bluuebunny/crossref_metadata_2025 huggingface dataset:
The Roles of Operations, Maintenance, and Management in a Preventable Power Plant Explosion
Authors: Palmer John A.
Published: October 2008

An explosion in the Midwestern United States destroyed the boiler of a 450 MW coal and gas fired power plant, resulting in physical damages and lost revenues exceeding $0.5 billion. Through the years that the conditions leading to the explosion developed, the disaster might have been averted by any number of reasonable interventions by plant maintenance personnel, plant operators, or plant management. Many lessons may be gleaned through a careful retrospective analysis of the circumstances and events that led to the catastrophic explosion. The intent of this paper is to present a case study emphasizing the importance of operations and maintenance, with the appropriate coordination and oversight by management. In this particular case, operations failed to enforce requisite lockout/tagout procedures and to observe and understand the alarms that annunciated when a wastewater accident inundated the fuel safety system. Maintenance failed to employ proper cleanup and troubleshooting techniques. Management failed to assign repair responsibilities to the most qualified maintenance personnel and to ensure proper communication between the personnel in the various plant departments. The catastrophic result of these failures was an inadvertent release of a substantial quantity of natural gas that ultimately exploded, completely destroying the boiler and other plant systems. This case study does not focus on the implementation of new operations or maintenance technologies, rather the emphasis is on reinforcing the implementation of existing codes, procedures and protocols and strengthening communications among plant personnel.
Confinement Effects on Flow Dynamics in Swirling Flames
Authors: Archer S. , Gupta A. K.
Published: October 2008

Three-dimensional (3-D) flowfield data has been obtained using Particle Image Velocimetry (PIV) for varying swirl distributions in the burner. The 3-D data also allows one determine the local swirl number of the resulting flow. Flow characteristics of the resulting flowfield, both without and with combustion, have been examined for the effect of co- and counter-swirl under lean direct injection conditions using unconfined and confined combustor geometry. Experimental results of the effect of swirl and combustion are presented to simulate the flow dynamics of Lean Direct Injection (LDI) configuration gas turbine combustion. The selected configuration is typical because it does not make use a premixing zone and relies totally on the swirl and the injector to accomplish rapid mixing. Specifically, the effect of radial distribution of combustion air and swirl in a burner are examined under non-burning and burning conditions using propane as the fuel. The present study explores single swirler interaction with the use of an experimental double concentric swirl burner that simulates one swirler of a practical gas turbine combustor. Results showed that both swirl and combustion has significant effect on the characteristics of the internal and external recirculation zones. The calculated local swirl number differs significantly form that estimated using geometrical relationship derived from the vane angle only. The effect of combustion for the confined and unconfined geometries was also been found to be different. In the confined geometry combustion decreases the size of the recirculation zone. This is in contrast to that found for the unconfined conditions. Combustion enhances the recirculation zone in the unconfined geometry. Combustion provides greater velocity magnitudes than their counter non-combustion conditions. The counter-swirl combination resulted in smaller and more well defined internal recirculation regions. The results provide the role of swirl and combustion on the mean and turbulence characteristics of flows over a range of swirl and shear conditions between the inner and outer flow of the burner. This data provides important insights on the flow dynamics in addition to providing data for model validation and model development.
Dual Open Cycle Peaking Gas Turbine Power Plant
Authors: Anderson Rodger O.
Published: October 2008

The generation of electrical power is a complex matter that is dependent in part both on the anticipated demand and the actual amount of power required on the grid. Therefore, the amount of power being generated varies widely depending on the time of day, day of the week, and atmospheric conditions such as cold spells and heat waves. While the amount of power varies, it is recognized that maximum efficiencies are achieved by operating power generation systems at or near steady state conditions. With this in mind, there has been an increased use of gas turbine systems that may be quickly added online to the grid to provide additional power because gas turbine systems are typically well suited for being brought online quickly to provide spinning reserve or electrical generation. However, gas turbines are recognized as not being as efficient as other plant systems such as large steam plants because the gas turbine is an open cycle system where approximately 60 to 70 percent of the energy is lost as exhaust waste heat energy. One recognized method of increasing gas turbine efficiencies is to add a steam bottoming cycle to the exhaust system. However, these closed cycle systems are costly and they compromise the gas turbine’s quick starting capability. This paper discusses an open bottoming cycle that is simple, cost effective and well suited for peaking power generation service. It not only substantially improves the gas turbine simple cycle plant heat rate, but also provides the opportunity to greatly reduce the NOX emissions levels with the application of a low temperature SCR.
The Changing Face of Power Plant Statistics: New Changes to IEEE 762 and GADS
Authors: Curley G. Michael
Published: October 2008

