NOx Control for Stationary Sources and Utility Applications

2003 ◽  
Author(s):  
Thomas F. McGowan
Keyword(s):  
Gas Turbines ◽  
Cost Effective ◽  
Nox Formation ◽  
Industrial Plants ◽  
Clean Air ◽  
Corporate Goals ◽  
Ozone Transport ◽  
Electric Generation ◽  
Nox Control ◽  
Stationary Sources

NOx control is coming to electric generation utilities and industrial plants in a big way. Federal regulations, ozone non-attainment areas, ozone “transport regions,” acid rain provisions of the Clean Air Act, and corporate goals for emission reductions are all motivators. This paper explores regulations, the chemistry of NOx formation, and practical and cost-effective ways to reduce NOx at its source, as well as “end-of-pipe” methods for the major targets: coal fired boilers, gas and oil boilers, and gas turbines.

CFD Modeling of NOx Reduction Technologies in Utility Boilers

2000 ◽  
Author(s):  
Marc A. Cremer ◽  
Bradley R. Adams ◽  
David H. Wang ◽  
Michael P. Heap
Keyword(s):  
Nox Reduction ◽  
Electric Utility ◽  
Cfd Modeling ◽  
Nox Formation ◽  
Modeling Tools ◽  
Chemical Mechanisms ◽  
Utility Boilers ◽  
Clean Air ◽  
Nox Control ◽  
Selective Noncatalytic Reduction

Abstract This paper discusses the development and application of CFD modeling tools that have been utilized to assess and design NOx reduction systems that are currently being evaluated by the electric utility industry. Stringent limits on NOx emissions have been imposed by the Clean Air Act Amendments, and a number of NOx reduction technologies are available to help meet these limits including selective noncatalytic reduction (SNCR) and reburning, as well as various combinations of these. This paper discusses the development and implementation of global and reduced chemical mechanisms for NOx formation/destruction into a comprehensive CFD code so that these various options for NOx control can be evaluated. Also, some examples showing the application of these tools to full-scale utility boilers utilizing low-NOx burners, air staging, and SNCR are presented.

Utilization of the MK Combustion Optimization System™ to Maximize Combustion Efficiency in an Environment-First Fashion

2004 ◽  
Author(s):  
David Krzysik
Keyword(s):  
Fine Particles ◽  
Effective Means ◽  
Nox Reduction ◽  
Cost Effective ◽  
Combustion Efficiency ◽  
Contributing Factors ◽  
Nox Formation ◽  
Trade Offs ◽  
Clean Air ◽  
Combustion Optimization

Nitrogen oxide (NOx) emissions discharged into the atmosphere from fossil fuel combustion prove to have adverse effects on the environment and human health. Contributing factors include the formation of acid rain, ozone, degradation of visibility, and inhalable fine particles. In addressing these problems, environmental regulations are becoming more stringent on electric utilities. Low NOx burner (LNB) technology was developed to provide a cost-effective means of complying with the NOx Reduction Program under Title IV of the Clean Air Act Amendments (CAAA) of 1990. Prior to LNB technology, standard burners were designed to rapidly mix the fuel and oxidant, producing high combustion efficiency and large quantities of NOx. Limiting the reaction rate at which the air and fuel mix, particularly during the early stages of combustion, can effectively control NOx formation; however, this rate limitation tends to diminish combustion efficiency and proves to be the compromise of LNB technology. Controlling one aspect or the other can be intuitively easy, but controlling both is challenging and trade-offs are necessary. Identifying a happy medium between the standards of yesterday and today is necessary in the optimization of coal-fired combustion. The ultimate effect will improve commercial availability in an environment-first fashion.

