Synthetic Fuels Research Articles

Spray Momentum Flux Novel Estimation Procedure through the Fuel Rate of Injection Using Hydrogenated Fuels with Single Hole Nozzle Diesel Injector.

Sustainable means of transport require the innovation or development of propulsive systems more respectful of the environment. Despite current criticism, modern compression-ignition engines are efficient alternatives also in light aviation and surveillance drones (such as small helicopters), as means of air transport. Currently, the improvement of the injection, air-fuel mixture formation, and combustion processes using sustainable synthetic fuels, produced from renewable raw materials or by carbon dioxide capture, is a reality. For improving the air-fuel mixture formation inside the combustion chamber, one of the key parameters is knowledge of the spray momentum flux because of its effect on the air entrainement. To measure this parameter is complex. However, the experimental determination of the fuel mass flow rate is a common procedure. The objective of this work is the proposal of a novel but robust methodology for the momentum flux estimation of fuel sprays from measurement of the rate of injection. In this work, single-hole nozzles of 115, 130, and 150 μm in diameter are studied. The implemented methodology is applied to three fuels: a diesel fuel without biodiesel, used as reference, and two sustainable synthetic fuels: a gas to liquid fuel and a hydrotreated vegetable oil. With the fuel injection rates and the simple model proposed, the spray momentum flux is estimated under different operating conditions of a common-rail injection system. The results of the spray momentum flux show a very good precision compared with those experimentally and previously obtained with similar fuels but with multihole nozzle. With the method proposed in this work, an adequate forecast of spray momentum flux is obtained in the case of not having an experimental setup that allows direct measurement of the momentum flux. This study can help investigators for fuel spray modeling with novel and renewable fuels in modern propulsive systems.

Driving mechanisms of high-cetane number, synthetic fuel autoignition: The case of OME[formula omitted

Oxymethylene dimethyl ethers (CH3O(CH2O)xCH3 or OMEx) are potential synthetic substitutes of diesel and jet fuel that can be acquired through CO2 recycling and have the unique “clean” feature that they do not contain C-C bonds in their atom chain, but only C-O, and therefore can combust without soot. Also, they present favourable ignition characteristics and high cetane numbers. In order to determine ignition control strategies, the dominant oxidation pathways must be identified. To this end, autoignition of OME2−4/air mixtures is studied using the tools of Computational Singular Perturbation algorithm. It is shown that as the length of the atom chain x increases, ignition delays become shorter. This is because, at the very early stages of the process, H-abstraction and fuel break-up reactions realize in a larger number of ways for larger x. The process develops first through a chemical runaway that tends to slow-down autoignition and then through a thermal runaway that tends to speed-up autoignition at a progressively stronger rate. It is shown that the total heat release is independent of x, although the ignition delay becomes shorter with increasing x. The two stable intermediates H2O2 and CH2O are shown to shorten ignition delays, when used as additives in the initial mixtures. It is demonstrated that OMEx synthetic fuels offer the capability of soot-less combustion, combined with ignition control.

The race between hydrogen and heat pumps for space and water heating: A model-based scenario analysis

This paper analyses different levels and means of the electrification of space and hot water heating using an explorative modelling approach. The analysis provides guidance to the ongoing discussion on favourable pathways for heating buildings and the role of secondary energy carriers such as hydrogen or synthetic fuels. In total, 12 different scenarios were modelled with decarbonisation pathways until 2050, which cover all 27 member states of the European Union. Two highly detailed optimisation models were combined to cover the building stock and the upstream energy supply sector. The analysis shows that decarbonisation pathways for space and water heating based on large shares of heat pumps have at least 11% lower system costs in 2050 than pathways with large shares of hydrogen or synthetic fuels. This translates into system cost savings of around €70 bn. Heat pumps are cost-efficient in decentralised systems and in centralised district heating systems. Hence, heat pumps should be the favoured option to achieve a cost-optimal solution for heating buildings. Accordingly, the paper makes a novel and significant contribution to understanding suitable and cost-efficient decarbonisation pathways for space and hot water heating via electrification. The results of the paper can provide robust guidance for policymakers.

