NOx Reduction of a 165 MW Wall-Fired Boiler Utilizing Air and Fuel Flow Measurement and Control

2002 ◽  
Author(s):  
Marion Cherry ◽  
Dave Earley ◽  
David Silzle
Keyword(s):  
Measurement System ◽  
Flow Measurement ◽  
Power Plants ◽  
Nox Reduction ◽  
Capital Requirements ◽  
Unburned Carbon ◽  
Front Wall ◽  
Future System ◽  
Reduction Strategies ◽  
Coal Flow

As a result of increasingly stringent emissions limitations being imposed on coal-fired power plants today, electric utilities are faced with having to make major compliance related modifications to their existing power plants. While many utilities have elected to implement expensive post-combustion NOx reduction programs on their largest generating units, infurnace NOx reduction offers a less expensive alternative suitable to any size boiler, to reduce NOx while also improving overall combustion. In-furnace NOx reduction strategies have proven that, when used with other less expensive approaches (Overfire air, fuel switching, and/or SNCR), levels less than 0.15 lb./MMBtu can be economically achieved. Furthermore, when implemented in conjunction with an expensive post-combustion SCR program, initial capital requirements and ongoing operating costs can be cut to save utilities millions of dollars. For the purpose of developing a system-wide NOx reduction strategy, Santee Cooper, a southeastern U.S. utility applied pulverized coal flow and individual burner airflow measurement systems to Unit 3 at its Jefferies Station, a 165MW, 16-burner front wall-fired boiler. The airflow measurement system, in service for many years, applied a well-proven averaging Pitot tube technology to measure individual burner secondary airflow. The coal flow measurement system utilized low energy microwaves to accurately measure coal density and coal velocity in individual coal pipes. The combination of these two systems provided the accurate measurements necessary for controlled manipulation of individual burner stoichiometries, giving the plant the ability to improve burner combustion, yielding a reduction in NOx levels approaching 20%. Optimized burner combustion also resulted in a leveling of the excess O2 profile, which will enable the plant to pursue further reductions in excess air as well as staged combustion, thus allowing for further NOx reductions in the future. How this program produced a significant NOx reduction will be presented in detail in this paper. The paper will also discuss the effects on excess O2, opacity, and unburned carbon. In addition, this program will allow for future system-wide planning with regard to possible SCR implementation.

Flow Measurement of Primary Air Containing Pulverized Coal with Simple Venturi Tube

2014 ◽  
Vol 986-987 ◽  
pp. 1506-1509
Author(s):  
Xing Sen Yang ◽  
Jing Yin
Keyword(s):  
Flow Measurement ◽  
Power Plants ◽  
Thermal Power ◽  
Pulverized Coal ◽  
Venturi Tube ◽  
Thermal Power Plants ◽  
Coal Particles ◽  
Safe State ◽  
Coal Flow ◽  
Remarkable Deviation

The flow measurement of primary air is very important for thermal power plants to maintain the safe state of operation. For direct firing pulverizing system, the measuring is essentially affected by pulverized coal particles. Abrasion and occlusion would bring great trouble to the measurement. Many measuring methods are invalid under that circumstance. Lots of efforts have been made to find appropriate ways to measure the flow of primary air containing pulverized coal. Venturi tube had been successfully used to measure the flow of air. If a venturi tube is used to measure the flow velocity of primary air, the differential pressure goes higher with the increase of the concentration of pulverized coal in the primary air. The neglect of the affection of pulverized coal on the measuring would result in remarkable deviation. With the aids of coal flow rate, a method of using venturi tube to measure the velocity of primary air containing pulverized coal was established. The affection of pulverized coal on flow measuring of primary air cannot be ignored.

A CFD Model Based Evaluation of Cost Effective NOx Reduction Strategies in a Roof-Fired Unit

2003 ◽  
Author(s):  
James Valentine ◽  
Marc Cremer ◽  
Kevin Davis ◽  
J. J. Letcavits ◽  
Scott Vierstra
Keyword(s):  
Fly Ash ◽  
Nox Reduction ◽  
Water Injection ◽  
Cost Effective ◽  
Cfd Modeling ◽  
Unburned Carbon ◽  
Cfd Model ◽  
Reduction Strategies ◽  
Nox Control ◽  
The Impact

