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Biomass and Waste Conversion: Latest Advances and Prospects

A special issue of Energies (ISSN 1996-1073). This special issue belongs to the section "A4: Bio-Energy".

Deadline for manuscript submissions: closed (31 July 2023) | Viewed by 19160

Special Issue Editor

Faculty of Energy and Fuels, AGH University of Science and Technology, Mickiewicza 30, 30-059 Krakow, Poland
Interests: biomass; waste; biofuel and biorefinery; thermal processing; ash; corrosion; fouling; slagging; sorbents; adsorption chillers

Special Issue Information

Dear Colleagues,

The natural environment cannot sustain human development anymore, so non-renewable resources must be preserved and used wisely. Till now, many intensive environmental problems have arisen, and many natural boundaries have been crossed due to our actions. Global warming and the depletion of natural resources are becoming a reality. Pollution and climate change are important factors enforcing our society to change their habits and move towards process circularity.

The huge demand for energy, both thermal and electrical, is obvious, but it is not guaranteed anymore. To maintain stability, we have to move towards more eco-friendly solutions and replace fossil fuels with more heterogeneous and challenging fuels such as biomass, especially agricultural biomass, municipal waste and sewage sludge.

The thermochemical processing of waste fuels and biomass includes, but is not limited to: torrefaction, pyrolysis, liquefaction, gasification, hydrothermal carbonization and co-combustion and direct combustion. Nowadays, not only the efficiency of the process is the main challenge, but also waste generation and further utilization of the products to close the material loop is an important issue. One of the major concerns is the quality of the materials generated through the thermal processing of waste and biomass. Product cleaning and upgrading to enhance its properties give a lot of opportunities for research.

The scope of this Special Issue covers all topics associated with biomass and waste conversion technologies together with raw material analysis and further thermal processing products’ upgrading and utilization. Experimental and numerical studies and reviews describing the state of the art are within the scope of this Special Issue.

Dr. Agata Mlonka-Mędrala
Guest Editor

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Keywords

  • biomass
  • waste management
  • municipal waste
  • fuel characterization
  • refuse-derived fuel
  • circular economy
  • sustainability
  • thermal processing
  • torrefaction
  • pyrolysis
  • gasification
  • hydrothermal carbonization
  • combustion
  • hydrogen
  • material recovery
  • energy recovery

Published Papers (11 papers)

