Upgrade of Thermal Stress Supervision and Lifetime Assessment

2003 ◽  
Author(s):  
Gerhard J. Weiss ◽  
Jerry A. Kopczynski
Keyword(s):  
Steam Turbine ◽  
Power Plants ◽  
Metal Temperature ◽  
Steam Power ◽  
Steam Power Plants ◽  
Calculated Stress ◽  
Protection Systems ◽  
Startup Time ◽  
Run Up ◽  
Turbine Design

Steam power plants have an average service life of 40 years. There are many power plants still operating with the original supervision systems. These plants were equipped with control, protection, and supervision systems, which were available at the time. Over the last 20 years, steam turbine control/protection systems’ capabilities have been greatly improved. New hardware and improved software are available today to extend the life of existing turbines. For example, older turbines were originally equipped with casing metal temperature measurements or with so-called mechanical temperature probes for stress supervision. These measurements assist operators during manual run-up and loading of the turbine. Today’s upgraded supervision systems use the original sensors to measure the turbine metal temperature. Existing temperature signals are used as inputs to the electronic modules. These modules calculate the actual stresses in rotors and/or casings and acceptable margins. In cases where the calculated stress exceeds the pre-set limits, the run-up or loading gradient is automatically reduced, thus optimizing startup time of the steam turbine and resulting in optimal usage of the turbine’s life. Based on many years of experience in steam turbine design and service, standard proven algorithms are used to determine stress calculations. Automatic stress limiters can be installed. Acceptable stresses as well as actual stresses and margins can be displayed on the Operator Station (HMI) and recorded. Based on these records the lifetime assessment can be performed. The operator can select either slow, normal or fast startup, which will influence the lifetime consumption.

scholarly journals Reheat and Regenerative Gas Turbines for Feed Water Repowering of Steam Power Plant

1995 ◽  
Author(s):  
G. Negri di Montenegro ◽  
M. Gambini ◽  
A. Peretto
Keyword(s):  
Steam Turbine ◽  
Gas Turbine ◽  
Flow Rate ◽  
Gas Turbines ◽  
Power Plants ◽  
Feed Water ◽  
Brayton Cycle ◽  
Energy Integration ◽  
Steam Power ◽  
Steam Power Plants

This study is concerned with the repowering of existing steam power plants (SPP) by gas turbine (GT) units. The energy integration between SPP and GT is analyzed taking into particular account the employment of simple and complex cycle gas turbines. With regard to this, three different gas turbine has been considered: simple Brayton cycle, regenerative cycle and reheat cycle. Each of these cycles has been considered for feed water repowering of three different existing steam power plants. Moreover, the energy integration between the above plants has been analyzed taking into account three different assumptions for the SPP off-design conditions. In particular it has been established to keep the nominal value for steam turbine power output or for steam flow-rate at the steam turbine inlet or, finally, for steam flow-rate in the condenser. The numerical analysis has been carried out by the employment of numerical models regarding SPP and GT, developed by the authors. These models have been here properly connected to evaluate the performance of the repowered plants. The results of the investigation have revealed the interest of considering the use of complex cycle gas turbines, especially reheat cycles, for the feed water repowering of steam power plants. It should be taken into account that these energy advantages are determined by a repowering solution, i.e. feed water repowering which, although it is attractive for its simplicity, do not generally allows, with Brayton cycle, a better exploitation of the energy system integration in comparison with other repowering solutions. Besides these energy considerations, an analysis on the effects induced by repowering in the working parameters of existing components is also explained.

