Biofuel

The principles and recent progress in the research and development of photobiological hydrogen production are reviewed. Cyanobacteria produce hydrogen gas using nitrogenase and/or hydrogenase. Hydrogen production mediated by native hydrogenases in cyanobacteria occurs under in the dark under anaerobic conditions by degradation of intracellular glycogen. In vitro and in vivo coupling of the cyanobacterial photosynthetic system with a clostridial hydrogenase

The growing petroleum deficit requires the development of alternative fuel sources. Biodiesel is a good alternative, as it is a biodegradable and renewable product, which obeys the carbon cycle. In this work, the biodiesel from babassu was synthesized using the methanol route, and characterized by physico-chemical analyses in order to make able the investigated biodiesel to fulfill with its properties the requirements of Brazilian National Agency for Petroleum, Natural Gas and Biofuel (ANP). Besides gas chromatography, IR spectroscopy experiments and thermoanalytical measurements in air and in nitrogen were done to determine the main thermal decomposition processes and calorimetric events. The evaporation temperature of babassu biodiesel was similar in both atmospheres, started around 52 in air and around 60°C in nitrogen.

Biodiesel fuels derived from different feedstocks may have significantly different fatty acid profiles and physicochemical properties. To gain further insight into the effect of the biodiesel chemical structure, specifically its degree of unsaturation, on engine performance, combustion characteristics, and emissions, an experimental investigation was conducted on a high-speed direct-injection automotive diesel engine fueled with three mixtures of fatty acid methyl esters. The fuel matrix was designed such that the effect of the degree of unsaturation of the tested biodiesel fuels was isolated. This allowed for the maximization of the effect of the cetane number, while the other properties, such as the chain length, oxygen content, density, viscosity, and volatility, varied within a small range. Results indicated that the degree of unsaturation of biodiesel fuels did not significantly affect engine performance and the start of injection, but it had a noticeable influence on combustion characteristics and emissions, via its effect on the cetane number. A higher degree of unsaturation of biodiesel fuels led to a longer ignition delay and, consequently, a more retarded start of combustion. Regardless of the engine-operating mode, an almost fixed start of injection was attained, while the premixed portion of combustion, peak heat release rate, maximum pressure gradient, peak in-cylinder bulk-gas-averaged temperature, total hydrocarbon (THC) emissions, smoke opacity, and nitrogen oxides (NO x) emissions increased with the degree of unsaturation.

Switchgrass (Panicum virgatum L.) is a potential biofuel crop in the midwestern United States. The objective of this experiment was to test the effect of nitrogen application on biomass dry matter yield and fiber and mineral concentrations in large field plots in Lucas and Wayne counties in southern Iowa. Two established switchgrass fields with a previous history of limited management were evaluated from 1998 through 2002. Nitrogen was applied in the spring at rates of 0, 56, 112, and 224 kg N ha −1 , and a single biomass harvest was made in autumn. Biomass production averaged across locations and N levels increased by 3.6 mg ha −1 between 1998 and 2002 to 6.5 mg ha −1. Nitrogen improved yields, with the response declining as N levels increased. The highest yield throughout the experiment was 8.5 mg ha −1 at the Lucas location in 2002. Changes in fiber and mineral concentrations did not follow any trend over years but were likely due to differences in harvest date among years. Nitrogen fertilization had no meaningful effect on the quality of the biofuel produced. This study clearly shows that nitrogen application and proper agronomic management can substantially increase the yield of established switchgrass fields over time without affecting the quality of the feedstock. As this experiment was conducted in large plots using commercial farm machinery, the results should be broadly applicable to real world situations.

Vegetable oils are produced from numerous oil seed crops. While all vegetable oils have high energy content, most require some processing to assure safe use in internal combustion engines. Some of these oils already have been evaluated as substitutes for diesel fuels. The eects of vegetable oil fuels and their methyl esters (raw sun¯ower oil, raw cottonseed oil, raw soybean oil and their methyl esters, re®ned corn oil, distilled opium poppy oil and re®ned rapeseed oil) on a direct injected, four stroke, single cylinder diesel engine performance and exhaust emissions was investigated in this paper. The results show that from the performance viewpoint, both vegetable oils and their esters are promising alternatives as fuel for diesel engines. Because of their high viscosity, drying with time and thickening in cold conditions, vegetable oil fuels still have problems, such as¯ow, atomization and heavy particulate emissions. Ó

HIGHLIGHTS  The performance of different carbon-based cathodes was compared in a dual-chambered microbial fuel cell.  A novel CNT/Pt-coated carbon paper was fabricated.  The maximum current and power generated were 82.38 mA/m 2 and 16.26 mW/m 2 , respectively. Aeration in the cathode compartment was found effective on power generation in MFCs.

