Future Fuels Research Articles

MID-IR laser absorption spectroscopy of 1- and 2-butanol in a shock tube facility

E-fuels are CO2-neutral fuels generated using renewable fuels such as wind and solar energy, where the carbon is taken out of the atmosphere or from biomass. One of the suitable e-fuel classes are alcohols with a low number of carbon atoms. Obtaining the low pollutant emissions on combusting liquid fuels such as fuel oil and kerosene, e-fuels with lean, premixed, pre-vaporized (LPP) concept plays a pivotal role. So, in this framework, the present work focuses on the combustion properties in the low pressure and high-temperature regime of 1- and 2-butanol isomers to evaluate their potential as future sustainable aviation fuels. The study investigates the fuel-lean conditions of 1- and 2-butanol in the fuel/oxygen equivalence ratios of 0.25, 0.5, and 0.9 relevant to the LPP (Yan et al. 2015) combustion concept for its applications in aviation. The flame chemistry of butanol isomers has been widely investigated; however, more investigations on ignition chemistry are needed. For this, tunable diode laser absorption spectroscopy is utilized to obtain the time-resolved CO formation history, ignition delay time (IDT), and progress in the butanol consumption by applying the central wavelength of 2059.91 cm−1 and 2948.27 cm−1, respectively. The measurements were performed in the temperature range of 1150–1500 K near 1.5 and 3 bar. The experimentally obtained IDT were validated with several recent reaction mechanisms available in the literature. The correlation between measured IDT, CO formation, and butanol consumption data was captured by the simulations satisfactorily. However, the CO formation from the simulation shows disagreement with the experimentally obtained signal. In addition, discrepancies in the absolute CO were observed between simulation and experiment. Moreover, a sharp drop was observed for the butanol consumption histories predominantly at ϕ= 0.9 in both 1-and 2-butanol, which could not be predicted from the available mechanisms. Furthermore, by updating the rate constants of several key reactions near the sharp fall region, a better prediction from the mechanism was seen. The time-resolved CO profile and butanol consumption history, along with the absorption cross-section data for 1- and 2-butanol isomers, are reported for the first time in this paper.

Advanced Fuel Property Data Platform: Overview and Potential Applications

This report outlines the establishment of distributed databases for management and integration of current and future aviation fuels. Aviation fuel property and performance data has been gathered for many years in public and company specific fuel surveys. These surveys are suitable for use as overall quality control information and for monitoring changes and trends in the fuels in used for flight. In recent years, significant data has been generated for alternative fuels as part of the due diligence of their approval for use through ASTM D4054, including those outside of the specification. Recently, this data, along with fundamental chemistry data has led to the creation of the Fast Track route for fuels approval when the fuel is constrained to a necessarily narrowly defined composition. The data behind these developments are often stored in a disparate, unindexed way, resulting in their underutilisation for a range of research, engineering design, specification, and in service quality control applications. To make the best use of this data, we present a scalable, Json based format for the storing of fuels data. This concept has been proposed by the Horizon 2020 Jet Fuel SCREENing and Optimization (JETSCREEN) project in conjunction with the Center of Excellence for Alternative Jet Fuels and Environment (ASCENT) programme. We have worked collaboratively to develop a joint database which currently contains data from around 30,000 conventional and 400 alternative fuels/fuel blends from a range of European and United States of America (U.S.) lead research programmes and data sources. This database can be used for a variety of purposes, both in conjunction with, or in isolation of commercially sensitive data with a greater degree of restriction. We present a number of test cases for how we see this model for data storage could be used for the benefit of all. We invite further suggestions as to how this approach could be used and welcome opportunities to work with the wider fuels community to develop this idea further.

