Investigation of Biofuel as a Potential Renewable Energy Source

In the paper

“The use of algae also has other environmental advantages, as a result of their ability to fix CO 2 , which has been proposed as a method for removing CO 2 from flue gases from power plants, thus reducing GHG emissions [29][30][31].”

What the sources say

• Not checked yetcites [29][30][31]

In the paper

“The literature suggests biofuels can negatively impact food security and production; however, this is dependent on the type of feedstock used in biofuel production.”

In the paper

“Ethanol is currently the most widely used biofuel globally, accounting for approximately 80% of all liquid biofuel production [15,16].”

What the sources say

• Not checked yetcites [15] Lee, J.W. (2013). Advanced Biofuels and Bioproducts, Springer. [1st ed.]. source
• Not checked yetcites [16] Popp, J., Harangi-Rakos, M., Gabnai, Z., Balogh, P., Antal, G., and Bai, A. (2016). Biofuels and their co-products as livestock feed: Global economic and environmental implications. Molecules, 21. source

In the paper

“Advanced biofuels, derived from inedible biomass, are heavily favoured but require further research and development to reach their full commercial potential.”

In the paper

“However, there has been little research on the economic and environmental feasibility of using algae as a biofuel feedstock, with concerns regarding its commercial-scale production.”

In the paper

“Replacing fossil fuels by biofuels can substantially reduce particulate matter (PM), carbon monoxide (CO) emissions, but simultaneously increase emissions of nitrogen oxides (NO x ), acetaldehyde (CH 3 CHO) and peroxyacetyl nitrate (PAN), resulting in debates concerning the way biofuels should be implemented.”

In the paper

“The introduction of such policies, particularly in Europe, the US and Brazil, has caused the biofuel industry to grow in the last decade with biofuels now representing around 3% of transport fuels in use globally [12,13].”

What the sources say

• Not checked yetcites [12] Eisentraut, A. (2011). Technology Roadmap—Biofuels for Transport, International Energy Agency. Available online: https://fiva.org/wp-content/uploads/2019/04/Technology-Biofuels-for-Transport.pdf.
• Not checked yetcites [13] Timilsina, 2014, Biofuels in the long-run global energy supply mix for transportation, Philos. Trans. R. Soc. A source

In the paper

“Indonesia has the potential to become the largest biofuel manufacturer in the world [45].”

What the sources say

• Not checked yetcites [45] Putrasari, 2016, Resources, policy and research activities of biofuel in Indonesia: A review, Energy Rep. source

In the paper

“Global biofuel production and consumption in 2019 increased by ~3% and ~6%, respectively, as displayed in Figure 3a,b.”

What the sources say

• Not checked yetcites [1] BP (2020). Statistical Review of World Energy, BP p.l.c.. [69th ed.]. Available online: https://www.bp.com/en/global/corporate/energy-economics/statistical-review-of-world-energy.html.

In the paper

“Increasing use of biofuel across the world is likely to make up a significant proportion of global trace VOCs in the near future.”

In the paper

“Biodiesel also has a better lubricity and is less toxic than conventional diesel, making it safer and easier to handle [57].”

What the sources say

• Not checked yetcites [57] US Department of Energy (2004). Biodiesel Handling and Use Guidelines.

In the paper

“The large-scale use of biofuel will result in direct emissions into the atmosphere via leakage, evaporation or incomplete combustion.”

In the paper

“Second, third and fourth generation biofuels are commonly referred to as 'advanced biofuels' and thought to hold many advantages over first generation fuels, but, they are still in the research and development phase and have not reached their full commercial potential.”

In the paper

“The agricultural crops (e.g., sugarcane, corn) for bioethanol production on an industrial scale led to rapid and irreversible soil degradation, water scarcity, fertilizer use and pesticide application resulting in air and water pollution, and the loss of wild and agricultural biodiversity [65].”

What the sources say

• Not checked yetcites [65] Wu, 2018, Bioenergy production and environmental impacts, GeoSci. Lett. source

In the paper

“Additionally, despite the strong agreement across the literature that a shift to advanced biofuels is needed, the reduced application of these fuels in industry makes projections of their future environmental impact difficult.”

