A method includes monitoring a pressure of a gasification system after gasifier shutdown via a pressure sensor, wherein the gasification system includes a gas treatment system and a gasifier configured to output syngas to the gas treatment system during gasification. In addition, the method includes depressurizing the gasification system after gasifier shutdown by opening a flare valve to release gas from the gasifier and the gas treatment system to an atmosphere. The method also includes pressurizing the gasification system after gasifier shutdown, when the monitored pressure reaches a lower pressure threshold, by establishing multiple purge flows of inert gas into the gasification system to remove residual gas from the gasification system. The multiple purge flows are established at different times and at different locations within the gasification system relative to each other.