Analysis of the Mixing and Emission Characteristics in a Model Combustor

2018 ◽  
Author(s):  
Shan Li ◽  
Shanshan Zhang ◽  
Lingyun Hou ◽  
Zhuyin Ren
Keyword(s):  
Gas Turbines ◽  
Schmidt Number ◽  
Numerical Study ◽  
Flame Temperature ◽  
Scalar Dissipation ◽  
Mixing Process ◽  
Nox Formation ◽  
Turbulent Schmidt Number ◽  
Wide Range ◽  
Air Mixing

Modern gas turbines in power systems employ lean premixed combustion to lower flame temperature and thus achieve low NOx emissions. The fuel/air mixing process and its impacts on emissions are of paramount importance to combustor performance. In this study, the mixing process in a methane-fired model combustor was studied through an integrated experimental and numerical study. The experimental results show that at the dump location, the time-averaged fuel/air unmixedness is less than 10% over a wide range of testing conditions, demonstrating the good mixing performance of the specific premixer on the time-averaged level. A study of the effects of turbulent Schmidt number on the unmixedness prediction shows that for the complex flow field involved, it is challenging for Reynolds-Averaged Navier-Stokes (RANS) simulations with constant turbulent Schmidt number to accurately predict the mixing process throughout the combustor. Further analysis reveals that the production and scalar dissipation are the key physical processes controlling the fuel/air mixing. Finally, the NOx formation in this model combustor was analyzed and modelled through a flamelet-based approach, in which NOx formation is characterized through flame-front NOx and its post-flame formation rate obtained from one-dimensional laminar premixed flames. The effect of fuel/air unmixedness on NOx formation is accounted for through the presumed probability density functions (PDF) of mixture fraction. Results show that the measured NOx in the model combustor are bounded by the model predictions with the fuel/air unmixedness being 3% and 5% of the maximum unmixedness. In the context of RANS, the accuracy in NOx prediction depends on the unmixedness prediction which is sensitive to turbulent Schmidt number.

scholarly journals Fugitive Methane Emission Reduction Using Gas Turbines

1998 ◽  
Author(s):  
Todd Parker
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Cost Effective ◽  
Process Gas ◽  
Natural Gas Transmission ◽  
Air Intake ◽  
Lean Fuel ◽  
Gas Seals ◽  
Turbo Compressor ◽  
Many Sources

Natural gas transmission systems have many sources of fugitive methane emissions that have been difficult to eliminate. This paper discusses an option for dealing with one such source for operations using turbo-compressor units fitted with dry gas seals. Dry seals rely on a small leakage of process gas to maintain the differential pressure of the process against the atmosphere. The seal leakage ultimately results in waste gas that is emitted to the atmosphere through the primary vent. A simple, cost effective, emission disposal mechanism for this application is to vent the seal gas into the gas turbine’s air intake. Explosion hazards are not created by the resultant ultra-lean fuel/air mixture, and once this mixture reaches the combustion chamber, where sufficient fuel is added to create a flammable mixture, significant oxidation of the seal vent gas is realized. Background of the relevant processes is discussed as well as a review of field test data. Similar applications have been reported [1] for the more generalized purpose of Volatile Organic Compound (VOC) destruction using specialized gas turbine combustor designs. As described herein, existing production gas turbine combustors are quite effective at fugitive methane destruction without specialized combustor designs.

ANN-Based System Identification, Modelling and Control of Gas Turbines – A Review

2012 ◽  
Vol 622-623 ◽  
pp. 611-617 ◽  
Author(s):  
Hamid Asgari ◽  
Xiao Qi Chen ◽  
Mohammad Bagher Menhaj ◽  
Raazesh Sainudiin
Keyword(s):  
System Identification ◽  
Gas Turbines ◽  
Experimental System ◽  
Vital Role ◽  
Nonlinear Behaviour ◽  
Industrial Plants ◽  
Research Activities ◽  
Significant Research ◽  
Artificial Neural Network Ann ◽  
And Control

Gas Turbines (GTs) are the beating heart of nearly all industrial plants and specifically play a vital role in oil and power industries. Significant research activities have been carried out to discover accurate dynamics and to approach to the optimal operational point of these systems. A variety of analytical and experimental system identification methods, models and control systems has been investigated so far for gas turbines. Artificial neural network (ANN) has been recognized as one of the successful approaches that can disclose nonlinear behaviour of such complicated systems. This paper briefly reviews major ANN-based research activities in the field of system identification, modelling and control of gas turbines. It can be used as a reference for those who are interested to work and study in this area.

