检索结果-南通市图书馆

Distribution of Carboxylic Acids in Sudanese Dar Crude Oil: Characterized by Negative-Ion Electrospray Ionization Fou- rier Transform Ion Cyclotron Resonance Mass Spectrometry

在线全文

学校读者我要写书评

暂无评论

china Petroleum Processing & Petrochemical Technology 2011年第4期13卷 15-22页

作者： Wang Zhenhua Tu Yongshan china tianchen engineering corporation Tianjin 300400 State Key Laboratory of Heavy Oil Processing China University of Petroleum Qingdao 266555

The Dar crude oil produced in Sudan was distilled into several fractions. The heteroatom class species in crude and its fractions were characterized by the negative-ion ESI FT-ICR MS. The major emphasis was put upon the study on the O2 class species (petroleum carboxylic acids). The test results revealed that aliphatic acids and monocyclic naphthenic acids accounted for a large proportion in petroleum carboxylic acids of the Dar crude. The relative abundance of aliphatic acids and monocyclic naphthenic acids decreased with an increasing boiling point of fractions. Meanwhile, the relative abundance of bicyclic and tricyclic naphthenic acids increased at first and then decreased, whereas the relative abundance of petroleum carboxylic acids with higher double-bond equivalence (DBE) values increased. The high abundance of aliphatic acids in the Dar crude and its fractions covered the carbon numbers in a range of 16 to 18 which had important geochemical signifi- cance. The O2 class species were distributed in a broad range of DBE values and carbon numbers with increasing boiling points of fractions.

关键词： O2 class species petroleum carboxylic acids DBE aliphatic acids naphthenic acids.

Comparison of Carboxylic Acids in Some Crude Oils and Their Diesel Distillates and VGOs:Characterized by Negative-Ion Electrospray Ionization Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (Negative-Ion ESI FT-ICR MS)

在线全文

学校读者我要写书评

暂无评论

china Petroleum Processing & Petrochemical Technology 2011年第3期13卷 8-15页

作者： Wang Zhenhua Tu Yongshan Process Department China Tianchen Engineering Corporation Tianjin 300400 State Key Laboratory of Heavy Oil Processing China University of Petroleum Qingdao 266555

Three high-acidity crudes, Dar, SZ36-1, and QHD326, were separated through distillation into several fractions, including diesel distillates, and VGOs. Samples were characterized by negative-ion ESI FT-ICR MS. The O2 class species （petroleum carboxylic acids）, which have a close relationship with corrosion of equipment caused by high-acidity crudes, were put in the focus of attention and were discussed in this paper. Monocyclic, bicyclic, and tricyclic naphthenic acids are the main types of petroleum carboxylic acids in naphthenic-base crudes （SZ36-1 and QHD326）. But the main types of petroleum carboxylic acids in paraffinic-base crude （Dar） are aliphatic acids and monocyclic naphthenic acids. The O2 class species in SZ36-1 and QHD326 are distributed in a wider range and have bigger DBE value （double-bond equivalence value） and carbon number than Dar. Bicyclic naphthenic acids have the highest proportion among petroleum carboxylie acids in diesel distillates, but monocyclic and tricyclic naphthenic acids also occupy a high proportion. Particularly, aliphatic acids in the diesel distillate of Dar still have high proportion among petroleum carboxylic acids. The distribution of petroleum carboxylic acids in VGO is basically identical. The bicyclic naphthenic acids assume the first place （about 25 m%）, while the monocyclic and tricyclic naphthenic acids take the next place. The comparison of petroleum carboxylic acids in diesel distillates and VGOs has revealed that the molecules of carboxylic acids in VGOs are not only bigger but also more complicated.

关键词： O2 class species petroleum carboxylic acids aliphatic acids naphthenic acid

CFD simulation of homogeneous reaction characteristics of dehydration of fructose to HMF in micro-channel reactors

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemical engineering 2018年第6期26卷 1340-1349页

作者： Xin Zhang Hui Liu Amar Samb Guofeng Wang State Key Laboratory of Chemical Resource engineering Beijing University of Chemical Technology Beijing 100029 China Beijing Key Laboratory of Energy Environmental Catalysis Beijing University of Chemical Technology Beijing 100029 China china tianchen engineering corporation (Beijing Branch) Beijing 100029 China

In this work the applicability of the micro-channel reactor technique to the production of promising platform chemical 5-hydroxymethyl furan(HMF) from fructose in aqueous solution is systemically investigated by performing CFD *** factors including solvents,residence time distribution of reaction mixtures,heat transfer conditions and micro-channel configurations are evaluated in terms of the reaction performance indices,i.e.,conversion of fructose,HMF selectivity and yield.A scale-up method from a single channel to a multiple channel reactor is also *** is demonstrated that:1) at the single channel scale,controlling residence times and temperature distribution of the reaction mixture within the channel is crucial for enhancing the reaction performance,while different channel configurations lead to marginal improvements;2) for the scaling-up of the reaction process,a reactor module containing 15 circular parallel channels could be used as module blocks,which can be stacked one by one to meet the required reactor performance and production *** present results show that micro-reactors are quite suitable for HMF production.

