WE-NET Home Page/Summary of Annual Reports 1997

Summary

1. Objective of R&D

International Clean Energy Network Using Hydrogen Conversion (WE-NET) aims at contribution to solving global environmental problems by means of large-scale and effective utilization of clean and renewable energies such as hydraulic, solar, and wind which are available widely on the earth. Its purpose is also to establish technologies capable of introducing an international energy network utilized in wide fields such as hydrogen production from these energies, conversion of hydrogen as necessary, transportation, storage, generation of power, fuel for transportation, and town gas, in order to satisfy energy demands, and to develop core elementary technology as well as preparation conceptual design of the total system.

Phase I of WE-NET scheduled for six years from FY 1993 aims at establishment of basic technologies for hydrogen production, hydrogen transportation and storage, and utilization of hydrogen, by means of necessary investigation, basic researches, and studies for elementary technologies, in order to obtain information necessary for the optimum design of the total system and establish technologies necessary for the design and construction of a pilot plant. In addition, studies for technologies adaptable to the project in future are intended to be carried out in parallel with the above to be properly reflected on every research and development items.

The results obtained in R&D of Phase I will be reflected on realization of the plans of Phase II. Fig 1 shows the schematic illustration of WE-NET.

2. Items and targets of R&D

R&D for Phase I is divided into the following nine subtasks. Targets for each subtask are as follows.

2.1 Subtask 1: Investigation and study for evaluating and reviewing R&D

Regarding each individual technology development constituting systems such as hydrogen utilization technologies including hydrogen production, hydrogen transportation and storage, and hydrogen-combustion turbines of WE-NET, studies are to be implemented for the constant overall coordination of the project, the overall evaluation of developed results, and the optimization of development schedule.

In addition, tendencies of internal and external technology development are to be studied to reflect them upon the future work of the project programs.

2.2 Subtask 2: Review and investigation for promoting international cooperation

In order to establish a worldwide system, periodic information exchanges are performed with international organizations and relating countries, while the progressing procedures and measures are to be studied for developing the project as an international joint research.

2.3 Subtask 3: Conceptual design of the total system

Development of a conceptual design of the total system consisting of such facilities as power generation using renewable energy, hydrogen production, transportation medium production, storage, transportation, and utilization is to be conducted to make the technological and economical evaluation. The effect of the introduction of hydrogen energy is to be estimated in a world-wide level and individual country level. Development of safety measures and evaluation technologies is to be conducted from the perspective of the total WE-NET system.

2.4 Subtask 4: Development of hydrogen production technology

In hydrogen production methods by water electrolysis, there are the alkali water electrolysis which has been commercialized, solid polymer electrolyte water electrolysis which is promising in future, and high temperature steam electrolysis which is a step verifying its principle. Among these methods, in Phase I, the investigation necessary for achievement large scaling-up and long life is to be carried out for the solid polymer electrolyte water electrolysis which is expected in high efficiency and high current density. Therefore, technologies necessary for a bench scale plant are to be established by development of elementary factors such as solid polymer electrolyte (ion exchange membrane), anode and cathode catalysts, and materials for elertrolyzer, and implementation of bench scale tests.

2.5 Subtask 5: Development of hydrogen transportation and storage technologies

Liquid hydrogen, hydrogen gas, ammonia, methanol, and cyclohexane have been considered as media for hydrogen transportation. Among them, mass transportation and storage for liquid hydrogen has not yet been started to be developed both internally and externally. However, liquid hydrogen is to be adopted as an object of this R&D for an approach promising in the near future, from the perspective of higher efficiency for transportation, simple conversion, and convenience in using at consuming areas, as the result of a careful study because this is an important developing theme.

However, the other hydrogen transporting media are to be studied in the conceptual design of the total system in Subtask 3, taking the states of R&D and realization into consideration.

Accordingly, necessary investigations, basic researches, and elementary technology development are to be conducted for the following items regarding the hydrogen production, transportation, and storage, in order to obtain findings necessary to determine an optimum system for mass transportation and small-scale storage and small-scale transportation.

