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Development and application of a coal combustion life cycle on-line monitoring system

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Energy engineering: Journal of the Association of Energy engineering 2015年第1期112卷 28-46页

作者： Liu, Haiyu Tan, Houzhang Xiong, Xiaohe Ma, Lin Miao, Yang Xu, Tongmo Taiyuan University of Technology 030024 China Xi'an Jiaotong University Xi'an710049 China Electric Power Research Institute Co. Ltd Beijing100069 China School of Process Environmental and Materials Engineering Centre for Computational Fluid Dynamics University of Leeds LS2 9JT United Kingdom State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an710049 China

In China, coal quality fluctuates and deviates greatly from the original design in many large-scale coal-fired power plants. To maintain a secure level and combustion efficiency, a "coal combustion life cycle online monitoring system" (CLMS) has been developed and installed on a 215MW boiler in China. Ten temperature detectors have been installed at the heights of three-layer burners along the furnace. To improve the accuracy of measuring unburnt carbon in fly ash, an adjustable microwave test facility was established. An on-line measurement device for unburnt carbon in ash has been newly developed and attached to the convection flue gas pass. To optimize combustion processes, a real-time neural network prediction model for coal calorific value has been developed. By calculating and analyzing the data in computer workstations, safety evaluation of burner ignition, economic analysis and energy loss analysis can be obtained in real time. As for fluctuation in coal quality, application of the system has improved boiler efficiency more than 1.0%, and reduced NOx by 10-15%. © Copyright Association of Energy Engineers (AEE).

关键词： Life cycle

Influence of dolomite additive on the ash fusion and potassium fixation characteristics of rice straw

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Ranliao Huaxue Xuebao/Journal of Fuel Chemistry and Technology 2020年第7期48卷 795-803页

作者： Yu, Zhi-Hao Jin, Jing Zhang, Rui-Pu Zhao, Bing Zhu, Yi-Zhou Wang, Guang-Xu School of Energy and Power Engineering University of Shanghai for Science and Technology Shanghai200093 China Shanghai Key Laboratory of Multiphase Flow and Heat Transfer in Power Engineering Shanghai200093 China

The influence of dolomite as an additive on the slagging and potassium fixation characteristics of rice straw upon burning was investigated in a tube furnace;the slagging mechanism as well as the interaction between the rice straw ash and dolomite were explored by using the inductively coupled plasma optical emission spectrometry (ICP-OES) and X-ray diffraction (XRD). The results show that the slagging characteristics of rice straw are significantly influenced by adding 5% dolomite. Dolomite can greatly improve the potassium fixation ability, especially at 900-1000℃;moreover, the Mg and Ca elements rich in dolomite can react with SiO2 in the rice straw ash, forming high-melting silicate minerals including diopside, monticellite and merwinite. © 2020, Science Press. All right reserved.

关键词： Dolomite

Characterization of High-Performance Nanostructured Wick for Heat Pipes

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SSRN 2023年

作者： Sun, Qishi Han, Ruiyu Guo, Kailun Wang, Chenglong Zhang, Jing He, Xiaoqiang Qiu, Suizheng Su, Guanghui Tian, Wenxi Department of Nuclear Science and Technology State Key Lab. of Multiphase Flow in Power Engineering Shaanxi Key Lab. of Advanced Nuclear Energy and Technology Xi’an Jiaotong University Xi’an710049 China Key Lab. of Nuclear Reactor System Design Technology China Nuclear Power Research and Design Institute Chengdu610213 China

