Aviation Biofuels Research Articles

Potential yields and emission reductions of biojet fuels produced via hydrotreatment of biocrudes produced through direct thermochemical liquefaction

BackgroundThe hydrotreatment of oleochemical/lipid feedstocks is currently the only technology that provides significant volumes (millions of litres per year) of “conventional” biojet/sustainable aviation fuels (SAF). However, if biojet fuels are to be produced in sustainably sourced volumes (billions of litres per year) at a price comparable with fossil jet fuel, biomass-derived “advanced” biojet fuels will be needed. Three direct thermochemical liquefaction technologies, fast pyrolysis, catalytic fast pyrolysis and hydrothermal liquefaction were assessed for their potential to produce “biocrudes” which were subsequently upgraded to drop-in biofuels by either dedicated hydrotreatment or co-processed hydrotreatment.ResultsA significant biojet fraction (between 20.8 and 36.6% of total upgraded fuel volume) was produced by all of the processes. When the fractions were assessed against general ASTM D7566 specifications they showed significant compliance, despite a lack of optimization in any of the process steps. When the life cycle analysis GHGenius model was used to assess the carbon intensity of the various products, significant emission reductions (up to 74%) could be achieved.ConclusionsIt was apparent that the production of biojet fuels based on direct thermochemical liquefaction of biocrudes, followed by hydrotreating, has considerable potential.

Comparison of activity and stability of supported Ni2P and Pt catalysts in the hydroprocessing of palm oil into normal paraffins

The hydroprocessing of vegetable oils into normal paraffins is a very promising method for producing green diesel and bio-jet fuels. However, detailed variations in the product distribution and catalyst deactivation have been rarely reported. In this study, the conversion of commercial palm oil over supported Pt and Ni2P catalysts is investigated. Activity tests conducted at 380°C and 400°C indicate that 10 wt.% Ni2P/SiO2 and 1 wt.% Pt/Al2O3 are more active and stable among the tested catalysts. An additional test at 360°C revealed the superior hydroprocessing activity of the former catalyst. The major contributors to the activity variation of 1 wt.% Pt/Al2O3 are Pt sintering and a carbon deposit, resulting in a decrease in the Pt sites favoring decarbonylation and decarboxylation pathways. In contrast, the catalytic performance of 10 wt.% Ni2P/SiO2 is associated with an extremely low formation of carbon deposits and the Brønsted acidity responsible for the hydrodeoxygenation pathway, despite the transformation of Ni2P particles. Consequently, Ni2P/SiO2 turns out to be the most excellent among the tested catalysts for the hydroprocessing of palm oil.

Synthesis and characterization of sulfonated activated carbon as a catalyst for bio-jet fuel production from biomass and waste plastics.

Sulfonated activated carbon-based catalysts were prepared by microwaved-assisted carbonization of phosphoric acid activated corncob followed by sulfonation using concentrated sulfuric acid. Sulfonation at different temperatures and times resulted in varied SO3H group density of the SAC catalysts. Sulfonation temperature showed a significant effect on the introduction of SO3H on the AC precursor while time had minor role. The SAC catalysts were characterized by means of N2 sorption analysis (specific surface area, pore-volume, average pore width), FTIR spectroscopy, SEM imaging, and sulfur analysis. The impact of catalysts SO3H density on the product distribution and bio-oil composition from the catalytic co-pyrolysis of Douglas fir and LDPE was evaluated. The highest bio-jet fuels (aromatics and C9-16 alkanes) obtained was 97.51% using the SAC catalyst sulfonated at 100°C for 5h. Results showed that SAC has great potential as catalyst in the co-pyrolysis of biomass and plastics for the production of jet-fuel range hydrocarbons.

