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Biomass Processing for Biofuels, Bioenergy and Chemicals

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

Deadline for manuscript submissions: closed (31 December 2019) | Viewed by 135463

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Department of Aeronautics and Astronautics, National Cheng Kung University, Tainan 701, Taiwan
Interests: bioenergy; hydrogen energy; clean energy; thermoelectric generation; environmental engineering; AI & machine leaning for energy
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School of Information, Systems, and Modelling, Faculty of Engineering and Information Technology, University of Technology, Sydney, Ultimo, NSW, Australia
Interests: energy and fuel; renewable energy; environmental sustainability; biomass energy; thermal engineering; green technology
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Guest Editor
Material Resource Efficiency Division (MRED), CSIR-IIP, Dehradun, Uttarakhand 248005, India
Interests: biofuels & biochar; valorization of lignin; waste plastics conversion
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Biomass is a renewable and sustainable energy source that develops from organic materials from plants, animals and wastes. Biomass can be used to produce renewable electricity, thermal energy, or transportation fuels (biofuels) and high value functional chemicals. As an energy source, biomass can either be used directly via combustion to produce heat, or indirectly after converting it to various forms of bioenergy and biofuel using thermochemical or biochemical pathways. The conversion of biomass can be processed by various advanced methods, which are broadly classified into thermochemical conversion, biochemical conversion, electrochemical conversion, etc. Advanced development technologies and processes are possible to convert the biomass into alternative energy sources in solid (charcoal, biochar and RDF, etc.), liquid (biodiesel, algae biofuel, bioethanol, pyrolysis and liquefaction bio-oils), and gaseous (biogas, syngas, and biohydrogen, etc.) form. Biomass cannot replace our current dependence on coal, oil, and natural gas, but it can complement other renewables such as solar and wind energy. Thus, due to the merits of biomass energy for environmental sustainability, biofuel and bioenergy technologies play a crucial role in the renewable energy development and replacement of chemicals from highly functional biomass. This Special Issue aims to publish a comprehensive overview and in-depth technical research paper addressing recent progress in biomass conversion processes. Studies of advanced techniques and methods for bioenergy and biofuel production are also welcomed. Research involving experimental and numerical studies, recent developments, and the current state of the art and emerging technologies in this field are highly encouraged.

Prof. Dr. Wei-Hsin Chen
Prof. Dr. Hwai Chyuan Ong
Prof. Dr. Thallada Bhaskar
Guest Editors

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Keywords

  • biomass
  • biofuel
  • bioenergy
  • biorefinery
  • chemicals
  • physical conversion
  • thermochemical conversion
  • chemical conversion
  • biological conversion
  • production optimization
  • process design
  • thermodynamic analysis
  • gasification process

Published Papers (22 papers)

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21 pages, 6641 KiB  
Article
Optimization, Transesterification and Analytical Study of Rhus typhina Non-Edible Seed Oil as Biodiesel Production
by Inam Ullah Khan, Zhenhua Yan and Jun Chen
Energies 2019, 12(22), 4290; https://doi.org/10.3390/en12224290 - 11 Nov 2019
Cited by 12 | Viewed by 2873
Abstract
Production of biodiesel from non-edible oils is one of the effective methods to reduce production costs and alleviate the obstacle of traditional raw material supply. Rhus typhina L. (RT) is a promising non-edible plant because it grows fast and has abundant seeds. [...] Read more.
Production of biodiesel from non-edible oils is one of the effective methods to reduce production costs and alleviate the obstacle of traditional raw material supply. Rhus typhina L. (RT) is a promising non-edible plant because it grows fast and has abundant seeds. But previously reported oil content of RT was only 9.7% and 12%. Further research into improving the biodiesel production of RT seed oil is urgently needed. Here we obtained the biodiesel production of RT with a maximum oil content of 22% with a low free fatty acid content of 1.0%. The fatty acid methyl ester (FAMEs) of the RT seed oil was produced by a standard optimized protocol use KOH as a catalyst with the highest yield of 93.4% (w/w). The quality and purity of RT FAMEs, as well as the physio-chemical characterizations of the biodiesel products, were investigated and compared with the international standard of ASTM D6751 and EN 14214. The values of fuel properties are comparable with mineral diesel and environmentally friendly. Overall, the proposed RT seed oil could be a potential source of raw materials for producing high-quality biodiesel after the optimization and transesterification. Full article
(This article belongs to the Special Issue Biomass Processing for Biofuels, Bioenergy and Chemicals)
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17 pages, 1864 KiB  
Article
Product Characteristics of Torrefied Wood Sawdust in Normal and Vacuum Environments
by Yi-Kai Chih, Wei-Hsin Chen, Hwai Chyuan Ong and Pau Loke Show
Energies 2019, 12(20), 3844; https://doi.org/10.3390/en12203844 - 11 Oct 2019
Cited by 16 | Viewed by 2804
Abstract
To investigate the efficacy of torrefaction in a vacuum environment, wood sawdust was torrefied at various temperatures (200–300 °C) in different atmospheres (nitrogen and vacuum) with different residence times (30 and 60 min). It was found that the amount of biochar reduced at [...] Read more.
