Special Issue

NIRE's Technological Approach to Global Warming Control

Review

Research and Development on Mitigation Technology against Global Warming by NIRE to Support New Earth 21 Program

Shin-ya YOKOYAMA (Global Warming Control Department NIRE)

Abstract
NIRE (National Institute for Resources and Environment) has been doing research and development to counter global warming and support the New Earth 21 Program. In this report, the present status and future scope of several research projects including GLAD system, methanol synthesis by hydrogenation of carbon dioxide, artificial photosynthesis, biomass energy plantation, and LCA are briefly reviewed and the desired requirements are mentioned to fulfill the mitigation technology to deal with global warming.

Key words : Carbon dioxide,Global warming,GLAD,Methanol,Photosynthesis,Biomass,LCA

(Language:Japanese)

Review

Methanol Synthesis via Hydrogenation of CO₂

- Advancement of Joint Research between RITE and NIRE -

Masahiro SAITO (Chemical Process Division ,Global Warming Control Department NIRE)
Taiki WATANABE (Catalysis Lab.,Project Center for Chemical CO₂ Fixation and Utilization)

Abstract
The advancement of the joint research between RITE and NIRE on methanol synthesis via catalytic hydrogenation of CO₂, which was started in December, 1990, is reperted briefly.

High performance Cu/ZnO-based multicomponent catalysts were developed on the basis of the role of metal oxides contained in Cu/ZnO-based ternary catalysts.

Sn the following step, practical methanol synthesis operations were investigated using a recycle reactor equipped with a compressor for recycling unreacted gases.

A bench plant with a capacity of 50kg-CH₃OH/day was constructed in April, 1996. At present stage, practical tests are being performed using the bench-scale plant..

Key words : CO₂,Hydrogenation,Methanol Synthesis

(Language:Japanese)

Review

Highly Efficient Sequestration of CO₂ at Sea

Takayuki SAITO (Mining and Geotechnology Department, Ocean Mechanics Division, NIRE)

Abstract
We have developed the GLAD (Gas Lift Advanced Dissolution) system to mitigate the effects of global warming. It is a newly developed system for disposing of CO₂ at sea by means of a gas-lift pump and has an inverse-J pipeline set in the sea at a depth of 200-3000m. First, merits and demerits of previous methods, such as deep-sea sequestration of liquid CO₂, are summarized. On the basis of the summary, a method to overcome the demerits will be discussed. Second, principal, experimental results and numerical results on the GLAD are discussed. Third, cost estimate and feasibility analysis of the GLAD will be considered.

Key words : Carbon dioxide,Ocean disposal, Gas-Lift, Mulitiphase turbulent flow, bubby flow, mass transfer

(Language:Japanese)

Integrated paper

Photochemical Reduction of CO₂ Using Rhenium Complexes

Hisao HORI (Global Warming Control Department, Photo Energy Application Division, NIRE)
Kazuhide KOIKE (Global Warming Control Department, Photo Energy Application Division, NIRE)
Osamu ISHITANI (Saitama University)
Koji TAKEUCHI (Global Warming Control Department, Photo Energy Application Division, NIRE)
Takashi IBUSUKI (Atmospheric Environmental Protection Department, NIRE)

Abstract
A series of rhenium complexes : fac-Re(bpy)(CO)₃L⁺ [bpy=2,2'-bipyridine, L=P(n-Bu)₃, PEt₃, PPh₃, P(OMe)Ph₂, P(Oi-Pr)₃. P(OMe)₃, P(OPh₃)] was prepared and characterized by IR, UV-VIS, NMR, and CV. The CO₂ photocatalytic reduction by these complexes was also studied.

Variations in the spectroscopic properties of fac-Re(bpy)(CO)₃L⁺, i.e., CO stretching, MLCT (metal to ligand charge transfer) energy, emission parameters (quantum yield, lifetime), and ³¹P-NMR chemical shifts were interpreted on the basis of the electron-acceptor strength of L. However, the redox potential of Re(bpy)(CO)₃L⁺/Re(bpy^-)(CO)₃L (E_1/2), did not follow the order of the electron-acceptor strength of L. The moderate electron-acceptor strength of L resulted in more negative E_1/2.

