Techno-economic and resource analysis of hydroprocessed renewable jet fuel

Trends and emerging research directions of sustainable aviation: A bibliometric analysis

This study aims to conduct a bibliometric analysis to determine trends and emerging research directions of sustainable aviation between 2001 and 2023. 726 studies indexed in the Web of Science were examined through VOSviewer software. Science mapping and performance analyses were implemented to demonstrate a systematic quantitative review and the characteristics of the research area. Moreover, by using co-occurrence of keywords, citation, bibliographic coupling, co-authorship, and co-citation analyses, the trends of the research area were revealed in detail. Findings indicated that the publications on sustainable aviation literature were mainly conducted between 2020 and 2023. Research areas of the publications were mainly on "engineering" and "energy fuels". In terms of number of the publications, "International Journal of Sustainable Aviation Fuel" was the most productive source and Heyne was the most productive author. Co-occurrence analysis demonstrated that "sustainable aviation fuel" was the most frequently used keyword. Furthermore, sustainable aviation research has shifted in focus toward more challenging and technology-oriented research over time. Citation analysis indicated that the most cited author was Heyne, the most cited study was Ma et al.'s study on "Aviation biofuel from renewable resources: routes, opportunities and challenges" and the most cited sources was "Energy". Among countries, the U.S.A was the most cited country and Chinese Academy of Sciences was the most cited organization. Bibliographic analysis showed that Heyne was the author with the highest connection strength. Co-authorship analysis demonstrated that Washington State University was the most collaborative organization. Finally, co-citation analysis of cited references indicated that fundamental subjects and related references were mainly sustainable aviation fuel, production of sustainable aviation fuel and its use in aviation studies. It is anticipated that results of this study would contribute to sustainable aviation research and ensure guidance and new perspectives for future research topics and directions on sustainable aviation.

High-Resolution Lipidomics Reveals Influence of Biomass and Pretreatment Process on the Composition of Extracted Algae Oils As Feedstock for Sustainable Aviation Fuels

The increasing demand for sustainable aviation fuel (SAF) creates a need for innovative biomass and lipid sources with compositions that are compatible with refineries. Algae-derived oils present an opportunity to supply a process-compatible lipid feedstock at yields higher than those of conventional oilseed crops. With few documented reports on chemical composition, the process readiness remains elusive. We present data on extraction efficiency, yield, and purity of lipids from algae with and without the application of a low-concentration sulfuric acid pretreatment of the biomass. The pretreatment process increased the oil yield and positively impacted the quality of the extracted oils. Results from fatty acid and lipidomics analysis revealed that the low-lipid biomass sources extracted 70-80% of the available lipids, and the non-fatty acid co-extractants exceeded 40% of the extracted oils. For a high-lipid algae sample, derived from a genetically engineered strain, we show >90% extraction yield with >85% FAME purity. This work provides insights into the composition of algae-derived oils and quality metrics that are essential to determining the viability of lipid hydroprocessing to SAF.

The Genus Cuphea P. Browne as a Source of Biologically Active Phytochemicals for Pharmaceutical Application and Beyond—A Review

Cuphea P. Browne (Lythraceae) is a monophyletic taxon comprising some 240–260 species that grow wild in the warm, temperate, and tropical regions of South and Central America and the southern part of North America. They have been valued as traditional medicinal remedies for numerous indications, including treating wounds, parasitic infections, hypertension, digestive disorders, cough, rheumatism, and pain. Modern pharmacological research provides data that support many of these traditional uses. Such a wide array of medicinal applications may be due to the exceptionally rich phytochemical profile of these plants, which includes bioactive compounds classified into various metabolite groups, such as polyphenols, triterpenes, alkaloids, and coumarins. Furthermore, Cuphea seed oils, containing medium-chain fatty acids, are of increasing interest in various industries as potential substitutes for coconut and palm oils. This review aims to summarize the results of phytochemical and pharmacological studies on Cuphea plants, with a particular focus on the therapeutic potential and molecular mechanisms of the action of polyphenolic compounds (especially flavonoids and tannins), which have been the subject of many recently published articles.

