Application of advanced correlative approaches to modeling hydrogen solubility in hydrocarbon fuels

In petroleum and petrochemical refineries, having precise knowledge regarding H₂ solubility in hydrocarbon fuels and feedstocks is critical. In this study, the hydrogen solubility in hydrocarbon fuels was estimated using genetic programming (GP) and group method of data handling (GMDH), two exemplary robust advanced models for generating correlation. To do this, 445 observations derived from labratory findings on hydrogen solubility in 17 different hydrocarbon fuels such as bitumen, atmospheric residue, heavy coking gas oil, heavy virgin gas oil, light virgin gas oil, straight run gas oil, shale fuel oil, dephenolated shale fuel oil, diesel, hydrogenated coal liquid, coal liquid, and coal oil, over a large interval of P- operating pressures and T-temperatures were collected. Temperature, pressure, as well as density at 20 °C, molecular weight, and weight percentage of carbon (C) and hydrogen (H) in hydrocarbon fuels, were used as input parameters in developing robust correlations. The outcomes showed the GMDH approach is more precise compared to the GP, with a root mean square error (RMSE) of 0.053302 and a determination coefficient (R²) of 0.9641. Additionally, sensitivity analysis showed that pressure, followed by temperature and H (wt%) of hydrocarbon fuels, has the greatest impact on hydrogen solubility in hydrocarbon fuels. Ultimately, the Leverage method's results suggested that the GMDH model could be relied on to predict hydrogen solubility in hydrocarbon fuels.     

An overview of solar decarbonization processes,reacting oxide materials,and thermochemical reactors for hydrogen and syngas production

Solar decarbonization processes are related to the different thermochemical conversion pathways of hydrocarbon feedstocks for solar fuels production using concentrated solar energy as the external source of high-temperature process heat. The main investigated routes aim to convert gaseous and solid feedstocks (methane, coal, biomass …) into hydrogen and syngas via solar cracking/pyrolysis, reforming/gasification, and two-step chemical looping processes using metal oxides as oxygen carriers, further associated with thermochemical H₂O/CO₂ splitting cycles. They can also be combined with metallurgical processes for production of energy-intensive metals via solar carbothermal reduction of metal oxides. Syngas can be further converted to liquid fuels while the produced metals can be used as energy storage media or commodities. Overall, such solar-driven processes allow for improvements of conversion yields, elimination of fossil fuel or partial feedstock combustion as heat source and associated CO₂ emissions, and storage of intermittent solar energy in storable and dispatchable chemical fuels, thereby outperforming the conventional processes. The different solar thermochemical pathways for hydrogen and syngas production from gaseous and solid carbonaceous feedstocks are presented, along with their possible combination with chemical looping or metallurgical processes. The considered routes encompass the cracking/pyrolysis (producing solid carbon and hydrogen) and the reforming/gasification (producing syngas). They are further extended to chemical looping processes involving redox materials as well as metallurgical processes when metal production is targeted. This review provides a broad overview of the solar decarbonization pathways based on solid or gaseous hydrocarbons for their conversion into clean hydrogen, syngas or metals. The involved metal oxides and oxygen carrier materials as well as the solar reactors developed to operate each decarbonization route are further described.     

