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Thermodynamic Analysis and Case Study of a New Lignite-Fired power Plant Using Solar Energy as Drying Heat Source

JOURNAL OF ENERGY engineering 2020年第3期146卷

作者： Wang, Chang'an Zhu, Xin Yuan, Maobo Che, Defu Xi An Jiao Tong Univ Sch Energy & Power Engn State Key Lab Multiphase Flow Power Engn Xian 710049 Shaanxi Peoples R China

Lignite usually has a high moisture content and low calorific value, and should be predried before combustion to enhance power generation efficiency. Steam extracted from steam turbine and boiler exhaust gas are often applied in lignite predrying systems. However, the bleeding gas from the steam turbine reduces its output, and the exhaust gas originating from the boiler has insufficient drying capacity. In the present work, a new lignite power plant integrated with a solar drying system is proposed. A solar energy collection and storage tank system were employed to solve the problem of low heat density and instability of solar energy. Thermodynamic analysis results show that the area of reflectors declines at a decreasing rate with an increase in the direct normal irradiation (DNI). The power generation efficiencies of a solar drying lignite power plant (SDPP) and steam extraction drying power plant (SEDPP) can be increased by 0.68% and 0.33% for every 0.1 kg/kg rise in the drying degree. When the drying degree is 0.3 and DNI is 0.5 kW/m2, the economic analysis indicates that the simple payback periods for a conventional lignite power plant, SDPP, and SEDPP are 2.38, 3.20, and 2.53 years, respectively. In addition, the solar-to-electricity efficiency declines at a decreasing rate with increasing drying degree. The power generation efficiency of SDPP with dryer exhaust recovery is increased by 0.83% for each 0.1 kg/kg increase in the drying degree.

关键词： Lignite power plant Solar drying Thermodynamic analysis Energy recovery

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Cavitation characteristics of rotary vane pump in aeroengine lubricating oil system and their effects on pump performance

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Hangkong Dongli Xuebao/Journal of Aerospace power 2025年第7期40卷

作者： Wang, Ge Wang, Yijin He, Denghui Yang, Lina Cao, Ming Bai, Bofeng State Key Laboratory of Eco-hydraulic in Northwest Arid Region of China Xi’an University of Technology Xi’an710048 China Department of Power Engineering Institute of Water Resources and Hydro-electric Engineering Xi’an University of Technology Xi’an710048 China State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an710049 China Commercial Aircraft Engine Company Limited Aero Engine Corporation of China Shanghai200241 China Shanghai Center of Research for Commercial Aircraft Engine Engineering Techniques Shanghai200241 China

To meet the demand for high-performance oil pumps in the lubricating oil system of high thrust and high-speed aeroengines, numerical simulation was conducted on a new high-speed rotary vane oil pump. The Mixture multiphase flow model, Singhal full cavitation model, and renormalization group（RNG） k-Ε turbulence model were employed for numerical calculation, and the reliability of the numerical simulation method was verified through experiments. Then, cavitation characteristics of the rotary vane pump and its impact on pump performance under different inlet pressure and oil temperature conditions were analyzed. The results showed that the cavitation gas was mainly distributed in the volume chamber on the oil suction side, as well as on the suction surface of the rotary vane and near the inner wall of the rotor. With the decrease of inlet pressure and the increase of oil temperature, the cavitation phenomenon inside the rotary vane pump intensified, and the cavitation gas increased, which in turn led to a decrease in the average oil discharge flow rate at the pump outlet and a decrease in volumetric efficiency. When the inlet pressure dropped to 40 kPa and the temperature rose to 373.15 K, the average oil discharge flow rate and volumetric efficiency at the pump outlet both significantly decreased. The pressure pulsation at the monitoring point exhibited low-frequency and high-amplitude pulsation characteristics. The cavitation of the rotary vane pump affected not only its oil discharge and volumetric efficiency, but also the stable and reliable operation of the pump. © 2025 Beijing University of Aeronautics and Astronautics (BUAA). All rights reserved.

