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Trend prediction technology of condition maintenance for large water injection units

Xiaoli XU, Sanpeng DENG

《机械工程前沿(英文)》 2010年 第5卷 第2期   页码 171-175 doi: 10.1007/s11465-009-0091-0

摘要: Trend prediction technology is the key technology to achieve condition-based maintenance of mechanical equipment. Large-sized water injection units are key equipment in oilfields. The traditional preventive maintenance is not economical and cannot completely avoid vicious accidents. To ensure the normal operation of units and save maintenance costs, trend prediction technology is studied to achieve condition-based maintenance for water injection units. The main methods of the technology are given, the trend prediction method based on neural network is put forward, and the expert system based on the knowledge is developed. The industrial site verification shows that the proposed trend prediction technology can reflect the operating condition trend change of the water injection units and provide technical means to achieve condition-based predictive maintenance.

关键词: water injection units     condition-based maintenance     trend prediction    

凝析气藏的经济开采模式

刘廷元

《中国工程科学》 2001年 第3卷 第3期   页码 85-91

摘要:

液态凝析油是凝析气藏的重要产品,它的开采应该是有效而经济的。介绍了国外近20 a来在凝析气藏开采技术领域的各种经济模式,包括回注φd=75%干气、自流回注、注N2、注水、水气交替注和注CO2等开采模式。研究结果表明,这些开采模式同传统的降压开采方法相比,能够有效地适应地面-地下的各种复杂情况。

关键词: 凝析气藏     开采模式     注气     注氮     注水     注二氧化碳     经济    

Determination of selected semi-volatile organic compounds in water using automated online solid-phaseextraction with large-volume injection/gas chromatography/mass spectrometry

Yongtao LI, Christina L. MCCARTY, Ed J. GEORGE

《环境科学与工程前沿(英文)》 2011年 第5卷 第3期   页码 417-425 doi: 10.1007/s11783-011-0310-x

摘要: A rapid, sensitive, and cost-effective analytical method was developed for the analysis of selected semi-volatile organic compounds in water. The method used an automated online solid-phase extraction technique coupled with programmed-temperature vaporization large-volume injection gas chromatography/mass spectrometry. The water samples were extracted by using a fully automated mobile rack system based on x-y-z robotic techniques using syringes and disposable 96-well extraction plates. The method was validated for the analysis of 30 semi-volatile analytes in drinking water, groundwater, and surface water. For a sample volume of 10 mL, the linear calibrations ranged from 0.01 or 0.05 to 2.5μg·L , and the method detection limits were less than 0.1μg·L . For the reagent water samples fortified at 1.0μg·L and 2.0?μg·L , the obtained mean absolute recoveries were 70%–130% with relative standard deviations of less than 20% for most analytes. For the drinking water, groundwater, and surface water samples fortified at 1.0μg·L , the obtained mean absolute recoveries were 50%–130% with relative standard deviations of less than 20% for most analytes. The new method demonstrated three advantages: 1) no manipulation except the fortification of surrogate standards prior to extraction; 2) significant cost reduction associated with sample collection, shipping, storage, and preparation; and 3) reduced exposure to hazardous solvents and other chemicals. As a result, this new automated method can be used as an effective approach for screening and/or compliance monitoring of selected semi-volatile organic compounds in water.

关键词: automated solid-phase extraction     programmed-temperature vaporization     large-volume injection     gas chromatography/mass spectrometry     semi-volatile organic compounds     water analysis    

Pragmatic multi-stage simulated annealing for optimal placement of synchrophasor measurement units in

