Influence of particle size on the exit effect of a full-scale rolling circulating fluidized bed

Wang, Zhilong; Zhao, Tong; Yao, Jiafeng; Li, Kai; Takei, Masahiro

doi:10.1080/02726351.2016.1276496

Cited by 8 publications

(4 citation statements)

References 16 publications

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“…In contrast, roll frequency has a limited influence on particle shear and, thus, has a minor effect on particle distribution. 33 In addition to the previous validation of rolling simulations, 29 the effect of particle size on the abrupt exit of particles from the bed, 34 particle Stokes number, 35 heat transfer, 36 and dynamic control of particle distribution in rolling circulating fluidized beds have also been studied. 37 2.2.…”

Section: Exhaust Gas Cleaning Systems (Egcs)mentioning

confidence: 99%

Mitigation of Ship Emissions: Overview of Recent Trends

Sarbanha

Larachi

Taghavi

et al. 2023

Ind. Eng. Chem. Res.

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The urgency of reducing flue gas pollution in maritime transport makes it necessary to take a holistic view of its sustainability and environmental impacts. Among the approaches to reducing ship exhaust emissions, marinized gas scrubbers, given their ability to be retrofitted to existing ships, are a central element in the tradeoff against the use of expensive low-sulfur fuels. However, compounding this issue, the priority of reducing greenhouse gas (GHG) emissions in the coming decades poses new challenges to emissions compliance. The use of exhaust gas cleaning systems to remove SO X , NO X , and particulate matter (PM) emissions will be enhanced in the short to medium term by GHG reductions. In this study, the different types of scrubbers for seaborne operation and the potential risks associated with their secondary emissions will be critically reviewed. In addition, NO X reduction systems and recent efforts to reduce CO 2 through onboard carbon capture systems or alternative fuel combustion will also be covered.

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Section: Exhaust Gas Cleaning Systems (Egcs)mentioning

confidence: 99%

Mitigation of Ship Emissions: Overview of Recent Trends

Sarbanha

Larachi

Taghavi

et al. 2023

Ind. Eng. Chem. Res.

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“…In typical circulating fluidized bed (CFB) reactors, the downcomer dipleg plays a critical role in solid circulation and gas seal. In order to drive particles, the whole dipleg is usually kept in a state of negative pressure gradient (i.e., a decrease of pressure with the increase of downcomer height) [25][26][27][28][29][30][31]. However, the coupling of the AR into the downcomer of our high-flux CDCLC system together with the special requirements of gas leakages makes the operation mechanism of the dipleg and even the whole system much more complicated.…”

Section: Gas-solid Flow Characteristicsmentioning

confidence: 99%

Theoretical Methodology of a High-Flux Coal-Direct Chemical Looping Combustion System

et al. 2018

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This study, as an extension of our previous experimental tests, presented a mechanism analysis of air reactor (AR) coupling in a high-flux coal-direct chemical looping combustion (CDCLC) system and provided a theoretical methodology to the system optimal design with favorable operation stability and low gas leakages. Firstly, it exhibited the dipleg flow diagrams of the CDCLC system and concluded the feasible gas–solid flow states for solid circulation and gas leakage control. On this basis, the semi-theoretical formulas of gas leakages were proposed to predict the optimal regions of the pressure gradients of the AR. Meanwhile, an empirical formula of critical sealing was also developed to identify the advent of circulation collapse so as to ensure the operation stability of the whole system. Furthermore, the theoretical methodology was applied in the condition design of the cold system. The favorable gas–solid flow behaviors together with the good control of gas leakages demonstrated the feasibility of the theoretical methodology. Finally, the theoretical methodology was adopted to carry out a capability assessment of the high-flux CDCLC system under a hot state in terms of the restraint of gas leakages and the stability of solid circulation.

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“…In addition, research on rolling fluidized bed boilers has shown improvements in particle-towall heat transfer, despite challenges such as reduced local heat transfer coefficients under certain conditions [16]. Extensive research on moving fluidized bed reactors for marine applications addressed factors such as bubble/particle dynamics [17], particle mixing [18], distribution control [19], particle size [20], and rolling amplitude [21], providing insight into their potential in challenging marine environments.…”

Section: Introductionmentioning

confidence: 99%

Hydrodynamic Insights on Floating Bubbling Fluidized Beds: Dynamic Solutions for Mitigating Gas Maldistribution

Sarbanha,

Larachi,

Taghavi

2024

Energies

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This study examined bubbling fluidized beds as an alternative to fixed-bed dry scrubbers on ships for reducing pollutants from marine fuels. It focused on overcoming the challenges of gas maldistribution/slug formation, especially under rough sea conditions. This research departed from traditional methods by introducing mobile internal elements into the bed emulsion phase and investigating their effectiveness in various settings, such as vertical, inclined, and rolling beds. A specialized hexapod-driven bubbling fluidized bed was developed to mimic marine operating conditions and to study the behavior of shipboard fluidized beds. Techniques such as digital image analysis (DIA) and particle image velocimetry (PIV) were used to observe bubble dynamics and granular phases, measuring local void fractions and particle velocities. A key finding is the effectiveness of moving internals in preventing bubble coalescence, which is critical for avoiding wall slugs, at different inclinations. Three types of packing were used as mobile internals: Super Raschig, Pall, and square rings. Super Raschig rings, which are characterized by high porosity, were the most efficient in reducing bubble coalescence, making them a preferred choice for offshore fluidized bed applications. This research contributes to the advancement of fluidized bed technology in marine applications and provides insight for future improvements.

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Influence of particle size on the exit effect of a full-scale rolling circulating fluidized bed

Cited by 8 publications

References 16 publications

Mitigation of Ship Emissions: Overview of Recent Trends

Mitigation of Ship Emissions: Overview of Recent Trends

Theoretical Methodology of a High-Flux Coal-Direct Chemical Looping Combustion System

Hydrodynamic Insights on Floating Bubbling Fluidized Beds: Dynamic Solutions for Mitigating Gas Maldistribution

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