bluuebunny/crossref_metadata_2025 huggingface dataset:
A Comprehensive Approach to NOx Reduction Without Low NOx Burners
Authors: Storm Stephen K. , Moss Maureen M.
Published: October 2008

The traditional approach to reduce NOx has been to retrofit and install commercially available “plug-in” Low NOx burners. Typically, these use a combination of internal staging and are often used in conjunction with over-fire air to create off-stochiometric or staged combustion. That is, the complete combustion of the fuel occurs in several stages. Often, well designed Low NOx burners are installed without a comprehensive systems approach. The typical challenges associated with staged combustion are related to the fact that burner performance must be nearly perfect to complete combustion within the available residence time of the furnace. Specifically, attention to airflow measurement and control by use of reliable & repeatable venturis and with pulverizer performance optimization. To maintain or improve this unit’s excellent reliability, a focus on optimizing the inputs and completing the combustion prior to the furnace exit was implemented. The goals of this project were as follows: 1. NOx Reduction from .78lb/mmBtu(full load) – 1.0#/mmBtu(low load) to less than 0.36 lb/mmBtu; 2. Flyash Carbon Content less than 10%; 3. Combustion Optimization; 4. Minimal slagging; 5. Maintain the same as baseline FEGT or reduce FEGT; 6. Maximum Load Capability; 7. Maximum Fuel Flexibility; 8. Complete the project at the lowest cost per kW possible (with the best results). All of the goals were accomplished. The technical success of this project is the results of applying a systematic and comprehensive approach beginning with raw coal feed to the pulverizers. The benefits of this total combustion optimization project is that later when additional NOx reductions are required, they can be added as a complimentary change to the present system. For example, if this unit is later equipped with SNCR or SCR, reduced rates of ammonia will be required, there will be reduced “popcorn ash” production, and less SCR catalyst wear and overall unit improved performance and reliability.
Volume, Temperature and Location of Smoke in Fires
Authors: Lilley David G.
Published: October 2008

Fires can be a major problem when they occur in industrial power generation facilities. The volume, temperature, composition of combustion product species, and location of smoke produced in fires may be calculated. A computer code is described that accomplishes this. Smoke cooling and volume changes are included from radiation heat loss from the fire, cooler air entrainment into the plume (column of smoke products above the fire), and conduction heat loss through the ceiling. Any hydrocarbon fuel, also possibly containing oxygen, is permitted as the fuel, and it burns with a specified equivalence ratio with air or oxygen. If in “air”, the volume fraction of oxygen may be specified. For simplicity and because most applications are to fires burning in air, dissociation is omitted since this is rather minimal at the temperatures encountered. The mathematical basis and algorithms are presented, together with the methodology of the Excel/VBA computer code that permits easy input and output, and results show the versatility of the code.
High-Temperature and High-Pressure Steam Flow Through a Steam Turbine Bypass Valve Line
Authors: Amano R. S.
Published: October 2008

The objective of the present study is to investigate the steam flow behavior through the high-pressure turbine bypass valve. Efforts have mainly been directed at investigating the process of steam flow and property variations aforementioned bypass valve as well as to obtain correlations between the flow rate and the valve opening ratio. Modeling of the high-pressure turbulent steam flow was performed on a three-dimensional non-staggered (co-located) grid system by employing the finite volume method and by solving the three-dimensional, turbulent, compressible Navier-Stokes, and energy equations. Through this research, numerous data have been acquired and analyzed. These efforts enable us to obtain a correlation data set for the flow rate coefficient as a function of valve opening. One of the significant accomplishments is to use the model presented here for further improve a design of a turbine bypass flow valve.
Reduce Fuel Costs and NOx Emissions by Controlling Excess Oxygen in the Firebox
Authors: Lang Gary A. , Knight Brien , Barker Paul
Published: October 2008

The real time, in-situ measurement of excess oxygen and temperature in the radiant heat zone of a boiler or furnace provides a window for viewing combustion conditions closest to the source. Excess oxygen and temperature measurements, taken at strategic sample points around the firebox, provide timely information for optimal trim control of the combustion process. With fuel costs skyrocketing and a focus on reducing NOx emissions, it is essential that the excess oxygen measurement be fast and accurate. Commercially available in-situ, high temperature oxygen sensors have the potential to solve combustion control and burner management problems with short payback and high annual ROI in power applications.
Optimizing Feedwater Heater Operation in a Nuclear Power Plant
Authors: Fitzgerald Bill
Published: October 2008

Feedwater heaters are a tough application even in a conventional power plant. Because of the complicated control scheme and the cascading effects between heaters, the levels in the heaters tend to cycle, reducing their ability to effectively transfer heat to the feedwater and wearing out many of the components that surround them. This situation is made even worse in a typical nuclear plant where the control schemes are normally built on obsolete local pneumatic control platforms that do not have the flexibility to be tuned for optimum performance. This paper will present the basics of a step by step analysis of a feedwater heater system in a Boiling Water Nuclear Reactor that is aimed at optimizing the individual field devices in the system and then coupling them up to a state of the art control system. It will illustrate the importance of field device selection and setup, and demonstrate several new tools available that will insure that the system is operating at peak efficiency. The summary will detail the resulting improvements in process control and their impact on reducing operations and maintenance costs, while driving up overall efficiency in the plant.
Simulation of Gas Turbine Reacting Flows
Authors: Amano R. S. , Xie J.
Published: October 2008

