An experimental investigation of the effect of longitudinal fin orientation on heat transfer in membrane water wall tubes in a circulating fluidized bed

Chinsuwan, Anusorn; Dutta, Animesh

doi:10.1016/j.ijheatmasstransfer.2008.08.005

Cited by 12 publications

(4 citation statements)

References 19 publications

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“…Solids acceleration and the effects of gas-wall and solid-wall fraction were neglected in the Eq. (14). Transport zone defined in this study was the part of the combustion chamber between 10 m and 48 m above air distributor level.…”

Section: Resultsmentioning

confidence: 99%

“…For this reason, detailed knowledge and experience about the heat transfer mechanisms inside a large-scale furnace chamber are major aspects to properly design an effective active heat transfer surface and to achieve desirable high performance in the circulating fluidized bed combustor. Recent research studies have been focused on heat transfer characteristic in the laboratory or pilot scale [14][15][16][17][18], but as far as author knows, there are not studies about how flue gas recirculation influences heat absorption from the bed material to the membrane wall in large-scale CFB unit. This fact is due to measuring difficulties and commercial reasons.…”

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confidence: 99%

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Effect of flue gas recirculation on heat transfer in a supercritical circulating fluidized bed combustor

Błaszczuk¹

2015

Archives of Thermodynamics

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This paper focuses on assessment of the effect of flue gas recirculation (FGR) on heat transfer behavior in 1296t/h supercritical coal-fired circulating fluidized bed (CFB) combustor. The performance test in supercritical CFB combustor with capacity 966 MWth was performed with the low level of flue gas recirculation rate 6.9% into furnace chamber, for 80% unit load at the bed pressure of 7.7 kPa and the ratio of secondary air to the primary air SA/PA = 0.33. Heat transfer behavior in a supercritical CFB furnace between the active heat transfer surfaces (membrane wall and superheater) and bed material has been analyzed for Geldart B particle with Sauter mean diameters of 0.219 and 0.246 mm. Bed material used in the heat transfer experiments had particle density of 2700 kg/m3. A mechanistic heat transfer model based on cluster renewal approach was used in this work. A heat transfer analysis of CFB combustion system with detailed consideration of bed-to-wall heat transfer coefficient distributions along furnace height is investigated. Heat transfer data for FGR test were compared with the data obtained for representative conditions without recycled flue gases back to the furnace through star-up burners.

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Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 99%

Effect of flue gas recirculation on heat transfer in a supercritical circulating fluidized bed combustor

Błaszczuk¹

2015

Archives of Thermodynamics

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“…Again the studies of heat transfer in the riser regions of this type of reactor are abundant as demonstrated by Anderson (1996), Luan et al (2000), Pagliuso et al (2000), Eriksson and Golriz (2005), Dutta (2009a and2009b), for example.…”

Section: Introductionmentioning

confidence: 88%

Study on Heat Transfer from a Bubbling Fluidized Bed Combustor to a Membrane Wall

Neto¹,

Ribeiro²,

Pinho³

2012

International Journal of Chemical Reactor Engineering

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The importance of projection and splashing of bubbling bed particles on the heat transfer rate towards a membrane wall heat exchanger placed above the bed was studied.To characterize the heat transferred from a bubbling fluidized bed to a membrane wall heat exchanger placed above the freeboard, a laboratory scale fluidized bed reactor, heated by a 2 kW electric resistance, was used. The reactor, with an internal diameter of 54.5 mm, had two 0.83 m height double pipe heat exchangers placed one above the other. Only the heat exchanger close to the bed surface participated in the heat exchange process. Tests were done without and with combustion.For experiments without combustion the bed was fluidized with air at superficial velocities of 0.2 to 0.5 m/s in the 400-700 • C temperature range. For experiments with combustion, the fluidizing gas was obtained through propane combustion in the bed in 700-720 • C temperature range, for superficial velocities of 0.2 to 0.3 m/s. Five different bed particle sizes were considered: 107.5, 142.5, 180, 282.5 and 357.5 µm.Particle convective heat transfer coefficients were obtained in the range of 2 to 16 W/m 2 /K and a correlation for the corresponding Nusselt number as a function of the fluidization characteristics and the combustion equivalence ratio is proposed.For the three smaller bed particle sizes, the particle entrainment ratio had a strong influence on the heat transferred towards the membrane wall and the corresponding bed particle entrainment rate was determined and correlated with the fluidization characteristics and the combustion equivalence ratio.

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“…Knowledge of heat transfer characteristics is an essential factor for better design, modeling and scale-up of heat exchangers in largescale circulating fluidized bed reactors. In the recent years, several research works concerning the fundamental analysis of the heat transfer process between the fluidizing medium and water tubes have been carried out both in laboratory and pilot-scale CFB facilities, for example: Chinsuwan et al [1], Nag et al [2], Lockhart et al [3], and Luan [4]. A few information is available on heat transfer data in large-scale circulating fluidized beds in the published literature were focused on: (i) application of artificial neural network approach to predict the bed-to-wall heat transfer coefficient, as discussed by Krzywanski et al [5]; (ii) utilization of cluster renewal approach in detailed heat transfer analysis inside CFB furnace, Basu et al [6], Blaszczuk et al [7][8][9], and Dutta et al [10,11]; (iii) heat transfer experimental methods, as described by Andersson et al [12]; and also (iv) heat transfer performance in CFB boilers with different configurations and loads, for instance in Wedermann et al [13] and Cheng et al [14].…”

Section: Introductionmentioning

confidence: 99%

A comparison of fuzzy logic and cluster renewal approaches for heat transfer modeling in a 1296 t/h CFB boiler with low level of flue gas recirculation

Błaszczuk¹,

Krzywański²

2017

Archives of Thermodynamics

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The interrelation between fuzzy logic and cluster renewal approaches for heat transfer modeling in a circulating fluidized bed (CFB) has been established based on a local furnace data. The furnace data have been measured in a 1296 t/h CFB boiler with low level of flue gas recirculation. In the present study, the bed temperature and suspension density were treated as experimental variables along the furnace height. The measured bed temperature and suspension density were varied in the range of 1131-1156 K and 1.93-6.32 kg/m 3 , respectively. Using the heat transfer coefficient for commercial CFB combustor, two empirical heat transfer correlation were developed in terms of important operating parameters including bed temperature and also suspension density. The fuzzy logic results were found to be in good agreement with the corresponding experimental heat transfer data obtained based on cluster renewal approach. The predicted bed-to-wall heat transfer coefficient covered a range of 109-241 W/(m 2 K) and 111-240 W/(m 2 K), for fuzzy logic and cluster renewal approach respectively. The divergence in calculated heat flux recovery along the furnace height between fuzzy logic and cluster renewal approach did not exceeded ±2%.

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An experimental investigation of the effect of longitudinal fin orientation on heat transfer in membrane water wall tubes in a circulating fluidized bed

Cited by 12 publications

References 19 publications

Effect of flue gas recirculation on heat transfer in a supercritical circulating fluidized bed combustor

Effect of flue gas recirculation on heat transfer in a supercritical circulating fluidized bed combustor

Study on Heat Transfer from a Bubbling Fluidized Bed Combustor to a Membrane Wall

A comparison of fuzzy logic and cluster renewal approaches for heat transfer modeling in a 1296 t/h CFB boiler with low level of flue gas recirculation

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