The Role of Rotor Welding Design in Meeting Future Market Requirements

2013 ◽  
Author(s):  
T.-U. Kern ◽  
H. Almstedt ◽  
Th. Thiemann ◽  
S. Brussk ◽  
K. Niepold
Keyword(s):  
Steam Turbine ◽  
Power Plants ◽  
Turbine Rotor ◽  
Future Market ◽  
Higher Plant ◽  
Steam Power ◽  
Material Development ◽  
Steam Power Plants ◽  
High Efficient ◽  
Technical Features

The demand for current and future steam turbine components is driven by higher efficiency but also by higher plant cycling needs and optimized cost balance. An increase in efficiency increases the demand for higher life steam temperatures of up to 620/630°C for today’s units and of even up to 720°C for future steam power plants. The gap between required material properties in the hot and cold running parts of a steam turbine rotor is widened by the increased live steam temperatures and the increased demand for flexibility and adaptability to current and expected future energy market conditions. Besides further material development, welding is one measure to realize such contradictory rotor characteristics. Whereas 720°C is more a future related task, solutions for 560°C / 620°C apply already welded rotors. The paper discusses from a perspective of a steam turbine manufacturer the technical features to enable flexible high efficient rotor components with a focus on advanced welding technologies suitable for different large steam turbine components and what further steps for new welding technologies are under way.

Proven Practices in Chemical Control for Steam Power Plants

1967 ◽  
Vol 89 (3) ◽  
pp. 305-309
Author(s):  
F. G. Straub
Keyword(s):  
Water Treatment ◽  
Steam Turbine ◽  
Power Plants ◽  
Water Soluble ◽  
Steam Power ◽  
Boiler Water ◽  
Internal Corrosion ◽  
Steam Power Plants ◽  
The University ◽  
Water Treatments

The author has conducted research on boiler water treatment at the University of Illinois and in many steam power plants during the last forty-three years. This research covered the cause and prevention of water soluble and silica deposits in steam turbine, metal losses in the wet steam areas of the steam turbine, metal pickup in the preboiler feedwater cycle, internal corrosion in boiler tubes including oxygen embrittlement. The author reports that with proper control of the water treatment these difficulties can be prevented. He outlines the water treatments used and reports the favorable results obtained in boilers, many of which have operated for over twenty years (600–2600 psi). He also reports on the operation of a large number of boilers which have operated for a similar number of years without requiring internal acid cleaning. These results only cover the operation of conventional boilers with natural and controlled circulation.

scholarly journals Analisa Kerusakan Pipa Boiler Super Kritikal

2020 ◽  
Vol 4 (1) ◽  
pp. 24
Author(s):  
Mochamad Nanchy Chudhoifah ◽  
Dwita Suastiyanti ◽  
Pathya Rupajati
Keyword(s):  
Power Plants ◽  
Magnetic Layer ◽  
Metal Temperature ◽  
Short Term ◽  
Steam Power ◽  
Material Type ◽  
Steam Power Plants ◽  
Start Up

AbstrakBoiler adalah alat yang digunakan untuk mengubah air menjadi uap dengan cara dipanaskan menggunakan batubara sebagai bahan bakar utama. Pada pembangkit listrik tenaga uap dengan menggunakan boiler super critical berkapasitas 660 MW, temperatur uap 566 °C dan tekanan 240 bar memiliki pipa di area final superheater dengan jenis material SA213 – T91. Pada saat unit start up, pipa di area final superheater mengalami kebocoran sehingga pipa menjadi pecah. Pecahnya pipa menyerupai mulut ikan, hasil analisa penyebabnya kemungkinan karena Short Term Temperature. Melalui uji metalografi ditemukan adanya rongga-rongga dan retak pada struktur mikro, kemungkinan karena pengelupasan lapisan magnetik didalam pipa. Untuk itu pengoperasian boiler harus memperhatikan kenaikan metal temperatur tidak boleh melebihi 2°C/menit agar tidak terjadi pengelupasan lapisan magnetik pada pipa Boiler.Kata kunci: SA213-T91, retak, superheater.Abstract Boilers are tools used to convert water into steam by heating using coal as the main fuel. In steam power plants using super critical boilers with a capacity of 660 MW, steam temperatures of 566 ° C and pressure of 240 bar have pipes in superheater final area with material type SA213 - T91. When start of the unit, the pipe in the final superheater area has leaked so that the pipe was rupture. The rupture of a pipe like a fish's mouth, the results of the analysis cause may be due to Short Term Temperature. Through metallographic tests it was found that there were cavities and creeps on the microstructure, possibly due to the peeling of the magnetic layer in the pipe. For this reason, the operation of the boiler must pay attention to the increase in metal temperature should not exceed 2 ° C / minute so there is no exfoliation of the magnetic layer in the Boiler pipe.Keywords: SA213-T91, creep, superheater.

