Library: Technical Papers: Environmental Projects - B&W

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BR#1866

Multi-Pollutant Control Demonstration in a Pilot Plant with Dry Sorbent Injection

New regulations on emissions from fossil fuel powered combustion facilities require tighter controls on SO₂, HCl, particulate and mercury. Dry sorbent injection (DSI) technology offers a low capital-cost solution to control these emissions or in the case of mercury, to enhance its capture. DSI is therefore being considered as part of a utilities overall multi-pollution mitigation strategy. This paper describes DSI tests for acid gas control conducted at the Babcock & Wilcox Research Center. Separate test programs focused on multi-pollutant control targeting SO₂, sulfuric acid (H₂SO₄) and HCl emissions. Sorbents used for mitigation include trona, hydrated lime and sodium bicarbonate. A description of the test program and results, including competing reactions of these pollutants, is discussed.

BR#1856

Deactivation of SCR Catalyst by Phosphorus: Proposed Mechanism and Solution

Exposure of SCR catalyst to coal combustion flue gas results in the deactivation of catalyst. Utilities firing PRB coal with air staged combustion have been experiencing rapid deactivation of SCR catalyst. This paper presents the results of long-term combustion additive injection testing to demonstrate reduction in the rate of catalyst deactivation and thus, improvement in SCR catalyst life using B&W's patent-pending combustion additive as compared to earlier experience. Results will also be presented for simultaneous phosphorus mitigation and mercury oxidation using a blended combustion additive.

BR#1851

Low Cost Multi-Pollutant Control Solution Demonstration

While dry sorbent injection (DSI) for acid gas control is not a new concept, it has taken on a new life in anticipation of more stringent regulations such as the Industrial MACT and Utility MACT as well as the Clean Air Transport Rule (CATR). Field demonstrations have been ongoing to develop design and performance guidelines and comparative reagent economics. Discussions of field data and how they relate to CATR and MACT as well as the impact of a fabric filter and/or ESP on emission control and reagent performance are presented. The test results will not only address acid gas control but also the overall impact on multi-pollutant control.

BR#1848

Scale-up and Operational Flexibility for Clean Coal Technology Carbon Capture Systems

Low carbon electricity production is the logical progression for future use of coal as a primary power generation fuel. Carbon capture system development has matured to the point of near-commercial scale demonstrations and now focuses on scale-up. Oxy-coal combustion is one technology being considered for carbon capture and near-zero emissions. Post-combustion capture, like the B&W PGG RSAT™ CO₂ scrubbing system, is another technology for carbon capture. The commercial development of carbon capture systems must now take on the added requirements of flexibility to meet changing power demand profiles and generation technologies in the growing market. With the issue of scale-up, oxy-coal and RSAT CO₂ scrubbing are ready to meet these challenges.

BR#1847

RSAT^™ Process Development for Post-Combustion CO₂ Capture: Scale-up from Laboratory and Pilot Test Data to Commercial Process Design

It is believed that a regenerable solvent absorption technology process is the most viable near-term technology for post-combustion CO₂ capture from power plant flue gas. B&W PGG has deployed a suite of research tools to evaluate and develop its RSAT^™ CO₂ scrubbing technology, including laboratory, pilot-scale, and simulation modeling capabilities. This paper presents the scale-up protocol used in evaluating the RSAT process which encompasses both laboratory and pilot-scale testing as well as rate-based modeling to achieve a commercial-scale RSAT process design. Solvent screening research activities recently conducted within B&W PGG successfully demonstrate the scale-up protocol used for RSAT process development. The time and cost of process development can be significantly reduced through rigorous rate-based modeling in conjunction with laboratory experiments and pilot plant validation.

BR#1846

Pollution Control Technology for the Cement Industry

The control of pollutants from cement kilns is becoming a major concern in the Americas. Emission limits for HCl, mercury (Hg), particulate matter (PM), hydrocarbons, dioxins, furans and nitrogen oxides (NO_x) have just been set to Maximum Achievable Control Technology (MACT) requirements in the United States. New limits for sulfur dioxide (SO₂) emissions, H₂SO₄ and NH₃ are anticipated. The capture of CO₂ may also be required. This paper reviews some of these pollutants, the emission limits and the control technologies.

BR#1845

Fayette Power Project Unit 3 FGD Upgrade: Design and Performance for More Cost-Effective SO₂ Reduction

Lower Colorado River Authority's (LCRA) Fayette Power Project - Unit 3 was completed in 1988. The original wet FGD system design was to reduce sulfur dioxide (SO₂) by approximately 90% across the absorbers, while burning high-sulfur Texas lignite and bypassing up to 20% of the flue gas. In the future, the station will require 95.5% SO₂ capture without flue gas bypass, while firing 1% sulfur Powder River Basin (PRB) coal. Sargent & Lundy performed an FGD upgrade study that identified a concept for achieving these goals. BE&K, and their subcontractor, B&W PGG, were selected as the supplier for these modifications, which included new spray headers, the addition of trays, turning vanes, and a new mist eliminator system. Non-proprietary details of the design modifications as well as actual performance data comparing the original installation and the modified installation are presented in this paper.

BR#1844

Multi-Technology, Mercury Abatement Program, Implementation and Performance at Nova Scotia Power

Nova Scotia Power Incorporated (NSPI) has installed mercury capture technologies on seven coal-fired boilers to comply with provincial regulations for mercury emissions. This paper discusses program implementation and performance test results at seven NSPI boilers using the combination of calcium chloride injection technology with Powdered Activated Carbon (PAC) injection upstream of the particulate collection devices.

BR#1843

Influence of Filter Media on Secondary Capture of SO₂

Filter media used in fabric filters serve to control filterable particulate. These filter media capture the suspended particulate forming a filtering bed or cake. This cake promotes an environment of close contact between suspected condensable acids and gases which can react with suspended alkaline particulate. Two filter media were investigated with results reported.

BR#1842

Technical Considerations for Oxycombustion Flue Gas Conditioning

With oxycombustion, the emissions of particulate matter, sulfur dioxide (SO₂), nitrogen oxides, and mercury will be below current reliable EPA measurement levels. The dramatic difference in flue gas composition between air firing and oxycombustion, as well as process requirements such as minimal air infiltration, have significant impact on equipment design. B&W PGG has successfully developed oxycombustion through lab testing, 30 MWth pilot testing, and a rigorous integration and optimization analysis. It is now ready for at-scale demonstration leading to full-scale commercialization.

BR#1841

Deactivation of Selective Catalytic Reduction (SCR) Catalyst by Phosphorous: Proposed Mechanism and Possible Solution

A number of power plants burning western PRB coal have experienced an unanticipated rapid deactivation of catalyst during the SCR process. This deactivation phenomenon has been primarily observed at SCR installations firing PRB coal with staged combustion. As a possible solution to reduce or eliminate rapid catalyst deactivation, full-scale field test results applying B&W PGG patent-pending additive technology at Black Hills Power's 100 MWe Wygen II unit are presented. Results obtained so far have indicated the effectiveness of this technology on reducing gas-phase phosphorous concentration entering the reactor.

BR#1839

Solvent Selection for Commercial Deployment of B&W PGG's RSAT™ CO₂ Scrubbing Process

B&W PGG is conducting a comprehensive CO₂ solvent selection methodology in support of the commercial deployment of B&W PGG's RSAT™ CO₂ scrubbing process. Solvent screening focuses on the next generation of CO₂ solvents with fast CO₂ absorption kinetics, high capacity, and low heat of absorption. Solvent related physicochemical properties such as chemical stability and environmental impact were also seriously considered when judging the potential of a specific candidate solvent.

BR#1838

Predicting PAC, Hydrated Lime and Trona Injection Effectiveness in Flue Gas Systems Using CFD and Physical Flow Analyses for Optimized Nozzle Design

Powdered activated carbon, hydrated lime and trona injection is being developed by B&W PGG to reduce unwanted chemical constituents in the outlet flue gas stream of boilers. Effective injection can reduce the total sorbent usage while maximizing the removal rates for the unwanted chemicals. To optimize an injection system, computational fluid dynamics is used as a cost-effective tool to assist in the design. Based on initial physical and CFD model testing, the most promising designs were optimized to design a sorbent injection system for an existing coal fired boiler flue-work arrangement using just the CFD analysis. These results and conclusions are reviewed and discussed.

BR#1837

Oxy-Coal is Ready for Demonstration

This paper describes the work leading up to the current state-of-the-art of B&W PGG and Air Liquide's oxy-combustion technology as well as presenting the demonstration and commercial reference plant designs.

BR#1835

Determination of Wet FGD Limestone Reactivity

Limestone reactivity is a determinant of limestone-based wet FGD system performance. Accurate estimation of this parameter is necessary for absorber performance modeling and absorber design. Most methods determine the relative reactivity, which provides a measure of reactivity as compared to a reference limestone of known performance. Presently, an industry standard is not available and a number of different procedures exist for conducting such measurements. This paper discusses methodology for determination of limestone reactivity.

