SESSION: Thermal, hydro, wind and other Power Plants | Eksploatacioni problemi termo, hidro, vetro i drugih elektrana
papers selected for Symposium Session titled: Thermal, hydro, wind and other Power Plants | Eksploatacioni problemi termo, hidro, vetro i drugih elektrana
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Milić Erić - Institut za nuklearne nauke Vinča, Laboratorija za termotehniku i energetiku , Dejan Cvetinović - Institut za nuklearne nauke Vinča, Laboratorija za termotehniku i energetiku , Zoran Pavlović - Institut za nuklearne nauke Vinča, Laboratorija za termotehniku i energetiku , Slobodan Đekić - Elektroprivreda Srbije , Predrag Stefanović - Institut za nuklearne nauke Vinča, Laboratorija za termotehniku i energetiku , Predrag Radovanović - Institut za nuklearne nauke Vinča, Laboratorija za termotehniku i energetiku , Dragoslava Stojiljković - Mašinski fakultet Univerziteta u Beogradu
title: PRIMENA METODE BRZE AKVIZICIJE ZA ISPITIVANJE PULZATIVNOG SAGOREVANJA U GASNOM TRAKTU PARNOG KOTLA BLOKA 2 NA TERMOELEKTRANI TPP “PTOLEMAIS”
Abstract text
Parni kotao bloka 2 termoelektrane TPP “Ptolemais”, Ptolemais, u Grčkoj, instalisane snage 125 MW, koji se u eksploataciji nalazio neprekidno skoro četiri decenije, u cilju produženja radnog veka kapitalno je remontovan, delimično rekonstruisan i modernizovan tokom 2000. godine. Pri tome, kotlu nisu menjani projektni kvalitet goriva (lignit), radni parametri, kao ni instalisana snaga.
Nakon završetka radova, javilo se dosta problema sa postizanjem nominalne produkcije pare i održavanjem stabilnog pogona kotla. Intenzivne i učestale pulzacije pritiska u njegovom plameno-gasnom traktu uzrokovale su značajnu nestabilnost plamena, što je rezultiralo dostizanjem svega 75% nominalne produkcije pare uz konstantnu podršku dodatnim tečnim gorivom.
U cilju rešavanja osnovnog problema, tj. stabilizacije procesa sagorevanja i dostizanja nominalne produkcije pare, odnosno nominalne snage bloka, izvršena su složena termotehnička ispitivanja u nastojanju da se odredi izvor nestabilnog sagorevanja, odnosno značajnih oscilacija pritiska u plameno-gasnom traktu kotla.
U radu su opisani primenjena merna metoda, merni sistem koji je razvijen i ugrađen u plameno-gasni trakt ispitivanog kotla, način obrade mernih rezultata kao i sami rezultati ispitivanja.
Merni sistem za karakterizaciju pulzacija zasnovan je na piezoelektričnim meračima – pretvaračima pritiska sa radnim opsegom ±5 kPa, a prikupljanje mernih podataka izvršeno je automatski sa učestanošću u opsegu od 100 Hz do 5 kHz, a najčešće oko 1 kHz.
Tokom ispitivanja, prikupljeno je, a kasnije obrađeno preko 20 miliona različitih mernih podataka, najviše o oscilacijama pritiska. Za analizu podataka o oscilacijama pritiska u plameno gasnom traktu kotla, odnosno za određivanje uzroka, intenziteta i frekvencije pulzacija korišćeno je nekoliko metoda u vemenskom i frekventnom domenu. Analize od vrha do vrha (peak-to-peak analyses) u vremenskom domenu pokazale su vreme kašnjenja između signala sa pretvarača postavljenih na različitim mernim mestima, na osnovu čega je određeno mesto nastanka pulzacija. Analize unakrsne korelacije (cross-correlation analyses) i brze Furijeove transformacije (Fast Fourier Transformation - FFT) korišćene su da bi se ispitivana pojava opisala u frekventnom domenu.
