Thermal / hydro / wind and other Power Plants exploitation problems

3-D NUMERICAL SIMULATION OF TWO-PHASE FLOW DURING SEPARATION PROCESS OF COAL POWDER IN MILL INERTIAL SEPARATOR

Ognjen Stamenković (“Mihajlo Pupin” Institute, Belgrade, Serbia, ognjen.stamenkovic@pupin.rs ) prof. dr Titoslav Živanović (Faculty of Mechanical Engineering, Belgrade, Serbia, tzivanovic@mas.bg.ac.rs) prof. dr Dragan Tucaković (Faculty of Mechanical Engineering, Belgrade, Serbia, dtucakovic@mas.bg.ac.rs) dr Goran Stupar (Faculty of Mechanical Engineering, Belgrade, Serbia, gstupar@mas.bg.ac.rs)

Sesija
: Eksploatacioni problemi termo/hidro/vetro i drugih elektrana
Poslao: Ognjen-Stamenkovic

Abstrakt In this paper, results of simulation of two-phase flow, gas phase and coal particles, within inertial mill separator are presented. Considered separator N 400.42 is integral part of coal powder preparation facility in thermal power plant “Nikola Tesla” B. Alteration of mass flow, granulation of recirculated coal particles and circulation number are given according to considered positions of regulation flaps. Calculation domain corresponds to real geometry of inertial separator integrated in considered thermal power plant. Selection of numerical grid has been performed on the basis of results of optimization of generated cells number, convergence time period according to previously stated criterias and characteristic quality parameters of obtained grid. For solving turbulent flow of gas (carrier) phase Oiler approach and standard k-ε turbulent model is used. Integrated Lagrange DPM model is applied for modeling momentum of monodispherse particles of coal powder within gas phase streamflow. In purpose of determining particles arrangement in inlet cross-section of mill separator, results of flow measurements and particle mill finesse gathered in outlet cross-section, air-mixture channel, have been used. Smulations have been performed iterativly, with changing particles disposition in inlet cross-section until the equivalence with measured values in outlet cross-section is achieved. Subsequently, simulations for different regulation flaps positions are performed. Beside character of gas phase flow and trajectories of representative coal particles within separator, results of simulations show fractions of particles in recirculation channel cross-section as well as inflection of inertial separator circulation number in dependency of regulation flaps positions. With aim of better understanding of two-phase flow stream, exposed inflections of modified parameters as result of performed analysis, may assist in defining the directions of influence on coal particles fractions in outlet cross-sections, with additional attention on fractions of particles introduced to recirculation channel of considered separator.

IMPORTANCE, CHARACTERISTICS AND MATHEMATICAL MODELING OF PROCESSES DURING CO-FIRING BIOMASS WITH PULVERIZED COAL IN FURNACES

Aleksandar R. Milićević (University of Belgrade, Vinca Institute of Nuclear Sciences, Mike Petrovica Alasa 12-14, P.O. Box 522, Belgrade 11001, Serbia) Srđan V. Belošević (University of Belgrade, Vinca Institute of Nuclear Sciences, Mike Petrovica Alasa 12-14, P.O. Box 522, Belgrade 11001, Serbia) Ivan. D. Tomanović (University of Belgrade, Vinca Institute of Nuclear Sciences, Mike Petrovica Alasa 12-14, P.O. Box 522, Belgrade 11001, Serbia) Nenad Đ. Crnomarković (University of Belgrade, Vinca Institute of Nuclear Sciences, Mike Petrovica Alasa 12-14, P.O. Box 522, Belgrade 11001, Serbia) Dragan R. Tucaković (University of Belgrade, Faculty of Mechanical Engineering, Kraljice Marije 16, 11120 Belgrade 35, Serbia)

Sesija
: Eksploatacioni problemi termo/hidro/vetro i drugih elektrana
Poslao: aleksandartta

Abstrakt The main motivation for co-firing coal with biomass is to reduce CO2 emissions as the so-called greenhouse gas (because of the greatest impact on global warming), but may also contribute to reduction of nitrogen and sulfur oxides, depending on composition of the fuel. This method also contributes to increasing the use of biomass as a renewable energy source. The complexity of the flow and installation, lack of measurement equipment and costs of experiments, often make it impossible, or difficult to perform experimental tests. Because of that mathematical models are developed based on theoretical considerations of physical processes and chemical reactions as well as empirical values from the literature and experimental tests. The first section of the paper presents the theoretical considerations and notes related to the issues and problems of co-firing coal and biomass. Then, review articles of CFD modeling processes of co-firing biomass with pulverized coal are shown. In modeling, similarity between the pulverized coal and biomass combustion can be assumed, despite significant differences in mechanisms and kinetics due to the diversity of biomass as a fuel and insufficient knowledge of the key characteristics of combustion. It should be mentioned that, the techno-economic analysis must be also kept in mind, taking into account all relevant costs and calculation of the main economic parameters, and justifying the introduction of biomass into the process of co-firing.

