Contribution of Local Reactions in the Grid Zone to the Performance of a Jetting Fluidized Bed Gasifier of Coal Char

Toshinori Kojima, Hiroyuki Yoshitake, Tadashi Kimura, Masahiko Matsukata, Shigeyuki Uemiya

Research output: Contribution to journalArticle

Abstract

The effects of gasification conditions, namely bed temperature, static bed height, and nozzle diameter, on the concentrations of H2, CO, and CO2 were investigated using a batchwise fluidized bed gasifier of coal char. Gas concentration profiles in the bed could be explained by the production of gases chiefly via combustion, steam gasification, CO2 gasification, and the diffusion of produced gases. The temperature dependence of gas concentrations indicates that steam gasification occurred in the lower part of the grid zone at a higher bed temperature and the selectivity of CO production via combustion in the boundary region of the jet and annulus also increased. The results of the effect of static bed height suggest that CO2 gasification mainly proceeded in the bubbling zone and the local reactions in the grid zone were hardly influenced by gas and solid behavior or reactions in the upper part of the bed. Though the diameter and height of the jet would be dependent on nozzle diameter, the effect of nozzle diameter on the local progress of gasification in the grid zone was hardly observed. It can be concluded that gasification proceeded in both the bubbling zone and annulus region, especially near the distributor, while combustion mainly occurred in the jet and boundary of the jet and annulus.

Original languageEnglish
Pages (from-to)379-383
Number of pages5
JournalEnergy and Fuels
Volume9
Issue number2
DOIs
Publication statusPublished - 1995 Mar
Externally publishedYes

ASJC Scopus subject areas

  • Chemical Engineering(all)
  • Fuel Technology
  • Energy Engineering and Power Technology

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