Data-driven modeling of H2 solubility in hydrocarbons using white-box approaches

As a result of technological advancements, reliable calculation of hydrogen (H₂) solubility in diverse hydrocarbons is now required for the design and efficient operation of processes in chemical and petroleum processing facilities. The accuracy of equations of state (EOSs) in estimating H₂ solubility is restricted, particularly in high-pressure or/and high-temperature conditions, which could result in energy loss and/or potential safety and environmental problem. Two strong machine learning techniques for building advanced correlation were used to evaluate H₂ solubility in hydrocarbons in this study which were Group method of data handling (GMDH) and genetic programming (GP). For that purpose, 1332 datasets from experimental results of H₂ solubility in 32 distinct hydrocarbons were collected from 68 various systems throughout a wide range of operating temperatures from 98 K to 701 K and pressures from 0.101325 MPa to 78.45 MPa. Hydrocarbons from two distinct classes include alkane, alkene, cycloalkane, aromatic, polycyclic aromatic, and terpene. Hydrocarbons have a molecular mass range of 28.054–647.2 g/mol, which corresponds to a carbon number of 2–46. Solvent molecular weight, critical pressure, and critical temperature, as well as pressure and temperature operational parameters, were used to create the features. With a regression coefficient (R²) which was equal to 0.986 and root mean square error (RMSE) which was 0.0132, the GP modeling approach estimated experimental solubility data more accurately than the GMDH approach. Operating pressure, followed by molecular weight of hydrocarbon solvents and temperature, had the greatest influence on estimation H₂ solubility, according to sensitivity analysis. The GP model shown in this paper is a reliable development that may be used in the chemical and petroleum sectors as a reliable and effective estimator for H₂ solubility in diverse hydrocarbons.     

Hybrid boosting algorithms and artificial neural network for wind speed prediction

Energy sources are an important foundation for national economic growth. The future of energy sources depend on the energy controls. The reserves of fossil energy have declined significantly, and environmental pollution has increased dramatically due to excessive fossil fuel consumption. At this point, wind energy can be used as one of the key source of renewable energy. It has a remarkable importance among the low-carbon energy technologies. The primary aim of wind energy production is to reduce dependence on fossil fuels that affect environment adversely. Therefore, wind energy is analyzed to develop new energy resources. The main issue related to evaluation of the wind energy potential is wind speed prediction. Due to the high volatile and irregular nature of wind speed, wind speed prediction is difficult. To cope with complex data structure, this study presents the development of extreme gradient boosting (XGBoost), adaptive boosting (AdaBoost), and artificial neural network (ANN) within particle swarm optimization (PSO) parameter optimization for hourly wind speed prediction. To compare the proposed hybrid methods, various performance measures, the Pearson's test, and the Taylor diagram are used. The results showed that proposed hybrid methods provide reasonable prediction results for wind speed prediction.     

Autothermal reforming of aliphatic and aromatic hydrocarbon liquids

The process of catalytic partial oxidation of hydrocarbon liquids in the presence of steam to generate a hydrogen-rich gas is called autothermal reforming (ATR), wherein no external heat source other than reactants preheat is required. As an alternative to conventional steam reforming, the ATR process, considered for use with fuel cell power plants, may expand the range of fuels that can be converted to hydrogen to include middle distillate fuels derived from petroleum or coal.Carbon formation constitutes the main problem in autothermal reforming of heavy fuels under conditions of high thermal and conversion efficiency. A better understanding of the parametric effects on carbon formation in ATR can be obtained by studying the basic types of components that occur in heavy fuels (paraffins, aromatics, olefins and sulfur compounds). Experimental results are presented here for the ATR of paraffins (n-hexane, n-tetradecane) and aromatics (benzene, naphthalene) over supported nickel catalysts. Under similar operating conditions, reaction temperatures and intermediates, and the propensity for carbon formation in the autothermal reformer have been found to be characteristic of the hydrocarbon type used. The effects of various operating parameters on carbon formation are illustrated for the different fuels used in ATR. In tests with aliphatic/aromatic mixtures, synergistic effects have been determined.     

Greenhouse gas implications of using coal for transportation: Life cycle assessment of coal-to-liquids,plug-in hybrids,and hydrogen pathways

Using coal to produce transportation fuels could improve the energy security of the United States by replacing some of the demand for imported petroleum. Because of concerns regarding climate change and the high greenhouse gas (GHG) emissions associated with conventional coal use, policies to encourage pathways that utilize coal for transportation should seek to reduce GHGs compared to petroleum fuels. This paper compares the GHG emissions of coal-to-liquid (CTL) fuels to the emissions of plug-in hybrid electric vehicles (PHEV) powered with coal-based electricity, and to the emissions of a fuel cell vehicle (FCV) that uses coal-based hydrogen. A life cycle approach is used to account for fuel cycle and use-phase emissions, as well as vehicle cycle and battery manufacturing emissions. This analysis allows policymakers to better identify benefits or disadvantages of an energy future that includes coal as a transportation fuel. We find that PHEVs could reduce vehicle life cycle GHG emissions by up to about one-half when coal with carbon capture and sequestration is used to generate the electricity used by the vehicles. On the other hand, CTL fuels and coal-based hydrogen would likely lead to significantly increased emissions compared to PHEVs and conventional vehicles using petroleum-based fuels.     

