Heat transfer coefficient in a shallow fluidized bed heat exchanger with a continuous flow of solid particles

Abstract

This work shows the experimental study of a continuous gas-solid fluidized bed with an immersed tube where cold water is heated by fluidized solid particles presenting inlet temperature from 450 to 700°C. Experiments were carried out in order to verify the influence of solid particle flow rate and distance between baffles immersed in a shallow fluidized bed. The solid material was 254µm diameter silica sand particles, fluidized by air in a 0.90m long and 0.15m wide heat exchanger. The measurements were taken at steady state conditions for solid mass flow rate from 10 to 100 kg/h, in a heat exchanger with the presence of 5 or 8 baffles. Bed temperature measurements along the length of the heat exchanger were experimentally obtained and heat balances for differential control volumes of the heat exchanger were made in order to obtain the axial profile of the bed-to-tube heat transfer coefficient. The results showed that heat transfer coefficient increases with the solid particle mass flow rate and with the presence of baffles, suggesting that these are important factors to be considered in the design of such heat exchanger

Modelling of Heat Transfer Processes with Compartment/Population Balance Model

“…The second order t equation reduction, generated from the population balance equation has proved to ficient tool for studying the behaviour of heat exchangers. The predictions of the second order moment equation reduction model were validated using the experimental data measured in a laboratory shallow fluidized bed heat exchanger published by Pécora and Parise [6]. Figure 3 presents the bed temperature profiles for 9 cells comparing the model data with the measured ones [6] when the input temperatures of particles were 708°C, respectively.…”

“…The mixed set of differential equations (1)-(9) was solved by reducing the population balance equation (1) and the heat conduction equation (6) into two sets of ordinary differential equations applying, respectively, a moment equation reduction and a finite difference discretization, obtaining in this way together with the gas phase equations (3)-(5) and liquid phase equation (8) a closed set of ordinary differential equations.…”

“…The results of the compartment/population balance model compared h the experimental data by Pécora and Parise[6] when the input temperatures of particles were The results of the compartment/population balance model compared with the experimental data by Pécora and Parise[6] when the input temperatures of particles were 708°C…”

Modeling of cleaning of dust emission’ in fluidized bed building aspiration’ collector

“…One of the most promising ways is applying fluidized beds with solid particulate granular materials for intensification' purposes of heat transfer within heat exchangers, for instance, in [17][18][19][20][21].…”

“…There was shown the experimental study of a continuous gas-solid fluidized bed with an immersed tube where cold water is heated by fluidized solid particles presenting inlet temperature from 450 to 700°C in the article [20]. It was studied the influence of different equivalent dimension's size solid particle of some materials and flow rate and distance between baffles immersed in a shallow fluidized bed in this work.…”