Numerical investigation and optimization on laminar burning velocity of ammonia-based fuels based on GRI3.0 mechanism

As a carbon-free fuel, ammonia is an ideal fuel for future clean fuels, but the low combustion intensity limits the application of ammonia. The combustion performance of ammonia fuels can be effectively improved by mixing hydrogen and methane, but the mechanisms involved are different. In this study, three typical ammonia-based fuels, ammonia, ammonia-hydrogen and ammonia-methane, are numerically simulated for laminar burning velocity, and the applicability of different ammonia-based fuels mechanisms is examined and analyzed. The important reactions in the mechanisms are analyzed by sensitivity. The results show that both hydrogen and methane have a significant enhancement on ammonia fuel combustion, with hydrogen being more obvious, and the maximum laminar combustion velocity is achieved around an equivalence ratio of 1.1 for all three fuels. The reaction H + O2<=>O + OH, which is directly related to the OH radical concentration and combustion intensity, is the most sensitive reaction, while the lack of other sub-reaction mechanisms or the variation in the relative importance of the sub-reactions are the main reasons for the differences between the mechanisms. The best choice of mechanism is given with the combustion conditions. A new mechanism for laminar combustion velocity prediction of all three fuels was optimized based on the GRI3.0 mechanism, and the average error was within 10%.

Ultra-centrifugation force in adaptive evolution changes the cell structure of oleaginous yeast Trichosporon cutaneum into a favorable space for lipid accumulation.

Microbial lipid production from lignocellulose biomass provides an essential option for sustainable and carbon-neutral supply of future aviation fuels, biodiesel, as well as various food and nutrition products. Oleaginous yeast is the major microbial cell factory but its lipid-producing performance is far below the requirements of industrial application. Here we show an ultra-centrifugation fractionation in adaptive evolution (UCF) of Trichosporon cutaneum based on the minor cell density difference. The lightest cells with the maximum intracellular lipid content were isolated by ultra-centrifugation fractionation in the long-term adaptive evolution. Significant changes occurred in the cell morphology with a fragile cell wall wrapping and enlarged intracellular space (two orders of magnitude increase in cell size). Complete and coordinate assimilations of all nonglucose sugars derived from lignocellulose were triggered and fluxed into lipid synthesis. Genome mutations and significant transcriptional regulations of the genes responsible for cell structure were identified and experimentally confirmed. The obtained T. cutaneum MP11 cells achieved a high lipid production of wheat straw, approximately five-fold greater than that of the parental cells. The study provided an effective method for screening the high lipid-containing oleaginous yeast cells as well as the intracellular products accumulating cells in general.

In Situ Generated Yb2Si2O7 Environmental Barrier Coatings for Protection of Ceramic Components in the Next Generation of Gas Turbines

AbstractIn face of an accelerating climate change, the reduction and substitution of fossil fuels is crucial to decarbonize energy production. Gas turbines can operate with versatile fuel sources like natural gas and future fuels such as hydrogen and ammonia. Furthermore, thermal efficiencies above 60% can be achieved using non‐oxide silicon‐based ceramic components. However, water vapor is one of the main combustion products leading to rapid corrosion because of volatilization of the protective SiO2 layer at 1200 °C. An in situ generated Yb2Si2O7 double layered environmental barrier coating system composed of silazanes and the active fillers Yb2O3 and Si processed at 1415 °C for 5 h in air protects a Si3N4 substrate very effectively from corrosion. It exhibits a dense microstructure with a total thickness of 68 µm, overcomes 15 thermal cycling tests between 1200 and 20 °C and shows almost no mass loss after very harsh hot gas corrosion at 1200 °C for 200 h (pH2O = 0.15 atm, v = 100 m s−1). The excellent adhesion strength (36.9 ± 6.2 MPa), hardness (6.9 ± 1.6 GPa) and scratch resistance (28 N) demonstrate that the coating system is very promising for application in the next generation of gas turbines.