Advanced Hardwood Biofuels Northwest: Commercialization Challenges for the Renewable Aviation Fuel Industry

A bioenergy summit was organized by Advanced Hardwood Biofuels Northwest (AHB) to debate the barriers to the commercialization of a hybrid poplar biofuels industry for the alternative jet fuels market from the perspective of five years of AHB research and development and two recent surveys of the North American cellulosic biofuels industry. The summit showed that: (1) Growing and converting poplar feedstock to aviation fuels is technically sound, (2) an adequate land base encompassing 6.03 and 12.86 million respective hectares of croplands and rangelands is potentially available for poplar feedstock production, (3) biofuel production is accompanied by a global warming potential that meets the threshold 60% reduction mandated for advanced renewable fuels but (4) the main obstruction to achieving a workable poplar aviation fuels market is making the price competitive with conventional jet fuels. Returns on investment into biomass farms and biorefineries are therefore insufficient to attract private-sector capital the fact notwithstanding that the demand for a reliable and sustainable supply of environmentally well-graded biofuels for civilian and military aviation is clear. Eleven key findings and recommendations are presented as a guide to a strategic plan for a renewed pathway to poplar alternative jet fuels production based upon co-products, refinery co-location with existing industries, monetization of ecosystem services, public-private financing, and researching more efficient and lower-costs conversion methods such as consolidated bioprocessing.

Experimental Investigation of the Thermophysical Properties of the Bio-Aviation Fuel Surrogates: Binary and Ternary Mixtures of n-Dodecane, Methyl Butyrate, and Methyl Decanoate

For the investigation of injection characteristics of fuels in the internal combustion engines or turbines, thermophysical properties like liquid kinematic viscosity, surface tension, density, and refractive index are crucial and necessary. In this work, the liquid kinematic viscosity and surface tension were measured by surface light scattering (SLS) for the binary and ternary mixtures of n-dodecane with methyl butyrate and methyl decanoate, respectively, in the temperature ranges from (308.15 to 413.15) K for the mixtures and (298.15 to 423.15) K for methyl butyrate. Additionally, the liquid density was determined by a U-tube densimeter from (293.15 to 423.15) K, and refractive index was measured from (278.15 and 358.15) K. Furthermore, the experimental data of surface tension and kinematic viscosity for the mixtures were correlated with two proposed equations against the temperatures and mole fractions. The density and refractive index data were correlated by polynomial functions. This work provides essential data and correlation models for the crucial thermophysical properties of the binary model fuels for the bio-aviation kerosene in connection with the investigation of the fuel injection and combustion system.

Investigation of aircraft engine performance utilizing various alternative fuels

The airlines are subjected to the energy crisis and have raised environmental issues at the same time. Future engine technology advances could decrease the effect on the environment and energy consumption. Alternative fuelspotentially assist in the reduction of engine emissions and hence lower the energy-related issues. This study presents analysis of the efficiency of aircraft engines as a function of thrust force, flow of the and specific fuel consumption (SFC) at distinct mixing ratios (40% and 100%) of African natural gas, Algae, Camelina, Jatropa, Diesel, Hydrogen, Synthetic paraffinic kerosene, UK natural gas at cruising altitude. In – house Cranfield University simulation codes, PYTHIA & TURBOMATCH have been used to investigate and model a three-shaft high bypass engine analogous to RB211 - 524. The engine model has been certified and authenticated in commercial aircraft with open works found in the Bio - Synthetic Paraffinic Kerosene test program.Blended fuel of Kerosene & hydrogen (KE+HY) fuels gives values of 331.6 KN,1.2577KG/S, and 6.9512 kg/kwh for net thrust force,the flow of fuel and specific fuel feastingat mingling ratio of 40 % respectively. However, at mixing ratio of 100% Blended fuel of Kerosene & hydrogen (KE+HY) fuels gives values of 339.01 KN, 0.800KG/S, and 4.333 kg/kwh for net thrust, fuel flow, and specific fuel consumption respectively. It is found that blended fuel of Kerosene &hydrogen (KE+HY) fuels give better engine performances as compared to other alternative fuels. However, Kerosene &diesel (KE+DI) fuels have shown a slight reduction in engine performance.

PTG-HEFA Hybrid Refinery as Example of a SynBioPTx Concept—Results of a Feasibility Analysis

