Influence of FB Conditions on Processes Within a Large Fuel Particle During Initial Phases of Conversion

A theoretical study has been performed in order to investigate the interaction between fluidized bed (FB) temperature and original size of coal, and the pressure rise within a large coal particle during the initial phases of the combustion process. A mathematical model, describing the devolatilization process, has included the internal and external heat transfer, primary decomposition reactions and mass transfer. The model has shown how the FB temperature and original size of coal reflect on the pressure profile of the coal particle during the devolatilization. One of the major consequences of coal devolatilization in the fluidized bed is the primary fragmentation; hence, the special attention has been paid to this process. On the basis of the devolatilization model results, a physical model of the primary fragmentation in FB is proposed

Denitrification measures in biomass combustion

Usklađivanje potreba očuvanja životne sredine i rastućih energetskih potreba savremenog društva promoviše primenu biomase kao zamene za fosilna goriva i održivu opciju za ublažavanje emisije gasova staklene bašte. Poredniza prednosti upotrebe biomase u energetske svrhe, postoje i izvesni nedostaci, od kojih je i moguća relativno visoka emisija azotnih oksida, NOx prilikom sagorevanje ove vrste goriva. U radu su predstavljene mere denitrifikacije pri sagorevanju biomase - primarne i sekundarne. Akcenat u radu je stavljen na sekundarne mere denitrifikacije.Aligning the need to preserve the environment and the growing energy needs of modern society promotes the use of biomass as a replacement for fossil fuels and viable option to mitigate greenhouse gas emissions. Besides a number of advantages of using biomass for energy purposes, there are certain disadvantages, one of which is possible relatively high emissions of nitrogen oxides, NOx, during the combustion of these fuels. The paper presents the denitrification measures during combustion of biomass - primary and secondary. The emphasis in this paper is placed on the secondary denitrification measures.29. Međunarodni kongres o procesnoj industriji - PROCESING ′16 : zbornik radova ; 2-3. jun, Beogra

Application of analytical and CFD models of liquid fuels combustion in a fluidized bed

In Laboratory for Thermal Engineering and Energy of Institute Vinca, University of Belgrade, a 2-D CFD modeling procedure of numerical simulation of unconventional liquid fuel combustion in bubbling fluidized bed has been developed. This procedure is based on a two-fluid Euler-Euler approach modeling a fluidized bed with the determination of the velocities field of gas and particulates in two-phase, granular flows, analog to the kinetic theory of gases. This model describes in detail the unsteady motion of gas and solid phases, the formation and movement of bubbles with the combustion process in the fluidized bed, but temperature profiles calculated by the bed height differ to some extent from the experimentally obtained profiles. This discrepancy is probably due to the inability of a two-fluid CFD model to give a realistic simulation of the liquid fuel mixing in a fluidized bed. Therefore, an analytical model has been developed, where one of the basic assumptions is that the particles are mixed in the vertical direction of fluidized bed mainly by the bubble wakes. The proposed zonal type of calculating procedure is based on Davidson and Harrison two-phase model of the bubbling fluidized bed, where fluidized bed is divided into zones within which material and energy balances are set

Technical and economic feasibilityof replacing the existing heavy fuel boilers with new biomass boiler within the heating system of the institute Vinča

Institut „Vinča“ se greje iz centralne kotlarnice toplom vodom u primarnom krugu. U kotlarnici su instalisana četiri mazutna vrelovodna blok kotla ukupne snage od 9,65 MW. To je veoma zastareo sistem grejanja koji ima niz nedostataka. Međutim, promena tog sistema i eventualno prelazak na dvostepeni (primarni i sekundarni vrelovodni/toplovodni krugovi sa ugradnjom podstanica) je veoma skup poduhvat i u ovom trenutku se ne razmatra. U radu je sagledana mogućnost supstitucije postojećeg goriva (mazut) biomasom. Za tu svrhu bi se morao izgraditi novi kotao koji će sagorevati biomasu. Analiza sprovedena u ovom radu je pokazala da li je i u kojoj meri to isplativo, ekološki prihvatlјivo, energetski efikasnije, kao i koliko je naučno istraživački korisno. U radu je prikazana i analiza angažovane snage kotlarnice za dve izabrane grejne sezone, što može pomoći u određivanju potrebne instalisane snage novog kotla na biomasu. Takođe, u radu je prikazana i kompletna logistika neophodna za realizaciju korišćenja biomase kao goriva u sistemu centralnog grejanja instituta Vinča."Vinca" Institute is heated from a central boiler station using a hot water in the primary circuit. In the boiler room a four heavy fuel oil hot water block boilers were installed with total capacity of 9.65 MW. It is very outdated heating system which has a number of disadvantages. However, the change of the system and eventually change to a two-stage (primary and secondary hot water/hot water circuits with installation of substations) is a very expensive proposition and at this time is not considered. In the paper is investigated the possibilities of substitution of the existing fuel (heavy fuel oil) with biomass. For this purposes a new boiler which will burn biomass would be built.The analysis conducted in this paper has shown whether and to what extent is cost-effective, environmentally friendly, energy efficient, and how is useful from scientific and research point of view. In the paper has been presented the analysis for two selected heating season, which may help in determining the installed capacity of the new biomass boiler. Also, in the paper are presented a complete logistics system required for implementation of biomass usage as a fuel in heating system of the Vinca Institute.28. Međunarodni kongres o procesnoj industriji - PROCESING ′15 : zbornik radova ; 4-5. jun, Inđij

