Special Issue

Energy and Global Environment for the 21st Century

Reviews

Action for Development of Eco-technology

Tateki MIZUNO(Environmental Assessment Dept., NIRE)

Abstract
If mass-consumption and mass-disposal in developed countries and rapid increase in population of developing countries continue hereafter, global environmental burden and restriction of natural resources or energy might considerably affect the society of human being and global ecological system. In 1992, UNCED appealed that concept of sustainable development should become the principle of the human society in future. It should be importantto try to cleate new technologies for the sustainable development from now . For construction of sustainable society and creation of new environment, NIRE intends to be the pioneer of the technological development with the concept of eco-technology. This is the brief introduction of the eco-technology and its background.

Key words ; sustainable development, ecc-technology

(Language:Japanese)

Reviews

Technological Trends in Coal Energy

Minoru Shiraishi(NIRE, Chief Senior Researcher)

Abstract
Coal is currently an important resource providing 30% of the energy used throughout the world. R & D of clean coal technology (CCT) is being carried out in Japan, USA and EC, making use of future technology that includes coke making, high efficiency coal power generation, coal gasification and liquefaction. The property of caking imparted by rapid coal pyrosis, de-NOx in circulating fluidized bed coal combustion, desulphurization in coal gasification and coal solubilization by using super acid are introduced as related research conducted at this Institute.

Key Words : coal, CCT, R&D, coke-making

(Language:Japanese)

Reviews

Biomass and Bioenergy into the 2lst Century

Ralph P. Overend(National Renewable Energy Laboratory)

Abstract
Bioenergy, the world, s fourth most important energy resource, contributes about 50-55 exajoules (EJ) of primary energy (after petroleum, 119 EJ; coal, 86 EJ; and natural gas, 67 EJ). Industrial counties use biomass indirectly in industry, agriculture, forestry, and power generation at reasonable process efficiency. Conversely, two billion (2 x 10⁹) people in developing countries use biomass directly, as a solid fuel for their daily needs such as cooking, and do so at low efficiency and often to the detriment of the environment. As incomes rise in developing countries, the trend is away from biomass towards purchased fuels that are efficient, clean, and convenient. However, such a trend replaces a renewable, carbon-neutral energy source by fossil fuels that have the potential to raise global greenhouse-gas emissions by 10%. The challenge, therefore, is to fund technologies that fit a social model of development that will facilitate the high-efficiency use of biomass as Bioenergy while reducing the environmental risks of biomass use and avoiding growth in fossil-fuel use.

The future Bioenergy System must be predicated on sustainable biomass feedstocks supplied by agriculture and forestry, coupled with the management of biomass-derived material flows in society. The biomass must then undergo efficient transformation into clean secondary energy forms that are compatible with the much larger equipment and facilities base now provided by commercial fossil fuels.

Significant components of the future system are already developed or are being demonstrated. In most developing countries agricultural yields are rising, thus providing both more foodstuffs and more crop residues that may be used for Bioenergy purposes. In parallel, the scale of food-processing mills and livestock operations is increasing, all of which increase the economic potential of converting biomass into compatible and efficient secondary energy forms such as methane, low- and medium-calorific-value gases, and electricity. Efficient technology to do this is being developed and applied worldwide.

Key Words : Biomass, baiofuel, Bioenergy, Renewable energy, Conversion technology, future energy scenario

(Language:English)

Reviews>

Methane hydrate : Undeveloped clean energy resource

Michio KURIYAGAWA(EDeputy Director-General., NIRE)

Abstract
Methane which is the major constituent of natural gas is known as clean energy, because the amount of carbon dioxide discharged to produce a unit amount of energy is low. The rate of natural gas to the total amount of primary energy supply was about 10.8% in 1994 compared to 0.9% in 1991. As Japan produces only about 5% of its natural gas needs, methane hydrate, which is a solid substance like sherbet under high pressure and low temperature and exists under the ocean moor around Japan, is expected to be a major domestic energy resource.

In our Institute, NIRE, fundamental studies have begun to extract methane kom methane hydrate with high efficiency, less cost and least environmental damage. In this paper, major parts of the research activities in our Institute are introduced.

Key words : Methane hydrate, clean energy, natural gas

(Language:Japanese)

Reviews

The Status of Energy and the Environment in Korea

Young-Mok Son(President of KIER)

Introduction
With the economic development drives embarked on in 1960s, economy in Korea has maintained the high growth rate of over 5% since 1980s. Along with this growth, the demands for the energy have constantly been on the rise, increasing the energy importation due to lack of domestic energy resources. Also, the increase of energy consumption resulted in the increase in pollutants emission, worsening the environmental pollution.

Estccia11y in this situation where global environment protection, as shown in the Convention on Climate Change, is a hot issue world-wide, the government is proposing various energy- and environment-related policies for the goal of continuous economic advancement and improved environment. This paper will briefly discuss characteristics of energy demand and supply in Korea, ongoing rn11ution, plans for development of energy technologies and measures to prevent environmental pollution.

Key Words : Emission control, Volatile chlorinated hydrocarbons, Branched cyclodextrins

(Language:English)

Reviews

Energy and Environmental Response Technologies Using Solar Energy (Light) in the Future

Takashi IBUSUKI(Atmospheric Environmental Protection Dept., NIRE )

Abstract
Utilization of huge amount of solar energy can significantly contribute to the solution of both energy and global environmental issues. Research and development of technologies which can utilize solar light in different ways are reviewed as follows ; 1) Production of electricity by photovoltaic cell 2) Production of biomass and others by photosynthetic ability of green plants, algae and others, 3) Chemical conversion of CO₂ and/or water to energy substances like hydrogen, methane or others by photocatalysts, 4) Decomposition and/or treatment of environmental pollutants through photocatalysis.

Key words : Utilization of solar energy (light), Photovoltaic cell, Biological methods, Chemical methods, Purification of environment

(Language:Japanese)

Original Paper

Reduction and Removal of selenate ion by TiO₂ photo-catalyst

Eiji KIKUCHI (Mineral Processing Div., Materials Processing Dept., NIRE)
Sinichi ITOU (Mineral Processing Div., Materials Processing Dept., NIRE)
Mikio KOBAYASI (Rare Metals Div., Materials Processing Dept., NIRE)
Hirosi SAKAMOTO (Materials Processing Dept., NIRE)

Abstract
Selenate ion in aqueous solution can be reduced to hydrogen selenide by using TiO₂ photocatalyst in the presence of organic reductant.

The experiments were carried out by using sodium selenate solution as model waste water whose concentration is 100 ppm selenium. Organic reductant, acid and 0.10 - 0.11 g of TiO₂ powder were added to 100 ml of this model waste water. The total selenium concentration became 0.02 - 0.04 ppm with 1 hour irradiation, when 2.5 mmol of formic acid is added. In this case, it was found that selenium in the model waste water was reduced to hydrogen selenide and removed from the solution.

Key words : Photoelectrochemistry, TiO₂, Photocatalyst, Selenium, Selenate

(Language:Japanese)