Limited alternative fuels for a CO2-neutral aviation sector have already been ASTM certified; synthetic paraffinic kerosene from hydrotreated esters and fatty acids (HEFA-SPK) is one of these—a sustainable aviation fuel. With the hypothesis to improve the greenhouse gas (GHG) balance of a HEFA plant by realizing the required hydrogen supply via electrolysis—power to gas (PTG)—an exemplary SynBioPTx approach is investigated in a comprehensive feasibility study, which is, regarding this comparatively new approach, a novelty in its extent. About 10 scenarios are analysed by technical, environmental, and economic aspects. Within the alternative scenarios on feedstocks, electricity supply, necessary hydrogen supply, and different main products are analysed. For different plant designs of the hybrid refinery, mass and energy balances are elaborated, along with the results of the technical assessment. As a result of this environmental assessment, the attainment of at least 50% GHG mitigation might be possible. GHG highly depends on the renewability grade of the hydrogen provision as well as on the used feedstock. One important conclusion of this economic assessment is that total fuel production costs of 1295 to 1800 EUR t−1 are much higher than current market prices for jet fuel. The scenario in which hydrogen is produced by steam reforming of internally produced naphtha proves to be the best combination of highly reduced GHG emissions and low HEFA-SPK production costs.

Analysis of current aviation biofuel technical production potential in EU28

The significant growth aviation has been observing is increasing the sector's pressure on the environment; in the EU28, passengers travelling by air in 2016 increased of 5.9% compared to 2015. The aviation industry voluntarily committed to significant aspirational goals, and identified bio-based aviation fuels as a potential means to improve its environmental performance. Despite of that, the market penetration of aviation biofuels in EU28 is almost negligible. In this paper, an assessment of the likely aviation biofuels demand has been carried out, under a baseline scenario of increasing total fuel consumption of +3% for 2016–2020 and + 3.5% up to 2030; the CO2 intensity of this growth has been calculated accordingly. Europe is a World leader in biofuel technologies; the current potential aviation biofuels is based on the HVO/HEFA technology, and the upper limit of the installed capacity can be considered approximately 2.4 Mt y−1. Nevertheless, lower production volumes can be expected as production plants are today optimized for road fuel production, not aviation. By 2025 the situation may change, with a total production capacity of 3.5 Mt y−1, and with an average potential production for aviation biofuels ranging 0.5–2 Mt y−1. The paper shows that even if today's EU nominal capacity appears large enough to support the expected aviation biofuels demand, other bottlenecks may limit the real market uptake: availability of sustainable feedstocks, competition with demand for road transport sector, etc. For this reason, a comparison of the cost for CO2 saving of other potential solutions to mitigate aviation's climate impact has also been carried out.

Catalytic Deoxygenation of the Oil and Biodiesel of Licuri (Syagrus coronata) To Obtain n-Alkanes with Chains in the Range of Biojet Fuels.

Aviation industry has the challenge of halving CO2 emissions by 2050, as compared to 2005. An alternative are drop-in biofuels, which are sustainable and fully compatible with aircraft engines and also can be mixed with fossil jet fuel. Among the feedstock for biojet fuel production, licuri (Syagrus coronata) can be highlighted as most of its fatty acids are in the jet fuel range. Thereby, this work investigated the composition and physicochemical characterization of licuri oil and licuri biodiesel, both with satisfactory results according to international standards, with the purpose of obtaining hydrocarbons in the range of jet fuel from these feedstock, by catalytic deoxygenation. The semi-batch reaction, using a 5% Pd/C catalyst at 300 °C and 207 psi, produced n-alkanes with a conversion of up to 39.2%. The n-alkane selectivity was 80.7%, in addition to CO2 selectivity of 83.4% for biodiesel, indicating the preference for the decarboxylation pathway and also confirming licuri as a potential raw material for biojet fuel.

The potential impacts of Emissions Trading Scheme and biofuel options to carbon emissions of U.S. airlines

To reduce carbon emissions, the European Union has implemented the Emissions Trading Scheme (ETS) since 2012 for intra-European commercial flights. In response, airlines have explored various means, including sustainable jet fuels. This article investigates how similar ETS policy would affect domestic carbon emissions when implemented in the United States. The study integrates a model of airlines operations optimization and multi-feedstock biojet fuels life cycle assessment to simulate decisions of biojet fuel and commercial aviation industry responding to an emission policy. We conduct a Monte-Carlo simulation on two scenarios of domestic emission schemes to investigate the adoption of biojet fuels and its impacts on carbon emissions. Our model indicates that implementing an emission policy for U.S. airlines could incentivize adoption of biofuels - a median value of 10% of total fuels in 2050- while only marginally reduce travel demand. Because of a combined effect of emission policy and improved aircraft technology, the emissions in 2050 would only increase 1.37 times the 2005 level despite passenger demand grows by a factor of 2.75. A non-parametric sensitivity analysis suggests that the price of oil, economic growth, and carbon price are the three most significant factors in affecting the fleet-level carbon emissions.

