JOURNAL OF CHEMICAL THERMODYNAMICS
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2020
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IF 2.888
Qi Zhou,Taotao Zhan,Junshuai Chen,Maogang He,Ying Zhang
n -Decane is a major ingredient of many transportation fuels, and is widely used as the additive in engineering domain. To supplement the existing database, the speed of sound in n -decane was measured along five isobaric lines from (0.1 to 10) MPa and at temperatures between (298.32 and 653.93) K by the Brillouin light scattering method. With the level of confidence of 0.95 (coverage factor k = 2), the relative expanded uncertainty of our measurement system and that of the experimental speed of sound in n -decane were estimated to be less than 1.1% and 1.7%, respectively. Besides, the absolute average percentage deviation and the maximum deviation of the experimental results from values calculated with the recommended fundamental equation in the NIST Standard Reference Database 23 were found to be 1.0% and 4.4%, respectively. At the end, for temperatures between (303.15 and 373.15) K and at pressures up to 10 MPa, the derived properties of n -decane including density, isobaric heat capacity, isobaric thermal expansion, isothermal compressibility, isentropic compressibility and internal pressure were studied.
研究领域:
物理化学
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工程热力学
✓ 已验证
产品关联
DOI
高影响因子
FLUID PHASE EQUILIBRIA
·
2017
·
IF 2.473
Kai Kang,Xiaopo Wang
The experimental measurements for liquid densities of n -decane and p -xylene binary mixtures were performed over the entire composition with a high-pressure vibrating-tube densimeter. The temperature ranges for the present measurement were from 293.15 K to 363.15 K and the pressures were reached to 60 MPa. The experimental uncertainty is estimated to be 0.001 with 0.95 confidence level. Experimental density values were fitted by the modified Tammann–Tait equation. The PC-SAFT equation of state and Cibulka's equation was used to predict the densities of n -decane and p -xylene and its mixtures. In addition, derived volumetric properties, such as the excess molar volumes , the isothermal compressibility , and isobaric thermal expansivity, were calculated from the experimental density data. The effects of pressure and temperature on the derived properties were also discussed.
研究领域:
化学工程
·
热力学
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2023
·
IF 7.4
Wenrui Yan,Lu Liu,Liuru Liu,Quan Zhu,Bo Wang
The coking problem of hydrocarbon fuel pyrolysis is the key factor affecting the application of active cooling technology for high-speed aircraft. The purpose of this work is to investigate the coking inhibition performance and coking mechanism of using ammonia as an additive during the thermal cracking. In this study, the pyrolysis and coking characteristics of supercritical n-decane were experimentally studied using an electrically heated tube. ICP-OES (Inductively Coupled Plasma Optical Emission Spectrometer), GC–MS (Gas Chromatograph Mass Spectrometer), SEM (Scanning Electron Microscope), EDS (Energy Dispersive Spectroscopy), TPO (Temperature Programmed Oxidation), and Raman spectroscopy are applied to characterize the anti-coking performance of the additives. The results show that the additive hardly affects the cracking of the fuel under high-temperature conditions, but the coke mass deposited on the inner surface of the tube is significantly reduced, and the coking inhibition rate can reach 80% at 750 °C. The addition of additives reduced the graphitization degree and oxidative activity of the coke. The maximum oxidation temperature of the coke obtained at 750 °C was reduced by 145 °C, and the I D /I G value of the Raman spectroscopy peak-fitting was 3.29. The new mechanism of the effect of additives on the formation of coking precursors and the deposition of coke on the surface of the tube wall is proposed. Ammonia can react with Ni of the inner metal tube and radicals generated by fuel cracking to form a carbonized film, achieving the effect of inhibiting metal catalytic coking. Meanwhile, the amino radicals generated by ammonia dehydrogenation can regulate the coking reaction path by forming a stable p - π conjugate structure with unsaturated radicals. Therefore, the research will contribute to a deeper comprehension of the coking inhibition mechanism and the development of more effective coking inhibitors, providing new technical support for active cooling technologies.
