TY  - JOUR
AU  - Stevanović, Vladimir
AU  - Ilić, Milica
AU  - Djurović, Željko
AU  - Wala, Tadeusz
AU  - Muszynski, Slawomir
AU  - Gajić, Ivan
PY  - 2018
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/2939
AB  - Coal-fired thermal power plants (TPPs) had been generally designed to cover base loads of electricity consumption. Nowadays, they should be flexible to participate in the primary frequency control of electric system, especially because of increased number of wind and solar plants with intermittent electricity production. In this paper a new method for the primary power control in TPPs is presented, based on the feedwater flow rate changes between the feedwater heaters (FWHs) and an additional high pressure economizer. The achieved primary power control reserve is demonstrated by measurements at the lignite-fired 650 MWe TPP after its retrofit by the installation of the high pressure economizer in parallel with FWHs. In addition, the TPP transient operation during the primary control are simulated and analyzed with the developed thermal-hydraulic model of the steam turbine heat regeneration system. The control reserve of approximately 10 MWe is shown both by measured data and results of numerical simulations. The control reserve is originally provided by the fresh steam throttling in front of the turbine, but this throttling can be reduced by the application of the new method. The rates of change of wall temperatures of FWHs tubes are within allowed limits during the transients.
PB  - Pergamon-Elsevier Science Ltd, Oxford
T2  - Energy
T1  - Primary control reserve of electric power by feedwater flow rate change through an additional economizer - A case study of the thermal power plant "Nikola Tesla B"
EP  - 798
SP  - 782
VL  - 147
DO  - 10.1016/j.energy.2018.01.102
ER  - 

@article{
author = "Stevanović, Vladimir and Ilić, Milica and Djurović, Željko and Wala, Tadeusz and Muszynski, Slawomir and Gajić, Ivan",
year = "2018",
abstract = "Coal-fired thermal power plants (TPPs) had been generally designed to cover base loads of electricity consumption. Nowadays, they should be flexible to participate in the primary frequency control of electric system, especially because of increased number of wind and solar plants with intermittent electricity production. In this paper a new method for the primary power control in TPPs is presented, based on the feedwater flow rate changes between the feedwater heaters (FWHs) and an additional high pressure economizer. The achieved primary power control reserve is demonstrated by measurements at the lignite-fired 650 MWe TPP after its retrofit by the installation of the high pressure economizer in parallel with FWHs. In addition, the TPP transient operation during the primary control are simulated and analyzed with the developed thermal-hydraulic model of the steam turbine heat regeneration system. The control reserve of approximately 10 MWe is shown both by measured data and results of numerical simulations. The control reserve is originally provided by the fresh steam throttling in front of the turbine, but this throttling can be reduced by the application of the new method. The rates of change of wall temperatures of FWHs tubes are within allowed limits during the transients.",
publisher = "Pergamon-Elsevier Science Ltd, Oxford",
journal = "Energy",
title = "Primary control reserve of electric power by feedwater flow rate change through an additional economizer - A case study of the thermal power plant "Nikola Tesla B"",
pages = "798-782",
volume = "147",
doi = "10.1016/j.energy.2018.01.102"
}

Stevanović, V., Ilić, M., Djurović, Ž., Wala, T., Muszynski, S.,& Gajić, I.. (2018). Primary control reserve of electric power by feedwater flow rate change through an additional economizer - A case study of the thermal power plant "Nikola Tesla B". in Energy
Pergamon-Elsevier Science Ltd, Oxford., 147, 782-798.
https://doi.org/10.1016/j.energy.2018.01.102

Stevanović V, Ilić M, Djurović Ž, Wala T, Muszynski S, Gajić I. Primary control reserve of electric power by feedwater flow rate change through an additional economizer - A case study of the thermal power plant "Nikola Tesla B". in Energy. 2018;147:782-798.
doi:10.1016/j.energy.2018.01.102 .

Stevanović, Vladimir, Ilić, Milica, Djurović, Željko, Wala, Tadeusz, Muszynski, Slawomir, Gajić, Ivan, "Primary control reserve of electric power by feedwater flow rate change through an additional economizer - A case study of the thermal power plant "Nikola Tesla B"" in Energy, 147 (2018):782-798,
https://doi.org/10.1016/j.energy.2018.01.102 . .

