Riser hydrodynamic study with different Group B powders

Rodrigues, S. Sofia M.; Forret, Ann; Montjovet, Florian; Lance, Michel; Gauthier, Thierry

doi:10.1016/j.powtec.2014.12.014

Cited by 9 publications

(8 citation statements)

References 24 publications

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“…As already described in [12], for identical operating conditions, sand pressure profiles are about twice as high as glass beads pressure profiles. This is a very large, significant and unexpected difference.…”

Section: Pressure Profilessupporting

confidence: 61%

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CFD modeling of riser with Group B particles

et al. 2015

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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

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Section: Pressure Profilessupporting

confidence: 61%

“…Experimental data, using three different Group B solids can be found on [11]. The development of a 1D model of the riser and the development of a new drag force correlation for Group B solids has been achieved [12].…”

Section: Accepted Manuscriptmentioning

confidence: 99%

CFD modeling of riser with Group B particles

et al. 2015

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“…The drag force strongly affects the solid transport and the internal circulation of the solid phase in the system. In the literature, there exist empirical correlations for the one-dimensional (1D) analysis of the slip factor and drag force 50 and also the utilization of the slip velocity for determining the solid residence time. 51 Figure 10 presents the radial (a) and axial (b) distributions of the drag force and slip velocity of the solid phase, which are calculated as the sectional-averaged particle-scale information of the solid phase.…”

Section: Resultsmentioning

confidence: 99%

Shape Effect of the Riser Cross Section on the Full-Loop Hydrodynamics of a Three-Dimensional Circulating Fluidized Bed

Yang

Wang

2020

ACS Omega

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In this work, numerical simulation is carried out in a threedimensional full-loop pilot-scale circulating fluidized bed to explore the shape effect of the riser cross section on the typical flow characteristics of the bed via the multiphase particle-in-cell (MP-PIC) method. The gas and solid phases are modeled with the large eddy simulation and Newton's law of motion in the Eulerian and Lagrangian frameworks, respectively. The proposed model has been well validated with experimental data, followed by evaluating the typical core−annulus structure and the nonuniformity of the solid phase distributed along the radial and axial directions of the riser. Then, the particle-scale information of the solid phase distributed in different parts of the system is explored. The results demonstrate that (i) the square riser gives rise to a higher solid inventory in the standpipe owing to the stronger circulation intensity; (ii) the thickness of the solid back-mixing layer reduces along the riser height; the solid back-mixing tends to concentrate in the four corners, while it is not obvious near the sidewalls of the square riser; and (iii) nonuniform distribution of the particle-scale information of the solid phase (e.g., mass, flux, drag force, and slip velocity) can be observed. The square riser gives rise to comparatively more uniform axial mass distribution, a larger rising solid flux, larger horizontal transportation velocity between the core and annulus regions, and a larger horizontal dispersion coefficient in the riser, as compared with the corresponding ones in the circular riser.

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“…Based on literature, prediction of riser flow with dense group B particles densities exceeding 3000 kg/m 3 is presently a difficult task. Therefore, we performed large scale experiments in a 18 m high riser with a 0.3 m diameter, with different group B particles [93][94], at expected representative gas velocities in the range of 8-10 m/s and solid mass fluxes in the range of 30-60 kg/s/m2. As shown in Fig.15 below, for similar operating conditions, the sand and glass beads that were tested generated very different pressures drops.…”

Section: Fluidized Regimes In Clc Processmentioning

confidence: 99%

CLC, a promising concept with challenging development issues

et al. 2017

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Chemical Looping Combustion (CLC) is a promising technique to achieve fuel combustion in a nitrogen free atmosphere, therefore giving the possibility to separate and store or use CO 2. Several potential applications are considered in the field of power generation with gas, liquid and mostly solid fuels. In the Carbon Capture, Storage and Utilization (CCSU) context, energy penalty is reduced with CLC compared to other routes. In addition, other applications of Chemical Looping Technology are considered in the field of H 2 production or gasification for instance. In the past years, a huge effort has been conducted worldwide to investigate CLC materials and process issues. In 2008, IFPEN and Total have started an ambitious collaboration to develop CLC applications. Nowadays, the CLC concept is well demonstrated on the pilot scale. The next step is to demonstrate the technology over time on a larger scale. For further developments, some challenges should be addressed, both on market and technical aspects: • Short term market is limited. Uncertainties around CO 2 emission market (i.e. carbon credits) and storage issues are hindering policy and public acceptance and still must evolve in the right direction, • Financing of demonstration units for carbon capture in this context is challenging and other applications of CLC may require to be investigated such as utilization of captured CO2 for EOR purpose. • The industrial use of synthetic metal oxides or natural ores at large scale generates a lot of issues related to availability, price, waste disposal, health and safety, additionally to chemical and mechanical aging, reactivity, and oxygen transfer capacity, • Chemical looping reactor and process technology concepts have to be explored, developed, modeled and scaled-up in order to ensure adequate power production together with good gas solid contact and reaction requirement, controlled circulation of mixtures of particle (oxygen carrier, ash, solid fuel for instance). All these points should be considered on very large scales for carbon capture and storage (CCS) applications in order to minimize energy penalty and cost in severe operating conditions (temperatures above 800°C and intense so lid circulation). Technical challenges remain to be solved and proven with large demonstration over long periods of time. In this context, research in the field of fluidization technology is essential and we will address some key points investigated at IFPEN as related to control of solid circulation, oxygen carrier attrition, conceptual design of CLC reactors and process performance.

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Riser hydrodynamic study with different Group B powders

Cited by 9 publications

References 24 publications

CFD modeling of riser with Group B particles

CFD modeling of riser with Group B particles

Shape Effect of the Riser Cross Section on the Full-Loop Hydrodynamics of a Three-Dimensional Circulating Fluidized Bed

CLC, a promising concept with challenging development issues

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