Process integration of solar thermal energy with natural gas combined cycle carbon capture

• EGR (exhaust gas recirculation) can be used to reduce the specific energy penalty of the NGCC (natural gas combined cycle) power plant.
• Compressed gas to capture in the pre-combustion case reduces the energy penalty.
• Solar thermal reduces total energy penalty, increases specific energy penalty.
• Solar thermal and EGR leads to comparable reboiler duties compared EGR base case.

This project investigates the energy cost of CO2 capture for NGCC (natural gas combined cycle) power plants and studies the effect of solar thermal energy on the energy penalty for such a system.The gas turbine used in this study is the ALSTOM GT26. Alongside the standard case, other cases include an EGR (exhaust gas recirculation) and a pre-combustion case that utilises EGR with the capture taking place after the compression stage of the gas turbine. The solar thermal technology used in these simulations is a solar tower system capable of reaching 1000 °C. The integration of the solar energy is used to provide heat to the first of the two combustion chambers in the gas turbine. Cases are optimized for 75% capture.For a NGCC it was found that using EGR decreased the specific energy penalty as well as capture energy penalty. The pre-combustion case showed a reduction in the energy penalty over the standard and EGR cases but at a reduced capture rate. The addition of solar thermal shows a reduction in the total energy penalty. This is due to a reduction in the total CO2 produced in the system, hence a reduction in the total CO2 captured.