Conventional coal-fired power plants utilize steam turbines to generate electricity, which operate at efficiencies of 35–37 percent. Operation at higher temperatures and pressures can lead to higher efficiencies. Oxy-combustion comes with an efficiency loss, so it will actually increase the amount of CO2 to be captured. But without so much N2 in the flue gas, it will be easier and perhaps more efficient to capture, utilize and sequester.
NETL’s Advanced Combustion Project will conduct tests of advanced oxycombustion capture technologies that show continued achievement toward the goal of 90 percent CO2 capture at no more than a 35 percent increase in electricity cost.
Advanced Combustion Research Overview
The Advanced Combustion Project addresses fundamental issues of fire-side and steam-side corrosion in oxy-fuel combustion environments. NETL’s advanced ultra-supercritical (A-USC) steam autoclave provides a unique capability to examine long-term steam oxidation as a function of pressure.
Oxy-combustion Environment Characterization
Laboratory and field testing will address fire-side corrosion issues during oxy-fuel combustion. Scale morphologies from the lab tests will be compared with utility exposures to assess the importance of each test variable for acceptance of laboratory data in scale exfoliation models.
Results of this work will provide information on the performance of materials in oxy-fuel combustion environments. Research on steam-side corrosion addresses the effect of pressure on steam oxidation in A-USC conditions for test alloys and determines the role of each oxidant in mixed-oxidant conditions. Evaluating the effect of pressure on steam oxidation is important because this aspect is poorly understood.
Alloy Manufacturing and Process Development
Research is aimed at designing alloys and developing manufacturing processes that can be practically and economically utilized to produce full-scale components for deployment.
Work in alloy design and large-scale castings and forgings has focused on alloy design to produce large-scale heat resistant Ni-based and steel castings as well as Ni-based and steel forgings. Collaboration with industry partners has been pursued to facilitate the supply and process development of large-scale Ni-based superalloy castings for power plant applications.
NETL has also been working on developing superior heat resistant 9-12 percent Cr ferritic/martensitic steels with creep life better than existing commercial alloys.
Impact and Benefits
Advances in oxy-combustion technology will be instrumental in improving power generation efficiency while lowering the amount of CO2 produced and concentrating the CO2 effluent streams, making them suitable for carbon capture and sequestration. The Advanced Combustion Project represents an integrated, cross-functional approach and will lead to a better understanding of environmental and mechanical behavior of alloys.