The Co unit production capacity is 140 kt/y of Carbon Monoxide,the feed of which is natural gas received from the National Iranian Gas Company at the rate of 87927 T/Y. The feed is mixed with steam after desulphurization and flow through the pre reformer at which higher hydrocarbons are broken to methane,CO,CO2 and Hydrogen and then passes through the reformer where sysngas is formed from the endothermic reaction of methane with steam .The reformer outlet steam is cooled to condensate and separate water ,then its CO2 content is separated by amine solution and returned to the reformer and discharged H2&CO are separated in a cold box to produce pure carbon monoxide product.