IGS系统讲座.ppt

IGS系统讲座 大连远洋运输公司船技部 马文华 关于IGS的几个定义 Inert gas-means a gas or a mixture of gases, such as flue gas, containing insufficient oxygen to support the combustion of hydrocarbons. Inert condition-means a condition in which the oxygen content throughout the atmosphere of a tank has been reduced to 8 percent or less by volume by addition of inert gas. Inert gas plant-means all equipment specially fitted to supply, cool, clean, pressurize, monitor and control delivery of inert gas to cargo tank systems. 4. Inert gas distribution system-means all piping, valves, and associated fittings to distribute inert gas from the inert gas plant to cargo tanks, to vent gases to atmosphere and to protect tanks against excessive pressure or vacuum. Inert gas system-means an inert gas plant and inert gas distribution system together with means for preventing backflow of cargo gases to the machinery spaces, fixed and portable measuring instruments and control devices. Inerting-means the introduction of inert gas into a tank with the object of attaining the inert condition Gas-freeing-means the introduction of fresh air into a tank with the object of removing toxic, flammable and inert gases and increasing the oxygen content to 21 percent by volume. Purging-means the introduction of inert gas into a tank already in the inert condition with the object of: .1 Further reducing the existing oxygen content; And /or .2 Reducing the existing hydrocarbon gas content to a level below which combustion cannot be supported if air is subsequently introduced into the tank. 9. Topping-up-means the introduction of inert gas into a tank which is already in the inert condition with the object of raising the tank pressure to prevent any ingress of air. 关于爆炸上/下限的简单介绍 通常来说，上/下限为碳氢化合物在空气中的含量为1%--10%（容积百分比） 请看图示 根据实验证明，氧气的含量（容积百分比）达到11%，即无爆炸危险，IMO组织规定为8%。 IMO关于IGS系统的相关规定 SOLAS II-2 Regulation 62 1 . The inert gas system referred to in regulatio