A study of spray combustion with porous inserts was performed using an on-axis fuel used in a concentric Jet-A. Combustion performance was evaluated by measuring exhaust emissions and flame temperatures for different operating conditions with and without ceramic foam inserts of various properties. The results indicated that the enhanced heat transfer in the flame zone could reduce nitrogen oxides and unburned hydrocarbon emissions. Placing a second porous layer downstream could yield further reductions in both emissions. The results for different firing rates and equivalence ratios revealed the residence time in the porous layer is an important factor regulating combustor performance.
Visualization of Flooding in Operating Fuel Cell
Authors: Zhang Feng-Yuan , Yang Xiao-Guang , Wang Chao-Yang
Published: October 2008

Flooding has been considered one of the important issues for the limitation of performance and durability of fuel cell. The flooding in fuel cell is investigated by developing visualization system with high spatial resolution, which is designed to give close images and movies of emergence, coalesce and removal of droplets in fuel cell. It has been shown that capillary force plays dominant role in liquid removal at low flow velocity, which is a typical operating condition in fuel cell. Increasing the hydrophilic properties of side walls and front wall of flow channel will result in higher liquid spreading and removal rates; while larger contact angle on GDL surface is preferred. The spreading time on front surface could be greatly reduced by decreasing the width of the flow channel. To get a stable performance of fuel cell, the water accumulation rate should be designed to be smaller that the ability of water removal.
A New Intelligent Measurement System of Torsional Vibration for Turbine-Generator Set
Authors: Du Dongmei , He Qing , Wang Zengqin
Published: October 2008

With wide application of large-scale turbine-generator sets, the torsional vibration of large-scale turbine-generator set has become the focus of study. Exact measurement of torsional vibration is the key. Proceeding from actual conditions of turbine-generator set, this paper has fully considered the precision of measuring and actual demand for application and developed a new intelligent measurement system of torsional vibration. This system configured two channels of measuring torsional vibration and eight A/D channels that can accept voltage or current ranged from 4 to 20mA. So the system can measure not only torsional vibration of shafts but also other state parameters, such as three-phase currents, voltages and load of set. The system consists of sub intelligent acquiring card, main PC computer and monitoring program. Data exchange between sub system and main computer is accomplished with the help of the FIFO memory. This structure enables signal acquirement and analysis to operate simultaneously and make full of the real-time monitor function of microprocessor and the rapid data processing ability of PC. Adopting 80C196KC chip with 20MHz frequency as the core and making use of HSI function, the system realizes on-line exact measurement of torsional vibration with the resolution of 0.014°. The whole signal processing is controlled by program, which improves the system’s flexibility, so that it can be used in many kinds of situations. According to the experiment result, it is proved that this system is easy in operation, steady in running and excellent in anti-interference ability.
Combined Measurement Uncertainty on Two Dependent Performance Tests
Authors: Soltani Mehdi , Dieck Ron , Ip Sang
Published: October 2008

Measurement uncertainty analysis plays an important role in the evaluation process of the net electrical output and the net heat rate during a power plant performance test. Aside from the technical aspect of the test, it bears very significant commercial consequences for the test parties. The ASME Performance Test Codes (PTC19.1) provides elaborative guidelines for test uncertainty analysis. In a combined cycle power plant test, the test uncertainty is heavily influenced by the measuring devices, corrections to reference conditions, and the method by which the test is conducted. A rigorous measurement uncertainty analysis is required to document and minimize the potential gap between the test results and the “actual true” net electrical output and net heat rate of the plant. The purpose of this paper is to estimate the measurement uncertainty of a combined cycle power plant consisting of two power trains. It includes the consideration of correlated uncertainties. Each power train is comprised of a gas turbine, a Heat Recovery Steam Generator (HRSG) and a steam turbine. For the multiple train power plants, some of the measured parameters are not independent and therefore the systematic errors are partially correlated. In this paper, the correlated systematic uncertainties and their contribution to the total uncertainty are evaluated. The uncertainty results are compared with the case when the systematic uncertainties resulting from correlated errors are ignored. Not properly considering the correlated terms may under estimate the uncertainties by over 30%.
Preventing Failures by Using No-Tube-in-the-Window (NTIW) Baffling in Feedwater Heater Design
Authors: Muldoon Thomas J.
Published: October 2008