Unlocking the potential of synthetic fuel production: Coupled optimization of heat exchanger network and operating parameters of a 1 MW power-to-liquid plant

The use of synthetic fuels is a promising way to reduce emissions significantly. To accelerate cost-effective large-scale synthetic fuel deployment, we optimize a novel 1 MW power-to-liquid (PtL) plant in terms of PtL-efficiency and fuel production costs. For numerous plants, the available waste heat and temperature level depend on the operating point. To optimize efficiency and costs, the choice of the operating point is included in the heat exchanger network synthesis. All nonlinearities are approximated using piecewise linear models and transferred to MILP. Adapting the epsilon constraint method allows us to solve the multi-criteria problem with uniformly distributed solutions on the Pareto front. We improved the lowest production costs of 1.89 €/kg and the highest efficiency of 58.08% from the conventional design process to 1.83 €/kg and 61.33%. By applying the presented method, climate-neutral synthetic fuels can be promoted and emissions can be reduced in the long term.

Control strategy of solid oxide electrolysis cell operating temperature under real fluctuating renewable power

Power-to-liquid (PtL) technology through solid oxide electrolysis cells (SOECs) can efficiently convert renewable energy sources into synthetic fuels for long-time energy storage. However, due to its fluctuation and intermittence, renewable energy sources only produce time-varying currents, which directly impact the operating temperature of SOEC, generating high thermal stresses for SOEC and reducing its durability. To deal with this issue, a control-oriented SOEC dynamic model containing an electrochemical part, a reversible water gas shift (RWGS) part, and a thermodynamic part, was developed in this paper. Afterward, main control parameters, able to adjust SOEC operating temperature effectively, were determined through the Extended Fourier Amplitude Sensitivity Test (EFAST). The corresponding results show that the air flow rate was the best choice to control SOEC temperature when it works in a low current density case, while the fuel flow rate becomes optimal when SOEC operates in a high current case. Given this knowledge, an adaptive feedback control strategy was proposed to stabilize the operating temperature of SOEC in practice. In the end, the effectiveness of the proposed control was demonstrated through step signals of current in both low- and high-current density cases and an actual fluctuating current from real solar cells.

OBTAINING UNSATURATED HYDROCARBONS FROM COAL

The article is devoted to the improvement of the technology of obtaining Liquid Motor Fuels from Coal. Unsaturated hydrocarbons are the most important chemical raw material products and are widely used for producing polymers, alcohols and some other organic substances. The paper considers the proposition of technological process of obtaining Synthetic Fuel from Coal with a positive yield effect of the final product with high quality. It is possible to organize the production of Liquid Fuel is made of Coal conversion. The method of Coal conversion into Liquid Motor Fuel is its gasification and hydrogenation but this is not the only way out. The paper proposes the possibility of creating the small plants for the production of synthetic fuels and components of organic synthesis, which can be used of the capacity of metallurgical factories and shops of machine-building enterprises that are vacated areas. In modern society the need is growing to use alternative liquid fuel technologies, for example, by indirect liquefaction of coal. This is especially important for Ukraine during and after hostilities. Ukraine does not have sufficient oil and gas reserves, but it has coal deposits in the coal basin in the west of the country.
 An important aspect that is insisted on is the achievement of energy independence. Given the historical traditions and the existing structure of energy deposits in Ukraine, one of the ways to solve this strategic task should be the development of the coal industry. In addition, the environmental component of each of these types of security can be an integrator that integrates them into the national security system. This will help to find their optimal ratio in this system. Moreover, today there is no doubt that any aspect of national security, whether economic, technological or defense, loses its meaning in the event of unfitness of the environment for human life and activity. An influential factor in increasing production of coal for processing in the western part of Ukraine is the maximum extraction of coal reserves and at the same time protection of subsoil.