To investigate the best performance wick forms to support the design and fabrication of high-performance heat pipes, in this paper, two kinds of nanostructured wick were prepared by the oxidation-reduction method. The effect of surface nanostructure on the wick performance was investigated by comparing the surface characteristics, capillary properties, permeability, and evaporation properties. The result shows that the nanostructured wick presented excellent super hydrophilic properties. A liquid-lift visualization experimental method for measuring the capillary performance factor M was proposed, and it was verified to be correct by the separation effect of the capillary pumping experiment under a vacuum environment. With the increasing oxidized degree, the densification of nanoparticles on the wick surface increased the capillary performance factor M from 8.68 μm to 13.81 μm, with a maximum enhancement of 59.1%. The effective capillary radius decreased from 4.70×10-5 m to 4.01×10-5 m, with a maximum reduction of 14.9%. The permeability increased from 4.33×10-10 m2 to 5.83×10-10 m2, with a maximum enhancement of 34.7%. The increase in porosity made the effective capillary radius dominate the competition for permeability, and the capillary performance factor decreased by 17.1%. The thermal resistance of the wick decreased with the enhancement of the capillary performance factor, which fell from 2.03×10-3 m2·K/W to 1.26×10-3 m2·K/W. The current study provides a reference for the future design and preparation of high-performance heat pipe wicks. © 2023, The Authors. All rights reserved.

关键词： Heat resistance

Kinetic Characteristics of Passivation Behavior in OFP-Cu and OF-Cu

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SSRN 2024年

作者： Ning, Zhiyuan Wen, Du Zhou, Qulan Li, Na Macdonald, Digby D. State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an710049 China Departments of Nuclear Engineering and Materials Science and Engineering University of California at Berkeley BerkeleyCA94720 United States Industrial Process and Energy Systems Engineering Ećole Polytechnique Fédérale de Lausanne EPFL SionCH-1951 Switzerland

This research presents a comprehensive comparative analysis of the passivation kinetics of OFP-Cu and OF-Cu in simulated repository electrolyte. The study employs a range of techniques, including potentiodynamic polarization, multi-step potentiostatic polarization, electrochemical impedance spectroscopy, and Mott-Schottky analysis, to explore the intricacies of corrosion behavior. The Point Defect Model (PDM) is used to interpret the steady-state physicochemical processes. Utilizing the results of PDM optimization, defect distribution diagrams within the passivation film were constructed, shedding light on the pivotal transition from p-type to n-type semiconductor properties of the film. The study concludes with an interpretation of the experimental data, highlighting the enhancement of copper's corrosion resistance due to phosphorus doping, as elucidated by the Solute-Vacancy Interaction Model. © 2024, The Authors. All rights reserved.

关键词： Copper corrosion

A Thermal Calculation Model for Tubular Condensing Heat Exchanger

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SSRN 2023年

作者： Han, Lei Yang, Kaixuan Yang, Jiahui Li, Ruiyu Li, Yuhang 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 Shanghai Power Equipment Research Institute Co. Ltd. Shanghai200240 China Shunde Institute of Inspection Guangdong Institute of Special Equipment Inspection and Research Foshan528300 China Xi’an Thermal Power Research Institute Co. Ltd. Xi’an710032 China

The condensing heat exchanger is commonly applied in various heat exchange systems. It can efficiently recover moisture and heat from the flue gas that contains water vapor. However, the convective-condensation heat transfer process is so complicated that no mature thermal calculation model is available. This study develops a thermal calculation model for the widely employed tubular condensing heat exchanger in industry. To characterize the degree of the heat and mass transfer, this study introduces two parameters, namely the sensible and latent heat transfer efficiencies of fin. The thermal calculations are conducted for the condensing heat exchangers reported in the literature to verify the proposed model by comparing it with the experimental data. The results show that the absolute error of the calculated sensible and latent heat transfer efficiencies is 0.0365 and 0.0268, respectively. A maximum difference of 5.2 K has been acquired between the measured and calculated values of the outlet temperature. The relative error of the condensate water flowrate is mostly within ±5.0% and ±10.0% under the bare-tube and finned-tube conditions, respectively, with a maximum deviation of 0.7 and 1.4 kg h-1. This study provides a general model for designing and optimizing various tubular condensing heat exchangers accurately. © 2023, The Authors. All rights reserved.

