Petroleum, metal contaminant levels

RCC [Reduced crude oil conversion] A process for converting reduced crude oil (a petroleum fraction), and other petroleum residues, into high-octane gasoline and other lighter fuels. Based on the FCC process, but adapted to accommodate higher levels of metal contaminants which can harm the catalyst. Developed by Ashland Oil Company and UOP and... 

In the analysis of metals in petroleum and petroleum products one of the most common sample preparation procedures is the dilution of the sample with an organic solvent such as xylene, methyl isobutyl ketone (MIBK) or white spirit. It is of great importance that the solvent system chosen is as free as possible from metallic contamination. Elements such as sodium and zinc are commonly found in many organic solvents. Similarly, other reagents such as mineral acids must be investigated for metal content before use. Where ultra-trace level determinations are to be attempted the reagents used may need to be purified. For solvents, the use of redistillation or extraction with mineral acid may improve the blank levels. 

ROPE has been demonstrated for its tar sand applications in field-level studies. Western Research Institute claimed that ROPE technology could be applied to oil-contaminated dirt, tires, petroleum bottoms, oil shale, and tar sand and noted that the process could potentially remove volatile metals such as mercury from soils. Hydrocarbon Technologies, Inc., intends to develop the technology only for tire recycling. The ROPE process has not been tested at a commercial level. 

The characterization of petroleum cracking catalysts, with which a third of the world s crude oil is processed, presents a formidable analytical challenge. The catalyst particles are in the form of microspheres of 60-70 micron average diameter which are themselves composites of up to five different micron and submicron sized phases. In refinery operation the catalysts are poisoned by trace concentrations of nickel, vanadium and other contaminant metals. Due to the replacement of a small portion of equilibrium catalyst each day (generally around 1% of the total reactor inventory) the catalyst particles in a reactor exist as a mixture of differing particle ages, poisoning levels and activities. 

The significant effect of traces of iron, nickel, copper and vanadium in petroleum feedstocks on processing economics has been responsible for the continuing attention focused on improvements in trace metal analytical procedures. This interest has intensified in our company because of the wide variety of crude oils now processed coupled with the need to meet more stringent contamination factors. These needs have increased demands on our laboratories for routine analyses at levels of less than 1 ppm. As a consequence our group was asked to evaluate requirements for trace metal analysis and to determine to what extent methods presently described in the literature could be adapted to our needs. 

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