Aviation Biofuels Research Articles

Synthesis of high-grade Jet fuel blending precursors by aldol condensation of lignocellulosic ketones using HfTPA/MCM-41 with strong acids and enhanced stability

Upgrading lignocellulosic ketones to Jet fuel precursors by aldol condensation is the key step for the synthesis of high-grade bio-Jet fuels. State-of-art works are confined in pure feedstock used, catalysis sites leaching and coking. Therefore, we synthesized a strong solid acid HfTPA/MCM-41 and used it to catalyze aldol condensation of lignocellulosic ketone mixture to bio-jet fuel blending precursors, where 80 %Hf1.5TPA/MCM-41 shows better activity than 80 %HPW/MCM-41 and commercial zeolites with 66.8 % yield of products obtained. The good performance of the catalyst is ascribed to good acid properties, large surface area and especially new strong L acids and good stability based on anti-coking and water tolerance by Hf doping, which changes the electronic structure of the catalyst surface to efficiently activate CO bond of ketones to form a metal enolate intermediate and anchoring HPW from leaching. This work demonstrates an efficient way to synthesize high-performance acid catalyst applied in bio-jet fuel synthesis.

Development of a hybrid biorefinery for jet biofuel production

Jet biofuel (JBF) is identified as an essential solution to mitigate the carbon footprint of the aviation sector. Since aeroplanes rely solely on liquid fuels, the development of pathways that generates JBF as a major product has become crucial. Thus far, seven pathways to produce JBF have been developed and certified over the past decade. Each of these pathways accommodates a specific type of biomass. However, the availability, sustainability and feasibility of feedstocks to fulfil the growing demand on jet fuel remains an issue. As such, this study presents a holistic approach for the design of a state-of-the-art hybrid biorefinery that accommodates multiple biomass feedstocks across different categories including energy crops (i.e., Jatropha energy crop), dry biomass (i.e., municipal solid waste) and wet biomass (i.e., livestock manure). A Qatar-based industrial scale biorefinery was modelled in Aspen Plus® considering a pre-defined geospatial distribution of biomass and the optimal biorefinery site in the country. The hybrid system integrated advanced technologies such as hydroprocessing, Fischer-Tropsch, gasification, dry-reforming and hydrothermal liquefaction. While biomass optimal insertion streams were evaluated using a prediction model. Besides, intensive materials, heat, water and power integrations were performed to maximise JBF production, mitigate its environmental impact and control its cost. The system generated 328, 94 and 44 million litres of JBF, gasoline and diesel, respectively. Produced JBF was characterised and found to comply with all international standards. The generated JBF can substitute 15.3 % of Qatar’s jet fuel needs, while it can power around one third of its fleet considering a maximum allowable jet biofuel blend of 50 %. The proposed model achieved a minimum selling price of JBF at 0.43 $/kg, which is 22 % lower than the market price of conventional Jet-A fuel (2019). In addition, the environmental analysis of the model indicated a 41 % mitigation in greenhouse gas emissions achieved by JBF throughout its lifecycle, relative to Jet-A fuel.

Multiomics and optobiotechnological approaches for the development of microalgal strain for production of aviation biofuel and biorefinery

Demand and consumption of fossil fuels is increasing daily, and oil reserves are depleting. Technological developments are required towards developing sustainable renewable energy sources and microalgae are emerging as a potential candidate for various application-driven research. Molecular understanding attained through omics and system biology approach empowering researchers to modify various metabolic pathways of microalgal system for efficient extraction of biofuel and important biomolecules. This review furnish insight into different “advanced approaches” like optogenetics, systems biology and multi-omics for enhanced production of FAS (Fatty Acid Synthesis) and lipids in microalgae and their associated challenges. These new approaches would be helpful in the path of developing microalgae inspired technological platforms for optobiorefinery, which could be explored as source material to produce biofuels and other valuable bio-compounds on a large scale.

