检索结果-内蒙古大学图书馆

SSRN 2024年

作者： Sen, Palash Chen, Mengjie Bai, Bofeng State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an710049 China

Heat transfer enhancement technologies of air flow are of critical to energy conservation and emission reduction in industrial applications. This paper explores the numerical simulation analysis of 18 kinds of perforated dimple/protrusion fins. The wind speed varies within the range of 2~6m/s, and the investigation delves into the impact of different structural parameters on strengthening factor Nu/Nu0, resistance factor f/f0 and other comprehensive evaluation factor performance evaluation criteria (PEC) of perforated dimple/protrusion fins. The study specifically explores the influence of structural parameters, including intercepting perforated dimple/protrusion height (S0), aperture (D), hole structure offset (a), and the arrangement of perforated dimple/protrusion structure, on heat transfer performance. The overall heat transfer performance of the perforated dimple/protrusion fins rises with height under the same operating conditions. It first increases and then declines with the increasing aperture, and first drops and then increases with the increasing offset. The hole structure offset is better on the inflowing leeward side than on the inflowing side. The fins with both perforated dimple and perforated protrusion structures have advantages over the one with either of two structures, and the alignment arrangements are identified as the optimal configuration. © 2024, The Authors. All rights reserved.

关键词： Air

来源：评论

学校读者我要写书评

暂无评论

Calcium Looping Sorption-Enhanced Electrified Steam Methane Reforming for Efficient Hydrogen Production with Short- and Long-Duration Cooperative Energy Storage

SSRN

引用

SSRN 2024年

作者： Song, Huchao Zhang, Xinyue Lin, Xiaolong Bian, Hao Liu, Yinhe State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an710049 China

Currently, the dominant hydrogen production technology is steam methane reforming, but both the reforming reaction and the combustion for driving the reaction produce significant CO2 emissions. Sorption-enhanced methane reforming enables the in-situ removal of CO2 produced by the reforming reaction and promotes higher hydrogen yields, however, CO2 emissions from combustion cannot be avoided. Renewable electricity instead of combustion for reaction heating can eliminate combustion carbon emissions and flue gas heat loss, but its dependence on renewable electricity supply prevents continuous and stable operation. This study proposes a sorption-enhanced electrified steam methane reforming technology based on short- and long-duration cooperative energy storage and calcium looping carbon capture. This technology utilizes the CO2 adsorption and energy storage property of the absorbent to absorb CO2 in situ in the reformer and transform renewable electricity to chemical and thermal energy in the regenerator as short- duration energy storage. The energy stored in the absorbent can be used to drive the methane reforming reaction and transformed into chemical energy in hydrogen continuously as long- duration energy storage. Through First law and Second law analysis, this study has found that the novel process improves thermal efficiency by 8.5 percentage points and reduces the exergy loss of the overall process by 53.2% compared with the sorption-enhanced steam methane reforming process. Based on current fuel prices in China, the novel process is more economical than the other steam methane reforming processes simulated in this study. Sensitivity analysis has found that low electricity and high methane prices benefit the economic performance of the novel process. This study may provide a stable, efficient, and economical way of clean hydrogen energy production. © 2024, The Authors. All rights reserved.

关键词： Hydrogen production

来源：评论

学校读者我要写书评

暂无评论

High Concentration of CO and CO2 Inhibits Coal Gasification in Supercritical Water

SSRN

引用

SSRN 2024年

作者： Zhang, Rui Zhao, Shuaiqi Huang, Han Zhao, Kunpeng Bai, Bofeng State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an710049 China

Supercritical water gasification technology achieves efficient resource utilization of lignite and produces H2, CO and CO2. In this study, we experimentally investigated the impact of gas product generated from high concentration (>30 wt%) formic acid decomposition on the gasification of Tiebei lignite in the supercritical water. H2 promotes the pyrolysis of carbon structures, the increase in CO promotes CO2 generation through the water-gas shift reactions, and the enrichment of CO2 hinders gas diffusion. We found that high concentration of formic acid(H2, CO and CO2) inhibits the gasification of Tiebei lignite in the supercritical water. Compared with coal gasification in the supercritical water without formic acid, 30wt% formic acid reduces the carbon efficiency of lignite by 7.66%, and the mass conversion of coal by 3.97%. When the concentration of formic acid is 30wt% to 70wt%, the higher concentration of formic acid(H2, CO and CO2), the worse gasification performance of Tiebei lignite. © 2024, The Authors. All rights reserved.

