Thermal Treatment of Biomass and Solid Municipal Waste

A special issue of ChemEngineering (ISSN 2305-7084).

Deadline for manuscript submissions: closed (28 February 2023) | Viewed by 12525

Special Issue Editors

Department of Energy and Process Engineering, Norwegian University of Science and Technology, 7491 Trondheim, Norway
Interests: renewable and alternative fuels; CFD; stochastic reactor modeling; detailed chemistry and surrogates; emissions; waste-to-energy
Institute of Sciences and Technologies for Sustainable Energy and Mobility (STEMS), National Research Council, Naples, Italy
Interests: thermochemical conversion processes; pyrolysis; torrefaction; biomass; waste valorization; biomass valorization from phytoremediation; heavy metals; inorganic; biochar
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Special Issue Information

Dear Colleagues,

The local conversion of municipal, industrial, and biomass wastes is a key element of our future power supply, renewable resource chains, and waste management strategies. Thermal treatment of these resources offers their efficient, comparable cheap usage when direct material recycling is not feasible. Products of thermal treatment, such as pyrolysis, gasification, and incineration, are electricity and heat, high caloric gases, feedstock species for the chemical industry, and biobased solid and liquid products. All products are characterized by higher energy density or value compared to their raw materials and can therefore be efficiently stored, transported, and used.

The variety of the feedstock, e.g., seasonal dependencies, low calorific values, or moisture contents, however, make efficient conversion challenging. To fully integrate these technologies into our value chain, technologies for conversion, cleaning, and upgrading have to be improved. When using incineration, the emitted gases are less climate active than those emitted by landfilling, but any emissions are of concern and have to be minimized.

Thus, there is every reason for biobased products from thermal treatment to contribute to carbon footprint reductions in the energy and transportation fuel production sectors and in the fossil-based materials market. We invite original research articles, as well as reviews and perspective papers, with a focus on the above-described challenges.

Dr. Corinna Netzer
Dr. Corinna Maria Grottola
Guest Editors

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Keywords

  • pyrolysis
  • gasification
  • waste-to-energy
  • biomass-to-energy
  • biomass-to-fuel
  • biomass-to-chemical
  • plastic-derived products
  • municipal solid waste
  • biochar
  • solid, heterogenous, and gas-phase kinetics

Published Papers (5 papers)

