1. Chemistry of the iron-chlorine thermochemical cycle for hydrogen production utilizing industrial waste heatMatjaž Valant, Uroš Luin, 2024, original scientific article Abstract: This research presents an inventive thermochemical cycle that utilizes a reaction between iron and HCl acid for hydrogen production. The reaction occurs spontaneously at room temperature, yielding hydrogen and a FeCl2 solution as a by-product. Exploring the thermal decomposition of the FeCl2 by-product revealed that, at conditions suitable for utilization of low-temperature industrial waste heat (250 °C), chlorine gas formation can be circumvented. Instead, the resulting by-product is HCl, which is readily soluble in water, facilitating direct reuse in subsequent cycles. The utilization of low-temperature industrial heat not only optimizes resource utilization and reduces operational costs but also aligns with environmentally sustainable production processes. From the kinetic studies the activation energy was calculated to be 45 kJ/mol and kinetics curves were constructed. They showed significant kinetics at room temperature and above but rapid decrease towards lower temperatures. This is important to consider during real-scale technology optimization. The theoretical overall energy efficiency of the cycle, with 100% and 70% heat recuperation, was calculated at 68.8% and 44.8%, respectively. In practical implementation, considering the efficiency of DRI iron reduction technology and free waste heat utilization, the cycle achieved a 41.7% efficiency. Beyond its energy storage capabilities, the Iron-chlorine cycle addresses safety concerns associated with large-scale hydrogen storage, eliminating self-discharge, reducing land usage, and employing cost-effective storage materials. This technology not only facilitates seasonal energy storage but also establishes solid-state energy reserves, making it suitable for balancing grid demands during winter months using excess renewable energy accumulated in the summer.
Keywords: chemical cycles, hydrogen production, thermal decomposition, reaction kinetics, iron, chlorine
Published in RUNG: 12.01.2024; Views: 494; Downloads: 5
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5. Eco-conscious nanofluids : exploring heat transfer performance with graphitic carbon nitride nanoparticlesVijayakumar Gokul, Mohanachandran Nair Sindhu Swapna, Sankaranarayana Iyer Sankararaman, 2023, original scientific article Abstract: Abstract
The work explores the heat transfer capabilities of semiconducting graphitic carbon nitride (g-C3N4) nanofluids. Also, it presents a sustainable and eco-friendly method for synthesizing g-C3N4 nanoparticles using commercially available rice flour as a natural carbon precursor through hydrothermal treatment. The synthesized sample subjected to various characterizations, including analysis of their structure, morphology, thermal properties, and optical properties. The optical bandgap (2.66 eV) is deduced through Tauc plot analysis and reveals the semiconducting nature of the sample. The formation of g-C3N4 is confirmed by various spectroscopic techniques, including X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR), and Raman spectroscopy. Thermogravimetric analysis (TGA) demonstrates the nanoparticles’ excellent thermal stability up to 550 °C, indicating potential applications in heat transfer fluids. The investigation of concentration-dependent thermal diffusivity variation using the sensitive mode mismatched dual beam thermal lens technique highlights the potential of g-C3N4 semiconductor nanofluid as an organic and metal-free additive in industry-demanding coolant applications.
Keywords: thermal lens, nanofluids
Published in RUNG: 05.01.2024; Views: 512; Downloads: 4
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7. Silica-coated ▫$Bi2_Se_3$▫ topological insulator nanoparticles: preserving their optical properties and make them biocompatible : preserving their optical properties and make them biocompatibleBlaž Belec, Nina Kostevšek, Giulia Della Pelle, Sebastjan Nemec, Slavko Kralj, Martina Bergant Marušič, Sandra Gardonio, Mattia Fanetti, Matjaž Valant, 2023, published scientific conference contribution abstract Keywords: topological insulator, bismuth selenide, photo-thermal material, biocompatibility, nanoparticles
Published in RUNG: 19.10.2023; Views: 743; Downloads: 3
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8. A dual-wavelength photothermal aerosol absorption monitor : design, calibration, performance and measurements of coated sootGriša Močnik, 2023, invited lecture at foreign university Keywords: aerosol absorption, photo-thermal interferometer, absorption coefficient, black carbon, soot, aerosol coating, absorption enhancement
Published in RUNG: 05.10.2023; Views: 889; Downloads: 1
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