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1.
The Thermochemical Conversion of Municipal Solid Waste by Torrefaction Process
Maja Ivanovski, Darko Goričanec, Danijela Urbancl, 2023, izvirni znanstveni članek

Opis: In this work, the thermochemical properties of municipal solid waste (MSW) are studied using the torrefaction process as the main method for investigation. Torrefaction experiments were carried out using an electric laboratory furnace, at temperatures of 200, 250, and 300 °C. The residence time was set to 90 min. Proximate and ultimate analysis were performed on the torrefied MSW samples and compared with the properties of the raw MSW samples. In addition, the thermal properties of the obtained torrefied MSW samples were evaluated by thermogravimetric analysis (TGA) and derivative thermogravimetric analysis (DTG). The following could be stated: the obtained results showed that mass and energy yields (MY and EY, respectively) decrease with increasing when torrefaction temperature, while the heating values (HHV) increased under the same conditions (from 24.3 to 25.1 MJ/kg). Elemental analysis showed an increase in carbon content (C), from 45.7 ± 0.9 to 52.8 ± 1.05 wt.%, and decrease in oxygen content (O), from 45.6 ± 0.9 to 39.5 ± 0.8 wt.%, when torrefaction temperature is increased, which is consistent with the general definition of the torrefaction process. In addition, enhancement factors (EFs) and fuel ratios (FRs) were calculated, which ranged from 1.00 to 1.02 and 0.16 to 0.23, respectively. Some anomalies were observed during the thermal analysis, which are assumed to be related to the composition of the selected MSW. This study therefore shows that torrefaction pretreatment can improve the physicochemical properties of raw MSW to a level comparable to coal, and could contribute to a better understanding of the conversion of MSW into a valuable, solid biofuel.
Ključne besede: biomass, municipal solid waste, torrefication, energy yield, thermogravimetric analysis
Objavljeno v DKUM: 10.05.2024; Ogledov: 100; Prenosov: 5
.pdf Celotno besedilo (1,63 MB)
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2.
Particulate matter air pollution in the Republic of Slovenia and its national spatial emissions release
Petra Dolšak Lavrič, Maja Ivanovski, Darko Goričanec, Danijela Urbancl, 2023, izvirni znanstveni članek

Opis: In this work, an impact of particulate matter (PM) on air pollution and its emissions released is investigated. Concentration levels of PM10 and PM2.5 in the Republic of Slovenia (RS) were analyzed on daily, weekly, monthly, quartile, and annual data and then compared. The study was conducted from January 1, 2020 to December 31, 2020 at two monitoring stations, so-called urban traffic and urban industrial. Obtained results showed that the highest concentrations of PM in air were during the cold months of the year when the temperatures are lower (< 6%). Results from heating seasons (from October 1, 2019 and March 31, 2020 and from October 1, 2020 to March 31, 2021) showed the highest concentration levels of PM10 between 9:00 and 14:00 and between 18:00 and 22:00, with highest concentrations recorded during the winter months (January and February). Additionally, emission building inventory was built based on PM10 and PM2.5 emissions released. The study includes yearly spatial building emissions release model considering currently installed high PM emitted stoves. The building model for the Republic of Slovenia has been developed by using 500 x 500 m model grid. Obtained results showed that changing currently low efficient appliance with advanced appliance would result in significant lower PM emissions released from building sector
Ključne besede: air pollution, particulate matter, heating season, emission release, Slovenia
Objavljeno v DKUM: 10.05.2024; Ogledov: 115; Prenosov: 4
.pdf Celotno besedilo (1,12 MB)
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3.
Proizvodnja biogoriv s procesom torefikacije in njihov vpliv na okolje : doktorska disertacija
Maja Ivanovski, 2024, doktorska disertacija

