Effects of draft tube height on solid circulation rate and particle residence time in a RCFB

Abstract

<span style="font-size:11.0pt;line-height:115%; font-family:" calibri","sans-serif";mso-ascii-theme-font:minor-latin;mso-fareast-font-family:="" "times="" new="" roman";mso-fareast-theme-font:minor-fareast;mso-hansi-theme-font:="" minor-latin;mso-bidi-font-family:"times="" roman";mso-ansi-language:en-us;="" mso-fareast-language:en-us;mso-bidi-language:ar-sa"="">Recirculating fluidized bed (RCFB) is a modified form of spouted/spout-fluid bed obtained by inserting a draft tube at the centre to contain the spout. But, with this central riser tube its design and operations are entirely different from that of the conventional spouted/spout-fluid beds. RCFBs are used for a wide range of operations and processes. Solid circulation rate is perhaps the most important factor in predicting the performance of a RCFB. It can be controlled by adjusting a number of design and operational parameters. Experiments have been carried out on a semicircular transparent RCFB to study the effects of draft tube height on solid circulation rate and particle residence time for long draft tubes when the downcomer bed level is below the draft tube top. It has been observed that height of the draft tube affects both solid circulation rate and particle residence time of a RCFB. The data collected may be useful in the selection of appropriate height for the draft tube of a RCFB.</span>