Aviation Biofuels Research Articles

An assessment of the potential of alternative fuels for “greening” commercial air transportation

This paper deals with an assessment of the potential of conventional (oil-kerosene) Jet-A1/8 and alternative synthetic & biomass-derived SPK (Synthetic Paraffinic Kerosene) and LH2 (Liquid Hydrogen) fuels for “greening” commercial air transportation through reducing its fuel consumption and related direct emissions of GHG (Green House Gases) in the medium- and long-term period of time. For such a purpose, the convenient analytical models for estimating this fuel consumption and corresponding direct emissions of GHG have been developed and applied according to “what-if” scenario approach. The results have shown that: i) Introducing the alternative SPK (F-T&HRJ) fuels fully (i.e., 100% replacement of Jet-A1/8 fuel) would bring only a marginal reduction of the cumulative direct emissions of CO2. Such reduction would not substantially contribute to achieving the globally agreed targets on reducing GHG emissions; and ii) Introducing the alternative LH2 fuel would almost immediately bring rather substantive reduction of the cumulative emissions of CO2. If such introduction started earlier, it would contribute to achieving the globally agreed targets on reducing emissions of GHG during given period.

Soot formation in non-premixed counterflow flames of conventional and alternative jet fuels

With increasing concerns over fuel cost, environmental pollutions, and energy security, the development of alternative fuels from renewable sources has gained considerable attention in the past decade. To evaluate the sooting propensities of representative conventional and alternative jet fuels, the present study has investigated soot formation in non-premixed combustion for three conventional reference jet fuels, i.e., Jet-A, JP-8, and JP-5, and three selected alternative jet fuels, i.e., Fischer-Tropsch Synthetic Paraffinic Kerosene (FT-SPK), Hydroprocessed Esters and Fatty Acids from camelina (HEFA-Camelina), and Alcohol-to-Jet (ATJ). The soot volume fraction profiles of these jet fuels in the atmospheric-pressure counterflow non-premixed flame configuration were measured using Laser-Induced Incandescence technique. In addition, the effects of global strain rate and reactant concentration on soot formation were investigated. At the same stoichiometric mixture fraction, the experimental results show that the sooting level increases with increasing fuel and O2 concentrations, while it decreases with increasing global strain rate, as expected. It is also worth noting that the three alternative jet fuels tested demonstrated greater sensitivity to variations in global strain rate and reactant concentration, as compared to the three conventional jet fuels. Based on the measured soot volume fractions, the sooting propensity of the six jet fuels are ranked as follows: JP-5>Jet-A>JP-8>ATJ>FT-SPK>HEFA-Camelina. The observed ranking is consistent with the aromatics content in each jet fuel except when comparing FT-SPK and ATJ. While ATJ has a lower aromatics content than FT-SPK, it contains much heavier hydrocarbon components, thereby leading to higher sooting propensity. Furthermore, the correlations of soot volume fraction with aromatics content and hydrogen content are examined for all six jet fuels. Although such correlations work well for the three conventional jet fuels, the present results suggest that they cannot be directly transferable to the alternative jet fuels, as these alternative fuels are composed of negligible amounts of aromatics, as well as composed of distinct chemical compositions.

Maximizing Biojet Fuel Production from Triglyceride: Importance of the Hydrocracking Catalyst and Separate Deoxygenation/Hydrocracking Steps

Various parameters in the catalytic hydroconversion of triglycerides (palm oil) were carefully investigated for maximizing the production of biojet fuel. The results showed that the deoxygenation of triglyceride via hydrotreatment should be carried out in a separate reactor prior to the hydrocracking step (i.e., two-step reaction process). Otherwise, the CO generated during deoxygenation can poison the metal components in the metal/acid bifunctional catalysts (Pt/zeolites), which can cause significant imbalance between the metal and acid functions in hydrocracking. This leads to fast catalyst deactivation via coke formation, heavy formation of aromatics, and overcracking of hydrocarbons, resulting in the reduction of final biojet fuel yield. In the two-step process, the second hydrocracking step mainly determines the final biojet fuel yield, and thus, a rational design of the hydrocracking catalysts that can suppress overcracking is essential. The diffusion characteristics of the multibranched hydrocarbon...

