Patent ID: 6894080

Claim:
A method of manufacturing methanol comprising: reacting hydrocarbons with water vapor in a reformer to produce a synthesis gas containing hydrogen, carbon monoxide and carbon dioxide; recovering carbon dioxide from combustion exhaust gas which has been discharged from said reformer by a carbon dioxide recovery apparatus provided with a carbon dioxide absorption tower and with a carbon dioxide-absorbing solution regenerating tower; feeding the carbon dioxide thus recovered to the upstream side and/or the downstream side of said reformer; allowing reaction of the synthesis gas to take place over a methanol-synthesizing catalyst to produce a reaction product; recovering liquid crude methanol from the reaction product; distilling the liquid crude methanol in a distillation apparatus provided with a pressure distillation tower and with an atmospheric distillation tower to separate it into refined methanol and waste water containing low boiling point organic compounds and high boiling point organic compounds; wherein bottom liquid in a topping tower of said distillation apparatus is heated and introduced into said pressure distillation tower in the distillation step, and the heat of distilled liquid discharged from the top of said pressure distillation tower is utilized as a heat source for said carbon dioxide-absorbing solution regenerating tower and as a heat source for said atmospheric distillation tower.