Abstract: Due to the constraints of upstream station processes, the KL gas pipeline often carries some hydrocarbon liquids during operation. Combined with the significant undulating terrain along the route, liquid accumulation is prone to occur in low-lying sections of the pipeline. This seriously threatens the stable and safe operation of the pipeline and downstream stations. Therefore, this paper proposes a method for predicting and analyzing liquid accumulation in wet gas pipelines. Based on HYSYS modeling, the composition data of the outlet gas is formulated with reference to the measured hydrocarbon dew point and water dew point of the outlet natural gas; phase analysis confirms the possibility of natural gas liquid condensation along the entire pipeline, with condensate oil dominating and condensate water being minimal. Combined with the analysis of the critical inclination angle for liquid accumulation in the pipeline, it is found that the critical inclination angle has gradually increased recently. Within the segment from the starting point to the 2# valve chamber, sections where the actual inclination angle exceeds the critical inclination angle in upward slopes along the gas flow direction are prone to liquid accumulation; even when the flow rate is increased to the design capacity, liquid accumulation cannot be completely avoided. The findings of this study can provide important reference for the production operation and safety management of this pipeline.

Key words: gas pipeline, pipeline liquid accumulation, dew point, natural gas liquids, critical inclination angle