Separation, energy requirement cyclones

For fine pulverization, both dry and wet processes are utilized, but increasingly the dry process is more popular because wet grinding ultimately requires drying and is much more energy intensive. A sensitive fan swirls the dust sizes into the air separator and permits coarse particles to recycle to the grinding mill or be rejected as tailings the fines are drawn into cyclones where the dust is collected. 

The process is sometimes operated with fluidised catalyst bed to achieve isothermal conditions. However, more energy is required for increased gas flow velocity and loss due to attrition are also more. The crumbled catalyst particles can get blown off and deposit as a fine powder on heat transfer surfaces of the downstream equipments. Cyclone separator is installed to remove the catalyst particles fi om gas stream... 

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