In the paper

“Reduced food production is likely to trigger a subsequent rise in food prices, which could harm the economy and worsen food insecurity for those in poverty [11].”

What the sources say

• Not checked yetcites [11] Arutyunov, 2017, Energy resource of the 21st century: Problems and forecasts. Can renewable energy source replace fossil fuels?, Russ. Chem. Rev. source

In the paper

“Reduced GHG emissions would lead to a lower global temperature, which could both increase crop yield and the quality of crops grown [56].”

What the sources say

• Not checked yetcites [56] Subramaniam, 2020, Biofuels, environmental sustainability and food security: A review of 51 countries, Energy Res. Soc. Sci. source

In the paper

“Biofuels also have higher production costs in the current market due to requirement of more intensive processing procedures and, as with increased agriculture of any form, the production and end use of biofuels comes with concerns of deforestation, biodiversity loss and increased fertilizer and pesticide use [60].”

What the sources say

• Not checked yetcites [60] Webb, A., and Coates, D. (2012). Biofuels and Biodiversity. Secretariat of the Convention on Biological Diversity, Secretariat of the Convention on Biological Diversity.

In the paper

“Biofuels have both positive and negative effects on the economy, environment and public health [52]; many studies suggest it is crucial that governments across the globe rigorously consider these impacts prior to any future biofuel investments or implementation strategies [53,54].”

What the sources say

• Not checked yetcites [52] Mizik, 2021, Economic and sustainability of biodiesel production- A systematic literature review, Clean Technol. source

In the paper

“However, EROEI for the production of ethanol from sugarcane in Brazil is 5 to 10, suggesting sugarcane ethanol production in Brazil costs less than that in US [50,51] and Brazil would benefit with using biofuel as energy source.”

What the sources say

• Not checked yetcites [50] Goldemberg, 2007, Ethanol for a sustainable energy future, Science source
• Not checked yetcites [51] Carpintero, 2014, A top-down approach to assess physical and ecological limits of biofuels, Energy source

In the paper

“For instance, Brazilian biofuel production between 2005 and 2014 was estimated at 17.4 billion L, saving 12.9 billon US dollars in fossil fuel import costs [39].”

What the sources say

• Not checked yetcites [39] Coelho, 2017, History, evolution and environmental impact of biodiesel in Brazil: A review, Renew. Sust. Energ. Rev. source

In the paper

“Instead of solely relying on one generation of biofuel, the best approach may be a combination of resources to manage the increasing global demand [48].”

What the sources say

• Not checked yetcites [48] Lee, 2013, From first- to third-generation biofuels: Challenges of producing a commodity from a biomass of increasing complexity, Anim. Front. source

In the paper

“However, there are challenges to commercialize the large-scale production of these advanced biofuels as the cost of production is high and the performance of current conversion technologies requires improvement [47,68].”

What the sources say

• Not checked yetcites [47] Aro, 2016, From first generation biofuels to advanced solar biofuels, Ambio source
• Not checked yetcites [68] Milano, 2016, Microalgae biofuels as an alternative to fossil fuel for power generation, Renew. Sust. Energ. Rev. source

In the paper

“Additional benefits have been recognized when using microalgae as a feedstock, such as faster biomass production, high oil content and a capability to grow throughout the year in both natural and artificial environments [67].”

What the sources say

• Not checked yetcites [67] Sharma, 2020, Sustainable environmental management and related biofuel technologies, J. Environ. Manag. source

In the paper

“A considerable amount of research on biofuels as a renewable energy source is inconclusive and contradictory [38][39][40][41].”

What the sources say

• Not checked yetcites [38][39][40][41]

In the paper

“Despite first generation biofuels being successfully implemented globally, recent studies highlighted negative consequences of expanding their production further and argue for a greater effort on the production of advanced biofuels [46][47][48].”

What the sources say

• Not checked yetcites [46][47][48]

In the paper

“In addition, not all countries have large crude oil reserves so a shift towards biofuel production would allow countries to reduce both their dependence on fossil fuels and, consequently, their import costs.”

In the paper

“In spite of these benefits, several problems stand in the way of using biofuels as a replacement to fossil fuels, for example, comparing with diesel, biodiesel has a lower calorific value, higher NO x emissions, higher copper strip corrosion and fuel pumping difficulty [58,59].”

