FGD & DeNOx Abstracts
December 2009
HH 09 12 01 “Wet Position Booster Fans for Reduced Power Consumption and Optimized Environmental Performance of Power Stations with FGD and Wet Stack” by Marco Rossi and Carlo Acquistapace, Alstom Power Italia S.p.A., Lewis Maroti and David Anderson, Alden Research Laboratory, Inc. and Albert de Kreij, Hadek Protective Systems bv. Presented at Coal-Gen 2009, Charlotte, NC, August 2009, 8 p.
The FGD booster fans for the 330 MW lignite-fired units at Rovinari Power Station will be placed in the wet position (i.e. between the wet FGD scrubber and the wet stack), where they will consume significantly less power than in the more common “dry position” (i.e. in the hot, dry flue gas upstream of the FGD). In order to function well in the environment of desulfurized, water saturated flue gas, the booster fans are fabricated from corrosion-resistant materials and cleaned during operation through a regular wash cycle. Alden Research Laboratory has performed a study into the environmental benefits of using wet booster fans, considering that these heat up the treated flue gas by 3 to 5°C. The study included both thermodynamic calculations and physical tests using a laboratory scale model. The study showed that, at nominal unit load, a) the booster fans will have the capacity to evaporate small diameter droplets contained in the wet gas including all of the water from the fan wash cycle and b) raise the flue gas temperature sufficiently to enable the thermally-insulated, Pennguard-lined chimneys to maintain the flue gas temperature just above the water dewpoint, effectively eliminating condensate formation in the wet stacks. A properly-designed liquid collection system in the outlet ducts and the chimney breeching will still be needed to collect bigger droplets that may not have enough time to evaporate.
IH 210 LIMESTONE SCRUBBER, IH 520 FANS,
IH 509 STACKS, W ROMANIA
IH 514 MATERIALS OF CONSTRUCTION
HH 09 12 02 “Impact of Biomass Co-Combustion on SCR DeNOx Operation” by Hans Jenson-Holm, Peter Lindenhoff and Joakim Reimer Thøgersen, Haldor Topsøe A/S, Denmark. Presented at Power-Gen Europe, Cologne, Germany, May 2009, 18 p.
With increasing requirements for reductions of CO2 emissions from the power-generating industry, there is a considerable interest in the utilization of biomass and municipal and industrial waste in power plant boilers. Combined with still tighter limits on emissions of NOX, the use of biomass fuel represents a challenge to the designers of SCR units since the useful life of the SCR catalyst can be significantly reduced. Alkali-metal aerosols formed during combustion of biomaterial can at worst cause complete deactivation of the catalyst within a few thousand hours of operation. Other components, e.g. phosphorous, can cause severe fouling of the catalyst surface. The paper describes several cases of SCRs implemented to meet these new challenges and includes experience from a variety of power plants firing biomass in Europe and the U.S. Results from installations in units firing 100 percent biomass as well as installations in units with co-combustion of biomass with coal and oil are presented. These experiences demonstrate that with proper catalyst formulation, the negative effects can be limited. Up to 20 weight percent biomass can be co-combusted with the coal without any noticeable impact on catalyst lifetime. The use of SCR on 100 percent biomass-fired boilers may be done as a tail-end installation to minimize the amount of poisoning species entering the SCR.
C HALDOR TOPSØE, IH 410 SCR,
IH 421 CATALYSTS, IH 168 BIOMASS,
IH 467 CO-FIRING
HH 09 12 03 “Nebraska City Station Unit 2, Nebraska City, Nebraska” by Robert Peltier, Editor. Power, October 2009, 3 p.
Omaha Public Power District commissioned Unit 2 at its Nebraska City Station in May of this year. The new 682-MW unit joins Unit 1. The project is outfitted with all the requisite air quality control systems and sports a very good thermal efficiency. More importantly, the plant will provide reasonably priced power for customers of eight municipal utilities that share ownership of the plant’s electrical output.
IH 802 NEW CONSTRUCTION,
IH 453 COAL-FIRED BOILERS,
IH 330 SPRAY DRYERS, IH 410 SCR,
IH 540 CONTROL SYSTEMS,
C OMAHA PUBLIC POWER DISTRICT
HH 09 12 04 “Bull Run Fossil Plant, Clinton, Tennessee” by Robert Peltier, Editor. Power, October 2009, 3 p.
TVA’s 920 MW Bull Run power plant burns either medium– or low-sulfur coals from Central Appalachia. TVA contracted with Advatech for the installation of a wet FGD system on the plant in 2005, after installation of a SCR. The system entered commercial operation on December 13, 2008. The Bull Run FGD project met all of TVA’s design and construction requirements and was placed in service a month ahead of schedule and within budget.
