Alliant Energy Corporation
Joseph J. Pieters
Combustion Initiative for Innovative Cost-Effective NOx Reduction
Sites: Sheboygan, WI and Portage, WI
Project Summary: Alliant Energy Corporation, Madison, WI, proposes to achieve the same, stringent nitrogen-oxide-emissions reductions as Selective Catalytic Reduction at a fraction of the capital cost and with drastically lower operation and maintenance costs. Alliance uses a computational modeling approach, its Combustion Initiative, to optimize overall power plant performance. The Combustion Initiative will attempt to hold NOx emissions to 0.15 lbs/mmBtu from a 340-megawatt cyclone boiler burning coal from the Powder River Basin at the Edgewood Generating Station in Sheboygan, WI. Cyclone boilers are especially prone to high NOx emissions; this demonstration could help establish a target baseline for combustion-stage NOx reductions on cyclone boilers.
The Energy Department selected this project for a partial award.
Public Abstract Submitted by Proposer: Alliant Energy's Combustion Initiative is a science-and-technology--driven approach to lowering emissions and improving the performance of coal-fired power plants. Through research and development, the company is finding innovative ways to reduce emissions, increase thermal efficiency, and improve plant reliability.
The Combustion Initiative is a methodology that starts with developing a deep understanding of the combustion and related processes in each piece of equipment and in the power plant as a whole. The second step is to push the envelope for existing NOx control technologies through re-engineering and modeling. The use of computational modeling as a tool is key to optimizing the system performance and maximizing the use of emission reduction technologies. The Combustion Initiative methodology results in the potential to reduce NOx emissions to 0.15 lb NOx /mmBtu or below, without the use of selective catalytic reduction (SCR) technology, and at a fraction of the capital cost and at much lower O&M costs. The ability to reach these low NOx emission levels has been demonstrated in the pilot-scale work that Alliant Energy has conducted at its M.L. Kapp Station in Iowa.
Alliant Energy proposes, through its Wisconsin Power & Light Company subsidiary, to demonstrate the reduction of NOx emissions using the Combustion Initiative methodology on three of the main coal-fired boiler types in the United States: T-fired, cyclone-fired, and wall-fired units. The three units include Edgewater Generating Station Unit 4 (cyclone) and Unit 5 (wall-fired) in Sheboygan, Wisconsin, and Columbia Generating Station Unit 2 (T-fired) in Portage, Wisconsin. Reduced emissions are directly in line with the company's commitment to improving the environment for everyone. Better thermal efficiency will mean that less fuel will be needed to produce energy, which saves money and reduces stress on equipment. Improved reliability will help keep customers lights on, even as demand grows throughout the region. Finally, when costs are minimized, shareowners will experience increased earnings. Through applied science and technology, the Combustion Initiative is helping Alliant Energy find cost-effective solutions to challenges the Power industry faces today and tomorrow.
Arthur D. Little, Inc.
Development of Hybrid FLGR/SNCR/SCR Advanced NOx Control for Orion Avon Lake Unit 9
Site: Avon Lake, OH
Project Summary: Arthur D. Little Inc., Cambridge, MA, proposes to develop and demonstrate a hybrid system composed of lower-cost components from three established NOx-reduction systems that can function as stand-alone units or as an integrated, optimized, single-control system. Using Fuel-Lean Gas Reburn/Selective Non-Catalytic Reduction, Selective Non-Catalytic Reduction, and Selective Catalytic Reduction systems, the hybrid seeks to lower NOx emissions to 0.15/mmBtu at lower costs than conventional SCR, a comparatively expensive, effective way to curb NOx. Improving performance and reducing compliance costs, the technology would be installed on a 623-MW, wall-fired unit near Cleveland, OH, that burns Eastern bituminous coal.
