Off Design Performance Prediction of Steam Turbines

2007 ◽  
Author(s):  
R. Senthil Murugan ◽  
P. M. V. Subbarao
Keyword(s):  
Power Plants ◽  
Calculated Data ◽  
Operating Conditions ◽  
Steam Turbines ◽  
Design Data ◽  
Technical Data ◽  
Design Performance ◽  
Design Variables ◽  
Steam Parameters ◽  
Time Specific

Steam turbines in coal fired power plants are designed for some fixed operating conditions. When operated at those fixed conditions, the turbines are supposed to give maximum cycle efficiency. But off-design conditions occur several times due to condenser variation, environmental change, plant aging, etc. Performance at those off-design conditions affects economy of operation. Hence prediction of performance at off-design conditions is necessary. In this work a 210 MW steam turbine is designed using available design data. Calculated data matched available data quite satisfactorily. Design condition heat cycle data and other available technical data were used for design. Three off-design conditions, varying steam flow rate, varying condenser pressure, and varying inlet steam parameters were considered for study of off-design performance. These effects were suitably incorporated to recalculate performance of the same turbine at these conditions. Performance characteristics are obtained by varying one off-design condition at a time. Specific examples also are solved by simultaneously considering all three mentioned off-design variables using actual field data. Off-design performance predictions were found to be satisfactory.

Competitive Bidding by Surrogate Modeling of Steam Parameter Influence on the Attainable Start Numbers of Turbine Casings

2020 ◽  
Author(s):  
Marcel Seiler ◽  
Vitali Züch ◽  
Peter Dumstorff ◽  
Henning Almstedt
Keyword(s):  
Wall Temperature ◽  
Surrogate Model ◽  
Power Plants ◽  
Fe Model ◽  
Steam Turbines ◽  
Require Time ◽  
Steam Parameters ◽  
Fast Prediction ◽  
Main Steam ◽  
Flexible Operation

Abstract The continued expansion of fluctuating energy sources such as wind turbines and solar systems will increase the demand for more flexible operation modes of power plants. Especially steam turbines with all their components will have to sustain a higher amount of start-stop cycles in order to compensate for variations in wind and solar radiation. Besides the rotor, inner casings are an example for main steam turbine components which are strongly loaded by thermal cycles at each start and shut down procedure. A precise prediction of the attainable number of start-stop cycles enables a more flexible operation within the guaranteed lifetime. However, this would require time-consuming FE calculations for each power plant due to their specific steam parameters. In this paper, a physics based surrogate model is discussed for a fast prediction of permissible start-stop cycles at plant specific steam parameters. The correlation between the physical properties from the surrogate model (wall temperature difference and the resulting stresses) and the attainable number of start-stop cycles from the FE model is determined. A validation with a different inner casing design within a usual wall temperature range confirms the high accuracy level of the surrogate model compared to uncertainties like material scatter or casting tolerances. With the provided approach typically a higher number of starts can be efficiently calculated in the bidding phase compared to assuming only one conservative value for each turbine type or size. Furthermore, the steam parameters can be optimized for increasing the number of starts to the required value without additional and time-consuming FE calculations.

The Influence of Cooling Flows on the Operating Conditions of the Ultra-Supercritical Steam Turbine Components

2010 ◽  
Author(s):  
Wojciech Kosman
Keyword(s):  
Numerical Modeling ◽  
Steam Turbine ◽  
Power Plants ◽  
Measurement Data ◽  
Test Stand ◽  
Operating Conditions ◽  
Temperature Fields ◽  
Inlet Section ◽  
Steam Turbines ◽  
Cooling Flows

This paper presents the results of the analysis on the heat transfer in the inlet section of an ultra-supercritical steam turbine. Such power generating units become the foundation of new coal-fired power plants. The monitoring of their operation is in many aspects similar to the traditional, sub-critical steam turbines. However, higher live and reheat steam parameters result in several key differences, which must be taken into the consideration when assessing the thermal and strength states of the turbines main components for the diagnostic supervision. One of the main differences is the presence of the cooling and designs specific for ultra-supercritical steam turbines, which aim to protect their components against overheating. The research described in this paper investigates the inlet section of the turbines, which is the area exposed to the highest thermal loads. The scope of the research includes both, numerical modeling and laboratory testing. A test stand has been built for the analysis of the flows in the inlet section. Cooling flows are under special attention here as their temperature field is coupled to the temperature fields of the turbine components (the rotor and the inner casing) due to the relatively small amount of the coolant. The paper provides detailed description of the test stand and some early measurement results, which involve the operation with cooling. Also the numerical modeling results are shown and compared to the measurement data.

scholarly journals Forecasting of residual resource of structural elements of long-term operation in extreme conditions (according to the materials of scientific report at the meeting of the Presidium of NAS of Ukraine, December 23, 2020)

2021 ◽  
pp. 47-52
Author(s):  
I.Ya. Dolinska ◽  
Keyword(s):  
Power Plants ◽  
Operating Conditions ◽  
The Body ◽  
Energy Approach ◽  
Process Models ◽  
Structural Elements ◽  
Steam Turbines ◽  
Corrosive Media ◽  
Delayed Fracture ◽  
Term Operation