Chemical ignition delay of candidate drop-in replacement jet fuels under fuel-lean conditions: A shock tube study

Ignition delay times were measured behind reflected shock waves under fuel lean, high pressures conditions for conventional (JP-8) and alternative jet fuels — Fischer-Tropsch (F-T), alcohol to jet (ATJ), direct sugar to hydrocarbon (DSHC), and four bio-jet — and a biodiesel-like fuel. The primary goal of this study was to investigate the effect of fuel structure on ignition delay in order to assess differences in fuel ignition delay relative to JP-8. To support this effort, the ignition characteristics of a few hydrocarbons that are proposed as jet fuel surrogate components were also investigated: n-heptane, n-dodecane, m-xylene, n-dodecane/m-xylene blend (77%/23% by volume) and 2,2,4,6,6-pentamethylheptane (iso-dodecane). Two single-pulse shock tubes (heated and non-heated) were used to obtain the current data set. Using argon as the diluent (93% by volume), the experimental conditions covered a pre-ignition temperature range of approximately 980–1800K at a pressure of 16±0.8atm and an equivalence ratio of 0.5. Experimental results show negligible differences between the ignition delay times of JP-8, F-T, DSHC, biodiesel, and the four bio-jet fuels. They are very similar to those of n-heptane, n-dodecane, n-dodecane/m-xylene blend and iso-dodecane under similar conditions. However, the ignition delay times of the ATJ were slightly longer at higher temperatures, and similar to iso-dodecane. m-Xylene reported significantly longer ignition delay times than the other fuels tested under identical conditions. Kinetic modeling results show that light branching and carbon chain length of large n-paraffins do not alter ignition delay because the predominant reactions are oxidation of C1-C4 fuel fragments. They also show for the n-dodecane/m-xylene blend that a discernable slowing of ignition delay by fuel decomposition and oxidation of m-xylene occurs at m-xylene concentrations greater than 50% (by mol.). Further testing is required to understand this behavior at stoichiometric and fuel rich conditions. In addition, an empirical correlation was obtained between the global activation energy of the measured ignition delay times for the single paraffinic species and their derived cetane numbers. This contributes to recent efforts aimed to provide relationships between pre-vaporized, homogeneous combustion properties with existing combustion indicators.

572 Evaluation of Brassica carinata meal as a protein supplement for growing beef heifers

Brassica carinatais a new oilseed crop in Florida with the potential of producing high-quality biodiesel for use as jet biofuel. A high-protein meal (∼40% CP) is obtained as a byproduct of oil extraction, however, this meal has not been tested as a potential supplement for growing beef cattle. The objective of this experiment was to determine the effects of supplementation withBrassica carinatameal (BCM) on animal performance, attainment of puberty, and blood profile in growing beef heifers consuming bermudagrass hay (Cynodon dactylon). Sixty-four Angus crossbred heifers (240 ± 39 kg initial BW) were stratified and blocked (2 blocks: light and heavy) by initial BW and randomly allocated into 18 pens over 2 consecutive yr (10 pens in yr 1 and 8 pens in yr 2). Within block, pens were randomly assigned to one of two treatments: 0 (CTL) or 0.3% of BW/d (as fed) of BCM pellets. All heifers were provided ad libitum access to bermudagrass hay and water, and BCM pellets were supplemented daily in the pen. Body weight and blood samples were collected weekly for 70 d, before the daily supplementation. Plasma was analyzed for concentrations of progesterone, triiodothyronine (T3), and thyroxine (T4). Data were analyzed as a generalized randomized block design including the fixed effects of treatment, wk, treatment × wk, block, and block × treatment, and the random effect of year. Repeated measures, with pen within year as subject, were used to analyze T3 and T4 concentrations over time. A survival analysis was conducted to determine time to attainment of puberty. There was a difference (P< 0.01) in 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 and T4; however, there was a difference in wk (P<0.01). Time to attainment of puberty did not differ between treatments (P= 0.68); however, there was an effect of block (P<0.01) where the light block heifers attained puberty earlier compared to the heavy block heifers. FeedingB. carinatameal as a protein supplement at 0.3% of BW/d is a viable option for increasing ADG of growing beef heifers, without affecting the attainment of puberty.

