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Recent Advances in Biofuels Production and Usage: Challenges and Solutions

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

Deadline for manuscript submissions: closed (30 December 2024) | Viewed by 7967

Special Issue Editors

National Research and Development Institute for Gas Turbines COMOTI, 220D Iuliu Maniu, 061126 Bucharest, Romania
Interests: carbon-based materials; catalysts; biodiesel production; biofuels burning and gaseous emissions impact assessment
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Guest Editor
Faculty of Aerospace Engineering, University Politehnica of Bucharest, 1-7 Polizu Street, 1, 011061 Bucharest, Romania
Interests: biofuel use; gaseous emissions measurements; sustainability; engines parameters assessment

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Guest Editor
Romanian Research and Development Institute for Gas Turbines—COMOTI, 220D Iuliu Maniu Blvd., 061126 Bucharest, Romania
Interests: organic waste to biofuels conversion; pyrolysis; biofuels characterization and testing; gaseous emissions impact assessment

Special Issue Information

Dear Colleagues,

The 21st century is dealing with some extraordinary challenges, namely, increased energy demands and consumption, decreased fuel reserves and climate changes. The latest report on fossil fuels contribution to the global energy consumed in 2021 declares the following contributions to energy consumed: 29% crude oil, 27% coal, and 24% natural gas. Thus, 80% of consumed energy was assured by means of fossil fuels. On the other hand, from the total of 20% ensured by renewable sources (RES), 10% was biomass.

Biofuels are liquid or gaseous transport fuels, such as biodiesel and bioethanol, made from biomass. They serve as a renewable alternative to fossil fuels in the transport sector, helping to reduce greenhouse gas emissions and improve the quality of life and security of supply. Liquid biofuels are of particular interest because of the vast infrastructure already in place to use them, especially for transportation. The liquid biofuel in greatest production is ethanol (ethyl alcohol). The second most common liquid biofuel is biodiesel, which is made primarily from oily plants (such as the soybean or oil palm) and to a lesser extent from other oily sources (such as waste cooking fat from restaurant deep-frying). Biodiesel, which has found greatest acceptance in Europe, is used in diesel engines and usually blended with petroleum diesel fuel in various percentages. The use of algae and cyanobacteria as a source of “third-generation” biodiesel holds promise but has been difficult to develop economically.

We are looking for contributions in the following areas:

  • Technologies: novel/emerging technologies for biofuels production including but not limited to thermochemical, biochemical and (photo)electrochemical conversion.
  • Tools/methods: multi-/interdisciplinary approaches are particularly welcome. Both computational modelling and experimental studies are welcome and should demonstrate a holistic assessment in terms of technical, economic and environmental dimensions. We also encourage research that demonstrates resource efficiency enhancement through process integration and intensification strategies. Studies based on purely experimental research without a holistic assessment are not within the scope of this Special Issue.
  • Sustainability analysis: techno-economic analysis, life cycle assessment (LCA) and any other assessments of the novel/emerging production technologies will be considered.
  • Case studies: local/regional/national/international case studies; small/large-scale systems; and policy recommendations are also welcome.

Dr. Radu Mirea
Dr. Grigore Cican
Dr. Radu Kuncser
Guest Editors

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Keywords

  • biofuels
  • production technology solutions
  • gaseous emission
  • biodiesel use
  • catalysts for biofuels production
  • biofuels burning assessment

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Related Special Issue

Published Papers (7 papers)

