Tandem hydroalkylation and deoxygenation of lignin-derived phenolics to synthesize high-density fuels

Lignin is the most abundant naturally phenolic biomass,and the synthesis of high-performance renewable fuel from lignin has attracted significant attention.We propose the efficient synthesis of high-density fuels using simulated lignin cracked oil in tandem with hydroalkylation and deoxygenation reactions.First,we investigated the reaction pathway for the hydroalkylation of phenol,which competes with the hydrodeoxygenation form cyclohexane.And then,we investigated the effects of metal catalyst types,the loading amount of metallic,acid dosage,and reactant ratio on the reaction results.The phenol hydroalkylation and hydrodeoxygenation were balanced when 180℃ and 5 MPa H_(2)with the alkanes yield of 95%.By extending the substrate to other lignin-derived phenolics and simulated lignin cracked oil,we obtained the polycyclic alkane fuel with high density of 0.918 g·ml^(-1)and calorific value of41.2 MJ·L^(-1).Besides,the fuel has good low-temperature properties(viscosity of 9.3 mm^(2)·s^(-1)at 20℃ and freezing point below-55℃),which is expected to be used as jet fuel.This work provides a promising way for the easy and green production of high-density fuel directly from real lignin oil.

Conversion of lignin oil and hemicellulose derivative into high-density jet fuel

Synthesizing high-density fuel from lignocellulose can not only achieve green and low-carbon development,but also expand the feedstock source of hydrocarbon fuel.Here,we reported a route of producing high-density fuel from lignin oil and hemicellulose derivative cyclopentanol through alkylation and hydrodeoxygenation,HY with SiO_(2)/Al_(2)O_(3) molar ratio of 5.3 was screened as the alkylation catalyst in the reaction of model phenolic compounds and mixtures,and the reaction conditions were optimized to achieve conversion of phenolic compounds higher than 87%and selectivity of bicyclic and tricyclic products higher than 99%.Then two phenolic pools simulating the composition of two typic lignin oils were studied to validate the alkylation and analyze the competition mechanism of phenolic compounds in mixture system.Finally,real lignin oil from depolymerized of beech powder was tested,and notably80%of phenolic monomers in the oil were converted into fuel precursor.After hydrodeoxygenation,the alkylated product was converted to fuel blend with a density of 0.91 g/mL at 20℃and a freezing point lower than-60℃,very promising as high density fuel.This work provides a facile and energyefficient way of synthesizing high-performance jet fuel directly from lignocellulosic derivatives,which decreases processing energy consumption and improve the utilization rate of feedstock.

Rapidly determining fuel pollution level of aviation lubricating oil 50-1-4Φby mid-infrared spectrometry

A series of aviation lubrication oil 50-1-4φ samples were prepared with different RP-3 content, and then these sam- ples were analyzed by Fourier transform mid-infrared spectrometer （FTIR）. The infrared region of 805--755 cm-1 was selected as quantitative area for determining fuel pollution level of aviation lubrication oil. Finally, correlation of the testing peak area and the fuel pollution level of corresponding samples were analyzed, and the regression equation was proposed. The results show that determining jet fuel pollution level of aviation lubricating oil by FTIR is feasible and reliable.

Effect of Nozzle Inclination Angle on Fuel-Air Mixing and Combustion in a Heavy Fuel Engine

Heavy-fuel engines are widely used in UAVs(Unmanned Autonomous Vehicles)because of their reliability and high-power density.In this study,a combustion model for an in-cylinder direct injection engine has been imple-mented using the AVL FIRE software.The effects of the angle of nozzle inclination on fuel evaporation,mixture distribution,and combustion in the engine cylinder have been systematically studied at 5500 r/min and consider-ing full load cruise conditions.According to the results,as the angle of nozzle inclination increases,the maximum combustion explosion pressure in the cylinderfirst increases and then it decreases.When the angle of nozzle incli-nation is less than 45°,the quality of the mixture in the cylinder and the combustion performance can be improved by increasing the angle.When the angle of nozzle inclination is greater than 45°,however,the mixture unevenness increases slightly with the angle,leading to a deterioration of the combustion performances.When the angle of nozzle inclination is between 35°and 55°,the overall combustion performance of the engine is rela-tively good.When the angle of nozzle inclination is 45°,the combustion chamber’s geometry and the cylinder’s airflow are well matched with the fuel spray,and the mixture quality is the best.Compared with 25°,the peak heat release rate increases by 20%,and the maximum combustion burst pressure increases by 5.5%.

