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Biofuels as a substitute for conventional aviation and motor vehicle fuels have received considerable global interest over the past decades mainly due to their perceived economic, social, and environmental benefits. Despite these economic benefits, most developing countries, including South Africa (SA), have yet to produce commercial biofuels. This study aims to inform South African policymakers. Prospective producers of biofuels about the potential socio-economic returns from producing biofuels at a commercial level through a structured rapid review of the literature differs from the peer-reviewed studies to date in South Africa, which focussed more on assessing the economic viability and environmental impacts of biofuels production. The systematic review methodology was used. About 48% of the published empirical studies reviewed integrated the socio-economic and environmental impact assessment, followed by studies that only examined the social impacts of biofuel (about 26%), about 15% of the studies examined economic impact only, and 11.54% examined the socio-economic impact. The results revealed that although the production of biofuels is associated with a positive socio-economic benefit, the biofuel industry is not viable without government support and the selling price of biofuel is not competitive relative to gasoline and petroleum alternatives. Lastly, the results revealed a need for more objective empirical studies in South Africa that can quantify the economy-wide implications of biofuels (especially second-generation biofuels) production. Only two (n = 2) of the 28 reviewed studies were conducted in South Africa from 28 studies reviewed. Both studies conducted in South Africa were feasibility studies focusing more on bioethanol; no study quantified the economy-wide impacts. The study recommends the implementation of the biofuels support mechanism by the government. Furthermore, amendments to the existing biofuels regulatory framework are recommended in order to support the production of advanced biofuels. [ABSTRACT FROM AUTHOR]

In the light of the growing importance of biofuels in the world and Ukraine's potential for its production, the current research focuses on analysing future development of liquid biofuel market and production possibilities in Ukraine until 2030 using the AGMEMOD model. The AGMEMOD model is an econometric, dynamic, partial equilibrium, multi-commodity model which has the capacity to evaluate changes in Ukrainian agricultural policy and the impacts of political decisions on the agricultural sector in Ukraine. The current paper offers an introduction of state aid in the form of direct support and tax preferences for liquid biofuels producers to meet the needs of the domestic market in biofuels and to achieve the indicative target of 10% consumption biofuels in the total consumption of motor fuel by transport sector till 2020. For the quantitative assessment of these effects, the AGMEMOD model was used. The results of this study indicate that implementation of the direct state support, introduction of the system of returning and cancelling excise duty for biofuels producers will stimulate the achievement of the indicative target of 10% biofuels' consumption by the transport sector. [ABSTRACT FROM AUTHOR]

This article presents a theoretical analysis of the use of spiral-elliptical ducts in the atomizer of a modern fuel injector. The parameters of the injected fuel stream can be divided into quantitative and qualitative. The quantitative parameter is the injection dose amount, and the qualitative parameter is characterized by the stream of injected fuel (width, atomization, opening angle, and range). The purpose of atomizer modification is to cause additional flow turbulence, which may affect the stream parameters and improve the combustion process of the combustible mixture in a diesel engine. The spiral-elliptical ducts discussed here could be used in engines powered by vegetable fuels. The stream of such fuels has worse quality parameters than conventional fuels, due to their higher viscosity and density. The proposal to use spiral-elliptical ducts is an innovative idea for diesel engines. [ABSTRACT FROM AUTHOR]

Biofuels are derived from renewable bio-mass resources and, therefore, provide a strategic advantage to promote sustainable development and to supplement conventional energy sources in meeting the rapidly increasing requirements for transportation fuels associated with high economic growth, as well as in meeting the energy needs of India's vast rural population. India is major producer of potable and industrial alcohols. The majority of distilleries use molasses as a feed stock. Ethyl alcohol is an important feed stock for the manufacturer of various chemicals. The effluent from the distillery is described as spent wash/vinasse. It was recognized in 2001 by the CPCB that concentrating or drying the spent wash and burning it with ancillary fuel, with energy recovery in the form of steam, is the most attractive alternative as a fertilizer. Distillery Spent Wash (DSW) is a rich source of organic matter and nutrients like nitrogen, phosphorus, potassium, calcium and sulfur. In addition, it contains sufficient amount of micro-nutrients such as iron, zinc, copper, manganese, boron, and molybdenum. Vinasse incineration can claim to be the best viable solution to treat distillery vinasse economically to meet the zero liquid discharge target of the industry. This review indicates that a wide range of biological as well as physicochemical treatments, over the years for the treatment of distillery spent wash. No single technology can be employed for absolute treatment of distillery spent wash. There is a need to use a mix of treatment options with adequate protocols and guidelines so that spentwash can be gainfully utilized for biogas generation, biocompost, ferti-irrigation, one time land application, irrigation, sodic land reclamation and co-processing. [ABSTRACT FROM AUTHOR]