Validation of a Generic Non-Swirled Multi-Fuel Burner for the Measurement of Flame Stability Limits for Research of Advanced Sustainable Aviation Fuels

Future aviation concepts should be both CO2-neutral and without other emissions. One approach to reaching both targets is based on sustainably produced synthetic liquid fuels, which may allow very clean, lean premixed prevaporized (LPP) combustion. For that, fuels are needed with much longer ignition delay times and a lower flashback propensity than current jet fuels. We describe an experimental setup to investigate the flashback stability of liquid fuels in a multi-fuel burner. In this work, the measurement procedure and the determination of the experimentally obtained accuracy are in focus with regard to prevaporized and preheated iso-propanol/air flames in an equivalence ratio range of 0.85 to 1.05 involving three preheating levels (573, 673, and 773 K). As the determination of the accurate unburnt gas temperature just ahead of the flame is of strong importance for flashback but not directly possible, a model is implemented to determine it from the measurable quantities. Even with this indirect method, and also regarding the hysteresis of the experimental preheating temperature, it is found that the relevant quantities, namely, measured temperatures, mass flows, and values derived from them, can be determined with accuracy in the range below 1.7%.

Dewatering of mixtures containing formaldehyde, methanol, water, and poly(oxymethylene) dimethyl ethers by pervaporation: Membrane screening and mini-plant operation

Poly(oxymethylene) dimethyl ethers of chain lengths n = 3 to 5 (OME3−5) are clean-burning synthetic diesel fuels capable of utilizing biomass and captured carbon dioxide as raw materials. In water-tolerant OME3−5 production processes, separating water from mixtures containing methanol, formaldehyde, water, and short-chain OME1−2 is a critical and challenging task. This work focuses on the screening of membranes for water separation from such mixtures, particularly emphasizing their selectivity towards water and stability. Among the materials investigated, a ceramic SiO2 membrane was identified as promising. Fourteen pervaporation experiments were conducted on a continuous setup at a mini-plant scale. No deterioration in flux or permeate quality was observed across the repeated experiments. The membrane exhibited significant separation factors for all components, demonstrating its selectivity for water. However, the selectivity towards water decreased for the mini-plant experiments compared to the screening experiments. A model describing the water flux as a function of the water concentration in the feed was developed, demonstrating accurate characterization of the operation dynamics. These outcomes establish the fundamental feasibility of water separation via pervaporation using SiO2 membranes in water-tolerant OME3−5 production processes.

Obtaining the Synthetic Fuels from Waste Plastic and Their Effect on Cavitation Formation in a Common-Rail Diesel Injector

The presented paper addresses two significant issues of the present time. In general, the studies of the effect of synthetic fuels on cavitation formation and cavitation erosion prediction in the nozzle tip of common-rail diesel injectors were addressed. The first problem is plastic waste, which can have a significant negative environmental impact if not treated properly. Most plastic waste has high energy value, so it represents valuable material that can be used in resource recovery to produce various materials. One possible product is synthetic fuel, which can be produced using thermal and catalytic pyrolysis processes. The first issue addressed in the presented paper is the determination of fuel properties since they highly influence the fuel injection process, spray development, combustion, etc. The second is the prediction of cavitation development and cavitation erosion in a common-rail diesel injector when using pyrolytic oils from waste plastic. At first, pyrolytic oils from waste high- and low-density polyethylene were obtained using thermal and catalytic pyrolysis processes. Then, the obtained oils were further characterised. Finally, the properties of the obtained oils were implemented in the ANSYS FLUENT computational program and used in the study of the cavitation phenomena inside an injection nozzle hole. The cavitating flow in FLUENT was calculated using the Mixture Model and Zwart-Gerber-Belamri cavitation model. For the modelling of turbulence, a realisable k–ε model with Enhanced Wall Treatment was used, and an erosion risk indicator was chosen to compare predicted locations of cavitation erosion. The results indicate that the properties of the obtained pyrolytic oils have slightly lower density, surface tension and kinematic viscosity compared to conventional diesel fuel, but these minor differences influence the cavitation phenomenon inside the injection hole. The occurrence of cavitation is advanced when pyrolytic oils are used, and the length of cavitation structures is greater. This further influences the shift of the area of cavitation erosion prediction closer to the nozzle exit and increases its magnitude up to 26% compared to diesel fuel. All these differences have the potential to further influence the spray break-up process, combustion process and emission formation inside the combustion chamber.