BASIC TECHNICAL CHARACTERISTICS OF 350 MW UNIT TPP "BANOVIĆI"

Mirza Dzindo (Termoelektrana Banovići , BiH)

Sesija
: Eksploatacioni problemi termo/hidro/vetro i drugih elektrana
Poslao: mirza

Abstrakt The paper contains a short presentation of technical characteristics of 350 MW unit TPP Banovici with an especial attention to De-SOx system. More details are dedicated to the elaboration of specifics of adopted technical solutions at this 350 MW unit, such as following: - Supercritical steam parameters - Combustion technology at circulating fluidized bed - Additional technical solutions for the unit efficiency increase - Closed cooling water system with natural draft cooling tower - Release of cleaned flue gas to atmosphere throughout cooling tower - Adopted two stage desulfurization - Use of bag filters for flue gas cleaning - Possibility of later installation of De-NOx system (NSCR) - Moisturized ash transportation tubular lent conveyor - Steam extraction for district heating of the town and neighboring places Main reason for selection of the above mentioned technical solutions is determination of investor to install one unit which would fulfill all requirements, rules and standards defined within “BAT Reference Document for Large Combustion Plant”, “Industrial Emission Directive 2010/75/EU” etc..

RECONSTRUCTION OF VIBRATORY SIEVES DRIVES IN SYSTEM FOR SEPARATION BOILER ASH FROM SLAG ON THERMAL POWER PLANT "TENT-B"

Zeljko V Despotovic (Mihajlo Pupin Institute, University of Belgrade, Serbia) Aleksandar M Pavlovic (Institute “Mihajlo Pupin” - ProjektInženjering, Belgrade, Serbia )

Sesija
: Eksploatacioni problemi termo/hidro/vetro i drugih elektrana
Poslao: zeljkodespotovic

Abstrakt This paper presents the new reconstructed and realized regulated AC drive of vibratory sieves, which are used for separation the boiler ash from the bottom-ash (slag), on thermal power plant TENT-B, Obrenovac in Serbia. The proposed technical solution is provided for adjustment of vibratory sieving parameters: frequency and amplitude of oscillations, as well as the angle of direction of the driving force relative to the grid of vibrating sieves. The frequency of oscillations is set by speed regulation of the unbalanced vibratory exciters, each driven by three-phase 2.2kW asynchronous motors. It is obtained the synchronous operation of vibration exciters, and the operation of vibratory sieves in super-resonant regime. In the paper are presents the experimental results and amplitude-frequency (AF) characterization of the vibrating sieves. These results are obtained during exploitation of vibratory sieves within the system for the separation the boiler ash from the slag.

CHARACTERISTICS OF FLY ASH FROM THERMAL POWER PLANTS IMPORTANT FOR HANDLING AND STORAGE SYSTEMS DESIGN AND ITS UTILIZATION

Nikola Karličić (University of Belgrade, Faculty of Mechanical Engineering) Aleksandar Jovović (University of Belgrade, Faculty of Mechanical Engineering) Dejan Radić (University of Belgrade, Faculty of Mechanical Engineering) Marko Obradović (University of Belgrade, Faculty of Mechanical Engineering) Dušan Todorović (University of Belgrade, Faculty of Mechanical Engineering) Miroslav Stanojević (University of Belgrade, Faculty of Mechanical Engineering)

Sesija
: Eksploatacioni problemi termo/hidro/vetro i drugih elektrana
Poslao: nikola.karlicic

Abstrakt Power plants in Serbia, based on high mineral contents coal usage, produce huge volumes of fly ash. Variation in coal quality is known to be related to quantities and composition of fly ash that is to be deposited. Fly ash characteristics are the most important precursor to design of handling and storage systems, as well as indicator for many possibilities on different reutilization. More and more thermal power plants are switching to sophisticated pneumatic conveying systems and storing dry fly ash, not only because of environmental aspects, but due to high demands for this kind of by-product. All of the above determines fly ash as a product which characteristics have to be known, what requires continuous investigations and detailed analysis. This paper attempts to highlight significant fly ash characteristics important from aspect of selecting adequate and reliable handling systems and utilization of fly ash in various industrial branches. Several trials on series of fly ash samples was carried out in Laboratory for Process Engineering - Faculty of Mechanical Engineering in Belgrade. Among other analysis it was determined bulk density, particle density, average diameter, porosity, minimum fluidization velocity, permeability and chemical composition. Also, a classification for obtaining guidelines for pneumatic conveying system selection was made.

