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Complete oxidation of methane on CoO-SnO catalysts

Xingfu TANG , Jiming HAO , Junhua LI ,

《环境科学与工程前沿（英文）》 2009年第3卷第3期页码 265-270 doi: 10.1007/s11783-009-0019-2

摘要： CoO-SnO hybrid oxides were prepared by the coprecipitation method and were used to oxidate methane (CH) in presence of oxygen. The CoO-SnO with a molar ratio of Co/(Co+Sn) at 0.75 exhibited the highest catalytic activity among all the CoO-SnO hybrid oxides. Experimental results showed that the catalysts were considerably stable in the CH combustion reaction, and were verified by X-ray photoelectron spectra (XPS). It was found that CoO was the active species, and SnO acted as a support or a promoting component in the CoO-SnO hybrid oxides. The surface area was not a major factor that affected catalytic activity. The hydrogen temperature-programmed reduction (H-TPR) results demonstrated that the interaction between cobalt and tin oxides accelerated the mobility of oxygen species of CoO-SnO, leading to higher catalytic activity.

关键词： Co₃O₄-SnO₂ complete oxidation methane (CH₄)

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CH4sub> and N2sub>O emissions from double-rice cropping system as affected by Chinese milk

Heshui XU,Dengyun LI,Bo ZHU,Kai ZHANG,Yadong YANG,Chen WANG,Ying JIANG,Zhaohai ZENG

《农业科学与工程前沿（英文）》 2017年第4卷第1期页码 59-68 doi: 10.15302/J-FASE-2017137

摘要： Chinese milk vetch (CMV) and rice straw (RS) were incorporated into soil to substitute for synthetic N fertilizers and to maintain soil fertility. However, little is known about the integrated impacts of CMV and RS incorporation on CH and N O emissions in double-rice cropping systems in southern China. A field experiment was conducted to estimate the integrated impacts of CMV and RS incorporation in the early- and late-rice seasons on CH and N O emissions. All treatments received uniform N inputs, 6%–37% of which was replaced by CMV and RS crop residue. CMV and/or RS incorporation produced equivalent or slightly more grain yield, while reducing N O emissions by 3%–43%. However, both CMV and RS incorporation increased CH emissions. Annual CH emissions ranged from 321 to 614 kg·hm from CMV and RS amendment treatments, which were 1.5–2.9 times higher than that from synthetic N. Compared with single synthetic N fertilizer, incorporation of CMV and/or RS increased GWP and yield-scaled GWP by 45%–164% and 45%–153%, respectively. Our results demonstrate CMV and RS amendments replacing N fertilizer, maintained stable yield, mitigated N O emission, but enhanced CH emission. Further study is needed on crop residue management in double-cropping rice systems.

关键词： Chinese milk vetch CH₄ double-rice cropping system grain yield N₂O rice straw

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Review on cryogenic technologies for CO removal from natural gas

Yujing BI, Yonglin JU

《能源前沿（英文）》 2022年第16卷第5期页码 793-811 doi: 10.1007/s11708-022-0821-0

摘要： CO₂ in natural gas (NG) is prone to condense directly from gas to solid or solidify from liquid to solid at low temperatures due to its high triple point and boiling temperature, which can cause a block of equipment. Meanwhile, CO₂ will also affect the calorific value of NG. Based on the above reasons, CO₂ must be removed during the NG liquefaction process. Compared with conventional methods, cryogenic technologies for CO₂ removal from NG have attracted wide attention due to their non-polluting and low-cost advantages. Its integration with NG liquefaction can make rational use of the cold energy and realize the purification of NG and the production of by-product liquid CO₂. In this paper, the phase behavior of the CH₄-CO₂ binary mixture is summarized, which provides a basis for the process design of cryogenic CO₂ removal from NG. Then, the detailed techniques of design and optimization for cryogenic CO₂ removal in recent years are summarized, including the gas-liquid phase change technique and the gas-solid phase change technique. Finally, several improvements for further development of the cryogenic CO₂ removal process are proposed. The removal process in combination with the phase change and the traditional techniques with renewable energy will be the broad prospect for future development.