关键词： Vane pumps

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Oriented thermal etching of hollow carbon spheres with delicate heat management for efficient solar steam generation

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INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER 2021年 178卷 121579-121579页

作者： Tan, Yubo Liu, Maochang Wei, Daixing Ren, Jun Wang, Yechun Jin, Hui Shen, Shaohua Xi An Jiao Tong Univ State Key Lab Multiphase Flow Power Engn Int Res Ctr Renewable Energy Xian Peoples R China North Univ China Sch Chem Engn & Technol Taiyuan 030051 Shanxi Peoples R China

Hollow carbon spheres (HCSs) with controllable morphology and structure have received considerable attention in the field of energy conversion and storage. Herein, monodispersed HCSs with cavity sizes tuned from 100 nm to 800 nm and shell thickness from 450 nm to 50 nm were successfully synthe-sized through a unique template-free thermal-etching method. It was evidenced that the dynamically controllable synthesis of HCSs was attributed to the "inside-out" oriented thermal oxidation etching of carbon spheres (CSs) induced by the differentiated "core-shell" chemical structures. Comparing to CSs, the obtained HCSs exhibited much increased efficiency for solar-driven interfacial steam generation (SISG), reaching as high as 88.9%, which outperforms most of the previously reported carbon-based materi-als. It was then demonstrated that the rational heat management for both photothermal and thermal-evaporation conversion is essential to achieve satisfying SISG efficiency. Depending on the increasing cav-ity sizes, HCSs presented gradual increases in both photothermal conversion and thermal-evaporation performances, mainly attributed to the improved light absorption and the delicate heat management, respectively. However, the further increase in cavity size resulted in excessive heat loss and presented decreased thermal-evaporation performance. This work provides an alternative and promising approach to the reasonable design of hollow nanostructures with delicate heat management for efficient SISG as well as other solar energy conversion applications. (c) 2021 Elsevier Ltd. All rights reserved.

关键词： Hollow carbon spheres Solar steam generation Heat management Photothermal conversion Thermal-evaporation conversion

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Measurements of isochoric specific heat capacity for 3,3,3-trifluoroprop-1-ene (R1243zf) at temperatures from (250 to 300) K and pressures up to 10 MPa

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JOURNAL OF CHEMICAL THERMODYNAMICS 2021年 161卷 106494-106494页

作者： Ding, Li Sheng, Bowen Hou, Yu Dong, Xueqiang Zhao, Yanxing Xu, Hongbo Shen, Jun Gong, Maoqiong Xi An Jiao Tong Univ State Key Lab Multiphase Flow Power Engn Xian 710049 Peoples R China Chinese Acad Sci Tech Inst Phys & Chem Key Lab Cryogen Beijing 100190 Peoples R China Univ Chinese Acad Sci Beijing 100049 Peoples R China

In this paper, a total of 86 isochoric specific heat capacity (c(v)) data of 3,3,3-trifluoroprop-1-ene (R1243zf) at temperatures from (250 to 300) K and pressures up to 10 MPa were measured using an adiabatic batch calorimeter. The standard uncertainties of temperature, pressure and isochoric specific heat capacity were estimated to be 12 mK, 5 kPa and 0.95%, respectively. A comparison was conducted between the experimental c(v) data and values calculated by three equations including the Helmholtz energy EOS (Akasaka and Lemmon, 2019) in REFPROP 10.0, the generalized equation (Zhong et al., 2019) and the corresponding states equation (Sheng et al., 2020) with the average absolute relative deviations (AARDs) of 2.43%, 0.91% and 0.84%, respectively. Among three equations, the corresponding states equation developed by Sheng et al. gives the best predictive performance for the liquid heat capacity of R1243zf. (C) 2021 Elsevier Ltd.

