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  • Experimental investigation on effect of ethanol and di-ethyl ether addition on the spray characteristics of diesel/biodiesel blends under high injection pressure
    Fuel (IF 4.601) Pub Date : 2018-01-11
    Cheng Zhan, Zehao Feng, Wen'an Ma, Mingzhi Zhang, Chenglong Tang, Zuohua Huang

    In this work, a comprehensive experimental investigation on spray characteristics of four blended fuels, including diesel (D100), diesel-biodiesel (DB), diesel-biodiesel- ethanol (DBE), and diesel-biodiesel-diethyl ether (DBDE) has been conducted by using high pressure common rail injection system (up to 200 MPa). The transient spray behavior under various conditions was recorded by high speed photography with scattering light illumination. It is shown that higher injection pressure significantly accelerates the spray tip penetration (STP) evolution due to increased inertia of spray while increase in ambient pressure reduces the STP evolution due to higher gas resistance. With the addition of diethyl ether (DEE) into biodiesel, the STP of blended fuel tends to go down and corresponding projected area increases a lot when compared to DB. By means of particle droplet image analysis (PDIA) optical diagnostic method, spray microscopic parameters such as Sauter Mean Diameter (SMD), droplet diameter distribution probability curve, cumulative volume curve and characteristic diameter have been investigated. Results show that both the injection pressure and ambient pressure have significant influence on the spray microscopic characteristics. In addition, for fixed injection pressure and ambient pressure, when DEE is added into DB blends, the number fraction of smaller droplets increases, though the statistic diameter with peak probability is fixed at a certain value. Furthermore, SMD of the four tested fuels decreases sequentially in the order of DB, D100, DBE, and DBDE, indicating that DEE addition favors the atomization process.

    更新日期:2018-01-17
  • Viscosity models for pure hydrocarbons at extreme conditions: A review and comparative study
    Fuel (IF 4.601) Pub Date : 2018-01-12
    Hseen O. Baled, Isaac K. Gamwo, Robert M. Enick, Mark A. McHugh

    Viscosity is a critical fundamental property required in many applications in the chemical and oil industries. In this review the performance of seven select viscosity models, representative of various predictive and correlative approaches, is discussed and evaluated by comparison to experimental data of 52 pure hydrocarbons including straight-chain alkanes, branched alkanes, cycloalkanes, and aromatics. This analysis considers viscosity data to extremely high-temperature, high-pressure conditions up to 573 K and 300 MPa. Unsatisfactory results are found, particularly at high pressures, with the Chung-Ajlan-Lee-Starling, Pedersen-Fredenslund, and Lohrenz-Bray-Clark models commonly used for oil reservoir simulation. If sufficient experimental viscosity data are readily available to determine model-specific parameters, the free volume theory and the expanded fluid theory models provide generally comparable results that are superior to those obtained with the friction theory, particularly at pressures higher than 100 MPa. Otherwise, the entropy scaling method by Lötgering-Lin and Gross is recommended as the best predictive model.

    更新日期:2018-01-17
  • Experimental study on impingement spray and near-field spray characteristics under high-pressure cross-flow conditions
    Fuel (IF 4.601) Pub Date : 2018-01-12
    Zhanbo Si, Nagisa Shimasaki, Keiya Nishida, Youichi Ogata, Min Guo, Chenglong Tang, Zuohua Huang

    The fuel spray injected into a direct injection (DI) engine is substantially affected by both the in-cylinder air flow and the piston cavity wall impingement. The combined effect of the air flow and the wall impingement plays an important role on the spray development, mixture formation, and subsequent combustion. In this study, the effects of cross-flow and flat wall impingement on the spray development and dispersion were investigated. The spray was injected by a valve covered orifice (VCO) nozzle under various cross-flow velocities and ambient pressures. Impingement spray images in a vertical plane and several horizontal planes were obtained by a high speed video camera and a continuous wave laser sheet. A high speed video camera connected with a long-distance microscope was employed to obtain the near-field spray images. The results show that cross-flow favors spray dispersion while the high ambient pressure tends to compress the spray profiles. Additionally, under an approximate liquid-to-air momentum flux ratio q, when the ambient pressure and cross-flow velocity were varied, at 2 ms ASOI the outlines of the spray in the windward side agree well, whereas the spray extended further in the leeward side at a lower ambient pressure. At the plane of y = 25 mm, a complex vortex movement was observed that resulted in a non-uniform distribution of droplets in the upper part of the spray in the leeward side. In addition, at the plane of y = 45 mm, an empty belt area occurred in the vortex core region revealing that the density of the droplets in this region was quite low. The quantitative analysis shows that with increasing cross-flow velocity, the spray tip penetration decreases slightly before impingement while the spray tip penetrates further on the wall surface after impingement. The high cross-flow velocity favors the spray breakup and dispersion leading to a larger wall-jet vortex while the high ambient pressure restrains the spray dispersion leading to a smaller spray tip penetration and vortex height. For near-field spray, the spray image at higher ambient pressure shows fewer ligaments. With increasing cross-flow velocity, the whole spray shifted downstream. The spray outline was wider at the initial stage (0.05 ms ASOI) than that at steady stage (2 ms ASOI) of spray evolution.

    更新日期:2018-01-17
  • Nanoscale rock mechanical property changes in heterogeneous coal after water adsorption
    Fuel (IF 4.601) Pub Date : 2018-01-12
    Yihuai Zhang, Maxim Lebedev, Ahmed Al-Yaseri, Hongyan Yu, Xiaomeng Xu, Mohammad Sarmadivaleh, Ahmed Barifcani, Stefan Iglauer

    Rock mechanical properties are of key importance in coal mining exploration, coal bed methane production and CO2 storage in deep unmineable coal seams; accurate data is required so that geohazards (e.g. layer collapse or methane/CO2 leakage) can be avoided. In this context it is well established that coal matrix swelling due to water adsorption significantly changes the coal microstructure. However, how water adsorption and the associated with microstructural changes affect the mechanical properties is only poorly understood, despite the fact that micro-scale mechanical properties determine the overall geo-mechanical response as failure initiates at the weakest point. Thus, we measured nanoscale rock mechanical properties via nanoindentation tests and compared the results with traditional acoustic methods on heterogeneous medium rank coal samples in both dry and brine saturated conditions. The microscale heterogeneity of the rock mechanical properties was mapped and compared with the morphology of the sample (measured by SEM and microCT). While the nanoindentation tests measured decreasing indentation moduli after water adsorption (−60% to −66%), the traditional acoustic tests measured an increase (+17%). We concluded that acoustic tests failed to capture the accurate rock mechanical properties changes for the heterogeneous coal during water adsorption. It is thus necessary to measure the coal rock mechanical properties at the microscale to obtain more accurate data and reduce the risk of geohazards.

    更新日期:2018-01-17
  • Enhancing energy production from waste textile by hydrolysis of synthetic parts
    Fuel (IF 4.601) Pub Date : 2018-01-12
    Elnaz Hasanzadeh, Safoora Mirmohamadsadeghi, Keikhosro Karimi
    更新日期:2018-01-17
  • Morphological and structural evolution of bituminous coal slime particles during the process of combustion
    Fuel (IF 4.601) Pub Date : 2018-01-12
    Hui Wang, Songlin Liu, Xiaotong Li, Dawei Yang, Xiangyu Wang, Chang Song
    更新日期:2018-01-17
  • Catalytic cracking of Swida wilsoniana oil for hydrocarbon biofuel over Cu-modified ZSM-5 zeolite
    Fuel (IF 4.601) Pub Date : 2018-01-12
    Changzhu Li, Jiangshan Ma, Zhihong Xiao, Stanton B. Hector, Rukuan Liu, Shuangmiao Zuo, Xinfeng Xie, Aihua Zhang, Hong Wu, Qiang Liu

    Catalytic cracking of Swida wilsoniana oil over non-catalyst and various Cu-modified ZSM-5 catalysts doped with different concentration of Cu (0, 5, 10, 20 and 30 wt%) was studied. The physicochemical properties of the prepared catalysts were investigated by X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) model, Transmission electron microscopy (TEM) and temperature-programmed desorption of ammonia (NH3-TPD) analysis. Results showed that the introduction of Cu did not change the crystalline structure of ZSM-5 and CuO might deposit on the surface or inside the pores. The numbers of ZSM-5 total acidic sites were increased after it was loaded with 5 wt% and 10 wt% concentration of Cu. The overall hydrocarbon biofuels yields obtained from Cu-modified ZSM-5 catalysts were improved relative to parent ZSM-5. Determination of composition of the hydrocarbon biofuels showed that the hydrocarbon fractions were the main components produced. The optimum Cu concentration used for ZSM-5 modification was 10 wt%, which obtained the highest hydrocarbon biofuels yield (68.20 wt%) and percentage of hydrocarbon fractions content (89.07 wt%). The reuse of Cu-modified ZSM-5 catalysts results showed acceptable levels of reusability after three times regeneration. In addition, the physical properties of the Cu-modified ZSM-5 catalysts produced hydrocarbon biofuels were improved compared to non-catalytic cracking of S. wilsoniana oil. This work showed that the newly developed 10 wt% concentration Cu-modified ZSM-5 was an efficient catalyst for cracking of S. wilsoniana oil for the production of hydrocarbon biofuels.