Highly efficient production of FAMEs and β-farnesene from a two-stage biotransformation of waste cooking oils

This is the first report on an ecofriendly process for producing FAMEs and β-farnesene via a two-stage biotransformation of waste cooking oils (WCOs), in which the FAMEs are referred to as biodiesel products and β-farnesene is used as a jet biofuel. First, the yield of FAMEs from untreated WCOs by Novozym 435 was 33% under the initial transesterification conditions with crude glycerol containing 46% (w/w) methanol. However, crude glycerol with highly concentrated methanol seriously inhibited fermentation for the production of β-farnesene by an engineered E. coli strain with a relatively balanced mevalonate (MVA) pathway that was constructed with the recombinant plasmids pMevT, pMBIS and pFiI. The pretreatment of WCOs and optimization of the transesterification process were successfully performed to completely eliminate fermentation repression, and the methanol content in the crude glycerol was reduced to zero. The production of β-farnesene (5.29 g/L) using this crude glycerol as a substrate was approximately 50% higher than that (3.56 g/L) produced under the initial conditions, which was more than 100% higher than that (2.62 g/L) produced using crude glycerol via chemical transesterification methods. Furthermore, the optimal transesterification process resulted in a sharply increased yield of FAMEs (96%) compared that (33%) obtained under the initial conditions. Therefore, this biotechnology achieved a high FAMEs yield and β-farnesene production and might be suitable for industrial-scale implementation.

Evaluation of Brassica carinata meal as a protein supplement for growing beef heifers1,2.

Brassica carinata is a new oilseed crop in Florida with the potential of producing high-quality jet biofuel. A high-protein meal (~40% crude protein; CP) is obtained as a byproduct of oil extraction; however, limited research is available on the utilization of this meal as a protein supplement for beef cattle. A generalized randomized block design was used to evaluate the effects of supplementation with B. carinata meal pellets on performance and attainment of puberty in growing beef heifers consuming bermudagrass hay (Cynodon dactylon) ad libitum. Sixty-four Angus crossbred heifers (240 ± 39 kg initial body weight; BW) were stratified and blocked (2 blocks: light and heavy) by initial BW and randomly allocated into 18 pens over 2 consecutive years (10 in year 1 and 8 in year 2). Within block, pens were randomly assigned to 1 of 2 treatments: 0 (CTL) or 0.3% of BW/d (as fed) of B. carinata meal pellets (BCM). Blood samples and BW were collected weekly for 70 d, before daily supplementation. Data were analyzed using PROC MIXED of SAS with repeated measures. Model included the fixed effects of treatment, day, treatment × day interactions, block, and block × treatment interactions, with the random effect of year. Plasma was analyzed for concentrations of progesterone, triiodothyronine (T3), thyroxine (T4), ceruloplasmin (Cp), and haptoglobin (Hp). An effect of treatment was observed (P ˂ 0.01) for ADG between CTL (0.14 kg) and BCM (0.42 kg). There was no treatment or block (P > 0.05) effect for concentrations of T3, T4, or Hp; however, there was an effect of day (P < 0.01) for T3, T4, and Cp. An effect of treatment (P ˂ 0.01) was observed for Cp, with CTL having greater concentrations compared with BCM. Time to attainment of puberty did not differ (P = 0.93) between treatments. Feeding B. carinata meal as a protein supplement at 0.3% of BW/d is a viable option for increasing ADG of growing beef heifers, without affecting attainment of puberty, thyroid hormone status, or eliciting an acute phase response.

Potential for biojet production from different biomass feedstocks and consolidated technological routes: a georeferencing and spatial analysis in Brazil

