Separation of high velocity wet gas by phase-isolation and split-flow method

•A new method and separator for removing liquid in high velocity wet gas from pipeline are proposed.•The swirler of four semi-elliptic guide vanes can achieve a stable and uniform swirling core-annular flow.•Most part of gas core could be bypassed by split-flow method.•With the increase of RLW height, the change rules of the splitting ratio KS and separation efficiency are studied.•The effect of gas velocity on separation efficiency with different RLW height is studied. This paper proposes a new method for directly removing the liquid in wet gas from pipeline, especially for high velocity flow condition. The separation apparatus to be used is simply formed by enclosing a short section of the pipe with a compact cylinder and installing a swirler at the entrance. As gas–liquid mixture flows through the swirler downwardly, a strong swirl flow is created. Due to the centrifugal force, the two phases are isolated, forming a so-called swirling core-annular flow. Then a large portion of the gas core directly flows out of the separator, only the liquid film and a small portion of gas core (the conveying gas) enter the annular separation space through the upper portion of the ring-like window (RLW) in the pipe, where the conveying gas is separated from the liquid by centrifugal and gravitational forces and returns to the pipe through the lower part of the RLW. Numerical and experimental investigations were carried out in this study to determine the behavior of separation. The simulation and experimental results showed that the height of RLW has a strong effect on the behaviors of the separation, the conveying gas flowrate and the separation efficiency increase with the increase of RLW height, but the pressure drop also increases simultaneously. The separation efficiency even could approach 100% when the height of RLW is more than 1.5 pipe diameters with a 60% of conveying gas.