    更新日期:2018-01-17
  • Determination of the absolute adsorption/desorption isotherms of CH4 and n-C4H10 on shale from a nano-scale perspective
    Fuel (IF 4.601) Pub Date : 2018-01-12
    Yueliang Liu, Huazhou Andy Li, Yuanyuan Tian, Zhehui Jin, Hucheng Deng

    Accurate description of absolute adsorption/desorption behavior for hydrocarbons on shale is of critical importance to the understanding of the fundamental mechanisms governing the storage, transport, and recovery of shale gas or shale gas condensate in shale reservoirs. By applying a thermogravimetric method, we first measure the excess adsorption/desorption isotherms of pure CH4 and n-C4H10 on shale samples over the temperature range of 303.15–393.15 K. The maximum test pressures considered for CH4 and n-C4H10 are 50 bar and 2 bar, respectively. Grand Canonical Monte Carlo (GCMC) simulations are then applied to calculate the density of the adsorption phase by considering the fluid-pore surface interactions. We use such calculated density of the adsorption phase to calibrate the excess adsorption/desorption isotherms, which enables us to eventually obtain the absolute adsorption/desorption isotherms. Such approach for estimating the density of the adsorption phase is essentially different from the commonly used approaches in which the density of the adsorption phase is considered to be independent of temperature, pressure, and pore size. The adsorption/desorption test results show that both CH4 and n-C4H10 exhibit more adsorption as temperature decreases or pressure increases. Their adsorption/desorption isotherms exhibit hysteresis phenomenon and this phenomenon weakens as temperature increases. Comparatively, the hysteresis behavior observed for n-C4H10 is more obvious than that for CH4. Compared with CH4, n-C4H10 has higher adsorption capacity under the same condition, indicating its higher affinity towards the shale with organic matters. As for the conventional approaches, the density calculated from the van der Waals constant b or the liquid hydrocarbon density can be used to reasonably well evaluate the absolute adsorption isotherms of n-C4H10 on shale, but tends to underestimate the absolute adsorption of CH4 on shale. GCMC simulations show that the density of the adsorption phase is strongly correlated with system pressure, temperature, and pore size. Compared to the conventional approaches, GCMC simulations can better capture the in-situ density of adsorption phase; on the basis of the in-situ density of adsorption phase, we can then achieve more accurate determination of the absolute adsorption isotherms of a given hydrocarbon on shale. This study raises the imperativeness of leveraging more sophisticated simulation tools (such as GCMC) for more accurate determination of absolute adsorption isotherms.

    更新日期:2018-01-17
  • Catalytic upgrading of pyrolysis vapors from lignite over mono/bimetal-loaded mesoporous HZSM-5
    Fuel (IF 4.601) Pub Date : 2018-01-12
    Xue-Yu Ren, Jing-Pei Cao, Xiao-Yan Zhao, Zhen Yang, Tian-Long Liu, Xing Fan, Yun-Peng Zhao, Xian-Yong Wei

    HZSM-5 was modified via alkaline treatment and wet impregnation method which loading transition metals (Co, Mo–Co and Ni–Co). The performance of catalysts for the catalytic fast pyrolysis of lignite was tested in a drop tube reactor at 600 °C. In comparison to non-catalytic experiment, the chemical composition of upgrading tar was obviously simplified, which mainly contains light aromatics such as benzene, toluene, ethylbenzene, xylene and naphthalene (BTEXN). The yield of BTEXN was significantly increased from 12.9 to 26.4 mg/g when Ni/Co-H-5 was used. Meanwhile, the Ni/Co-H-5 treated by NaOH solution achieved considerable deoxygenation performance (86.6%) than other ones. The addition of bimetallic Mo–Co or Ni–Co significantly enhanced the BTEXN selectivity of HZSM-5. Ni promoted H2 formation in gaseous product and caused the decrease of naphthalenes yield. Whereas the yields of toluene and o-xylene increased after the pyrolysis vapors pass through Mo/Co-H-5. The zeolite treated by NaOH solution (AT-HZSM-5) favors the generation of aromatics and phenolics, conversely naphthalene derivatives. Moreover, AT-Mo/Co-H-5 and AT-Ni/Co-H-5 inhibited the coke formation. A catalytic pathway was also proposed to describe the diffusion process of pyrolysis vapors on the active site of catalyst.

    更新日期:2018-01-17
  • Conversion of petroleum emulsion into light fraction-rich upgraded oil in supercritical methanol
    Fuel (IF 4.601) Pub Date : 2018-01-12
    Muhammad Kashif Khan, Winarto Kwek, Jaehoon Kim
    更新日期:2018-01-17
  • Computational optimization of the combustion system of a heavy duty direct injection diesel engine operating with dimethyl-ether
    Fuel (IF 4.601) Pub Date : 2018-01-16
    Jesús Benajes, Ricardo Novella, Jose Manuel Pastor, Alberto Hernández-López, Sage L. Kokjohn

    A genetic algorithm optimization methodology is applied to the design of the combustion system of a heavy-duty diesel engine fueled with dimethyl ether (DME). The optimization includes the key combustion system related hardware, bowl geometry and injection nozzle design, together with the most relevant air management and injection settings. The GA was linked to the KIVA computational fluid dynamics code and an automated grid generation tool to perform a single-objective optimization. The optimization target focused on maximizing efficiency, while keeping NOx emissions, peak pressure and maximum pressure rise rate under the baseline engine levels. This research work not only provides the optimum combustion system definition, but also the cause-effect relation between the inputs and outputs under investigation, identifying the most relevant parameters controlling the performance of a DME fueled engine. Piston bowl geometry is found to primarily influence heat transfer and combustion efficiency due to its impact on the surface area and fuel distribution, respectively. Mixing is most affected by the injection system parameters. Finally, the optimum DME engine configuration provides 6.9% absolute net indicated efficiency improvement over the baseline engine fueled with DME. This study confirms the potential of DME as a promising fuel for the future generation of compression ignition engines and demonstrates the need to co-optimize the fuel and combustion system.

    更新日期:2018-01-17
  • Mercury release and fraction transformation during desulfurization gypsum aging process (UV irradiation)
    Fuel (IF 4.601) Pub Date : 2018-01-06
    Xing Diao, Chun-Gang Yuan, Jingjing Wu, Bing Gui, Kegang Zhang, Cheng Zhang

    The transformation of mercury fractions under both natural environmental conditions and ultraviolet irradiation (UV) conditions was studied in this work. Mercury in desulfurization gypsum was divided into five fractions by sequential extraction procedure depending on its bioavailability. The five fractions were named as water soluble fraction (F1), ion-exchangeable fraction (F2), acid soluble fraction (F3), elemental fraction (F4), and sulfide fraction (F5). The results from our study demonstrated that the proportion of different fraction was in the following order: elemental fraction > water soluble fraction > acid soluble fraction > ion-exchangeable fraction > sulfide fraction. The results indicated that mercury could be released from desulfurization gypsum during aging process and the release process could be promoted via ultraviolet irradiation. The release amount increased with the irradiation time and intensity (up to 25.1% of the total initial amount). The percentage of mercury in F1 decreased gradually with aging time, while the percentage of mercury in elemental and residual fractions increased gradually. Our research will be helpful for the survey and understand of mercury emission from desulfurization gypsum.

    更新日期:2018-01-10
  • In-situ CO2 generation for EOR by using urea as a gas generation agent
    Fuel (IF 4.601) Pub Date : 2018-01-05
    Shuoshi Wang, Changlong Chen, Benjamin Shiau, Jeffrey H. Harwell

    While injection of CO2 has great potential for increasing oil production, this potential is limited by site conditions and operational constraints such as lack of proper infrastructure, limited cheap CO2 sources, viscous fingering, gravity override at the targeted zones, and so forth. To mitigate some of these common limitations, we explore alternative methodologies which can successfully deliver CO2 through gas generation in situ, with superior IOR performance, while offering reasonable chemical cost. A new approach of in situ CO2 generation EOR was proved through a series of high-pressure and high-temperature laboratory scale experiments in this work. Urea was selected as a potential source of generating CO2 in situ because of its remarkable availability at bulk quantity and resistance to divalent cations. Urea is highly soluble in fresh water or brine and can decompose at reservoir conditions spontaneously to release carbon dioxide and ammonia. The tertiary oil recovery performance of the urea solution was evaluated in sand pack flooding at different operational conditions. We studied the flow rate ranging from 13.6 in./day to 36.2 in./day, the urea concentration ranging from 5% to 35%, the pressure ranging from 1500 psi to 4000 psi and the oil API ranging from 27 to 57.3, either with or without the presence of divalent ions. Recovered oil compositional analyses also revealed the additional benefits from the produced ammonia in tertiary recovery. Most importantly, results of injecting urea solution (as low as 5% solution) showed superior tertiary recovery performance (as high as 37.5%) as compared to the most recent efforts at our group (29.5%) as well as similar in situ CO2 generation EOR (2.4%–18.8%) approaches proposed by others. Because of the remarkable reservoir brine compatibility of urea, even under seawater levels of divalent ions, the floods showed no detectible effect of brine composition on the recovery and/or any occurrence of formation damage. Furthermore, the preferable wettability reversal was indicated by recovered oil compositional analyses. The economic feasibility and advantages of the newly proposed technique were demonstrated. The results served as a proof of concept for in situ CO2 generation tertiary oil recovery potential for both onshore and offshore fields.