AbstractThis paper assesses the biojet fuel production potential in Brazil. It evaluates feedstock availability by applying a georeferencing analysis, and determines the cost‐effectiveness and greenhouse gas (GHG) emissions of selected production routes throughout their entire life cycle. This study identifies and locates Brazilian hotspots in terms of bioenergy availability and proximity to the main sites of fuel consumption and handling in the country. Findings show that the biomass availability for each crop in the hotspots would be sufficient to feed the biojet conversion plants proposed in this study. The biojet production potential in the hotspots would represent 48% of the country's jet fuel consumption in 2014, allowing the current certificated 50% blend with conventional fuel. The major biomass hotspots are close to airport and fuel logistic basis. However, even with a US$ 200.tCO–1 2 tax, hydroprocessed esters and fatty acids (HEFA) biojet is far from being competitive with petroleum‐based jet fuel, whereas the Fischer–Tropsch synthetic paraffinic kerosene (FT‐SPK) route may produce a competitive biojet. One possible pathway to incentivize biojet fuel production in Brazil would be, first, to implement carbon taxes that would allow the development of smaller plants. Then, with technological learning and larger production scales, it would be possible to reduce or even eliminate the carbon taxes. © 2019 Society of Chemical Industry and John Wiley &amp; Sons, Ltd.

Holistic approach for sustainability enhancing of hydrotreated aviation biofuels, through life cycle assessment: A Brazilian case study

Abstract A novel approach for sustainability enhancement of jet biofuel production from palm oil and soybean oil is proposed. A comparative Well-to-Wake analysis was performed assuming a supply chain in two strategic regions of Brazil, according to each raw material. The functional unit was 1.0 MJ of energy, and impacts were quantified using Impact 2002 + and Cumulative Energy Demand methods. Two different situations, referred to as scenarios, for each vegetable oil were proposed. First conversion scenario (baseline case) included conventional jet biofuel production characteristics, regarding the use of fossil hydrogen. Second conversion scenario (enhanced case) explored renewable alternatives for hydrogen production, such as residual biomass gasification, in palm oil case, and water electrolysis, for soybean oil scenario. Results indicate significant reductions, ranging from 57% to 94%, in the global warming impact category of all scenarios as compared with conventional jet fuel. Moreover, palm oil and soybean oil improved scenarios reached the lowest carbon footprint of 4.8 and 33.9 g CO2 eq/MJ, respectively. Additionally, when considering Life Cycle Energy Efficiency an increase of about 65% and 63% for palm oil and soybean oil enhanced scenarios was observed, compared to baseline cases. In the case of Fossil Energy Ratio, an increase of 4.4% and 29.6% was determined in the same vein. Besides, in all scenarios, palm oil showed lower consumption of fossil and renewable energy than soybean oil. Some limitations of the present work can be described as: economic and logistic feasibility, due to immature technologies; geographic conditions which could affect agricultural performance; and technical aspects regarding hydrogen production technologies.

A comparative techno‐economic assessment of three bio‐oil upgrading routes for aviation biofuel production

A comparative techno‐economic assessment of three bio‐oil upgrading routes for aviation biofuel production

Synthesis of Bio Jet Fuel from Crude Palm Oil by HEFA (Hydroprocessed Esters and Fatty Acids) Using Ni-Mo Catalyst Supported by Rice Husk Ash-Based SiO&lt;sub&gt;2&lt;/sub&gt;

Bio jet fuel becomes one of the feasible solutions for jet fuel inadequate supply in Indonesia. However, study in this field by far has been limited. In this study, bio jet fuel was synthesized from Crude Palm Oil (CPO) by Hydroprocessed Esters and Fatty Acid (HEFA) facilitated by Ni-Mo/SiO2 catalyst, in which the support was derived from rice husk ash. The study focused on investigating the influence of catalyst-CPO mass ratio and temperature of the catalytic process. Experimental works consisted of silica-based catalyst preparation via impregnation method, followed by sample assessments. Catalytic reactions were conducted at 20-50 bars, with temperature of reaction 300°C and 400°C. Catalyst performance were evaluated from crystallinity, composition, and activity in the reaction. Catalyst characterization shows an amorphous structured with high dispersion of Ni-Mo in rice husk ash have been produced. The HEFA process successfully obtained bio jet fuel (C10-C15 hydrocarbons) with yield and selectivity of 45.17% and 45.46%, respectively. Overall, a systematic approach shows rice husk ash has potential to be developed as a catalyst support for bio jet fuel production from crude palm oil.

