Big Boiler Efficiency Increases - Hot Topic Hour March 24
Jeffrey Phillips, a Senior Program Manager at the Electric Power Research Institute (EPRI), provided an overview of the U.S. Dept. of Energy's and Ohio Coal Development Office's Advanced Ultrasupercritical Boiler and Steam Turbine Materials Development Program. This is a $50 million, 9-year effort aimed at increasing steam temperatures by more than 250°F above the current state-of-the-art. This remarkable effort has now resulted in a code case submission to the ASME Boiler Code committee for a new material which can operate at the targeted conditions. Approval of this material will open the door to the most significant improvement in the thermodynamic performance of coal-fired power plants in 50 years. You can learn more about this at an April 7 conference also covered in this Alert.
One of the important discussions following the talk was regarding the possibility to design new coal-fired boilers to eventually operate in the advanced ultrasupercritical state but to initially operate at efficiencies substantially higher than the old power plants they replace. So the old plants could be immediately replaced with major benefits. Then in 2020 when the advanced ultrasupercritical materials are commercial, the plants can be retrofitted for this additional efficiency boost.
Keith L. Pronske, President and Chief Executive Officer of Clean Energy Systems (CES), covered technology derived from the aerospace industry. Pressurized oxy-combustion of coal can create a zero emissions power plant. Future coal-based power generation systems may utilize de-carbonizing technologies that permit carbon dioxide (CO2) to be captured and stored. Oxy-combustion of gasified coal (synthesis gas or “syngas”) permits capture and utilization of high quality CO2. In the oxy-combustion power plant cycle proposed by CES, syngas and high-quality oxygen provided by an air separation unit (ASU) are combusted to form a working fluid composed primarily of steam and CO2. This high-temperature gas directly drives turbines to produce electricity, after which the steam is condensed and the CO2 is captured and stored. This technology enables use of coal or other hydrocarbon fuels with essentially zero atmospheric emissions. Biofuels can be gasified along with the coal. Thus this system would be even greener than solar or wind. It could be a net CO2 reducer. Every kWh of electricity generated results in extraction of CO2 from the atmosphere.
Duane S. Abbott of Beltran Technologies, Inc. discussed Wet ESPs (WESPs) for use on an IGCC power station, where there is acid mist removal required after the sulfuric acid plant which converts hydrogen sulfide to acid. He also discussed use of WESPs directly on coal-fired boilers in India. Beltran has over 1000 WESP installations around the world.
After the conference Duane posed this question for Keith. We hope to publish Keith’s answer next week:
“I found the other two presentations very interesting. One question on Keith's presentation. I've done a lot of work on oxygen enrichment including designing a "stackless" sulfuric acid plant using pure oxygen instead of air to burn sulfur and to convert the SO2 to SO3 (the plant was never built). The major issue was the cost of oxygen. I would guess the sensitivity to the changes in cost of oxygen is high. Does Keith intend to make his own oxygen from the power of the generator? If so he could sell the nitrogen, if not what is the emission factor for the oxygen plant?
The Bios, Abstracts and Photos are linked below.