Flue gas system
If available, flue gas from ship boilers can be used for inerting. The flue gas system washes and cools the boiler flue gas, and delivers it to the cargo tanks during cargo unloading and tank washing. As the flue gas already contains less then 5% oxygen no further treatment is necessary. This system is primarily used on crude oil tankers. The main components are: the scrubber unit, inert gas blowers, the deck water seal, the pressure/vacuum breaker, valves, instrumentation and the control system. Surplus gas is automatically re-circulated to the scrubber unit. The system can also be preset to deliver fresh air for gas-freeing purposes.