Public Abstract Submitted by Proposer: Coal-fired power boiler operators are facing a dual challenge to remain competitive while adapting to deregulation and to impending stringent NOx controls. The NOx control technologies available to coal-fired operators are not optimized for this new set of challenges. Under deregulation, the optimum control techniques need to have a low capital cost base, and cost basis, and cost effective reduction over a wide operational range so that the performance of each unit in the system can be optimized to allow maximum revenue dispatch. The increased flexibility is needed to allow each boiler and the integrated system to respond competitively to market conditions. Current reliance on selective catalytic reduction, with the associated high capital cost, will not typically give a utility sufficient dispatch flexibility to maximize competitiveness. As an alternative, the team of Acurex Energy, Fuel Tech and Orion Power are proposing development and demonstration of a hybrid system of lower cost components that can be operated separately or as an integrated, optimized single control.
The three components in the hybrid system are FLGR/SNCR, SNCR, and compact SCR. The three components have been developed individually, but have not been developed and optimized as a hybrid control. The objectives of this project are to demonstrate the hybrid as a lower cost alternative to SCR to achieve 0.15 lb/MMBtu emission levels, and to operate the hybrid system to improve performance and reduce compliance costs to enhance operation in system-wide dispatch in the deregulated market.
The hybrid system will be installed on Orion's Avon Lake Unit 9 boiler near Cleveland, Ohio. This is a 623 MW wall-fired unit firing eastern bituminous coal. Acurex Energy will perform the engineering and conduct the performance testing. Fuel Tech will supply the system hardware for the FLGR, SNCR and SCR modules. The system will be retrofit in February 2003 and tested and optimized during the 2003 ozone season. Long-term performance and emission monitoring will be done during the 2004 ozone season.
CONSOL Energy, Inc.
South Park, PA
F. P. Burke
Greenidge Multi-Pollutant Control Project
Site: Torrey, NY
Project Summary: CONSOL Energy Inc., South Park, PA, seeks to demonstrate a multi-pollutant-control system that can reduce NOx, SO2, acidic gas, mercury and fine particulate matter from a large number of smaller coal plants for less money than it costs to control NOx and SO2. This project would be the first to demonstrate 1) NOx reductions of 0.122 lbs/mmBtu using a single bed, in-duct Selective Catalytic Reduction combined with a low-NOx combustion technology on a unit burning coal and biomass, 2) 95% sulfur removal using a Circulating Dry Scrubber from Environmental Elements Corp. on a coal-fired boiler, 3) 90% mercury reduction in the CDS, and 4) more than 95% acid gas (sulfur trioxide, hydrochloric, hydrofluoric acids) removal in the CDS. The system is projected to offer 60% NOx removal for one-third of the capital cost and one-fourth of the operation and maintenance cost of conventional SCR or SNCR technology. Less complex than a conventional flue gas desulfurization system, the CDS is projected to cost less than half as much to install as an FGD system on a 100-MW unit, with substantially lower operation and maintenance costs. The technology will be demonstrated on a 104-MW unit in Torrey, NY.
Public Abstract Submitted by Proposer: CONSOL Energy Inc., AES Greenidge LLC, Environmental Elements Corporation (EEC), Foster Wheeler Energy Corporation (FWEC), and AEP Pro Serv, propose to install and test an integrated multi-pollutant control system on the 104 MW AES Greenidge Unit 4. The 4.5-year project would be the first to demonstrate:
- NOx emissions less than 0.122 lb/MM Btu using a single-bed, in-duct Selective Catalytic Reduction (SCR) unit, in combination with low-NOx combustion technology, on a unit firing coal and biomass
- SO2 removal of 95% using EECs Circulating Dry Scrubber (CDS) on a unit firing >2% sulfur bituminous coal
- Mercury reduction of 90% by the addition of activated carbon into the CDS
- Acid gas (SO3, HCI, HF) removal greater than 95% in the CDS
Greenidge Unit 4 is representative of 492 coal-fired electricity generating units in the United States with capacities of 50-300 MWe. These smaller units, almost one-quarter of the U.S. coal-fired generating capacity, are increasingly vulnerable to fuel switching or retirement as a result of more stringent state and federal environmental regulations. The proposed project will demonstrate the commercial readiness of an emissions control system that is particularly suited, because of its low capital and maintenance costs, to meet the requirements of this large group of smaller existing electricity generating units.
