天然气管道中缓蚀剂浓度和保护距离计算公式及现场检验

FORMULAS FOR CALCULATING THE CORROSION INHIBITOR CONCENTRATION AND PROTECTION DISTANCE IN GAS PIPELINE AND THEIR FIELD EXAMINATION

通过借用和修正Ｌｏｎｇｗｅｌ的雾化浓度公式，得出了天然气管道中缓蚀剂雾化浓度分布公式；然后利用在四川石油管理局输气公司实验场测试的数据修正了浓度分布公式中的有关待定常数；最后利用现场输气管道实际运行数据检验了浓度分布公式。结果平均误差在１７％左右，基本满足工程要求。利用这些公式分别计算了实验场及现场管道的缓蚀剂沿轴和径向的浓度分布，其分布状况与实际经验相符。同时提出了缓蚀剂预膜时间及保护距离计算公式，利用这些公式计算了实验场及现场管道缓蚀剂预膜时间及保护距离。所得出的预膜时间及预膜量计算公式，目前还缺乏实验数据检验，但其理论推导是严密的，具有一定的可靠性。在满足公式要求的条件下，可以用于现场工程计算。

By using and modifying the Longwell formulas of mist concentration, the formulas for expressing the mist concentration distribution of corrosion inhibitor in gas pipeline are obtained, then some unfixed constants in the formulas are modified by the data tested in the experimental pipeline in Gas Transportation Corporation of SPA, finally the formulas are examined by the field data of pipeline operation. The mean error of examination is about 17%,which basically meets the requirements of engineering. The axial and radial distributions of corrosion inhibitor concentration in experimental pipeline and field pipeline are calculated respectively according to these formulas and the results are concordant with practical situation.The formulas for calculating the pre filming time and protection distance of corrosion inhibitor are proposed and the pre filming times and protection distances of the experimental and field pipelines are calculated by use of these formulas which are not examined by the experimental data now. But their theoretical derivation is strict and reliable. These formulas can be used in engineering calculation under the condition of meeting their requirements.