Method for generating refrigeration for a carbon monoxide cold box

A method for the separation of carbon monoxide from a syngas feedstock in a carbon monoxide cold box where the cold box is provided refrigeration based on the composition of the incoming syngas feedstock, comprising:

• cooling and partially condensing a cold box syngas feed stream containing carbon monoxide and hydrogen in a primary heat exchanger to produce a cooled and partially condensed syngas feed stream;
• separating the cooled and partially condensed syngas feed stream into a first hydrogen rich vapor stream and a first carbon monoxide rich liquid stream in a first separator;
• feeding the first carbon monoxide rich liquid stream to a second hydrogen removal separator operating at a pressure lower than the first separator, wherein a second hydrogen rich vapor stream is separated from a second crude carbon monoxide rich liquid stream;
• splitting said second crude carbon monoxide rich liquid stream into two portions wherein a first portion of the second crude carbon monoxide rich liquid stream is at least partially vaporized in the primary heat exchanger and providing a second portion of the second crude carbon monoxide rich liquid stream wherein both portions are introduced into a distillation column for separating purified carbon monoxide product stream from a liquid byproduct stream;
• providing a turbine feed stream to a turbine disposed within said cold box;
• and
• providing a cryogenic fluid feed to said cold box from a source external to the carbon monoxide cold box only when the methane content in the incoming cold box syngas feed stream is greater than 3.6 percent.