BR#1834

NO_x Reduction Strategy Using a SOFA System in Tangentially Fired Boilers at Lingan Generating Station

Nova Scotia Power (NSPI) operates four coal-fired generating stations supplying about half of the province's electricity needs. NSPI began assessing options to reduce NO_x emissions in 2005 and embarked on a multi-phase plan to reduce overall NO_x emissions by at least 40%. This paper addresses strategic planning, design considerations, and performance test results of the separated overfire air (SOFA) NO_x reduction program at the Lingan Generating Station.

BR#1832

Use of Numerical Modeling for Designing a Biomass-fired BFB Boiler Air System for Low NO_x Emissions

The air system design for future low-emission BFB boilers is a challenging task due to a large number of factors such as number of combustion air stages, number of ports, port spacing, and port momentum with added constraints on other operating parameters. In this scenario, use of numerical modeling tools such as computational fluid dynamics (CFD) provides invaluable support in evaluating new design concepts. The methodology and the findings from such a low-NO_x air system design effort are presented in this paper.

BR#1826

Construction of a Robust, Highly Reliable Wet FGD Unit Retrofit at Detroit Edison Monroe Station

The absorbers that are part of the wet FGD retrofit at Detroit Edison Monroe Power Plant are constructed of ceramic liner plate-lined concrete, with 2205 duplex stainless steel internal components and outlet hood. This paper addresses all major aspects of the project, from initial design considerations for absorber shell material selection based on process pH and chlorides content through design and construction challenges.

BR#1825

Oxygen-Enriched Combustion of a PRB Black Thunder Coal for NO_x Reduction in a Cyclone Furnace

Pilot-scale emissions performance results are reported for the combustion of a western sub-bituminous Black Thunder Powder River Basin coal with air and oxygen-enriched air in a cyclone furnace. Optimum emissions results represent 88% NO_x reduction from the uncontrolled operation.

BR#1824

Selective Use of Oxygen and In-Furnace Combustion Techniques For NO_x Reduction in a Wall-Fired Pulverized Coal Burning Pilot Boiler

A NO_x minimization strategy for pulverized coal-burning units was developed that includes deep air staging, innovative oxygen use, reburning, and advanced combustion control enhancements. Computational fluid dynamics modeling and pilot-scale tests were applied to refine and select the best arrangements.

BR#1823

CO₂ Chemical Solvent Screening

Characterization of the recently installed wetted-wall column (WWC) apparatus in the CO₂ Control Laboratory was conducted at B&W's Research Center in Barberton. Screening of new solvents with the characterized WWC was also performed. The preliminary results indicate promising thermodynamic and kinetic properties for a new solvent for post-combustion CO₂ capture. Experimental work is ongoing to gather fundamental data which are critical for later process performance simulation work.

BR#1821

Cost Effective Mercury Emissions Control At The Newmont TS Power Plant

In early 2004, prior to issuance of the Clean Air Mercury Rule, Newmont Mining Corporation took a proactive stance in addressing mercury emissions when developing the greenfield 242 MW gross output TS Power Project in Nevada. The power plant air permit application proposed Powdered Activated Carbon (PAC) injection with brominated carbon to achieve low mercury emissions. In development of the final plant design, enhanced mercury removal and reduction of projected operating costs were achieved through the use of a cost-effective technology to maximize the co-benefit mercury control features of the FGD system through a sorbent enhancement halogen added to the coal fuel. This paper discusses the emissions control system design, presents supporting mercury emissions control performance data, reviews the initial system operating experience and presents the actual hourly cost savings of the combination of B&W PGG's MercPlus� (Hg+) technology with PAC injection upstream of the spray dryer absorber and fabric filter at this full-scale, operating power facility.

BR#1818

Commercialization of Oxy-Coal Combustion: Applying Results of a Large 30MW_th Pilot Project

After successful demonstration of oxy-combustion at B&W's 1.5 MW_th Small Boiler Simulator and very promising full-scale (300-500 MW_e) engineering studies, B&W and Air Liquide (AL) initiated a project to scale-up the technology at B&W's 100-million Btu/hr (30 MW_th) Clean Environment Development Facility. The paper describes the experimental demonstration results at 30 MW_th, and the next step in the demonstration of the B&W/AL oxy-combustion technology.

BR#1816

Slurry and Air Do Mix: Interim Results of WFGD Absorber Slurry Aeration Studies

Estimating the magnitude and distribution of air entrainment within the slurry of WFGD absorbers operating with forced oxidation is challenging. Detailed in this paper are the methodology and interim results of slurry aeration sampling in the absorber recirculation pump suction pipes at various operating units.

BR#1815

An Emissions Approach to SO₃ Mitigation

Total particulate emissions are being set near detection limits on new or revised power plant operating permits. Acid gas emissions, such as SO₃, which form particulate and make up a portion of total particulate, must be controlled to even lower values. This paper provides the results of investigations that have been performed and demonstrates achievable SO₃ emissions utilizing an emissions control system approach for a range of fuel sulfur contents.

BR#1814

SO₃ and Fine Particulate Mitigation at AES Deepwater

Upgrades to the AES Deepwater Unit have been completed to reduce NO_x, SO₃ and fine particulate emissions. The changes made on the system to achieve this reduction and the testing completed in 2007 and 2008 to confirm these reductions are outlined in this report. A comparison of similarities and differences between the AES Deepwater installation and a typical high sulfur coal-fired plant is also discussed.

BR#1809

Selective Use of Oxygen and In-Furnace Combustion Techniques for NO_x Reduction in Coal Burning Cyclone™ Boilers

A NO_x minimization strategy for coal-burning Cyclone boilers was developed that includes deep air staging, innovative oxygen use, reburning, and advanced combustion control enhancements. Computational fluid dynamics modeling was applied to refine and select the best arrangements and pilot-scale tests were conducted. Test results are reported in this paper.

BR#1808

30 MWt Clean Environment Development Oxy-Coal Combustion Test Program

B&W PGG in collaboration with Air Liquide have been working to develop and demonstrate oxy-coal combustion as a solution for carbon management for power generation. During 2007 and early 2008, B&W's existing 30 MWt CEDF was modified to operate in the oxy-coal combustion mode, and bituminous, subbituminous and lignite coals are being tested. This paper describes modifications to the CEDF and the oxy-coal process tested, summarizes the test results, and discusses operating experience.

BR#1807

Successful Implementation of Multi-Stage Gas Emissions Reductions at 1050 MWe Coleson Cove Generating Station Using Reburn, WFGD and WESP Technologies

This paper outlines NB Power's emissions reduction planning strategy for the Coleson Cove generating station. It also describes the design and performance characteristics of the combustion system with oil reburning plus the WFGD and WESP systems retrofitted at Coleson Cove generating station. Design features and performance achieved are included. (1601K)

BR#1806

Design and Performance Characteristics of a Reburning System at Coleson Cove Generating Station

This paper describes the design and performance characteristics of the oil reburning system retrofitted at Coleson Cove generating station. Design features and performance achieved during the performance tests are included. (1581K)

BR#1805

Rate-Based Simulation Model For Potential CO₂ Solvent-Performance Predication And Comparative Study With Baseline Solvent

B&W PGG's RSAT^™ process development activities have been focused on the selection of next generation CO₂ solvents with rapid absorption rate, high CO₂ capacity and low heat of absorption. Screening of different amine-based solvents is underway in our CO₂ Control Laboratory. Promising solvents identified will be subjected to a more extensive rate-based model development. In addition, with larger scale test data available for the promising solvents, the semi-empirical model will be upgraded from a solvent-screening tool to an easy-to-use design tool.

BR#1803

Catalytic Oxidation of Elemental Mercury at Low Temperatures

Catalyst-enhanced elemental mercury (Hg⁰) oxidation, when combined with a wet flue gas desulfurization system, provides a promising method to simultaneously control mercury and SO₂ emissions. The objective of this study was to investigate Hg⁰ oxidation by catalysts in typical conditions downstream of particulate collection devices. (1229K)

BR#1800

Minimizing NO_x with the Innovative AireJet™ Pulverized Coal Burner

A new, staged low-NO_x, pulverized coal burner named AireJet™ was developed with the aid of computational fluid mechanics modeling and tested at pilot scale. In the first commercial application of twelve AireJet burners in a 95 MW utility boiler that burns a Powder River Basin coal, the NO_x emissions averaged around 0.13 lb/MBtu and the LOI levels were less than 1%. (966K)

BR#1798

Control of Pulverized Coal Oxy-Combustion Systems

A potentially more efficient and less costly alternative to Integrated Gasification Combined Cycle (IGCC) plants under development for the purpose of greenhouse gas emissions is Oxy-coal combustion. In this concept, oxygen mixed with recycled flue gas replaces the normal combustion air resulting in a flue gas that consists primarily of CO2. The concentrated CO2 stream reduces the cost and energy requirements needed for its capture and sequestration. The control of the oxygen to the combustion process, recycled flue gas flow, and impact on other processes such as heat transfer in the boiler and gas stream constituents offers a unique set of control requirements which are discussed in this paper. (1160K)