Bio-oil and bio-char were produced from corn cobs and corn stover (stalks, leaves and husks) by fast pyrolysis using a pilot scale fluidized bed reactor. Yields of 60% (mass/mass) bio-oil (high heating values are w20 MJ kg À1 , and densities >1.0 Mg m À3) were realized from both corn cobs and from corn stover. The high energy density of bio-oil, w20-32 times on a per unit volume basis over the raw corn residues, offers potentially significant savings in transportation costs particularly for a distributed ''farm scale'' bio-refinery system. Biochar yield was 18.9% and 17.0% (mass/mass) from corn cobs and corn stover, respectively. Deploying the bio-char co-product, which contains most of the nutrient minerals from the corn residues, as well as a significant amount of carbon, to the land can enhance soil quality, sequester carbon, and alleviate environmental problems associated with removal of crop residues from fields.

In this study, a substitute fuel for diesel engines was produced from inedible animal tallow and its usability was investigated as pure biodiesel and its blends with petroleum diesel fuel in a diesel engine. Tallow methyl ester as biodiesel fuel was prepared by base-catalyzed transesterification of the fat with methanol in the presence of NaOH as catalyst. Fuel properties of methyl ester, diesel fuel and blends of them (5%, 20% and 50% by volume) were determined. Viscosity and density of fatty acid methyl ester have been found to meet ASTM D6751 and EN 14214 specifications. Viscosity and density of tallow methyl esters are found to be very close to that of diesel. The calorific value of biodiesel is found to be slightly lower than that of diesel. An experimental study was carried out in order to investigate of its usability as alternative fuel of tallow methyl ester in a direct injection diesel engine. It was observed that the addition of biodiesel to the diesel fuel decreases the effective efficiency of engine and increases the specific fuel consumption. This is due to the lower heating value of biodiesel compared to diesel fuel. However, the effective engine power was comparable by biodiesel compared with diesel fuel. Emissions of carbon monoxide (CO), oxides of nitrogen (NO x ), sulphur dioxide (SO 2 ) and smoke opacity were reduced around 15%, 38.5%, 72.7% and 56.8%, respectively, in case of tallow methyl esters (B100) compared to diesel fuel. Besides, the lowest CO, NO x emissions and the highest exhaust temperature were obtained for B20 among all other fuels. The reductions in exhaust emissions made tallow methyl esters and its blends, especially B20 a suitable alternative fuel for diesel and thus could help in controlling air pollution. Based on this study, animal tallow methyl esters and its blends with petroleum diesel fuel can be used a substitute for diesel in direct injection diesel engines without any engine modification.

Biomethanation Cookstove Appropriate technology Renewable energy a b s t r a c t Low-cost tubular digesters originally developed in tropical regions have been adapted to the extreme weather conditions of the Andean Plateau (3000e4000 m.a.s.l.). The aim of this study was to characterise biogas production in household digesters located at high altitude, operating under psychrophilic conditions. To this end, two pilot digesters were monitored and field campaigns were carried out in two representative digesters of rural communities.

The environmental impact of agricultural waste from the processing of food and feed crops is an increasing concern worldwide. Concerted efforts are underway to develop sustainable practices for the disposal of residues from the processing of such crops as coffee, sugarcane, or corn. Coffee is crucial to the economies of many countries because its cultivation, processing, trading, and marketing provide employment for millions of people. In coffee-producing countries, improved technology for treatment of the significant amounts of coffee waste is critical to prevent ecological damage. This mini-review discusses a multi-stage biorefinery concept with the potential to convert waste produced at crop processing operations, such as coffee pulping stations, to valuable biofuels and bioproducts using biochemical and thermochemical conversion technologies. The initial bioconversion stage uses a mutant Kluyveromyces marxianus yeast strain to produce bioethanol from sugars. The resulting sugar-depleted solids (mostly protein) can be used in a second stage by the oleaginous yeast Yarrowia lipolytica to produce bio-based ammonia for fertilizer and are further degraded by Mention of trade names or commercial products in this article is solely for the purpose of providing specific information and does not imply recommendation or endorsement by the US Department of Agriculture (USDA). USDA is an equal opportunity provider and employer.

