Optimal gas treatment and coal blending for reduced emissions in power plants: A case study in Northwest Spain

In this work a decision making framework for the design of the flue gas treatment section of a power plant has been developed, including particle, NOx and SO2 removal operations. It has been applied to a coal based thermal power plant in Spain to select the optimal technologies and its sequence. Surrogate models for the treatments have been developed. The problem corresponds to a mixed integer non-linear programming one including catalytic and non-catalytic NOx removal, allowing various allocations for the catalytic technology, electrostatic precipitation and wet or dry SO2 removal. It is reformulated as a nonlinear problem to evaluate bypass opportunities. The optimization suggests the use of electrostatic precipitation, followed by catalytic NOx removal and dry SO2 removal. Next, a coal blending problem has also been solved for two objective functions. When only treatment costs are considered, the use of imported coal is recommended, but an increase of 4% in its price can change the decision into the use of national coal. If the energy within the coal is added to the objective function, crude tar coal is included in the blend and imported coal is used to maintain the emissions within limits. Limestone Forced Oxidation is the selected technology. (C) 2018 Elsevier Ltd. All rights reserved.