Research

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14 pages, 20995 KiB

Open AccessFeature PaperArticle

Experimental Study of Model Refuse-Derived Fuel Pellets Swelling during Heating and Combustion

by Igor Donskoy and Denis Svishchev

Processes 2023, 11(4), 995; https://0-doi-org.brum.beds.ac.uk/10.3390/pr11040995 - 24 Mar 2023

Cited by 1 | Viewed by 1200

Composites of sawdust and crushed polyethylene were obtained by pressing at 5–10 atm. The resulting pellets with a size of about 10–20 mm were then burned in airflow in a muffle furnace at a temperature of 800 °C. The combustion process was recorded, [...] Read more.

Composites of sawdust and crushed polyethylene were obtained by pressing at 5–10 atm. The resulting pellets with a size of about 10–20 mm were then burned in airflow in a muffle furnace at a temperature of 800 °C. The combustion process was recorded, and obtained video data were analyzed. The data obtained made it possible to estimate the change in particle size at different stages of combustion. An increase in linear dimensions during conversion was achieved of up to 2 times. Particle swelling led to a decrease in mechanical strength and destruction of particles before complete burnout. Full article

(This article belongs to the Special Issue Biomass Conversion Process and Biorefinery)

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26 pages, 5543 KiB

Open AccessArticle

Finite Rate Reaction Mechanism Adapted for Modelling Pseudo-Equilibrium Pyrolysis of Cellulose

by Tomás Mora Chandía

Processes 2022, 10(10), 2131; https://0-doi-org.brum.beds.ac.uk/10.3390/pr10102131 - 19 Oct 2022

Cited by 1 | Viewed by 1244

Abstract

This manuscript is related to a formulation for modelling cellulose pyrolysis with a pseudo-equilibrium approach. The objective is to model the kinetics of the cellulose pyrolysis with a semi-global mechanism obtained from the literature in order to obtain the yield and the rate [...] Read more.

This manuscript is related to a formulation for modelling cellulose pyrolysis with a pseudo-equilibrium approach. The objective is to model the kinetics of the cellulose pyrolysis with a semi-global mechanism obtained from the literature in order to obtain the yield and the rate of formation, mainly that of char. The pseudo-equilibrium approach consists of the assumption that the solid phase devolatilisation can be described kinetically—at a finite rate—thus preserving the competitive characteristic between the production of char and tar, while the gas phase can be described directly by means of chemical equilibrium. The aforementioned approach gives a set of ordinary, linear, and nonlinear differential equations that are solved numerically with a consistent numerical scheme (i.e., the Totally Implicit Euler method). Chemical equilibrium was solved using CANTERA coupled with a code written in MATLAB. The results showed that the scheme preserved the tar-gas competitive characteristic for cellulose pyrolysis. The gas phase was defined as a mixture of CO₂, CO, H₂O, CH₄, H₂, and N₂, showing a similar composition compared to models from the literature. Finally, the extension of the model to biomass in general is straightforward for including hemicellulose and lignin. The formulation is described in detail throughout the document in order to be replicated and evaluated for other biological components. Full article

(This article belongs to the Special Issue Biomass Conversion Process and Biorefinery)

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30 pages, 7921 KiB

Open AccessArticle

Renewable Fuels from Integrated Power- and Biomass-to-X Processes: A Superstructure Optimization Study

by Philipp Kenkel, Timo Wassermann and Edwin Zondervan

Processes 2022, 10(7), 1298; https://0-doi-org.brum.beds.ac.uk/10.3390/pr10071298 - 30 Jun 2022

Cited by 3 | Viewed by 2553

Abstract

This work presents a superstructure optimization study for the production of renewable fuels with a focus on jet fuel. Power-to-X via the methanol (MTJ) and Fischer–Tropsch (FT) route is combined with Biomass-to-X (BtX) via an algae-based biorefinery to an integrated Power- and Biomass-to-X [...] Read more.

