Optimal Integration of the Flue Gas Heat for the Minimization of the Energy Penalty of Oxy-fired Power Plants
Résumé
Oxy-fired coal power plants require the recycling of flue gas to dilute the oxygen in order to moderate the combustion in the boiler. This induces a significant structural modification of the boiler and flue gas train compared to air-fired power plants, offering the opportunity for new thermal integrations opportunities.
In this study, a methodology allowing the assessment of the net plant efficiency increase brought by finely integrating heat sources into the steam cycle with minimal simulation runs is used for the comparison of several flue gas heat valorization layouts. Three configurations described in literature have been compared to an alternative option aiming for the minimization of exergy losses. For each of those configurations, the net plant efficiency after integration has been assessed and compared to an air-fired power plant in order to determine the energy penalty induced by carbon capture. Results show that the proposed alternative leads to promising energy performances: a net plant efficiency increase of 0.5%LHV can still be obtained compared to the already integrated base-case, reducing the energy penalty from 7.1%-pts down to 6.5%-pts.