Rezultati kompleksnih ispitivanja nedvosmisleno su ukazali na uzrok poremaćaja u procesu sagorevanja u kotlu. Primenom odgovarajućih mera, pre svega podešavanjem rada mlinskih postrojenja, ložnih uređaja i ventilatora svežeg vazduha, problem je otklonjen, a blok je dostigao nominalnu snagu uz projektne parametre pri stabilnom, dugotrajnom radu.
G. Živković, S. Nemoda, P. Stefanović P. Radovanović - Institut za nuklearne nauke VINČA, Laboratorija za termotehniku i energetiku
title: NUMERICAL SIMULATION OF THE INFLUENCE OF THE STATIONARY LOUVER AND PARTICLE SIZE ON COAL POWDER DISTRIBUTION I N POWER PLANT BURNING CHANNELS
Abstract text
One of the key requirements for implementation of plasma system for oil free combustion support on power plant boilers is a regulation of coal powder distribution in burning channels, in order to achieve adequate concentration of coal powder in the zone where thermal plasma is introduced. This can be efficiently achieved by introduction of the stationary louver in the mixing channel in front of the burning channels. This paper deals with the numerical simulation of two phase flow of the air-coal powder mixture in the mixing channel, and analysis of the influence of the coal powder size on the powder mass distribution among burning channels. Numerical simulation was performed by FLUENT 6.3 commercial code. Results show considerable influence of particle size on the overall distribution. It also confirmed stationary louver as efficient tool for separating phases, through its stronger influence on discrete than on continuous phase flow profile.
G. Živković, S. Nemoda, P. Stefanović P. Radovanović - Institut za nuklearne nauke VINČA, Laboratorija za termotehniku i energetiku
title: NUMERICAL ANALYSIS OF THE INFLUENCE OF LOUVERS ON THE COAL POWDER DISTRIBUTION IN BOILER BURNING CHANNELS ON TENT-A6
Abstract text
The measurements performed in 2006 on a boiler of TENT-A1 showed that the distribution of the air-coal powder mixture over the burning channels is not appropriate, and that the amount of coal powder to the higher burners should be reduced. In order to achieve this a system of louvers were applied. This paper deals with the numerical simulation of two phase flow of the air-coal powder mixture in the domain where louvers were settled and in burning channels as well, as a prerequisite for the louver introduction. The emphasize was put on the analysis of the louver geometry characteristics and the louver inclination angle, as a mean parameters which determine powder distribution among the burners. Numerical simulation was performed by FLUENT 6.3 commercial code. It was concluded that louvers represent an efficient tool for the redistribution of coal mixture over the burning channels. Their mutual position is of the crucial importance in managing the coal powder flow. The separation distance between the louver blades at some extent influences the flow pattern, but does not represent dominant parameter, as well as the louver blade inclination angle.
prof. dr Branislav M. Savić, dipl. ing. - Mašinski fakultet, Univerziteta u Beogradu , ass. mr Radiša Jovanović, dipl. ing. - Mašinski fakultet, Univerziteta u Beogradu , prof. dr Zoran Ribar, dipl. ing. - Mašinski fakultet, Univerziteta u Beogradu , prof. dr Vladimir Stevanović, dipl. ing. - Mašinski fakultet, Univerziteta u Beogradu , Milorad Dobrosavljević, dipl. ing - Mašinski fakultet, Univerziteta u Beogradu
title: DEVELOPMENT OF A SOFTWARE SYSTEM FOR ON-LINE INSTRUCTIVE INTERVENTION FOR THE IMPROVEMENT OF STEAM POWER PLANT OPERATION
Abstract text
The development of this software system was realized through the project 213001 participated by the Ministry of Science of the Republic of Serbia under the National Program of Energy Efficiency. The software system is developed to provide information of instructive character, on the basis of existing operational state of the steam block, with the possibility of on-line interactive intervention in order to improve the process operation. It uses sampled data of the steam block operational state from the last observed period, obtained by our previously developed basic software system for the operation diagnosis of the steam power plant. The particular software subsystem, for the calculations of regime loads and performance parameters on the basis of existing operational state, enables to obtain the real information about the influence of process parameters on heat rate and load deviations necessary for the optimal instructive intervention. In this paper, presented are results of the simulation, obtained with the developed software system, which can be applied for the on-line instructive intervention. Also, some results obtained by the previously developed basic software system, for the operation diagnosis, are discussed in scope of the presented results.
