Processing strategies for the production of group II base oils from a conventional lube plant

摘要

Over the last several years the property specifications for lubricating oils have become much more stringent. For passenger car motor oils (PCMO) this has resulted in improved engine efficiency, reduced oil consumption and thereby extended intervals between oil changes, improved cold weather operating characteristics, and reduced environmental impact (1), (2), (3), (4), (5), (6), (7). In general, severe hydroprocessing and/or hydrocracking and isomerization have been proposed as the route to achieve the necessary lube stock property improvements (8), (9). However, there has been ongoing controversy regarding the applicability of these severely hydrotreated stocks for diesel applications (10) and other heavy industrial oils. Also, it is felt that the need for top tier PCMO's for all applications is not completely justified, especially when applied in many of the worlds countries that have very mild weather conditions such as Asia, the Middle East and most of South America (11), (12). These locations have historically met their transportation lubrication needs with monograde oils or other lower specification requirements. There is considerable resistance to the lower viscosity products by the consumer in these regions. Also, PCMO's only constitute about 32