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Research

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19 pages, 6445 KiB  
Article
Possibilities of RDF Pyrolysis Products Utilization in the Face of the Energy Crisis
by Magdalena Skrzyniarz, Marcin Sajdak, Monika Zajemska, Anna Biniek-Poskart, Józef Iwaszko and Andrzej Skibiński
Energies 2023, 16(18), 6695; https://doi.org/10.3390/en16186695 - 19 Sep 2023
Cited by 1 | Viewed by 1354
Abstract
The main goal of the study was to assess the possibility of practical use of products of pyrolysis of refuse-derived fuel (RDF), i.e., pyrolysis gas, biochar and pyrolysis oil, as an alternative to standard fossil fuels. The subject matter of the paper reaches [...] Read more.
The main goal of the study was to assess the possibility of practical use of products of pyrolysis of refuse-derived fuel (RDF), i.e., pyrolysis gas, biochar and pyrolysis oil, as an alternative to standard fossil fuels. The subject matter of the paper reaches out to the challenges faced by the global economy, not only in the context of the energy crisis, but also in the context of the energy transformation currently beginning in Europe. The increase in fuel and energy prices prompts countries to look for alternative solutions to Russian minerals. At the same time, the growing amount of municipal waste forces the implementation of solutions based on energy recovery (the amount of municipal waste per EU inhabitant in 2021 is 530 kg). One such solution is pyrolysis of RDF, i.e., fuels produced from the over-sieve fraction of municipal waste. In Poland, insufficient processing capacity of thermal waste conversion plants has led to significant surpluses of RDF (1.2 million Mg of undeveloped RDF in Poland in 2021). RDF, due to their high calorific value, can be a valuable energy resource (16–18 MJ/k). This issue is analyzed in this study. Full article
(This article belongs to the Special Issue Biomass and Waste Conversion: Latest Advances and Prospects)
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16 pages, 3146 KiB  
Article
Treatment of Liquid Fraction of Digestate by Integrated Process Struvite Precipitation—Forward Osmosis
by Agnieszka Urbanowska, Izabela Polowczyk and Małgorzata Kabsch-Korbutowicz
Energies 2023, 16(1), 47; https://doi.org/10.3390/en16010047 - 21 Dec 2022
Viewed by 1293
Abstract
The research undertaken in this paper was aimed at determining the effect of struvite precipitation, one of the potential products that can be obtained during digestate management, on the performance of the non-pressurized membrane process—forward osmosis (FO). The effect of using an integrated [...] Read more.
The research undertaken in this paper was aimed at determining the effect of struvite precipitation, one of the potential products that can be obtained during digestate management, on the performance of the non-pressurized membrane process—forward osmosis (FO). The effect of using an integrated struvite precipitation—forward osmosis process to treat the digestate liquid on the changes in the properties of organic substances present in the treated solution (particle size distribution, ζ-potential) was analysed as well. The study was conducted for the liquid fraction of municipal waste biogas plant digestate. The obtained results demonstrate the suitability of this process for recovering water from liquid digestate. It was found that forward osmosis conducted for a digestate pre-treated by chemical struvite precipitation leads to higher water flux values and increased salt concentration in the receiving solution (from 0.5 to 3 mol/dm3 NaCl). There is practically no concomitant infiltration of organic substances into the receiving solution. Therefore, the use of 3 mol/dm3 NaCl as a draw solution results in the recovery of the highest volume of water per unit of time. An analysis of the particle size distribution shows that the removal of the macromolecular fraction of organic compounds from the digestate mainly takes place simultaneously with the chemical precipitation of struvite. It was found that an increase in the concentration of the draw solution, which allows for greater water recovery, resulted in the aggregation of the concentrated organic molecules. Full article
(This article belongs to the Special Issue Biomass and Waste Conversion: Latest Advances and Prospects)
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15 pages, 4111 KiB  
Article
Possibilities of Using Zeolites Synthesized from Fly Ash in Adsorption Chillers
by Agata Mlonka-Mędrala, Tarikul Hasan, Wojciech Kalawa, Marcin Sowa, Karol Sztekler, Moises Luzia Pinto and Łukasz Mika
Energies 2022, 15(19), 7444; https://doi.org/10.3390/en15197444 - 10 Oct 2022
Cited by 3 | Viewed by 1213
Abstract
Adsorption chillers produce cold energy, using heat instead of electricity, thus reducing electrical energy consumption. A major industrial waste, fly ash, can be converted to zeolite and used in adsorption chillers as an adsorbent. In this research, three different types of zeolites were [...] Read more.
Adsorption chillers produce cold energy, using heat instead of electricity, thus reducing electrical energy consumption. A major industrial waste, fly ash, can be converted to zeolite and used in adsorption chillers as an adsorbent. In this research, three different types of zeolites were synthesised from fly ash via a hydrothermal reaction in an alkaline solution (NaOH). The obtained samples (Na-A zeolites) were modified with K2CO3 to increase the water adsorption capacity of these samples. Phase and morphology analyses shows that desired zeolites formed properly but other crystalline phases also exist along with nonporous amorphous phases. The determined specific surface areas for Na-A zeolite (12 h) and Na-A zeolite (24 h) are 45 m2/g and 185 m2/g respectively, while the specific surface area for synthesized 13X zeolite is almost negligible. Water-isotherm for each of these samples was measured. Considering the application of adsorption chillers, average adsorption capacity was very low, 1.73% and 1.27%, respectively, for the two most probable operating conditions for synthesized 13X zeolite, whereas no water was available for the evaporation from Na-A zeolite (12 h) and Na-A zeolite (24 h). This analysis implies that among the synthesized materials only 13X zeolite has a potential as an adsorber in sorption chillers. Full article
(This article belongs to the Special Issue Biomass and Waste Conversion: Latest Advances and Prospects)