High and intermediate pressure feedwater heaters increase the thermal efficiency of a power plant. During their lifetime they are subject to many different failure, mechanisms. Some of these failures are attributed to flow induced vibration resulting from operation at high overload conditions and load cycling. No-Tubes-in-the-Window (NTIW) baffle designs have been used for many years in the design of power plant and process plant heat exchangers. This baffle design is typically used in larger units which have high flows are susceptible to failures attributable to flow induced vibration. The NTIW design allows for the inclusion of intermediate supports between baffles that allows the design engineer to “tune” the tubes by increasing their natural frequency to levels above any possible flow condition. Utilizing a NTIW baffle design, several of these operational failure mechanisms can be directly addressed in the design and fabrication stage of a new or replacement feedwater heater. In particular, the NTIW can be designed to have extremely short unsupported spans and excellent vibration characteristics even at the highest predicted loads. The design also incorporates a larger minimum bend radii which minimizes high U-Bend stresses as a result of differential leg expansion. The NTIW design puts the exhaust steam into the steam dome without the wet/dry conditions in the condensing zone area just outside the desuperheating zone. The ability to place intermediate tube supports in the baffle space allows the design engineer to have the flexibility to keep zone pressure drops low, even in high load situations.
Repairing Feedwater Heater Tubes Using Explosively Welded and Brazed Sleeves
Authors: Muldoon Thomas J.
Published: October 2008

Failures in either the desuperheating zone or drainscooling zone may occur during the long term operation of high pressure feedwater heaters. When the number of failures gets high, the risk of the loss of generation or availability often requires replacement of a feedwater heater. Often, it is important to maintain a reasonably high level of heater availability while the replacement is planned and procured. It is prudent to minimize the potential for a catastrophic set of tube failures which could result in the potential for a turbine water induction incident or an extended repair outage. In such cases, a repair strategy that includes the use of tube sleeves, also referred to as liners, can provide a high level of leak tightness and can provide the operating margin and reliability to help get a heater through a critical operating period, such as a summer high load demand. Installing a sleeve, which is bonded to the tube on both ends, can provide this level of integrity.
Case History: Generator Rotor Shorted Turn Induced Vibration Excursion
Authors: Palmer Ken A.
Published: October 2008

The diagnosis of a generator rotor vibration in a 1,000 MW nuclear plant unit is presented. Several vibration excursions were recorded between July and August 2002. The excursions were somewhat repetitive in shape, but erratic and presented a clearly worsening trend, which threatened the continuous operation of the unit. In addition to high bearing vibration levels, the vibration force was transmitted to the Generator’s Current Transformers showing vibration levels in excess of 18 mils. The diagnosis of the rotor vibration excursions was simultaneously conducted by the Original Equipment Manufacturer (OEM) and a third party. An existing rubbing condition in the exciter and the generator hydrogen seals is presumed to have contributed to the elevated vibration levels reached during the excursion. A flat orbit in the generator side of the low pressure rotor LP-C was also recorded during the investigation. The existing rubbing condition caused discrepancy in the diagnostic between both parties. The OEM attributed the excursions to that rubbing condition while the third party attributed it to Generator Rotor Shorted Turns. Later inspection of the generator rotor revealed that the second diagnostic was correct. The characteristics of the vibration condition, the trouble shooting approach and the solution are described in this article.
Third Party Certification of CCPP Personnel Raises the Level of Training Provided
Authors: Tarvin Larry G.
Published: October 2008

Training of combustion turbine combined cycle and simple cycle power plant personnel has for the most part been shown to be lacking for the following: 1.) Personnel attending EPC/OEM training have not received sufficient preliminary training to be able to fully utilize the higher-level unit specifics. 2.) The training does not address the unit specific job tasks. 3.) Training objectives do not relate to the unit specific job tasks. 4.) The unit specific training (OJT) is left up to the “Start-up” engineers who are deeply involved commissioning of the plant equipment. Therefore training of the operator ends up mostly consisting of learning by osmosis. Independent Third Party Certification or licensing of combined cycle power plant personnel forces the training to be upgraded to include unit specific job tasks and OJT documentation.
Real-Time Vehicle System Controller Design for a Hybrid Fuel Cell Bus
Authors: He Bin , Yang Minggao , Li Jiangqiu , Lu Languang
Published: October 2008

The Hybrid Fuel Cell Bus investigated adopts a hierarchy control system structure, of which the four main components have independent sub-controllers, and besides, a super-level Vehicle System Controller (VSC) was added to coordinate the system operation. The vehicle has dual power sources, fuel cell engine and battery, which implies that for a certain power demand of the driver, power distribution between them should be determined. This brings the possibility of system optimization while requires well coordination of the distributed sub-controllers in a system-level coherent way, which to some extent increases the complexity of controller design. Based on the experimental modeling of the fuel cell bus, this paper presents a systematic design method of the VSC supervisory control strategy to address these issues. For the validation of the developed VSC, a hardware-in-loop (HIL) simulation platform was setup. From the virtual tests, controller functions validation and parameters precalibration were achieved. Finally, the VSC was tested on the test bench and successfully applied to the target Hybrid Fuel Cell Bus. Experimental testing results show the satisfactory performances of the developed VSC.
Dry and Hybrid Condenser Cooling Design to Maximize Operating Income
Authors: Boulay Richard B. , Cerha Miroslav J. , Massoudi Mo
Published: October 2008

