Future Fuels Research Articles

The Sustainability, a Relevant Approach for Defining the Roadmap for Future Nuclear Fuel Cycles

In the framework of the COP21 agreement of December 2015, nuclear energy could help mitigating the global climate change together with the renewable energies, due to its low green-house-gases emissions, its reliability and its high base-load capacity. However, the political uncertainty in many countries about the future of nuclear energy source clearly illustrates that there is a need for a global approach to compare nuclear energy with other energy sources and draw its potential future improvements. Indeed, beyond the well-known economic aspect, many other criteria are also implicitly considered when choosing a relevant energy mix to be implemented in a given country. This rather recent situation requires extending the classical approach based on the technological and economic optimization to a wider approach also including the overall environmental footprint and the more general social acceptance. Sustainability approach includes the different criteria describing the environmental, economic and societal fields. Therefore, it may be relevant to identify the current key figures of nuclear energy, and help to identify the most promising improvement directions. In this paper, we propose to assess the current nuclear fuel cycles regarding the different sustainability criteria. We will also address the most relevant improvements to be implemented in the future to ensure the sustainability of nuclear energy and support its development.

Combustion Analysis and Devolatilazation Kinetics of Gmelina, Mango, Neem and Tropical Almond Woods under Oxidative Condition

Thermogravimetric method was used to study the devolatilization characteristics and kinetics of Gmelina wood ( Gmelina arborea ), Mango wood ( Mangifera indica ), Neem wood ( Azadiracta indica ) and Tropical Almond wood ( Terminalia catappa ) under synthetic air condition at the heating rate of 30 o C/min. It was observed that all the samples followed a two-stage reaction mechanism between 200 o C and 500 o C clearly indicating regions of volatile oxidation and char combustion. The maximum rate of weight loss (%/ o C) are 2.20, 1.50, 1.25 and 1.60 for Gmelina wood, Mango wood, Neem wood and Tropical almond wood respectively and occurred at peak temperatures of 310 o C, 322 o C, 320 o C and 320 o C in the same order of sample presentation. During the oxidative stage, the activation energy of the samples, based on the Arrhenius correlation are 125,108, 142 and 113 KJ/mol respectively while during the char combustion stage the activation energy are 257, 210, 281 and 345 KJ/mol in that same order. This shows that the samples would require less energy input for their thermochemical conversion to bioenergy and would not pose any barrier to their use in combustion reactors. The samples are thus good potential feedstock among the league of biomass resources for present and future bioenergy fuels