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15 pages, 32403 KiB  
Article
Hydrothermal Carbonization of the Wet Fraction from Mixed Municipal Solid Waste: A Fuel and Structural Analysis of Hydrochars
by Maciej Śliz, Klaudia Czerwińska, Aneta Magdziarz, Lidia Lombardi and Małgorzata Wilk
Energies 2022, 15(18), 6708; https://doi.org/10.3390/en15186708 - 14 Sep 2022
Cited by 9 | Viewed by 1418
Abstract
One of the by-products of a mechanical-biological waste treatment plant is the under-sieve fraction, which requires separation prior to further processing of municipal mixed waste. This stream usually follows the fate of landfilling. Instead, it could be introduced to the hydrothermal carbonization (HTC) [...] Read more.
One of the by-products of a mechanical-biological waste treatment plant is the under-sieve fraction, which requires separation prior to further processing of municipal mixed waste. This stream usually follows the fate of landfilling. Instead, it could be introduced to the hydrothermal carbonization (HTC) process to improve its fuel properties and become solid recovered fuel. The organic fraction and high moisture content (approximately 26%) of under-sieve fraction are favorable properties for the HTC process. In this study, hydrochars, the solid product of HTC, were produced at 200 and 220 °C with residence times of 1, 4, and 8 h. The main aim of this investigation was to establish the influence of different process parameters on hydrochars’ fuel properties. Thermogravimetric analysis (TGA), Fourier-transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM) were employed in the analyses. The results confirmed the positive effects of hydrothermal carbonization on the under-sieve fraction of municipal mixed waste properties. The ignition temperature increased from 247 °C to 288 °C and burnout temperature decreased to 443 °C from 489 °C after hydrothermal carbonization, causing a shorter combustion process. The determined key combustion parameters were: S = 12.4 × 10−8%·min−2·°C−3, Hf = 1174.9 °C and Di = 0.0075%·min−3, which in comparison to USF decreased by 44%, increased by 33%, and decreased by 29%, respectively, and became closer to those of coal. Furthermore, the identified structural changes indicate that hydrochars could be successfully used in energy production. The most promising results were found for hydrochar produced at 220 °C for 1 h, leading to a better combustion performance and providing a more stable and a less violent flame. Full article
(This article belongs to the Special Issue Biomass and Waste Conversion: Latest Advances and Prospects)
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17 pages, 14830 KiB  
Article
Hydrothermal Carbonization Process of Digestate from Sewage Sludge: Chemical and Physical Properties of Hydrochar in Terms of Energy Application
by Małgorzata Wilk, Marcin Gajek, Maciej Śliz, Klaudia Czerwińska and Lidia Lombardi
Energies 2022, 15(18), 6499; https://doi.org/10.3390/en15186499 - 06 Sep 2022
Cited by 9 | Viewed by 1422
Abstract
Hydrochars (HTCD) derived from digestates, namely D1 and D2 (from two plants) of sewage sludge, were examined with respect to their fuel properties. The hydrothermal carbonization (HTC) tests were performed at temperatures of 200 and 220 °C, for 2 and 4 h of [...] Read more.
Hydrochars (HTCD) derived from digestates, namely D1 and D2 (from two plants) of sewage sludge, were examined with respect to their fuel properties. The hydrothermal carbonization (HTC) tests were performed at temperatures of 200 and 220 °C, for 2 and 4 h of residence times, and with 1:10 and 1:8 digestate to water ratios (D/W), causing an increase of ash content (max. 55.8%), and a decrease c.a. 20% of the higher heating value except for a slight increase to 15 kJ/kg at 200 °C and 4 h in hydrochars. Conversely, the combustion profiles of hydrochars moved towards higher temperatures (225–257 °C) and finished earlier at lower temperatures (423–438 °C). The HTCD from D1 and D2 showed very similar properties under the same conditions (200 °C, 4 h, 1:8 D/W) for combustion characteristic temperatures, indices and profiles. The best efficiency was found for HTCD2. In addition, the polluted post-processing liquid phase was treated by a distillation process providing 30% higher pH, 50% lower BOD values, up to 15 times lower COD values, and c.a. three times lower conductivity. Full article
(This article belongs to the Special Issue Biomass and Waste Conversion: Latest Advances and Prospects)
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19 pages, 3960 KiB  
Article
Evaluation of Physical and Chemical Properties of Residue from Gasification of Biomass Wastes
by Małgorzata Sieradzka, Agata Mlonka-Mędrala, Izabela Kalemba-Rec, Markus Reinmöller, Felix Küster, Wojciech Kalawa and Aneta Magdziarz
Energies 2022, 15(10), 3539; https://doi.org/10.3390/en15103539 - 12 May 2022
Cited by 6 | Viewed by 1802
Abstract
Thermochemical conversion of biomass waste is a high potential option for increasing usage of renewable energy sources and transferring wastes into the circular economy. This work focuses on the evaluation of the energetic and adsorption properties of solid residue (char) of the gasification [...] Read more.
Thermochemical conversion of biomass waste is a high potential option for increasing usage of renewable energy sources and transferring wastes into the circular economy. This work focuses on the evaluation of the energetic and adsorption properties of solid residue (char) of the gasification process. Gasification experiments of biomass wastes (wheat straw, hay and pine sawdust) were carried out in a vertical fixed bed reactor, under a CO2 atmosphere and at various temperatures (800, 900 and 1000 °C). The analysis of the energy properties of the obtained chars included elemental and thermogravimetric (TGA) analysis. TGA results indicated that the chars have properties similar to those of coal; subjected data were used to calculate key combustion parameters. As part of the analysis of adsorption properties, BET, SEM, FTIR and dynamic methanol vapor sorption tests were conducted. The specific surface area has risen from 0.42–1.91 m2/g (biomass) to 419–891 m2/g (char). FTIR spectroscopy confirmed the influence of gasification on the decomposition of characteristic chemical compounds for biomass. Methanol sorption has revealed for the 900 °C chars of pine sawdust the highest sorption capacity and its mass change was 24.15% at P/P0 = 90%. Selected chars might be an appropriate material for volatile organic compounds sorption. Full article