Anodic Cross-Coupling of Biomass Platform Chemicals to Sustainable Biojet Fuel Precursors

Electrocatalytic conversion of biomass platform chemicals to jet fuel precursors is a promising approach to alleviate the energy crisis caused by the excessive exploitation and consumption of non-renewable fossil fuels. However, an aqueous electrolyte has been rarely studied. In this study, we demonstrate an anodic electrocatalysis route for producing jet fuel precursors from biomass platform chemicals on Ni-based electrocatalysts in an aqueous electrolyte at room temperature and atmosphere pressure. The desired product exhibited high selectivity for the jet fuel precursor (95.4%) and an excellent coulombic efficiency of 210%. A series of in situ characterizations demonstrated that Ni2+ species were the active sites for the coupling process. In addition, the coupling reaction could be achieved by generating radical cations and inhibiting the side reaction. First, the electrochemical process could activate the furfural (FF) molecule and generate radical cations, resulting in an average of 2.0 times chain propagation. The levulinic acid (LA) molecules played a vital role in the coupling reaction. The adsorption strength of LA on Ni3N was higher than that of FF, which could inhibit the side reaction (the oxidation of FF) and achieve high selectivity. Meanwhile, the LA molecules were adsorbed on the Ni3N surface and then disrupted the formation of Ni3+ species, thus favoring the coupling reaction. This work demonstrates an efficient route to produce jet fuel precursors directly from biomass platform chemicals and provides a comprehensive understanding of the anodic coupling process.

Evaluation of spray characteristics of aviation biofuels and Jet A-1 from a hybrid airblast atomizer

Studies on the atomization characteristics of sustainable aviation fuels (SAF) such as drop-in aviation biofuels from aircraft engine atomizers are essential to counter the rise in aviation-caused CO2 emissions in the atmosphere. The present study analyses the drop size characteristics of fuel sprays of camelina- and jatropha-derived drop-in aviation biofuels from a hybrid airblast atomizer (HAA) used in aircraft engines. To begin with salient details of hybrid atomization are studied through experiments using water at different liquid and air flow rates. The spray characterization work of four different drop-in aviation biofuels, derived through the blending of camelina/jatropha HRJ biofuels and Jet A-1, from the HAA is done subsequently. The fuel spray experiments are carried out at six test conditions. The mean drop size (Sauter mean diameter, SMD) variations of the HAA spray are compared with predictions obtained from correlations reported in the literature. Likewise, the SMD trends of the hybrid atomization are compared with that of the simplex swirl atomization. Using the current data of the HAA spray of six experimental fluids, a new correlation for non-dimensionalized SMD in terms of liquid and air Weber numbers and Ohnesorge number is proposed, which facilitates the determination of mean droplet size of futuristic alternative aviation fuel sprays from the hybrid airblast atomizers.

Quantitative synergy between metal and acid centers over the Ni/Beta bifunctional catalyst for methyl laurate hydrodeoxygenation to bio-jet fuel

The synergistic effect of metal and acid centers influences performance of bifunctional hydrodeoxygenation (HDO) catalyst significantly. However, seldom work concerning this point has been performed quantitatively. Herein, the Ni/Beta catalysts were prepared for HDO of methyl laurate to bio-jet fuels. The ratios of metal to acid centers (nNi/nA) were used to quantitatively express the synergistic effect and correlated to the HDO performance. The transformation of methyl laurate mainly stagnates at fatty acid over the mono-functional catalyst (nNi/nA = 0), while the acid centers are indispensable for the efficient transformation of methyl laurate at relatively mild reaction conditions. The TOF and selectivity to C11 and C12 alkanes increase and then keep constant with the increasing nNi/nA. The turning point at the nNi/nA of 0.67 implies that one nickel center over the Ni/Beta catalyst can balance ca. 1.5 acid centers in the HDO of methyl laurate. Besides, the higher nNi/nA favors the HDO reaction pathway compared with the decarbonylation or decarboxylation ones. It increases the selectivity to C12 alkanes and improves efficiency of atomic utilization during the hydrodeoxygenation of methyl laurate. This work provides a deeper insight into the quantitative synergy of active sites over the bifunctional HDO catalyst for production of bio-fuels.