Sustainability and challenges in hydrogen production: An advanced bibliometric analysis

Hydrogen has a high and diversified amount of feedstocks, methods, and improvement processes for its production. In recent years, studies on hydrogen production have been growing and diversifying to a greater extent. Hydrogen production can be based on renewable feedstocks such as biomass or fossil fuels such as petroleum. An analysis of 10,655 publications from the Web of Science Core Collection database (2010–2022) was performed using VOSviewer, CiteSpace and Microsoft excel. The top three organizations that had the highest number of publications in the field of hydrogen production included the Chinese Academy Of Sciences, Ontario Tech University and Xi An Jiaotong University. The journal with the largest number of publications is the International Journal Of Hydrogen Energy. In addition to organizations and journals, the most promising authors and literature in this field of research were analyzed. Through cluster analysis, it was found that two constant search fields were Photocatalytic hydrogen production and Fermentative hydrogen production. Future studies should focus on process design, continuous photo-hydrogen production and looping steam. This bibliometric study focused on illustrating the overview of hydrogen production research, conducting a systematic survey of current research, which could be used by industry professionals and researchers interested in this area.     

Hydrogen energy systems technology study

The National Aeronautics and Space Administration (NASA) Office of Energy Programs initiated the Hydrogen Energy Systems Technology (HEST) Study in the autumn of 1974. The Caltech Jet Propulsion Laboratory (JPL) was made responsible for conducting the study and reporting the results, with active support from several NASA Centres through a Working Panel. Objectives of the study were defined to be the assessment of national needs for hydrogen, based on current uses and visible trends, and determination of the critical research and technology activities required to meet these needs, with attention to economic, social, and environmental considerations, providing a basis for the planning of a hydrogen research and technology program.The HEST Study found current U.S. hydrogen utilization to be dominated by chemical-industry and petroleum-processing applications, and to represent 3% of total energy consumption. The study's projections of hydrogen uses show growth the remainder of this century by at least a factor of five, and perhaps a factor of twenty. New applications in the manufacture of synthetic fuels from coal and directly as an energy storage medium and fuel are expected to emerge later this century. Of these new uses, electric utility energy storage for peak-shaving, supplements to the natural gas supply and special purpose transportation fuel such as aircraft, show promise.The Study concludes that the development and implementation of new means of supplying hydrogen, replacing the use of natural gas and petroleum feedstocks, are imperative. New production technology is essential to support even the lowest growth estimate. Methods based on alternative fossil feedstocks, such as coal and heavy oils, which are less expensive and nearer to technical maturity than non-fossil production systems, should be made operational while these feedstocks are abundant. Concurrently, the long-term tasks of advancing electrolysis technology, researching other water-splitting techniques, and integrating these with developing nuclear and emerging solar primary-energy systems, must be carried on, together with work on hydrogen combustion systems and research in materials and safety engineering. Systems studies and assessments of the economic, social and environmental impacts of hydrogen technology are also called for.     

浅析石油替代燃料的开发

论述了开发非常规石油资源是解决本世纪石油资源量下降的最主要、最实际的途径之一;研究开发石油替代燃料是解决本世纪世界石油资源量下降的一个重要战略措施,也是我国能源安全战略的一个重要组成部分。石油替代燃料包括天然气和气态烃以及一些二次能源,如生物质能（乙醇、生物柴油）和煤基燃料（煤制油）、氢能等。分别阐述了各种石油替代燃料的国内外开发现状、存在问题和开发前景。     

Hydrogen use: synfuels

The role of hydrogen in the processing of alternate energy sources to produce synthetic fuels is reviewed. The differences among oil shale, coal, tar sands and petroleum are discussed and related to the utilization of hydrogen in the processing technology.     