(This article belongs to the Special Issue Biomass and Waste Conversion: Latest Advances and Prospects)
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17 pages, 4963 KiB  
Article
Plastic Waste Management towards Energy Recovery during the COVID-19 Pandemic: The Example of Protective Face Mask Pyrolysis
by Magdalena Skrzyniarz, Marcin Sajdak, Monika Zajemska, Józef Iwaszko, Anna Biniek-Poskart, Andrzej Skibiński, Sławomir Morel and Paweł Niegodajew
Energies 2022, 15(7), 2629; https://doi.org/10.3390/en15072629 - 03 Apr 2022
Cited by 14 | Viewed by 2981
Abstract
This paper presents an assessment of the impact of the COVID-19 pandemic on the waste management sector, and then, based on laboratory tests and computer calculations, indicates how to effectively manage selected waste generated during the pandemic. Elemental compositions—namely, C, H, N, S, [...] Read more.
This paper presents an assessment of the impact of the COVID-19 pandemic on the waste management sector, and then, based on laboratory tests and computer calculations, indicates how to effectively manage selected waste generated during the pandemic. Elemental compositions—namely, C, H, N, S, Cl, and O—were determined as part of the laboratory tests, and the pyrolysis processes of the above wastes were analysed using the TGA technique. The calculations were performed for a pilot pyrolysis reactor with a continuous flow of 240 kg/h in the temperature range of 400–900 °C. The implemented calculation model was experimentally verified for the conditions of the refuse-derived fuel (RDF) pyrolysis process. As a result of the laboratory tests and computer simulations, comprehensive knowledge was obtained about the pyrolysis of protective masks, with particular emphasis on the gaseous products of this process. The high calorific value of the pyrolysis gas, amounting to approx. 47.7 MJ/m3, encourages the management of plastic waste towards energy recovery. The proposed approach may be helpful in the initial assessment of the possibility of using energy from waste, depending on its elemental composition, as well as in the assessment of the environmental effects. Full article
(This article belongs to the Special Issue Biomass and Waste Conversion: Latest Advances and Prospects)
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17 pages, 2698 KiB  
Article
Intermediate Pyrolysis of Brewer’s Spent Grain: Impact of Gas Atmosphere
by Artur Bieniek, Wojciech Jerzak, Małgorzata Sieradzka, Łukasz Mika, Karol Sztekler and Aneta Magdziarz
Energies 2022, 15(7), 2491; https://doi.org/10.3390/en15072491 - 28 Mar 2022
Cited by 12 | Viewed by 2062
Abstract
This work focuses on the impact of carrier gas on the quantity and quality of pyrolytic products received from intermediate pyrolysis of the brewer’s spent grain. In this study, three types of carrier gases were tested: argon, nitrogen, and carbon dioxide at three [...] Read more.
This work focuses on the impact of carrier gas on the quantity and quality of pyrolytic products received from intermediate pyrolysis of the brewer’s spent grain. In this study, three types of carrier gases were tested: argon, nitrogen, and carbon dioxide at three temperatures of 500, 600, and 700 °C. On the basis of the process conditions, the yield of products was determined. The ultimate analysis of the char was performed, and for selected chars, the combustion properties were determined. Gas chromatography of the organic fraction of oil was performed, and the compounds were determined. Additionally, microscale investigation of the spent grain pyrolysis was performed by thermogravimetric analysis. The results showed that there were no significant differences in product yields in various atmospheres. Char yield changed only with temperature from 28% at 500 °C up to 19% at 700 °C. According to ultimate analysis, the char from CO2 pyrolysis was approximately 2% richer in carbon and this fact did not influence on the combustion properties of the char. The oil fraction was characterized mainly by acids with a maximum content of 68% at 600 °C in an argon atmosphere and the acid concentration depended on the carrier gas as follows line: Ar > N2 > CO2. Full article
(This article belongs to the Special Issue Biomass and Waste Conversion: Latest Advances and Prospects)
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15 pages, 2456 KiB  
Article
Properties of Animal-Origin Ash—A Valuable Material for Circular Economy
by Izabella Maj, Sylwester Kalisz and Szymon Ciukaj
Energies 2022, 15(4), 1274; https://doi.org/10.3390/en15041274 - 10 Feb 2022
Cited by 13 | Viewed by 1714
Abstract
In the presented paper, two types of animal-origin biomass, cow dung and chicken litter, are characterized in terms of combustion-related problems and ash properties. It was found that these parameters strongly depend on the farming style. Whether it is cow dung or chicken [...] Read more.
In the presented paper, two types of animal-origin biomass, cow dung and chicken litter, are characterized in terms of combustion-related problems and ash properties. It was found that these parameters strongly depend on the farming style. Whether it is cow dung or chicken litter, free-range raw materials are characterized by higher ash contents than industrial farming ones. Free-range samples contain chlorine at lower levels, while industrial farming samples are chlorine rich. Free-range samples are characterized by the predominant content of silica in the ash: 75.60% in cow dung and 57.11% in chicken litter, while industrial farming samples contain more calcium. Samples were classified by 11 “slagging indices” based on the ash and fuel composition to evaluate their tendencies for slagging, fouling, ash deposition and bed agglomeration. Furthermore, an assessment was made against the current EU law regulations, whether the ashes can be component materials for fertilizers. The phosphorus concentration in the investigated ashes corresponds to 4.09–23.73 wt% P2O5 and is significantly higher in industrial chicken litter samples. The concentrations of Hg, Cu, As, Ni, Cd and Pb in all samples are below the limits of the UE regulations. However, concentrations of Cr in all samples and Zn in industrial chicken litter exceed these standards. Full article
(This article belongs to the Special Issue Biomass and Waste Conversion: Latest Advances and Prospects)
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Review