Opis: Skozi zgodovino se je ves svet ukvarjal s pridobivanjem energije in njeno oskrbo ter posledično razvojem goriv. Zaradi postopnega izčrpavanja zalog fosilnih goriv, tehnološkega napredka in vse večjih okoljskih vprašanj so začela prihajati v ospredje alternativna goriva, ki jih je mogoče črpati na bolj učinkovit in trajnosten način. Energija iz biomase danes predstavlja enega bolj obetavnih obnovljivih virov energije (OVE) v Sloveniji, eni najmanjših držav v Evropi. Med obstoječimi tehnologijami za izboljšanje kakovosti biomase predstavlja proces torefikacije odpadne biomase ambiciozno tehniko predhodne obdelave biomateriala, ki lahko bistveno izboljša lastnosti surove biomase tako, da dobimo ekološko in energetsko sprejemljivejši energent. Toreficirana oz. termično obdelana biomasa je hidrofobna, odporna na biorazgradnjo in primerna za skladiščenje. Pomembna prednost toreficirane biomase je tudi v tem, da ima manjšo žilavost od lesa, kar omogoča lažje mletje in aplikacijo tega biomateriala v industrijske namene. Čeprav so prednosti uporabe toreficirane biomase na svetovni ravni že raziskane in priznane, torefikacija v Sloveniji še ni poznana. V nadaljevanju doktorska disertacija obravnava proces torefikacije odpadne biomase tipične v Sloveniji z namenom proizvesti trdno biogorivo, ki ima višjo kurilno vrednost kot surova biomasa in je tudi hidrofobno: energetska rastlina miskantus (M), ostanek hmelja po žetvi (H), odpadni mešani (MWW) in hrastov les (OWW), odpadno blato iz komunalnih čistilnih naprav (SS), mešane komunalne odpadke (MSW) in njihove mešanice. Torefikacija odpadne lignocelulozne in ne-lignocelulozne biomase je potekala v temperaturnem območju med 200 °C in 300 °C, v inertni ali pol-inertni atmosferi, od nekaj minut do nekaj ur. Na surovih in termično obdelanih biomaterialih so bile izvedene standardne fizikalno-kemijske analize, s katerimi je bila raziskovana odpadna biomasa kvantitativno in kvalitativno ovrednotena (proksimativna in elementna analiza, masni in energijski izplen, faktor izboljšav kurilne vrednosti, indeks stopnje torefikacije itd.). Z infrardečo spektroskopijo s Fourierjevo transformacijo (FTIR) je bila določena struktura vzorcev, s termogravimetrično analizo (TGA in DTG) pa je bila določena termična razgradnja surovih in obdelanih biomaterialov. Pridobljeni podatki so bili analizirani z dvema kinetičnima modeloma: Friedman (FR) in Kissinger-Akahira-Sunose (KAS). Na koncu je bila še izračunana energetska donosnost procesa torefikacije, določene so bile emisije toplogrednih plinov (TGP) in določeni so bili plini, ki se sprostijo med procesom. Ugotovljeno je bilo naslednje: z naraščajočo temperaturo in/ali daljšanjem procesa torefikacije se masni in energetski izpleni vseh raziskovanih vzorcev nižajo, kurilne vrednosti (HHV) se višajo. Delež kisika v vzorcih se zmanjša, prav tako se zniža delež hlapljivih komponent, medtem ko se deleži ogljika in fiksnega ogljika zvišajo. Prav tako se delež lignina v lignoceluloznih vzorcih viša z višanjem temperature, deleža celuloze in hemiceluloze pa se nižata. Temperatura torefikacije ima večji vpliv na proces kot čas torefikacije, pri čemer je optimalna temperatura procesa pri približno 260 °C. To je bilo potrjeno tudi z indeksom stopnje (TSI) torefikacije in EMCI indeksom. Nadalje je FTIR analiza pokazala, da imajo tako surovi kot termično obdelani vzorci funkcionalne skupine tipične za lignocelulozne in ne-lignocelulozne vzorce. Termogravimetrična analiza je pokazala, da se večina obravnavanih vzorcev razgradi v temperaturnem območju do 550 °C. Med samo torefikacijo pa se je sprostilo največ CO2 plina. Obravnavi vzorci odpadne biomase se na podlagi dobljenih rezultatov lahko uporabijo kot možno alternativno biogorivo. Več raziskav in analiz na tem področju je še potrebnih.
Ključne besede: obnovljivi viri energije, torefikacija, odpadna biomasa, kurilna vrednost, emisije TGP
Objavljeno v DKUM: 06.05.2024; Ogledov: 73; Prenosov: 15
.pdf Celotno besedilo (35,92 MB)