BR#1797

Oxy-Combustion in Pulverized Coal Power Plants for Carbon Dioxide Concentration

Several options for concentrating and disposing of or utilizing carbon dioxide are under investigation by B&W and many others in the power generation industry. This paper briefly discusses the current economics and efficiency of three options (CO2 scrubbing, oxygen combustion and IGCC) as well as their key advantages and disadvantages, then focuses on oxygen combustion. It describes the oxygen combustion process and B&W's efforts to move forward with its commercial application.(1762K)

BR#1796

Performance Evaluation of Wet Electrostatic Precipitator at AES Deepwater

The wet electrostatic precipitators (WESPs) at AES Deepwater have been in commercial operation since the plant began operation in 1986. The WESP system was installed in response to local regulations for limiting the combined emissions of filterable particulates and sulfuric acid mist. In 1999 and 2005, AES, FLS and B&W developed and tested new designs for collector plates and electrodes to improve the WESP performance and reduce maintenance. This report presents the results of the testing. (2002K)

BR#1794

State of the Art of Oxy-Coal Combustion Technology for CO2 Control from Coal-Fired Boilers

The research and development of oxy-coal combustion for CO2 capture from coal-fired boilers has been the subject of numerous studies. Recently, B&W and Air Liquide, with sponsorship of the U.S. Department of Energy, have finished a pilot-scale evaluation of the technology at 1.5 MWth (5 MBtu/hr) using scale model commercial boiler equipment. This paper describes the research performed to date, future pilot-scale and scale-up of the technology to full-scale commercial operation. (1089K)

BR#1792

Comparisons of Environmental Quality, Performance and Economics of Clean Coal Technologies for Carbon Capture

An industry-standard financial model of a coal-fired power plant was used to compare the economic benefits and costs of new technologies for managing carbon. Selected results are reported, and conclusions drawn on directions for future research. (396K)

BR#1788

B&W’s AireJet™ Burner for Low NO_x Emissions

B&W has developed a truly new low NO_x burner for applications with overfire air which require very low emissions of NO_x and CO. The AireJet™ burner is different from other low NO_x burners in that a portion of the secondary air is introduced down the center axis of the burner, resulting in a high temperature reducing zone in the near burner region which enhances NO_x reduction. This paper discusses the extensive modeling, pilot-scale testing and first commercial application of this new burner. (3358K)

BR#1787

Role of Sulfides in the Sequestration of Mercury by Wet Scrubbers - Update

This paper updates BR-1770. See description below.(352K)

BR#1786

Fabric Filter Size Impacts on Mercury Control Using Activated Carbon Injection

This paper reports the results of an economic evaluation conducted for a coal-fired power plant. This study was conducted on 350 MW and 550 MW units that currently operate with hot-side electrostatic precipitators for flyash control. Economic evaluations are presented comparing conventionally sized and high velocity pulse jet fabric filters (PJFF) for particulate control. Depending on a given situation, a conventionally sized PJFF is shown to be the more cost effective control device while in other cases a high velocity PJFF is more cost effective.(251K)

BR#1785

WFGD Case Study - Maximizing SO₂ Removal by Retrofit with Dual Tray Technology

Michigan South Central Power Agency (MSCPA) operates a nominal 55 MW unit with a limestone forced oxidized WFGD system. The absorber was a tray tower with a single tray designed for 90% SO₂ removal and supplied by B&W. To increase SO₂ removal, MSCPA and B&W added a second tray in 2002 to take advantage of dual tray technology. SO₂ removal has been increased from 90% to 98% without the use of organic acids. This paper discusses the absorber design, operating parameters, results of the testing and system chemistry. (735K)

BR#1782

Applying Nonlinear Signal Analysis Techniques to Flame Scanner Signals to Improve Staging of Cyclone™ Boilers for NO_x Control

Cyclone^TM boiler owners continue to drive down NO_x emissions by increasingly sophisticated staging and air distribution schemes. Over the last 11 years under sponsorship of EPRI, the team of ORNL and B&W has developed pulverized coal burner diagnostic technology by applying nonlinear signal analysis techniques to flame scanner signals. The team has extended the technology to cyclones to facilitate deeper staging of the cyclones to reduce NO_x emissions. Development projects were conducted at the Alliant Energy Edgewater Units 3 and 4, and Ameren UE Sioux Unit 1. Nonlinear analysis statistics were correlated to upsets in cyclone operation resulting from poor air distribution in the burner and barrel. The team demonstrated that the lighter and main flame scanners can be used to independently guide adjustments to the burner and barrel. (1549K)

BR#1781

A System Approach to SO3 Mitigation

During the past decade, efforts to remove nitrogen oxides (NO_x) through the use of selective catalytic reduction (SCR) technology have resulted in increased sulfur trioxide (SO3) concentrations in the flue gas stream of utility boilers that fire fossil fuels or other specialty fuels. When a plant is considering the use of SO3 mitigation technologies, several areas of the boiler island and air quality control system need to be investigated to optimize the SO3 mitigation philosophy employed. A system approach to SO3 mitigation must be considered based on plant-specific conditions to reduce the overall cost of mitigation equipment. (224K)

BR#1780

Impact of Fabric Filter Media and SDA Operations on Multi-Pollutant Emissions

The impact on emissions and operating conditions of a change in fabric filter media at KCP&L's Hawthorn Unit 5 after 3.5 years of operation with the OEM-supplied bags to a new replacement bag has been reviewed using the unit's DCS data storage and retrieval system and the owner's periodic particulate emissions compliance test data. The new media has resulted in much lower filterable emissions than the initial OEM needle felt filter media but significantly higher condensable particulate emissions have been observed. The net result of the filter media change has been a fairly consistent level of total particulate emissions. (801K)

BR#1779

Flue Gas Treatment System Design Considerations for the City of Hamilton Oxygen Firing Demonstration

Unit 8 at City of Hamilton, Ohio, is a 25 MWe unit that is being converted for an oxygen-fired demonstration. One of the results of using oxygen rather than air is that the mass input to the combustion process is greatly reduced. Because of this, flue gas is recycled back to the boiler in sufficient quantity to increase the mass flow for heat transfer in the convection pass and to lower the adiabatic flame temperature in the boiler. Considerations for multi-pollutant removal are unique as is the question of whether that equipment should be located in the higher volume main flue gas recycle stream, in the product stream, or in the CO2 production system. This paper describes those considerations and how they have been applied for the City of Hamilton Oxygen Combustion Demonstration Project. (379K)

BR#1778

NO_x Reduction at Consumers Energy Dan E. Karn Generating Station

Consumers Energy approached B&W to engineer, fabricate and install SCR equipment at the Dan E. Karn generating facility, located in Essexville, Michigan. Karn 1 is a 255 MW CE tangential-fired boiler; Karn 2 is a 260 MW B&W wall-fired boiler. Both units are meeting Consumer Energy's NO_x reduction goal and have been in successful operation since the installation and startup of the SCRs. The success of the Karn project included a strong project team; a design that considered constructability, reliability and flexibility of the system; the use of proven technologies and new applications for existing technologies; and construction techniques that avoid unplanned interruption of ongoing plant operations. (476K)

BR#1772

Successful Implementation of Canada's First Coal Fired Post-Combustion NO_x Reduction Systems

This paper describes the successful design, installation and operation of Canada's first Selective Catalytic Reduction (SCR) systems for nitrogen oxides (NO_x) reduction installed at Ontario Power Generation's (OPG's) Lambton and Nanticoke coal fired power stations. OPG's initiative to reduce the emissions of NO_x from their coal fired stations led to the award of a contract to Babcock & Wilcox Canada (BWC) in June 2001 for the turnkey supply of SCRs for Lambton units 3 & 4 and Nanticoke units 7 & 8. B&W's scope included design, supply, construction and start-up of the SCRs, anhydrous ammonia systems, SCR support steel, pressure part modifications, platework modifications and reinforcement, control components and induced draft (ID) fan upgrades. All units have met initial performance guarantees and are in commercial operation. (303K)

BR#1771

NO_x Control for Utility Boiler Ozone Transport Rule Compliance

With sponsorship from the USDOE National Energy Technology Laboratory's Innovations for Existing Plants Program, B&W and Fuel Tech, Inc. teamed to evaluate an integrated solution for NO_x control. This system was comprised of B&W's DRB-4Z® low-NO_x pulverized coal (PC) burner technology and Fuel Tech's NO_xOUT®, a selective non-catalytic reduction (SNCR) technology, capable of meeting a target emission limit of 0.15 lb NO_x/10⁶ Btu with ammonia slip of less than 5 ppm. Commercial installations of B&W's low-NO_x burner, in combination with overfire air ports using PRB coal, have demonstrated a NO_x level of 0.15 to 0.2 lb/10⁶ Btu under staged combustion conditions. The proposed goal of the combustion system (no SNCR) for this project was a NO_x level at 0.15 lb/10⁶ Btu. The NO_x reduction goal for SNCR was 25% below the low-NO_x combustion emission levels. Therefore, overall NO_x emissions would approach a level of 0.11 lb/10⁶ Btu. (284K)

