Cryogenic separation, commonly referred to as a cold box, is used for the separation of CO from a syngas stream. The syngas is typically pretreated to remove any impurities that would freeze at cryogenic temperatures, primarily water and carbon dioxide. The components of the syngas are then separated using differences in their boiling points. There are typically three variations of CO cold box designs: methane wash, partial condensation and CO wash. The design can be tailored to meet the required CO specifications. Most of the required non-rotting equipment is compactly integrated into a box that is filled with insulation.