To meet aggressive NOx reduction requirements, a range of NOx reduction strategies are currently available for application to pulverized coal fired furnaces. Utilities must assess the benefits and drawbacks of each viable NOx control technology to develop the best strategy for unit specific NOx control that fits within the utilities’ overall compliance plan. The installation of high capital and operating cost NOx reduction technologies, such as selective catalytic reduction, is cost prohibitive on many units. Lower cost technologies, although not capable of SCR level NOx reductions, can provide a more cost-effective approach and still achieve compliance over the fleet. This paper describes how computational fluid dynamic (CFD) modeling has been utilized by an experienced group of combustion engineers to evaluate and design cost effective NOx reduction strategies applied to a relatively unique PC fired unit, a B&W 150 MW roof-fired furnace. The unit fires bituminous coal through 10 multi-tip burners and is equipped with 10 NOx ports located below the burners. A baseline CFD model was first constructed and the predicted model results were compared with available data including NOx and CO emissions, as well as unburned carbon in fly ash. Upon completion of the baseline model, combustion alterations, including deeper staging, were evaluated. Specific burner adjustments were evaluated to allow for the deeper staging without significantly increasing unburned carbon in the fly ash, CO emissions, or near burner slagging. The CFD model was also utilized to evaluate the impact of water injection. AEP has previously utilized water injection to reduce peak combustion temperatures and thermal NOx formation rates in coal fired units for incremental NOx reductions. It is crucial that the NOx production zones in the downstream portion combustion field be identified, since these regions are most likely to produce NOx that will not be subsequently reduced prior to exiting the furnace. The CFD model was utilized to identify the most appropriate regions for water injection combined with the other combustion alterations. The results showed that NOx emissions could be reduced in this unit by approximately 37% from baseline full load emissions with no associated increase in unburned carbon in the fly ash or furnace exit CO. Burner alterations and water injection equipment based on the CFD model evaluation are currently being installed. Comparisons between the model predictions and the post retrofit performance will be provided.

Combustion Optimization for Increased Fuel Flexibility

2010 ◽  
Author(s):  
Bill Kirkenir ◽  
Dave Earley
Keyword(s):  
North Carolina ◽  
Flow Measurement ◽  
Nox Reduction ◽  
The Other ◽  
Efficiency Improvement ◽  
Fuel Flow ◽  
Fuel Flexibility ◽  
On Line ◽  
Coal Flow ◽  
Combustion Optimization

Progress Energy has incorporated on-line combustion optimization/tuning to lower LOI and eliminate furnace reducing atmospheres at several of their North Carolina Plants. The optimization projects utilized individual burner airflow measurement, continuous burner coal flow measurement and coal balancing valves to adjust burner air to fuel ratios. The DCS systems were modified to allow control of mass flow of air to each overfire air port as well as air to fuel ratio control of each burner. This was accomplished for the purpose of increasing Fuel Flexibility without impacting boiler and unit reliability. The objectives of the projects were to eliminating furnace reducing atmospheres and the resultant tube deterioration while improving fuel flexibility without negatively impacting boiler reliability. Other desired benefits included NOx reduction, decreased LOI, efficiency improvement and minimized boiler fouling. The focus of this paper is on the benefits and results experienced on the Asheville #2 unit. The furnace oxygen level through the combustion changes improved ∼334% while LOI decreased. The paper will also discuss the other improvements to the unit that were achieved by using the new air and fuel flow controls in the DCS. The paper will also outline additional improvements in the information available to unit operators, unit engineers and remote engineers.

scholarly journals Applications of oxygen for NOx control and CO2 capture in coal-fired power plants

2006 ◽  
Vol 10 (3) ◽  
pp. 119-142 ◽  
Author(s):  
Fabienne Châtel-Pélage ◽  
Rajani Varagani ◽  
Pavol Pranda ◽  
Nicolas Perrin ◽  
Hamid Farzan ◽  
...  
Keyword(s):  
Co2 Capture ◽  
Power Plants ◽  
Nox Reduction ◽  
Cost Effective ◽  
Pilot Scale ◽  
Capital Requirements ◽  
Pure Oxygen ◽  
Gas Treatment ◽  
Nox Control ◽  
The Cost

Two promising combustion modification approaches applicable to pulverized coal fired boilers are presented: "Oxygen-Enriched Combustion" (OEC) for NOx control and "Oxy-Combustion" (PC-OC) for CO2 capture. Oxygen-enriched air rather than air is used as an oxidizer in the OEC technology. Unlike flue gas treatment technologies, OEC directly impacts the NOx formation process by significantly reducing the conversion of coal bound nitrogen to NOx. Pilot-scale and full-scale tests have shown 20 to 30% NOx reduction from an optimized staged-air baseline. In addition to the overall cost competitiveness and the reduced capital requirements, other significant advantages of the O2-enriched technology vs. existing low NOx technologies are presented. The PC-OC technology is shown as a cost-effective technology for CO2 capture from existing or new coal-fired power plants. Pure oxygen diluted in recycled flue gases is used as an oxidizer. The process has been successfully demonstrated and extensively characterized at pilot-scale level (1.5 MWt). The tests have shown substantial benefits of the PC-OC technology, in terms of NOx reduction (60-70% from air-baseline), overall plant efficiency, etc. The cost effectiveness of this capture technology compared to competitive amine scrubbing technology was investigated. The cost of CO2 avoided was around $36/ton for the new PC-OC cases, about $48/ton on a retrofit PC-OC case, which is about 25 to 40% cheaper than the amine scrubbing system. Those numbers were calculated for sub-critical units and include the cost of CO2 compression up to 80 bar. .

