method of maintaining a melt flow index of a polyethylene polymer product

摘要

the present disclosure provides a method of maintaining a melt flow index target value of a polyethylene polymer product, which is synthesized with a metallocene catalyst, in a gas-phase fluidized bed reactor. the method includes producing the polyethylene polymer product at the target value of the melt flow index, with a metallocene catalyst, in a gas phase fluid bed reactor in a steady state, in which the gas phase fluid bed reactor is at a first reactor temperature and receives hydrogen and ethylene feed at a hydrogen to ethylene feed rate at a first ratio value. when a change in reactor temperature is detected, the hydrogen to ethylene feed rate is switched from the first ratio value to a second ratio value in order to maintain the melt flow index value of the polyethylene polymer product at the target value.