关键词： Adiabatic calorimeter R1243zf Isochoric specific heat capacity Compressed liquid

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Chlorine-promoted perovskite nanocomposite as a high-performance oxygen transfer agent for chemical looping methane-assisted CO2 splitting

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CHEMICAL engineering JOURNAL ADVANCES 2020年 4卷

作者： Chen, Cunzhuang Yu, Wenbo Duan, Yifei Wang, Xinhe Zhang, Junshe Xian Jiaotong Univ Xian Sch Chem Engn & Technol Xian 710049 Shaanxi Peoples R China Xi An Jiao Tong Univ State Key Lab Multiphase Flow Power Engn Xian 710049 Shaanxi Peoples R China

Metal oxide-mediated CO2 splitting with the assistance of methane (aka chemical looping dry reforming of methane) is a novel and attractive approach for CO2 utilization. Herein, we demonstrate that doping and tai-loring the redox window of strontium ferrite (SrFeO3-8)-calcium oxide nanocomposites are effective strategies to improve the performance of chemical looping reforming. The oxygen storage capacity of this redox material is about 0.82 mol O/kg. Chlorine promotes coking in the reduction step;the tailored window not only suppresses complete oxidation of methane but also enhances CO2 transformation in a fixed-bed reactor. At 980 degrees C, the carbon efficiency is as high as 99%, very close to the equilibrium value. In this case, no recycling or downstream separa-tion is needed, making the proposed scheme more efficient. In addition, both the yield of CO and the productivity of syngas remain stable over 10 redox cycles. This exceptional redox performance makes the chloride-promoted SrFeO3-8-based nanocomposites a highly competitive and cost-effective chemical looping material.

关键词： Perovskite nanocomposite CO 2 splitting Methane Chemical looping

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Ultrastructure of Critical-Gel-like Polyzwitterion-Polyoxometalate Complex Coacervates: Effects of Temperature, Salt Concentration, and Shear

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MACROMOLECULES 2020年第24期53卷 10972-10980页

作者： Jing, Benxin Ferreira, Manuela Lin, Kehua Li, Ruipeng Yavitt, Benjamin M. Qiu, Jie Fukuto, Masafumi Zhu, Yingxi Wayne State Univ Dept Chem Engn & Mat Sci Detroit MI 48202 USA Brookhaven Natl Lab Natl Synchrotron Light Source 2 Upton NY 11973 USA Xi An Jiao Tong Univ Sch Nucl Sci & Technol Xian 710049 Peoples R China Xi An Jiao Tong Univ State Key Lab Multiphase Flow Power Engn Xian 710049 Peoples R China

The structure of unconventional complex coacervates, such as polymer-nonpolymer complex coacervates, remains less investigated than that of the conventional coacervates formed between oppositely charged polyelectrolytes with symmetric charge species. Yet, their microscopic structural organization is important to further elucidate the mechanism of liquid-liquid-phase separation processes upon complexation. In this work, we characterize the microstructural organization of complex coacervates formed between inorganic polyoxometalate (POM) and polyzwitterion by small-angle X-ray scattering (SAXS) with in situ temperature and shear control. Despite the apparent transparent and homogeneous morphology of dense coacervates as observed by optical microscopy, our previous results (Macromolecules 2018, 51, 22, 9405-9411) suggest that dense polyzwitterion-POM coacervates exhibit critical-gel-like networks containing both complex-poor region (mesh pore) and complex-rich region (connective network). SAXS results as reported in this work support that the complex-rich region is actually in the form of loosely packed POM aggregates linked by polyzwitterion, designated as complex particles. The structure of aggregating complex particles is further examined against varied composition and salt concentrations, temperature, and shear, thanks to the high X-ray scattering contrast of POMs from that of other components in the coacervates. The complex particles in the dense coacervates appear to grow with more tightly packed POM aggregates with increasing POM-to-polyzwitterion concentration ratio, in contrast to more loosely packed POM aggregates with decreasing salt concentration. Conversely, increasing temperature could result in smaller complex particles containing more loosely packed POM aggregates, consistent with temperature-dependent viscoelasticity of dense coacervates. Furthermore, such POM-based hybrid dense coacervates exhibit intriguing strain-hardening behavior, resulting from s

关键词： Scattering Chemical structure Anions Solution chemistry X-ray scattering

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Thermodynamic analysis and optimization of a dual-pressure Allam cycle integrated with the regasification of liquefied natural gas

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ENERGY CONVERSION AND MANAGEMENT 2021年 246卷 114660-114660页