Techno-economic analysis of an integrated biorefinery to convert poplar into jet fuel, xylitol, and formic acid

BACKGROUND

The overall goal of the present study is to investigate the economics of an integrated biorefinery converting hybrid poplar into jet fuel, xylitol, and formic acid. The process employs a combination of integrated biological, thermochemical, and electrochemical conversion pathways to convert the carbohydrates in poplar into jet fuel, xylitol, and formic acid production. The C5-sugars are converted into xylitol via hydrogenation. The C6-sugars are converted into jet fuel via fermentation into ethanol, followed by dehydration, oligomerization, and hydrogenation into jet fuel. CO₂ produced during fermentation is converted into formic acid via electrolysis, thus, avoiding emissions and improving the process's overall carbon conversion.

RESULTS

Three different biorefinery scales are considered: small, intermediate, and large, assuming feedstock supplies of 150, 250, and 760 dry ktonne of poplar/year, respectively. For the intermediate-scale biorefinery, a minimum jet fuel selling price of $3.13/gallon was obtained at a discount rate of 15%. In a favorable scenario where the xylitol price is 25% higher than its current market value, a jet fuel selling price of $0.64/gallon was obtained. Co-locating the biorefinery with a power plant reduces the jet fuel selling price from $3.13 to $1.03 per gallon.

CONCLUSION

A unique integrated biorefinery to produce jet fuel was successfully modeled. Analysis of the biorefinery scales shows that the minimum jet fuel selling price for profitability decreases with increasing biorefinery scale, and for all scales, the biorefinery presents favorable economics, leading to a minimum jet fuel selling price lower than the current price for sustainable aviation fuel (SAF). The amount of xylitol and formic produced in a large-scale facility corresponds to 43% and 25%, respectively, of the global market volume of these products. These volumes will saturate the markets, making them infeasible scenarios. In contrast, the small and intermediate-scale biorefineries have product volumes that would not saturate current markets, does not present a feedstock availability problem, and produce jet fuel at a favorable price given the current SAF policy support. It is shown that the price of co-products greatly influences the minimum selling price of jet fuel, and co-location can further reduce the price of jet fuel.

Production of Jet Biofuels by Catalytic Hydroprocessing of Esters and Fatty Acids: A Review

The transition from fossil to bio-based fuels is a requisite for reducing CO2 emissions in the aviation sector. Jet biofuels are alternative aviation fuels with similar chemical composition and performance of fossil jet fuels. In this context, the Hydroprocessing of Esters and Fatty Acids (HEFA) presents the most consolidated pathway for producing jet biofuels. The process for converting esters and/or fatty acids into hydrocarbons may involve hydrodeoxygenation, hydrocracking and hydroisomerization, depending on the chemical composition of the selected feedstock and the desired fuel properties. Furthermore, the HEFA process is usually performed under high H2 pressures and temperatures, with reactions mediated by a heterogeneous catalyst. In this framework, supported noble metals have been preferably employed in the HEFA process; however, some efforts were reported to utilize non-noble metals, achieving a similar performance of noble metals. Besides the metallic site, the acidic site of the catalyst is crucial for product selectivity. Bifunctional catalysts have been employed for the complete process of jet biofuel production with standardized properties, with a special remark for using zeolites as support. The proper design of heterogeneous catalysts may also reduce the consumption of hydrogen. Finally, the potential of enzymes as catalysts for intermediate products of the HEFA pathway is highlighted.

Dataset for techno-economic analysis of catalytic hydrothermolysis pathway for jet fuel production

This detail the economics of Catalytic Hydrothermolysis (CH), an approve pathway for sustainable aviation fuel (SAF) production. Techno-economic analysis was conducted with the assumption of CH processing facility that process 832 metric tonnes per day of feedstock into renewable fuels such as SAF, gasoline and diesel. Economic data includes estimation of renewable fuel production plant cost such as capital and operating cost; cost benefit analysis model to predict the SAF or jet fuel price; regression models to evaluate the cost for co-product such as diesel and petroleum in relation to SAF price. Estimated SAF, gasoline and diesel cost for the feedstock such as carinata oil, soybean oil, yellow grease and brown grease feedstock is included in the data.

