Numerical simulation of oxy-fuel combustion for gas turbine applications

Abstract

Relevant reduction on worldwide greenhouse gases emissions shall be based on more efficient power generation systems linked to a carbon capture and storage technology (CCS). Integrated gasification combined cycle and natural gas combined cycle (IGCC) would play an effective role to these objectives. To that, oxy-fuel combustion is an important alternative for the implementation of CCS technology, claiming, however, modifications to the conventional operation of gas turbines combustors.This work presents CFD simulations of oxy-fuel combustion in a can-type model gas turbine combustor. Equilibrium combustion model for non-premixed flames was used to model chemical reactions and turbulence was accounted for by Reynolds Stress Model (RSM). Numerical predictions were carried out after validating the numerical schemes and turbulence model. In addition to the baseline (propane/air combustion) four oxy-fuel cases were studied: propane and syngas oxy-fuel combustion with two different O2/CO2 ratios.The predictions showed that the propane/oxy-fuel flame (O2/CO2 = 1) resembles the baseline case (propane/air) though, with much higher temperature levels in the central core of the combustor, resulting in a poor gas turbine combustor pattern factor. The oxy-syngas flames showed intense reactions in the primary zone, before the first dilution holes, leading to a very good patter factor.The numerical model proposed for this study can be considered a relevant tool in the preliminary design phase of gas turbine combustors applied to CCS technology.