Reverse core-annular flow of Geldart Group B particles in risers

Chew, Jia Wei; Hays, Roy; Findlay, John G.; Knowlton, T.M.; Karri, S.B. Reddy; Cocco, Ray; Hrenya, Christine M.

doi:10.1016/j.powtec.2011.12.019

Cited by 31 publications

(36 citation statements)

References 30 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This evolution suggests that after a given height, particles will be fully accelerated and the flow becomes established. This nonlinear evolution of pressure in the riser is consistent with literature findings [10,22,23].…”

Section: Pressure Profilessupporting

confidence: 93%

“…There is a general lack of reliable modeling and experimental information in the literature on Circulating Fluidized Beds (CFBs) working with large materials. Furthermore, published work on Group B particles does not focus on the impact of particles shape [9,10]. Further studies are required for the reliable scale-up and optimization of the CLC process.…”

Section: Accepted Manuscriptmentioning

confidence: 99%

“…Flux of solids can be measured inside the riser using extraction probes [10,13,14]. The probe tip, with an angle of 90°, is inserted in the riser either facing upwards or downwards to measure downflow or upflow of solids, respectively.…”

Section: Extraction Probesmentioning

confidence: 99%

See 2 more Smart Citations

CFD modeling of riser with Group B particles

et al. 2015

View full text Add to dashboard Cite

International audience– A series of tests were conducted in a large cold flow CFB unit (18 m long riser and 30 cm in diameter) with two different Group B powders. The impact of particle nature on the riser hydrodynamics was investigated at similar operating conditions through pressure taps and extraction probes. To study the impact of particle size and sphericity, sand and glass beads were used. Resulting axial pressure profiles are very different in both the acceleration and in the fully developed region. These differences can most probably be explained by the difference in shape between the solids. Higher sphericity seems to generate smaller pressure drop. Trough extraction probe measurements, the core-annulus regime was found on the developed zone of the riser. An assessment of a commercial CFD code to predict riser flow was carried out. For glass beads, simulation results agree reasonably well with experimental pressure profiles but the core annulus structure is underpredicted. However, pressure drop along the riser is strongly underestimated in sand simulations

show abstract

Section: Pressure Profilessupporting

confidence: 93%

Section: Accepted Manuscriptmentioning

confidence: 99%

See 1 more Smart Citation

CFD modeling of riser with Group B particles

et al. 2015

View full text Add to dashboard Cite

show abstract

“…A membrane autopsy performed by Zappia et al concluded that the unexpected presence of silicon dioxide spicules (needle-like structures) resulted in multiple membrane occlusions and punctures, leading to a loss in membrane integrity [321]. The erosive effect of fluidized particles [322][323][324][325] in the feed stream is also known to compromise the membrane integrity by impacting the membrane surface [123,238,242,[326][327][328][329]. Patterns of particle scraping was clearly observed [238,279], as well as a decrease in the membrane rejection for the larger fluidized glass beads (3 mm) [242].…”

Section: Foreign Bodiesmentioning

confidence: 99%

The Performance and Fouling Control of Submerged Hollow Fiber (HF) Systems: A Review

et al. 2017

View full text Add to dashboard Cite

Abstract:The submerged membrane filtration concept is well-established for low-pressure microfiltration (MF) and ultrafiltration (UF) applications in the water industry, and has become a mainstream technology for surface-water treatment, pretreatment prior to reverse osmosis (RO), and membrane bioreactors (MBRs). Compared to submerged flat sheet (FS) membranes, submerged hollow fiber (HF) membranes are more common due to their advantages of higher packing density, the ability to induce movement by mechanisms such as bubbling, and the feasibility of backwashing. In view of the importance of submerged HF processes, this review aims to provide a comprehensive landscape of the current state-of-the-art systems, to serve as a guide for further improvements in submerged HF membranes and their applications. The topics covered include recent developments in submerged hollow fiber membrane systems, the challenges and developments in fouling-control methods, and treatment protocols for membrane permeability recovery. The highlighted research opportunities include optimizing the various means to manipulate the hydrodynamics for fouling mitigation, developing online monitoring devices, and extending the submerged HF concept beyond filtration.

show abstract

“…For a long time, lots of the experiments related to the CFB have been conducted. Plenty of valuable information have been obtained to understand the gas-solid flow characteristics in the CFB, such as the core-annulus structure (Chew et al, 2012;You et al, 2008;, the cluster characteristics (McMillan et al, 2013;Yang and Leu, 2009), the solid velocity distribution (Pantzali et al, 2013;Yan and Zhu, 2005), the hydrodynamic similarity (Qi et al, 2008), the effect of internal device on solid distribution (Guío-Pérez et al, 2013;Jiang et al, 1991;Samruamphianskun et al, 2012), the particle resident behavior (Harris et al, 2003), and so on.…”

mentioning

confidence: 99%