Renewable Jet Research Articles

Carbon-Based Solid Acids for the Preparation of Renewable Jet Fuel and Diesel Range Alkanes

Carbon-Based Solid Acids for the Preparation of Renewable Jet Fuel and Diesel Range Alkanes

Scaling a bifunctional catalytic Fixed-Bed reactor for acetone-to-mesitylene Jet-Fuel additive production

De-fossilization of the aviation sector will require the use of renewable synthetic jet fuels and additives that comply with strict regulations. One such additive, mesitylene, can be produced using a novel sustainable process based on the fermentation of biomass waste to acetone, followed by the self-condensation of acetone to mesitylene. This study addresses the viability of gas-phase self-condensation of acetone, catalyzed by TiO2 and Al-MCM-41 acid catalysts, at a technological readiness level of TRL-4.The reactor used was a bench-scale fixed-bed reactor (28 mm diameter and 500 mm height) loaded with commercial-sized catalyst pellets (1/8″ diameter). It was equipped with a jacket for heat transfer using flowing thermal oil. The performance of commercial-scale reactors was approximated under conditions of 275 °C, 280 kPa, and a space velocity of 50–500 mol/kg·h.The catalyst pellets exhibited significant mass transfer resistances, which limited the reaction rate. This, in turn, reduced the deactivation rate caused by the adsorption of high-molecular-weight condensation products on the strongest acid sites. Additionally, the product distribution differed between pellet and powder forms of the catalysts, with higher yields of isophorone and mesitylene being observed on TiO2 and Al-MCM-41 pellets, respectively. A reaction and mass transfer model was proposed and fitted to the bench-scale data.The study also considered the combination of both catalyst pellets in the same reactor for the bench-scale unit. It was demonstrated that mesitylene yield could be improved, with the best configuration being two separate beds placed consecutively in the reactor with a catalyst ratio of 1:2 (TiO2:MCM-41).

Sustainable Aviation Fuel Production through Catalytic Processing of Lignocellulosic Biomass Residues: A Perspective

Currently, the transportation sector represents about one third of the total energy consumed in the world, most of this energy being obtained almost exclusively from oil. However, the world is changing, as well as the aviation industry. Since lignocellulosic biomass is a low-cost feedstock that does not compete with food, it has drawn great attention as one of the most attractive alternatives to replace fossil feedstocks for the production of fuels. Renewable jet fuels could have a significant impact on lowering greenhouse gas emissions and providing a long-term sustainable alternative to petroleum-derived fuels. However, the catalytic upgrading of lignocellulosic residues in industry still remains a big challenge and the development of highly integrated systems that allow the direct conversion of lignocellulosic wastes is essential to achieve that goal. The importance of renewable jet fuels and the potential of lignocellulosic biomass have already been extensively reviewed. However, this work presents a new perspective on the main catalytic routes and challenges for the sustainable production of aviation fuels from biomass wastes.

Hydrodeoxygenation of isoeugenol in continuous mode using bifunctional Pt-Beta 25-binder catalysts for renewable jet fuel production

Hydrodeoxygenation of isoeugenol in a trickle-bed reactor yielded propylcyclohexane, a jet fuel compound. The effect of metal location, acidity, and particle size were evaluated for platinum-based extruded catalysts (Pt, Beta-25, binder).

Designing a Renewable Jet Fuel Supply Chain: Leveraging Incentive Policies to Drive Commercialization and Sustainability

Renewable jet fuel (RJF) production has been recognized as a promising approach for reducing the aviation sector’s carbon footprint. Over the last decade, the commercial production of RJF has piqued the interest of airlines and governments around the world. However, RJF production can be challenging due to its dispersed supply resources. Furthermore, the production of RJF is more costly compared to producing conventional jet fuel. In this study, using a mixed integer linear programming (MILP), we design a corn-stover-based RJF supply chain network in which we obtain an optimized configuration of the supply chain and determine operational decisions required to meet RJF demand at airports. To accelerate the commercialization of RJF production, we examined four incentive programs designed to cover the supply chain’s costs, with agricultural statistics districts serving as the designated supply regions. This study is validated by employing the model to design the supply chain in the Midwestern United States. The results from this study are promising as they show the supply chain can achieve commercialization with partial financial coverage from the incentive programs. Based on the findings of this study, policymakers can devise policies to commercialize RJF production and accelerate its adoption by the industry.

