7.

Task 7Development of Hydrogen
Hydrogen Refueling Station

7.1

R&D Target

R&D target of hydrogen refueling station in the WE-NET phase II program is “todevelop and demonstrate a small scale of test system with hydrogen supply capacityof 30Nm3/h, equivalent to about one tenth of actual scale, in order to establish theelement technology and system technology of stand alone type of hydrogen refuelingstation for the purpose of fuel supply to hydrogen fuel cell vehicles”.
In the fiscal year of 2001, we designed in detail and manufactured the remaining
composing equipments for two types of hydrogen refueling systems (Natural gas
reforming type and PEM water electrolysis type), as in the fiscal year of 2000. We didconstruction work for components equipments of these hydrogen refueling stations
including utility facilities. A trial operation and tuning of the system were performed.
In addition, through an operation combined with a test tank, the system of hydrogen
refueling station was verified and filling technology was developed. We also
investigated and examined these systems to prepare the technical guidelines forseveral kinds of hydrogen refueling stations.
7.2
7.2.1

The result of R&D in 2001
Natural gas reforming type hydrogen refueling station

In fiscal year of 2001, we manufactured the remaining component equipments
according as detailed design done in the last fiscal year and built the hydrogen
refueling station. After completion of the station, we tuned up component equipmentsby combined operation and carried out filling test using model tanks.
(1) Total system
We installed all component equipments, constructed the whole system of hydrogen
refueling station including utility facilities and finished tuning operation for main
component equipments.
As a result of safety study for hydrogen refueling station, we install one earthquake
sensor and three fire alarms as additional safety devices. An automatic information
system activated by alarm was incorporated in the centralized control system as asafety measure in the operator’s absence.

.

(2) Reforming type of hydrogen production equipment
As for the reforming type of hydrogen production equipment, the design andmanufacturing of PSA equipment were performed and an investigation for packaging
the equipment was made from the viewpoint of safety. It was ascertained in aconfirmation test that its performance satisfied with original designed value. After
that, this equipment supplied hydrogen satisfactorily both in tuning operation for themetal hydride type storage equipment and high pressure hydrogen storage equipment‑52‑

and in operation experiments. The running time of 700 hours and hydrogen supply of
7,600Nm3 was achieved.
(3) Metal hydride type of storage equipment
Following the detailed design specification in the last fiscal year, we manufactured
the metal hydride (MH) type of storage equipment with an absorption rate more than
30Nm3 /h and a supply rate more than 150Nm3/h. Its performance was verified bytests both in single operation and in combined operation with the hydrogenproduction equipment and MH filling system.
(4) MH filling system
As for MH filling system, we installed the MH dispenser unit and cooling unit
manufactured in the last year and carried out performance test both in unit operationand in coupled operation together with the MH storage equipment and MH modeltank. It was ascertained that this system satisfied basic performance of fillinghydrogen of 25Nm3 in ten minutes, the target value.
(5) High pressure filling system
As for high pressure filling system, we installed the high pressure compressor
manufactured in the last year. The gas storage unit and high pressure dispenser unit
designed in the last year were manufactured and installed.
This system passed the inspection according to the High Pressure Gas Safety Law
after its completion. Consequently, it became legally possible to fill hydrogen of35MpaG to hydrogen vehicles in this station.
(6) Results of operation test
In fiscal year of 2001, operation tests on MH filling system using metal hydride
type of storage equipment and high pressure filling system were carried out.In thetest for MH filling system using metal hydride type of storage equipment, a rapid
filling test to MH model tank (separated chamber type) designed and manufactured in
Task 5 was conducted. It was ascertained that the target performance of fillinghydrogen of 25Nm 3 in ten minutes was satisfied. Figure 7.2.1-1 shows the change inflow rate and pressure of hydrogen with time. Though there was some variation inhydrogen flow rate, integrating flow increased linearly till hydrogen of 20Nm3 wasfilled, because pressure difference ( P) between the MH storage and the MH modeltank was held to be more than fixed value necessary to control flow. We obtained data
enable us to optimize the rapid filling condition, such as supply condition both forheat medium in the MH storage equipment and for coolant in the MH model tank.
In the test for high pressure filling system, we adjusted flow control of high pressure
dispenser using high pressure model tank. We filled hydrogen up to the‑53‑

Change in hydrogen flow rate, integrating flow and pressure with time1

Hydrogen flow rate
Pressure of MH storage
Integrating flow

0.8

HydrogenFlow rate：170Nm3/h
Brine
Flow rate：125L/min
Temp.：-13.3℃
MH storage heatmedium
Flow rate：360L/min
Temp.：72℃

15105Pressure at exit of dispenser

0.60.4Pressure [MPaG]

20
Integrating flow[Nm3]

Hydrogen flow rate（×10 [Nm3/h]）、

250.20002468101214Time [min]Fig.7.2.1Fig.7.2.1-1 Rapid filling experiment of MH filling system

Data on high pressure tank in filling at 25MPaG
100

25Pressure

90

20
Inside temperature

7060

1550
40

1030205Outside wall temperature

1000-101234567891011Time [min]Fig.7.2.1Fig.7.2.1-2 Rapid filling experiment of high pressure filling system‑54‑

Pressure [MPaG]