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Research

14 pages, 3250 KiB  
Article
Recovery of Polyphenolic Antioxidants from Coffee Silverskin Using Acid-Catalyzed Ethanol Organosolv Treatment
by George Smyrnakis, George Stamoulis, Dimitrios Palaiogiannis, Theodoros Chatzimitakos, Vassilis Athanasiadis, Stavros I. Lalas and Dimitris P. Makris
ChemEngineering 2023, 7(4), 72; https://doi.org/10.3390/chemengineering7040072 - 12 Aug 2023
Cited by 2 | Viewed by 1352
Abstract
The examination presented herein sought to establish a novel methodology for the efficient recovery of polyphenolic antioxidants from coffee processing residues, namely coffee silverskin (CSS). The process developed was an ethanol-based organosolv treatment, assisted by acid catalysis, using sulfuric acid or oxalic acid [...] Read more.
The examination presented herein sought to establish a novel methodology for the efficient recovery of polyphenolic antioxidants from coffee processing residues, namely coffee silverskin (CSS). The process developed was an ethanol-based organosolv treatment, assisted by acid catalysis, using sulfuric acid or oxalic acid as the catalyst. The first approach was modeling treatment based on severity, where it was found that treatment dependence on time and temperature may well be described by linear relationships. Response surface methodology was then deployed as a consecutive stage, to optimize treatments with regard to catalyst concentration and resident time. In this case, again, linear models could effectively predict polyphenol recovery yield (YTP). For the sulfuric-acid-catalyzed treatment, the maximum theoretic YTP was found to be 10.95 ± 0.44 mg caffeic acid equivalent (CAE) g−1 DM, achieved at CSuAc = 1.5% and t = 300 min. On the other hand, the maximum YTP of 10.30 ± 0.53 could be attained at COxAc = 4%, and t = 300 min. Considering treatment severity, it was concluded that the use of oxalic acid, a food-grade organic acid, instead of sulfuric acid, a corrosive acid, would afford equivalent effects at lower severity. The high-performance liquid chromatography analyses also revealed that the extract produced through the oxalic-acid-catalyzed treatment was more enriched in neochlorogenic and chlorogenic acids, and it exhibited stronger antiradical activity, but weaker ferric-reducing effects. It is proposed that the methodology developed may contribute towards the use of coffee processing wastes as potential sources of bioactive ingredients and the design of novel functional products, in the frame of a more sustainable strategy for coffee processing companies. Full article
(This article belongs to the Special Issue Thermal Treatment of Biomass and Solid Municipal Waste)
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11 pages, 2375 KiB  
Article
Mathematical Modeling and Experiments on Pyrolysis of Walnut Shells Using a Fixed-Bed Reactor
by Aysan Safavi, Christiaan Richter and Runar Unnthorsson
ChemEngineering 2022, 6(6), 93; https://doi.org/10.3390/chemengineering6060093 - 01 Dec 2022
Cited by 6 | Viewed by 2451
Abstract
Pyrolysis is a low-emission and sustainable thermochemical technique used in the production of biofuels, which can be used as an alternative to fossil fuels. Understanding the kinetic characterization of biomass pyrolysis is essential for process upscaling and optimization. There is no accepted model [...] Read more.
Pyrolysis is a low-emission and sustainable thermochemical technique used in the production of biofuels, which can be used as an alternative to fossil fuels. Understanding the kinetic characterization of biomass pyrolysis is essential for process upscaling and optimization. There is no accepted model that can predict pyrolysis kinetics over a wide range of pyrolysis conditions and biomass types. This study investigates whether or not the classical lumped kinetic model with a three-competitive reaction scheme can accurately predict the walnut shell pyrolysis product yields. The experimental data were obtained from walnut shell pyrolysis experiments at different temperatures (300–600 °C) using a fixed-bed reactor. The chosen reaction scheme was in good agreement with our experimental data for low temperatures, where the primary degradation of biomass occurred (300 and 400 °C). However, at higher temperatures, there was less agreement with the model, indicating that some other reactions may occur at such temperatures. Hence, further studies are needed to investigate the use of detailed reaction schemes to accurately predict the char, tar, and gas yields for all types of biomass pyrolysis. Full article
(This article belongs to the Special Issue Thermal Treatment of Biomass and Solid Municipal Waste)
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12 pages, 2472 KiB  
Article
Influence of Pyrolysis Temperature on Biochar Produced from Lignin–Rich Biorefinery Residue
by Corinna Maria Grottola, Paola Giudicianni, Fernando Stanzione and Raffaele Ragucci
ChemEngineering 2022, 6(5), 76; https://doi.org/10.3390/chemengineering6050076 - 02 Oct 2022
Cited by 2 | Viewed by 1784
Abstract
The biorefinery concept is growing rapidly for bio-based production of fuels and products, and steam explosion is by far the most applied pre-treatment technology allowing the delignification of lignocellulosic biomass. Within the bioethanol production process, pyrolysis of lignin-rich residue (LRR), for producing char [...] Read more.