    更新日期:2018-01-06
  • Effect of producer gas addition and air excess ratio on natural gas flame luminescence
    Fuel (IF 4.601) Pub Date : 2018-01-05
    Robertas Navakas, Andrius Saliamonas, Nerijus Striūgas, Algis Džiugys, Rolandas Paulauskas, Kęstutis Zakarauskas

    This paper presents the emission spectroscopy method for registering chemiluminescent radical species of View the MathML source OH ∗ , CH ∗ , C 2 ∗ by means of optical flame imaging using optical bandpass filters, corresponding to emission wavelengths of the radicals of interest, and by scanning the flame using optical fibers coupled to a spectrometer for recording the emission spectra. The aim of this research is to analyse the distribution of chemiluminescence intensity along the flame axis from various angles simultaneously in order to determine the effect of the air equivalence ratio (ER) and mixing of producer gas (PG) from biomass gasification into the natural gas flow to spectral characteristics of flame at specific wavelengths representing formation reactions of OH∗ OH ∗ radical species. The experiments were carried out with pure natural gas (NG) and air mixture and a premixed air/gas mixtures (80%NG and 20% PG, 65%NG and 35%PG). Flows of air, NG and PG were premixed before entering the combustion chamber. For flame emission spectroscopy, two different methods were used: 1) imaging by an ICCD camera through optical bandpass filters suitable for View the MathML source OH ∗ , CH ∗ , C 2 ∗ chemiluminescence intensity registration; 2) by a combination of a spectrometer and five optical fibers to collect the flame spectra from 5 different angles and in various heights from the burner outlet. The distribution of chemiluminescent species intensity along the burner vertical axis was analyzed and zones with most intense View the MathML source OH ∗ , CH ∗ , C 2 ∗ generation in flame were identified, and the effect of addition of PG to NG and ER to the OH∗ OH ∗ chemiluminescence was analysed.

    更新日期:2018-01-06
  • Inhibiting effect of imidazolium-based ionic liquids on the spontaneous combustion characteristics of lignite
    Fuel (IF 4.601) Pub Date : 2018-01-05
    Fu-Sheng Cui, Bin Laiwang, Chi-Min Shu, Jun-Cheng Jiang

    In this study, three imidazolium-based ionic liquids (ILs) and distilled water flushing were used to treat lignite subsamples to ascertain the inhibiting effect of ILs on the spontaneous combustion characteristics of lignite. The combustion characteristics, gas generation results during decomposition, and changes in the functional groups in these IL- and water-treated coal subsamples were compared with those of untreated coal through thermogravimetry and Fourier transform infrared spectroscopy analysis. The results showed that 1,3-dimethylimidazolium iodide ([Mmim][I]) was the most capable of reducing the −OH groups in lignite and inhibiting the spontaneous combustion of lignite. Furthermore, 1-ethyl-3-methylimidazolium iodide ([Emim][I]) was the most capable of increasing the −COOH groups in lignite and reducing the maximum mass loss rate of lignite. Analysis of the recovered ILs revealed that the ILs did not substantially change after the treatment, and recovery rates higher than 92% were achieved.

    更新日期:2018-01-06
  • Effect of atmosphere on carbon deposition of Ni/Al2O3 and Ni-loaded on lignite char during reforming of toluene as a biomass tar model compound
    Fuel (IF 4.601) Pub Date : 2018-01-05
    Jing-Pei Cao, Jie Ren, Xiao-Yan Zhao, Xian-Yong Wei, Takayuki Takarada
    更新日期:2018-01-06
  • 更新日期:2018-01-05
  • Properties of biochar
    Fuel (IF 4.601) Pub Date : 2018-01-02
    Kathrin Weber, Peter Quicker

    Biochar can be used in a large number of applications, ranging from heat and power production to soil amendment. The properties of carbonized biomass depend on the feedstock and the process conditions. Selection of suitable conditions to produce a char with the desired properties therefore requires knowledge of dependencies and influencing factors, both quantitatively and qualitatively. This paper reviews and summarizes the results from a large number of experiments on biochar production in order to give a general overview of the properties that can be achieved by feedstock selection and process design. Production processes include both torrefaction as well as slow pyrolysis at high temperatures. The data evaluation has shown that among all process conditions, the treatment temperature has by far the most dominant influence on all properties. Especially the rather narrow temperature range between 200 and 400 °C causes the most significant changes and is therefore very sensible to influences and possibly difficult to control.

    更新日期:2018-01-04
  • Conversion of low-grade coals in sub-and supercritical water: A review
    Fuel (IF 4.601) Pub Date : 2018-01-02
    Jiangdong Yu, Chunyan Jiang, Qingqing Guan, Junjie Gu, Ping Ning, Rongrong Miao, Qiuling Chen, Junmin Zhang

    Low-rank coals are very abundant in several regions throughout the world. However, it is difficult to use the low-rank coals directly due to their undesirable characteristics such as high moisture, high ash and high oxygen content. The utilization of low-rank coals has received more and more attention with the increase of consumption of other fossil fuels. Besides the pyrolysis and alcoholysis, the conversion of low-lank coals under hydrothermal conditions (including sub-and supercritical water) for high-quality solid fuel, coal liquefied oil and gaseous fuels has also been widely investigated. In this review, the development of low-rank coal hydrothermal upgrading, the liquid fuel production from coal in sub-and supercritical water and supercritical water gasification of coal for hydrogen production, including partial oxidative gasification, homogeneous/heterogeneous catalytic gasification and related kinetic investigations are discussed. In addition, the element transformation such as N, S and metals during the hydrothermal process are also presented.

    更新日期:2018-01-04
  • Porous catalysts fabricated from coal fly ash as cost-effective alternatives for industrial applications: A review
    Fuel (IF 4.601) Pub Date : 2018-01-02
    Seyed Mostafa Hosseini Asl, Arezou Ghadi, Mazyar Sharifzadeh Baei, Hamedreza Javadian, Mehdi Maghsudi, Hossein Kazemian

    Coal fly ash (CFA) -an industrial solid waste- has tremendous potential to be used as a starting material for development of valuable porous catalysts and adsorbents because of its silicon and aluminum content. Among various products fabricated from CFA by chemical synthesis process, CFA-based porous catalysts have recently gained remarkable interest among researchers. Each CFA–based catalyst has different properties, the most important of which is the ion exchange capability that depends on the chemical composition and structure of the synthesized product. Studies proved that CFA-based compounds can be used as catalysts/photocatalysts in different environmental processes such as degradation of pollutants. Chemical conversion reactions and synthesis of fine chemicals are among other applications, in which CFA is used as substrate for developing different catalysts. In this review paper, CFA-based catalysts have been classified based on their properties and applications. Methods of characterizations including kinetics and isotherm models are discussed. Furthermore, the effect of several parameters including reaction time, reaction temperature, and the ratio of active compounds to CFA substrate on chemical reactions catalyzed by CFA-based catalysts are discussed. This review paper reveals that CFA-based catalysts are highly efficient compounds not only for application in environmental pollution remediation processes, but also in achieving comparable results in chemical conversion reactions for synthesizing fine chemicals. It can be concluded that CFA as a solid waste should be considered as a low-cost source of alumino-silicate that is a promising candidate for developing inexpensive methods of manufacturing highly efficient and eco-friendly porous catalysts for a wide array of applications.

    更新日期:2018-01-04
  • Synthesis of diesel additives from fructose over PWA/SBA-15 catalyst
    Fuel (IF 4.601) Pub Date : 2018-01-02
    Chetana R. Patil, Chandrashekhar V. Rode

    A series of composites of phosphotungstic acid (PWA) H3PW12O40 with SBA-15 were prepared by varying PWA amount from 5% to 30% by one-step sol-gel hydrothermal as well as by impregnation methods. Successful incorporation of PWA into the SBA-15 framework by sol-gel method was confirmed by 31P NMR in which a shifting of the peak due to tetrahedral ‘P’ atom of PWA from −14.32 and −14.49 ppm was observed. The composites exhibited both Brønsted and Lewis acidity, large and well distributed three dimensional interconnected pores with high surface areas exhibiting excellent activity for one pot synthesis of 5-(hydroxymethyl) furfural (5-HMF) and 5-(ethoxymethyl) furfural (EMF) from fructose. The minimum loading of 5% of PWA in SBA-15, gave 78% fructose conversion with the highest yield of 70% towards 5-HMF. Increase in PWA loading up to 20% resulted in the enhanced fructose conversion of 95% accompanied by further etherification of 5-HMF to 67 and 12% yield towards EMF and ethyl levulinate (EL), respectively. Increasing the % of PWA in SBA-15 matrix resulted in increase in the acidity of the composites giving the yield trend as 5-HMF < EMF < EL. Catalyst prepared by sol-gel method showed excellent recyclability up to 3 reuses.

    更新日期:2018-01-04
  • Methane partial oxidation in a two-layer porous media burner with Al2O3 pellets of different diameters
    Fuel (IF 4.601) Pub Date : 2018-01-02
    Yuqing Wang, Hongyu Zeng, Yixiang Shi, Ningsheng Cai

    In this study, the fuel-rich combustion of methane in a two-layer porous media burner with Al2O3 pellets of different diameters was experimentally investigated. The upstream layer consisted of 2.5-mm diameter packed Al2O3 pellets, and the downstream layer consisted of 5-mm, 6.5-mm, 7.5-mm, and 9.5-mm diameter packed Al2O3 pellets. The effects of pellet diameter on the temperature distribution, exhaust composition, and the syngas energy conversion efficiencies were studied at a fixed operation condition with an equivalence ratio of 1.6 and a gas velocity of 0.13 m/s. An optimal downstream pellet diameter of 7.5 mm was determined for the partial oxidation of methane corresponding to the highest syngas energy conversion efficiency. Stabilized methane fuel-rich flames were realized in the optimized burner for various gas velocities (0.09 m/s–0.15 m/s) and equivalence ratios (1.2–1.7). The effects of operation conditions (gas velocities and equivalence ratios) on the combustion performance were also tested. We found that 50.0% of the methane was converted to H2 and CO at an equivalence ratio of 1.7 and an inlet gas velocity of 0.15 m/s with burner energy conversion efficiency based on lower heating values.

