Hydrocarbon gas processing

1532335 Separating gases ORTLOFF CORP 20 April 1977 [9 Aug 1976 4 Oct 1976] 16399/77 Heading F4P A partly liquefied stream 33a of compressed gas comprising mainly methane and ethane is separated at 16 into liquid and gas portions the liquid fraction 34 being mixed with a process stream of lower bubble point (a portion 169 of the gas fraction as shown) and cooled before expansion at 155 into a fractionation column 19, As shown, the combined stream is cooled at 154 by overhead residue gas 158, and the balance 170 of the gas fraction is work expanded at 17 and fed to the column 19. The liquid fraction may be further cooled before being mixed with the gas fraction by heat exchange with an expanded portion of the liquid fraction, Fig. 5 (not shown). The process is stated to produce higher yields of ethane (and propane) than the prior art without an increase in energy requirements.