IH 210 LIMESTONE SCRUBBING,
IH 816 RETROFIT, C ADVATECH
C TENNESSEE VALLEY AUTHORITY
HH 09 12 05 “Seminole Generating Station, Palatka, Florida” by Robert Peltier, Editor. Power, October 2009, 4 p.
After a decade of hard work and an investment of about $300 million, SECI can now say that the 2 X 650 MW Seminole Generating Station has reduced its air emissions well below what is required by the plant’s air permit and has minimized its solid waste disposal problems with a robust recycling program. The FGD systems were upgraded, low NOx burners and overfire air replaced the existing burners and SCR was retrofit. In fact, should the supercritical Unit 3 be built, the total air emissions of all three units will be less than those of just Units 1 and 2 a decade earlier.
IH 410 SCR, IH 210 LIMESTONE SCRUBBING, IH 460 LOW NOX BURNERS,
IH 466 OVERFIRE AIR, IH 212 LIMESTONE GYPSUM, C SEMINOLE ELECTRIC
HH 09 12 06 “DOE/NETL’s Advanced NOx Emissions Control Technology R&D Program” by Bruce W. Lani, Thomas J. Feeley, III, Charles E. Miller and Barbara A. Carney, U.S. Dept. of Energy, National Energy Technology Laboratory and James T. Murphy, Science Applications International Corporation. Power Engineering, November 2006, 6 p.
This article highlights the Department of Energy National Energy Technology Laboratory’s (DOE/NETL) advanced NOx emissions control research and development (R&D) efforts to provide more cost-effective options for coal-fired power plants to comply with ever more stringent emission limits. Advanced NOx emissions control technology R&D has been an important component of the Innovations for Existing Plants (IEP) program conducted by DOE/NETL. The current short-term goal of the research is to develop advanced in-furnace technologies for coal-fired power plants capable of controlling NOx emissions to a level of 0.10 lb/MMBtu by 2010, while achieving a levelized cost savings of at least 25 percent compared to state-of-the-art SCR technology. The program’s long-term goal is to further develop a combination of advanced in-furnace and SCR control technologies to achieve a NOx emission rate of 0.10/MMBtu by 2020.
C NATIONAL ENERGY TECHNOLOGY LABORATORY, IH 182 RESEARCH,
IH 460 LOW NOx BURNERS, IH 411 SNCR, IH 410 SCR, IH 400 NOx REMOVAL
HH 09 12 07 “Maintaining Combustors” by Meherwan Boyce, The Boyce Consultancy Group, LLC. Turbomachinery International, November/December 2006, 2 p.
Emissions are the key driver behind technology trends in gas turbine combustors. The typical stable and simple diffusion-flame combustor has been replaced by a staged combustion system with multiple injection fuel nozzles, which vary with turbine load. The staged system has to be monitored and tuned precisely for stability from starting to full load, while maintaining low emissions and avoiding flashback and high-pressure pulsations that could damage the combustor and other turbine components. The operation and maintenance of the staged system pose several challenges to users.
IH 445 GAS TURBINE, IH 460 LOW NOx BURNERS, IH 469 COMBUSTION CONTROL
HH 09 12 08 “Setting the Standard” by Douglas C. Comrie, Chem-Mod LLC, Stow, OH. PEi, September 2006, 3 p.
Chem-Mod is a multi-pollutant control technology that is emerging as a leading option for coal-fired energy companies, due to its low cost and easy integration with existing scrubber technology. The Chem-Mod Solution was first introduced to the U.S. market in February 2006. The company, Chem-Mod, is a privately owned environmental services company based in Stow, Ohio. Chem-Mod’s system uses an innovative sorbent-based technology to significantly reduce mercury, sulfur dioxide, arsenic, other heavy metals and chloride emissions.
IH 416 MULTI-POLLUTANT CONTROL,
IH 305 SORBENT INJECTION,
IH 401 SO2 REMOVAL, IH 159 HEAVY METALS
HH 09 12 09 “Charting the Future” by Don Labbe and Bill Hocking, Invensys, Foxboro, MA, Bill Ray, Entergy, Texarkana, TX, and Jon Anderson and Pat Klepper, Entergy White Bluff, Redfield, AR. Intech, December 2006, 4 p.
Electric power producer, Entergy, operates two 800 MW units at their White Bluff Station in Redfield, AR. Reducing NOx emissions was a main concern and led to a major project to retrofit the units with distributed control systems for the boiler and auxiliary controls. This retrofit would also extract heat rate benefits while trimming the frequency and duration of high steam temperatures. The results enhanced unit reliability, improved thermal performance, and provided continuous dispatch capability.
IH 400 NOx REMOVAL,
IH 540 CONTROL SYSTEMS,
IH 185 COMPUTER SERVICES, C ENTERGY