Patent ID: 8084554
Filing Date: 2011-12-27
Classification: C08F,Y02P

Abstract:
1. A method for the polymerization of an alpha-olefins in a fluidized bed reactor in the presence of a catalyst that may cause sheeting during the polymerization, by maintaining a static electric charge in the reactor at the site of possible sheet formation below static voltage levels which would otherwise cause sheet formation by introducing a chromium-containing compound into the fluidized bed reactor in such manner as to contact the surfaces of the reactor, the chromium in the chromium-containing compound being present in a valence state from 2 to 3, the method comprising: oxidizing the chromium, and forming a high molecular weight polymer coating greater than 0.25 mm thick on a bed section wall of the fluidized bed reactor, wherein the oxidizing step is completed in less than 2 hours, and wherein the high molecular weight polymer coating is formed by reacting the oxidized chromium with ethylene.