A dynamic model representing the continuous Fluidized Bed dryer is presented. The model takes into account the presence of the three phases: bubble phase, cloud phase and emulsion phase. The transient analysis for step disturbances in the input variables is obtained. The influence of operating conditions on the dynamics of the dryer is discussed and the results are compared with the experiment. The model can be used for developing a model based on other suitable control strategies.

In present paper, dynamic behavior and control of a Fluidized Bed reactor for polyethylene production has been considered. A double active sites model for Ziegler-Natta catalysts is used for simulation of polymerization reaction. Hydrodynamic behavior of the Bed is modeled using a two phase model including bubble and emulsion phases in which bubble phase has plug flow pattern with differentially variable velocity and size through the Bed and emulsion phase has the CSTR flow pattern. The reactor model is validated using industrial data. Conventional PID controllers with anti-windup are considered for control purposes. It has been shown that the control system has satisfactory performances either for set point tracking or load rejection. To improve the performance of the control system for load rejection the cascade control strategy has been considered.

The presence of particles in liquid-solid Fluidized Beds enhances the Bed heat transfer, because he movement of the particles leads to an increased turbulence in the system. Moreover, the violent movement of the particles has a positive effect on fouling of the heat transfer surface. The aim of this investigation was to perform systematic measurements of Bed voidage and heat transfer coefficient for solid-liquid fluidization in a cylindrical tube and to study the effect of process parameters such as particle size and density, flow velocity, and liquid viscosity on these subjects. A large number of experiments were performed using different cylindrical and spherical particles Fluidized in aqueous CMC solution with different concentrations. Using the experimental results, a new correlation for predicting heat transfer coefficient in non-Newtonian liquid-solid Fluidized Bed heat exchanger was introduced. 

The objective of this study was to examine the effects of the Fluidized-Bed drying method on the final quality of two varieties of Iranian rice, medium- and long grain. The results were compared to that of paddy drying using a traditional method. Rough rice was treated in the Fluidized Bed drier at 140°C for 2 minutes. Similar samples were dried for 8-10 hrs by the traditional method. Dried samples were dehusked and polished. Quality factors, including trade quality (head rice yield percent and whiteness), cooking quality (amylose content, gelatinization temperature, gel consistency, aroma and flavor) and nutritional quality (thiamine and lysine contents), were then measured for each sample. Finally, the data was analyzed. Results show that paddy drying in a Fluidized Bed dryer would reduce the quality factors except for rice whiteness for which conventional drying is more acceptable. Therefore modification of Fluidized-Bed drying technique is recommended.

A Series of experiments have been conducted to study gas phase hydrodynamic in a Fluidized Bed reactor. Experimental results show that under bubbling conditions around the gas injection devices, bubbles tend to keep their identity, forming the train of bubbles around the nozzle wall. In this investigation, the gas mixing was studied by measuring the radial and axial dispersion of a gas tracer injected to a hot Fluidized Bed reactor of FCC particles. In addition, the effect of gas injection devices on tracer gas mixing was examined experimentally.

Exergy analysis is one method for studying of energy efficiency and optimization for systems and machines including dryers. Fluidized Bed dryers despite widespread usage have low energy efficiency. Therefore a new method has been proposed that the fluid Bed drying has been combined with thick (fix) Bed dryer as outlet air from the Fluidized Bed section is conducted to the thick Bed section for drying the other material or same kind material that existed in the first section. Experiments were performed in three temperatures, 50, 60 and 70oC and three Bed depth in down, Fluidized Bed drying, 4, 6 and 8 cm and two Beds depth in up, batch Bed drying, 6 and 8 cm. The results show that exergy loss of top floor is lower than down floor. And also increasing in Bed depth of down floor causes increasing in exergy loss of top floor. But exergy loss of down floor decreases with increasing in Bed depth of top floor.

In Fluidized Bed dryer, high velocity of air causes wastage of thermal energy. In order that fixed Bed dryer be combined with Fluidized Bed dryer, it was mounted after Fluidized Bed in air way. According to the first law of thermodynamic, energy and effective parameters on energy consume were analyzed. Experiments were performed at three temperature ranges of 50, 60 and 70oC, three Bed depths of 4, 6 and 8cm for the lower Bed and two Bed depths of 6 and 8 cm for the higher. Increasing Bed depth of each Bed showed clear effects on EU and EUR of the other floor. The EU value of top floor was more than that of bottom floor. Maximum energy consumption was obtained in 70oC at 8dw-8up Bed depth and energy consumption ratio was obtained in 50oC at 8dw-8up.