Due to its environmental, economical and safety implications, methane leak detection is a crucial task to address in the biogas production industry. In this paper, we introduce Gasbot, a robotic platform that aims to automatize methane emission monitoring in landfills and biogas production sites. The distinctive characteristic of the Gasbot platform is the use of a Tunable Laser Absorption Spectroscopy (TDLAS) sensor. This sensor provides integral concentration measurements over the path of the laser beam. Existing gas distribution mapping algorithms can only handle local measurements obtained from traditional in-situ chemical sensors. In this paper we also describe an algorithm to generate 3D methane concentration maps from integral concentration and depth measurements. The Gasbot platform has been tested in two different scenarios: an underground corridor, where a pipeline leak was simulated and in a decommissioned landfill site, where an artificial methane emission source was int...

Grape seeds were deconstructed in both hydrothermal and supercritical ethanol media with a combination of two metal chlorides (TiCl 4 :MgCl 2) to produce bio-oils. The use of metal chloride additives in supercritical ethanol achieved the highest bio-oil yield of 49.2 wt% (300 °C, 30 min). Both the hydrothermal and supercritical ethanol deconstruction with the additives (TiCl 4 :MgCl 2 = 4 mmol:4mmol) produced the bio-oils with a higher heating value (HHV) of 35 MJ/Kg. Gas chromatography-mass spectrometry (GC-MS) analysis of the bio-oils showed that the major products in bio-oils from the hydrothermal deconstruction were acids while the majority products in bio-oils form the supercritical ethanol deconstruction were esters. Nuclear magnetic resonance (NMR) data of the bio-oils suggested that both hydrothermal and supercritical ethanol deconstruction with metal chlorides significantly reduced the non-condensed OH and oxygenated lignin sub-units in bio-oils; while only supercritical ethanol deconstruction with metal chlorides reduced the aliphatic OH and O-alkylated structures in bio-oils.

Biodiesel is one of the most promising alternative diesel fuels. As diesel emission regulations have become more stringent, the diesel particulate filter (DPF) has become an essential part of the aftertreatment system. Knowledge of kinetics of exhaust particle oxidation for alternative diesel fuels is useful in estimating the change in regeneration behavior of a DPF with such fuels. This study examines the characteristics of diesel particulate emissions as well as kinetics of particle oxidation using a 1996 John Deere T04045TF250 off-highway engine and 100% soy methyl ester (SME) biodiesel (B100) as fuel. Compared to standard D2 fuel, this B100 reduced particle size, number, and volume in the accumulation mode where most of the particle mass is found. At 75% load, number decreased by 38%, DGN decreased from 80 to 62 nm, and volume decreased by 82%. Part of this decrease is likely associated with the fact that the particles were more easily oxidized. Arrhenius parameters for the biodiesel fuel showed a 2-3 times greater frequency factor and ∼6 times higher oxidation rate compared to regular diesel fuel in the range of 700-825°C

Future energy technologies must be based on renewable sources of energy and they must be sustainable. This workshop will provide insight into unintended impacts of renewable energy and how they can be avoided. In order to steer away from the pitfalls and unintended effects it is essential that necessary knowledge is present to the developers and decision makers engaged in renewable energy. This is where this workshop is valuable in its discussion of unintended health and environmental impacts of various renewable energy technologies.
The workshop give the participants an introduction the the concept of unintended consequences, in connection with renewable energy. Furthermore, several approaches to improve the understanding of these consequences and methods for predicting them, will be discussed. This will include the concepts of rebound effects and consequential life cycle assessments (LCA). The workshop will encompass presentations and discussions of results from cross-disciplinary research on implementation of the alternative fuels hydrogen, electricity and biodiesel in the transport sector, as well as the assessment of environmental impacts from the production of solar cells. This will also cover impacts of the use of nanotechnology and nanomaterials in the various energy technologies. In-dept focus will also be on the formation of nanoparticles during combustion of bio-blended diesel, and the toxic effects of these new emission components.