BR#1770

Role of Sulfides in the Sequestration of Mercury by Wet Scrubbers

Wet scrubber systems can provide cost-effective mercury emissions control. However, field- and bench-scale tests suggest that significant increases in elemental mercury (Hg⁰) concentration may occur across wet scrubbers. B&W has focused its research on finding solutions. During pilot-scale tests aimed at enhancing the mercury removal performance of wet FGD systems, B&W discovered the important role of sulfides on the sequestration of soluble ionic mercury (Hg²⁺) and was subsequently awarded two patents utilizing sulfide chemistry. A detailed mechanistic interpretation of the role of sulfide on the sequestration of Hg²⁺ is presented here with the aid of a commercial electrolytic equilibrium model. One of B&W's patented technologies that utilizes sodium hydrosulfide has been applied on several operating wet scrubbers to prevent re-emission of Hg⁰. The mechanistic information compiled by B&W has been used to further improve the performance of this technology in the field. (321K)

BR#1764

Pilot-Scale Evaluation of Coal Combustion in an Oxygen-Enriched Recycled Flue Gas

This paper describes a promising oxygen-based process (oxy-combustion process) enabling CO2 capture from coal-fired power plants. The technology involves replacement of the combustion air by pure oxygen diluted in recycled flue gases and will be applicable with minimal pressure-part modification to existing pulverized coal- fired boilers. The oxygen and recycled flue gas levels are adjusted to achieve flame and furnace temperatures compatible with today’s materials. Oxy-combustion performance using Powder River Basin coal with flue gas recirculation has been successfully demonstrated on a 5-million-Btu/hr pilot combustor. The results were compared to air-blown combustion. Various burner parameters were varied to obtain maximum benefits from the oxygen/flue gas configuration. The overall combustion characteristics were comparable to air firing. This paper describes the experimental results of oxy-combustion from the pilot-scale boiler simulator. Various aspect of oxy-combustion, such as flame shape, length, temperature, and emissivity, are discussed. Heat transfer from the flame in the boiler and in the convection pass will be reviewed. (511K)

BR#1763

Effects of SCR Catalyst and Wet FGD Additive on Speciation and Removal of Mercury within a Forced-Oxidized Limestone Scrubber

B&W conducted a full-scale mercury test program at Dominion Power’s 1,662-megawatt Mount Storm Power Station in Grant County, West Virginia. This is a bituminous-coal-fired power plant. The goals of this test program were to evaluate the impact of selective catalytic reduction (SCR) catalyst and B&W’s wet flue gas desulfurization (FGD) process (injection of a sulfur-donating compound) on the speciation and removal of mercury within a limestone forced-oxidized wet FGD system. Cormetech conducted a follow-on comparative study of the field data with its internally developed SCR mercury oxidation model, including agreement of the model predictions with the field data, projected unit performance curves, and identifying key operating and design parameters for accurate predictive capability. (500K)

BR#1762

Application of Wet Electrostatic Precipitators to Address Fine Particulate Emission Requirements from Fossil-Fueled Combustors

Application of wet electrostatic precipitators (WESPs) to boilers firing specialty fuels has been made on a limited basis over the past 30 years. However, with recent local/state requirements for new coal-fired plants using wet flue gas desulfurization (WFGD), the use of WESPs has been applied to limit total particulate emissions (including condensables and acid mist). Operating data from existing WESP installations demonstrate this technology’s ability to efficiently and reliably meet these stringent performance requirements. Discussion includes WESP history and development in this application, the generic configuration of WESPs commercially available, and various operational design philosophies that can be used. Aspects regarding installation of a WESP system for both original equipment and retrofit situations are described. Actual performance data of commercially operating WESP systems on this application are provided, as well as a discussion of future development activities that can further advance the technology. (1,454K)

BR#1757

Wet Flue Gas Desurfurization (WFGD) Slurry Spray Header Design System

B&W has developed a rule-driven design (RDD) computer application to speed the design of its wet flue gas desulfurization (WFGD) slurry spray header system including support steel. The application, written using the RuleStream RDD system, captures the talents of the many people involved in the spray system's design, including those involved in process engineering, design engineering technology, structural mechanics, and technical design. B&W's design standards and best practices are blended with fabricator capabilities and industry standards to form the application rules. Third-party software (for example CAESAR II) and proprietary computer programs are leveraged by the application courtesy of the RuleStream RDD architecture. The application seeks to automate the routine first 80% of the design, while providing interfaces to complete the design or explore "what-if" situations. Interfaces allow the evaluation of spray coverage, pipe velocities, pressure drop, physical clearances, weights, and stresses. The application generates drawings, a solid model, and a bill of material for fabrication. Using the application, repeatable, consistent results are achieved. There is a higher confidence in the generated design and a reduction in design cycle time. This saved time may be allocated to exploring alternative designs, pursuing fabricator quotes, performing contract level analysis in the proposal phase, or may be applied to other areas of the WFGD design. (1,160K)

BR#1754

Effects of SCR Catalyst, Ammonia Injection and Sodium Hydrosulfide on Speciation and Removal of Mercury within a Forced-Oxidized Limestone Scrubber

This paper details key test data on the individual and cumulative roles of SCR catalyst, ammonia injection, and sodium hydrosulfide (NaHS) on the speciation and removal of mercury within a forced-oxidized limestone scrubber. Testing was completed at Dominion Resources' 1,662-megawatt Mount Storm power station (firing a medium sulfur Eastern bituminous coal) in Grant County, West Virginia. Baseline mercury removal testing was completed under several scenarios. After baseline testing, sodium hydrosulfide was injected into the scrubber recirculation pumps to evaluate its impact on oxidation and re-emission of elemental mercury. Results indicated the effectiveness of B&W's patented injection technology (sodium hydrosulfide) in suppressing the re-emission of elemental mercury. Moreover, the presence of SCR catalyst significantly impacted the mercury speciation profile at the inlet of the wet scrubber, causing oxidation of the remaining elemental mercury. The oxidized mercury was effectively removed by the wet scrubber. (462K)

BR#1752

Development and Performance Data for Ammonia Injection and Gas Mixing Processes on SCR Applications^® System

The ammonia injection and gas mixing performance prior to an SCR reactor can be critical for high NO_x removal, low ammonia slip projects. The need for mixing becomes evident when examining the nature of distributions and the degree of excess reagent available. Establishing the degree of blending required is the first step. The second is providing a design that ensures the blend is achieved in an acceptably stable manner, a task that requires an understanding of ammonia injection and mixing fundamentals, as well as having experience with relevant practical application data. Both are presented in this paper. Coupled with development test data, field data makes possible the refinement of predictive performance formula and techniques. Ultimately, this facilitates early design optimization and confidence in performance.

BR#1743

Particulate Collection Options for Dry FGD Systems

This paper provides utility customers with insight regarding the various options, possible combinations, and types of particulate collection equipment that may optimize capital and operating costs when retrofitting DFGD systems or specifying DFGD configurations for new facilities. The paper includes plant descriptions for two (2) existing DFGD installations, and economic comparisons for alternative particulate control technologies. (630K)

BR#1742

The Past, Present and Future of Wet Electrostatic Precipitators in Power Plant Applications

This paper discusses the past application of WESP technology, recent experiences that pertain to the electric utility industry, and economic analyses of WESP application to address potential and future utility needs. The analyses compare the WESP to the alternative approach of sorbent injection to control acid mist emissions. (569K)

BR#1741

System Design Considerations for "Popcorn" Ash

The transport of popcorn ash and subsequent catalyst plugging in SCR systems is an emerging problem in the power industry. Modifications to both the economizer outlet hoppers and the ash removal systems can help address this problem. The outlet modifications are designed using three dimensional Computational Fluid Dynamics (CFD) models and a collection of popcorn ash aerodynamic property data determined through a series of laboratory experiments. This paper discusses CFD modeling of this issue, modifications to trap popcorn ash, the need for continuous ash removal, as well as the pros and cons of pneumatic vs. mechanical ash removal systems. (828K)

BR#1740

Coleson Cove Orimulsion Conversion Project

New Brunswick Power owns and operates the Coleson Cove thermal generating station. The station consists of three boiler units, each having a capacity of 350 MW. All three units are in the process of being converted from firing #6 residual oil to burn Orimulsion 400® fuel starting in the fall of 2004. Compliance with Environment Canada and local provincial emissions standards will be achieved by installing new state-of-the-art combustion systems and a flue gas desulfurization (FGD) system consisting of 2 x 525 MW absorber modules utilizing limestone forced oxidation (LSFO) technology. This paper describes the modifications required to convert the Coleson Cove station to Orimulsion firing, including upgrades to the B&W boilers and addition of the wet FGD system including integral wet precipitator. (824K)