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This review presents and discusses the progress in combining fast pyrolysis and catalytic hydrodeoxygenation (HDO) to produce liquid fuel from solid, lignocellulosic biomass. Fast pyrolysis of biomass is a well-developed technology for bio-oil production at mass yields up to ∼75%, but a high oxygen content of 35–50 wt% strongly limits its potential as transportation fuel. Catalytic HDO can be used to upgrade fast pyrolysis bio-oil, as oxygenates react with hydrogen to produce a stable hydrocarbon fuel and water, which is removed by separation. Research on HDO has been carried out for more than 30 years with increasing intensity over the past decades. Several catalytic systems have been tested, and we conclude that single stage HDO of condensed bio-oil is unsuited for commercial scale bio-oil upgrading, as the coking and polymerization, which occurs upon re-heating of the bio-oil, rapidly deactivates the catalyst and plugs the reactor. Dual or multiple stage HDO has shown more promising results, as the most reactive oxygenates can be stabilized at low temperature prior to deep HDO for full deoxygenation. Catalytic fast hydropyrolysis, which combines fast pyrolysis with catalytic HDO in a single reactor, eliminates the need for reheating condensed bio-oil, lowers side reactions, and produces a stable oil with oxygen content, H/C ratio, and heating value comparable to fossil fuels. We address several challenges, which must be overcome for continuous catalytic fast hydropyrolysis to become commercially viable, with the most urgent issues being: (i) optimization of operating conditions (temperature, H 2 pressure, and residence time) and catalyst formulation to maximize oil yield and minimize cracking, coke formation, and catalyst deactivation, (ii) development of an improved process design and reactor configuration to allow for continuous operation including pressurized biomass feeding, fast entrainment and collection of char, which is catalytically active for side reactions, efficient condensation of the produced oil, and utilization and/or integration of by-products (non-condensable gasses and char), and (iii) long-term tests with respect to catalyst stability and possible pathways for regeneration. By reviewing past and current research from fast pyrolysis and catalytic HDO, we target a discussion of the combined processes, including direct catalytic fast hydropyrolysis. By critically evaluating their potential and challenges, we finally conclude, which future steps are necessary for these processes to become industrially feasible. [ABSTRACT FROM AUTHOR]

Purpose: Diminishing fossil resources and environmental concerns associated with their vast utilization have been in focus by energy policy makers and researchers. Among the different scenarios put forth to commercialize biofuels, various biorefinery concepts have aroused global interests because of their ability in converting biomass into a spectrum of marketable products and bioenergies. This study was aimed at developing different novel castor-based biorefinery scenarios for generating biodiesel and other co-products, i.e., ethanol and biogas. In these scenarios, glycerin, heat, and electricity were also considered as byproducts. Developed scenarios were also compared with a fossil reference system delivering the same amount of energy through the combustion of neat diesel.Materials and methods: Life cycle assessment (LCA) was used to investigate the environmental consequences of castor biodiesel production and consumption with a biorefinery approach. All the input and output flows from the cultivation stage to the combustion in diesel engines as well as changes in soil organic carbon (SOC) were taken into account. Impact 2002+ method was used to quantify the environmental consequences.Results and discussion: The LCA results demonstrated that in comparison with the fossil reference system, only one scenario (i.e., Sc-3 with co-production of significant amounts of biodiesel and biomethane) had 16% lower GHG emissions without even considering the improving effect of SOC. Moreover, resource damage category of this scenario was 50% lower than that of neat diesel combustion. The results proved that from a life cycle perspective, energy should be given priority in biorefineries because it is essential for a biorefinery to have a positive energy balance in order to be considered as a sustainable source of energy. Despite a positive effect on energy and GHG balances, these biorefineries had negative environmental impacts on the other damage categories like Human Health and Ecosystem Quality.Conclusions: Although biorefineries offer unique features as promising solutions for mitigating climate change and reducing dependence on fossil fuels, the selection of biomass processing options and management decisions can affect the final results in terms of environmental evaluations and energy balance. Moreover, if biorefineries are focused on transportation fuel production, a great deal of effort should still be made to have better environmental performance in Human Health and Ecosystem Quality damage categories. This study highly recommends that future studies focus towards biomass processing options and process optimization to guarantee the future of the most sustainable biofuels. [ABSTRACT FROM AUTHOR]

Widely blended in the transportation fuels, biofuels have been generally regarded as indispensable components in the U.S. national energy portfolio. Although the current production of cellulosic biofuels has been staggering at pilot scales, it is expected that large-scale cultivation of cellulosic biofuel crops may occur when techniques for cost-effective bioconversion of lignocellulosic biomass to ethanol are available. However, it is still unclear if enough land is in existence to accommodate potential large-scale lignocellulosic crops development without negative effects on the environment and food market. The appropriate land use for the next-generation biofuel crops should be planned and allocated in a manner that the competitive use of land dedicated to food and energy production and other side effects could be minimized. This research proposes an approach of identifying the potential available land for planting switchgrass in the U.S. Midwest using a GIS-based multi-criteria analysis that combines soil and water constraint factors. The results showed that land areas of approximately 13.6 million ha are unsuitable for profitable food crops but available for switchgrass cultivation in 7 U.S. Great Plains states. The findings can assist decision-makers in formulating land use policies and related environmental management strategies. [ABSTRACT FROM AUTHOR]

The gradual shift of transportation fuels from oil based fuels to alternative fuel resources and worldwide demand for energy has been the impetus for research to produce alcohol biofuels from renewable resources which focus on utilizing simple sugars from lignocellulosic biomass, the largest known renewable carbohydrate source as an alternative. Currently, the usage of bioethanol and biodiesel do not cover an increasing demand for biofuels. Hence, there is an extensive need for advanced biofuels with superior fuel properties. Biobutanol is regarded to be an excellent biofuel compared to bioethanol in terms of energy density and hygroscopicity, could be produced through acetone-butanol-ethanol (ABE) fermentation process. Even though the ABE fermentation is one of the oldest large-scale fermentation processes, biobutanol yield by anaerobic fermentation remains sub-optimal. For sustainable industrial scale of biobutanol production, a number of obstacles need to be addressed including choice of feedstock, low product yield, product toxicity to strain, multiple end-products and downstream processing of alcohol mixtures plus the metabolic engineering for improvement of fermentation process and products. Studies on the kinetic and physiological models for fermentation using lignocellulosic biomass provide useful information for process optimization. Simultaneous saccharification and fermentation (SSF) with in-situ product removal techniques have been developed to improve production economics due to the lower biobutanol yield in the fermentation broth. The present review is attempting to provide an overall outlook on the discoveries and strategies that are being developed for biobutanol production from lignocellulosic biomass. [ABSTRACT FROM AUTHOR]

