Apparatus and method of producing dimethyl carbonate by reactive distillation using hybrid heat integration

A distillation apparatus for preparing dimethyl carbonate comprising:

• a reactive distillation column;
• a reactive distillation column reboiler;
• a reactive distillation column condenser;
• and pressure-swing distillation columns,
• wherein:
• the reactive distillation column comprises reaction stages in which a reaction that produces ethylene glycol and an azeotropic mixture containing methanol and dimethyl carbonate from transesterification of ethylene carbonate occurs;
• the reactive distillation column reboiler connected to the reactive distillation column discharges the ethylene glycol as a liquid;
• the reactive distillation column condenser connected to the reactive distillation column liquefies the azeotropic mixture, and
• the pressure-swing distillation columns include a high-pressure distillation column and a low-pressure distillation column,
• wherein the high-pressure distillation column separates dimethyl carbonate in a liquid state from the azeotropic mixture liquefied in the reactive distillation column condenser,
• the low-pressure distillation column separates methanol in a liquid state from the azeotropic mixture liquefied in a high-pressure distillation column condenser connected to a top of the high-pressure distillation column, and
• the pressure-swing distillation columns have a double annular distillation column structure for internal heat integration.