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11.
Xingchao WANG Chunjian PAN Carlos E. ROMERO Zongliang QIAO Arindam BANERJEE Carlos RUBIO-MAYA Lehua PAN 《Frontiers in Energy》2022,16(2):246
A comprehensive thermo-economic model combining a geothermal heat mining system and a direct supercritical CO2 turbine expansion electric power generation system was proposed in this paper. Assisted by this integrated model, thermo-economic and optimization analyses for the key design parameters of the whole system including the geothermal well pattern and operational conditions were performed to obtain a minimal levelized cost of electricity (LCOE). Specifically, in geothermal heat extraction simulation, an integrated wellbore-reservoir system model (T2Well/ECO2N) was used to generate a database for creating a fast, predictive, and compatible geothermal heat mining model by employing a response surface methodology. A parametric study was conducted to demonstrate the impact of turbine discharge pressure, injection and production well distance, CO2 injection flowrate, CO2 injection temperature, and monitored production well bottom pressure on LCOE, system thermal efficiency, and capital cost. It was found that for a 100 MWe power plant, a minimal LCOE of $0.177/kWh was achieved for a 20-year steady operation without considering CO2 sequestration credit. In addition, when CO2 sequestration credit is $1.00/t, an LCOE breakeven point compared to a conventional geothermal power plant is achieved and a breakpoint for generating electric power generation at no cost was achieved for a sequestration credit of $2.05/t. 相似文献
12.
为研究用于工业真空制备二元冰的最佳工况,本文基于静态闪蒸理论,设计并搭建了一套固体吸附条件下乙醇溶液真空闪蒸制冰实验系统。在同一初始压力下(100 Pa),研究了不同乙醇浓度、环境温度和多壁碳纳米管尺寸对静态闪蒸制冰特性的影响。结果表明:乙醇的添加在防止重结晶的同时可以降低蒸馏水真空闪蒸制冰的过冷度,较高浓度的乙醇溶液不利于闪蒸制冰,5%质量浓度的乙醇溶液闪蒸特性稳定,可将蒸馏水过冷度降低60. 62%,较适合静态闪蒸制冰;随着环境温度升高,闪蒸室内溶液闪蒸量增大,随着环境温度从10℃升至20℃,闪蒸率从25. 45%增至44. 04%。较低的环境温度有利于真空闪蒸制冰;随着添加多壁碳纳米管粒径的减小,乙醇溶液过冷度减小,当多壁碳纳米管外径为5~18 nm时,真空闪蒸的含冰率相对于5%质量浓度的乙醇溶液提高51. 45%,相对于蒸馏水提高38. 22%。过冷度相对于5%质量浓度的乙醇溶液降低24. 36%,相对于蒸馏水降低70. 21%,对于减小蒸馏水过冷度和提高含冰率效果显著。 相似文献
13.
针对特高压直流系统逆变侧阀侧接地故障可能引发换流变压器故障性涌流的问题,讨论故障位于不同电压等级换流桥以及不同时刻下阀桥通断情况的差异,分析换相失败后阀侧故障电流特征,阐述逆变侧故障性涌流产生机理及其特征。在此基础上,分析计及故障性涌流影响的换流变差动保护动作特性。研究结果表明,故障性涌流可能导致换流变区外转区内故障时差动保护误闭锁,针对该问题,根据故障时阀侧电流直流分量发生极性反转的特点,提出一种新的防止差动保护误闭锁的解决方案。PSCAD/EMTDC仿真结果验证了理论分析的正确性。 相似文献
14.
Lei Zhang Jing Li Songtao Yang Bin Wang Xingchao Bian 《Wireless Personal Communications》2018,101(2):943-961
In location-based service (LBS), the un-trusted LBS server can preserve lots of information about the user. Then the information can be used as background knowledge and initiated the inference attack to get user’s privacy. Among the background knowledge, the profile attribute of users is the especial one. The attribute can be used to correlate the real location in uncertain location set in both of the snapshot and continuous query, and then the location privacy of users will be revealed. In most of the existing scheme, the author usually assumes a trusted third party (TTP) to achieve the profile anonymity. However, as the TTP disposes all anonymous procedure for each user, it will become the center of attacks and the bottleneck of the query service. Furthermore, the TTP may be curious about user’s privacy just because of the commercial consideration. In order to deal with the inference attack and remedy the drawback of TTP scheme, we propose a similar attributes anonymous scheme which based on the CP-ABE, and with the help of center server and collaborative users, our scheme can resist the inference attack as well as the privacy detection of any entity in the service of query. At last, security analysis and experimental results further verify the effectiveness of our scheme in privacy protection as well as efficiency of the algorithm execution. 相似文献
15.
