A fluidized bed is used in the production of aniline by the hydrogenation of nitrobenzene. Single-stage cyclones, followed by candle filters, are used to remove fines from the gases leaving the fluidized bed. 

The reactor operates at a temperature 270°C and a pressure of 2.5 bara. The reactor diameter is 10 m. Hydrogen is used in large excess in the reaction, and for the purposes of this exercise, the properties of the gas may be taken as those of hydrogen at the reactor conditions. The density of the catalyst particles is 1800 kg/m³ .

The estimated particle size distribution of the fines is 

A 70% recovery of the solids is required in the cyclones. For a gas flow rate of 100,000 m³/h, at the reactor conditions, determine how many cyclones operating in parallel are needed and design a suitable cyclone. Estimate the size distribution of the particles entering the filters.

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Particle size, um Percentage by weight less than 50 100 40 70 30 20 10 40 20 10 5 2 5 2