What the sources say

• Not checked yetcites [58] Agarwal, 2006, Experimental investigation of control of NOx emissions in biodiesel-fueled compression ignition engine, Renew. Energy source
• Not checked yetcites [59] Demirbas, 2009, Progress and recent trends in biodiesel fuels, Energy Conv. Manag. source

In the paper

“Biofuels are often sold in the global market as blends with fossil fuels, in order to be compatible with conventional vehicle engines and reduce the need for additives [43].”

What the sources say

• Not checked yetcites [43] Yusoff, 2020, Sustainability of Palm biodiesel in transportation: A review on biofuel standard, policy and international collaboration between Malaysia and Colombia, BioEnergy Res. source

In the paper

“Biofuel production as an alternative of natural fossil fuel could destroy the natural ecosystem and violate the equilibrium of global biosphere processes.”

In the paper

“Brazil has successfully implemented public policies to increase biofuel consumption and in turn improve air quality.”

In the paper

“Initially, this takes place via a H-abstraction reaction which can occur at different reaction sites along ethanol [96].”

What the sources say

• Not checked yetcites [96] Atkinson, 2006, IUPAC Subcommittee. Evaluated kinetic and photochemical data for atmospheric chemistry: Volume II- gas phase reactions of organic species, Atmos. Chem. Phys. source

In the paper

“a recent report released by the Brazilian Department of Agriculture Livestock Supply states that by “adding up all the biodiesel consumed in Brazil since 2008, the GHG avoided emissions have already reached 21.8 million tons of CO 2 , which is equivalent to nearly 158 million trees in an area corresponding to 144 thousand football fields” [39,76].”

What the sources say

• Not checked yetcites [39] Coelho, 2017, History, evolution and environmental impact of biodiesel in Brazil: A review, Renew. Sust. Energ. Rev. source
• Not checked yetcites [76] Brazil Ministry of Agriculture, Livestock and Supply (2021, August 30). Benefícios Ambientais da Produção e do USO do Biodiesel. Brazil, Available online: https://ubrabio.com.br/sites/1800/1891/PDFs/BenefAciosAmbientaisdaProduAAoeUsodoBiod.pdf.

In the paper

“The initial degradation of ethanol involves the direct breakage of the C-C bond forming the hydroxymethyl radical, which either reacts with oxygen or decomposes in the atmosphere, to produce formaldehyde [95].”

What the sources say

• Not checked yetcites [95] Zhu, 2013, Effects of ethanol-biodiesel blend and diesel oxidation catalyst (DOC) on particulate and unregulated emissions, Fuel source

In the paper

“Although biofuels are still producing CO 2 , the carbon footprint is smaller as biomass feedstocks act as a carbon sink by absorbing CO 2 for photosynthesis during crop growth [40,75].”

What the sources say

• Not checked yetcites [40] Muhammad, 2018, Biofuels as the starring substitute to fossil fuels, Pet. Sci. Eng.
• Not checked yetcites [75] Porqueras, 2012, Biofuels and CO2 neutrality: An opportunity, Biofuels source

In the paper

“For instance, delaying fuel injection, addition of water in biofuel blends, and a medium engine speed are all potential ways to decrease NO x pollution [53,89,91].”

What the sources say

• Not checked yetcites [53] AQEG (2021, August 30). Road Transport Biofuels: Impact on UK Air Quality, Available online: https://www.gov.uk/government/publications/road-transportbiofuels-impact-on-uk-air-quality.
• Not checked yetcites [89] Tan, 2017, Engine performance and emissions characteristics of a diesel engine fueled with diesel-biodiesel-bioethanol emulsions, Energy Convers. Manag. source
• Not checked yetcites [91] Gharehghani, 2019, Simulataneous reduction of CO and NOx emissions as well as fuel consumption by using water and nano particles in diesel-biodiesel blend, J. Clean. Prod. source

In the paper

“The main explanation for these reduced emissions within literature is that the higher oxygen content of ethanol and biodiesel, compared with petrol and diesel [73,74], leads to a more complete combustion and hence a decrease in particulate content and exhaust gas [11].”