(1) Development of large-capacity hydrogen liquefaction facilities
(2) Development of liquid hydrogen transportation tanker
(3) Development of liquid hydrogen storage facilities
(4) Development of devices for common use
(5) Development of hydrogen absorbing alloys for small-scale transporting and storage system

2.6 Subtask 6: Development of cryogenic materials technology

Although the existing materials useable in the cryogenic range (20K) are available in certain cases at present, there is few data regarding toughness, fatigue, and serration of structural materials at the temperature range of liquid hydrogen. In addition, since structural materials used in the liquid hydrogen environment may contact gas hydrogen at room temperature, they must have the strong property against hydrogen embrittlement. On the other hand, materials useable in the liquid hydrogen range are hard to be welded, and problems of cracks in welded parts are caused if welding is made. Therefore, structural materials useable in the liquid hydrogen condition and their proper welding methods are to be studied, by development of new materials as necessary as well as obtaining of basic data for the existing materials. The requirements from materials are to be determined relating to the development of hydrogen transportation and storage describing in Subtask 5.

2.7 Subtask 7: Feasibility study on utilization of hydrogen energy

Investigation, studies, and proposals of applicable technologies are to be conducted concerning the utilizing technologies and demand of hydrogen in future in various fields, such as power generation, industry, transportation, and civil application, in various methods of using hydrogen gas, liquid hydrogen, and methanol, so that the merits and demerits of each technologies are to be clarified and the themes to be developed in hydrogen utilizing technologies are to be selected. In addition, investigation concerning technology utilizing cryogenic energy of liquid hydrogen is to be studied to evaluate the application technologies.

Development of elementary technology for each hydrogen utilizing technologies is to be conducted as necessary.

2.8 Subtask 8: Development of a hydrogen-combustion turbine

The required investigation and development of elementary technologies for the following items are to be studied for hydrogen combustion turbines which are expected because of their extraordinary high efficiency as a hydrogen utilizing technology, and technologies necessary for development of a pilot plant is to be established.

(2) Development of the combustion control technology
(3) Development of turbine-blades, rotor and other major components
(4) Development of major auxiliary equipment
(5) Development of super-pyrogenic materials

2.9 Subtask 9: Study of innovative and leading technology

WE-NET is a long-term project. Therefore, in promoting the project, there may be some certain innovative and leading technologies not included in present objects of R&D, although they are promising for the future. On the other hand, incorporation of existing technologies into WE-NET project may be necessary depending upon their technological improvements.

Such innovative and leading technologies and existing technologies are to be studied, investigated, and evaluated, and as necessary the minimum elementary researches are to be conducted to reflect obtained promising technologies on WE-NET project.

The development schedule of R&D items mentioned above is shown in Table 1.

3. Summary of FY 1997

In FY 1997, existing and elementary technologies were investigated for each research and development items. Major results are summarized below.

Subtask 3-2 "Study on a global network" and Subtask 8-1 "Study on an optimum system for hydrogen-combustion turbines", for which expected results have been obtained by carrying out the relevant process, were finished in FY 1996.

3.1 Subtask 1: Investigation and study for evaluating and reviewing R&D

The WE-NET project was comprehensively evaluated, the tasks were all coordinated, and the overall plan for Phase II of the project was reviewed.

3.2 Subtask 2: Review and investigation for promoting international cooperation

(1) Research cooperation with overseas institutes was initiated to exchange technologies and information.<

(2) Preparations were made to open a WE-NET home page (in English and Japanese).

3.3 Subtask 3: Conceptual design of the total system

(1) With respect to a system comprising all stages from production to utilization of hydrogen, basic data on alternative hydrogen production middle range hydrogen gas transmission pipelines, and distributed utilization was examined and compared with such data for a transportation and storage system using liquid hydrogen, methanol, or ammonia.

(2) Existing simulation models were modified and coordinated to evaluate the effects of introducing hydrogen energy at national and city levels.

(3) The modification both the simulation models for hydrogen dispersion and hydrogen explosion-fire has been tried. The second mini-workshop on hydrogen safty was held in USA. The experts from overseas and Japan have exchanged opinions and discussed on safty topics

3.4 Subtask 4: Development of hydrogen production technology

Based on the two methods of electroless plating and hot pressing, which were selected in FY 1996, water electrolysis was continued for 3,500 hours using laboratory cell with electrode area of 50 cm2. As a result, it was confirmed that energy efficiency was stable at 90%. Furthermore, a single cell with electrode area of 2,500 cm2 was produced for experiments in which an energy efficiency of 90% was achieved at 80℃ and 1A/cm2.

Several types of high temperature solid-polymer electrolytes were synthesized. Proton conductivity was 0.52 S/cm at 200℃. FIG. 2 shows the results of durability tests using solid-polymer electrolyte water electrolysis.

3.5 Subtask 5: Development of hydrogen transportation and storage technologies

(1) Development of large-capacity hydrogen liquefaction facilities
The two liquefaction cycles, which were selected in FY 1997 were evaluated.The Hydrogen Claude Cycle was selected as the optimum liquefaction cycle for the large hydrogen liquefaction facility.