Reduced availability of the large quantities of water required for traditional wet condenser cooling systems has created a growing market for dry and hybrid cooling for power plants. These technologies significantly reduce overall water consumption, but with large capital cost and heat rate penalties. An important consideration in sizing air-cooled and hybrid condensing systems is the emergence of a spot market for electrical energy. Energy prices can vary over an order of magnitude, and are typically highest during summer conditions. This paper evaluates whether it may be more economical to over-size the cooling system to achieve lower backpressures during the summer and thus generate additional revenue when energy prices peak. A universal methodology for evaluating the impact of cooling system design on operating economics was developed. It consists of a capital cost database for the condensing system, a Gate/Cycle model used to evaluate the effect of cooling parameter selection thermal performance, climatological data to provide representative dry bulb and wet bulb temperatures for typical annualized operating profiles at each plant location, and historical spot market energy pricing for each plant location. Several different design points for the cooling system are examined to determine the optimum selection that maximizes the difference between revenue and cooling system capital cost recovery. A nominal 500 MW coal-burning power plant is used as the study basis to demonstrate the results of this methodology for both northeastern and southwestern sites in the USA.
ALSTOM-CPS San Antonio Retrofit of JK Spruce Unit 1 HP-IP Turbine: An Example of an Advanced Steam Turbine Upgrade for Improved Performance by a Non-OEM Supplier
Authors: Hogg Simon , Stephen Donald
Published: October 2008

This paper describes in detail ALSTOM’s steam path upgrade of JK Spruce Unit 1 GE ‘G2’ HP-IP turbine cylinder. The retrofit features high performance impulse technology three dimensional blade designs for short height turbine stages. Performance improvement was achieved through improved aerodynamic design and increased stage count in the HP expansion (the number of stages in the IP remained unchanged in order to maintain the steam conditions in an extraction part-way down the steam path). The unit was also converted from partial arc to full arc steam admission during the retrofit which resulted in additional performance improvement at full load conditions. Performance guarantees for the retrofit were given in the form of absolute values for HP and IP cylinder adiabatic efficiency and a guarantee on absolute post-retrofit output power. The guarantee levels were based on in-house performance prediction method for turbine cylinders employing the Company’s low reaction technology blading. The code is based on the method first described by Craig and Cox [1], which has been continuously updated and developed to correctly account for advances in the company’s steam path technology over time. The guarantee for the HP cylinder efficiency (excluding the effect of inlet valve pressure drop) was 93.0%, the IP cylinder was guaranteed to achieve an efficiency of 92.8% excluding valves. The retrofit performance achieved was verified by enthalpy drop tests on the HP and IP expansions and the guaranteed performance levels were achieved in both cases. The centre-gland leakage was also measured as part of the performance guarantee testing. A novel method using the centre-gland blowdown pipe was employed, as an alternative to the temperature variation method. This alternative approach is described in the paper. The retrofit has now been in operation for a period of approximately two years and following the initial guarantee testing, additional performance tests have taken place at various points during this period. The data allows any degradation in the performance of the retrofit cylinder over time to be assessed. This is also discussed in the paper.
The Flow Characteristics of Flue Gas Between the Fins of a Single Spiral Finned Tube
Authors: Sun Fengzhong , Shi Yuetao , Han Zhihang , Liu Yang , Huang Xinyuan , Wang Naihua
Published: October 2008

The spiral finned tubes are used as the substitute of bare tubes in heat exchangers, which is an effective method to reduce abrasion and fouling in boilers. The cold state test with PDA system has been made to study the distribution of granule concentration between fins. This experimental research has laid the foundation of analysis for further study why the spiral finned tube can reduce abrasion and fouling.
Research and Implementation of Soot-Blowing Optimization on 600MW Coal-Fired Boiler
Authors: Zhu Yu-Dong , Yan Wei-Ping , Gao Zheng-Yang , Wang Xing-He , Qin Zhan-Feng
Published: October 2008

The forecasting model of fouling rate on convective heat transfer surface is deduced, the fouling monitoring and sootblowing optimization model are built, and the sootblowing optimization system is set up in this paper. The intelligent sootblowing advisory system is conducted in a 600MW utility boiler. This system could improve boiler efficiency, reduce steam consumption, extend tubes’ life. The operation of sootblowers is very complicated to utility boiler in security and economy. As it is an arduous process to build the sootblowing optimization model and sootblowing strategy, so there are still further more to be investigated in many aspects.
Research on Optimization Model for Power Coal Blending Based on Genetic Algorithm
Authors: Liao Yanfen , Wu Changhong , Ma Xiaoqian
Published: October 2008

