Operational Improvements for Startup Time Reduction in Solar Steam Turbines

2015 ◽  
Vol 137 (4) ◽  
Author(s):  
Monika Topel ◽  
Magnus Genrup ◽  
Markus Jöcker ◽  
James Spelling ◽  
Björn Laumert
Keyword(s):  
Thermal Stresses ◽  
Steam Pressure ◽  
Back Pressure ◽  
Temperature Gradients ◽  
Steam Turbines ◽  
Transient Operation ◽  
Startup Time ◽  
Time Reduction ◽  
Solar Resource ◽  
Turbine Model

Solar steam turbines are subject to high thermal stresses as a result of temperature gradients during transient operation, which occurs more frequently due to the variability of the solar resource. In order to increase the flexibility of the turbines while preserving lifting requirements, several operational modifications for maintaining turbine temperatures during offline periods are proposed and investigated. The modifications were implemented in a dynamic thermal turbine model and the potential improvements were quantified. The modifications studied included: increasing the gland steam pressure injected to the end-seals, increasing the back pressure and increasing the barring speed. These last two take advantage of the ventilation and friction work. The effects of the modifications were studied both individually as well as in different combinations. The temperatures obtained when applying the combined modifications were compared to regular turbine cool-down (CD) temperatures and showed significant improvements on the startup times of the turbine.

Operational Improvements for Start-Up Time Reduction in Solar Steam Turbines

2014 ◽  
Author(s):  
Monika Topel ◽  
Magnus Genrup ◽  
Markus Jöcker ◽  
James Spelling ◽  
Björn Laumert
Keyword(s):  
Thermal Stresses ◽  
Steam Pressure ◽  
Back Pressure ◽  
Temperature Gradients ◽  
Steam Turbines ◽  
Transient Operation ◽  
Start Up ◽  
Time Reduction ◽  
Solar Resource ◽  
Turbine Model

Solar steam turbines are subject to high thermal stresses as a result of temperature gradients during transient operation, which occurs more frequently due to the variability of the solar resource. In order to increase the flexibility of the turbines while preserving lifing requirements, several operational modifications for maintaining turbine temperatures during offline periods are proposed and investigated. The modifications were implemented in a dynamic thermal turbine model and the potential improvements were quantified. The modifications studied included: increasing the gland steam pressure injected to the end-seals, increasing the back pressure and increasing the barring speed. These last two take advantage of the ventilation and friction work. The effects of the modifications were studied both individually as well as in different combinations. The temperatures obtained when applying the combined modifications were compared to regular turbine cool-down temperatures and showed significant improvements on the start-up times of the turbine.

Reducing Thermal Stress in Turbine Cylinders Subjected to Cyclic Service

1962 ◽  
Vol 84 (4) ◽  
pp. 389-402 ◽  
Author(s):  
Walter Sinton ◽  
R. E. Warner
Keyword(s):  
Thermal Stress ◽  
Thermal Stresses ◽  
Current Problem ◽  
Temperature Gradients ◽  
Inlet Temperature ◽  
Steam Turbines ◽  
Cyclic Service ◽  
And Control

The current problem of cracked cylinders encountered on steam turbines subjected to cyclic service points up the need for a better understanding of the thermal stresses which cause the difficulty, and for techniques to minimize and control these stresses. This paper establishes an improved approach to operation based on applying instrumentation to monitor and limit temperature gradients to recommended values. Benefits of heating manifolds are discussed. The advantage inherent in flexible inlet features has been incorporated into current cylinder designs for units operating in the range of 850 to 950 F inlet temperature.