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Research

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16 pages, 3024 KiB  
Article
A CHEMCAD Software Design Approach for Non-Conventional Biodiesel Production Using Methyl Acetate as Feedstock
by Letitia Petrescu, Oana Beudean, Stefan Cristian Galusnyak and Calin-Cristian Cormos
Energies 2024, 17(17), 4504; https://doi.org/10.3390/en17174504 - 8 Sep 2024
Viewed by 1911
Abstract
Biodiesel is a sustainable and renewable fuel generated from renewable resources, including vegetable oil or animal fats. It is thought to be a non-toxic fuel that degrades gradually and causes no harm to the environment. In the present study, a non-conventional supercritical method [...] Read more.
Biodiesel is a sustainable and renewable fuel generated from renewable resources, including vegetable oil or animal fats. It is thought to be a non-toxic fuel that degrades gradually and causes no harm to the environment. In the present study, a non-conventional supercritical method for industrial biodiesel production is investigated. The non-conventional method refers to a single-step interesterification reaction between triglycerides and methyl acetate resulting in methyl esters of fatty acids and triacetin as a secondary product. Process flowsheet modeling, using CHEMCAD chemical engineering software, was used as an investigation tool. The production capacity was set to 25,000 kg/h biodiesel. Methyl acetate requested in the biodiesel production is produced from methanol esterification with acetic acid using an intensified reactive distillation unit. Methanol, in turn, is obtained using synthetic gas derived from biomass as a raw material, the process representing a new method at the industrial level to solve problems related to the energy that is required, storage and disposal of residual materials, and pollution through the release of pollutants into the air. The methanol synthesis process is similar to the one based on natural gas, consisting of three main steps, namely: (i) synthesis gas production, followed by (ii) methanol production, and (iii) methanol purification. Acetic acid is an essential chemical product, generated in the proposed approach by a sustainable method with low energy consumption and low air emissions, more exactly methanol carbonylation. All the processes previously mentioned: (i) biodiesel production, (ii) methyl acetate production, (iii) acetic acid production, and (iv) methanol production were modeled and simulated, leading to the desired biodiesel productivity (e.g., 25,000 kg/h) with the obtained purity being higher than 99%. Relevant discussions regarding the design assumptions used, the simulation and validation results, as well as other technical issues (i.e., electricity and thermal energy consumption) for the system being simulated, are provided, leading to the conclusion that the proposed route is well suited for the desired application and can deliver significant results. The simulation outcomes have provided confidence in the feasibility and effectiveness of the chosen process design, making it a viable option for further development and implementation. Full article
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15 pages, 5937 KiB  
Article
Direct Hydrothermal Synthesis and Characterization of Zr–Ce-Incorporated SBA-15 Catalysts for the Pyrolysis Reaction of Algal Biomass
by Simona-Bianca Ghimiș, Florin Oancea, Monica-Florentina Raduly, Andreea-Luiza Mîrț, Bogdan Trică, Mihaela Cîlțea-Udrescu and Gabriel Vasilievici
Energies 2024, 17(15), 3765; https://doi.org/10.3390/en17153765 - 30 Jul 2024
Cited by 2 | Viewed by 1163
Abstract
In recent years, algae have emerged as a promising feedstock for biofuel production, due to their eco-friendly, sustainable, and renewable nature. Various methods, including chemical, biochemical, and thermochemical processes, are used to convert algal biomass into biofuels. Pyrolysis, a widely recognized thermochemical technique, [...] Read more.
