SELECTIVELY REMOVING UNDESIRABLY SIZED CATALYST PARTICLES FROM A REACTION SYSTEM

摘要

The present invention provides various processes for selectively removing undesirablysized catalyst particles from a reaction system. In one embodiment, a pluralityof catalyst particles, having a first median particle diameter, is withdrawnfrom the reaction system and is directed to a separation unit such as a counterflow cyclone separator. In the separation unit, the particles are separatedinto a small catalyst stream and a large catalyst stream, the small catalyst streamhaving a second median particle diameter less than the first median particlediameter, and the large catalyst stream having a third median particle diametergreater than the first median particle diameter. At least a portion of the smallor large catalyst stream is then directed back to the reaction system in orderto maintain a desirable particle size distribution therein.