Pathirikkat GOPAKUMAR,M. JAYA BHARATA REDDY,Dusmata Kumar MOHANTA

《能源前沿(英文)》 2015年 第9卷 第2期   页码 148-161 doi: 10.1007/s11708-015-0344-z

摘要: Conventional power grids across the globe are reforming to smart power grids with cutting edge technologies in real time monitoring and control methods. Advanced real time monitoring is facilitated by incorporating synchrophasor measurement units such as phasor measurement units (PMUs) to the power grid monitoring system. Several physical and economic constraints limit the deployment of PMUs in smart power grids. This paper proposes a pragmatic multi-stage simulated annealing (PMSSA) methodology for finding the optimal locations in the smart power grid for installing PMUs in conjunction with existing conventional measurement units (CMUs) to achieve a complete observability of the grid. The proposed PMSSA is much faster than the conventional simulated annealing (SA) approach as it utilizes controlled uphill and downhill movements during various stages of optimization. Moreover, the method of integrating practical phasor measurement unit (PMU) placement conditions like PMU channel limits and redundant placement can be easily handled. The efficacy of the proposed methodology has been validated through simulation studies in IEEE standard bus systems and practical regional Indian power grids.

关键词: phasor measurement units (PMUs)     pragmatic PMU placement     simulated annealing (SA)     western region Indian power grid (WRIPG)    

特低渗透油田提压注水效果探讨与实践

张洪亮

《中国工程科学》 2012年 第14卷 第4期   页码 62-64

摘要:

大庆西部外围地区特低渗透扶余油层具有埋藏深、厚度薄、砂体零散的特点,针对首次注水开发的特低渗透油田注水井吸水能力差、难以有效开发动用的实际,在搞清该区块微观特征的基础上,为确保特低渗透储层达到建立有效驱替,“注够水、注好水”的目的,经过反复理论研究和论证,提出了单井增压注水试验,现场应用后注水井能够完成配注,周围油井明显见到增油效果,实现了特低渗透储层有效驱替。利用无源微地震和同位素监测资料分析,改善了吸水状况,缓解了层间矛盾,储层动用程度得到提高。随注水压力升高降低,注水波及区范围随之升高、降低,增压注

关键词: 增压注水     无源微地震     特低渗透油田     波及系数     有效驱替    

Distribution and potential ecological risk of heavy metals in the typical eco-units of Haihe River Basin

Jingling LIU,Tao YANG,Qiuying CHEN,Feng LIU,Binbin WANG

《环境科学与工程前沿(英文)》 2016年 第10卷 第1期   页码 103-113 doi: 10.1007/s11783-014-0686-5

摘要: The distribution and characteristics of seven heavy metals in sediments located in the typical ecological units (eco-units) (e.g., rivers, lakes, and estuaries) of Haihe River Basin were analyzed. The Hakanson potential ecological risk index was used for ecological risk assessment. The results indicated that the concentration scales of As, Hg, Cr, Cd, Pb, Cu, and Zn in the eco-units were 2.08 to 24.80 mg·g , 0.01 to 1135.50 mg·g , 28.70 to 152.73 mg·g , 0.03 to 195765.83 mg·g , 8.65 to 157.82 mg·g , 6.47 to 178.61 mg·g , and 21.09 to 1076.25 mg·g , respectively. The maximum concentrations of Hg, Cd, and Zn showed higher levels than other water bodies around the world. Hg and Cd have high concentrations in Zhangweinanhe River (1135.50 and 195765.83 mg·g , respectively) and Haihe Estuary (790.50 and 548.47 mg·g , respectively). According to the ecological factor, Cd and Hg showed very strong ecological risks. The seven heavy metals, namely, Cd, Hg, As, Cr, Pb, Cu, and Zn, exhibited ecological risk levels in descending order. Based on the potential ecological risk index, Luanhe River and Baiyangdian Lake had moderate ecological risks, whereas every site in Zhangweinanhe River and Haihe Estuary had substantial risk levels. The risk order of the typical eco-units are as follows: Zhangweinan River (2278345.68)>Estuary (161914.74)>Luanhe River (191.54)>Baiyangdian Lake (120.95). These results provided a scientific basis for water environment improvement and risk management of the Haihe River Basin.

