Study of combustion in CO2-Capturing semi-closed Brayton cycle conditions

The implementation of the Kyoto Protocol, the Paris Agreement, the directive 2018/410 of the European Union and other similar assessments, have placed greater demands related to the control of carbon dioxide emissions on the governments of the signatory countries. This fact has aroused interest not only in renewable energies, but also in new methods to produce power from fossil fuels without releasing greenhouse effect gases to the atmosphere. Within these new power generation methods, the ones where the combustion is performed with pure oxygen are particularly interesting, in order to reuse existing combined-cycle machinery. This article performs an analysis of combustion's phenomenology when it is achieved in conditions derived from semi-closed cycles with oxy-combustion for CO2 capture. The study was performed using Computational Fluid Dynamic (CFD) methods for reacting flows. Chemical reactions were modeled using the detailed GRI-Mech 3.0 mechanism and were taken into account in the CFDs using the Eddy Dissipation Concept model (EDC). The effect of different pressure ratios of the compression stage was analyzed. It was found that the coflow composition, apart from modifying the temperature field, also has an important impact on the boundary conditions that the High Pressure Turbine (HPT) may found at its inlet.