关键词： Mass transfer

Multi-Objective Optimization Design of a Solar-powered Integrated Multi-Generation System Based On Combined Sco 2 Brayton Cycle and Orc Using Machine Learning Approach

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SSRN 2024年

作者： Zhang, Junyi Wang, Jiangfeng Liu, Wenxing Hu, Bin Lou, Juwei Zhao, Pan Institute of Turbomachinery State Key Laboratory of Multiphase Flow in Power Engineering School of Energy and Power Engineering Xi’an Jiaotong University Shaanxi Xi’an710049 China Nuclear Power Institute of China No. 328 Section 1 Changshun Avenue Sichuan Chengdu610213 China DongFang Electric Engineering& Consulting Co. Ltd 18 Xixin Avenue High-tech West Zone Sichuan Chengdu611731 China

With the rapid development of technology and the accelerated degradation of the global environment, there is an urgent need to find a clean and efficient energy solution to replace traditional fossil fuels for energy production. Additionally, this solution should also meet the growing demand for various energy products for energy user. In particular for remote areas such as islands, coastal regions and deserts which are far from the power grid, regular resources such as power, freshwater, and cooling are all scarce. Therefore, integrating freshwater and cooling subsystems into the power generation system to create a multi-generation system can facilitate achieving energy self-sufficiency in remote regions. This paper proposes an integrated multi-generation system powered by a solar power tower (SPT) according to the principle of cascading energy utilization, which includes a supercritical CO2 (SCO2) Brayton cycle, an Organic Rankine cycle (ORC), an ejector refrigeration cycle (ERC), and a reverse osmosis (RO) unit. A mathematical model is established to analyze the system performance from the perspectives of energy, exergy and economics. Different machine learning algorithms including back propagation neural network (BPNN), support vector regression (SVR), random forest (RF) are used to develop prediction models of the system performance. By comparing and analyzing the predictive performance of different machine learning models, the optimal machine learning model is obtained as a surrogate model for the thermodynamic model of the proposed system to accelerate the optimization process. The results show that the BPNN model demonstrates the highest predictive accuracy and the lowest relative error fluctuation, maintaining a relative error of less than 1% for over 97.5% of the data in the testing set. When comparing the multi-objective optimization results of the BPNN model with those of the thermodynamic model from multiple perspectives, it can be observed that the res

关键词： Neural network models

Zif-8 Loaded Ag/Zno Electrospun Nanofibers Enabling High-Performance H2 Gas Sensing for Battery Safety Early Warning

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SSRN 2024年

作者： Wang, Ze Zhu, Lei Zhang, Jiaxin Wang, Jingzhao Cui, Xiangming Chen, Xin Liu, Wenbiao Ma, Hang Wang, Jianan Yan, Wei Department of Environmental Science and Engineering State Key Laboratory of Multiphase Flow in Power Engineering School of Energy and Power Engineering Xi’an Jiaotong University 28 Xianning West Road Xi’an710049 China School of Physics and Electrical Engineering Weinan Normal University Chaoyang Street Weinan714099 China Center of Research & Development Yunnan Yuntianhua Co. LTD 1417 Dianchi Road Kunming650228 China

Safety issues triggered by battery thermal runaway have become the most crucial obstacle to the future development of the high-energy-density energy storage systems. As hydrogen (H2) will be inevitably generated along with heat release caused by the side reactions in the early stages of battery thermal runaway, rapid monitoring of trace H2 is considered as an effective measure enabling the battery safety early warning. Herein, to develop high-performance H2 sensing materials to monitor of low-concentration H2 leakage, ZIF-8 loaded Ag/ZnO electrospun nanofibers (ZAZ NFs) were designed by electrospinning and self-sacrificial template methods. Benefiting from all the enrichment and sieving effects of ZIF-8 shell, the catalytic and sensitization effects of Ag and abundant active sites provided by Ag and ZIF-8 loading, the ZAZ sensor enables ppb-level limit of detection toward H2, fast response (9 s), high selectivity and excellent humidity resistance (36.1 to 100 ppm H2 at 95% RH). Furthermore, this ZAZ sensor also enabled the safety early warning (67.79 s before battery bulge) for practical pouch lithium cells, highlighting its great application potential in future advanced battery safety management system. © 2024, The Authors. All rights reserved.

