著者

秋山 友宏 八木 順一郎

出版者

社団法人日本鉄鋼協会

雑誌

鉄と鋼 (ISSN:00211575)

巻号頁・発行日

vol.74, no.12, pp.2270-2277, 1988

被引用文献数

3 14

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Exergy analysis was conducted on three ironmaking systems which were conventional ironmaking, direct reduction-electric furnace and smelting reduction systems. The exergy analysis is better than an enthalpy balance or a heat balance because exergy can express the quality of energy and evaluate different forms of energy like chemical, thermal, pressure and mixing energy by a unified measure.<BR>According to the calculated results for the specified conditions, the smelting reduction system was the lowest in net exergy loss, however, the highest in overall output exergy. The development of the efficient heat recovery process is therefore required for this system. The direct reduction-electric furnace system was the highest in net exergy loss. However, nonfired pellets were found to be effective to reduce net exergy loss. In the conventional ironmaking system, net exergy loss of its constituent processes significantly depended on the injection rate of pulverized coal and on the charging amount of nonfired pellets.

著者

工藤 純一 八木 順一郎

出版者

一般社団法人 日本鉄鋼協会

雑誌

鉄と鋼 (ISSN:00211575)

巻号頁・発行日

vol.73, no.15, pp.2020-2027, 1987-11-01 (Released:2010-01-19)

参考文献数

26

被引用文献数

8

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An attempt was made on the simultaneous analysis of the gas flow and heat transfer in the blast furnace by a mathematical model which considered complex structure and nonuniform sink and source terms for both heat and mass. ERGUN'S equation was used for the equation of motion of gas and potential flow approximation was used for the equation of solid flow. Two dimensional distribution for the velocities of gas and solid was obtained numerically by applying the finite element method with quadratic elements. Fundamental equations of heat transfer on gas and solids were composed of the terms for convection, heat exchange and heat source. Numerical computation of the fundamental equations was carried out in accordance with the method of characteristics. In this analysis, sink and source terms regarding fusion of ore in the cohesive zone and combustion of coke in the raceway were incorporated in the mathematical model as well as radial distributions of particle size and void fraction. It was consequently found that the temperature distribution was affected principally by nonuniform gas flow and thermal flow ratio. Within the cohesive zone, strong consumption of heat by fusion of ore and decrease in the solids velocity appeared. These phenomena affected significantly the temperature distribution in the lower region of the blast furnace together with the generation of heat in the raceway region.

著者

秋山 友宏 八木 順一郎

出版者

社団法人日本鉄鋼協会

雑誌

鐵と鋼 : 日本鐡鋼協會々誌 (ISSN:00211575)

巻号頁・発行日

vol.73, no.12, 1987-09-04

著者

秋山 友宏 高橋 礼二郎 八木 順一郎

出版者

社団法人日本鉄鋼協会

雑誌

鐵と鋼 : 日本鐡鋼協會々誌 (ISSN:00211575)

巻号頁・発行日

vol.73, no.15, pp.2108-2115, 1987-11-01

被引用文献数

2

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In order to make a clear evaluation of overall energy requirement for the production system of directly reduced iron through pellet from iron ore powders, exergy analysis was applied to the two systems. The first one consists of pelletizing, firing and reduction processes (Fired pellets method) and the second one includes pellets curing process instead of firing process (Cement bonded pellets method). Being compared with enthalpy balance, exergy analysis has two advantages in that the exergy expresses the quality of energy and evaluates different kinds of energy like chemical, thermal, pressure, mixing energies and so on by a unified measure. As a result of exergy analysis, fired pellets lose less exergy than cement bonded pellets in the reduction process in a shaft furnace. As the overall system, however, exergy requirement in the cement bonded pellets method is about 50% of that in the fired pellets method. This marked difference is caused by the large exergy loss in the firing process. Furthermore, exergy loss in the production of cement bonded pellets will be decreased by decreasing the amount of cement added as binder.

著者

八木 順一郎

出版者

社団法人日本鉄鋼協会

雑誌

鐵と鋼 : 日本鐡鋼協會々誌 (ISSN:00211575)

巻号頁・発行日

vol.73, no.15, 1987-11-01

著者

秋山 友宏 八木 順一郎

出版者

社団法人日本鉄鋼協会

雑誌

鐵と鋼 : 日本鐡鋼協會々誌 (ISSN:00211575)

巻号頁・発行日

vol.82, no.3, pp.177-184, 1996-03-01

被引用文献数

3

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The concept of zero emission of waste material in the manufacturing process has been focussed worldwide for more efficient utilization of fossil fuels and environmental protection. In this study, background and feasibility of symbiotic ironworks based on this concept were discussed from the state-of-the-art technology in catalyst and heat storage/transportation. One possibility is ironworks with methanol industry, in which charged coke is partially replaced by natural gas and the hydrogen-enriched blast furnace offgas (BFG) is used as raw material for methanol synthesis. The results of systematic analysis demonstrated that this system leads to not only exergy saving but also less emission of greenhouse gas (GHG). The key technology is to develop a catalyst for BFG of CO_2-CO-H_2 system. Another one is "urban-symbiotic ironworks", where excess outflow energy from ironworks is efficiently employed as a utility for household affairs. The use of latent heat and reaction heat is being planned in this system for thermal energy recovery and transportation. Possible energy recovery processes for the waste heat remaining in the ironmaking industry was reviewed, together with the detailed concept of 'urban-symbiotic ironworks' as an energy supplier. In particular, the use of phase change materials (PCMs) and of hydrogen storage alloy as the new technologies was fundamentally promising.