METHODS FOR REMOVING HEAVY HYDROCARBONS FROM EXTRACTIVE SOLVENTS

摘要

A method for cross connecting the lean solvent supply lines between the liquid- liquid extraction. (LLE) and the extractive distillation (ED) processes thereby using the LLE column as the outlet for removing accumulated heavy hydrocarbons (HCs) and polymeric materials from the solvent loop of both processes to maintain their solvent•performance. The unique capabilities of the LLE column in rejecting heavy HCs from the solvent into a raffinate product stream that leaves the system enable the removal of the accumulated heavy i:!Cs and polymeric materials from the closed solvent loop of the ED process when their lean solvent loop are cross connected. Cross connection requires minimum equipment change. In the revamped system, the solvent recovery column (SRC) in LLE process supplies lean solvent for the extractive distillation column while the SRC of the ED process supplies lean solvent for LLE column.