4.
The Evaluation of Torrefaction Efficiency for Lignocellulosic Materials Combined with Mixed Solid Wastes
Maja Ivanovski, Darko Goričanec, Danijela Urbancl, 2023, izvirni znanstveni članek

Opis: The paper presents the results of research aimed at evaluating the possibility of using selected biomass wastes to produce solid biofuels. In this work, the thermochemical properties of two lignocellulosic biomasses, namely, miscantshus (Miscanthus × Giganteus) and hops (Humulus lupulus), and non-lignocellulosic biomass, namely, municipal solid waste, and their mixtures (micanthus + municipal solid waste and hops + municipal solid waste) were studied using the torrefaction process as the main method for investigation. The effects of various torrefaction temperatures (250, 300, and 350 °C) and times (30 and 60 min) were evaluated. Proximate and ultimate analyses were performed on the torrefied samples. The following can be stated: as the torrefaction temperature and time increased, mass and energy yields decreased while the higher heating values (HHVs) and fuel ratios (FRs) increased, together with carbon contents (C). In addition, energy on return investment (EROI) was studied; the maximum EROI of 28 was achieved for MSW biochar at 250 °C for 30 min. The results of studying greenhouse gas emissions (GHGs) showed a reduction of around 88% when using torrefied biochar as a substitute for coal. In sum, this study shows that torrefaction pre-treatment can improve the physicochemical properties of raw biomasses to a level comparable with coal, and could be helpful in better understanding the conversion of those biomasses into a valuable, solid biofuel.
Ključne besede: torrefaction, waste biomass, renewable energy, fuel ratio, greenhouse gas emission, GHG
Objavljeno v DKUM: 29.03.2024; Ogledov: 109; Prenosov: 11
.pdf Celotno besedilo (3,69 MB)
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5.
Assessment of Air Pollution in Different Areas (Urban, Suburban, and Rural) in Slovenia from 2017 to 2021
Maja Ivanovski, Kris Alatič, Danijela Urbancl, Marjana Simonič, Darko Goričanec, Rudi Vončina, 2023, izvirni znanstveni članek

Opis: Air pollution can have a significant effect on human health. The present work is focused on the investigation of daily, monthly, and annual concentration levels of five typical air pollutants (SO2, NO2, NOX, PM10, and PM2.5) in the Republic of Slovenia (RS) from January 2017 to December 2021. The study was conducted at five different monitoring stations of the following kind: traffic (A), industrial (D), and background (B, C, E). The obtained results showed a decline in the average concentrations for all the studied air pollutants through the years, respectively. The daily average SO2 concentrations were the lowest in the year 2021 at location B, which is classified as background location, while the highest were detected in the year 2018 at location E, which is also classified as background location. The average daily concentrations of NO2 and NOX were the highest at location A in the year 2017, whereas the lowest were detected in the year 2010 and 2021. It is believed that those results are a consequence of measures set by the Slovenian government during the COVID-19 pandemic. The PM10 and PM2.5 daily average concentrations were the highest at location A in 2017, while the lowest were observed in the year 2019 at location C. Meteorological parameters (temperature, wind speed, and relative humidity) were studied in addition. In general, the high temperatures in ambient air are responsible for the intense concentrations of air pollutants. It was found in the study results for temperature, wind speed, and relative humidity that no significant difference was shown between studied years.
Ključne besede: air pollution, air quality, air pollutants, meteorology, Republic of Slovenia
Objavljeno v DKUM: 28.03.2024; Ogledov: 117; Prenosov: 16
.pdf Celotno besedilo (3,30 MB)
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6.
Exploring the properties of the torrefaction process and its prospective in treating lignocellulosic material
Maja Ivanovski, Aleksandra Petrovič, Darko Goričanec, Danijela Urbancl, Marjana Simonič, 2023, pregledni znanstveni članek

