检索结果-内蒙古大学图书馆

Gas and Liquid flow Rate Measurement in Wet Gas Based on Differential Pressure Signals

Jixie Gongcheng Xuebao/Journal of Mechanical engineering 2017年第24期53卷 55-62页

作者： Bai, Bofeng Zheng, Xuebo Qiu, Lu State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an710049 China Scientific Information Division Xinjiang Oilfield Company Karamay834000 China

The basic characteristics of differential pressure signals and the limitation of flow rate metering methods based on differential pressure are studied analytically and experimentally. Through the investigation into differential pressure signals of orifice plate and V-cone, it is found that the two-phase differential pressure is mainly caused by gas phase and is slightly affected by the liquid phase. In the case of low liquid hold up, the frictional pressure drop can be decreased due to the presence of the thin liquid film on the wall, resulting in that the two-phase differential pressure, pressure loss and pressure loss ratio decrease at first and then increase as the liquid hold up increases. The fluctuation of the differential pressure is stochastic, causing the fluctuation characteristic parameters, such as the standard deviation, having the properties of poor stability and repeatability. This makes it difficult to be applied to industrial wet gas metering. The error propagation analysis demonstrates that the prediction error of liquid phase flow rate is much larger than that of the gas phase, which is a universal phenomenon of metering methods based on over-reading correlations. Finally, we recommend that for wet gas with high gas void fraction, the liquid flow rate should be measured independently. The non-monotonicity of the pressure loss ratio needs to be concerned if it is chosen as the characteristic parameter. Parameters with poor repeatability, such as standard deviation, are not recommended for wet gas metering. © 2017 Journal of Mechanical engineering.

关键词： flow rate

来源：评论

学校读者我要写书评

暂无评论

Investigation on Correlations between Chemical Properties of High-alkali Solid Fuels

引用

Energy Procedia 2017年 142卷 1040-1044页

作者： Chang’an Wang Xin Zhu Jun Song Xuan Liu Qiang Lv Defu Che State Key Laboratory of Multiphase Flow in Power Engineering School of Energy and Power Engineering Xi’an Jiaotong University Xi’an 710049 China Ningxia Electric Power Research Institute Yinchuan 750002 China

The ash-related issues due to the high-alkali characteristic are still unresolved during utilization of biomass and Zhundong coal. Here, the correlations of several chemical properties of high-alkali solid fuels were investigated. The distributions of ash compositions in various biomass exhibit obvious diversity, while the distribution of K 2 O content within wheat and corn straws are the most scattered. The ash content in biomass shows a decrease tendency with the increase of carbon content. Zhundong coals generally have medium but close ash fusion points despite of quite different ash compositions sometimes.

关键词： high alkali chemical property Zhundong coal biomass ternary distribution

来源：评论

学校读者我要写书评

暂无评论

Computational fluid dynamics simulation of hydrodynamics in the riser of an external loop airlift reactor

引用

Particuology 2016年第4期14卷 95-101页

作者： Xuedong Jiang Ning Yang Bolun Yang Department of Chemical Engineering State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an 710049 China Center for Mesoscience and State Key Laboratory of Multiphase Complex Systems Institute of Process Engineering Chinese Academy of Sciences Beijing 100190 China

Local hydrodynamics in the riser of an external loop airlift reactor （EL-ALR） are identified and the performances of three drag models are evaluated in computational fluid dynamics simulation. The simulation results show that the Schiller-Naumann drag model underestimated the local gas holdup at lower superficial gas velocity whereas the Tomiyama drag model overestimated that at higher superficial gas velocity. By contrast, the dual-bubble-size （DBS）-local drag model gave more reasonable radial and axial distri-butions of gas holdup in all cases. The reason is that the DBS-local drag model gave correct values of the lumped parameter, i,e., the ratio of the drag coefficient to bubble diameter, for varying operating conditions and radial positions. This ratio is reasonably expected to decrease with increasing superficial gas velocity and be smaller in the center and larger near the wall. Only the DBS-local drag model correctly reproduced these trends. The radial profiles of the axial velocity of the liquid and gas predicted by the DBS-local model also agreed well with experimental data.

