Using Ultra Super Critical (USC) steam cycle designs, coal power plants can gain a 10 percent increase in efficiency and a 25-30 percent decrease in CO2 emissions. ECE’s Anbo Wang is helping make this improvement a reality with a grant of more than $1 million from the Department of Energy’s National Energy Technology Laboratory (NETL) to develop fiber-optic strain, temperature, and pressure sensor technology.
The USC efficiency depends in part upon keeping the plants continually operational while staying within equipment and material limitations. The new USC boilers are designed to operate above 700°C and several thousand psi for steam, and higher for gas. According to Wang, “these higher temperatures and pressures require local measurements rather than the global process operation and control measurements available from the current generation of sensors. The local measurements are needed to assess equipment health or impending problems over and along the entire components area.” And none of the existing distributed sensor networks are rated for the necessary in-furnace conditions of a USC boiler.
Because of the higher operating temperatures, USC components degrade more rapidly. Although a component’s mean degradation can be predicted with existing systems, the precise state of each component is unknown. The estimates are overly conservative and susceptible to unanticipated component failure, Wang says.
The new sensors must operate at higher temperatures and pressures than the existing technology without sacrificing any accuracy or long-term operating reliability. They will also have multiplexed capability for a distributed sensor network, allowing for more accurate identification of those operating conditions that will adversely impact boiler reliability — and therefore plant operation.
Wang’s team is working with Gary Pickrell of materials science and engineering, who leads a team developing the sensor packaging and protection, and Alstom Power, which will identify the necessary environmental conditions and evaluate sensor attachment and placement.