Irradiation of a DMF-triethanolamine (TEOA) solution of the complex saturated with CO₂ gave CO catalytically. The quantum yields of CO formation () varied with L. Thevalues complicatedly depends on the electron-acceptor strength of L, i.e., moderate electron-acceptor strength of L gives rise to high . In-situ UV-VIS spectra during the photocatalytic reaction showed that the one-electron reduced species Re(bpy^-)(CO)₃L was produced with high yields of 20-100%.

The mechanism of CO₂-fixation by fac-Re(bpy)(CO)₃PPh₃⁺ was examined by HPLC and electrospray mass spectrometry. It was revealed that initial complex rapidly changed (quantum yield : 16.9) to solvent complexes fac-Re(bpy)(CO)₃(TEOA)⁺ and fac-Re(bpy)(CO)₃(DMF)⁺ via one-electron reduction, and then they changed to a formate complex Re(bpy)(CO)₃OCHO. The rapid ligand exchange reaction with solvent molecules was interpreted by a chain reaction mechanism.

Key words : Rhenium complex, Photocatalyst, CO₂ reduction

(Language:Japanese)

Original Paper

Technology Assessment of Alternative Fuels by CO₂ Fixation Use in Passenger Cars

Seiji MATSUMOTO (Thermal Energy Applications Div.,Thermal Energy and Combustion Engineering Dept., NIRE)
Atsushi INABA (Fundamental Research Div., Energy Resources Dept., NIRE)
Yukio YANAGISAWA (Dept. of Chemical System Engineering, Faculty of Engineering, The University of Tokyo)

Abstract
Alternative fuel vehicles were investigated as a possible mitigation measure to reduce CO₂ emissions. Fuel economies of several alternative cars were compared, and integrated CO₂ emission from fuel mining to consumption in Japan were calculated. The alternative fuel vehicles we investigated were methanol, compressed natural gas, electric and hydrogen.

Our calculation showed that a combined approach discharged the least amount of CO₂ when compared to individual alternative fuel vehicles studied in this paper. The combined approach was to use methanol and electricity coming from a coal-fired power plant. Methanol was produced from CO₂ collected from the flue gas of a coal-fired power plant and hydrogen originated from a non-carbon natural energy source. The methanol-fuelde vehicle emitted 28.4 kg-CO₂ per 100km-driven. Electricity generated at the coal-fired power station could be supplied to the electric vehicles. The CO₂ emission per 100km driven was reduced to 15.0 kg by the combination of the methanol and electric vehicles.

Key words : CO₂ , Mitigation measure, Alternative fuel vehicles, Methanol, CO₂ recycling

(Language:Japanese)

Original Paper

The development of a software to calculate CO₂ emission in Japan

Mitsuo KOBAYASHI (Energy Resources Dept., Fundamental Research Div., NIRE)
Atsushi INABA (Energy Resources Dept., Fundamental Research Div., NIRE)
Yasuhiko KONDO (Energy Resources Dept., Fundamental Research Div., NIRE)
Hiroshi YAGITA (RITE)
Seiji MATSUMOTO (Thermal Energy and Combustion Engineering Dept., Thermal Energy Applications Div., NIRE)
Masakazu YAMAZAKI (Thermal Energy and Combustion Engineering Dept., Thermal Energy Applications Div., NIRE)
Hiroaki KONDO (Environmental Assessment Dept., Atmospheric Environment Div., NIRE)
Hitoshi OHYA (Materials Processing Dept., Materials Handling and Characterization Div., NIRE)
Akihiko OHI (Atmospheric Environmental Protection Dept., Air Quality Measurement Div., NIRE)
Tsutomu YAMAGUCHI (Mining and Geotechnology Dept., Geomechanics Div., NIRE)
Masayuki SAGISAKA (Safety Engineering Dept., System safety Div., NIRE)
Koichi MIZUNO (Research Planning office, NIRE)
Nonuo KIDO (General Research Counselor, NIRE)

