Theoretical and experimental study on the inhibition of jet fuel oxidation by diarylamine

Antioxidants addition is believed as a facile and effective way to improve jet fuel thermal oxidation stability.However,amine antioxidants,as one of the most important antioxidants,have not received sufficient attention in the field of jet fuel autoxidation yet.Herein,the inhibition efficiency and mechanism of decane and exo-tetrahydrodicyclopentadiene(THDCPD)oxidation by di-4-tert-butylphenylamine(diarylamine)was experimentally and theoretically investigated.The results show that diarylamine can significantly inhibit decane oxidation but is less efficient for THDCPD oxidation,which is attributed to the higher energy barrier of retro-carbonyl-ene reaction(rate-determining step)in THDCPD than that in decane during diarylamine regeneration.However,the addition of diarylamine will cause undesirable color change after accelerated oxidation and produce slightly more deposits during high-temperature thermal oxidative stress for both decane and THDCPD.The results provide significant implications for the future design of effective antioxidant additives for high-performance jet fuel.

Synthesis of high density and low freezing point jet fuels range cycloalkanes with cyclopentanone and lignin-derived vanillins

In this work,a“cyclopentanone-vanillin”strategy was proposed for the preparation of jet fuel range cycloalkanes from lignocellulose-derived ketones and lignin-derived aldehydes via aldol condensation and hydrodeoxygenation(HDO).Ethanolamine lactate ionic liquid(LAIL)exhibited excellent catalytic activity in the aldol condensation of cyclopentanone and vanillin.Desired mono-condensation and bicondensation products were obtained with yield of 95.2%at 100℃.It is found that the synergy effects between amino group of ethanolamine and hydroxyl group of lactic acid play a key role in the aldol condensation.The condensation products were converted into cycloalkanes by HDO over 5%Pd/Nb_(2)O_(5)catalyst.The density of the obtained HDO products is 0.89 g/cm^(3)and the freezing point is lower than-60℃.These results suggest that the resulted cycloalkanes can be used as additives to improve the density and low-temperature fluidity of the jet fuels.

Diesel and Jet Fuels from Bitumen-derived Middle Distillates

Narrow fractions of light gas oils obtained from various upgrading processes of Athabasca oilsands bitumen were investigated as diesel and jet fuels. The relationship among the boiling range, cetane number, smoke point, and other properties such as aromatics content, aniline point, and the sulfur and nitrogen content was also studied. The study reveals that when appropriate processes and distillation boiling ranges are selected, oilsands bitumen can produce diesel and jet fuels that meet stringent environmental regulations and future product specifications. New correlations to predict CN and smoke point were developed as a function of density, boiling ranges by simulated distillation, and mono- and total aromatics by supercritical fluid chromatography. The correlations apply to bitumen-derived middle distillates that have a wide range of boiling points.

Regulating the nanoscale intimacy of metal and acidic sites in Ru/γ-Al_(2)O_(3)for the selective conversions of lignin-derived phenols to jet fuels

Catalytic hydrodeoxygenation(HDO)of biomass-derived oxy-compounds to advanced hydrocarbon fuels usually requires bifunctional catalysts containing metals and acidic sites.The appropriate tuning of metal and/or acidic active sites at interfaces of bifunctional catalysts can significantly improve catalyst activity and product selectivity.Here,4-trifuoromethyl salicylic acid(TFMSA),as a hydrothermal stable organic acid,was employed to tailor the bifunctional interface of Ru/γ-Al_(2)O_(3)to enhance the catalytic performance on converting lignin-derived phenols to jet fuel range cycloalkanes.More than 80%phenol was converted into cyclohexane at 230°C for 1 h over Ru/γ-Al_(2)O_(3)modified by TFMSA,which was about three times higher than that over unmodified Ru/γ-Al_(2)O_(3).X-ray diffraction(XRD),Transmission electron microscope(TEM),H2 chemisorption,and energy dispersive X-ray spectroscopy(EDS)elemental mapping results indicated that Ru nanoparticles and TFMSA were well distributed onγ-Al_(2)O_(3),and a nanoscale intimacy between Ru and TFMSA was reached.Meanwhile,Fourier transform infrared spectroscopy after pyridine adsorption(Py-FT-IR)analysis proved that Brønsted acidic sites on the catalytic interfaces of TFMSA modified Ru/γ-Al_(2)O_(3)had been improved.Moreover,the kinetic and density functional theory(DFT)results suggested that the synergistic effects of adjacent Ru nanoparticles and acidic sites were crutial for promoting the rate-limiting conversion step of phenol HDO to cyclohexane.