The analysis of biological resources for biofuels production in Ukraine has been carried out, and it has been shown that usage of alternative energy sources has great potential for substantially improving energy supply of the state and solving environmental problems. The directions of development and new technologies of obtaining motor fuels from biomass are systematized. It has been established that usage of different types of biofuels and their mixtures for feeding internal combustion engines involves application of modified engines in terms of structure and algorithms and usage of traditional designs of cars without significant structural changes. Moreover, the impact of biofuels on the efficient operation of the engine requires further integrated research. [ABSTRACT FROM AUTHOR]

Replacing traditional fuels with biofuels in the transport sector has been named as one of the measures in the increasingly strict environmental policy of the European Union. The Renewable Energy Sources directive and Fuel Quality Directive stipulate the minimum required amount of biofuel to be added to the motor fuel used in the transport sector. The former directive stipulates that at least 10% of fuel used in the transport sector comes from renewable sources and the latter directive the reduction of greenhouse gas emissions in fuel production by at least 6% by the year 2020. The first obstacle in implementing biofuels is to understand the requirements of the directives. The problem of replacing traditional fuels with biofuels lies in the requirements which are based on energy content and mass, not volume. Measuring by volume is primarily in the interests of entrepreneurs who are involved directly in the production and selling of fuel. At the same time, it is important to know the various effects of these directives on the results of mixing biofuels. Fuel mixtures which do not require extensive alterations of the engines in comparison to the use of 100% biofuels are preferred. Using fuel mixtures allows meeting the requirements of using biofuels whilst incurring lower costs. In order to solve the abovementioned problems, formulas have been prepared to calculate the minimum volume and relative amount of traditional fuel and biofuel in fuel mixtures to meet the requirements of the directives. The relative amounts have been used to prepare sample graphs and to characterise the formation of biofuel ratio in fuel mixture. [ABSTRACT FROM AUTHOR]

We assessed the technical and economic viability of small-scale plants producing “drop-in replacement” transportation fuels from non-food biomass and capturing and storing byproduct CO 2 in spent shale-gas wells. Additional designs considered co-processing of natural gas — the least carbon-intensive fossil fuel — to increase liquid-fuel yields and plant efficiency, with some penalty in greenhouse gas (GHG) emissions footprint. For fuels from first-of-a-kind facilities to be cost-competitive with petroleum-derived fuels when crude oil costs $100/bbl, an effective GHG emissions price in excess of $250/tCO 2,eq would be required. If lower production costs are achieved in successive facilities via innovation and experience, fuels from future plants may become cost-competitive at crude oil prices as low as $85/bbl in the absence of any GHG emissions price, and at $50/bbl with a GHG emissions price of $135/tCO 2,eq , which the Intergovernmental Panel on Climate Change suggests is an emissions price level needed before 2050 to induce the emissions reductions needed to limit global warming to 2 °C. [ABSTRACT FROM AUTHOR]

Bio-oils are typically produced by pyrolysis processes. Bio-oils can be used directly in a generator to produce electricity or upgraded to produce transportation fuels. Nowadays the interest is that they come out in a biorefinery context. This paper compares bio-oil production within three possible procedures. Targeting the bio-oil product, in virtual biorefinery #1, microalgae is processed by solvent ultrasound-assisted extraction, and lipids follow transesterification; in virtual biorefinery #2, bio-oil comes out from fresh microalgae pyrolysis, and, finally, in virtual biorefinery #3, lipid extraction leftovers proceed for slow pyrolysis. Solvent ultrasound-assisted extraction and slow pyrolysis are tested and measured experimentally using three microalgae as feedstock: Chlorella vulgaris , Nannochloropsis oculata , and Scenedesmus obliquus . These stand-alone processes are analyzed aiming to provide the best option in a virtual biorefinery context. Although very fast/slow pyrolysis produces markedly different products, previous thermogravimetry analysis allowed choosing an adequate pyrolysis temperature. Nevertheless, the influence of temperature, catalyst and nitrogen flow is depicted. The comparison indicators for final remarks relate to final energy consumption and greenhouse gas emissions. Conditions that favor bio-oil production may not be favorable in terms of energy required per mass or energy output. If mass allocation criterion is used lipid extraction followed by slow pyrolysis of the leftovers is advantageous over slow pyrolysis of fresh dry microalgae. Still the fossil energy input largely surpasses the bio-oil energy content. [ABSTRACT FROM AUTHOR]

The authors discuss opportunities to increase the use of renewable liquid fuels or biofuels. Topics covered include the production of bioethanol mainly from corn grain and other cereals, considerations for a biofuel to be a viable alternative to gasoline, and the production of first-generation (1G) and second-generation (2G) bioethanol. Also mentioned are the costs of producing 2G biofuels and potential non-food biofuel feedstocks such as forest wood resources.

