GB1501195A - Method of removing co2 and/or h2s from a gaseous mixture containing same - Google Patents

Abstract

1501195 Removal of CO 2 and/or H 2 S from gaseous mixture G GIAMMARCO and P GIAMMARCO 22 May 1975 [28 May 1974] 22382/75 Heading C1A An acidic gas comprising CO 2 and/or H 2 S is removed from a gaseous mixture in an absorption stage, by contacting with an aqueous solution of an alkali metal carbonate and added amino acid, and a regeneration stage where the acidic gas is expelled from the absorbing solution, where the absorption stage is operated in two subsequent zones, at 90-130‹ C. to remove a major proportion by volume of CO 2 and/or HIS and 50-85‹ C. to remove the remaining minor proportion by volume of CO 2 and/or HIS respectively. The amino acid concentration in the first zone, preferably 30-50 gl.<SP>-1</SP>, may be lower or equal to that in the second zone, and the preferred amino acid is glycine. The regeneration stage may comprise two zones. Compounds of arsenic and/or vanadium may be added to the absorbing solution as corrosion inhibitors. In a first embodiment, shown in the drawing, an absorbing solution (typically containing 150-250 gl.<SP>-1</SP> of the CO 3 expressed as K 2 O and 100-150 gl.<SP>-1</SP> glycine) at 110-115‹ C. is pumped from the bottom of regeneration column R by a pump P 2 and conveyed through heat exchanger Sc and cooler F to the top of the absorption column A. The solution descends in the upper zone A 2 in countercurrent with the gaseous mixture already partially purified in the lower zone A 1 , and the exhausted solution collecting at partition C is discharged through pipe T and preheated in heat exchanger Sc, before being delivered to the top of the lower regeneration zone R 2 where it is heated and regenerated by steam evolving from the bottom of R. A second solution (typically containing 200-250 gl.<SP>-1</SP> K 2 CO 3 and 50 gl.<SP>-1</SP> glycine) is pumped by P 1 from partition D of R at 108-110‹ C. to the top of A 1 . The exhausted solution collects at the bottom of A and is conveyed to zone R 1 for regeneration. To carry out a second embodiment, where a single absorbing solution at low concentration of amino acid (typically 30-50 gl.<SP>-1</SP> glycine) is used in both absorption zones, the pipe T and the heat exchanger Sc are eliminated from the drawing. A third embodiment uses a single regeneration zone, and the regenerated solution is split into a minor and a major fraction by volume. The minor fraction is cooled to 50-85‹ C. and is supplied to the top of A, and the remainder is passed to an intermediate section of A.