研究领域:
化学工程
·
能源科学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Wenrui Yan,Xinke Wang,Jianhua Dong,Yu Liu,Liuru Liu,Bo Wang,Quan Zhu
The active cooling technology based on endothermic hydrocarbon fuels can cause serious coking problems. Ammonia addition inhibits the coke formation at the mild fuel cracking. However, the mechanism of coke deposition under higher fuel conversion conditions remains unclear. Herein, the deep pyrolysis experiments of n-decane with ammonia addition was conducted using the electric heating method. The anti-coking performances of additives were obtained from the coking characteristics at different pyrolysis stages. The results indicate that under deep cracking conditions, the additive reacts with unsaturated free radicals produced by fuel cracking to produce aromatic heterocyclic compounds, inhibiting the formation and growth of polycyclic aromatic hydrocarbons (PAHs), thereby reducing the content of coking precursors. More importantly, the C-N compounds interact with the metals to form the spherical carbon with a predominant diamond structure, depositing as a thin film with passivation effect. As the reaction time proceeds, the film gradually smooths and maintains a thickness of about 4 μ m . In addition, passivation coating of TiN is used to further evaluate the effect of additives on the formation of surface coke. These results reveal that ammonia can ensure effective coking inhibition under long-term deep cracking conditions by affecting the growth of PAHs and coke surface.
研究领域:
化学工程
·
能源科学
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2023
·
IF 7.4
Fanggang Zhang,Sheng Su,Juan Wang
Aiming to achieve efficient utilization of high-energy–density fuels in the promising portable power systems, self-sustained combustion of n-decane over Co 3 O 4 -based catalysts in a narrow quartz reactor was investigated. Chemiluminescence, gas chromatography and various physicochemical characterization methods were used in this study. The evidences suggest that Co 3 O 4 -based catalysts can significantly reduce the ignition temperature and broaden the flammability limits of n-decane. The heat release stored in the catalyst bed can help improve the flame stability, delay the flame extinction, and achieve auto-ignition without forced heating. Besides, great promotion of the catalytic performance of Co 3 O 4 spinel is achieved by doping with 6 wt% PdO. PdO/Co 3 O 4 catalysts exhibit higher activity and enhanced ability in effectual resistance toward deactivate than pure Co 3 O 4 . Furthermore, the coupling of heterogeneous and homogeneous reactions of n-decane has been analyzed. It can be revealed that both the adsorbed and gaseous OH* radicals play greatly different roles when using different catalysts. These findings promote the use of heavy hydrocarbon fuels for energy supply and contribute to designing efficient Co 3 O 4 -based catalysts rationally.
研究领域:
化学工程
·
催化科学
✓ 已验证
DOI
高影响因子
FLUID PHASE EQUILIBRIA
·
2021
·
IF 2.775
Xiong Zheng,Dan Qu,Fa Zhang,Yu Liu,Guangzhao Qin
Hydrocarbons play an important role in lots of industrial processes. Thermal conductivity is an important thermophysical property of fluids in energy conversion process, such as the design of the heat transfer system and the evaluation of thermodynamic cycle. Thus, it is of great significance to acquire solid experimental data and develop reliable models for achieving accurate thermal conductivity of hydrocarbons. In this work, thermal conductivity of two common fuels, n-octane and n-decane, were studied by combining experimental and theoretical methods. Using the transient hot wire method, the thermal conductivity is measured with temperature ranging from 303 to 523 K and pressures ranging from 0.1 to 15 MPa. Excellent agreement is achieved by comparing our experimental results with literatures. Furthermore, the mechanism for the influence of temperature and pressure on thermal conductivity of liquid n-octane and n-decane was explored preliminarily based on Bridgman's theory. In addition, we proposed a modified model considering the critical thermal conductivity enhancement, with which the average absolute deviations are 0.49% and 0.43% for n-octane and n-decane, respectively. It is shown that our proposed model has better predictive ability for representing thermal conductivity than the four traditional theoretical models (Assael model, Sun and Teja model, Huber and Perkins model, Liu model), especially at the vicinity of the critical point. The achievements in the present study are not only useful for relevant industrial application but also helpful for understanding the thermal conductivity critical enhancement when approaching the liquid-gas critical point for n-alkanes.
