Slavica Prvulovic

Results of research on the energetic and economic efficiency of the use of biomass for heating an agricultural farm

ABSTRACT In this article the authors present an example of an agricultural farm that produces wheat corn, soya, and other plants. After harvesting granular products, large amounts of plant remains (biomass) are used as biofuel at the boiler in order to heat the agricultural farm. We present the results of research of energetic characteristics and boiler efficiency of thermal power of 750 kW that serves for farm heating. At the boiler biomass is burned and the boiler is adapted for burning dead animals and other remains using liquid petroleum gas) as additional fuel. Biomass that is used as biofuel is wheat or soya straw. Using the straw as an alternative biofuel significant cuts are achieved on conventional fuel LPG. The annual expense of soya straw is 1,700 tons, from an area of 565 ha, or 1,970tons of wheat straw from an area of 660 ha. Expenses of gathering, transport and storage are approximately 0.021 €/kg. Economic validity of using biomass as an energent had been proven by the fact that using straw is six times cheaper than using LPG. The ecological significance of using the biomass is investigated.

The Analysis of Energetic and Economic Parameters During the Utilization of Corn Grain as a Fuel for Cereal Dryers

Due to the increase in price of fossil fuel, utilization of biofuel as a renewable type of fuel is getting more cost-effective. In this article, the research results of drying rice grain using corn grain and its waste as a biofuel are presented. Comparative tests were conducted using heating oil and biofuel. The testing was conducted on two batch grain dryers of the same type. The dryers were filled with 32 t of wet rice. In one dryer heating oil was used, and in the other ground corn grain was used as biofuel. Based on the results of the research it was established that using ones own corn from the farm, 60–65% of the financial means can be saved from drying the grain.

Analysis of the results of research on spray drying of starch suspension

The spray dryer is very often applied in chemical and food processing industries. This drying method includes suspension spraying with the contents about 30 to 65% of dried substance. The drying period in most cases is only several seconds. The drying agent is the warm air. A model of momentum, heat and mass transfer in the atomization swirler zone was proposed. To verify the model an extensive experimental investigation was performed on water evaporation at different initial air temperatures, feed rates, flow rates of the drying agent and different parameters of atomization and initial particle size distribution. Good agreement between experimental results and theoretical data was achieved. The model was verified experimentally on the basis of results of investigations on drying of a 40% mass solution of starch and water.

Some aspects of the use of solar energy in Serbia

ABSTRACT This article presents the aspects of solar radiation and the use of solar energy in Serbia. It also considers why Serbia does not use thermal conversion of solar radiation in spite of much greater potential comparing to the countries of the Western and Central Europe, which are leading in the use of solar energy. The low standard of living, low electricity prices, the low level of energy efficiency in all areas of energy use, lack of knowledge, and political decisions are the main causes of insufficient use of renewable energy sources in Serbia.

Analiza uštede energije izborom dobijanja materijala tehnologijama reciklaže ELV-a

Recycling of cars includes a variety of procedures, which allow obtaining products floricane materials (metals, plastics, rubber, glass), suitable for the production of new material goods. In the paper the analysis of the recycling of motor vehicles. Motor vehicle recycling industry contributes to sustainability, environmental protection and energy saving. Using recycled materials saves energy and natural resources. Recycling creates less air and water pollution than primary production of raw materials. Recycling saves storage space, create new jobs in companies engaged in the collection, production and distribution of raw materials.

Resource potential and scope of the use of renewable energy sources in Serbia

ABSTRACT This article shows the overview of renewable energy resources in Serbia, since many reseach shows that Serbia has great potential of RES (renewable energy source). It also has good conditions for electricity production and heat energy from renewable resources. The aim is to research and represent the development possibility of a country in a sector of a RES, uncovering proven potential of renewable energy, emphasizing that unused potential of RES, together with energy sector, will create great opportunities and conditions for new market. The scope of this study was to research the potential of RES which exists in Serbia, to identify those which are most promising for implementation and integration into country energy sector and substitution of fosil fuels.

Solar energy in Vojvodina (Serbia): Potential, scope of use, and development perspective

ABSTRACT In this article, the solar radiation in Vojvodina (a region which is located on the north of Republic of Serbia) is discussed. Its application up until now in this region and possible additional applications of solar energy in the future are reviewed. The aim of this work is to overview the energy and exploitation possibility in using solar energy in all of the segments of energy consumption of Vojvodina and to present to potential investors relevant base for future decision-making of application of these technologies.

Analysis of shape opening on the ring of the matrix biomass pellet press

This paper describes the technological process of pressing pulverized biomass and analyzed different forms and dimensions of the hole in the matrix pelleting presses depending on the type of raw material for molding. Matrices may be flat and annular, and forms openings on their conical, square, oval, and cylinder. Dimensions of the matrix along the length of the channel can be constant and variable. The opening of the mouth of the channel can be extended in order to avoid build-up of material at the entrance of the channel, i. e. to reduce the resistance of the material in the pressing. The ratio of the diameter and length of the channel to determine the degree of compression molding material. Also, the extension of the output section of the canal is intended to reduce the resistance of molding materials. Shapes and sizes of the channel on the surface of the rollers for compacting biomass depending on the type and condition of the raw material for molding. It was noted that certain types of plant material compressed differently and therefore require different structural characteristics matrix for pressing biomass.