Prediction of the maximum spoutable height in spout‐fluid beds

Abstract

The development of the semi-theoretical correlation in Hadzisdmajlovic et al. (1983) for predicting the maximum spoutable height in a spout-fluid bed, is observed to involve certain discrepancies. Based on their experimental data, a new correlation is proposed. he concept of spout-fluidization was first introduced by T Chatterjee (1970) and since then several publications have appeared on this subject. Sutanto et al. (1984) observe that the term spout-fluid bed means different things to different authors and that Littman et al. (1976) and Vukovic et al. (1982) refer it to a condition in which normal spouting is accompanied by additional aeration, but not fluidization of the annulus and hence it is more appropriate to call it "Spouting with aeration". The present paper deals with the prediction of the maximum spoutable height in such spoutfluid beds.Littman et al.(1 976) reported that the maximum spoutable height in a spout-fluid bed (HmSf) is the same as that for a spouted bed (H,) for a given system. However, the work of Hadzisdmajlovic (1980) has shown that Hmsf 5 H,, the equality applying only for the case of zero fluid feed into the annulus. The realization that the maximum spoutable height of a spout-fluid bed and a spouted bed are not the same has led Hadzisdmajlovic et al. (1983) to redevelop the equation for predicting minimum spout-fluid flowrate presented earlier by Littman et al. (1976). Since H,, is a parameter in those equations and its knowledge essential for predicting minimum spout-fluid flowrate, Hadzisdmajlovic et al.( 1 983) developed a semi-theoretical correlation for it. Semitheoretical correlation of Hadzisdmajlovic et al., for HmdFor developing the correlation Hadzisdmajlovic et al. (1983) assumed that the radial pressure-gradient at the spout-annulus interface is proportional to the radial velocity u,, and has a maximum value equal to that for minimum fluidization. This assumption gives the following relations On a observk que le dkveloppement de la corrklation semi-thkorique de Hadzisdmajlovic et al. (1983), permettant la prCdiction de la hauteur maximale "spoutable" dans un lit fluidisk "spoutC", impliquait certaines contradictions. On propose une nouvelle corrklation baske sur leurs rksultats expkrimentaux.