Contaminants in the used oil II

 For sulfur determination, total sulfur measured in the unused lube oil or used lube oil is about 0.3wt% or even to 0.4wt%. Sulfur is added to base lube oil (contains total sulfur at only 0.05wt% for 100 neutral base oil and 0.07wt% for 300 neutral base oil) from the additive packages and should be removed during the recycling operations. In most cases, sulfur compounds produce acidic gases to cause corrosion problems in the treatment facilities. Thus, it is better to remove sulfur compounds early from the process flow. Unfortunately, they are always not removed until the last step (Refer to Table 2-4, in re-refining system), or only release as acidic gases (in reprocessing system) to create problems. Total sulfur content in treated samples is not determined due to incomplete water separation. The samples valid for total sulfur measurement by Horiba SLFA-20 are limited for whose water content is under 1%. The procedure for identifying different sulfur compounds in any oil phase by GC-MS is still under development in BNL and will be ready to routinely conduct the determination of different types of sulfur compounds after the database is completely set up