Integration of Post-Combustion Capture and Reinjection Plant to Power Generation Cycle Using CO2-Rich Natural Gas in Offshore Oil and Gas Installation

Abstract

The use of CO2-rich natural gas (%CO2 ≈ 20%mol) for power generation in offshore hubs results in simpler upgrade process, while imposes an extra challenge to mitigate emissions. Power generation via combined cycle configurations and post-combustion capture with CO2 reinjection are investigated for carbon-footprint reduction, while increasing gas export and oil production, respectively. The processes are simulated using Aspen HYSYS software and compared to currently installed simple cycle configuration in terms of footprint, weight, power, efficiency and CO2 emissions. The combined cycle including two gas turbines and one single-pressure steam cycle (CC 2:1:1) results in the most favorable power system, having 53% efficiency, 476.8 gCO2/kWh emissions and similar dimensions compared to the simple cycle. The integration of a post-combustion capture sending the CO2 for enhanced oil recovery results in 241 gCO2/kWh for the CC 2:1:1 and 251 gCO2/kWh for the simple cycle, without great impacts in total efficiency. The CC 2:1:1 with post-combustion capture presents higher net efficiency, lower dimensions and greater economic advantages, enabling emissions reduction without having significant impacts on the power generation.