Joe Yip, a researcher at FE's National Energy Technology Laboratory, uses laser-based Rayleigh light scattering to measure flame density and speed over a flat flame burner. Oxyfuel combustion, using oxygen in place of air with diluents such as steam or carbon dioxide, can reduce pollutant emissions in advanced power cycles using gas turbines. Photo courtesy of NETL Multimedia.
The workhorse of America's electric power sector is the coal-fired power plant. Today, coal combustion plants account for more than half of the Nation's electric power generation. Largely because of these plants, U.S. consumers benefit from some of the most affordable power rates in the world.
The technology of burning coal has made remarkable advances in the last quarter century, and much of this progress is due to federal research and development partnerships with private sector developers.
In the 1990s, fluidized bed combustion - a process that removes pollutants inside the coal boiler - was termed "the commercial success story of the last decade" by a major power industry publication. The first new coal-fired power plant to be built in Illinois in more than 15 years will employ a new type of "low-emission boiler" technology developed in the federal government's energy program. Innovations in burner designs, refractory materials, and high-temperature heat exchanges are all products of the Department of Energy's research program into cleaner, more efficient ways to burn coal.
Advanced combustion power generation combusts fossil fuels in a high-oxygen (O2) concentration environment rather than air. This eliminates most, if not all, of the nitrogen (N2) found in air from the combustion process, resulting in flue gas composed of CO2, water (H2O), contaminants from the fuel (including coal ash), and other gases that infiltrated the combustion system. The high concentration of CO2 (≈70 percent) and absence of nitrogen simplify separation of CO2 from the flue gas for storage or beneficial use. Thus, oxygen-fired combustion is an alternative approach to post-combustion capture for carbon capture and storage (CCS) for coal-fired systems.
However, the appeal of oxygen-fired combustion is tempered several challenges, namely capital cost, energy consumption, operational challenges of supplying O2 to the combustion system, air infiltration that dilutes the flue gas with N2, and excess O2 that mu
Advanced combustion power generation combusts fossil fuels in a high-oxygen (O2) concentration environment rather than air. This eliminates most, if not all, of the nitrogen (N2) found in air from the combustion process, resulting in flue gas composed of CO2, water (H2O), contaminants from the fuel (including coal ash), and other gases that infiltrated the combustion system. The high concentration of CO2 (≈70 percent) and absence of nitrogen simplify separation of CO2 from the flue gas for storage or beneficial use. Thus, oxygen-fired combustion is an alternative approach to post-combustion capture for carbon capture and storage (CCS) for coal-fired systems.
However, the appeal of oxygen-fired combustion is tempered several challenges, namely capital cost, energy consumption, operational challenges of supplying O2 to the combustion system, air infiltration that dilutes the flue gas with N2, and excess O2 that must be removed from the concentrated CO2 stream. These factors mean oxygen-fired combustion systems are not affordable at their current level of development.
Advanced combustion system performance can be improved by two means:
- Lowering the cost of oxygen supplied to the system; and
- Increasing the overall system efficiency.
The Advanced Combustion Systems Program targets both of these possible improvements through sponsored cost-shared research into three key technologies: (1) Oxy-combustion, (2) Chemical Looping Combustion (CLC), and (3) Enabling Technologies/Innovative Concepts. NETL is funding projects within each of the above-mentioned approaches. These R&D efforts are being performed both externally by industry, research organizations, and academic institutions, and internally through NETL’s Office of Research and Development (ORD).
In 2016 U.S. Department of Energy (DOE) has selected eight projects to develop enabling technologies for advanced combustion systems, including oxy-combustion and chemical looping–based power systems. The total estimated federal investment in the eight projects exceeds $10 million. In addition the Department also invested $28M to advance cleaner fuel-based power generation. The new projects, which span 11 states, will accelerate the scale-up of coal-based advanced combustion power systems, advance coal gasification processes, and improve the cost, reliability, and endurance of solid oxide fuel cells.
