Patent ID: 7467527

Claim:
A method for producing carbon monoxide and/or hydrogen and/or a mixture of hydrogen and carbon monoxide by cryogenic distillation, comprising the steps of: a) producing a feed mixture comprising at least carbon monoxide and hydrogen in a production apparatus; b) separating the feed mixture comprising at least carbon monoxide and hydrogen by cryogenic distillation in a separating unit (CB) comprising at least one column; c) collecting carbon monoxide and/or hydrogen and/or a mixture of hydrogen and carbon monoxide from the separating unit; d) in a first operating mode, sending a first quantity of feed mixture to be separated to the separating unit; e) in the first operating mode, producing a quantity of end product that may be carbon monoxide, hydrogen or a mixture thereof; f) in a second operating mode, sending a second quantity of feed mixture to be separated from the production apparatus to the separating unit, a smaller quantity than the quantity sent in the first operating mode; g) in the second operating mode, producing a quantity of end product a smaller quantity than the quantity produced during the first operating mode; h) in the second operating mode, drawing off from the separating unit at least one recycle gas containing carbon monoxide and/or hydrogen and/or methane and having a different composition from the composition of the feed mixture sent to the separating unit in the first operating mode, and sending at least one recycle gas to the separating unit to be separated therein and; i) in the second operating mode, modifying the flow rate and composition of the feed mixture produced by the production apparatus, according to the flow rate and composition of the at least one recycle gas.