Limitations to sustainable renewable jet fuels production attributed to cost than energy-water-food resource availability

Renewable jet fuel (RJF) is often touted as the only viable sustainable energy source for the aviation sector, given the difficulties faced by other low-carbon energy sources in overcoming technological barriers. Despite that, the sustainability of RJF is still in dispute due to the conflicting requirements in natural resource for producing the fuels. We introduce a holistic 25-indicator sustainability index encompassing the four domains of energy-water-food nexus and governance, that measures the potential impact of RJF production on 154 countries (and territories) through the oil-to-jet, alcohol-to-jet and gas-to-jet conversion methods. Countries and territories are ranked according to the composite index scores of the four domains. The sustainability index model provides insights on how RJF affords the aviation sector a clean slate in determining the manner of development in a sustainably and equitable way, while also marching towards the long-term goal of carbon neutrality, in alignment with the Sustainable Development Goals.

Bifunctional Pt Catalysts Supported on a Zeolite-Binder Matrix for the Hydrodeoxygenation of Isoeugenol for Renewable Jet Fuel Production

Hydrodeoxygenation (HDO) of isoeugenol was carried out at 200 °C and 30 bar of H2 in a batch reactor using a series of bifunctional catalysts consisting of platinum supported on zeolite H-Beta-25 or H-Beta-300 and Bindzil as a binder. The purpose of the matrix was to understand the effect of the binder on the reaction, emulating the components of industrial catalysts and therefore facilitating catalyst scale-up. The effect of the supports acid strength, the location of metal nanoparticles, and their proximity to acid sites was also studied. The catalysts were characterized by N2 physisorption, inductively coupled plasma atomic emission spectrometry, Fourier transform infrared spectroscopy of adsorbed pyridine and scanning and transmission electron microscopy. It was found that platinum supported only on the zeolite was more active compared to platinum located on the binder. High levels of isoeugenol conversion (ca. 100%), propylcyclohexane yield (56%) and the liquid-phase mass balance (68%) were obtained for the catalyst consisting of Pt supported on both zeolite H-Beta-25 and Bindzil.

4-Hydroxybenzyl alcohol from Sinapis alba mustard seed meal extract for control of liverwort (Marchantia polymorpha)

Sinapis alba mustard seed meal extract is a by-product of mustard oil extraction, that is used for biodiesel and renewable jet fuel production. Recently, S. alba mustard seed meal has been shown to have herbicidal activity for a range of problematic weeds. The objectives of the present research were 1) to optimize the preparation of S. alba mustard seed meal extract; 2) to explore the applicability of S. alba mustard seed meal extract for control of liverwort, a common pest in ornamental plants greenhouses; and 3) to identify the major herbicidal compound(s) in these extracts. For extraction, methanol content in aqueous solution was optimized between 0% and 100%. Extracts prepared with 0–30% aqueous methanol provided 98–100% control of liverwort after single application and prevented liverwort plants from recovering. Extracts prepared using sequential extraction with 60% methanol provided an additional benefit of low particulate solutions. The efficiency of the produced S. alba mustard seed meal extract was comparable to two commercially available herbicides labeled for liverwort control under greenhouse conditions. Composition of S. alba mustard seed meal extracts was analyzed by high-performance liquid chromatography mass spectrometry and ion chromatography. 4-Hydroxybenzyl alcohol was identified as a main herbicidal compound based on the analysis and using commercially available reference solution. To the best of our knowledge, this is the first report of 4-hydroxybenzyl alcohol herbicidal activity toward nonvascular plants. The high concentrations of 4-hydroxybenzyl alcohol naturally produced from S. alba mustard seed meal, makes it a potential herbicide feedstock material.

Hydrodeoxygenation of safflower oil over cobalt-doped metal oxide catalysts for bio-aviation fuel production

The catalytic hydrodeoxygenation process provides an alternative route for the production of renewable jet fuel, which can directly replace petroleum-derived hydrocarbons. To this end, the catalytic performance of Co-based catalysts supported by different metal oxides, γ-Al2O3, TiO2, ZnO and ZrO2 was tested to evaluate their catalytic activity and product selectivity in hydrodeoxygenation of safflower oil. The results indicated that catalytic performance changed in response to acidity, morphologies and particle size of catalysts. Benefiting from these combined characteristics, Co/ZnO catalyst exhibited a highly catalytic activity, being capable of producing jet fuel-range hydrocarbon selectivity of 65.96% under reaction parameters of 350 °C of reaction temperature, 8 h of reaction time and 75 bar of H2 initial pressure. In addition to superior activity, the coke content of Co/ZnO was much lower compared to other employed catalysts thereby affecting the stability of the catalyst and resulting in less deactivation and coke formation.