关键词： Computational fluid dynamics External loop airlift reactor Drag model Gas holdup Mnltiscale Mesoscale

来源：评论

学校读者我要写书评

暂无评论

Layered sphere-shaped TiO_2 capped with gold nanoparticles on structural defects and their catalysis of formaldehyde oxidation

引用

Journal of Environmental Sciences 2016年第1期28卷 77-85页

作者： Chunyan Ma Guanglong Pang Guangzhi He Yang Li Chi He Zhengping Hao Department of Environmental Nano-materials Research Center for Eco-Environmental Sciences Chinese Academy of Sciences Department of Environmental Science and Engineering State Key Laboratory of Multiphase Flow in Power EngineeringSchool of Energy and Power Engineering Xi'an Jiaotong University

We describe here a one-step method for the synthesis of Au/TiO2 nanosphere materials,which were formed by layered deposition of multiple anatase TiO2 *** Au nanoparticles were stabilized by structural defects in each TiO2 nanosheet,including crystal steps and edges,thereby fixing the Au-TiO2 perimeter *** transfer occurred along the gaps between these TiO2 nanosheet layers and in contact with catalytically active sites at the Au-TiO2 *** doped Au induced the formation of oxygen vacancies in the Au-TiO2 *** vacancies are essential for generating active oxygen species（-＊O^-） on the TiO2 surface and Ti^3＋ ions in bulk *** ions can then form Ti^3＋-O^--Ti^4＋species,which are known to enhance the catalytic activity of formaldehyde（HCHO） *** studies on structural and oxygen vacancy defects in Au/TiO2 samples provide a theoretical foundation for the catalytic mechanism of HCHO oxidation on oxide-supported Au materials.

关键词： Layered Au/TiO2 nanospheres Structural defects Oxygen vacancy defects Reaction mechanism Formaldehyde oxidation

来源：评论

学校读者我要写书评

暂无评论

Integration of Organic Rankine Cycle with Lignite Flue Gas Pre-drying for Waste Heat and Water Recovery from Dryer Exhaust Gas: Thermodynamic and Economic Analysis

引用

Energy Procedia 2017年 105卷 1614-1621页

作者： Xiaoqu Han Sotirios Karellas Ming Liu Konstantinos Braimakis Weixiong Chen Junjie Yan Emmanuel Kakaras State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an 710049 China Laboratory of Steam Boilers and Thermal Plants National Technical University of Athens Athens 15780 Greece

The flue gas pre-drying of lignite produces a moisture rich dryer exhaust gas which can be further cooled to recover the waste heat and water vapor. An environmental friendly power system is investigated in the present work, which integrates the lignite flue gas pre-drying system with an organic Rankine cycle (ORC) to utilize the waste heat to generate power and capture the condensed water. Simulation models of the integrated system are developed, incorporating thermodynamic and economic evaluation indicators. The optimal energy and exergy efficiencies of the ORC system are calculated to be 3.10% and 24.57%, respectively, for an evaporation temperature of 51 °C when R245fa is used as the working fluid. Accordingly, the ORC power output is 3.61 MW and the absolute plant efficiency improvement is 0.27% points. Moreover, 55.17% of the water vapor can be recovered. The economic performance significantly relies on the specific investment cost of ORC and the electricity selling price. Typically, the break-even points of the specific investment cost are 2300 €/kW and 3700 €/kW when electricity selling prices are 0.05 €/kWh and 0.08 €/kWh, respectively.

关键词： Lignite Flue gas pre-drying Waste heat recovery Organic Rankine cycle

来源：评论

学校读者我要写书评

暂无评论

Product-based Carbon Constraint Energy Planning with pinch analysis for sustainable methanol industry in China

引用

Chemical engineering Transactions 2017年 61卷 103-108页

作者： Qin, Zhen Tang, Kai Wu, Xiaomei Yu, Yunsong Zhang, Zaoxiao School of Chemical Engineering and Technology Xi'an Jiaotong University Xi'an710049 China State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an710049 China