Recent Progress in Heavy Fuel Aviation Piston Engine

Heavy fuel aviation piston engines(HF-APEs)refer to the engine using fuels with high flash point,such as kerosene or light diesel.Here technique specifications of some classical foreign HF-APEs(Hirth3503,Zanzottera 498)are introduced.Recent progress and trend of fuel injection,fuel ignition,working cycle,intake charging,thermal management and electronic control of HF-APE are compared and summarized.Emphases are put on the technological difficulties,solutions and development tendency in the design,retrofitting and manufacturing of HF-APE aiming to provide references for the research of related area and the development of prototype HF-APE in China.

Sustainable synthesis of high-density fuel via catalytic cascade cycloaddition reaction

The access to high-density hydrocarbon fuels from biomass for the reduction of dependence on fossil resources has been a research highlight in recent years. It is well known that cycloalkanes are the components of fuels with higher energy density than straight or branched alkanes. Herein, we developed a new catalytic pattern to synthesize dimethyltetradecahydroanthracenes(DMTHA), a kind of tricyclic alkane, from biomass-derived isoprene and p-benzoquinone via a cascade Diels-Alder reaction followed by a hydrodeoxygenation reaction. Vanadium supported on titanium dioxide(V-TiO_(2)) was applied to catalyze the cascade Diels-Alder reaction and it was disclosed that V with appropriate V^(4+)/V^(5+) ratio on the surface of TiO_(2) could activate quinones. Experimental tests showed that the heating value of final products was up to 45.7 MJ/kg. The development of new high-density fuel molecules is a long-term trend for the future renewable and sustainable fuel energy application.

Past, Present and Future: A Role for Liquid Biofuels in Transitioning to Net Zero?

Over the last decade, the uptake rate of first-generation biofuels (ethanol and biodiesel) has decelerated as low blend limits have increased only slowly and extreme volatility in oil prices has limited investment in biofuels production infrastructure. Concerns over the environmental impacts of large-scale biofuels production combined with tariff barriers have greatly restricted the global trade in biofuels. First-generation biofuels produced either by fermentation of sugars from maize or sugarcane (ethanol) or transesterification of triglycerides (biodiesel) presently contribute less than 4% of terrestrial transportation fuel demand and techno-economic modelling foresees this only slowly increasing by 2035. With internal combustion and diesel engines widely anticipated as being phased out in favour of electric power for motor vehicles, a much-reduced market demand for biofuels is likely if global demand for all liquid fuels declines by 2050. However, second-generation, thermochemically produced and biomass-derived fuels (renewable diesel, marine oils and sustainable aviation fuel) have much higher blend limits;combined with policies to decarbonise the aviation and marine industries, major new markets for these products in terrestrial, marine and aviation sectors may emerge in the second half of the 21st century.

Aviation Fuel System Safety Management Analysis

The development of China’s aviation industry is accelerating,especially in terms of national political protection,military security and economic security.In the aviation industry’s aviation fuel system management,safety management is an important content.This paper focuses on the safety management of aviation fuel systems.

Municipal Waste Plastics Conversion into Aviation Fuel

Aviation fuel is in great demand globally. The increased demand and high price for energy sources are driving efforts to convert natural non-renewable organic compounds into useful hydrocarbon fuel materials such as in form of aviation fuel. Alternate sources to these non-renewable hydrocarbon fuels are important and necessary. Much of these alternative sources are focused on biomass however, there are strong benefits of deriving fuels from waste plastic materials. Thermal processes can be used to convert waste plastics into hydrocarbon fuels like aviation fuel, which have unlimited applications in airline industries, as well as in transportation and power generation industries. These thermal processes are used to break down the long carbon chains found in plastics into the shorter chains in a temperature range from 300-450 ℃. This method has been carried out in succession in previous experiments. This simple and economically viable process has been developed to convert the hydrocarbon polymers of waste plastics into the short and medium chain hydrocarbons of liquid fuels. Based on the initial characterization, a fractionated portion of the developed fuel shows properties similar to some of the commercially available aviation fuels.

Engine Performance and Emission Characteristics of Cellulosic Jet Biofuel Blends

Aviation biofuels have the potential to reduce greenhouse gas emissions and improve engine performance. Theaim of this study was to assess the suitability of various jet biofuel blends for use in a ZF850 jet engine. The effects of theblends on engine performance were assessed under various thrust output settings with respect to the thrust, thrust-specificfuel consumption, emission characteristics, exhaust gas temperature, acceleration and deceleration performance. Blendingwith catalytic hydrothermolysis jet (CHJ) fuel improved the combustion efficiency by reducing carbon monoxide andunburned hydrocarbon emissions and markedly reducing PM2.5 emissions. However, a slight reduction in thrust output wasobserved. Throughout the entire range of thrust output settings, the 10% CHJ fuel blend provided higher thrust, lower thrustspecificfuel consumption, and lower exhaust gas temperature. The CHJ fuel blends exhibited no significant effects on thedeceleration performance, while the 5% and 15% blends caused a 0.4 s delay in the time required for complete acceleration.Global sensitivity analysis was conducted to better understand the effects of the fuel blends on engine performance andemission characteristics. This analysis identified the critical parameters of engine performance as engine-influence and fuelinfluenceparameters and engine-influence and fuel-less influence parameters. The overall engine efficiency benefit was nonlinearlyrelated to the blend ratio and thrust output. The results indicate that the use of CHJ fuel blends can improve engineefficiency if they comply with the engine design and control regulations.

