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The results of the detailed investigations of behavior of lignites Kolubara and Kovin, in fluidized bed combustion are presented in the paper. Investigation was carried out due to the interest of the Serbian Electric Power Production Company to use CFBC boilers in the process of refurbishment of old pulverized coal combustion boilers. As a part of a feasibility study for CFBC use in power plants in Serbia, investigation of combustion characteristics of lignites was performed using original methodology introduced many years ago by Laboratory for Thermal Engineering and Energy. Methodology was approved by numerous investigations of more than 20 Yugoslav coals for FBC combustion, with the aim to determine design data for bubbling FBC boilers. The main attention in present investigation was paid to the problem of using methodology developed for bubbling FBC in the conditions present in CFBC boilers. Four samples of Kolubara lignite, with heat capacity from 2.5 to 8.5 MJ/kg, and different ash contents were investigated, and also lignite Kovin in the same range of heat capacity. Investigations were performed in three phases: (1) ultimate and proximate analysis, determination of ash sintering temperature by standard method and in fluidized bed laboratory oven, (2) investigations in laboratory fluidized bed furnace and determination of coal particle fragmentation, burning rate, start-up temperature and self-sulfure-capture and (3) investigation of combustion in pilot-plant in stationary combustion conditions. In conclusion, suitability of results obtained in BFBC conditions is approved, and earlier statement that lignites are suitable for BFBC is confirmed by the statement that lignites are even more suitable for burning in CFBC boilers. Considering differences between combustion and flow conditions in bubbling and circulating FBC boilers, behavior of the lignites in CFBC is discussed in details and optimal regime parameters of the CFBC boilers are determined. The results obtained will be used by Serbian Electric Power Production Company for evaluation of bid for CFBC boiler implementation in refurbishment of old thermal power plants.

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The electrostatic precipitator system of the lignite fired 350 MWe unit B1 of Thermal Power Plant Kostolac B has been modernized during 2014. The results of complex in site measurements, performed in the frame of performance control test at the beginning of the exploitation period of the upgraded electrostatic precipitator proved that, under normal and guarantee working conditions of the boiler and precipitator, the emission of particulate matter do not exceed limiting value. After the period of precipitator further adjustments, five series of measurements in the frame of acceptance test were performed in accordance with relevant standards. This paper presents results of the investigation of particulate matter concentration, laboratory analysis of the lignite, fly and bottom ash samples, working parameters of the unit and upgraded electrostatic precipitator as well as results of the calculations. The averaged mean particulate concentration at the exit of upgraded electrostatic precipitator of the unit B1 during Acceptance test was below guaranteed value. It is confirmed that adjustments of electrostatic precipitator electrical parameters have improved electrostatic precipitator efficiency, as well that electrostatic precipitatorcould work highly efficiently in energy save mode with lower power consumption.

This paper presents method for sustainability assessment of thermal power plant unit using multi-criteria analysis with aim to create base for business decision. Seven options of possible status of thermal power plant "Kolubara A" unit No. 2 with energy indicators of sustainable development were shown. Energy indicators of sustainable development consists of sets of resource preservation, economic, environmental, and social indicators. Sustainability assessment often fails to account for social influence on energy system. Considering to this, special focus will be on social indicators, their definition, forming, and impact on multi--criteria sustainability analysis. Analysis of quality of the selected options (energy systems) in respect to sustainable development by compare of their general index of sustainability is presented. Methodology of multi-criteria analyse of thermal power plant unit can show decision makers how to find best available options when the social indicators impact is leading. The aim of this paper is to choose the criteria for the evaluation of the available options, determine the relative importance of specific criteria and present methodology of multi-criteria analysis in the decision-making process.

The paper presents new experimental method developed and new measuring system developed and installed into flame-gas tract of utility boiler. Investigations have been performed at the steam boiler of unit 2 at TPP 'Ptolemais', Ptolemais, Greece, which suffered from very unstable combustion and great pressure oscillations. Experimental method, based on high-speed acquisition system, was developed and used for detection of pressure oscillations and determination of the origin of boiler unstable operation. Signals were obtained from piezoelectric pressure sensors located along the flame-gas tract of the steam boiler and time and frequency domain analysis were used for post processing of collected data. Investigations of the pressure oscillations in boiler gas tract have contributed to reveal origin of the boiler unstable operation, and have been of the great help in establishing proper boiler operation.

The anthropogenic emission of GHG especially CO has to be limited and reduced due to 2 their impact on global warming and climate change. Combustion of fossil fuels in the energy sector has a dominant share in total GHG emissions. In order to reduce GHG emission, European Union established a scheme for GHG allowance trading within the community, and the implementation of the European Union emission trading scheme, which is a key to GHG reduction in a cost-effective way. An important part of emission trading scheme is prescribed methodology for monitoring, reporting, and verification of the emission of GHG including characterization of the local fuels combusted by the energy sector. This paper presents lignite characteristics from open-pit mine Borovica-Pljevlja, which has highest coal production in Montenegro (>1.2 Mt per year), including evaluation of its carbon emission factor based on the laboratory analysis of 72 coal samples. Testing of the samples included proximate and ultimate analysis, as well as, net calorific value determination. In accordance with the obtained results, linear correlations between net calorific value