The slagging process is a popular problem in coal-fired power plants because the coal properties deviate from designed condition, at the same time, power plants is enduring a great pressure with the increasing of coal prices. Power coal blending provides an effective way to solve these two problems. In some traditional methods, blended-coal properties were usually treated by the weighted average method which induced the optimization solutions deviating from the actual results. The reason is that different coal property indexes are based on different benchmarks; for example, the sulphur content in coal is based on applied basis, while the slagging properties of blended-coal are calculated on air-dried basis, which was influenced by the contents of moisture and ash in each coal. In order to study the effects, based on the genetic algorithm, a model considering these two factors was build up to optimum the coal-blending scheme. Compared with the traditional weighted average method, the new model got higher slagging property indexes, as means the former method may include some coal blending schemes into the optimizing process, in which the real slagging parameters go beyond constraint standards. Therefore, in the case of coal-blending optimization to prevent slagging in furnace, these two factors are especially important and should be considered carefully to ensure the precise of slagging parameters, so as to obtain the optimum results both in the prices of coals and in slagging property.
The Low Load Characteristic and Energy-Saving Optimizing Control of Large Capacity Power Plant
Authors: Zhang Chunfa , Li Liping , Wang Huijie , Zhao Ning , Zhang Xuelei
Published: October 2008

The variable load operation of the large capacity power plant and the variable working condition calculation of thermodynamic system are important subject for research in thermodynamic engineering field all the time. When the current operation point of the power plant is far away from the rated mode, it is very important to analyze the thermo-economy of thermodynamic system and offer appropriate operation guidance in engineering practices. Based on the steam turbine’s variable working condition theory, this paper reveals the inherent characteristic of power plant under off-design condition. From the viewpoint of systematic engineering, according with thermodynamic system topological structure and system thermodynamic properties, the state model of thermo-economy has been studied and set up. Combining the optimization theory and the analytic equation of the heat consumption rate, the optimum operational main steam pressure setpoint has been offered to advanced control strategy. Thus the further intellectual optimum control can be put into practice, and the unit can meet the demand for safe and economical operation within the wider range of load.
Fuzzy Neural Network Modeling for Fault Diagnosis in Turbine Startup of a Power Plant
Authors: Chen Weiliang , Xia Guodong , Sun Hongyu
Published: October 2008

A fault set and a symptom set were established in order to exactly judge and to quickly dispose in turbine startup of a power plant. There are ten typical faults in the fault set and sixteen fault symptoms in the symptom set. In consideration of the various kinds of change directions and ranges of the fault symptom parameters, the fuzzy disposal of nine degrees is put forward to build a set of typical fault-character-sample mode. A neural network model for fault diagnosis was obtained by fuzzy theory and radial basis function, and it was validated by using evaluator. It shows that the fuzzy fault disposal and the swiftness of training constringency are very satisfied in turbine startup of this power plant.
Study and Application on Real Time Optimum Operation for Plant Units
Authors: Liao Yanfen , Cai Jiejin , Ma Xiaoqian
Published: October 2008

The optimum unit commitment is to determine an optimal scheme which can minimize the system operating cost during a period while the load demand, operation constrains of the individual unit are simultaneously satisfied. Since it is characterized as a nonlinear, large scale, discrete, mixed-integer combinatorial optimization problem with constrains, it is always hard to find out the theoretical optimal solution. In this paper, a method combining the priority-order with dynamic comparison is brought out to obtain an engineering optimal solution, and is validated in a power plant composed of three 200MW and two 300MW units. Through simulating the on-line running datum from the DCS system in the power plant, the operating cost curves are obtained in different units, startup/shut-down mode and load demand. According to these curves, an optimum unit commitment model is established based on equal incremental rate principle principle. Make target function be minimum gross coal consumption, the results show that compared with the duty-chief-mode that allocates the load based on operators’ experience, the units’ mean gross coal consumption rate is reduced about 0.5g/(kW·h) when operating by this unit commitment model, and its economic profit is far more than the load economic allocation model that doesn’t considered the units’ start-up/shut-down.
A New Method’s Application Study on the Main Steam Temperature System
Authors: Gu Junjie , Zhang Luanying , Qin Zhiming
Published: October 2008

When the temperature of main steam is taken as the plant of control, it will be a typical control plant of large dead-time and parameter-varying process. In this paper a new single-neuron PSD self-adaptive algorithm that based on Smith predictor was proposed, i.e., a compound controller was combined with Smith predictor and single-neuron PSD self-adaptive controller. Compared with conventional PID controller, the variety of main steam temperature can be maintains in a very small range and manipulated variable changes smoothly under large-scale variety of load. The results of simulation show that the system has favorable dynamic properties and good adaptability. Therefore, the scheme has hopeful application prospect.
An Analysis on Disk Vibration in Steam Turbine
Authors: Sun Yigang , Yu Ensun
Published: October 2008