Opis: The main objective of this review is to present the latest research results regarding the importance of the torrefaction process for different biomass materials in the last 12-year period. Despite the fact that the potential of renewable energy sources has been analyzed, research regarding that of energy derived from waste biomass still remains in the infancy state. Torrefaction is known to be one of the most effective methods for enhancing the energy efficiency of biomass. Among different types of torrefactions, the focus in this study is mostly on dry torrefaction. The influential factors, like temperature and residence time, and physico-chemical properties of torrefied products, and the prospective of torrefaction due to its reduced impact on environment, are discussed in-depth. This review provides valuable insights into the torrefaction process, which is conducive to upgrading biomass for achieving net zero carbon emissions, as it has been stated in several works that torrefied biomass can be used instead of coal.
Ključne besede: torrefaction, lignocellulosic biomass, waste biomass, biomass properties
Objavljeno v DKUM: 22.03.2024; Ogledov: 352; Prenosov: 693
.pdf Celotno besedilo (1,74 MB)
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7.
Analiza onesnaženosti zraka na območju Slovenije : diplomsko delo visokošolskega strokovnega študijskega programa I. stopnje
Tim Tetičkovič, 2022, diplomsko delo

Opis: Kakovost zraka pomembno vpliva na kvaliteto našega življenja, kar se dosega z nadziranjem prisotnih onesnažil v ozračju. Ustreznost kvalitete zraka nadzoruje Javna agencija Republike Slovenije za okolje (ARSO), ki vsakodnevno objavlja podatke o vsebnosti onesnažil v ozračju. Cilj diplomske naloge je bil na podlagi javno dostopnih podatkov opraviti analizo onesnaženosti zraka pri nas. Izbrali smo področja, ki se razlikujejo po reliefu, vremenskih razmerah in poseljenosti, saj smo želeli ugotoviti, kakšni so vzroki za prisotnost različnih onesnažil v ozračju. V delu smo analizirali naslednja onesnažila: SO2, NO2/NOx in prašne delce PM10 ter PM2,5 na posameznih merilnih mestih v obdobju od 2010 do 2020. V diplomski nalogi smo ugotovili, da sta meteorologija in reliefna razgibanost tesno povezani s koncentracijo onesnažil v ozračju. Z analizo vpliva temperature in relativne vlažnosti na kakovost zraka smo ugotovili, da visoka temperatura in nizka relativna vlažnost prispevata k čistejšemu ozračju. Prav tako se onesnaženost spreminja tekom leta in se v zimskem letnem času poveča, v poletnem pa zniža. Temeljni problem onesnaženosti zraka predstavljajo delci PM10, ki postavljajo človeško zdravje v nevarnost. Na prometnih vpadnicah glavni vir onesnaženosti predstavljajo NO2/NOx, v okolici termoelektrarn, industrijskih obratov in malih kurišč pa SO2.
Ključne besede: zrak, onesnaženost, kvaliteta, PM10, PM2, 5, Slovenija
Objavljeno v DKUM: 19.07.2022; Ogledov: 729; Prenosov: 98
.pdf Celotno besedilo (2,60 MB)

8.
Functionalized copolymers from macrolactones by enzymatic ring-opening polymerization
Maja Ivanovski, 2018, magistrsko delo