Effects of Blending Long-Chain Alcohols with Jet Fuel on the Macroscopic Spray Characteristics

Long-chain alcohols were considered to be promising alternative fuels and fuel additives. This study was aimed at figuring out the influences of blending long-chain alcohols with jet fuel on the macroscopic spray characteristic. n-Butanol and n-pentanol were chosen as tested alternative fuels. A common-rail injection system was used to create high-pressure injection conditions. The Schlieren imaging system was used to capture spray processes. Results showed that with the addition of long-chain alcohols, the spray tip penetration and the peak spray tip velocity increased, whereas the spray cone angle and the spray area decreased. Comparisons between those macroscopic spray characteristics of AKB blends and AKP blends were also conducted. Compared to AKB blends, AKP blends showed similar spray tip penetration, larger peak tip velocity, smaller spray cone angle, and smaller spray area.

An experimental study on RP-3 jet fuel injection on a common rail injection system

RP-3 jet fuel could be an alternative fuel for diesel engines.In this study,the injection characteristics of RP-3jet fuel under single and split injection strategies were investigated and compared with diesel fuel.The experimental results indicate that RP-3 jet fuel has slightly shorter injection delay time than diesel fuel,but this difference is negligible in actual engine operations.Further,although the lower density and viscosity of RP-3 jet fuel lead to higher volumetric injection rates and cycle-based injection quantities,the cycle-based injection mass and the mass injection rates at the stable injection stage of RP-3 jet fuel are close to or slightly lower than those of diesel fuel.Based on these experimental observations,it could be concluded that fuel physical properties are the secondary factor influencing the injection characteristics in both single and split injection strategies,as RP-3 jet fuel and diesel fuel are taken for comparison.

Study on Using Mixed Fuel of Jet Fuel/Gasoline as Fuel of Gasoline Engine

This paper has integrated various methods such as laboratory physical and chemical analysis, engine bench test and actual road test, etc. to conduct a feasibility study on the emergency alternative fuel of gasoline by mixed jet fuel and gasoline. The study shows that both the evaporability and anti-knock quality decrease after mixing jet fuel with gasoline. While the mixing proportion increases, the engine power decreases and the fuel consumption increases gradually. When the proportion reaches 40%, the engine power drops by 5.3% to 11.7%, the fuel consumption rises by an average of 3.8%, and meantime the oil dilution and emission of the engine power become worse. Therefore, as for the gasoline engine, the mixed oil can only be used as emergency alternative fuel due to its harm to the engine.

Synthesis of jet fuel additive with cyclopentanone

A new route was developed for the synthesis of renewable decalin with cyclopentanone which can be derived from lignocellulose.It was found that 1,2,3,4,5,6,7,8-octahydronaphthalene could be selectively produced by the hydrogenation/dehydration/rearrangement of [1,1-bi(cyclopentylidene)]-2-one(i.e.the selfaldol condensation product of cyclopentanone) over a dual-bed catalyst system.Among the investigated catalysts,the Ru/C and Amberlyst-15 resin exhibited the highest activities for the hydrogenation of [1,1-bi(cyclopentylidene)]-2-one to [1,1-bi(cyclopentan)]-2-ol and the dehydration/rearrangement of [1,1-bi(cyclopentan)]-2-ol to 1,2,3,4,5,6,7,8-octahydronaphthalene,respectively.Using Ru/C and Amberlyst-15 resin as the first bed and the second bed catalysts,1,2,3,4,5,6,7,8-octahydronaphthalene was directly produced in high carbon yield(83.7%) under mild conditions(393 K,1 MPa).After being hydrogenated,the1,2,3,4,5,6,7,8-octahydronaphthalene was converted to decalin which can be used as additive to improve the thermal stability and volumetric heat value of jet fuel.