BR#1738

Comparison of NO_x Emissions Reductions with PRB and Bituminous Coals in 900 MW Tangentially Fired Boilers

Three sister units having a peak generating capacity of approximately 900 MWe each were recently changed to reduce NO_x emissions. Unit 2 burns eastern bituminous coal while Units 3 and 4 burn Powder River Basin (PRB) sub-bituminous coal. A single level of separated overfire air ports using B&W's patented interlaced approach was installed on each unit with the goal of reducing NO_x emissions by 50% from baseline levels. This paper reports on the combustion system changes required to accomplish these reductions and compares baseline to current emissions and boiler performance. (390K)

BR#1737

Structural Considerations for SCR Retrofits

There are many engineering challenges involved with the retrofit of existing coal-fired power plants with SCR systems. Space for the addition of new equipment at an existing power plant is limited. The desire to close-couple the SCR to the boiler forces the designer to locate the SCR on structural steel above and between existing boiler components and equipment. This arrangement results in elaborate support structures and complex flue configurations. This paper provides insight into some of the many complexities and challenges the engineer should consider on large SCR retrofit systems. (651K)

BR#1734

Comparison of NO_x Emissions Reductions with PRB and Bituminous Coals on Tangentially-Fired Boilers

Two pairs of 500 and 900 MW eight corner, tangentially-fired "sister" units were modified to reduce their NO_x emissions. Of the two 500 MW units, one combusts eastern bituminous coal and the other a blend of bituminous and Powder River Basin (PRB) coals. Of the two 900 MW units, one burns eastern bituminous and the other burns PRB. B&W's patented interlaced overfire air system was installed on each unit with the goal of reducing NO_x emissions by more than 50% from pre-modification (baseline) levels. This paper reports on the combustion system modifications required to accomplish these reductions and compares baseline to post-modification emissions. (284K)

BR#1733

Integrated Design and Construction for Cost Effective SCR Projects

The retrofitting of power plants with NO_x control technologies is a cost-intensive undertaking facing many utilities. Key to controlling the economic impact to the utility is the effective execution of these projects. B&W has successfully designed and installed a number of SCR systems for both gas- and coal-fired boilers. The success of these installations is a direct result of the key decisions made during and the integrated techniques applied to the design and installation of these systems. The cost of the engineered equipment and the associated cost of installation are about equal in magnitude. Most system installations are retrofit projects. Optimizing the design of these unit-specific systems and the associated installation of these large components in typically restricted spaces during the minimum duration outage(s) involve a number of compromises and decisions. Typically these projects involve hundreds or thousands of tons of structural and plate steel and hundreds of thousands of manhours of field labor. The decisions and the process used to orchestrate them into an effective project will be discussed and placed into an economic perspective. The paper will highlight some of the key opportunities for controlling SCR project costs. (252K)

BR#1732

SCR System Operating Experience at AES Somerset

The AES Somerset Station in New York added a selective catalytic reduction (SCR) system to Unit 1 over the winter of 1998/1999 to further reduce NO_x emissions from this plant. This was the first large U.S. coal-fired SCR retrofit and was placed in service in 1999. This paper describes the Somerset SCR and provides an update to the operating experiences along with the alterations and improvements that have been incorporated into system operation and hardware. The paper includes the major lessons learned in the areas of ammonia vaporization, NO_x monitoring, and other operating issues. Outage inspection findings in the reactor, flues, and ammonia injection grid areas are noted, and catalyst performance activity results are provided. (373K)

BR#1728

Reliant Energy SCR Construction Implementation Plan

Reliant Energy has undertaken an aggressive construction schedule to complete 14 selective catalytic reduction (SCR) projects in the Houston area to meet State Implementation Plan (SIP) requirements that will be phased into place in April 2003 and April 2004. Babcock & Wilcox Construction Company (BWCC) was retained to construct 12 of these SCR systems. Integrating the construction plan into the overall engineering effort, Reliant has taken a strategic approach toward project completion that recognizes the availability of construction labor is critical to project success. This approach attempts to provide a predictable and stable workforce, build a learning curve, and maximize labor productivity. This paper will outline the strategy involved in the plan for completion, and key decision points. (367K)

BR#1726

B&W's Experience Reducing NO_x Emissions in Tangentially Fired Boilers - 2001 Update

B&W has recently completed modifications to the combustion systems for six tangential coal-fired utility boilers to reduce NO_x emissions consistent with regulatory requirements. In all cases, the modifications involved the application of staged combustion along the front and rear walls of the furnace in an interlaced injection pattern. Computational Fluid Dynamics (CFD) modeling was used to assist in the optimization of the designs, ensuring delivery of the required performance and minimizing installation costs. NO_x emission levels were reduced by more than 50% from baseline levels while, in all instances, thermal performance remained unchanged. This paper details the NO_x reduction approaches taken and the results of the modifications. (258K)

BR#1725

Benefits of SCR Design for Constructability

As it is defined today, constructability encompasses a wide variety of practices that when incorporated into a project can improve productivity and, in most cases, reduce costs or project risks. Given the recent trends in the availability of skilled labor to execute an SCR project, issues relating to productivity take on even greater importance. Recognizing that construction costs for SCR projects can exceed 50% of total project costs, and given that labor and equipment are significant cost components, it is prudent to design in a fashion that ensures the maximum efficiency of these valuable resources. (999K)

BR#1721

Integrated Environmental Control on the 21st Century's First New Coal-Fired Boiler

Following a February 1999 natural gas explosion at Kansas City Power and Light's (KCP&L) Hawthorn Power Station which destroyed the steam generator and associated equipment, a decision was quickly made to replace Unit #5 due to the need for power in the growing Kansas City metropolitan area. A new boiler burning Powder River Basin coal and accompanied with the necessary environmental control equipment was required to replace the damaged Unit 5. Current regulations required lower stack emissions and thus provided an opportunity to select the best available control technologies for the control of NOx, SO2, and particulate emissions. This paper describes the required emission limits and how the equipment was selected, designed, and installed to fulfill the needs for this project. (615K)

BR#1720

Design for Constructability - A Method for Reducing SCR Project Costs

Recognizing that construction costs for SCR projects can exceed 50% of the total project cost, and given that the resources (labor and heavy equipment) required to complete these projects are a significant component of that cost, it is prudent to design the project for "constructability" of the assembled components, ensuring maximum efficiency of these valuable resources. (973K)

BR#1719

Flue Gas Desulfurization Using Recycled Sodium Bicarbonate

This paper presents a breakthrough cost effective FGD technology using regenerated sodium bicarbonate/carbonate to remove SOx and NO_x, while producing valuable fertilizer co-products. Described is the advanced regeneration technology developed by AIRborne Technologies Inc. (ATI), combined with the commercial sodium scrubbing experience deployed by B&W, and the fertilizer marketing/distribution capability supplied by Potash Corporation. The development status of the technology, including historical results from AIRborne and the current program of the demonstration plant, is described in this paper. This timely examination will conclude with a study of a commercial installation identifying capital and operating costs of the B&W/AIRborne sodium carbonates system, as compared to a typical LSFO/SCR installation. (321K)

BR#1717

SCR Reactor Performance Profiling and Results Analysis

Increasingly stringent Selective Catalytic Reduction (SCR) system performance requirements for high nitrogen oxides (NOx) emission control with low ammonia slip demand proper distribution of flow, temperature, and reactant concentrations at the inlet to the catalyst bed. Analysis and comparison of reactor performance and outlet profiles regarding the extent of inlet parameter maldistribution is essential to the development of cost-effective design concepts and assessing their adequacy over operating ranges. This paper examines SCR reactor performance profiling as a means of predicting the consequences of inlet maldistribution and determining the theoretical and practical limitations of a system design. (301K)

BR#1716

Wet FGD Enhanced Mercury Control for Coal-Fired Utility Boilers

B&W and McDermott Technology Inc. (MTI) have had a continuing program over the past decade for optimizing mercury control technologies using conventional flue gas clean-up equipment, and addressing the design/commercialization issues of such control approaches. Results from testing conducted at B&W's Clean Environment Development Facility (CEDF) indicate the possibility of achieving 90% or greater mercury removal in a wet scrubber with the addition of a small amount of a proprietary reagent, with no adverse effects on scrubber operation or performance. Test results were encouraging enough that B&W and MTI, with funding assistance from the U.S. Department of Energy's (U.S. DOE) National Energy Technology Laboratory and the Ohio Coal Development Office (OCDO) within the Ohio Department of Development, is demonstrating this control technology at two utility power plants. This paper addresses the: (a) results of CEDF tests; (b) fate of mercury investigation findings; (c) results of mercury speciation tests; and (d) design/test plan for utility-scale demonstrations. (1,232K)