Synthesis of renewable diesel and jet fuels from bio-based furanics via hydroxyalkylation/alkylation (HAA) over SO42-/TiO2 and hydrodeoxygenation (HDO) reactions

Upgrading biomass to renewable diesel and jet fuels is essential to achieve carbon neutrality. Herein, diesel and jet fuels range alkanes were produced by HAA of 2-methylfuran and furfural over solid acid SO42-/TiO2 and subsequent HDO over Pd/NbOPO4. A series of SO42-/TiO2 catalysts were synthesized by wetness impregnation to produce C15 fuel precursors. S/Ti-450 with a calcination temperature of 450 °C exhibited the highest activity, affording 97.9 % yield of C15 fuel precursor. Sufficient Brønsted acid sites and moderate Brønsted acid strength are responsible for the super catalytic performance of S/Ti-450. Stability studies demonstrated that S/Ti-450 could be regenerated. Furthermore, the application of S/Ti-450 in the HAA reaction was extended to other carbonyl compounds (e.g., butanal, cyclohexanone and acetone) and high yields of desired fuel precursors were obtained. Finally, C15 fuel precursor was further converted to long-chain alkanes via HDO over Pd/NbOPO4, yielding 85.0 % diesel and jet fuels range alkanes.

The combustion performance of sustainable aviation fuel with hydrogen addition

Hydrogen (H2) aircraft have been proposed for the “Fly Net Zero” target. The combination of jet fuel and H2 was offered to successfully operate the jet engine with H2 without further combustor modification. The current work used hydro-processed renewable jet fuel (HRJ) and experimentally investigated its combustion properties and H2 addition in the constant volume combustion chamber (CVCC). Experiments were performed at the initial temperature (Tini) from 600 K to 818 K, initial pressure (Pini) 10, 15 bar and equivalence ratio (φ) = 0.5. Normal spray ignition (SPI) and direct injection spark ignition (DISI) were studied. Overall, HRJ has a shorter ignition delay (ID) for SPI. At 600 K, adding 10% and 20% H2 to HRJ increased ID to 12.68% and 38.46%, respectively. As Tini rose to 725 K, increment in ID was shortened to 5.96% and 20.47% with 10% and 20% H2 addition, respectively. For DISI, at 600 K, adding 10% and 20% H2 to HRJ shortens ID to 3.56% and 4.92%, respectively. When comparing the ID of DISI with the SPI, ID was shortened to 84.64% and 91.77% for 10% and 20% H2 addition, respectively. Emission results showed that adding H2 reduced CO2, while NOx emissions were increased. Ansys Chemkin-Pro was used to run numerical simulations of a zero-dimensional (0-D) closed homogeneous batch reactor model (CHBR). An existing HRJ mechanism was adopted, and H2 elementary reaction rate constant factors were updated for better model predictions. The updated model was under prediction with the experimental ID periods. The simulation results showed that the reaction H2+OH = H + H2O is the primary cause for consuming OH radicals with H2 addition, leading to an increase in fuel ID. At higher temperatures, two major reactions (HO2 + H2 = H2O2 + H, and HO2+HO2 = H2O2 + O2) followed by H2O2 = OH + OH are accountable for reproducing OH radicals. Thus, the fuel ID was shorter.

Are there synergies in the decarbonization of aviation and shipping? An integrated perspective for the case of Brazil

SummaryAviation and shipping account for 22% of total transport-related CO2 emissions. Low-carbon fuels (such as biofuels and e-fuels) are the most promising alternatives to deeply decarbonize air and maritime transport. A number of technological routes focused on the production of renewable jet fuel can coproduce marine fuels, emulating the economies of scope of crude oil refineries. This work aims to investigate possible synergies in the decarbonization of aviation and shipping in Brazil, selected as an interesting case study. An Integrated Assessment Model (IAM) of national scope is used to explore different combinations of sectoral and national climate targets. This IAM represents not only the energy supply and transport systems but also the agricultural and land-use systems. In the absence of a deep mitigation policy for Brazil, results indicate synergies related to oilseed- and lignocellulosic-based biofuels production routes. Imposing a strict carbon budget to the Brazilian economy compatible with a world well below 2°C, the portfolio of aviation and shipping fuels changes significantly with the need for carbon dioxide removal strategies based on bioenergy. In such a scenario, synergies between the two sectors still exist, but most renewable marine energy supply is a by-product of synthetic diesel produced for road transport, revealing a synergy different from the one originally investigated by this work.

