stripping steam steam and solvent vapor exiting the top of regenerator column 130 enters acid gas condenser 140 resulting liquids are collected in reflux drum 145 for circulation back to the top of the regenerator column through reflux circulation pump 165 the regenerated hot lean solvent is pumped from the base of regenerator column 130 via rich lean exchanger 125 through lean amine circulation pump 160 and lean amine cooler 150 back into the top of absorber column 110 through lean amine pressure pump 170 where the cycle is repeated filtration of lean solvent at lean amine filter 155 keeps it clear of solids and contaminants including degradation products caused by adverse components of the raw feed gas stream it should be appreciated that filtration could take place in multiple and various locations in the process in one embodiment the composition of this invention includes at least one substituted cyclic diamine component as shown in structure 1 above in a preferred embodiment the composition of this invention includes substituted piperazine moieties with substitution at the 1 and or 4 nitrogen positions of the piperazine ring in other embodiments the composition includes substituted cyclic diamines having a 4 to 12 membered ring exemplary structures of typical mono or bi substituted piperazines of the invention are shown as structure 4 below where r 1 is h alkyl aminoalkyl or structure 5 and r is structure 6 shown below r 2 r 3 r 4 r 5 r 6 r.