This work presents a superstructure optimization study for the production of renewable fuels with a focus on jet fuel. Power-to-X via the methanol (MTJ) and Fischer–Tropsch (FT) route is combined with Biomass-to-X (BtX) via an algae-based biorefinery to an integrated Power- and Biomass-to-X (PBtX) process. Possible integration by algae remnant utilization for H₂/CO₂ production, wastewater recycling and heat integration is included. Modeling is performed using the novel Open sUperstrucTure moDeling and OptimizatiOn fRamework (OUTDOOR). Novel methods to account for advanced mass balances and uncertain input data are included. Economic optimization proposes a PBtX process. This process combines algae processing with MTJ and depicts a highly mass- and energy integrated plant. It produces fuels at 211 EUR/MWh_LHV (ca. 2530 EUR/t), a cost reduction of 21% to 11.5% compared to stand-alone electricity- or bio-based production at algae costs of 25 EUR/t_Algae-sludge and electricity costs of 72 EUR/MWh. Investigation of uncertain data indicates that a combination of BtX and MTJ is economically superior to FT for a wide parameter range. Only for high algae costs of >40 EUR/t_Algae-sludge stand-alone electricity-based MTJ is economically superior and for high MTJ costs above 2000–2400 EUR/t_Jet FT is the optimal option. Full article

(This article belongs to the Special Issue Biomass Conversion Process and Biorefinery)

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13 pages, 3679 KiB

Open AccessEditor’s ChoiceArticle

High Surface Area–Activated Carbon Production from Cow Manure Controlled by Heat Treatment Conditions

by Jung Eun Park, Gi Bbum Lee, Ho Kim and Bum Ui Hong

Processes 2022, 10(7), 1282; https://0-doi-org.brum.beds.ac.uk/10.3390/pr10071282 - 29 Jun 2022

Cited by 1 | Viewed by 3910

Abstract

In this study, methods of adding value to cow manure were studied. Due to the properties of cow manure, activated carbon with a high surface area can only be produced by increasing the fixed carbon ratio and removing the ash content. Activated carbon [...] Read more.

In this study, methods of adding value to cow manure were studied. Due to the properties of cow manure, activated carbon with a high surface area can only be produced by increasing the fixed carbon ratio and removing the ash content. Activated carbon was fabricated using five different treatments: (1) raw material–chemical activation, (2) raw material–hydrothermal carbonization–chemical activation, (3) raw material–hydrothermal carbonization–chemical activation–acid washing, (4) raw material–hydrothermal carbonization–heat treatment–chemical activation, and (5) raw material–hydrothermal carbonization–chemical activation–acid washing. The products then underwent proximate, elementary, and surface area analyses. In addition, changes in activated carbon properties depending on the heat treatment temperature (300, 500, 700 °C) and the applied chemical activator ratios (1:1–1:3) were examined. The results showed that the best heat treatment temperature was 300 °C, and the cow manure to chemical activator ratio was 1:2. The heat treatment stabilization process increases the fixed carbon ratio and the solid yield, and the acid wash process removes substances that restrain the increase in surface area. Therefore, activated carbon with a surface area of 1955 m²/g can be produced after the addition of heat treatment and an acid wash to the process. In addition, the adsorption properties of activated carbon with different heat treatment conditions were studied. Full article

(This article belongs to the Special Issue Biomass Conversion Process and Biorefinery)

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13 pages, 864 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Valorising Agricultural Residues through Pelletisation

by Daniele Duca, Vittorio Maceratesi, Sara Fabrizi and Giuseppe Toscano

Processes 2022, 10(2), 232; https://0-doi-org.brum.beds.ac.uk/10.3390/pr10020232 - 26 Jan 2022

Cited by 3 | Viewed by 2364

Abstract

The agricultural sector and its related production chains are good sources of residual biomass. Olive and vineyard pruning residues are present in high quantities in Italy. The limited bulk and energy densities of these biomass materials affect the harvesting and logistic costs, limiting [...] Read more.

The agricultural sector and its related production chains are good sources of residual biomass. Olive and vineyard pruning residues are present in high quantities in Italy. The limited bulk and energy densities of these biomass materials affect the harvesting and logistic costs, limiting energy and environmental sustainability. Pelletisation is the most efficient process for increasing bulk and energy densities. This study evaluates the pelletisation process of olive and vineyard prunings, pure, or blended with variable quantities of spruce sawdust. A 15 kW pelletisation system was chosen, in line with production at the farm level. The most important quality parameters of the produced agripellets were analyzed. The results of this investigation suggest that blending could valorize other biomass materials less suitable for pelletisation and reach the pellet quality required by Italian technical standards. The addition of pruning residues to spruce sawdust leads to an improvement in durability. Spruce sawdust pellets have a durability value of 78.4%. Adding 20% of olive prunings (S80O20) increases this value to 92.2, while adding 20% vineyard prunings (S80V20) increases this value up to 90.3. The addition of 20% of pruning residues significantly increased the length and decreased fines. Full article

(This article belongs to the Special Issue Biomass Conversion Process and Biorefinery)

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13 pages, 1487 KiB

Open AccessFeature PaperArticle

Effect of Different Pretreatments on Sludge Solubilization and Estimation of Bioenergy Potential

by Reshma Babu, Gustavo Capannelli and Antonio Comite

Processes 2021, 9(8), 1382; https://0-doi-org.brum.beds.ac.uk/10.3390/pr9081382 - 09 Aug 2021

Cited by 8 | Viewed by 2302

Abstract

Most of the conventional treatments of waste-activated sludge (WAS) are devoted to their minimization and destruction. On the other hand, the biomass contained in WAS can be utilized as a valuable source of renewable carbon. In this study, the influence of different pretreatments [...] Read more.