Solvent extraction and characterization of Brassica carinata oils as promising alternative feedstock for bio-jet fuel production.

As a fossil fuel substitute, bio-jet fuel derived from inedible oilseed crops has the potential to improve energy security, decrease carbon footprint, and promote agricultural economy and social development. The efficient production of bio-jet fuels depends on the identification and characterization of eco-friendly and sustainable feedstocks. Brassica carinata (Arun Braun) cultivars are among the most significant industrial oilseeds that can be utilized as alternative feedstocks in the aviation industry. The study thoroughly evaluated four non-food Brassica carinata cultivars that are indigenous to Ethiopia to determine their suitability as substitute feedstocks for the production of bio-jet fuel. The effects of solvent extraction parameters were studied using response surface methodology with Box-Behnken design in an isothermal batch reactor. Physicochemical characterization, fatty acids profiling, ultimate analysis, analysis of metals and phosphorus concentration, Fourier-transform infrared spectroscopy characterization, and calorific value analyses were performed to characterize the properties of oils. Accordingly, oil yields ranged from 35.93 to 45.25%. Erucic acid (EA) was the most predominant fatty acid in all oils, accounting for 42-50%, of Derash and Yellow Dodolla oils, respectively, making Yellow Dodolla oil a super-high erucic acid oil. In comparison to the other oils, Yellow Dodolla was observed to be the least oxygenated oil, with a 7.80% oxygen content and oxygen to carbon ratio of 0.07, which may enable it to consume a very limited amount of hydrogen gas during hydrodeoxygenation in bio-jet fuel production. It was determined that, except for calcium and phosphorous levels in Tesfa, the concentrations of the metals and phosphorous were very small. Alkanes, alkenes, carboxylic acids, esters, alcohols, aromatics, and olefins were among the most significant and main functional groups identified. Our extraction and characterization results revealed that the Brassica carinata cultivars have very high oil contents, better physicochemical properties, excellent fatty acid profiles, and very low concentrations of heteroatoms (nitrogen, sulfur), metals and phosphorous concentrations, and very low level of oxygen to carbon ratios, making the oils, notably Yellow Dodolla oil, very high quality and promising alternative feedstocks for upgrading of the oils into bio-jet fuels through hydroprocessing pathway.

Unanswered issues on decarbonizing the aviation industry through the development of sustainable aviation fuel from microalgae

Concerns have been raised about the effects of fossil fuel combustion on global warming and climate change. Fuel consumer behavior is also heavily influenced by factors such as fluctuating fuel prices and the need for a consistent and reliable fuel supply. Microalgae fuel is gaining popularity in the aviation industry as a potential source of energy diversification. Microalgae can grow in saltwater or wastewater, capture CO2 from the atmosphere and produce lipids without requiring a large amount of land. As a result, the production of oil from microalgae poses no threat to food availability. The low carbon footprint of microalgae-derived fuels has the potential to mitigate the impact of traditional aviation fuels derived from petroleum on climate change and global warming. Therefore, aviation fuels derived from microalgae have the potential to be a more environmentally friendly and sustainable alternative to conventional fuels. Gathering microalgal species with a high lipid content, drying them, and turning them into aviation fuel is an expensive process. The use of biofuels derived from microalgae in the aviation industry is still in its infancy, but there is room for growth. This study analyses the potential routes already researched, their drawbacks in implementation, and the many different conceptual approaches that can be used to produce sustainable aviation fuel from microalgal lipids. Microalgae species with fast-growing rates require less space and generate lipids that can be converted into biofuel without imperiling food security. The key challenges in algal-based aviation biofuel include decreased lipid content, harvesting expenses, and drying procedure that should be enhanced and optimized to increase process viability.