To investigate the efficacy of torrefaction in a vacuum environment, wood sawdust was torrefied at various temperatures (200–300 °C) in different atmospheres (nitrogen and vacuum) with different residence times (30 and 60 min). It was found that the amount of biochar reduced at the same rate—regardless of atmosphere type—throughout the torrefaction process. In terms of energy density, the vacuum system produced biochar with better higher heating value (HHV, MJ/kg) than the nitrogen system below 250 °C. This was the case because the moisture and the high volatility compounds such as aldehydes diffused more easily in a vacuum. Over 250 °C, however, a greater amount of low volatility compounds evaded from the vacuum system, resulting in lower higher heating value in the biochar. Despite the mixed results with the solid products, the vacuum system increased the higher heating value of its liquid products more significantly than did the nitrogen system regardless of torrefaction temperature. It was found that 23% of the total energy output came from the liquid products in the vacuum system; the corresponding ratio was 19% in the nitrogen system. With liquid products contributing to a larger share of the total energy output, the vacuum system outperformed the nitrogen system in terms of energy density. Full article
(This article belongs to the Special Issue Biomass Processing for Biofuels, Bioenergy and Chemicals)
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21 pages, 5553 KiB  
Article
Modification of a Direct Injection Diesel Engine in Improving the Ignitability and Emissions of Diesel–Ethanol–Palm Oil Methyl Ester Blends
by Norhidayah Mat Taib, Mohd Radzi Abu Mansor and Wan Mohd Faizal Wan Mahmood
Energies 2019, 12(14), 2644; https://doi.org/10.3390/en12142644 - 10 Jul 2019
Cited by 2 | Viewed by 2702
Abstract
Blending diesel with biofuels, such as ethanol and palm oil methyl ester (PME), enhances the fuel properties and produces improved engine performance and low emissions. However, the presence of ethanol, which has a small cetane number and low heating value, reduces the fuel [...] Read more.
Blending diesel with biofuels, such as ethanol and palm oil methyl ester (PME), enhances the fuel properties and produces improved engine performance and low emissions. However, the presence of ethanol, which has a small cetane number and low heating value, reduces the fuel ignitability. This work aimed to study the effect of injection strategies, compression ratio (CR), and air intake temperature (Ti) modification on blend ignitability, combustion characteristics, and emissions. Moreover, the best composition of diesel–ethanol–PME blends and engine modification was selected. A simulation was also conducted using Converge CFD software based on a single-cylinder direct injection compression ignition Yanmar TF90 engine parameter. Diesel–ethanol–PME blends that consist of 10% ethanol with 40% PME (D50E10B40), D50E25B25, and D50E40B10 were selected and conducted on different injection strategies, compression ratios, and intake temperatures. The results show that shortening the injection duration and increasing the injected mass has no significant effect on ignition. Meanwhile, advancing the injection timing improves the ignitability but with weak ignition energy. Therefore, increasing the compression ratio and ambient temperature helps ignite the non-combustible blends due to the high temperature and pressure. This modification allowed the mixture to ignite with a minimum CR of 20 and Ti of 350 K. Thus, blending high ethanol contents in a diesel engine can be applied by advancing the injection, increasing the CR, and increasing the ambient temperature. From the emission comparison, the most suitable mixtures that can be operated in the engine without modification is D50E25B25, and the most appropriate modification on the engine is by increasing the ambient temperature at 350 K. Full article
(This article belongs to the Special Issue Biomass Processing for Biofuels, Bioenergy and Chemicals)
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15 pages, 3973 KiB  
Article
Application of Biochar Derived from Different Types of Biomass and Treatment Methods as a Fuel Source for Direct Carbon Fuel Cells
by Lithnes Kalaivani Palniandy, Li Wan Yoon, Wai Yin Wong, Siek-Ting Yong and Ming Meng Pang
Energies 2019, 12(13), 2477; https://doi.org/10.3390/en12132477 - 27 Jun 2019
Cited by 33 | Viewed by 4049
Abstract
The direct carbon fuel cell (DCFC) is an emerging technology for energy production. The application of biomass in DCFCs will be a major transition from the use of coal to generate energy. However, the relationship between biomass or biochar composition and the electrochemical [...] Read more.
The direct carbon fuel cell (DCFC) is an emerging technology for energy production. The application of biomass in DCFCs will be a major transition from the use of coal to generate energy. However, the relationship between biomass or biochar composition and the electrochemical performance of a DCFC is yet to be studied. The performance of a DCFC using fuel sources derived from woody and non-woody biomass were compared in this study. The effect of pyrolysis temperature ranges from 550 °C to 850 °C on the preparation of biochar from rubber wood (RW) and rice husk (RH) were evaluated for power generation from DCFCs. In addition, the effect of applying chemical pre-treatment and post-treatment on biochar were further investigated for DCFC performance. In general, the power density derived from rubber wood biochar is significantly higher (2.21 mW cm−2) compared to rice husk biochar (0.07 mW cm−2). This might be due to the presence of an oxygen functional group, higher fixed carbon content, and lower ash content in rubber wood biochar. The acid and alkaline pre-treatment and post-treatment have altered the composition with a lower ash content in rubber wood biochar. The structural and compositional alterations in alkaline pre-treatment bring a positive effect in enhancing the power density from DCFCs. This study concludes that woody biochar is more suitable for DCFC application, and alkaline pre-treatment in the preparation of biochar enhances the electrochemical activity of DCFC. Further investigation on the optimization of DCFC operating conditions could be performed. Full article
(This article belongs to the Special Issue Biomass Processing for Biofuels, Bioenergy and Chemicals)
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16 pages, 1504 KiB  
Article
Investigation of Temperature Effect on Start-Up Operation from Anaerobic Digestion of Acidified Palm Oil Mill Effluent
by Muhammad Arif Fikri Hamzah, Jamaliah Md Jahim, Peer Mohamed Abdul and Ahmad Jaril Asis
Energies 2019, 12(13), 2473; https://doi.org/10.3390/en12132473 - 27 Jun 2019
Cited by 19 | Viewed by 3387
Abstract
Malaysia is one of the largest palm oil producers worldwide and its most abundant waste, palm oil mill effluent (POME), can be used as a feedstock to produce methane. Anaerobic digestion is ideal for treating POME in methane production due to its tolerance [...] Read more.
