Process modelling and simulations of an integrated oxy-combustion CHP plant

This work presents the process modelling and simulation of an integrated combined heat and power (CHP) plant under different fuel and carbon capture configurations. The study was developed using the gPROMS Process modelling environment and is based on a reference coal-fired CHP plant with a thermal capacity of approximately 300 MWth and an electrical capacity of 100 MWe. First, a reference model of a hard coal-fired CHP plant was developed and used as a baseline for further analyses. Subsequently, hard coal was replaced with biomass to represent a common approach of fuel switching in order to decrease CO2 emissions. In the next step, a post-combustion carbon capture unit based on monoethanolamine (MEA) absorption was integrated with the CHP plant. The results indicate that the integration of the MEA-based CO2 capture system leads to a significant reduction in the available thermal output, of approximately 30%, while the decrease in electrical power generation remains relatively small. Finally, an oxy-combustion configuration was investigated through a black-box model of an oxy-MILD boiler which was developed based on results from CFD simulation results and subsequently integrated with the previously developed reference CHP model. The simulations show that the boiler capacity decreases by approximately 10% compared with the conventional configuration. As a consequence, the thermal capacity of the integrated CHP plant is reduced by approximately 15% relative to the reference case. The developed modelling framework enables a consistent comparison of conventional power plant with technologies aiming to reduce CO2 emissions. The results provide insight into the performance penalties associated with the integration of low-carbon and carbon capture technologies and demonstrate the potential of combining detailed CFD results with system-level process modelling.