Energy, economic and environmental (3E) analysis for the renewable jet fuel production process

Blending conventional petroleum jet fuel with renewable fuel obtained from hydro-processing of cooking oil wastes can significantly reduce the carbon footprint of the aviation sector. Renewable jet fuel (RJF) remains for the most part more expensive than conventional jet fuel and the life-cycle emissions reduction depends on the feedstock. For promoting mass production of used cooking oil (UCO) based jet fuel, a 3E (energy/exergy, environmental and economic) analysis of a simulated processing plant is carried out. Hydrogen is the main component in the two-step process: hydro-processing and hydro-cracking/isomerization. Hydrogen production and exergy destruction in the process significantly influence the life-cycle emissions of the RJF. The low exergy efficiency of the process units where significant heat transfer occurs generates an increase in the price of the products. Results show a life-cycle carbon dioxide emissions reduction from 41 % to 81 % when combusting the hydro-processed jet fuel instead of conventional jet fuel. The minimum fuel selling price could be very close to conventional jet fuel (about 18 % more expensive) if an effective cooking oil wastes collection system is in place. Moreover, when implementing a carbon tax above $37/tCO 2 the price becomes equal to conventional jet fuel. UCO is the most sustainable feedstock as there is no competition with the food market and the environmental benefits justify government spending for promoting mass production.

Renewable Aviation Fuel: Review of Bio-jet Fuel for Aviation Industry

The search for environmentally sound, socially responsible, and economically viable renewable fuel generation methods is a major global concern. A type of aviation fuel called jet fuel or often spelled avtur is intended for use in aeroplanes with turbine (gas) engines. Jet fuel appears colourless. The fuels Jet A and Jet A-1 are the most frequently used ones in commercial aviation sector. Other than Jet B, which is utilised for its enhanced cold-weather operation, there are no other jet fuels that are frequently used in gas-turbine-engine in the aviation industry. Renewable aviation fuel or known as bio-jet fuels represent a sizable sector for the consumption of fossil fuels. The production of bioethanol and biodiesel for piston engine vehicles in internal combustion engines has already shown that biofuel can play a significant role in the development of sustainable renewable aviation jet fuel. Here, we also provide a book review on the potential bio-jet fuel as a renewable aviation jet fuel.

The study of combustion characteristics for conventional and renewable Jet fuels at Low-to-intermediate temperatures in a rapid compression Machine

The combustion characteristics of jet fuels, including conventional (Jet-A1 and JP-5) and renewable (hydro-processed renewable jet, HRJ) jet fuels at low-to-intermediate temperatures were studied in a rapid compression machine (RCM). Compression pressures were varied at 10, 15, and 20 bar under a low temperature combustion regime (626 K-874 K). Fuel/oxidizer mixture conditions were created in order to investigate the auto-ignition delays responding to various equivalence ratios of 0.25 and 0.5. Longer auto-ignition delays were observed with a leaner fuel/oxidizer mixture (ϕ=0.25) by as much as 79.2% as compared to the richer mixture condition (ϕ=0.5). Doubling the compression pressures from 10 to 20 bar led to the reduction of the auto-ignition delays by as much as 58.8%. The negative temperature coefficient (NTC) regime was found to be strongly related to the changes in the equivalence ratio, where the NTC formation is clearly observed at lower equivalence ratio of 0.25 for all the tested fuels. In addition, the renewable jet fuel exhibited a shorter auto-ignition delay by as much as 54.5% as compared to Jet-A1 and JP-5 at equivalence ratio of 0.5. The higher hydrogen-to-carbon (H/C) ratio and lower concentration of cyclic molecules in the HRJ were among the reasons for the reactivity improvement compared to the petroleum jet fuels.

Bifunctional Pt–Re Catalysts in Hydrodeoxygenation of Isoeugenol as a Model Compound for Renewable Jet Fuel Production

Bifunctional Pt–Re Catalysts in Hydrodeoxygenation of Isoeugenol as a Model Compound for Renewable Jet Fuel Production

Economic optimization for a dual‐feedstock lignocellulosic‐based sustainable biofuel supply chain considering greenhouse gas emission and soil carbon stock

AbstractEnvironmental factors, including greenhouse gas (GHG) emissions and soil organic carbon (SOC), should be considered when building a sustainable biofuel supply chain. This work developed a three‐step optimization approach integrating a geographical information system‐based mixed‐integer linear programming model to economically optimize the biofuel supply chain on the premise of meeting certain GHG emission criteria. The biomass supply grid cell was considered first, based on a maximum level of GHG emissions, prior to economic optimization. The optimization simultaneously considered dual‐feedstock sourcing, selection between distributed and centralized configurations, and the impact of maintaining SOC balance in agricultural soil on biomass availability. The applicability of the modeling approach was demonstrated through a case study that optimized a dual‐feedstock renewable jet fuel supply chain via a gasification‐Fischer–Tropsch (gasification‐FT) conversion pathway in 2050 under three biomass availability scenarios. The case study results show that the differences in procurement costs and GHG emissions between energy crops and agricultural residues have a large impact on the layout of the supply chain. The supply‐chain configuration tends to be more centralized with large‐scale biorefineries when a supply region has an intensive and centralized distribution of biomass resources. The cost‐supply curves demonstrated the technical potential of biofuels that could be obtained at a certain level of cost. Additionally, sensitivity analysis shows that the GHG emission credit from producing extra electricity during the gasification‐FT process will be significantly reduced with a rising share of renewable electricity generation in the future. © 2022 The Authors. Biofuels, Bioproducts and Biorefining published by Society of Industrial Chemistry and John Wiley & Sons Ltd.