Investigation of Future Low-Carbon and Zero-Carbon Fuels for Marine Engines from the View of Thermodynamic and Thermal Efficiency

Investigation of Future Low-Carbon and Zero-Carbon Fuels for Marine Engines from the View of Thermodynamic and Thermal Efficiency

Cradle-Grave Energy Consumption, Greenhouse Gas and Acidification Emissions in Current and Future Fuel Cell Vehicles: Study Based on Five Hydrogen Production Methods in China

Cradle-Grave Energy Consumption, Greenhouse Gas and Acidification Emissions in Current and Future Fuel Cell Vehicles: Study Based on Five Hydrogen Production Methods in China

Prospect of Renewable Energy due to COVID-19 and Opportunity for Transition to Future Fuels

enewable energy is the energy of the future because it is the best long-term alternative for fossil fuels, which are facing numerous issues, particularly from an environmental standpoint. The world has established a number of targets to address the issues posed by the conventional energy sector. The United Nations has set 17 Sustainable Development Goals (SDGs) to be achieved by 2030; previously, many countries were not on track to meet these goals; however, the Covid-19 pandemic, which not only affected people's health, but also the energy sector, has demonstrated how quickly we are accustomed to change and can respond quickly and collectively with a common goal. As a result, the focus of this article is on the COVID-19's influence on the RE industry and its implications for future greener fuels. We talked about the opportunities that have arisen as a result of the COVID-19 situation that can help with the shift to alternative fuels. Finally, the problems and opportunities facing the creation of more environmentally friendly transportation fuels are identified.

Cell Wall Compositions of Sorghum bicolor Leaves and Roots Remain Relatively Constant Under Drought Conditions.

Renewable fuels are needed to replace fossil fuels in the immediate future. Lignocellulosic bioenergy crops provide a renewable alternative that sequesters atmospheric carbon. To prevent displacement of food crops, it would be advantageous to grow biofuel crops on marginal lands. These lands will likely face more frequent and extreme drought conditions than conventional agricultural land, so it is crucial to see how proposed bioenergy crops fare under these conditions and how that may affect lignocellulosic biomass composition and saccharification properties. We found that while drought impacts the plant cell wall of Sorghum bicolor differently according to tissue and timing of drought induction, drought-induced cell wall compositional modifications are relatively minor and produce no negative effect on biomass conversion. This contrasts with the cell wall-related transcriptome, which had a varied range of highly variable genes (HVGs) within four cell wall-related GO categories, depending on the tissues surveyed and time of drought induction. Further, many HVGs had expression changes in which putative impacts were not seen in the physical cell wall or which were in opposition to their putative impacts. Interestingly, most pre-flowering drought-induced cell wall changes occurred in the leaf, with matrix and lignin compositional changes that did not persist after recovery from drought. Most measurable physical post-flowering cell wall changes occurred in the root, affecting mainly polysaccharide composition and cross-linking. This study couples transcriptomics to cell wall chemical analyses of a C4 grass experiencing progressive and differing drought stresses in the field. As such, we can analyze the cell wall-specific response to agriculturally relevant drought stresses on the transcriptomic level and see whether those changes translate to compositional or biomass conversion differences. Our results bolster the conclusion that drought stress does not substantially affect the cell wall composition of specific aerial and subterranean biomass nor impede enzymatic hydrolysis of leaf biomass, a positive result for biorefinery processes. Coupled with previously reported results on the root microbiome and rhizosphere and whole transcriptome analyses of this study, we can formulate and test hypotheses on individual gene candidates’ function in mediating drought stress in the grass cell wall, as demonstrated in sorghum.

Rewiring cyanobacterial photosynthesis by the implementation of an oxygen-tolerant hydrogenase

Molecular hydrogen (H2) is considered as an ideal energy carrier to replace fossil fuels in future. Biotechnological H2 production driven by oxygenic photosynthesis appears highly promising, as biocatalyst and H2 syntheses rely mainly on light, water, and CO2 and not on rare metals. This biological process requires coupling of the photosynthetic water oxidizing apparatus to a H2-producing hydrogenase. However, this strategy is impeded by the simultaneous release of oxygen (O2) which is a strong inhibitor of most hydrogenases. Here, we addressed this challenge, by the introduction of an O2-tolerant hydrogenase into phototrophic bacteria, namely the cyanobacterial model strain Synechocystis sp. PCC 6803. To this end, the gene cluster encoding the soluble, O2-tolerant, and NAD(H)-dependent hydrogenase from Ralstonia eutropha (ReSH) was functionally transferred to a Synechocystis strain featuring a knockout of the native O2 sensitive hydrogenase. Intriguingly, photosynthetically active cells produced the O2 tolerant ReSH, and activity was confirmed in vitro and in vivo. Further, ReSH enabled the constructed strain Syn_ReSH+ to utilize H2 as sole electron source to fix CO2. Syn_ReSH+ also was able to produce H2 under dark fermentative conditions as well as in presence of light, under conditions fostering intracellular NADH excess. These findings highlight a high level of interconnection between ReSH and cyanobacterial redox metabolism. This study lays a foundation for further engineering, e.g., of electron transfer to ReSH via NADPH or ferredoxin, to finally enable photosynthesis-driven H2 production.

