Application Of Acoustic Emission Technology In Process Parameters Measurement Of The Fluidized Bed Reactor

On-line detection of key parameters in fluidized bed reactor is essential to process control optimization and safety production. The acoustic emission (AE) technology has been successfully applied to the measurement of key parameters as agglomeration and bed level in industrial fluidized bed since it is safe, environmental, real-time and non-intrusive. However, the practical application of this technology indicates further improvement is needed due to a small detection precision of bed level and a limited detection range of agglomeration. In order to study the anti-interference performance and detection range of AE detection systems with different AE sensors, experiments were carried out to investigate the influence of mechanical knock, particles layout, sensor types and measuring positions on system performance. Results indicated that AE sensor which had a narrow resonant frequency band was suggested to be used in hostile industrial condition. The detection precision could be improved by extracting information and modeling through cross-spectrum analysis and high-order spectral analysis of AE signals. Industrial experiment results indicated the measurement position where double coherence coefficient of AE signal reaches the maximum and variance reaches minimum can be determined as the bed level. The average relative deviation between bed level measured by AE technology and pressure drop was 5.4%. In addition, AE sensors can also be mounted on the distributor, catalyst feed supporting tube and discharge tube, on which a larger detection range of agglomerates was found. The sensors on catalyst feed tube and discharge tube have a large AE energy and are more sensitive compared to these on distributor. This work improved the detection precision of bed level and enlarged the detection range of agglomerates, which is essential to the industrial reactor optimization and process intensification.