    更新日期:2018-01-04
  • Numerical investigation of different effects of carbon dioxide properties and carbon monoxide oxidation on char particle combustion in actual and fictitious O2/CO2 environments
    Fuel (IF 4.601) Pub Date : 2018-01-02
    Xudong Jin, Yuegui Zhou, Shankai Zheng

    The overall and individual effects of carbon dioxide properties and carbon monoxide oxidation on char combustion were numerically simulated with a continuous-film model in different O2/CO2, O2/N2 and O2/Ar environments, and different CO2 physicochemical properties were artificially changed to distinguish the individual effect on char particle temperature and combustion rate. The results show that the char combustion rate in 21%O2/79%CO2 environment is slightly higher than that in air environment because of two opposite effects of higher char gasification reaction rate with high concentration CO2 and lower char oxidation rate with O2 resulting from lower particle temperature. At the same time, the CO flame front in 21%O2/79%CO2 environment is farther away from char particle surface than that in 21%O2/79%N2 environment because of lower diffusion coefficient of oxygen in CO2 environment although the gas temperature is lower. Furthermore, the net effect of molar heat capacity of CO2 on char combustion rate decreases and the net effect of char gasification reaction with CO2 on char combustion rate distinctly increases with the increase of ambient gas temperature and O2 mole concentration.

    更新日期:2018-01-04
  • Performance and emissions of diesel-gasoline-ethanol blends in a light duty compression ignition engine
    Fuel (IF 4.601) Pub Date : 2018-01-02
    Giacomo Belgiorno, Gabriele Di Blasio, Sam Shamun, Carlo Beatrice, Per Tunestål, Martin Tunér

    An approach to reduce CO2 emissions while simultaneously keeping the soot emissions down from compression ignition (CI) engines is to blend in short chained oxygenates into the fuel. In this work, two oxygenated fuel blends consisting of diesel, gasoline and ethanol (EtOH) in the ratio of 68:17:15 and 58:14:30 have been utilized and studied in a single cylinder light duty (LD) CI engine in terms of efficiency and emissions. The reasons of utilizing gasoline in the fuel blend is due to the emulsifying properties it has while increasing the total octane rating of the fuel to be able to run the engine with a higher fraction of premixed flame. When performing the experiments, the control parameters were set as close as possible to the original equipment manufacturer (OEM) EU5 calibration of the multi-cylinder engine to study the possibility of using such blends in close to stock LD CI engines. With the oxygenates, in particular the fuel with the higher concentration of EtOH achieved an indicated net efficiency of ∼ ∼ 51% inf comparison to ∼ ∼ 47% for diesel at 8 bar BMEP. The NOX emissions increased slightly for the double injection strategy at 13 bar BMEP from ∼ ∼ 13.5 g/kW h to ∼ ∼ 14.5 g/kW h when going from diesel fuel to the higher ethanol blend. However utilizing single injection strategy at lower loads reduces the NOX. Highest soot mass measured for diesel was ∼ ∼ 0.46 g/kW h in contrast to ∼ ∼ 0.1 g/kW h for the oxygenates. Also, soot production when running the engine on the ethanol containing fuels was not significantly affected by EGR utilization as in the case of diesel. Considering particle size distribution, the particles are reduced both in terms of mean diameter and quantity. At 1500 rpm and 2 bar BMEP an increase of over ∼ ∼ 300% in THC and CO was measured, however, increasing the speed and load to above 2000 rpm and 8 bar BMEP respectively, made the difference negligible due to high in-cylinder temperatures contributing to better fuel oxidation. Despite having lower cetane numbers, higher combustion stability was observed for the oxygenates fuels.

    更新日期:2018-01-04
  • Anaerobic biodegradability test of water hyacinth after microbial pretreatment to optimise the ideal F/M ratio
    Fuel (IF 4.601) Pub Date : 2018-01-02
    Visva Bharati Barua, Ajay S. Kalamdhad

    Water hyacinth is a deadly weed in an aquatic environment but a potential feedstock for the generation of renewable biogas through anaerobic digestion. Biochemical methane potential (BMP) was examined for fresh water hyacinth whole plant after microbial pretreatment to determine the ideal food to microorganism (F/M) ratio. The study revealed that after microbial pretreatment of water hyacinth the F/M ratio 1.5 showed the highest methane yield of 156 ± 19 mL CH4/g VS on the 20th day. It was observed that the microbial pretreated water hyacinth illustrated enhanced biogas production within a short time period when compared to the untreated water hyacinth. The ideal F/M ratio played a significant role alongwith the microbial pretreatment process to accelerate the hydrolysis period and increasing biogas generation.

    更新日期:2018-01-04
  • Large volume in situ H2 production on fixed bed reactor by concentrated formic acid aqueous solution
    Fuel (IF 4.601) Pub Date : 2018-01-02
    Yaqiu Tao, Lulu Tao, Zhigang Pan, Simin Qiu, Xiaodong Shen
    更新日期:2018-01-04
  • Characteristics of methane desorption and diffusion in coal within a negative pressure environment
    Fuel (IF 4.601) Pub Date : 2018-01-02
    Yunfei Du, Xiangjun Chen, Liyang Li, Peng Wang

    To study the characteristics of gas diffusion and changes in the dynamic parameters of coal under a negative pressure environment, experiments were performed to constrain the desorption process under different negative pressures in coal samples at (0.5, 1.5 and 2.5) MPa adsorption equilibrium pressures. The experimental results demonstrate that the relation curves between time and the desorption quantities of coal samples with different negative pressures have shapes similar to that of Langmuir’s adsorption isotherm. In addition, all coal samples with different negative pressures have a maximum regarding methane desorption. As the negative pressure increases from 10 kPa to 40 kPa, the limitation gas desorption amount increases from 8.73 to 10.93 mL/g, from 14.91 to 17.75 mL/g, and from 18.30 to 23.27 mL/g, respectively, under 0.5 MPa, 1.5 Mpa and 2.5 Mpa adsorption equilibrium pressure. Moreover, under the same adsorption pressure, the larger the negative pressure becomes, the greater the gas desorption velocity of the first minute (V1) is. The change of gas desorption velocity with negative pressure during the first minute is an exponential function. The performance under different adsorption equilibrium pressures demonstrates the same regularity. With the increase of negative pressure, interfacial mass transfer resistance also decreases, and the diffusion coefficient and Fourier’s criterion of mass transmission increase. This indicates that the negative pressure environment changes the desorption kinetic-parameters of the coal mass and increases the amounts of methane desorption and desorption velocity, which are advantageous for desorption and diffusion of coal methane.

    更新日期:2018-01-04
  • 更新日期:2018-01-04
  • Development of a particle swarm optimisation model for estimating the homogeneity of a mixture inside a newly designed CNG-H2-AIR mixer for a dual fuel engine: An experimental and theoretic study
    Fuel (IF 4.601) Pub Date : 2018-01-02
    Hussein A. Mahmood, Nor Mariah. Adam, B.B. Sahari, S.U. Masuri

    Many research works have intended to enhance fuel economy and decrease emissions during conversion from a diesel engine to a dual fuel engine. However, the majority of these works do not take into account enhancement of homogeneity of the mixture inside the engine and precise control of the air fuel ratio. This deficiency can cause higher emissions, greater brake-specific fuel consumption, and likely knocking. Conversely, there is limited research pertaining to empirical equations for projecting the mixture’s homogeneity. In this study, a new air–fuel mixer was devised, produced and tested. For the air-gaseous fuel mixer, the proposed design was meant to be appropriate for mixing air with hydrogen and CNG. It was also designed in such a way that it would result into extremely homogeneous mixing for the gaseous fuel as it mixes with air and exhibits high uniformity index (UI). Lastly, it is also meant to promote easy connection with an electronic control unit so that the air-gaseous fuel ratio could be accurately controlled for varying engine speeds. To optimise the homogeneity within the new mixer, fifteen varying mixer models having 116 cases were made in order to study how the location, diameter, and number of holes within the mixer affect the mixture’s homogeneity and distribution under ACNGR = 34.15 and AHR = 74.76. Afterwards, the distribution, flow behaviour, and homogeneity of the mixture within the new mixer models were checked using computational fluid dynamics analysis software. Based on the simulation results, it was discovered that the best uniformity index (UI) values were achieved for models 7/ case 48. Based on the simulation results, a fairly simple method was then developed to estimate the mixture’s homogeneity (UI) from the new models of the mixer. The basis of the proposal model (empirical equation) is from the best values determined for the unknown constant F so that the equation for UI estimation could be formulated. The particle swarm optimisation (PSO) algorithm was used to solve an optimisation problem and achieve this outcome. The outcomes indicated that the built model could precisely project the UI values.