scholarly journals Experimental Study and Design of Biomass Co-Firing in a Full-Scale Coal-Fired Furnace with Storage Pulverizing System

Agronomy ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 810
Author(s):  
Xuebin Wang ◽  
Zia Ur Rahman ◽  
Zhaomin Lv ◽  
Yiming Zhu ◽  
Renhui Ruan ◽  
...  
Keyword(s):  
Power Plants ◽  
Nox Reduction ◽  
Full Scale ◽  
Pollutant Emissions ◽  
Unburned Carbon ◽  
Renewable Energy Resources ◽  
Furnace Efficiency ◽  
Auto Ignition ◽  
Carbon Emissions Reduction ◽  
Biomass Particles

Co-firing coal and biomass in existing power plants facilitates influential advancement in the use of renewable energy resources and carbon emissions reduction. Biomass is intended as a CO2-zero net emission because, during its rise, it uses the same fraction of CO2 from the air as that released during its combustion. In addition, the content of nitrogen and sulfur in biomass is lower than in coal. Therefore, the emissions of NOx and SOx can be minimized by co-firing it with coal. In general, the effect of biomass direct co-firing on safety, pulverizing system performance, furnace efficiency, and NOx emission in full-scale furnaces is rarely studied. In this study, biomass direct co-firing was carried out in a 55 MW tangentially fired pulverized coal furnace. The effects of biomass co-firing on safety, the performance of the pulverizing system, furnace efficiency, and pollutant emissions (unburned carbon and NOx) are studied. The results show that the blending of biomass fuel with less than 20% of coal has no issue with respect to auto-ignition and safety. The performance of the pulverizing system is affected up to a certain limit due to the difficulty of grinding the biomass particles into required fineness. The biomass co-firing up to 20% is feasible, but greater than this percentage will severely affect the furnace efficiency. The co-firing of biomass enhanced the NOx reduction significantly and further improved the performance of the SNCR process. This study could provide guidance for the application of biomass co-firing in industrial furnaces.

The reactor research and test facility

2020 ◽  
pp. 69-79
Author(s):  
Andrey S. KIRILLOV ◽  
Aleksandr P. PYSHKO ◽  
Andrey A. ROMANENKO ◽  
Valery I. YARYGIN
Keyword(s):  
Measurement System ◽  
Nuclear Power ◽  
Power Plants ◽  
Test Facility ◽  
Physical Parameters ◽  
Pumping System ◽  
Current State ◽  
History Of ◽  
Special Measurement ◽  
Space Nuclear Power

The paper describes an overview of the history of development and the current state of JSC “SSC RF-IPPE” reactor research and test facility designed for assembly, research and full-scale life energy tests of space nuclear power plants with a thermionic reactor. The leading specialists involved in development and operation of this facility are represented. The most significant technological interfaces and upgrade operations carried out in the recent years are discussed. The authors consider the use of an oil-free pumping system as part of this facility during degassing and life testing. Proposed are up-to-date engineering solutions for development of the automated special measurement system designed to record NPP performance, including volt-ampere characteristics together with thermophysical and nuclear physical parameters of a ground prototype of the space nuclear power plant. Key words: reactor research and test facility, thermionic reactor, life energy tests, oil-free pumping system, automated special measurement system, volt-ampere characteristics.

"Recent Patents on the Triboelectrostatic Separation of Fly Ash"

2019 ◽  
Vol 13 ◽  
Author(s):  
Haisheng Li ◽  
Wenping Wang ◽  
Yinghua Chen ◽  
Xinxi Zhang ◽  
Chaoyong Li
Keyword(s):  
Fly Ash ◽  
Power Plants ◽  
High Efficiency ◽  
Separation Efficiency ◽  
High Reliability ◽  
Operating Conditions ◽  
Security Requirements ◽  
Unburned Carbon ◽  
Efficient Operation ◽  
Triboelectrostatic Separation

