3.

Summary of Fiscal Year 2001 Results

3.1

Task 1

Study of System evaluation

Toward the hydrogen energy society in the future, the introduction and penetration
scenario of hydrogen energy combined with the fuel cell introduction scenario were
examined and.cost analysis of fuel cell systems was performed by the learning curve
for making the scenario.
As for making the introduction scenario of fuel cell, a maintenance strategy ofhydrogen refueling stations in accordance with progress and penetration of fuel cellvehicles by each vehicle type and region was examined. Additionally future costs offuel cell vehicle and hydrogen refueling station were analyzed by the learning curveand economical efficiency was examined. For stationary fuel cell systems, economical
efficiency and carbon benefit by indroducing of fuel cell systems for household were
evaluated for making an introduction scenario. Additionally, as for a penetration
scenario of hydrogen energy, economical efficiency and possibility of supply anddemand of hydrogen energy producing by renewable energy were examined by thelong-term energy model.
3.2

Task ２

Study of Safety Measures

While hydrogen has risks for fire and deflagration, we do not have enoughexperiences in handling it at small-scale and dispersed facilities such as fuel cellvehicles and hydrogen refueling stations. New safety measures should be taken andexisting standards and regulations should be re-examined in order to realize
installing and operating facilities for production, storage and refueling of hydrogen intowns. So, this task of WE-NET program is aiming to prepare a safe design guideline
or a basis for re-examining regulations through carrying out experiments, collecting
data on hydrogen behavior and characteristics in leakage, diffusion, self-ignition,
flame and deflagration and assessing the hazard risks on the facilities. The maximum
overpressure from hydrogen deflagration of stoichiometric mixture without any
obstacles was below the safety criteria at 10 m distance from the gas mixture.
However, the maximum overpressure exceeded one from methane stoichiometricmixture by a factor of 10. Hydrogen effluence from high pressure through a pinhole
did not ignite by itself. Both the length and width of the flames of hydrogen fromhigh pressure were proportional to the diameters of pin holes.

VII

3.2

Task ３

Review and Investigation for International Cooperation

WE-NET project meant a research and development project subject for broad
aspects in utilization of hydrogen, which can be achieved through international
cooperation. Thus it is vital that the whole concept of the project should be wellunderstood by overseas governmental organizations and other organizations that are
involved in the development of hydrogen energy in order to seek their positive
cooperation.
Terrorist’s attack in New York in September, 2001 certainly adversely affected
WE-NET activities due to cancellation of international conferences and seminars or
difficulty for participation, etc. However, major activities in this year such aspresentation in international conferences(The 11 th . General Assembly of CanadianHydrogen Association, Hypothesis IV, Japan/Korea Symposium, etc.), cooperation
with International Energy Agency and developing Part II of the videotape on thesafety of hydrogen are conducted.
Regarding

rationalization

in

terms

of

ISO/TC197,

while

participationforinternational conference from Japan has been made only twice in fiscal year 2001 due
to an influence of terrorist’s attack in September, collaboration to the organization
has been continuously underway by submitting reports to various ISO/TC197
secretariats.
In 2001 year, ISO/TC197 registered WG-8 「 Hydrogen generators using waterelectrolysis process」.as new item and Japan has also registered in this WG-8.
3.4

Task ４Development of Power Genaration Technology

A 100kW class single cylinder test engine for an open-cycle hydrogen combustion
engine was constructed. And a laboratory building for the testing of the hydrogen
combustion engine was constructed and test facilities were installed in the laboratory.
A preparation of test for a single cylinder test engine was completed.
Meanwhile, the possibility of the self-ignition of a hydrogen combustion engine with ahigh compression ratio, measures to improve thermal efficiency and NOx Reduction
Measures were investigated. And a test was conducted to confirm the proper
functioning of the hydrogen injection unit that was made in FY 2000 for theexperimental single cylinder diesel engine and test data were got. Results will bereflected in design of the hydrogen injection unit.
As for the numerical analysis, in order to study the conditions for self-ignition ofhydrogen under the air open cycle, combustion analysis of hydrogen jets was conducted.
In order to conduct the numerical simulation of the combustion process of the hydrogenVIIIjet, a combustion analysis model was conducted, and the calculated results werecompared with the laboratory test results to verify the model. As a result it was
concluded that the analysis of hydrogen jet combustion for actual engines is feasible.
3.5

Task ５Development of Hydrogen Fuel Tank System

Based upon the result of rapid filling test for mini-sized MH (Metal Hydride) tanks
performed in fiscal 2000, we designed the divided chamber type tank and plate-fin
type tank of full size and manufactured experimentally one tank for each type.
We carried out rapid filling tests at the natural gas reforming type hydrogen
refueling station in Osaka with the divided chamber type tank and at the PEM
electrolysis type hydrogen refueling station in Takamatsu with the plate fin typetank. We achieved filling times of 9.3 minutes and 9.1 minutes for hydrogen of 25
Nm 3 at the reforming type and electrolysis type hydrogen refueling stations, within
10 minutes as the target.
The fire-resistance test was conducted for MH tanks with a fusible plug, which
released the internal pressure entirely by melting as temperature increased, and aspring type relief valve as measure for prevention destruction of tanks by heating. It
was ascertained that we could prevent an abnormal rise in pressure of the tank,deformation and burst of the container by using a spring type relief valve and afusible plug together.
With mini-scaled tanks, we tried to clarify degree of effects of various factors on
deformation with attention to the structural factor, filter structure, honeycomb
structure and separation plates inside tanks. It was proved that the tank with thestructure having separation plates and honeycomb combined with plate filter had
smaller strain than the tank without it. No crack was found in tanks with tube
filters.
3.6

