Abstract
A mechanistic model for noncatalytic solid-gas reactions in fluidized beds is developed. The gas flow and solids circulation are described by accounting for (1) the presence of the cloud-wake phase, (2) decrease in solids by elutriation and chemical reaction, and (3) the solids feed and overflow rates. The solids in the emulsion phase may have a net downward, stationary, or upward movement depending on the rate of solids feed. As a result, other parameters such as bubble volume fraction, bubble rise velocity, and gas velocity in the emulsion phase are also dependent on the solids feed rate. This model considers a general population balance in which both solids size and density vary as a result of reaction. A computer simulation is presented for a representative system which considers a shrinking core solid-gas reaction and an elutriation constant inversely proportional to particle size and density. The results show that the extent of gas bypassing through bubbles is reduced when the solids feed rate is increased. This is particularly significant to a fast-reacting system such as high-pressure coal combustion where the solids feed rate is high.
| Original language | English |
|---|---|
| Pages (from-to) | 149-161 |
| Number of pages | 13 |
| Journal | AIChE Symposium Series |
| Volume | 74 |
| Issue number | 176 |
| State | Published - 1978 |
ASJC Scopus subject areas
- General Chemistry
- General Chemical Engineering