Evaluation of Ukrainian Camelina sativa germplasm productivity and analysis of its amenability for efficient biodiesel production

Camelina or false flax ( Camelina sativa ) is an emerging crop that is currently considered one of the most promising feedstock for production of vegetable oil-based liquid biofuels: biodiesel and jet biofuel. Originally, camelina comes from the East European region, where this crop used to be widely cultivated before it was substituted with other oilseed crops, such as rapeseed, sunflower, etc. Due to increasing interest in biofuel production and sustainable agriculture, camelina has re-emerged as a viable oil-rich crop of multiple purposes. However, camelina varieties are not free from some undesirable traits, one of which is low yields. Over the recent years, extensive research efforts have been dedicated to breeding and improving this crop although this work has been restricted by limited genetic diversity of camelina. This limitation can be overcome by using unexploited germplasm, which previously was not involved into the camelina breeding process. In present study, we aimed to evaluate the productivity potential of unexploited Ukrainian spring camelina varieties and to perform comprehensive estimation of their suitability for use as oil feedstock for biodiesel production. The productivity data of all nine existing Ukrainian varieties of spring camelina was assessed for the 2001–19 period, based on the available data. It has been established that average productivity of the analyzed cultivars is 1756 kg/ha in the Ukrainian Forest-Steppe zone and 1146 kg/ha in the Steppe zone. The latter is characterized by a dryer climate, which significantly impacts spring camelina seed yields and thus their oil outputs, which are crucial for biofuel production. Potential rates of FAME- and FAEE-based biodiesel production have been evaluated. The conducted comprehensive analysis suggests that cultivation of spring camelina for biofuel production purposes can be more sustainable and feasible in the Forest-Steppe zone, rather than in the Steppe zone. Finally, a brief investigation of potential obstacles, impacting the production efficiency and feasibility of different biodiesel types, has also been conducted, as well as potential solutions were proposed for them. The obtained results create strong background for further efficient camelina breeding and for analyses of techno-economic feasibility of production camelina-based biofuels in Eastern Europe and specifically in Ukraine. • Performance of unexploited Ukrainian camelina germplasm was first evaluated. • Productivity of Ukrainian varieties of camelina was assessed for the 2001–19 period. • The average camelina yields were 1.76 t/ha in Forest-Steppe and 1.15 t/ha in Steppe. • Camelina oil yields depends more on seed yield, rather than seed oil content. • Biodiesel production rates were 726.53 and 374.96 L/ha in Forest-Steppe and Steppe.

Refining lipid for aviation biofuel at the molecular level

For improving aviation biofuel in quantity and quality, main precursor compounds have been investigated on the hydrotreating mechanism, including triglycerides by lipid extraction, fatty acid methyl/ethyl esters by transesterification, and fatty acids by hydrothermal liquefaction. Hydrotreating tests have been conducted on the effects of temperature, pressure, catalyst loading, and reaction time at molecular level. Fatty acid methyl/ethyl esters are the most desirable hydrotreating compounds for their highest biofuel yield and mildest upgrading conditions(≥290 °C, ≥10% catalyst loading). At the proper conditions of 290 °C and 30% catalyst loading, methyl stearate can yield 61.6% biofuel with 100% selectivity to alkanes. Fatty acids are the most difficult compounds to upgrade and should be hydrotreated above 310 °C and at least 30% catalyst loading, otherwise there are unconverted fatty acids, fatty aldehydes and fatty alcohols in the products. C30+ heavy esters are commonly found in the undesirable products and suppose to be derived from esterification of fatty acids and fatty alcohols under low temperature. Enhancing carbon number and unsaturation of the precursors promote the generation of olefins and oxygenates.

Catalytic hydroprocessing of waste cooking oil for the production of drop-in aviation fuel and optimization for improving jet biofuel quality in a fixed bed reactor