ABSTRACT Biomass has been, historically, the main source of global energy, primarily for cooking, heating, and small cottage industries. It is witnessing a strong revival and is currently used in a multitude of applications. It provides between 10 and 14% of world energy, with the potential to provide 30-40 + % and is an integral component of all energy scenarios. Biomass energy is providing multiple energy, environmental, and socio-economic benefits, both modern and traditional, ranging from electricity, heat, to transportation fuels. This review provides a critical assessment of biomass energy literature. It is not an analysis of biomass energy production and conversion methods. The main themes covered are: (i) biomass energy potential and its uses; (ii) liquid biofuels for transportation; (iii) land use changes implications; (iv) the food versus fuel debate; (v) environmental and sustainability, subsidies and energy balance issues; and (vi) international biomass energy trade. An additional key concern of this review has been to identify the main shortcomings and concerns affecting biomass energy of themes stated above, e.g. problems posed by poor scientific data, land use change, food versus biofuel debate; environmental and sustainability implications, or potential impacts of international biomass energy trade. Given the broad nature of biomass energy, and the need to embraces all major issues, this review paper is in many ways an overview. © 2016 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

India today, more than ever before, needs to deploy technologies that are able to convert the 'waste' generated in the country to transportation fuels, as also to chemicals and materials. Aimed at reduction of petroleum crude-oil imports and reduction of green house gas emissions, these technologies will need to be highly India specific due to the peculiar nature in which the wastes, e.g. agricultural waste and municipal waste, present themselves across our country. The need therefore transforms to a situation wherein we need the new generation biofuel technologies to be 'made in India' for a 'swachh bharat' and in a way that adds value to the waste and hence becomes a path to generation of new enterprises in line with the 'start-up India' concept. It is however important, that the country is careful in making a judicious choice of technologies that are truly sustainable and products that are truly 'green'. [ABSTRACT FROM AUTHOR]

Using blends of bioethanol and gasoline as automotive fuel leads to a net decrease in the production of harmful emission compared to the use of pure fossil fuel. However, fuel droplet evaporation dynamics change depending on the mixing ratio. Here we use single particle manipulation techniques to study the evaporation dynamics of ethanol/gasoline blend microdroplets. The use of an electrodynamic balance enables measurements of the evaporation of individual droplets in a controlled environment, while optical tweezers facilitate studies of the behavior of droplets inside a spray. Hence, the combination of both methods is perfectly suited to obtain a complete picture of the evaporation process. The influence of adding varied amounts of ethanol to gasoline is investigated, and we observe that droplets with a greater fraction of ethanol take longer to evaporate. Furthermore, we find that our methods are sensitive enough to observe the presence of trace amounts of water in the droplets. A theoretical model, predicting the evaporation of ethanol and gasoline droplets in dry nitrogen gas, is used to explain the experimental results. Also a theoretical estimation of the saturation of the environment, with other aerosols, in the tweezers is carried out. [ABSTRACT FROM AUTHOR]

The question of whether the world needs biofuels is approached by examining the feasibility of doing without them. Even with aggressive reductions in travel growth, shifts to mass transport modes, strong efficiency improvements, and deep market penetration by vehicles running on electricity and hydrogen, there remains a large demand for dense liquid fuels in 2050 (80% of transportation fuel) and even in 2075 (50%). This demand is due largely to aviation, ocean shipping, and long-haul trucking. Acknowledging the significant uncertainties involved in such projections and the challenges faced by all candidate technologies and fuels, we conclude that it will likely be difficult to achieve a low-carbon transport sector without widespread use of biofuels, and that aggressive efforts to develop sustainable, low-carbon biofuels alongside other options are warranted. © 2015 Society of Chemical Industry and John Wiley & Sons, Ltd [ABSTRACT FROM AUTHOR]

Currently, Sweden has the largest share of renewable fuels for transport in the EU. The ambition of the Swedish Government for 2030 is for a vehicle fleet independent of fossil fuels. This paper assesses the potential future contribution of domestically produced biofuels for transport in Sweden to 2030, based on a mapping of the prospects from the actual and potential Swedish biofuel producers. There are plans for cellulose-based ethanol, methanol, DME (dimethyl ether), methane, and the biodiesel option HVO (hydrotreated vegetable oil). Continued domestic production of biofuels at current levels and the realization of all the ongoing mapped plans for additional biofuels production result in potential domestic biofuels production of 18 TWhfuel in 2023. When assuming a continued expansion of biofuels production capacity, the potential domestic biofuels production reaches about 26 TWhfuel in 2030. If the realization of the mapped biofuels plans is delayed by 5 years and the pace of continued implementation of additional biofuel capacity is also reduced, the potential domestic biofuels production is reduced to about 8 TWhfuel and 20 TWhfuel biofuels in 2020 and 2030, respectively. These two scenarios correspond to a share of biofuels of the total future energy demand for road transport in Sweden at about 10-30% in 2020 and 26-79% in 2030, depending on which official energy demand scenario is used. The actual contribution of biofuels for road transport will depend on, e.g., policies, the global development for fossil fuels and biofuels, the competition for biomass and biofuels, and future energy demand in the road transport sector. WIREs Energy Environ 2015, 4:290-306. doi: 10.1002/wene.138 For further resources related to this article, please visit the . Conflict of interest: The authors have declared no conflicts of interest for this article. [ABSTRACT FROM AUTHOR]

The use of bio-fuel as an automotive fuel is expanding around the world. However, the impact of bio-fuel on efficiency and emissions under different operating conditions are not well understood. This study investigates the impact of low concentration bio-fuel blends on the fuel consumption and acceleration of an in-house built four wheeler light weight vehicle. Methanol based fuels were blended with octane at proportions of 5, 10, and 15% by volume. Acceleration tests were performed; fuel consumption was determined, in order to assess the performance of the vehicle under real-world driving cycles and varying loading conditions. All measurements were conducted over a customized driving cycle. The results show lower consumption of fuel consisting higher concentration of methanol. However the blending of bio-fuel slightly increases the acceleration of pure octane. Properties of the different blends including heating value and viscosity are experimentally measured to identify the causes of these findings. Furthermore, the adequacy of the structural design was evaluated using a computer model of the vehicle. [ABSTRACT FROM AUTHOR]

