Hydrogen sulfide (H2S) precipitation incidents often occur during pigging operations in crude oil pipelines, which result in the leakage of H2S with a high concentration at the site and seriously threaten the life and health of workers. To identify the main cause of H2S precipitation, this study designs a crude oil pipeline experimental system by which pigging operations could be simulated according to the on-site pipeline configuration. In addition, this paper determines the conditions at which a large amount of H2S could be stripped in an elbow pipeline when N2 passes through the pig to contact the oil sample and pushes to return the oil compared with those in a straight pipeline. Furthermore, this paper analyzes the effect of the N2 injection rate on H2S precipitation under repeated N2 contact with oil samples. Finally, this paper develops an empirical formula presenting the relationship among the H2S concentration ratio and its various influencing factors, which could give immediate guidance to prevent the occurrence of similar accidents.

硫化氢（H2S）沉淀事件经常发生在原油管道的清管操作期间，导致现场高浓度H2S泄漏，严重威胁工人的生命和健康。为了确定硫化氢沉淀的主要原因，本研究设计了一个原油管道实验系统，通过该系统可以根据现场管道配置模拟清管操作。另外，本文确定了与直管相比，当N2通过清管器接触油样并推动返回油时，在肘管中可以去除大量H2S的条件。此外，本文分析了氮气反复接触油样后，氮气注入速率对硫化氢沉淀的影响。最后，