539 Evaluation ofBrassica carinatameal on ruminal metabolism and nutrient digestibility of beef cattle

Brassica carinatais a new oilseed crop in Florida with the potential of producing high-quality biodiesel for use as jet biofuel. A high-protein meal (∼40% CP) is obtained as a byproduct of oil extraction; however, this meal has not been tested as a potential protein supplement for cattle. A duplicated 4 × 4 Latin square design was used to determine the effects of supplementation withB. carinatameal on ruminal fermentation, digestibility, and blood profile in beef cattle consuming bahiagrass hay (Paspalum notatum), compared with frequently used protein supplements. Eight Angus crossbred steers (473 ± 119 kg initial BW) were randomly allocated to 8 pens, over 4 periods of 28 d each. Within period, steers were assigned to one of four treatments: 1.62 kg/d cottonseed meal (CSM), 2.15 kg/d dry distillers grains with solubles (DDGS), 1.39 kg/dB. carinatameal pellets (BCM), or 1.17 kg/d soybean meal (SBM), supplemented daily, on an isonitrogenous basis. Steers had ad libitum access to bahiagrass hay and water. Intake was measured using the GrowSafe system. Following a 14 d adaptation, feed and fecal samples were collected twice daily for 4 d to determine apparent total tract nutrient digestibility using iNDF as an internal marker. Blood and ruminal fluid samples were collected every 3 h, during a 24 h period, to analyze blood urea nitrogen (BUN) and glucose in plasma, as well as pH, NH3-N, and VFA concentrations in ruminal fluid. Data were analyzed using PROC MIXED of SAS with repeated measures. Model included the fixed effects of treatment, time, treatment × time, square, and period, and the random effects of steer (square) and steer (treatment). No effect of treatment (P>0.05) was observed for pH, NH3-N, or glucose concentration. An effect of treatment (P<0.01) was observed for BUN, with steers receiving SBM having greater concentrations. There was no effect of treatment (P>0.05) on total VFA concentrations. Steers consuming CSM had greatest acetate molar proportion, and greater acetate to propionate ratio when compared with DDGS and BCM. Steers consuming DDGS had greatest molar proportions of butyrate and greater molar proportions of propionate compared with SBM and CSM. There was no effect of treatment (P>0.05) on DMI or apparent total tract digestibility of DM, OM, CP, NDF, or ADF.Brassica carinataperformed similarly to commonly used protein supplements, excluding VFA profile, indicating its viability as a protein supplement for beef cattle.

Eco-innovation: Sensemaking and Strategic Responses to Institutional Uncertainty

Drawing on neoinstitutional theory and extending effectuation theory, we show how the cognitive schemas of environmental entrepreneurs and other actors in the nascent aviation biofuels industry may...

Cost calculations for three different approaches of biofuel production using biomass, electricity and CO2

