Razvoj i primena tehničkih dijagnostičkih metoda i opreme za praćenje i vođenje procesa; unapređenje opreme sa aspekta procesa koji se u njima odvijaju; savremena organizacija proizvodnje, metode i sredstva održavanja opreme.
Radovi odabrani za sesiju Konferencije pod nazivom: Eksploatacioni problemi termo/hidro/vetro i drugih elektrana
Srđan Milić (University of Belgrade-Faculty of Mechanical Engineering, Belgrade, Serbia)
Milan Banjac (University of Belgrade-Faculty of Mechanical Engineering, Belgrade, Serbia)
Srećko Nedeljković (University of Belgrade-Faculty of Mechanical Engineering, Belgrade, Serbia)
Miloš Ranković (University of Belgrade-Faculty of Mechanical Engineering, Belgrade, Serbia)
Dejan Đukanović (University of Belgrade-Faculty of Mechanical Engineering, Belgrade, Serbia)
Milan V. Petrović (University of Belgrade-Faculty of Mechanical Engineering, Belgrade, Serbia)
Marija Stevanović (Electric Power Industry of Serbia, TPP Morava, Svilajnac, Serbia)
Gordana Novaković (Electric Power Industry of Serbia, TPP Morava, Svilajnac, Serbia)
Abstrakt
The condenser plant has a huge impact on the economy of steam turbine power plant. Deterioration of the operating parameters during the exploitation could lead to a significant lowering of electrical output and to increase the heat rate of thermal power plant. The detailed calculations of performance at different operating conditions have been carried out for condenser of Morava thermal power plant. Comprehensive testing of condenser was carried out and experimental data are compared with the numerical results. The effects of deviations in condenser behaviour on the main thermodynamic parameters and the overall economics of the power plant were calculated. The guidelines for operation of the condensation plants are given in the conclusion.
Filip Aždajić (Javno preduzeće „Elektroprivreda BiH“ d.d. – Sarajevo, Podružnica Termoelektrana „Kakanj“)
Šemsudin Hodžić (Javno preduzeće „Elektroprivreda BiH“ d.d. – Sarajevo, Podružnica Termoelektrana „Kakanj“)
mr. Armin Husika (Javno preduzeće „Elektroprivreda BiH“ d.d. – Sarajevo, Podružnica Termoelektrana „Kakanj“)
Abstrakt
Due to frequent forced outages of the unit 7 in TPP Kakanj caused by cracking of condenser tubes replacement of condenser tubes has been performed during the overhaul at the end of 2015. After replacement there were no registered forced stoppages of the block caused by cracking condenser tubes while condenser vacuum was considerably increased. Because of increased enthalpy difference available power of the unit was increased and specific heat consumption of unit was reduced.
The return on investment has been made because of reducing the number of forced outages caused by cracking and reducing of specific heat consumption condenser tubes and reducing of specific heat consumption because of increasing the vacuum.
The analysis of these elements has demonstrated complete justification of realized investment in a replacement of condenser tubes.
Miloš Ranković (University of Belgrade, Faculty of Mechanical Engineering, Belgrade)
Milan Banjac (University of Belgrade, Faculty of Mechanical Engineering, Belgrade)
Srdjan Milić (University of Belgrade, Faculty of Mechanical Engineering, Belgrade)
Srećko Nedeljković (University of Belgrade, Faculty of Mechanical Engineering, Belgrade)
Milan V. Petrović (University of Belgrade, Faculty of Mechanical Engineering, Belgrade)
Abstrakt
The goal of aerodynamic design of turbine is reaching a high value of its internal efficiency in terms of the implemented restrictions, which refer to the dimensions of the turbine, the techno-economic requirements and other influencing factors. This paper describes a method for the one-dimensional calculation of gas turbine with cooling, which is used for preliminary determination of stage number, their main aerodynamic parameters, which further enables determination of the main dimensions of the turbine flow path. The calculation procedure is based on a few iterative optimization procedures of aerodynamic parameters by different stages, in order to achieve a high efficeincy while keeping the rational dimension and the number of stage. Developed mathematical model was implemented in a computer program. In this paper, based on various input data, the program used to generate a preliminary design flow path of two different gas turbines. These results are representing validity of a method.
