Early Warning of Wall Sheeting in Gas-Solid Fluidized Bed Based on EMD Analysis of Wall Temperature

Wall sheeting or agglomeration is easy to form during production in gas-solid fluidized bed, which seriously affects the safe and stable operation of the reactor. Wall temperature signals are decomposed by Empirical Mode Decomposition (EMD) method, and the first and second intrinsic mode functions, IMF1 and IMF2, are found to increase sharply when sheets are formed. Furthermore, the moving average value of energy of IMF1 or IMF2 (E_m) is effective in indicating initial sheeting. By importing E_m into Principal Component Analysis (PCA), the statistical T² and Upper Control Limit (UCL) are achieved, and the wall sheeting detection method, namely E detecting method, is proposed: when T² < UCL, no sheet is formed;when T² ≥ UCL, sheets are formed. The industrial application results show that, compared with traditional wall temperature fluctuation discriminant or ¹³⁷Cs agglomeration detecting method, E detecting method can achieve early warning of sheeting in advance.