For the last three years, GADS Services of the North American Electric Reliability Council (NERC) has worked with other members of the Institute of Electronic and Electrical Engineers (IEEE) to review and improve the IEEE Standard 762, “Definitions for Reporting Electric Generating Unit Reliability, Availability and Productivity.” IEEE 762 is the basis of equations and definitions for the NERC Generating Availability Data System (GADS). With the help of North American, European and South African colleagues, the IEEE 762 has moved closer to that used in other parts of the world. This paper explains several major changes to IEEE 762 to bring about the compatibility. It also mentions some applications that are used by NERC GADS.
The Practical Application and Innovation of Cleaning Technology for Condensers
Authors: Howell Andy , Saxon George
Published: October 2008

Maintaining clean condenser tubes is of vital importance for reliable, efficient power generation. Two major problems result from substances on the interior of tube surfaces: (1) Loss of heat transfer, and (2) Under-deposit corrosion. Internal tube fouling is nearly always detrimental to heat transfer, thus reducing the efficiency of steam condensing, resulting in a lower vacuum (higher pressure) and less efficient steam turbine operation. Under-deposit corrosion of tube material can result in through-wall leaks, permitting ingress of cooling water into high purity steam condensate. Because poor vacuum conditions in the condenser can reduce electric generating capacity, and contaminants in steam condensate can cause significant damage to boiler tubing and steam turbine materials, measures to prevent fouling or remove foulants must be applied. Early identification of fouling characteristics and a fundamental knowledge of cleaning system capabilities are essential in determining the most effective cleaning technology. Unique circumstances may require innovative solutions. The common causes of condenser tube fouling and the practical application and innovation of cleaning technology are discussed. State-of-the-Art methods for off-line mechanical tube cleaning are presented, and their effects on tube condition examined.
Analysis on Technology of High-Frequency Vibratory Stress Relief
Authors: He Wen , Ren Yaoxing , Chen Caijin , Ma Fai
Published: October 2008

In the paper, a new kind of Vibratory Stress Relief (VSR), which is called high-frequency VSR, is put forward. Firstly, the traditional VSR or low-frequency VSR is introduced, including its method and mechanism. Then a new kind of VSR experimental equipment, which exciting frequency is more than 1kHz, is suggested. The experimental results show that it could decrease the residual stress efficiently. Metallographic is also analyzed, which gives a fancy phenomenon: the number of dislocations in material decreases after high-frequency VSR, which seems that the material recovers its original and non-stress state; on the contrary, the number of dislocations in material increases after traditional VSR. Finally, the underlying prospect of new concept “high-frequency VSR” is estimated. The advanced concept will take the significant effect on the wide application of VSR and energy conservation.
Gas Turbine Compressor Casing Repair
Authors: Anderson Rodger O.
Published: October 2008

Many older heavy duty gas turbine models have a very simple compressor casing design for attaching the stationary blades. It consists of grooves machined into a cast iron casing into which are slid blades with square bases. These bases have extending ears on two sides that engage undercut grooves in the main groove. This design works well, however, when the blade groove is very close to an extraction slot this results in a thin ligament in the casing which eventually cracks. This allows blades to liberate into the flow stream which results in major engine damage. One engine, the GE frame 5 with compressor cast iron casings has a tendency to crack in the blade attachment groove at the horizontal joint in row 10 where the air extraction is taken. The casing hook tends to bend due to the aerodynamic forces on the blades. An analysis shows how the blade forces are transferred to the weak casing ligament. This results in a crack at the thin ligament. The bent and cracked casing hooks are generally visible through a borescope inserted into the extraction cavity from the air pipe flanges. If this situation is not repaired, the cracks can lead to both casing material and blade liberation into the compressor flow stream. A quick and low cost repair has been developed to restore these engines to a reliable operating condition.
Energy Management Systems: How They Work and Why They Save Money
Authors: Mahling Dirk
Published: October 2008

Energy management in large buildings and facilities has become a major issue due to the fluctuations of energy supply and demand. Saving energy, in particular electricity, while maintaining an adequate level of comfort for building occupants is a major consideration for those with responsibility for commercial facilities — including financial, operational and engineering personnel. This session first reviews the types of systems that have developed in this space and how they compare, feature by feature. Then, to simplify this landscape from an energy users perspective, an “energy readieness” classification is presented that allows energy users to pick a path and a set of systems that is most approriate for their individual situation.
A General C-H-O-N-S Fuel Combustion Program for Temperature and Product Species
Authors: Olinger David S. , Lilley David G.
Published: October 2008

As an aid to the simulation of combustion in the power generation industry, a computer code has been developed using Excel/VBA to permit the rapid calculation of adiabatic flame temperatures and product species compositions for a large variety of easily specified fuel and air reactant conditions. Results are calculated immediately for the cases of “air” (with specified oxygen volume percentage) as the oxidant, with and without dissociation. Alternatively, the product temperature may be identified, and then the heat transfer in the combustor is calculated. In the general computer code developed, the very general fuel is specified by way of its C-H-O-N-S values. Additional water content may be specified. The “air” is specified by way of the volume percentage of oxygen and the other component (nitrogen and/or carbon dioxide). The temperatures of each reactant (fuel and “air”) are specified by the user. The computer code is very user friendly, with automatic nested loops for parameter variation and automatic generation of graphs, which are particularly useful in assessing the particular process under consideration.
Performance of a Natural Gas Engine Using Variable Air Composition
Authors: Biruduganti Munidhar S. , Gupta Sreenath B. , McConnell Steve , Sekar Raj
Published: October 2008

