Raffinate hydroconversion

Raffinate HydroConversion (RHC) corresponds to a severe hydroprocessing, which is applied only to selected stocks, as opposed to the treatment of the entire slate. The purpose of the hydroconversion, which is carried on a proprietary sulfided catalyst, is to increase the VI while preserving the yield of lubes and wax. RHC is very effective at removing heteroatoms such as sulfur and nitrogen and at hydrogenating aromatics. 

Raffinate hydroconversion (RHC), which can be viewed as a drop-in process upgrade for an existing solvent extraction plant. 

The raffinate hydroconversion process, developed by Exxon Research and Engineering,30 was developed to upgrade the solvent refining process at Exxon s... 

Source J. E. Gallagher, Jr., I. A. Cody, and A. A. Claxton, Raffinate Hydroconversion. Development and Commercialization of Raffinate Hydroconversion—A New Technology to Manufacture High Performance Basestocks for Crankcase and Other Applications, Paper LW-99-121, presented at the National Petroleum Refiners Association meeting,, 1999. With permission. 

Gallagher, J.E. Cody, LA. Claxton, A.A., Raffinate Hydroconversion, Lubr. World,... 

An important aspect of this process is the use of raffinate feeds that are under-extracted relative to the raffinates required to meet typical Group I basestock properties using extraction only. In the combined process this lower severity mode takes best advantage of the extraction step because a higher percentage of the species removed into the extract phase are clustered aromatic ring stmctures with few aliphatic characteristics. In other words, the species that have the least potential to be converted into more highly paraffinic stmctures in the subsequent hydroconversion step are removed more selectively when the extraction treat is mild. 

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