Patent ID: 7461521

Claim:
A system comprising: an absorber in which high-pressure methanol is contacted with synthesis gas to transfer impurities including carbon dioxide from the gas to the methanol; a heat exchanger having a top side and a bottom side; a plurality of series-connected expansion vessels including an upstream expansion vessel and a downstream expansion vessel; means for feeding impurity-laden methanol from the absorber through the heat exchanger, through the upstream expansion vessel, and into the downstream expansion vessel for forming in the downstream expansion vessel a body of methanol having a liquid level; a liquid/gas separator; an inlet line feeding methanol from the downstream expansion vessel through the bottom side into the heat exchanger, the inlet line having a portion about 0.5 m below the bottom side; an output line extending from the top side of the heat exchanger to the liquid/gas separator to form therein a body of methanol having a liquid level, whereby carbon dioxide is desorbed from the methanol in the separator, the liquid/gas separator and downstream expansion vessel being relatively oriented such that the liquid level in the downstream expansion vessel is between 1 m and 20 m above the liquid level in the liquid/gas separator, the liquid/gas separator and the heat exchanger being relatively oriented such that the liquid level in the liquid/gas separator is about 0.5 m above the top side of the heat exchanger; and a regenerator receiving methanol from the liquid-gas separator.