Nuclear hydrogen projects to support clean energy transition: Updates on international initiatives and IAEA activities

Hydrogen is expected to be a game changer in the fight against climate change, being able to support the clean energy transition through a variety of roles: decarbonizing different hard-to-abate industrial sectors (such as steel, cement production) and transport (in long haul vehicles, maritime transport, and aviation), direct use as a fuel, chemical feedstock or in the form of synthetic fuels, and providing the ability to integrate with hybrid energy systems and renewables, enhancing energy storage and tapping the full potential of renewable energy sources. As a consequence, a substantial expansion in hydrogen production, due to rise in the demand, is expected by 2050, with all the generation coming from zero-carbon processes (electrolysis/thermochemical cycles using clean electricity and heat) or from a low-carbon production process using steam methane reforming with carbon capture and storage. Nuclear energy can be capitalized on both electricity and heat to provide a clean and reliable source of hydrogen through various processes. There are currently various demonstration projects undergoing in several countries to showcase the use of nuclear energy to produce clean hydrogen, considering both the current reactor fleet and advanced reactors. This paper provides an overview of these projects, giving an insight on the potential use of nuclear energy for hydrogen production and the current status of existing projects. It also highlights the activities of the International Atomic Energy Agency on technical and economic assessment of hydrogen production using nuclear energy for near term deployment.

Decarbonization of Former Lignite Regions with Renewable Hydrogen: The Western Macedonia Case

For lignite intense regions such as the case of Western Macedonia (WM), the production and utilization of green hydrogen is one of the most viable ways to achieve near zero emissions in sectors like transport, chemicals, heat and energy production, synthetic fuels, etc. However, the implementation of each technology that is available to a respective sector differs significantly in terms of readiness and the current installation scale of each technology. The goal of this study is the provision of a transition roadmap for a decarbonized future for the WM region through utilizing green hydrogen. The technologies which can take part in this transition are presented, along with the implementation purpose of each technology, and the reasonable extension that each technology could be adopted in the present context. The WM region’s limited capacity for green hydrogen production leads to certain integration scenarios, with regards to the required hydrogen, electrolyzer capacities, and required power, whereas an environmental assessment is also presented for each scenario.

Comparison of fuel properties of alternative drop-in fuels with standard marine diesel and the effects of their blends

Drop-in fuels are biofuels or synthetic fuels designated to be blended with conventional petroleum-derived hydrocarbons. These alternative fuel blends can be used without major modifications of the engine or the fuel system. Thus, the use of drop-in fuels offers the marine sector a good first opportunity to reduce the carbon footprint and other emissions. This work investigates the miscibility and compatibility of different potential drop-in fuels with standard distillate marine diesel in order to provide an initial outlook on possible use in the maritime sector based on their fuel characteristics. The five drop-in fuels Fatty acid methyl esters (FAME), Oxymethylene ether (OME), Hydrotreated vegetable oils (HVO), Fischer-Tropsch diesel (FTD) and a pyrolysis oil (HDO) were mixed at 10, 30 and 50 % with standard marine distillate diesel and the physical and chemical properties, the distillation curves and the corrosion stability as well as the storability were analysed. All drop-in fuels can be blended with DMA. Due to the chemically different composition of OME, the distillation curve of the blends significantly differs from the distillation curve of DMA, which should be taken into consideration when using these new alternative blends. Furthermore, the blends of OME and FTD show an unexpected corrosion, which is not observed in the pure drop-in fuels. This is expected to have a considerable influence on the engine operation as well as on the storage.