To achieve the emission mitigation and decarbonization goals, future aviation requires alternative sustainable fuels. Synthetic paraffinic kerosene, generated by Fischer-Tropsch synthesis, is certified as a drop-in jet fuel up to 50%. Potential fuel production routes are via conversion of biomass (Biomass-to-Liquid, BtL), the combination of renewable power and biomass (Power-and-Biomass-to-Liquid, PBtL) and the conversion of carbon dioxide with hydrogen from renewable power (Power-to-Liquid, PtL). In order to compare the three different production routes, an Aspen Plus® model is designed for each production path and techno-economically assessed for an assumed capacity of 11 Mg h−1 fuel production (equals 90 Gg·a−1 plant capacity). Even though the BtL route allows the lowest net production costs, it has some drawbacks compared to PBtL and PtL. Especially the low H to C ratio of biomass leads to limited fuel yields in the BtL process. These yields can be increased by a factor of about 3 when conducting the PBtL process with the same biomass input instead of BtL. The highest X-to-Liquid efficiency based on power input and energy in feedstock is found for PBtL (51.4%) followed by PtL (50.6%) and BtL (36.3%). For BtL 73% of the introduced carbon is lost as CO2. The total investment costs are highest for BtL, followed by PBtL and PtL. The net production costs are in the reverse order. The cost analysis reveals total PBtL investment costs of 742 M€ and net production costs of around 3 €·kg−1 with an electricity price of 105 €·MWh−1. The costs for electrolyzer and gasifier represent the largest shares of the total capital costs. As the net production costs are dominated for the electricity costs, low electricity prices and high capacities are advantageous for PBtL, while high electricity and low biomass costs favor BtL concept.

Analysis of emission characteristics of gas turbine engines with some alternative fuels

ABSTRACTThe paper concerns the comparative analysis of combustion characteristics of different alternative fuels such as Fischer-Tropsch Synthetic Paraffinic Kerosene (FT-SPK), cryogenic methane, bioethanol, biomethanol, biobutanol, dimethyl ether, biodiesel and conventional aviation kerosene Jet-A as well as analysis of emissions of NOx, CO, CO2, H2O, HNOy (y = 2,3) and organics for gas turbine engine operating on these fuels. The analysis has shown that the usage of all considered alternative fuels results in the increase of H2O emission, compared to kerosene-fueled combustor, and, as consequence, in the growth of water vapor supersaturation that can increase the rate of the H2O vapor condensation and enhance the formation of contrails and cirrus clouds in the atmosphere. The usage of all considered alternative fuels except FT-SPK, cryogenic methane and dimethyl can increase the CO2 emission compared to using of kerosene. Emission of N-containing species can be reduced upon the usage of considered alternative fuels, except dimethyl ether, for which one can expect the increase in the emissions of HNO2 and HNO3 approximately by 10%. The emission of CO decreases for all fuels except biodiesel. The major decrease can be achieved upon the replacement of kerosene to bioethanol.

Canola as a Winter Crop in California

Canola as a Winter Crop in California

The attitudes of UK tourists to the use of biofuels in civil aviation: An exploratory study

Tourism generates substantial carbon footprint with its air transport sector holding the largest share. Biofuel technology has been repeatedly trialled in aviation to minimise this carbon footprint. While biofuels can become mainstream aviation fuels in the near future, little is known about public knowledge on and perception of its use within the air transport sector. This signifies considerable knowledge gap as the level of public awareness of a new technology determines the speed of its societal acceptance and may affect its market success. This study explores the attitudes of UK tourists to the use of biofuels in aviation. It finds that while the public are generally aware of biofuel technology, public knowledge of its specific application in aviation alongside the carbon benefits this brings is limited. Future policy-making and managerial measures should aim at enhancing public understanding of biofuel technology use in aviation in the UK.

Role of Solvent in Catalytic Conversion of Oleic Acid to Aviation Biofuels

The role of solvents in the conversion of oleic acid over Pt/C was studied. Three solvent systems (solvent-free, water, and dodecane systems) were employed for the conversion of oleic acid over Pt/C at 350 °C. Decarboxylation, hydrogen transfer, and aromatization were observed in these three reaction systems. In comparison to the non-solvent reaction system, much slower decarboxylation and aromatization rates and fewer heptadecane and aromatic products were observed in the hydrothermal and dodecane reaction systems. The decarboxylation and aromatization rates and yields of heptadecane and aromatics decreased with increased dodecane loading in the dodecane reaction system, and the decarboxylation and aromatization rates and yields of heptadecane and aromatics significantly decreased with the increase of water in the hydrothermal reaction system. The effects of solvent loading, catalyst loading, and reaction time on the reactions (decarboxylation, hydrogen transfer, and aromatization) were investigated. The...

