Powder conglutination detection in polypropylene production pipelines using acoustic-ultrasonic technique

Abstract In the production of polypropylene, powder conglutination in pipelines easily leads to blockage, which can seriously affect the operation safety of the pipeline, so it is very important to detect and quantitatively evaluate the powder conglutination. This paper proposed an acoustic-ultrasonic (AU) quantitative evaluation method for powder conglutination detection in polypropylene production pipelines. A simulation model was developed to investigate the wave propagation characteristics of conglutinated layers with different areas and thicknesses using stress wave factors (SWF). Experiments were then conducted to develop a quantitative evaluation method for polypropylene powder conglutination. The results show that the relative attenuation coefficients of peak amplitude, peak-to-peak amplitude and the energy and the peak of the power spectrum all follow an approximate linear relation with the areas and thicknesses of the conglutinated layers. For either area or thickness evaluation, the energy or the peak of the power spectrum of AU signals has higher sensitivity than peak amplitude or peak-to-peak amplitude. Moreover, compared with conglutinated area evaluation, all the SWF models for thickness evaluation were more reliable, where the errors were all less than 7%. As a result, the AU technique is an effective means to detect powder conglutination in polypropylene production pipelines, and high sensitive and accurate quantitative evaluation is feasible with some of the stress wave factors of AU signals.