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21 pages, 1963 KiB  
Review
Recent Findings on Fly Ash-Derived Zeolites Synthesis and Utilization According to the Circular Economy Concept
by Agata Mlonka-Mędrala
Energies 2023, 16(18), 6593; https://doi.org/10.3390/en16186593 - 13 Sep 2023
Cited by 2 | Viewed by 1453
Abstract
The synthesis and utilization of zeolites derived from fly ash (FA) gained significant attention years ago due to their potential to address environmental challenges and promote sustainable practices subscribing to the circular economy concept. This paper highlights the recent findings regarding the synthesis [...] Read more.
The synthesis and utilization of zeolites derived from fly ash (FA) gained significant attention years ago due to their potential to address environmental challenges and promote sustainable practices subscribing to the circular economy concept. This paper highlights the recent findings regarding the synthesis and utilization of zeolites derived from FA. It begins with a discussion about the recent challenges regarding industrial waste management and statistics regarding its availability on the global market with a special insight into the situation in Poland. The characteristics of FA obtained from various fuels were presented and the main differences were highlighted. Then, different methods used for the synthesis of zeolites from FA were discussed in small and pilot scales taking into consideration the main challenges and problems. The analytical methods used in porous materials synthesis verification and properties determination were described. The sorption properties of FA-derived zeolites were presented and discussed. Finally, the paper emphasizes the potential applications of fly ash-derived zeolites in different fields. Their importance as sustainable alternatives to conventional materials in industry, construction, agriculture, power, medicine, and other industrial sectors was analyzed. Full article
(This article belongs to the Special Issue Biomass and Waste Conversion: Latest Advances and Prospects)
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Other