Mirjana S. Laković (Faculty of Mechanical Engineering, University of Niš , A. Medvedeva 14, 18000 Niš)
Milica Jović (Faculty of Mechanical Engineering, University of Niš , A. Medvedeva 14, 18000 Niš)
Jasmina Bogdanović-Jovanović (Faculty of Mechanical Engineering, University of Niš , A. Medvedeva 14, 18000 Niš)
Abstrakt
In order to ensure the proper and efficient operation of power plants, it is necessary that both, the heat source and heat sink are properly dimensioned, and the process is properly guided. In this case study, there is a long-standing problem in the operation of power plant’s cold end, due to the under-dimensioned steam condenser. This problem is getting worse with the inevitable rise in the temperature of cooling water in summer. This paper discusses the possibility of installing vapor-compression refrigeration cycle machine in recirculating cooling water circuit in order to maintain design parameters of the condenser. In that way, it would be possible to achieve required level of power production at an appropriate vacuum in the condenser, even during critical summer meteorological conditions.
Vladimir Stevanović (University of Belgrade, Faculty of Mechanical Engineering, Kraljice Marije 16, 11120 Belgrade)
Milica Ilić (University of Belgrade, Faculty of Mechanical Engineering, Kraljice Marije 16, 11120 Belgrade)
Željko Đurović (University of Belgrade, Faculty of Electrical Engineering, Bulevar kralja Aleksandra 73, 11120 Belgrade)
Jelena Popović (Intellectual property Office, Knjeginje Ljubice 5, 11000 Belgrade)
Abstrakt
At steam boilers in units B1 and B2 of Thermal Power Plant „Nikola Tesla B“ (TENT B1) an additional economizer was implemented during the first revitalization phase in 2012 (B1) and in 2016 (B2). This additional economizer is fed with feedwater via a separate feedwater line which is connected to the main feedwater pump discharge line. In this way, a larger part of the feedwater flows into the high pressure regenerative heaters (HPH) within the main feedwater line, while a smaller part of feedwater is lead into the additional economizer. The installation of the additional economizer leads to an increase of the unit efficiency of more than 0.5 percentage points, what enables generation of about 10MW of „green“ electical energy on the basis of utilization of the waste heat contained in the flue gasses. Beside these significant energy, ecology and financial effects, the installation of the additional economizer also enables primary and secondary regulation of the unit power. Therefore, an increase of feedwater mass flow rate through the additional economizer decreases the feedwater flow rate through the high pressure regenerative heaters. Consequently, the steam extraction after the expansion in the high pressure turbine and the steam extraction at the intermmediate pressure turbine decrease, what lead to an increase of the turbine power. At the same time, the parameters of fresh steam at the entrance in the high pressure turbine stay unchanged.
This paper presents the results of numerical simulation of the change of the power of unit TENT B1 and B2 via change of the feedwater flow through the additional economizer. The emphasis in modelling is places on: feedwater heating up in high pressere regenerative heaters (HPH), steam extraction from turbines, which is lead to HPH, and turbine power increase resulting from the increase of steam mass flow rate. The model includes thermohydraulic processes in HPH such as heating up of feedwater in heaters „bis“ by superheated steam extracted from the intermmediate pressure turbine, heating up of feedwater by condensation of steam extracted from the high pressure turbine and heating up of the feedwater by wett steam obtained by mixing of condensate and steam cooled in heaters „bis“, unsteady pressure change on the steam side of high pressure regenerative heaters and unsteady change of pipe and heater shell material.