The aims of this study were to investigate the bioethanol production of thick juice as intermediate from sugar beet processing in batch culture by free Saccharomyces cerevisiae cells and the effect of sugar concentration on ethanol yield and CO 2 weight loss rate. Thick juice and molasses of sugar beet from a domestic sugar factory were diluted with distilled water to give a total sugar concentration of 5, 10, 15, 20 and 25% (w w À1). Initial concentration of fermentable sugars of 20% (w w À1) in culture medium can be taken as optimal, enabling maximal ethanol yield (68%) and maximal CO 2 evolution rate was realized, amounting to more than 90 g L À1 h À1. The optimal concentration of fermentable sugar from thick juice for bioethanol production by free S. cerevisiae cells was 20% (w w À1) at 30 C, pH 5 and agitation rate 200 rpm gave maximum ethanol concentration of 12% (v v À1).

The Response Surface Methodology (RSM) is used here to analyse a large set of experimental data regarding the mechanical and environmental performances of an internal combustion engine (ICE) used to power a farm tractor. The aim is twofold: (i) to demonstrate the effectiveness of RSM in quantitatively assessing the effects of biofuels on a complex system like an ICE; (ii) to supply the users with easy-to-use models to predict the effect of biofuel blends on performance and emissions of tractor engines and find an optimal blend according to given user-defined parameters. The methodology showed good prediction abilities: the calculated average errors for the first models were lower than 0.38 and 1.40% on 6 test cases, with a higher accuracy in the assessment of the ICE mechanical performance. As a result, two effective and user-friendly models for torque and NOx emissions were developed; they were subsequently used to single out some fuel blends having interesting effects in terms of ...

Modeling is regarded as a suitable tool to improve biomass pyrolysis in terms of efficiency, product yield, and controllability. However, it is crucial to develop advanced models to estimate products' yield and composition as functions of biomass type/characteristics and process conditions. Despite many developed models, most of them suffer from insufficient validation due to the complexity in determining the chemical compounds and their quantity. To this end, the present paper reviewed the modeling and verification of products derived from biomass pyrolysis. Besides, the possible solutions towards more accurate modeling of biomass pyrolysis were discussed. First of all, the paper commenced reviewing current models and validating methods of biomass pyrolysis. Afterward, the influences of biomass characteristics, particle size, and heat transfer on biomass pyrolysis, particle motion, reaction kinetics, product prediction, experimental validation, current gas sensors, and potentia...

A Detroit 6I/-92 TA coach diesel engine and a Cummins NTA-855-C diesel engine were operated on fuels produced by blending methyl soyate with No. 2 diesel fuel. Seven fuels, namely, neat diesel fuel; 90:10, 80:20, 70:30, 50:50 and 25:75% (v/v) blends of diesel fuel:methyl soyate; and neat methyl soyate were prepared and tested for the performance of the Detroit engine using standard test code SAE J1349. Specific gravity, viscosity, and heating values of all seven fuels were determined. Power developed by the engine, brake specific fuel consumption, and emissions analyses including brake specific hydrocarbon, brake specific oxides of nitrogen, brake specific carbon monoxide and smoke were measured. The performance of the engine was found to be satisfactory without a significant reduction in power output on methyl soyate blends up to 30%. Based on these results, the Cummins engine was run on four fuel blends, namely, neat diesel fuel; and 90:10, 80:20 and 70:30% (v/v) blends of diesel:methyl soyate. The performance of the Cummins engine was found to be satisfactory without any significant reduction in power. Engine exhaust emissions, except NO×, were reduced for both engines as the concentration of the methyl soyate in the fuel increased. , for statistical analyses and computer programming.

