The blend of propane, butane and pentane manner and the device null which are recovered from the gas which includes the light component due to other than the aforementioned each component

摘要

PCT No. PCT/FR84/00303 Sec. 371 Date Aug. 14, 1985 Sec. 102(e) Date Aug. 14, 1985 PCT Filed Dec. 26, 1984 PCT Pub. No. WO85/03072 PCT Pub. Date Jul. 18, 1985.The gas to be treated is cooled and partly condensed in two steps (3-4, 5-6), and the condensed fractions are distilled in a column (9). A part of the condensed liquid at the top of the column is subcooled in the second exchanger 5, expanded, and vaporized in counter-current to the gas to be treated. This permits the obtainment of cooling temperatures on the order of -80 DEG C. by means of a refrigerating unit (13, 20) operating at a temperature on the order of -30 DEG to -40 DEG C. Application to the recovery of a mixture of propane, butane and pentane from a petroleum refinery residual gas.