Waste cooking oil (WCO) is a bio-waste with significant potential for developing improved transportation fuel, specifically for the aviation industry. This work investigates the catalytic hydrocracking of WCO over commercial hydrocracking catalyst (Ni-Mo/silica-alumina) in a continuous flow fixed bed reactor to produce jet range hydrocarbons (HCs). The aim was to convert WCO into sustainable aviation and automotive fuel to get the maximum benefit from waste oil with high selectivity towards paraffins, naphthenes, minimal aromatics, and high isomerization (isomer to normal (i/n) ratio) in a single-step process using a single catalyst composition. The higher i/n ratio boosts specific energy, thermal stability and provides a low freezing point to the fuel. The results show that WCO conversion of 96.6 % with 55.6 % selectivity of jet range HCs was obtained at 420 °C temperature, 1 h−1 LHSV, 10 MPa pressure, and 2200 NLgas/Lliquid H2/oil ratio. In addition, isomer yield of 82.9 %, i/n ratio of 4.8, and selectivity of kerosene range HCs based on paraffins (43.6 %), naphthenes (8.2 %), and aromatics (3.73 %) was obtained at optimum reaction conditions. After hydroprocessing, the major fraction of heteroatoms (N = 99.9 %, S = 94.3 %, O = 99.9 %) was removed from WCO. Finally, the time on stream (TOS) study showed no deactivation of the catalyst up to 590 h, indicating the long life and stability of the catalyst, which is one of the highest lifetimes reported so far. Bio-jet fuel properties were tested according to the ASTM D-1655 standard. This research will aid in developing novel catalysts for the selective conversion of WCO into jet range HCs in a single step process.

Emission Factors of CO2 and Airborne Pollutants and Toxicological Potency of Biofuels for Airplane Transport: A Preliminary Assessment.

Aviation is one of the sectors affecting climate change, and concerns have been raised over the increase in the number of flights all over the world. To reduce the climate impact, efforts have been dedicated to introducing biofuel blends as alternatives to fossil fuels. Here, we report environmentally relevant data on the emission factors of biofuel/fossil fuel blends (from 13 to 17% v/v). Moreover, in vitro direct exposure of human bronchial epithelial cells to the emissions was studied to determine their potential intrinsic hazard and to outline relevant lung doses. The results show that the tested biofuel blends do not reduce the emissions of particles and other chemical species compared to the fossil fuel. The blends do reduce the elemental carbon (less than 40%) and total volatile organic compounds (less than 30%) compared to fossil fuel emissions. The toxicological outcomes show an increase in oxidative cellular response after only 40 min of exposure, with biofuels causing a lower response compared to fossil fuels, and lung-deposited doses show differences among the fuels tested. The data reported provide evidence of the possibility to reduce the climate impact of the aviation sector and contribute to the risk assessment of biofuels for aviation.

Investigation of Combustion of the Gas Turbine Engine from Kerosene and Biokerosene and Their Soot Characteristics in Diffusion Flames.

Performances, emissions from the gas turbine engine, and soot formations in diffusion flames of kerosene (Jet A1) and its mixture with 5% by volume bioparaffins (known as BK-5) are reported in the present study. A Rover 1S/60 gas turbine engine was used for recording performance parameters and emissions. Soot characteristics were investigated in smoke-free coannular wick-fed diffusion flames. This study is the next step that must be performed in the certification process of a new aviation biofuel before it is tested in the aircraft. The results show that BK-5 produced a similar performance against Jet A1. Throughout the whole power range under investigation, BK-5 emitted 3.4% NOx higher than Jet A1, while Jet A1 released CO and HC at the rates that are, respectively, 1.8 and 4.5% greater than its counterpart. The soot emissions from the BK-5 and Jet A1 were comparable across the measured flame height range. The results encouraged future studies to carry out the modern engine and flight tests. The production process for bioparaffins employed in this work has been demonstrated to be viable and appropriate for tropical developing nations. The current process should also continue to be improved by eliminating high-distillation temperature components in bioparaffins.