Biodiesel, as an alternative fuel, is gradually receiving more popularity for use in internal combustion engines. However questions continue to arise with regard to its compatibility with elastomeric materials. The present work aims to investigate the comparative degradation of physical properties for different elastomers [e.g. ethylene propylene diene monomer (EPDM), silicone rubber (SR), polychloroprene (CR), polytetrafluroethylene (PTFE) and nitrile rubber (NBR)] upon exposure to diesel and palm biodiesel. Static immersion tests in B0(diesel), B10 (10% biodiesel in diesel), B20, B50 and B100(biodiesel) were carried out at room temperature (25 °C) for 1000 h. Different physical properties like, changes in weight and volume, hardness and tensile strength were measured at every 250 h of immersion time. Compositional changes in biodiesel due to exposure of different elastomers were investigated by Gas chromatography mass spectroscopy (GCMS). The overall sequence of compatible elastomers in palm biodiesel is found to be PTFE > SR > NBR > EPDM > CR.

http://www.sciencedirect.com/science/article/pii/S0360544210007139

Stock engine design and decision making target optimal performance with conventional diesel fuel, leading to suboptimal results for biodiesel. The main result of this study is the determination of the appropriate engine decision making for the air/fuel ratio (AFR), exhaust gas recirculation (EGR) fraction, injection (rail) pressure, and start of main fuel injection (SOI) in a modern common rail diesel engine using variablegeometry turbo charging and operating with 5% (B5) and 20% (B20) soy-based biodiesel fuel mixtures to minimize brake-specific fuel consumption (BSFC) while adhering to strict combustion noise, NO x and PM emission constraints. In so doing, this effort determined to what extent the optimal AFR, EGR fraction, rail pressure, and SOI settings can (1) overcome the well-known "biodiesel-NO x effect" and (2) mitigate the impact of lower biodiesel energy density on BSFC for B5 and B20 biodiesel blends. Study findings indicate that lower AFR, higher EGR fraction, and earlier start of main injection can completely eliminate biodiesel NO x increases with blends of soy-based biodiesel in a modern diesel engine. While the BSNO x reductions were achieved with acceptable BSPM and noise, it was not possible to reduce the BSFC for B5 and B20 to conventional diesel levels.

In this work two genus of the Jatropha family: the Jatropha gossypiifolia (JG) and Jatropha curcas L. (JC) were studied in order to delimitate their potential as raw material for biodiesel production. The oil content in wild seeds and some physical-chemical properties of the oils and the biodiesel obtained from them were evaluated. The studied physical-chemical properties of the JC and JG biodiesel are in acceptable range for use as biodiesel in diesel engines, showing a promising economic exploitation of these raw materials in semi-arid regions. However, further agronomic studies are needed in order to improve the seed production and the crude oil properties.

The feasibility of microalgae production for biodiesel was discussed. Although algae are not yet produced at large scale for bulk applications, there are opportunities to develop this process in a sustainable way. It remains unlikely, however, that the process will be developed for biodiesel as the only end product from microalgae. In order to develop a more sustainable and economically feasible process, all biomass components (e.g. proteins, lipids, carbohydrates) should be used and therefore biorefi ning of microalgae is very important for the selective separation and use of the functional biomass components. If biorefi ning of microalgae is applied, lipids should be fractionated into lipids for biodiesel, lipids as a feedstock for the chemical industry and w -3 fatty acids, proteins and carbohydrates for food, feed and bulk chemicals, and the oxygen produced should be recovered also. If, in addition, production of algae is done on residual nutrient feedstocks and CO 2 , and production of microalgae is done on a large scale against low production costs, production of bulk chemicals and fuels from microalgae will become economically feasible.

The impacts of biodiesel and a continuously regenerated (catalyzed) diesel particle filter (DPF) on the emissions of volatile unburned hydrocarbons, carbonyls, and particle associated polycyclic aromatic hydrocarbons (PAH) and nitro-PAH, were investigated. Experiments were conducted on a 5.9 L Cummins ISB, heavy-duty diesel engine using certification ultra-low-sulfur diesel (ULSD, S e 15 ppm), soy biodiesel (B100), and a 20% blend thereof (B20). Against the ULSD baseline, B20 and B100 reduced engine-out emissions of measured unburned volatile hydrocarbons and PM associated PAH and nitro-PAH by significant percentages (40% or more for B20 and higher percentage for B100). However, emissions of benzene were unaffected by the presence of biodiesel and emissions of naphthalene actually increased for B100. This suggests that the unsaturated FAME in soy-biodiesel can react to form aromatic rings in the diesel combustion environment. Methyl acrylate and methyl 3-butanoate were observed as significant species in the exhaust for B20 and B100 and may serve as markers of the presence of biodiesel in the fuel. The DPF was highly effective at converting gaseous hydrocarbons and PM associated PAH and total nitro-PAH. However, conversion of 1-nitropyrene by the DPF was less than 50% for all fuels. Blending of biodiesel caused a slight reduction in engine-out emissions of acrolein, but otherwise had little effect on carbonyl emissions. The DPF was highly effective for conversion of carbonyls, with the exception of formaldehyde. Formaldehyde emissions were increased by the DPF for ULSD and B20.