Mathematical model is derived from the balance equations for mass and energy, which result in a system of differential equations of the first order for determination of distribution of feedwater temperature, wall temperature in all high pressure heaters and steam temperature in the heater „bis“ along the pipe as well as pressure on the steam side of HPH. Mass flow rates from turbine extractions are determined by taking into account hydraulic characteristics of the steamlines and the difference in pressures at the place of steam extraction and in HPH. System of differential equations is solved numerically by Runge-Kutta method for given initial conditions.
Vinko L. Babić (Faculty of Mechanical Engineering, Banja Luka, S. Stepanovića 71.)
Zdravko N. Milovanović (Faculty of Mechanical Engineering, Banja Luka, S. Stepanovića 71.)
Momir M. Samardžić (Thermal Power Plant “Ugljevik”, Ugljevik)
Jovan B. Škundrić (Faculty of Mechanical Engineering, Banja Luka, S. Stepanovića 71.)
Abstrakt
In exploitation of thermal energetic facility with pulverized coal combustion, optimization of the facility for pulverizing is of a high importance. Pulverizer is important part of thermal power plant which has direct impact on combustion process in furnace of the boiler. As the combustion process represents the essence of all loses in thermal energetic facility, optimization of pulverizing facility is very much important regarding energetic efficiency of the block as a whole and also regarding its impact on the environment.
With every significant change of coal quality it is necessary to perform the analysis of potential impact of that change on combustion process in the furnace. As a consequence of coal quality change, for the combustion process, the most significant ones are: quality of coal powder, disposition of coal powder by burner’s levels, temperatures of aero-mixture and its velocity at the exit of the burner. The impact of the combustion process on slagging of the furnace and soiling convective surfaces appears to be especially important. Stated changes, besides their dependence on certain coal quality indicators, also indicate significant interdependency. From the above, all the complexity of determining the closest to optimal working regime for pulverizing facility can be seen.
Optimizing of the pulverizing facility work shown in this paper implies certain measurements, analysis and tuning during its exploitation and also implies making sheet for boiler work regime. The goal is to determine optimal working regime for boiler and respectively for the block, for longer time period when roughly constant coal quality is expected. This kind of optimization has especial impact on increasing safety and availability of the boiler, and respectively of the block as a whole.
Milan B. Tasić (CAD-FEM pro, Belgrade)
Marko M. Tasić (CAD-FEM pro, Belgrade)
Ilija B. Čairović (JP EPS, TENT-A, Obrenovac)
Vlatko R. Radivojević (JP EPS, TENT-A, Obrenovac)
Aleksandar M. Vesković (JP EPS, TENT-A, Obrenovac)
Abstrakt
The drive shaft coal mills (with HAMMER AND the fan zone), are exposed to high temperatures. High temperatures are a result of the guidance of flue gases in the piece of coal zone used for its drying before grinding. Mechanical properties of the drive shaft wich is exposed to the elevated temperatures degrade significantly. Therefore around the shaft is mounted protective tubes with guidance of the forced airflow for their cooling. Using modern CFD and FEM numerical tools were made simulation of protective tubes working processes for drive shaft of the mill DGS 100S. The goal of the simulation was to determine the causes of high stress intensity in the structural elements of protecting tubes. Analysis showed that the dominant influence on this phenomenon have a thermal loads. This is especially pronounced in the front protecting tubes, in the welding zone that connect the tube wall and flange and around the openings for the circulation of cooling air. By varying the geometric shapes of the structural elements in numerical models of the protective tube led to the recommendations on how to decrease the intensity of thermal stress in critical areas.
Petar Tatomirović (JP EPS, Ogranak TENT, Obrenovac)
Nebojša Turnić (JP EPS, Ogranak TENT, Obrenovac)
Ivan Ristić (JP EPS, Ogranak TENT, Obrenovac)
Zoran Božović (JP EPS, Tehnički poslovi proizvodnje energije, Beograd)
Aleksandar Latinović (JP EPS, Tehnički poslovi proizvodnje energije, Beograd)
Abstrakt
The most important systems of the steam turbines at thermal power plants are protection system and turbine control system. Main function of protection turbine system is to stop the supply of steam into the turbine after an unplanned interruption of production, after activation of protective functions or after uncontrolled turbine overspeed. Fault of the turbine protection system can cause total damage of the turbine plant and it is necessary to test protection system constantly. Thermal power unit can be in constant operation, without overhaul, more than six months, making it difficult to test. The new DCS system (Siemens SPPA-T3000), which is implemented in the thermal power plant TENT B, allows turbine protection and control system functional tests during operation of unit.
