The dynamics of interest for grade transitions lie within the reactor and the fast recycle gas loop. The fresh feed is a very small fraction of the recycle gas and is manipulated to control the composition in the reactor headspace. The polymerization reactor is an adiabatic reactor. The heat of polymerization is removed as sensible and latent heat of vaporization by the upward flowing gases through the fluidized bed reactor. The reactor loses a small amount of heat to the ambient.
Hexane is used as an inert in the feed to lower the dew point of mixture.
The cooler is operated at its cooling capacity constraint to maximize the throughput. The polydispersity of both the grades is approximately 2.4. The mass-flow rate of recycle gas is approx. Both the grades have the same reactor duty, temperature and pressure. The product discharge rate is manipulated to maintain the level in the reactor.