Masao Itoh

Development Approach to the Combustor of Gas Turbine for Oxy-Fuel, Supercritical CO2 Cycle

As global demand for energy increases while environmental regulations tighten, novel power generation cycles are being developed to meet market needs while accommodating green requirements. The Allam cycle is an approach (with high pressure, low pressure ratios, oxygen-fuel combustion and CO2 as a working fluid) that efficiently produces power in a compact plant, avoids NOx emissions, makes efficient use of clean-burning methane (natural gas) and can generate high-pressure carbon dioxide for enhanced oil and gas recovery in the field. The cycle requires oxy-fuel-CO2 combustion at approximately 30MPa and 1150° C turbine inlet temperatures.Due to its relatively compact size (owing to the high operating pressures), the Allam cycle technology can be implemented for a low cost in relative existing power plants, and given the current economic climate, natural gas is the most financially appealing application. Meeting environmental regulations for decades to come, the cycle can dramatically lower the cost of electricity.The critical path for plant implementation lies in demonstrating efficient, stable combustion at 30MPa. Similar pressures have been demonstrated in rocket engine systems, where reusability typically means 3 to 4 hot fires and surviving 8 to 32 minutes lit. The technical challenge here lies in designing durable hardware capable of thousands of hours of continuous operation and efficient combustion over the range of conditions required in a power plant. Production of clean CO2 exhaust (ideally, free of O2 and CO) is another challenge that will drive plant viability.Copyright