In recent years, algae have emerged as a promising feedstock for biofuel production, due to their eco-friendly, sustainable, and renewable nature. Various methods, including chemical, biochemical, and thermochemical processes, are used to convert algal biomass into biofuels. Pyrolysis, a widely recognized thermochemical technique, involves high temperature and pressure to generate biochar and bio-oil from diverse algal sources. Various pyrolytic processes transform algal biomass into biochar and bio-oil, including low pyrolysis, fast pyrolysis, catalytic pyrolysis, microwave-assisted pyrolysis, and hydropyrolysis. These methods are utilized to convert a range of microalgae and cyanobacteria into biochar and bio-oil. In this publication, we will discuss catalytic pyrolysis using mesoporous materials, such as SBA-15. Mesoporous catalysts have earned significant attention for catalytic reactions, due to their high surface area, facilitating the better distribution of impregnated metal. Pyrolysis conducted in the presence of a mesoporous catalyst is viewed more as efficient, compared to reactions occurring within the smaller microporous cavities of traditional zeolites. SBA-15 supports with incorporated Zr and/or Ce were synthesized using the direct hydrothermal synthesis method. The catalyst was characterized using structural and morphological technical analysis and utilized for the pyrolysis reaction of the algal biomass. Full article
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24 pages, 2175 KiB  
Article
Experimental Investigation of Glycerol Derivatives and C1–C4 Alcohols as Gasoline Oxygenates
by André L. Olson, Martin Tunér and Sebastian Verhelst
Energies 2024, 17(7), 1701; https://doi.org/10.3390/en17071701 - 2 Apr 2024
Viewed by 1088
Abstract
Certain oxygenated compounds, when blended with gasoline, have the ability to inhibit the occurrence and decrease the intensity of engine knock, helping improve engine efficiency. Although ethanol has had widespread use as an oxygenate, higher alcohols, such as butanol, exhibit superior properties in [...] Read more.
Certain oxygenated compounds, when blended with gasoline, have the ability to inhibit the occurrence and decrease the intensity of engine knock, helping improve engine efficiency. Although ethanol has had widespread use as an oxygenate, higher alcohols, such as butanol, exhibit superior properties in some respects. Besides alcohols, glycerol derivatives such as glycerol tert-butyl ether (GTBE), among others, also have the potential to be used as gasoline oxygenates. This work provides a direct comparison, performed on a modified Waukesha CFR engine, of C1–C4 alcohols and the glycerol derivatives GTBE, solketal, and triacetin, all blended with a gasoline surrogate in different concentrations. The tests focused on how these oxygenated compounds affected the knocking behavior of the fuel blends, since it directly impacts engine efficiency. The test matrices comprised spark-timing sweeps at two different compression ratios, at stoichiometric conditions and constant engine speed. The results showed that, in general, the C1–C4 alcohols and the glycerol derivatives were effective in decreasing knock intensity. n-Butanol and solketal were the noteworthy exceptions, due to their demonstrated inferior knock-inhibiting abilities. On the other hand, isopropanol, isobutanol, and GTBE performed particularly well, indicating their potential to be used as gasoline oxygenates for future engines, as alternatives to ethanol. Full article
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19 pages, 6922 KiB  
Article
Synthesis of Guanidine and Its Deposition on Bacterial Cellulose as Green Heterogeneous Catalyst for Transesterification to Methyl Esters
by Cristian Eugen Răducanu, Tănase Dobre, Dan Eduard Mihăiescu, Alina Moroşan, Roxana Jidveian, Doinița Roxana Cioroiu Tîrpan, Alexandru Dan Vasiliu, Cristina Ionela Gogoaşă, Oana Cristina Pârvulescu and Bogdan Trică
Energies 2024, 17(6), 1344; https://doi.org/10.3390/en17061344 - 11 Mar 2024
Viewed by 1338
Abstract
Green catalysts used in the transesterification reaction of biodiesel must have biodegradability and non-toxicity as their main characteristics, being thus friendly to the environment, since they perform in processes in which the content of CO2, which is increasing from year to [...] Read more.
Green catalysts used in the transesterification reaction of biodiesel must have biodegradability and non-toxicity as their main characteristics, being thus friendly to the environment, since they perform in processes in which the content of CO2, which is increasing from year to year, should be reduced. As a consequence, their manufacture can be extremely rigorous. This work presents the two-step construction, synthesis, and deposition of such a green heterogeneous catalyst and its testing in the catalysis of the transesterification of triglycerides with methanol, resulting in methyl esters. A CSTR-type reactor was used to perform transesterification, and the biodiesel yields obtained had values in the range of 91.7–95.7%, using 2, 3, and 4 g/g catalyst to oil, under conditions like those for obtaining commercial biodiesel in homogeneous catalysis, i.e., a 65 °C process temperature and a 4:1, 5:1 or 6:1 methanol-to-oil molar ratio. Full article
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Review