IMPORTANCE OF DYNAMIC STRUCTURAL ANALYSIS ON THE CASE DESIGN OF EQUIPMENT FOR THE PREPARATION OF BURNING COAL IN THERMAL POWER PLANTS

M. Lazić (Energoprojekt – Entel, Belgrade, Serbia) D. Mitrović (Energoprojekt – Entel, Belgrade, Serbia)

Sesija
: Eksploatacioni problemi termo/hidro/vetro i drugih elektrana
Poslao: lazic1990

Abstrakt The paper deals with the importance of applying the structural dynamic analysis on the case of a system for crushing of coal for combustion in thermal power plants (with or without previous screening). The designer comes up to a solution i.e. design of the plant, taking into account the necessary project parameters, performing analysis and making some assumptions. It may turned out after the construction of the plant and exploitation of equipment, that the parameters are incorrectly assessed or being changed in the meantime. Therefore uncommon cracks, and even failures of the equipment itself and its supporting structure may occure. By comparing the results obtained by the dynamic structural analysis (finite element method) with the actual results of vibration measurements in exploitation, one may act preventively, both in terms of accident prevention and life cycle extension as well as in terms of reducing maintenance costs.

CHARACTERIZATION OF TUBE WELDS MADE OF X20CRMOV121 STEEL OBTAINED BY DIFFERENT WELDING TECHNOLOGIES

Gordana M. Bakic (University of Belgrade, Faculty of Mechanical Engineering, Kraljice Marije 16, Belgrade 11120, Serbia) Milos B. Djukic (University of Belgrade, Faculty of Mechanical Engineering, Kraljice Marije 16, Belgrade 11120, Serbia) Bratislav Rajicic (University of Belgrade, Faculty of Mechanical Engineering, Kraljice Marije 16, Belgrade 11120, Serbia) Vera Sijacki Zeravcic (University of Belgrade, Faculty of Mechanical Engineering, Kraljice Marije 16, Belgrade 11120, Serbia) Ivan Gajić (TPP TENT, Unit B, Obrenovac, Serbia) Andrej Prodanović (TPP TENT, Unit B, Obrenovac, Serbia) Aleksandar Maslarevic (Innovation Center of Faculty of Mechanical Engineering, Kraljice Marije 16, Belgrade 11120, Serbia) Nenad Milosević (University of Belgrade, Faculty of Mechanical Engineering, Kraljice Marije 16, Belgrade 11120, Serbia)

Sesija
: Eksploatacioni problemi termo/hidro/vetro i drugih elektrana
Poslao: gbakic

Abstrakt The heat resistant tempered martensite steel X20CrMoV121 (DIN) has been extensively used as a material for outlet superheater section of boiler tubing systems, headers and fresh steam pipelines in thermal power plants (TPP). Long-term behavior of this steel is vastly researched and very well known, and is qualifed to be one of the best heat resistante steel made till now. Nevertheless, main disadvantage is its poor weldability. In situ welding of martensitic steels is always challenging task and is usually quite difficult to implement properly in a short time, during forced outages of TPP. In this paper, characterization of welded joints made by differente welding techniques on TPP boiler outlet superheater (SH) tubes are presented. In the purpose of comparison three differente technologies were compared: shop welded joint made by electrical resistance flash butt welding, field welded joint made by gas tungsten arc welding, and welded joint with austenitc filler material.

VERIFICATION OF ON-LINE COAL ANALYZER MEASUREMENTS

Vladimir V. Jovanović (University of Belgrade, Faculty of Mechanical Engineering, Belgrade, Serbia) Nebojša G. Manić (University of Belgrade, Faculty of Mechanical Engineering, Belgrade, Serbia) Dragoslava D. Stojiljković (University of Belgrade, Faculty of Mechanical Engineering, Belgrade, Serbia) Vladimir Šestović (Electric Power Industry of Montenegro, TPP Pljevlja, Pljevlja, Montenegro)

Sesija
: Eksploatacioni problemi termo/hidro/vetro i drugih elektrana
Poslao: VladimirJovanovic

