Application: Bechtel’s MP Refining process is a solvent-extraction process that uses N-methyl-2-pyrrolidone (NMP) as the…
Lube Oil Refining Spent Process by Axens and Viscolube
Application: The Revivoil process can be used to produce high yields of premium quality lube bases from spent motor oils. Requiring neither acid nor clay treatment steps, the process can eliminate environmental and logistical problems of waste handling and disposal associated with conventional re-refining schemes.
Description: Spent oil is distilled in an atmospheric flash distillation column to remove water and gasoline and then sent to the Thermal Deasphalting (TDA) vacuum column for recovery of gas oil overhead and oil bases as side streams. The energy-efficient TDA column features excellent performance with no plugging and no moving parts. Metals and metalloids concentrate in the residue, which is sent to an optional Selectopropane unit for brightstock and asphalt recovery. This scheme is different from those for which the entire vacuum column feed goes through a deasphalting step; Revivoil’s energy savings are significant, and the overall lube oil base recovery is maximized. The results are substantial improvements in selectivity, quality and yields.
The final, but very important step for base oil quality is a specific hydrofinishing process that reduces or removes remaining metals and metalloids, Conradson Carbon, organic acids, and compounds containing chlorine, sulfur and nitrogen. Color, UV and thermal stability are restored and polynuclear aromatics are reduced to values far below the latest health thresholds. Viscosity index remains equal to or better than the original feed. For metal removal (> 96%) and refining-purification duty, the multicomponent catalyst system is the industry’s best.
Product quality: The oil bases are premium products; all lube oil base specifications are met by Revivoil processing from Group 1 through Group 2 of the API basestocks definitions. Besides, a diesel can be obtained, in compliance with the EURO 5 requirements (low sulfur).
Health & safety and environment: The high-pressure process is in line with future European specifications concerning carcinogenic PNA compounds in the final product at a level inferior to 5 wppm (less than 1 wt% PCA – IP346 method).
Economics: The process can be installed stepwise or entirely. A simpler scheme consists of the atmospheric flash, TDA and hydrofinishing unit and enables 70%– 80% recovery of lube oil bases. The Selectopropane unit can be added at a later stage, to bring the oil recovery to the 95% level on dry basis. For two plants of equal capacity, payout times before taxes are two years in both cases.
Licensor: Axens and Viscolube SpA.
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