关键词： Water gas shift

来源：评论

学校读者我要写书评

暂无评论

Experimental Investigation on Sodium Migration and Mineral Transformation in Ash Deposit During Gasification of Zhundong Coal Using a Drop Tube Furnace 9th

Experimental Investigation on Sodium Migration and Mineral T...

引用

9th International Symposium on Coal Combustion, ISCC 2019

作者： Liu, Chengchang Wang, Chang’an Wang, Chaowei Du, Yongbo Tang, Guantao Li, Guangyu Che, Defu State Key Laboratory of Multiphase Flow in Power Engineering School of Energy and Power Engineering Xi’an Jiaotong University Xi’an710049 China

ISBN: (纸本)9789811616563

Zhundong coal has attracted an ever-increasing concern due to its super-huge reserve but high content of alkali metals. Volatilized into the gaseous phase during the gasification process, alkali metals are extremely unfavorable for coal utilization. Gasification technology can promote the large-scale utilization of high-alkali coal. However, few efforts, if any, have been conducted on gasification of Zhundong coal. The present study aimed to elucidate the sodium migration and mineral transformation characteristics in coal ash deposition process under different gasification conditions, while the behavior of sodium migration and mineral transformation were further analyzed using Inductively Coupled Plasma-Atomic Emission Spectrometer (ICP-OES), X-ray diffraction (XRD) and X-ray fluorescence (XRF) techniques. In this paper, the sodium migration characteristics in gasification process under different conditions were investigated by adding three sodium salts (NaCl, Na2CO3 and Na2SO4), kaolin and diatomite into coal, respectively. The effects of ash deposition time on sodium migration and mineral transformation characteristics in ash were also explored. The experimental results showed that the addition of sodium salt could increase the sodium content in the ash to a large extent. Kaolin and diatomite could solidify alkali metals in the gaseous phase during gasification process. As the ash accumulation time increased, the minerals such as chlorine, sulphur, and iron in the gaseous phase were easily bonded to the surface of the ash and reacted to form other crystal phases. The present study can provide guidance for the utilization of Zhundong coal and benefit the development of clean coal technology. © 2022, Tsinghua University Press.

关键词： Coal

来源：评论

学校读者我要写书评

暂无评论

Numerical Simulation on Combustion Characteristics of Co-Firing Biomass Syngas and Coal in a 660 MW Utility Tower Boiler 9th

Numerical Simulation on Combustion Characteristics of Co-Fir...

引用

9th International Symposium on Coal Combustion, ISCC 2019

作者： Ma, Shihao Zhang, Yan Zhu, Zhengrong Deng, Lei Che, Defu State Key Laboratory of Multiphase Flow in Power Engineering School of Energy and Power Engineering Xi’an Jiaotong University Xi’an710049 China

ISBN: (纸本)9789811616563

Utilize the biomass energy and adopt carbon capture and storage technologies could reduce the CO2 emission effectively. Biomass gasification is an effective ways to use the biomass. Co-firing biomass syngas with pulverized coal under oxy-fuel condition in utility boiler can combine the two advantages to reduce the CO2 emission. In this paper, a new proposed combustion mechanism was used to investigate the combustion characteristics of co-firing different types biomass syngas and coal in a 660 MW double reheat tower boiler. The influence of syngas composition and oxy-fuel condition on temperature distributions and flue gas components was analyzed when total input heat of the boiler was steady. The results show that the temperature and the emission of the NO and CO2 decrease in co-firing conditions, the NO mass concentration reduced up to 10.2% in co-firing cases. Biomass syngas with higher H2 and less CO and CH4 composition contributes to lower CO2 emission and higher boiler temperature, which can improve plant performance. The oxy-fuel condition also affects the combustion characteristics to some extent. With the increase of O2 volume fraction, the temperature increases and the O2 consumption decreases. Moreover, the NO mass concentration increases in oxy-fuel combustion when co-firing biomass syngas and coal with a mixing ratio of 0.1. This study offers reference for boiler’s operation and design optimization for biomass syngas co-firing. © 2022, Tsinghua University Press.