Task ６Development of PEFC Utilization Pure hydrogen

In order to verify the reliability, a long term operation test was conducted by a cell stack
manufactured by FY 2000 specifications. Test data show a stable performance even after 7,000
hours. In addition, a long term test using a cell stack with FY 2001 specifications wascommenced. After more than 1,500 hours of operation, test data show a stable performance too.
Meanwhile, the results of the start-stop test were satisfactory.
For their integration to a 30 kW class plant, four 170 cells stacks and one 120 cells stack
were manufactured as the main and the subordinate stacks, respectively. Moreover, the mass

IX

and heat balances of power generation plant were calculated. And the package was designedwith its optimum arrangement to ensure compactness, maintainability and safety
requirement. The assembly of a power generation plant package was almost completed.
As for the applicability of the dehumidification system by hollow fiber membrane(polymer film) to an actual equipment was examined. As result the hydrogen gas
humidity control system by the hollow fiber was designed and the component
specifications were decided. Moreover peripheral components specifications for theplant were examined and decided.
3.7 Task ７

Development of Hydrogen Refueling Station

For the natural gas reforming type hydrogen refueling station, the remaining
component equipments, such as PSA equipment, metal hydride type of storage
equipment, gas storage unit and high pressure dispenser unit, were manufactured.
The construction of the station was completed by installation and trial running ofcomponent equipments. The designed performance was ascertained through unit andcoupled operation of equipments. A rapid filling test to MH model tank (separated
chamber type) was conducted. It was ascertained that the target performance offilling hydrogen of 25Nm 3 in ten minutes was satisfied. We filled hydrogen up to thepressure of 25MPaG in four minutes by cascade system using high pressure modeltank. It was ascertained that the heating characteristics of the tank due to adiabatic
compression did not exceed beyond the safe level.
For the PEM water electrolysis type hydrogen refueling station, the remaining
component equipments, such as PEM water electrolyzer and compressor, were
manufactured. A remote watching system that the station operation data wastransmitted from the central control board inside the station yard with wireless LAN
was established. The construction of the station was completed by installation andtrial running of component equipments. The trial filling tests combined with thestation and model tanks were carried out. As for filling test of hydrogen up to
25MPaG and 35MPaG, it was confirmed that hydrogen of 30Nm 3 was filled into themodel tank safely within 5 minutes. As for filling test into the metal hydride modeltank(plate-fin taype), it was confirmed that hydrogen was filled into the tank safely
within 9 minutes. Safety issues about two types of the hydrogen refueling stations
were examined. For safety measures adopted for these stations, fundamental
philosophy for safety and mounting locations for sensing devices were investigated.
The design review and on-site review on safety measures adopted for these stations
by the Task 2 were finished with no problems.

X

3.7AB Task ７AB

Development of Hydrogen Refueling Station

The object of this research and development project is to develop a hydrogen refuelingstation, into which hydrogen is transported from the outside the station (off-site
system). The salt electrolysis plants are source of hydrogen for off-site systemhydrogen refueling stations. There are 35 plants in 27 companies dispersed all over
the Japan. The annual hydro0gen production in fiscal 2001 was about 1.2 billion Nm 3 ,and a considerable amount of hydrogen supply is expectable already at the moment.In
fiscal 2001, we completed the design of the entire system for the hydrogen refuelingstation using hydrogen trailers as the hydrogen source. The specification and designof the component apparatuses were also accomplished. We started to manufacturesome apparatuses. The investigation on a layout of the station site and installation ofutility equipment were made. Further, we developed a dispenser and studied thetechnology for filling control of hydrogen.
3.8 Task ８

Development of Hydrogen Production Technology

Along with the development of large area electrolysis cell lamination (electrolysis
area 1,000cm ２

10 cells) and continuous operation of the electrolyteforcommercialization of production technology , manufacturing of electrolysis cell forhydrogen refueling station in connection with the Task 7(the development ofhydrogen refueling station) was implemented. Initial testing was carried out.
And, also, a few different type of high temperature resistant molecule electrolytic
membranetobeusableinhightemperature

have

been

manufactured

andevaluated its ion conductivity and electrolysis performance.
3.9 Task ９(1)

Development of Hydrogen Transportation and Storage Technology

Development of Liquid Hydrogen Transportation and Storage Facilities

Continuing from last year, we conducted insulation performance tests andlow-temperature strength tests to develop a design database on thermal insulation
structure for large-scale storage.
Small-capacity liquid hydrogen transportation and storage system was studied for the
purpose of supplying hydrogen to hydrogen stations. In the study, conceptual designof tanks with capacity of 30m 3 and 15m 3 were produced. And a marine transportation
system was studied with Tokyo Bay area as a model case of medium-sized hydrogen
supply.
(2)Development of Devices for Common Use