Nodulation and Symbiotic Nitrogen Fixation in the Biofuel Legume Tree Pongamia pinnata

The legume tree Pongamia pinnata (also called Millettia pinnata) is a non-food crop that can grow on marginal land not destined for the cultivation of food crops. It is an important candidate for the production of biofuel (bio-oil, biodiesel and aviation biofuel) from its oil-rich seeds. An important trait is its ability to grow in marginal, nitrogen-limited soils. This growth ability is attributed to the nitrogen-fixation activity of root nodules. Cutting both cotyledons in halves had little effect on shoot dry weight, nodule number and weight per plant at 8 weeks. These parameters were reduced when both cotyledons were removed; plants were visibly yellow. Surprisingly when no nutrients were supplied and with both cotyledons intact, plants grew as well as those with nutrients. To isolate rhizobial inoculants from soil, samples were collected from Meandu Mine, a coal-mining site near Kingaroy, Queensland (Australia), where pongamia is currently grown to rehabilitate the soil. Pongamia nodules were also collected from Mt. Coot-tha Botanic Gardens (Brisbane), where pongamia was introduced decades ago. Established ‘Baiting technique’ and ‘One-drop-one-nodule technique’ were applied to isolate potential rhizobia from the soil samples and nodules. All isolates were screened and characterised for symbiotic effectiveness and nitrogenase activity. A total of 21 putative rhizobial samples were isolated – five from soil samples and 16 from pongamia nodules. Out of these iso lates, seven were slow-growers while 14 were fast-growers. These isolates were coded as PR-UQ. Among the isolates, the fast-growers PR-UQ-03 and PR-UQ-05 were considered as the superior strains compared to the slow-growers PR-UQ-01 and PR-UQ-04, which were more effective than the rest of the isolates. The new isolates enhanced nodule number, shoot length and total plant dry weight and resulted in better plant growth than the available Bradyrhizobium japonicum strains CB1809, USDA110 and CB564. Acetylene reduction assay (short term) and Nitrogen Difference Analysis (long term) further confirmed that pongamia fixed more nitrogen upon inoculation with these rhizobia. Based on 16S rDNA sequence analysis, PR-UQ-01 and PR-UQ-04 are closely related to Bradyrhizobium elkanii and Bradyrhizobium pachyrizi, while PR-UQ-03 and PR-UQ-05 are both related to Rhizobium mesoamericanum. Cotyledons supply the seedling with nutrients for a considerable period of early seedling growth. The newly isolated, fast-growing rhizobia PR-UQ-03 and PR-UQ-05 and the slow-growing PR-UQ-01 and PR-UQ-04 are related to Rhizobium and Bradyrhizobium species and aid in the nodulation, nitrogen fixation and seedling/sapling growth of Pongamia pinnata.

Pyrolysis mechanism of microalgae Nannochloropsis sp. based on model compounds and their interaction

Pyrolysis is one of important pathways to convert microalgae to liquid biofuels and key components of microalgae have different chemical composition and structure, which provides a barrier for large-scale microalgae-based liquid biofuel application. Microalgae component pyrolysis mechanism should be researched to optimal pyrolysis process parameters. In this study, single pyrolysis and co-pyrolysis of microalgal components (model compounds castor oil, soybean protein and glucose) were conducted to reveal interaction between them by thermogrametric analysis and bio-crude evaluation. Castor oil (model compound of lipid) has higher pyrolysis temperature than other model compounds and has the maximum contribution to bio-crude formation. Bio-crude from soybean protein has higher N-heterocyclic compounds as well as phenols, which could be important aromatic hydrocarbon source during biorefineries and alternative aviation biofuel production. Potential interaction pathways based on model compounds are recommended including further decomposition of Maillard reaction products (MRPs) and surfactant synthesis, which indicate that glucose played an important role on pyrolysis of microalgal protein and lipid components. The results should provide necessary information for microalgae pyrolysis process optimization and large-scale pyrolysis reactor design.