作者： Li, Bo Wang, Shun-sen Qiao, Jiafei Wang, Bingbing Song, Liming Xi An Jiao Tong Univ Inst Turbomachinery Sch Energy & Power Engn State Key Lab Multiphase Flow Power Engn 28 Xianning West Rd Xian 710049 Peoples R China GUONENG GUOHUA BEIJING Elect Res Inst CO LTD Beijing Peoples R China

A novel dual-pressure Allam cycle integrated with the cold energy recovery of liquefied natural gas is proposed and analyzed in this paper. The feature of this system is that the cold energy of liquefied natural gas is successively utilized in two condensers with different condensing pressures, thereby reducing the heat transfer temperature difference in the condensation process and improving the system performance. The proposed system is discussed in detail based on the results of thermodynamic analysis and optimization. According to the simulation results, the largest exergy destruction belongs to the combustion chamber. Moreover, the exergy destruction in the condenser is greatly reduced owing to the dual-pressure condensation process. The system exergy efficiency first increases and then decreases with the increment of combustor temperature and main turbine inlet pressure. However, the system performance would deteriorate as the main turbine outlet pressure and bottom turbine outlet pressure increase. According to the results of single-objective optimization, the electricity efficiency and specific work of the dual-pressure Allam cycle are 15.76% and 68.75% higher than the classical Allam cycle, respectively. In addition, the exergy efficiency of the dual-pressure Allam cycle is up to 51.88%, which is improved by 1.57% compared with the single-pressure Allam cycle.

关键词： Dual pressure Allam cycle Liquefied natural gas Thermodynamic analysis Optimization

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Enhanced Ni/W/Ti Catalyst Stability from Ti-O-W Linkage for Effective Conversion of Cellulose into Ethylene Glycol

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ACS SUSTAINABLE CHEMISTRY & engineering 2020年第26期8卷 9650-9659页

作者： Li, Naixu Liu, Xu Zhou, Jiancheng Ma, Quanhong Liu, Maochang Chen, Wenshuai Southeast Univ Sch Chem & Chem Engn Nanjing 211189 Peoples R China Jiangsu Key Lab Biomass Energy & Mat Nanjing 210042 Peoples R China Xi An Jiao Tong Univ State Key Lab Multiphase Flow Power Engn Int Res Ctr Renewable Energy Xian 710049 Shaanxi Peoples R China Northeast Forestry Univ Key Lab Biobased Mat Sci & Technol Minist Educ Harbin 150040 Peoples R China

Direct conversion of cellulose into ethylene glycol is a promising route for transforming sustainable biomass resources into high-value chemicals. Although numerous attempts have been made to exploit tungsten-based hydrogenolysis catalysts in the catalytic conversion of cellulose to ethylene glycol for high conversion rate and selectivity, maintaining catalyst stability remains challenging. Herein, we have developed a Ni-W/M catalyst with good catalytic performance and stability, which were obtained by calcining Ni-W/MIL-125(Ti) precursor. The synthesized catalyst showed good cellulose conversion rate (100%) and ethylene glycol yield (68.7%). The tungsten species was linked to the TiO2 support by Ti-O-W bonds to reduce loss of the active tungsten component. The formation of new bonds enhanced the catalyst stability and durability, enabling the catalysts to retain high catalytic activity during recycling.

关键词： cellulose ethylene glycol MIL-125(Ti) stability catalysis

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Bismuth-based photocatalyst for photocatalytic oxidation of flue gas mercury removal: A review

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JOURNAL OF HAZARDOUS MATERIALS 2021年 418卷 126280-126280页

作者： Guan, Yu Liu, Yinhe Lv, Qiang Wu, Jiang Xi An Jiao Tong Univ State Key Lab Multiphase Flow Power Engn Sch Energy & Power Engn Xian 710049 Peoples R China Shanghai Univ Elect Power Coll Energy & Mech Engn Shanghai 200090 Peoples R China Shanghai Inst Pollut Control & Ecol Secur Shanghai Peoples R China