关键词: Haihe River Basin     ecological risk     eco-units     heavy metals    

Reliability prediction and its validation for nuclear power units in service

Jinyuan SHI,Yong WANG

《能源前沿(英文)》 2016年 第10卷 第4期   页码 479-488 doi: 10.1007/s11708-016-0425-7

摘要: In this paper a novel method for reliability prediction and validation of nuclear power units in service is proposed. The equivalent availability factor is used to measure the reliability, and the equivalent availability factor deducting planed outage hours from period hours and maintenance factor are used for the measurement of inherent reliability. By statistical analysis of historical reliability data, the statistical maintenance factor and the undetermined parameter in its numerical model can be determined. The numerical model based on the maintenance factor predicts the equivalent availability factor deducting planed outage hours from period hours, and the planed outage factor can be obtained by using the planned maintenance days. Using these factors, the equivalent availability factor of nuclear power units in the following 3 years can be obtained. Besides, the equivalent availability factor can be predicted by using the historical statistics of planed outage factor and the predicted equivalent availability factor deducting planed outage hours from period hours. The accuracy of the reliability prediction can be evaluated according to the comparison between the predicted and statistical equivalent availability factors. Furthermore, the reliability prediction method is validated using the nuclear power units in North American Electric Reliability Council (NERC) and China. It is found that the relative errors of the predicted equivalent availability factors for nuclear power units of NERC and China are in the range of –2.16% to 5.23% and –2.15% to 3.71%, respectively. The method proposed can effectively predict the reliability index in the following 3 years, thus providing effective reliability management and maintenance optimization methods for nuclear power units.

关键词: nuclear power units in service     reliability     reliability prediction     equivalent availability factors    

特高含水期分层段周期注采技术研究与实践认识

姜振海

《中国工程科学》 2012年 第14卷 第4期   页码 77-82

摘要:

针对萨北开发区油层沉积特点及特高含水期剩余油分布特点,以水动力学原理为指导,在已有周期注水实践经验的基础上,结合数值模拟进行机理研究,优化周期注采方式及各项参数,引入了分层段交叉注采改变液流方向改善开发效果的做法,在实践中取得了较好的效果。

关键词: 周期注水     周期采油     方式优化     参数优选    

Capacity limitation of nuclear units in grid based on analysis of frequency regulation

Yiping DAI, Pan JIANG, Lin GAO, Weimin KAN, Xiaoqing XIAO, Ge JIN

《能源前沿(英文)》 2012年 第6卷 第2期   页码 148-154 doi: 10.1007/s11708-012-0174-1

摘要: The increasing capacity of nuclear units in power grid poses threat to system stability and security. Load disturbance may cause overspeed of the units and trigger the overspeed protection controller (OPC). Repeating actions of valves have a strong impact on the security of the equipment and may result in a collapse of the power system. Based on the analysis of frequency regulation, mathematic models for nuclear units in the grid are established in this paper to simulate the dynamic process when load disturbance occurs. The critical action of the OPC is proposed as the constraint of safe operation for the units. The relationship between different styles of frequency regulation and the allowable capacity of the nuclear units in the grid is discussed. This research can help to estimate the capacity limitation of nuclear units in the grid.

关键词: nuclear units capacity     overspeed     primary frequency control (PFC)     second frequency control (SFC)    

Three-dimensional numerical simulation for plastic injection-compression molding

Yun ZHANG, Wenjie YU, Junjie LIANG, Jianlin LANG, Dequn LI

《机械工程前沿(英文)》 2018年 第13卷 第1期   页码 74-84 doi: 10.1007/s11465-018-0490-1

摘要:

