METHOD FOR RECOVERING/PURIFYING HELIUM GAS

摘要

PROBLEM TO BE SOLVED: To provide a helium gas recovering/purifying method for recovering helium gas at a high recovery rate by a simple operation without a large-sized apparatus such as a PSA (pressure swing adsorption) separator. SOLUTION: This helium gas recovering/purifying method comprises a step to continuously withdraw helium gas containing at least oxygen as impurities from an airtight vessel, a step to purify the withdrawn helium gas by permeating it through a gas separation membrane, and a step to circulate/recover the purified helium gas in the airtight vessel. The flow rate of an impermeable gas is controlled in the gas separation membrane so that the concentration of oxygen contained in the impermeable gas is kept constant. The concentration of oxygen in the impermeable gas is measured and the flow rate of the impermeable gas is controlled, so that the amount of the impermeable gas is made smallest and helium gas can be recovered continuously at a high recovery rate. COPYRIGHT: (C)2003,JPO