Dragoljub Dakic

Development of a Boiler for Small Straw Bales Combustion

In terms of sustainable energy development in Serbia, as well as in the whole world, there is a growing need for using the alternative energy sources. Alternative energy sources are, in most cases, renewable: biomass, wind power, solar energy, hydro-power and geothermal energy. A need for the utilization of this kind of energy sources is dictated by the market, on one side, as well as by environmental protection, on the other. Prices of fossil fuels grow proportionally to the decreasing of fossil fuel reserves. Since available reserves of fossil fuels in Serbia, especially those of high quality, are relatively limited, this problem becomes even more emphasized. On the other hand, it is necessary to harmonize the energy production legislation and practice in Serbia with the directives of the European Union, in the sense of intensifying the utilization of renewable energy sources and thus reducing pollution and greenhouse effect formation. Biomass is one of key renewable energy sources (van Dam et al., 2007). This is the reason for the development of cheap thermal devices (boilers and furnaces) burning biomass from agricultural production, as quite available and cheap energy source. These devices could be used primarily in villages, small towns and small businesses processing agricultural goods (greenhouses, dairy farms, slaughterhouses, etc.). The devices could also find use heating schools, hospitals and other institutions. Boilers and furnaces should utilize baled biomass which has not been adequately used and should have complete combustion control. The most favorable combustion organization for this type of devices is based on the principles of burning of a cigarette. The development of these devices should be simultaneous with the solving of the problem of low ash melting temperature and damaging of boiler metal parts and walls. At the same time, environmental aspect of combustion should be kept in mind.

Development of the Technology for Combustion of Large Bales Using Local Biomass

In terms of sustainable energy development in Serbia, as well as in the whole world, there is a growing need for using the alternative energy sources. Alternative energy sources are, in most cases, renewable: biomass, wind power, solar energy, hydro-power and geothermal energy. A need for the utilization of this kind of energy sources is dictated by the market, on one side, as well as by environmental protection, on the other. Prices of fossil fuels grow proportionally to the decreasing of fossil fuel reserves. Since available reserves of fossil fuels in Serbia, especially those of high quality, are relatively limited, this problem becomes even more emphasized [1-3]. On the other hand, it is necessary to harmonize the energy produc‐ tion legislation and practice in Serbia with the directives of the European Union, in the sense of intensifying the utilization of renewable energy sources and thus reducing pollution and greenhouse effect formation.

Factors Affecting Primary Fragmentation During Combustion of Serbian Coals

A two-phase experimental method to establish primary fragmentation behavior of Serbian lignites is presented. The first phase was fragmentation quantification, and second was measuring temperature response of center of coal particle during devolatilization. A dynamic simulation model gave thermal properties of coal used. The influence of various factors such as original size of coal, bed temperature, and coal rank on fragmentation is presented and discussed. A new factor, ratio of coal volatile content and coal thermal diffusivity, as representative of heat and mass transfer processes inside of coal particle, has been introduced and its influence on fragmentation index was analyzed.Copyright

Potential of utilizing agricultural biomass for energy purposes within public-private partnerships

The paper presents a proposal for forming public-private partnerships in small towns or villages in Serbia, in order to use potential of renewable energy sources, help local economy and, possibly, help preventing village withering. The project comprises construction of thermal plants at the periphery of a small town or a village, fueled by baled biomass form neighboring fields, together with a small industrial zone next to it. The industrial facilities would include storage and processing of agricultural products. The operation of the industrial zone should be organized in a way that the plant is used for heating and industrial purposes alternately. An example of such heating facility is presented here, accompanied by a basic economic analysis.

Results of combustion of different waste fuel in fluidized bad

The sustainable development of the national energy sector implies the rational use of energy resources, use of RES, and waste management with satisfying environmental regulations. A way to simultaneously fulfill the above objectives is the utilization of low-calorific and waste materials, applying the technology of fluidized bed combustion (FBC). This paper presents experimental results of combustion of number of solid and liquid wastes, conducted on two installations: industrial demonstration (capacity up to 100 kW) and experimental FB boiler (capacity up to 500 kW). The furnace temperature distribution, the composition of flue gas at the exit of furnace, and the other combustion parameters of the fuels are given. On the basis of these results, an evaluation of the waste fuels FB combustion and possibility of utilization of their energy potential is given.