| 摘要 |
PURPOSE: A stable dispersions of finely divided particles of metals and metal compounds that provide metal passivation properties to zeolite containing cracking catalysts and various milling processes for reducing such metals and metal compounds in size and disperse them in water or organic liquids is provided. CONSTITUTION: A catalyst is contacted within a hydrocarbon catalytic cracking unit with a stabilized dispersion. A dispersion comprises a fluid vehicle, a dispersion agent, and finely milled particles of one or more metals or metal compounds for passivation of metal contaminated cracking catalysts. The particles have a volumetric average particle size of less than 0.5 micron, less than 0.25 micron or less than 0.1 micron. As to the size distribution of the particles, approximately 99% of the particles have sizes less than 1 micron or less than 0.3 micron. In order to make the passivating agent dispersions, wet media milling which has an agitator comprising a rotating shaft provided with disks, arms, pins, or other attachments is the preferred process. And the mills is batch or continuous, vertical or horizontal. Another advantage of this method is that the dispersion is easily and precisely metered when added to a hydrocarbon catalytic cracking unit.
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