What the sources say

• Not checked yetcites [73] Varol, 2014, Comparison of methanol, ethanol, or n-butanol blending with unleaded gasoline on exhaust emissions of an SI engine. Energy Sources, Part A: Recovery, Util. Environ. Eff.
• Not checked yetcites [74] Giakoumis, 2014, Assessment of NOx emissions during transient diesel engine operation with biodiesel blends, J. Energy Eng. source
• Not checked yetcites [11] Arutyunov, 2017, Energy resource of the 21st century: Problems and forecasts. Can renewable energy source replace fossil fuels?, Russ. Chem. Rev. source

In the paper

“This inconsistency between literature is understandable due to the complexity of combustion and the variation between different studies such as: engine type, vehicle age, fuel injection strategy and other conditions, which influence emissions [53,90].”

What the sources say

• Not checked yetcites [53] AQEG (2021, August 30). Road Transport Biofuels: Impact on UK Air Quality, Available online: https://www.gov.uk/government/publications/road-transportbiofuels-impact-on-uk-air-quality.
• Not checked yetcites [90] Tabatabaei, 2018, A comprehensive review on the environmental impacts of diesel/biodiesel additives, Energy Convers. Manag. source

In the paper

“Approximately 85% of the abstraction occurs at the α-site of ethanol.”

What the sources say

• Not checked yetcites [96] Atkinson, 2006, IUPAC Subcommittee. Evaluated kinetic and photochemical data for atmospheric chemistry: Volume II- gas phase reactions of organic species, Atmos. Chem. Phys. source

In the paper

“Reaction with OH involves H-abstraction from the carbonyl carbon to form a peroxyacetyl radical which can go on to react with NO 2 and produce PAN [98,99].”

What the sources say

• Not checked yetcites [98] Tanner, 1988, Atmospheric chemistry of aldehydes: Enhanced peroxyacetyl nitrate formation from ethanol-fueled vehicular emissions, Environ. Sci. Technol. source
• Not checked yetcites [99] Gaffney, 1997, Potential air quality effects of using ethanol-gasoline fuel blends: A field study in Albuquerque, New Mexico, Environ. Sci. Technol. source

In the paper

“with many also reporting a strong association with mortality across the world [86][87][88].”

What the sources say

• Not checked yetcites [86][87][88]

In the paper

“PAN is a key contributor to photochemical smog, typically in warm summer climates, which consequently causes eye irritation and respiratory issues [53].”

What the sources say

• Not checked yetcites [53] AQEG (2021, August 30). Road Transport Biofuels: Impact on UK Air Quality, Available online: https://www.gov.uk/government/publications/road-transportbiofuels-impact-on-uk-air-quality.

In the paper

“According to the Air Transport Action Group, a key part of the aviation sector's carbon-neutral growth strategy is the use of low-carbon, sustainable aviation fuels, which have bio-based components [117].”

What the sources say

• Not checked yetcites [117] Kousoulidou, 2016, Biofuels in aviation: Fuel demand and CO2 emissions evolution in Europe toward 2030, Transp. Res. Part. D Transp. Environ. source

In the paper

“An example of a potential environmental barrier could be the implications of land-use changes which may be required to grow sufficient amounts of biofuel feedstock to meet the demand.”

In the paper

“A study undertaken by Jacobson [104] also showed that such a blend causes elevations in the levels of PAN, whilst also increasing ozone-related mortality.”

What the sources say

• Not checked yetcites [104] Jacobson, 2007, Effects of ethanol (E85) versus gasoline vehicles on cancer and mortality in the United States, Environ. Sci. Technol. source

In the paper

“Investigation into biomass feedstocks has presented issues associated with preparation, as many feedstocks are highly oxygenated, while jet fuels are required to be fully deoxygenated hydrocarbons.”

In the paper

“Before the Fischer-Tropsch synthesis, the syngas must be purified and adjusted to ensure the syngas ratios of CO and H 2 are appropriate for FT.”

In the paper

“Consequently, aviation fuel consumption currently accounts for 3% of the total global fossil fuels used [116].”

What the sources say

• Not checked yetcites [116] Lee, 2010, Can we accelerate the improvement of energy efficiency in aircraft systems?, Energy Convers. Manag. source

In the paper

“Biofuels must therefore involve chemical transformation to selectively remove oxygen and structural adjustments.”

