输气管道投产置换注氮量计算方法

目前，国内管道投产置换过程中所需氮气量主要根据经验确定，存在较大的盲目性，导致天然气管道投产成本较高，安全风险较大。为此, 以长呼管道(长庆气田至呼和浩特市)为背景，对其投产置换过程中管道内空气段、氮气段和天然气段的紊流扩散情况进行了多工况数值模拟，并对模拟计算结果进行多参数拟合，从而推导出投产置换过程中气体混合段长度以及注氮量的计算公式。将计算结果与现场试验数据对比可以看出：提出的混合段长度和注氮量计算公式具有较好的预测准确性。

CALCULATION METHOD OF INJECTION CAPACITY OF NITROGEN IN DISPLACEMENT COURSE FOR COMMISSIONING OF GAS TRANSMISSION PIPELINE

Presently, the injection capacity of nitrogen for the displacement of air for pipeline commissioning is mainly determined according to experience, so there are great blindness, which will lead to high commissioning cost and risks for the natural gas pipeline. Therefore, taking the Pipeline from Changqing Gasfield to Hohhot as an example, the paper simulated the turbulence diffusion course of air, nitrogen gas and natural gas section at different working conditions during the displacement course for commissioning of the pipeline. The multi parameter fitting for the simulation results was performed. Then, the calculation formulas of the mixed section length and the injection capacity of nitrogen in displacement course were derived. Contrasting the calculation results with the on site trial data, this paper draw a conclusion that the calculation formulas of the mixed section length and the injection capacity of nitrogen put forward here are of favorable prediction accuracy.