Malaysia is one of the largest palm oil producers worldwide and its most abundant waste, palm oil mill effluent (POME), can be used as a feedstock to produce methane. Anaerobic digestion is ideal for treating POME in methane production due to its tolerance to high-strength chemical oxygen demand (COD). In this work, we compared the culture conditions during the start-up of anaerobic digestion of acidified POME between thermophilic (55 °C) and mesophilic (37 °C) temperatures. The pH of the digester was maintained throughout the experiment at 7.30 ± 0.2 in a working volume of 1000 mL. This study revealed that the thermophilic temperature stabilized faster on the 44th day compared to the 52nd day for the mesophilic temperature. Furthermore, the thermophilic temperature indicated higher biogas production at 0.60 L- CH 4 /L·d compared to the mesophilic temperature at 0.26 L- CH 4 /L·d. Results from this study were consistent with the COD removal of thermophilic temperature which was also higher than the mesophilic temperature. Full article
(This article belongs to the Special Issue Biomass Processing for Biofuels, Bioenergy and Chemicals)
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16 pages, 1909 KiB  
Article
Biogas Potential from the Anaerobic Digestion of Potato Peels: Process Performance and Kinetics Evaluation
by Spyridon Achinas, Yu Li, Vasileios Achinas and Gerrit Jan Willem Euverink
Energies 2019, 12(12), 2311; https://doi.org/10.3390/en12122311 - 17 Jun 2019
Cited by 53 | Viewed by 6155
Abstract
This article intends to promote the usage of potato peels as efficient substrate for the anaerobic digestion process for energy recovery and waste abatement. This study examined the performance of anaerobic digestion of potato peels in different inoculum-to-substrate ratios. In addition, the impact [...] Read more.
This article intends to promote the usage of potato peels as efficient substrate for the anaerobic digestion process for energy recovery and waste abatement. This study examined the performance of anaerobic digestion of potato peels in different inoculum-to-substrate ratios. In addition, the impact of combined treatment with cow manure and pretreatment of potato peels was examined. It was found that co-digestion of potato peel waste and cow manure yielded up to 237.4 mL CH4/g VSadded, whereas the maximum methane yield from the mono-digestion of potato peels was 217.8 mL CH4/g VSadded. Comparing the co-digestion to mono-digestion of potato peels, co-digestion in PPW/CM ratio of 60:40 increased the methane yield by 10%. In addition, grinding and acid hydrolysis applied to potato peels were positively effective in increasing the methane amount reaching 260.3 and 283.4 mL CH4/g VSadded respectively. Likewise, compared to untreated potato peels, pretreatment led to an elevation of the methane amount by 9% and 17% respectively and alleviated the kinetics of biogas production. Full article
(This article belongs to the Special Issue Biomass Processing for Biofuels, Bioenergy and Chemicals)
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13 pages, 3530 KiB  
Article
Safflower Biodiesel: Improvement of its Oxidative Stability by Using BHA and TBHQ
by Sergio Nogales-Delgado, José María Encinar and Juan Félix González
Energies 2019, 12(10), 1940; https://doi.org/10.3390/en12101940 - 21 May 2019
Cited by 54 | Viewed by 4049
Abstract
Biodiesel is gaining more and more importance due to environmental issues. This way, alternative and sustainable crops as new biofuel sources are demanded. Safflower could be a sustainable raw material for biodiesel production, showing one disadvantage (as many biodiesels from vegetable oils), that [...] Read more.
Biodiesel is gaining more and more importance due to environmental issues. This way, alternative and sustainable crops as new biofuel sources are demanded. Safflower could be a sustainable raw material for biodiesel production, showing one disadvantage (as many biodiesels from vegetable oils), that is, a short oxidative stability. Consequently, the use of antioxidants to increase this parameter is mandatory. The aim of this research work was to assess the effect of two antioxidants (butylated hydroxyanisole, BHA, and tert-butylhydroquinone, TBHQ) on the oxidative stability of safflower biodiesel, which was characterized paying attention to its fatty acid methyl ester profile. For oxidative stability, the Rancimat method was used, whereas for fatty acid profile gas chromatography was selected. For the remaining parameters, the methods were followed according to the UNE-EN 14214 standard. The overall conclusion was that safflower biodiesel could comply with the standard, thanks to the use of antioxidants, with TBHQ being more effective than BHA. On the other hand, the combined use of these antioxidants did not show, especially at low concentrations, a synergic or additive effect, which makes the mixture of these antioxidants unsuitable to improve the oxidative stability. Full article
(This article belongs to the Special Issue Biomass Processing for Biofuels, Bioenergy and Chemicals)
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15 pages, 1794 KiB  
Article
Potential Protein and Biodiesel Sources from Black Soldier Fly Larvae: Insights of Larval Harvesting Instar and Fermented Feeding Medium
by Chung-Yiin Wong, Siti-Suhailah Rosli, Yoshimitsu Uemura, Yeek Chia Ho, Arunsri Leejeerajumnean, Worapon Kiatkittipong, Chin-Kui Cheng, Man-Kee Lam and Jun-Wei Lim
Energies 2019, 12(8), 1570; https://doi.org/10.3390/en12081570 - 25 Apr 2019
Cited by 69 | Viewed by 9258
Abstract
Primarily produced via transesterification of lipid sources, fatty acid methyl ester (FAME) of biodiesel derived from insect larvae has gained momentum in a great deal of research done over other types of feedstock. From the self-harvesting nature of black soldier fly larvae (BSFL), [...] Read more.