关键词： cryogenic CO₂ removal purification of natural gas (NG) biogas upgrading CH₄-CO₂ binary system

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Effect of TiO

Navid Azizi, Mojgan Isanejad, Toraj Mohammadi, Reza M. Behbahani

《化学科学与工程前沿（英文）》 2019年第13卷第3期页码 517-530 doi: 10.1007/s11705-018-1781-0

摘要： Membranes have attracted much attention as economical methods for industrial chemical processes. The effects of the titanium dioxide nanoparticle load on the morphology and CO /CH separation performance of poly (ether-block-amide) (PEBAX-1657) mixed matrix membranes (MMMs) were investigated from pressures of 3–12 bar and temperatures of 30°C–60°C. The PEBAX membranes were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, thermal gravimetric analysis, atomic force microscopy and tensile strength analysis. The incorporation of TiO nanoparticles into the polymeric MMMs improved the CO /CH gas separation performance (both the permeability and selectivity) of the membranes. The CO permeability and ideal CO /CH selectivity values of the nanocomposite membrane loaded with 8 wt-% TiO were 172.32 Barrer and 24.79, respectively whereas those of the neat membrane were 129.87 Barrer and 21.39, respectively.

关键词： mixed matrix membrane TiO₂ nanoparticles PEBAX-1657 CO₂/CH₄ separation

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Ni-Co bimetallic catalyst for CH

Xiaohong LI, Jun AI, Wenying LI, Dongxiong LI

《化学科学与工程前沿（英文）》 2010年第4卷第4期页码 476-480 doi: 10.1007/s11705-010-0512-y

摘要： A co-precipitation method was employed to prepare Ni/Al O -ZrO , Co/Al O -ZrO and Ni-Co/Al O -ZrO catalysts. Their properties were characterized by N adsorption (BET), thermogravimetric analysis TGA , temperature-programmed reduction (TPR), temperature-programmed desorption (CO -TPD), and temperature-programmed surface reaction (CH -TPSR and CO -TPSR). Ni-Co/Al O -ZrO bimetallic catalyst has good performance in the reduction of active components Ni, Co and CO adsorption. Compared with mono-metallic catalyst, bimetallic catalyst could provide more active sites and CO adsorption sites (C+ CO = 2CO) for the methane-reforming reaction, and a more appropriate force formed between active components and composite support (SMSI) for the catalytic reaction. According to the CH -CO -TPSR, there were 80.9% and 81.5% higher CH and CO conversion over Ni-Co/Al O -ZrO catalyst, and its better resistance to carbon deposition, less than 0.5% of coke after 4 h reaction, was found by TGA. The high activity and excellent anti-coking of the Ni-Co/Al O -ZrO catalyst were closely related to the synergy between Ni and Co active metal, the strong metal-support interaction and the use of composite support.

关键词： Ni-Co bimetallic catalyst composite support CH₄ reforming with CO₂

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Effect of carbon deposition over carbonaceous catalysts on CH

Yongfa ZHANG, Meng ZHANG, Guojie ZHANG, Huirong ZHANG

《化学科学与工程前沿（英文）》 2010年第4卷第4期页码 481-485 doi: 10.1007/s11705-010-0523-8

摘要： An investigation was made using a continuous fixed bed reactor to understand the influence of carbon deposition obtained under different conditions on CH -CO reforming. Thermogravimetry (TG) and X-ray diffraction (XRD) were employed to study the characteristics of carbon deposition. It was found that the carbonaceous catalyst is an efficient catalyst in methane decomposition and CH -CO reforming. The trend of methane decomposition at lower temperatures is similar to that at higher temperatures. The methane conversion is high during the initial of stage of the reaction, and then decays to a relatively fixed value after about 30 min. With temperature increase, the methane decomposition rate increases quickly. The reaction temperature has significant influence on methane decomposition, whereas the carbon deposition does not affect methane decomposition significantly. Different types of carbon deposition were formed at different methane decomposition reaction temperatures. The carbon deposition Type I generated at 900°C has a minor effect on CH -CO reforming and it easily reacts with carbon dioxide, but the carbon deposition Type II generated at 1000°C and 1100°C clearly inhibits CH -CO reforming and it is difficult to react with carbon dioxide. The results of XRD showed that some graphite structures were found in carbon deposition Type II.