(2) Development of liquid hydrogen transportation tanker
The test pieces of thermal insulation elemental experiment for the liquid hydrogen transportation tanker were designed in order to examine the problems of the entire thermal insulation structural system and the solutions to these problems.

(3) Development of liquid hydrogen storage facilities
In order to conduct thermal insulation tests and thermal insulating structure strength tests, the test apparatuses were produced and the pieces were designed.

(4) Development of devices for common use
Magnetic floating bearing unit tests were conducted in a liquid hydrogen atmosphere as elementary tests for large liquid hydrogen pumps to confirm the appropriateness of the design and to identify problems.

(5) Development of hydrogen absorbing alloys for small-scall transportation and storage system

With respect to magnesium-based alloys potentially having a high hydrogen absorbing performance, the improvement of the hydrogen absorbing characterisic by amorphism and nanocrystallization and the development of a new ternary system hydrogen absorbing alloy having a new crystal structure were proceeded.

3.6 Subtask 6: Development of cryogenic materials technology

With respect to stainless steels SUS304L and SUS316L and aluminum alloy A5083, which are among the typical existing structural materials, material charactoristics such as the tensile strength of a base material and that of a welded portion were tested and evaluated using a new testing facilities in a liquid hydrogen environment. In addition, the behavior of hydrogen during in filtration into the material was studied, and a database for the cryogenic materials was compiled.

3.7 Subtask 7: Feasibility study on utilization of hydrogen energy

(1) In the field of cogeneration, study was focused on cogeneration with a hydrogen diesel engine to investigate relevant systems and each elementary technology for a hydrogen injection or ignition system. In addition, to check the applicability of each elementary technology to the system, combustion test equipment was produced and preliminary data acquisition was started.

(2) In the fields of transportation (vehicle) and hydrogen refueling systems (refueling stations), domestic and overseas R&D trends were studied and specifications for hydrogen vehicle and refueling stations were reviewed. FIG. 3 shows examples of a hydrogen vehicle and a hydrogen refueling station that are experimentally used overseas.

(3) In the field of fuel cells (PEFC) and utilization of cryogenic energy applcation, elementary technologies were investigated, including polymer electrolyte fuel cells using a pure-hydrogen fuel and manufacturing of oxygen using low temprature air separation process.

3.8 Subtask 8: Development of a hydrogen-combustion turbine

(1) Development of combustion control technology
The detailed design and production of a combustor used for evaluation tests scheduled for FY 1998 were completed, and preliminary combustion tests were conducted under atmospheric conditions to confirm the basic performance specifications. In addition, the detailed aspects of the evaluation tests such as test conditions and methods were reviewed, and test facilities were produced, experimentally operated, and adjusted. FIG. 4 shows the overall view of the combustor evaluation test apparatus.

(2) Development of turbine-blades, rotors, and other major components
The detailed design and production of test blades used for cooling-blades evaluation tests scheduled for FY 1998 were completed, the basic outline of the tests was established, and the trial design and partial production of an evaluation test apparatus were implemented. In addition, a facility for testing the inner and outer surfaces of blades to determine their heat transfer characteristics (elementary tests) was designed, constructed, and partially tested.

(3) Development of major auxiliary equipment
After the optimum system was selected in FY 1996, heat transfer pipes for high-temperature heat exchangers were optimized, the strengths of tube panels and casings were studied, and conceptual desigh of high-temperature heat exchangers were conducted. Technical evaluation items scheduled for FY 1996 were also investigated. The other points reviewed were the conceptual design of a system for utilizing the cryogenic energy of liquid hydrogen including oxygen production equipment, and the specifications of major components.

(4) Development of super-pyrogenic materials
With respect to heat-insulating alloys, ceramic matrix composites, and C/C composites that are expected to be used for parts of hydrogen-combustion turbines, materials were designed, experimentally produced, and their basic properties (physical, chemical, and dynamical properties) were tested and evaluated.

3.9 Subtask 9: Study of innovative and leading technologies

Proposed innovative and leading technologies were evaluated and conceptually examined.

4. Future Development

Research and investigation will be continued and elementary technologies will be developed to complete the optimum design of the total system and to establish major elementary technologies. R&D plan of Phase II, which will start in FY 2000, will also be clarified.

The "Draft of proceeding of WE-NET program Phase II", which has been jointly prepared by NEDO and the Institute of Applied Energy; WE-NET Center, is appended at the end of this report as a reference.