Study on Direct Flame Solid Oxide Fuel Cell Using Flat Burner and Ethylene Flame

Solid-oxide fuel cells (SOFCs) have received significant attention due to their high efficiency, flexible fuel selection, low emissions in exhaust gases and relatively low cost. The SOFCs are also an alternative energy sources which operate at high temperature fuel cell technology [1-2]. Unlike lower temperature fuel cells, any carbon monoxide (CO) formed is transformed to carbon dioxide (CO2) at the high operating temperature, and so hydrocarbon fuels can be used directly through internal reforming or even direct oxidation. Conventional SOFCs are also excellent devices for efficient power generation. However, they are facing various challenges to overcome high cost, durability problems related to materials degradation and particularly the interconnecting and sealing materials. Single chamber SOFCs and direct flame solid oxide fuel cells (DFFCs) [3-4] are also alternative SOFC concepts that do not face the sealing problem. But the potential explosion in a single chamber SOFCs could be dangerous as a fuel oxidant mixture is fed to the high temperature fuel cell, especially if operating conditions are not well-defined. This problem can be avoided if DFFC is used where the fuel and oxidant are mixed at the point of use in a flame removing the dangerous dead of explosive mix. Besides, the DFFC provides simple cell configuration, rapid start-up and no external heater required, and it is suitable for portable applications. But the performance of the DFFC is still relatively poor, which hinders its practical applications. Therefore, the studies of DFFCs are important for designing the DFFCs for practical applications and investigating the appropriate operating conditions as well as improving the cell performance. In this study, a direct flame SOFC setup is designed and implemented based on fuel rich ethylene/air premixed flames to investigate the Ni-GDC (gadolinium-doped ceria) electrolyte supported fuel cell’s performance. The diameter of Ni-doped ceria anode and LSCF (lanthanum strontium cobalt ferrite)-GDC cathode layer is 10 mm and GDC-electrolyte is 20 mm. A flat flame burner (64 mm outer diameter) along with stainless steel stabilisation plate was used for the investigations. The stabilisation plate was placed above the burner surface and is used to stabilise the flame. The fuel cell was attached to the stabilisation plate in such a way that the anode facing to flame front and the cathode exposed to ambient air. Silver paste and wires were applied as current collectors to both sides of the fuel cells. Fig. 1 shows the schematic of the DFFC experimental setup. I-V (current-voltage), open circuit voltage (OCV), cell temperature and electrochemical impedance of the fuel cell were investigated under different operating conditions. The cell temperature was measured using a fine-wire R-type thermocouple against different ERs and distances between the burner surface and the fuel cell. The thermocouple was located 2 mm below the anode layer. The temperature was found are in the range of 628 -700 °C for the distance separations at 15 to 30 mm. It was observed that the temperature was decreased with increasing the distances. It can be explained by the fact that flame shape is largely distorted by the distance and more soot was formed in the inner flame. Relationship between OCV and cell temperature at various distances is shown in Fig. 2. Highest cell temperature and flame stability were observed for the ER of 1.52 at the distance separation 15mm. The fuel cell also exhibits an OCV of 0.84 V with the same condition. It was also found that the position of the fuel cell with respect to the flame have a significant effect on the cell temperature and the performance. The fuel cell achieved a peak power density of 41 mW/cm2 and a peak current density of 121 mA/cm2with ER at 1.52 and temperature at 700 °C. In near future different hydrocarbon fuels (e.g., methane and propane) and fuel cells can be used for the further investigations over a range of operating conditions.

Design Criteria for Future Fuels and Related Power Systems Addressing the Impacts of Non-CO2 Pollutants on Human Health and Climate Change.

Concerns over the economics, supply chain, and emissions of greenhouse gases associated with the wide use of fossil fuels have led to increasing interest in developing alternative and renewable fuels for stationary power generation and transportation systems. Although there is considerable uncertainty regarding the economic and environmental impacts of alternative and renewable fuels, there is a great need for assessment of potential and emerging fuels to guide research priorities and infrastructure investment. Likewise, there is a great need to identify potential unintended adverse impacts of new fuels and related power systems before they are widely adopted. Historically, the environmental impacts of emerging fuels and power systems have largely focused on carbon dioxide emissions, often called the carbon footprint, which is used to assess impacts on climate change. Such assessments largely ignore the large impacts of emissions of other air pollutants. Given the potential changes in emissions of air pollutants associated with the large-scale use of new and emerging fuels and power systems, there is a great need to better guide efforts to develop new fuels and power systems that can avoid unexpected adverse impacts on the environment and human health. This review covers the nature of emissions, including the key components and impacts from the use of fuels, and the design criteria for future fuels and associated power systems to assure that the non-CO2 adverse impacts of stationary power generation and transportation are minimized.

Uranium silicide pellet fabrication by powder metallurgy for accident tolerant fuel evaluation and irradiation

In collaboration with industry, Idaho National Laboratory is investigating uranium silicide for use in future light water reactor fuels as a more accident resistant alternative to uranium oxide base fuels. Specifically this project was focused on producing uranium silicide (U3Si2) pellets by conventional powder metallurgy with a density greater than 94% of the theoretical density. This work has produced a process to consistently produce pellets with the desired density through careful optimization of the process. Milling of the U3Si2 has been optimized and high phase purity U3Si2 has been successfully produced. Results are presented from sintering studies and microstructural examinations that illustrate the need for a finely ground reproducible particle size distribution in the source powder. The optimized process was used to produce pellets for the Accident Tolerant Fuel-1 irradiation experiment. The average density of these pellets was 11.54 ± 0.06 g/cm3. Additional characterization of the pellets by scanning electron microscopy and X-ray diffraction has also been performed. Pellets produced in this work have been encapsulated for irradiation, and irradiation in the Advanced Test Reactor is expected soon.

