Wash system gas separation

Claim 1

In a process for the separation of a gas mixture containing a high volatility component and a low volatility component comprising the steps of (a) cooling said gas mixture; (b) countercurrently contacting said cooled gas mixture with a wash liquid having a volatility below the low volatility component in a substantially adiabatic absorption zone to absorb the low volatility component and pass the high volatility as overhead product and the mixture of wash liquid and low volatility component as a bottoms liquid; (c) reducing the pressure of the bottoms liquid from the absorption zone; (d) fractionating the bottoms liquid recovered from the absorption zone in a fractionation zone to recover an overhead gas comprising the low volatility component and bottoms liquid comprising the wash liquid; (e) recirculating at least part of the bottoms liquid recovered from the fractionation zone as the wash liquid for the absorption zone; the improvement which comprises: (i) passing the cooled gas mixture of step (a) upwardly through a plurality of passages of an isothermal absorption zone for removal of a major portion of the low volatility component prior to passage to said adiabatic absorption zone; (ii) simultaneously passing the bottoms liquid of step (b) downwardly through the same passages of said isothermal absorption zone as is flowing the cooled gas mixture; (iii) maintaining a relative flow velocity between the upward passing cooled mixture and the downwardly passing bottoms liquid so as to avoid liquid entrainment; (iv) passing a refrigerant stream in indirect heat exchange relationship with the upwardly passing cooled mixture and the downwardly passing bottoms liquid whereby the unavoidable heat of absorption accompanying the gas-liquid in the isothermal absorption zone is removed prior to passage of said gas mixture to said adiabatic absorption zone.