Milada Pezo - Institut za nuklearne nauke VINČA, Laboratorija za termotehniku i energetiku , Vlada Stevanović - Mašinski fakultet, Univerziteta u Beogradu
title: NUMERICAL SIMULATION OF POOL BOILING PROCESS
Abstract text
Predictions of nucleate boiling mechanisms and burnout conditions are very important in thermal-hydraulic safety analyses in steam generators. Mathematical modelling and numerical simulation of these phenomena require a treatment of vapour-liquid two-phase mixture on the macro level, as well as on the micro level, such as bubble rise and departure at the heating surface. A mathematical model of pool boiling was developed in this paper, with water-steam as coolant. Three-dimensional two-phase flow is modelled by the two fluid model. Interface transfer processes are calculated by the closure laws. Numerical experiments have been performed under high heat fluxes, which lead to the boiling crisis. Boiling crisis occurs when the heated surface is covered with vapour bubbles, and these bubbles form a barrier that hinders the replenishment of the heated wall by the pool water. Under these conditions the wall dryout occurs. The thermal transient behaviour of the heated wall is also the subject of this paper. A large increase of the wall temperature is predicted in case of dryout occurrence.
I. Popović, M. Zlatanović - Faculty of Electrical Engineering University of Belgrade , Z. Gršić - Institute of Nuclear Sciences "Vinča"
title: PERFORMANCE OF SENSORS MOUNTED ON ISOLATED AND GRID CONNECTED WIND MAST
Abstract text
First and second-generation cup anemometers for wind speed measurements as well as non-mechanical anemometers like hot-wire anemometers were comparatively field-tested. The sensors for wind speed and direction measurement were mounted onto two 36m tall telecommunication towers, one 40m and one 50m wind mast, located in the same-targeted area. The measurements data taken from different sets of sensors placed on wind masts located on different terrain configurations provides us with the complete set of information for use in our analysis. Our analyses have shown that sensor characteristics are strongly influencing wind speed and wind direction measurements and that non-mechanical anemometers are less sensitive to icing and more accurate and reliable. Therefore, in application dependant on accurate and reliable data measurement, usage of more sophisticated measuring methods is recommended.
V. Turanjanin, V. Bakić - Institut za nuklearne nauke VINČA, Laboratorija za termotehniku i energetiku , N. Miloradović - PUC „Beogradske elektrane“, Savski nasip bb, 11070 Beograd, Srbija , B. Vučićević, M. Jovanović, M. Petrović - Institut za nuklearne nauke VINČA, Laboratorija za termotehniku i energetiku
title: SIMULATION OF COMBINED SYSTEM FOR WATER HEATING
Abstract text
A dynamic simulation was done for DHW production in the summer operating period. The
main objective of this paper was to evaluate projects energy benefits of the large-scale solar heating
connection to district heating system, for fossil fuels substitution of the hot water production for
domestic use during the summer period. Hot water for district heating and domestic use produces in
heating plant “Cerak” in Belgrade. The heating plant is placed at the suburb of the Belgrade and
supplying one settlement with hot water only during the summer period. There is exists production
and distribution system based on fossil fuel energy, mainly of the natural gas. In the first phase of
the project it was planned to install about 5000 m2 of solar collectors.