TY  - CONF
AU  - Stevanović, Vladimir
AU  - Petrović, Milan M.
AU  - Wala, Tadeusz
AU  - Gajić, Ivan
AU  - Muszynski, Sławomir
PY  - 2018
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/4526
AB  - A substantial potential exists for the thermal power plants efficiency and power upgrades by the 
utilization of flue gas waste heat at the steam boiler. The paper presents solutions for the waste heat 
utilization and different balance of plant modifications for the regeneration of waste heat into the plant 
thermodynamic cycle. A comparative analysis of different solution modes is performed for the more 
than 30 years aged lignite-fired 2x620 MWe power plant “Nikola Tesla B”. Different modes of waste 
heat regeneration into the plant cycle are flue gas cooling by the “cold” feedwater taken from the main 
feedwater pump discharge line before high pressure heaters, by the “hot” feedwater after the high 
pressure heaters and by the condensate taken from the low pressure condensate line. The energy 
efficiency and power upgrades of proposed methods is evaluated and compared. The highest increase 
of power plant efficiency is achieved by the flue gas cooling by the feedwater taken from the feedwater 
pump discharge line. This solution was implemented within the first phase of power plant overhaul, with 
a reduction of the flue gas temperature for more than 20 
oC and the boiler and power plant efficiency 
increases of approximately 2 and 0.53 percentage points respectively.
PB  - Institute of Thermal Technology, Gliwice, Poland, Silesian University of Technology
C3  - Proceedings of the 5th International Conference on Contemporary Problems of Thermal Engineering Energy Systems in the Near Future: Energy, Exergy, Ecology and Economics, (CPOTE 2018), Gliwice, Poland, 19-21 September, 2018
T1  - Analysis of efficiency and power upgrades at the lignite-fired 2x620 MWe power plant by steam boiler waste heat utilization and different balance of plant modifications
EP  - 392
SP  - 385
UR  - https://hdl.handle.net/21.15107/rcub_machinery_4526
ER  - 

@conference{
author = "Stevanović, Vladimir and Petrović, Milan M. and Wala, Tadeusz and Gajić, Ivan and Muszynski, Sławomir",
year = "2018",
abstract = "A substantial potential exists for the thermal power plants efficiency and power upgrades by the 
utilization of flue gas waste heat at the steam boiler. The paper presents solutions for the waste heat 
utilization and different balance of plant modifications for the regeneration of waste heat into the plant 
thermodynamic cycle. A comparative analysis of different solution modes is performed for the more 
than 30 years aged lignite-fired 2x620 MWe power plant “Nikola Tesla B”. Different modes of waste 
heat regeneration into the plant cycle are flue gas cooling by the “cold” feedwater taken from the main 
feedwater pump discharge line before high pressure heaters, by the “hot” feedwater after the high 
pressure heaters and by the condensate taken from the low pressure condensate line. The energy 
efficiency and power upgrades of proposed methods is evaluated and compared. The highest increase 
of power plant efficiency is achieved by the flue gas cooling by the feedwater taken from the feedwater 
pump discharge line. This solution was implemented within the first phase of power plant overhaul, with 
a reduction of the flue gas temperature for more than 20 
oC and the boiler and power plant efficiency 
increases of approximately 2 and 0.53 percentage points respectively.",
publisher = "Institute of Thermal Technology, Gliwice, Poland, Silesian University of Technology",
journal = "Proceedings of the 5th International Conference on Contemporary Problems of Thermal Engineering Energy Systems in the Near Future: Energy, Exergy, Ecology and Economics, (CPOTE 2018), Gliwice, Poland, 19-21 September, 2018",
title = "Analysis of efficiency and power upgrades at the lignite-fired 2x620 MWe power plant by steam boiler waste heat utilization and different balance of plant modifications",
pages = "392-385",
url = "https://hdl.handle.net/21.15107/rcub_machinery_4526"
}

