查看更多>>摘要：During the production of steel in electric arc furnaces, dioxins and furans are produced, depending on the scrap quality, which call for further waste gas cleaning. In view of the waste gas flow dimension to be treated (mostly 1 mill. m~3/h) and this industrial sector's sensitivity to investments, waste gas cleaning processes are needed which permit technically efficient and still economically justified environmental protection. Adsorptive waste gas cleaning using Activated Lignite HOK in an entrained phase process, the so-called entrained-phase technology, constitutes one of the simplest and at the same time lowest-cost cleaning steps. Successful application of the HOK technology in five European electric steel mills has proven that process-integrated adsorption based on Activated Lignite HOK allows reliable pollutant reduction to dioxin and furan concentrations below 0.1 ngTE/m~3 to be achieved even for large waste gas flows. Dioxin reduction is implemented with comparatively low out-lays as entrained-phase adsorption is integrated into the existing waste gas dust separation system. This integrated environmental technology was developed to a major extent by RWE Power AG (formerly Rheinbraun AG) which has decades of experience in the application of activated lignite for waste gas cleaning.
查看更多>>摘要：Various industrial pollution control laws and regulations were established in Japan to reduce health problems caused by pollution. Japan steel industry has been setting up regulations on pollution control since 1950s,followed by the government in late 1960s. The industry's self regulation started with the establishment of Water Pollution Committee in JISF and followed by numerous movements by both the JISF and the Government. The factors behind the deterioration of the environment pollution in Japan in 1960s until 1970s are high economic growth, regional concentration of production activities and delay in creation of social capital and changes in values due to the emphasis on industrial development. Polluted air and water had caused severe diseases in many areas in Japan. Eventually environmental control countermeasures emerged due to dramatic changes in social attitudes toward environmental deterioration followed by changes in political moves. In 1971, Environment Agency was created with jurisdiction over environmentalpolicy. Strict environmental quality and emission standards have been established to prevent pollution related health problems. To comply with the laws and regulations, the Japanese steel industry had spent an enormous investment in pollution control in a short period of 1973 - 1987. Furthermore, the JISF created various committees on pollution prevention started with Works Waste water Committee and Dust Prevention Countermeasures Committee. Finally, Japan has been enjoying improvement in air and water quality as a result of the stringent pollution countermeasures.
查看更多>>摘要：The continuous annealing line (CAL) has been widely adopted to anneal the coldrolling steel strip. China Steel Corporation (CSC) introduced CAL to its cold rolling mill in the 1980' s. In CAL, steel strip is heated by a radiant tube (RT) burner, which fires COG fuel gas. After 2-3 years' operation, it showed that the top left hand side of RT is vulnerable to be ruptured owing to the left-eccentric burner design. To solve this problem, a series of tests have been conducted to investigate the influence of burner design and operation parameters on the RT life and NOx emission. The investigated operation parameters include burner load, off-stoichiometric combustion, total stoichiometric ratio (PHI_T), primary stoichiometric ratio (PHI_1) , secondary air swirl number (Sg), etc. From the experiments, it has become apparent that NOx concentration increases with burner load, that the initial left-eccentric combustion exhibits lower NOx emission than the bottom-eccentric flame, that NOx formation is quite low in the fuel-rich combustion region until the CD T reaches nearly 0.8, and that PHI_1 and Sg has little and more effect on the NOx concentration for the left-eccentric combustion respectively. Finally the suggested low NOx operation parameters for the left- and bottom-eccentric combustion are PHI_1 =0.55 & Sg = 0.0 and PHI_1 =0.35 & Sg = 0.56 respectively. From the temperature measurements, it is found that the bottom-eccentric flame has a better temperature uniformity for the RT outer surface. This worse temperature distribution for the left-eccentric flame is attributed to the fact that combustion occurs too close to the RT top surface, which results in a higher localized temperature occurring at the top RT outer surface.
查看更多>>摘要：The purposes of knowledge management in POSCO are to organize scattered knowledge, a vast amount of knowledge and know-how owned by individual employees and systems into systematic company's intellectual property, to uplift work efficiency and productivity by providing the knowledge to the ones who need and when needs and to cultivate knowledge workers to retain competitive strength of global top level. According to KM (Knowledge Management) promotion stages, POSCO has passed by activating KM and learning organization, is now under way to improve performance. POSCO KM consists of process controlling life cycle of knowledge, reward system, KMS(Knowledge Management System) and culture relevant to user' s mind and change management program. This study will explain know-how how to develop these constituents of KM successfully. That is 96.8 percent of employees surveyed claimed that KM helped improve their work efficiency. Our study indicates that KM improved work speed by 32 percent on the average. Particularly, CoP(Community of Practice) activities by raising interests and creating new knowledge are divided into Job Learning CoP, Integrated Knowledge CoP, Information Exchange CoP and Sharing Work Standards CoP in order to prevent accidents and disasters, have made possible accelerate to create integrated knowledge supporting problem solving and to improve the competency of individuals and the organization through autonomous learning in the production process.
查看更多>>摘要：In the high-tonnage, low-margin business of electric arc furnace (EAF) steelmaking, incremental improvements can contribute significantly to earnings. Feedback of process information to the operator and engineers is the key to continuous improvement of the operation and maximizing earnings. In many EAF operations, the only cost indicators from process feedback consists of electrical energy, oxygen and natural gas consumption along with optimization indicators such as power-on time, tap-to-tap time, and yield. In modern EAF operations, the total amount of energy lost through the off-gas (both sensible and calorific heat) can be up to 45 percent of the total energy input to the EAF. Monitoring of the energy inputs and losses continuously using Smart-Gas allows EAF operators and engineers to identify periods of the operation where the energy transfer efficiency to the steel is low. During these periods the energy input to the EAF is underutilized and inefficiently used. This paper describes the use of the Smart-Gas system, developed by WorleyParsons GCT, as a simple tool for tracking EAF energy efficiency and providing real-time feedback to steel-making operations. The Smart-Gas system is low maintenance, consists of low-cost instrumentation, and provides continuous, real-time information on the energy efficiency of the EAF.
查看更多>>摘要：At Aichi Steel, byproducts of the stainless steel production such as EAF dust and sludge were disposed in landfills even though they contained the valuable materials (nickel and chromium). In order to recover these materials and thereby realize a production cost saving and contribute to zero emissions activities, a new recycling method using briquetted byproducts into EAP was developed. The technical points of this method are as follows: Proper blending ofbyprocducts, a reductant, and a binder to improve recovery yield Optimization of EAF slag composition to prevent slopping Installation of briquette charging equipment to maintain EAF productivity As a result of the development of this recycling method, the recycling ratio of stainless steel dust has increased from 18 percent to 86 percent.
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