    更新日期:2018-01-04
  • A study on three-phase CO2 methanation reaction kinetics in a continuous stirred-tank slurry reactor
    Fuel (IF 4.601) Pub Date : 2018-01-02
    Jonathan Lefebvre, Nike Trudel, Siegfried Bajohr, Thomas Kolb

    The reaction kinetics of the three-phase CO2 methanation for a commercial Ni/SiO2 catalyst suspended in a liquid phase is studied in a continuous stirred-tank slurry reactor at a CO2 partial pressure of 1 bar and temperatures from 220 °C to 320 °C. By applying different liquids, namely squalane, octadecane, and dibenzyltoluene, showing different gas solubilities, it is found that the gas concentration in the liquid phase and not the partial pressure in the gas phase is the driving force for the CO2 methanation reaction kinetics. The liquid phase does not influence the reaction kinetics but reduces the available gas concentrations and H2/CO2 ratio on the catalyst surface. Based on these findings, a kinetic rate equation for the three-phase CO2 methanation is developed additionally incorporating the chemical equilibrium limitations relevant in the temperature regime.

    更新日期:2018-01-04
  • Burning velocities of dimethyl ether (DME)–nitrous oxide (N2O) mixtures
    Fuel (IF 4.601) Pub Date : 2018-01-02
    Yohji Yamamoto, Takeshi Tachibana

    From a usability and capability perspective, dimethyl ether (DME) fuel with nitrous oxide (N2O) as oxidant is a promising combination for next-generation combustion devices or propellants for space vehicles. However, to ensure proper and profitable application of this fuel, we must clarify the combustion characteristics of the DME–N2O mixture. To this end, we conducted burning velocity experiments using the closed spherical bomb technique initiated at 0.1 MPa and 295 K and ran numerical models considering the DME oxidation and N2O decomposition reaction mechanisms in the DME–N2O mixtures. To characterize the N2O oxidant, we compared the experimental and theoretical results of DME–N2O with those of air and N2/0.5O2 gases as oxidants. Among the three mixtures (containing the same amount of DME 6.54% by volumetric fraction), DME–N2O exhibited the lowest burning velocity, although N2O has large heat of formation. The experimental burning velocity of DME–N2O was slowed by the low thermal diffusivity and the delay caused by the decomposition reactions of N2O, N2O (+M) ↔ N2 + O (+M), N2O + H ↔ N2 + OH, and N2O + H ↔ NH + NO, which are same as those that are considered important in the oxidation of C1–C3 hydrocarbon–N2O mixtures.

    更新日期:2018-01-04
  • La-based catalysts to enhance hydrogen production during supercritical water gasification of glucose
    Fuel (IF 4.601) Pub Date : 2018-01-02
    Muhammad B.I. Chowdhury, Md. Zakir Hossain, Jahirul Mazumder, Anil K. Jhawar, Paul A. Charpentier

    Controlling hydrogen production during supercritical water gasification (SCWG) of biomass is challenging using conventional mono-metallic catalysts. This work examines the role of Lanthanum (La) both as a catalyst and co-catalyst with Nickel (Ni), for enhancing the Water-Gas Shift (WGS) reaction to maximize hydrogen production. A stirred tank batch reactor was used with glucose as feed (model compound for biomass), from T = 400 to 500 °C, residence time = 5–120 min and P = 28 MPa. Compared to non-catalytic gasification, the La2O3/Al2O3 catalyst enhanced both the H2 and CO2 production by 1.9-fold and 2.0-fold respectively. Ni-La2O3/Al2O3 catalyst increased hydrogen production (3.95 mol/mol feed) to almost thermodynamic equilibrium composition (4.15 mol/mol feed) at 120 min reaction time. By examining the fresh and spent catalysts by various physico-chemical techniques, this enhancement is attributed to the Ni promoting tar cracking, while La promoted the WGS reaction and inhibits the methanation reactions. A parametric study was used to optimize reaction conditions, finding that H2 production and carbon conversion to gaseous products increased significantly with higher reaction time and temperatures and lower feed concentrations. Almost 98% carbon was gasified at 120 min reaction time using Ni-La2O3/Al2O3 as catalyst. Using a controlled feedstock of CO and H2 to further examine the catalytic mechanism, adding La onto the Ni/Al2O3 enhanced CO2 and H2 production with negligible CH4 production, showing the importance of the WGS reaction to maximizing H2 production in SCWG.

    更新日期:2018-01-04
  • Effect of degree of triglyceride unsaturation on aromatics content in bio-oil
    Fuel (IF 4.601) Pub Date : 2018-01-02
    R.F. Beims, V. Botton, L. Ender, D.R. Scharf, E.L. Simionatto, H.F. Meier, V.R. Wiggers

    In this study, the influence of the degree of unsaturation of the triglyceride on the composition of the products of the thermal cracking process, in particular the formation of aromatic compounds, was investigated. Experiments were performed using triglyceride sources with different degrees of unsaturation, maintaining the same operational conditions. Analysis of the products revealed that a greater amount of aromatic compounds is formed during the thermal cracking of biomass with a higher degree of unsaturation. The aromatics content in the liquid product decreased by 14% in the cracking of biomass with the lowest unsaturated content. A correlation between the aromatics content and the iodine index of the sample was proposed, as a simple way to estimate the aromatics content in bio-oil. It was also observed that the reactions for carboxyl removal were favorable in the case of saturated compounds, the acidity index reducing from 210.9 to 139.0 gKOH/g in the biomass with the lowest unsaturated content. However, long-chain paraffinic compounds were present in the products, which suggests that a catalyst or more severe conditions might be necessary for the biomass cracking.

    更新日期:2018-01-04
  • Molecular dynamics simulation of the high-temperature pyrolysis of methylcyclohexane
    Fuel (IF 4.601) Pub Date : 2018-01-02
    Yalan Liu, Junxia Ding, Ke-Li Han

    To better understand the initiation and intermediate reaction mechanisms associated with the high-temperature pyrolysis of methylcyclohexane (MCH), the dissociation of MCH is investigated using reactive molecular dynamics (RMD) and density functional theory (DFT) calculations. It is observed that the pyrolysis of MCH is initiated by four types of reaction channels. The initiation of the decomposition is mainly through the C single bond C bond homolysis of the six-membered ring, leading to ring opening and the formation of C7H14 diradicals. Subsequently, the biradicals undergo successive decomposition by the β-scission of the C single bond C bonds to form ethylene. Furthermore, to provide a detailed description of the pyrolysis behavior of MCH, the distributions of key products, intermediate reactions and corresponding kinetic behavior are systematically analyzed at the atomic level. The apparent activation energy extracted from the RMD simulations is 263.60 kJ/mol at temperatures from 2300 K to 3100 K, which is reasonably consistent with the experimental results.

    更新日期:2018-01-04
  • Understanding the relationship between the structure and depolymerization behavior of lignin
    Fuel (IF 4.601) Pub Date : 2018-01-02
    Jaeyong Park, Asim Riaz, Rizki Insyani, Jaehoon Kim
    更新日期:2018-01-04
  • Influences of water vapor and fly ash on elemental mercury removal over cerium-oxide-modified semi-coke
    Fuel (IF 4.601) Pub Date : 2018-01-02
    Huawei Zhang, Huamin Sun, Ke Zhao, Ye Han, Jiafeng Wu, Tiantian Jiao, Peng Liang

    A bench-scale fixed bed reactor was used to study the influences of water vapor and fly ash on Hg0 removal efficiency over CeO2-modified semi-coke adsorbent (Ce/SC). Adsorption results showed that the mercury removal efficiency of Ce/SC decreased by 30% in the presence of 10% water vapor, and the introduction of 0.5 g fly ash had no significant effect on the Hg0 removal efficiency of Ce/SC. In the condition of water vapor and fly ash coexisted, the Hg0 removal efficiency of Ce/SC decreased by only 15%, indicated that the fly ash slowed down the inhibitory effects of water vapor on Hg0 removal efficiency over Ce/SC, which is mainly due to the interaction between water vapor and Fe2O3 in the fly ash to form Fe-OH groups, furthermore, γ-Fe2O3 exhibited higher Hg0 removal performance than α-Fe2O3. Hydrogen temperature-programmed reduction (H2-TPR) revealed that the oxidation activity and capacity of α-Fe2O3 and γ-Fe2O3 increased significantly after water vapor treatment. X-ray photoelectron spectroscopy (XPS) results showed that the Fe-OH content of α-Fe2O3 and γ-Fe2O3 increased from 37.97% and 15.99% to 44.56% and 43.39%, while the lattice oxygen content decreased from 26.53% and 82.46% to 19.08% and 46.49%, respectively. Density functional theory (DFT) calculations revealed that H2O molecules can be dissociated on both α-Fe2O3 (1 0 4) and γ-Fe2O3 (2 2 0) surfaces to form H atoms and OH fragments, the H atoms bound with O atoms in Fe-O groups of both α-Fe2O3 (1 0 4) and γ-Fe2O3 (2 2 0) surfaces, and the OH fragments associated with the adjacent iron atoms of α-Fe2O3 (1 0 4) surface or Fe-O groups of γ-Fe2O3 (2 2 0) surface to form Fe-OH. The formation of Fe-OH groups increased the oxidation activity and Hg0 removal efficiency of Fe2O3.