Biojet fuels and emissions mitigation in aviation: An integrated assessment modeling analysis

Although the aviation sector is a relatively small contributor to total greenhouse gas emissions, it is a fast-growing, fossil fuel-intensive transportation mode. Because aviation is a mode for which liquid fuels currently have no practical substitute, biofuels are gaining attention as a promising cleaner alternative. In this paper, we use the GCAM integrated assessment model to develop scenarios that explore the potential impact of biojet fuels for use in aviation in the context of broader climate change mitigation. We show that a carbon price would have a significant impact on the aviation sector. In the absence of alternatives to jet fuel from petroleum, mitigation potential is limited and would be at the expense of aviation service demand growth. However, mitigation efforts through the increased use of biojet fuels show potential to reduce the carbon intensity of aviation, without a significant impact on bioenergy use in the rest of the energy system for carbon mitigation. The potential of biofuel to decarbonize air transport is significantly enhanced when carbon dioxide capture and storage (CCS) is used in the conversion process to produce jet fuels from biomass feedstock.

Optimal planning for the supply chain of biofuels for aviation in Mexico

There are great challenges to replace fossil fuels by biofuels, including the development of efficient technologies and adequate strategic planning. For the manufacture of biofuels at the industrial scale, there is a need to optimize the overall associated supply chain. Among biofuels, the global market for the aviation biofuel has increased drastically, mainly due to the forecasted growth of the aviation sector. Nevertheless, the supply chain for the aviation biofuel has specific characteristics, which are different from the case of bioethanol and biodiesel. Therefore, this paper presents a general optimization approach for optimizing the supply chain of aviation biofuels. A case study is presented accounting for the projection of the Mexican government for implementing the use of aviation biofuel in the airport network. The application of the proposed approach generates very interesting solutions, which are grouped in a Pareto front; from these results, it can be highlighted that the demand for aviation biofuel in the Mexican market can be satisfied with a gross economic benefit of M US$ 1681 per year, and savings of 93% of carbon dioxide emissions. The generated information can contribute to the establishment of the sustainable supply chain for aviation biofuels in Mexico.

Synthesis of Biokerosene through Electrochemical Hydrogenation of Terpene Hydrocarbons from Turpentine Oil

Indonesia possesses great potential for developing renewable resources as alternative fuels. For example, turpentine oil obtained from Pinus merkusii , which contains mostly monoterpene hydrocarbons (C 10 H 16 ). The oil is highly suitable to be processed for biokerosene or even jet biofuel. It consists of hydrocarbons within the range of C 10 to C 15 . However, it contains insufficient H and thus needs to be upgraded. In the present work, electrochemical hydrogenation was used for upgrading. In the electrochemical cell, stainless steel, silver, and carbon were used alternately for the anode, while copper and silver Raschig rings were used for the cathode. An electrolyte solution of cuprous ammonium formate was utilized not only as a source of H but also to draw the unsaturated hydrocarbons into the aqueous phase. The electrolyte : oil ratio (up to 2:1), electrolyte concentration (between 0.4 and 2 M) and reaction time were varied throughout the experiments. The bromine number (unsaturation level) of the turpentine oil, which was initially 1,86 (mole Br 2 /mole), was lowered significantly to 0.69-0.90. Promising increase of smoke point values were observed from 11 mm to 16-24 mm, indicating a higher H content of the processed oil, thus making it suitable as a substitute for petroleum kerosene.

