Improvement of Fluidization Quality Using Promoter and Modified Design of Distributor–A Review

Persistent efforts were made by various researchers to improve the quality of gas-solid fluidized bed by means of hindering the bubble formation, avoiding the coalescence of bubbles through bubble breakage, thereby exhibiting a meticulous bed expansion and fluctuation. To conquer these difficulties and to achieve a better fluidization quality use of distributor, turbulence and promoter has been recommended and emerged as an alternative and effective technique.  The introduction of promoters performs well in smoothening the fluidization operation in terms of infringement of bubbles, and regulating the bubble size through inhibiting their growth. A better fluidization quality is achieved by various fluidization characteristics such as bed expansion, fluctuation, mixing index and minimum fluidization velocity. Therefore, various researchers investigated the usage of different types of promoters and distributors and recommended that by using a suitably designed promoter and distributor possess an improved fluidization quality with marginal fabrication cost, however the operational cost remains unchanged. Most of the literature studies are dealt with the qualitative effect of the usage of promoters and distributors in a gas-solid fluidized  bed though investigation of various hydrodynamics characteristics viz. bed expansion ratio, bed fluctuation ratio, bed pressure drop ratio.