Moving Forward on Sustainable Energy Transitions: The Smart Rural Model

Among the different aspects that promote Sustainable Development, energy is a critical concern to meet the needs of present and future generations in a global-scale and long-term vision. Going beyond the emergence of local responses such as “Nearly Zero-Energy Buildings” or “Smart Cities” models, a more comprehensive view on sustainable energy planning, which involves urban and rural areas as an energetically balanced whole, has to be promoted. Central to this approach is the concept of transition which urges to be conceived in a broader and incremental change of society as pleaded by Rob Hopkins in Transition Towns. Spatial planning is able to manage the complex relationships between environment, economy and society and can represent the driver to implement integrated approaches and adaptive strategies towards the transition from “the actual fossil fuels system” to “a future net zero fossil fuels system”. This paper presents how such questions are being addressed and developed within the field of the doctoral thesis entitled “Smart Rural: energy efficiency and renewable energies in rural areas”. The interdisciplinary research design flow and expected results that support the Smart Rural model are presented in order to debate the thesis statement : “Can an integrated planning process for energy efficiency and renewable energies in rural areas, support the “Net-Zero Energy” balance at the municipal scale?” Keywords: Sustainable energy; transition towns; smart rural; energy efficiency; renewable energies; energy balance.

Thermodynamical evaluation of usefulness of future hydrocarbon fuels for use in compression ignition engines

The paper discusses the issues of the influence of the fuel spray formation on the generation of self-ignition spots and the development of pre-flame processes in the cylinder of a model diesel engine. The investigations were carried out for a standard diesel fuel and two other types of fuel that were mixtures of ethanol, butanol, and diethylether in a variety of proportions. By applying optical methods of analysis, the authors determined the geometrical indexes of the injected fuel spray as well as fuel mass distribution in the longitudinal and transverse cross section of the fuel spray during the injection process. The location and number of the self-ignition spots in the combustion chamber were evaluated on the basis of a comparison under various conditions: in presence of the charge swirl and at the lack of it. Research conducted for the single-cylinder engine confirmed the possibility of the use of diesel-like fuels for compression ignition engines.

ChemInform Abstract: Throwing New Light on the Reduction of CO2

AbstractReview: [22 refs.

FCC coprocessing oil sands heavy gas oil and canola oil. 1. Yield structure

Abstract Reducing the carbon footprint or GHG emissions is a major challenge during the production and processing of Canadian oil sands bitumen for clean transportation fuels. Co-processing bitumen derived feeds and biomass may provide an alternative solution since the level of GHG emissions for producing renewable biofuels is considered significantly lower than that for fossil fuels. In many developed countries, it is required that biofuels replace from 6% to 10% of petroleum fuels in the near future. Co-processing biomass and bitumen feeds can use existing refining infrastructure and technologies, saving capital and operating costs. In addition, co-processing may generate synergies that improve gasoline and diesel qualities. The current study investigates the catalytic cracking performances of pure heavy gas oil (HGO) derived from oil sands synthetic crude and a mixture of 15 v% canola oil in HGO using a commercial equilibrium catalyst under typical FCC conditions. Cracking experiments were performed using a bench-scale Advanced Cracking Evaluation (ACE) unit at fixed weight hourly space velocity (WHSV) of 8 h−1, 490–530 °C, and catalyst/oil ratios of 4–12 g/g. Higher conversion, dry gas yield, and liquefied petroleum gas (LPG) yield were observed at a given catalyst/oil ratio when cracking the HGO/canola oil blend compared with pure HGO. The increase in dry gas yield can be attributed to the decarboxylation and decarbonylation reactions in the presence of triglycerides composed of fatty acids in the feed, leading to the formation of CO2 and CO. In general, at a given conversion, the addition of canola oil resulted in lower gasoline yield at the expense of water formation. As well, lower coke yield was observed for the blend. The relatively high nitrogen content in the feeds played an important role in catalyst activity and selectivity, particularly at low reaction temperatures.

Throwing new light on the reduction of CO2.