In this paper are detailed implemented functional tests of turbine protection system, boiler feed water pump turbine protection system and low pressure bypass protection system. The paper presents also details about tightness tests of steam turbine control and stop valves. Tests are realized in the thermal power plant TENT B.
Aleksandar Milic (EFT - Rudnik i Termoelektrana Stanari d.o.o, Stanari, Republic of Srpska, BiH)
Abstrakt
Izgradnja TE Stanari je zapoceta je krajem 2012 godine, sa EFT grupom kao investitirom i kineskom kompanijom Dong Fang kao isporučiocem opreme i glavnim izvodjacem. Blok je sinhronizovan na mrežu prvi put 4. Januara 2016, nakon čega je usledio period probnog rada i dokazivanja performansi. Snaga bloka je 300 MW, a gorivo je lignit iz stanarskog basena toplotne moci 9100 kJ/kg. Specifičnost TE Stanari je sto su primenjene , za naše prostore, nove tehnologije koje se izmedju ostalog ogledaju u sagorevanju u cirkulacionom fluidizovanom sloju, vazdušno hladjenom kondenzatoru, vrećastom filteru dimnog gasa i savremenim konceptima tretmana otpadnih i procesnih voda, te njihovom ponovnom koriscenju. Jedan zahteva projekta je bio i uskladjenost sa direktivom evropske unije o emisijama stetnih materija 2001/80/EU, koja definiše limite od 200 mg/Nm3 za sumporne i azotne okside, kao i 30 mg/Nm3 za praskaste materije. Navedeni zahtevi su uspešno ispunjeni, bez dodatnih postrojenja za odsumporavanje i sistema za redukciju Nox us pomoć amonijacnih jedinjenja. Optimizacija sagorevanja, i parametara sloja su ključni faktori u ispunjenju normi emisija, uz zadržavanje visoke efikasnosti rada kotlovskog postrojenja.
Nenad Đ. Crnomarković (University of Belgrade, Vinča Institute of Nuclear Sciences, P. O. Box 522, 11001 Belgrade, Serbia)
Srđan V. Belošević (University of Belgrade, Vinča Institute of Nuclear Sciences, P. O. Box 522, 11001 Belgrade, Serbia)
Ivan D. Tomanović (University of Belgrade, Vinča Institute of Nuclear Sciences, P. O. Box 522, 11001 Belgrade, Serbia)
Aleksandar R. Milićević (University of Belgrade, Vinča Institute of Nuclear Sciences, P. O. Box 522, 11001 Belgrade, Serbia)
Abstrakt
A new method for the application of the zonal model of radiative heat exchange in the numerical investigations of the processes inside the pulverized-coal fired furnaces which consisted in serial performing of numerical simulations was described. When the numerical simulation is carried out for the first time, the TEAs were determined for the adopted values of the surface zone emissivities. During the computation of the numerical simulation, temperature of every surface zone was determined depending on the heat flow rate through the furnace wall, adopted thickness of the ash deposit layer, and thermophysical properties of the ash deposit layer and metal wall. After the completed numerical simulation, new values of the surface zone total emissivities were determined according to temperature and used to determine the new set of TEAs. The average values of the relative differences of the surface zone total emissivities decreased with the increase of the numerical simulation serial number. Other selected wall- and medium-related physical quantities decreased or showed oscillations with the increase in the numerical simulation serial numbers. The heat flow rate through the furnace walls almost constantly decreased with the increase in the serial number, which showed that the method provided convergent results.
