کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
211621 461784 2006 7 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Thermal inefficiency model for determination of the bed-to-gas heat transfer coefficients with effectiveness factor in a fluidised bed
موضوعات مرتبط
مهندسی و علوم پایه مهندسی شیمی مهندسی شیمی (عمومی)
پیش نمایش صفحه اول مقاله
Thermal inefficiency model for determination of the bed-to-gas heat transfer coefficients with effectiveness factor in a fluidised bed
چکیده انگلیسی
Process operations often involve the physical interaction of a gas and a solid phase. Fluidised bed heat transfer can be characterised by limited space-time (τ) on the basis of particle volume in the bed. As aimed in this study, a thermal inefficiency model (TIM) was developed using a pseudo-steady-state heat balance, i.e., equating the electrical power input to the rate of heat transfers from the bed to the gas. A bench-scale fluidised bed (105 × 200 mm) was operated for obtaining the gas temperature profiles. Temperature data were used for extracting the bed-to-gas heat transfer coefficients (hBG) with effectiveness factors (η) from the TIM. Fluidised bed experiments at low temperature range (290-473 K) were conducted avoiding excessive instrumentation and time. Compressed dry air entered the bed through a distributor of a 200-mesh brass sieve and fluidised the single charge of alumina particles (1.3 kg) with a mean diameter approximately 250 μm. The superficial gas velocity was changed from 0.085 to 0.469 m s− 1. The bed-to-gas heat transfer coefficients (hBG0×η0) at initial bed hight and thermal inefficiency constants (kI) were calculated from the intercept and slope of the linear form of the TIM, respectively. The agreement between the experimental and predicted values of gas temperatures confirmed by the TIM. The latter may be successfully used to design fluidised beds for, e.g., drying or combustion.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Fuel Processing Technology - Volume 87, Issue 6, June 2006, Pages 539-545
نویسندگان
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