While the chemical energy in fossil fuels has enabled the rapid rise of modern civilization, their utilization and accompanying anthropogenic CO2 emissions is occurring at a rate that is outpacing nature's carbon cycle. Its effect is now considered to be irreversible and this could lead to the demise of human society. This is a complex issue without a single solution, yet from the burgeoning global research activity and development in the field of CO2 capture and utilization, there is light at the end of the tunnel. In this article a couple of recent advances are illuminated. Attention is focused on the discovery of gas-phase, light-assisted heterogeneous catalytic materials and processes for CO2 photoreduction that operate at sufficiently high rates and conversion efficiencies, and under mild conditions, to open a new pathway for an energy transition from today's "fossil fuel economy" to a new and sustainable "CO2 economy". Whichever of the competing CO2 capture and utilization approaches proves to be the best way forward for the development of a future CO2-based solar fuels economy, hopefully this can occur in a period short enough to circumvent the predicted adverse consequences of greenhouse gas climate change.

Assessment of the Potential of By-Product Recovery of Thorium to Satisfy Demands of a Future Thorium Fuel Cycle

A long-standing concern about the future implementation of thorium fuel cycles has been the availability of a thorium fuel cycle infrastructure, including thorium mineral recovery. Globally, while thorium is known to be a relatively abundant element, there is currently little commercial demand for thorium, leaving many of the world’s largest thorium deposits unexploited. However, adoption and subsequent expansion of the thorium fuel cycle may not require “thorium mines” because a number of mining operations (notably titanium and uranium) already extract considerable amounts of thorium, which is presently discarded. Nearly 100000 tonnes of thorium per year could be recovered from active mine sites, with most of this coming from titanium mining (˜80000 tonnes/yr of thorium) and uranium mining (˜9000 tonnes/yr of thorium). This output would be sufficient to satisfy even the most optimistic demand for thorium resources in the near future.

An Experimental and Kinetic Modeling Study of Premixed Laminar Flames of Methyl Pentanoate and Methyl Hexanoate

Abstract Detailed chemical structures of stoichiometric and rich premixed laminar flames of methyl pentanoate and methyl hexanoate were investigated over a flat burner at 20 Torr and for methyl pentanoate at 1 atm. Molecular beam mass spectrometry was used with tunable synchrotron vacuum ultraviolet (VUV) photoionization for low pressure flames of both methyl pentanoate and methyl hexanoate, and soft electron-impact ionization was used for atmospheric pressure flames of methyl pentanoate. Mole fraction profiles of stable and intermediate species, as well as temperature profiles, were measured in the flames. A detailed chemical kinetic high temperature reaction mechanism for small alkyl ester oxidation was extended to include combustion of methyl pentanoate and methyl hexanoate, and the resulting model was used to compare computed values with experimentally measured values. Reaction pathways for both fuels were identified, with good agreement between measured and computed species profiles. Implications of these results for future studies of larger alkyl ester fuels are discussed.

Microalgae as Future Fuel: Real Opportunities and Challenges

Depleting reserves and souring prices of petroleum and oil have daunting effect on the economy of many developed and developing nations and forced researchers, government and federal agencies to opt for development of alternate fuels. In recent years, there is renewed interest in the field of algal biofuel production owing to its ability to grow in non-agriculturalable waste land and municipal wastewater/agricultural runoff water. Previous decade was attributed in developing new open culture/ reactor design for enhanced microalgal biomass production, efficient harvesting and pretreatment systems for commercial algal biofuel production. The true potential of algal biofuel spurs debate between algae experts and external observer over economics and environmental sustainability. Currently, no commercial algal energy generation system, which can surpass crop based energy content, is available. In present review, efficient culturing, operational strategies, reactor design and technological advancement in processing of algal fuel have been reviewed in graphical abstract

Production and Application of Petroleum Oil and Its Alternatives on Internal Combustion Engines