Stevanović, V., Petrović, M. M., Wala, T., Gajić, I.,& Muszynski, S.. (2018). Analysis of efficiency and power upgrades at the lignite-fired 2x620 MWe power plant by steam boiler waste heat utilization and different balance of plant modifications. in Proceedings of the 5th International Conference on Contemporary Problems of Thermal Engineering Energy Systems in the Near Future: Energy, Exergy, Ecology and Economics, (CPOTE 2018), Gliwice, Poland, 19-21 September, 2018
Institute of Thermal Technology, Gliwice, Poland, Silesian University of Technology., 385-392.
https://hdl.handle.net/21.15107/rcub_machinery_4526

Stevanović V, Petrović MM, Wala T, Gajić I, Muszynski S. Analysis of efficiency and power upgrades at the lignite-fired 2x620 MWe power plant by steam boiler waste heat utilization and different balance of plant modifications. in Proceedings of the 5th International Conference on Contemporary Problems of Thermal Engineering Energy Systems in the Near Future: Energy, Exergy, Ecology and Economics, (CPOTE 2018), Gliwice, Poland, 19-21 September, 2018. 2018;:385-392.
https://hdl.handle.net/21.15107/rcub_machinery_4526 .

Stevanović, Vladimir, Petrović, Milan M., Wala, Tadeusz, Gajić, Ivan, Muszynski, Sławomir, "Analysis of efficiency and power upgrades at the lignite-fired 2x620 MWe power plant by steam boiler waste heat utilization and different balance of plant modifications" in Proceedings of the 5th International Conference on Contemporary Problems of Thermal Engineering Energy Systems in the Near Future: Energy, Exergy, Ecology and Economics, (CPOTE 2018), Gliwice, Poland, 19-21 September, 2018 (2018):385-392,
https://hdl.handle.net/21.15107/rcub_machinery_4526 .

TY  - CONF
AU  - Bakić, Gordana
AU  - Đukić, Miloš
AU  - Rajičić, Bratislav
AU  - Šijački Žeravčić, Vera
AU  - Gajić, Ivan
AU  - Prodanović, Andrej
AU  - Maslarević, Aleksandar
AU  - Milošević, Nenad
PY  - 2016
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/4433
AB  - Toplotno postojani martenzitni čelik X20CrMo12 1 je našao široku primenu na domaćim termoenergetskim (TE) postrojenjima za izradu izlaznih sekcija pregrejača cevnog sistema kotla, kao i debelozidih komponenti kao što su kolektori izlaznih pregrejača i parovodi sveže pare. Dugotrajne karakteristike ovog čelika su detaljno istraživane i najvećim delom razjašnjene i kao toplotno postojani čelik spada u klasu najkvalitetnijih čelika do sada napravljenih. Međutim, pored svih prednosti glavni nedostatak ovog čelika je njegova loša zavarljivost. Zavarivanje na licu mesta, martenzitnih čelika je uvek veliki izazov i vrlo je teško dobiti kvalitetan zavareni spoj u kratkom vremenskom periodu, koliko recimo traju nepredviđeni zastoji bloka. U ovom radu je, radi poređenja, data karakterizacija tri zavarena spoja cevi pregrejača izrađenog od čelika X20CrMoV12 1, zavarena različitim tehnologijama zavarivanja: fabrički spoj dobijen zavarivanjem varničenjem, sa srodnim dodatnim materijalom i sa austenitnim dodatnim materijalom.
C3  - International Conference "Power Plants 2016" 23rd – 26st November 2016 Zlatibor, Srbija
T1  - Karakterizacija zavarenih spojeva cevi od čelika X20CrMoV121 dobijenih različitim tehnologijama zavarivanja
UR  - https://hdl.handle.net/21.15107/rcub_machinery_4433
ER  - 