In many rural areas, poor people still depend on wood and other biomass fuels for most of their household and income-generating activities. The difficult, time-consuming work of collecting and managing traditional fuels is widely viewed as women's responsibility, which is a factor in women's disproportionate lack of access to education and income, and inability to escape from poverty. Therefore, it is important for energy access programs to have a special focus on women. New options for energy access and sustainable livelihoods, like small-scale biofuels production, can have dramatic benefits for rural women, and their families and communities. Energy development, as both a driving force and a consequence of such tremendous changes, has had profound impact on economic, social, and environmental development. Rural energy has always been a critical issue due to years of energy shortage for both households and industries. Biomass, for long time, has been the only available fuel in many rural areas. The situation in rural areas is even more critical as local demand for energy outstrips availability and the vast majority of people depend on non-commercial energy supplies. Energy is needed for household uses, such as cooking, lighting, heating; for agricultural uses, such as tilling, irrigation and post-harvest processing; and for rural industry uses, such as milling and mechanical energy and process heat. Energy is also an input to water supply, communication, commerce, health, education and transportation in rural areas.

The lack of efficient and cost-effective technologies for harvesting bulk quantities of microalgae biomass is a major obstacle to commercialisation of algae-derived biofuels. This article demonstrates the efficacy of a foam harvester that combines dispersed air flotation with foam fractionation to allow harvesting, concentration, and physical separation of particles in suspension. Fractional factorial experiments using polystyrene latex beads were combined with trials using microalgae to determine the relative importance of key design and operational variables (air flow rate, batch run time, foam column height, surfactant concentration, and surfactant type) on the particle concentration factor. The model revealed that highest concentration factors were gained using the following variables and variable interactions: cationic cetyl trimethylammonium bromide (CTAB), lower surfactant concentrations, and CTAB combined with high column heights. Variables that increased foam residence time produced the greatest concentration factors. Analyses of the harvest economics revealed that foam flotation consumes only 0.015 kWh/m 3 providing an advantageous cost-benefit relationship, and outcompeting many commonly used bulk harvesting technologies.

A large amount of studies might be found regarding the improvement of biodiesel production; however, there is a lack of information concerning both, the simultaneous comparison of the catalyst performance for different raw materials, and the final product quality. Therefore, the objective of the present study was to evaluate: (i) the biodiesel synthesis from waste frying oil, sunflower and soybean refined oil using KOH, NaOH and CH 3 ONa as catalysts; and (ii) the final product quality according to European biodiesel standard EN 14214. The results obtained showed that the use of virgin oils resulted in higher yields (reaching 97%) as compared to waste frying oils (reaching 92%). From the quality parameters, the ones that mostly depended on the reaction conditions were the kinematic viscosity and the methyl ester content (purity). Overall, KOH was less effective than the sodium based catalysts because, using KOH, purity was lower than the minimum required according to standard EN 14214 for all samples. Considering the studied feedstock, the optimum conditions which ensured that the final product was in agreement with the European biodiesel standard were: (i) 0.6 (wt%) CH 3 ONa for both virgin oils; (ii) 0.6 (wt%) NaOH for sunflower oil and 0.8 (wt%) for soybean oil and; (iii) 0.8 (wt%) using both sodium based catalysts for waste frying oils. Under optimum conditions, a purity of 99.4 (wt%) could be obtained.

