1. Integrated optimization framework for a biomass supply network and steam Rankine cycleMonika Dokl, Zdravko Kravanja, Lidija Čuček, 2024, izvirni znanstveni članek Opis: The optimization of biomass supply chains is becoming increasingly important, especially for low-density biomass feedstocks that have limited market value and require efficient handling and logistics. This study addresses this issue by proposing an integrated approach to optimize biomass supply chain networks for energy production with the steam Rankine cycle. The approach takes into account the inherent variability of feedstock availability and energy market values, to ensure adaptability to fluctuating conditions. The biomass supply network is formulated as a mixed-integer nonlinear programming problem, where the optimization objective is to maximize the economic viability of the system. The optimal configuration of the supply network includes the selection of biomass supply zones and storage facilities, the transportation links, and the optimization of the process variables within the conversion plants, taking into account the variable heat demand. The optimization approach is applied to a hypothetical case study of a relatively small region in Slovenia. The results show the economic viability of biomass utilization with a net present value of almost 300 MEUR, generating about 4 MW of electricity and 65 MW of heat. The uncertainties of the biomass supply, the fluctuations in product prices and the spatial scope of the case study are evaluated in addition. This analysis highlights and discusses the impact of these factors on the economic performance of the biomass supply chain network.
Ključne besede: copper(II) coordination compounds, methylamines, crystal structure, magnetic properties, thermogravimetric analysis
Objavljeno v DKUM: 31.01.2025; Ogledov: 0; Prenosov: 3
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2. 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: 22
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3. Thermo-kinetic analysis of pyrolysis of thermally pre-treated sewage sludge from the food industryAleksandra Petrovič, Janja Stergar, Lidija Škodič, Neža Rašl, Tjaša Cenčič, Lidija Čuček, Darko Goričanec, Danijela Urbancl, 2023, izvirni znanstveni članek Ključne besede: thermal pre-treatment, pyrolysis, industrial sewage sludge, thermogravimetric analysis, kinetic analysis, thermodynamic analysis
Objavljeno v DKUM: 10.05.2024; Ogledov: 258; Prenosov: 13
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4. Subsolidus phase equilibria and the Li[sub]5Nd[sub]4FeO[sub]10 phase in the Li[sub]2O-Nd[sub]2O[sub]3-Fe[sub]2O[sub]3 systemIrena Ban, Mihael Drofenik, Danilo Suvorov, Darko Makovec, 2005, izvirni znanstveni članek Opis: A survey of the subsolidus phase equilibria in the system Li2O-Nd2O3-Fe2O3 wasmade at subsolidus temperatures in the range 1000-1050 °C. A ternary phase was identified. The phase is centered on Li5Nd4FeO10, with a cubic lattice a =11.9494 A. The compound melts incongruently at 1105 °C. The magnetic susceptibility was measured in the temperature range 4-300 K. The compound is paramagnetic in the temperature range 150-300 K and follows the Curie-Weiss law. At about TN = 10 K, a long-range magnetic ordering is observed.
Ključne besede: lithium ferrites, differential scanning calorimetry, thermogravimetric analysis, X-ray diffraction, magnetic properties, phase equilibrium
Objavljeno v DKUM: 01.06.2012; Ogledov: 2598; Prenosov: 38
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