After the installation of the purging process pipe system, air purging or steam purging can be used according to the service conditions of the working medium and the dirt degree of the internal surface of the pipe. The large compressor of the production unit or the large container in the unit can be used for intermittent air purging. The purging pressure shall not exceed the design pressure of vessels and pipelines, and the flow rate shall not be less than 20m/s. The steam purging shall be carried out with large flow of steam, and the flow rate shall not be less than 30m/s.