Application: Hy-Raff is a new process to hydrotreat raffinates from an extraction unit of a solvent-based lube oil plant for upgrading standard Group I lube-base oils to produce Group II base oils. Sulfur is reduced to below 0.03 wt% and saturates are increased to greater than 90 wt%. The integration of this process into an existing base oil plant allows the operator to cost-effectively upgrade base-oil products to the new specifications rather than scrapping the existing plant and building an expensive new hydrocracker-based plant.
The product from the Hy-Raff unit is a lube-base oil of sufficient quality to meet Group II specifications. The color of the finished product is significantly improved over standard-base oils. Middle distillate byproducts are of sufficient quality for blending into diesel.
Description: Raffinate feed is mixed with hydrogen (recycle plus makeup), preheated, and charged to a fixed-bed hydrotreating reactor (1). The reactor effluent is cooled in exchange with the mixed feed-hydrogen stream. Gas-liquid separation of the effluent occurs first in the hot separator (2) then in the cold separator (3). The hydrocarbon liquid stream from each of the two separators is sent to the product stripper (4) to remove the remaining gas and unstabilized distillate from the lube-oil product, and product is dried in a vacuum flash (5). Gas from the cold separator is amine-scrubbed (6) for removal of H2S before compression in the recycle-hydrogen compressor (7).
Licensor: Bechtel Corp.