A modal analysis of disk in steam turbine is discussed in this paper. The analysis is performed with two methods: modal analysis of integrated blades-disk and of cyclic symmetric structure with ANSYS. The disk mode shape is summed up in five shapes: the disk vibrates at each nodal diameter with blades vibrating mainly in axial A0 shape, in tangent A0 shape, in twist shape, in tangent A1 shape and the disk vibrates in umbrella shape. Finally a safety assessment about disk vibration is given in the paper.
RES Introduced Through Flame Image Processing and Visualization of 3-D Temperature Distribution in a Coal-Fired Boiler Furnace
Authors: Luo Zixue , Zhou Huai-Chun , Wu Lubin , Liu Zhiwei
Published: October 2008

It is possible to have a quick, high-quality monitoring, diagnosis and control system for the safe combustion process of a utility boiler with high efficiency. Compared with the delay characteristic of the steam response to the fuel or air disturbance into the furnace, the Radiant Energy Signal (RES) can reflect more quickly the combustion condition. Using a novel flame image processing technique, the 3-D combustion temperature distribution can be visualized and RES can be detected in real-time. So, a kind of control strategy to optimize the boiler combustion process and to improve the unit load control quality is feasible on the basis of RES. RES measuring system is developed according to the measuring theory of furnace flame images. 3-D temperature distribution and RES can be obtained transiently. In-situ experiments have been done to study the change of RES as regulating capacity of burners among different layers, disturbing the fuel mass flow rate, adjusting secondary air register, changing over-fire air and tilt angle in a 1025t/h fossil-fired boiler. Furthermore, the boiler efficiency and NOx emission have also been analyzed. The result shows that the dynamic response characteristic of RES is ideal to improve the combustion control quality of the unit.
Correction and Its Application for Flue Gas Measured Temperature of Boiler
Authors: Shen Yueliang , He Tiansong
Published: October 2008

The thermocouples of K type with one layer casing for reducing heat transfer by radiation was used to measure the flue gas temperature of two boilers with 670t/h evaporation. In order to diminish the measurement error, this paper offers a theoretical calculation method to correct the measured temperature basing on the heat transfer theory, the extraction thermocouple with three layers ceramic casing was used to check the reliability of corrected temperature. The measured temperature by extraction thermocouple is access to the corrected temperature, which means that the correction method in this paper has feasibility. This paper obtained the flue gas temperature and its distribution of two boilers with 670t/h evaporation applying such correction method, and analyzed the reasons why the reheat steam temperature is lower than design temperature for one of boilers. Although the flue gas temperature correction method in this paper isn’t perfect, it is benefit for improving the accuracy of measured temperature, reducing the temperature errors, and it has directive and reference functions for test or research engineers.
Thermodynamic Cycle Theory of Multiple Energy Levels in Thermal Power Plant
Authors: Yan Shui-Bao , Wei Xin-Li
Published: October 2008

In order to improve economic performance and management level, a new perfect theory of thermodynamic system needs to be established. The new theory can be used to predict changes of performance indexes of thermodynamic cycle in thermal power plant when parameters and structures varies, and to calculate operation performance indexes, and to support economic operation and optimum decisions. A new principle, called the Principle of Doing-Work Capability, and several new concepts are introduced into the Thermodynamic Cycle Theory of Multiple Energy Levels. According to the principle, several universal relations between state variants of thermodynamic cycle and thermal economic indexes of thermodynamic cycle can be conducted. Based on main thermodynamic cycle, deviation values of thermal economic indexes can be calculated by the new theory, and data that is used in calculation is easily obtained from online supervision system. Deviation analysis criterion varies with operation conditions. The new theory can supersede several existed thermodynamic cycle theories, such as the Cycle Function Method, and the Equivalent Enthalpy Drop Method, and the Matrix Method and so on. The new theory is more universal and systemic, and suitable to be used in supervision and control system of thermal power plant.
Heat-Balance Model and Intelligence Optimization for the Wastes-Incineration and Power Generation System
Authors: Ma Xiaoqian , Liao Yanfen , Guan Lin , Zhao Zengli , Li Haibin , Chen Yong
Published: October 2008

Aiming to obtain an optimum balance between economical profit and environmental protection, a cost-profit model based on heat balance is built up for urban refuse incineration power system, in which the air preheat temperature and oil consumption are taken as parameters, while the maximization of the incomes of the station is taken as the objective. Considering the steady burning as constraint, the influence of the varieties of throwing oil, as well as the electric price adjusting on optimum operation parameters and profits are analyzed according to the running process of urban refuse burning power plant. Three different government’s subsidy and punishments mode are introduced into the model due to the emission of trace organic matter to analyze the influence on the power station’s best running parameters and on the behavior of the power plants. Results reveal that the government’s subsidy to garbage treatment can restrain the function ways of rubbish power station effectively.
The System of Two-Phased Pyrogenation and Gasification Waste Incinerator
Authors: Li Zheng-Mi , Chen Ze-Peng
Published: October 2008