关键词： Fructose dehydration Micro-channel reactor Simulation Optimization

Interface construction of NiCo LDH/NiCoS based on the 2D ultrathin nanosheet towards oxygen evolution reaction

在线全文

学校读者我要写书评

暂无评论

Nano Research 2022年第6期15卷 4986-4995页

作者： Jiahui Li Lili Wang Haojia He Yiquan Chen Zirui Gao Na Ma Bing Wang Linlin Zheng Rulin Li Yujia Wei Junqing Xu Yao Xu Bowen Cheng Zhen Yin Ding Ma State Key Laboratory of Separation Membranes and Membrane Processes School of ChemistryTiangong UniversityTianjin 300387China School of Chemical engineering and Technology Tiangong UniversityTianjin 300387China Beijing National Laboratory for Molecular Sciences College of Chemistry and Molecular Engineering and College of Engineeringand BIC-ESATPeking UniversityBeijing 100871China College of Chemical engineering and Materials Science Tianjin University of Science and TechnologyTianjin 300457China china tianchen engineering corporation Tianjin 300400China

Carbon-free hydrogen as a promising clean energy source can be produced with electrocatalysts via water *** evolution reaction(OER)as anodic reaction determines the overall efficiency of water electrolysis due to sluggish OER ***,it’s much desirable to explore the efficient and earth-abundant transition-metal-based OER electrocatalysts with high current density and superior stability for industrial alkaline ***,we demonstrate a significant enhancement of OER kinetics with the hybrid electrocatalyst arrays in alkaline via judiciously combining earth-abundant and ultrathin NiCo-based layered double hydroxide(NiCo LDH)nanosheets with nickel cobalt sulfides(NiCoS)with a facile metal-organic framework(MOF)-template-involved surface sulfidation *** obtained NiCo LDH/NiCoS hybrid arrays exhibits an extremely low OER overpotential of 308 mV at 100 mA·cm^(−2),378 mV at 200 mA·cm^(−2)and 472 mV at 400 mA·cm^(−2)in 1 M KOH solution,respectively.A much low Tafel slope of 48 mV·dec^(−1)can be ***,with the current density from 50 to 250 mA·cm^(−2),the NiCo-LDH/NiCoS hybrid arrays can run for 25 h without any *** results demonstrate that the construction of hybrid arrays with abundant interfaces of NiCo LDH/NiCoS can facilitate OER kinetics via possible modulation of binding energy of O-containing intermediates in alkaline *** present work would pave the way for the development of lowcost and efficient OER catalysts and industrial application of water alkaline electrolyzers.

关键词： oxygen evolution reaction hybrid structure ultrathin nanosheet layered double hydroxide surface sulfidation interface of NiCo LDH/NiCoS

Correlation Analysis of Transient Heat Transfer Characteristics for Air Precooling Aggregate

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Thermal Science 2017年第2期26卷 144-152页

作者： GUO Chaohong ZENG Miao LU Fei TANG Dawei GUAN Wei LI Li FU Tingwu Institute of engineering Thermophysics Chinese Academy of Sciences Northwest engineering corporation Limited Power Construction Corporation of China

In dam works, air precooling of aggregate is a common and effective method to avoid temperature cracks in concrete structure. In order to offer a reliable design theory for the air precooling process to avoid unreasonable energy consumption, the transient heat transfer characteristics of the aggregate are intensively analyzed. The combined structure of the aggregate and the interstitial space in the hopper is treated as a porous structure, and the space-average method is used to simulate the transient heat transfer process. Simulation results show that size of the hopper and the average air velocity in the cross section have great influence on the transient heat transfer process of the aggregate, while the porosity in the range of 0.4-0.5 has little influence. Nomograms are abstracted from simulation results, and then correlations of the compared excess temperature are precisely fitted to predict the air precooling transient heat transfer process of the aggregate.

关键词： Air precooling Aggregate Transient heat transfer Nomogram

A method to refine the start-up scheme of compression and refrigeration systems in ethylene plants via dynamic simulation

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemical engineering 2016年第8期24卷 1007-1012页

作者： Shengfu Zhang Yongchen Zhao Tong Qiu Guang Song Jinsong Zhao Department of Chemical engineering Tsinghua University china Huanqiu Contracting & engineering corporation

Starting the cracking gas compressor and precooling the refrigeration system are keys to start-up of an ethylene plant and accounts for up to 50% of the total start-up time and plant flare emissions. Premature feeding of cracking furnaces can be avoided if the cracking gas compressor is started and the refrigeration system is precooled in advance using mixed gas as the start-up working medium(SWM). Start-up scenario with mixed gas as SWM could significantly reduce the emission loss and shorten the precooling time. Research shows that making appropriate start-up scheme is important not only to ensure operational safety and feasibility, but also to reduce energy consumption. In this paper, a method is proposed to select suitable start-up operational parameters of compression and refrigeration system with sufficient safe operating ranges and short precooling time. The complex interrelation among key parameters of start-up is analyzed. It is found that higher energy consumption, especially for super high-pressure steam(SS), can promote operational safety and shorten the precooling time during *** on steady-state and dynamic simulation, appropriate operating parameter ranges are determined with reasonable SS consumption. A real case study demonstrates that an appropriate start-up scheme will optimize the operation.

