A comparison of prediction and experiment in the gasification of anthracite in air and oxygen-enriched steam mixtures

Biomass gasification models for downdraft gasifier: A state-of-the-art review

“…In their study, chars were assumed to consist of pure carbon and those of heterogeneous combustion products were taken as only carbon dioxide. Literature correlations are used for the effective thermal conductivity of the bed [46], the effective bed-to-wall heat transfer coefficients [47], the solid/gas heat transfer and the mass transfer coefficients [48]. However, as a consequence of unsteady heat transfer the solid/gas heat transfer coefficient is multiplied by empirical factors (ξ) with values in the range 0.02-1 [49,50].…”

Modeling wood gasification in a countercurrent fixed‐bed reactor

“…36 for the mass‐transfer coefficient may lead to unrealistic temperature values. Corrective factors, which limit the maximum k (Bhattacharya et al, 1986; Di Blasi, 2000) or reduce k m for all conditions (Goldmann et al, 1985), have also been introduced. The first approach is chosen here with k = 0.15 m/s (Table 1) as a reference value.…”

“…Viscosity and thermal conductivity of the gas are derived from Purnomo et al (1988) The effective thermal conductivities are modeled as in Goldman et al (1984) …”

Predictive Tool To Aid Design and Operations of Pressurized Fixed Bed Coal Gasifiers

“…The air-steam inlet velocities studied ranged from 1.5 to 4.6 cm/s. Goldman et al (1984) reported that, by increasing the air-flow rate in their up-draft gasifier to a high enough value, the reaction zone moved up in the bed ("blow-off"), and it moved back again when the air-flow rate was reduced ("flash-back"). The same effects were qualitatively observed with model simulations, such that as gas velocity increased, the combustion zone moved up in the bed, and the zone moved down with decreased air flows.…”