Session: 06-01 Carbon Capture Integration

Paper Number: 153157

Gas Turbine Combined Cycle System Integration With Exhaust Gas Recirculation for Boosted Power and Improved Carbon Capture Operations 

Mitigating climate change by reducing anthropogenic greenhouse gas emissions is crucial to limiting global temperature increase to 1.5°C and achieving the objectives of the Paris Agreement. GHGs have been recognized as the primary cause of the rise in global mean temperature and climate change. Various measures must be implemented to prevent further increases in CO2 emissions and mitigate global temperature rise.  As per the IPCC's 2018 special report titled "Global Warming of 1.5°C," our remaining carbon budget is estimated to be 580 gigatons of CO2. This budget gives the world a 50-50 chance of limiting global warming to 1.5 °C over pre-industrial levels.

Reducing Carbon Capture Plant CapEx and sizing are key factors in accelerating combined cycle power plant decarbonization. One of the most promising technologies for lowering carbon capture plant costs and improving performance is exhaust gas recirculation (EGR). Exhaust Gas Recirculation is a technique for reintroducing a portion of the exhaust gas into the gas turbine's inlet after proper cleaning and conditioning. The EGR flow is mixed with fresh ambient air at the compressor inlet.

This paper discusses various aspects of integrating exhaust gas recirculation (EGR) with combined cycle and carbon capture plants. EGR provides valuable advantages, including reduced carbon capture plant size and CapEx, improved performance, lower CCP operational costs, increased CO2 capture potential, and improved combined cycle part load efficiency. The directed flue gas to the CCP is proportionally reduced by the EGR rate. The reduction in mass flow to CCP reduces the size of some major CCP components. Furthermore, EGR increases the concentration of CO2 in exhaust gases, resulting in a higher CO2 partial pressure in the flue gas, which can improve the separation process and performance.

The paper also examines the various operational aspects of EGR, such as increasing CO2 capture rate and improving combined cycle efficiency during part load operation. The amount of EGR is constrained by the O2 concentration at the GT combustor inlet, combustion dynamics, and emissions. As the EGR ratio increases, the concentration of O2 in the gas turbine combustor decreases. Maintaining the O2 concentration at the gas turbine inlet above certain limits is essential for preventing challenges with combustion stability and dynamics. The paper discusses the gas turbine combustion operation with EGR, as well as its limitations.

Presenting Author: Majed Sammak GE Vernova

Presenting Author Biography: Majed Sammak has 15 years of experience with combined cycle, carbon capture, and systems modeling and integration. Majed received his PhD from Lund University in oxy-fuel gas turbine. Majed is the Carbon Capture System Integration Leader at GE Vernova.

Authors:

Majed Sammak GE Vernova
Parag Kulkarni GE Vernova
Tiffany Camp GE Vernova
Todd Denman GE Vernova
Gian-Luigi Agostinelli GE Vernova