An Improved Test Facility for Studying Deposit Fouling on Steam Turbine Blades

2016 ◽  
Author(s):  
Alan R. May Estebaranz ◽  
Richard J. Williams ◽  
Simon I. Hogg ◽  
Philip W. Dyer
Keyword(s):  
Turbine Blades ◽  
Steam Pressure ◽  
Reactor Vessel ◽  
Test Facility ◽  
Test Results ◽  
Steam Turbines ◽  
Steam Power ◽  
Scale Test ◽  
Steam Turbine Blades ◽  
Asme Paper

A laboratory scale test facility has been developed to investigate deposition in steam turbines under conditions that are representative of those in steam power generation cycles. The facility is an advanced two-reactor vessel test arrangement, which is a more flexible and more accurately controllable refinement to the single reactor vessel test arrangement described previously in ASME Paper No. GT2014-25517 [1]. The commissioning of the new test facility is described in this paper, together with the results from a series of tests over a range of steam conditions, which show the effect of steam conditions (particularly steam pressure) on the amount and type of deposits obtained. Comparisons are made between the test results and feedback/experience of copper fouling in real machines.

scholarly journals ANALISIS KINERJA TURBIN UAP UNIT 3 BERDASARKAN PERFORMANCE TEST DI UNIT PELAKSANA PT.PLN (PERSERO) PEMBANGKITAN ASAM-ASAM

JTAM ROTARY ◽  
2021 ◽  
Vol 3 (1) ◽  
pp. 95
Author(s):  
Kemas Ronand Mahaputra
Keyword(s):  
Performance Test ◽  
Heat Rate ◽  
Steam Pressure ◽  
Outlet Temperature ◽  
Steam Turbines ◽  
Turbine Efficiency ◽  
Rate Calculation ◽  
Temperature And Pressure ◽  
Main Steam ◽  
Unit Unit

This study purpose to determine the performance of steam turbines Unit 3 of PT.PLN (Persero) Pembangkitan Asam-asam by comparing the results of the data obtained by each performance test. This research was carried out by taking data performance tests in 2012, 2017, 2018 and 2019 and then processing the data and obtaining turbine heat rate values and average turbine efficiency then comparing the values obtained in each year. The data taken is obtained from the rendal operation of PT.PLN (Persero) Pembangkitan Asam-asam, data variables taken are load, main steam temperature inlet, main steam pressure inlet, HP heater feed outlet temperature, HP heater outlet pressure, main steam flow. Temperature and pressure obtained are then searched for enthalpy values. The data obtained to calculate the value of the turbine heat rate and turbine efficiency on average per time from each performance test then averages the value of the turbine heat rate and turbine efficiency each time the data collection performance test is then compared with the data each year.The calculation of the turbine heat rate uses the heat & mass balance method by measuring the value of the incoming and outgoing fluid differences and comparing the load obtained, the efficiency of the turbine is obtained by dividing the energy of 1 kW with a turbine heat rate then multiplying by 100%. The average turbine heat rate calculation result for each performance test which is on May 23, 2012 is 2,701, October 27, 2017 is 3,136, September 5, 2018 is 3,005, May 21, 2019 is 3,113. The average turbine efficiency value on May 23, 2012 is 37.02%, October 27 2017 is 31.39%, September 5 2018 is 33.28%, May 21, 2019 is 32.12%. The performance of PT PLN (Persero) Pembangkit Asam-asam Implementing Unit Unit 3 has decreased from 2012 to 2019 which is 4.9%

Bi-Layered Model of Interfacial Thermal Stresses with the Effect of Different Temperatures in the Layers

2011 ◽  
Vol 87 ◽  
pp. 63-70 ◽  
Author(s):  
Sujan Debnath ◽  
Muhammad Ekhlasur Rahman ◽  
Woldemichael Dereje Engida ◽  
M. V. V. Murthy ◽  
K.N. Seetharamu
Keyword(s):  
Thermal Stresses ◽  
Physical Design ◽  
Temperature Gradients ◽  
Interfacial Stress ◽  
Stress Model ◽  
Interfacial Stresses ◽  
Linear Temperature ◽  
Layered Model ◽  
Die Attach ◽  
Different Temperatures

An interfacial shearing and peeling stress model is proposed to account for different uniform temperatures and thickness wise linear temperature gradients in the layers. This upgraded model can be viewed as a more generic form to determine interfacial stresses under different temperature conditions in a bi-layered assembly. The selected shearing and peeling stress results are presented for the case of die and die attach as commonly seen in electronic packaging. The obtained results can be useful in interfacial stress evaluations and physical design of bi-material assemblies, which are used in microelectronics and photonic applications.