The single-bed, in-duct SCR, in combination with low-NOx combustion technology, can achieve 60% NOx reduction for about one-third the capital cost and one-fourth the operating and maintenance cost of a full SCR or Selective Non-Catalytic Reduction (SNCR) system on a 100 MW unit. The capital cost of the CDS system is projected to be less than half that of a conventional flue gas desulfurization (FGD) system on a 100 MW unit. Operating and maintenance costs are less, and reliability is better for the CDS system, because it is less mechanically complex than a conventional FGD. Activated carbon injection into the CDS unit is projected to use 5 to 10 times less carbon than direct injection into flue gas duct for a given level of mercury control, because the carbon has a greater average contact time in the CDS bed than in the flue gas duct. Reducing the carbon feed rate results in substantial mercury control cost savings. The CDS system will reduce acid gases (SO3, HCl, HF) by more than 95%, with the additional benefits of reducing plume visibility and secondary particulate formation. Acid gases must be reported to EPA as part of the Toxic Release Inventory (TRI). The project will also include an evaluation of the impact of biomass co-firing (5-10% of the boiler fuel) on the performance of the SCR and CDS systems.
The goal of the proposed project is to demonstrate substantial improvements in mercury, SO3 and fine particulate control, and substantial reductions in the cost for NOx and SO2 control, compared to conventional technologies when applied to the large number of smaller coal-fired generating units in the U.S. This project will produce operating and maintenance cost data, reliability and availability data, and process performance data so that generators will accept the risk of installing for multi-pollutant control on smaller coal-fired units. Ultimately, the successful demonstration of these technologies will help to ensure the future availability of low-cost electricity from a significant fraction of the U.S. coal-fired generating fleet.
Otter Tail Power Company
Fergus Falls, MN
Demonstration of a Full-Scale Retrofit of the Advanced Hybrid Particulate Collector Technology
Site: Big Stone City, SD
Project Summary: Otter Tail Power Company, Fergus Falls, MN, will demonstrate, in a full-scale application, a hybrid technology that raises the particulate matter capture of coal plants up to 99.99% by integrating fabric filtration and electrostatic precipitation in a single unit. The Advanced Hybrid Particulate Collector overcomes the problem of excessive fine particle emissions that escape collection in ESPs and the reentrainment of dust in baghouses. The AHPC would be retrofitted into an existing 450-MW EPS structure at a low-sulfur-coal plant in Big Stone City, SD.
Public Abstract Submitted by Proposer: A new concept in particulate control, called an advanced hybrid particulate collector (AHPC), is being developed under funding from the U.S. Department of Energy. The AHPC combines the best features of electrostatic precipitators (ESPs) and baghouses in an entirely novel manner. The AHPC concept combines fabric filtration and electrostatic precipitation in the same housing, providing major synergism between the two methods, both in the particulate collection step and in transfer of dust to the hopper. The AHPC provides ultrahigh collection efficiency, overcoming the problem of excessive fine-particle emissions with conventional ESPs, and solves the problem of reentrainment and re-collection of dust in conventional baghouses.
A slipstream AHPC (9000 scfrn) has been operating at the Big Stone Power Plant for the past 1½ years. The AHPC demonstrated ultrahigh particulate collection efficiency for submicron particles and total particulate mass. Collection efficiency was proven to exceed 99.99% by one to two orders of magnitude over the entire range of particles from 0.01 to 50 µm. The flue gas exiting the AHPC was as clean as pristine ambient air with a fine particulate matter level of 5 µg/m3. This level of control would be well below any current particulate emission standards. These results were achieved while operating at significantly higher air-to-cloth ratios (12 ft/min compared to 4 ft/min) than what is used for standard pulse-jet baghouses. In fact, preliminary economic analysis of the AHPC compared with conventional ESPs and baghouses indicates that the AHPC is economically competitive with either of these technologies for meeting current standards. For meeting a possible stricter fine-particle standard or 99.99% control of total particulate, the AHPC is the economic choice over either ESPs or baghouses by a wide margin.
