referentielijst]. Wij beschikken over de videoopname, maar de spreker heeft zijn verhaal in het Noors verteld. Uit de sheets van hem zijn diverse zaken

DELFT UNIVERSITY OF TECHNOLOGY – GREEN VILLAGE Explosion involving 3.5 kg hydrogen Blast calculation according to Ref. [15].
70

>7
6
5

35

4.5

70

52.5

35

17.5

-17.5

-35

-52.5

-70

17.5

Distance [m]

-17.5

Overpressure [kPa]

Distance [m]

52.5

4
3.5
3
2.5
2

-35

1.5
-52.5

<1

Deflagration

-70
70

> 250
200
150

35

100

Distance [m]

-17.5

70

52.5

35

17.5

-17.5

-35

-52.5

-70

17.5

Overpressure [kPa]

Distance [m]

52.5

70
50
40
30

-35

20
15

-52.5

< 10

Detonation

-70

19

PRESSURE EFFECTS ON PEOPLE, STRUCTURES AND EQUIPMENT

Entry
1

Overpressure
(kPa)
190

2

69–76

3

70

4
5

60
55

6
7
8
9
10
11

50–55
50
40–45
35–40
20–40
35

12
13
14
15

30–35
30
20–28
24

16
17

15–20
20

18

18

Damage/injury
Occupants of unstrengthened building will be killed by direct action of blast, by being struck by building debris, or by impact against hard surfaces [16].
Occupants of unstrengthened building are expected to suffer severe injuries or death from direct blast, building collapse, or translation [16].
Probable total destruction of buildings; heavy machine tools moved and badly damaged [17].
Loaded train boxcars completely demolished [17].
Occupants of unstrengthened building will be killed or incur serious injuries by blast to eardrums and lungs, by being blown down or struck by fragments and building debris [16].
Unreinforced brick panels, 25–35 cm thick, fail by shearing or flexure [17].
Loaded tank cars/train wagons overturned; brick walls, 20–30 cm thick, collapse [17].
Collapse of pipe bridge [17].
Displacement of pipe bridge, failure of piping [17].
Large trees fall down [17].
Breakage of wooden telephone poles; most buildings destroyed, except for concrete reinforced shear wall buildings; platting of cars and trucks pressed inwards [17].
Near-complete destruction of houses [17].
Cladding of light industrial buildings ruptured. Panelling torn-off [17].
Frameless, self-framing steel panel building demolished; rupture of oil storage tanks [17].
Personnel injuries of a serious nature or possible death are likely from fragments, debris, firebrands or other objects. There is a 10% chance of eardrum rupture [16].
Unreinforced concrete or cinderblock walls shattered [17].
Heavy machines in industrial buildings suffer little damage; steel frame building distorted and pulled away from foundations [17].
Lower limit of serious structural damage; 50% destruction of brickwork of houses [17].

20

Table 1: Continued.

19

16

20
21

15
7–15

22
23

10
5.9–8.3

24
25
26
27
28
29

8
7
3.5–7
5
3
2

30
31
32
33
34

1
0.7
0.3
0.2
0.15

Personnel may suffer temporary hearing loss or injury from secondary blast effects such as building debris and the tertiary effect of displacement. No fatalities or serious injuries from direct blast are expected [16].
Partial collapse of walls and roofs of houses [17].
Corrugated asbestos shattered. Corrugated steel or aluminum panels fastenings fail, followed by buckling; wood panel fastenings fail, panels blown in [17].
Steel frame of clad buildings slightly distorted [17].
Personnel are provided a high degree of protection from death or serious injury with injuries that do occur being principally caused by glass breakage and building debris [1].
Partial demolition of houses, made uninhabitable [17].
Collapse of roof of a tank [17].
Windows usually shattered; occasional damage to window frames [17].
Minor damage to house structures [17].
Limited minor structural damage [17].
Probability of 0.95 of no serious damage beyond this value; some damage to house ceilings;
50% of window glass broken [17].
Typical threshold for glass breakage [17].
Breakage of small windows under strain [17].
Loud noise similar to sonic boom; occasional glass failure [17].
No structural damage; occasional breaking of large window panes already under