Experimental and Molecular Simulations for Evaluating the Effect of Lubricity Improvers on the Property of Jet Fuel

Since the 1990 s, the kerosene fuel(code: JP-8) had been applied in the ground equipment provided with direct injection compression ignition engines in the U.S. Army, resulting in increased occurrence of injection pump failures. Anti-wear additives must be used in the single fuel due to its poor lubricity. In the present work, lubricity improvers were selected on the basis of molecular simulation theoretically and these agents were evaluated to improve the lubricity of jet fuel using the high frequency reciprocating rig(HFRR) apparatus and the ball-on-cylinder lubricity evaluator(BOCLE). It was revealed that dimer acid with higher value of adsorption energy on the Fe(110) plane surface had more efficient lubricity promoting properties than that of naphthenic acid. The experimental results suggested that the dimer acid had a better tribological behavior compared with that of naphthenic acid used as lubricity improver of jet fuel. And addition of anti-wear additives at a dosage of 15 μg/g was able to promote the lubricity of jet fuel to a required level on BOCLE, while a higher concentration over 80 μg/g was needed to improve the lubricity to a demanded value of diesel on HFRR.

Hydrothermal liquefaction of biomass for jet fuel precursors:A review

Climate change is an important issue facing the world today and carbon reduction has become the fo-cus of attention for all countries.Alternative bio-fuels are an important means to achieve carbon emis-sion reduction.The production of jet fuel precursors from biomass by hydrothermal liquefaction(HTL)has received a lot of attention due to its mild conditions and environmental friendliness.Lignocellulosic biomass and algal biomass are considered as the second and the third generation biomasses as promising raw materials for alternative fuel preparation.Among them,lignocellulosic biomass has been extensively studied due to its wide range of sources and can be divided into one-step HTL and stepwise HTL accord-ing to the process method.Algal biomass has been extensively studied experimentally due to its short growth cycle and the fact that it can sequester large amounts of carbon without taking up arable land.In this paper,the feedstock composition of different biomasses is reviewed for the HTL of biomass.A detailed review of the process characteristics,reaction pathways and influencing factors for the HTL pro-duction of jet fuel precursors from lignocellulosic biomass and algal biomass is also presented.Theoretical references are provided for further process optimization and bio-crude quality upgrading.

MCM-22 zeolite-based system to produce jet fuel from the 1-hexene oligomerization

The oligomerization of light olefins is an alternative for generating clean liquid fuels.In this study,the MCM-22 zeolite featuring a partially disordered layered structure with framework combined 10 membered ring(10 MR)was discussed for 1-hexene oligomerization.MCM-22 and Y zeolite were compared to investigate the influences of the framework and acidity strength on the activity and yield in the 1-hexene oligomerization.The results indicated that the MCM-22 zeolite was an efficient catalyst for oligomerization compared to Y zeolite.The MCM-22 zeolite was characterized in detail by NMR,Py-FTIR,and TG analyses.The catalytic performance and deactivation properties of MCM-22 zeolite in the oligomerization reaction of 1-hexene were investigated.Structure-activity relationships were established through the kinetic study.Although the density of strong acid sites was essential for the oligomerization of 1-hexene,the presence of low pressure was also necessary for the formation of dimers.Thus,MCM-22 zeolite demonstrates a substantial improvement in initial conversion and catalyst lifespan for 1-hexene oligomerization.

Combustion and emissions of RP-3 jet fuel and diesel fuel in a single-cylinder diesel engine

The combustion characteristics and emission behaviors of RP-3 jet fuel were studied and compared to commercial diesel fuel in a single-cylinder compression ignition(CI)engine.Engine operational parameters,including engine load(0.6,0.7,and 0.8 MPa indicating the mean effective pressure(IMEP)),the exhaust gas recirculation(EGR)rate(0%,10%,20%,and 30%),and the fuel injection timing(–20,–15,–10,and–5°crank angle(CA)after top dead center(ATDC))were adjusted to evaluate the engine performances of RP-3 jet fuel under changed operation conditions.In comparison to diesel fuel,RP-3 jet fuel shows a retarded heat release and lagged combustion phase,which is more obvious under heavy EGR rate conditions.In addition,the higher premixed combustion fraction of RP-3 jet fuel leads to a higher first-stage heat release peak than diesel fuel under all testing conditions.As a result,RP-3 jet fuel features a longer ignition delay(ID)time,a shorter combustion duration(CD),and an earlier CA50 than diesel fuel.The experimental results manifest that RP-3 jet fuel has a slightly lower indicated thermal efficiency(ITE)compared to diesel fuel,but the ITE difference becomes less noticeable under large EGR rate conditions.Compared with diesel fuel,the nitrogen oxides(NOx)emissions of RP-3 jet fuel are higher while its soot emissions are lower.The NOx emissions of RP-3 can be effectively reduced with the increased EGR rate and delayed injection timing.