关键词： Coal

来源：评论

学校读者我要写书评

暂无评论

Flocculation of suspended cohesive particles in Rayleigh-Bénard turbulence

引用

Physical Review Fluids 2025年第2期10卷 024305-024305页

作者： Han Huang Shuaiqi Zhao Rui Zhang Binbin Pei Kunpeng Zhao Bofeng Bai State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an 710049 China Key Laboratory of Mechanics on Disaster and Environment in Western China The Ministry of Education of China Lanzhou University Lanzhou 730000 China

We employ a four-way coupled numerical approach to investigate the dynamics of suspended cohesive particles in Rayleigh-Bénard turbulence. The Stokes drag, cohesive, and direct contact forces between primary particles are captured in detail, yielding the phenomena of flocs' aggregation, breakage, and deformation. The momentum and thermal exchange between primary particles and the fluid are considered based on the Source-in-Cell method. We found that the initial increase of the average floc size indicates a temporary flocculation phase, which is followed by an equilibrium phase where the average floc size becomes stable, reflecting the balance between aggregation and breakage. Different from the traditional perspective, which attributed the local accumulation of particles to their gravity, we found that the suspended particles still tend to accumulate in the bottom hot boundary layer region. This accumulation is primarily driven by the temperature-induced variation in aggregation strength and the nonuniform spatial distribution of floc inertia. Additionally, the stronger cohesion yields a reduction in momentum intensity of the thermal plumes, primarily due to the more pronounced weakening of fluid momentum by the larger flocs.

关键词： Momentum

来源：评论

学校读者我要写书评

暂无评论

Simulation Investigation on NOx Emission Characteristics and Mechanisms During Co-combustion of Fossil Fuels with Different Fuel-Nitrogen Distributions via CHEMKIN 9th

Simulation Investigation on NOx Emission Characteristics and...

引用

9th International Symposium on Coal Combustion, ISCC 2019

作者： Wang, Chaowei Wang, Chang’an Zhao, Lin Yuan, Maobo Wang, Pengqian Du, Yongbo Che, Defu State Key Laboratory of Multiphase Flow in Power Engineering School of Energy and Power Engineering Xi’an Jiaotong University Xi’an710049 China

ISBN: (纸本)9789811616563

There are over 100 million tons of semi-coke produced in China every year, and use of the semi-coke in utility coal-fired boilers is a promising approach. In this paper, a blending model of semi-coke and bituminous coal was established via CHEMKIN. The NOx emission was investigated by analyses of sensitivity and production rate, while the effects of stoichiometric ratio of main combustion zone, blending ratio, and combustion temperature on migration of fuel nitrogen were further elucidated. The simulation results showed that the conversion ratio of NOx increased monotonically with an increase in the stoichiometric ratio of main combustion zone. The temperature of plug flow reactor (PFR) I exhibited a significant effect on NOx emission, but other reactors had limited influences. The NOx conversion ratio was enlarged with the increase of semi-coke blending ratio. The influence of blending proportion on NOx emission was significant when the stoichiometric ratio of main combustion zone was small. Compared with high blending ratio, the main reactions with low blending ratio had stronger inhibitory effect on the formation of NO. The present study was of guiding significance for reducing NOx emission in the utility boilers co-firing semi-coke. © 2022, Tsinghua University Press.

关键词： Sensitivity analysis

来源：评论

学校读者我要写书评

暂无评论

Graph neural network-driven prediction of high-performance CO_(2)reduction catalysts based on Cu-based high-entropy alloys

引用

Chinese Journal of Catalysis 2025年第4期71卷 197-207页

作者： Zihao Jiao Chengyi Zhang Ya Liu Liejin Guo Ziyun Wang International Research Center for Renewable Energy State Key Laboratory of Multiphase Flow in Power EngineeringXi’an Jiaotong UniversityShaanxi 710049China School of Chemical Sciences University of AucklandAuckland 1010New Zealand

High-entropy alloy(HEA)offer tunable composition and surface structures,enabling the creation of novel active sites that enhance catalytic performance in renewable energy ***,the inherent surface complexity and tendency for elemental segregation,which results in discrepancies between bulk and surface compositions,pose challenges for direct investigation via density functional *** address this,Monte Carlo simulations combined with molecular dynamics were employed to model surface segregation across a broad range of elements,including Cu,Ag,Au,Pt,Pd,and *** analysis revealed a trend in surface segregation propensity following the order Ag>Au>Al>Cu>Pd>*** capture the correlation between surface site characteristics and the free energy of multi-dentate CO_(2)reduction intermediates,a graph neural network was designed,where adsorbates were transformed into pseudo-atoms at their centers of *** model achieved mean absolute errors of 0.08–0.15 eV for the free energies of C_(2)intermediates,enabling precise site activity *** indicated that increasing the concentration of Cu,Ag,and Al significantly boosts activity for CO and C_(2)formation,whereas Au,Pd,and Pt exhibit negative *** screening stable composition space,promising HEA bulk compositions for CO,HCOOH,and C_(2)products were predicted,offering superior catalytic activity compared to pure Cu catalysts.

