Inert gas purging system for an orc heat recovery boiler

In one embodiment, a system includes a valve system (60) switchable between a waste heat recovery position configured to direct incoming exhaust gas (38) through an interior volume (60) of an exhaust section (28) of an engine (12) and a bypass position configured to direct the incoming exhaust gas (38) through a bypass duct (46) to bypass a heat recovery boiler (40) disposed within the interior volume (60). The system also includes an inert gas purging system (72) configured to inject an inert gas into the interior volume (60) to displace residual exhaust gas (38) from the interior volume (60).