Boiler Performance Improvement Due to Intelligent Sootblowing Utilizing Real-Time Boiler Modeling on UP® Boilers
S. J. Piboontum, S. M. Smith, and R. S. Conrad The Babcock & Wilcox Company Barberton, Ohio, U.S.A.
Presented to: Electric Power 2005 April 5-7, 2005 Chicago, IL, U.S.A
Boiler Performance Improvement Due to Intelligent Sootblowing Utilizing Real-Time Boiler Modeling on UP® Boilers S. J. Piboontum The Babcock & Wilcox Company Barberton, Ohio, U.S.A. Presented to Electric Power 2005 April 5 - 7, 2005 Chicago, Illinois, U.S.A. S. M. Swift The Babcock & Wilcox Company Barberton, Ohio, U.S.A. R. S. Conrad The Babcock & Wilcox Company Barberton, Ohio, U.S.A. BR-1766
To achieve optimum boiler operation and performance it is necessary to control the cleanliness and limit the fouling and slagging of the heat transfer surfaces. Historically, the heating surfaces were cleaned by air-blowing, steam-blowing, or water-blowing sootblowers on a scheduled time-based interval. With the advent of fuel switching strategies such as changing from bituminous to Powder River Basin (PRB) subbituminous coals to reduce emissions, the control of heating surface cleanliness has become more problematic for many steam generator owners. A scheduled cleaning approach does not easily address changes in operation. Also, as power plant operators push to achieve greater efficiency and performance from their boilers, the ability to more effectively optimize cleaning cycles has become increasingly important. Sootblowing only when and where it is required to maintain unit performance can reduce unnecessary blowing, save on blowing medium utilization, and reduce tube erosion and wear. The Babcock & Wilcox Company’s (B&W’s) core technology for boiler design is based on modeling of boiler heating surfaces to establish heating surface requirements and performance. The modeling process also must consider fuel types and the combustion requirements. This same technology is used to model the expected performance of existing units. By establishing the boiler model it is possible to accurately determine when and where heating surfaces are experiencing diminished performance due to ash buildup and fouling. The ability to model the heating surface and determine real-time cleanliness indexes is important in developing a system that can more accurately initiate the cleaning cycle of the boiler heating surfaces. The performance of the individual convection pass banks is interrelated; consequently, determining the best sootblowing program must not only rely on the cleanliness of the specific bank to initiate or trigger blowing. By coupling the real-time cleanliness index data with the measured operating parameters of the boiler it is
possible to establish strategies to drive sootblower operation. Presented in this paper is the approach taken by B&W in developing the Powerclean™ system, a sootblowing optimization system. Also presented are the performance improvements made with the Powerclean system at two utilities in the United States (U.S.) – one utility located in the southern states and AEP Rockport Unit 2. It should be noted that these units are supercritical, B&W Universal Pressure® (UP) boilers which are operated differently from subcritical natural circulation drum boilers. UP boilers often behave and are controlled differently when they slag and foul; thus, the control of slagging and fouling is often more difficult and complicated.
Power generation from coal
More than 50% of the power generated in the U.S. is from coalfired power plants. Coal will continue to be a dominant fuel source for fossil-fuel steam generation into the foreseeable future. Pressure to reduce the emissions of sulfur dioxide (SO2), nitrogen oxides (NOx), mercury (Hg) and carbon dioxide (CO2) make it imperative for owners to seek cost effective strategies to meet the regulations. One option being used by an increasing number of...