Sesija: Eksploatacioni problemi termo/hidro/vetro i drugih elektrana
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
nazad na Sesije
Marija Gajević, Milada Pezo (University of Belgrade, VINCA Institute of Nuclear Sciences, Laboratory for Thermal Engineering )
Vladimir Stevanović (University of Belgrade, Faculty of Mechanical Engineering)
Abstrakt
In this paper, a two-fluid model for the numerical analysis of thermal-hydraulic effects on the secondary side of the vertical steam generator is presented. The developed model is based on mass, momentum and energy balance equations for each phase in the two-phase mixture, both vapour and liquid, with closure laws used for modelling of interface processes. Numerical analysis is being performed using the FORTRAN programming language. In the scope of this model-development lies an accurate modelling of wall-fluid drag force between the two-phase mixture, under the conditions of transverse flow, and tubes in a bundle in vertical steam generator, for which different modelling laws are presented. It is acknowledged that precise modeling of the wall-fluid drag force, especially under the conditions of transverse flow across tube bundle, can lead to obtaining a more accurate pressure distribution on the shell side of steam generator, which is crucial for maintaining the integrity of the steam generator. Therefore, the accent is on obtaining the accurate pressure distribution in the vertical steam generator. The obtained results are compared with measured data, available in the literature. The developed model serves as a support for further design improvements of vertical steam generators.
Dragan Miljanović (Thermal Power Plant UGLJEVIK, Bosnia and Herzegovina, Republika Srpska)
Predrag Stefanović, Milić Erić, Zoran Marković (Belgrade University, VINCA Institute of Nuclear Sciences, Laboratory for Thermal Engineering)
Goran Rikić (Thermal Power Plant UGLJEVIK, Bosnia and Herzegovina, Republika Srpska)
Abstrakt
Electrostatic precipitator system (ESP) of the unit 300 MWe of Thermal Power Plant Ugljevik started operation in 1985 and so far it has been operating over 150.000 hours. In the previous period, no significant reconstruction of ESP was carried out except replacement of emission electrodes. As a consequence, failure of certain electrical components as well as mechanical damage on the internal elements of the ESP frequently occurred while particulate matter concentration at the exit of ESP was over 1000 mg/Nm3. In order to reduce particulate matter emission according to EU Directive 2001/80 and to improve availability of the facility, management of Thermal Power Plant Ugljevik decided to proceed with the reconstruction or replacement of the existing ESP with modern high-efficiency and reliably ESP. Compared to guaranteed dedusting efficiency of 99,693% and emission <150 mg/Nm3 for the original ESP design, the contractual requirements for the new ESP are set to be better than 99,935%, allowing dust concentration downstream ESP to be less than 50 mg/Nm3.
During the 2017 a new ESP was built by Consortium ZVVZ-Enven Engineering a.s/ZK-Thermchem s.r.o. from Czech Republik. The original ESP design, consisted of two separate ESP chambers, each with active volume of 14m x 14.6 m x 14.6 m and containing 4 separated fields in 4 dedusting zones, have been changed by new ESP to one integral chamber construction of 16,5 m x 34,5 m x 17,92 m active volume, with 15 electrical fields in 4 dedusting zones.
The series of complex measurements were performed in the frame of Performance Test and obtained results were used in the purpose of the new ESP optimization and adjustment. Thereafter, the Laboratory for Thermal Engineering and Energy, Institute of Nuclear Sciences Vinča carried out three series of measurements within Guarantee Tests A in order to verify the contractually guaranteed values of dust concentration downstream new ESP, pressure and temperature drop across new ESP as well as precipitation efficiency of new ESP. During the measurements, the coal quality was very good which is reflected in higher than guaranteed value of lower calorific value, higher total carbon and hydrogen content and lower ash content. The unit was operated with high pressure water heaters off resulting in lower temperature of the water at the inlet of the boiler and lower temperature of the flue gas at the air heater exit. This situation was in favor of high dedusting efficiency and low particulate emission at the exit of the new ESP. In the same time, new ESP was normally operated according to operational instructions, but one electric field in the zone 1 was out of order while secondary current in other fields was limited to values lower than nominal ones, which significantly deteriorated dedusting efficiency.
This paper presents the technical characteristics of old and new ESP design, results of Guarantee Tests A measurements, laboratory analysis of the coal, fly and bottom ash samples, comparatively to the guaranteed ones, working parameters of the unit and upgraded ESP during the measurements as well as results of the calculations. Based on results of measurements and calculation, it was proved that under normal and guarantee working conditions of the boiler and ESP, the concentration of particulate matter in flue gases at the exit of upgraded ESP do not exceed value of 50 mg/Nm3, while ESP achieved dedusting efficiency just below guaranteed value of 99,935%.
Radojica Graovac, Dragomir Marković (Energoprojekt Entel plc, Bulevar Mihaila Pupina 12, 11070 Beograd Serbia)
Abstrakt
The use of unmanned aerial vehicles (UAVs) or popular drones is becoming
increasingly important in all areas of everyday life of people, as well as at power plants.
Drones provide close visual inspection both in the construction process and during the
exploitation and maintenance of plant facilities. They are giving the possibility of
generating thousands of images and videos of a high resolution of a particular facility
or medium in the distribution of fuel, power production, transport and distribution of
power, early fire detection at some specific plant facility (if thermal camera is applied)
and also security purposes providing data and information faster and better in line with
direct access by operational personnel to the work of outdoor, even indoor, facilities
and installations being monitored. Recorded details such as for example: the smallest
cracks, difficulties in fuel transportation, fire hazard or abnormalities at facilities
become crystal clear. The level of detail combined with the ability to view and re-record
images means that detailed inspections can be carried out to identify problematic
areas, or regular maintenance requests. Flying a drone outside or inside the plant
facilities requires experience and skill. Use a drone outside plant requires the pilot and
program of flight to be certified by the Civil Aviation Directorate. On the other hand,
drones are potential tool, coming as an intruder, operated by vandals or terrorist groups
to endanger the security of plant facilities and staff working on them, including possible
attack to any of vital plant facility and even bringing complete plant to damage and to
stop operation. For this reason, the planning of airspace control devices around power
plant and associated facilities, including the planning of means for forced drones
landing is very important.
In this article are given in general the possible benefits of drone application at power
plants in Republic of Serbia as well as basic idea how can be established power plant
protection from drone attacks.