In the paper

“Other areas of the globe with higher ethanol mixing ratios include the south-eastern U.S.A., East Asia (areas of China) and South Asia (around India).”

What the sources say

• Not checked yetcites [102] Khan, 2017, An estimate of the global budget and distribution of ethanol using a global 3-D atmospheric chemistry transport model STOCHEM-CRI, Trans. Royal Soc. S. Afr. source

In the paper

“Therefore, this application of biofuels is helping to remove harmful waste gases such as CO 2 , whilst simultaneously producing electricity which could later be used to power battery-driven vehicles in a non-polluting way [113].”

What the sources say

• Not checked yetcites [113] Consoli, C. (2019). Bioenergy and Carbon Capture Storage, Global CCS Institute. Available online: http://www.globalccsinstitute.com/wp-content/uploads/2019/03/BECCS-Perspective_FINAL_PDF.pdf.

In the paper

“Many airlines are currently involved in research efforts to enable the implementation of these biofuels and reduce the carbon footprint of aviation [118].”

What the sources say

• Not checked yetcites [118] Mohsin, 2017, Assessment of Biofuels in Aviation Industry for Environmental Sustainability, Chem. Eng. Trans.

In the paper

“Once synthesised, the crude product is processed, which involving both cracking and separation techniques [123].”

What the sources say

• Not checked yetcites [123] Blakey, 2011, Aviation gas turbine alternative fuels: A review, Proc. Combust. Inst. source

In the paper

“Biofuel use in road transportation alone is unlikely to reduce GHG emissions sufficiently to achieve the Paris Agreement climate target, hence a wider application across the transport sector is necessary.”

In the paper

“Although this technique is well-developed, the specific composition of the gas stream is hard to control as impurities may be present in the feedstock, these include N 2 , chlorine (Cl) and tar.”

In the paper

“It is currently estimated that the demand for conventional aviation fuels (CAF), such as Jet A and Jet A-1 (comprise of 20% naphthalene, 20% paraffins, 40% iso-paraffins and 20% aromatic compounds from the crude distillate), will continue to grow to 860 Mt/year by 2050, which is more than 4 times the demand observed in 2010 [115].”

What the sources say

• Not checked yetcites [115] Chiaramonti, 2019, Sustainable Aviation Fuels: The challenge of decarbonization, Energy Procedia source

In the paper

“The aviation industry emits approximately 700 million tonnes of CO 2 eq and is accountable for almost 12% of transportation emissions worldwide [114].”

What the sources say

• Not checked yetcites [114] Chuck, C. (2016). Biofuels for Aviation: Feedbacks, Technology and Implementation, Academic Press.

In the paper

“This increases the cost and time of this process, which poses a problem for commercial-scale implementation [120].”

What the sources say

• Not checked yetcites [120] Díaz-Pérez, M.A., and Serrano-Ruiz, J.C. (2020). Catalytic production of jet fuels from biomass. Molecules, 25. source

In the paper

“The FT reaction has been extensively studied, and it has been shown FT-SPK produced contains a high concentration of long chain paraffins, both branched and unbranched, which are produced from syngas in the presence of iron or cobalt catalysts.”

In the paper

“Palm oil and many crops obtained from deforestation are not encouraged as these cause further environmental damage in different sectors [120].”

What the sources say

• Not checked yetcites [120] Díaz-Pérez, M.A., and Serrano-Ruiz, J.C. (2020). Catalytic production of jet fuels from biomass. Molecules, 25. source

In the paper

“Jet fuel alternatives (e.g., fuels derived from biomass) must also be utilised at low temperatures and also display high energy density to supply the energetic demand of long-haul flights, properties which biodiesels do not display [120].”

What the sources say

• Not checked yetcites [120] Díaz-Pérez, M.A., and Serrano-Ruiz, J.C. (2020). Catalytic production of jet fuels from biomass. Molecules, 25. source

In the paper

“Photolysis yields HCO and CH 3 radicals, where HCO instantly forms HO 2 radicals on reaction with O 2 .”