@conference{
author = "Bakić, Gordana and Đukić, Miloš and Rajičić, Bratislav and Šijački Žeravčić, Vera and Gajić, Ivan and Prodanović, Andrej and Maslarević, Aleksandar and Milošević, Nenad",
year = "2016",
abstract = "Toplotno postojani martenzitni čelik X20CrMo12 1 je našao široku primenu na domaćim termoenergetskim (TE) postrojenjima za izradu izlaznih sekcija pregrejača cevnog sistema kotla, kao i debelozidih komponenti kao što su kolektori izlaznih pregrejača i parovodi sveže pare. Dugotrajne karakteristike ovog čelika su detaljno istraživane i najvećim delom razjašnjene i kao toplotno postojani čelik spada u klasu najkvalitetnijih čelika do sada napravljenih. Međutim, pored svih prednosti glavni nedostatak ovog čelika je njegova loša zavarljivost. Zavarivanje na licu mesta, martenzitnih čelika je uvek veliki izazov i vrlo je teško dobiti kvalitetan zavareni spoj u kratkom vremenskom periodu, koliko recimo traju nepredviđeni zastoji bloka. U ovom radu je, radi poređenja, data karakterizacija tri zavarena spoja cevi pregrejača izrađenog od čelika X20CrMoV12 1, zavarena različitim tehnologijama zavarivanja: fabrički spoj dobijen zavarivanjem varničenjem, sa srodnim dodatnim materijalom i sa austenitnim dodatnim materijalom.",
journal = "International Conference "Power Plants 2016" 23rd – 26st November 2016 Zlatibor, Srbija",
title = "Karakterizacija zavarenih spojeva cevi od čelika X20CrMoV121 dobijenih različitim tehnologijama zavarivanja",
url = "https://hdl.handle.net/21.15107/rcub_machinery_4433"
}

Bakić, G., Đukić, M., Rajičić, B., Šijački Žeravčić, V., Gajić, I., Prodanović, A., Maslarević, A.,& Milošević, N.. (2016). Karakterizacija zavarenih spojeva cevi od čelika X20CrMoV121 dobijenih različitim tehnologijama zavarivanja. in International Conference "Power Plants 2016" 23rd – 26st November 2016 Zlatibor, Srbija.
https://hdl.handle.net/21.15107/rcub_machinery_4433

Bakić G, Đukić M, Rajičić B, Šijački Žeravčić V, Gajić I, Prodanović A, Maslarević A, Milošević N. Karakterizacija zavarenih spojeva cevi od čelika X20CrMoV121 dobijenih različitim tehnologijama zavarivanja. in International Conference "Power Plants 2016" 23rd – 26st November 2016 Zlatibor, Srbija. 2016;.
https://hdl.handle.net/21.15107/rcub_machinery_4433 .

Bakić, Gordana, Đukić, Miloš, Rajičić, Bratislav, Šijački Žeravčić, Vera, Gajić, Ivan, Prodanović, Andrej, Maslarević, Aleksandar, Milošević, Nenad, "Karakterizacija zavarenih spojeva cevi od čelika X20CrMoV121 dobijenih različitim tehnologijama zavarivanja" in International Conference "Power Plants 2016" 23rd – 26st November 2016 Zlatibor, Srbija (2016),
https://hdl.handle.net/21.15107/rcub_machinery_4433 .

TY  - JOUR
AU  - Bakić, Gordana
AU  - Šijački Žeravčić, Vera
AU  - Rajičić, Bratislav
AU  - Radović, Miladin
AU  - Gajić, Ivan
AU  - Maslarević, Aleksandar
AU  - Jakovljević, Aleksandar
PY  - 2014
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/4590
AB  - Heat resistant martensitic steel X20CrMoV121 (DIN) is extensively used in the last few decades as a material for tubing systems and pipelines in thermal power plants. Long term behaviour of this material is well known and understood. X20CrMoV121 is found to be reliable for prolonged service at elevated temperatures. Main disadvantage is poor weld-ability, apart from other properties of great importance for tubing systems. Failure of the tubing system during service requires quick replacement of damaged parts. In situ repair welding of martensitic steels is always problematic since it requires special welding techniques usually difficult to perform in short time during forced outages. Here we report on the repair welding procedure for the outlet superheater in two 600 MW lignite power plant units. The super heater is made of X20CrMoV121 (DIN). Outlet temperature and pressure in the super heater system are 540°C and 18.6 MPa. The local thinning of tube walls is found to be the main damage mechanism of the super heater during prolonged service. Highly erosive lignite combustion particles are identified as the main reason for wall thinning.
A serious problem is the long required period for repair welding of damaged martensitic X20CrMoV121 steel. The solution was cold welding involving repair welding by austenitic electrode with high nickel and chromium content. This technique has many advantages as short welding time, no need for special atmosphere and preheating treatment, relatively easy welding process, etc. Repaired joints are usually replaced during next overhaul, but for investigation purposes some are maintained in service over 10 years. Intensive characterization of base and filler material of repair welds after 10 years service is reported in this paper.
PB  - Belgrade : DIVK
T2  - Integritet i vek konstrukcija
T1  - Characterisation of undermatch welded joint of X20CrMoV121 steel after prolonged service
EP  - 140
IS  - 2
SP  - 133
VL  - 14
UR  - https://hdl.handle.net/21.15107/rcub_machinery_4590
ER  - 