Analysis of Auto-Ignition Chemistry in Aeroderivative Premixers at Engine Conditions

Abstract The minimization of auto-ignition risk is critical to the design of premixers of high power aeroderivative gas turbines as an increased use of highly reactive future fuels (for example, hydrogen or higher hydrocarbons) is anticipated. Safety factors based on ignition delays of homogeneous mixtures are generally used to guide the choice of a residence time for a given premixer. However, auto-ignition chemistry under aeroderivative conditions is fast (0.5–2 ms) and can be initiated within typical premixer residence times. The analysis of what takes place in this short period necessarily involves the study of low-temperature auto-ignition precursor chemistry, but precursors can change with fuel and local reactivity. Chemical explosive modes (CEMs) are a natural alternative to study this as they can provide a measure for auto-ignition risk by considering the whole thermochemical state in the framework of an eigenvalue problem. When transport effects are included by coupling the evolution of the chemical explosive modes to turbulence, it is possible to obtain a measure of spatial auto-ignition risk where both chemical (e.g., ignition delay) and aerodynamic (e.g., local residence time) influences are unified. In this article, we describe a method that couples large eddy simulation (LES) to newly developed, reduced auto-ignition chemical kinetics to study auto-ignition precursors in an example premixer representative of real life geometric complexity. A blend of pure methane and di-methyl ether (DME), a common fuel used for experimental auto-ignition studies, was transported using the reduced mechanism (38 species/238 reactions) under engine conditions at increasing levels of DME concentrations until exothermic auto-ignition kernels were formed. The resolution of species profiles was ensured by using a thickened flame model where dynamic thickening was carried out with a flame sensor modified to work with multistage heat release. This paper is outlined as follows: First, a reduced mechanism is constructed and validated for modeling methane as well as DME auto-ignition. Second, sensitivity analysis is used to show the need for chemical explosive modes. Third, the thickened flame model modifications are described and then applied to an example premixer at 25 bar/890 K preheat. The chemical explosive mode analysis closely follows the large thermochemical changes in the premixer as a function of DME concentrations and identifies where the premixer is sensitive and flame anchoring is likely to occur.

Noble Metal-Free Hierarchical ZrY Zeolite Efficient for Hydrogenation of Biomass-Derived Levulinic Acid.

Developing a low-cost and robust catalyst for efficient transformation of biomass-derived platform chemicals plays a crucial role in the synthesis of future transportation fuels. Herein, a post-synthetic strategy was employed to develop a noble metal-free and robust ZrY zeolite catalyst, which is efficient for the hydrogenation of biomass-derived levulinic acid (LA) into biofuel γ-valerolactone (GVL), whereas over 95% yield of GVL was achieved in 10 h at 220°C. The effects of acidic properties from ZrY catalysts and various reaction parameters on the catalytic performance were then discussed in detail. Subsequently, different characterization tools were used to compare the difference and relationship of structure activity between the fresh and spent ZrY catalysts. It was found that acidity and the metal–support interaction were important for the direct synthesis of GVL. This work provides a guideline to design a noble metal-free catalyst for high-value utilization of biomass-derived sources.

