Process and apparatus for cooling a compressed gas stream which utilizes one or more elongated vessels having a substantially vertical orientation. Each vessel has one compartment for indirect heat exchange between the compressed gas stream and a cooling stream and a second compartment for direct contact between the compressed gas stream and a liquid stream. The two compartments are separated by a barrier, which allows for upward passage of air, but prevents the downward passage of liquid. The design permits one to use the heat present in the compressed air efficiently.