Process for separating coal synthesized methane from unreacted intermediate and contaminant gases

A process for separating components of a synthesized gas containing methane, hydrogen, carbon monoxide and carbon dioxide, comprising the steps of:

• contacting said synthesized gas with a liquid carbon dioxide scrub stream in an absorption column to form (1) a solute-carrying liquid carbon dioxide stream having dissolved therein a major portion of the methane in said synthesized gas, and (2) a gas stream comprising major portions of the hydrogen and carbon monoxide in said synthesized gas;
• fractionating said solute-carrying stream in a first fractionating column to form (1) a first fractionator bottoms comprising liquid carbon dioxide having dissolved therein the major portion of the methane in said solute-carrying stream, and (2) a recycle gas comprising methane, carbon dioxide, and major portions of the residual hydrogen and carbon monoxide in said solute-carrying stream;
• recycling said recycle gas into contact with said scrub stream in said absorption column;
• fractionating said first fractionator bottoms in a second fractionation column to form (1) a second fractionator overhead gas stream rich in methane and (2) a second fractionator bottoms comprising liquid carbon dioxide substantially free of methane;
• and
• recycling said liquid carbon dioxide of said second fractionator bottoms to said scrub stream introduced into said absorption column.