An improved electroresistivity probe has been used in a freely bubbling gas-fluidised bed of carbon particles to give the distributions of velocitj and size of bubbles therein. Bubble properties agree with previous observations but the significant influence of macro-circulation patterns on bubble ve
Bubble velocities and bed expansions in freely bubbling fluidised beds
β Scribed by K. Godard; J.F. Richardson
- Publisher
- Elsevier Science
- Year
- 1969
- Tongue
- English
- Weight
- 661 KB
- Volume
- 24
- Category
- Article
- ISSN
- 0009-2509
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β¦ Synopsis
Measurements of bubble velocltles m freely bubbhng beds have shown that the veloclhes of mdlvldual bubbles are mfluenced more markedly by the dlsposltlon of surroundmg bubbles than by the slze of the mdlvldual bubble ltself Bubbles present m high concentratlons nse at much greater velocItIes than Isolated bubbles of the same volume The apparent anomahes reported by Pyle and Hamson for the expanslon of bubbhng beds have been explamed m terms of bubble velocItIes m excess of slug velocltles
π SIMILAR VOLUMES
The rising velocity of an isolated bubble in a "two-dimensional" air-fluidised bed has been measured and found to be wel1 described by the relation, ub= 15'9Abf cm/sec, where Ab is the area of the bubble measured in cm\*. This predicts a smaller rising velocity than the corresponding @avies and Tayl
Knowledge of bed expansions is important in the design and operation of gas-solid fluidized beds. This paper presents a study on the estimation of expanded bed height in a large three-dimensional gas-fluidized bed with a square section of 0)61;0)61 m. All experiments were performed at the freely bub
An illustration of Nicklin's conclusions for two-phase flow is given, and application of these conclusions is made to the two-phase theory of fluidised beds. Some expressions previously derived for fluidised beds are believed now to require reconsideration.
## Abstract Low density polyethylene and polypropylene are produced at large scale via the Unipol process. In this process catalyst particles are fluidised with monomer gas and grow into polymeric particles up to a size of 1βmm. The process is operated at 20β25 bar. Pressure plays an important role