Electrify Europe 2018

Sessions Speakers Exhibitors Products Press Releases Floor Plan Buzz

On-line Optimization of a Complex Industrial Power Plant Using Novel Fast and Accurate Modeling Approach (Room Lehar 3)

The Austrian steel company voestalpine supplies its Linz site with an industrial power plant consisting of six gas-fired power blocks. The main task of this plant is to convert the energy contained in the off-gases of blast furnaces, the coking plant and the steel mill into power, steam, and district heat. The plant is also interacting with the power market, as it is purchasing or selling energy at the power exchange. In parallel to the introduction of a trading system for gas and electricity which optimizes intra-day to long-term contracts considering storage facilities for coke oven gas, a so-called ‘Short-term Optimization System’ was established to advise the operators on how to implement the production plan by providing advice on the actual set points for the gas distribution, for buffering of blast furnace and converter gases, and for the power blocks. This optimization is of specific complexity, as it must be very fast to cope with a highly fluctuating load profile due to the batch processes of the steel making, it must span several upcoming time periods for storage management, and it must be accurate to ensure that no technical constraints for the plant in terms of maximum ramp rates or flow or temperature limits are violated. The Time Line Optimization (TLO) System by VTU was chosen to perform this challenging task. The TLO system can be characterized as follows: • high accuracy based on detailed thermodynamic models • very fast calculation speed, and • a powerful optimization algorithm that manages 44 set points, 79 hard constraints, and 46 soft constraints for 8 subsequent time periods. The system is operational and fully integrated into the plant information system of voestalpine, and an off-line version with Excel user interface is also available for the technical and commercial departments for analysis of past operating periods as well as planning purposes. Selected examples of how the TLO system benefitted the plant will be presented.