A novel environment-friendly energy-saving waste disposing equipment — the Two-phased Pyrogenation and Gasification Waste Incinerator (TPGI) is introduced. Basing on the study on the cause of dioxins forming and the mechanism to inhibit such forming, the mechanism of pyrolyzing-gasifying and combustion air control, a two-phased pyrogenation and gasification waste incinerator is successfully developed. Principle of operation of TPGI is emphatically analyzed, process steps of TPGI and the result of industrial use is presented. Research result shows that the TPGI is complete in combustion, free of secondary pollution, high in energy utilization efficiency, environment-friendly, of obvious economic result and of wide application prospect.
Experimental Research on Direct Gasification and Melting Incineration of Municipal Solid Waste
Authors: Hu Jianhang , Wang Hua , He Fang
Published: October 2008

Direct Gasification & Melting technology is tacking with the development of environment-friendly technology and products harmonized with giving impact on the external environment. The technological process can be described as: Waste is fed from one side of the melting furnace. The auxiliary fuels maybe various fuels, such as coal, oil and combustible gas et al. The auxiliary fuel is for melting the waste. The limestone is the basically controller of slag. Air is sent through the third tuyers into the secondary combustion zone, through the second tuyers into the pryolysis and gasifying zone, through the main tuyers into the high temperature combustion and melting zone at the lower portion. In the secondary combustion zone, a high temperature reducing atmosphere is established which suppress the generation of dioxins and pyrolyzed tar. In the pryolysis and gasifying zone, the waste is brought in mild fluidizing state and gasified by the injected high-speed air through the secondary tuyers. Through the zone, the non-combustible components fall into the high temperature combustion and melting zone the bottom of the furnace. The fluidization prevents bridging or hanging obstruction due to mutual melting of plastics and other materials. In the high temperature combustion and melting zone, the combustion of auxiliary fuels and fixed carbon melt the ash. During the flow-down period, the melted ash becomes homogeneous slag. Also in this process, lead and zinc are vaporized and removed from the slag. Then, the slag is continuously extracted through the extracting equipment along with metals. The slag that is recovered from the water bath is treated by magnetic separation to remove metals, and becomes a resource material. The combustion and melting is controlled at temperatures of 1400°C or higher. The concentrations of dioxins were less than 0.1 ng-TEQ/Nm3 at the smokestack outlet and 0.0012ng-TEQ/g at the slag.
Volatiles and Elements Release Characters of Micronized Coal at High Temperature
Authors: Liu Zhong , Yan Wei-Ping , Zhao Li , Wang Xiao-Min
Published: October 2008

Volatiles and elements release characters are key factors that affect NO reduction efficiency and coal burnout at high temperature. The tested coal was directly taken from the bunkers in a power plant where combusts Shenhua bituminous and Zhunge’er lignite blends (mass ratio is 1:1), the coal blends were re-sieved mechanically and four sizes of them were taken as experimental coals. We designed and constructed char-preparation systems ourselves. The coal and char quality analysis were conducted by Vario el III coal element analyzer, and volatiles release characters under high temperature were analyzed. More volatiles can be released from finer coal under the same conditions. Ash was taken as tracer, volatiles yield in the case of high heating rate in entrained flow reactor is much more that gotten from conventional proximate analysis. Various elements yield increase with the decrease of coal size. Therefore, when finer micronized coal is used as reburning fuel, not only more hydrocarbon roots are produced, but also the combustion characters are improved so that the burnout is improved.
Recent Development of Steam Turbines With High Steam Temperatures
Authors: Nomoto Hideo , Kuroki Yoshikazu , Fukuda Masafumi , Fujitsuka Shinya
Published: October 2008

Higher thermal efficiency of the power plant has been always essential and indispensable in order to decrease the impact on the environments. In this regard, enhancement of the steam conditions is the most fundamental and effective measure to achieve the goal of higher thermal efficiency. Recent steam conditions in Japan range from 593 to 610 degree C owing to the technological development. There are many aspects and areas of technology for the realization of such steam conditions, for instance, material development, cooling design, steam path development, casing design, and so on. Not only the research and development but also the accumulation of operational results is of importance to achieve a breakthrough in turbine design. Since the reliability is another dominant factor for steam turbines, reflection of manufacturing experience and operational results should be taken into consideration. In this paper, recent development of steam turbines with high temperatures will be presented focusing on their design features, material selections, operational results, etc. Furthermore, this paper deals with continuous efforts targeting even higher steam conditions, which are promising for future development of steam turbine technology.
Recent Life Assessment Technology for Existing Steam Turbines
Authors: Saito K. , Sakuma A. , Fukuda M.
Published: October 2008

