Steam Grid Stability Using Advanced Process Control and Real Time Optimization in an Alumina Refinery

The Hydro AlunorteHydro Alunorte refinery has a complex steam system composed by boilers and power generation turbines that use three types of fuel (heavy oil, coal, and electrical energy) to produce steam for the Bayer process. Due to the complex nature of the refinery and the variable price of fuels, two programs integrated directly with the plant Distributed Control SystemControl system (DCS), aiming to improve energy efficiencyEfficiency and steam system stability, reduceReduce greenhouse gas (GHG) emissionEmissions and avoid cascaded plant shutdowns. Advanced Process ControlProcess control (APC) controls boilers load, steam headers pressure and minimizes relief valves opening. Real Time OptimizationReal-time (RTO) is above APC and is responsible for giving the best configuration to the steam matrix, based on fuel price. This paper will describe how both programs can help steam grid to be stable and financially optimized for the refinery.