IMPACT OF COMPONENT PERFORMANCE ON THE ALLAM CYCLE EFFICIENCY: AN EXERGY ANALYSIS

Carbon capture technologies represent a crucial step towards the decarbonization of power production. The most common alternatives focus on separating the CO2 from the power plant's exhaust, which markedly increases the power plant's footprint and complexity and reduces the net power output. A promising alternative is innovative power cycle development, which allows for a much easier CO2 separation. The Allam cycle represents one of the most advanced and close to deployment of these cycles. The Allam cycle is a semi-closed cycle with oxyfuel combustion, which allows for the CO2 direct separation from the cycle fluid in the supercritical state - a considerable advantage compared to post-combustion CO2 removal technologies. Here, the focus is on a straightforward configuration with the following main parts: compression, internal heat regeneration, power production, heat rejection, water condensation, and separation, designed to produce up to 300 MW. The paper focuses on the Allam cycle performance analysis at different combustor outlet temperatures and recuperator dimensions, highlighting the actual cycle performance when conservative considerations are made compared to the assumptions and results already obtained in the literature. Results demonstrate that maximum recuperator UA from 30000 to 45000 kW/K is required, and a reduction of the combustor outlet temperatures from the highest to the lowest analysed values leads to a decrease in the net electric efficiency of around 5 percentage points. An exergy analysis is also conducted to examine the performance of each component and its impact on the overall system in terms of losses, helping to pinpoint the cycle's sources of thermodynamic inefficiencies at the component level.