A comparative analysis of nitrogen and oxygen enriched combustion is presented in this paper. Nitrogen enrichment of intake air is proposed as an alternative to Exhaust Gas Recirculation (EGR). NOx reduction by EGR is not very promising due to engine reliability concerns and increased maintenance costs. Air separation membrane, on the other hand, is a potential strategy for NOx reduction due to uncompromised reliability of engine performance. Oxygen-rich and nitrogen-rich streams are produced by passing air through a nonporous polymeric membrane. Nitrogen Enriched Air (NEA) reduces NOx formation by lowering in-cylinder combustion temperatures but with a compromise in Fuel Conversion Efficiency (FCE). However, advanced ignition timing improves FCE considerably. Oxygen Enriched Air (OEA), on the other hand, improves FCE due to the availability of extra oxygen for better combustion which results in higher bulk gas temperatures and NOx emissions. This behavior could be controlled by retarding the ignition timing. Experimental results of nitrogen and oxygen enriched combustion of a Kohler M12 generator (converted to operate with natural gas) is presented in this paper. A 68% reduction in NOx and a 0.8% drop in FCE were observed at −30 ATDC ignition timing (IT) with 2.1% N2 enrichment (40 slpm). A 9% O2 enrichment (40 slpm) at −30 ATDC IT improved FCE by 1% but with higher NOx emissions. The increase in NOx emissions was minimal with a 2% improvement in FCE at −10 ATDC IT and 9% O2 enrichment (40 slpm). Some of the drawbacks encountered were engine misfire at higher concentrations of nitrogen enriched air and retarded ignition timing resulting in poor FCE. This paper discusses both the approaches and highlights the benefits of nitrogen enrichment using an air separation membrane over its counterpart for NOx reduction.
Coal Quality and Its Impact on Power Stations Emissions Control
Authors: Allen J. W. , Parker K. R. , Sanyal A.
Published: October 2008

Although coal fired power generation plant was originally designed to operate on a particular coal, increasingly stringent emissions regulations have led to modifications to both the coal type and firing mode. Low sulphur (S) coals minimize the requirement for sulphur dioxide (SO2) scrubbing plant combustion modifications are used as the primary measure to reduce the emission of nitrogen oxides (NOx) and these changes in the firing regime and/or the coal type can also impact on the in boiler ash deposition, particulate collection and the overall efficiency of the boiler operation. Emission regulations requiring maximum NOx levels of 0.15lbs./MM.Btu. are at, or just below, the limit of NOx reduction achievable by primary measures and at this limit significant increases in unburnt carbon (UBC) in ash levels can be expected, which affect boiler efficiency and also the operation of any SO2 and particulate collection plant. Coals are usually purchased, in addition to price, on quality based on the well established proximate and ultimate analyses, whereas parameters derived from these basic analyses may be more effective in defining the behaviour of a coal, substituted for the original design coal, in order to meet current emissions regulations whilst still maintaining an acceptable operating efficiency.
Rated Fan Performance: Determining If It Is Accurate and Acceptable — A Case for Laboratory Verification Testing
Authors: Kaufman Steven G. , Martin Vern
Published: October 2008

With few exceptions, fan vendors do not normally provide a written guarantee for the aerodynamic performance of a fan or even identify tolerances for the rated performance. When requested, the vendor often refers to acceptance criteria established in accordance with fan industry recognized standards and publications issued by the Air Movement and Control Association, Inc. (AMCA). AMCA acceptance criteria are very subjective, allow for very wide tolerances and can result in a very low probability that the purchaser’s performance requirements are met. There are three options available to the purchaser. • Assume the risk that the fan may not meet the performance requirement. • Purchase an oversized fan such that the performance can be met even if the fan performs at the low end of its performance tolerance. • Insure that the purchased equipment will perform as specified and mitigate the risks of deficiency by requiring the vendor comply with a performance guarantee. Test procedures suitable for conducting fan performance guarantee tests are available in many published AMCA, ANSI, ISO and ASME performance test standards. These performance test standards typically provide a procedure to estimate the accuracy of the measurement in the form of an uncertainty analysis. However, the accuracy of the measurement does not necessarily address whether the measurement meets the requirement within an acceptable tolerance. Except for AMCA, these test standards generally do not stipulate acceptable performance tolerances. A tolerance stipulates how much the measured value is allowed to fall short or exceed the required specified value and still be deemed to be acceptable. The system designer should specify suitable acceptance tolerances with consideration of the design margins that have been applied to the flow, pressure and power requirements of the system. This technical paper outlines a guideline of how to assess the accuracy and validity of a vendor’s quoted performance and the implications on system design margins. A case is made for laboratory verification testing in situations where a performance guarantee is required. • Allows proactive verification before final design, manufacture or shipment takes place. • Verification and corrective actions do not interfere with plant startup and production. • Allows for proactive modifications to be made at a fixed cost to the buyer.
Ash Measurement at NRG Huntley Using High Temperature Strain Gauges
Authors: Breeding Charlie , Schmitt Joe , Zhuang Huiying
Published: October 2008