关键词： Organometallics

Investigations on affinity law under gas–liquid conditions in multistage radial and mixed-flow multiphase pumps

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International Journal of Fluid Engineering

International Journal of Fluid engineering 2024年第1期1卷 56-70页

作者： Liang Chang Chenyu Yang Xiaobin Su Xiaoyu Dai Qiang Xu Liejin Guo State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong UniversityXi’an 710049China

Affinity laws have been widely used in pump design and simulation under high-temperature and corrosive *** applying such laws,it is possible to shorten development cycles and reduce test ***,current applications of affinity laws are still limited to liquid *** this paper,expressions for affinity laws and their applicability are investigated for multistage radial and mixed-flow multiphase pumps under gas–liquid conditions.A high-pressure(30 MPa)gas–liquid experimental platform is constructed,and three-stage and 25-stage radial pumps and a 15-stage mixed-flow pump are investigated,with specific speeds of 107 and *** gas compressibility taken into account,the gas–liquid two-phase flow rate,head,and power,and the corresponding dimensionless hydraulic coefficients,are defined for multiphase *** deterioration of gas–liquid pressurization performance is found to be divided into three processes with different dynamic mechanisms,corresponding to three flow *** inlet gas volume fraction of pump is used to judge dynamic *** the same inlet gas volume fractionsλ_(1)=λ_(2),when the gas–liquid flows in two pumps have the same flow pattern,dynamic similarity will be *** affinity law that is established shows good applicability to the three-stage radial multiphase pump,with goodness of fit R^(2)larger than 0.9 for the two-phaseΨ_(m)–Φ_(m)andΠ_(m)–Φ_(m)performance ***,experimental results indicate that the affinity law also has good applicability to multiphase pumps with different stage numbers and blade structures under gas–liquid conditions.

关键词： flow law radial

Zif-L(Co) Derived Cobalt Doped In2o3 Hollow Nanofibers with High Surface Activity for Efficient Formaldehyde Gas Sensing

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SSRN 2023年

作者： Zhu, Lei Wang, Jianan Liu, Jianwei Wang, Ze Sun, Shiyi Li, Mingtao Yan, Wei Xi’an Key Laboratory of Solid Waste Resource Regeneration and Recycling State Key Laboratory of Multiphase Flow Engineering Xi’an Jiaotong University Xi’an710049 China School of Physics and Electrical Engineering Weinan Normal University Chaoyang Street Weinan714099 China School of Chemistry and Chemical Engineering Xi’an University of Science & Technology Xi’an710054 China

Gas sensors based on semiconductor metal oxides are identified as a highly promising candidate for toxic gas detection, yet they still suffer from high operating temperature due to low surface activity at low temperature. To address this issue, we present an elaborate design for the homogeneous functionalization of ZIF-L(Co) derived cobalt (Co) catalysts into hollow In2O3 frameworks, aiming to highly activate the redox capacity and catalytic efficacy of the In2O3 sensor to HCHO gas. Benefiting from the Co catalysts doping boosts the catalytic activity and generates abundant oxygen vacancies, the optimized 1 wt% Co-doped In2O3 HNFs sensor exhibits a high response of 40.4 toward 100 ppm HCHO at a moderately low temperature of 180 ℃, which is 4 times higher than that of pristine In2O3 HNFs. Moreover, 1 wt% Co-doped In2O3 HNFs sensor has virtues of high selectivity and excellent long-term stability for HCHO sensing. This study highlights the important influence of Co catalyst on the modulation of surface active sites of metal oxides-based sensors, inspiring the development of cost-effective sensors for indoor hazardous gas monitoring. © 2023, The Authors. All rights reserved.

关键词： Cost effectiveness