    更新日期:2018-01-04
  • Nanoscale and multiresolution models for shale samples
    Fuel (IF 4.601) Pub Date : 2018-01-02
    Pejman Tahmasebi

    Characterization of shale systems requires imaging at different scales. One reason can be due to a diverse pore-size distribution. Low-resolution images often cover the large-scale structures and are available for a large region of the sample. On the other hand, fine-scale images usually cover a small region and they are mostly used to discover the complexity within the nano-scale pores in shale samples. Acquiring large image containing both the micro- and the nano-scale feature can be very expensive and time demanding. In this paper, a new method for integrating of such images at different scales is proposed. The aim is to include the nano-scale information within the coarse images. The input of this method is a set of coarse- and fine-scale images. The corresponding regions of each fine-scale image within the coarser image are determined using a similarity map. Then, the coarse image is refined iteratively to include the fine-scale information. The final image contains both the micro and nano-meter images and can readily be used for various purposes.

    更新日期:2018-01-04
  • An updated reaction model for the high-temperature pyrolysis and oxidation of acetaldehyde
    Fuel (IF 4.601) Pub Date : 2018-01-02
    R. Mével, K. Chatelain, G. Blanquart, J.E. Shepherd

    Oxygenated biofuels such as fatty acid methyl esters or ethanol are incorporated in larger and larger amounts into conventional hydrocarbon fuels for use in internal combustion and jet engines. The use of these alternative fuels, along with new engine technology, results in an increased production of toxic pollutants among which aldehydes are the most abundant. The present study focuses on the kinetic modeling of acetaldehyde pyrolysis and oxidation. Based on new ignition delay-time measurements obtained in shock tube and the data from the literature, a comprehensive validation database was assembled. Available kinetic parameters for the most important chemical reactions are reviewed and an updated reaction model is proposed. The new reaction model enables reproducing most of the trends observed experimentally and constitutes an overall improvement as compared to standard detailed chemical models including Aramco 2.0, CaltechMech, and JetSurf.

    更新日期:2018-01-04
  • Analytical solution for steam-assisted gravity drainage with consideration of temperature variation along the edge of a steam chamber
    Fuel (IF 4.601) Pub Date : 2018-01-02
    Xiaoxing Shi, Ryosuke Okuno

    Steam-assisted gravity drainage (SAGD) is a widely-used method for heavy-oil and bitumen recovery. Analytical SAGD models presented in the literature often overestimate bitumen-production rate substantially. Although bitumen-production rate and steam-oil ratio (SOR) depend significantly on temperature near the steam-chamber edge in SAGD, previous analytical models assumed the injected-steam temperature to uniformly distribute along the edge of a steam chamber. The main objective of this research is to develop the first analytical SAGD model that takes into account temperature variation along the edge of a steam chamber. Local material balance and Darcy’s law are applied to each cross section perpendicular to the edge of a steam chamber. Then, they are coupled with the global material balance for the chamber geometry that is an inverted triangle. New analytical equations are presented for bitumen-production rate and SOR, in addition to associated variables as functions of elevation from the production well, such as oil-flow rate and temperature along a linear chamber edge. Bitumen-production rate and SOR can be calculated for a representative chamber-edge temperature at a certain elevation from the production well. Comparison of the analytical model with numerical simulations shows that bitumen-production rate and SOR can be accurately estimated when the new model is used with the temperature taken from the midpoint of the edge of a steam chamber. The chamber-edge temperature used for the new analytical model that gives accurate results can be up to 100 Kelvin lower than the injected steam temperature for a given operating pressure in the cases tested. The previous assumption of the injected-steam temperature at the chamber edge gives overestimated oil-production rates for SAGD. The constant temperature along the edge of a steam chamber gives Butler’s concave interface of a steam chamber that is detached from the production well. For a chamber to exhibit a linear interface, temperature must vary along the chamber edge, which occurs in reality mainly because of heat losses to the over- and under-burden formations.

    更新日期:2018-01-04
  • Carbonated water injection under reservoir conditions; in-situ WAG-type EOR
    Fuel (IF 4.601) Pub Date : 2018-01-02
    Pedram Mahzari, Pantelis Tsolis, Mehran Sohrabi, Sultan Enezi, Ali A. Yousef, Ahmed A. Eidan
    更新日期:2018-01-04
  • Cu-BTC as a novel material for elemental mercury removal from sintering gas
    Fuel (IF 4.601) Pub Date : 2018-01-02
    Dongyao Chen, Songjian Zhao, Zan Qu, Naiqiang Yan
    更新日期:2018-01-04
  • Entrained flow gasification Part 1: Gasification of glycol in an atmospheric-pressure experimental rig
    Fuel (IF 4.601) Pub Date : 2018-01-02
    S. Fleck, U. Santo, C. Hotz, T. Jakobs, G. Eckel, M. Mancini, R. Weber, T. Kolb

    Three coordinated papers are presented concerning entrained flow gasification of a liquid fuel under atmospheric conditions. The work is based on a detailed mapping of process parameters inside the entrained flow gasifier and at the gasifier outlet. In this paper the experimental setup and the experimental data are reported. Mono ethylene glycol (MEG) is used as a well-defined surrogate fuel for biogenic oils. The overall performance of the reactor is evaluated by measuring the gas-phase composition at the reactor outlet; radial profiles of gas-phase composition (CO2, CO, H2, CH4, hydrocarbons) and temperature at 300 and 680 mm distances from the burner are measured to describe the mixing and reaction pattern in the gasifier. Global and local species balances are used to derive data that are not accessible by measurement. Characteristic parameters, i.e. stoichiometry, carbon conversion and water gas shift temperature, are derived to assess consistency of the measured data. Droplet size distribution and droplet velocity at the burner nozzle are reported based on atomization test rig experiments and direct measurements in the burner near field under gasification conditions. The experiments show a free jet with a strong outer recirculation zone as core gasification pattern. The measured species concentrations and temperatures provide an insight into both the mixing and the reactions in the burner near field. The water gas shift equilibrium is reached for a temperature of 1495 K upstream of the gasifier outlet. Hydrocarbons are not completely converted due to the low temperatures near the gasifier outlet. The research work has been conducted within the research cooperation of the Helmholtz Virtual Institute HVIGasTech.

    更新日期:2018-01-04
  • Green synthesis of Ni supported hematite catalysts for syngas production from catalytic cracking of toluene as a model compound of biomass tar
    Fuel (IF 4.601) Pub Date : 2018-01-02
    Xuehua Zou, Zhiyuan Ma, Haibo Liu, Dong Chen, Can Wang, Ping Zhang, Tianhu Chen

    In this work, natural limonite (NL) was selected as the precursor of hematite (H) to prepare the Ni-based catalysts (Nix/H) for catalytic cracking of toluene. The influences of nickel loading and reaction temperature on catalytic cracking of toluene as well as the lifetime of catalyst were evaluated and the gas products were determined. The catalysts before and after catalytic cracking were characterized by XRD (X-ray diffraction), H2-TPR (H2 temperature-programmed reduction), TEM (Transmission electron microscopy), XPS (X-ray photoelectron spectroscopy). The results showed that the catalytic activity of Nix/H was obviously improved after the Ni addition due to the formation of Ni-Fe alloy. Toluene conversion increased at first with increasing of Ni loading from 0 to 6% and then decreased from 6 to 10%. High toluene conversion of 96% and stability were achieved as the Ni loading was 6% at the reaction temperature of 800 °C. Meanwhile, toluene was mainly decomposed into CO, H2, CH4, CO2 and hematite was transformed into magnetite due to the consumption of active lattice oxygen during the catalytic cracking reaction. However, the decrease in catalytic activity of Nix/H with the increase of reaction time should be attributed to the metal carbide type coke formation.

    更新日期:2018-01-04
  • Experimental and numerical study on bluff-body and swirl stabilized diffusion flames
    Fuel (IF 4.601) Pub Date : 2018-01-02
    Yiheng Tong, Xiao Liu, Zhenkan Wang, Mattias Richter, Jens Klingmann

    Bluff-body and swirl flow are commonly utilized to stabilize diffusion flames in industrial applications, such as gas turbines, ramjets and furnaces. Flame stabilization mechanisms of these two kinds of burners are similar with each other: the interaction between the recirculation zone and the fuel jet. In the present paper, flow fields within flames stabilized by combinations of swirl flow and bluff-body were captured using high-speed PIV; while the flame structures were visualized by high-speed CH2O PLIF, CH∗ chemiluminescence and broadband chemiluminescence. The global CO emissions from the flames were captured as well. In addition, based on the CFD software OpenFOAM, simulations were adopted to better understand the interactions between flames and flow structures. Flames stabilized by bluff-bodies with different diameters (db = 14 mm and 20 mm), or only by swirl flow without a bluff-body, were studied. All reacting experiments were carried out with a constant mass flow rate of the central fuel jet (with thermal power 2.01 kW) and a constant mass flow rate of the total air flow (m = mt + ma = 200 ln/min). The swirl strength was controlled by the mass flow rate ratio of the tangential to the axial air flow. The geometrical swirl number was altered between Sg = 0 and Sg = 4.08. Simulation results matched well with experimental data, especially in predicting the spatial distribution of CH2O. The position of the outer recirculation zone would be affected by the size of the bluff-body and the swirl strength. In addition, the recirculation zone determined the flame structures and the global CO emission levels. With a larger bluff-body, the air driven recirculation zone located more upstream near the burner exit. Flame prone to be more stable with a larger bluff-body and/or a stronger swirl flow. Flame was observed propagating into the upstream region in cases without a bluff-body or in cases with the small bluff-body (db = 14 mm), when the swirl strength was sufficiently strong. The mechanism for the diffusion flame ‘flashback’ was proposed. Flames in cases with a larger swirl number were shorter while its CO emission levels were higher.