The paper presents the results of a unique method of ash measurement at the NRG Huntley station. High Temperature strain gauges were installed in the boiler penthouse. The gauges were located on rods that support the superheater pendants. Output from the gages measure ash accumulation and soot blower effectiveness. Output from the system is utilized in the soot blower control system to optimize blower operation. The system will allow less steam to be used for soot blowing while keeping the superheater clean at all times. This is valuable to the plant as a switch to 100% PRB coal is made. The paper will present details of the installation.
Applying Weibull Methods in Gas Turbine Component Data Analysis
Authors: Salzman Ronald H.
Published: October 2008

The intent of this paper is to explain the basic theory and steps involved in performing a Weibull analysis of gas turbine component data. It is also to illustrate through practical examples, the application of the theory discussed and to demonstrate the versatility of performing Weibull analysis. Real-world applications will include using Weibull analysis to identify batch problems in fuel nozzle support housings and a method to determine if the thrust bearing wear rate is best fit with a three-parameter Weibull or a lognormal distribution. Also, a special technique will be described to determine if Weibull distributions for blade path and flashback thermocouple failures are significantly different failure modes.
Combined Cycle Performance Test Correction With Duct Firing
Authors: Ip Sang , Soltani Mehdi
Published: October 2008

In a gas turbine combined cycle, the performance guarantees are based on a specific set of base reference conditions. The actual plant performance is measured during a performance test, which usually occurs under conditions different from the base reference conditions. ASME Performance Test Code (PTC) 46, “Performance Test Code on Overall Plant Performance,” [1] addresses various cycle configurations and the fundamental equations used to correct results at the test condition back to base reference conditions. When the test requires duct firing of the heat recovery steam generator(s), then developing the correction curves poses unique challenges to the cycle engineer. This paper will review the issues and techniques used to develop the appropriate correction curves for the duct-fired combined cycle.
Experience With Advanced Monitoring Tools
Authors: McNamara Brad , Stephan Carl-Ernst , Hobelsberger Max
Published: October 2008

The current economic situation in the global energy market demands a cost reduction in maintenance concurrently with high availability and reliability of critical plant components. A combination of state-of-the-art on-line monitoring and diagnostic systems with the necessary off-line inspections allows more reliable operation with extended durations between maintenance intervals by applying modern data mining and expert systems. Prerequisites for such a condition based maintenance strategy are the incorporation of all available information of the generator (i.e., design knowledge, fleet experience, history of the machine) and all diagnosis and monitoring information. The experience with a modular monitoring system covering the main elements of a generator will be demonstrated.
Combined Cycle Equipment Standardization: How Much Is Too Much?
Authors: Fontes Roger , Casey Richard , Alder Robert , Prewitt Roger
Published: October 2008

Many electric utilities in the United States are involved with construction of both combined cycle and combustion turbine generation. These utilities and the industry, as a whole, have the opportunity to carefully examine methods of equipment optimization when developing these new power stations. The Florida Municipal Power Agency (FMPA) anticipates installing at least three large combined cycle units and several smaller aero-derivative combustion turbine units within the next 15 years. As a generation owner and operator, FMPA management is examining lessons learned by other utilities, original equipment manufacturers and consulting engineers to develop a cost-effective approach to equipment standardization. This evaluation focuses on design, equipment procurement, as well as long-term operation and maintenance requirements.
The Positive Effects of Utilizing Continuous Hydrogen Replenishment in Electric Power Generators
Authors: Speranza John , Dusold Lawrence
Published: October 2008

The purity of hydrogen used within electric power generators has a direct effect on cooling efficiency, windage friction losses, generating capacity and generator longevity. Hydrogen’s high thermal conductivity is the primary reason it is used as the cooling media in a generator instead of air. Hydrogen has a thermal conductivity of nearly seven times that of air, and its ability to transfer heat through forced convection is about 50% better than air. Maintaining hydrogen’s high thermal conductivity through purity monitoring and continuous improvement is important to the overall operation of hydrogen cooled electric generators. Continuous hydrogen replenishment has been proven to be an effective technique in maintaining purity within hydrogen cooled electric generators. A properly implemented continuous replenishment system will maintain a consistent high level of purity, low gas dew point, and constant pressure within the generator.
Energy Saving in Operating Steam Power Plants Based on ASME Performance Test Codes
Authors: Farhad Siamak , Younessi-Sinaki Maryam , Saffar-Avval M.
Published: October 2008