Effective indicators of a hydrogen engine operating on a lean mixture and equipped with a modified fuel supply system

Introduction (problem statement and relevance). Limited oil reserves and tightening environmental standards are forcing engine manufacturers to switch to alternative fuels in the near future, among which hydrogen is the most promising. The advantages of hydrogen are high specific heat of combustion and high combustion rate. Wide concentration limits of hydrogen combustion make it possible to use high-quality power control, thereby providing an increase in the efficiency of a hydrogen engine when compared to the basic internal combustion engine.The purpose of the study was to ensure the operation of a serial gasoline engine running on hydrogen with a new experimental fuel supply system, as well as the modification of the intake manifold design without abnormal phenomena during combustion when operating on a lean mixture, and to obtain efficient and ecological characteristics of a hydrogen engine under bench test conditions, as a result.Methodology and research methods. The work is experimental, the reliability of the results obtained is confirmed by the use of modern means for measuring and processing experimental data. The obtained results of measuring nitrogen oxides are adequate to the known Zel'dovich thermal mechanism. The value of the results lies in the fact that they show the feasibility of transferring serial internal combustion engines to hydrogen; in addition, these results are used to develop and verify mathematical 3D models of the hydrogen engine working process.Scientific novelty and results. A new system providing the necessary characteristics (pressure, duration and cycle dose) for supplying hydrogen to the intake system with two injectors for each cylinder was designed, installed and tested on the prototype engine.Practical significance. The expediency of the working cycle creation and efficiency of a hydrogen engine with an experimental lean-burn fuel supply system was confirmed, which made it possible to provide high-quality power control with external mixture formation and forced ignition.

Low-carbon scenarios for long-distance travel 2060

In many industrialised countries, the climate impact from long-distance travel is greater than that from short-distance travel. In this paper, we present five scenarios for long-distance travel in 2060, which are consistent with a 67% probability of limiting global warming to 1.8 degrees. The scenarios concern travel by the Swedish population, but per capita travel volume and fuel use could be generalised globally. A key result is that all scenarios require reductions in Swedish per capita air travel in the range of 38–59% compared to 2017. The direct effect on air travel of implementing a high-speed rail network in Sweden and Northern Europe was found to be modest. A higher emission reduction could be achieved if mixed mode trips comprising rail and air legs were more widely adopted. Finally, the pros and cons of future aviation fuels are discussed, the main candidates being biofuel, electrofuel, and liquid hydrogen.

A Comprehensive Review of Nuclear-Renewable Hybrid Energy Systems: Status, Operation, Configuration, Benefit, and Feasibility

One of the biggest concerns of the present century is energy security and climate change. Further, studies suggest that there would be a huge lack of fossil fuels in near future. Moreover, in terms of cleaner production, the most popular and practiced way of power generation is renewable energy sources which are intermittent in nature, require large land area, and also dependent on geographic positions and climatic conditions. Besides, nuclear energy is also having some limitations including government policies and public apprehensions. To overcome these hurdles, these two carbon-free technologies can be integrated and form a nuclear-renewable hybrid energy system (N-R-HES). Literature related to the proposed systems is extremely rare and the systems are not yet well-developed. Keeping that into concern, this paper discusses the operation, status, prospects, and benefits of N-R-HES. Various possible integration techniques along with their operation are discussed in detail. Moreover, six aspects of interconnections are identified: electrical, thermal, chemical, mechanical, hydrogen, and information. The paper also discusses the reactor licensing, permitting procedures along the different benefits of N-R-HES. Additionally, research limitations and needs are identified for further exploration of the topic throughout the paper.

Tribological Performance of Biomass-Derived Bio-Alcohol and Bio-Ketone Fuels

This study relates to developing future alternative fuels and focuses on the effects of a fuel’s molecular structure on its properties and performance in advanced propulsion systems. The tribological performance of various biomass-derived oxygenated alternative fuels, including butanol, pentanol, cyclopentanol, cyclopentanone, and gasoline and their blends with diesel, was investigated. Lubricity tests were conducted using a high-frequency reciprocating rig (HFRR). Cyclopentanone-diesel and cyclopentanol-diesel blends result in smaller wear scar sizes compared to using their neat forms. A lower steel disc contaminated with the alternative fuels during the HFRR tests resulted in worn surface roughness values lower than those of the neat diesel by up to 20%. It is believed that these reductions are mainly due to the presence of the hydroxyl group and the carbonyl group in alcohols and ketones, respectively, which make them more polar and consequently helps the formation of the protective lubrication film on the worn moving surfaces during the sliding process. Overall, the results from this study indicate that environmentally friendly cyclopentanol and cyclopentanone are practical and efficient fuel candidates for future advanced propulsion systems.