Lowering Equivalence Ratio Limit for Stable Combustion in Gas Turbines by Injection of Free Radicals

2011 ◽  
Author(s):  
Yeshayahou Levy ◽  
Vladimir Erenburg ◽  
Valery Sherbaum ◽  
Vitali Ovcharenko ◽  
Leonid Rosentsvit ◽  
...  
Keyword(s):  
Free Radicals ◽  
Gas Turbines ◽  
Equivalence Ratio ◽  
Nox Reduction ◽  
Combustion Process ◽  
Combustion Regime ◽  
Combustion Stability ◽  
Nox Formation ◽  
Stable Combustion ◽  
Lean Premixed

Lean premixed combustion is one of the widely used methods for NOx reduction in gas turbines (GT). When this method is used combustion takes place under low Equivalence Ratio (ER) and at relatively low combustion temperature. While reducing temperature decreases NOx formation, lowering temperature reduces the reaction rate of the hydrocarbon–oxygen reactions and deteriorates combustion stability. The objective of the present work was to study the possibility to decrease the lower limit of the stable combustion regime by the injection of free radicals into the combustion zone. A lean premixed gaseous combustor was designed to include a circumferential concentric pilot flame. The pilot combustor operates under rich fuel to air ratio, therefore it generates a significant amount of reactive radicals. The experiments as well as CFD and CHEMKIN simulations showed that despite of the high temperatures obtained in the vicinity of the pilot ring, the radicals’ injection from the pilot combustor has the potential to lower the limit of the global ER (and temperatures) while maintaining stable combustion. Spectrometric measurements along the combustor showed that the fuel-rich pilot flame generates free radicals that augment combustion stability. In order to study the relevant mechanisms responsible for combustion stabilization, CHEMKIN simulations were performed. The developed chemical network model took into account some of the basic parameters of the combustion process: ER, residence time, and the distribution of the reactances along the combustor. The CHEMKIN simulations showed satisfactory agreement with experimental results.

Development of a Case Vibration Measurement System for the DC-990 Gas Turbine

1984 ◽  
Vol 106 (4) ◽  
pp. 935-939
Author(s):  
H. A. Kidd
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Cost Effective ◽  
Industrial Applications ◽  
Vibration Monitoring ◽  
Vibration Measurement ◽  
Monitoring Systems ◽  
Development Programs ◽  
Field Service ◽  
Service Staff

The continued use of gas turbines in industrial applications and increased customer desires for trend analysis has led gas turbine suppliers to develop sophisticated, reliable, cost-effective vibration monitoring systems. This paper discusses the application of case vibration monitoring systems and the design criteria for each component. Engine installation, transducer mounting brackets, types of transducers, interconnecting cables and connectors, charge amplifiers, and signal conditioning and monitoring are considered. Examples are given of the benefits experienced with the final system in several of Dresser Clark’s engine development programs, by manufacturing and production testing, and by Dresser’s field service staff.