Primarily produced via transesterification of lipid sources, fatty acid methyl ester (FAME) of biodiesel derived from insect larvae has gained momentum in a great deal of research done over other types of feedstock. From the self-harvesting nature of black soldier fly larvae (BSFL), research had, however, only concentrated on the harvest of BSFL on sixth instar. Through rearing BSFL on coconut endosperm waste (CEW), 100 BSFL were harvested at the fifth and sixth instar, then modification on CEW with mixed-bacteria powder was carried out. It was found that the fifth instar BSFL had 34% lipid content, which was 8% more than the sixth instar. Both instars had similar corrected protein contents around 35–38%. The sixth instar BSFL contained around 19% of chitin, which was about 11% more than the fifth instar. Biodiesel products from both instars showed no differences in terms of FAME content. With modification on CEW, at 0.5 wt% of mixed-bacteria powder concentration, the maximum waste-to-biomass conversion (WBC) and protein conversion (PC) were achieved at 9% and 60%, respectively. Moreover, even with the shorter fermentation time frame of CEW, it did not affect the development of BSFL in terms of its WBC and PC when fed with 14 and 21 days fermented medium. FAME from all groups set, which predominantly constituted about C12:0 at around 60%, followed by C14:0 at around 15%, C16:0, and C18:1 both at 10% on average. Lastly, the FAME yield from BSFL was improved from 25% (sixth instar) to 33% (fifth instar) and showed its highest at 38.5% with modification on raw CEW with 0.5 wt% mixed-bacteria powder and fermented for 21 days. Thus, harvesting BSFL at earlier instar is more beneficial and practical, as it improves the FAME yield from the BSFL biomass. Full article
(This article belongs to the Special Issue Biomass Processing for Biofuels, Bioenergy and Chemicals)
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20 pages, 3125 KiB  
Article
A Novel Process for Production of Calophyllum Inophyllum Biodiesel with Electromagnetic Induction
by Sri Kurniati, Sudjito Soeparman, Sudarminto Setyo Yuwono, Lukman Hakim and Sudirman Syam
Energies 2019, 12(3), 383; https://doi.org/10.3390/en12030383 - 25 Jan 2019
Cited by 11 | Viewed by 4618
Abstract
A novel method as proposed in the production of Calophyllum inophyllum biodiesel has been investigated experimentally. This study reports the results of biodiesel processing with electromagnetic induction technology. The applied method is aimed to compare the results of Calophyllum inophyllum biodiesel processing among [...] Read more.
A novel method as proposed in the production of Calophyllum inophyllum biodiesel has been investigated experimentally. This study reports the results of biodiesel processing with electromagnetic induction technology. The applied method is aimed to compare the results of Calophyllum inophyllum biodiesel processing among conventional, microwave and electromagnetic induction. The degumming, transesterification, and esterification process of the 3 methods are measured by stopwatch to obtain time comparison data. Characteristics of viscosity, density, and fatty acid metil ester (FAME) are obtained from testing of a Gas Chromatography-mass Spectrometry (GCMS) at the Integrated Research and Testing Laboratory, Gadjah Mada University, Yogyakarta. The results present that the biodiesel produced by this method satisfies the biodiesel standards and their characteristics are better than the biodiesel produced by conventional and microwave methods. The electromagnetic induction method also offers a fast and easy route to produce biodiesel with the advantage of increasing the reaction rate and improving the separation process compared to other methods. This advanced technology has the potential to significantly increase biodiesel production with considerable potential to reduce production time and costs. Full article
(This article belongs to the Special Issue Biomass Processing for Biofuels, Bioenergy and Chemicals)
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13 pages, 3562 KiB  
Article
Optimization of Biodiesel Production Using Nanomagnetic CaO-Based Catalysts with Subcritical Methanol Transesterification of Rubber Seed Oil
by Veronica Winoto and Nuttawan Yoswathana
Energies 2019, 12(2), 230; https://doi.org/10.3390/en12020230 - 12 Jan 2019
Cited by 20 | Viewed by 4671
Abstract
The molar ratio of methanol to rubber seed oil (RSO), catalyst loading, and the reaction time of RSO biodiesel production were optimized in this work. The response surface methodology, using the Box–Behnken design, was analyzed to determine the optimum fatty acid methyl ester [...] Read more.
The molar ratio of methanol to rubber seed oil (RSO), catalyst loading, and the reaction time of RSO biodiesel production were optimized in this work. The response surface methodology, using the Box–Behnken design, was analyzed to determine the optimum fatty acid methyl ester (FAME) yield. The performance of various nanomagnetic CaO-based catalysts—KF/CaO-Fe3O4, KF/CaO-Fe3O4-Li (Li additives), and KF/CaO-Fe3O4-Al (Al additives)—were compared. Rubber seed biodiesel was produced via the transesterification process under subcritical methanol conditions with nanomagnetic catalysts. The experimental results indicated that the KF/CaO-Fe3O4-Al nanomagnetic catalyst produced the highest FAME yield of 86.79%. The optimum conditions were a 28:1 molar ratio of methanol to RSO, 1.5 wt % catalyst, and 49 min reaction time. Al additives of KF/CaO-Fe3O4 nanomagnetic catalyst enhanced FAME yield without Al up to 18.17% and shortened the reaction time by up to 11 min. Full article
(This article belongs to the Special Issue Biomass Processing for Biofuels, Bioenergy and Chemicals)
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21 pages, 3777 KiB  
Article
Fatty Acids, Hydrocarbons and Terpenes of Nannochloropsis and Nannochloris Isolates with Potential for Biofuel Production
by Alan Rodrigo López-Rosales, Katia Ancona-Canché, Juan Carlos Chavarria-Hernandez, Felipe Barahona-Pérez, Tanit Toledano-Thompson, Gloria Garduño-Solórzano, Silvia López-Adrian, Blondy Canto-Canché, Erik Polanco-Lugo and Ruby Valdez-Ojeda
Energies 2019, 12(1), 130; https://doi.org/10.3390/en12010130 - 31 Dec 2018
Cited by 19 | Viewed by 4805
Abstract
Marine microalgae are a promising feedstock for biofuel production given their high growth rates and biomass production together with cost reductions due to the use of seawater for culture preparation. However, different microalgae species produce different families of compounds. Some compounds could be [...] Read more.