Blending Hydrogen With Natural Gas/Biomethane and Transportation in Existing Gas Networks

Abstract The existing European Union (EU) natural gas network provides large capacity to integrate renewable (RGs) and low-carbon gases. Today, hydrogen contributes only a few percent to Europe’s energy consumption and is almost exclusively produced from fossil fuels and used in the industry. Nevertheless, hydrogen has a significant role to play in emission reduction in hard-to-decarbonize sectors, in particular, as a fuel in transport applications and as a fuel or feedstock in certain industrial processes (steel, refining or chemical industries, the production of “green fertilizers”). Carbon dioxide (CO2) in reaction with hydrogen can also be further processed into synthetic fuels, such as synthetic kerosene in aviation. In addition, hydrogen brings other environmental co-benefits when used as fuel, such as the lack of air pollutant emissions. However, in transitional phase from fossil to RG, namely, renewable or green hydrogen, natural gas/biomethane and hydrogen blends, are needed to gradually replace natural in existing gas transmission and distribution networks. The gas networks are believed to be able to use natural gas/biomethane and hydrogen blends with 5–20 % of hydrogen by volume. Most systems and applications are able to handle it without a need for major infrastructure upgrades or end-use appliance retrofits or replacements. The promotion of hydrogen network such as European Hydrogen backbone (EHB) is gaining momentum in Europe. To decarbonize the natural gas grids, the threshold of hydrogen in the existing grid systems must be increased, which can be done by means of wider natural gas/biomethane and hydrogen blending and simultaneous transportation in currently operational gas networks.

From a Batch to a Continuous Supported Ionic Liquid Phase (SILP) Process: Anhydrous Synthesis of Oxymethylene Dimethyl Ethers

AbstractOxymethylene dimethyl ethers (OMEn; CH3(−OCH2)n−OCH3) are promising sustainable synthetic fuels when produced from CO2 and green H2. The synthesis pathway presented here overcomes synthetic problems and includes the reaction of dimethoxymethane (OME1) with molecular gaseous formaldehyde in a novel continuous, anhydrous reaction setup. An initially performed wide batch‐catalyst screening highlighted the salts M[NTf2]x with M=Cu+, Co2+ and Mg2+ as especially interesting catalysts (NTf2=N(SO2CF3)2). Supported ionic liquid phase (SILP)‐catalysts were prepared on this basis and demonstrated the successful synthesis of OMEn in a continuous process. The SILP‐catalysts immobilized in the IL EMIM[BF4] showed a fast and strong deactivation, but those with the IL EMIM[NTf2] showed excellent catalytic performance and stable results in continuous operations exceeding 19 h. The influence of the weight hourly space velocity (WHSV), the reaction temperature as well as the storage conditions of the catalysts (inert vs non‐inert) were investigated. 90 °C was identified as ideal reaction temperature. High feed‐gas flows (WHSV=15.8 h−1) are preferable in terms of product selectivity SOME2‐5>90 mol‐ % with an OME1 conversion XOME1=5.10 mol‐ % at the same time. We also demonstrated that the catalysts can be stored in air for 50 days without loss of activity. The SILP‐catalysts were analyzed by NMR and IR spectroscopy. Furthermore, the thermodynamics of the reaction mechanism of some selected catalysts was calculated by DFT theory to this reaction.

Integrating a Fischer Tropsch process into a pulp mill - A techno-economic assessment

To reduce the greenhouse gas emissions of the transport sector, synthetic fuels based on CO2 and H2 are one viable option. This paper evaluates the integration of a Fischer Tropsch process into a pulp mill to improve efficiency and to lower CO2 emissions. Different syngas preparation technologies, plant sizes, and gas loop designs are considered. The processes were simulated with a chemical process simulation software to retrieve mass and energy balances. Based on the simulations, the processes are evaluated regarding economics, CO2 emissions, and efficiency indicators.The Power-to-Fuel efficiency reaches almost 40 % for closed loop configuration with reverse water gas shift reactor for carbon monoxide production. For the open loop configuration the efficiency is tremendously lower. In closed loop configurations, the carbon efficiency reaches 80 %. The levelized cost of syncrude ranges from 3.28 to 7.69 €/kg. The most important impact on syncrude price comes from electricity price, investment cost, and efficiency of water electrolysis. Integrating the Fischer Tropsch process into the pulp mill shows advantages in terms of Power-to-Fuel efficiency and CO2 emissions but not necessarily in terms of economics.