The AHPC is a superior technology not only for new installations but as a retrofit technology as well. The AHIPC combines a high particulate collection efficiency, with a small footprint and potential economic advantages. Given the age and performance level of many existing ESPs, there is a great and immediate need for this type of retrofit technology.
Therefore, Otter Tail Power Company and its partners, Montana-Dakota Utilities and NorthWestern Public Service, is proposing to retrofit the AHIPC technology into an existing ESP structure at the Big Stone Power Plant. The overall goal of the project is to demonstrate the AHPC concept in a full-scale application. Specific objectives are to demonstrate ultralow fine particulate emissions, low pressure drop, overall reliability of the technology and, eventually, long-term bag life.
Sunflower Electric Power Corp.
Wayne E. Penrod
Achieving New Source Performance Standards (NSPS) Emission Standards Through Integration of Low-NOx Burners with an Optimization Plan for Boiler Combustion
Site: Garden City, KS
Project Summary: Sunflower Electric Power Corporation, Hays, KS, will install ultra-low-NOx burners with other combustion-stage controls with the goal to reduce NOx emissions to 0.13-0.14 lbs/mmBtu, demonstrating a concept that has never been illustrated in plants using subbituminous coals, including those from the Powder River Basin. Expected to help define the extent to which combustion modifications can reduce NOx from pulverized coal boilers, the project will be tried out on a 360-MW wall-fired unit in Garden City, KS.
Public Abstract Submitted by Proposer: Low-NOx Burners (LNB) have been in development since the late 1970s and are in general use on many steam-electric generating units. Increasing demands for overall reductions in nitrogen oxide (NOx) emissions have continued to put pressure on manufacturers to improve burner design. Recent developments have introduced what are generally referenced as ultra-LNB. When used with separated over-fire air (SOFA) they have been found capable of reducing emission rates very near the current new source performance standard (NSPS) level of about 0.16 pounds per million British thermal units (mmBtu).
The purpose of this project is to research and install the very best of the ultra-LNB available and, further, to install with them other new features all directed to enhancing the control of NOx during combustion to annual emission rates of about 0.13 or 0.14 lbs/mmBtu. Naturally, vendors are reluctant to guarantee emissions at or below the NSPS level. A practical demonstration of the best designed and controlled equipment will reduce the uncertainties and thus assure the availability of technology that has much lower installed cost than the Selective Catalytic Reduction (SCR) units that are now in favor. A portion of the technology proposed has been installed on one 600 MW wall-fired unit and it has achieved the NSPS level of NOx emissions, at least on a short-. term basis.
The full application of the five-elements proposed herein have never been demonstrated in plants tiring sub-bituminous coals, especially those from Wyoming's Powder River Basin (P RB). Likewise, there are no other wall-fired units on which owners have sought to fully explore the technology proposed to its fullest potential. The inclusion of the very latest in distributed control systems, proposed for this unit in 2003, make this location ideal for integration with the proposed elements. The unit on which this technology will be applied has among the very best availabilities and performance histories for boilers of its type. It was placed in commercial operation in 1983 and is equipped with the latest sulfur-dioxide (SO2) scrubber and fabric filter for particulate matter. When completed, this will be among the cleanest non-SCR equipped coal-fired units in the United States.
We believe there are as many as 30 units onto which this technology can be deployed that will be able to meet the current NSPS level, if long-term practical demonstration can be made. A further 60 units will be able to establish significant reductions, to levels of about 0.22 lbs/mmBtu. This choice of equipment, if enabled in a timely fashion, will allow a reduction in the number of SCRs being installed, thereby reducing the overall consumer cost; will reduce the outage duration necessary for completion, thereby improving the electric system reliability; and will conserve the critical manpower needed to accomplish this work, which is now in such short supply. Overall, some improvements in operating efficiencies are certain for this proposed unit, but the complexity of evaluating those on a fleet basis is beyond the scope of this proposal. The existing conditions on the proposed unit are such that additional capacity and energy may be generated with the addition of this equipment. While this condition may exist elsewhere, it also is beyond the scope of this proposal.