XIWe evaluated hydrostatic bearing, which is a non-contact bearing similar tomagnetic bearing, by bearing rotation test for application in small-scale liquidhydrogen pumps. Then, we carried out the basic plans for pump specifications, motor
specifications and bearing specifications.
Also, we conducted studies on recovery and utilization of boil-off hydrogen gas
generated during storage on a hydrogen station. Consequently, re-liquefaction was
found to be very inefficient. On the other hand, it was found that boil-off hydrogengas yielded sufficient power to cover power consumption for the entire station whenused as fuel for fuel cells, and also it would be effective to supply as high pressurehydrogen gas to vehicles.
(3)

Conceptual Design of Hydrogen Liquefaction Facilities

We studied hydrogen expansion turbines for power recovery, and u t i l i z i n g t h e
cryogenic

heat

of

LNG

for

power reduction in h y d r o g e nliquefaction

machine.
We selected and reviewed radial turbine with three-dimensional rotor blades as
expansion turbine. Under the assumptions for this study, outer diameter of rotor
blades was under 40mm for 5t/d turbine on high temperature side as well as for 1t/d
turbine on high and low temperature sides, which are smaller than generally used
centrifugal turbo type hydrogen expansion turbines. There is a possibility here that
effects of leakage flow may relatively increase, so that actual performance may belower than the estimated performance based on calculation.
Utilizing LNG cooling is very effective in reducing required power based on result ofstudies.

3.10 Task １０

Development of Cryogenic Materials Technology

To evaluate the low temperature material used for liquid hydrogen transportation
andstoragevessels,material

propertyevaluation

tests

were

conducted

intemperatures ranging from the room temperature to low temperatures including thetemperature under liquid hydrogen environment. We have evaluated new welding
methods effective in improving toughness at a low temperature by expanding thescope of the metal types to be applied. This has led to the following findings:
Reduced pressure electron beam welding of stainless steel has been shown to provide
the same high toughness at a low temperature in high-strength SUS316NL as in

XIIother types of steel. No influence of hydrogen charging was observed.
Perfect γ -weld metal TIG welding method of stainless steel has also shown toprovide a high degree of toughness. No influence upon hydrogen susceptibility wasobserved.
The application of the friction stir welding to the A5454 aluminum alloy of
low-magnesium content has been found to ensure a drastic improvement in the
low-temperature toughness.
For aluminum alloys, we could also extend our knowledge on the strength/toughnessbalance by magnesium content.

3.11 Task １１Development of Hydrogen Storage Materials

In order to apply to mobile and stable hydrogen container, research anddevelopment for promising substances with the following WE-NET target are
performed.
- Effective hydrogen storage capacity:- Temperature for hydrogen desorption :- Durability

more than 3 mass%less than 100 ℃: hydrogen storage capacity more than 90 % of the initial
capacity after 5,000-cycle use

Works for improvement of capacity and endurance of V-base and Ti-Cr base alloys
developed in the previous year are put forward, and researches for next generation
alloys with more than 5 mass% capacity are commenced.
Two types of chemicals, such as hydrogen complex compound and naphtenes, arestudied as 5-8 mass% hydrogen storage materials that can be used repeatedly.
Following in the wake of last year ’s accomplishment of this working group, in
which we had established accurate measurement techniques, we investigatedhydrogen storage capacity in several carbon materials, including carbon nanotubes.

3.12 Task １２

Investogation and Study of Inovation & Leading Technology(1) Assessment of FY 2001 Feasibility Study Results
We conducted 6 feasibility studies as follows: ① A study on the storage ofhydrogen using an iron oxide as a medium ②A study on a hydrogen production
system by partial oxidation of biomass and waste used as raw materials ③
Search for new hydrogen-storing inorganic and organic composite materials ④
A study on gas turbine systems coupled with non-equilibrated methane

XIIIreforming process ⑤A technical study on a hydrogen storage system using new
decalin/naphthalene hydrogenation and dehydrogenation processes based on asuperheated liquid membrane method ⑥A study on the method of producing
hydrogen without generating carbon dioxide, using natural gas as raw
materials, and an assessment of by-products(2)Assessment of the Results of a Basic Study
We conducted 「 A Basic Study of the Magnetic Refrigeration Technology for
Liquefaction of Hydrogen」that had started in FY 2000.
We

manufacturedaregenerator

for

the

1 st

stage

and

examinedits

characteristics such as thermal conductivity. We are planning to manufacture
the world first 10kg/day prototype hydrogen liquefaction system based on themagnetic refrigeration method in the next fiscal year.
4.

Future Development
Research,basic investigation, studyof elementary

technologies,

and

other

investigations will be carried out continuously to obtain necessary information for the
optimum design of the total system, in order to confirm establishment of technologies
required to design and construct a pilot plant.

XIV