[en] The condensation turbine 13K with nominal power of 125 MW is an axial three-cylindrical machine with inter-level steam heating and a 5-level heating system. The turbine consists: high-pressure cylinder FT; medium-pressure cylinder MP and low-pressure cylinder LP. The 5th level vanes of the LP cylinder have Baumann reinforcement and they are bound in packages of ten vanes each. During the 1994 overhaul, the following examinations were carried out: examination without destruction with penetrant and magnetic flux. It was found out that there were some defects and cracks on the 5th and 6th level vanes of the LP-rotor and some of the stellite plates had come off completely or some smaller parts were missing. At the places where stellite parts were missing the basic material was eroded to a large extent. On the basis of the report all damaged and loose stellite plates were removed, i.e. 50% of the 6th level and 87% of the 5th level. The turbine has since operated in such a condition and it has worked for additional 15000 working hours. During this period the condition of the vanes has been monitored and some examinations and measurements have been undertaken. It has been established that the current technical condition of the rotating 5th and 6th level vanes of the LP-turbine, where the stellite plates had been removed, indicates that they are seriously damaged and an urgent replacement of the vanes is absolutely necessary. (Author)

[en] In the Control Room in which control and regulation is performed upon the overall process of electric energy production, the operator plays essential role as an ultimate decision factor, particularly in the states of emergency. From the Control Room the operator performs a real-time supervision and management of the production process thus introducing exquisite quality into the operating fitness maintenance, creating optimal conditions for uninterrupted and safe production. The engagements of the operator in the Control Room require mutual accordance of the anthropology-technical and bio mechanical characteristics with the psychophysiological attributes of the operator. Any command and signaling equipment mishandling may cause numerous unwanted consequences, leading to a production control system breakdown for the power plant. In order to achieve a balanced optimization in the system operation, such as appropriate working conveniences, protection, certain economic effects, etc. an ergonomic organization and arrangement of the Control Room working environment is required. Re existing working environment solutions of the kind in our milieu show outstanding deviations towards the anthropology-physiological and psychophysiological capabilities of the operator on duties of the kind, as well as towards the collocation of signaling and command facilities and other equipment units at the Control Room site - the reason being a lack of appropriate investigation before setup of the systems. Solution to this kind of problems is aimed to provide maximum functional capability, efficiency and safety to the Control Room operator's domain of activities, which will essentially improve the reliability of the entire energy production control system of a thermoelectric power plant. (Author)

[en] In 1997 for the first time the scientific institutes from Republic of Macedonia got the opportunity to take part in competition to realize the scientific-research activity, financed by European Union. In the area of energy it could be applied for programs TERMI and COPERNICUS. A research project is applied for the program INCO COPERNICUS 97, with participation of the following research institutes: Koppern Aufbereitungstechnik GMbH and Co.KG - Germany; ENTEGRO - Greek Company for Energy Technology - Greece; Mining Institute Skopje - Macedonia; Faculty of Mechanical Engineering, Skopje - Macedonia; Faculty of Technical Sciences, Bitola - Macedonia; Central Institute for work protection, Skopje - Macedonia; Faculty for Industrial Chemistry and Metallurgy - Bulgaria. This paper presents the aim of the research, expected results, methodology and distribution of work among the research institutes

[en] The Renewable Energy Technology Characterizations describe the technical and economic status of the major emerging renewable energy options for electricity supply. These technology characterizations represent the best estimates of the US Department of Energy (DOE) and the Electric Power Research Institute (EPRI) regarding the future performance and cost improvements expected for these technologies as a results of continuing research and development (R and D) and development of markets for renewable energy through the year 2030. (orig.)

[en] Recycling systems for solid waste materials are designed to reduce the amount of solid waste materials going to land fields. Through the Trash Separation Systems, clean municipal waste are reused in production of fuel pellets. Other waste streams such as coal fines, sawdust, wood chips, coke breeze and agricultural waste can be blended with these pellets along with a high thermal value binder and/or used motor oil to form a quality clean burning alternative fuel. (Author)

[en] Designing gas installation requires an excellent knowledge of the gas, gas equipment, technological conditions in which the gas should be used and finally the existing standards and regulations acknowledged by the authorized inspection services. It is understandable that beside the above mentioned it is also necessary to possess a solid knowledge od the designing skill in order to complete all important factors which would enable a top-quality product - gas installation project. The purpose of this work is to show the experiences gathered through the designing of gas installations until the present period and to assist the joining of other good designing organizations in the future process of the gasification of our country. (Author)

[en] In this paper, coal from Bitola basin has been investigated as one of the most important Macedonian coal district. Investigations show that it is about young lignite with a low performed process of carbonization, for what indirectly points the minimal devitrification of siliceous accompanied gels. Presented data from the technical, elementary and siliceous analyses of the combustible coal ashes, evidenced the following parameters: total moisture, ashes, total sulphur, combustible sulphur, evaporable substances and caloric value, being competent for recognition the possibility for their application. As coals with remarkable reactivity and ability for very fast oxidation, they have a dominant role in manufacturing electric energy, with its participation of 85%. The conclusion is that in the future, this raw material will be a general energetic resource as well. (Author)

[en] With the total installed capacity of 3 x 225 MW, the Thermal Power Plant 'Bitola' provides 75-80% of the generated electrical energy in Macedonia. Its exploitation period is directly connected to the coal reserves of the open pit mine 'Suvodol', where 1997 Inclusive, the rest of the coal reserves are 98.100.100 t. According with the Electric Power Co. of Macedonia programme for balanced electric power production, these reserves will be consumed in 2013 - 2014, i.e. even earlier, taking into consideration the increased power of the blocks I, II and III. After this period of time, an electricity shortage might happened, if the ways of defining and solving the strategy for energy development will not be find on time. With the Power Plant's revitalization, there are a real mining/technological possibilities for its exploitation period continuation. Mainly, this is aimed towards the geologic coal reserves in the Suvodol mine, as well as deposit 'Brod -Gneotino'. In this paper the basic mining/technological parameters of the above mentioned potentials, especially 'Brod - Gneotino', are analysed. Thus, the preliminary technic-economical parameters in respect to the exploitation possibilities of the two deposits will be given

[en] A mathematical model for computation of the combustion process of solid fuel in fluidized bed is presented in this work. Only the combustor part of the plant (the fluidized bed and the free board) is treated with this model. In that manner, all principal, physical presumption and improvements (upon which this model is based) are given. Finally, the results of the numerical realisation of the mathematical model for combustion of minced straw as well as the results of the experimental investigation of a concrete physical model are presented. (author)

[en] The first vapor compression refrigeration systems and the problems with the used refrigerants are discussed. A result of the research were CFC fluids which are nontoxic, nonflammable, stable and inert. The excellent characteristics of CFC were a good reason for an enlarged expanding use in other applications, such as aerosols, polyurethane foam, solvent etc. After the discovery that CFCs damage the protective ozone layer in the stratosphere, Montreal protocol is signed (1987), which foresees a cutback in the production and use of CFCs. The phase out in the production of aerosols, foams and solvents is very effective and fast, but in the refrigeration systems is very slow because of their complex requirements and conflict of interests. The newest regulations from UNEAP are: the ban in the production and use of CFCs from 01 January, 1996. The long life of CFCs in the atmosphere contributes to the greenhouse effect and increase the average temperature on earth. The effect is mainly caused by carbon dioxide emissions (50%), while the contribution of CFCs is about 20 to 25%. The well known companies offer on the market new alternative fluids for refrigeration systems, mainly HFC fluids, but their influence upon the environment is still not proved. We already have the lesson of history. (author)