The purpose of this paper is to show how the ASME performance test codes can be used as a low cost and efficient tool for energy survey in order to reduce fuel and power consumptions in operating steam power plants. In this regard, A 1000 MW steam power plant was selected and many studies were performed to evaluate the possibility and effects of performing such tests on this power plant. The results show that many of the instruments of this plant are suitable for the desired purpose and the tests can be applied for achieving energy saving. Also, the results show that the natural gas and heavy oil fuel consumptions have increased around 10 and 8.3 percent, respectively, relative to the design conditions of this plant and at least half of these increases can be reduced by proper adjustments of control devices and simple repairs.
General Calculation Model on the Influence of Heater Terminal Temperature Difference on Turbine Power
Authors: Wang Songling , Zhang Xuelei , Chen Haiping , Zhou Lanxin
Published: October 2008

Assessing exactly the influence of heater terminal temperature difference on turbine power is significant meaning for the design, operation and repair of thermodynamic system. The method adopted is based on heat balance equation and turbine power equation of thermodynamic system. Take the partial derivative of outlet water enthalpy on both sides of the above equations, the law of the formulas can be found. So, for different heater type, the general calculation model on the influence of heater terminal temperature difference on turbine power is derived in the paper. One important conception, which is called as terminal temperature difference equivalent enthalpy drops, is defined in the paper. The model discussed in the paper is proved to be possessed of the character of accurate, simple and more universal. Especially, it is suitable for on-line monitoring system of unit heat economy.
Temperature-Field and Thermal Stress in Tube and Its Accessories of Power-Boiler
Authors: Chen Baojiang
Published: October 2008

Due to the structure’s specialties, the heat-absorption distribution on the panel-style heated surface of power boiler isn’t uniform. There is a temperature-grade in the structure. Ordinary, it’s difficult to evaluate the safety of the heated surface with a specific temperature grade. Furthermore, the differential equations of temperature field and stress field are very troublesome to solve on the complicated temperature and structure boundary conditions. The non-uniform temperature field existed in panel-style heated parts of Power Boiler gives rise to the second stress in the structure. What about the temperature field under which the structure is safe? In this paper, the temperature fields of fin-tube-wall and other heated parts are considered. By the thermal-elastic mechanics method associated with a reasonable assumption and the Author’s understanding to ASME’s definition about secondary stress, the limit of temperature-differential is gained. It’s useful in the design of power boiler.
Study on Characteristic Curves of Creep-Fatigue Interaction on 12Cr1MoV Steel
Authors: Chen Jie-Fu , Li Hou-Yi , Lin Hong-Shu , Liu Hong-Jie
Published: October 2008

This paper states the experiment results of investigation of fatigue damage, creep damage and their interaction on 12Cr1MoV steel and welding joint. An envelop of the interaction between fatigue damage and creep damage which could be used in practice was first given in China. This envelop is compared with that of 2.25Cr1Mo steel given in ASME BPVC.
High Temp. High Pressure CFB Boiler Superheater Layout and Optimum Design
Authors: Zhou Yigong
Published: October 2008

This paper analyses pros and cons for three high pressure high temperature CFB boiler superheater system layout plans, makes quantitative analysis, put forwards optimized plans for boiler superheater system layout, and summarizes design principle for platen-type superheater.
FRD-200 Sea Water Desalination Spent Fuel Reactor
Authors: Song Danrong , Ding Xiaoting
Published: October 2008

FRD-200 sea water desalination spent fuel reactor is a low temperature, normal pressure reactor which utilize nuclear power plant spent fuel. It can be used for sea water desalination and heat supply or refrigeration for metropolis. The FRD-200 is mainly used for sea water desalination.
Mechanism Study and Influence Factors Analysis of Desulphurization in Flue Gas Circulating Fluidized Bed
Authors: Zhao Yi , Ma Shuang-Chen , Sun Xiao-Jun
Published: October 2008

At present Flue Gas Desulphurization by Circulating Fluidized Bed (CFB FGD) has been widely used to partly take the place of the Spray Dry Absorbers (SDA) due to its simple system, excellent performance, occupying less area, and less cost, etc. It has been considered internationally as one of the most promising FGD technologies. The mechanism of FGD in CFB is introduced in the paper. Based on the mass transfer theory of two-phases, the fundaments of absorption and adsorption in CFB are analyzed. The influence of particle attrition on mass transfer coefficient of liquid phase is analyzed in terms of the special phenomenon in CFB. The result indicates that abrasion is beneficial to completely utilization of absorbents and further absorption, and it also has an inconspicuously enhanced effect on mass transfer. Fine particle agglomeration is analyzed in the paper and the study results show that the main course of FGD in CFB is absorbing process. Based on the gas absorption, the key parameters that influence desulphurization efficiency are analyzed finally. Mechanism study and influence factors analysis of FGD in CFB could be provided as the references for improving desulphurization.
Integrated Optimum Gray Neural Network Model of Monthly Power Load Forecasting Based on Optimum Credibility
Authors: Niu Dong-Xiao , Lu Jian-Chang , Li Yuan-Yuan
Published: October 2008