The potential of liquid hydrogen as a military aircraft fuel

As domestic petroleum supplies diminish and prices escalate, the U.S. Air Force will need to consider the implications of relying on primary energy resources other than petroleum for its aviation fuel needs. Our recent studies have examined various candidate synthetic fuels and the types of vehicles in which they might be employed. In this paper, we have emphasized those results which highlight the possible use of liquid hydrogen as a fuel for very large airplanes (with maximum gross weights in excess of one million pounds).

Comparisons are provided of the life-cycle costs and life-cycle energy consumption for both synthetic jet-fuel and liquid hydrogen fueled airplanes. Both fuels are assumed to be synthesized from coal. In addition, the relative cost-effectiveness and energy-effectiveness of the two alternatives are presented for a variety of mission applications.

These results suggest that a synthetic jet-fuel (similar to today's Jet-A or JP-4) derived from coal is more attractive than liquid hydrogen as a military aircraft fuel.     

Industrial scale production of hydrogen from natural gas,naphtha and coal

This paper reviews the three major routes for the production of hydrogen from fossil fuels.Today there is considerable interest in the production of hydrogen via the gasification of coal. Existing processes and developments are listed.The partial oxidation processes which utilize feedstocks ranging from light hydrocarbons to heavy fuel oil are attractive due to feedstock flexibility.Hydrogen production based on the steam reforming of light hydrocarbons has become the most widely used process as a result of, in general, better economics.     

基于物理成因的中长期径流预测模型研究

可靠的中长期径流预测对水资源开发等具有重要意义。为此,筛选了影响径流的主要物理因子,引入极端梯度提升(XGBoost)算法构建中长期径流预测模型,通过纳什效率系数评价模型精度,并与多元线性回归模型(LR)、梯度提升决策树模型(GBDT)进行比较。实例应用结果表明,该模型对月径流过程的预测精度较高,训练期和验证期的纳什效率系数均值分别达到了0.9和0.7,且泛化能力优于GBDT模型和LR模型,用于中长期径流预测具有一定的可靠性和稳定性。     

生物质到生物燃料—费托合成催化剂的研究进展

费托合成反应是煤、甲烷和生物质等非油基碳资源转化制高品质液体燃料或化学品的重要途径。以生物质基合成气为原料,利用传统的Fe、Co催化剂制备生物燃料引起普遍关注。本文简要总结了近年来高性能Fe基和Co基费托合成催化剂的发展,以及近年来新型材料和核壳结构的双功能催化剂在费托合成中的应用。重点关注了生物质合成气方面的应用,比较了Fe、Co催化剂在该应用中的特点。虽然Co基催化剂较Fe基催化剂有更好的活性,但在BTL（Biomass-To-Liquid）过程中需要考虑多种因素,Fe基催化剂可能更具优势,开发廉价高性能的Fe基催化剂可能成为BTL-FT催化剂的发展方向。     

Oil and natural gas prices and greenhouse gas emission mitigation

The hikes in hydrocarbon prices during the last years have lead to concern about investment choices in the energy system and uncertainty about the costs for mitigation of greenhouse gas emissions. On the one hand, high prices of oil and natural gas increase the use of coal; on the other hand, the cost difference between fossil-based energy and non-carbon energy options decreases. We use the global energy model TIMER to explore the energy system impacts of exogenously forced low, medium and high hydrocarbon price scenarios, with and without climate policy. We find that without climate policy high hydrocarbon prices drive electricity production from natural gas to coal. In the transport sector, high hydrocarbon prices lead to the introduction of alternative fuels, especially biofuels and coal-based hydrogen. This leads to increased emissions of CO₂. With climate policy, high hydrocarbon prices cause a shift in electricity production from a dominant position of natural gas with carbon capture and sequestration (CCS) to coal-with-CCS, nuclear and wind. In the transport sector, the introduction of hydrogen opens up the possibility of CCS, leading to a higher mitigation potential at the same costs. In a more dynamic simulation of carbon price and oil price interaction the effects might be dampened somewhat.     