A pluralist assessment of industrialization

The established method of health technology assessment (HTA) is in this study expanded to a Pluralist Technology Assessment (PTA) including the Ecosystem in the production function. Market economy can grow by moderate reciprocal relations where the Government supports the framework for free market enterprise. However, the PTA concludes that industrial side-effects such as global warming and job-related stress today more than outweigh contemporary gains by GDP growth. Sustainable development requires a stronger economic reciprocity with collaborative (public) finance of interventions for the common good in accordance with the democratic social contract claimed by Rousseau 1762. A development from moderate to strong reciprocity is definitely a biological option based on across-the-center collaboration between Social Liberal and Social Democrat parties. A critical economic-political reform for such sustainable development is a CO2 Tariff (ET) towards global warming. However, in a globalized economy there is a national conflict of interests between Eco-protection by ET and business/employment which slows down the implementation. So, a globalized economy requires that the ET is implemented from the international level. A major part of the international ET revenue, for instance by the partners of the Paris Agreement 2015, can be used for Direct Air Capture of CO2 (DAC) and spillover technologies for instance synthetic fuels for heavy transport by sea and aircrafts. At the national level, the ET revenue must be used partly for social compensation to low-income groups, partly for new technology development in special sectors as agriculture and transport by sea and air. At the population level, “Simple Living” as a bottom-up alternative to consumerism complements the political interventions. Part of Simple Living is meditative in-depth-relaxation for better stress-management where a professional collaboration between Medicine and Health Economics can accelerate the development.

Numerical and experimental investigations on the particle formation in oxymethylene ethers (OME[formula omitted], n = 2−4)/ethylene premixed flames

Alternative synthetic fuels can be produced by renewable energy sources and represent a potential route for solving long-term energy storage. Among them, oxygenated fuels have the advantage of significantly reducing pollutant emissions and can therefore be used as carbon-neutral substitute fuels for transportation. In this work, the sooting propensity of different oxymethylene ethers (OMEs) is investigated using a combined experimental and numerical study on a series of burner-stabilized premixed flames under mild to severe sooting conditions. Herein, mixtures of ethylene in combination with the three individual oxymethylene ether (OMEn) for n=2,3,4 are compared in terms of soot formation behavior with pure ethylene flames. The kinetic mechanism from Sun et al. (Proc. Combust. Inst. 36 (2017) 1269–1278) for OMEn combustion with n=1,2,3 is extended to include OME4 decomposition and combustion kinetics. It is combined with a detailed quadvariate soot model, which uses the Conditional Quadrature Method of Moments (CQMOM), and the soot simulation results are validated with Laser-Induced Fluorescence (LIF) and Laser-Induced Incandescence (LII) measurements. It is observed that the three investigated OMEn with n=2,3,4 show similar sooting behavior, mainly reducing larger aggregates while not significantly affecting the formation of smaller particles. Furthermore, the extent of soot reduction is comparable among the three OMEn. The trends and overall reduction are captured very well by the model. The modeling results are analyzed through reaction pathway analyses and sensitivity studies that show the importance of OMEn decomposition and the formation of formaldehyde (CH2O) under rich conditions for reducing species relevant for soot precursor formation. These findings are based on the negligible differences in soot formation between the different OMEn fuels observed in this study.

Defect-Driven Efficient Selective CO2 Hydrogenation with Mo-Based Clusters.