For the monthly load with double trends of increasing and fluctuating, the integrated optimum gray neural network model of monthly load forecasting is proposed in the paper for the first time. In the model, we regard vertical historical data as the primitive array to forecast increasing trend by the gray model, and regard horizontal historical data as the primitive array to forecast fluctuating trend by the . Based on that, the concept of the optimum credibility is introduced, and the integrated optimum model is built in the paper. In the model, the double trends of monthly load are considered at the same time and the two models’ modeling characters are given attention. So the integrated model is superior to the model of single trend forecasting. An application case of the power load forecasting is given. Through the analysis to the monthly supplying electric capacity in LiaoNing power system, the corresponding integrated optimum gray neural network model is built. It is compared with other algorithms. The calculation results prove that this method raises accuracy of the monthly load forecasting greatly. For the weekly and seasonal load with the same double trends, the method has same suitability to them.
The Application and Research of Fieldbus and Expert System in the Chemical Examination Station of the Power Plant
Authors: Wang Tianhong , Yuan Guili , Bai Yan , Wang Zijie
Published: October 2008

The occurrence of the Fieldbus brings a revolutionary in the control field again, and the depth and scope exceed anyone historically, and introduce new era in automation. The Fieldbus control system (FCS) will have great influence in process control in the future. Though FCS is started to adopt in domestic power system, but adopt the FCS thoroughly is still not many. Normally, based on the originally control system, increase parts of control conception of FCS, and the application of combining the advanced control strategy (artificial intelligent, nerve network, expert system and so on) is fewer. This thesis intends to attempt actively and explore profitably in the development and application of the Fieldbus technology in the control of product process in the power plant. On the base of the explanation of the system and exhaust about the Fieldbus technology and the concept and principle of Fieldbus control system, I combine the tendency of the development of the thermal automation technology in power plant, use the prevalence of the Fieldbus adequately, and bring up the designing thought and scheme about the application of Foundation Fieldbus and expert system in the system of the auxiliary control in the power plant, in order to make the production and running of the power plant more convenient, more safe, more economical and more dependable. On the base of which, combining the practical project, the technology is applied in product process control of chemical examination station of the chemical water workshop in one domestic large power plant, and the level of the automation and the management is enhanced greatly. This would make great significance in theory and practical about the promotion and application of the technology of the Fieldbus and advanced control strategy in the power system especially in the power plant.
Study on Applications of State Feedback Based on NN Observer in Super-Heated Steam Temperature Control
Authors: Zhang Luanying , Qin Zhiming , Gu Junjie
Published: October 2008

It is difficult for the conventional PID control to adjust with the change of dynamic characteristics of the plants. By combing the state feedback based on Elman neural network state observer and the conventional PID, a new control system was presented in this paper. The unmeasurable states of the system was reconstructed through NN observer, the adaptivabilty of system was improved by state feedback. A simulation for power plant super-heated steam temperature control system using presented method is carried out, and resulting in that the control system performance is better than the conventional cascade control system.
Study on Reliability Design Technology of Steam Turbine Blades
Authors: Shi Jin-Yuan , Yang Yu , Sun Qing , Deng Zhi-Cheng
Published: October 2008

A reliability design method of steam turbine blades is presented. The method considers static stresses, dynamic stresses, endurance strength, safety ratios, vibration frequencies and excition force frequencies of blades as random variables. The strength and vibration design reliability of turbine blades is determined with the help of probabilistic design method. Some reliability calculation formulas are given together with some practical examples. With the reliability design method for steam turbine blades as given in this paper, the design reliability of steam turbian blades can be determined in the design stage. The method may provide some scientific basis for reliability design of steam turbine blades.
Application Study of the Intelligent Integration Fuzzy Control in Steam Turbine Governing System
Authors: Yuan Guili , Wang Tianhong , Liu Jizhen , Wang Zijie
Published: October 2008

Steam turbine governing system is a nonlinear system, both the oil motor and the electric-liquid converter contain the nonlinear loop, however, the control strategy of the steam turbine governing system still stay at the control with PID, but the tuner with PID based on the accurate model belongs to the linear control intrinsically, and it doesn’t adapt to the nonlinear object. Fuzzy control doesn’t need the accurate mathematical model of the object, which fit to the nonlinear system and possess a better robust performance, and its control mechanism conform to the human’s intuitivism description and thinking logic about the function of the control system. Furthermore, the control query table is available by off-line calculation, and the real-time performance is improved. Intelligent integration fuzzy control is adopted here, the fuzzy control adopted the fuzzy control algorithm of full-field with self-tuning factor, where the control regulation is illustrated by analyzing, and the expression is brevity, the algorithm is simple, prone to master and realize with computer, and has self-optimization. The integration adopt the intelligent integration control to eliminate the steady-state error and improve the accuracy of control system. The advantage of the fuzzy control and integration control is developed adequately. The simulation result enunciate that the performance of steam turbine governing system with intelligent integration fuzzy control designed here is better than witch with conventional PID control, carrying advantages such as small super-adjusting, high-speed response, short transition process time and no steady-state error and so on.
Study on the Method of On-Line Measurement of Water Content in Turbine Oil Based on Resonant Cavity Perturbation
Authors: Tian Song-Feng , Han Zhong-He , Yang Kun
Published: October 2008

