Browsing by Subject "hydrochar"

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Access status: Open Access ,
Fuel properties characterization of hydrochars derived from agricultural digestate
(2025) Mikusińska, Joanna ; Szkadłubowicz, Klaudia ; Prus, Zuzanna ; Kuźnia, Monika; Gajek, Marcin; Wilk, Małgorzata
Wydział Inżynierii Metali i Informatyki Przemysłowej
Agricultural digestate is a by–product of biogas plant processes. Its composition is variable and depends on the type of raw feedstock used. Due to its high moisture content the digestate is suitable for hydrothermal carbonization (HTC). The HTC process is performed in a reactor where the feedstock is heated to a high temperature in an aqueous environment. As a result of the reaction, a solid product, process water and a gaseous product are generated. The gaseous product is obtained in trace amounts unlike the process water where the amount is significant. The rich in carbon solid product of the HTC process is hydrochar. Hydrochars can be used as an alternative to non–renewable fossil fuels. The aim of this paper was to investigate and characterize hydrochars derived from agricultural digestate at 190 ◦C, 200 ◦C and 210 ◦C and residence times of: 0.5, 1, 1.5, and 2 h. In addition, the fuel properties and combustion performance supported by an activation energy determination were evaluated. In brief, it was found that a higher temperature and longer residence time produced a more carbonaceous biofuel.
Access status: Open Access ,
Hydrothermal carbonization of digestate produced in the biogas production process
(2023) Mikusińska, Joanna; Kuźnia, Monika; Czerwińska, Klaudia; Wilk, Małgorzata
Wydział Inżynierii Metali i Informatyki Przemysłowej
In agricultural biogas plants, besides biogas, the by-product digestate is also produced. Due to its high moisture content and organic origin, it can successfully be applied in the hydrothermal carbonization process to avoid the fate of landfilling. This paper reviews the properties of agricultural digestate and its hydrothermal conversion (HTC) into hydrochar and process water. The type of feedstock and the parameters of the HTC process, such as temperature, pressure and residence time, affects the physical and chemical characteristics of hydrochar. Therefore, its possible application might be as a biofuel, fertilizer, soil improver, adsorber, or catalyst. In this paper, the properties of hydrochar derived from agricultural digestate are widely discussed.
Access status: Open Access ,
Improvements in dewaterability and fuel properties of hydrochars derived from hydrothermal co-carbonization of sewage sludge and organic waste
(2024) Wilk, Małgorzata; Śliz, Maciej; Czerwińska, Klaudia; Gajek, Marcin; Kalemba-Rec, Izabela
Wydział Inżynierii Metali i Informatyki Przemysłowej
The hydrothermal co-carbonization of sewage sludge and organic additives, namely 10 and 20 % of charcoal, fir, grass, and an undersieved fraction of municipal solid waste, was studied. The benefits of this combined process included the spectacular dewaterability performance of slurry, proved by positive filtration tests and shorter capillary suction times. For instance, a 20 % fir addition decreased c.a. 60 % of pressure filtration time when compared to the hydrothermal carbonization of sewage sludge. A 10 % undersieved fraction of municipal solid waste resulted in 15.72 s of capillary suction time. Moreover, hydrothermal co-carbonization produced effective solid energy sources. The addition of organic origin waste to sewage sludge prior to the process caused higher heating values, carbon and fixed carbon contents of hydrochars (e.g. a 20 % charcoal addition generated 21 % higher heating value, 30 % carbon and 2.8 times higher fixed carbon), which corresponded with easier and more stable combustion processes compared to hydrochar from sewage sludge determined by thermal analysis. Possible exploitation problems during combustion have been assessed by determining the tendency risks of slagging and fouling based on oxides identified in ash by XRF analysis. Furthermore, changes in the structural and morphological properties of hydrochars were identified by SEM and FTIR analyses.
Access status: Open Access ,
The effect of an acid catalyst on the hydrothermal carbonization of sewage sludge
(2023) Wilk, Małgorzata; Śliz, Maciej; Czerwińska, Klaudia; Śledź, Małgorzata
This research is focused on the addition of a catalyst, sulphuric acid (VI), to sewage sludge, and its effect on solid and liquid products resulting from the hydrothermal carbonization process. Consequently, for hydrochars, proximate and ultimate analyses, higher heating value and specific surface area were determined. Additionally, Fourier-transform infrared spectrophotometric and thermogravimetric analyses were conducted. The heavy metal contents in the ash composition of hydrochars were identified by X-ray fluorescence spectrometry. It was confirmed that the catalyst addition changed the structure as well as the physical and chemical properties of hydrochars and their ashes. Regarding post-processing water, both pH value and conductivity were determined and the element composition, including heavy metals, was conducted by the inductively coupled plasma optical emission and mass spectrometry analyses. It was found that the addition of the catalyst caused a decrease in heavy metal contents and an increase of phosphorus compound in filtrates.
Access status: Open Access ,
Thermal upgrading of hydrochar from anaerobic digestion of municipal solid waste organic fraction
(2022) Mlonka-Mędrala, Agata; Sieradzka, Małgorzata; Magdziarz, Aneta
Wydział Inżynierii Metali i Informatyki Przemysłowej
Solid fraction obtained from anaerobic digestion of municipal solid waste organic fraction is a waste produced in noticeable amounts, which according to circular economy concept can be upgraded to produce new, value-added products like: hydrogen rich process gas and carbon rich solid material. In this study, thermal upgrading of hydrochar by steam gasification was analysed. Raw material was obtained through hydrothermal carbonization (HTC) of digestate from anaerobic digestion of wet fraction of municipal solid waste at 200 and 230 °C, and residence time of 60 and 120 min. The further gasification step was carried out at 800 °C and the residence time was 10 min under nitrogen with a steam atmosphere. The main objective of hydrochar upgrading through steam gasification was production of carbon-rich material with developed active surface area. The study presented promising results regarding proper management of mixed wastes, which have not yet been analysed in the literature. It was noted that low temperature and residence time are favouring active surface area development. Analysis of the main gaseous products of the gasification process showed that syngas is composed mainly of $H_{2}$, $CH_{4}$, $CO_{2}$, $O_{2}$, and $CO$. The hydrogen concentration was the highest noted for hydrochar obtained at highest temperature and residence time. Analysis of the concentration of each syngas component reveals that combined treatment of digestate from anaerobic digestion through the HTC and gasification process results in $H_{2}$-rich syngas products and a high $H_{2}/CO$ ratio with parallel fair quality activated carbon.