Global aviation biofuels market expected to grow $131 bn by 2025

Meibomian gland secretions (or meibum) are produced by holocrine meibomian glands and are secreted in melted form onto the ocular surface of humans and animals to form a protective tear film lipid layer (TFLL). Its protective effect strongly depends on the composition and, hence, thermotropic behavior of meibum. The goal of our study was to quantitatively evaluate the melting characteristics of human meibum and model lipid mixtures using differential scanning microcalorimetry. Standard calorimetric parameters, e.g. changes in calorimetric enthalpy, transition temperatures Tm, cooperativity of melting, etc. were assessed. We found that thermotropic behavior of meibum resembled that of relatively simple mixtures of unsaturated wax esters, but showed a lower change in calorimetric enthalpy, which can be indicative of a looser packing of lipids in meibum compared with pure standards and their simple mixtures. The cooperativity of melting of meibomian lipids was comparable to that of an equimolar mixture of four oleic-acid based wax esters. We demonstrated that the phase transitions in meibum start at about 10–15 °C and end at 35–36 °C, with Tm being about 30 °C. The highly asymmetrical shape of the thermotropic peak of meibum is important for the physiology and biophysics of TFLL.

Effect of K, Co and Mo addition in Fe-based catalysts for aviation biofuels production by Fischer-Tropsch synthesis

In the search for environmentally friendly solutions to produce clean fuels, the Fischer-Tropsch Synthesis arises as a promising alternative when using syngas obtained from biomass to produce kerosene. Fe-based catalysts are typically used in this process. The addition of chemical promoters can improve the activity of these catalysts. Thus, in this work, Fe-based materials were prepared by precipitation of iron oxides and the subsequent addition of K (3% wt.), Mo and Co (6 wt%) by impregnation. Catalytic tests were carried out for 60 h at 250 °C and 20 bar in a fixed-bed reactor using syngas with a H2:CO:N2 molar ratio of 6:3:1. The addition of K and Co stabilized catalytic activity, while the selectivity to kerosene range hydrocarbon was increased up to 30%. In addition, Co and K co-promoted catalysts reached the highest CO conversion and kerosene selectivity.

Investigation of thermodynamics performance of alternative jet fuels based on decreasing threat of paraffinic and sulfur

The aviation sector implementing state-of-the-art engine technologies has made significant progress in reducing the threat of emissions through effective air traffic strategies. Unlike the developments in motor technologies, alternative solutions related to fuels are evaluated in many ways. In order to achieve the objective of emission reduction, thermodynamic performances of low-sulfur diesel and synthetic paraffinic kerosene (SPK), which are preferred as alternative fuel, were investigated. In this study, first, energy and exergy analyses were performed by comparing the fuel consumption of a turboprop engine whilst in a flight period. Energy efficiencies were found lower 6.31% and 7.73% for ultra-low sulfur jet fuels and SPK compared to jet A-1, respectively. At the end of the study, some evaluations about performance effects and improvement processes were made.

Socioeconomic effects of aviation biofuel production in Brazil: A scenarios-based Input-Output analysis

Derived from renewable feedstocks, aviation biofuel is generally perceived as inherently sustainable. However, its production involves a wide range of sectors and interacts with different actors in society. It is therefore important to understand and evaluate not only the environmental impacts of that process, but also its socioeconomic effects. At present, empirical studies assessing socioeconomic aspects of aviation biofuel are rare in scientific literature. The aim of this study, therefore, is to assess key effects of aviation biofuel production on employment, GDP, and trade balance. A scenarios-based Input-Output (IO) analysis was used to evaluate these socioeconomic effects, taking Brazilian aviation biofuel production to 2050 as an example. To address the uncertainty of IO analysis, we have proposed a stochastic simulation approach for the technical coefficients in the IO model. Four distinct scenarios were developed. In each, three potential combinations of technologies and feedstocks for producing aviation biofuel were evaluated: sugarcane via alcohol to jet (ATJ), macauba via hydro-processed esters and fatty acids (HEFA), and eucalyptus via Fischer-Tropsch (FT). Among other things, we found that the production of aviation biofuel would create around 12,000–65,000 jobs, while contributing US$200-1100 million to Brazil's GDP under different scenarios with different supply chains. The socioeconomic effects calculated deterministically were generally higher than the stochastic outcomes, which can be explained by factors such as technological learning and economic growth. Aviation biofuel production showed large positive net socioeconomic effects on employment and GDP, although some of the fossil sectors would be negatively affected. Overall, the macauba-HEFA chain (with the highest effects on employment and GDP, and the lowest effects on imports) seemed to be the most favorable of the scenarios studied, despite the relatively high level of uncertainty associated with it.