研究领域:
化学工程
·
热物理
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF CHEMICAL AND ENGINEERING DATA
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2020
·
IF 2.369
Xiaolin Zhao,Ji Mi,Yitong Dai,Guijin He,Yongsheng Guo,Wenjun Fang
exo-Tetrahydrodicyclopentadiene can serve as both the propellant and coolant in hypersonic vehicles. However, its applications are restricted by the poor properties of ignition and combustion to some extent. Fuel additives such as appropriate alcohols have the ability to overcome these deficits. Research on thermophysical properties of the mixtures composed of exo-tetrahydrodicyclopentadiene and fuel additives can provide important information for the research of fuel additives. In this work, densities and viscosities of the ternary system of exo-tetrahydrodicyclopentadiene (1) + n-decane (2) + iso-butanol (3) and three corresponding binary systems have been measured over the whole composition range in the temperature range from 293.15 to 333.15 K with an interval of 5 K and at pressure p = 0.1 MPa. The values of excess molar volumes (VmE) and viscosity deviations (Δη) of three binary systems and the ternary system were calculated and then fitted to the Redlich–Kister equation and four semi-empirical equations, respectively. The variations of VmE and Δη were explained from the viewpoints of intermolecular forces and structural effects. Furthermore, the Jouyban–Acree model was used to correlate the values of densities (ρ) and viscosities (η) of the studied mixtures with high accuracy.
研究领域:
物理化学
·
燃料工程
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2023
·
IF 7.4
Yu Feng,Huihang Zhang,Deming Zhang,Fuqiang Chen,Xinhai Xu,Jiang Qin,Yi Jiao
The cracking of on-board hydrocarbon fuels is a strong endothermic reaction and can provide an additional chemical heat sink in the cooling process of the hypersonic vehicle. However, the cooling capacity of current hydrocarbon fuels can hardly meet the cooling requirements of the hypersonic vehicle at higher flight speeds. Blending ethanol is an effective method to improve the chemical heat sink of hydrocarbon fuels, but the mechanism of ethanol on chemical heat sink is unclear. In this study, n-decane was selected as a model compound of hydrocarbon fuels to investigate the physical and chemical effect of ethanol on the chemical heat sink of n-decane cracking by analyzing the chemical reactions involved through experimental study and chemical dynamic simulation. The results indicate that there is an optimum ethanol blend ratio to achieve the maximum chemical heat sink. The carbon monoxide methanation reaction which is an exothermic reaction can deteriorate endothermic process at 300–375 °C. With ethanol blending ratio above 20 wt%, ethanol vaporization deteriorates chemical heat sink by reducing the residence time in the temperature range of 225–250 °C. Pressure can suppress the reduction of residence time caused by ethanol evaporation and also suppress the positive reaction of ethanol cracking. The kinetic model of ethanol and n-decane mixture cracking was established. The calculated results verify that ethanol cracking ( C 2 H 5 OH =CO+ C H 4 + H 2 ) and methane cracking ( C H 4 =C+ 2H 2 ) are dominant reactions in ethanol-assisted n-decane thermal cracking below 475 °C.
研究领域:
能源科学
·
化学工程
·
航空航天工程
✓ 已验证
DOI
高影响因子
FUEL
·
2023
·
IF 7.4
Bo Wang,Wenrui Yan,Xianlong Gong,Quan Zhu
Coking during the endothermic hydrocarbon fuel pyrolysis is a key issue that needs to be solved in the development of regenerative cooling technology for high-speed aircrafts. The compounds containing hydroxyl groups are developed to inhibit coking by regulating coking pathway during the thermal cracking of hydrocarbon fuels. Pyrolytic deposition experiments of n -decane with additives were performed using the method of electrical heating. The anti-coking performance of the additives was characterized by means of gas chromatograph–mass spectrometer (GC–MS), scanning electron microscopy (SEM), temperature programmed oxidation (TPO) and Raman spectroscopy. The results showed that the degree of cracking is reduced at low fuel temperature due to the dilution of the additives, and the additives do not affect the fuel cracking as the fuel temperature increased. With the function of additives, the masses of filamentous and amorphous coke were decreased. A possible mechanism for the additives inhibiting coking has been proposed. The additives containing hydroxyl groups can block the initial coking reaction path to inhibit coking at the source. In general, the hydroxyl radicals released by the additives oxidize the coking precursors to prevent its further growth, and react with the substrate to form particulate matters serving as passivation coating, inhibiting the bulk phase coking and metal catalytic coking simultaneously. This work provides significant ideas for inhibiting coking by regulating coking reaction pathways.
