The kinetics of combustion of petroleum coke particles in a fluidized-bed combustor

A multiscale mass transfer model for gas–solid riser flows: Part 1 — Sub-grid model and simple tests

“…The upper and the lower limits of the variation are calculated from the expression of k eff,lower and k eff,upper , of which G s is given in range of 0.01.200 kg/m 2 s for a given U g . It is interesting to note that many of the correlations reported for gas-solid mass transfer in risers (Gunn, 1978;Halder and Basu, 1988;Kettenring and Manderfield, 1950;Resnick and White, 1949;Subbarao and Gambhir, 2002;Venderbosch et al, 1999;Wang, 2002;Van der Ham et al, 1991;Dry et al, 1987;Dry and White, 1992), though differing much from each other even in the order of magnitude, fall into the striped area bounded by the Wakao and Kaguei (1982) Sh = 2.0 + 1.1Re 0.6 Sc 1/3 3 < Re < 3000 La Nauze and Jung (1982) Sh = 2.0 g + 0.69 1/2 g Re 1/2 Sc 1/3 d p,a = 3 × 10 −3 .1.5 × 10 −2 m (active particle); d p,i = 6.55×10 −4 .9.25×10 −4 m (inert particle); 6 < Re a < 8 dash envelope lines of the two limits. For more detailed comparison, Figs.…”

“…(7) denotes the contribution from molecular diffusion and the second term denotes the contribution from convection. The values of the parameters (c 1 , c 2 , c 3 , c 4 ) are widely reported in the literature (Halder and Basu, 1988;La Nauze and Jung, 1982;Nishimurat and Ishii, 1980;, and most of them are derived from the formula by Ranz and Marshall (1952a,b). Here, we take the form for single particles with (c 1 = 2.0, c 2 = 0.6, c 3 = 0.5, c 4 = 0.333).…”

Mass Transfer around Active Particles in Fluidized Beds

“…The arbitrary choice of the average bed quantities ε and Re, instead of the dense phase ones ε mf and Re mf , was not justified by the authors nor validated by their experimental data. The first work in which the mass transfer coefficient was determined from combustion rate data was that reported by La Nauze & Jung (1982, 1983a and Jung & La Nauze (1983). These authors performed experiments where single petroleum coke particles were burned in a fluidized bed and the mass loss of carbon was measured as a function of time.…”

Evaluation of the Limiting Regime in Iron Ore Fines Reduction with H2‐Rich Gases in Fluidized Beds: Fe2O3 to Fe3O4

“…Further, the mass transfer is dependent on fluid-dynamic and diffusive parameters. According to LaNauze and Jung [5], the Sherwood number, which describes the mass transfer through the laminar layer, is defined as: Further, the mass transfer coefficient is given as [6]:…”

“…in which, according to LaNauze and Jung [5], the effective diffusion coefficient is described as in Eq. (8)…”