基于Fluent的海管内停输管内原油温度变化过程分析

Analysis of Oil Temperature Decreasing Trend in Shut Down Submarine Delivery Pipe Based on Fluent

海管是海上油气田开发的关键设施，其安全性必须得到保证。海管停输作业过程中，由于海水的冷却作用，导致管内原油温度降低，当原油温度低于临界温度时，将发生凝固现象，这将对海管的重新启动产生不利影响。因此，分析海管停输过程中，管内原油温降规律和凝固过程对于安全停输时间的设定、重启方案制定具有重要意义。本文利用FLUENT软件对海管停输温降过程进行了数值模拟，对比分析了保温层海管和裸管在停输过程中，原油温度的变化过程，算例中发现保温层能够延长海管原油的发生凝固的时间，裸管内原油出现凝固的时间比保温层海管内的少1／5；通过敏感性分析，讨论了保温层材料参数对管内原油温降过程的影响，结果发现，保温层热传导系数对原油温降过程影响远大于密度和比热。本文的结论对于海管停输温度场的分析、海管安全停输时间的设定、保温层材料的选择具有一定的参考意义.

As a key facility in offshore oil-gas development, the safety in operation of submarine pipe must be guaranteed. During the period that the submarine pipe is shat down, due to the seawater cooling effect, the temperature of crude oil in the pipe will drop. If the temperature is lower than critical temperature, the crude oil will be solidified, that brings adverse effect on restart operation. Therefore, analysis of temperature drop of residual oil in the submarine pipe during shutting down is of great significance to proprly setting shut down time and restart scheme. In this paper, temperature drop process during shutdown of submarine pipe is discussed using FLUENT. In the numerical example, a comparison between the pipe with insulating layer and the naked pipe is made. It is concluded that the time to start being solidified for the latter is less than 20% of the former. Through sensitivity analysis, it is found that thermal conductivity of insulation layer is a key factor influencing the heat insulation. The conclusion conducted in this paper provides a reference to the analysis of temperature drop process during shutdown, to the design of safe shutdown time period and to the choose of insulation layer material.