Polysynaid 8000: Static Control in Gas-Phase HDPE

In gas-phase polyethylene production, electrostatic charging can cause polymer and catalyst fines to adhere to reactor walls. Continued polymerization can form sheets that detach and interfere with fluidization, distributor plates and product discharge. The resulting operating interruptions can increase maintenance requirements and costs, reduce production output and compromise catalyst utilization.

The plant sought to maintain effective static control while evaluating an alternative to its incumbent antistatic treatment, with the broader objective of improving operating economics. The priorities were reliable reactor operation, effective catalyst utilization and smooth product discharge.

• Process: gas-phase fluidized-bed HDPE production using chromium-based catalysts.
• Duration: approximately three and a half weeks, from December 2023 into January 2024.
• Introduction: progressive replacement through the existing single additive tank. The incumbent additive remained present during the transition.
• Additive control: the reported overall antistatic-agent dosage was adjusted within 6–15 ppm in response to reactor static conditions.
• Operating changes: three HDPE grades, two catalyst grades and multiple catalyst-batch changes were included. A temporary upstream feed interruption required an ethylene-source change and a production-rate reduction from 42 to 35 t/h, followed by a return to 42 t/h.

Cestoil’s technical team reviewed plant operating trends before and during the trial, including three reactor static monitoring points, catalyst activity, distributor-plate differential pressure and temperature differences, reactor temperature differences, lump-detector signals, bed density, cooling-system conditions, lump-breaker and vibrating-screen currents, discharge rate and powder particle size.

Static excursions occurred during feed, production-rate and catalyst-batch changes. The report associated these excursions with changing process conditions and noted improved static suppression when antistatic-agent dosing was increased.

Polysynaid 8000 provided effective static control through changing production conditions while maintaining catalyst performance. Catalyst productivity stayed above 7,000 kg/kg, lump detectors showed no frequent alarms or sustained upward trend, and sampled powder retained regular particle shape and good flowability.

These results supported Polysynaid 8000 as a practical alternative to the plant’s existing antistatic treatment. For gas-phase HDPE producers, the trial demonstrates its value in managing reactor static while maintaining catalyst productivity and stable powder handling.