Compared with conventional injection molding, injection-compression molding can mold optical parts with higher precision and lower flow residual stress. However, the melt flow process in a closed cavity becomes more complex because of the moving cavity boundary during compression and the nonlinear problems caused by non-Newtonian polymer melt. In this study, a 3D simulation method was developed for injection-compression molding. In this method, arbitrary Lagrangian-Eulerian was introduced to model the moving-boundary flow problem in the compression stage. The non-Newtonian characteristics and compressibility of the polymer melt were considered. The melt flow and pressure distribution in the cavity were investigated by using the proposed simulation method and compared with those of injection molding. Results reveal that the fountain flow effect becomes significant when the cavity thickness increases during compression. The back flow also plays an important role in the flow pattern and redistribution of cavity pressure. The discrepancy in pressures at different points along the flow path is complicated rather than monotonically decreased in injection molding.

关键词: injection-compression molding     simulation     injection molding     melt flow     cavity pressure    

density measurement for plastic injection molding via ultrasonic technology

《机械工程前沿(英文)》 2022年 第17卷 第4期 doi: 10.1007/s11465-022-0714-2

摘要: Density variation during the injection molding process directly reflects the state of plastic melt and contains valuable information for process monitoring and optimization. Therefore, in-situ density measurement is of great interest and has significant application value. The existing methods, such as pressure−volume−temperature (PVT) method, have the shortages of time-delay and high cost of sensors. This study is the first to propose an in-situ density measurement method using ultrasonic technology. The analyses of the time-domain and frequency-domain signals are combined in the proposed method. The ultrasonic velocity is obtained from the time-domain signals, and the acoustic impedance is computed through a full-spectral analysis of the frequency-domain signals. Experiments with different process conditions are conducted, including different melt temperature, injection speed, material, and mold structure. Results show that the proposed method has good agreement with the PVT method. The proposed method has the advantages of in-situ measurement, non-destructive, high accuracy, low cost, and is of great application value for the injection molding industry.

关键词: ultrasonic measurement     melt density     in-situ measurement     injection molding    

干热岩辅助采油可行性研究

王学忠

《中国工程科学》 2011年 第13卷 第3期   页码 104-106

摘要:

为降低稠油热采成本,以燃烧原油生产蒸汽进行热力开采的开发方式需要改变,同时需要减少注入水对油层造成的冷伤害,因此开展了干热岩辅助采油可行性研究。干热岩辅助采油技术是利用干热岩抽取地下热能加热油层,以降低原油粘度、提高原油流动能力。在技术配套方面,无论钻深井,还是稠油热采技术,都是成熟的。干热岩的热能源于核幔边界的地热,分布广泛、清洁、可再生。研究表明,干热岩辅助采油技术针对性较强,是对现有蒸汽吞吐+蒸汽驱热采技术的有效继承,技术上具有可行性,并有可能推动相关技术的发展,符合中国节能减排的基本国策。建议在有利区块率先开展先导试验。

关键词: 干热岩辅助采油     冷伤害     热采稠油     热水驱     水热裂解    

Intelligent methods for the process parameter determination of plastic injection molding

Huang GAO, Yun ZHANG, Xundao ZHOU, Dequn LI

《机械工程前沿(英文)》 2018年 第13卷 第1期   页码 85-95 doi: 10.1007/s11465-018-0491-0

摘要:

Injection molding is one of the most widely used material processing methods in producing plastic products with complex geometries and high precision. The determination of process parameters is important in obtaining qualified products and maintaining product quality. This article reviews the recent studies and developments of the intelligent methods applied in the process parameter determination of injection molding. These intelligent methods are classified into three categories: Case-based reasoning methods, expert system-based methods, and data fitting and optimization methods. A framework of process parameter determination is proposed after comprehensive discussions. Finally, the conclusions and future research topics are discussed.

