| abstract |
The present invention is a method of reducing the formation of fouling deposits occurring in a caustic scrubber used to remove acid gases comprising : a) providing a caustic scrubber fed with an alkaline aqueous solution comprising essentially one or more of NaOH, KOH or LiOH, b) providing an olefin-containing hydrocarbon stream, contaminated with oxygenated compounds and acid gases, and said oxygenated compounds are capable to make polymeric fouling deposits in the presence of the alkaline solution of the scrubber, c) sending the above hydrocarbon stream to the caustic scrubber to recover an olefin- containing hydrocarbon stream essentially free of acid gases, wherein, d) an efficient amount of a solvent capable to reduce the formation of fouling deposits is introduced in the caustic scrubber and/or in the alkaline solution fed to the scrubber, e) the liquid outlet of the scrubber is sent to means to separate the solvent from the alkaline solution, f) optionally an additive capable to reduce the conversion of the oxygenated compounds to polymeric fouling deposits in the presence of the alkaline solution of the scrubber is introduced in the caustic scrubber and/or in the alkaline solution fed to the scrubber. In an embodiment the solvent separated from the alkaline solution at step e) is treated to eliminate heavies and recycled at step d). Said treatment can be a stripping or a distillation. In an embodiment the means of step e) to separate the solvent from the alkaline solution are located in the bottom of the scrubber. In an embodiment the caustic scrubber has several stages with various caustic concentrations. The solvent injection and removal can be located at each stage. |