A novel non-intrusive probe of particle motion and gas generation in the feed injection zone fo the feed riser of a fluidized bed catalytic cracking unit

摘要

We define a non-intrusive Acoustic Shot, Noise, ASN, probe of particle velocity at the wall of fluidized beds and transfer liines, and demonstrate how it can be used to obtain quantitative data on changes in particle velocity at the wall through cnages in the mean squared wiall acceleration of the wall vibrational energy produced by random particle impact or ASN. We note that the probe can be simply calibrated if any two of the following quantities are known for the transfer line: (1) average Axial Velocity of particles; (2) average Axial Mass Density of particles; (3) average Mass FLux of particles. We present the first field data on simultaneous measurements of ASN excited wall vibrational energy along the feed riser of Fluidized Catalytic Cracking Units where catalyst particle flow is produced by the gas generated in the catalytic and thermal cracking of injected oil. We define the Feed Riser Profile as the curve of RMS acceleration along the feed reiser and show that changes in its magnitude and shape can be correlated with changes in the product yield of the catalytic and thermal cracking process.