What the sources say

• Not checked yetcites [100] Khan, 2015, The global atmospheric budget and distribution of acetone using the 3-D global model, STOCHEM-CRI, Atmos. Environ. source
• Not checked yetcites [101] Khan, 2017, Global budget and distribution of peroxyacetyl nitrate (PAN) for present and preindustrial scenarios, Int. J. Earth Environ. Sci. source
• Not checked yetcites [102] Khan, 2017, An estimate of the global budget and distribution of ethanol using a global 3-D atmospheric chemistry transport model STOCHEM-CRI, Trans. Royal Soc. S. Afr. source

In the paper

“In 2018, aviation biofuel production was around 15 million L, which accounted for under 0.1% of total aviation fuel consumption [119].”

What the sources say

• Not checked yetcites [119] Le Feuvre, P. (2019). Are Aviation Biofuels Ready for Take-Off?, IEA. Available online: https://www.iea.org/commentaries/are-aviation-biofuels-ready-for-take-off.

In the paper

“The gasification process requires conversion of biomass feedstock lignocellulose into syngas under high-temperature conditions while controlling the oxidant species present [120].”

What the sources say

• Not checked yetcites [120] Díaz-Pérez, M.A., and Serrano-Ruiz, J.C. (2020). Catalytic production of jet fuels from biomass. Molecules, 25. source

In the paper

“Currently, there are many alternative fuels suggested that could help decarbonise the aviation industry and thus reduce the environmental impact of the sector [120].”

What the sources say

• Not checked yetcites [120] Díaz-Pérez, M.A., and Serrano-Ruiz, J.C. (2020). Catalytic production of jet fuels from biomass. Molecules, 25. source

In the paper

“Khan et al. [102] showed that an increased emission flux (~11.5 Tg/year) of ethanol as a biofuel and from vegetation can cause an increment of acetaldehyde by up to 30% in areas such as Brazil, Australia and Indonesia (Figure 5a) which led to an increase in PAN (by up to 3%) over the ocean near to acetaldehyde source regions (Figure 5b).”

What the sources say

• Not checked yetcites [102] Khan, 2017, An estimate of the global budget and distribution of ethanol using a global 3-D atmospheric chemistry transport model STOCHEM-CRI, Trans. Royal Soc. S. Afr. source

In the paper

“For example, the Drax power station in the U.K. has recently converted four of its six generating units from coal to wood pellets and operates carbon capture and storage (CCS) technologies alongside power generation [112].”

What the sources say

• Not checked yetcites [112] Clayton, 2019, Drax group’s bioenergy CCS (BECCS) project, Greenh. Gas. Sci. Technol. source

In the paper

“To be sustainable, BAF must be produced from sustainable feedstocks.”

In the paper

“Biomass Alternative Fuels (BAF) are synthetic paraffinic kerosene's (SPK) which can be blended with CAF [121].”

What the sources say

• Not checked yetcites [121] Doliente, 2020, Bio-aviation fuel: A comprehensive review and analysis of the supply chain components, Front. Energy Res. source

In the paper

“Snåre et al. [130] further investigated this catalytic reactivity, identifying a greater variety of catalysts that could be used for deoxygenation processes, including Pd/C.”

What the sources say

• Not checked yetcites [130] Murzin, 2006, Heterogeneous catalytic deoxygenation of stearic acid for production of biodiesel, Ind. Eng. Chem. Res. source

In the paper

“As algae are known to have a high yield production and function at low water and fertilizer concentrations, this could be a cost-effective solution [137].”

What the sources say

• Not checked yetcites [137] Fortier, 2014, Life cycle assessment of bio-jet fuel from hydrothermal liquefaction of microalgae, Appl. Energy source

In the paper

“Although often camelina crops are grown in rotation with wheat crops, where land would otherwise be left to refresh itself, this still presents a problem as the feedstock would only be available seasonally [132].”

What the sources say

• Not checked yetcites [132] Ruiz, 2013, Biodiesel from Camelina sativa: A comprehensive characterization, Fuel source

In the paper

“This employed the use of Grubb's catalyst for the alkene cross-metathesis and Pt/ZSM-22 catalyst for hydrodeoxygenation.”

What the sources say

• Not checked yetcites [131] Wang, 2018, Highly efficient conversion of plant oil to bio-aviation fuel and valuable chemicals by combination of enzymatic transesterification, olefin cross-metathesis, and hydrotreating, Biotechnol. Biofuels source

In the paper

“Currently, only iso-butanol and ethanol are used in ATJ-SPK processes, but, future development hopes to incorporate all C2-C5 alcohols in the production process [122].”