Spray Characteristics of RP-3 Jet Fuel at Non-Evaporating and Evaporating Environments

Spray experiments of RP-3 jet fuel at non-evaporating and evaporating environments were studied on a constant volume spray chamber,and diffusive back-imaging technique was used to capture the transient spray development processes.Spray tip penetration,projected spray area and cone angle of RP-3 jet fuel were derived from the spray development images,and compared to those of diesel fuel.It is observed that non-evaporating sprays of RP-3 jet fuel and diesel fuel do not exhibit significant differences,as their spray penetration distances,projected spray areas and spray cone angles are consistent at most test conditions.The evaporating sprays of RP-3 jet fuel produce shorter liquid-phase penetration distances and lower projected spray areas than those of diesel fuel,and these differences are particularly pronounced at low ambient temperatures.However,fuel effects on the evaporating spray cone angle are insignificant.Further,increased ambient density or ambient temperature shortens the liquid-phase spray penetration distance and reduces the liquid-phase spray area,and these effects are more pronounced for diesel fuel than RP-3 jet fuel.

An experimental study on spray auto-ignition of RP-3 jet fuel and its surrogates

Jet fuel is widely used in air transportation,and sometimes for special vehicles in ground transportation.In the latter case,fuel spray auto-ignition behavior is an important index for engine operation reliability.Surrogate fuel is usually used for fundamental combustion study due to the complex composition of practical fuels.As for jet fuels,two-component or three-component surrogate is usually selected to emulate practical fuels.The spray auto-ignition characteristics of RP-3 jet fuel and its three surrogates,the 70%mol n-decane/30%mol 1,2,4-trimethylbenzene blend(Surrogate 1),the 51%mol n-decane/49%mol 1,2,4-trimethylbenzene blend(Surrogate 2),and the 49.8%mol n-dodecane/21.6%mol iso-cetane/28.6%mol toluene blend(Surrogate 3)were studied in a heated constant volume combustion chamber.Surrogate 1 and Surrogate 2 possess the same components,but their blending percentages are different,as the two surrogates were designed to capture the H/C ratio(Surrogate 1)and DCN(Surrogate 2)of RP-3 jet fuel,respectively.Surrogate 3 could emulate more physiochemical properties of RP-3 jet fuel,including molecular weight,H/C ratio and DCN.Experimental results indicate that Surrogate 1 overestimates the auto-ignition propensity of RP-3 jet fuel,whereas Surrogates 2 and 3 show quite similar auto-ignition propensity with RP-3 jet fuel.Therefore,to capture the spray auto-ignition behaviors,DCN is the most important parameter to match when designing the surrogate formulation.However,as the ambient temperature changes,the surrogates matching DCN may still show some differences from the RP-3 jet fuel,e.g.,the first-stage heat release influenced by low-temperature chemistry.

Formation of coke in thermal cracking of jet fuel under supercritical conditions

Continuous-flow reactor experiments were carried out to study coke formation from thermal crack-ing of home-made jet fuel RP-3 under supercritical con-ditions.The mechanism and precursor of coke forming were analyzed.The starting cracking temperature of RP-3 fuel was determined to be 471.8uC by differential scan-ning calorimetry(DSC).Temperature-programmed oxidation and scanning electron microscopy(SEM)characterizations of the stressed tubes showed that there are three different coke species including chemisorbed carbon,amorphous carbon and filamentous coke in the solid deposits.More than 90%of coke deposits are carried away by the supercritical fluid,which has strong capabilities of extraction for coke deposits and their pre-cursors.There were 17.1 wt-%of iron and 11.1 wt-%of chromium found on the coke surface detected by energy dispersive spectroscopy(EDS)which suggests carbure-tion on alloy.RP-3 fuel and its cracking liquids were analyzed by GC-MS,which showed that the content of alkyl benzene and alkyl naphthalene increased evidently in cracking liquids.

