1. Improving lignocellulosic and non-lignocellulosic biomass characteristics through torrefaction processMaja Ivanovski, Danijela Urbancl, Aleksandra Petrovič, Janja Stergar, Darko Goričanec, Marjana Simonič, 2022, izvirni znanstveni članek Opis: In this study, three locally available biomasses, namely miscanthus, hops, sewage sludge,
and additionally, their mixtures, were subjected to the torrefaction process to improve their fuel
properties. The torrefaction process was conducted at 250–350 ◦C and 10–60 min in a nitrogen
(N2) environment. The torrefaction temperature and time were studied to evaluate the selected
biomass materials; furthermore, heating values, mass and energy yields, enhancement factors,
torrefaction severity indexes (TSI), and energy-mass co-benefit indexes (EMCI) were calculated. In
addition, thermogravimetric (TGA) and Fourier transform infrared analyses (FTIR) were performed
to characterize raw and torrefied biomass under the most stringent conditions (350 ◦C and 60 min).
The results showed that with increasing torrefaction temperature and duration, mass and energy
yields decreased, and heating values (HHVs) increased for all studied biomasses. The results of the
TSI and EMCI indexes showed that the optimum torrefaction conditions were as follows: 260 ◦C
and 10 min for pure miscanthus and hops, whilst this could not be confirmed for the sewage sludge.
Furthermore, the combination of sewage sludge and the above-mentioned types of lignocellulosic
biomass exhibited better fuel properties than sewage sludge alone.
Ključne besede: lignocellulosic biomass, sewage sludge, torrefication, thermogravimetry, TSI
Objavljeno v DKUM: 10.04.2025; Ogledov: 0; Prenosov: 9
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2. Cu(II) and Ni(II) adsorption on torrefied wood waste biomassMarjana Simonič, Darko Goričanec, Aleksandra Petrovič, Ilda Silić, Danijela Urbancl, 2025, izvirni znanstveni članek Opis: The aim of the research was to study the torrefaction processes of wood biomass, compare the product characteristics at different torrefaction temperatures, and assess both moisture adsorption on raw and torrefied samples, as well as metal (Cu(II) and Ni(II)) adsorption on torrefied biomass. The novelty of the research was to investigate whether the presence of adsorbed metals in torrefied biomass significantly affects the energetic properties of the torrefied biomass, compared to torrefied biomass without metals. First, wood samples were torrefied at temperatures of 250 °C, 350 °C, and 400 °C. Following torrefaction, thermogravimetric analysis (TGA) was performed to evaluate mass loss and thermal stability. Next, changes in surface functional groups were examined, and higher heating values (HHV) were measured to assess the energy content. The results showed that torrefaction significantly increased the hydrophobicity of the biomass, leading to reduced moisture adsorption and enhanced material properties. Additionally, the adsorption of Cu(II) and Ni(II) ions on torrefied biomass was investigated. The results showed that the adsorption efficiency for Cu(II) was higher, reaching 62.4%, compared to Ni(II) at 21.2%. The adsorption process followed a pseudo-second-order kinetic model, which indicated that chemisorption was the dominant mechanism.
Ključne besede: adsorption, torrefication, nitrogen atmosphere, metals
Objavljeno v DKUM: 12.03.2025; Ogledov: 0; Prenosov: 5
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3. The Thermochemical Conversion of Municipal Solid Waste by Torrefaction ProcessMaja 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: 255; Prenosov: 24
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