Most of the conventional treatments of waste-activated sludge (WAS) are devoted to their minimization and destruction. On the other hand, the biomass contained in WAS can be utilized as a valuable source of renewable carbon. In this study, the influence of different pretreatments (ultrasonication, chemical, thermal, and combined pretreatments) was explored for sludge solubilization. Effects of the pretreatments were investigated as a function of the solubilization of total solids (TS), volatile solids (VS), and chemical oxygen demand (COD). Concentrations of soluble carbohydrates and total nitrogen were also measured. The most effective pretreatment to hydrolyze sludge was found to be the combined alkali–thermal (pH 12, 75 °C) pretreatment method, leading to TS and vs. solubilization of 9.6% and 17.2%, respectively. Soluble COD, carbohydrates, total nitrogen, and proteins estimated in the liquid phase were 5235 mg/L, 732 mg/L, 430 mg/L, and 2688 mg/L, respectively. Thus, the alkali–thermal method could be used for efficient valorization of WAS. Moreover, the solid fraction from all pretreated samples was further subjected to thermogravimetric analysis to estimate its potential for bioenergy from its higher heating value (HHV), which was found to be in the range of 10–11.82 MJ/kg. This study can provide better insight into the efficient valorization of liquid and solid phases of sludge after pretreatment. Full article

(This article belongs to the Special Issue Biomass Conversion Process and Biorefinery)

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32 pages, 3134 KiB

Open AccessFeature PaperArticle

Biogas Reforming as a Precursor for Integrated Algae Biorefineries: Simulation and Techno-Economic Analysis

by Philipp Kenkel, Timo Wassermann and Edwin Zondervan

Processes 2021, 9(8), 1348; https://0-doi-org.brum.beds.ac.uk/10.3390/pr9081348 - 30 Jul 2021

Cited by 7 | Viewed by 2627

Abstract

Biogas is a significant by-product produced in algae processing and may be used for many different applications, not only as a renewable energy carrier but also as a chemical intermediate in integrated algae-based biorefineries. In this work, the reforming of biogas to H [...] Read more.

Biogas is a significant by-product produced in algae processing and may be used for many different applications, not only as a renewable energy carrier but also as a chemical intermediate in integrated algae-based biorefineries. In this work, the reforming of biogas to H₂/CO₂ mixtures (referred to as SynFeed) as feed for the direct hydrogenation of CO₂ to methanol is investigated. Two conventional processes, namely steam methane and autothermal reforming, with upstream CO₂ separation from raw biogas are compared to novel concepts of direct biogas bi- and tri-reforming. In addition, downstream CO₂ separation from SynFeed using the commercial Selexol process to produce pure H₂ and CO₂ is considered. The results show that upstream CO₂ separation with subsequent steam methane reforming is the most economic process, costing 142.48 €/t_SynFeed, and taking into consideration the revenue from excess hydrogen. Bi-reforming is the most expensive process, with a cost of 413.44 €/t_SynFeed, due to the high demand of raw biogas input. Overall, SynFeed from biogas is more economical than SynFeed from CO₂ capture and water electrolysis (464 €/t_SynFeed), but is slightly more expensive than using natural gas as an input (107 €/_SynFeed). Carbon capture using Selexol comes with costs of 22.58–27.19 €/

t_{{CO}_{2}}

, where approximately 50% of the costs are derived from the final CO₂ compression. Full article

(This article belongs to the Special Issue Biomass Conversion Process and Biorefinery)

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10 pages, 2209 KiB

Open AccessCommunication

Towards Full Utilization of Biomass Resources: A Case Study on Industrial Hemp Residue and Spent Mushroom Substrate

by Wubliker Dessie, Xiaofang Luo, Jiachen Tang, Wufei Tang, Meifeng Wang, Zuodong Qin and Yimin Tan

Processes 2021, 9(7), 1200; https://0-doi-org.brum.beds.ac.uk/10.3390/pr9071200 - 12 Jul 2021

Cited by 3 | Viewed by 2373

Abstract

This was early-stage, proof-of-concept research on the full utilization of biomass resources. The current study considered industrial hemp residue (IHR) and spent mushroom substrate (SMS) to demonstrate the initial upstream steps towards the total valorization of biomass. Accordingly, different pretreatment methods such as [...] Read more.

