Abstract:
Pure ethylene is fed to a fluidised bed of polymer particles maintained at
85-l050C and 20 bar according to the polymer grade. Catalyst (chromium on
silica) is injected continuously. Conversions of 2-3 percent with an
average residence time of 3-5 hours.
Separation is carried out by successive pressure letdowns. The HOPE in the
form of a powder is separated and blended with small amounts of stabiliser
for storage.