Biofuel Options for Marine Applications: Technoeconomic and Life-Cycle Analyses

This study performed technoeconomic and life-cycle analyses to assess the economic feasibility and emission benefits and tradeoffs of various biofuel production pathways as an alternative to conventional marine fuels. We analyzed production pathways for (1) Fischer-Tropsch diesel from biomass and cofeeding biomass with natural gas or coal, (2) renewable diesel via hydroprocessed esters and fatty acids from yellow grease and cofeeding yellow grease with heavy oil, and (3) bio-oil via fast pyrolysis of low-ash woody feedstock. We also developed a new version of the Greenhouse gases, Regulated Emissions, and Energy use in Transportation (GREET) marine fuel module for the estimation of life-cycle greenhouse gas (GHG) and criteria air pollutant (CAP) emissions of conventional and biobased marine fuels. The alternative fuels considered have a minimum fuel selling price between 2.36 and 4.58 $/heavy fuel oil gallon equivalent (HFOGE), and all exhibit improved life-cycle GHG emissions compared to heavy fuel oil (HFO), with reductions ranging from 40 to 93%. The alternative fuels also exhibit reductions in sulfur oxides and particulate matter emissions. Additionally, when compared with marine gas oil and liquified natural gas, they perform favorably across most emission categories except for cases where carbon and sulfur emissions are increased by the cofed fossil feedstocks. The pyrolysis bio-oil offers the most promising marginal CO₂ abatement cost at less than $100/tonne CO₂e for HFO prices >$1.09/HFOGE followed by Fischer-Tropsch diesel from biomass and natural gas pathways, which fall below $100/tonne CO₂e for HFO prices >$2.25/HFOGE. Pathways that cofeed fossil feedstocks with biomass do not perform as well for marginal CO₂ abatement cost, particularly at low HFO prices. This study indicates that biofuels could be a cost-effective means of reducing GHG, sulfur oxide, and particulate matter emissions from the maritime shipping industry and that cofeeding biomass with natural gas could be a practical approach to smooth a transition to biofuels by reducing alternative fuel costs while still lowering GHG emissions, although marginal CO₂ abatement costs are less favorable for the fossil cofeed pathways.

Recent advances in one-stage conversion of lipid-based biomass-derived oils into fuel components - aromatics and isomerized alkanes

Nowadays, production of biofuels is a rather hot topic due to depleting of conventional fossil fuel feedstocks and a number of other factors. Plant lipid-based feedstocks are very important for production of diesel-, kerosene-, and gasoline-like hydrocarbons. Usually, (hydro)deoxygenation processes are aimed at obtaining of linear hydrocarbons known to have poor fuel characteristics compared to the branched ones. Thus, further hydroisomerization is required to improve their properties as motor fuel components. This review article is focused on conversion of lipid-based feedstocks and model compounds into high-quality fuel components for a single step - direct cracking into aromatics and merged hydrodeoxygenation-hydroisomerization to obtain isoparaffins. The second process is quite novel and a number of the research articles presented in the literature is relatively low. As auxiliary subsections, hydroisomerization of straight hydrocarbons and techno-economic analysis of renewable diesel-like fuel production are briefly reviewed as well.

Sustainability Assessment and Engineering of Emerging Aircraft Technologies—Challenges, Methods and Tools

Driven by concerns regarding the sustainability of aviation and the continued growth of air traffic, increasing interest is given to emerging aircraft technologies. Although new technologies, such as battery-electric propulsion systems, have the potential to minimise in-flight emissions and noise, environmental burdens are possibly shifted to other stages of the aircraft’s life cycle, and new socio-economic challenges may arise. Therefore, a life-cycle-oriented sustainability assessment is required to identify these hotspots and problem shifts and to derive recommendations for action for aircraft development at an early stage. This paper proposes a framework for the modelling and assessment of future aircraft technologies and provides an overview of the challenges and available methods and tools in this field. A structured search and screening process is used to determine which aspects of the proposed framework are already addressed in the scientific literature and in which areas research is still needed. For this purpose, a total of 66 related articles are identified and systematically analysed. Firstly, an overview of statistics of papers dealing with life-cycle-oriented analysis of conventional and emerging aircraft propulsion systems is given, classifying them according to the technologies considered, the sustainability dimensions and indicators investigated, and the assessment methods applied. Secondly, a detailed analysis of the articles is conducted to derive answers to the defined research questions. It illustrates that the assessment of environmental aspects of alternative fuels is a dominating research theme, while novel approaches that integrate socio-economic aspects and broaden the scope to battery-powered, fuel-cell-based, or hybrid-electric aircraft are emerging. It also provides insights by what extent future aviation technologies can contribute to more sustainable and energy-efficient aviation. The findings underline the need to harmonise existing methods into an integrated modelling and assessment approach that considers the specifics of upcoming technological developments in aviation.

