天然气输气站场的风险评价技术研究

天然气输气站场的风险管理技术研究是风险管理中的一个崭新的领域.以风险理论和风险评价模型为基础,结合国内天然气输气站场设计、施工、运行时的工况,遵循国内站场技术标准和安全规范,建立了输气站场的风险管理模型,从9个部分对输气站场进行评价,提出站场风险标准及可接受性准则,给出风险控制的建议.     

油气集输联合站设备风险模糊综合评价模型

油田联合站设备的风险评价,对提高其安全技术水平具有重要意义.根据国内油田联合站设备的安全技术规范和功能特性,提出了联合站设备风险评价的模糊综合评价模型,建立较全面的联合站设备风险影响模糊失效可能性因素体系和模糊失效后果因素体系,制定出较客观的联合站设备失效可能性因素及失效后果因素评价的方法.     

利用SPS模拟川气东送管道压气站失效问题

为研究压气站失效与单台机组失效对输气管道的影响程度,采用SPS软件对压气站失效和单台机组失效进行了详细模拟。模拟结果显示:压气站失效与单台机组失效相比对管输系统影响较大;对于压气站失效,越靠近末站的压气站失效对管输系统影响越大;对于单台机组失效,越靠近首站的压缩机失效对管输系统影响越大。分析结果可为事故状态下的供气和抢修提供参考。     

双螺杆式空气压缩机温高故障分析

府谷压气站采用INGERSOLL-RAND SSR-ML 45D型螺杆式空压机。文中引入螺杆式空压机的工作原理,分析了空气系统的作用及设备现状。温度过高故障是空压机的一种多发故障。文中以风冷式7.4立方机型为例,对润滑系统及油路元件、冷却系统、空气吸程和排程及控制管路元件等部分导致双螺杆式空气压缩机温高故障的原因进行了分析,提出了相应的解决办法及预防措施。深入研究将大大减少机组故障的发生,从而保证输气生产的安全进行。     

长输天然气管道压气站场控制系统整合的研究

长输天然气管道压气站场控制由站场控制系统和压缩机控制系统组成,两部分控制系统通过通讯连接将数据传输至调控中心和站场PLC,但站控系统和压缩机控制系统、压缩机控制系统和辅助系统相互独立,这是目前压气站场控制的普遍模式。通过将单台压缩机组与相应辅助系统控制进行整合、与全部机组相关的生产辅助系统同站控系统进行整合,整合后的压气站场由原有的三部分控制调整为站控系统PLC统一监视控制。控制系统整合将分散的控制功能集中,站场内全部设备实现远程操作,数据、故障集中监视方便问题处理,同时减少了冗余设备。     

管道输气系统的模拟研究

分析了天然气长输管线系统的实际运行规律,建立了带压气站的长输管线静、动态混合数学模型,并对其进行求解,得出长输管线一般的运行规律.     

大口径管道站场工艺安装预制化的应用

针对西气东输靖边压气站的扩建施工,介绍了施工图的分解,管道的预制与安装,以及在顸制中出现的问题及解决方法.通过采用预制化工艺,确保了扩建工程的质量和施工进度.     

在役输气管线的完整性评价方法

引入国外发展较好的完整性评价技术,从影响在役输气管线完整性的各种因素着手,对在役输气管线的完整性评价从安全性、可靠性和风险性3个方面进行分析。管道完整性评价是将3种评价方法有机结合起来,深入研究将大大减少管道事故的发生,并减轻事故造成的后果,从而为在役输气管线的完整性管理提供可靠的依据。     

长距离输气管道的最优输量研究

对已建成的长距离输气管道,可通过增设压气站的方法来增加管道的输量,随着压气站数的增加,管道的输量增大,管道的经济效益增加,但当输量增大到一定值时,管道的经济效益要降低,因此,长距离输气管道存在着一个使管道的经济效益最大的最优输量。以内部收益率为评价指标,分别计算各个方案的内部收益率,作出内部收益率与管道输量的关系曲线,内部收益率最大的方案所对应的输量就是长距离输气管道的最优输量。最后以一条输气管道为例进行了实例计算。     

枝状天然气管网流动方程

过去使用的关联矩阵方法在描述枝状天然气管网流动方程时,没有考虑压气站的自耗气,这在一些需要准确描述这部分气量的模型中会产生不可避免的偏差.文中通过增加自耗气源向量的方法对此进行了改进,使得该方法可以完整地描述这部分天然气,能更加准确地对管网的结构和流动方程进行描述.     