Thermodynamic Analysis of an Ammonia Fueled SOFC System for Maritime Applications

Transporting goods around the world with ships is nowadays the most cost-effective solution and due to this reason, more than four-fifths of the entire global trade by volume is carried out by sea. This leads to the estimation concerning emissions of the International Maritime Organization (IMO), that international shipping was in 2014 responsible for 2,2% of global annual CO2 emissions and that these emissions could increase between 50% and 250% by 2050. Besides the CO2 and greenhouse gas (CHG) emissions ships, which are conventionally fueled with heavy fuel oil (HFO) or marine diesel oil (MDO), also emit nitrogen oxides (NOx) and sulphur oxides (SOx). These emissions and especially the SOx emissions are regulated by the IMO in the International Convention for the Prevention of Pollution from Ships (MARPOL: Annexe VI). Because of these regulations and more stringent self-imposed targets of several nations and organizations, the demand for alternative fuels and propulsion systems for the maritime transport sector is increased significantly. [1] [2] [6]In order to meet these and more stringent upcoming regulations, ammonia, which can be produced by renewable energy sources (green ammonia), is proposed as a potential fuel for the maritime transport sector. Beside the fact, that green ammonia would lead to no CO2 emissions, ammonia in relation to other renewable fuels can be seen as a balanced solution concerning the volumetric energy density and renewable synthetic production cost. Moreover, ammonia is advantageous compared to hydrogen, because of its lower cost per unit of stored energy, more widespread production, handling and distribution capacity and better commercial viability. But there are also some concerns and challenges for the application of ammonia as a ship fuel, namely the toxicity and the environmental impact. Therefore, some safety measures have to be established like shut-off valves in case of leakage and redundancy in the fuel supply line. Furthermore, one big concern of ammonia is the relative low efficiency value of the corresponding efficiency chain, when ammonia is produced via Haber-Bosch process, because of the production of the hydrogen as a basis for this process. For this reason, also the direct production of ammonia via proton ceramic electrolysis will be reviewed. [2] [3] [4] [6]Because of the fact, that ammonia is not as practicable for any ship type, the load points for the simulation of the investigated propulsion systems are also described in this paper. Research shows, that ammonia as a fuel for container ships and bulk carrier is the most useful way of application. [3] [5]For further investigations, the solid oxid fuel cell (SOFC) is chosen as the basis propulsion for the ship, because of the possible direct use of ammonia and its good efficiency compared to other systems namely internal combustion engine (ICE) or PEMFC. In detail, the aim is, to investigate by simulation (Matlab/Simulink) three possible solid oxide fuel cell (SOFC) architectures, which are fueled with ammonia, and to compare their thermodynamic efficiency for marine applications representative operation points. The simulation output is used to answer the main research question: [3] How thermodynamically efficient are different SOFC system architectures for marine applications powered by ammonia? An Outlook on testing of a 5 kW Lab System is presented to validate the simulative results.[1] Serra, Patrizia; Fancello, Gianfranco: Towards the IMO’s GHG Goals: A Critical Overview of the Perspectives and Challenges of the Main Options for Decarbonizing International Shipping. University of Cagliari, DICAAR—Department of Civil and Environmental Engineering and Architecture, April 2020[2] McKinlay, Charlie; Hudson, Dominic Antony; Turnock, Stephen: A Comparison of Hydrogen and Ammonia for Future Long Distance Shipping Fuels. IN: LNG/LPG and Alternative Fuels, 29th – 30th January 2020, London, UK[3] de Vries, Niels: Safe and effective application of ammonia as a marine fuel. Master thesis, TU Delft and C-Job & Partners B.V. 2019[4] Valera-Medina, Agustin; Xiao, Hua; Owen-Jones, Martin; David, Bill et al.: Ammonia for power. IN: Progress in Energy and Combustion Science 69, p.63-102, september 2018[5] Kim, Kyunghwa; Roh, Gilltae; Kim, Wook; Chun, Kangwoo: A Preliminary Study on an Alternative Ship Propulsion System Fueled by Ammonia: Environmental and Economic Assessments. In: Journal of Marine Science and Engineering. March 2020[6] Hansson, Julia; Brynolf, Selma; Fridell, Erik; Lehtveer, Mariliis: The Potential Role of Ammonia as Marine Fuel—Based on Energy Systems Modeling and Multi-Criteria Decision Analysis. IN: sustainability, April 2020

