Improving fuel utilization in steel mill operations using linear programming
Abstract This paper describes the use of linear programming to improve the fuel utilisation at a major Midwestern steel mill. In particular, linear programming is used to determine an efficient fuel allocation plan for this steel mill, which reduces the total fuel costs for the steel mill operations. The efficient fuel allocation plan that is developed utilises two externally purchased fuels: natural gas and fuel oil, and two gases: blast furnace gas and coke plant gas, which are internally generated as natural by-products of the production process. Test results from the application of the linear programming model are presented and discussed, and indicate that considerable cost savings can be achieved by utilizing a fuel allocation plan which more effectively utilizes the by-product gases which are produced within the steel making process.
Gasholder level control based on time-series analysis and process heuristics
A novel method to control gasholder levels in an iron and steel company with accurate prediction of the future trend is presented. Although various gasholders are used to recycle by-product gases generated during the ironmaking, coke-burning, and steel-making processes, the capacities of these gasholders are insufficient to handle large amounts of gases. To overcome this problem, tight control of the gasholder level should be maintained by predicting their anticipated changes. However, the current prediction logic cannot show satisfactory results due to the lack of characterization of the relevant processes. In the proposed method, time-series modeling and heuristics from industrial operators are used to correctly reflect the process characteristics and deal with unexpected process delays. By applying the proposed method to an off-line data set, a significant reduction in the discrepancy between predicted values and actual values was observed. The method is expected to be adopted in the prediction system of POSCO.
Comparison of a Radiometric Procedure with Conventional Methods for Identification of Neisseria
A radiometric procedure was compared with the conventional cystine tryptic agar (CTA) sugar fermentation method for identification of Neisseria species. Four different ATCC cultures of Neisseria were identified by both procedures with identical results. The only difference noted was that the radiometric procedure required 3 h for completion, whereas the conventional CTA sugar method required overnight incubation. The radiometric procedure was also compared with the fluorescent antibody (FA) and CTA methods for identification of Neisseria gonorrhoeae. The organisms examined were gram-negative, oxidase-positive diplococci isolated from 49 clinical specimens sent to the laboratory for bacteriological analysis. Results obtained by both CTA and FA procedures were comparable. However, the radioisotope method appeared to be superior to the other two methods in that only one isolate identified as positive by both the CTA and FA methods was not identified radiometrically, whereas four isolates positive by the radiometric method were not identified by the other two procedures. Thus, a total of seven more positive identifications were made radiometrically than by either of the two other methods. All positive identifications were confirmed by a reference laboratory. These results indicate that the radiometric procedure is more rapid and reliable as compared with both the CTA and direct FA methods and, thus, may serve as a valuable addition to the methodology available for diagnostic microbiology.