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- Aragon-Briceno, Christian, et al.
(author)
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Integration of hydrothermal carbonization treatment for water and energy recovery from organic fraction of municipal solid waste digestate
- 2022
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In: Renewable energy. - : Elsevier BV. - 0960-1481 .- 1879-0682. ; 184, s. 577-591
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Journal article (peer-reviewed)abstract
- Anaerobic digestion is an efficient way of using a wet fraction of municipal solid waste (MSW) for energy purposes as it can produce biogas. The moisture content of the digestate after application of mechanical dewatering is still high, and the amount of heat needed for drying is significant. Hydrothermal carbonization (HTC) is a process that can potentially offer great benefits by improved mechanical dewatering and valorization of the digestate into a better quality solid fuel. This study focuses on the determination of the optimum HTC process conditions to recover water from the MSW digestate. Different process conditions as temperature (180, 200, and 230 °C) and residence time (30, 60, and 120 min) were tested. Furthermore, a mass and energy balance was carried out and a process model in Aspen Plus was built. Results showed that HTC treatment increased the water recovery (40–48%) during the dewatering process compared with the original feedstock (18%). The process model showed a positive energy balance of 110 kWh per ton of MSW digestate treated with an electrical efficiency of 23.9%.
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| 2. |
- Pawlak, Michał, et al.
(author)
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Investigating the long secondary period phenomenon with the ASAS-SN and Gaia data
- 2024
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In: Astronomy and Astrophysics. - 0004-6361. ; 682
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Journal article (peer-reviewed)abstract
- Aims. The aim of this work is to create a complete list of sources exhibiting a long secondary period (LSP) in the ASAS-SN catalog of variable stars, and analyze the properties of this sample compared to other long period variables without an LSP. Methods. We used the period-amplitude diagram to identify the 55 572 stars showing an LSP, corresponding to 27% of the pulsating red giants in the catalog. We used astrometric data from Gaia DR3 and spectroscopic data provided by the APOGEE, GALAH, and RAVE surveys to investigate the statistical properties of the sample. Results. We find that stars displaying an LSP have a spatial distribution that is more dispersed than that of the non-LSP giants, suggesting that they belong to an older population. Spectroscopically derived ages seem to confirm this. The stars with an LSP also appear to be different in terms of the C/O ratio from their non-LSP counterparts.
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| 3. |
- Wang, Shule, 1994-, et al.
(author)
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Effect of hydrothermal carbonization pretreatment on the pyrolysis behavior of the digestate of agricultural waste : A view on kinetics and thermodynamics
- 2022
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In: Chemical Engineering Journal. - : Elsevier BV. - 1385-8947 .- 1873-3212. ; 431, s. 133881-
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Journal article (peer-reviewed)abstract
- Anaerobic digestion is the most promising disposal methods to treat organic waste. Also, a feasible management is necessary for the resulted digestate. Hydrothermal carbonization (HTC) combination with pyrolysis could be a proper solution to use for the treatment of digestate. In this study, the effect of an HTC on the pyrolysis of the digestate of agricultural waste (AWD) was investigated, focusing on the kinetic and thermodynamic aspects. Three model-free methods, including Friedman, KAS, and OFW methods, were used to evaluate the kinetic performance of the total and pseudo pyrolytic reactions of AWD and its hydrochar. Furthermore, kinetic predictions were made to provide more information for further studies. It was found that the HTC treatment decreased the activation energy ranges of the pyrolysis of AWD from 182.9-274.43 kJ/mol to 144.59-205.20 kJ/mol by using the Friedman method. For a more thorough understanding of the effect of HTC treatment on the pyrolysis of AWD, the pyrolysis reactions of AWD and its hydrochar were divided into two pseudoreactions using the Fraser-Suzuki deconvolution method. The mean activation energy of the deduced pseudo 2 pyrolytic reaction of hydrochar was 175.64 kJ/mol, which was 28.11 kJ/mol less than that of AWD. In addition, the Delta H(double dagger )values of the pseudo 2 reactions of AWD and its hydrochar were 197.97 and 169.68 kJ/mol, respectively. The results of kinetic isothermal predictions suggested that the peak temperature for the further research and application of the pyrolysis of AWD and its hydmchar should not be lower than 450 degrees C.
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