关键词： Density functional theory Machine learning CO_(2)reduction High entropy alloys Graph neural network

来源：评论

学校读者我要写书评

暂无评论

Analysis of Different Control Strategies Considering Individual Regulation of Heat User 3

Analysis of Different Control Strategies Considering Individ...

引用

3rd International Conference on Electrical Engineering and Mechatronics Technology, ICEEMT 2023

作者： Xun, Zhiwei Wang, Huijie Wang, Liyuan Yang, Long Gao, Yunfang Liu, Ming Guoneng Jinjie Energy Co. Ltd Yulin China Xi'an Jiaotong University Xi'an China Xi'an Jiaotong University State Key Laboratory of Multiphase Flow in Power Engineering Xi'an China

ISBN: (纸本)9798350303698

In the process of outdoor temperature change, it is beneficial to improve the comfort of thermal users to formulate adjustment and control strategies according to the actual needs of each user. In this paper, different adjustment modes are established according to the thermal comfort of users, and the control strategies of rising and cooling within 0, 30 and 60 minutes are proposed, and the indoor temperature control effect and heating energy consumption of each adjustment mode under different control strategies are analyzed. The results show that: in different modes, when the rise and cooling time increase, compared with the design room temperature, the indoor temperature difference under the control mode is smaller, but the time needed to reach stability is longer. At the same time, the total heat load is unchanged, but the total pump work decreases. © 2023 IEEE.

关键词： Energy utilization

来源：评论

学校读者我要写书评

暂无评论

Chalcogen heteroatoms doped nickel-nitrogen-carbon single-atom catalysts with asymmetric coordination for efficient electrochemical CO_(2) reduction

引用

Chinese Journal of Catalysis 2024年第9期64卷 54-65页

作者： Jialin Wang Kaini Zhang Ta Thi Thuy Ng Yiqing Wang Yuchuan Shi Daixing Wei Chung-Li Dong Shaohua Shen International Research Center for Renewable Energy State Key Laboratory of Multiphase Flow in Power EngineeringXi'an Jiaotong UniversityXi'an 710049ShaanxiChina Department of Physics Tamkang UniversityNew Taipei City 25137TaiwanChina

The electronic configuration of central metal atoms in single-atom catalysts(SACs)is pivotal in electrochemical CO_(2) reduction reaction(eCO_(2)RR).Herein,chalcogen heteroatoms(e.g.,S,Se,and Te)were incorporated into the symmetric nickel-nitrogen-carbon(Ni-N_(4)-C)configuration to obtain Ni-X-N_(3)-C(X:S,Se,and Te)SACs with asymmetric coordination presented for central Ni *** these obtained Ni-X-N_(3)-C(X:S,Se,and Te)SACs,Ni-Se-N_(3)-C exhibited superior eCO_(2)RR activity,with CO selectivity reaching~98% at-0.70 V versus reversible hydrogen electrode(RHE).The Zn-CO_(2) battery integrated with Ni-Se-N_(3)-C as cathode and Zn foil as anode achieved a peak power density of 1.82 mW cm^(-2) and maintained remarkable rechargeable stability over 20 ***-situ spectral investigations and theoretical calculations demonstrated that the chalcogen heteroatoms doped into the Ni-N_(4)-C configuration would break coordination symmetry and trigger charge redistribution,and then regulate the intermediate behaviors and thermodynamic reaction pathways for eCO_(2)***,for Ni-Se-N_(3)-C,the introduced Se atoms could significantly raise the d-band center of central Ni atoms and thus remarkably lower the energy barrier for the rate-determining step of ^(*)COOH formation,contributing to the promising eCO_(2)RR performance for high selectivity CO production by competing with hydrogen evolution reaction.

关键词： Electrochemical CO_(2) reduction reaction Chalcogen heteroatoms Single-atom catalysts Asymmetric coordination CO production

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：