研究领域:
化学工程
·
航空航天材料科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF SOLID STATE CHEMISTRY
·
2019
·
IF 2.291
Yu Sang,Hansheng Li
The objective of this work is to investigate the catalytic effect of a series of modified HZSM-5 zeolites on n-decane cracking at 500 °C and atmospheric pressure. The zeolite catalysts were prepared with phosphorus and/or mesopore modification by excessive impregnation and/or hydrothermal treatment , and were characterized with various methods including SEM, TEM , XRD , FTIR, N 2 adsorption-desorption measurement and NH 3 -TPD. Results show that the addition of phosphorus adjusted the distribution and strength of acid sites in the zeolite crystals. The introduced mesoporous structure improved the diffusion of reactants and products in zeolite pores during n-decane cracking. With appropriate acid amounts and distribution, as well as short channels and high specific surface area, the modified HZSM-5 nanoparticles exhibited higher catalytic activity, better light olefins selectivity and longer lifetime, compared with the original HZSM-5 zeolite. The phosphorus modified HZSM-5 zeolites coupling with MCM-41 matrix was proved to be a promising catalyst for the thermal cracking of n-decane.
研究领域:
催化化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2022
·
IF 8.035
Shengrong Xie,Xing Li,Tao Li,Jiepeng Huo,Junxiong Wang,Chenguang Wang,Xiaohan Wang
The laminar burning velocities (LBVs) of n-decane/toluene/air mixtures were measured at elevated temperatures using externally heated diverging channel (EHDC) method. The effects of initial temperature (up to 650 K), toluene blending ratio ( R C7H8 = 0 to 1.0 by liquid volume) and equivalence ratio ( ϕ = 0.6 to 1.4) on the LBVs of n-decane/toluene/air mixtures have been investigated. Numerical computation with a detailed reaction mechanism was used to further analyze the effects of potential interactions between n-decane and toluene. It was observed that the LBVs of n-decane/toluene/air mixtures increase with the increase of initial temperature, while the LBVs decrease with the increase of toluene blending ratio. The effects of toluene on the LBVs through chemical reactions, heat and mass transfer were analyzed in detail. Moreover, the temperature compensation method, which separates the effect of adiabatic flame temperature and contribution from chemical and disunion, was used in analysis. The effects of the toluene blending on the LBV is mainly attributed to chemical term, and the thermal effect have a second order importance. The reaction pathways and sensitivity analysis show that the LBVs of stoichiometric mixtures is less sensitive to kinetic coupling. The distinct flame propagation properties of the n-decane/toluene blended fuels are determined by the distributions of reaction rates of the crucial intermediate species and radicals.
研究领域:
燃烧学
·
化学动力学
✓ 已验证
产品关联
DOI
高影响因子
ENERGY & FUELS
·
2014
·
IF 2.733
Zhenjian Jia,Hongyan Huang,Weixing Zhou,Fei Qi,Meirong Zeng
The pyrolysis mechanism of fuel under supercritical conditions is an important concern for developing regenerative cooling technology of advanced aircraft using hydrocarbon fuel as the primary coolant. n-Decane as a component of some jet fuels was studied at the temperature range from 773 to 943 K in a flow reactor under the pressure of 3, 4, and 5 MPa. Gas chromatograph/mass spectrometry was used to analyze the pyrolysis products, which were mainly alkanes from C1–C9 and alkenes from C2–C9. A kinetic model containing 164 species and 842 reactions has been developed and validated by the experimental results including the distributions of products and the chemical heat sink of fuel. The decomposition pathways of n-decane were illustrated through the reaction flux analysis. It is concluded that the C4–C9 alkanes are mainly generated by the recombinations of alkyls, while the small alkanes (C1–C3) are formed by H-abstraction reactions by C1–C3 alkyl radicals. The applicability at supercritical pressure and high fuel concentration condition of previous models was discussed, and the performance of the present model in reproducing the experimental data is reasonably good.
研究领域:
化学工程
·
航空工程
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）