Propylene, ethylene and any other required comonomers
are fed into the reactor(s). Hydrogen is added to control the molecular weight. Polymerization conditions (temperature, pressure and reactant concentrations) are set by the polymer grade to be produced. The reaction itself is exothermic. Reactor cooling is achieved by evaporation of liquefied reactor gas, which is injected into the reactor. Flash evaporation of the liquid in the polymer bed ensures the most efficient heat removal.

The polymer powder is discharged from the reactor(s) and separated from the gas in the discharge vessel at atmospheric pressure. Any unreacted monomer separated from the powder is compressed and either recycled or returned to the upstream olefins unit for recovery. The polymer is flushed with nitrogen into the purge vessel to remove residual propylene. The purge vessel offgas is sent to a recovery system. The powder is conveyed to powder silos and then converted into pellets that incorporate a full range of well-dispersed additives.

For highly demanding applications requiring extremely low volatiles and odor levels, the Novolen process offers an optional desorber unit to treat the pellets after extrusion.