A large and growing portion of electricity is produced by aging thermal power plants. Although excellent, high quality materials such as CrMoV steel and 12% Cr steel, etc. are used for the steam turbines, various forms of metallurgical degradation, due to creep and fatigue, etc. affect the parts and components during long-term operation at high temperature. Extending the life of steam turbines and ensuring high reliability requires life assessment technology, scheduled repairing, conversion, modification and upgrading of components in order to provide a stable power supply. As the high temperature parts and components of aged steam turbines are mainly metallurgically damaged by creep, fatigue and the interaction of both, life assessment combined with analytical and nondestructive methods is essential for realizing strategic plant life extension. We have developed a life assessment technology that takes material degradation into consideration, and have applied the procedure to more than 650 units and 2500 components since 1983. A rotor bore replication device was developed in 1989 for the purpose of nondestructive observation of creep voids and supporting the validity of life prediction results. This paper describes the technical features and applied experience of recent life assessment technology for existing high temperature steam turbines.
Development of Welded Rotors for High-Temperature Steam Turbines
Authors: Magoshi Ryotaro , Tanaka Yoshinori , Nakano Takashi , Konishi Tetsu , Nishimoto Shin , Shige Takashi , Kadoya Yoshikuni
Published: October 2008

Steam turbine plants face strict market demand for high-temperature operation, streamlining, and shortened delivery times. The welded rotor enables streamlining through the use of material most appropriate for high to low-temperature parts. The use of materials will also enable a shift to larger capacity and shorter delivery times. The hetero-material welded rotor consisting of 2.25CrMoV, 9%Cr, and 3.5NiCrMoV steel was developed to meet these demands and verified at Takasago combined cycle plant. The plant has been conducting commercial and proving operations on the rotors. In this paper the authors introduce verification of work execution, strength, thermal stability, inspection for the welded rotor, and actual machine commercial operation.
Influence of Radiation Reabsorption on Laminar Burning Velocity of Methane Premixed Flame Composed With Steam and Carbon Dioxide
Authors: Ebara Takumi , Iki Norihiko , Takahashi Sanyo , Park Won-Hee
Published: October 2008

Replacing the Nitrogen with another kind of inert gas such as steam and Carbon dioxide is effective for both reducing NOx and enhancing system efficiency in gas turbine combustor. But the flame properties of such radiative mixture are complicated because of the third body effect and radiation reabsorption. So, we made detailed chemical kinetic calculations including the effect of radiation reabsorption to clarify the premixed laminar flame speed of such mixture as one of the most important properties for controlling the combustion. The concentrations of mixture are varied, and addition of other species such as Carbon monoxide and Hydrogen are also calculated to simulate the utilization of reforming gas and partially oxidized gas. And the pressure was varied up to 5.0 MPa to simulate the 1700 °C class combined gas turbine system. The results show remarkable incensement of laminar burning velocity by considering the radiation reabsorption. Laminar burning velocities were accelerated up to 150% in cases of Methane–Oxygen and steam or Carbon dioxide mixture. It was found that preheating of upstream-unburned mixture caused this acceleration. And the influence of radiation reabsorption was much larger in case of lower pressure.
Modeling of NOx and CO Reactions for Commercial Scale Pulverized Coal Firing Boilers
Authors: Okazaki Hirofumi , Taniguchi Masayuki , Yamamoto Kenji , Ochi Kenichi
Published: October 2008

The NOx-CO reaction model was developed for commercial scale pulverized coal firing boilers. The model was used to decide optimize combustion performance and it featured simplified sub models of NOx reduction, pyrolysis and CO oxidation. To improve combustion performance of commercial scale pulverized boilers, it is most important to predict the distribution of NOx and CO concentrations and search for the best conditions in a short time. The NOx reduction sub model was developed for both volatile and char combustion. The pyrolysis sub model was developed from a comparison of Distributed Activation Energy Model results and experimental data. The CO oxidation sub model was characterized by its consideration of the effect of hydroxide radicals. The simulation gave a lower CO oxidation rate for a long reaction time, the same as the actual result. The NOx-CO reaction model successfully analyzed NOx and CO concentration distributions of commercial scale boilers for power plants (260–1000MW).
Operation Results of IHI Flue Gas Desulfurization System for Unit 1(1,000MW) at Hitachinaka Power Station and Unit 1 at Mizue Power Station
Authors: Sasaki Yoshiki , Tsumita Yoshimitsu , Torii Masahiro , Mori Yuusuke
Published: October 2008

Unit 1 at Hitachinaka Power Station, which is the newest 1,000MW coal fired power station of Tokyo Electric Power Co., Inc., entered into the commercial operation in December 2003. IHI (Ishikawajima-Harima Heavy Industries Co., Ltd.) constructed the flue gas treatment system with the state-of-the-art technology and low emission values. To meet demands for both reducing construction cost and high performance, IHI applied a single rectangular Absorber based on the simultaneous desulfurization and oxidation method, Nonleakage type Gas-Gas Heater (GGH) and Electrostatic Precipitator (ESP) at low-low temperature position. Unit 1 at Mizue Power Station of GENEX Co., Ltd., which is one of the independent power produces, entered into the commercial operation in June 2003. In this plant, IHI applied a high performance spray tower Absorber and wet type Electrostatic Precipitator (ESP) to meet the high desulfurization efficiency for vacuum residue oil firing and extremely rigorous regulation owing to location near the metropolitan area.