Temperature [℃]80

pressure of 25MPaG in four minutes by cascade system to study temperature changeof high pressure model tank. Figure 7.2.1-2 shows the behavior of temperature andpressure of the tank in filling up to 25MPaG. It was ascertained that the heating
characteristics of the tank due to adiabatic compression did not exceed beyond thesafe level.
7.2.2

PEM water electrolysis type hydrogen refueling station

The research in the fiscal year of 2000 was followed by detailed design andmanufacture of remaining component equipments, construction of PEM waterelectrolysis type hydrogen refueling station and operation test combined with modeltanks.
(1) PEM water electrolysis type hydrogen production equipment
We manufactured the main body of the equipment, control board, DC power supply
and finished to install on the refueling station site. A trial operation of the equipment
at the station site was conducted. It was confirmed that the performance satisfied
with a required specification value (pressure/ production volume/ purity).
(2) High pressure type filling system
The detailed design and manufacture of the compressor had been finished. Also, thetrial operation at 40MPaG by nitrogen and helium was carried out in themanufacturing factory. It was confirmed that the performance satisfied with arequired specification value (discharge pressure/ processing quantity). This system
passed the completion inspection based on the general rule of the High Pressure Gas
Safety Law in Japan and was permitted as the high pressure production equipment.
After that, the combination test of the compressor and the gas storage facilities wascarried out using hydrogen at the station site. It was confirmed that the performancesatisfied with a required specification value (discharge pressure/ processing quantity).
We also conducted an experiment of filling hydrogen to the model tank.
(3) Metal hydride filling system
The brine chiller was permitted as the production apparatus after submission of its
notification report, according to the refrigeration rule of the High Pressure Gas Safety
Law in Japan. On the refueling station site, the absorption and supply test of metal
hydride type storage equipment were carried out to confirm that the performancesatisfied with a required specification value (absorption time, supply pressure/time).
After that, using the model tank designed and manufactured in Task 5, we also
carried out the filling test of hydrogen.
(4) Remote watching system
We built a remote watching system that the station operation data was transmitted
from the central control board inside the station yard with wireless LAN, because‑55‑

buildings could not be constructed inside the yard according to the BuildingStandards Act in Japan. This system enabled us to watch the status of operation ofthe station and to collect the operation data.
(5) Operation test
As for the high pressure filling system, rapid filling test of hydrogen of 30Nm3 atpressure of 25MPaG and 35MPaG by combination of gas storage facilities anddispenser using high pressure test tank. As a result, it was confirmed that hydrogen
was filled into the tank safely within 5 minutes(Figs.7.2.2-1 and 7.2.2-2). As for themetal hydride filling system, rapid filling test of hydrogen of 30Nm3 was conducted bycombination of the metal hydride storage equipment, the brine chiller, and the MH
dispenser using the model tank(plate-fin type) designed and manufactured in Task 5.
As a result, it was confirmed that hydrogen was filled into the tank safely within 9minutes, just as the high pressure filling system.

Change of pressure and temperature of tank at 25MPaG
80

2570Pressure
Inside temperature

2050
40153020101005

Outside wall temperature-10Presuure（MPaG）

Temperature（℃）

60-20

00

1

2345Time(min)678910Figure 7.2.27.2.2-1 Rapid filling experiment of high pressure filling system(25MpaG)‑56‑

Change of temperature and pressure of tank at 35MPaG
50

100
90

Pressure

Temperature（℃）

703060504020

In-side temperature

30Pressure（MPaG）

4080

102010Out-side wall temperature
000123456Time (min)78910Figure 7.2.27.2.2-2 Rapid filling experiment of high pressure filling system(35MpaG)
7.2.3

Examination of technical guidelines for Hydrogen Refueling Station

With a policy that easing of official restrictions is not our aim, we examined safetyissues closely about two types of the hydrogen refueling stations built in this year,
holding working groups of production, storage and filling. For safety measures
adopted for these hydrogen refueling stations, fundamental philosophy for safety andmounting locations for sensing devices were investigated.
This work was conducted in cooperation with Task 2 taking charge of safety ingeneral of WE-NET Project. Task 2 reviewed safety measures adopted hydrogen
refueling stations to confirm that these hydrogen refueling stations were safely
constructed; design review on July 17 and on-site review for reformer type ofhydrogen station on Oct. 31, water electrolysis type of hydrogen station on Feb. 1.

Itis necessary to know the extent of disaster by explosion in order to secure safety ofhydrogen refueling stations. Task 2 took charge of hydrogen explosion experiment. In
fiscal year of 2001, explosion experiments on (a) semi-open system and (b) ductsystem were carried out.

‑57‑

7.3

Research and Development Subject in the Future(1) Optimization of rapid filling to test tank
1) Metal hydride filling system
・Control of hydrogen filling and brine flowing
・Optimization of rapid filling and sensing full charging

2) High pressure filling system
・Control of hydrogen filling・Optimization of rapid filling and sensing full charging(2) Optimization of total system of hydrogen refueling station and safety estimation
・ Optimization of total system of hydrogen refueling station combining component

equipments
・Verification of basic performance by periodic self inspection
・Legal safety inspection for high pressure equipments(3) Examination of technical guidelines for hydrogen refueling station
・Safety evaluation of component equipments as well as total system
・Clarify the point of improvement on safety
・ Documentation of safety guideline for hydrogen refueling station based on results

obtained from evaluation mentioned above and experiments on hydrogen diffusionand explosion conducted by the Task 2 program‑58‑