Nodulation and Symbiotic Nitrogen Fixation in the Biofuel Legume Tree Pongamia pinnata

The legume tree Pongamia pinnata (also called Millettia pinnata) is a non-food crop that can grow on marginal land not destined for the cultivation of food crops. It is an important candidate for the production of biofuel (bio-oil, biodiesel and aviation biofuel) from its oil-rich seeds. An important trait is its ability to grow in marginal, nitrogen-limited soils. This growth ability is attributed to the nitrogen-fixation activity of root nodules. Cutting both cotyledons in halves had little effect on shoot dry weight, nodule number and weight per plant at 8 weeks. These parameters were reduced when both cotyledons were removed; plants were visibly yellow. Surprisingly when no nutrients were supplied and with both cotyledons intact, plants grew as well as those with nutrients. To isolate rhizobial inoculants from soil, samples were collected from Meandu Mine, a coal-mining site near Kingaroy, Queensland (Australia), where pongamia is currently grown to rehabilitate the soil. Pongamia nodules were also collected from Mt. Coot-tha Botanic Gardens (Brisbane), where pongamia was introduced decades ago. Established ‘Baiting technique’ and ‘One-drop-one-nodule technique’ were applied to isolate potential rhizobia from the soil samples and nodules. All isolates were screened and characterised for symbiotic effectiveness and nitrogenase activity. A total of 21 putative rhizobial samples were isolated – five from soil samples and 16 from pongamia nodules. Out of these iso lates, seven were slow-growers while 14 were fast-growers. These isolates were coded as PR-UQ. Among the isolates, the fast-growers PR-UQ-03 and PR-UQ-05 were considered as the superior strains compared to the slow-growers PR-UQ-01 and PR-UQ-04, which were more effective than the rest of the isolates. The new isolates enhanced nodule number, shoot length and total plant dry weight and resulted in better plant growth than the available Bradyrhizobium japonicum strains CB1809, USDA110 and CB564. Acetylene reduction assay (short term) and Nitrogen Difference Analysis (long term) further confirmed that pongamia fixed more nitrogen upon inoculation with these rhizobia. Based on 16S rDNA sequence analysis, PR-UQ-01 and PR-UQ-04 are closely related to Bradyrhizobium elkanii and Bradyrhizobium pachyrizi, while PR-UQ-03 and PR-UQ-05 are both related to Rhizobium mesoamericanum. Cotyledons supply the seedling with nutrients for a considerable period of early seedling growth. The newly isolated, fast-growing rhizobia PR-UQ-03 and PR-UQ-05 and the slow-growing PR-UQ-01 and PR-UQ-04 are related to Rhizobium and Bradyrhizobium species and aid in the nodulation, nitrogen fixation and seedling/sapling growth of Pongamia pinnata.

Erratum to: Life cycle assessment of integrated seawater agriculture in the Arabian (Persian) Gulf as a potential food and aviation biofuel resource

Prospective evaluation of the lifecycle impacts of aviation biofuel production in Abu Dhabi, UAE based on a production system that integrates aquaculture, saltwater agriculture, and mangrove silviculture, termed an Integrated Seawater Energy Agriculture System (ISEAS) in order to investigate its energetic and environmental potential compared to conventional fuels. We compare the hydroprocessed renewable jet fuel (HRJ) produced from ISEAS against fossil jet fuel using a life cycle assessment (LCA) methodology. Based on a detailed description of the production process, we use data from a wide-ranging literature review and experimental results from the specific location to make informed assumptions for the range of the process inputs and yields. We then analyze several process configuration scenarios with different ranges. ISEAS can produce aviation biofuels, electricity, and food while afforesting coastal desert land, acting as a long-term sink for carbon, minimizing freshwater consumption, and having beneficial land use impacts when compared to fossil jet fuel production. Based on a sensitivity analysis, we show that ISEAS HRJ emits 38 to 68% less greenhouse gases than fossil jet fuel and yields an overall positive net energy balance under all scenarios except one with an extensive use of desalinated water. ISEAS offers a promising pathway for integrating aquaculture and seawater agriculture in arid regions. It is essentially a process to sustainably augment aquaculture-based products by using its waste as a biofuel resource. Achieving positive emissions results depend critically on minimizing freshwater use, maximizing biomass yield and to a lesser extent the performance of biomass gasification.

Life cycle assessment of integrated seawater agriculture in the Arabian (Persian) Gulf as a potential food and aviation biofuel resource

Life cycle assessment of integrated seawater agriculture in the Arabian (Persian) Gulf as a potential food and aviation biofuel resource