For the purpose of greenhouse gas control in chemical industries, the industrial structure adjustment and lowcarbon technology retrofit are the alternatives for policymakers and plants to simultaneously meet the energy demand and carbon emission limit. Considering the various technological sources and predictable product demand in methanol production industries, this paper presents the method of Product-based Carbon Constraint Energy Planning (PCEP) combined with improved GM(1,1) model to analyse the practical interaction between energy demand and carbon emission for methanol industry in 2020 in China. The results show that without any emission reduction measures, the total carbon emissions of methanol industry in 2020 would be 4.84 times larger than that of 2011. By enhancing the methanol production of biomass routing and conducting the project of CO2 capture and storage (CCS) in all coal-to-methanol plants, the total carbon emissions would be 36.01 % less than the given carbon constraint. Besides, at least 65 % of coal-to-methanol plants should be retrofitted with CCS on the consideration of the current challenges of biofuel development in order to meet the carbon constraint. The energy structure of China and the inherent property with high carbon content in coal determine that the coal-to-methanol routing contributes the most of methanol supply but also the maximum carbon emissions in the methanol industry, even if policymakers and plants take measures to adjust the industrial structure and retrofit the existing plants with low-carbon technology. Copyright © 2017, AIDIC Servizi S.r.l.

关键词： Chemical industry

来源：评论

学校读者我要写书评

暂无评论

Adsorption Characteristics of Sulfuric Acid Mist on Fly Ash in Low-low temperature Flue Gas System

引用

Energy Procedia 2017年 142卷 3307-3312页

作者： Yubo Zhang Yu Yan Jianhua Liu Qingwen Qi Lei Deng Defu Che Xi’an Thermal Power Research Institute Co. Ltd. Xi’an 710032 China State Key Laboratory of Multiphase Flow in Power Engineering School of Energy and Power Engineering Xi’an Jiaotong University Xi’an 710049 China Ningxia Electric Power Research Institute Ningxia 750002 China

Low-low temperature flue gas system which also called MHI high efficiency system developed by Mitsubishi Corporation has gained comprehensive attention in Japan, European countries and American. However, the applications of this system in China are facing several sever problems about corrosion and ash fouling. This paper focuses on the adsorption characteristics of sulfuric acid mist on fly ash during the flue gas cooling process in the exchanger before the electrostatic precipitator. The experimental results indicate that there is an optimum adsorption temperature for the adsorption of sulfuric acid mist, and this temperature is about 30 ℃ lower than the acid dew point. The process of adsorption is mainly dominated by chemical reactions rather than physical reactions, and the alkali metals (Na, K) and alkaline earth metals (Mg, Ca) are the main factors which influence the chemical reaction rate, especially the Na element. Besides, with the D/S increasing, the adsorption efficiency increases and it is independent of the adsorption temperature. Ash particle size also has large influence on the adsorption efficiency, the smaller the particle size is, the larger the adsorption efficiency is. And when the flue gas speed rose, gas residence time correspondingly reduced and the adsorption efficiency dropped. However, since gas residence time is short in engineering applications, the influence of gas residence time is quite moderate. Furthermore, the adsorption of the sulfuric acid mist will cause a significant agglomeration between ash particles, and it has great significance to the removal of PM.

关键词： Low-low temperature flue gas system sulfuric acid mist adsorption characteristics

来源：评论

学校读者我要写书评

暂无评论

[email protected] 2 O 4 fiber-in-tube mesoporous nanostructure: Formation mechanism and high electrochemical performance as an anode for lithium-ion batteries

引用

Journal of Alloys and Compounds 2017年 693卷 110-117页

作者： Jianan Wang Guorui Yang Ling Wang Wei Yan Wei Wei Department of Environmental Science and Engineering State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an 710049 China Department of Applied Chemistry School of Science Xi'an Jiaotong University 710049 China

In this paper, [email protected] 2 O 4 with a fiber-in-tube mesoporous nanostructure has been fabricated via a one-step single-spinneret electrospinning technique. This unique nanostructure is made of an outer spinel CoFe 2 O 4 tube and a loose inner fiber composed of the residual carbonaceous materials and metal precursors. The nanostructure's properties, such as morphology, components, structures and thermal stability, are characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-Ray diffraction (XRD), thermogravimetric analysis (TGA), Brunauer, Emmett and Teller type specific area (S BET ) determination, X-ray photoelectron spectroscopy (XPS) and inductively coupled plasma-atomic emission spectrometry (ICP-AES). As an anode material for lithium-ion batteries, the [email protected] 2 O 4 composite (6.25 wt% carbon content) exhibits a high reversible capacity of 740 mA h g −1 after over 200 cycles at the current density of 200 mA g −1 with excellent cycling stability, which is attributed to its one dimensional continuous fiber-in-tube mesoporous morphology, as well as its stable structure benefiting from the existence of carbonaceous yolk. In addition, pure CoFe 2 O 4 nanotubes can also be obtained by sequentially agitating this product in water, which provides more potential applications of CoFe 2 O 4 .