The accurate measurement of water content in the turbine oil has great significant for guiding steam turbine safety and economy running. A method of the on-line measurement of the water content in the turbine oil based on microwave resonant cavity perturbation is presented in this paper, The author deduced the formula of the volume proportion of water content in turbine oil, the resonant cavity and the measuring system of this method is simple. The precision of measurement can be improved by selecting work pattern with high quality factor, advancing the measurement precision of the relative frequency deflection and adopting the lower thermal expansion coefficient material and the especial resonant cavity configuration. Ten PPM water content in turbine oil can be distinguished by this method.
Calculation of Static Strength of Steam Turbine Impeller
Authors: Ding Chang-Fu , Tian Song-Feng , Sun Li , Qian Jiang-Bo
Published: October 2008

Stress analysis of impeller is an important link in the structure design of the steam turbine and has important meaning to maintenances, monitoring, safety and life-span manage and assess of rotor of steam turbine. According to fundamental equations of stress and deformation of stream turbine impeller, this method combines the boundary value computing method of system of second order ordinary differential equation with unbinding optimization method. A procedure is programmed and second order ordinary differential equation is calculated. The sample shows that the result gotten is nearly equal to the results of Secondary Calculation. Compared with Secondary Calculation, this method is simple and it has the project employing value.
Experimental Study on the Performance of Heat Transfer of a Novel Liquid-Gas Two-Phase Flow Scrubber for Flue Gas Desulfurization
Authors: Fang Li-Jun , Song Hong-Peng , Zhou Qu-Lan , Hui Shi-En , Xu Tong-Mo
Published: October 2008

Gas-liquid screen, a novel liquid-gas two-phase flow type, is applied in a scrubber for WFGD. According to the characters of the flow type, heat transfer experiments have been conducted to study the temperature distribution of flue gas in the tower and find the relation between heat transfer coefficient, flue gas and liquid velocity. The results show that whether in concurrent or countercurrent tower the heat transfer coefficient will increase with L/G decreasing at a fixed gas velocity. The optimum position of heat transfer is at the top of the Gas-liquid screen. So multilayer ‘Gas-liquid screen’ could to be arranged to optimize the effect of heat transfer and reduce the industry cost. The formulas of the relation between heat transfer coefficient, flue gas and liquid velocity are gained. These can provide strong foundation for the engineers and the further mass transfer experimental study.
Calculation of the Multiphase Equilibrium of the Reaction in Wet Flue Gas Desulfuration
Authors: Zhou Qulan , Hui Shi’en , Xu Tongmo , Zhao Caihong , Shi Zhenhai
Published: October 2008

A computational code, which can be used to calculate gas-liquid-solid 3-phase equilibrium line, has been developed based on the principle of free energy minimum. Then the equilibrium lines of dissolution of SO2 and CaCO3 in water are obtained using the code. The results satisfy the mass and charge conservation and match well with the data in the references. Finally, multiphase equilibrium lines of the reaction in WFGD are calculated in different conditions. The results show that temperature, concentration of SO2, CO2, have different effects on the solubility of SO2 under initial conditions given in the paper. Temperature and concentration of SO2 have great effects, and the concentration of CO2 has a small effect. The solubility of SO2 increases as the partial pressure of SO2 increases, temperature decreases or the concentration of CO2 decreases. These conclusions have a great guidance on designing the tower of wet flue gas desulphurization.
Spectral Analysis of Pulverized Coal Combustion Stability
Authors: Yu Yuefeng , Ma Jun , Fan Haojie
Published: October 2008

Flame detecting and diagnosis of combustion in modern coal-fired boilers are very important to the safe and economical operating of power generation unit. So the effective real-time detection of combustion flame stability and in-time judgment are necessary. One of the important characteristics of combustion flame is a combination of flame jet fluctuation and flickering of flame radiation, which is a time random variable and reflects the combustion conditions. In this paper, after the data are acquired through the tests in our university’s laboratory, the power spectrum analysis using algorithm of fast Fourier transformation (FFT) and a self-organized neural network are applied into a diagnostic system for combustion conditions. At first, a time series of radiation intensity values of the flame, which fluctuate at a mean intensity value with a certain frequency are obtained through the photoelectric sensor. And then the time signal is converted to the power spectrum signal through the processing of FFT. Under the stable and unstable combustion conditions, the spectral intensity of the low frequency component of the converted signal has distinct magnitude. According to this method, software for the power spectrum analysis and the self-organized neural networks has been developed.
Study on Techniques for Online Measurement to Air and Pulverized Coal Mixture Flow Parameters of Coal-Fired Boiler in Power Plant
Authors: Pan Wei-Guo , Wang Yu , Cao Jiangmin , Zhou Yunlong
Published: October 2008