Marine microalgae are a promising feedstock for biofuel production given their high growth rates and biomass production together with cost reductions due to the use of seawater for culture preparation. However, different microalgae species produce different families of compounds. Some compounds could be used directly as fuels, while others require thermochemical processing to obtain quality biofuels. This work focuses on the characterization of three marine microalgae strains native in Mexico and reported for the first time. Ultrastructure and phylogenetic analysis, suggested that they belong to Nannochloropsis sp. (NSRE-1 and NSRE-2) and Nannochloris sp. (NRRE-1). The composition of their lipid fractions included hydrocarbons, triacylglycerides (TAGs), free fatty acids (FFAs) and terpenes. Based on theoretical estimations from TAG and FFA composition, the potential biodiesels were found to comply with six of the seven estimated properties (ASTM D6751 and EN 14214). On the other hand, hydrocarbons and terpenes synthesized by the strains have outstanding potential as precursors for the production of other renewable fuels, mainly green diesel and bio-jet fuel, which are “drop-in” fuels with quality properties similar to fossil fuels. The validity of this theoretical analysis was demonstrated for the oxygenates of strain NSRE-2, which were experimentally hydrodeoxygenated, obtaining a high-quality renewable diesel as the reaction product. Full article
(This article belongs to the Special Issue Biomass Processing for Biofuels, Bioenergy and Chemicals)
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12 pages, 440 KiB  
Article
Hydrogen Production from Coffee Mucilage in Dark Fermentation with Organic Wastes
by Edilson León Moreno Cárdenas, Arley David Zapata-Zapata and Daehwan Kim
Energies 2019, 12(1), 71; https://doi.org/10.3390/en12010071 - 27 Dec 2018
Cited by 16 | Viewed by 4289
Abstract
One of primary issues in the coffee manufacturing industry is the production of large amounts of undesirable residues, which include the pericarp (outer skin), pulp (outer mesocarp), parchment (endocarp), silver-skin (epidermis) and mucilage (inner mesocarp) that cause environmental problems due to toxic molecules [...] Read more.
One of primary issues in the coffee manufacturing industry is the production of large amounts of undesirable residues, which include the pericarp (outer skin), pulp (outer mesocarp), parchment (endocarp), silver-skin (epidermis) and mucilage (inner mesocarp) that cause environmental problems due to toxic molecules contained therein. This study evaluated the optimal hydrogen production from coffee mucilage combined with organic wastes (wholesale market garbage) in a dark fermentation process. The supplementation of organic wastes offered appropriate carbon and nitrogen sources with further nutrients; it was positively effective in achieving cumulative hydrogen production. Three different ratios of coffee mucilage and organic wastes (8:2, 5:5, and 2:8) were tested in 30 L bioreactors using two-level factorial design experiments. The highest cumulative hydrogen volume of 25.9 L was gained for an 8:2 ratio (coffee mucilage: organic wastes) after 72 h, which corresponded to 1.295 L hydrogen/L substrates (0.248 mol hydrogen/mol hexose). Biochemical identification of microorganisms found that seven microorganisms were involved in the hydrogen metabolism. Further studies of anaerobic fermentative digestion with each isolated pure bacterium under similar experimental conditions reached a lower final hydrogen yield (up to 9.3 L) than the result from the non-isolated sample (25.9 L). Interestingly, however, co-cultivation of two identified microorganisms (Kocuria kristinae and Brevibacillus laterosporus), who were relatively highly associated with hydrogen production, gave a higher yield (14.7 L) than single bacterium inoculum but lower than that of the non-isolated tests. This work confirms that the re-utilization of coffee mucilage combined with organic wastes is practical for hydrogen fermentation in anaerobic conditions, and it would be influenced by the bacterial consortium involved. Full article
(This article belongs to the Special Issue Biomass Processing for Biofuels, Bioenergy and Chemicals)
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11 pages, 1877 KiB  
Article
Effect of Accelerated High Temperature on Oxidation and Polymerization of Biodiesel from Vegetable Oils
by Jae-Kon Kim, Cheol-Hwan Jeon, Hyung Won Lee, Young-Kwon Park, Kyong-il Min, In-ha Hwang and Young-Min Kim
Energies 2018, 11(12), 3514; https://doi.org/10.3390/en11123514 - 17 Dec 2018
Cited by 15 | Viewed by 4689
Abstract
Oxidation of biodiesel (BD) obtained from the decomposition of biomass can damage the fuel injection and engine parts during its use as a fuel. The excess heating of vegetable oils can also cause polymerization of the biodiesel. The extent of BD oxidation depends [...] Read more.