Internal combustion engines are widely used in vehicles, ships, construction machinery, and agricultural machinery due to their reliability, durability, and high efficiency. Furthermore, they will be the main powertrains for above powerplant in the next 50 years according to the wide studies. However, the development of engines is faced with some serious challenges in the future, such as the stringent emission regulations, petroleum energy supply, and greenhouse gas emissions. Therefore, we need to develop some advanced combustion technologies to reduce the pollutant emissions. Meanwhile, to prevent global warming, we need to improve the thermal efficiencies of engines and thereby reduce CO 2 emissions and save petroleum oil. Fuel properties have remarkable effects on engine performance and emissions. High-efficiency and low-emission engines must need the cooperation of high-quality fuels. Meantime, the future advanced engines may need the improved fuel properties which are different from the current gasoline or diesel fuel. In addition, the alternative biofuels have recently gained significant political and scientific interests owing to the concerns about climate change, global energy security, and petroleum supply shortage in the foreseeable future. In this special issue, firstly, N. Li et al. from State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, present the improvement on production of petroleum oil. Secondly, C. Jin and Z.Q. Zheng from Tianjin University and B. Yang et al. from Shandong University of Technology present the need for engine fuel properties for future advanced combustionmodes such as homogeneous charge compression ignition and low temperature combustion. Finally, L. Dong et al. from Civil Aviation University of China and F. Zhang et al. from Hunan University present how to achieve high-efficiency and clean combustion based on cooperated control of fuel, oil, and engines. Finally, we hope this special issue can give you some help to understand the tight relationship between petroleum and engines and to know the future engine combustion technologies and the needs for future engine fuels and oil.

Field Testing of Gas Hydrates - An Alternative to Conventional Fuels

Consumption of conventional reserves of fossil fuel has created a demand for exploring the new resources. In Current Situation it is worthwhile addressing gas hydrates as one such alternative energy resource. Methane gas hydrates have captured double amount of carbon in comparison to fossil fuels, hence they are seen as substitute to Oil and Gas sector. They are present in permafrost regions and beneath the sea. They are considered as future generation fuels. Like several other countries, India has also started a national gas hydrate programme and possible exploitation of this important natural gas resource. This review article discusses their exploitation efforts put by different countries in near past. India has recently competed National Gas Hydrate Programme NGHP-01 and started NGHP-02 recently. The paper throws light on Field Testing of gas hydrates for Alaska North Slope Site, Mallik Site, SUGAR Project, Qilan Mountain Permafrost and Nankai Trough in brief.

Creating scenarios or creating and sustaining social worlds? Towards new sociological understandings of the use and impacts of scenario planning

Many management scholars and some practitioners argue that scenario planning remains under-theorised, that it has a weak evidence base, and that, in practice, it is often too reactive. Responding to these critiques, we contribute to the development of sociologically informed scenario practices, which are more proactive (or 'transformative'). The paper is grounded in an examination of scenario practices at CSIRO (Australia's national science organisation), focused on the Future Fuels Forum, and a theory of social fields. The case illustrates that both convening a scenario exercise and the construction and/or use of scenarios can be forms of context-specific strategic action, often aimed at inducing cooperation as part of a skilled social action. It also illustrates that the impacts of scenario exercises are influenced by the fluidity of the situation and associated field-level processes; the social skill of actors and their ability to construct and use scenarios in ways that help to solve related problems; and the outcomes of political processes. We also identify key implications for practice.

Development of Low Temperature Three-Way Catalysts for Future Fuel Efficient Vehicles

Development of Low Temperature Three-Way Catalysts for Future Fuel Efficient Vehicles

The Effects of Fuel Injection Pressure and Fuel Type on the Combustion Characteristics of a Diesel Engine

In an effort to understand the effects of injection system pressure on alternative fuel performance, a single-cylinder diesel engine was outfit with a modern common rail fuel injection system and piezoelectric injector. As future new fuels will likely be used in both older mechanical injected engines as well as newer high pressure common rail engines, the question as to the sensitivity of a new fuel type across a range of engines is of concern. In this study, conventional diesel fuel (Navy NATO F76) was compared with the new Navy hydroprocessed renewable diesel (HRD) fuel from algal sources, as well as the high cetane reference fuel nC16 (n-hexadecane CN = 100). It was seen that, in general, ignition delay (IGD) was shortened for all fuels with increasing fuel injection pressure and was shortened with higher CN fuels. The combustion duration for all fuels was also significantly reduced with increasing fuel injection pressure, however, longer durations were seen for higher CN fuels at the same fuel pressure due to less premixing before the start of combustion. Companion modeling using the Lawrence Livermore National Lab (LLNL) heavy hydrocarbon and diesel primary reference fuel (PRF) chemical kinetic mechanisms for HRD and nC16 was applied to understand the relative importance of the physical and chemical delay periods of the IGD. It was seen that at low fuel injection pressures, the physical and chemical delay times are of comparable duration. However, as injection pressure increases the importance of the chemical delay times increases significantly (longer), especially with the lower CN fuel.