The biorefinery concept is growing rapidly for bio-based production of fuels and products, and steam explosion is by far the most applied pre-treatment technology allowing the delignification of lignocellulosic biomass. Within the bioethanol production process, pyrolysis of lignin-rich residue (LRR), for producing char to be used in a wide variety of applications, presents a viable way to recover materials and energy, helping to improve the sustainability of the whole production chain. In the present study, it is shown that yields, elemental composition and porosity characteristics of LLR-char are significantly different from those of char produced from alkali lignin. Both products yields and char composition were more similar to the typical values of woody and herbaceous biomasses. The chemical characterization of the chars’ organic matrices as well as the content of the main inorganic species suggest the opportunity to perform pyrolysis at low temperatures for producing high yields of chars suitable to be used as carbon sink or soil fertilizers. The BET values of the chars obtained at final temperatures in the range 500–700 °C seem to be promising for char-application processes involving surface phenomena (e.g., adsorption, catalyst support), thus encouraging further analyses of char-surface chemistry. Full article
(This article belongs to the Special Issue Thermal Treatment of Biomass and Solid Municipal Waste)
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15 pages, 4159 KiB  
Article
Process Optimization and Stability of Waste Orange Peel Polyphenols in Extracts Obtained with Organosolv Thermal Treatment Using Glycerol-Based Solvents
by Rehab Abdoun, Spyros Grigorakis, Abdessamie Kellil, Sofia Loupassaki and Dimitris P. Makris
ChemEngineering 2022, 6(3), 35; https://doi.org/10.3390/chemengineering6030035 - 07 May 2022
Cited by 11 | Viewed by 2319
Abstract
This study was focused on the simultaneous organosolv treatment/extraction of waste orange peels (WOP) for the effective recovery of polyphenolic antioxidants. The treatments were performed with aqueous glycerol mixtures, which were acidified either with citric acid or hydrochloric acid (HCl). Process optimization was [...] Read more.
This study was focused on the simultaneous organosolv treatment/extraction of waste orange peels (WOP) for the effective recovery of polyphenolic antioxidants. The treatments were performed with aqueous glycerol mixtures, which were acidified either with citric acid or hydrochloric acid (HCl). Process optimization was carried out using response surface methodology and comparative appraisal of the different processes tested, based on both the extraction efficiency factor (FEE), severity factor (SF) or combined severity factor (CSF). Metabolite stability was also of major concern, and it was examined by deploying liquid chromatography-mass spectrometry. The results drawn suggested 90% (w/w) glycerol to be the highest-performing system, providing a yield in total polyphenols of 44.09 ± 5.46 mg GAE g−1 DM at 140 °C for 50 min, with a FEE of 2.20 and an SF of 2.88. Acidification with 1% citric acid was proven less efficient and equally severe, whereas acidification with 1% HCl was less severe but also less efficient. The major disadvantage associated with the use of HCl was its detrimental impact on the polyphenolic composition of WOP since major metabolites, such as narirutin, hesperidin and didymin, did not survive the process. By contrast, the formation of lower molecular weight compounds was observed. With regard to antioxidant properties, the extract obtained with aqueous glycerol displayed significantly higher antiradical activity and reducing power, which was in line with its higher concentration in total polyphenols. It was concluded that organosolv treatment with aqueous glycerol under the conditions employed may boost polyphenol recovery from WOP, thus giving extracts with powerful antioxidant characteristics. Full article
(This article belongs to the Special Issue Thermal Treatment of Biomass and Solid Municipal Waste)
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18 pages, 3977 KiB  
Article
Chemical Model for Thermal Treatment of Sewage Sludge
by Corinna Netzer and Terese Løvås
ChemEngineering 2022, 6(1), 16; https://doi.org/10.3390/chemengineering6010016 - 07 Feb 2022
Cited by 6 | Viewed by 2887
Abstract
Sewage sludge is here studied as a valuable source for processing or energy conversation thanks to its high nutrition and energy content. However, various origins of the wastewater, different water cleaning technologies, and seasonal and regional dependencies lead to the high variability of [...] Read more.
Sewage sludge is here studied as a valuable source for processing or energy conversation thanks to its high nutrition and energy content. However, various origins of the wastewater, different water cleaning technologies, and seasonal and regional dependencies lead to the high variability of the sewage sludge properties. In thermal treatment units, that is, incineration, gasification and pyrolysis, sewage sludge serves as feedstock or fuel, hence a proper characterization and a mathematical description of the sewage sludge are required to estimate product streams and to formulate numerical simulations and optimization methods. The presented work introduces a surrogate concept that allows replication of sewage sludge’s ultimate composition, moisture, and ash content. The surrogate approach aims to model the decomposition of any sewage sludge sample, opposite to the established determination of kinetic rates for individual samples. Based on chemical solid surrogate species and corresponding reaction mechanisms, the thermal decomposition path is described. Sewage sludge is represented by a combination of lignocellulosic species, proteins, sugars, lipids, and representative inorganic species. The devolatilization and heterogeneous reactions are formulated such that they can be used together with a detailed gas-phase model, including tar oxidation and emission models for nitrogen and sulfur oxides, recently proposed by the authors. The developed chemical model is applied using a zero-dimensional gasification reactor in order to model weight loss within the thermogravimetric analysis, pyrolysis, gasification and combustion conditions. Weight loss, the composition of product gases, and emission release (nitrogen and sulfur oxides) are captured well by the model. The flexible surrogate approach allows us to represent various sewage sludge samples. Full article
(This article belongs to the Special Issue Thermal Treatment of Biomass and Solid Municipal Waste)
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