关键词： carbon deposition carbonaceous catalyst CH₄-CO₂ reforming

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Design and analysis of dual fuel methanol-power poly-generation

Minghua WANG , Zheng LI , Weidou NI ,

《能源前沿（英文）》 2009年第3卷第3期页码 341-347 doi: 10.1007/s11708-009-0023-z

摘要： A dual fuel head poly-generation flowsheet was designed based on coal gas and coke oven gas. To help clearly understand the system performance, a 1.2×10−3.2×10kg methanol and 274―496MW power poly-generation system was simulated by using the commercially available software ASPEN Plus and GT Pro. The technology scheme, the operating parameters, and the efficiency of the system were also analyzed and evaluated, which will be used for building industrial devices.

关键词： dual fuel methanol-power poly-generation CO₂ and CH₄ reforming splitting ratio

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A density functional theory study of methane activation on MgO supported NiM cluster: role of M on C–H activation

《化学科学与工程前沿（英文）》 2022年第16卷第10期页码 1485-1492 doi: 10.1007/s11705-022-2169-8

摘要： Methane activation is a pivotal step in the application of natural gas converting into high-value added chemicals via methane steam/dry reforming reactions. Ni element was found to be the most widely used catalyst. In present work, methane activation on MgO supported Ni–M (M = Fe, Co, Cu, Pd, Pt) cluster was explored through detailed density functional theory calculations, compared to pure Ni cluster. CH₄ adsorption on Cu promoted Ni cluster requires overcoming an energy of 0.07 eV, indicating that it is slightly endothermic and unfavored to occur, while the adsorption energies of other promoters M (M = Fe, Co, Pd and Pt) are all higher than that of pure Ni cluster. The role of M on the first C–H bond cleavage of CH₄ was investigated. Doping elements of the same period in Ni cluster, such as Fe, Co and Cu, for C–H bond activation follows the trend of the decrease of metal atom radius. As a result, Ni–Fe shows the best ability for C–H bond cleavage. In addition, doping the elements of the same family, like Pd and Pt, for CH₄ activation is according to the increase of metal atom radius. Consequently, C–H bond activation demands a lower energy barrier on Ni–Pt cluster. To illustrate the adsorptive dissociation behaviors of CH₄ at different Ni–M clusters, the Mulliken atomic charge was analyzed. In general, the electron gain of CH₄ binding at different Ni–M clusters follows the sequence of Ni–Cu (–0.02 e) < Ni (–0.04 e) < Ni–Pd (–0.08 e) < Ni–Pt (–0.09 e) < Ni–Co (–0.10 e) < Ni–Fe (–0.12 e), and the binding strength between catalysts and CH ₄ raises with the CH₄ electron gain increasing. This work provides insights into understanding the role of promoter metal M on thermal-catalytic activation of CH₄ over Ni/MgO catalysts, and is useful to interpret the reaction at an atomic scale.

关键词： CH₄ dissociation Ni–M C–H bond activation charge transfer

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Greenhouse gas emissions during co-composting of cattle feedlot manure with construction and demolition (C&D) waste

Xiying Hao, Francis J. Larney

《环境科学与工程前沿（英文）》 2017年第11卷第3期 doi: 10.1007/s11783-017-0955-1

摘要： Manure management strategies should reflect current animal feeding practices and encourage recycling of organic waste to help protect our environment. This research investigated greenhouse gas (GHG) emissions during cattle manure stockpiling or composting with and without construction and demolition (C&D) waste. Manure was collected from cattle fed a typical finishing diet (CK manure) and from cattle on diets which included 30% dried distillers grains with solubles (DG manure). The CK and DG manures were co-composted with (4:1) C&D waste (treatments: CK_CD DG_CD), composted alone (treatments: CK and DG) in 13 m bins or stockpiled without C&D waste (treatments: CK_ST and DG_ST) for 99 days. Manure type (CK vs. DG manure) had no effect on GHG emissions over the 99 day manure composting or stockpiling. Composting with C&D waste produced similar CO emissions, about double that from manure stockpiling (7.0 kgC·m ). In contrast, CH emissions were reduced by the inclusion of C&D waste (64 gC·m with C&D vs. 244 gC·m without C&D) while the manure stockpile emitted the greatest amount of CH (464 gC·m ). Additionally, only 0.48% of C was emitted in CH form with C&D waste, compared to 1.68% when composting without C&D waste and 7.00% when cattle manure was stockpiled. The N O emissions (12.4 to 18.0 gN·m ) were similar across all treatments. The lower CH emissions with C&D waste are beneficial in reducing overall GHG emissions from manure composting, while reducing the amount of material entering landfills.