Preparation of carbon/carbon‐ultra high temperature ceramics composites with ultra high temperature ceramics coating
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Lin Xu Jia Cheng Xingchao Li Yin Zhang Zhen Fan Yongzhong Song Zhihai Feng 《Journal of the American Ceramic Society》2018,101(9):3830-3836
In order to increase the oxidation resistance of carbon/carbon (C/C) composites at long‐term high temperature, C/C‐Ultra High Temperature Ceramics composites (UHTCs) with a dual‐layer UHTCs oxidation coating was successfully designed and fabricated. The microstructure and ablation resistance were investigated and discussed. After ablation in arc‐heated wind tunnel with temperature being 2200°C for 1000s, the mass ablation rate and linear ablation rate were ?1.9 × 10?2 mg/cm2s and 2.9 × 10?5 mm/s, respectively. The formation of thermodynamically compatible oxide scale including ZrO2 skeleton and SiO2 or Zr–Si–O glass on the surface were mainly contributed to the excellent ablation resistance of the composite. 相似文献
16.
蠕变地层套管载荷分析研究 总被引:26,自引:2,他引:26
研究了蠕变地层中套管载荷的分布规律。首先,件下蠕变地层中套管的载荷。其次,采用有限元方法,将套管看成弹性支撑,采用解析方法确定了均匀地应力条研究了非均匀地应力条件下蠕变地层中套管的载荷。不论是均匀地应力还是非均匀地应力条件,经过足够长的时间,套管载荷都将接近于完全弹性解。同时,通过数值计算,得出了非均匀地应力条件下与现有套管载荷分布规律相反的结论。 相似文献
17.
增量式光学编码器在制造与安装的过程中不可避免的会出现刻线误差和细分误差,这些误差会降低角度测量的精度并导致瞬时角速度(IAS)信号波动,研究刻线与细分误差的补偿途径有重要意义,但现有方法存在误差补偿效率低,不易现场应用等局限。针对上述问题,本文首先对增量式光学编码器的刻线误差与细分误差进行分析并建立误差模型,揭示了刻线误差、细分误差与IAS信号波动之间的联系。在此基础上提出了一种使用IAS信号对增量式光学编码器刻线与细分误差进行补偿的方法,该方法具有效率高、无需对编码器进行改装等优点。通过仿真分析对本文所建立的误差模型的正确性与误差估计方法的可行性进行了验证,并在RV传动实验台上对伺服电机末端的增量式光学编码器进行刻线与细分误差补偿,最后使用光学旋转平台对增量式光学编码器误差进行测量,通过对比分析验证了本文所提方法的有效性。 相似文献
18.
19.
为优化稻谷流化床干燥工艺,采用三因素三水平Box-Behnken响应面分析法,研究干燥温度、降水幅度、缓苏时间对稻谷流化床干燥降水速率和干燥稻谷爆腰增率、垩白粒率、脂肪酸值、硬度、黏着性等品质指标的影响。结果表明:随着干燥温度和降水幅度水平的增加,稻谷降水速率、爆腰增率、垩白粒率和米饭硬度增加,脂肪酸值和米饭黏着性降低;随着缓苏时间延长,稻谷降水速率、爆腰增率、脂肪酸值和米饭硬度降低,米饭黏着性增加。而在较低的干燥温度条件下,缓苏时间延长,稻谷的爆腰增率和垩白粒率降低并不明显。Box-Behnken响应面分析法优化的流化床最优干燥参数为降水幅度2.50%(干基)、干燥温度45 ℃、缓苏时间3 h,此时隶属度综合分达最大值0.75。验证实验结果与拟合值无显著性差异(P<0.05),优化结果可靠有效。 相似文献
20.
TiO2-doped carbon aerogels (CAs) were synthesized by sol–gel polymerization of a mixture of resorcinol, formaldehyde and tetrabutyl
orthotitanate, followed by gelation and supercritical drying and carbonization in N2 gas atmosphere. The morphology of these TiO2-doped CAs was characterized by transmission electron microscopy. X-ray diffraction and Brunauer–Emmett–Teller methods were
employed to determine the microstructure and surface characteristics of samples. It was found that the doped TiO2 had no significant effect on the surface area of the samples, whereas the pore and mesopore volumes were increased by the
addition of TiO2. The TiO2 particles were kept still as anatase in samples carbonized at 900 °C, and did not transform into rutile on heating. Electrochemical
performance of the samples as electrode materials was studied by cyclic voltammetry, electrochemical impedance spectroscopy,
and constant current charge/discharge measurements. The results showed that the specific capacitance of CA electrodes had
been improved by TiO2 doping, and the samples with wider pore diameters have higher capacitance values. 相似文献