Method for cleaning high-pressure gas container

Abstract

A method for cleaning a high-pressure gas container includes a depressurization step of reducing the pressure in a high-pressure gas container until the internal pressure reaches 5 Pa or less and a cleaning step of cleaning the inside of the high-pressure gas container after the depressurization step. The cleaning step includes a hydrogen halide supply stage of supplying a hydrogen halide to the high-pressure gas container after the depressurization step, a metal oxide removal stage of reacting, in the high-pressure gas container after the hydrogen halide supply stage, a metal oxide on the inner face of the high-pressure gas container with the hydrogen halide supplied in the hydrogen halide supply stage to form water, and a discharge stage of discharging the water formed in the metal oxide removal stage and the hydrogen halide supplied in the hydrogen halide supply stage from the high-pressure gas container.

Dependencies are inferred from the claim text.