Energija, ekonomija, ekologija

1-9

Authors: Nihad Hodžić, Kenan Kadić, Anes Kazagić

The thermal energy sector is very important at this time of global energy transition. From the aspect of stable energy independence, this is especially important in countries whose energy system is based on fossil fuels, especially coal. This is why decarbonisation of the energy sector is necessary, with a partial and gradual substitution of coal with renewable fuels. However, the use of these fuels is not always possible in existing plants. This refers to the establishment of energy, economic and environmentally acceptable proportion of the co-firing of these fuels, i.e. a mixture of coal and renewable fuels. The success of the establishment of this process is a function of several variables, the dominant of which are the aggregate properties of the fuel, basic and their mixtures, including the ash properties of those fuels. With the motive of contributing to a more successful implementation of the energy transition in the thermal energy sector, and with the aim of obtaining new scientific knowledge about the characteristics of the combustion of lignite and brown coal with different renewable fuels, laboratory research was carried out. In particular, different mixtures of lignite and brown coal, waste woody biomass and Miscanthus as a fast-growing energy crop were subjected to co-firing with variable process conditions. In addition to changing the composition of fuel mixtures, the test regimes included a significant change in process temperature (1250-1450 °C) and the primary measure of staged air supply to the furnace. In these combustion conditions, the emission of undesirable and harmful components into the environment, the efficiency of combustion, and the tendency of the ash from the fuel mixture to possible soiling of the heating surfaces in the furnace were evaluated - an analysis of the characteristics of the ash samples from the reaction zone and samples of the slag and ash to the furnace. Here, in both cases of co-firing, lignite and brown coal with different types of biomass, it was shown that in real conditions it is possible to establish a sustainable primary energy conversion process from fuel with a low unburnt carbon content in the slag (unburnt carbon content, UBC<1%) as well as low CO emission, below 350 mg/mn3. At the same time, the NOx emission is below 320 mg/mn3 during the co-firing of lignite mixtures at 1250 °C, and in the case of brown coal mixtures below 740 mg/mn3 at 1450 °C. In both cases, the net CO2 emission decreases in proportion to the proportion of biomass in the mixture, while the SO2 emission is still high, at a level of up to 2500 mg/mn3 for lignite mixtures and up to 6400 mg/mn3 for brown coal mixtures. None of the treated types of biomass, up to the level of applicable content in the mixture with lignite and brown coal, does not worsen the progress of the process from the aspect of possible slagging/fouling heating surfaces in the boiler.

17-23

Authors: Dejan Ivezić, Marija Živković

Final energy consumption in the industrial sector accounts for almost 25% of energy-related final energy consumption in the Republic of Serbia. It is estimated that 50-70% of energy consumption in industry, is intended to heat production in various industrial processes. Some of the produced heat is irreversibly wasted: through walls of process equipment, as the energy of flue gases, wastewater, etc. Utilization of waste heat for meeting heating needs, within or outside of an industrial facility, although possible and recommended, is a challenging task. Carriers of waste heat may be different (flue gases from the combustion process, liquid fluids from the washing, drying or cooling process, etc.), as well as their temperature range (from below 50°C to over 500°C.). Availability of waste heat is highly dependent on industrial processes, while potential consumers often may be distanced from an industrial site. The paper presents the results of the evaluation of waste heat potential for some industrial subbranches in Serbia, based on a previously developed methodology. Based on data about energy consumption in selected subbranches of industry, and the temperature of waste heat carriers, the theoretical potential of this alternative source for direct utilization or utilization by compression heat pumps in district heating systems is determined.

35-39

Authors: Aleksandar Nešović, Danijela Nikolić, Nebojša Lukić

Zbog svog zanimljivog arhitektonskog rešenja, podzemne zgrade Yaodong kao da nude balans između prirodnih i stvorenih parametara lokacije (s jedne strane) i ambijentalnog komfora (s druge strane). U prvom delu rada definisan je koncept Yaodong (vreme nastanka, geografsko poreklo, kategorizacija, prostorna organizacija enterijera, geometrijske karakteristike, itd.). U drugom delu, autori predstavljaju konkretan model podzemne konstrukcije Yaodong koristeći softver Google SketchUp. Zatim vrše simulaciju potrošnje finalne i primarne energije u zgradi koristeći EnergyPlus softver i vremensku datoteku za grad Kragujevac. Iako je ovaj tip gradnje karakterističan za severozapadnu Kinu, autori su mišljenja da pomenuti građevinski dizajn može biti i od nacionalnog značaja, pogotovo kada se u obzir uzme činjenica da je potrošnja finalne (i primarne) energije poslednjih godina na svom vrhuncu, što, između ostalog, važi i za stambeni sektor.

51-58

Authors: Aleksandar Mirković, Marija Živković, Stevan Đenadić, Darja Lubarda, Chinedu Anyanwa

Reducing greenhouse gas emissions is one of the main targets of national strategies in European countries. As a main contributor to emissions, the energy sector is recognized as the most promising to apply measures and actions aimed to decrease GHG emissions. The Oil and Gas industry as a significant contributor to global greenhouse gas emissions is facing a growing need for estimating, mitigating, and reducing the impact of their operations on the atmosphere to stay competitive in a newly arising green economy. The goal to reduce GHG emissions emphasises the need for identification of the main sources of emission in the Oil and Gas industry. This paper presents the comprehensive blueprint for the development of a greenhouse gas emissions inventory for complex industries such as Oil and Gas, including its specifics related to processes of Oil and Gas production and processing (flaring, fugitive emissions, etc.). The model is implemented for a case of a typical upstream oil and gas company, with the aim to identify the main sources of emission. It was shown that the major source of emission is gas flaring, while the key contributor is uncombusted methane.

67-73

Authors: Nikola Stanković

Planirani projekat predstavlja izgradnju kompleksa vetroelektrane Kostolca na prostorima spoljnih odlagališta i jalovišta u Kostolcu, nastala kao posledica rudarskih aktivnosti. Predviđeno je pozicioniranje 20 vetroelektana pojedinačne snage 3,3 MW, tako da je ukupna instalisana snaga 66 MW. Urađena je celokupna investiciona-tehnička dokumentacija koja obuhvata studiju o proceni uticaja projekta na životnu sredinu po nacionalnim zakonodavnim zahtevima kao i međunarodnu studiju o proceni uticaja na životnu sredinu i društvo po zahtevima Nemačke razvojne banke. U radu je data analiza uticaja buke u fazi izgradnje i eksploatacije vetroparka. Primenom mera datih kako u nacionalnoj tako i u međunarodnoj studiji efekti uticaja bukе biće minimizirani. Takođe, na osnovu modelovanja i analize intenziteta buke došlo se do zaključka da su mogući uticaji buke od vetroturbine značajno ispod zakonski definisanih nivoa.