Axial flow API 6D check valve for liquefied natural gas receiving station

A liquefied natural gas receiving station innovatively introduced axial flow API 6D check valves in its expansion project, which were used in the outlet pipeline of high-pressure export pumps. After being put into operation, the system pressure drop was significantly reduced, creating favorable conditions for high load export.

Traditional swing check valves experience significant resistance losses in low-pressure reducing media, and long-term operation can increase the energy consumption of the pump unit. Axial flow check valves adopt a streamlined flow channel design, with the valve disc moving along the centerline. When opened, it almost does not affect the flow direction of the medium, and the flow resistance coefficient is much lower than that of conventional structures. The valve is equipped with a spring assisted reset device, which can maintain the fully open position during normal operation of the pump unit, and the valve disc does not cause additional disturbance to the fluid.

The export conditions of the receiving station are complex and require frequent adjustment of the export volume. The check valve can maintain a reasonable opening at different flow rates, and the pressure drop changes smoothly. The operator found through comparison of products of the same specifications that axial flow check valves have lower pressure differential readings under the same operating conditions, which is beneficial for reducing the head demand of the pump unit.

The API 6D standard covers pressure drop testing methods and leakage levels for check valves, providing a fair platform for selection comparison. With the continuous improvement of LNG receiving capacity, the energy-saving design of high-pressure and high flow check valves is receiving increasing attention.

This successful application provides a reference for the selection of low-energy check valves in the design of subsequent receiving stations, promoting the development of the industry towards high efficiency and energy conservation.