Evaluation of Si Coating on Ferritic Steels by CVD-FBR Technology in Steam Oxidation

2009 ◽  
Vol 289-292 ◽  
pp. 413-420 ◽  
Author(s):  
F.J. Bolívar ◽  
L. Sánchez ◽  
M.P. Hierro ◽  
F.J. Pérez
Keyword(s):  
Power Plants ◽  
Protective Coatings ◽  
Steam Oxidation ◽  
Steam Turbines ◽  
X Ray Diffraction ◽  
Steam Power ◽  
Factors Affecting ◽  
Steam Power Plants ◽  
Temperature And Pressure ◽  
Major Factors

The development of new power generation plants firing fossil fuel is aiming at achieving higher thermal efficiencies of the energy conversion process. The major factors affecting the efficiency of the conventional steam power plants are the temperature and, to a lesser extent, the pressure of the steam entering the turbine. The increased operating temperature and pressure require new materials that have major oxidation resistance. Due to this problem, in the last years numerous studies have been conducted in order to develop new coatings to enhance the resistance of steels with chromium contents between 9 and 12% wt against steam oxidation in order to allow operation of steam turbines at 650 0C. In this study, Si protective coatings were deposited by CVD-FBR on ferritic steel P-91. These type of coatings have shown to be protective at 650 0C under steam for at least 3000 hours of laboratory steam exposure under atmospheric pressure. Morphology and composition of coatings were characterized by different techniques, such as scanning electron microscopy (SEM), electron probe microanalysis, and X-ray diffraction (XRD). The results show a substantial increase of steam oxidation protection afforded by Si coating by CVD-FBR process.

Numerical and Experimental Investigations of the Transient Thermal Behavior of a Steam By-Pass Valve at Steam Temperatures Beyond 700 °C

2015 ◽  
Vol 7 (1) ◽  
Author(s):  
Anis Haj Ayed ◽  
Martin Kemper ◽  
Karsten Kusterer ◽  
Hailu Tadesse ◽  
Manfred Wirsum ◽  
...  
Keyword(s):  
Thermal Behavior ◽  
Power Plants ◽  
Numerical Approach ◽  
Life Assessment ◽  
Experimental Investigations ◽  
Steam Power ◽  
Steam Power Plants ◽  
Cyclic Operation ◽  
Measurement Results ◽  
Transient Thermal

Increasing the efficiency of steam power plants is important to reduce their CO2 emissions and can be achieved by increasing steam temperatures beyond 700 °C. Within the present study, the thermal behavior of a steam by-pass valve subject to cyclic operation with 700 °C steam is investigated experimentally and numerically. An innovative numerical approach was applied to predict the valve’s thermal behavior during cyclic operation, which is essential for fatigue life assessment of such a component. Validation of the applied numerical approach has shown good agreement with measurement results, indicating the potential of its application for the valve design process.

Energy Storage Using Low-Pressure Feedwater

1985 ◽  
Vol 107 (3) ◽  
pp. 569-573 ◽  
Author(s):  
C. M. Harman ◽  
S. Loesch
Keyword(s):  
Energy Storage ◽  
Power Plants ◽  
Storage System ◽  
Energy Storage System ◽  
Low Pressure ◽  
Steam Power ◽  
Low Pressure Turbine ◽  
Availability Analysis ◽  
Steam Power Plants ◽  
And Storage

A method for increasing the peak output of steam power plants through use of a low-pressure feedwater storage system is presented. The generalized availability analysis involves only the low-pressure turbine, low-pressure feedwater heaters, and the storage system. With daily cycling and storage charging at near base load conditions, the turnaround efficiency of the energy storage system was found to approach 100 percent. Storage system turnaround efficiency is decreased when the energy is stored during plant part-load operation.

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