    更新日期:2018-01-04
  • Understanding chemistry-specific fuel differences at a constant RON in a boosted SI engine
    Fuel (IF 4.601) Pub Date : 2018-01-02
    James P. Szybist, Derek A. Splitter

    The goal of the US Department of Energy Co-Optimization of Fuels and Engines (Co-Optima) initiative is to accelerate the development of advanced fuels and engines for higher efficiency and lower emissions. A guiding principle of this initiative is the central fuel properties hypothesis (CFPH), which states that fuel properties provide an indication of a fuel’s performance, regardless of its chemical composition. This is an important consideration for Co-Optima because many of the fuels under consideration are from bio-derived sources with chemical compositions that are unconventional relative to petroleum-derived gasoline or ethanol. In this study, we investigated a total of seven fuels in a spark ignition engine under boosted operating conditions to determine whether knock propensity is predicted by fuel antiknock metrics: antiknock index (AKI), research octane number (RON), and octane index (OI). Six of these fuels have a constant RON value but otherwise represent a wide range of fuel properties and chemistry. Consistent with previous studies, we found that OI was a much better predictor of knock propensity that either AKI or RON. However, we also found that there were significant fuel-specific deviations from the OI predictions. Combustion analysis provided insight that fuel kinetic complexities, including the presence of pre-spark heat release, likely limits the ability of standardized tests and metrics to accurately predict knocking tendency at all operating conditions. While limitations of OI were revealed in this study, we found that fuels with unconventional chemistry, in particular esters and ethers, behaved in accordance with CFPH as well as petroleum-derived fuels.

    更新日期:2018-01-04
  • Oxidative pyrolysis of mallee wood biomass, cellulose and lignin
    Fuel (IF 4.601) Pub Date : 2018-01-02
    Shengjuan Jiang, Xun Hu, Liping Wu, Lei Zhang, Shuai Wang, Tingting Li, Daohong Xia, Chun-Zhu Li

    The oxidative pyrolysis of mallee wood, cellulose and lignin was performed and the bio-oil products were analysed to understand how the externally added oxygen react with the pyrolysis products. Both wood cylinders of diameter 8 mm and fine particles (90–300 μm) were pyrolysed in this study to understand the combined effects of biomass particle size and the presence of oxygen. The results revealed that, at a low oxygen concentration, the gas-phase oxidation of volatiles would improve the yields of levoglucosan and syringaldehyde, as well as unsaturated hydroxyl ketones/aldehydes for small wood particles through the oxygen-induced radical reactions. Although oxygen could facilitate the production of some compounds in bio-oil through the gas-phase reactions, it did lead to decreases in the heavy bio-oil yield due to the over-oxidation of some pyrolysis products (e. g. aromatics, lactones, unconjugated alkyl aldehydes/esters and carboxylic acids). The effects of oxygen on the pyrolysis of wood cylinders were more complicated than mallee wood particles due to the secondary reactions of volatiles and the reactions involving the pyrolysing particle surface. The interactions between the polysaccharide-derived and lignin-derived products in gas phase might affect the oxidation of volatiles, changing the formation of pyrolytic products (e.g. levoglucosan and syringaldehyde).

    更新日期:2018-01-04
  • Steam reforming of acetic acid over Ni/Al2O3 catalysts: Correlation of nickel loading with properties and catalytic behaviors of the catalysts
    Fuel (IF 4.601) Pub Date : 2018-01-02
    Zhanming Zhang, Xun Hu, Jiaojiao Li, Guanggang Gao, Dehua Dong, Roel Westerhof, Song Hu, Jun Xiang, Yi Wang
    更新日期:2018-01-04
  • Assessing thermal and optical properties of biodiesel by thermal lens spectrometry: Theoretical and experimental aspects
    Fuel (IF 4.601) Pub Date : 2018-01-02
    Elton L. Savi, Leandro S. Herculano, Gustavo V.B. Lukasievicz, Helton R. Regatieri, Alex S. Torquato, Luis C. Malacarne, Nelson G.C. Astrath
    更新日期:2018-01-04
  • Catalytic thermal cracking of Athabasca VR in a closed reactor system
    Fuel (IF 4.601) Pub Date : 2018-01-02
    Afrooz Eshraghian, Maen M. Husein
    更新日期:2018-01-04
  • Enhanced production of microbial lipids from waste office paper by the oleaginous yeast Cryptococcus curvatus
    Fuel (IF 4.601) Pub Date : 2018-01-02
    Neelamegam Annamalai, Nallusamy Sivakumar, Piotr Oleskowicz-Popiel
    更新日期:2018-01-04
  • Study on the release characteristics of chlorine in coal gangue under leaching conditions of different pH values
    Fuel (IF 4.601) Pub Date : 2018-01-02
    Bingxian Peng, Xinrui Li, Weihua Zhao, Lan Yang

    A series of leaching experiments were carried out for evaluation of release behavior of Cl in Chinese coal gangue from Yangquan Coal Mine in Shanxi province under different pH conditions (pH = 2.6, 4.2, 6.5, 8.1, respectively) and different leaching durations (up to 105 h). The modes of occurrence of Cl in the coal gangue and its post-leached residues were extracted with sequential chemical extractions; chlorine in solution was determined using IC (ion chromatography); chemical and mineralogical compositions in coal gangue and the post-leached residues were determined by XRD (X-ray diffraction), XRF (X-ray fluorescence spectrum) and FT-IR (Fourier infrared spectrum). The results indicated that kaolinite, quartz, calcite, pyrite and illite were the predominant minerals in coal gangue with a certain amount of organic matter and a little mica. Chlorine in coal gangue occurred in a descending order of significance, as forms of organic matter (P5), Fe-Mn oxides (P4), water-soluble (P1), residue (P6), carbonate (P3), and exchangeable (P2), which accounted for 41.56%, 37.87%, 14.65%, 3.26%, 1.33% and 1.31%, respectively. With the rise of acidity of leaching solution, the reaction rates of most of matrix compositions in coal gangue increased, and more Cl was leached out in a shorter time. Under the condition of pH 2.6, 4.2, 6.5 and 8.1 and leaching duration up to 105 h, the leaching rate of Cl were respectively 57.21% (11.98%, 1.31%, 1.33%, 23.03% and 20.06% for P1, P2, P3, P4 and P5, respectively), 35.97% (8.18%, 1.31%, 0.78%, 14.77% and 10.91% for P1, P2, P3, P4 and P5, respectively), 26.65% (7.52%, 1.31%, 0.42%, 9.87% and 7.53% for P1, P2, P3, P4 and P5, respectively) and 18.98% (5.32%, 0.60%, 1.33%, 7.61% and 5.45% for P1, P2, P3, P4 and P5, respectively). Chlorine in coal gangue may pose an environmental risk with the increase of acidity of environmental aqueous solution.

    更新日期:2018-01-04
  • Fine coal desulfurization and modeling based on high-gradient magnetic separation by microwave energy
    Fuel (IF 4.601) Pub Date : 2018-01-02
    Bo Zhang, Guangqing Zhu, Zongsheng Sun, Guanghui Yan, Hao Yao
    更新日期:2018-01-04
  • Quantitative synthesis of 2,5-bis(hydroxymethyl)furan from biomass-derived 5-hydroxymethylfurfural and sugars over reusable solid catalysts at low temperatures
    Fuel (IF 4.601) Pub Date : 2018-01-02
    Wenfeng Zhao, Weibo Wu, Hu Li, Chengjiang Fang, Tingting Yang, Zhongwei Wang, Chao He, Song Yang
    更新日期:2018-01-04
  • An experimental and numerical study of wellbore leakage mitigation using pH-triggered polymer gelant
    Fuel (IF 4.601) Pub Date : 2018-01-03
    Shayan Tavassoli, Jostine Fei Ho, Mohammadreza Shafiei, Chun Huh, Paul Bommer, Steven Bryant, Matthew T. Balhoff

    The potential leakage of hydrocarbon fluids or carbon dioxide from subsurface formations is a primary concern in wellbore integrity, oil and gas production, and CO2 storage. Leaky wells with fractured cement or debonded microannuli are common sources of subsurface fluid leakage. The hydrocarbon fluid or CO2 can migrate through such pathways to shallower formations and ultimately to surface. Cement fractures may have apertures on the order of microns, which are difficult to seal with typical workover techniques. A material that provides low viscosity during the injection but much higher viscosity after injection, with a minimum pressure gradient to yield flow at the target zone, is a potentially effective approach to seal the leakage pathways through cement fractures. pH-triggered polymers are such a material: aqueous solutions with low viscosity at low pH, containing pH-sensitive microgels which viscosify upon neutralization to become highly swollen gels with substantial yield stress that can block fluid flow. For the wellbore leakage application, the large alkalinity of wellbore cement provides the required neutralization. Our coreflood and rheological experiments show that pH-triggered polymer sealants such as polyacrylic acid polymer provide a robust seal if the process is properly designed; however, its long-term applicability depends on the dynamic geochemical environment of the wellbore. The process comprises three stages: (1) injection of a chelating agent as the preflush to ensure a favorable environment for the polymer gel, (2) injection of polymer solution, and (3) shut-in for the polymer gelation. A systematic study was done to understand the conditions under which the polymer gel remains stable and effectively seals the leakage pathways. A numerical model, based on polymer rheological properties and governing mechanisms observed in the laboratory experiments, was developed to simulate the reactive flow and transport of pH-triggered polymers in narrow fractures. Comparison with experiments shows a generally good agreement, despite the relative simplicity of the model. The numerical model was used to investigate further the underlying mechanisms of the process. The results can be used to design effectively the remediation process for a known fracture aperture size of the target zone.

