Dry cleaning process and mechanism of gas–solid fluidized bed for waste film plastics

Abstract

Mechanical treatment is the predominant method in waste plastic recycling, and within this context, cleaning of raw material plays a vital role in a preprocessing step. Dry cleaning methods have emerged as alternatives to traditional processes, addressing concerns related to wastewater generation and high energy consumption. However, existing dry cleaning approaches face challenges, particularly regarding efficacy and uniformity. This study employs a pulsed gas–solid fluidized bed apparatus to assess the cleaning efficiency of waste polyethylene film. Cleaning effectiveness and uniformity are quantified using weight analysis and spectroscopy. The investigation examines the impact of cleaning time, superficial gas velocity, agitation, and pulse airflow on the cleaning process. The findings indicate that time emerges as the primary influencing factor, with superficial gas velocity exerting a substantial impact on cleaning effectiveness. In addition, the introduction of pulse airflow significantly enhances both the cleaning effectiveness and uniformity. Under optimal conditions, weight analysis and spectroscopy indicators can exceed 99%, comparable to the conventional water washing methods, and even present potential advantages in spectroscopy indicators. This research contributes valuable insights for improving the efficiency of dry cleaning processes.