| 摘要 |
PURPOSE:To cheaply produce liquefied carbon dioxide by allowing CO2 gas to be absorbed in a low temp. hydrophilic org. solvent under a press. below the triple point while solidifying part of the gas if necessary and by fractionally distilling this liquid in a press. fractionating tower of above the triple point. CONSTITUTION:Feed CO2 gas is introduced into packed tower 2 provided with LNG cooler 1, and the gas is countercurrently contacted to a cooled hydrophilic org. solvent such as methanol. The CO2-absorbed methanol is pressurized to above the triple point, e.g. 6 kg/cm<2>G with pump 3, preheated with heat exchanger 4, and fed to the medium stage of press. fractionating tower 5. CO2 gas leaving tower 5 is cooled with LNG or the like in condenser 7 and liquefied. Impure gas in the feed CO2 gas dissolved in the methanol is separated in reflux cooler 8 and exhausted from the system. The bottom residue in tower 5 is returned to absorption tower 2 through exchanger 4 and cooler 13, yet part of it is passed through rectifying tower 11 to remove water, and methanol is fed to cooler 13. |