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9 pages, 887 KiB  
Brief Report
Hydrothermal Carbonisation as Treatment for Effective Moisture Removal from Digestate—Mechanical Dewatering, Flashing-Off, and Condensates’ Processing
by Halina Pawlak-Kruczek, Agnieszka Urbanowska, Lukasz Niedzwiecki, Michał Czerep, Marcin Baranowski, Christian Aragon-Briceño, Małgorzata Kabsch-Korbutowicz, Amit Arora, Przemysław Seruga, Mateusz Wnukowski, Jakub Mularski, Eddy Bramer, Gerrit Brem and Artur Pożarlik
Energies 2023, 16(13), 5102; https://doi.org/10.3390/en16135102 - 01 Jul 2023
Viewed by 968
Abstract
One of the processes that can serve to valorise low-quality biomass and organic waste is hydrothermal carbonization (HTC). It is a thermochemical process that transpires in the presence of water and uses heat to convert wet feedstocks into hydrochar (the solid product of [...] Read more.
One of the processes that can serve to valorise low-quality biomass and organic waste is hydrothermal carbonization (HTC). It is a thermochemical process that transpires in the presence of water and uses heat to convert wet feedstocks into hydrochar (the solid product of hydrothermal carbonization). In the present experimental study, an improvement consisting of an increased hydrophobic character of HTC-treated biomass is demonstrated through the presentation of enhanced mechanical dewatering at different pressures due to HTC valorisation. As part of this work’s scope, flashing-off of low-quality steam is additionally explored, allowing for the recovery of the physical enthalpy of hot hydrochar slurry. The flashing-off vapours, apart from steam, contain condensable hydrocarbons. Accordingly, a membrane system that purifies such effluent and the subsequent recovery of chemical energy from the retentate are taken into account. Moreover, the biomethane potential is calculated for the condensates, presenting the possibility for the chemical energy recovery of the condensates. Full article
(This article belongs to the Special Issue Biomass and Waste Conversion: Latest Advances and Prospects)
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