Remote Condition Monitoring of a Peaking Gas Turbine

1991 ◽  
Author(s):  
Ralph E. Harris ◽  
Harold R. Simmons ◽  
Anthony J. Smalley ◽  
Richard M. Baldwin ◽  
George Quentin
Keyword(s):  
Gas Turbine ◽  
Condition Monitoring ◽  
Gas Turbines ◽  
Vibration Amplitude ◽  
Thermal Stabilization ◽  
Cost Effective ◽  
System Structure ◽  
Start Up ◽  
Data Content ◽  
Software And Hardware

This paper illustrates how software and hardware for telecommunications and data acquisition enable cost-effective monitoring of peaking gas turbines using personal computers. It describes the design and evaluation of a system which transmits data from each start-up and shutdown over 1,500 miles to a monitoring computer. It presents system structure, interfaces, data content, and management. The system captures transient sequences of acceleration, synchronization, loading, thermal stabilization, steady operation, shutdown and cooldown; it yields coherent sets of speed, load, temperature, journal eccentricity, vibration amplitude, and phase at intervals appropriately spaced in time and speed. The data may be used to characterize and identify operational problems.

Heat Recovery Steam Generator Design for a Graz Cycle Prototype Power Plant for CO2 Capture

2004 ◽  
Author(s):  
I. Giglmayr ◽  
J. Paul ◽  
W. Sanz
Keyword(s):  
Steam Generator ◽  
Gas Turbines ◽  
Heat Recovery ◽  
Fossil Fuels ◽  
Cost Effective ◽  
Pure Oxygen ◽  
Exhaust Gas ◽  
Heat Recovery Steam Generator ◽  
University Of Technology ◽  
Generator Design

The introduction of closed cycle gas turbines with their capability of retaining combustion generated CO2 can offer a valuable contribution to the Kyoto goal and to future power generation. Therefore, research and development at Graz University of Technology has lead to the GRAZ CYCLE, a zero emission power cycle of highest efficiency. The GRAZ CYCLE is still on a theoretical level, first tests with the turbo-machinery equipment were performed. In the GRAZ CYCLE fossil fuels are burned with pure oxygen which enables a cost-effective separation of the combustion generated CO2 by condensation. Cycle efficiencies as high as 63% can be reached. Taking the efforts for the oxygen supply into account the efficiency is reduced to 55% [1]. This work presents a further step towards a GRAZ CYCLE prototype plant, with special emphasis on the layout and design of the heat recovery steam generator (HRSG). The hot exhaust gas of the turbine consists mainly of CO2 and H2O. This exhaust gas causes higher demands on the HRSG. A faster corrosion of the heat exchangers and the recirculation of the cycle fluid have to be considered. Based on the design of conventional HRSGs, the necessary adaptations are discussed and economically evaluated.

Design and Maintenance Issues of Being Able to Repair Marine Gas Turbines Without Removal From the Ship

2019 ◽  
Author(s):  
Bruce D. Thompson ◽  
John J. Hartranft ◽  
Dan Groghan
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Electrical Power ◽  
Corrosion Damage ◽  
Cost Effective ◽  
Air Filtration ◽  
Expected Time ◽  
Engine Vibration ◽  
Engine Design ◽  
Engine Maintenance

Abstract When the concept of aircraft derivative marine gas turbines were originally proposed, one of the selling points was the engine was going to be easy to remove and replace thereby minimizing the operational impact on the ship. Anticipated Mean Time Between Removal (MTBR) of these engines was expected to be approximately 3000 hours, due mostly to turbine corrosion damage. This drove the design and construction of elaborate removal routes into the engine intakes; the expected time to remove and replace the engine was expected to be less than five days. However, when the first USN gas turbine destroyers started operating, it was discovered that turbine corrosion damage was not the problem that drove engine maintenance. The issues that drove engine maintenance were the accessories, the compressor, combustors and engine vibration. Turbine corrosion was discovered to be a longer term affect. This was primarily due to the turbine blade and vane coatings used and intake air filtration. This paper discusses how engine design, tooling development, maintenance procedure development and engine design improvements all contributed to extending the MTBR of USN propulsion and electrical power generation gas turbines on the DD 963, CG 47, DDG 51 and FFG 7 classes to greater than 20,000 hours. The ability to remove the gas turbine rapidly or in most cases repair the engine in-place has given the USN great maintenance flexibility, been very cost effective and not impacted operational readiness.

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