EQUILIBRIUM MODELING OF A DOWNDRAFT GASIFIER .1. OVERALL GASIFIER

A model, based on the thermodynamic equilibrium of the C-H-O-Inert system and mass and energy balances, has been applied to the air-blown downdraft gasification of wood. The model predicts the temperature, gas composition and char yield at the exit of the gasifier for a specified set of heat loss and input condition. A parametric study has been conducted to simulate the influences of the air/feed mass ratio and moisture/feed mass ratio on the gasifier’s performance. The model predictions are compared with a comprehensive set of experimental data obtained from the gasification of wood in a commercial-scale downdraft gasifier; the air/feed ratios range from 1.1 to 2.1 and the moisture/feed ratios range from 0.05 to 0.3. The predicted trends for variations in the operating parameters are in general agreement with the experimental data. The results of comparisons also indicate that the performance of the wood gasifier can be approximated reasonably well by the equilibrium model. © 1991, Taylor & Francis Group, LLC. All rights reserved.