This article critically reviews the electroanalytical methods devoted for the determination of organic compounds in automotive fuels that can range from contaminants to additives typically introduced into liquid biofuels and liquid fossil fuels. Contaminants such as aldehydes and ketones in bioethanol, free fatty acids and glycerol in biodiesel, and sulfur and nitrogen organic compounds in gasoline and diesel fuel, and additives such as colour markers and antioxidants added to fuels were determined by electroanalytical methods. Special focus is given to electrodes, electrochemical techniques, and sample preparation strategies. Future directions of research on electroanalysis of liquid fuels are presented. [ABSTRACT FROM AUTHOR]

Instruments used to regulate the consumption of oil in the transport sector include fuel taxes, biofuel requirements, and fuel-efficiency standards. However, the effects that these have on oil consumption and price vary. If market power is present in the oil market, the directions of change in consumption and price might contrast with those in a competitive market. As a result, the market structure affects not only the effectiveness of the policy instruments used to reduce oil consumption, but also the terms of trade and carbon leakage. In particular, reduced oil consumption, as a result of increased fuel-efficiency standards, will unambiguously increase the price of oil under a monopoly. [ABSTRACT FROM AUTHOR]

The paper presents some results of droplet distribution in an atomized jet with Diesel fuel and mixture Diesel oil and bio components. [ABSTRACT FROM AUTHOR]

The high cost of transportation fuels and the environmental risks associated with acquiring and using nonrenewable energy sources have created a demand for developing renewable bioenergy crops. Switchgrass (Panicum virgatum L.), a warm-season perennial grass, is a promising feedstock due to its high biomass production under a wide range of growing conditions and its satisfactory forage quality and chemical composition. West Virginia contains vast expanses of reclaimed surface mine lands that could be used to produce switchgrass as a bioenergy feedstock. This study determined dry matter yields of three switchgrass varieties (Cave-In-Rock, Shawnee, and Carthage) during the second to fourth years of production. Two research sites were established on reclaimed surface mines in southern West Virginia: Hobet and Hampshire. The Hobet site was prepared using crushed, unweathered sandstone as the soil material, and yields were significantly lower at 803 kg ha-1 averaged across varieties and years than annual yields at Hampshire. The highest yield at Hobet, with Shawnee in the third year, was 1964 kg ha-1. The Hamphire site, which was reclaimed in the late 1990s using topsoil and treated municipal sludge, averaged 5760 kg ha-1 of switchgrass across varieties and years. The highest yield, obtained with Cavein-Rock during the third year, was 9222 kg ha-1. Switchgrass yields on agricultural lands in this region averaged 12,000 kg ha-1. Although average switchgrass yields at Hampshire were about 50% lower than agricultural lands, they were greater than a target yield of 5000 kg ha-1, a threshold for economically feasible production. Yields during the fourth year from a two-harvest per year system were not significantly different from a single, end-of-year harvest at both sites. Reclaimed lands show promise for growing bioenergy crops such as switchgrass on areas where topsoil materials are replaced and amended like that at the Hampshire site. [ABSTRACT FROM AUTHOR]

Abstract: Woody biomass can be used in different ways to contribute to sustainable development. In this paper, we analyze biomass-based production of district heat, electricity, pellets and motor fuels. We calculate production cost and biomass use of products from standalone production and from different district heat production options, including only heat production and various co/polygeneration options. We optimize the different district heat production systems considering the value of co/polygenerated products, other than district heat, as equal to those produced in minimum-cost standalone plants. Also, we investigate how the scale of district heating systems influences the minimum-cost composition of production units and district heat production costs. We find that co/polygenerated district heat is more cost and fuel efficient than that from heat-only production. Also, coproduction of electricity is more efficient than of motor fuels except for dimethyl-ether production in large district heat production systems. However, the cost difference is minor between coproduction of dimethyl-ether or electricity in such systems. Integrated biopellet production increases the production of electricity or motor fuel and reduces the production cost. District heat production cost depends on fuel price, however, its dependence is reduced if district heat production system is cost-minimized and based on co/polygenerated units. Also, the optimal composition and cost of district heat production depend on the scale of the system. The demand for biopellets may limit the potential integrated production of such a product. [Copyright &y& Elsevier]

Abstract: Binary and ternary blends of fossil diesel fuel, conventional biodiesel and hydrotreated vegetable oil (HVO), both derived from soybean oil, have been proposed as a means to increase the fraction of renewable energy in automotive fuels and to boost the blending possibilities depending on the desired fuel characteristics. Biofuels can be obtained in a specialized bio-refinery for a combined production of biodiesel and HVO or in a conventional refinery (with savings of costs as a consequence of the already existing installations). Two examples of these scenarios have been set out, and the most important physical and chemical properties of the final fuel blends measured and compared. The results proved that fuel properties depend greatly on the scenario considered, and consequently the biofuel production path must be carefully decided if the fuel potential is to be fully exploited. While a simultaneous production of HVO-diesel and a later blend with biodiesel fuels produced a neutral fuel in terms of cetane number and sooting tendency, the combined production of HVO-biodiesel to be afterwards blended with fossil diesel fuel is able to change the cetane number from 45 to 65, approximately, and reduce soot by roughly 30%. [Copyright &y& Elsevier]

