Emissions’ reduction of a coal-fired power plant via reduction of consumption through simulation and optimization of its mathematical model

Abstract

One of the main sources of carbon dioxide emissions is the electrical power production by fossil fuels (coal). 84% of the electrical power generated in Greece (source:Regulatory Authority for Energy) comes from lignite combustion and therefore optimized operation of the conversion system will result in higher efficiencies of the combustion and the water/steam circle. Thus, more electrical power can be generated with less fuel and less emissions. That forms our motivation for the modeling, simulation and optimization of a lignite fired power plant. An electrical power production unit, with 300 MW maximum output, has been chosen to model (similar to Greece KARDIA IV unit). For this purpose two software programs, using iterative method solvers, have been used. One is the open source code D.N.A. (Dynamic Network Analysis) and the other is gPROMS by the Process System Enterprise. The advantage of the former is that it consists of a library with the models of the components of a power plant and the steam/water properties but it does not include an optimizer, while in the latter, the user has to code the component models and the steam/water properties but it includes a non-linear optimizer, which is necessary due to the non-linearity of the problem. Simulation of the steady state operation of the power plant was successful and the optimization software showed an increase of ~1.42% in the efficiency of the water/steam cycle by regulating the steam mass flow rates at the extractions from the different stages of the turbines. Simulation of the boiler of the unit had also been performed with satisfactory results, in comparison with the measurements done in the control room of the unit.