BR#1715

How Low Can We Go? Controlling Emissions in New Coal-Fired Power Plants

There is currently a demand for new coal-fired generation in the USA. The few coal-fired plants that have been permitted within the last ten years have been required to meet emission levels considerably less than NSPS. The realities of permitting a new coal-fired plant today will require low emissions. The need for ultra-high removal efficiency technologies for NOx, SO2, sulfuric acid mist, PM2.5, mercury, and particulate is here. There is also the potential need to lower CO2 emissions by utilizing more efficient steam cycles than have been used in this country to date. This paper examines in detail cost-effective advancements in known, proven emissions control technologies that achieve synergistic multi-pollutant capture and will briefly discuss steam cycle options to reduce CO2. (386K)

BR#1714

Lower NOx/Higher Efficiency Combustion Systems

Advanced low NOx burners are demonstrating significant improvements in performance beyond first generation low NOx burner results. These burners plug in to existing burner openings, facilitating use and reducing expense and outage time. Multi-air-zone OFA systems, optimized with computer modeling, enable further emission reductions. Results are presented showing 30 to 50% NOx reduction relative to high-quality first generation LNBs. This represents over 80% NOx reduction relative to uncontrolled sources with conventional burners. Unburned combustibles tend to increase with combustion modifications which reduce NOx. However, the new systems minimize this problem, without resorting to pulverizer upgrades. When pulverizer upgrades were simultaneously implemented, unburned combustibles were cut 80% along with major NOx reductions. Results are presented for 600 MW class units, substantiating the performance for a variety of coals, and verifying previous large-scale development work. (1,079K)

BR#1710

First Commercial Application of B&W's DRB-4Z^TM Ultra Low NO_x Coal-Fired Burner

Reliant Energy's W. A. Parish Generating Plant has taken a proactive approach to address ongoing state and federal guidelines regarding NOx emission reductions. In May 2000, the first commercial DRB-4Z™ low NOx burners with an interlaced overfire air system were placed into operation on Unit 6. Long-term pre-retrofit NO_x emissions were 0.40 lb/Mbtu. Performance tests conducted in the fall and winter of 1999 indicated pre-retrofit NOx levels of 0.35 lb/Mbtu. Post-retrofit NOx emissions are 0.17 lb/Mbtu or lower at full load. Actual NOx emission performance exceeded the guarantee level at full load. Achieving such low NOx emission levels on an opposed wall-fired boiler retrofit project, when firing Powder River Basin (PRB) coal, is a significant technical and operational milestone. (861K)

BR#1709

Flue Gas Desulfurization Technologies for Coal-fired Power Plants

The control of sulfur dioxide emissions from thermal power plants is examined in light of the recent advances made in developing commercial processes for this application. Beginning with a discussion of some of the more recent developments in the conventional wet and dry scrubbing technologies, the paper provides a description of the results of the recent full-scale demonstration projects conducted on the lower capital cost furnace and duct sorbent injection technologies - Limestone Injection Multistage Burner (LIMB) and Coolside, respectively. In addition, the results of large pilot-scale research and development activities on the related Limestone Injection Dry Scrubbing (LIDS) and SOx-NO_x-Rox Box (SNRB) processes are included. The paper concludes with a discussion of the economics of each of the processes based on U.S. installation. (334K)

BR#1707

Retrofitting Lime Spray Dryers at Public Service Company of Colorado

As part of its Denver-area Metro Emissions Reduction Project, Public Service of Colorado is installing lime spray dryers at its Valmont Unit 5 and its Cherokee station Units 3 and 4. The paper includes project background including cooperative agreements with various government and environmental concerns. The paper presents a technical description of the retrofits including ash system modifications, and lists expected performance for each unit. (220K)

BR#1703

Update of SCR Retrofit on a 675MW Boiler at AES Somerset

The AES Somerset coal-fired station near Buffalo, New York was retrofitted with a selective catalytic NO_x reduction (SCR) system in 1999. The SCR went into service in July 1999 and operated for the balance of the ozone season. It restarted on May 1, 2000. This paper describes project development, equipment design, construction, commissioning, optimization, catalyst design details and performance. (1070K)

BR#1702

Update of B&W’s Low NOx Burner Experience

B&W has installed low NO_x combustion equipment in more than 180 PC-fired steam generators representing over 78,000 MW of electrical generation. These include new boiler and retrofit applications covering a diverse range of coals and furnace geometries. This paper presents the results and experience gained from these installations. Selected units are considered in detail. Significant advancements in the area of low NO_x PC-fired burner design are presented. The paper also includes developments of a new gas-fired design which sharply reduces NO_x for gas, or gas-capable PC-fired burners. (380K)

BR#1700

B&W’s NOx Reduction Systems and Equipment at Moss Landing

California's Monterey Bay Unified Air Pollution Control District (MBUAPD) Rule 431 requires NO_x emissions to be less than 10 ppm by January 1, 2002 for Units 6 and 7 at Duke Energy's Moss Landing Power Plant near San Francisco. B&W developed a design in an alliance arrangement with the previous owner, Pacific Gas & Electric, to retrofit an SCR to Unit 7. Rule 431 was modified to slightly defer the SCR on Unit 7, replace the original burners on Units 6 and 7 with B&W's XCL-S™ low NO_x burners and install overfire air ports. The modified Rule 431 requires one unit to be at 10 ppm maximum NO_x with less than 10 ppm slip after December 31, 2000 and the second unit in compliance after December 31, 2001. (K)

BR#1699

Numerical Modeling for Design Optimization of SCR Applications

B&W has utilized numerical modeling to simulate fluid and combustion phenomena on commercial contracts for more than a decade. Verification of model predictions with actual field test results has provided valuable feedback for model development and refinement. Development and verification challenges exist when extending numerical modeling to include downstream SCR processes. Modeling approaches are undergoing continual improvement predicting component pressure drop, temperature and chemical specie distributions, mixing efficiencies, and reactor performance. This paper discusses numerical modeling as an increasingly valuable tool for SCR system design optimization efforts. (245K)

BR#1694

Recent SCR Retrofit Experience on Coal-Fired Boilers

B&W has retrofitted many coal-fired utility boilers with SCR NO_x control systems. The paper describes the integrated approach that can be used to reduce the overall cost of a NO_x control system. The paper also reviews how Computational Fluid Dynamics (CFD) and physical flow modeling have been used to develop the optimum design. Planning and construction techniques and their impact on project cost are reviewed. The retrofit at AES' Somerset Station Unit 1 is described and operating results are reviewed. (604K)

BR#1692

Dry Scrubber 20 Years Later

In 1979, Basin Electric Power Cooperative became involved with dry scrubbers for sulfur dioxide (SO₂) control as operating agent for the Laramie River Station (LRS), Wheatland, Wyoming. A contract was awarded to B&W in 1979 for the supply of the world's largest dry scrubber which would be installed on Unit 3 at LRS. The station was equipped with three B&W 586 MW pulverized coal-fired boilers. The first and second units were equipped with wet limestone scrubbers for SO₂ control. The decision to go with a dry scrubber on Unit 3 was economically driven as both the evaluated capital cost and operation cost were lower than that of the wet scrubber. The current operation is compared with the goals set for it in 1979. Included in this paper are a description of the system, listing of major modifications that have improved operation since the unit went commercial, a breakdown of current costs and a summary of system performance. (447K)

BR#1689

Advance, Low-Pressure–Drop, Tower Inlet Design

To remain competitive in the FGD market, B&W's Environmental Engineering has been developing technology to improve performance and reduce operating and capital costs of FGD systems. B&W, in cooperation with the McDermott Technology, Inc. (MTI) Research and Development Division continued an on-going program to improve FGD scrubber fluid mechanics. The goals of the program, which is in its seventh year, are to improve the product design and marketability by reducing scrubber cost and minimize the technical risks. For cost reduction, the program focuses on developing compact scrubber designs to reduce the material and fabrication costs. The technical risks are minimized by testing and evaluating new concepts and ideas in a one-eighth scale wet scrubber hydraulic model. The cumulative results of previous years' development efforts is an advanced scrubber design that is 20% smaller than the base-technology wet scrubber. The focus of the program this year is on testing a novel, low-pressure-drop tower inlet. Some of the results of this testing are summarized in this paper. (431K)

BR#1688

Computational Fluid Dynamics for Predicting Two-Phase Flow in a FGD Wet Scrubber

A numerical model has been developed to simulate the hydraulics of a flue-gas-desulfurization wet scrubber. This model can produce computer simulations of the complex physical processes present in a wet scrubber, complementing field and physical flow modeling data and guiding experimental testing to only the most promising configurations. This can lead to a faster, more thorough design process, ultimately providing the designer with more confidence in performance guarantees. Both two- and three-dimensional hydrodynamic simulations have been validated using pressure measurements and visual observations from a wet scrubber hydraulic test facility. Model development is ongoing, and enhancements will be added to include heat transfer and chemical reaction effects. (233K)

BR#1686

Low Cost Integrated NO_x Solutions – Evaluating Unit Economics

Deregulation of the power industry and tightening of NO_x regulations are creating challenges for electric utilities. Just as utilities are striving to drive down costs, further NO_x control requirements will result in increased capital and operating expenditures. A range of combustion technologies and post-combustion systems are available, and the key will be the optimization of their use to minimize costs. The paper covers the results from a B&W economic model used to optimize NO_x control options on a plant-specific basis. (284K)