Risk‐based stochastic equilibrium assignment model in augmented urban railway network

This study developed a methodology to model the passenger flow stochastic assignment in urban railway network (URN) with the considerations of risk attitude. Through the network augmentation technique, the urban railway system is represented by an augmented network in which the common traffic assignment method can be used directly similar to a generalized network form. Using the analysis of different cases including deterministic travel state, emergent event, peak travel, and completely stochastic state, we developed a stochastic equilibrium formulation to capture these stochastic considerations and give effects of risk aversion level on the URN performance, the passenger flow at transfer stations through numerical studies. Copyright © 2012 John Wiley & Sons, Ltd.     

Locating rental stations and bikeways in a public bike system

To determine the spatial distribution of rental stations and bikeways in a public bike system, this paper proposes a facility location and network design model. The model is developed as a multi-objective programing problem that considers four objectives (minimizing cyclist risk, maximizing cyclist comfort, minimizing adverse impacts on traffic and maximizing service coverage) and multiple constraints (monetary budget, network connectivity, station spacing, bikeway types, station number and value ranges of decision variables). The ε-constraint method solves the programing problem for the public bike system in Daan District, Taipei City, Taiwan. The nine non-dominated alternatives generated are all markedly better than existing locations of rental stations and bikeways. Scenario analysis results indicate that increasing the construction budget for bikeways significantly improves cyclist safety and comfort whilst increasing the adverse impact on traffic. Planners can use this model to develop public bike systems that spatially integrate rental stations and bikeway networks.     

天然气站往复式压缩机活塞失效分析

针对天然气站往复式压缩机活塞的断裂事故,运用失效分析方法,开展了活塞断口扫描电镜分析、能谱和金相分析。根据断口形貌的电镜和金相观察结果,结合理论知识,分析确定了该活塞发生断裂事故的主要原因,即在特定工况下该活塞的材料缺陷是造成断裂的主要因素。     

Evaluating critical lines and stations considering the impact of the consequence using transit assignment model ‐case study of London's underground network

As the problem of full transit vehicles is encountered daily by passengers in most of the big cities, previous research evaluated the consequence of overcrowding in terms of on‐board crowding and passengers not being able to board with full vehicles. The impact of overcrowding in the real world is, however, not necessarily proportional to these numbers. This paper attempts to specify the critical lines and stations of a network by considering the number of passengers failing to board and attempting to evaluate its impact on service quality and safety risks. The hypothesis is that larger stations with wider platforms can often cope better with overcrowding than smaller stations. Therefore a station size dependent satisfaction function is proposed, which takes values from 0 to 1. The method is applied to London's underground network with a number of scenarios which show critical stations in the network if delays occur.     

A hierarchical line planning approach for a large-scale high speed rail network: The China case

Planning a set of train lines in a large-scale high speed rail (HSR) network is typically influenced by issues of longer travel distance, high transport demand, track capacity constraints, and a non-periodic timetable. In this paper, we describe an integrated hierarchical approach to determine line plans by defining the stations and trains according to two classes. Based on a bi-level programming model, heuristics are developed for two consecutive stages corresponding to each classification. The approach determines day-period based train line frequencies as well as a combination of various stopping patterns for a mix of fast trunk line services between major stations and a variety of slower body lines that offer service to intermediate stations, so as to satisfy the predicted passenger transport demand. Efficiencies of the line plans described herein concern passenger travel times, train capacity occupancy, and the number of transfers. Moreover, our heuristics allow for combining many additional conflicting demand–supply factors to design a line plan with predominantly cost-oriented and/or customer-oriented objectives. A range of scenarios are developed to generate three line plans for a real-world example of the HSR network in China using a decision support system. The performance of potential train schedules is evaluated to further examine the feasibility of the obtained line plans through graphical timetables.     

Optimal design of electric vehicle public charging system in an urban network for Greenhouse Gas Emission and cost minimization

In this paper, we address the optimization problem of allocation of Electric Vehicle (EV) public fast charging stations over an urban grid network. The objective is to minimize Greenhouse Gas Emissions (GHG) under multiple constraints including a limited agency budget, accessibility of charging stations in every possible charging request and charging demands during peak hours. Additionally, we address bi-criteria problems to consider user costs as the second objective. A convex parsimonious model that depends on relatively few assumptions and input parameters is proposed and it is shown to be useful for obtaining conceptual insights for high-level planning. In a parametric study using a hypothetical urban network model generated based on realistic parameters, we show that GHG emissions decrease with agency budget, and that the reductions vary depending on multiple factors related to EV market and EV technologies. The optimal solutions found from the bi-criteria problems are shown to be close to the solution minimizing GHG emissions only, meaning that the emission minimizing policy can also minimize user costs.