Combustion characteristics of premixed propane flame with added H2 and CO on a V-shaped impinging burner

The combustion characteristics of H2/C3H8/air and CO/C3H8/air premixed flames on a V-shaped burner have been investigated experimentally for future blended fuels with flow visualization, chemiluminescence and analysis of exhaust gases. The lean flammability of H2/C3H8/air is expanded to 0.38 and that of CO/C3H8/air is expanded to 0.50 on the V-shaped burner. The flame configurations, flow structures, distributions of chemiluminescence intensity of CH* and OH*, flame temperatures and CO emissions under varied mixture conditions were recorded during the combustion. Two flame configurations were observed – of types M and hill. The addition of H2 and CO to the fuel altered the flame pattern from hill-type to M-type (shorter flame) because the burning velocity, temperature and flame intensity increased with the addition of H2 and CO in the fuel. Analysis of flow visualization and chemiluminescence revealed the impinging effect, in which the collision of mixture jets decreases the main flow velocity and increases the residence time. It results in a greatly decreased leakage of the unburned mixture with accumulated heat acting as a well stirred combustible mixture for improved flame stabilization. At ɸ = 0.6, the flame temperature of H2/C3H8/air with M-type flame is 1.37 times that of CO/C3H8/air with hill-type flame, while the C3H8/air flame is extinguished. The combustion of CO that occurs in the impinging region resulted in decreased CO emissions when the addition of CO to the fuel surpassed 73.7%. These findings about the combustion characteristics, mechanisms and effects of fuel variability provide industries with an effective concept of burning blended fuels, and are applicable to syngas combustion.

Post-fire logging reduces surface woody fuels up to four decades following wildfire

Severe wildfires create pulses of dead trees that influence future fuel loads, fire behavior, and fire effects as they decay and deposit surface woody fuels. Harvesting fire-killed trees may reduce future surface woody fuels and related fire hazards, but the magnitude and timing of post-fire logging effects on woody fuels have not been fully assessed. To address this issue, we sampled surface woody fuels within 255 coniferous forest stands that burned with high fire severity in 68 wildfires between 1970 and 2007 in eastern Washington and Oregon, USA. Sampling included 96 stands that were logged after wildfire and 159 stands that were not logged. Most forest stands sampled were dominated by ponderosa pine (Pinus ponderosa) or Douglas-fir (Pseudotsuga menziesii) prior to wildfire and historically supported low and mixed-severity fire regimes. In unlogged stands, woody fuel loads were low initially, but then increased and peaked 10–20years following wildfire. In logged stands, small and medium diameter woody fuel loads peaked immediately after logging, whereas large diameter woody fuel loads peaked 10–20years after wildfire. Relative to unlogged stands, post-fire logging initially increased surface woody fuel loads, increasing small diameter fuel loads by up to 2.1Mg/ha during the first 5years after fire and increasing medium diameter fuel loads by up to 5.8Mg/ha during the first 7years after fire. Logging subsequently reduced surface woody fuel loads, reducing large diameter fuel loads by up to 53Mg/ha between 6 and 39years after wildfire, reducing medium diameter fuel loads by up to 2.4Mg/ha between 12 and 23years after wildfire, and reducing small diameter fuel loads by up to 1.4Mg/ha between 10 and 28years after wildfire. Logging also reduced rotten, large diameter fuel loads by up to 24Mg/ha between 20 and 39years after wildfire. Our study suggests that post-fire logging can significantly reduce future surface woody fuel levels in forests regenerating following wildfires. The magnitude of woody fuel reduction depends, however, on the volume and sizes of wood removed, logging methods, post-logging fuel treatments, and the amount of coarse woody debris left on-site to support wildlife habitat, erosion control, and other competing management objectives.