In life cycle impact assessment, the potential impact that a product or service may cause during its life cycle is evaluated. In local impact categories, such as eutrophication, photo-oxidant formation and human toxicity, the potential impact depends on the site and concentration of the substances. The contribution ratios of stationary and mobile sources to the concentration of a substance on surface significantly differ. Thus, it has been pointed out that site- and source-type-specific consideration is necessary in order to obtain meaningful results in impact assessment for local impact categories.In this work, development of site- and source-type-specific life cycle impact assessment methodology for local impact categories in Japan has been carried out. We focused on 9 substances: non-methane hydrocarbons for photo-oxidant formation; SOx, NOx, CO and SPM for human toxicity; and COD, T-P and T-N for eutrophication. Each substance was directly weighted by the distance-to-target method with normalization values and weighting factors defined separately for each site. The weighting factor for each substance was derived from the extent to which the annual average concentration of each substance deviates from the authorized standards. Population ratio in each site to the total population in Japan was alsoreflected in the weighting factor. A sourcetype- specific impact assessment methodology was proposed, in which the contribution ratios of stationary and mobile sources to the concentration of a substance on surface were considered in inventory analyses and normalization values.
Life cycle assessment (LCA) has received much attention as an effective tool to evaluate the environmental burden of a product or service during its life cycle. Many LCA case studies have been carried out in Japan. However, impact assessment has been seldom conducted. Some of the reasons are that impact assessment has not been well investigated and few weighting methodologies practicable for Japan have so far been developed. In this work, development of life cycle impact assessment weighting methodology for Japan basedon the distance-to-target principle has been carried out. The methodology hastransparent characteristics and basically follows the SETAC ‘Code of Practice’: classification, characterization, normalization and weighting. Normalization values were estimated for 6 impact categories. Weighting factors for global warming and depletion of stratospheric ozone were derived from the deviation of annual emissions from authorized targets. In local impact categories, classification and characterization are not carried out; each substanceis weighted directly with the local normalization value and weighting factor. Site-specific differences in indicator points were shown, based on calculations using life cycle inventories for electricity distributed by the electric power companies in Japan.
A life cycle inventory analysis for CO2 emission from steel products in Japan, based on statistics in 1995 was carried out under the system boundary at the ports of resources and materials exporting to Japan. And we assumed that iron scrap doesn't have the energy and environmental factors. The analytical results show that the CO2 emission from electric arc furnace route is amounted to about 28 % of that from integrated steel route due to the scrap treatment on LCA. Although a large amount of ferroalloys are consumed and imported for the production of stainless cold coils, the CO2 emission from the production of ferroalloys in foreign countries was excluded in this study. The calculated result from assuming the same CO2 emissions for the production of ferroalloys in the foreign countries as in Japan, shows that the CO2 emissions in the foreign countries are 32 % and 45 % from integrated steel route and from electric arc furnace route, respectively for the production of stainless cold coil. It is also shown that the CO2 emission in foreign countries for the production of carbon steel coils is little because a small amount of ferroalloy is consumed.
Since most industrial products consume electricity during their life cycle, the results of inventory analyses are usually sensitive to the data of electricity. In Japan, electricity is supplied by 10 electric companies that have their own regions to supply electricity. Constitution of power stations differs with each electric company. Thus, resources consumption and emissions per kWh of electricity are different with each electric company. It is, therefore, necessary to develop the inventories for electricity grid mix of each electric company for LCA practitioners in Japan. In this work, life cycle inventories for electricity gird mix of 10 electric companies in Japan have been developed. It was found that average CO2 emissions related to 1 kWh of electricity distributed by electric companies were 0.45 kg-CO2/kWh, whereas average SO2 and NOx emissions were 0.51 g/kWh and 0.47 g/kWh, respectively. Relative contribution of fuel production and fuel transport to CO2 emissions was 4-12 % of total emissions. On the other hand, relative contribution of fuel production and fuel transport to SO2 and NOx emissions was around 50 %. Average values of CO, CH4, NMHC and dust emissions were 1.3×10-4 kg/kWh, 1.3×10-3 kg/kWh, 3.3×10-4 kg/kWh and 2.4×10-5 kg/kWh, respectively. Heavy metal emissions into air were also investigated.
Life cycle inventories on packages of dishwasing detergent were calculated of the total energy consumption and CO2 emission during the material and package production stage. Additionally the survey was conducted to evaluate consumer's consciousness and activities on refill. It was concluded that the refill of compact type detergent in larger volume can reduce the most environmental load. Most of consumers recognize that the refill is usuful to reduce the environmental load. But there is no existing refill to be satisfied fully by the consumer.
Life cycle assessment (LCA) is expected to be a useful measure for us to evaluate environmental impacts associated with products or processes, so that we could improve our production systems for sustainable development. For this purpose, we have developed a novel mathematical tool called Process-relational Model. In the model, we have improved the principle of input-output analysis so as to include joint production. This improvement has enabled us to overcome difficulties of LCA in retracing complicated repercussions among production systems and in allocating environmental emissions among multiple products. Then life cycle CO2 emissions of electric and gasoline vehicles have been estimated with this model. We have shown that production and driving of electric vehicles cause less CO2 emissions than those of gasoline vehicles. Our analysis has also indicated that the difference detween electric and gasoline vehicles dramatically changes depending on traffic situation. Namely the difference becomes larger, as average velocity of vehicles becomes lower. Concerning electric vehicles, we have compared CO2 emissions caused by production with those caused by driving. The share of production has increased, as average velocity becomes higher. In conclusion, we have clarified directions of research and development of electric and gasoline vehicles for sustainable energy system.
It is necessary to introduce energy cascade systems and innovative technologies into the industrial sector in Japan. The aim of this study is to evaluate the effect of energy cascade systems on energy conservation with respect to substitution of a direct iron ore smelting reduction process for a blast furnace process. The following industries are assumed to be connected to an integrated energy center: steel & iron, cement, pulp & paper and ethylene. The authors have developed an energy cascading assessment model that integrates energy flows of industrial processes and energy conversion technologies minimizing the total primary fuel consumption. The results shows that energy cascading with the conventional iron process can save fuel consumption by 36% compared with a case without cascading. Moreover, the innovative ironmaking process enhances heat cascading and can reduce about half the fuel consumption. The model is useful to evaluate technologies from the viewpoint of total fuel consumption of combined industries.
Nippon Coal Oil Co., Ltd.has conducted the R&D of the 150 t/d Coal Liquefaction Pilot Plant (PP) since 1984. The trial runs for coal-feeding and the regular runs confirmed that the NEDOL process is an excellent coal liquefaction process in a large-scale pilot plant, as follows: (1) The synergetic effect of the low-cost fine-iron liquefaction catalyst and hydrogen donor solvent used in the NEDOL process proved to be effective for producing a high yield of naphtha-fraction-rich liquefied oil under the mild reaction conditions.(2) Through the continuous 80-day coal-feeding operation, operating skills were acquired, and the excellent operation stability of the process was confirmed. The objective of this report is to elucidate the countermeasures of the issues on runs and the effect of reaction conditions on product yields.