Application of Expert System to Blast Furnace Operation

Abstract The practical expert system has been constructed for the support of blast furnace operation in Kimitsu Works of Nippon Steel Corporation. The systen has been developed with great efforts by considering the following points. (1) As blast furnaces have unknown factors derived from complex mixture of solid, liquid and gas inside furnaces, mathematical models- of the process cannot be obtained. Therefore, conventional control methods are not effective to control blast furnaces. (2) Skilled operators have a lot of knowledge to control blast furnaces properly. Hence we have established the practical system which can operate blast furnaces reasonably based on knowledge engineering technology. The knowledge to support blast furnace operations is summarized into four types of knowledge (daily operations. measures against contingency. shut-down guidance and trouble-shooting of equipment). Knowledge representation is as follows. (1) Interim hypothesis (an interim judgement) is produced by sensor data and output of existing systems. (2) The type and degree of deterioration trend of blast furnaces is estimated on the basis of interim hypothesis, and control actions are determined by referring to this estimation. This expert system named ALIS has been in practical use for No.3 & No.4 Blast Furnaces since June, 1988 and its contribution have been estimated under real operat ion.