Different methods for the determination of the mechanical durability (DU) of pellets and briquettes were compared by international round robin tests including different laboratories. The DUs of five briquette and 26 pellet types were determined. For briquettes, different rotation numbers of a prototype tumbler and a calculated DU index are compared. For pellets testing, the study compares two standard methods, a tumbling device according to ASAE S 269.4, the Lignotester according to Ö NORM M 7135 and a second tumbling method with a prototype tumbler. For the tested methods, the repeatability, the reproducibility and the required minimum number of replications to achieve given accuracy levels were calculated. Additionally, this study evaluates the relation between DU and particle density.

Hydrocracking of vacuum gas oil (VGO) -vegetable oil mixtures is a prominent process for the production of biofuels. In this work both pre-hydrotreated and non-hydrotreated VGO are assessed whether they are suitable fossil components in a VGO-vegetable oil mixture as feed-stocks to a hydrocracking process. This assessment indicates the necessity of a VGO pre-hydrotreated step prior to hydrocracking the VGO-vegetable oil mixture. Moreover, the comparison of two different mixing ratios suggests that higher vegetable oil content favors hydrocracking product yields and qualities. Three commercial catalysts of different activity are utilized in order to identify a range of products that can be produced via a hydrocracking route. Finally, the effect of temperature on hydrocracking VGO-vegetable oil mixtures is studied in terms of conversion and selectivity to diesel, jet/kerosene and naphtha.

Pongamia pinnata is one of the promising tree species suitable for providing oil for biodiesel production. This paper addresses the life cycle energy balance, global warming potential and acidification potential, of a small scale biodiesel system, in rural Karnataka. In addition, the system has also been expanded to generation and use of biogas from seed cake for electricity production and evaluated for its environmental impacts. The environmental impacts have been benchmarked with the life cycle impacts of fossil diesel. The results show that non-renewable energy requirement of Pongamia biodiesel system is twenty-eight times lower than that of fossil diesel. A significant increase in global warming potential (GWP) is indicated in Pongamia biodiesel system compared to fossil diesel if wood is used as fuel. GWP would be seven times less if wood is not used as fuel. Acidification and eutrophication potential of Pongamia system was found to be nil. Further, expanding the Pongamia biodiesel system to include biogas production exploits the energy available in the system. It is also observed that one hectare of Pongamia plantation is capable of completely sequestering the CO 2 released during the life cycle with additional sequestration potential up to 1 t CO 2 ha-1. Moreover, the above aspects were significantly superior in Pongamia system when compared to Jatropha biodiesel system.

BACKGROUND: This research provides a new approach to the effective use of microalgal biomass waste generated by biofuel conversion processes. In this study, a novel adsorbent for Au(III) recovery was prepared by treating microalgal residues with concentrated sulfuric acid. RESULTS: The prepared adsorbent, crosslinked microalgae, exhibited high affinity and selectivity for Au(III) over other precious and base metal ions in a hydrochloric acid medium. From the adsorption isotherms, the maximum adsorption capacity of the crosslinked microalgae for Au(III) was estimated to be 3.25 mol kg −1 (640 g kg −1), which was about eight times higher than the adsorption capacity of the microalgal residue. Microphotographs, scanning electron microscopy, and X-ray diffraction confirmed the formation of metallic Au, suggesting that a redox reaction had taken place between the adsorbent and Au(III) ions during adsorption. Comparison of Fourier-transform infrared spectra before and after adsorption indicated that hydroxyl groups as well as ether oxygen atoms in the crosslinked microalgae participated in the Au(III) uptake mechanism. It also suggested that the reduction of Au(III) to Au(0) was facilitated by hydroxyl groups in the crosslinked microalgae. CONCLUSION: The results presented in this paper are very promising for the practical use of microalgal residues for the recovery of Au(III) because of good selectivity and favorable adsorption capacity for Au(III).

