Gas Solid Riser Flows Research Articles

Quantitative measurement of solids distribution in gas–solid riser flows using electrical impedance tomography and gamma densitometry tomography

An electrical impedance tomography (EIT) system has been developed to non-invasively measure particle distributions in the riser of a pilot-scale circulating fluidized bed (CFB). Although EIT systems have often been applied to yield qualitative information about gas–solid flows, the present EIT system yields quantitative information that is validated by comparison to a gamma densitometry tomography (GDT) system. EIT and GDT were applied to the CFB riser (14-cm inner diameter, 5.77-m height) containing fluid catalytic cracking particles in air. The flows examined were annular with a dilute core and had average and near-wall solids volume fractions up to 0.25 and 0.66, respectively. For all cases, the average and near-wall solids volume fractions from EIT and GDT agreed to within 0.03 and 0.07, respectively. This good agreement suggests that, where feasible, EIT can be used in place of GDT, which is advantageous since EIT systems are often safer, less expensive, and faster than GDT systems.

The prediction of particle cluster properties in the near wall region of a vertical riser (200157)

Correlations for predicting the properties of clusters of particles travelling near the riser wall are presented. The correlations were developed from experimental data published in the literature on vertical risers ranging from laboratory to industrial scale. Expressions are presented for predicting the size, shape, density, wall film coverage and velocity of particle clusters. These expressions should prove useful in the development of heat transfer and process models for gas–solid riser flow.