PRESSURIZED DISTILLATION OF METHANOL PLANT

摘要

PURPOSE:To reduce waste heat of low grade and further the total energy consumption of the whole plant, by effectively utilizing the thermal energy held by a reformed gas obtained by steam reforming of a desulfurized hydrocarbon. CONSTITUTION:A desulfurized hydrocarbon is catalytically reformed with steam to give a reformed gas, and crude methanol synthesized therefrom is distilled under pressure. In the process, the following operation is carried out; (i) An initial distillation column 11 is heated to a temperature (70-115 deg.C) 5-25 deg.C higher than the column bottom temperature with a reboiler 16 for recovering the heat of the reformed gas. (ii) A pressurized rectifying column 12 is heated to a temperature (135-225 deg.C) 5-25 deg.C higher than the column bottom temperature with a reboiler 14 for recovering the heat of the reformed gas and a reboiler 17 using steam as a heat source. (iii) An atmospheric-pressure distillation column 13 is heated to a temperature (110-150 deg.C) 5-25 deg.C higher than the column bottom temperature with a reboiler 15 or recovering the heat of the reformed gas, the overhead gas of the pressurized rectifying column 12 by the multiple effect and reboilers 18 and 19 using steam as a heat source.