Production of ethanol, biogas, pectin and limonene from citrus wastes (CWs) by an integrated process was investigated. CWs were hydrolyzed by dilute-acid process in a pilot plant reactor equipped with an explosive drainage. Hydrolysis variables including temperature and residence time were optimized by applying a central composite rotatable experimental design (CCRD). The best sugar yield (0.41 g/g of the total dry CWs) was obtained by dilute-acid hydrolysis at 150 °C and 6 min residence time. At this condition, high solubilization of pectin present in the CWs was obtained, and 77.6% of total pectin content of CWs could be recovered by solvent recovery. Degree of esterification and ash content of produced pectin were 63.7% and 4.23%, respectively. In addition, the limonene of the CWs was effectively removed through flashing of the hydrolyzates into an expansion tank. The sugars present in the hydrolyzates were converted to ethanol using baker’s yeast, while an ethanol yield of 0.43 g/g of the fermentable sugars was obtained. Then, the stillage and the remaining solid materials of the hydrolyzed CWs were anaerobically digested to obtain biogas. In summary, one ton of CWs with 20% dry weight resulted in 39.64 l ethanol, 45 m3 methane, 8.9 l limonene, and 38.8 kg pectin.

Biodiesel production from abundant bio-sources has drawn the attention of the academic as well as the industrial communities in recent years. However, one of the most serious obstacles for using biodiesel as an alternative fuel is the complicated and costly purification processes involved in its production. The difficulties involved in the separation of glycerine and other un-reacted reactants and by-products necessitate the development of new competent low cost separation processes for this purpose. In this work, a low cost quaternary ammonium salt–glycerine-based ionic liquid is proposed as a solvent for extracting glycerine from the transesterification biodiesel product. The separation technique was tested on palm oil-based produced biodiesel with KOH as a reaction catalyst. The study investigated the effect of DES:biodiesel ratio and the DES composition on the efficiency of the extraction process. The lab scale purification experiments proved the viability of the separation technique with a best DES:biodiesel molar ratio of 1:1 and a DES molar composition of 1:1 (salt:glycerine). The purified biodiesel fulfilled the EN 14214 and ASTM D 6751 standard specifications for biodiesel fuel in terms of glycerine content. A continuous separation process is suggested for industrial scale application.

Around the world, there is a growing increase in biofuels consumption, mainly ethanol and biodiesel as well as their blends with diesel that reduce the cost impact of biofuels while retaining some of the advantages of the biofuels. This increase is due to several factors like decreasing the dependence on imported petroleum; providing a market for the excess production of vegetable oils and animal fats; using renewable and biodegradable fuels; reducing global warming due to its closed carbon cycle by CO 2 recycling; increasing lubricity; and reducing substantially the exhaust emissions of carbon monoxide, unburned hydrocarbons, and particulate emissions from diesel engines. However, there are major drawbacks in the use of biofuel blends as NOx tends to be higher, the intervals of motor parts replacement such as fuel filters are reduced and degradation by chronic exposure of varnish deposits in fuel tanks and fuel lines, paint, concrete, and paving occurs as some materials are incompatible. Here, fuel additives become indispensable tools not only to decrease these drawbacks but also to produce specified products that meet international and regional standards like EN 14214, ASTM D 6751, and DIN EN 14214, allowing the fuels trade to take place. Additives improve ignition and combustion efficiency, stabilize fuel mixtures, protect the motor from abrasion and wax deposition, and reduce pollutant emissions, among other features. Two basic trends are becoming more relevant: the progressive reduction of sulfur content and the increased use of biofuels. Several additives' compositions may be used as long as they keep the basic chemical functions that are active.

In order to study solid base catalyst for biodiesel production with environmental benignity, transesterification of edible soybean oil with refluxing methanol was carried out in the presence of calcium oxide (CaO), -hydroxide (Ca(OH) 2 ), or -carbonate (CaCO 3 ). At 1 h of reaction time, yield of FAME was 93% for CaO, 12% for Ca(OH) 2 , and 0% for CaCO 3 . Under the same reacting condition, sodium hydroxide with the homogeneous catalysis brought about the complete conversion into FAME. Also, CaO was used for the further tests transesterifying waste cooking oil (WCO) with acid value of 5.1 mg-KOH/g. The yield of FAME was above 99% at 2 h of reaction time, but a portion of catalyst changed into calcium soap by reacting with free fatty acids included in WCO at initial stage of the transesterification. Owing to the neutralizing reaction of the catalyst, concentration of calcium in FAME increased from 187 ppm to 3065 ppm. By processing WCO at reflux of methanol in the presence of cation-exchange resin, only the free fatty acids could be converted into FAME. The transesterification of the processed WCO with acid value of 0.3 mg-KOH/g resulted in the production of FAME including calcium of 565 ppm.