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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-Kruczek, Halina, et al.
(author)
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Industrial Process Description for the Recovery of Agricultural Water From Digestate
- 2020
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In: Journal of energy resources technology. - : ASME International. - 0195-0738 .- 1528-8994. ; 142:7
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Journal article (peer-reviewed)abstract
- Currently, the reclamation and reuse of water have not reached their full potential, although more energy is needed to obtain and transport freshwater and this solution has a more serious environmental impact. Agricultural irrigation is, by far, the largest application of reclaimed water worldwide, so the proposed concept may result in the production of water that can be used, among others, for crop irrigation. This paper describes a novel installation for the recovery of the agricultural water from the digestate, along with the results of initial experiments. Currently, water is wasted, due to evaporation, in anaerobic digestion plants, as the effluent from dewatering of the digestate is discharged into lagoons. Moreover, water that stays within the interstitial space of the digestate is lost in a similar fashion. With increasing scarcity of water in rural areas, such waste should not be neglected. The study indicates that hydrothermal carbonization (HTC) enhances mechanical dewatering of the agricultural digestate and approximately 900 L of water can be recovered from one ton. Dewatered hydrochars had a lower heating value of almost 10 MJ/kg, indicating the possibility of using it as a fuel for the process. The aim of this Design Innovation Paper is to outline the newly developed concept of an installation that could enable recovery of water from, so far, the neglected resource-i.e., digestate from anaerobic digestion plants.
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