Oxidation of biodiesel (BD) obtained from the decomposition of biomass can damage the fuel injection and engine parts during its use as a fuel. The excess heating of vegetable oils can also cause polymerization of the biodiesel. The extent of BD oxidation depends on its fatty acid composition. In this study, an accelerated oxidation test of BDs at 95 °C was investigated according to ASTM D 2274 by applying a long-term storage test for 16 weeks. The density, viscosity, and total acid number (TAN) of BDs increased because of the accelerated oxidation. Furthermore, the contents of unsaturated fatty acid methyl esters (FAMEs), C18:2 ME, and C18:3 ME in BDs decreased due to the accelerated oxidation. The 1H-nuclear magnetic resonance spectrum of BDs that were obtained from the accelerated high temperature oxidation at 180 °C for 72 h differed from that of fresh BDs. The mass spectrum obtained from the analysis of the model FAME, linoleic acid (C18:2) methyl ester, which was oxidized at high temperature, indicated the formation of dimers and epoxy dimers of linoleic acid (C18:2) methyl ester by a Diels-Alder reaction. Full article
(This article belongs to the Special Issue Biomass Processing for Biofuels, Bioenergy and Chemicals)
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25 pages, 4932 KiB  
Article
A Study of Sewage Sludge Co-Combustion with Australian Black Coal and Shiitake Substrate
by Guan-Bang Chen, Samuel Chatelier, Hsien-Tsung Lin, Fang-Hsien Wu and Ta-Hui Lin
Energies 2018, 11(12), 3436; https://doi.org/10.3390/en11123436 - 7 Dec 2018
Cited by 28 | Viewed by 3682
Abstract
Co-combustion technology can be a gateway to sewage sludge valorization and net CO2 reduction. In this study, combustion characteristics of sewage sludge, Australian black coal, shiitake substrate, and their blends were analyzed via thermogravimetric analysis (TGA) coupled with Fourier transform infrared spectroscopy. [...] Read more.
Co-combustion technology can be a gateway to sewage sludge valorization and net CO2 reduction. In this study, combustion characteristics of sewage sludge, Australian black coal, shiitake substrate, and their blends were analyzed via thermogravimetric analysis (TGA) coupled with Fourier transform infrared spectroscopy. The ignition temperature, burnout temperature, flammability index (C), and combustion characteristics index (S) of the fuels and their respective blends were estimated. Kinetic parameters were also estimated using the Coats-Redfern method. The results showed that the oxidation of the blends had two distinct stages. Synergistic effects existed for all the blends, with negative ones occurring at temperatures between 300 and 500 °C and positive ones during the char oxidation period. In the first oxidation stage, both C and S indexes increased with sludge addition to the coal. However, they decreased with sludge addition in the final oxidation stage. The catalytic effect of the sludge and the shiitake was pronounced in the final oxidation stage and it resulted in a decrease of activation energy. As for the pollutant emissions, the results showed that NOx and SO2 emissions decreased for 25 wt.% sludge addition to the coal. For the sludge-shiitake blends, NOx and SO2 emissions decreased with increasing shiitake addition. The single-pellet combustion results showed that ignition delay time reduced with increasing sludge/coal ratio but increased with increasing sludge/shiitake ratio. The volatile combustion duration decreased with the addition of sludge and total combustion time decreased sharply with increasing sludge ratio. Full article
(This article belongs to the Special Issue Biomass Processing for Biofuels, Bioenergy and Chemicals)
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15 pages, 931 KiB  
Article
Study of the Application of Alkaline Extrusion to the Pretreatment of Eucalyptus Biomass as First Step in a Bioethanol Production Process
by Aleta Duque, Paloma Manzanares, Alberto González and Mercedes Ballesteros
Energies 2018, 11(11), 2961; https://doi.org/10.3390/en11112961 - 31 Oct 2018
Cited by 19 | Viewed by 3914
Abstract
Eucalyptus biomass was studied as a feedstock for sugars release using an alkaline extrusion plus a neutralization-based pretreatment. This approach would be a first step in a bioconversion process aimed at obtaining fuel bioethanol from eucalyptus biomass. The best operation conditions of extrusion [...] Read more.
Eucalyptus biomass was studied as a feedstock for sugars release using an alkaline extrusion plus a neutralization-based pretreatment. This approach would be a first step in a bioconversion process aimed at obtaining fuel bioethanol from eucalyptus biomass. The best operation conditions of extrusion (screw speed, temperature, liquid to solid ratio and NaOH amount) that lead to an effective destructuration of lignocellulose and enhanced sugar release were investigated. Two process configurations, with and without filtration inside the extruder, were tested. In the case without filtration, washed and not washed extrudates were compared. It was demonstrated that filtration step was convenient to remove inorganic salts resulting from neutralization and to promote the mechanical effect of extrusion, but limitations in the machine used in the work prevented testing of temperatures above 100 °C using this configuration. In the no filtration strategy, a temperature of 150 °C allowed attaining the highest glucan and xylan conversion rates by enzymatic hydrolysis of extruded biomass, almost 40% and 75%, respectively, of the maximum yield that could be attained if all carbohydrates contained in raw eucalyptus were converted to sugars. Some of the mechanisms and individual effects underlying alkaline extrusion of eucalyptus were figured out in this work, providing guidelines for a successful pretreatment design that needs to be further studied. Full article
(This article belongs to the Special Issue Biomass Processing for Biofuels, Bioenergy and Chemicals)
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Review

Jump to: Research

23 pages, 2405 KiB  
Review
Organic Carbonate Production Utilizing Crude Glycerol Derived as By-Product of Biodiesel Production: A Review
by Saifuddin Nomanbhay, Mei Yin Ong, Kit Wayne Chew, Pau-Loke Show, Man Kee Lam and Wei-Hsin Chen
Energies 2020, 13(6), 1483; https://doi.org/10.3390/en13061483 - 21 Mar 2020
Cited by 57 | Viewed by 6164
Abstract
As a promising alternative renewable liquid fuel, biodiesel production has increased and eventually led to an increase in the production of its by-product, crude glycerol. The vast generation of glycerol has surpassed the market demand. Hence, the crude glycerol produced should be utilized [...] Read more.