What the sources say

• Not checked yetcites [122] Yang, 2019, An overview on performance characteristics of bio-jet fuels, Fuel source

In the paper

“These free fatty acid chains must be catalytically deoxygenated through hydrodeoxygenation reactions or decarboxylation reactions resulting in long linear alkanes, as seen in Scheme 2”

In the paper

“This occurred in the presence of either N 2 or H 2 providing less stringent reactive components with a greater extent of carboxylation under N 2 atmosphere.”

What the sources say

• Not checked yetcites [129] Takemura, 1985, Catalytic decarboxylation of benzoic acid, Ind. Eng. Chem. Prod. Res. Dev. source

In the paper

“Development into these conditions could increase the number of aromatic components produced this way [135].”

What the sources say

• Not checked yetcites [135] Verma, 2015, Diesel and aviation kerosene with desired aromatics from hydroprocessing of Jatropha oil over hydrogenation catalysts supported on hierarchical mesoporous SAPO-11, Appl. Catal. A source

In the paper

“The structure of β-farnesene and is displayed in Scheme 3 and typically is produced from sugarcane and lignocellulosic biomass.”

In the paper

“As environmental conscience has increased, several reports have detailed the potential use of waste cooking oils in the formation of alternative jet fuels.”

In the paper

“Research conducted by Wang et al. [131] reported an efficient 4-step conversion method for synthesising HEFA-SPK.”

What the sources say

• Not checked yetcites [131] Wang, 2018, Highly efficient conversion of plant oil to bio-aviation fuel and valuable chemicals by combination of enzymatic transesterification, olefin cross-metathesis, and hydrotreating, Biotechnol. Biofuels source

In the paper

“These steps include enzyme transesterification, catalytic transfer hydrogenation, alkene cross-metathesis and catalytic hydrodeoxygenation.”

What the sources say

• Not checked yetcites [131] Wang, 2018, Highly efficient conversion of plant oil to bio-aviation fuel and valuable chemicals by combination of enzymatic transesterification, olefin cross-metathesis, and hydrotreating, Biotechnol. Biofuels source

In the paper

“The formation of aromatic paraffins is important for use in jet fuels as they contribute to ensuring valves in engine systems are sealed properly by promoting swelling of the valve [120].”

What the sources say

• Not checked yetcites [120] Díaz-Pérez, M.A., and Serrano-Ruiz, J.C. (2020). Catalytic production of jet fuels from biomass. Molecules, 25. source

In the paper

“This method was highly efficient and provided a more economically feasible solution compared with previously reported hydrotreatment processes.”

What the sources say

• Not checked yetcites [131] Wang, 2018, Highly efficient conversion of plant oil to bio-aviation fuel and valuable chemicals by combination of enzymatic transesterification, olefin cross-metathesis, and hydrotreating, Biotechnol. Biofuels source

In the paper

“The literature has reported promising results from the vegetable oils processed into jet fuels, with many reports indicating these fuels have been already blended with CAF to power commercial jets [120].”

What the sources say

• Not checked yetcites [120] Díaz-Pérez, M.A., and Serrano-Ruiz, J.C. (2020). Catalytic production of jet fuels from biomass. Molecules, 25. source

In the paper

“Takemura et al. [129] reported Ni and Pd catalysts with aluminium supports were useful for forming aromatic paraffins, particularly through decarboxylation of benzoic acid in a batch autoclave.”

What the sources say

• Not checked yetcites [129] Takemura, 1985, Catalytic decarboxylation of benzoic acid, Ind. Eng. Chem. Prod. Res. Dev. source

In the paper

“Typically, highly oxygenated sugar molecules, containing OH, CO and COOH groups, have a carbon number of 6.”

In the paper

“Nevertheless, this process uses an expensive feedstock and the production of the fuel is a high energy process, implantation of HFS-SIP fuels on a commercial scale would be extremely costly [138].”

What the sources say

• Not checked yetcites [138] Bauen, 2020, Sustainable aviation fuels, Johns. Matthey Technol. Rev. source

In the paper

“Additionally, reports have recommended that the cost of production could be reduced if propane, produced during the hydroprocessing stage, was sold back to for use in industry [136].”