关键词： Livestock manure greenhouse gas flux straw bale compost bin N₂O CH₄ CO₂

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Li4sub>SiO4sub>-coated LiNi0.5sub>Mn1.5sub>O4sub> as the high performance

Shifeng YANG, Wenfeng REN, Jian CHEN

《能源前沿（英文）》 2017年第11卷第3期页码 374-382 doi: 10.1007/s11708-017-0494-2

摘要： The preparation of Li SiO -coated LiNi Mn O materials by sintering the SiO -coated nickel-manganese oxides with lithium salts using abundant and low-cost sodium silicate as the silicon source was reported. The samples were characterized by X-ray diffraction, scanning electron microscopy and transmission electron microscopy. It was found that a uniform and complete SiO coating layer could be obtained at a suitable pH value of 10, which transformed to a good Li SiO coating layer afterwards. When used as the cathode materials for lithium-ion batteries, the Li SiO -coated LiNi Mn O samples deliver a better electrochemical performance in terms of the discharge capacity, rate capability, and cycling stability than that of the pristine material. It can still deliver 111.1 mAh/g at 20 C after 300 cycles, with a retention ratio of 93.1% of the stable capacity, which is far beyond that of the pristine material (101.3 mAh/g, 85.6%).

关键词： lithium-ion batteries cathode material LiNi_0.5Mn_1.5O₄ lithium-ion conductor coating

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Rh2sub>O3sub>/hexagonal CePO4sub> nanocatalysts for N2sub>O decomposition

Huan Liu, Zhen Ma

《化学科学与工程前沿（英文）》 2017年第11卷第4期页码 586-593 doi: 10.1007/s11705-017-1659-6

摘要： Hexagonal CePO nanorods were prepared by a precipitation method and hexagonal CePO nanowires were prepared by hydrothermal synthesis at 150 °C. Rh(NO ) was then used as a precursor for the impregnation of Rh O onto these CePO materials. The Rh O supported on the CePO nanowires was much more active for the catalytic decomposition of N O than the Rh O supported on CePO nanorods. The stability of both catalysts as a function of time on stream was studied and the influence of the co-feed (CO , O , H O or O /H O) on the N O decomposition was also investigated. The samples were characterized by N adsorption-desorption, inductively coupled plasma optical emission spectroscopy, X-ray diffraction, transmission electron microscopy, X-ray photoelectron microscopy, hydrogen temperature-programmed reduction, oxygen temperature-programmed desorption, and CO temperature-programmed desorption in order to correlate the physicochemical and catalytic properties.

关键词： Rh₂O₃ CePO₄ N₂O decomposition

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Greenhouse gas emissions from different pig manure management techniques: a critical analysis

Conor Dennehy, Peadar G. Lawlor, Yan Jiang, Gillian E. Gardiner, Sihuang Xie, Long D Nghiem, Xinmin Zhan

《环境科学与工程前沿（英文）》 2017年第11卷第3期 doi: 10.1007/s11783-017-0942-6

摘要： Manure management is the primary source of greenhouse gas (GHG) emissions from pig farming, which in turn accounts for 18% of the total global GHG emissions from the livestock industry. In this review, GHG emissions (N O and CH emissions in particular) from individual pig manure (PGM) management practices (European practises in particular) are systematically analyzed and discussed. These manure management practices include manure storage, land application, solid/liquid separation, anaerobic digestion, composting and aerobic wastewater treatment. The potential reduction in net GHG emissions by changing and optimising these techniques is assessed. This review also identifies key research gaps in the literature including the effect of straw covering of liquid PGM storages, the effect of solid/liquid separation, and the effect of dry anaerobic digestion on net GHG emissions from PGM management. In addition to identifying these research gaps, several recommendations including the need to standardize units used to report GHG emissions, to account for indirect N O emissions, and to include a broader research scope by conducting detailed life cycle assessment are also discussed. Overall, anaerobic digestion and compositing to liquid and solid fractions are best PGM management practices with respect to their high GHG mitigation potential.

