地表夯击载荷作用下埋地管道力学分析

为研究地基强夯作业中夯击载荷对埋地管道力学性能的影响,基于有限元原理建立了夯锤-管道-围土耦合三维模型,分析了夯击过程中管道截面变形及所受冲击力变化规律,研究了管道壁厚、夯击速度、夯锤体积对管道应力、应变及变形的影响规律。结果表明:夯击载荷下的管道所受冲击力为脉冲型,且随时间推移逐渐降低为0,最大冲击力随管道壁厚、夯击速度、夯锤体积增大而增大;管道最大等效应力、高应力范围及最大等效塑性应变随壁厚增加而减小,但随夯击速度或夯锤体积增大而增大;随着夯击速度、夯锤体积增大,管道截面变形率（椭圆度或凹陷率）逐渐增大,但其随壁厚增加而减小。     

天然气气田开发中钻井与集输管线工程环境监理浅议

天然气气田开发工程属生态影响类建设项目,其中以钻井工程和集输管线工程对环境影响最大,其特点是：污染物种类复杂,环境影响时间长,影响范围广,生态扰动大。本文结合某大型天然气气田开发工程环境监理的工作实践,归纳总结了钻井工程和集输管线工程的特点,并针对工程实施过程中存在的主要环境问题,着重分析了开展工程环境监理的重点工作内容。     

输油管道弯头穿孔泄漏数值模拟

我国在役输油管道经过多年冲刷及腐蚀后,存在安全隐患,使得对输油管道泄漏事故的研究具有重要的现实意义。基于计算流体力学方法,采用有限容积法,建立管道泄漏控制方程,研究不同输送速度及泄漏孔径对泄漏后管内压强分布及泄漏量的影响。结果表明:泄漏孔径一定,输送速度分别与管内压强和泄漏量成正、负相关,泄漏口下游存在局部高压区;输送速度一定,泄漏孔径分别与管内压强和泄漏量成负、正相关,局部高压区的强度降低、范围减小。实际工作中可以采用一定方法增大管内输送速度或增大泄漏口径,从而减少实际的原油泄漏量。     

污染地下水原位治理技术--透水性反应墙法

20世纪90年代初期在美国和加拿大兴起的原位被动修复技术--透水性反应墙,是一种地下水污染原位处理方法.其通过在垂直于地下水流动方向设置活性渗滤墙,当地下水流通过活性渗滤墙时,污染物与墙体材料发生化学反应,从而达到环境修复的目的.该技术具有原理简单,施工方便,能持续原位处理,处理组分多,且运行费用低廉等特点,能有效吸附和降解多种重金属和有机污染物.该方法目前在欧美已开始进入广泛的工程应用阶段,正逐步取代运行成本昂贵的抽水处理技术,成为地下水修复技术的发展方向.系统介绍了透水性反应墙法,阐述了反应墙的类型、活性材料的选取、反应机理、反应墙的构建以及应用实例,同时分析了其存在问题并展望其今后的研究方向.     

埋地阴极保护管线的交流干扰腐蚀

通过阴极保护管道交流腐蚀案例,总结了交流输电线路等交流设施对埋地管道的干扰规律、阴极保护管道交流腐蚀的特征、发生条件及影响因素等.综述了交流电对管道钢材料活化和钝化体系的电极过程和极化行为的主要影响规律;高阴极保护水平对交流腐蚀的协同加速作用.系统阐述了阴极保护条件下管道发生交流腐蚀的机理及评估准则等方面的最新研究进展...     

高压直流输电系统对埋地管道干扰及防护研究进展

为了让相关人员更好地了解高压直流干扰领域研究现状,通过对国内外相关领域研究成果的总结,介绍了高压直流输电系统接地极和线路对埋地管道干扰的产生方式,分析了高压直流干扰对埋地管道的危害类型、评价指标研究现状以及现有防护措施的类型和优缺点.在此基础上,总结了目前该领域的研究重点和难点,指出了未来高压干扰问题的发展方向,为相关...     