Solvent-free dehydration, cyclization, and hydrogenation of linalool with a dual heterogeneous catalyst system to generate a high-performance sustainable aviation fuel

The development of efficient catalytic methods for the synthesis of bio-based, full-performance jet fuels is critical for limiting the impacts of climate change while enabling a thriving modern society. To help address this need, here, linalool, a terpene alcohol that can be produced via fermentation of biomass sugars, was dehydrated, cyclized, and hydrogenated in a one-pot reaction under moderate reaction conditions. This sequence produced a biosynthetic fuel mixture primarily composed of 1-methyl-4-isopropylcyclohexane (p-menthane) and 2,6-dimethyloctane (DMO). The reaction was promoted by a catalyst composed of commercial Amberlyst-15, H+ form, and 10% Pd/C. Two other terpenoid substrates (1,8-cineole and 1,4-cineole) were subjected to the same conditions and excellent conversion to high purity p-menthane was observed. The fuel mixture derived from linalool exhibits a 1.7% higher gravimetric heat of combustion and 66% lower kinematic viscosity at −20 °C compared to the limits for conventional jet fuel. These properties suggest that isomerized hydrogenated linalool (IHL) can be blended with conventional jet fuel or synthetic paraffinic kerosenes to deliver high-performance sustainable aviation fuels for commercial and military applications.

Converting polyisoprene rubbers into bio-jet fuels via a cascade hydropyrolysis and vapor-phase hydrogenation process

Producing alternative drop-in bio-jet fuels from biomass provides a promising approach to achieve carbon neutrality. To upcycle biomass-based polyisoprene rubbers into jet-fuel range C10 cycloalkane, we proposed a cascade hydropyrolysis and vapor-phase hydrogenation process in a flow-through two-stage pressurized fixed-bed reactor. The hydropyrolysis temperature in the first stage is of vital importance for the formation of primary limonene intermediate in the non-catalytic degradation of polyisoprene rubbers, and a reaction temperature of 460 °C maximized limonene yield to 588.6 mg/g for natural rubber and 546.2 mg/g for Eucommia rubber. Over a Pt/C catalyst loaded in the second stage, the limonene intermediate produced from the first-stage reactor can be completely hydrogenated, giving a 642.7 mg/g yield of jet-fuel range C10 cycloalkane with 83.6% selectivity. The depolymerization mechanism of polyisoprene rubbers was thoroughly studied, and a competitive reaction between limonene hydrogenation and limonene dehydrogenation was observed. This is the first report on producing C10 cycloalkane from natural rubbers via a cascade hydropyrolysis and hydrogenation process, providing a promising strategy to upcycle polyisoprene rubbers into bio-jet fuels.

Analysis of induced land use change by the production of aviation biofuels in Brazil

Analysis of induced land use change by the production of aviation biofuels in Brazil

Environmental and economic issues for renewable production of bio-jet fuel: A global prospective

Given how quickly the aviation sector is growing, it is crucial to find sustainable ways to supply the demand. Modern technological developments and the creation of alternative jet fuels are crucial elements that could help eliminate greenhouse gases (GHGs) like CO2 emissions. Traditional jet fuel produces a sizable amount of GHG emissions, which has raised concern on a global scale. Compared to conventional jet fuel, biofuel is thought to be more renewable and less polluting. Biojet fuels might work as an effective substitute. The varieties of bio jet fuel, manufacturing procedures (including alcohol-to-jet, oil-to-jet, syngas-to-jet, and sugar-to-jet ways), existing regulations, and the effects of bio jet fuels on the environment and the economy are all covered in length in this overview. These are the techniques that are most frequently used to create bio-jet fuel from both edible and inedible feedstock. The main conclusions of this review indicate that the most popular method for producing biofuel is hydrogenated esters and fatty acids (HEFA). The Fischer-Tropsch (FT) approaches cost more to install even though they produce fewer GHGs. Environmentally beneficial and technologically advanced, second-generation biofuels are a great choice. It has been revealed that jatropha is a crop that produces a lot of energy. The price of feedstock and the lack of bio-jet fuel are the two biggest obstacles to substituting conventional fuel. To increase the power and quality of energy, further in-depth research on optimal feedstocks is necessary. In order to address the needs of both commercial and military aircraft, biomass jet fuel has a lot of potential to replace conventional jet fuel. High yield should be one of the properties of the feedstock without affecting food production.

Porous Biochar Supported Transition Metal Phosphide Catalysts for Hydrocracking of Palm Oil to Bio-Jet Fuel.

