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

《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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The catalytic effect of both oxygen-bearing functional group and ash in carbonaceous catalyst on CH 4

Weidong ZHANG, Yongfa ZHANG,

《化学科学与工程前沿（英文）》 2010年第4卷第2期页码 147-152 doi: 10.1007/s11705-009-0242-1

摘要： A kind of new catalyst—carbonaceous catalyst—for CH-CO reformation has been developed in our laboratory. The effect of both oxygen-bearing functional group such as phenolic hydroxyl, carbonyl, carboxyl, and lactonic, and ash such as FeO, NaCO, and KCO in the carbonaceous catalyst on the CH-CO reforming has been investigated with a fixed-bed reactor. It has been found that the carbonaceous catalyst is an efficient catalyst on CO-CH reforming. With the decrease of oxygen-bearing functional group, the catalytic activity of carbonaceous catalyst decreases quickly. The oxygen-bearing functional groups play a significant role in the carbonaceous-catalyzed CO-CH reforming; the ash components in carbonaceous catalyst also have an important influence on the CO-CH reforming. FeO, NaCO, and KCO in the ash can catalyze the CO-CH reforming reaction; CaO has little effect on CO-CH reforming reaction. CaO can catalyze the gasification between carbonaceous catalyst and CO; AlO and MgO inhibit the CO-CH reforming.

关键词： oxygen-bearing functional carboxyl phenolic hydroxyl CH-CO reformation CO-CH reforming

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CH₄ and N₂O 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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Frontier science and challenges on offshore carbon storage

《环境科学与工程前沿（英文）》 2023年第17卷第7期 doi: 10.1007/s11783-023-1680-6

摘要：

● The main direct seal up carbon options and challenges are reviewed.

关键词： Offshore carbon storage Direct CO₂ injection CO₂-CH₄ replacement CO₂-EOR CCS hubs CO₂ transport

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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 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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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 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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Dissolved methane in anaerobic effluent: Emission or recovery?

《环境科学与工程前沿（英文）》 2022年第16卷第4期 doi: 10.1007/s11783-022-1537-4

摘要： Various anaerobic processes have been explored for the energy-efficient treatment of municipal wastewater. However, dissolved methane in anaerobic effluent appears to be a barrier towards the energy and carbon neutrality of wastewater treatment. Although several dissolved methane recovery methods have been developed, their engineering feasibility and economic viability have not yet been assessed in a holistic manner. In this perspective, we thus intend to offer additional insights into the cost-benefit of dissolved methane recovery against its emission.

关键词： Anaerobic treatment Municipal wastewater Dissolved methane Methane recovery Carbon emission

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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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Artificial intelligence in gastroenterology: where are we heading?

Joseph JY Sung, Nicholas CH Poon

《医学前沿（英文）》 2020年第14卷第4期页码 511-517 doi: 10.1007/s11684-020-0742-4

摘要： Artificial intelligence (AI) is coming to medicine in a big wave. From making diagnosis in various medical conditions, following the latest advancements in scientific literature, suggesting appropriate therapies, to predicting prognosis and outcome of diseases and conditions, AI is offering unprecedented possibilities to improve care for patients. Gastroenterology is a field that AI can make a significant impact. This is partly because the diagnosis of gastrointestinal conditions relies a lot on image-based investigations and procedures (endoscopy and radiology). AI-assisted image analysis can make accurate assessment and provide more information than conventional analysis. AI integration of genomic, epigenetic, and metagenomic data may offer new classifications of gastrointestinal cancers and suggest optimal personalized treatments. In managing relapsing and remitting diseases such as inflammatory bowel disease, irritable bowel syndrome, and peptic ulcer bleeding, convoluted neural network may formulate models to predict disease outcome, enhancing treatment efficacy. AI and surgical robots can also assist surgeons in conducting gastrointestinal operations. While the advancement and new opportunities are exciting, the responsibility and liability issues of AI-assisted diagnosis and management need much deliberations.

关键词： artificial intelligence endoscopy robotics gastrointestinal diseases

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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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Online gasoline blending with EPA Complex Model for predicting emissions

Stefan JANAQI, Mériam CHÈBRE, Guillaume PITOLLAT

《工程管理前沿（英文）》 2018年第5卷第2期页码 214-226 doi: 10.15302/J-FEM-2017022

摘要： The empirical Complex Model developed by the US Environmental Protection Agency (EPA) is used by refiners to predict the toxic emissions of reformulated gasoline with respect to gasoline properties. The difficulty in implementing this model in the blending process stems from the implicit definition of Complex Model through a series of disjunctions assembled by the EPA in the form of spreadsheets. A major breakthrough in the refinery-based Complex Model implementation occurred in 2008 and 2010 through the use of generalized disjunctive and mixed-integer nonlinear programming (MINLP). Nevertheless, the execution time of these MINLP models remains prohibitively long to control emissions with our online gasoline blender. The first objective of this study is to present a new model that decreases the execution time of our online controller. The second objective is to consider toxic thresholds as hard constraints to be verified and search for blends that verify them. Our approach introduces a new way to write the Complex Model without any binary or integer variables. Sigmoid functions are used herein to approximate step functions until the measurement precision for each blend property is reached. By knowing this level of precision, we are able to propose an extremely good and differentiable approximation of the Complex Model. Next, a differentiable objective function is introduced to penalize emission values higher than the threshold emissions. Our optimization module has been implemented and tested with real data. The execution time never exceeded 1 s, which allows the online regulation of emissions the same way as other traditional properties of blended gasoline.

关键词： emissions reformulated gasoline online control global optimization