| Popis: |
When reactive particles which might agglomerate have to be withdrawn quickly from a fluidized bed reactor, intermittent powder discharge reduces the risk of agglomeration by ensuring high turbulence and low residence time in the discharge line. Such a discharge system was studied in a 0.3-m diameter semi-cylindrical fluidized bed of polyethylene powder, at a pressure of 2.5 × 106 N m−2. To avoid momentary defluidization of parts of the bed, which might lead to the formation of agglomerates, the discharge pressure differential should be kept below 1 000 kPa (or 10 atm) and the discharge port should be located near the grid. Although the mass of solids withdrawn with each discharge will be smaller, the frequency of the intermittent discharges could be increased to achieve the required time-averaged discharge flow. |