Abstract: The use of hydrogen produced from renewable energy sources is often reported as an attractive strategy to address the issue of urban environmental sustainability in automotive sector, and a potential alternative to fossil fuel-fed vehicles. The project ‘Filiera Idrogeno’ (Hydrogen Chain) has investigated the potential realisation of hydrogen production chains from renewables and its use as automotive fuel in Tuscany Region (Italy). In this context, life cycle assessment was used for evaluating the environmental sustainability of such chains, applied to a fleet of hydrogen vehicles for urban commercial delivery. From the energy supply side, renewable wind and biomass energy sources were considered for hydrogen production either by electrolysis or direct separation from biomass gasification syngas, according to specific simulations. Benchmarking with hydrogen produced by using Italian electricity mix was carried out. From the transport side, vehicles equipped with either fuel cell or internal combustion engine were evaluated. A benchmarking analysis with standard electric vehicles supplied with electricity produced from the same renewable energy sources was also carried out. The results give some indications on the environmental aspects of the different alternatives and on the contribution of the chain phases to the overall impacts. [Copyright &y& Elsevier]

Abstract: A renewable biofuel economy is projected as a pathway to decrease dependence on fossil fuels as well as to reduce greenhouse gases (GHG) emissions. Ethanol produced on large-scale from lignocellulosic materials is considered the automotive fuel with the highest potential. In this paper, a life cycle assessment (LCA) study was developed to evaluate the environmental implications of the production of ethanol from a fast-growing short rotation crop (SRC): eucalyptus as well as its use in a flexi-fuel vehicle (FFV). The aim of the analysis was to assess the environmental performance of three ethanol based formulations: E10, E85 and E100, in comparison with conventional gasoline. The standard framework of LCA from International Standards Organization was followed and the system boundaries included the cultivation of the eucalyptus biomass, the processing to ethanol conversion, the blending with gasoline (when required) and the final use of fuels. The environmental results show reductions in all impact categories under assessment when shifting to ethanol based fuels, excluding photochemical oxidant formation, eutrophication as well as terrestrial and marine ecotoxicity which were considerably influenced by upstream activities related to ethanol manufacture. The LCA study remarked those stages where the researchers and technicians need to work to improve the environmental performance. Special attention must be paid on ethanol production related activities, such as on-site energy generation and distillation, as well as forest activities oriented to the biomass production. The use of forest machinery with higher efficiency levels, reduction of fertilizers dose and the control of diffuse emissions from the conversion plant would improve the environmental profile. [Copyright &y& Elsevier]

Abstract: As an internal combustion engine fuel, hydrogen had been acknowledged by international auto industry to be a possible practical and economical fuel for automobile in the future. Port fuel injection is currently considered as the easiest way for hydrogen-powered vehicle application. As the key component of hydrogen system, the performance of hydrogen injector significantly influences the characteristic of the mixture before injection into the cylinder. However, current hydrogen injector system using one injector per cylinder is not capable of meeting the flow demand. To investigate the injector''s flow characteristics and find a method of improving the injector''s flux, a calibration test stand was designed for gas injectors that can exactly calibrate the injector''s flow characteristics under injection pressure from 0.2 MPa to 0.45 MPa and injection duration from 1 ms to 10 ms. The minimum injection duration that enables the injector to work steadily was found to increase from 1.8 ms to 2.1 ms, which must be considered in idling speed. In addition, a hydrogen injector model was established using a one-dimensional simulation software. The effect of the structure parameters of the hydrogen injector on the flow characteristics was studied after verification and validation of the model with test data. By comparing the test and the calculation results, the flow area between the armature and the seal was established to have the largest effect on the injector''s flow characteristics, and larger flux can be achieved by optimizing the related parameters of the injector. Therefore, the current paper can provide guidance to the technological research on hydrogen injectors in hydrogen internal combustion engine. [Copyright &y& Elsevier]

The depletion of fossil fuel-based resources and concerns for increasing emissions of CO call for new ways of producing environmentally-friendly substitutes for motor fuels and chemicals. Thermo-chemical conversion of biomass and waste using gasification is a strong candidate to meet these challenges. For efficient and cost-effective application of this technique, novel solutions for hot gas cleaning are needed. This review highlights some important areas for improvement of upgrading technologies for pressurised fluidised bed gasification systems using biomass as a fuel. [ABSTRACT FROM AUTHOR]

The environmental properties of different types of liquid biofuels are examined: bioalcohols, biodiesel, and others. They are compared with the same properties of petroleum fuels. It is shown that the properties of biofuels differ considerably from those of petroleum fuels. [ABSTRACT FROM AUTHOR]

The current biofuels landscape is chaotic. It is controlled by the rules imposed by economic forces and driven by the necessity of finding new sources of energy, particularly motor fuels. The need is bringing forth great creativity in uncovering new candidate fuel molecules that can be made via metabolic engineering. These next generation fuels include long-chain alcohols, terpenoid hydrocarbons, and diesel-length alkanes. Renewable fuels contain carbon derived from carbon dioxide. The carbon dioxide is derived directly by a photosynthetic fuel-producing organism(s) or via intermediary biomass polymers that were previously derived from carbon dioxide. To use the latter economically, biomass depolymerization processes must improve and this is a very active area of research. There are competitive approaches with some groups using enzyme based methods and others using chemical catalysts. With the former, feedstock and end-product toxicity loom as major problems. Advances chiefly rest on the ability to manipulate biological systems. Computational and modular construction approaches are key. For example, novel metabolic networks have been constructed to make long-chain alcohols and hydrocarbons that have superior fuel properties over ethanol. A particularly exciting approach is to implement a direct utilization of solar energy to make a usable fuel. A number of approaches use the components of current biological systems, but re-engineer them for more direct, efficient production of fuels. [Copyright &y& Elsevier]