Chemical Properties,Low-Temperature Performance,and Burning Performance of Bio-Jet Fuel

The effects of composition of bio-jet fuels on freezing point,smoke point,distillation range,and flash point are investigated.Performance tests using petroleum-based jet fuel with different compositions are conducted in line with standard test specifications.The results show that alkylbenzenes reduce the freezing point,with the amount of reduction becoming greater with increasing alkylbenzene content.For a 25%content of the C_8 aromatic xylene,the freezing point is in the range from-55.5℃to-60.1℃.The presence of monocyclic aromatic hydrocarbons leads to an increase in carbon deposition performance,especially when alkyl side chains are present.With cycloalkanes,carbon deposition is reduced,although alkyl side chains weaken this beneficial effect.Isomeric hydrocarbons are beneficial in reducing carbon deposition.The ASTM D7566 specifications for the distillation range are based on the average properties of petroleum-based aviation fuel,and if all the parameters governing the distillation range of an alternative jet fuel are at their lower limits,it is necessary to check whether other performance standards are met.Light components affect the flash point greatly,with 5%of benzene reducing the flash point by 17℃,whereas intermediate components(e.g.,xylene and ethylbenzene)and heavier components have less impact.Although alcohols provide better combustion performance,their content must be strictly limited owing to their effects in reducing the flash point.

美国可持续航空燃料发展对我国的启示

应用可持续航空燃料(SAF)被航空业界认为是最具潜力的碳减排措施,到2050年航空业65%的碳减排将通过使用SAF来实现。美国希望凭借领先的工艺技术、充足且丰富的原材料以及补贴政策的有效激励,成为新兴SAF市场的全球领导者。未来具有较大发展前景的SAF技术路线包括酯类和脂肪酸类加氢工艺(HEFA)、费托合成工艺(FT合成)、醇喷合成工艺(ATJ)、动力合成液体燃料工艺(PtL)。美国目前主要采用的是HEFA路线,但由于面临原料短缺问题,未来将逐渐被ATJ、FT合成等路线取代。美国每年约有10×10^(8)t的生物质能够可持续地生长或收集,其中将藻类转化为可再生燃料受到了美国极大的重视。美国针对SAF政策的特点是以鼓励性、支持性为主,主要运用财政补贴、税收减免等政策手段。中国是继美国之后的第二大航空市场,对SAF有着巨大的市场需求。我国可以借鉴美国的经验,尽早建立SAF产业联盟,重视SAF原料的创新,加大SAF炼制工艺认证和认证标准的建设力度,构建积极的产业政策和财税政策,而最重要的是加强重点技术方向的研发投入和支持力度,从而降低生产成本。

基于演化博弈分析的可持续航空燃油与碳市场协同减排研究

面对全球气候变化的严峻挑战,航空业作为温室气体排放的重要领域,其减排行动对于实现全球气候目标至关重要。可持续航空燃油(SAF)作为一种具有显著减排潜力的替代能源,其推广与应用成为航空业减排的关键。然而,SAF的广泛应用需要政府和航空公司的共同努力与协作。本文旨在通过博弈论的视角,构建政府与航空公司的双方演化博弈模型,分析SAF与碳市场协同减排机理。研究结果表明,合理的碳市场机制能够使航空公司通过加注SAF在实现减排的同时在碳市场中获益,进而激励SAF的规模化应用;降低SAF的采购价格以及对航空公司加注SAF提供政策激励措施,同样可以促进SAF的应用,实现减排目标。基于此,本文建议政府在初期通过设置较低的减排目标和提供研发支持,促进SAF技术的成熟和市场接受度。随着市场的发展,逐步提高碳配额要求和碳价,以激励航空公司增加SAF的使用比例,实现长期减排目标。本文的研究在推动SAF和碳市场协同减排中的决策中,为政府部门和航空公司提供了理论依据和实践指导,有助于促进航空业的绿色转型和可持续发展。

氢能源飞机的现状与未来

航空运输业碳排放较高,因此计划用氢能源代替传统航空燃油以降低碳排放,以氢燃料电池和氢燃料航空发动机作为飞机的动力源。围绕氢能源本身,对氢燃料电池和氢燃料航空燃气涡轮发动机展开论述,总结氢能源发展的主要技术难题,为氢能源飞机发展提供参考。

