LNG 비상분리 커플링 분리 특성에 관한 연구

Abstract

Emergency release coupling is an essential safety component installed on loading arms and hoses during LNG(Liquified Natural Gas) bunkering, and is used to prevent mass leakage of LNG due to damage to pipes or pipe connections. When more than an allowable external force is applied to the bunkering line during LNG bunkering, male and female couplers quickly separate from each other to urgently block the flow of LNG. The structure of the emergency release coupling is composed of a coupler member, a fastening member, and a variable assembly, and fluid is supplied from the body side to the plug side. In the case of emergency separation, a separation force is applied to the operating sleeve, and if the operating sleeve moves more than a predetermined displacement, the ball is detached and the body and the plug are separated. Conventional emergency release coupling for LNG is a breaking bolt that breaks above a certain external force, connects and separates male and female couplers, and opens and closes the flow path with a flip-flap valve with a torsion spring. Some studies on flow analysis and structure analysis exist as prior studies on the working principle of emergency release coupling, but no studies have been reported on the separation characteristics of emergency release coupling for LNG, including the pneumatic quick coupler. Therefore, this study proposes a new emergency release coupling for LNG, which connects and separates male and female couplers by seating or dropping the ball in the groove according to a certain external force by a cable or hydraulic cylinder, and opens and closes the flow path with a poppet with a compression spring. The proposed emergency release coupling allows the male and female couplers to be continuously detached without replacing separate parts, allowing bunkering to resume quickly even after emergency separation, and excellent airtightness performance can be expected as the flow path is opened and closed by the poppet valve. We design a three-dimensional feature model and simulation model that can implement the aforementioned operating principles and perform a separation simulation with operating conditions to verify the separation characteristics and validity of the proposed emergency release coupling.