关键词： Start-up Ethylene plant Start-up working medium Mixed gas run Compression system

Coordination of distinctive pesticide adjuvants and atomization nozzles on droplet spectrum evolution for spatial drift reduction

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemical engineering 2024年第2期66卷 250-262页

作者： Shidong Xue Jingkun Han Xi Xi Zhong Lan Rongfu Wen Xuehu Ma State Key Laboratory of Fine Chemicals Liaoning Key Laboratory of Clean Utilization of Chemical ResourcesInstitute of Chemical EngineeringSchool of Chemical EngineeringDalian University of TechnologyDalian 16024China School of Fashion and Textiles The Hong Kong Polytechnic UniversityHong Kong 999077China china tianchen engineering corporation Tianjin 300400China School of Energy and Power engineering Dalian University of TechnologyDalian 116024China

Pesticide adjuvants,as crop protection products,have been widely used to reduce drift loss and improve utilization efficiency by regulating droplet ***,the coordinated regulation mechanisms of adjuvants and nozzles on droplet spectrum remain ***,we established the relationship between droplet spectrum evolution and liquid atomization by investigating the typical characteristics of droplet diameter distribution near the *** on this,the regulation mechanisms of distinctive pesticide adjuvants on droplet spectrum were clarified,and the corresponding drift reduction performances were quantitively evaluated by wind tunnel *** shows that the droplet diameter firstly shifts to the smaller due to the liquid sheet breakup and then prefers to increase caused by droplet *** the surface tension of sprayed liquid facilitates the uniform liquid breakup and increasing the viscosity inhibits the liquid deformation,which prolong the atomization process and effectively improve the droplet *** a result,the drift losses of flat-fan and hollow cone nozzles are reduced by about 50%after adding organosilicon and vegetable oil *** contrast,the air induction nozzle shows a superior anti-drift ability,regardless of distinctive *** findings provide insights into rational adjuvant design and nozzle selection in the field application.

关键词： Pesticide drift Spray droplets Particle size distribution Spray atomization Transport processes Adjuvants

Resilience based importance measure analysis for SoS

在线全文

学校读者我要写书评

暂无评论

Journal of Systems engineering and Electronics 2019年第5期30卷 920-930页

作者： PAN Xing WANG Huixiong YANG Yanjing ZHANG Guozhong School of Reliability and Systems engineering Beihang UniversityBeijing 100191China china Railway Signal and Communication corporation Beijing 100070China Institute of Systems engineering China State Shipbuilding CorporationBeijing 100036China

In a system of systems(SoS),resilience is an important factor in maintaining the functionality,stability,and enhancing the operation *** the perspective of resilience,this paper studies the importance of the SoS,and a resilience-based importance measure analysis is conducted to provide suggestions in the design and optimization of the structure of the *** this paper,the components of the SoS are simplified as four kinds of network nodes:sensor,decision point,influencer,and *** this networked SoS,the number of operation loops is used as the performance indicator,and an approximate algorithm,which is based on eigenvalue of the adjacency matrix,is proposed to calculate the number of operation *** order to understand the performance change of the SoS during the attack and defense process in the operations,an integral resilience model is proposed to depict the resilience of the *** different perspectives of enhancing the resilience,different measures,parameters and the corresponding algorithms for the resilience importance of components are ***,a case study on an SoS is conducted to verify the validity of the network modelling and the resiliencebased importance analysis method.

关键词： system of systems (SoS) resilience network modelling importance measure analysis operation loop

Mesh‑free semi‑quantitative variance underestimation elimination method in Monte Caro algorithm

在线全文

学校读者我要写书评

暂无评论

Nuclear Science and Techniques 2023年第1期34卷 157-171页

作者： Peng‑Fei Shen Xiao‑Dong Huo Ze‑Guang Li Zeng Shao Hai‑Feng Yang Peng Zhang Kan Wang Department of engineering Physics Tsinghua UniversityBeijing 100084China china Nuclear Power engineering corporation Beijing 100840China

The inter-cycle correlation of fission source distributions(FSDs)in the Monte Carlo power iteration process results in variance underestimation of tallied physical quantities,especially in large local *** study provides a mesh-free semiquantitative variance underestimation elimination method to obtain a credible confidence interval for the tallied *** method comprises two procedures:Estimation and *** FSD inter-cycle correlation length is estimated in the Estimation procedure using the Sliced Wasserstein distance *** batch method was then used in the elimination *** FSD inter-cycle correlation length was proved to be the optimum batch length to eliminate the variance underestimation *** exemplified this method using the OECD sphere array model and 3D PWR BEAVRS *** results showed that the average variance underestimation ratios of local tallies declined from 37 to 87%to within±5%in these models.

关键词： Monte Carlo algorithm Power iteration process Inter-cycle correlation Variance underestimation Sliced Wasserstein distance