环境背压和喷射压力对航空重油空气辅助喷射喷雾特性影响

单一重油燃料的战场作战要求使航空重油活塞发动机的研发提升到一个新的高度。本文基于点燃式四冲程航空重油活塞发动机的空气辅助喷射技术,重点研究了环境背压和喷射压力对喷雾宏观形态发展和喷雾微观粒径分布的影响。结果表明,喷雾横向贯穿距和纵向贯穿距与环境背压成反比,且呈两个阶段的发展趋势,第一阶段横向和纵向贯穿距呈线性增加;第二阶段的贯穿距增加速度放缓。喷雾纵向贯穿距随喷射压力升高而增加,不同喷射压力的喷雾锥角均是先急速增加到一定值后开始回落,慢慢趋于稳定。随环境背压的降低和喷射压力的升高,小粒径的波峰逐渐增加,大粒径的波峰逐渐降低。不同喷射压力的喷雾粒径相对频率分布趋势均呈双峰分布。

“双碳”背景下可持续航空煤油的研究现状与展望

全球航空业年均排放约10亿t CO_(2)当量,约占全球总排放的2.8%。在“双碳”背景下,构建航空业脱碳体系、大力发展可再生能源在民航业的应用,已成为全球航空业重要的战略方向。简要论述了民用航空业的脱碳政策、现状、关键技术、存在问题及发展策略,发现航空业的可持续发展受制于其能源结构,面临严峻挑战,而可持续航空煤油是其中最有效、最可普及、最符合发展需求的减排方式。对可持续航空煤油的技术路径及其关键工艺进行详细论述,为民航业通过可持续航空煤油实现脱碳发展提供方向引导。

生物航煤产业发展现状与建议

民航业是运输业中减排难度较大的领域之一,除了研发飞机新技术、提高运营效率外,发展包括生物航煤在内的可持续航空燃料将是航空业实现净零目标的重要措施。总结了生物航煤产业的技术路线、供需市场、应用情况和政策形势,梳理了中国生物航煤产业发展面临的问题与挑战,认为中国废弃食用油等资源相对丰富,生物航煤生产潜力较大,产能投放计划较多,但国内消费市场仍未完全激发。提出了针对性建议:国家应加快构建生物航煤研发、生产、认证、应用、推广的全产业链;企业在保障原料获取稳定性的同时,可考虑发展综合型生物炼油厂,以提高整体经济效益。

航空动力领域氢能关键技术研究现状与趋势

航空业碳排放居高不下,随着其他产业去碳化加速,航空业碳排放占比将显著上升。氢能作为清洁能源,在航空领域具有巨大潜力,是实现航空业降碳目标的关键技术之一。本文综述了氢能在航空动力领域的应用现状,包括氢涡轮动力、氢燃料电池动力以及氢燃料航空内燃机等关键技术研究进展,分析了航空氢燃料存储技术(高温气态、低温液态、金属氢化物等)以及机场氢能基础设施建设等面临的挑战和解决方案,对氢气易燃易爆、易扩散、易造成氢脆等特性带来的安全隐患进行探究,并介绍了国际上在氢能安全方面的研究成果和经验。随着氢能技术的进步和全产业链成本的下降,氢能有望在航空业得到广泛应用,推动航空运输业实现低碳转型。

大型机载油箱电位分布与静电击穿仿真研究

低导电性的航空燃油在流经管路阀门等结构时会带有一定量的静电荷,这些静电荷最终会汇入燃油油箱。对于载油量较大的不规则飞机油箱,静电规律的数值计算与试验测量均不便展开。本文采用数值仿真软件COMSOL Multiphysics对油箱在充油过程中静电电位分布、静电放电电位和静电打火能进行仿真计算,并且对油位高度以及初始电荷密度对油箱静电放电及打火可能性的影响进行研究。通过计算充油过程中产生静电放电所需的最小击穿电压和产生静电带有的能量,对油箱内电位是否会引起静电击穿和引燃油箱内混合气体进行分析,为静电引起的油箱爆炸的风险评估提供了一种新思路。

国内外可持续航空燃料发展现状研究及相关政策建议

当前,我国航空业发展迅速,碳排放仍处于快速上升时期,通过可持续航空燃料(SAF)推动航空业降低碳排放对实现“双碳”目标意义重大。本文重点研究了SAF在降低航空业碳排放、打造新的绿色经济增长点、加快形成新质生产力等方面的诸多优势,分析了国际航空业降碳的主要路径、国外支持SAF发展的有关情况,以及我国SAF产业发展现状和潜力、面临的困难和挑战,建议从加强顶层设计、畅通产业链条、支持技术研发、建立自主体系等方面谋划布局,加快推动我国可持续航空燃料产业发展。