穿越城市生活区的天然气管道泄漏连锁爆燃后果评估研究

为评估城市天然气管道泄漏连锁爆燃事故后果,基于计算流体力学(CFD)方法构建穿越城市区域的天然气管道泄漏连锁爆燃后果预测与评估模型,以某城市生活区域为例,在城市生活区域建筑物内风场流动计算的基础上,模拟风场作用下可燃气体在城市建筑物空间内的运移规律,预测可燃气云的积聚区域;考虑意外点火的情况,计算城市生活区域内可燃气云爆燃灾害特征,预测爆燃超压、热辐射和高温的影响。研究结果表明：由于建筑物之间的阻挡与反射作用,建筑物下风向有明显的低风速区域,并在一定时间段后扩散过程趋于稳定;在爆燃火焰作用下,高温和热辐射会造成建筑物部分钢结构发生失效变形。     

Experimental research of the dynamic behavior of the natural gas suspension pipeline aerial crossing during pigging process

Suspension pipeline aerial crossings (SPAC) are mainly used to carry pipeline segments over large obstacles that are not suitable for trenchless technologies. It may suffer great vibrations and displacements during the pigging process due to the dynamic pigging loads and insufficient constraints from cables. Based on similarity criteria, an experimental scale model based on the Nujiang natural gas SPAC was designed and established. The vibration and displacement of the scale model were measured under different pigging velocities and liquid deposit volumes. The experimental results reveal that the natural gas SPAC vibrates during the pigging process, but the displacement versus time forms a U curve instead of a sinusoidal like curve. The extremum of the displacement is positively related to the pigging velocity and liquid deposit volume. In particular, the extremum increases by 0.37% with a 1% increase in the pigging velocity, while the displacement increases by 0.62% with a 1% increase in the liquid deposit volume. Under certain pigging conditions, or with damaged constraint components, the displacement extremum could be unacceptable. A low pigging velocity and a short time interval between two pigging operations are suggested to guarantee the safety of the natural gas SPACs. Besides, based on the experimental data, an empirical formula is developed to obtain the SPAC displacement-time curve with consideration of the span length, the pipeline diameter, the pigging velocity, the length and holdup of the liquid column. This formula can help to determine a suspicious displacement overrun, and to develop a data basis for choosing a safe pigging scheme of SPACs. This research provides insightful information to understand the mechanism of the SPAC's dynamic response as well as a practical tool to calculate the SPAC's displacement during the pigging process.     

智能管道时代的管道风险评价技术展望

当前管道风险评价工作普遍使用半定量方法,通过对该方法的应用现状进行总结分析,得出目前半定量风险评价方法存在的问题,包括录入数据准确性不足、评价结果准确性不高,时效性不强等。通过分析物联网、智能移动终端、云技术、大数据等技术开始在管道的应用前景,展望了智能管道时代管道风险评价发展方向:实现管道风险评价实时动态评价,提高风险评价结果的准确性,实现风险的预测预警等,为未来管道风险评价技术发展提供研究思路。     

Modelling ice and wax formation in a pipeline in the Arctic environment

In the Arctic environment, the fluid temperature in the pipeline can drop below the freezing point of water, which causes wax and ice to form on the pipeline surface. Solid formation on the pipeline surface can lead to flow assurance and process safety issues, such as blockage of the pipeline, pipeline component failure, and release of hazardous liquid. Remediating the plugging requires a shutdown of pipeline operation, which incurs tremendous cost and delays the entire production system. In order to prevent blockage, the pigging operation can be used to remove the deposits on the pipeline surface on a regular interval. Ice and wax depositions in the pipeline are a slow process. However, if the deposition grows too thick, pipeline blockage can still occur after pigging operation. So, ice and wax deposition rates are required to be estimated accurately. This paper investigates ice and wax deposition rates in a 90,000 m pipeline. A fundamental model for both ice and wax deposition is proposed using the first principles of heat and mass transfer.