Background: The fly ash produced by coal-fired power plants is an industrial waste. The environmental pollution problems caused by fly ash have been widely of public environmental concern. As a waste of recoverable resources, it can be used in the field of building materials, agricultural fertilizers, environmental materials, new materials, etc. Unburned carbon content in fly ash has an influence on the performance of resource reuse products. Therefore, it is the key to remove unburned carbon from fly ash. As a physical method, triboelectrostatic separation technology has been widely used because of obvious advantages, such as high-efficiency, simple process, high reliability, without water resources consumption and secondary pollution. Objective: The related patents of fly ash triboelectrostatic separation had been reviewed. The structural characteristics and working principle of these patents are analyzed in detail. The results can provide some meaningful references for the improvement of separation efficiency and optimal design. Methods: Based on the comparative analysis for the latest patents related to fly ash triboelectrostatic separation, the future development is presented. Results: The patents focused on the charging efficiency and separation efficiency. Studies show that remarkable improvements have been achieved for the fly ash triboelectrostatic separation. Some patents have been used in industrial production. Conclusion: According to the current technology status, the researches related to process optimization and anti-interference ability will be beneficial to overcome the influence of operating conditions and complex environment, and meet system security requirements. The intelligent control can not only ensure the process continuity and stability, but also realize the efficient operation and management automatically. Meanwhile, the researchers should pay more attention to the resource utilization of fly ash processed by triboelectrostatic separation.

Real-time air flow measurement system for use by speech therapists

1991 ◽  
Vol 29 (1) ◽  
pp. 98-101 ◽  
Author(s):  
G. McCurrach ◽  
A. L. Evans ◽  
D. C. Smith ◽  
M. T. Gordon ◽  
M. B. D. Cooke
Keyword(s):  
Real Time ◽  
Measurement System ◽  
Flow Measurement ◽  
Air Flow ◽  
Speech Therapists

Invariant method for measuring wet gas flow rate

2021 ◽  
pp. 13-19
Author(s):  
Zhanat А. Dayev ◽  
Gulzhan E. Shopanova ◽  
Bakytgul А. Toksanbaeva
Keyword(s):  
Flow Rate ◽  
Measurement System ◽  
Flow Measurement ◽  
Gas Flow ◽  
Test Results ◽  
Invariant System ◽  
Rate Measurement ◽  
Gas Flow Rate ◽  
Flow Rate Measurement ◽  
Wet Gas

The article deals with one of the important tasks of modern flow measurement, which is related to the measurement of the flow rate and the amount of wet gas. This task becomes especially important when it becomes necessary to obtain information about the separate amount of the dry part of the gas that is contained in the form of a mixture in the wet gas stream. The paper presents the principle of operation and structure of the invariant system for measuring the flow rate of wet gas, which is based on the combined use of differential pressure flowmeters and Coriolis flowmeters. The operation of the invariant wet gas flow rate measurement system is based on the simultaneous application of the multichannel principle and the partial flow measurement method. Coriolis flowmeters and the differential pressure flowmeter are used as the main elements of the system. The proposed measurement system does not offer applications for gases with abundant drip humidity. The article provides information about the test results of the proposed invariant system. The estimation of the metrological characteristics of the invariant system when measuring the flow rate of wet gas is given. The obtained test results of the invariant wet gas flow rate measurement system are relevant for natural gas production, transportation, and storage facilities.

scholarly journals Use of Ash-and-Slag Wastes after Burning of Fine-Dispersed Coal-Washing Wastes

2018 ◽  
Vol 41 ◽  
pp. 01042
Author(s):  
Vasilii Murko ◽  
Veniamin Khyamyalyainen ◽  
Marina Baranova
Keyword(s):  
Power Plants ◽  
Building Materials ◽  
Negative Impact ◽  
Mineralogical Composition ◽  
Unburned Carbon ◽  
Crushed Rock ◽  
Low Carbon ◽  
Technological Parameters ◽  
Coal Fuel ◽  
Granulated Slag

Effective utilization of ash-and-slag waste generated by coalfired power plants can help significantly to reduce the negative impact on the environment and improve their economic performance. Studies have been made of the mineralogical composition of ash-and-slag wastes obtained after the combustion of water-coal fuel based on fine-dispersed coal-washing waste (filter cake) in a specially designed boiler with a vortex combustion system. The possibility of effective use of ash-and-slag wastes for the production of building materials, primarily mortar mixes, widely used for mining works on mine openings, laying the worked out space, etc. (high content of silicon oxide and aluminum oxide is combined with a low carbon content in other words a negligible unburned carbon loss). The optimum percentage ratio of the initial components of the filling mixture based on ash-and-slag wastes and crushed rock (granulated slag) has been established. The results of experimental tests of hardening tabs on the strength under uniaxial compression are presented. It has been established that a sample containing 18% of ash-and-slag wastes, 33% of a granulated slag and 19% of cement, corresponds to the required technological parameters for the strength and cement content.

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