Scaling of flow phenomena in circulating fluidized bed boilers

Scaling of flow phenomena in circulating fluidized bed boilers The paper presents an overview of scaling models used for determining hydrodynamic parameters of Circulating Fluidized Bed boilers. The governing equations and the corresponding dimensionless numbers are derived and presented for three different approaches to the scaling law of fluidized beds: classical dimensional analysis, differential equations and integrated solutions and experimental correlations. Some results obtained with these equations are presented. Finally, the capabilities and limitations of scaling experiments are discussed.

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Comprehensive Simulator (CSFMB) Applied to Circulating Fluidized Bed Boilers and Gasifiers

The Open Chemical Engineering Journal ◽

10.2174/1874123100802010106 ◽

2008 ◽

Vol 2 (1) ◽

pp. 106-118 ◽

Cited By ~ 20

Author(s):

Marcio L. de Souza-Santos

Keyword(s):

Fluidized Bed ◽

Fluidized Beds ◽

Circulating Fluidized Bed ◽

Scaling Up ◽

Simulation Program ◽

Circulating Fluidized Beds ◽

Simulation Results ◽

Fluidized Bed Boilers ◽

Operational Data ◽

Industrial Units

A comprehensive simulation program of bubbling fluidized beds (CSFB or CSFMB) has been able to reproduce operations of circulating fluidized beds. The main considerations that allow such application as well comparisons between simulation results and real operational data are shown. In addition, criteria for scaling-up pilot operations to industrial units are illustrated.

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Solids distribution as a basis for modeling of heat transfer in circulating fluidized bed boilers

Experimental Thermal and Fluid Science ◽

10.1016/s0894-1777(01)00074-7 ◽

2001 ◽

Vol 25 (5) ◽

pp. 269-276 ◽

Cited By ~ 11

Author(s):

Andreas Werner

Keyword(s):

Heat Transfer ◽

Fluidized Bed ◽

Circulating Fluidized Bed ◽

Fluidized Bed Boilers

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Modelling of dynamics of combustion of biomass in fluidized beds

Thermal Science ◽

10.2298/tsci0402107s ◽

2004 ◽

Vol 8 (2) ◽

pp. 107-126 ◽

Cited By ~ 8

Author(s):

Jaakko Saastamoinen

Keyword(s):

Particle Size ◽

Fluidized Bed ◽

Circulating Fluidized Bed ◽

Fuel Mixture ◽

Linear Increase ◽

Fuel Feed ◽

New Process ◽

Fuel Particles ◽

The Stability ◽

Fluidized Bed Boilers

New process concepts in energy production and biofuel, which are much more reactive than coal, call for better controllability of the combustion in circulating fluidized bed boilers. Simplified analysis describing the dynamics of combustion in fluidized bed and circulating fluidized bed boilers is presented. Simple formulas for the estimation of the responses of the burning rate and fuel inventory to changes in fuel feeding are presented. Different changes in the fuel feed, such as an impulse, step change, linear increase and cyclic variation are considered. The dynamics of the burning with a change in the feed rate depends on the fuel reactivity and particle size. The response of a fuel mixture with a wide particle size distribution can be found by summing up the effect of different fuel components and size fractions. Methods to extract reaction parameters form dynamic tests in laboratory scale reactors are discussed. The residence time of fuel particles in the bed and the resulting char inventory in the bed decrease with increasing fuel reactivity and differences between coal and biomass is studied. The char inventory affects the stability of combustion. The effect of char inventory and oscillations in the fuel feed on the oscillation of the flue gas oxygen concentration is studied by model calculation. A trend found by earlier measurements is explained by the model.

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