Marina Jovanović, Valentina Turanjanin, Vukman Bakić - Institut za nuklearne nauke VINČA, Laboratorija za termotehniku i energetiku , Bojan Bogdanović - PUC „Beogradske elektrane“, Savski nasip bb, 11070 Beograd, Srbija , Milada Pezo - Institut za nuklearne nauke VINČA, Laboratorija za termotehniku i energetiku
title: TECHNO ECONOMIC ANALYSIS FOR COMBINED HEAT ENERGY PRODUCTION SYSTEM ON HP CERAK LOCATION
Abstract text
In this paper analyzing possibilities of solar energy utilization for the purposes of hot water production in Heating Plant Cerak is performed. Heating plant ’’Cerak’’ is an integral part of PUC ’’Beogradske Elektrane’’ and it produces and delivers heat energy for heating and domestic hot water to customers in Belgrade municipalities of Cukarica and Rakovica. Basic fuel currently used in the plant is natural gas or fuel oil. According to the amount of heat necessary for water heating in the combined system from the boiler and collector and the amount of heat entering the boiler with the fuel (gas), simulation for the six months period (15 April-15 October) is done. Also, three cases when the part of produced heat energy in the combined system is obtained from the solar thermal system with a) Apricus type of collectors, b) NAU type of collectors and c) GJ type of collectors are shown. The pay out period has been calculated through sum of annual savings and their comparison to the total investment costs. Reduction in CO2 emission is calculated for summer operating mode (three operating mode: 62/45°C, 65/22°C, 60/40°C)
Nebojša Panjevac, Nikola Jevtović - IMP - Automatika, Beograd , Dragan Josipović - TE "Kostolac", Kostolac , Miroslav Crnčević - IMP - Automatika, Beograd
title: MODERNIZACIJA SISTEMA ZA NADZOR I UPRAVLJANJE BLOKA TE „KOSTOLAC“ B1 – 348,5 MW
Abstract text
Prikazani su osnovni razlozi za modernizaciju, projektovana rešenja, obim izvedenih radova i isporučene opreme sistema za nadzor i upravljanje, koju je realizovao Institut „Mihajlo Pupin“ – Automatika, Beograd u periodu obavljenog kapitalnog remonta bloka TE „Kostolac “ B1 snage 348,5 MW.
Abstract:
The paper describes the main reasons for modernization, with details on design solutions, the scope of delivered equipment and executed works on reconstruction of Measurement and Control System of Unit B1 in Thermal Power Plant „Kostolac“, with installed power of 348,5 MW, which was done by Institute „Mihajlo Pupin“ during Major Overhaul of the Unit.
Rastko Jovanović, Dejan Cvetinović, Predrag Stefanović, Zoran Marković, Zoran Pavlović - Institut za nuklearne nauke VINČA, Laboratorija za termotehniku i energetiku , Bartosz Swiatkowski - Thermal Processes Department, Institute of Power Engineering, Mory 8, 01-330 Warsaw, Poland
title: Turbulent Two-Phase Flow Modeling of Air-Coal Mixture Channels with Single Blade Turbulators
Abstract text
Subject of this work is turbulent two-phase flow through air-coal channel(s) of complex geometry. Air flow through all eight air-coal mixture channels was simulated in first stage. Velocity and pressure field were obtained as results of this simulation. One channel was selected, based on obtained results from first case. Two-phase flow was simulated in this channel. Lagrangian multiphase model was used for discrete phase (coal particles) modeling. Two-phase flow in air-coal mixture channel without turbulator was simulated next. After that, two-phase flow in air-coal mixture channels with two different turbulator heights was simulated. Turbulators were set parallel to velocity vectors at inlet. Finally turbulators were rotated for 12 deg. around x-axis in positive mathematical direction, and simulation was repeated for both turbulator heights.
The aim of this work is numerical optimization of fluid flow and coal particle distribution in reconstructed air-coal mixture channels. Single blade turbulator was used to increase turbulence in vertical section of air-coal mixture channel. Standard k-ω turbulent model was used for modeling turbulence. Lagrangian multiphase model was used for modeling coal particle distribution.
More uniform coal particle distribution has been achieved using single blade turbulators. Results show that there is no significant difference in coal particle distribution between all four cases in which different turbulator geometry and position was used. Upon these conclusions, technologically simplest solution, turbulator with low height, can be suggested.
Although better particle distribution is reached using single blade turbulators, particle concentration in evaluation section (where plasma generators will be built in) still remained anisotropic. Because uniform coal particle distribution is of great importance for proper work of plasma generators, other solutions for achieving this goal will be object of future analysis.