关键词： Electrospinning [email protected] 2 O 4 Fiber-in-tube Mesoporous nanostructure Li-ion batteries

来源：评论

学校读者我要写书评

暂无评论

Experimental study on thermal performance of a water/steam cavity receiver with solar simulator

引用

Energy Procedia 2017年 142卷 265-270页

作者： Zhenjie Wan Mumtaz A. Qaisrani Xuancheng Du Jinjia Wei Jiabin Fang Jian Zhang State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an 710049 People’s Republic of China School of Chemical Engineering and Technology Xi’an Jiaotong University Xi’an 710049 People’s Republic of China

The performance of cavity receiver plays a fatal role in light-heat conversion process in a concentrating solar power (CSP) plant. In our present work, an experimental platform is designed and built, in which a solar simulator consisting of seven mutually independent xenon lamp units is used for supplying the solar energy needed. The cold start-up and steady state performance of the cavity receiver were studied under 0.5MPa. The results show that for a certain cavity structure, temperatures on boiling panels and thus the heat loss can be affected not merely by the heat flux, other parameters can influence the temperature of absorbing surfaces, such as the heat transfer in the boiling tubes, fluid flow states and the wind effect, so the temperature distribution is highly non-uniform on boiling panels. However, the temperatures of passive surfaces depend greatly on the input solar energy, thus the heat losses of the passive surfaces will vary with the input energy. Overheat occurs if a high heat flux doesn’t have a sufficient heat transfer inside boiling tubes internal. The stagnation zone does exist in the cavity and its boundary varies with a different input energy, thus the convective heat loss can be affected. The cavity receiver thermal efficiency is 72.92% under 0.5MPa, may be the reason behind this low efficiency is the strong cooling wind of the solar simulator.

关键词： Solar energy central cavity receiver start-up thermal performance solar simulator thermal efficiency

来源：评论

学校读者我要写书评

暂无评论

Adsorption and Agglomeration Characteristics of Ash Particles after Reducing Flue Gas Temperature below the Acid Dew Point

引用

Energy Procedia 2017年 142卷 3301-3306页

作者： Yu Yan Ke Sun Yun Sun Yubo Zhang Junwen Guo Lei Deng Defu Che State Key Laboratory of Multiphase Flow in Power Engineering School of Energy and Power Engineering Xi’an Jiaotong University Xi’an 710049 China Huadian Electric Power Research Institute Hangzhou 310030 China Ningxia Electric Power Research Institute Ningxia 750002 China Xi’an Thermal Power Research Institute Co. Ltd. Xi’an 710054 China

In order to develop suitable low-low temperature flue gas system for China and determine its operation parameters, the adsorption characteristics of ash particles for sulfuric acid mist need to be investigated, as well as the adhesion characteristics of ash particles after the adsorption. In this paper, experiments were conducted on a laboratory-scale fixed bed adsorption reaction system. The adsorption characteristic curves of different particle sizes and adsorption temperature were obtained. The results show that adsorption temperature has a larger influence on the adsorption process compared with particle size. And there exists an adsorption limit in the adsorption process. In addition, the ultimate D/S (D p /S p ) of ash particle is defined, which means the ratio of ash particle weight (mg) to adsorbed H 2 SO 4 weight (mg) when ash particle reaches the adsorption limit. It is an inherent attribute of ash particle, only influenced by the particle constituents and sizes, representing the ultimate adsorption capacity of ash particle for sulfuric acid. The experiment results show that the chemical constituents of ash are the main determinate factors of adsorption limit and the D p /S p . And the D p /S p could be used cooperatively with D/S when people design the parameters of low-low temperature flue gas system for different types of coal. Furthermore, there was a significant agglomeration phenomenon between ash particles after the adsorption reaction, and it can increase the average size of particles which is conducive to the removal of PM.

关键词： Low-low temperature flue gas system sulfuric acid mist adsorption characteristics agglomeration Characteristics

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：