Effect of heavy fuel oil/natural gas co-combustion on pollutant generation in retrofitted power plant

The purpose of this paper is to examine effect of co-combustion of heavy fuel oil and natural gas on the pollutant formation: CO2, SO2, SO3, NOX and soot. The analysis was carried out by means of numerical simulation on the case of retrofitted steam generator furnace of Thermal Power Plant Sisak (Croatia). Comprehensive mathematical model of the furnace with detailed 3D mesh was set up to include all relevant aerodynamic and thermo-chemical processes in the furnace. Dedicated model for SO3 formation was developed earlier and used in this work. By increasing the natural gas contribution in overall fuel fired in the furnace, emissions of CO2, SO2, soot, NOX and SO3 decreased. Heat transferred to the furnace walls and temperature field in the furnace were also examined in order to establish regions of safe and efficient boiler operation for different operational regimes.