曹津长输原油管道清管作业实践

清管作业是长输管道投产或运行的一项重要工作。文中分析了曹津长输原油管道清管作业实践,结合清管设备、清管前的准备工作、清管工艺流程和清管器的跟踪方法对长输原油管道清管作业进行了详细的介绍,为长输管道投运、开展在线检测提供参考。     

鄯兰原油管道清管效果

含蜡原油管道运行一段时间后,会有石蜡沉积到管壁上,需进行清管作业。为了研究鄯兰原油管道清管的效果,文中结合生产数据和长输油管道输油技术理论,对2012年8月—2014年8月的清管数据进行对比,分析清管的效果,为清管作业提供数据参考。     

西部原油管道清管作业分析与研究

文中介绍了清管前管道内壁结蜡预测和清管器准备、作业实施的方法以及探索的清管器发送和类型变换的规律。总结了原油管道清管作业的前期准备工作、渐进式清管方式、清管器类型选择等相关经验,提出了后续原油管道清管周期优化的建议。     

含蜡热油管道清管过程的卡堵风险分析

现场清管作业时,清管器经常被卡堵,严重时会影响生产.因此,为降低热油管道清管过程中的卡堵风险,根据清管器在含蜡热油管道中的受力情况和运行规律,结合输油管道的现场运行管理经验,分析含蜡热油管道清管过程可能遇到的卡堵,对此提出可靠的应对措施,以杜绝含蜡热油管道周期性清管中各种事故的发生,保证热油管道清管工作的安全进行,为今...     

石空-兰州原油管道清管运行分析

石兰线管道所输油品为长庆油田高含蜡原油,管道沿线较长管段温度低,在运行中管壁结蜡现象明显,四墩至兰州、红湾至景泰管段油温最低,且管线运行状况未知,因此进行清管作业。压力分析及总传热系数分析表明,清管效果明显。应制定安全、合理的清管计划,满足管道平稳运行要求。     

北内环清管过程中清管球滞留问题研究

为保证北内环平稳、高效、安全输送天然气,对其进行清管通球。在清管过程中出现3次清管球滞留情况,针对这些滞留情况,从清管球在管道中的受力情况、清管球在三通处出现形状变化2个方面分析讨论了清管球滞留原因;从建立较大背压发球、增加清管球过盈量、改变三通倾斜方向3个方面来研究解决问题的方法,证明均不符合实际情况;通过对比清管球、皮碗清管器、泡沫清管器3种设备的优缺点,最后选择泡沫清管器为北内环清管最优的清管器材。     

输油站场清管系统应力分析

清管是输油管道重要的常规作业之一,是保证管线长期按照设计输量运行的重要保障。目前,对输油站场的清管系统在运行工况下的应力分析较少,特别是没有考虑由于清管器本身对管道所造成的冲击对管道应力分布的影响,所以有必要对输油站场清管工况下的管道进行应力分析。文中采用CAESAR Ⅱ软件对某输油站清管工况下管道系统进行应力分析,建立了清管器受力模型,通过编制VB程序计算了清管器的冲击产生的集中应力大小,并以假设清管器产生的冲击力最大的情况下得出整个管道的一、二次应力分布,找出了一、二次应力分布的关键点,并进行了校核,满足管道的强度要求,所用方法有利于更好地保证清管作业安全。     

清管器两种工作机制对清管效果的影响

文中研究了清管器在不同长度的原油及天然气管道中的清管效果,以及清管器在长输管道中的工作原理,分析了提高清管器工作效率的理论依据。结果表明:清管器在清管过程中存在机械清洗和泄流清洗两种工作机制,清洗的效果主要取决于清管器的机械清洗能力,通过改变清管器的组装方式可以将清管效果提高1～2个数量级。     

长距离高压管道清洗技术研究

文中通过PIG清管技术在长距离高压管道的应用,介绍了由电子定位跟踪装置、清管器、收发球等组成的PIG清管系统。分析了清管系统运行情况,对该系统在长距离高压管道清洗中可能出现的问题提出解决方案,为长距离管道清洗提供整套方案。     

JZ25-1S油田混输海管清管过程模拟分析

采用多相流瞬态模拟软件OLGA,对JZ25-1S油田的WHPB平台至CEP平台油气混输管道进行了清管过程模拟分析,模拟得到了清管球在管道内的运行位置及速度。通过模拟分析清管过程中,管道起终点压力、上升立管底部压力、终端流型、终端液体流量、累计液体量及清管前后管道中总持液量随时间的变化,得到了清管过程中管道起终点的最大压力、终端液体流量的最大值、累计液体量等。利用这些数据判断清管时段塞对管道及下游设施的影响程度,为今后该海底油气混输管道清管过程的理论及现场清管操作提供指导。     

Analysis of factors affecting the choice of route of pedestrians

Pedestrians as compared to vehicular traffic enjoy a high degree freedom of movement even in heavily congested areas. Consequently, there are more alternative links available to pedestrians between a given origin‐destination (O‐D) pair. This paper describes a study done by the University of Calgary to evaluate the factors affecting the choice of route on intra‐CBD trips or trips within the Central Business District (CBD).

An origin destination survey conducted in downtown Calgary, Alberta enabled the identification of the most significant factors influencing the choice. These factors were analyzed in relation to the physical characteristics of the location, personal characteristics of the trip maker and the type of the trip.

