Purification method and purification system for propane

Abstract

[PROBLEM] To provide an industrially advantageous method and system that are simple and have superior energy efficiency for obtaining high-purity propane from low-purity propane. [SOLUTION] Water, carbon dioxide, at least one of ethane and propylene, and at least one of isobutane and normal butane present in low-purity propane in a gaseous phase are adsorbed by means of a zeolite molecular sieve that preferentially adsorbs water and carbon dioxide over propane, an activated carbon molecular sieve that preferentially adsorbs ethane and propylene over propane, and activated carbon that preferentially adsorbs isobutane and normal butane over propane. Propane is condensed in a state in which nitrogen and oxygen are maintained in a gaseous state by introducing the low-purity propane in a gaseous phase into a partial condenser. Nitrogen and oxygen in the gaseous phase are extracted from the partial condenser.