摘要
干空气干燥法是目前使用最广泛的天然气管道干燥方法,也是新建天然气管道干燥的首选方法。但由于干空气干燥时管道中同时存在传热和传质过程,而管道干燥时间却主要是根据干空气的进气端和出气端的平均露点降来计算,不能分阶段确定干燥过程和吸水过程的除水能力,据此确定的管道干燥时间与实际数据偏差较大。为此,分析了干空气干燥过程中露点的变化规律,合理划分了干燥过程的干燥、吸水阶段。基于干燥机理建立了干燥阶段的一阶非线性偏微分模型,并采用有限差分法和弦切法进行了求解;基于吸水机理建立了吸水阶段双曲线型偏微分模型,根据其固定的边界条件和初始条件,采用分离变量法及辛普森数值积分方法求解,获得了干空气干燥法分阶段的真实干燥时间计算方法。双庙1井—杨柳垭输气管道干燥工程的实例应用表明,该方法计算的管道干燥时间结果符合现场实际情况,可较好地指导现场管道干燥作业。
Dry air drying process is one of the most widely used methods for natural gas pipelines.It is also the first choice of pipe drying for the newly built gas pipelines.However,because both heat-transfer and mass-transfer processes exist in the pipeline during the drying process and the drying time mainly depends on the average dew point depression between the gas inlet and outlet,it is impossible to identify the dehumidifying capacity during the drying and water absorption process by stages and there will be a huge gap between the obtained pipeline drying time and the actual data.Therefore,this paper analyzes the changing rule of the dew points and divides the drying process into drying and water absorption stages.Based on the drying mechanism,a first-order nonlinear partial differential model for drying stage is established and solved with the finite difference method and the chord cut method.Based on the water absorption mechanism,a hyperbolic partial differential model is also established and solved with the method of separation of variables and the Simpson numerical integration method based on the fixed boundary conditions and initial conditions.Thus,the method for the calculation of actual drying time is obtained.The simulation models by stages are proved to be practical from the case history of the pipeline from the Shuangmiao well 1 to Yangliuya.
出处
《天然气工业》
EI
CAS
CSCD
北大核心
2011年第7期67-70,109-110,共4页
Natural Gas Industry
关键词
天然气管道
干空气
干燥过程
吸水过程
分阶段仿真
干燥时间
传热
传质
natural gas pipeline,dry air,drying process,water absorption process,simulation,drying time,heat-transfer,mass-transfer