Abstract
A software "NICE (NIRE CO₂ Emission Model)" was developed to analyze CO₂ emissions in Japan through at the year of 2050. The CO₂ emissions in the future was calculated on NICE based on the fossil fuel consumption derived from the energy demand and supply structure constructed by the scenario which was fixed by the selection of values for 19 parameters, related to energy demand including the increase of GDP and population and the improvement of energy efficiency for industry, residence and volume of traffic, and to energy supply such as the development of renewable energy technologies and the transformation of electricity resources.

"NICE" runs under Windows 95 on a standard PC platform. As the total CO₂ emission in Japan and the CO₂ emission of each sector, industry, transportation and residence, are illustrated as a result of the selection of economical and technological parameters, it should be a powerful tool to understand the relationship between each parameter and CO₂ emission.

Key words : CO₂ Emission Model, Software of CO₂ Emission

(Language:Japanese)

Original Paper

Dehydrogenation of Ethylbenzene in the Presence of Carbon dioxide as a New Energy-Saving Process

Naoki MIMURA and MasahiroSAITO (Global Warming Control Department, Chemical Process Division, NIRE)

Abstract
Thermodynamic determination of dehydrogenation of ethylbenzene in the presence of steam or CO₂ clearly indicates that the yield of styrene in the presence of CO₂ is much more higher than that in the presence of steam. The two-step pathway appears to be better for yielding styrene at equilibrium at a given temperature.

The amount of energy required for the new process using CO₂ is much lower than that for the present process, mainly due to fact that a large amount of latent heat of steam condensation cannot be recovered during commercial processing using steam. Consequently, dehydrogenation in the presence of CO₂ should be an energy-saving process.

Key words : Carbon dioxide, Ethylbenzene, Styrene, Dehydrogenation, Energy saving

(Language:Japanese)

Technical Report

Environmental Chamber for studying stratospheric chemistry

Shuzo KUTUNA and Koji TAKEUCHI (Global Warming Control Department, Photo Energy Application Division, NIRE)

Abstract
We have constructed an environmental chamber for studying stratospheric chemistry. It is capable of controlling the temperature down to 233K, together with an illumination system with a wavelength between 170 and 800 nm, a sub-reactor with a gate valve for studying heterogeneous chemistry, and IR measurements with high resolution (0.0026cm^-1). It can also be used to study atmospheric chemistries of thermally unstable compounds as dinitrogen pentoxide (N₂O₅), the kinetics and mechanisms of gas-phase reactions of new compounds and their atmospheric degradation products, IR and/or VIS-UV spectra of them, and catalytic reactions for environmental improvement in purification.

Key words :Environmental Chamber, Stratospheric chemistry, High resolution IR measurement, Heterogeneous process

(Language:Japanese)

Technical Report

Research for the energy supply potential of woody biomass

Yutaka DOTE (Miyazaki University)
Tomoko OGI (Global Warming Control Department, Biomass Division, NIRE)

Abstract
Biomass energy is considered as one of the most favourable options for reducing CO₂ emission and preventing climatic changes. Land area estimated for biomass energy plantation ranged quite widely from 60-2,000Mha, depending on various factors. We estimated the biomass energy supply and plantation area based on the FAO data, considering the competition of biomass supply with and without food supply at year the 2100. The estimation showed that more than 300 EJ/y, proposed value in IPCC Report, could be supplied only in the case of higher biomass productivity. Considering the competition of biomass supply with food supply, the biomass energy supply decreased by 16% compared to that without the competition. U. S. A and the former USSR,which are the largest CO₂ emitting countries, had a high potential for biomass energy.

Key words :Biomass energy supply, plantation area, Competitionwith food supply

(Language:Japanese)