Kotao za sagorevanje velikih bala sojine slame za grejanje plastenika

In one of the largest agricultural companies in Serbia with over 2000 ha of soya plantations there is 4000 t/year of baled soya straw production. Soya straw biomass is planned to be used as renewable energy source for heating the greenhouses, with 5 ha in area. Therefore, efforts have been made to develop a technology for utilizing large bales of soya straw for energy production. In the first phase, a demo energy production facility - furnace was developed and built. The facility was tested in order to examine the quality of combustion of large soya straw bales. Since the experimental results obtained by testing of this facility proved to be very satisfactory in the second phase of development, the hot water boiler of similar characteristics (burning soya straw bales, with dimensions 0.7 x 1.2 x 2.7 m) was designed.U jednoj od najvećih kompanija koje se bave poljoprivrednom proizvodnjom u Srbiji pod zasadom soje se nalazi preko 2000 ha, i svake godine se proizvede oko 4000 t balirane sojine slame. Planirano je da se sojina slama koristi za grejanje plastenika, ukupne površine 5 ha. Zbog toga, u Laboratoriji za termotehniku i energetiku Instituta za nuklearne nauke 'Vinča' je učinjen napor da se razvije tehnologija za korišćenje krupne balirane biomase za proizvodnju energije. U prvoj fazi, razvijeno je demonstraciono eksperimentalno postrojenje - ložište za sagorevanje bala sojine slame. Ložište je izgrađeno i termotehnički ispitano, da bi se utvrdio kvalitet sagorevanja. Kako su rezultati ispitivanja bili veoma zadovoljavajući, u drugoj fazi razvoja, vrelovodni kotao sličnih karakteristika (koji sagoreva bale sojine slame dimenzija 0,7 x 1,2 x 2,7 m) je projektovan, i trenutno je u fazi izgradnje

Experimental apparatus for simulation of biomass combustion and control of nitrogen oxide

Iako se sagorevanje biomase promoviše sa stanovišta očuvanja životne sredine zbog značajno manje emisije štetnih gasova nego pri sagorevanju najzastupljenijeg domaćeg fosilnog goriva-uglja, eksperimenti sagorevanja više tipova biomase su pokazali da se i ovim sagorevanjem emituje izvesna količina polutanata koju je potrebno kontrolisati. Emisija azotnih oksida (NOx) je jedan od najvećih izazova u tom pogledu. Poznavanje i kontrolisanje emisije ovih oksida prilikom sagorevanja biomase je neophodno radi uspostavljanja korektnih zakonskih normi u pogledu granične emisije i za razvoj što kvalitetnijih tehnologija za sagorevanje ove vrste goriva. U tom cilju u radu je dat opis eksperimentalne aparature, koja ima za cilj da ispita efikasan način za redukciju NOx-a u dimnim gasovima upotrebom sekundarnih mera denitrifikacije. Takođe su dati i termički proračuni parametara sagorevanja u eksperimentalnom adijabatskom ložištu.Even though biomass combustion is promoted from the standpoint of environmental protection due to significantly lower emissions in comparison to combustion of the predominate domestic fossil fuel –coal, combustion experiments with several types of biomass showed that the combustion emits a certain amount of pollutants which needs to be controlled. Emissions of nitrogen oxides (NOx) is one of the biggest challenges in this regard. Knowing and controlling the emissions of these oxides during the combustion ofbiomass is required for correct establishment of legal norms in terms of the emis-sions limits and to develop better technologies for combustion of these fuels. In that sense, the paper gives a description of the new experimental apparatus, which aims to explore an effective way to re-duce NOx in the exhaust gas, using the secondary denitrification methods. The calculation of the main combustion parameters in the experimental adiabatic furnace are also given here30. Međunarodni kongres o procesnoj industriji - PROCESING ′17 : zbornik radova ; 1-2. jun, Beogra

Аpproximate method for the estimation of energy performance of heat pumps connected to the system of energy management of facilities

Due to their efficiency heat pumps have found great application in the building industry, the process industry, in various technological processes in the production of food, to the space technology system, etc. When heat pumps are coupled to the energy management system which monitors and optimizes work parameters not only of the heat pump but also work parameters of other systems, such as solar and photovoltaic panels, thermal energy storages, electric batteries and the whole system, it is necessary to have a mathematical model that with sufficient accuracy and without great complexity estimates energy performance of the heat pump itself and the whole energy system. In this article a relatively simple mathematical model of a heat pump, with which it is possible to get values for the COP at any given time and under given conditions, was given. The obtained results of the model, applied to the air-water heat pump, used the input meteorological data of the mean air temperature for Belgrade, were presented. The verification of the obtained results of the model was made by using the catalogue data for the COP of the the Ecodan Monobloc Air Source Heat Pumps manufactured by Mitsubishi Electric