The upgrading of plant-based oils to liquid transportation fuels through the hydrotreating process has become the most attractive and promising technical pathway for producing biofuels. This work produced bio-jet fuel (C9–C14 hydrocarbons) from palm olein oil through hydrocracking over varied metal phosphide supported on porous biochar catalysts. Relative metal phosphide catalysts were investigated for the highest performance for bio-jet fuel production. The palm oil’s fiber-derived porous biochar (PFC) revealed its high potential as a catalyst supporter. A series of PFC-supported cobalt, nickel, iron, and molybdenum metal phosphides (Co-P/PFC, Ni-P/PFC, Fe-P/PFC, and Mo-P/PFC) catalysts with a metal-loading content of 10 wt.% were synthesized by wet-impregnation and a reduction process. The performance of the prepared catalysts was tested for palm oil hydrocracking in a trickle-bed continuous flow reactor under fixed conditions; a reaction temperature of 420 °C, LHSV of 1 h−1, and H2 pressure of 50 bar was found. The Fe-P/PFC catalyst represented the highest hydrocracking performance based on 100% conversion with 94.6% bio-jet selectivity due to its higher active phase dispersion along with high acidity, which is higher than other synthesized catalysts. Moreover, the Fe-P/PFC catalyst was found to be the most selective to C9 (35.4%) and C10 (37.6%) hydrocarbons.

Investigation of the Durability of Gaskets in Contact with Bio- and Aviation Fuels.

Care for the natural environment, which can be observed in the tightening of emission standards, has enforced the search for new fuels, especially renewable sources of natural origin. The article presents the results of theoretical and experimental considerations on the impact of aviation biofuels on the materials used for sealing flange joints. The fuel type selected for the test is compatible with aviation fuels. Fuels have been enriched with a bio-additive that changes the technical and physical properties of the fuel. The tested gaskets were made of soft, aramid-elastomeric materials that were flat in shape and without reinforcement. Their commercial names are AFO and AFM. Tests were carried out with the use of a simple flange joint with a fuel reservoir at 373 K. Both fuel loss and the pressure drop on the gasket were measured during a 1000 h period of time. The experiments showed that the seals preserved the technical parameters in the presence of the tested fuels. The fuel loss did not exceed the accepted limits, which demonstrates the suitability of the tested materials for utilization with new types of fuel. However, no unequivocal conclusions can be drawn about the positive or negative impact of bio-additives on the sealing material due to the fact that both an improvement and deterioration in tightness under certain circumstances were observed. Based on the experimental data, a mathematical model was proposed that makes it possible to predict the service life of the gaskets in flange joints in contact with the investigated types of fuel. The potential application of the research results is practical information about the impact of biofuel on the gasket, and hence the information about the possibility of using traditional sealing materials in a new application—for sealing installations for the production, transmission and storage of biofuels.

Rubber seed oil: Potential feedstock for aviation biofuel production

The aviation industry is responsible for 12% of transport-related GHG emissions and 2–3% of the global GHG emissions, thus raising concerns for sustainable alternatives such as aviation biofuels. This study sought to analyze the potential of producing aviation fuel from rubber seed oil. Rubber seed oil (RSO) was extracted and the physicochemical properties investigated as well as the fatty acid composition. This result was simulated in ASPEN plus to determine the potential aviation biofuel produced using the UOP HEFA process. The study shows that the golden yellowish oil derived from rubber seed possessed a density 0.9 g/cm3 and pH of 6, refractive index of 1.48, heating value of 23.75 MJ/kg and composed of 75% area of FFA with Oleic and Linoleic acid been the most dominant. The HEFA process on ASPEN Plus showed 81% of feedstock was converted to hydrocarbons with aviation biofuel yield of 46%. It was estimated that the installation of the plant for aviation biofuel production has a total capital cost of $ 8,650,480 and a total operation cost of $ 328,728. The economic analysis shows that at a cost of USD 4/kg (USD 3.01/liter) of aviation biofuel has an Internal rate of return of 18.62% profitability of 1.18 and payback period of 14.9 years of the plant operating. This study established that rubber seed oil shows suitability and potential for sustainable aviation biofuel production.