Power scheduling and real-time optimization of industrial cogeneration plants

• Power scheduling application of cogeneration plants uses a first principle, steady-state, non-linear model.
• Process model tuned continually with plant data and also used for real-time optimization.
• Scheduler results are implemented using a model predictive controller.

Scheduling of power and real-time optimization for three industrial cogeneration plants at one of Dow's Louisiana site is presented in this paper. A first principle mathematical model that includes mass and energy balances for gas turbines, heat recovery units, steam turbines, pressure relief valves and steam headers is used to formulate an optimization problem to recommend the best strategy to trade power. The model has detailed operational information that includes equipment status and control curves for different operating scenarios. The model can also accurately predict the effect of ambient temperature, thereby resulting in an optimal day-ahead schedule. Adjustment of power schedule is done in the real-time market 30 min prior to the hour and implementation of the dispatched power schedule is done using a model predictive controller.