Prospects for constructing cogeneration stations equipped with back-pressure steam turbines

2014 ◽  
Vol 61 (12) ◽  
pp. 880-883
Author(s):  
A. A. Ivanovskii ◽  
A. Yu. Kultyshev ◽  
M. Yu. Stepanov
Keyword(s):  
Back Pressure ◽  
Steam Turbines ◽  
Pressure Steam

Thermal Fatigue Evaluation Method Based on Power Spectrum Density Functions Against Fluid Temperature Fluctuation

2005 ◽  
Author(s):  
Naoto Kasahara ◽  
Nobuyuki Kimura ◽  
Hideki Kamide
Keyword(s):  
Thermal Stress ◽  
Power Spectrum ◽  
High Frequency ◽  
Thermal Stresses ◽  
Evaluation Method ◽  
Power Spectrum Density ◽  
Temperature Gradients ◽  
Fluid Temperature ◽  
Spectrum Density ◽  
Fatigue Evaluation

Fluid temperature fluctuates at an incomplete mixing area of high and low temperature fluids in nuclear components. It induces random variations of local temperature gradients in structural walls, which lead to cyclic thermal stresses. When thermal stresses and cycle numbers are large, there are possibilities of fatigue crack initiations and propagations. It is recognized that there are attenuation factors depending on fluctuation frequency in the transfer process from fluid temperature to thermal stresses. If a frequency of fluctuation is very low, whole temperature of the wall can respond to fluid temperature, because thermal diffusivity homogenizes structural temperature. Therefore, low frequency fluctuations do not induce large thermal stress due to temperature gradients in structures. On the other hand, a wall surface cannot respond to very high frequency fluctuation, since a structure has a time constant of thermal response. High frequency fluctuations do not lead to large thermal stress. Paying attention to its attenuation mechanism, Japan Nuclear Cycle Development Institute (JNC) has proposed a fatigue evaluation method related to frequencies. The first step of this method is an evaluation of Power Spectrum Density (PSD) on fluid, from design specifications such as flow rates, diameters of pipes and materials. In the next step, the PSD of fluid is converted to PSD of thermal stress by the frequency transfer function. Finally, the PSD of thermal stress is transformed to time history of stress under an assumption of random phase. Fatigue damage factors can be evaluated from stress ranges and cycles obtained by the rain flow wave count method. Proposed method was applied to evaluate fatigue damage of piping junction model tests conducted at Oarai Engineering Center. Through comparison with direct evaluation from measurements and predictions by conventional methods, the accuracy of the proposed method was validated.

Coordinated Control of Gas and Steam Turbines for Efficient Fast Start-Up of Combined Cycle Power Plants

2016 ◽  
Vol 139 (2) ◽  
Author(s):  
Yasuhiro Yoshida ◽  
Kazunori Yamanaka ◽  
Atsushi Yamashita ◽  
Norihiro Iyanaga ◽  
Takuya Yoshida
Keyword(s):  
Thermal Stress ◽  
Steam Turbine ◽  
Gas Turbines ◽  
Power Plants ◽  
Thermal Stresses ◽  
Control Method ◽  
Coordinated Control ◽  
Combined Cycle ◽  
Steam Turbines ◽  
Start Up

In the fast start-up for combined cycle power plants (CCPP), the thermal stresses of the steam turbine rotor are generally controlled by the steam temperatures or flow rates by using gas turbines (GTs), steam turbines, and desuperheaters to avoid exceeding the thermal stress limits. However, this thermal stress sensitivity to steam temperatures and flow rates depends on the start-up sequence due to the relatively large time constants of the heat transfer response in the plant components. In this paper, a coordinated control method of gas turbines and steam turbine is proposed for thermal stress control, which takes into account the large time constants of the heat transfer response. The start-up processes are simulated in order to assess the effect of the coordinated control method. The simulation results of the plant start-ups after several different cool-down times show that the thermal stresses are stably controlled without exceeding the limits. In addition, the steam turbine start-up times are reduced by 22–28% compared with those of the cases where only steam turbine control is applied.

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