Abstract: Besides the apparent need to reduce greenhouse gas emissions, other important factors contributing to the renewed interest in biofuels are energy security concerns and the need of sustainable transportation fuel. Nearly 30% of the annual CO2 emissions in the U.S. come from the transportation sector and more than half of the fuel is imported. Biofuels appear to be a promising option to reduce carbon dioxide emissions, and the reliance on imported oil concomitantly. The interest on (ligno) cellulosic ethanol is gaining momentum as corn-based ethanol is criticized for using agricultural outputs for fuel production. Among many lignocellulosic feedstocks, woodchips is viewed as one of the most promising feedstocks for producing liquid transportation fuels. The renewable and carbon neutral nature of the feedstocks, similar chemical and physical properties to gasoline, and the low infrastructure cost due to the availability of fuel flex vehicles and transportation networks make (ligno) cellulosic bioethanol an attractive option. An in-depth LCA of woodchips shows that harvesting and woodchips processing stage and transportation to the facility stage emit large amount of environmental pollutants compared to other life cycle stages of ethanol production. Our analysis also found that fossil fuel consumption and respiratory inorganic effects are the two most critical environmental impact categories in woodchips production. We have used Eco-indicator 99 based cradle-to-gate LCA method with a functional unit of 4 m3 of dry hardwood chips production. [Copyright &y& Elsevier]

To reduce emissions caused by SI engines, gasoline-ethanol blends (bioethanol) represents not only an alternative as well as an immediate response to current and future policies related to reducing pollution [10]. There are numerous scientific studies have shown that bioethanol-gasoline blends has several disadvantages. Functional parameters such as engine power, torque and BSFC are much inferior to the use of gasoline (in particular the use of fuel blends containing a higher volume of bioethanol 20%). One way to reduce these major drawbacks is the conditioning (reforming) of biofuels by external energy intake [6] in the form of direct ultrasonic irradiation, which represents an original approach in the biofuels research domain. The purpose of the experiments is to improve the energetic possibilities of biofuels, to can be use in a great proportion as blended fuel with fossil fuels. The paper presents the experimental results and data's obtained studying the influence of ultrasonic irradiation process on BE5-BE20 bioethanol- gasoline blends. To determine the influence of external energy on functional parameters of a spark ignition (SI) engine fueled with gasoline and ethanol blends was use an experimental stand equipped, developed and adjusted in accordance with the methodology of research in the field. Parameters considered in carrying out the experimental research are effective power, effective engine torque and brake specific fuel consumption. Experiments show possibilities in improving the energetic potentials of bioethanol-gasoline blends fuels for use in SI engines. Improvements exist for all considered parameters (power, torque and BSFC) for the entire range of engine speeds. For a full understanding of the phenomena that occur during the process of ultrasonic irradiation, future research is needed to determine the chemical transformations that may occur in the frame of this process. Possibilities to appear new class of peroxide compounds during ultrasonic irradiation process (due to the existence of OH radical in the molecular structure of bioethanol) may worsen the long-term storage properties of this class of fuels. Studies are also needed to establish the existence of an optimal-frequency and intensity of radiation to establish the optimum point, linked directly with the economic aspect in the development and application possibilities of such devices on SI engines. [ABSTRACT FROM AUTHOR]

The idea that has conditioning this paper was the use of biofuel based on rapeseed oil on a medium-power diesel engine, alternative power supply being used, both as with diesel fuel and with rapeseed oil mixed with diesel in various proportions. This paper presents experimental results on a diesel engine effective power and torque performance of fueled with fuels based on rapeseed oil compared with diesel fuel. Fuels used in experimental research were mixtures of rapeseed oil, rapeseed methyl ester and diesel in different proportions: 80% diesel fuel - 20% rapeseed oil, 50% diesel fuel - 50% rapeseed oil, 25%diesel fuel - 75 % rapeseed oil, 100% rapeseed oil, 100% rapeseed methyl ester (RME) and 100% diesel fuel as (reference fuel). Because the researches were focused on the use of fuels derived from rapeseed oil on the existing Romanian engines, the work initially focused on those factors that do not involve changes or adjustments to diesel engine. International researches conducted so far have highlighted the effective power and torque performance differences of fuels based on rapeseed oil in comparison with diesel fuel. In Romania there have been intensive studies on different biofuels used in diesel engines. BIOCOMB consortium of the Technical University of Cluj- Napoca in collaboration with University of Agricultural Sciences and Veterinary Medicine, from the researches made possible that Cluj- Napoca to be the first city in the country where buses fueled with biodiesel from from rapeseed oil. The novelty of these experiments refers to the fuel blends used in the experimental tests and to the importance of results of effective power and engine torque performance. Practical implications of the work are found in the immediate applicability in the possibility of increasing the performance of agricultural tractors powered by biofuels and also open new directions in applied research on ways of streamlining the use of biofuels. The theme and direction of approach in this paper represents an innovation in the field of national research. Results and conclusions issued in the work are possible due to the support of the research project co-funded by the European Social Fund through Sectoral Operational Programme Human Resources Development 2007-2013. [ABSTRACT FROM AUTHOR]

