극저온용 유체기기 유압 구동장치 지지대 설계

Abstract

Recently, as eco-friendliness is an international trend, energy conversion is progressing worldwide. The International Maritime Organization (IMO) has enforced NO, CO, SO, and PM (Particulate Matter) emission regulations in the International Convention for the Prevention of Pollution from Ships (MAPOL, 73/78 ANNEX VI). This regulation tightened the standard for sulfur content of fuel oil in ships from 3.5% to 0.5%. Due to the tightened regulations on the marine atmospheric environment, the shipbuilding industry is building or renovating ships that use liquefied natural gas (LNG) as fuel for ships instead of conventional B-C oil (HFO), Marine Diesel oil (MDO), and Marine Gas Oil (MGO). Liquefied natural gas is liquefied by cooling down its temperature to 111.15K and making the volume ratio 1/600 compared to gas phase to use liquefied natural gas as fuel to facilitate storage and transportation of methane obtained by refining natural gas collected from gas fields. The mean effect is reduction in discharge of sulfur oxides, carbon dioxide, and nitrogen oxides. Natural gas is composed of methane, ethane, propane, butane and a small amount of heavy hydrocarbon compounds and impurities. Nitrogen and sulfur components, water, carbon dioxide, hydrogen sulfide, etc. may be present in the gas produced in the gas field, but are removed before liquefaction. Natural gas depends on the production area or production process, but methane is the main component and contains 87% to 99% of the total composition. Liquefied natural gas is transported in a cryogenic liquid state. Natural gas leakage causes suffocation and can lead to serious accidents due to flammable substances. Therefore, an emergency release coupling (ERC Emergency Release Coupling), which is an essential safety device, is installed on the loading arm and hose so that it can be quickly stopped when an emergency shutoff of liquefied natural gas is required during an emergency during LNG bunkering. There are three types of operation mechanism for emergency separation of the emergency release coupling: a hydraulic operation method capable of external and active operation, a cable operation method, and a dual operation coupling combining a method by a cable and a hydraulic operation method. At present, the core parts for LNG bunkering in the domestic market is depend on imported products, and there are no domestic development cases for emergency release coupling, which is an essential safety device. This study developed a heat transfer analysis model for the supporter of emergency separation coupling with ultra-low temperature hydraulic operation method installed in loading arms and hoses for LNG bunkering to block fluid flow. This analytical model is designed for the optimum supporter for ultra-low temperature couplings through heat transfer analysis according to the height, thickness and tightening method of the supporter.