As a promising alternative renewable liquid fuel, biodiesel production has increased and eventually led to an increase in the production of its by-product, crude glycerol. The vast generation of glycerol has surpassed the market demand. Hence, the crude glycerol produced should be utilized effectively to increase the viability of biodiesel production. One of them is through crude glycerol upgrading, which is not economical. A good deal of attention has been dedicated to research for alternative material and chemicals derived from sustainable biomass resources. It will be more valuable if the crude glycerol is converted into glycerol derivatives, and so, increase the economic possibility of the biodiesel production. Studies showed that glycerol carbonate plays an important role, as a building block, in synthesizing the glycerol oligomers at milder conditions under microwave irradiation. This review presents a brief outline of the physio-chemical, thermodynamic, toxicological, production methods, reactivity, and application of organic carbonates derived from glycerol with a major focus on glycerol carbonate and dimethyl carbonate (DMC), as a green chemical, for application in the chemical and biotechnical field. Research gaps and further improvements have also been discussed. Full article
(This article belongs to the Special Issue Biomass Processing for Biofuels, Bioenergy and Chemicals)
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19 pages, 1602 KiB  
Review
Nanomaterials Utilization in Biomass for Biofuel and Bioenergy Production
by Kuan Shiong Khoo, Wen Yi Chia, Doris Ying Ying Tang, Pau Loke Show, Kit Wayne Chew and Wei-Hsin Chen
Energies 2020, 13(4), 892; https://doi.org/10.3390/en13040892 - 17 Feb 2020
Cited by 97 | Viewed by 8092
Abstract
The world energy production trumped by the exhaustive utilization of fossil fuels has highlighted the importance of searching for an alternative energy source that exhibits great potential. Ongoing efforts are being implemented to resolve the challenges regarding the preliminary processes before conversion to [...] Read more.
The world energy production trumped by the exhaustive utilization of fossil fuels has highlighted the importance of searching for an alternative energy source that exhibits great potential. Ongoing efforts are being implemented to resolve the challenges regarding the preliminary processes before conversion to bioenergy such as pretreatment, enzymatic hydrolysis and cultivation of biomass. Nanotechnology has the ability to overcome the challenges associated with these biomass sources through their distinctive active sites for various reactions and processes. In this review, the potential of nanotechnology incorporated into these biomasses as an aid or addictive to enhance the efficiency of bioenergy generation has been reviewed. The fundamentals of nanomaterials along with their various bioenergy applications were discussed in-depth. Moreover, the optimization and enhancement of bioenergy production from lignocellulose, microalgae and wastewater using nanomaterials are comprehensively evaluated. The distinctive features of these nanomaterials contributing to better performance of biofuels, biodiesel, enzymes and microbial fuel cells are also critically reviewed. Subsequently, future trends and research needs are highlighted based on the current literature. Full article
(This article belongs to the Special Issue Biomass Processing for Biofuels, Bioenergy and Chemicals)
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22 pages, 1354 KiB  
Review
Factors Affecting the Performance of Membrane Osmotic Processes for Bioenergy Development
by Wen Yi Chia, Kuan Shiong Khoo, Shir Reen Chia, Kit Wayne Chew, Guo Yong Yew, Yeek-Chia Ho, Pau Loke Show and Wei-Hsin Chen
Energies 2020, 13(2), 481; https://doi.org/10.3390/en13020481 - 19 Jan 2020
Cited by 9 | Viewed by 7983
Abstract
Forward osmosis (FO) and pressure-retarded osmosis (PRO) have gained attention recently as potential processes to solve water and energy scarcity problems with advantages over pressure-driven membrane processes. These processes can be designed to produce bioenergy and clean water at the same time (i.e., [...] Read more.
Forward osmosis (FO) and pressure-retarded osmosis (PRO) have gained attention recently as potential processes to solve water and energy scarcity problems with advantages over pressure-driven membrane processes. These processes can be designed to produce bioenergy and clean water at the same time (i.e., wastewater treatment with power generation). Despite having significant technological advancement, these bioenergy processes are yet to be implemented in full scale and commercialized due to its relatively low performance. Hence, massive and extensive research has been carried out to evaluate the variables in FO and PRO processes such as osmotic membrane, feed solutions, draw solutions, and operating conditions in order to maximize the outcomes, which include water flux and power density. However, these research findings have not been summarized and properly reviewed. The key parts of this review are to discuss the factors influencing the performance of FO and PRO with respective resulting effects and to determine the research gaps in their optimization with the aim of further improving these bioenergy processes and commercializing them in various industrial applications. Full article
(This article belongs to the Special Issue Biomass Processing for Biofuels, Bioenergy and Chemicals)
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21 pages, 2719 KiB  
Review
Potential of Rice Industry Biomass as a Renewable Energy Source
by M. Mofijur, T.M.I. Mahlia, J. Logeswaran, M. Anwar, A.S. Silitonga, S.M. Ashrafur Rahman and A.H. Shamsuddin
Energies 2019, 12(21), 4116; https://doi.org/10.3390/en12214116 - 28 Oct 2019
Cited by 43 | Viewed by 11655
Abstract
Fossil fuel depletion, along with its ever-increasing price and detrimental impact on the environment, has urged researchers to look for alternative renewable energy. Of all the options available, biomass presents a very reliable source due to its never-ending supply. As research on various [...] Read more.
