Dynamic gas scheduling method for efficiency optimization of gas–steam–power energy conversion equipment and systems in steel plants

Improving energy conversion efficiency is essential for achieving low-carbon and high-efficiency operations in steel plants. To address the strong multi-energy flow coupling and time-varying characteristics of gas-steam-power systems, this study proposes an improved energy hub (EH) model. The model represents the real conversion structure as a topological network of heterogeneous energy conversion devices and subsystems and incorporates dedicated methods for energy flow allocation and dynamic efficiency calculation at both the device and system levels. A dynamic association function is established to continuously map the efficiencies of different device types to the overall system efficiency. Based on this model, a two-stage dynamic scheduling method is developed for surplus gas dispatch, with system energy conversion efficiency as the primary optimization objective. In the pre-optimization stage, the impacts of gas supply fluctuations on unit commitment are identified in real time, and the corresponding adjustment strategies are determined. In the precise optimization stage, the gas is finely allocated among the units according to the dynamic efficiency matrix of the improved EH model and the series-parallel coupling relationships of the multi-energy flows. Industrial data from a large steel plant were used for validation. Under normal conditions, the proposed method improved average system efficiency by 9.86% and reduced operating cost by 6.12%. Under maintenance conditions, the corresponding improvement in system efficiency was 5.16%, and the operating cost was reduced by 5.13%. The computation time remained on the order of seconds. The proposed method provides an efficient solution for scheduling complex energy conversion systems in steel plants.