油脂加氢生产生物喷气燃料(SRJET)技术及工业应用

为了保障中国航空业市场对生物喷气燃料的需求,中国石化镇海炼化分公司(简称镇海炼化)采用中石化石油化工科学研究院有限公司开发的油脂加氢生产生物喷气燃料(SRJET)技术新建一套100 kt a以餐饮废油为原料的生物喷气燃料生产装置,该装置一次开车成功,生产的生物喷气燃料产品满足《3号喷气燃料》(GB 6537-2018)附录C酯类和脂肪酸类加氢改质工艺生产的煤油组分标准中各项指标的要求,成功获得可持续生物材料圆桌会议颁发的可持续认证证书和中国民用航空局审定的生物喷气燃料适航证书,并成功实现商业飞行。

Theoretical design and preparation of high thermal-stable jet fuel

A high thermal-stable jet fuel design method was developed using composition-properties relations and basic specification properties of jet fuel. Tannery diagrams were provided to visualize relationships among three main components (n-paraffins, iso-paraffins, cycloparaffins, or aromatics) with four major specification properties (density, flash point, freezing point, net heat of combustion) and thermal sta- bility. An optimum chemical composition was established to meet performance requirements: n-paraffins 25%-45%, iso-paraffins 15%-30%, cycloparaffins 30%-50%, and aromatics 5%. The thermal stability test on four fuel samples with and without optimal composition indicated that the thermal stabilities of fuel samples with optimal composition are higher than RP-3 jet fuel, and that the theoretical design method is a reliable method to screen the basic oil for the high thermal-stable jet fuel.

Characteristics of a coherent jet enshrouded in a supersonic fuel gas

Based on a current coherent jet,this study proposes a supersonic combustion(SC)coherent jet in which the main oxygen jet is surrounded by a supersonic fuel gas.The characteristics of the proposed coherent jet are analyzed using experimental methods and numerical simulations in the high-temperature environment of electric arc furnace(EAF)steelmaking.The SC coherent jet achieved stable combustion in the EAF steelmaking environment.The simulated combustion temperature of the supersonic shrouding methane gas was 2930 K,slightly below the theoretical combustion temperature of methane–oxygen gas.The high speed and temperature of the supersonic flame effectively weakened the interaction between the main oxygen jet and the external ambient gas,inhibiting the radial expansion of the main oxygen jet and maintaining its high speed and low turbulence over a long distance.These features improved the impact capacity of the coherent jet and strengthened the stirring intensity in the EAF bath.

静电场作用下航煤氧化结焦过程分析

航空发动机燃烧室工作环境恶劣,导致燃油组分同溶解氧反应引发氧化沉积.通过对金属平板表面沉积的研究,分析电场对氧化结焦过程的影响.搭建了金属平板氧化结焦实验系统,对不同物理条件和电场性质下的结焦情况进行分析.研究表明:随着温度升高、表面粗糙度增加,结焦量增多;金属对焦体有催化作用而改变结焦形貌;电场的加入使焦体颗粒的粒径和融并现象发生变化,采用负电场时,表面结焦量大幅降低,焦体内部元素含量和结构发生改变,电场强度使结焦颗粒间排斥作用增大,抑制结焦过程,采用正电场时由于电场方向的改变促进了沉积向壁面的移动,使结焦量增加.

典型添加剂对3号喷气燃料热氧化安定性的影响原因分析及对策

热氧化安定性是喷气燃料的一项重要性能指标。抗静电剂和抗磨剂是工业喷气燃料调和过程中必须要加入的两种添加剂,而在市场中常用的添加剂分别是抗静电剂Stadis和抗磨剂T-1602。通过研究抗静电剂Stadis和抗磨剂T-1602对喷气燃料热氧化安定性的影响因素,包括空气、光照、存储温度等条件,对喷气燃料在实际生产过程中的调和、存储和使用安全都有非常重要的意义。研究结果表明:抗静电剂Stadis对喷气燃料热氧化安定性基本没有影响。抗磨剂T-1602影响喷气燃料热氧化安定性的因素有含氧的环境、光照、储存温度、添加剂浓度和储存材质等。随着储存温度的升高,含抗磨剂喷气燃料母液的热氧化安定性变差。随着抗磨剂添加浓度逐渐提高,含抗磨剂母液的喷气燃料热氧化安定性逐渐下降。通过采取对喷气燃料配置过程中增加氮封隔绝空气、避免光照、罐存储温度按照不大于40℃等措施,可最大程度降低喷气燃料热氧化安定性超标的质量风险,为喷气燃料的安全使用提供合理保障。