Excessive recirculation of inert gas is...

Excessive recirculation of inert gas is _________.

🔍 Key Concepts

• Inert gas system purpose – to keep oxygen content in cargo tanks below a safe limit (usually about 8% by volume, but verify in current regulations/ship’s manual) • Recirculation line function – what happens when you take inert gas from the stack/main and send it back through the scrubber/blower instead of to the tanks • Effect of high recirculation rates on gas quality (oxygen content, temperature, pressure) and equipment (e.g., deck water seal)

💭 Think About

• Think about what changes in the composition of the gas if you keep re‑using the same inert gas instead of continuously supplying fresh flue gas from the boiler uptake. • Consider which part of the system is designed to protect against over‑pressure of cargo tanks, and whether recirculation alone would realistically defeat that protection. • Ask yourself: which of these options directly contradicts the basic safety purpose of an inert gas system on a tanker?

✅ Before You Answer

• Verify what condition makes inert gas unsafe for tank inerting (focus on maximum allowable oxygen percentage). • Consider how cargo tank pressure is normally controlled (PV valves, deck isolating valves, stripping/suction) and whether recirculation changes that directly. • Check whether shipboard guidance or training materials ever describe excessive recirculation as “highly recommended” or as something to be avoided and why.

🔍 Key Concepts

💭 Think About

✅ Before You Answer