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U.S. Department of Energy
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Hydrotreat used lube oil

Journal Article · · Hydrocarbon Process.; (United States)
OSTI ID:5374101

Mild hydrotreating is the key to successful re-refining of used lubricating oils. Coupled with pre-distillation and metals removal, the process produces oil of superior color and clarity with acceptable viscosity and heteroatom content. Furthermore, the entire process provides operational simplicity, economic feasibility and environmental attractiveness. Re-refining preserves a valuable resource while solving a potential environmental problem. Increased sensitivity to disposal of hazardous material once again makes re-refining almost a necessity. Various technologies developed to re-refine used lubricating oils range from simple acid/clay contacting to complex solvent extraction. Most technologies require similar capital investment; however, operating costs vary substantially. Current technology seems to converge on a two-step procedure: distillation of dehydrated used oil in a thin-film evaporator, and subsequent hydrotreating of distilled stocks. Filtered used oil is first dehydrated in a flash tower, which also removes some light hydrocarbons. It is then distilled in a thin-film evaporator, which allows feed fractionation with minimal thermal degradation. Hydrotreating of distilled lubes is conducted in two trickle-bed reactors in series. The first reactor contains a guard-bed material (e.g., high-surface-area alumina) and the second contains hydrotreating catalyst. Hydrotreating improves product color and reduces the level of halogen-, sulfur-, oxygen-, and nitrogen-containing compounds. While distillation is a common, well-understood technology, application of hydrotreating to recycled lube oil raises many questions.

Research Organization:
National Institute for Petroleum and Energy Research, Bartlesville, OK
OSTI ID:
5374101
Journal Information:
Hydrocarbon Process.; (United States), Journal Name: Hydrocarbon Process.; (United States) Vol. 65:4; ISSN HYPRA
Country of Publication:
United States
Language:
English