Patent ID: 7043938

Claim:
A method for removing frozen material from at least one section of a multiple section cryogenic unit without shutting down said unit comprising introducing at least one flushing agent at least one time into said at least one section to melt said frozen material, said flushing agent being a liquid with a freezing temperature below the operating temperature of said at least one section, said flushing agent being at a temperature sufficient to melt said frozen material and remove same from said at least one section, introducing at least once at least one purge gas to remove part of said flushing agent, said purge gas having a temperature of vaporization such that it will not condense to liquid at the temperature of said at least one section after flushing, and introducing at least one time into said at least one section at least one solvent that is miscible with said flushing agent, said solvent having a freezing temperature below the operating temperature of said at least one section.