You missed an important Hot Topic Hour yesterday, but thanks to streaming media servers you can view the recording at your leisure. The U.S. needs to catch up to China and Europe and replace its existing coal-fired boilers with supercriticals. The speakers indicated that this could be done as retrofits to existing plants. This makes both economic and political sense.
Bin Xu, Ph.D, CEng, MIMechE, Sr. Engineer at Doosan Babcock Energy America LLC, presented some of the design advancements Doosan Babcock has made to address the challenges of designing USC PC boilers employing ultra-supercritical steam cycles with steam temperatures exceeding 1110ºF (600ºC) and pressures greater than 4,000 psi (275 bar) for high safety, reliability and low cost. These USC boilers can be retrofitted to existing U.S. power plants at less cost than installing new boilers. This also will be politically more acceptable rather than a new greenfield power plant.
Brian Vitalis, Manager of Project Engineering at Riley Power Inc., discussed design considerations for ultra-supercritical boilers. Advanced ultra-supercritical (A-USC) steam cycle conditions are arguably the environmentally best choice to dramatically reduce CO2 emissions, resource consumption, and direct heating of surroundings on a meaningful scale. The pressure operating mode should be selected according to the particular market environment, which means that the appropriate choice in many regions of the U.S. may not be the same as that for Europe or Japan. While sliding pressure design and operation permits fast turbine load ramping, it offers negligible heat rate advantage across the load range and requires a larger and hotter furnace section compared to boilers designed for constant pressure operation. Especially as conditions approach A-USC, constant pressure design offers significant cost savings since the furnace may be made of low-chrome ferritic alloy material, rather than expensive nickel-based alloys likely required for sliding pressure design.
CO2_Decision_Tree/subscriber/aug14files/2009-08-USC-NotUltraExpensive-Vitalisrileypower.pdf
Calvin Hartman of WorleyParsons Group, Inc told the group that supercritical units now have the same availability and low maintenance features of subcritical units. The advanced steam conditions can be supplemented with the following positive design changes:
CO2_Decision_Tree/subscriber/aug14files/Supercrit Hot Topics worley parsons.ppt
Bob McIlvaine provided data on Chinese activity indicating large numbers of ultra supercritical units under design and construction. He observed that knowledge and technology is going to be flowing westward rather than the reverse. Participants questioned whether the right materials and operating procedures will be utilized, but if they are then China will be the leader in USC.
The bios, abstracts and photos can be viewed as follows: August 14, 2009 Bios, Photos, Abstracts - Hot Topic Hour.htm