Controllably produce renewable jet fuel with high-density and low-freezing points from lignocellulose-derived cyclopentanone

Production of jet fuel with high performance is attractive in the field of biomass utilization. This paper provides a way to controllably produce renewable jet fuel with high-density and low-freezing point by the condensation of biomass-derived cyclopentanone and followed hydrodeoxygenation. It is found that the freezing point of the jet fuel decreased rapidly with the increase of the content of spirocyclic alkane and the density increased gradually with content of tricyclic alkane. And the composition of jet fuel can be adjusted by controlling the reaction conditions of cyclopentanone condensation. At 30 °C and 3 h, the precursors of jet fuel were prepared by condensation of cyclopentanone over NaOH catalyst and the final obtained HDO products were comprised of 54.56% bicyclopentane, 31.88% tricyclic alkane and 13.56% spirocyclic alkane. The density of the jet fuel was 0.869 g·ml−1 and the freezing point was less than −60 °C. These parameters are obviously superior to that of commercial Jet-A.

Economic and Environmental Potential of Large-Scale Renewable Synthetic Jet Fuel Production through Integration into a Biomass CHP Plant in Sweden

The potential of bio-electro-jet fuel (BEJF) production with integration into an existing biomass-based combined heat and power (CHP) facility was investigated. The BEJF is produced via Fischer–Tropsch (F–T) synthesis from biogenic CO2 and H2 obtained by water electrolysis. Techno-economic (TEA)- and life. cycle (LCA)- assessments were performed to evaluate the production cost and environmental impact of the BEJF production route. The BEJF mass fraction reached 40% of the total F–T crude produced. A reduction of 78% in heating demands was achieved through energy integration, leading to an increase in the thermal efficiency by up to 39%, based on the F–T crude. The total production cost of BEJF was in the range of EUR 1.6–2.5/liter (EUR 169–250/MWh). The GWP of the BEJF was estimated to be 19 g CO2-eq per MJ BEJF. The reduction potential in GWP in contrast to the fossil jet baseline fuel varied from 44% to more than 86%. The findings of this study underline the potential of BEJF as a resource-efficient, cost-effective, and environmentally benign alternative for the aviation sector. The outcome is expected to be applicable to different geographical locations or industrial networks when the identified influencing factors are met.

Renewable jet fuel supply chain network design: Application of direct monetary incentives

Currently, the global aviation industry uses around 341 billion liters of jet fuel per year, with demand predicted to grow by 50% by the end of 2050. Renewable jet fuel (RJF) may cut greenhouse gas emissions (GHG), increase fuel diversity for the aviation industry, and promote rural economies. The commercialization of RJF has been delayed due to a shortage of sustainable biomass resources. This study recommends using winter carinata crops as a reliable biomass feedstock in the southeastern US states, where the availability of resources will be investigated in each agricultural zone. RJF production is more expensive than traditional jet fuel production. Investors and legislators need to learn more about prospective federal financial initiatives, such as subsidies and grants, to help with RJF supply chain implementation. In this paper, using a mathematical programming approach, we designed an RJF supply chain and then investigated the effects of three direct monetary incentive programs, including producer credit program (PCP), biomass crop assistance program (BCAP), and biorefinery assistance program (BAP), to accelerate the commercialization of RJF manufacturing. According to the findings, the amount of incentives through PCP needed to fulfill 50% of the RJF demand was assessed to cover 16.70% of the total costs, while the BCAP could reach the commercialization threshold by receiving incentives for 22.84% of the biomass purchasing cost. Furthermore, having the BAP covering 89.39% of the annual capital and operating costs could help commercialize RJF production. This study also evaluated the effects of changes in renewable fuel prices, demand fulfillment rates, biomass yield rates, and the price of biomass feedstock and its resulting meal on the profitability of the supply chain. The study's findings will advise policymakers and investors on developing the RJF supply chain given various financial assistance programs and subsidies.