Applying the laws of thermodynamics, a general energy approach is formulated to study the delayed fracture of structural materials under the action of force load (static, cyclic, shunting mode of its change), high temperatures, hydrogen-corrosive media, neutron irradiation. Based on the energy approach process, models and forecasting methods of residual resource of structural elements in the mentioned operating conditions are developed. Based on the energy approach and the basic concepts of the acoustic-emission method, the calculation models in the parameters of the AE signals for the analytical description of the materials and structural elements delayed fracture under exploitation conditions are developed. Residual resource of the elements of power equipment (steam pipeline, elements of steam turbines), oil and gas pipelines, elements of nuclear power plants and the body of the oil hydrocracking reactor, is calculated.

Eliminating Steam Blow Piping Overcleaning During Power Plant Startup

2008 ◽  
Author(s):  
Julie M. Jarvis ◽  
Allen T. Vieiria ◽  
Paul J. Babel ◽  
Paul J. Kochis
Keyword(s):  
Flow Rate ◽  
Power Plants ◽  
Dynamic Pressure ◽  
Turbine Blades ◽  
Service Condition ◽  
Complete Removal ◽  
Operating Conditions ◽  
Steam Turbines ◽  
Force Ratio ◽  
Foreign Materials

This paper investigates and justifies the use of a minimum necessary cleaning force ratio or cleaning factor for steam blows. Steam line blowing is an operational cleaning method used to clean steam piping and reheaters prior to turbine powering for steam power plants. The steam blows remove weld bead deposits, slag, debris, surface scale, and other foreign materials which could be carried into the steam turbines and damage the turbine blades during normal plant operation. Piping is blown, bypassing the turbine, with sufficient boiler pressure to ensure the dynamic pressure throughout the piping is greater than would be experienced during all plant operating conditions. By providing flow rates corresponding to the maximum service condition for any given section of piping, there will be sufficient kinetic energy to ensure complete removal of any impurities from the pipe. Historically, the required steam blow pressures are calculated to achieve a cleaning force ratio of 1.2. Cleaning Force Ratio (CFR) or Cleaning Factor (CF) is an industry-accepted factor that quantifies the ratio of required dynamic pressure for cleaning to maximum dynamic pressure experienced during system operation. For CFRs, the turbine vendors tend to have guidelines or ranges rather than definitive acceptance criteria. It is usually left up to the commissioning engineer, the Project Startup Manager and Owner to determine what is necessary for final acceptance. It is desirable to reduce the required minimum blowout pressure and flow rate to facilitate plant startup. By reducing the required minimum blowout pressure and flow rate, permanent plant equipment and temporary steam blow piping wear can be reduced and over cleaning avoided. Further, time between steam blows can be reduced. This paper examines the CFR guidelines for various turbine vendors and justifies reducing the CFR from 1.2 to 1.0. Advantages of the use of a minimum necessary CFR include reduced required steam blow pressures which result in safer steam blows, and less expensive temporary steam blow piping. Use of a minimum necessary CFR will still maintain the effectiveness of the steam blow.

scholarly journals Features of steam turbines diagnostics

2020 ◽  
Vol 178 ◽  
pp. 01059
Author(s):  
Ilia Murmanskii ◽  
Konstantin Aronson ◽  
Boris Murmansky ◽  
Andrei Sosnovskii ◽  
Vladimir Novosyolov ◽  
...  
Keyword(s):  
Power Plants ◽  
Operating Conditions ◽  
Specific Power ◽  
System Control ◽  
Steam Turbines ◽  
Diagnostic Systems ◽  
Auxiliary Equipment ◽  
Single Interface ◽  
Diagnostic Signs ◽  
Study Designs

Enterprises of energy equipment and operational utilities set sights on diagnostic systems. This is necessary for state control and maintenance planning of steam turbines. It is useful for digitalization purposes too. So far, some mathematical systems are already used. Algorithms for flow part, heat expansion system, control system, vibration-based diagnostics and auxiliary equipment are already designed. We designed algorithms just in principle. Adapting them, for the PT-75/80-90 turbine we met with difficulties. Firstly, we should connect them to a single interface. Secondly, adaptation should include features of the equipment, its state (if not new), even operating conditions. Diagnostic signs for each turbine are the most important. We define them based on the operational data. When adapting the algorithms, we reconsider the signs list. We also estimate its coefficients of importance again. This requires experts to study designs, calculations, and modelling. We also analyzed a large amount of operation data at various power plants. To define the state we use tests. Adapting is based on the modes of a specific power station. Following this strategy, we adapt general algorithms for various turbines.