Tampa Electric Co.
Robert N. Howell
Polk Power Station Plant Improvement Project
Site: Mulberry, FL
Project Summary: Tampa Electric Company, Tampa, FL, proposes to demonstrate a monitor that measures the wear pattern of refractory liners at high temperatures, thereby increasing unit reliability and availability. The demonstration site is a 250-MW integrated gasification combined-cycle unit at the Polk Power Station in Mulberry, FL. The monitor is expected to reduce costs and uncertainty related to refractory wear and replacement for IGCCs, which are highly efficient, clean, coal-based, power-generation systems.
The Energy Department has selected this project for a partial award.
Public Abstract Submitted by Proposer: Coal is our nation's most abundant fuel resource. It is used primarily in power plants. However, coal contains up to 60% more carbon per unit of useful energy than liquid fuels or natural gas, so coal fired power plants are normally large sources for C02 generation and by-product source.
A new type of coal fired power plant called Integrated Gasification Combined Cycle (IGCC) has been developed, demonstrated, and commercialized in the United States and abroad. In IGCC plants, the coal is first converted into a high-pressure gas before combustion. Conventional pollutants and their precursors such as sulfur, nitrogen compounds and particulates are much easier to remove from this high pressure low volume gas stream in IGCC plants than from the low pressure high volume combustion products in power plant stacks. IGCC demonstration plants funded in part by the United States Department of Energy (DOE) under the Clean Coal Technology Program have already shown their environmental superiority in this regard. At this time, Polk Power Station is generating 250 MW (Net) of power, is operating at over 80% availability and is one of Tampa Electric Company's premier baseload plants. This same attribute of IGCC plants, a high-pressure low volume gas stream, which contains most of the fuels carbon, also offers the best chance to minimize the cost and demonstrate CO2 capture and recovery. The Polk Power Station project also offers an opportunity to demonstrate the full recycling of all coal streams from the gasification process. Within the gasification process, the ability to measure the wear pattern of the brick liner will also be demonstrated to increase unit reliability and availability including extended life. Tampa Electric's Polk Power Station which was placed in-service September 30, 1996 with over 25,000 hours of run time on the gasifier, provides the platform for demonstrating this project.
Phase I will include the complete process design and preliminary engineering. Phase II will consist of the detailed engineering and long lead-time equipment. Phase III will cover construction, startup, operation/demonstration and reporting of the results and conclusions.
The demonstrations proposed herein for the Polk Power Station will provide significant improvements to overall plant performance, plant reliability and plant operating costs thereby assuring the gasification technologies remain competitive for future power generation applications.
Tampa Electric Company
Robert N. Howell
Tampa Electric Company, Big Bend Power Station, Neural Network-Sootblower Optimization
Site: Apollo Beach, FL
Project Summary: Tampa Electric Company, Tampa, FL, seeks to control boiler fouling on a 445-MW demonstration unit in Apollo Beach, FL, by using a neural-network soot-blowing system in conjunction with advanced controls and instruments. Ash and slag deposition compromise plant efficiency by impeding the transfer of heat to the working fluid. This leads to higher fuel consumption and higher air emissions, especially NOx. This project is expected to reduce NOx by 30%, improve heat rate by 2% and reduce particulate matter emissions by 5%.
Public Abstract Submitted by Proposer: Cost effective generation of electricity is vital to the economic growth and stability of this nation. To accomplish this goal a balanced portfolio of fuel sources must be maintained and established which not only addresses the cost of conversion of these energy sources to electricity, but also does so in an efficient and environmentally sound manner. Conversion of coal as an energy source to produce steam for a variety of systems has been a cornerstone of modern industry. However, the use of coal in combustion systems has traditionally produced unacceptable levels of gaseous and particulate emissions, albeit that recent combustion, removal and mitigation techniques have drastically reduced these levels.