BR#1685

Development of Mercury Emissions Control Technologies for the Power Industry

Concern over the difficulty of limiting the emission of trace amounts of hazardous air pollutants in large flue gas streams to meet potential environmental regulations has been a driving force for the development and characterization of control technologies for utility boilers. In cooperation with the U.S. Department of Energy and the Ohio Coal Development Office, Babcock & Wilcox/McDermott Technology, Inc. has been conducting the Advanced Emissions Control Development Program to investigate the formation and control of these emissions from coal combustion in the 10 MWe-equivalent Clean Environment Development Facility. This paper discusses results recently obtained on mercury speciation and removal, and their potential implications on the applicability of such conventional technologies as electrostatic precipitators, baghouses, sorbent injection, and wet flue gas desulfurization for cost-effective control of mercury emissions. (395K)

BR#1683

B&W's Advances on Cyclone NO_x Control Via Fuel and Air Staging Technologies

Recently, cyclone boiler owners have been installing NO_x control technologies in order to comply with the Title I and Title IV Clean Air Act Amendments (CAAA) of 1990. B&W has been working on the development and implementation of fuel staging (reburn) and air staging technologies. Gas reburn technology has been successfully retrofitted to three Eastman Kodak Company cyclone boilers located in Rochester, New York. From baseline NO_x emission levels, 50-75% reduction is achievable without any negative boiler operating consequences. In addition, B&W has successfully applied the air staging technology to numerous cyclone-equipped units firing a broad range of fuels. The largest of these boilers is TVA's 700 MWe Paradise Station Unit 1 where 50 to 70% NO_x reductions from baseline levels are being obtained while maintaining acceptable boiler operating conditions. The paper discusses these commercial applications of the gas reburn and air staged technology retrofits. A key new feature of the Kodak Gas Reburn retrofits is B&W's second generation gas burner design. Improved cyclone air flow measurement techniques at both Kodak and TVA will also be identified. (322K)

BR#1682

4 X 550 MWe Boiler Operating Experience at 0.15 lb/MBtu NO_x Emission Level Firing a Broad Range of Coals

B&W supplied four boilers and associated equipment for Taiwan Power Company's Taichung Power Station. These units are equipped with state-of-art NO_x reduction systems including DRB-XCL® coal/oil burners, Dual Air Zone NO_x Ports, and a Selective Catalytic Reduction (SCR) system. The units exclusively fire imported coal from Indonesia, South Africa, Australia, and the U.S. These coals exhibit a wide range of reactivity and ash characteristics, which significantly impact NO_x emissions and overall unit performance. This paper describes experience while firing a wide range of coals and lessons learned, which contribute to the successful operation of these units. (375K)

BR#1681

Wet Flue Gas Desulfurization Pilot Plant Testing of High Velocity Absorber Modules

In recent years the industry has been investigating the design and operation of Wet Flue Gas Desulfurization (WFGD) absorber modules with high gas velocities. Until 1994, conventional designs were set at 10-12 fps for vertical up-flow towers. However, beginning in the early 1990s, pilot testing and field demonstrations have been performed with velocities as high as 20 fps. The obvious advantage is a capital cost savings in the size of the absorber and in construction costs. However, high velocity operation has demonstrated that the absorption of SO₂ increases with increasing velocity and this leads to savings in pump power. This paper reviews B&W's pilot plant tests of High Velocity Absorber Modules (HiVAM). (134K)

BR#1680

Perspectives on Ammonia Injection and Gaseous Static Mixing in SCR Retrofit Applications

Achieving the stringent performance requirements of many SCR retrofit applications relies on a system design approach that allows for optimization. Options available in areas of ammonia injection and static mixing provide tools for the designer to improve process effectiveness. By reviewing the processes involved and the relative power consumption of each, optimization efforts can be enhanced. Product and performance optimization is achieved by the most appropriate application of the parts, in the manner that suits the particular retrofit site objectives. Integration know-how often provides the key to solving difficult process objectives. (133K)

BR#1679

Advances in Fine Grinding & Mill System Application in the FGD Industry

Being an integral part of the typical FGD system, the design and performance of the reagent preparation system will influence overall process effectiveness. In providing the most cost effective and energy efficient FGD system design, the options and advancements in size reduction processes urge consideration. Presented in this paper is an analysis of an attrition mill option, which can be used to demonstrate the opportunities available when applying comminution processes to the FGD industry. (157K)

BR#1678

Validation of Numerical Models of Flow Through SCR Units

Numerical modeling is used by B&W to support the design of products, including selective catalytic reduction (SCR) units. Traditionally, physical flow models have been used to ensure the proper flow properties entering the catalyst bed. Advances in computer processor speed and grid generation techniques now allow the flow and mixing properties in geometrically complex equipment to be numerically modeled economically. This paper discusses one such study. (820K)

BR#1676

Use of Seawater as Makeup Water for Wet Flue Gas Desulfurization Systems

Wet Flue Gas Desulfurization (WFGD) systems use considerable amounts of makeup water. In areas where fresh water is not readily available, this requires desalination of large quantities of water to provide makeup water to the WFGD system. It is possible to use seawater for makeup water in the WFGD systems with a considerable cost savings to the owner/operator. B&W has designed a WFGD system to use seawater as makeup water. This paper provides a brief description of the system and reviews performance, chemistry and materials of construction for this project. (133K)

BR#1671

Skewed Gas Flow Technology - A Method to Improve Precipitator Performance

The application of Skewed Gas Flow Technology (SGFT) by Stothert Engineering Ltd. has demonstrated that particulate emissions can be substantially reduced by departure from standards calling for uniform gas flow distribution. Controlled skewed flows implemented in precipitators serving approximately 7,000 MW of coal-fired electrical power generation plus installations in the pulp and paper industry have achieved reduction in particulate emissions from approximately 20% to over 70%. In most cases these emissions reductions have been achieved on installations previously using uniform gas flow standards. SGFT, utilizing inexpensive flow modifications, represents a major advancement in precipitator performance improvement technology. (83K)

BR#1667

San Juan Generating Station FGD Retrofit Project Update

This paper updates the flue gas desulfurization limestone conversion project at Public Service Company of New Mexico's San Juan plant. The project was designed and constructed under a teaming arrangement with the customer and utilized much of the existing equipment from the old FGD system. (67K)

BR#1666

KEPCO's First 5000 MW of Flue Gas Desulfurization

In 1995, Babcock & Wilcox (B&W) licensed wet limestone in-situ forced oxidation (LSFO) technology for flue gas desulfurization (FGD) to Hyundai Heavy Industries (HHI). B&W worked very closely with HHI during their initial bidding process, in both design and execution of the proposal. Subsequently, HHI was awarded two major flue gas desulfurization contracts by Korea Electric Power Company (KEPCO) in December of 1995. Specifically, HHI was awarded contracts to supply flue gas desulfurization systems for six (6) 500 MW units at the Hadong Power Plant and four (4) 500 MW units at the Taean Power Plant. This is the largest flue gas desulfurization system order ever placed in the world. For these first FGD contracts in Korea, B&W is supplying the process design and many of the engineered products. For future contracts, HHI expects to provide the entire plant design with only technical support from B&W. This paper presents the project execution methodology, including design, fabrication, and construction. (153K)

BR#1665

Development and Commercial Operating Experience of SCR deNO_x Catalysts for Wet-Bottom Coal-Fired Boilers

Selective Catalytic Reduction (SCR) of NO_x by ammonia (NH3) is now widely applied to reduce NO_x emissions from stationary sources. At present, hundreds of SCR systems are operating successfully in Japan, Europe, USA and several Asian countries. Babcock-Hitachi (BHK) and Babcock & Wilcox (B&W), as leading suppliers of SCR systems, have supplied more than 200 plants over the past 20 years. Among these plants, development and commercialization of SCR catalyst for wet-bottom boilers, such as cyclone furnaces and slag-tap boilers, was one of the more challenging experiences. The arsenic-resistant plate-type catalyst developed by BHK for this application has been successfully operating for nine years. (126K)

BR#1662

Flue Gas Desulfurization Technology for China

The extraordinary rate of development of the power industry in the Peoples Republic of China over the past decade brings with it an increasing concern for environmental protection. Between 1990 and 1995, new, coal-fired, thermal power plant capacity grew by approximately 40,000 MW. A projection of this installed capacity reaching 227,000 MW by 2010 is expected to result in coal use for electric power generation alone that is about four times greater than it was in 1990. With this greater utilization of coal, the need for emissions control has been recognized as an important part of developing an industry that will contribute to the further modernization of China in a way that minimizes the impact both on the health of the population and on the environment. English version: (22K) Chinese version: (197K)