It appears that most people chose the shortest link and factors such as the level of congestion, safety or visual attractions were only secondary. This suggests that the length should be made a major consideration when planning and designing pedestrian links.     

Non-parametric analyses of efficiency of airports

This paper estimates the efficiencies and productivity changes of 12 international airports in the Asia-Pacific region based on data from 1998 to 2006. We apply stochastic frontier analysis (SFA) to compute efficiency estimates and use the Malmquist productivity index (MPI) to analyze productivity changes. We use the SFA model with a translog-type production function after testing the statistical hypotheses. According to the results of the SFA hypothesis tests, airports have experienced a technological regression; the deviations from the efficiency frontier are caused more by technical inefficiency than random noise. However, the inefficiency was found to decrease. The MPI reveals a declining trend resulting more from technological change than from efficiency change, with a decrease in inefficiency. Taken together, both the hypothesis tests and the MPI not only provide consistent conclusions, but also suggest that airports should concentrate on technological progress.     

波纹管应力分析研究进展

评述了波纹管应力理论研究方法的进展情况，围绕解析法、工程近似法和数值法，对波纹管理论研究中的一些主要成果作了较详细的回顾和总结，对各种研究方法作出了评价，展望了亟待解决的一些问题。     

实现多组态计量软件集中监控的可行性分析

天然气自动计量系统有多种组态软件,由于软件的不相通性,造成了计量系统数据采集的通用性差、数据传输与入库的时效性差、数据利用的可靠性低.结合各组态软件的实际情况,从设计上充分利用Oracle大数据处理能力以及Partition(分区表)的特性,实现历史数据的存储,应用WebService与COM+数据访问组件提供多层数据访问架构,采用OPC与DDE工业数据交换协议,实现了各站场计量数据的实时上传,为连续数据采集和实时监控提供了可能,节约了改造成本.     

注汽管道承压能力评估和实物试验验证

基于失效评估图技术对某注汽管道进行了承压能力评价,给出了管线在不同腐蚀壁厚情况下的极限承压能力和极限裂纹尺寸。并利用实物爆破试验验证了评价方法的安全性和有效性,通过对爆破断口进行宏观和微观分析,发现管段的开裂属于脆性开裂。     

输油管道中原油乳状液的流变性研究

原油乳状液的流变性是原油开采后在管道中输送的重要研究方面,为了更好地研究这一性质,采用电动搅拌机、偏光显微镜以及流变仪等仪器来测定不同含水率的原油乳状液在不同条件下的黏度,观测不同含水率的原油乳状液在偏光显微镜下的形态。并且分别对原油乳状液的黏度与含水率之间的关系以及与剪切速率之间的关系进行研究,初步确定了所测区块原油乳状液的转相点以及该区块原油乳状液的流变特性,为生产中的油气集输提供了理论依据。     

城市轨道交通杂散电流监测系统概述

介绍了城市轨道交通工程中杂散电流不同的监测系统的构成,分析了集中式、分散式和智能型等监测系统的配置和功能,以及智能型实时在线监测系统的重要意义,为轨道交通工程杂散电流监测系统的选择与应用提供参考。     

埋地管道防腐保温层失效评价

明确埋地管道防腐保温层的技术评价标准,对埋地钢质管道的安全运行,延长管道使用寿命具有重要意义。为了对埋地管道防腐保温层做出有效评价,从间接检测与开挖检测2个方面,结合现场检测数据,提出了基于防腐保温层的电流衰减率、绝缘电阻率、质量状况与厚度的分级评价标准及基于4种评价指标的综合评判方法。工程实践表明,该评价标准对防腐保温层是否存在失效能做出有效判断。     

Preliminary results of an analysis of areas of influence in Shanghai

The main deficiency of most current modeling approaches to transportation can be identified as neglect of the integration of existing geographical knowledge in regard to the ex ante transport/land use modeling approaches, with its focus on territorial dynamics and theory development. This paper addresses this aspect of the problem by introducing a theoretical and methodological framework for the analysis of the interrelationship between land uses. The analysis attempts to determine to what extent the functional land use in a city can be considered an ordered pattern. The order sought does not rely on purely spatial configurations, but on the correlation of transportation and land use. The first section of this paper focuses on theoretical considerations. It stresses the fact that conventional approaches do not apply in the present context. It then suggests an alternative based on areas of influence and measured in terms of level of attractance of land uses. The second describes a procedure based on this alternative following the remarkable contribution of Hanjoul, Beguin and Thill. An application of this procedure to the analysis of Shanghai is then examined. Finally, an evaluation of the strategies for optimizing the interrelationship between land uses is presented. The paper concludes with a possible research agenda.     

Direct analysis of the perceived importance of attributes of reliability of travel modes in urban travel

Reliability of travel modes was found to be the most important characteristic of transportation systems in several attitudinal investigations of individual travel behavior. This paper represents the first part of a research effort aimed at gaining a better understanding of the characteristics of reliability of transportation modes in urban travel. In this research, reliability characteristics are identified; their importance relative to each other is assessed, and an insight into possible structure of an objective reliability index is discussed. The research is based on perceived values of reliability, which were identified through a large attitudinal survey conducted in the Chicago metropolitan area.