I wanted to understand the constituents that cause the coloring in say natural gasoline. I'm working on an NGL fractionation unit & the Debutanizer bottoms is routed to a Decolorizer column. Now, I'm not sure what is removed to actually meet the D-156 saybolt color 20 specification. its gas condensate...C5-C20, mercaptans inc heavy mercaptans i.e c5,c6 mercaptab, BTEX. No MEROX unit on the feed stream..so no DSO. Also no N2/ nitrogenous compounds.
I would be very grateful if somebody could share the HC compounds contributing to color other than the obvious DSO/ N2 compounds.