What the sources say

• Not checked yetcites [136] Caballero, 2017, Microbial alkane production for jet fuel industry: Motivation, state of the art and perspectives, Microb. Biotechnol. source

In the paper

“Further research has been conducted recently in processing fatty acids into aromatics and cycloalkanes, components also present in CAF.”

In the paper

“The abundance of catalysts available for this process give the potential for mass implementation of these routes within the biofuel aviation industry.”

In the paper

“Conversion of alcohol to jet synthetic paraffinic kerosene involves three key steps involving dehydration to remove heteroatom oxygen to produce alkenes, oligomerisation to increase the carbon chain length of the alkenes and finally hydrogenation to produce the unsaturated long chain alkanes [125].”

What the sources say

• Not checked yetcites [125] 2017, A review on the production processes of renewable jet fuel, Renew. Sustain. Energy Rev. source

In the paper

“Both ethanol and iso-butanol are easily dehydrated in the presence of acid catalysts such as silica-alumina and at moderate temperatures, e.g., 250 °C and 325 °C, respectively [140].”

What the sources say

• Not checked yetcites [140] Hu, 2010, Selective dehydration of bio-ethanol to ethylene catalyzed by lanthanum-phosphorous-modified HZSM-5: Influence of the fusel, Biotechnol. J. source

In the paper

“Sugar molecules have also been reported as potential feedstocks for production of alternative fuels.”

In the paper

“Furthermore, a wide range of vegetable oil feedstocks have been reported, these include camelina, canola rapeseed, soybean and jatropha oils, although production of jet fuels utilising these oils is controversial as the production is not entirely sustainable [120].”

What the sources say

• Not checked yetcites [120] Díaz-Pérez, M.A., and Serrano-Ruiz, J.C. (2020). Catalytic production of jet fuels from biomass. Molecules, 25. source

In the paper

“As a non-edible crop, camelina possesses a high oil content, but, growing this crop purely for oil uses poses a question regarding feedstock availability and land use concerns [120].”

What the sources say

• Not checked yetcites [120] Díaz-Pérez, M.A., and Serrano-Ruiz, J.C. (2020). Catalytic production of jet fuels from biomass. Molecules, 25. source

In the paper

“Hydrogenation of β-farnesene produces farnesane which is an alkane which has displayed potential as a high energy density alternative fuel option [139].”

What the sources say

• Not checked yetcites [139] Liu, 2018, Renewable production of high density jet fuel precursor sesquiterpenes from Escherichia coli, Biotechnol. Biofuels source

In the paper

“Extraction of sugars from non-edible feedstocks, namely lignocellulose, require several stages of processing and poses a problem as the structure of the lignin surrounding the cellulose must be weakened before extraction which is a costly process [125].”

What the sources say

• Not checked yetcites [125] 2017, A review on the production processes of renewable jet fuel, Renew. Sustain. Energy Rev. source

In the paper

“iso-butanol has a lower water absorption and higher energy density than ethanol, however, it is still much lower than CAF [142].”

What the sources say

• Not checked yetcites [142] Wang, W., Tao, L., Markham, J., Zhang, Y., Tan, E., Batan, L., Biddy, M., Wang, W.-C., Tao, L., and Zhang, Y. (2021, August 30). Review of Biojet Fuel Conversion Technologies, Available online: https://www.nrel.gov/docs/fy16osti/66291.pdf.

In the paper

“However, the impact of aviation biofuels on other environmental factors, such as biodiversity and air quality remains uncertain and requires further investigation.”

In the paper

“Ethanol, in particular, cannot be used directly in aircraft engines due to its high volatility, high water absorption and a much lower energy density than CAF”

What the sources say

• Not checked yetcites [142] Wang, W., Tao, L., Markham, J., Zhang, Y., Tan, E., Batan, L., Biddy, M., Wang, W.-C., Tao, L., and Zhang, Y. (2021, August 30). Review of Biojet Fuel Conversion Technologies, Available online: https://www.nrel.gov/docs/fy16osti/66291.pdf.

In the paper

“HFS-SIP fuels provide a simple direct sugar-to-hydrocarbon process employing microorganisms and avoiding multi-step processing.”