Opis: The work reported in the present thesis is focused predominantly to investigate how to synthesize random copolymers from ω-pentadecalatone (ω-PDL) and globalide (Gl) by enzymatic ring-opening polymerization (eROP). The reason for choosing this specific theme, i.e. "Functionalized copolymers from macrolactones by enzymatic ring-opening polymerization", was to explore a relatively new concept, in which two cyclic esters (macrolactones) – ω-PDL and Gl were synthesized by a combination of eROP and thiol-ene click reaction using biocatalyst Novozym 435 (lipase B from Candida antarctica). The aim was to position the newborn copolymer from ω-pentadecalactone and globalide among other biomaterials, identify possible applications and prepare nanoparticles that can be used in drug delivery systems. Random copolymers PPDLx-r-PGly with different feed ratios were successfully synthesized and later modified via thiol-ene click reaction when using BAET as a suitable compound for this polymeric functionalization, due to its thiol functionality. Boc-amino deprotection lasted and at the end, graft-copolymers were obtained (PPDLx-r-(PGly-g-PBLGz). Characterization methods were performed on GPC and NMR. The yield for all obtained random copolymers ranged between 67% and 88% and Mn between 14 000 g/mol and 45 000 g/mol depending on feed ratio of random copolymers. Meanwhile, the calculated yield for obtained grafted-copolymers ranged between 63% and 95%. Mn detected by GPC was around 7 000 g/mol for both grafted-copolymers (PPDL90(PGl10-PBLGz) and PPDL50(PGl50-PBLGz)) and Mw between 14 000 g/mol and 21 000 g/mol. Thermal analyses were performed on TGA and DSC. TGA showed that obtained PPDLx-r-PGly copolymers start to decompose at around 400 °C and grafted PPDLx-r-(PGly-g-PBLGz) copolymers at around 250 °C. DSC showed that PPDL and PGl are semicrystalline polymers with Tm ranging between (95 and 96 °C) for PPDL and (41 and 42 °C) for PGl. AFM technique was used for nanoparticles characterization. The resulting surface and deep resolution of PPDL50(PGl50-PBLGz) nanoparticles was between (2 to 88.8 nm) and PPDL10(PGl90-PBLGz) between (2 nm to 94.4 nm).
Ključne besede: ring-opening polymerization, macrolactones, ω-pentadecalatone, globalide, nanoparticles, Novozym 435
Objavljeno v DKUM: 04.10.2018; Ogledov: 1190; Prenosov: 271
.pdf Celotno besedilo (2,16 MB)

9.
KONTROLA ELASTIČNIH LASTNOSTI BETONA Z DODATKOM GUMENIH SEKANCEV
Maja Ivanovski, 2016, diplomsko delo

Opis: Teoretični del diplomske naloge prikazuje analizo komponent betona, proizvedenega z uporabo recikliranih materialov. V praktičnem delu smo prikazali izdelavo vzorcev betona, ki smo jim z dodanim elektrofiltrskim pepelom (EFP) želeli zmanjšati količino cementa. V betonsko mešanico smo vmešali dve vrsti EFP. Prva serija vzorcev je bila izdelana z EFP, ki je bil proizveden iz rjavega premoga, drugi del vzorcev pa z EFP iz lignita. Z kemijsko analizo smo ugotovili, da je v EFP iz rjavega premoga več reaktivne komponente SiO2, v EFP iz lignita pa je več reaktivne komponente CaO. Prav tako smo del mineralnega agregata nadomestili z gumenimi sekanci. Preiskave vzorcev otrdelega betona po končanem vezanju so potrdile hipotezo, da je beton z dodanimi sekanci iz gume elastičen material. Meritve so pokazale, da ima beton z dodatkom gumenih sekancev in EFP iz rjavega premoga višji modul elastičnosti kot beton, ki smo mu dodali EFP iz lignita.
Ključne besede: elektrofiltrski pepel, gumeni sekanci, beton, lastnosti, modul elastičnosti
Objavljeno v DKUM: 16.09.2016; Ogledov: 1685; Prenosov: 120
.pdf Celotno besedilo (2,17 MB)

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