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16 pages, 931 KiB  
Review
The Use of Jet A Aviation Fuel Blended with Biodiesel and Alcohols as a Sustainable Aviation Fuel: A Review
by Radu Mirea
Energies 2025, 18(7), 1575; https://doi.org/10.3390/en18071575 - 21 Mar 2025
Viewed by 362
Abstract
The present paper is a review of the use of different types of blends of Jet A aviation fuel with biodiesel and alcohols, respectively, as sustainable aviation fuels (SAF). The scientific literature published from 2017 to 2024 was addressed and highlighted that the [...] Read more.
The present paper is a review of the use of different types of blends of Jet A aviation fuel with biodiesel and alcohols, respectively, as sustainable aviation fuels (SAF). The scientific literature published from 2017 to 2024 was addressed and highlighted that the use of Jet A fuel blended with alcohols and biodiesel has gained attention as a potential pathway to reducing aviation emissions and enhancing sustainability. Alcohol-blended Jet A fuels, such as ethanol and methanol mixtures, offer advantages including lower carbon monoxide (CO) and unburned hydrocarbon (HC) emissions due to their improved combustion efficiency. Similarly, biodiesel blends contribute to reduced particulate matter (PM) and CO emissions, while their oxygen content promotes cleaner combustion. Both types of blends have the potential to decrease the aviation sector’s carbon footprint and enhance fuel diversification. However, several gaps and limitations remain, including lower energy density leading to increased fuel consumption, material compatibility issues, increased nitrogen oxide (NOx) emissions, and concerns over fuel stability. Further research is needed to optimize blend ratios, improve combustion control strategies, and ensure the safe and efficient integration of these alternative fuels in aviation. Full article
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17 pages, 1445 KiB  
Review
On the Exploitation of Lignin Slow Pyrolysis Products
by Guido Busca, Elena Spennati, Matteo Borella, Alessandro A. Casazza and Gabriella Garbarino
Energies 2025, 18(4), 943; https://doi.org/10.3390/en18040943 - 16 Feb 2025
Viewed by 520
Abstract
The potential of technical lignins as secondary raw materials is discussed. The characteristics of lignin pyrolysis, with particular emphasis on slow pyrolysis technologies, are briefly summarized. The slow pyrolysis process, which can be self-sustained by burning the coproduced gas, can primarily produce high-quality [...] Read more.
The potential of technical lignins as secondary raw materials is discussed. The characteristics of lignin pyrolysis, with particular emphasis on slow pyrolysis technologies, are briefly summarized. The slow pyrolysis process, which can be self-sustained by burning the coproduced gas, can primarily produce high-quality biochar in significant amounts, to be used as a fuel, as a reductant in metallurgy, and as an adsorbent and catalyst component. Together, significant amounts of bio-oil can be produced, rich in guaiacols, which are commercial and expensive chemicals produced today via petrochemical routes and used in pharmacology, food chemistry, polymer chemistry, etc. Such compounds, or bio-oil itself, can also be converted by hydrodeoxygenation into biofuels. A possible simplified flowsheet for a lignin slow pyrolysis process in the frame of a ligneocellulosics-based biorefinery is proposed. Full article
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29 pages, 964 KiB  
Review
The Gasification of Marine and Coastal Resources for Syngas Production: A Review
by Gwendal Vonk, Virginie Boy, Jean-Louis Lanoisellé and Thomas Lendormi
Energies 2025, 18(3), 616; https://doi.org/10.3390/en18030616 - 29 Jan 2025
Viewed by 729
Abstract
Coasts are home to one-third of the human population. In the process of energy transition, local biomass and waste resources represent a renewable fuel that can substitute fossil fuels in order to reduce greenhouse gas emissions, hence including marine resources as part of [...] Read more.
Coasts are home to one-third of the human population. In the process of energy transition, local biomass and waste resources represent a renewable fuel that can substitute fossil fuels in order to reduce greenhouse gas emissions, hence including marine resources as part of the eligible feedstock for renewable energy production. Gasification regroups different technologies that aim to convert a solid fuel into a useful gas, and has several applications, such as heat production, power generation, and chemical synthesis. Gasification technologies regroup the traditional “dry” processes that use relatively dry fuels, but recent developments have been made with “wet” processes such as hydrothermal gasification, in sub- or supercritical conditions for the water, which can accept wet fuel. This review focuses on scientific articles that performed gasification of marine resources in order to produce a syngas. First, a definition of marine resources is made, followed by the presentation of marine resources studied in the literature. Secondly, this review presents the different types of gasification reactors and their operating conditions, followed by a summary of the different syngas produced with their composition as a performance indicator. Finally, this review exposes the limitations of the current literature and concludes with perspective propositions. Full article
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