Aimed at oxygen scheduling challenge under the scenario of blast furnace blow-down in integrated iron steel enterprises

a control strategy based on short-term shutdown of air separation units (ASUs) was proposed with an establishment of optimal scheduling model for oxygen distribution system by the mixed integer linear program. The objective of model optimization was to minimize overall oxygen pressure across high pressure oxygen piping network during entire scheduled cycle. The model included constraints for temporary shutdown and restart of ASUs and some oxygen compressors

as well as stop and run time thresholds of these equipment in real situations. A case study of a mega integrated iron and steel enterprise in China was performed to examine rationality and feasibility of the proposed model and to analyze effects of shutdown time threshold of ASUs on scheduling target by the model. The results show that a shorter shutdown time-threshold of ASU is generally propitious to achieve more optimal objective

which relationship between time-threshold and scheduling objective has non-linear leaping characteristic.