On such problem that exists with the combustion of coal, is the formation and deposition of ash and slag within the boilers which adversely affects the rate at which heat is transferred to the working fluid, which in the case of electric generators is water/steam. The fouling of the boiler leads to poor efficiencies due to the fact that heat which could normally be transferred to the working fluid remains in the flue gas stream and exits to the environment without beneficial use. This loss in efficiency translates to higher consumption of fuel for equivalent levels of electric generation, hence more gaseous emissions are also produced. Another less obvious problem exists with fouling of various sections of the boiler relating to the intensity of peak temperatures within and around the combustion zone. Total NOx generation is primarily a function of both fuel and thermal NOx production. Fuel NOx which generally comprises 20%-40% of the total NOx generated is predominately influenced by the levels of oxygen present, while thermal NOx which comprises the balance is a function of temperature. As the fouling of the boiler increases and the rate of heat transfer decreases, peak temperatures increase as does the thermal NOx production.
Due to the composition of coal, particulate matter is also a by-product of coal combustion. Modern day utility boilers are usually fitted with electrostatic precipitators to aid in the collection of particulate matter. Although extremely efficient, these devices are sensitive to rapid changes in inlet mass concentration as well as total mass loading. Traditionally, utility boilers are equipped with devices known as sootblowers, which use, steam, water or air to dislodge and clean the surfaces within the boiler and are operated based upon established rules or operators judgment. Without extreme care and due diligence, excursions or excessive soot can overload an ESP resulting in high levels of PM being released.
The intent of this project is to apply a neural network intelligent sootblowing system in conjunction with state-of-the-art controls and instruments to optimize the operation of a utility boiler and systematically control boiler fouling. This optimization process is targeted to reduce total NOx generation by +30, improve heat rate by 2%, and reduce PM emissions by 5%. As compared to competing technologies, this could be an extremely cost-effective technology, which has the ability to be readily and easily adapted to virtually any pulverized coal boiler.
Universal Aggregates, LLC
South Park, PA
David C. Kay
Commercial Demonstration of the Manufactured Aggregate Processing Technology Utilizing Spray Dryer Ash
Site: Birchwood, King George County, VA
Project Summary: Universal Aggregates LLC, South Park, PA, will design, build and operate an aggregate-manufacturing plant that converts 115,000 tons/year of spray dryer by-products into 167,000 tons of light-weight masonry blocks or light-weight concrete. Flue gas desulfurization systems, used to lower sulfur emissions from coal plants, often produce a type of sludge that is landfilled; only 18% of FGD residue is recycled. Much of that 18% pertains to recycling by-products from ‘wet' FGD systems or scrubbers. Universal Aggregates' process can be used to recycle the by-products from wet or dry scrubbers. This plant would reduce plant disposal costs while reducing the environmental drawbacks of landfilling. The demonstration site is the 250-MW Birchwood Power Plant in Birchwood, VA.
Public Abstract Submitted by Proposer: Universal Aggregates, LLC proposes to design, construct and operate a lightweight aggregate manufacturing plant at the Birchwood Power Facility in King George, Virginia.
The project team consists of CONSOL Energy mc, P.1. Dick, Inc., SynAggs, LLC, and Universal Aggregates, LLC. The Birchwood facility will transform 115,000 tons per year of spray dryer by-products that are currently being disposed of in an off-site landfill into 167,000 tons of a useful product, lightweight aggregates that can be used to manufacture lightweight masonry blocks or lightweight concrete.
In addition to the environmental benefits, the Birchwood facility will create eight manufacturing jobs plus additional employment in the local trucking industry to deliver the aggregates to customers or reagents to the facility. A successful demonstration would lead to additional lightweight aggregate manufacturing facilities in the United States. There are currently twenty-one spray dryer facilities operating in the United States that produce an adequate amount of spray dryer by-product to economically justify the installation of a lightweight aggregate manufacturing facility. Industry sources believe that as additional scrubbing is required, dry FGD technologies will be the technology of choice. Letters from potential lightweight aggregate customers indicate that there is a market for the product once the commercialization barriers are eliminated by this demonstration project.