Mathematical modeling of coal-fired fluidized bed combustors

✍ Scribed by J.L.T. Azevedo; M.G. Carvalho; D.F.G. Durão

• Publisher: Elsevier Science
• Year: 1989
• Tongue: English
• Weight: 636 KB
• Volume: 77
• Category: Article
• ISSN: 0010-2180
• DOI: 10.1016/0010-2180(89)90107-7

✦ Synopsis

Their performance is tested against experimental data for different operating conditions. The importance of the different assumptions is analyzed and discussed. For the conditions analyzed in the present article the model of Rajah and Wen more closely follows the experimental trends. However, some deficiencies were detected and an improved version of this model is presented. Special attention is devoted to the computation of the carbon loading and bed expansion ratio.

NOMENCLATURE

At cross section area of the bed (m 2) Ao area of the cross section by each nozzle opening (m 2) Db bubble diameter (m) Dg gas diffusivity (m 2 s-1) Dt bed diameter (m) g acceleration due to gravity (m s-2) h height above the distributor (m) K~ mass transfer coefficient (s-l) Ub absolute bubble velocity (m s-l) Ue velocity of air through the emulsion phase (m s-1) Umf minimum fluidization velocity (m s-l) Uo superficial velocity (m s-1) Vo volumetric flow rate from a single nozzle opening (m 3 s-1) Greek ~b bubble fraction in the bed ~' c fraction of cloud-wake and bubble in the bed ee void fraction in the emulsion phase