Abstrakt On-line coal analyzers are devices that perform real-time measurement of key data of coal proximate analysis, total moisture and ash content. In addition to these data, specific models have the option of calculating the heating value of coal based on empirical correlations between measured values of above mentioned proximate analysis data and heating value of coal. On-line coal analyzer ENELEX type GE 3000.CM was installed in TPP Pljevlja in 2014. for quality control of coal delivered from coal mine Pljevlja. After initial experiences in the operation of this device, a need to verify the results of its measurements arised, and based on the request of TPP Pljevlja, Fuel and Combustion Laboratory of the Faculty of Mechanical Engineering, University of Belgrade has carried out this verification. Entire work was performed in close cooperation and with assistance of technical personnel of coal mine Pljevlja and TPP Pljevlja. Verification was carried out fully in accordance with the international standard ISO 15239: 2005. Sampling of coal (for determination of proximate analysis data in the laboratory) from the conveyor belt was carried out in accordance with the international standard ISO 5069-1:1983. This paper presents the main results obtained in the process of verification of measurements of on-line coal analyzer.

MAIN DIRECTIONS OF DEVELOPMENTS FOR CAPILLARY-POROUS HEAT EXCHANGERS OF NEW HEAT-REMOVING CLASS

Alexandar Genbach (Faculty of heat power engineering, University of Power Engineering & Telecommunications, Almaty, Republic of Kazakhstan) Nellya Jamankulova (Faculty of heat power engineering, University of Power Engineering & Telecommunications, Almaty, Republic of Kazakhstan) Vukman Bakić (Laboratory for Thermal Engineering and Energy, “Vinča” Institute of Nuclear Sciences, University of Belgrade, P.O. Box 522, 11001 Belgrade, Serbia)

Sesija
: Eksploatacioni problemi termo/hidro/vetro i drugih elektrana
Poslao: vukman

Abstrakt The required information is received and developed on the basis of fundamental studies of capillary-porous systems operating in the field of mass forces. Integral and thermohydraulic heat transfer characteristics were obtained depending on the pressure, heat flux, excess fluid, heating method, the material type, a method for supplying coolant, the kind of intensifier and other factors. The required information is used in the design, engineering calculations and operation of different energy installations of power plants. Controlling of a heat transfer allows to allocate new system in a separate heat-removing class. Heat exchange devices were designed to improve the reliability and efficiency, taking into account the environment. Explosion-proof capillary-porous box-shaped heat exchanger was considered and the engineering calculation is given for its limiting and operational characteristics.

ECONOMIC FEASIBILITY OF BUILDING UP BIOMASS CHP PLANT

Dejan Đurović (University of Belgrade, Institute of Nuclear Sciences ‘‘Vinca’’, Laboratory for Thermal Engineering and Energy, P.O. Box 522, 11001 Belgrade, Serbia) Milica Mladenović (University of Belgrade, Institute of Nuclear Sciences ‘‘Vinca’’, Laboratory for Thermal Engineering and Energy, P.O. Box 522, 11001 Belgrade, Serbia) Milijana Paprika (University of Belgrade, Institute of Nuclear Sciences ‘‘Vinca’’, Laboratory for Thermal Engineering and Energy, P.O. Box 522, 11001 Belgrade, Serbia) Branislav Repić (University of Belgrade, Institute of Nuclear Sciences ‘‘Vinca’’, Laboratory for Thermal Engineering and Energy, P.O. Box 522, 11001 Belgrade, Serbia) Dragoljub Dakić (University of Belgrade, Faculty of Mechanical Engineering, Innovation Centre, Kraljice Marije 16, 11120 Belgrade 35, Serbia)

Sesija
: Eksploatacioni problemi termo/hidro/vetro i drugih elektrana
Poslao: Dejan2016

Abstrakt In order to obtain a realistic picture of what is obtained by investing in renewable energy sources needs to be done detailed techno-economic analysis. Possibility of replacing fuel (gas/heavy fuel oil) for steam production in one domestic chemical factory, with the simultaneous production of electricity using CHP systems, using biomass as a primary fuel have been analyzed in the paper. For the purposes of technological process of production requires a saturated steam of 9 t/h and pressure of 3 bar, while the planned installed capacity of electrical part is 1.3 MWe. The paper presents the analysis of possible solutions of boiler plant, as well as part for the production of electricity, with the presentation of the budget price. In the paper was also performed detailed economic analysis, with discounted cash flow, which showed the justification of the whole project. A comprehensive SWOT analysis of the project was performed, which will serve to show the good and bad sides of the proposed project as well as numerous possibilities, opened up with its realization.

Sesija: Eksploatacioni problemi termo/hidro/vetro i drugih elektrana