Moving bed heat transfer and fluidized elutriation
Two problems relating to the processing of solid streams are treated in two sections. The first section is the study of heat transfer between an immersed cylinder and a moving bed of solids: an instrumented heated cylinder was placed in the flow stream of a moving bed of solids with and without countercurrent air flow and the heat transfer coefficients were measured between the bed and the cylinder. Runs were made with five different types of solids, with wide range of thermal properties (thermal conductivities of 0.04 to 380 W/m.K, and heat capacities of 380 to 2300 J/kg.K) and sizes (0.27 to 2 mm) at various gas and solids velocities. The obtained heat transfer coefficients ranged from 20 to 600 W/m/sup 2/.K. A model for heat transfer between an immersed cylinder and a flowing packed bed of solids, and a predictive equation, derived from theory and experimental observations, are proposed. Also, the resulting heat transfer coefficients were empirically correlated. The findings are then discussed and compared to past related published work. The second section is the study of elutriation from fluidized beds: elutriation characteristics of widely different solids (density for 920 to 5900 kg/m/sup 3/) were measured in three different fluidized beds, 0.1, 0.3 and 0.9 m in size, having high freeboard (7.5 m), using gas velocities of up to 3.5 m/s. The experimental findings were compared with previously reported results, and all the variables were well correlated with a simple empirical expression based on the terminal velocity of the particles and the velocity of the gas.
- OSTI ID:
- 5782859
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
420400* -- Engineering-- Heat Transfer & Fluid Flow
421000 -- Engineering-- Combustion Systems
CHEMICAL REACTIONS
COMBUSTION
ELUTRIATION
ENERGY TRANSFER
FLUIDIZED BED
FLUIDIZED-BED COMBUSTION
HEAT TRANSFER
MATHEMATICAL MODELS
OXIDATION
PACKED BED
SEPARATION PROCESSES
SOLIDS
THERMOCHEMICAL PROCESSES