Photocatalytic oxidation method is a promising technology for solving flue gas mercury (Hg) pollution from industrial plants. Semiconductor photocatalysts have been widely applied in energy conversion and environmental remediation. However, key issues such as low light absorption capacity, wide energy band gap, and poor physicochemical stability severely limit the application of photocatalysts in practical industrial plants. In recent years, bismuth-based (Bi-based) photocatalysts, including bismuth oxide halide BiOX (X = Cl, Br or I), bismuth salt oxymetal BiVO4, and BiOIO3 etc., have increasingly aroused scientists' attention due to their peculiar crystalline geometric structures, tunable electronic structure and high photocatalytic performance. In present review, we firstly review the photocatalytic reaction mechanism and main photocatalytic oxidation mechanism of mercury. Secondly, the synthetic methods of Bi-based photocatalysts are summarized. Then, according to the mechanism of mercury removal, the experimental modifying approaches including heterojunction making, external atoms doping, defect creating, and crystal face regulating to promote the photocatalytic oxidation of mercury removal are summarized, as well as the determination of the band gap and electronic density of states (DOS) of Bi-based photocatalysts to elucidate the photocatalytic oxidation mechanism via density functional theory (DFT) calculation. Furthermore, constructing electronic transmission channels is an efficient way to improve the photocatalytic activity. Finally, challenges and perspectives of Bi-based photocatalyst for photocatalytic oxidation of mercury removal are presented. In addition, the excellent performance photocatalysts and efficient pollution removal equipment for mercury removal in industrial plants are still required in-depth study.

关键词： Bismuth-based photocatalyst Flue gas Heavy metal mercury Photocatalytic Oxidation

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Lattice-mismatch-induced growth of ultrathin Pt shells with high-index facets for boosting oxygen reduction catalysis

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JOURNAL OF MATERIALS CHEMISTRY A 2020年第32期8卷 16477-16486页

作者： Li, Xiang Liu, Yaming Bi, Wei Bi, Jinglei Guo, Ruiyun Li, Rui Wang, Chaoqi Zhan, Qi Wang, Weicong Yang, Shengchun Shi, Fenglei Wu, Jianbo Jin, Mingshang Xian Technol Univ Sch Mat & Chem Engn Xian 710021 Shaanxi Peoples R China Xi An Jiao Tong Univ Frontier Inst Sci & Technol State Key Lab Multiphase Flow Power Engn Xian 710049 Shaanxi Peoples R China Xi An Jiao Tong Univ Sch Sci State Key Lab Mech Behav Mat Key Lab Shanxi Adv Mat & Mesoscop Phys Xian 710049 Shaanxi Peoples R China Shanghai Jiao Tong Univ Sch Mat Sci & Engn State Key Lab Met Matrix Composites Shanghai 200240 Peoples R China

Owing to its high catalyzing nature, Pt holds great promise as an efficient catalyst for the oxygen reduction reaction (ORR). Although surface steps/kinks have been proven beneficial for the catalytic performance, constructing steps/kinks on Pt surfaces remains a big challenge due to the high surface energy. Herein, we demonstrate that the lattice mismatch can induce the growth of Pt shells with high-density steps on substrates. We exemplify it by depositing Pt shells on Pd-Cu alloy nanocubes, between which the lattice mismatch reaches 4.53%, and testing the resulting catalysts for the ORR. We show that Pt shells on Pd-Cu alloy nanocubes exhibit an extraordinary increase in both specific and mass activities of 32 and 16 times, respectively, as compared to the commercial Pt/C catalyst. Meanwhile, functional tests in proton exchange membrane fuel cells exhibit a 121.9 mW cm(-2)increase in power density for Pd-Cu@Pt compared to the commercial Pt/C catalyst. Our result indicates that lattice mismatch between Pt shells and Pd-Cu alloy cores plays a key role in forming surface steps, while Pt shells grown on Pd cores only cause the formation of Pd@Pt nanocubes without surface steps. This work suggests that lattice mismatch can serve as an efficient parameter for preparing ORR catalysts with excellent activity and durability.

关键词： Lattice mismatch

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