Cost and Profitability Analysis of a Prospective Pennycress to Sustainable Aviation Fuel Supply Chain in Southern USA

This study evaluates biorefinery bio-oil feedstock costs at the plant gate for a prospective field pennycress (Thlaspi arvense L.) to sustainable aviation fuel (SAF) supply chain. The biorefinery would supply SAF to the Nashville, Tennessee international airport. Supply chain activities include pennycress production, transporting oilseed to a crushing facility, processing of oilseed into bio-oil, and transporting bio-oil to the biorefinery. The analysis shows profit potential for economic agents in the prospective supply chain. Estimated breakeven cost (profit = 0) of growing, harvesting, and transporting oilseed to a crushing facility is 17.7 ¢ kg−1. A crushing facility can pay up to 23.8 ¢ kg−1 for pennycress oilseed during the first year of production and provide investors 12.5% annual rate of return. Therefore, a profit margin of up to 6.1 ¢ kg−1 is available for the crushing facility to induce prospective pennycress producers to supply oilseed for SAF production. However, the estimated profit margin was sensitive mainly to uncertain oilseed yields, changes in field production costs, and pennycress meal and bio-oil prices. A spatial biorefineries sitting model, the Biofuels Facility Location Analysis Modeling Endeavor, estimated that the least-cost supply chain configuration is to establish three crushing facilities located in Union City, Huntington, and Clarksville, TN, to supply bio-oil to the biorefinery, with the biorefinery sited in an industrial park about 24.14 km from the Nashville international airport aviation fuel storage. Estimated total costs of bio-oil at the biorefinery plant gate are between 83 and 109 ¢ kg−1 if crushing facility oilseed procurement costs are between 17.7 and 23.8 ¢ kg−1 for oilseed.

Could Biomass Derived Fuels Bridge the Emissions Gap between High Speed Rail and Aviation?

Aviation is a steadily growing sector, which largely contributes to transport greenhouse gas (GHG) emissions. When High Speed Rail (HSR) and aviation are considered as alternative options, HSR proves to be a more environmentally friendly mode of transport. Public available data have been used in order to calculate the emission profiles on two selected intra-European routes (London–Paris and Frankfurt–Amsterdam) by HSR and air. As expected, the air mode results in higher GHG emissions and solutions for mitigating its impact have been analyzed and suggested. Biomass Derived Fuels (BDF) has a limited, up to now, potential, to fill the existing gap in terms of emissions with rail. Moreover, BDF reduction in GHG emissions is accompanied with by an increase in fuel cost. Finally, the cost per tonne of avoided CO2e by using BDF—which values 186 €/t—has been compared with the prices of the European Union (EU) Emission Trading System (ETS) allowances and, from a purely economic perspective, this market based measure still seems a preferable option to curb the GHG emissions of the air mode.

A Non-Probabilistic Solution for Uncertainty and Sensitivity Analysis on Techno-Economic Assessments of Biodiesel Production with Interval Uncertainties

Techno-economic assessments (TEA) of biodiesel production may comply with various economic and technical uncertainties during the lifespan of the project, resulting in the variation of many parameters associated with biodiesel production, including price of biodiesel, feedstock price, and rate of interest. Engineers may only collect very limited information on these uncertain parameters such as their variation intervals with lower and upper bound. This paper proposes a novel non-probabilistic strategy for uncertainty analysis (UA) in the TEA of biodiesel production with interval parameters, and non-probabilistic reliability index (NPRI) is employed to measure the economically feasible extent of biodiesel production. A sensitivity analysis (SA) indicator is proposed to assess the sensitivity of NPRI with regard to an individual uncertain interval parameter. The optimization method is utilized to solve NPRI and SA. Results show that NPRI in the focused biodiesel production of interest is 0.1211, and price of biodiesel, price of feedstock, and cost of operating can considerably affect TEA of biodiesel production.