This was early-stage, proof-of-concept research on the full utilization of biomass resources. The current study considered industrial hemp residue (IHR) and spent mushroom substrate (SMS) to demonstrate the initial upstream steps towards the total valorization of biomass. Accordingly, different pretreatment methods such as autohydrolysis, thermal hydrolysis, and thermochemical hydrolysis methods were employed against individual and various mix ratios of IHR and SMS. To this end, raw materials, hydrolysates, and residual solids were analyzed to gain some insights, identify gaps, and suggest future research directions in this area. Implementation of the full utilization of biomass resources is, in fact, not only a matter of transforming the resources into valuable products, but it is also a plausible waste management strategy in the quest towards the development of a circular bioeconomy and sustainable future. Full article

(This article belongs to the Special Issue Biomass Conversion Process and Biorefinery)

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Review

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21 pages, 3353 KiB

Open AccessFeature PaperEditor’s ChoiceReview

Advancements in the Conversion of Lipid-Rich Biowastes and Lignocellulosic Residues into High-Quality Road and Jet Biofuels Using Nanomaterials as Catalysts

by Max J. A. Romero, Daniele Duca and Giuseppe Toscano

Processes 2022, 10(2), 187; https://0-doi-org.brum.beds.ac.uk/10.3390/pr10020187 - 18 Jan 2022

Cited by 3 | Viewed by 2653

Abstract

At present, the majority of available road and jet biofuels are produced from oleochemical feedstocks that include vegetable oils and biowastes such as waste cooking oils and animal fats. Additionally, one of the most promising ways to achieve long-term environmental goals is to [...] Read more.

At present, the majority of available road and jet biofuels are produced from oleochemical feedstocks that include vegetable oils and biowastes such as waste cooking oils and animal fats. Additionally, one of the most promising ways to achieve long-term environmental goals is to sustainably use lignocellulosic residues. These resources must be treated through a deoxygenation process and subsequent upgrading processes to obtain high-quality road and jet biofuels. Accordingly, in this review, we explore recent advancements in the deoxygenation of oleochemical and lignocellulosic feedstocks in the absence of hydrogen to produce high-quality road and jet biofuels, mainly focusing on the use of nanomaterials as catalysts and the valorization of lipid-rich biowastes and lignocellulosic residues. As a result, we found that regardless of the catalyst particle size, the coexistence of basic sites and weak/medium acid sites is highly important in catalytic systems. Basic sites can enhance the removal of oxygenates via decarboxylation and decarbonylation reactions and inhibit coke formation, while weak/medium acid sites can enhance the cracking reaction. Additionally, the extraction of value-added derivatives from lignocellulosic residues and their subsequent upgrade require the use of advanced methods such as the lignin-first approach and condensation reactions. Full article

(This article belongs to the Special Issue Biomass Conversion Process and Biorefinery)

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23 pages, 1505 KiB

Open AccessFeature PaperReview

Nanocellulose from Agricultural Wastes: Products and Applications—A Review

by Soledad Mateo, Silvia Peinado, Francisca Morillas-Gutiérrez, M. Dolores La Rubia and Alberto J. Moya

Processes 2021, 9(9), 1594; https://0-doi-org.brum.beds.ac.uk/10.3390/pr9091594 - 06 Sep 2021

Cited by 69 | Viewed by 9871

Abstract

The isolation of nanocellulose from different agricultural residues is becoming an important research field due to its versatile applications. This work collects different production processes, including conditioning steps, pretreatments, bleaching processes and finally purification for the production of nanocellulose in its main types [...] Read more.

The isolation of nanocellulose from different agricultural residues is becoming an important research field due to its versatile applications. This work collects different production processes, including conditioning steps, pretreatments, bleaching processes and finally purification for the production of nanocellulose in its main types of morphologies: cellulose nanofiber (CNF) and cellulose nanocrystal (CNC). This review highlights the importance of agricultural wastes in the production of nanocellulose in order to reduce environmental impact, use of fossil resources, guarantee sustainable economic growth and close the circle of resource use. Finally, the possible applications of the nanocellulose obtained as a new source of raw material in various industrial fields are discussed. Full article

(This article belongs to the Special Issue Biomass Conversion Process and Biorefinery)

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