A comprehensive review on the application of bioethanol/biodiesel in direct injection engines and consequential environmental impact

Bioethanol/biodiesel are deemed a highly suitable alternative to conventional fuels in the near future due to their versatility in production techniques and operability. This paper examines the engine performance and possible scope of improvement in direct injection engines powered by biofuel blends. The obtained outcomes from this review are mainly focused on three distinguished fuel properties: fuel feasibility, emissions, and engine performance. Critical analysis of these factors is followed by the highlighting of the possible scope of improvement. This review indicates that biofuels perform best with additives or as an additive when used with traditional petroleum fuels. Research analysis indicates that biodiesels show significant improvement in ignition delay due to higher oxygen content compared with traditional petroleum fuels and produce lower emission of pollutant gas. However, engines have shown a decrease in performance regarding power output, torque, and fuel efficiency. The suggested improvement to counter these issues include the addition of nanoparticles, exhaust gas recirculation, ethanol/methanol fumigation, and introduction of various methyl esters into the mixture.

The Fuel of Future: Hydrogen and Reduction Products of Carbon Dioxide

The Fuel of Future: Hydrogen and Reduction Products of Carbon Dioxide

Synthetic Fuels Based on Dimethyl Ether as a Future Non-Fossil Fuel for Road Transport From Sustainable Feedstocks

In this review we consider the important future of the synthetic fuel, dimethyl ether (DME). We compare DME to two alternatives [oxymethylene ether (OMEx) and synthetic diesel through Fischer-Tropsch (FT) reactions]. Finally, we explore a range of methodologies and processes for the synthesis of DME.DME is an alternative diesel fuel for use in compression ignition (CI) engines and may be produced from a range of waste feedstocks, thereby avoiding new fossil carbon from entering the supply chain. DME is characterised by low CO2, low NOx and low particulate matter (PM) emissions. Its high cetane number means it can be used in CI engines with minimal modifications. The key to creating a circular fuels economy is integrating multiple waste streams into an economically and environmentally sustainable supply chain. Therefore, we also consider the availability and nature of low-carbon fuels and hydrogen production. Reliable carbon dioxide sources are also essential if CO2 utilisation processes are to become commercially viable. The location of DME plants will depend on the local ecosystems and ideally should be co-located on or near waste emitters and low-carbon energy sources. Alternative liquid fuels are considered interesting in the medium term, while renewable electricity and hydrogen are considered as reliable long-term solutions for the future transport sector. DME may be considered as a circular hydrogen carrier which will also be able to store energy for use at times of low renewable power generation.The chemistry of the individual steps within the supply chain is generally well known and usually relies on the use of cheap and Earth-abundant metal catalysts. The thermodynamics of these processes are also well-characterised. So overcoming the challenge now relies on the expertise of chemical engineers to put the fundamentals into commercial practice. It is important that a whole systems approach is adopted as interventions can have detrimental unintended consequences unless close monitoring is applied. This review shows that while DME production has been achieved and shows great promise, there is considerable effort needed if we are to reach true net zero emissions in the transport sector, particularly long-haul road use, in the require timescales.