关键词： CH₄ N₂O Storage Anaerobic digestion Composting Separation

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ZnFe2sub>O4sub> deposited on BiOCl with exposed (001) and (010) facets for photocatalyticreduction of CO2sub> in cyclohexanol

Guixian Song, Xionggang Wu, Feng Xin, Xiaohong Yin

《化学科学与工程前沿（英文）》 2017年第11卷第2期页码 197-204 doi: 10.1007/s11705-016-1606-y

摘要： ZnFe O -BiOCl composites were prepared by both hydrothermal and direct precipitation processes and the structures and properties of the samples were characterized by various instrumental techniques. The samples were then used as catalysts for the photocatalytic reduction of CO in cyclohexanol under ultraviolet irradiation to give cyclohexanone (CH) and cyclohexyl formate (CF). The photocatalytic CO reduction activities over the hydrothermally prepared ZnFe O -BiOCl composites were higher than those over the directly-precipitated composites. This is because compared to the direct-precipitation sample, the ZnFe O nanoparticles in the hydrothermal sample were smaller and more uniformly distributed on the surface of BiOCl and so more heterojunctions were formed. Higher CF and CH yields were obtained for the pure BiOCl and BiOCl composite samples with more exposed (001) facets than for the samples with more exposed (010) facets. This is due to the higher density of oxygen atoms in the exposed (001) facets, which creates more oxygen vacancies, and thereby improves the separation efficiency of the electron-hole pairs. More importantly, irradiation of the (001) facets with ultraviolet light produces photo-generated electrons which is helpful for the reduction of CO to ·CO . The mechanism for the photocatalytic reduction of CO in cyclohexanol over ZnFe O -BiOCl composites with exposed (001) facets involves electron transfer and carbon radical formation.

关键词： reduction of CO₂ cyclohexanol ZnFe₂O₄ deposited BiOCl facet composite photocatalyst

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An investigation of the CHOH and CO selectivity of CO hydrogenation over Cu–Ce–Zr catalysts

《化学科学与工程前沿（英文）》 2022年第16卷第6期页码 950-962 doi: 10.1007/s11705-022-2162-2

摘要： A series of Cu–Ce–Zr catalysts with different Ce contents are applied to the hydrogenation of CO₂ to CO/CH₃OH products. The Cu–Ce–Zr catalyst with 2 wt% Ce loading shows higher CO selectivity (S_CO = 0.0%–87.8%) from 200–300 °C, while the Cu–Ce–Zr catalyst with 8 wt% Ce loading presents higher CO₂ conversion (

X C O 2

= 5.4%–15.6%) and CH₃OH selectivity (

S C H 3 O H

= 97.8%–40.6%). The number of hydroxyl groups and solid solution nature play a significant role in changing the reaction pathway. The solid solution enhances the CO₂ adsorption ability. At the CO₂ adsorption step, a larger number of hydroxyl groups over the Cu–Ce–Zr catalyst with 8 wt% Ce loading leads to the production of H-containing adsorption species. At the CO₂ hydrogenation step, a larger number of hydroxyl groups assists in encouraging the further hydrogenation of intermediate species to CH₃OH and improving the hydrogenation rate. Hence, the Cu–Ce–Zr catalyst with 8 wt% Ce loading favors CH₃OH selectivity and CO₂ activation, while CO is preferred on the Cu–Ce–Zr catalyst with 2 wt% Ce loading, a smaller number of hydroxyl groups and a solid solution nature. Additionally, high-pressure in situ diffuse reflectance infrared Fourier transform spectroscopy shows that CO is produced from formate decomposition and that both monodentate formate and bidentate formate are active intermediate species of CO₂ hydrogenation to CH₃OH.

关键词： CO₂ hydrogenation Cu–Ce–Zr hydroxyls CO/CH₃OH selectivity

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通过 B 位Ta置换对 AB O4sub>型EuNbO4sub>的热学和力学性质进行优化 Article

陈琳, 冯晶

《工程（英文）》 2020年第6卷第2期页码 177-184 doi: 10.1016/j.eng.2019.12.006

摘要：

铁弹性的ABO4sub>型RETaO4sub>陶瓷和RENbO4sub>陶瓷（RE表示稀土）是具有潜在应用价值的热障涂层（TBC）材料，结果显示， RETaO4sub>陶瓷的力学性质优于RENbO4sub>陶瓷的力学性质。在本研究中，我们通过B位钽（Ta）置换对利用固相法（SSR）制备的EuNbO4sub>陶瓷的热学和力学性质进行优化。;5 K⁻¹（1200 ℃）； EuNbO4sub>陶瓷的热导率被降低至1.52 W·K^–1&研究结果表明，通过B位Ta置换能够有效优化EuNbO4sub>的热学和力学性质，从而使得此种材料在将来可成为一种高温结构陶瓷材料。