Fossil fuel depletion, along with its ever-increasing price and detrimental impact on the environment, has urged researchers to look for alternative renewable energy. Of all the options available, biomass presents a very reliable source due to its never-ending supply. As research on various biomasses has grown in recent years, waste from these biomasses has also increased, and it is now time to shift the focus to utilizing these wastes for energy. The current waste management system mainly focuses on open burning and soil incorporation as it is cost-effective; however, these affect the environment. There must be an alternative way, such as to use it for power generation. Rice straw and rice husk are examples of such potential biomass waste. Rice is the main food source for the world, mostly in Asian regions, as most people consume rice daily. This paper reviews factors that impact the implementation of rice-straw-based power plants. Ash content and moisture content are important properties that govern combustion, and these vary with location. Logistical improvements are required to reduce the transport cost of rice husk and rice straw, which is higher than the transportation cost of coal. Full article
(This article belongs to the Special Issue Biomass Processing for Biofuels, Bioenergy and Chemicals)
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12 pages, 1040 KiB  
Review
The Potential of Renewable Energy in Timor-Leste: An Assessment for Biomass
by Lelis Gonzaga Fraga, José Carlos F. Teixeira and Manuel Eduardo C. Ferreira
Energies 2019, 12(8), 1441; https://doi.org/10.3390/en12081441 - 15 Apr 2019
Cited by 11 | Viewed by 5705
Abstract
This paper assesses the potential of biomass energy resources in Timor-Leste (TL). Although other renewable energy sources are mentioned in this article, such as wind energy, solar energy, hydropower, bioenergy, including bioethanol and biogas, the main goal is to gather the data on [...] Read more.
This paper assesses the potential of biomass energy resources in Timor-Leste (TL). Although other renewable energy sources are mentioned in this article, such as wind energy, solar energy, hydropower, bioenergy, including bioethanol and biogas, the main goal is to gather the data on biomass in TL and provide such data as useful information for a wide range of end-users. The current evaluation is based on various sources which include previous assessments on biomass and other renewable sources. The energy potential of biomass in TL apart that resulting from vegetation or flora and animals is also derived from agricultural waste, such as waste from rice, corn, and coffee. The analyses also include the contribution of agricultural waste, animal waste, and that from urban waste. The results from this article show that the potential of usable biomass energy in TL from forestry and agriculture is 1.68 × 106 toe/year, animal waste is 4.81 × 103 toe/year, and urban solid waste amounts to 9.55 × 103 toe/year. In addition, it is concluded that biomass alone can fully replace fossil fuels for electricity generation. Full article
(This article belongs to the Special Issue Biomass Processing for Biofuels, Bioenergy and Chemicals)
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27 pages, 7629 KiB  
Review
A Review of Gasoline Compression Ignition: A Promising Technology Potentially Fueled with Mixtures of Gasoline and Biodiesel to Meet Future Engine Efficiency and Emission Targets
by Yanuandri Putrasari and Ocktaeck Lim
Energies 2019, 12(2), 238; https://doi.org/10.3390/en12020238 - 14 Jan 2019
Cited by 15 | Viewed by 5484
Abstract
Efforts have been made to develop efficient and alternative powertrains for internal combustion engines including combustion at low-temperature (LTC) concepts. LTC has been widely studied as a novel combustion mode that offers the possibility to minimize both nitrogen oxide (NOx) and particulate matter [...] Read more.
Efforts have been made to develop efficient and alternative powertrains for internal combustion engines including combustion at low-temperature (LTC) concepts. LTC has been widely studied as a novel combustion mode that offers the possibility to minimize both nitrogen oxide (NOx) and particulate matter (PM) via enhanced air-fuel mixing and intake charge dilution, resulting in lower peak combustion temperatures. Gasoline compression ignition (GCI) is a new ignition method related to the extensive classification of combustion at low-temperature approaches. In this method of ignition, a fuel with high evaporation characteristics and low autoignition sensitivity, for instance gasoline, is burned in a high pressure process. Despite many research efforts, there are still many challenges related with GCI performance for compression ignition (CI) engines. Unstable combustion for idle- to low-load operation was observed because of the low reactivity characteristics of gasoline, and this will affect the efficiency and emissions of the engine. This paper contributes a detailed review of several topics associated with GCI engines and the effort to improve its efficiency and emissions, including its potential when using gasoline-biodiesel blends. Some recommendations are proposed to encourage GCI engines improvement and development in the near future. Full article
(This article belongs to the Special Issue Biomass Processing for Biofuels, Bioenergy and Chemicals)
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24 pages, 3564 KiB  
Review
An Overview of Recent Developments in Biomass Pyrolysis Technologies
by M. N. Uddin, Kuaanan Techato, Juntakan Taweekun, Md Mofijur Rahman, M. G. Rasul, T. M. I. Mahlia and S. M. Ashrafur
Energies 2018, 11(11), 3115; https://doi.org/10.3390/en11113115 - 10 Nov 2018
Cited by 209 | Viewed by 21697
Abstract
Biomass is a promising sustainable and renewable energy source, due to its high diversity of sources, and as it is profusely obtainable everywhere in the world. It is the third most important fuel source used to generate electricity and for thermal applications, as [...] Read more.
Biomass is a promising sustainable and renewable energy source, due to its high diversity of sources, and as it is profusely obtainable everywhere in the world. It is the third most important fuel source used to generate electricity and for thermal applications, as 50% of the global population depends on biomass. The increase in availability and technological developments of recent years allow the use of biomass as a renewable energy source with low levels of emissions and environmental impacts. Biomass energy can be in the forms of biogas, bio-liquid, and bio-solid fuels. It can be used to replace fossil fuels in the power and transportation sectors. This paper critically reviews the facts and prospects of biomass, the pyrolysis process to obtain bio-oil, the impact of different pyrolysis technology (for example, temperature and speed of pyrolysis process), and the impact of various reactors. The paper also discusses different pyrolysis products, their yields, and factors affecting biomass products, including the present status of the pyrolysis process and future challenges. This study concluded that the characteristics of pyrolysis products depend on the biomass used, and what the pyrolysis product, such as bio-oil, can contribute to the local economy. Finally, more research, along with government subsidies and technology transfer, is needed to tackle the future challenges of the development of pyrolysis technology. Full article
(This article belongs to the Special Issue Biomass Processing for Biofuels, Bioenergy and Chemicals)
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