Deposition of bituminous coal ash on an isolated heat exchanger tube: Effects of coal properties on deposit growth

Walsh, PH; Sayre, Alan; Loehden, David Otto; Monroe, Larry; Béer, J.M.; Sarofim, Adel F.

doi:10.1016/0360-1285(90)90042-2

Cited by 208 publications

(112 citation statements)

References 26 publications

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“…Hence, the tendency to rebound decreases as the temperature of impacting particles increases. These predictions are in agreement with Ni et al (2011a) and Walsh et al (1990).…”

Section: E Ect Of Inlet Temperaturesupporting

confidence: 85%

Numerical Simulation of Molten Slag Deposition in Radiant Syngas Cooler with a CFD-Based Model

Dai

et al. 2016

J. Chem. Eng. Japan / JCEJ

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A computational uid dynamic (CFD) model and a deposition model are coupled to predict the molten slag deposition behavior in radiant syngas cooler (RSC) for entrained ow coal gasi cation. The slag particle deposition model is developed by identifying the excess rebound energy as a criterion to determine if the particle is deposited or rebounded from the wall while slag solidi cation in the impact process is also considered. The simulation results show that molten slag particles stick on the membrane wall between the height of 12.2-22.0 m for Reference Case with the maximum deposition rate 1.5 10 5 kg/(m 2 ·s) at the position of height about 16.8 m. The deposition rate increases with increasing inlet temperature and operating load. Small inlet diameter leads to high deposition rate due to high transport rate and high deposit propensity, while small inner cylinder diameter leads to higher deposition rate due to higher deposit propensity.

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“…Hence, the tendency to rebound decreases as the temperature of impacting particles increases. These predictions are in agreement with Ni et al (2011a) and Walsh et al (1990).…”

Section: E Ect Of Inlet Temperaturesupporting

confidence: 85%

Numerical Simulation of Molten Slag Deposition in Radiant Syngas Cooler with a CFD-Based Model

Dai

et al. 2016

J. Chem. Eng. Japan / JCEJ

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“…For instance, Srinivasachar et al [3,4] have studied formation of the ash intermediates, which consist of gases, liquids and solids. Raask [5] elucidated deposit initiation, and Walsh et al [6,7] studied deposit characteristics and growth. Beer et al [8] tried to model ash behaviors.…”

Section: Introductionmentioning

confidence: 99%

Experimental Studies on the Normal Impact of Fly Ash Particles with Planar Surfaces

Dong

Xie

et al. 2013

Energies

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This paper presents the results of a comprehensive program of experiments in which fly ash particles were impacted under controlled conditions against a flat steel surface. The overall aim of these experiments was to gain an understanding of the ash deposition process in a pulverized coal boiler system. A continuous nitrogen flow carrying fly ash particles was used to examine the effect of particle incident velocity and particle diameter (d p ) on the normal restitution coefficient, and of the particle diameter on the critical velocity. The effect of the incident normal velocity and particle diameter on the normal restitution coefficient was also examined. The results show that the normal restitution coefficient increases rapidly with increasing incident velocity when this incident velocity is less than the yield velocity, and rapidly decreases with increasing incident velocity when the incident velocity is greater than the yield velocity. The critical velocity, determined solely by the first-contact energy loss, is proportional to d p −5/6 and therefore becomes larger for smaller particles. For instance, in the present work, the velocity v c of a particle with diameter of 85 μm is 0.19 m/s, which increases to 0.42 m/s for particles with a diameter of 65 μm.

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“…Most mechanistic particle adhesion modelling approaches use the concept presented in (Walsh et al, 1990), which provides the basis for many research studies on deposit formation simulations (Lockwood and Lee, 1999;Degereji et al, 2012). The sticking probability of an impacting particle is determined as a function of the sticking probability of both the particle (p part ) and the surface (p surf ).…”

Section: Deposit Formation Modelmentioning

confidence: 99%

“…For viscosities lower than critical, the sticking probability is assumed to be unity (Walsh et al, 1990). The model heavily depends on the chosen critical viscosity value.…”

Section: Deposit Formation Modelmentioning

confidence: 99%

Computational Modelling of a Tangentially Fired Boiler With Deposit Formation Phenomena

Modliński¹

2014

Chemical and Process Engineering

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Any complete CFD model of pulverised coal-fired boiler needs to consider ash deposition phenomena. Wall boundary conditions (temperature and emissivity) should be temporally corrected to account for the effects of deposit growth on the combustion conditions. At present voluminous publications concerning ash related problems are available. The current paper presents development of an engineering tool integrating deposit formation models with the CFD code. It was then applied to two tangentially-fired boilers. The developed numerical tool was validated by comparing it with boiler evaporator power variation based on the on-line diagnostic system with the results from the full CFD simulation.

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Deposition of bituminous coal ash on an isolated heat exchanger tube: Effects of coal properties on deposit growth

Cited by 208 publications

References 26 publications

Numerical Simulation of Molten Slag Deposition in Radiant Syngas Cooler with a CFD-Based Model

Numerical Simulation of Molten Slag Deposition in Radiant Syngas Cooler with a CFD-Based Model

Experimental Studies on the Normal Impact of Fly Ash Particles with Planar Surfaces

Computational Modelling of a Tangentially Fired Boiler With Deposit Formation Phenomena

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