After COP3 a lot of countries and even their local governments are struggling to reduce CO2 emissions. However, the way to define CO2 emissions is not consistently standardized. In this study we calculate CO2 emissions in two ways: appar-ent and responsible emissions. Apparent CO2 emissions are caused by the domestic industrial activities and they include CO2 embodied in exports. Responsible CO2 emis- sions are attributed to domestic final demand and they include CO2 embodied in imports. We classify domestic production into that of Tokyo and that of the other regions, and cal-culate regional CO2 emissions by the above two ways. From the viewpoint of LCA (Life-Cycle Assessment), we utilized the regional input-output table for the database. Apparent and Responsible CO2 emissions of Tokyo are 17 Mt-C and 32Mt-C, respectively. Because the amount of CO2 results in such different values, standardizing the way to define CO2 emissions is a critical problem for deciding the goal of CO2 reduction. Concerning the emissions in each sector, power generation and transport have the largest reduction potential in industrial sectors. Making the life of buildings longer is the most effective measures from the consumers' viewpoint.
CO2 and NOx emissions per unit amount of basic materials and sec-ondary energy products were analyzed, by taking following two factors into account. The first is the influence by imported raw materials, and the second is that from alloca- tion rule. CO2 emission from mining and transportation of fossil fuels accounts for a few percents to a quarter of direct emission by combustion. International marine transport of fossil fuels and metal ores largely contributes to life cycle NOx emission, because of the very high emission factor of NOx per unit amount of energy consumption by diesel engine of vessels. Allocation of environmental burdens by calorific unit and by mone-tary unit was discussed, using the following two examples; burdens associated with sup-ply of crude oil and their refinery to secondary petroleum products; energy cascading of blast furnace gas. A case study on the average automobiles revealed that burdens asso-ciated with imported resources are significant compared to domestic emissions in their production stage and use stage, and allocation rule may also give large influence upon their life cycle inventory.
Primary aluminum consumes much energy in its production process-es leading a great quantity of emissions. In Japan, 99 ‰ amount of primary aluminum is currently imported from other countries. In this work, Global Warming Potential (GWP) and Acidification Potential (AP) values for primary aluminum ingot produced in Brasilia, Russia, Australia, Venezuela, U. S. A., Norway and Island have been investigated. The average GWP and AP values for Japanese import mixtures were calculated. The mini-mum GWP and AP values for primary aluminum ingot produced with best available tech-nology have also been estimated. It was found that GWP value of primary aluminum ingot produced in each country varied from 10.4 to 27.4 kg-CO2 equiv./kg, while AP value varied from 0.0172 to 0.135 kg-SO2 equiv./kg. The average GWP and AP values for Japanese import mixtures were 15.5 kg-CO2 equiv./kg and 0.0516 kg-SO2 equiv./kg, respectively. GWP value of primary alu-minum ingot could be reduced up to 6.32 kg-CO2 equiv./kg if it is produced with best available technology, and AP value could be reduced up to 0.0103 kg-SO2 equiv./kg. The environmental impact of primary aluminum ingot widely varies according to which coun-tries primary aluminum ingot was produced in and which technology was used in its pro-duction process.
One of the most important themes to promote Eco-design is the uti-lization of recycled materials. But little is known about the environmental information on total impacts from production of recycled materials in Japan. In recent years, many studies concerning the methodologies of impact assessment have discussed to show one single index about total environmental impacts. The ques-tion of how to include “resource depletion” as a safeguard subject is still open. We have suggested a methodology that provides us a total indicator based on Japanese environ-mental problems and resource consumption. In this paper a research program for investigating the environmental impacts of pro-duction metals in Japan is described. Moreover, the differences of environmental impacts between primary metals and secondary metals were discussed as a case study.
100 samples of recycle solvent were obtained from continuous opera-tion (50 days) of 1 ton/day coal liquefaction plant at Kimitsu. Pyrene and fluoranthene derivatives in the recycle solvents were anslyzed in detail by the technique of selective ion measurement of GC/MS. According to the replacement of the initial solvent by coal-liquid solvent, the sum yields of pyrene and fluoranthene derivatives decreased: the yields of pyrene derivatives and fluoranthene derivatives in the recycle solvents after 50 days operation was ca. 1/2 and 1/10 of those in the initial solvent, respectively. Principal reactions of pyrene, methylpyrenes, and fluoranthene in the solvent hydro-genation process were hydrogenation to hexahydropyrenes, to dihydromethylpyrenes, and to tetrahydro-and decahydrofluoranthenes, respectively. In order to controle the hydrogenation of recycle solvent during hydrotreating step, the relative amount of pyrene and hexahydropyrene in the recycle solvent was considered to be a suitable indi-cator.
An integrated coal gasification molten carbonate fuel cells power generation system (IG-MCFC) has higher thermal efficiency than an integrated coal gasi-fication combined cycle power generation system (IGCC). In IG-MCFC, it is necessary to remove sulfur compounds (H2S, COS) so that there are less than 1 ppm. Iron oxide sorbents developed in IGCC can not achieve this. New sorbents need to be developed for this reason. A zinc element has high ability for sulfur removal to less than 1 ppm. We prepared mixed oxide sorbents containing iron and zinc, and evaluated the characteristics of H2S removal. 1. A zinc element, which was added to the sorbents as zinc ferrite (ZnFe204), had the highest reactivity. 2. Silica added to zinc ferrite had much effect on protecting of carbon depositions. 3. Zinc ferrite sorbents could remove H2S down to less than 1 ppm. 4. Zinc ferrite sorbents after regeneration couldalso have less than 1 ppm. 5. The sorbents' desulfurization performance after regeneration was influenced by change of the specific surface area caused by regeneration.
The noncatalytic oligosaccharification of microcrystaline cellulose powder in hot-compressed-water (HCW) heated to 200-300°C under 9.8MPa was investi-gated using a HCW flow type reactor. Cellulose was solubilized to water by flowing the HCW at temperatures above 220°C, and the formed water solubles were abundant in oligosacchalides. Although the formation rate of water solubles was increased with increasing temperature of HCW, the formed oligosaccharides were rapidly decomposed to hexose and others when the temperature of HCW exceeded 270°C, the softening tem-perature of the used cellulose. It showed that oligosaccharides could be produced from cellulose in high yield and high rate by flowing the HCW at around 260°C, near under the softening temperature of the cellulose. The enzymatic hydrolysis of the water solubles from cellulose treated with HCW of 260°C was carried out. The water solubles were found to be quickly converted to hexose since water-soluble oligosaccharides can be contacted with the enzyme effectively.