Mechanics of offshore pipelines in several operating states and analyzing software

Offshore pipelines are indispensable structures during the marine petroleum exploitation. There are manifold operation states having to do with pipelines such as in situ operation, span, trenching, pipelaying, lifting of pipe/riser, etc. The behavior of pipelines in one state differs greatly from the others. In addition, the structure configuration, the sea severity, and the seabed soil conditions are complex. Therefore, strength analysis of offshore pipelines becomes a rather difficult and onerous task. Presently, there is a lot of technological difficulty in the course of analysis, among which are not only theoretical problems such as geometric non-linearity and moveable boundary, but also practical problems. To tackle the problems, analytical methods, numerical methods such as FEM and shooting method are adopted respectively and jointly. Based on the theoretical research, integrated software named 'Offshore Pipelines Strength Analysis' is developed. This software can carry through strength analysis of pipelines in different operating state, being up to the requirement of engineers. The theoretical background and interface of the software are presented

Nonlinear analysis of submarine pipelines during single point lifting

基于管道微单元体平衡建立了海管单点提升的非线性力学模型的控制微分方程组，使用变弧长的无量纲代换将动边界问题化为固定边界的两点边值问题，利用Maple环境下编制的两点边值问题的打靶法程序得到了该问题在各个提升阶段的数值解答和在单点提升过程中管道的极限弯矩约为0.71q~(1/3)(EI)~(2/3)

Mechanical analysis of pipelaying

海底管道铺设是近海工程建设中的重要环节。由于铺管问题的控制议程具有的非线性，加之边界可动，所以问题的求解比较困难。本文采用奇异摄动法较好地解决了这一问题，并与有限元解作了比较

Analysis of multi-point lifting of pipelines based on the interpolation function

建立海管点提升的力学模型，用多项式插值得到各种提升状态下的变形和内力.和现有方法相比，该法编程简单，易于实现，能满足工程的计算精度

Strength of Offshore Pipelines in Different Operation States and Analyzing Software

在近海管线的铺设、安装、使用过程中有多种作业状态：在位、悬跨、挖沟、提吊、铺管等。各种状态下管线的受力特点不同，加上管线结构、海况和海底土壤等因素又都很复杂，所以近海管线的强度分析难度大、内容多。分别采用解析方法、数值方法（有限元法、打靶法）和二者结合来解决理论上的（如几何非线性、动边界等）、实用性方面的难点。在理论分析的基础上，编制了符合产业部门工程师使用要求的近海管线强度分析软件。介绍了该软件进行力学分析时采用的理论以及软件界面

海底管线强度评估中的两个问题

海底管线是海上油气田生产设施的重要组成部分,它一旦发生破坏会在各方面引起重大损失.挖沟和提吊引起应力超标是海底管线两种重要的破坏形式.挖沟和提吊问题的难点是:1)二者都是动边界问题,悬空长度本身就是未知量;2)挖沟问题中应考虑台阶升高处土壤支持的弹性影响(这比刚性处理更准确,但这会使边界条件更复杂);3)提吊是一个几何非线性问题,求解难度较大.本文给出挖沟和提吊作业状态下,海底管线的强度分析方法.在挖沟分析中,采用线性梁理论,将台阶升高处的土壤支持处理为线性弹簧.在提吊问题中,将管线模型化为大位移梁,采用打靶法,将边值问题转变为初值问题求解.文中还给出有关的典型数值计算结果

车用生物燃气工程范例余热定量评估及可利用性分析

针对车用生物燃气工程能耗高、余热利用率低的问题,该文以国内4个典型工程为基础,构建了产气规模为1万m3/d的示例工程,并对其进行余热分析。分析结果显示,此类工程用能量大,占总产能的30.01%-36.44%;余热利用率低,只有部分贫液余热得以回收;系统余热主要由脱碳塔顶气余热、脱碳贫液余热、压缩机余热、沼液余热和锅炉尾气余热5部分组成,其多为低品位余热、量大稳定。余热计算表明,在最冷月和最热月系统余热潜力分别为5.87×104、4.79×104 MJ/d,最大节能潜力分别为74.81%和73.92%,节能潜力降序排列为沼液余热〉贫液余热〉塔顶气余热〉压缩机余热〉锅炉余热。余热可利用性分析认为工程余热可利用性较高,回收价值较大

Quantitive estimation and availability analysis of waste heat from vehicle biogas plant

针对车用生物燃气工程能耗高、余热利用率低的问题,该文以国内4个典型工程为基础,构建了产气规模为1万m3/d的示例工程,并对其进行余热分析。分析结果显示,此类工程用能量大,占总产能的30.01%-36.44%；余热利用率低,只有部分贫液余热得以回收；系统余热主要由脱碳塔顶气余热、脱碳贫液余热、压缩机余热、沼液余热和锅炉尾气余热5部分组成,其多为低品位余热、量大稳定。余热计算表明,在最冷月和最热月系统余热潜力分别为5.87×104、4.79×104 MJ/d,最大节能潜力分别为74.81%和73.92%,节能潜力降序排列为沼液余热〉贫液余热〉塔顶气余热〉压缩机余热〉锅炉余热。余热可利用性分析认为工程余热可利用性较高,回收价值较大