    更新日期:2018-01-04
  • Assessment of single-serpentine PEM fuel cell model developed by computational fluid dynamics
    Fuel (IF 4.601) Pub Date : 2018-01-02
    Elif Eker Kahveci, Imdat Taymaz

    In this study, a three-dimensional, single-phase model has been established to investigate the performance of proton exchange membrane fuel cell (PEMFC) with serpentine flow fields. The model was operated in the temperature range of 333–353 K, the pressure range of 1–3 atm, gas diffusion layer (GDL) range of 0.3–0.6, both anode and cathode relative humidity range (RH) of 10–100%. The current density and power density of PEM fuel cell was measured according to these varying operation parameters. The V-I characteristic of PEMFC was obtained for these different values of input parameters. The numerical simulation was realized with a PEM fuel cell model based on the FLUENT computational fluid dynamics (CFD) software. The performance of a PEM fuel cell increases with the increase of operating pressure because of partial pressure and diffusivity of reactant gases resulting in decreasing the mass transport resistance. It is also found that temperature has an important effect on the performance of PEMFC by the results of study. Even though after exceeding a definite temperature cell performance decreases. The results showed that the maximum power density was reached with 0.6 GDL porosity, RHa = 100% and RHc = 10% and the value of pressure of 3 atm. Also simulation results were compared with the experimental data reported in literature and showed good agreement between the model and experimental results.

    更新日期:2018-01-04
  • Utilization of microalgae feedstock for concomitant production of bioethanol and biodiesel
    Fuel (IF 4.601) Pub Date : 2018-01-03
    Ramachandran Sivaramakrishnan, Aran Incharoensakdi

    The present study focuses on the biorefinery approach of integrated production of bioethanol and biodiesel from microalgae feedstock. Various pretreatment methods were used to determine the maximum recovery of sugars from Scenedesmus sp. The total sugar yield of 93% was obtained when the biomass was pretreated by acid hydrolysis. The hydrolysate produced 86% of ethanol (theoretical yield) after the fermentation using Saccharomyces cerevisiae. Enzyme catalyzed direct transesterification of the biomass was performed using dimethyl carbonate as a solvent and the maximum yield of 92% methyl ester, 1.86% glycerol carbonate and 4.93% glycerol dicarbonate was achieved. The integrated process of bioethanol and biodiesel production was optimally achieved when direct transesterification was done first followed by ethanol fermentation yielding 92 and 93% of methyl ester and ethanol, respectively.

    更新日期:2018-01-04
  • Numerical analysis of a gas turbine combustor fueled by hydrogen in comparison with jet-A fuel
    Fuel (IF 4.601) Pub Date : 2018-01-02
    Nafiz Kahraman, Selim Tangöz, S.Orhan Akansu

    The interest in alternative fuels has increased in recent years. Because, the conventional fuels have the danger of extinction in the near future and these fuels harm the environment. Therefore, in this study, the availability of hydrogen as an alternative fuel has been investigated in the tubular combustion chamber of a gas turbine engine fueled by jet-A fuel. For this purpose, the combustion characteristics in the combustor of a Rolls-Royce Nene turbojet engine fueled by gas jet-A and hydrogen have been numerically studied at different excess air ratios (EAR) for a given thermal power values. Temperature distributions in the combustor, combustion efficiency, pressure drop and velocity change have been numerically analyzed at 1480 kW (10000 rpm), 2290 kW (11000 rpm) and 2980 kW (12000 rpm) thermal power in the combustion chamber. The RNG k- turbulence and eddy-dissipation combustion models have been used for 2D axisymmetric geometry with swirling flow. The combustion efficiency and the pressure drop values are increasing with an increase in the EAR values. But, the outlet temperature values of the combustion chamber, the CO2 emissions and unburned HC emissions are decreasing by increasing of the EAR values. Moreover, it is observed that the NOx emission values are increasing and then are decreasing with the EAR values. The combustion of hydrogen is seen as advantageous in terms of pressure drop, temperature values at the combustion chamber outlet and CO2 and unburned HC emissions. In addition, it can be seen that as advantageous in terms of the NOx emission values at low EAR values but as disadvantageous at high EAR values.

    更新日期:2018-01-04
  • Investigation of the effect of nozzle inlet rounding on diesel spray formation and combustion
    Fuel (IF 4.601) Pub Date : 2018-01-02
    Ozgur Oguz Taskiran

    In this study, the effect of nozzle inlet rounding on diesel spray formation and combustion is investigated. In order to take into account nozzle geometry, two different nozzle geometries (sharp inlet and rounded inlet) were used in the experiments. Diesel spray injected into a constant volume combustion chamber was modeled by using KIVA3V R2 code. One dimensional nozzle flow model was used in numerical simulations. This model calculates nozzle discharge coefficient and updates the initial droplet radius and droplet velocities according to nozzle inlet geometry. Diesel fuel is represented by diesel oil surrogate mechanism which consists of 71 species and 323 reactions. The numerical spray results were validated with macroscopic spray characterization data obtained by constant volume experiments. Results showed that inlet rounding increases discharge coefficient. At high ambient pressure conditions, sharp and rounded nozzles have similar spray internal structure. However, it is observed that sharp inlet nozzle produces smaller droplets that shorten spray tip penetration and autoignition delay period due to low discharge coefficient. Comparing spray combustion of rounded and sharp inlet nozzles, it is showed that rounded inlet nozzle has lower combustion temperature, less NO and soot concentration than sharp inlet nozzle.

    更新日期:2018-01-04
  • Dimensionally reduced modeling of nitric oxide formation for premixed methane-air flames with ammonia content
    Fuel (IF 4.601) Pub Date : 2018-01-02
    Joanna Jójka, Rafał Ślefarski

    The paper presented an experimental and numerical study on a combustion process of ammonia doped methane flames with the NH3 content in the fuel from 1% up to 5%. Tests were performed with an atmospheric pressure axisymmetric burner for stoichiometric mixtures and fuel-lean conditions (φ = 0.63, 0.71, 0.83, 1.0) with the substrates preheating up to 573 K. Numerical modelling involved three reduced dimensionally combustion models (0D IdealGasReactor, 1D FreeFlame, 1D BurnerFlame) with four detailed reaction mechanisms for the hydrocarbons and nitrogen chemistry (GRI 3.0, SanDiego, Konnov 0.6 and Tian). Comparison of the 0D/1D calculations results with a complete burner geometry modelling (3D Ansys EDC) was performed for GRI 3.0. Experimental study shown that nitric oxide emission increased with the increase of NH3 content in the introduced fuel, however transition from NH3 to NO was incomplete and trend was not linear for the rising ammonia share. Doubling of the ammonia content in the fuel from 2.5% to 5% resulted in a rise of NO emission by only 55.5% (from 946 to 1471 ppmv) for the lean mixtures and by 48% (from 1451 to 2148 ppmv) for the stoichiometric conditions. The numerical analysis results were in a good agreement with the experimental results for the lean mixtures and ammonia content up to 1% for all investigated combustion models and the kinetic reaction mechanisms. Trends of the nitric oxide emission obtained with the stoichiometric flames were valid for 1D models. However overall values were over predicted for an adiabatic 1D FreeFlame calculations and under predicted for 1D BurnerFlame, which showed a sensitivity of the nitrogen chemistry to the process temperature. Analysis with the 3D Ansys EDC model and GRI 3.0 provided the most accurate results up to 2.5% of the NH3 share in the fuel with a maximum relative differences values to the experimental results from 10% up to 24% for the lean and the stoichiometric conditions respectively.

    更新日期:2018-01-04
  • Experimental investigation on the effects of nozzle-hole number on combustion and emission characteristics of ethanol/diesel dual-fuel engine
    Fuel (IF 4.601) Pub Date : 2017-12-22
    Shijun Dong, Can Yang, Biao Ou, Hongguang Lu, Xiaobei Cheng

    Since fuel reactivity stratification greatly influences the combustion process of dual-fuel engines and nozzle geometry directly affects the distribution of direct injected fuel, experiments were carried out to investigate the effects of nozzle-hole number on the combustion and emissions of dual-fuel engine. The experiments were performed on a single-cylinder diesel engine with port injection of ethanol and direct injection of diesel. There are four diesel injectors with 4, 5, 6 and 8 nozzle holes studied in this paper, while the total orifice areas and included spray angles of the injectors are kept the same. With reduced nozzle holes, the experimental results showed that both the in-cylinder peak pressure and PPRR (peak pressure rise rate) of ethanol/diesel dual-fuel combustion were decreased while with extended combustion durations. This is mainly because the number of high fuel reactivity regions was reduced with fewer diesel sprays, then the combustion of premixed ethanol was slowed down which consequently decreased the heat release rate. With reduced nozzle holes, the engine-out NOx emissions were decreased, and soot emissions were slightly increased while still maintained at quite low level. The UHC and CO emissions were slightly increased with reduced nozzle holes which resulted in lower combustion efficiency. However, the influences of nozzle-hole number on dual-fuel combustion were gradually decreased with advanced injection, which was mainly because of the enhanced diesel/air mixing. The experimental results indicated that dual-fuel combustion with reduced nozzle holes could achieve moderate heat release with lower PPRR.

    更新日期:2017-12-27
Some contents have been Reproduced with permission of the American Chemical Society.
Some contents have been Reproduced by permission of The Royal Society of Chemistry.
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