Could biomass-fueled boilers be operated at higher steam temperatures? Part 3: Initial analysis of costs and benefits

TAPPI Journal ◽  
2014 ◽  
Vol 13 (8) ◽  
pp. 65-78 ◽  
Author(s):  
W.B.A. (SANDY) SHARP ◽  
W.J. JIM FREDERICK ◽  
JAMES R. KEISER ◽  
DOUGLAS L. SINGBEIL
Keyword(s):  
Flue Gas ◽  
Power Plants ◽  
Superheated Steam ◽  
Black Liquor ◽  
Simulation Software ◽  
Operating Conditions ◽  
Costs And Benefits ◽  
Steam Generation ◽  
Fireside Corrosion ◽  
Corrosion Resistant

The efficiencies of biomass-fueled power plants are much lower than those of coal-fueled plants because they restrict their exit steam temperatures to inhibit fireside corrosion of superheater tubes. However, restricting the temperature of a given mass of steam produced by a biomass boiler decreases the amount of power that can be generated from this steam in the turbine generator. This paper examines the relationship between the temperature of superheated steam produced by a boiler and the quantity of power that it can generate. The thermodynamic basis for this relationship is presented, and the value of the additional power that could be generated by operating with higher superheated steam temperatures is estimated. Calculations are presented for five plants that produce both steam and power. Two are powered by black liquor recovery boilers and three by wood-fired boilers. Steam generation parameters for these plants were supplied by industrial partners. Calculations using thermodynamics-based plant simulation software show that the value of the increased power that could be generated in these units by increasing superheated steam temperatures 100°C above current operating conditions ranges between US$2,410,000 and US$11,180,000 per year. The costs and benefits of achieving higher superheated steam conditions in an individual boiler depend on local plant conditions and the price of power. However, the magnitude of the increased power that can be generated by increasing superheated steam temperatures is so great that it appears to justify the cost of corrosion-mitigation methods such as installing corrosion-resistant materials costing far more than current superheater alloys; redesigning biomassfueled boilers to remove the superheater from the flue gas path; or adding chemicals to remove corrosive constituents from the flue gas. The most economic pathways to higher steam temperatures will very likely involve combinations of these methods. Particularly attractive approaches include installing more corrosion-resistant alloys in the hottest superheater locations, and relocating the superheater from the flue gas path to an externally-fired location or to the loop seal of a circulating fluidized bed boiler.

Structure and properties of compact articles from high-alloyed iron powder with adding of boron nitride

2020 ◽  
pp. 39-48
Author(s):  
B. O. Bolshakov ◽  
◽  
R. F. Galiakbarov ◽  
A. M. Smyslov ◽  
◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Boron Nitride ◽  
Grain Boundary ◽  
Bending Strength ◽  
Physical And Mechanical Properties ◽  
Operating Conditions ◽  
Structure And Properties ◽  
Steam Turbines ◽  
Friction Forces ◽  
Wide Range

The results of the research of structure and properties of a composite compact from 13 Cr – 2 Мо and BN powders depending on the concentration of boron nitride are provided. It is shown that adding boron nitride in an amount of more than 2% by weight of the charge mixture leads to the formation of extended grain boundary porosity and finely dispersed BN layers in the structure, which provides a high level of wearing properties of the material. The effect of boron nitride concentration on physical and mechanical properties is determined. It was found that the introduction of a small amount of BN (up to 2 % by weight) into the compacts leads to an increase in plasticity, bending strength, and toughness by reducing the friction forces between the metal powder particles during pressing and a more complete grain boundary diffusion process during sintering. The formation of a regulated structure-phase composition of powder compacts of 13 Cr – 2 Mо – BN when the content of boron nitride changes in them allows us to provide the specified physical and mechanical properties in a wide range. The obtained results of studies of the physical and mechanical characteristics of the developed material allow us to reasonably choose the necessary composition of the powder compact for sealing structures of the flow part of steam turbines, depending on their operating conditions.

"Recent Patents on the Triboelectrostatic Separation of Fly Ash"

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

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

scholarly journals Selection of Heat Pump Capacity Used at Thermal Power Plants under Electricity Market Operating Conditions

Energies ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 226
Author(s):  
Milana Treshcheva ◽  
Irina Anikina ◽  
Vitaly Sergeev ◽  
Sergey Skulkin ◽  
Dmitry Treshchev
Keyword(s):  
Electric Power ◽  
Heat Pump ◽  
Heat Load ◽  
Power Plants ◽  
Thermal Power ◽  
Heat Pumps ◽  
Operating Conditions ◽  
Energy Resources ◽  
Thermal Power Plants ◽  
Maximum Heat

The percentage of heat pumps used in thermal power plants (TPPs) in the fuel and energy balance is extremely low in in most countries. One of the reasons for this is the lack of a systematic approach to selecting and justifying the circuit solutions and equipment capacity. This article aims to develop a new method of calculating the maximum capacity of heat pumps. The method proposed in the article has elements of marginal analysis. It takes into account the limitation of heat pump capacity by break-even operation at electric power market (compensation of fuel expenses, connected with electric power production). In this case, the heat pump’s maximum allowable capacity depends on the electric capacity of TPP, electricity consumption for own needs, specific consumption of conditional fuel for electricity production, a ratio of prices for energy resources, and a conversion factor of heat pump. For TPP based on combined cycle gas turbine (CCGT) CCGT-450 with prices at the Russian energy resources markets at the level of 2019, when operating with the maximum heat load, the allowable heat pump capacity will be about 50 MW, and when operating with the minimum heat load—about 200 MW.

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