Recovering gases from a halocarbon composition

Halocarbons, such as refrigerants, are cooled to liquefaction and so freed from gases such as nitrogen which do not so readily condense. An apparatus for performing the process comprises a heat-exchanger 170A filled with a heat-transfer liquid 170L (preferably denatured alcohol) surrounding a collection tank 170B. The mixture to be treated enters through lead 500A which splits at 505A into two helices 520A and 530A of opposite sense located in the coolant 170L. The resulting condensate and associated gases passes through a tube (550A Figure 4, not shown) into inner collection tank 170B, where the gas separates. When the pressure in the tank reaches a particular value, the head-space gas is led out through choke 170G and the inner of two coaxial helices of liquid 170M, which condenses halocarbons carried over, to exit 170E. When the level of liquid in tank 170B reaches a critical level, a transfer gas is introduced via tube 170F to force condensed liquid in trap back into tank 170B, and then to drive the liquid from this tank into a receiver vessel. The heat-transfer liquid 170L is cooled by introduction of a refrigerant via tube 170D. The process is controlled by computer, using data fed into it by sensors of pressure, temperature and liquid level.