Through analyzing the air and pulverized coal mixture flow characteristics of coal-fired boiler in power plant, it is put forward that measuring pulverized coal flow parameters is based on energy conservation theory and arrangement rule of measuring point location is for improving measurement precision. System for measuring temperature and velocity and concentration of air and pulverized coal mixture flow is developed, and some functions of on-line measuring air-pulverized coal mixture parameters are achieved. Adopting those efficient measuring methods are able to improve boiler operation’s safety and efficiency.
Development of Sound Source Inquiry Equipment: The Sound-Visualizing Camera
Authors: Wada Hiroyuki , Suzuki Akira , Sugimoto Yasuo , Sugiyama Takeshi , Owaki Masanao , Yamashita Yasuhiro
Published: October 2008

Recently, the noise problems of electric power facilities such as noises of transformers, fans, or corona noises of insulators are increasing. When the noises exceed the regulation level on the boundary of site or cause bad influence on in-house workers, effective measures should be taken against noises to solve them. When considering the measures against noises, the sound source and loudness of the noises should be specified. But the accurate evaluation of the target sound by using sound level meter is difficult, because the sound which reaches the noise meter is the sound which contains unrelated sound except for the target. So authors have developed the sound-visualizing camera that can investigate the direction of sound with each frequency every 1Hz. In this paper, authors explain the principle and experimental results of the sound-visualizing camera and its application to various fields.
MHI Approach to Upgrading Old Steam Turbines
Authors: Minami Yoshihiro , Osaki Nobuhiro , Akaishi Yuji , Newsom William
Published: October 2008

As a result of high operation hours, older power plants have been subject to function and performance deterioration. As a result, there is an increased need to upgrade steam turbine units to improve performance and increase output. By studying the two performance enhancement upgrade projects listed below, you will be introduced to the design, manufacture and on-site installation work for the modification of a turbine generator. Also discussed is Mitsubishi’s method of harmonizing the new equipment/components with the existing non-OEM steam turbine. Both projects began in late 2003 and were successfully completed in early 2004 by Mitsubishi Heavy Industries, Ltd. (MHI). All delivery, installation and commissioning requirements were met and guaranteed performance was achieved for both units. • HP Turbine Component Upgrade – Pennsylvania, USA; • Modification of Turbine Casing – Korea.
Upgrading and Life Extension Technologies for Geothermal Steam Turbines
Authors: Sakuma A. , Matsuura T. , Suzuki T. , Watanabe O. , Fukuda M.
Published: October 2008

In some aging geothermal steam turbines, the increased steam consumption is found out due to time deterioration of the turbine parts, mainly caused by erosion, corrosion damages or deposits of impurities on the steam paths. Furthermore the heavy damage due to stress corrosion cracking or corrosion fatigue damage, etc. are observed on rotors, blades and other parts and components. On the other hand in other units, the turbine output capacity decreases according to aging decrease of geothermal well pressure, that is, inlet steam pressure of turbine. Under these circumstances, upgrading and life extension are required for reliability and performance on geothermal steam turbines, particularly the existing ones. And as the effective utilization of geothermal energy is important from the viewpoint of decreasing carbon dioxide on environment problem, these technologies can, needless to say be applied to new geothermal projects as well as the existing ones. This paper describes development and application of advanced steam path design such as nozzle and blade for improving reliability and performance, and of advanced rotor design and material including overlay coating technology for improving reliability and extending life. And also it describes uprating of the existing units in opposition to aged decreasing in the inlet steam pressure.
Recent Upgrading and Life Extension Technologies for Existing Steam Turbines
Authors: Suzuki T. , Matsuura T. , Sakuma A. , Kodama H. , Takagi K. , Curtis A.
Published: October 2008

Electricity generation utilities are increasingly looking for cost-effective solutions to maximise the value of aging steam turbine generator plant assets. To this end, retrofits of steam turbines after many years of operation have been carried out for the purpose of life extension of units, performance improvements, capacity up-rating, availability improvement, and improved environmental compliance. Major steam turbine manufacturers have continued to push forward the development of advanced technologies to satisfy demand from utilities by provided retrofit design that optimise the above criteria. This paper describes the advanced technologies adopted in the recent retrofits, including advanced steam path design and new last stage blades of improved efficiency, improved reliability, and of simplified or no maintenance. Retrofit case-studies of capacity up-rating and life extension are introduced to illustrate how these technologies have been applied and what has been the gain.