Economics and potential application of electrolytic hydrogen in the next decades

The demand for hydrogen will increase within the next decades mainly due to the necessity of producing clean and environmentally accepted fuels from fossil hydrocarbon resources of minor quality and from coal.The use of electrolytic hydrogen is limited by the economics of its production which is dominated by the cost of the electrical energy necessary for water splitting. The potential for cost reductions by the application of new electrolysis technologies is investigated and break-even electricity prices are calculated at which electrolytic hydrogen can compete with hydrogen produced from fossil fuels.Although in general electrolytic hydrogen production is not yet competitive, there are good prospects for advanced, highly efficient processes (e.g. the electrolysis of steam) to be developed within the next decades. Small and medium hydrogen production plants of this type might be competitive soon, and they are attractive if the oxygen by-product and the environmental advantages are taken into account.     

An experimental investigation on hydrogen as a dual fuel for diesel engine system with exhaust gas recirculation technique

With higher rate of depletion of the non-renewable fuels, the quest for an appropriate alternative fuel has gathered great momentum. Though diesel engines are the most trusted power sources in the transportation industry, due to stringent emission norms and rapid depletion of petroleum resources there has been a continuous effort to use alternative fuels. Hydrogen is one of the best alternatives for conventional fuels. Hydrogen has its own benefits and limitations in its use as a conventional fuel in automotive engine system.In the present investigation, hydrogen-enriched air is used as intake charge in a diesel engine adopting exhaust gas recirculation (EGR) technique with hydrogen flow rate at 20 l/min. Experiments are conducted in a single-cylinder, four-stroke, water-cooled, direct-injection diesel engine coupled to an electrical generator. Performance parameters such as specific energy consumption, brake thermal efficiency are determined and emissions such as oxides of nitrogen, hydrocarbon, carbon monoxide, particulate matter, smoke and exhaust gas temperature are measured. Usage of hydrogen in dual fuel mode with EGR technique results in lowered smoke level, particulate and NO_x emissions.     

Some thoughts about the hydrogen civilization and the culture development

Civilization is defined as an aggregate achievement of inventions for realizing lofty human ideas, and culture is defined as the intellectual side. The realization of human ideas is the sustainable development (SD), and one of these pillars is the energy system. The main current of the human energy carriers has made the transition from coal to petroleum, and from petroleum to natural gas. This trend means the transition from the fuels with a larger ratio of carbon to those with a larger ratio of hydrogen. Ultimately, the main energy current will be converged to hydrogen. The hydrogen civilization is about to emerge today. The centripetal force acting upon every fuel toward hydrogen has an intellectual analogy to Brownian motion, which is one of the main topics of the concerned complexity science. Moreover, Ashby's requisite variety law indicates that the civilization must wear the cloth of the culture in order to build up the endlessly sustainable civilization.     

Reaction of oxygenated biomass pyrolysis model compounds over a ZSM-5 catalyst

The application of zeolite catalysis to the upgrading of biomass-derived pyrolysis vapours has received increasing interest in recent years. It represents a potential route for the production of hydrocarbon products which can be used as substitutes for traditional fossil fuels. The complex nature of the pyrolysis oils means that there is only a very limited understanding of the reactions which take place during zeolite catalysis. Therefore, the upgrading of individual oxygenated compounds which are present in the pyrolysis oils can help in developing an understanding of the overall catalysis process. In this work, four oxygenated compounds: methanol, furfural, anisole and cyclopentanone were passed over the zeolite catalyst ZSM-5 in its hydrogen form at different temperatures varying from 300 to 500°C. The results show that methanol can be catalytically converted to hydrocarbon products at relatively low catalysis temperatures of 300–350°C, whereas the other oxygenated feedstocks require higher catalysis temperatures. The formation of polycyclic aromatic hydrocarbons (PAHs) was found to vary depending on the oxygenated feedstock. The presence of PAHs is undesirable due to their toxic nature.