Application: To produce high-density polyethylene (HDPE) and medium-density polyethylene (MDPE) under low-pressure slurry process “CX process.”
The CX process uses two polymerization reactors in series. The products have bimodal molecular-weight distribution (MWD), where MWD and composition distribution is freely and easily controlled by adjusting the operating conditions of two reactors without changing the catalyst.
This process produces a wide melt index range by applying innovative catalyst chemistry combined with a sophisticated polymerization process. An all-round catalyst and simple polymerization operation provide easy product changeover that reduces transition time and yields negligible off-spec product from the transition. Mitsui has also developed new catalyst that contributes better morphology of the polymer powder and ethylene consumption.
Ethylene, hydrogen, comonomer and super-high activity catalyst are fed into the reactors (1). Polymerization reaction occurs under a slurry state. The automatic polymer property control system plays a very effective role in product quality control. Slurry from the reactors is fed to the separation system (2). The wet cake is dried into powder in the dryer system (3). The solvent is separated from the slurry and as much as 90% of separated solvent is directly recycled to the reactors without any treatment. The dry powder is pelletized in the pelletizing system (4) along with required stabilizers.
Licensor: Mitsui Chemicals, Inc.