Synthetic fuels produced from CO2 show promise in combating climate change. The reverse water gas shift (RWGS) reaction is the key to opening the CO2 molecule, and CO serves as a versatile intermediate for creating various hydrocarbons. Mo-based catalysts are of great interest for RWGS reactions featured for their stability and strong metal-oxygen interactions. Our study identified Mo defects as the intrinsic origin of the high activity of cluster Mo2C for CO2-selective hydrogenation. Specifically, we found that defected Mo2C clusters supported on nitrogen-doped graphene exhibited exceptional catalytic performance, attaining a reaction rate of 6.3 gCO/gcat/h at 400 °C with over 99% CO selectivity and good stability. Such a catalyst outperformed other Mo-based catalysts and noble metal-based catalysts in terms of facile dissociation of CO2, highly selective hydrogenation, and nonbarrier liberation of CO. Our study revealed that as a potential descriptor, the atomic magnetism linearly correlates to the liberation capacity of CO, and Mo defects facilitated product desorption by reducing the magnetization of the adsorption site. On the other hand, the defects were effective in neutralizing the negative charges of surface hydrogen, which is crucial for selective hydrogenation. Finally, we have successfully demonstrated that the combination of a carbon support and the carbonization process synergistically serves as a feasible strategy for creating rich Mo defects, and biochar can be a low-cost alternative option for large-scale applications.

Analysis of integrated CO2 capture and utilization via calcium-looping in-situ dry reforming of methane and Fischer-Tropsch for synthetic fuels production

Calcium-looping is an attractive approach for removing CO2 in flue gas from the coal-fired power plant to form CaCO3. The integration of CO2 capture via calcium-looping and in-situ dry reforming of methane with CaCO3 allows the simultaneous CaCO3 decomposition to regenerate CaO and syngas production. The produced syngas is expected for further utilization, e.g. Fischer-Tropsch synthesis to produce valuable fuels. In this work, an integrated process of calcium-looping in-situ dry reforming of methane and Fischer-Tropsch was developed using Aspen Plus. Moreover, two other processes were also simulated as the comparison, consisting of the serial process of calcium-looping CO2 capture, ex-situ dry reforming of methane with CO2 and Fischer-Tropsch and the standalone process of calcium-looping CO2 capture. The results indicate that the reduction in the demand for CaO sorbent and the enhancement in Fischer-Tropsch products yield and carbon conversion efficiency are achieved by integrating in-situ dry reforming of methane with CaCO3. Additionally, integrating CO2 capture and in-situ dry reforming of methane with CaCO3 in the case of the integrated process is efficient for enhancing the system efficiency and energy availability. Compared with the serial process, the integrated process shows a drop in the heat energy requirement of 28.08% and possesses the energy conversion efficiency of 43.74% and exergy efficiency of 41.81%. This work exhibits the prospect of the integrated process of calcium-looping in-situ dry reforming of methane and Fischer-Tropsch in the field of CO2 capture and utilization for Fischer-Tropsch fuels production.

Land use of energy supply for carbon neutral mobility: a well-to-wheel analysis

BackgroundThe transition to carbon neutral mobility will require a lot of carbon neutral energy, but a lot of spaceas well. In many countries, it will be a challenge to find this space or to import enough energy. Land use indicators related to sustainable mobility usually focus on space for transport infrastructure and parking, i.e. direct land use, and do not include energy supply. Existing literature on the emerging research field of ‘energy landscapes’ has not covered the transport sector.ObjectiveThe aim of this paper is to estimate the order of magnitude of land or sea area required for carbon neutral mobility.MethodIn a well-to-wheel analysis, we investigate the land use for the production, transport, storage, distribution, and charging/refuelling of carbon neutral energy carriers for various modes of transport. The analysis focuses on the Netherlands, but part of the results are expected to be broadly applicable to other countries as well.FindingsThe results show that electricity from wind or solar energy supplied to electric vehicles is the most space efficient. Use of hydrogen and synthetic fuels in vehicles takes 2–5 times more land, while use of biofuels from energy crops takes 100 times more land compared to the electricity route. We also conclude that the indirect land use for energy supply for carbon neutral road transport in the Netherlands is in the same order of magnitude as the current direct land use of road mobility.