关键词: injection molding     intelligent methods     process parameters     optimization    

利用注水前缘监测技术跟踪水推速度

杨志冬,周金燕,常智勇,张金荣,韩铭毅

《中国工程科学》 2012年 第14卷 第4期   页码 31-33

摘要:

讨论了红032井区注水前缘分布及微地震监测结果。结果表明,微地震注水前缘监测结果与油田地质数值模拟结果、地震波幅分布结果一致。由微地震监测结果可以确定注入水推进位置,为油田注水方案调整、改进注采措施、提高注水效率提供依据。

关键词: 注水前缘监测     优势流动方向     注水调控    

Optimal operation of energy at hydrothermal power plants by simultaneous minimization of pollution and costs using improved ABC algorithm

Homayoun EBRAHIMIAN,Bahman TAHERI,Nasser YOUSEFI

《能源前沿(英文)》 2015年 第9卷 第4期   页码 426-432 doi: 10.1007/s11708-015-0376-4

摘要: The aim of this paper is simultaneous minimization of hydrothermal units to reach the best solution by employing an improved artificial bee colony (ABC) algorithm in a multi-objective function consisting of economic dispatch (ED) considering the valve-point effect and pollution function in power systems in view of the hot water of the hydro system. In this type of optimization problem, all practical constraints of units were taken into account as much as possible in order to comply with the reality. These constraints include the maximum and minimum output power of units, the constraints caused by the balance between supply and demand, the impact of pollution, water balance, uneven production curve considering the valve-point effect and system losses. The proposed algorithm is applied on the studied system, and the obtained results indifferent operating conditions are analyzed. To investigate in various operating conditions, different load profiles in 12 h are taken into account. The obtained results are compared with those of the other methods including the genetic algorithm (GA), the Basu technique, and the improved genetic algorithm. Fast convergence is one of this improved algorithm features.

关键词: practical constraints of units     pollution function     inlet steam valve     up-ramp rate of units     improved ABC algorithm    

标题 作者 时间 类型 操作

Trend prediction technology of condition maintenance for large water injection units

Xiaoli XU, Sanpeng DENG

期刊论文

凝析气藏的经济开采模式

刘廷元

期刊论文

Determination of selected semi-volatile organic compounds in water using automated online solid-phaseextraction with large-volume injection/gas chromatography/mass spectrometry

Yongtao LI, Christina L. MCCARTY, Ed J. GEORGE

期刊论文

Pragmatic multi-stage simulated annealing for optimal placement of synchrophasor measurement units in

Pathirikkat GOPAKUMAR,M. JAYA BHARATA REDDY,Dusmata Kumar MOHANTA

期刊论文

特低渗透油田提压注水效果探讨与实践

张洪亮

期刊论文

Distribution and potential ecological risk of heavy metals in the typical eco-units of Haihe River Basin

Jingling LIU,Tao YANG,Qiuying CHEN,Feng LIU,Binbin WANG

期刊论文

Reliability prediction and its validation for nuclear power units in service

Jinyuan SHI,Yong WANG

期刊论文

特高含水期分层段周期注采技术研究与实践认识

姜振海

期刊论文

Capacity limitation of nuclear units in grid based on analysis of frequency regulation

Yiping DAI, Pan JIANG, Lin GAO, Weimin KAN, Xiaoqing XIAO, Ge JIN

期刊论文

Three-dimensional numerical simulation for plastic injection-compression molding

Yun ZHANG, Wenjie YU, Junjie LIANG, Jianlin LANG, Dequn LI

期刊论文

density measurement for plastic injection molding via ultrasonic technology

期刊论文

干热岩辅助采油可行性研究

王学忠

期刊论文

Intelligent methods for the process parameter determination of plastic injection molding

Huang GAO, Yun ZHANG, Xundao ZHOU, Dequn LI

期刊论文

利用注水前缘监测技术跟踪水推速度

杨志冬,周金燕,常智勇,张金荣,韩铭毅

期刊论文

Optimal operation of energy at hydrothermal power plants by simultaneous minimization of pollution and costs using improved ABC algorithm

Homayoun EBRAHIMIAN,Bahman TAHERI,Nasser YOUSEFI

期刊论文