Abstract: For several years the European Union (E.U.) has been promoting the use of biofuels due to their potential benefits such as the reduction of dependence on foreign energy imports (the raw materials can be produced within the E.U.), the more stable fossil fuel prices (they can replace fossil fuels on the market), the greenhouse gas (GHG) reduction (biofuels’ raw materials fix CO2 from the atmosphere) and the fact that they can represent an additional source of income for the primary sector (biofuels’ raw materials are vegetables that can be grown and harvested). Despite the public aids (direct and indirect), biofuels are not competitive with fossil fuels at present, but it is possible that in the future the environment conditions change and biofuels might become competitive. It is difficult to assess whether this will happen or not, but it is possible to make an assessment of a future situation. This article presents two analyses with one objective: to determine if biofuels might become competitive in the future. The first analysis examines the dependencies of two quotations which have a strong relationship with fuels: the crude oil quotation and the CO2 bond quotation. The analysis of these relationships may help to forecast the future competitiveness of biofuels. For instance, biofuels’ future competitiveness will be higher if their raw material costs are not related to crude oil quotations or if they are related in a negative way (the higher the crude oil quotations the lower the raw material biofuels’ cost). The second analysis focuses on the market penetration of biofuels in the Spanish market. There are data related to biofuels monthly consumption in Spain since 2007 and it is possible to know if biofuels are gaining market quota since then. [Copyright &y& Elsevier]

From a discursive-institutionalist perspective I seek to establish the influence exerted over environmental agenda setting and policy change by ideas and discourse, through an examination of recent developments in the UK's flagship biofuels policy, the Renewable Transport Fuels Obligation (RTFO). Discursive institutionalism's central contention is that the intricate interactions between ideas and institutions should be at the centre of studies of the policy-making process. By elucidating the mutually reinforcing character of cognitive processes (including 'framing' and 'boundary work') and institutional factors (such as `standard operating procedures' and path dependency), I show how, despite a raft of countervailing evidence, significant changes in both the form and objectives of the RTFO were precluded. Longer-term research is required to establish the precise precipitating circumstances enabling such stability to result from these feedbacks, however, as it is-theoretically at least-equally likely that far shorter periods of dramatic policy change, or `paradigm shifts', will emerge. [ABSTRACT FROM AUTHOR]

Abstract: ‘Enhanced Biomass-to-Liquid’ (EBtL) refers to BtL processes (biomass gasification and liquid fuel synthesis) with a significant increase in fuel production by means of external energy inputs. The conversion yield of biomass carbon into fuel carbon is multiplied by a factor of 3 in comparison with existing (autothermal) gasification processes. The technical options of such processes are outlined and evaluated in the paper: the production cost is estimated between 0.7 and 1.2 €/litre diesel. EBtL routes enable a strong increase in biofuel production compared with today biofuel processes (i.e. ethanol plus vegetal oil). They may also be seen as an efficient way to store electricity and hydrogen (produced from processes generating no greenhouse gas emissions) into a liquid fuel made from renewable carbon and compatible with present motor technologies and fuel storage and distribution. In combination with hybrid motors (liquid fuel and electricity), these technologies may offer a realistic alternative to petroleum and help reducing greenhouse gas emissions. [ABSTRACT FROM AUTHOR]

This paper, which is the first part of a series of papers, introduces a hybrid coal, biomass, and natural gas to liquids (CBGTL) process that can produce transportation fuels in ratios consistent with current U.S. transportation fuel demands. Using the principles of the H2Car process, an almost-100% feedstock carbon conversion is attained using hydrogen produced from a carbon or noncarbon source and the reverse water-gas-shift reaction. Seven novel process alternatives that illustrate the effect of feedstock, hydrogen source, and light gas treatment on the process are considered. A complete process description is presented for each section of the CBGTL process including syngas generation, syngas treatment, hydrocarbon generation, hydrocarbon upgrading, and hydrogen generation. Novel mathematical models for biomass and coal gasification are developed to model the nonequilibrium effluent conditions using a stoichiometry-based method. Input−output relationships are derived for all vapor-phase components, char, and tar through a nonlinear parameter estimation optimization model based on the experimental results of multiple case studies. Two distinct Fischer−Tropsch temperatures and a detailed upgrading section based on a Bechtel design are used to produce the proper effluent composition to correctly match the desired ratio of gasoline, diesel, and kerosene. Steady-state process simulation results based on Aspen Plus are presented for the seven process alternatives with a detailed economic analysis performed using the Aspen Process Economic Analyzer and unit cost functions obtained from literature. Based on the appropriate refinery margins for gasoline, diesel, and kerosene, the price at which the CBGTL process becomes competitive with current petroleum-based processes is calculated. This break-even oil price is derived for all seven process flowsheets, and the sensitivity analysis with respect to hydrogen price, electricity price, and electrolyzer capital cost, is presented. [ABSTRACT FROM AUTHOR]

This paper, which is the second of a series of papers, presents an approach for the generation of a novel heat exchange and power recovery network (HEPN) for use with any large-scale process. A three-stage decomposition framework is introduced to sequentially determine the minimum hot/cold/power utility requirement, the minimum number of heat exchanger matches, and the minimum annualized cost of heat exchange. A superset of heat engine operating conditions is used to derive the heat engine design alternatives that produce the maximum amount of electricity that can be generated when there is complete integration with the process streams. Given the minimum utility loads and the appropriate subnetworks for each process flowsheet, the minimum number of heat exchanger matches is found for each subnetwork. Weighted matches and vertical heat transfer are used to distinguish among the heat exchanger sets, to postulate the appropriate set of matches that will yield the lower minimum annualized cost. Finally, a minimum annualized cost model was presented, which uses Aspen Plus process information to estimate the cost functions for a heat exchanger match and the overall heat transfer coefficient. The proposed model is then used to analyze the seven simulated process flowsheets detailed in the first part of this series of papers [Ind. Eng. Chem. Res. 2010, DOI: 10.1016/ie100063y]. Detailed case studies are presented for the three hybrid process flowsheets to highlight the key differences in the HEPN for each process. [ABSTRACT FROM AUTHOR]