Hydrolysis of CuCl 2 is the water splitting step of the Cu−Cl thermochemical cycle, where CuCl 2 reacts with steam to produce Cu 2 OCl 2 and HCl. In the present work, this gas−solid reaction was investigated to understand the mechanism and kinetics. Experiments were conducted in a semibatch fluidized bed reactor to study the effect of temperature (275−375 °C), steam mole fraction (0.4−0.9), and reaction time (0−3 h). The challenges due to the hygroscopic nature of the reactant, product agglomeration, and multiple side reactions to achieve smooth and consistent reactor performance were overcome by the addition of inert additives during fluidization. The analysis of the mechanism showed that the desired product Cu 2 OCl 2 is formed initially and further undergoes decomposition to CuO and CuCl 2 . Also, with increasing temperatures, the yield of Cu 2 OCl 2 decreases because of the formation of CuCl from reactant decomposition. The results indicate that a minimum steam mole fraction of 0.5 is required to prevent the formation of side product CuCl in the temperature range of 300−325 °C. The minimum steam requirement for maximum yield to Cu 2 OCl 2 was found to increase with increase in temperature.

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Generally the quality of a liquid-sprayed fluidized bed is monitored by measuring the bed temperature at several axial positions, as well as the average bed pressure drop. The number of temperature measurement points increases during scale-up of the reactor. Such a large number of measuring points makes the installation very expensive. High frequency pressure fluctuation measurement in a fluidized bed is emerging as a promising technique to retrieve qualitative information on the dynamics of gas fluidized beds. Pressure fluctuation measurement at just one height is sufficient for early detection of changes in the hydrodynamics of fluidized beds when the fluidized bed height is about 1 m or less. Hence, investigation has been carried out on pressure fluctuation in a liquid-sprayed gas fluidized bed. A monitoring technique based on the pressure fluctuation measurement can be used in parallel with the conventional temperature measurement, and the number of temperature measuring points can be reduced. Also the combination of both gives more reliability in online monitoring. In the present study, differential pressure fluctuation was measured across a liquid-sprayed fluidized bed. The feed liquid was either water or ammonium nitrate solution in the experiments carried out. The measured data were analyzed using time domain, frequency domain, and state space analysis. The aim of this investigation was to find a reliable analysis technique which can be easily applied to relate the measured pressure data to the health of the liquid-sprayed fluidized bed. A drastic reduction in the standard deviation of pressure fluctuation was observed when ammonium nitrate solution was injected. The standard deviation shows the demarcation among dry, water-sprayed, and solution-sprayed fluidized beds. However, a wide spread of its value with time adds difficulty in setting the limit corresponding to desired behavior of the solution-sprayed fluidized bed. In the frequency analysis a significant difference was not observed among dry, water injected, and solution injected fluidized beds with respect to the dominant frequency and the magnitude of the peak. S-statistics shows some promising results as most of the S values were below the critical value for consistent hydrodynamics or quality of the liquid-sprayed fluidized bed. If the pressure fluctuation in a dry fluidized bed is chosen as reference, S values are significantly higher than the critical value. It was also found that the S-statistics can detect the change in bed hydrodynamics when a higher concentration solution was fed to the fluidized bed.

A nonmechanical solid feeding device uses aeration gas in combination with its geometrical shape to cause particulate solids to flow through it. Serious erosion of moving parts, high solid flow rate requirement, and high operating temperature preclude the use of mechanical solid feeders. A nonmechanical solid feeding system was designed and developed in the Chemical Engineering Division of Bhabha Atomic Research Centre for continuous solid addition to the fluidized bed. The controlled continuous solid addition fulfills various purposes − maintain proper particle size distribution inside fluidized bed, provide make up for entrained solids, and supply solid reactant where solids are consumed in reaction. A solid circulation vessel which works on the principle of compartmented fluidized bed was the heart of this solid feeding system. It consists of two compartments (main and riser), and the compartments were connected through an orifice. Solid discharge rate from solid circulation vessel was regulated by adjusting the fluidizing air flow rates to main and riser compartments and solid level in the main compartment. Theoretical and experimental investigations were carried out to evaluate performance characteristics of solid circulation vessel. Experimental results showed that a wide range of solid discharge rate (6−80 kg/h) could be achieved by changing aeration rates of two compartments and fluidized solid level in the main compartment. The experimental data were used to develop a correlation between solid mass flow rate through an orifice and pressure drop across an orifice. A mathematical model was also developed to predict the solid discharge rate from solid circulation vessel for a range of operating parameters.