The actual low temperature separation takes place essentially in two steps. Initially, CH, and CO are removed by condensing
from the gas mixture after cooling to ca. - 180 .C at 40 bar. The CO and CH, are depressurized to 2.5 bar during the next step in the CO/CH4 separation column. The CO is removed overhead, the CH4 content being less than 0.1% by volume. The process is characterized by a very effective recycling of all gases in order to exploit the refrigeration energy.