Boiler combusting large soya straw bales for heating the greenhouses complex

U jednoj od najvećih kompanija koje se bave poljoprivrednom proizvodnjom u Srbiji pod zasadom soje se nalazi preko 2000 ha, i svake godine se proizvede oko 4000 t balirane sojine slame. Planirano je da se sojina slama koristi za grejanje plastenika, ukupne površine 5 ha. Zbog toga, u Laboratoriji za termotehniku i energetiku Instituta za nuklearne nauke 'Vinča' je učinjen napor da se razvije tehnologija za korišćenje krupne balirane biomase za proizvodnju energije. U prvoj fazi, razvijeno je demonstraciono eksperimentalno postrojenje - ložište za sagorevanje bala sojine slame. Ložište je izgrađeno i termotehnički ispitano, da bi se utvrdio kvalitet sagorevanja. Kako su rezultati ispitivanja bili veoma zadovoljavajući, u drugoj fazi razvoja, vrelovodni kotao sličnih karakteristika (koji sagoreva bale sojine slame dimenzija 0,7 x 1,2 x 2,7 m) je projektovan, i trenutno je u fazi izgradnje.In one of the largest agricultural companies in Serbia with over 2000 ha of soya plantations there is 4000 t/year of baled soya straw production. Soya straw biomass is planned to be used as renewable energy source for heating the greenhouses, with 5 ha in area. Therefore, efforts have been made to develop a technology for utilizing large bales of soya straw for energy production. In the first phase, a demo energy production facility - furnace was developed and built. The facility was tested in order to examine the quality of combustion of large soya straw bales. Since the experimental results obtained by testing of this facility proved to be very satisfactory in the second phase of development, the hot water boiler of similar characteristics (burning soya straw bales, with dimensions 0.7 x 1.2 x 2.7 m) was designed

Boiler combusting large soya straw bales for heating the greenhouses complex

U jednoj od najvećih kompanija koje se bave poljoprivrednom proizvodnjom u Srbiji pod zasadom soje se nalazi preko 2000 ha, i svake godine se proizvede oko 4000 t balirane sojine slame. Planirano je da se sojina slama koristi za grejanje plastenika, ukupne površine 5 ha. Zbog toga, u Laboratoriji za termotehniku i energetiku Instituta za nuklearne nauke 'Vinča' je učinjen napor da se razvije tehnologija za korišćenje krupne balirane biomase za proizvodnju energije. U prvoj fazi, razvijeno je demonstraciono eksperimentalno postrojenje - ložište za sagorevanje bala sojine slame. Ložište je izgrađeno i termotehnički ispitano, da bi se utvrdio kvalitet sagorevanja. Kako su rezultati ispitivanja bili veoma zadovoljavajući, u drugoj fazi razvoja, vrelovodni kotao sličnih karakteristika (koji sagoreva bale sojine slame dimenzija 0,7 x 1,2 x 2,7 m) je projektovan, i trenutno je u fazi izgradnje.In one of the largest agricultural companies in Serbia with over 2000 ha of soya plantations there is 4000 t/year of baled soya straw production. Soya straw biomass is planned to be used as renewable energy source for heating the greenhouses, with 5 ha in area. Therefore, efforts have been made to develop a technology for utilizing large bales of soya straw for energy production. In the first phase, a demo energy production facility - furnace was developed and built. The facility was tested in order to examine the quality of combustion of large soya straw bales. Since the experimental results obtained by testing of this facility proved to be very satisfactory in the second phase of development, the hot water boiler of similar characteristics (burning soya straw bales, with dimensions 0.7 x 1.2 x 2.7 m) was designed

Аpproximate method for the estimation of energy performance of heat pumps connected to the system of energy management of facilities

Due to their efficiency heat pumps have found great application in the building industry, the process industry, in various technological processes in the production of food, to the space technology system, etc. When heat pumps are coupled to the energy management system which monitors and optimizes work parameters not only of the heat pump but also work parameters of other systems, such as solar and photovoltaic panels, thermal energy storages, electric batteries and the whole system, it is necessary to have a mathematical model that with sufficient accuracy and without great complexity estimates energy performance of the heat pump itself and the whole energy system. In this article a relatively simple mathematical model of a heat pump, with which it is possible to get values for the COP at any given time and under given conditions, was given. The obtained results of the model, applied to the air-water heat pump, used the input meteorological data of the mean air temperature for Belgrade, were presented. The verification of the obtained results of the model was made by using the catalogue data for the COP of the the Ecodan Monobloc Air Source Heat Pumps manufactured by Mitsubishi Electric