Effect and mechanism of drainage measures on gas-liquid coalescence separation performance of a water mist filter

In natural gas transportation, gas-liquid coalescence plays a crucial role in preventing pipeline and equipment corrosion. However, the development of novel drainage layer structures for gas-liquid coalescence filter elements remains limited, and the impact of traditional drainage structures on filter performance is not yet well understood. In this study, an experimental platform was used to evaluate the effects of three different drainage structures on filter performance. Digital image processing techniques were employed to analyze the internal liquid distribution within the filter layers, investigating the influence of the drainage layer on liquid flow channels and elucidating its functional role in the filtration system. The experimental results indicate that the addition of the drainage structure led to a 16 % reduction in pressure drop and a 12 % improvement in separation efficiency. Furthermore, the grid-shaped drainage structure outperformed the woven net structure, demonstrating a quality factor twice as high as that of the woven net configuration. Additionally, placing the drainage layer in the middle of the filter enhances drainage efficiency. The drainage layer improves separation performance primarily by reducing the number of liquid flow channels, decreasing channel area, and increasing channel diameter.