@article{
author = "Bakić, Gordana and Šijački Žeravčić, Vera and Rajičić, Bratislav and Radović, Miladin and Gajić, Ivan and Maslarević, Aleksandar and Jakovljević, Aleksandar",
year = "2014",
abstract = "Heat resistant martensitic steel X20CrMoV121 (DIN) is extensively used in the last few decades as a material for tubing systems and pipelines in thermal power plants. Long term behaviour of this material is well known and understood. X20CrMoV121 is found to be reliable for prolonged service at elevated temperatures. Main disadvantage is poor weld-ability, apart from other properties of great importance for tubing systems. Failure of the tubing system during service requires quick replacement of damaged parts. In situ repair welding of martensitic steels is always problematic since it requires special welding techniques usually difficult to perform in short time during forced outages. Here we report on the repair welding procedure for the outlet superheater in two 600 MW lignite power plant units. The super heater is made of X20CrMoV121 (DIN). Outlet temperature and pressure in the super heater system are 540°C and 18.6 MPa. The local thinning of tube walls is found to be the main damage mechanism of the super heater during prolonged service. Highly erosive lignite combustion particles are identified as the main reason for wall thinning.
A serious problem is the long required period for repair welding of damaged martensitic X20CrMoV121 steel. The solution was cold welding involving repair welding by austenitic electrode with high nickel and chromium content. This technique has many advantages as short welding time, no need for special atmosphere and preheating treatment, relatively easy welding process, etc. Repaired joints are usually replaced during next overhaul, but for investigation purposes some are maintained in service over 10 years. Intensive characterization of base and filler material of repair welds after 10 years service is reported in this paper.",
publisher = "Belgrade : DIVK",
journal = "Integritet i vek konstrukcija",
title = "Characterisation of undermatch welded joint of X20CrMoV121 steel after prolonged service",
pages = "140-133",
number = "2",
volume = "14",
url = "https://hdl.handle.net/21.15107/rcub_machinery_4590"
}

Bakić, G., Šijački Žeravčić, V., Rajičić, B., Radović, M., Gajić, I., Maslarević, A.,& Jakovljević, A.. (2014). Characterisation of undermatch welded joint of X20CrMoV121 steel after prolonged service. in Integritet i vek konstrukcija
Belgrade : DIVK., 14(2), 133-140.
https://hdl.handle.net/21.15107/rcub_machinery_4590

Bakić G, Šijački Žeravčić V, Rajičić B, Radović M, Gajić I, Maslarević A, Jakovljević A. Characterisation of undermatch welded joint of X20CrMoV121 steel after prolonged service. in Integritet i vek konstrukcija. 2014;14(2):133-140.
https://hdl.handle.net/21.15107/rcub_machinery_4590 .

Bakić, Gordana, Šijački Žeravčić, Vera, Rajičić, Bratislav, Radović, Miladin, Gajić, Ivan, Maslarević, Aleksandar, Jakovljević, Aleksandar, "Characterisation of undermatch welded joint of X20CrMoV121 steel after prolonged service" in Integritet i vek konstrukcija, 14, no. 2 (2014):133-140,
https://hdl.handle.net/21.15107/rcub_machinery_4590 .