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BR#1660

Lowest Cost Integrated NO_x Solutions for Title I and OTR Compliance

Deregulation of the power industry and tightening of NO_x regulations are creating challenges for electric utilities. Just as utilities are striving to drive down costs, further NO x control requirements will result in increased capital and operating expenditures. This paper briefly reviews the current regulatory status as well as the range of burner, overfire air port and SCR deNO x systems available. It concludes with the results from a B&W economic model used to optimized NO x control options on a plant-specific basis. (1176K)

BR#1657

Design Considerations for RDF-Fired Refuse Boilers

In spite of the many benefits, the combustion of refuse derived fuel (RDF) poses its own set of unique problems to a boiler designer in the areas of fuel handling, slagging, fouling, and corrosion which can be quite different from those encountered in a mass burn boiler system. This paper addresses the essential requirements of an effective RDF-fired boiler design. It is based on the experience gained from the operation of two 815 tonne/day (900 US ton/day) RDF-fired boilers located at the Palm Beach Resource Recovery Facility located in West Palm Beach, Florida, U.S.A. which has been in operation since 1989. (193K)

BR#1654

2200 MW SCR Installation on New Coal-Fired Project

This paper describes the application of high NO_x reduction SCR technology to the first large scale, coal-fired, multiple unit new installation. By integrating the SCR design into the initial boiler equipment arrangement and design, significant simplification of equipment arrangement resulted in project cost savings. The four 550 MW units at Taiwan Power's Taichung 5-8 Power Plant were installed, commissioned and tested demonstrating the low NO_x emission capabilities of SCR technology. (80K)

BR#1646

Selective Catalytic Reduction (SCR) Retrofit at San Diego Gas & Electric Company South Bay Generating Station

San Diego Gas & Electric (SDG&E) retrofitted South Bay Generating Station Unit 1 with selective catalytic reduction (SCR) technology to comply with San Diego County Air Pollution Control District (SDCAPCD) Rule 69 which regulates NO_x emissions. South Bay Unit 1 is a 154 MW gas/oil fired B&W radiant boiler of late 1950s vintage. The SCR project also included an aqueous ammonia storage and delivery system and SCR controls integrated in a recently installed Distributed Control System (DCS). This paper discusses significant aspects of the technical and economic evaluation, design, installation, and operational characteristics of this NO_x compliance project. A preview of SDG&E's compliance programs for South Bay and Encina Generating Station is also presented. (98K)

BR#1645

Wet FGD Forced Oxidation: A Review of Influencing Factors and a Comparison of Lance and Sparge Grid Air Introduction Methods

The dominant worldwide wet Flue Gas Desulfurization (FGD) design is the limestone forced-oxidized system, whereby limestone is utilized as the reagent and the process incorporates air injection to ensure a fully oxidized gypsum product. Two primary methods for typical wet limestone forced oxidized FGD systems are sparge grids and agitator air lances. Each have their own attributes which influence both suitability and cost effectiveness. This paper is a general discussion of these two system types. (97K)

BR#1643

Wet FGD System Materials Cost Update

This paper is an update of the report "Economic Comparison of Materials of Construction of Wet FGD Absorbers and Internals" which was presented at the 1991 EPRI/EPA/DOE symposium. An economic comparison of the materials used for fabrication of wet FGD spray towers are presented, with focus placed on the latest experience/developments with alloy, lined carbon steel, and lined concrete material selections. Costs for various materials of construction for such absorber components as spray headers, moisture separators, and gas distribution devices are also addressed. (138K)

BR#1641

Use of Stack Emissions to Control DBA Enhanced FGD Systems Burning Fuel Highly Variable in Sulfur Content

A fully automated control system that monitors stack SO₂ emissions and adjusts the scrubber's operating conditions accordingly is described in this paper. This new control concept was tested and implemented at the Ghent Generating Station. The use of the new control scheme resulted in optimization of reagent consumption and significant reduction in manual intervention by the FGD system operators. The new controls have been in operation since October, 1996. (622K)

BR#1640

New Perspective of Wet Scrubber Fluid Mechanics in an Advanced Tower Design

The need to understand the gas/liquid hydraulic interactions in a Wet Flue Gas Desulfurization (WFGD) absorber is important with the increased demand for compact high velocity scrubbing systems. This paper discusses those interactions between the gas and liquid phases in the absorption zone of the scrubber. Close study of the liquid and gas interaction in the scrubber showed that the relationships between the two fluids change with gas velocity. (100K)

BR#1625

Operational Results of a Low NO_x Burner Retrofit on a 200 MW Tri-Fuel Utility Boiler

This paper will discuss the low NO_x burner retrofit at Orange & Rockland Utilities' Lovett Generating Station Unit 5, located on the Hudson River in Tomkins Cove, New York, U.S.A. It was necessary to reduce NO_x emissions of the 200 MW tri-fuel utility boiler in order to comply with requirements set forth by the New York State Department of Environmental Conservation (NYSDEC). Unit 5 is a semi-outdoor, natural-circulation, divided-furnace, radiant-type steam generator originally supplied by B&W and placed in service in 1969. This unit has a pressurized divided furnace with a single-wall firing arrangement. The unit has a design pressure of 2250 psig, and the existing combustion equipment is capable of firing pulverized coal, natural gas or No. 6 fuel oil. When firing pulverized coal and oil, the main steam flow is 1,379,000 lbs/hr at 1000F. When firing only natural gas, the unit’s steam flow is 1,240,000 lbs/hr. Pre-retrofit NO_x emissions while firing pulverized coal were 0.62 lb/106 Btu, and unburned carbon (UBC) levels reached as high as 28.62%. It was Orange & Rockland’s objective to significantly reduce NO_x and UBC levels through the use of an in-furnace combustion process. (179K)

BR#1624

Air Pollution Control for Industrial Boiler Systems

A variety of constituents found in the products of combustion have been targeted for postcombustion control by national and local regulatory agencies. Primary among these are sulfur dioxide (SO₂), oxides of nitrogen (NO_x appearing mainly as NO), and particulate. Additional emphasis has recently been placed upon the control of hazardous air pollutants (HAPs or "air toxics") which are usually found in trace quantities. This paper specifically addresses technologies for the postcombustion control of these emissions. The control of NO_x by combustion system improvements and the control of SO₂ and NO_x through the implementation of fluidized bed combustion technology are covered extensively in References 1 and 2. In most cases, the postcombustion control technologies discussed here may be added to these two technologies to further reduce emissions. (184K)

BR#1613

Low NO_x Burner Retrofit Reduces NO_x by 50% On a 500 MW NSPS Boiler

This paper will present the goals, equipment selection and operating results of the low NO_x conversion of an NSPS boiler burning western subbituminous fuel. The subject unit is a nominal 500 MW Foster Wheeler boiler commissioned in 1981. The original firing equipment was designed in accordance with the New Source Performance Standards (NSPS) instituted in the 1970s. The original equipment included 24 scroll type burners in an opposed wall configuration. Eight overfire air ports were included with a port located above each column of burners. Each level of four burners is supplied with pulverized coal from one of six MBF-type pulverizers. The original and current fuel is a low sulfur subbituminous class C Powder River Basin coal. (119K)

BR#1607

Emission Control Technologies for Coal-Fired Power Plants

The control of sulfur dioxide emissions from thermal power plants is examined in light of the recent advances made in developing commercial processes for this application. Beginning with a discussion of some of the more recent developments in the conventional wet and dry scrubbing technologies, the paper provides a description of the results of the recent full-scale demonstration projects conducted on the lower capital cost furnace and duct sorbent injection technologies ‹ Limestone Injection Multistage Burner (LIMB) and Coolside, respectively. In addition, the results of large pilot-scale research and development activities on the related Limestone Injection Dry Scrubbing (LIDS) and SOx-NO_x-Rox Box (SNRB) processes are included. The paper concludes with a discussion of the economics of each of the processes. (224K)

BR#1604

Environmental Upgrades: Selected Case Histories

Some existing environmental equipment at utility and industrial plants is now 20 years old. Several can benefit from an upgrade in operations. This paper will discuss specific projects on wet FGD, dry FGD, and electrostatic precipitator systems operating in the U.S. What follows concentrates on the operational problems that led to the retrofit, and include economics. (40K)

BR#1595

SOx-NO_x-Rox-Box^TM Technology Review and Global Commercial Opportunities

The SOx-NO_x-Rox™ Box or SNRB™ process is a combined sulfur dioxide (SOx or SO₂), nitrogen oxides (NO_x) and particulate (Rox) emissions control technology developed by B&W in which high removal efficiencies for all three pollutants are achieved in a high-temperature baghouse. A 5 MWe equivalent demonstration of the technology co-sponsored by the U.S. Department of Energy (DOE), the Ohio Department of Development/Ohio Coal Development Office (OCDO), and the Electric Power Research Institute (EPRI) was completed in 1993 at the Ohio Edison R.E. Burger Plant. This unique, high-temperature baghouse/catalyst configuration provides for integrated particulate capture, SO₂ removal, and NO_x reduction. A brief overview of this technology is followed by a summary of operating results. Economic comparisons are presented, including a sensitivity analysis of major cost and performance factors which vary on a worldwide basis. (61K)