Pulverizer system

A pulverizer comprising:

• a drum having a top with an inlet and a bottom with an outlet, the inlet being operatively coupled to a conveyor for feeding the inlet at the top;
• a rotating shaft extending vertically within the drum between the top and the bottom, the rotating shaft having multiple sets of rigid arms extending radially from the rotating shaft in a spaced apart manner, wherein a first set of arms is spaced apart vertically from a second set of arms, to generate flow currents within the pulverizer and reduce a size of a material input at the inlet so as to produce a size reduced material that is discharged at the outlet, the size reduced material comprising dust and a size reduced fraction;
• a dust collection system coupled to the outlet for extracting a fluid mixture of air and the dust from the size reduced fraction, the dust collection system comprising:
• a material opening configured to discharge the size reduced fraction;
• a dust opening configured to discharge the fluid mixture;
• and
• a fan configured to provide suction at the dust opening to separate the fluid mixture from the size reduced material and discharge the fluid mixture;
• an outlet conveyor operatively coupled to the material opening;
• and
• a processor programmed to:
• control a speed of the rotating shaft to thereby increase or decrease the flow currents generated by the multiple sets of rigid arms;
• control the suction of the fan;
• and
• control a speed of the conveyor to control an infeed rate of the material input at the inlet;
• wherein the dust in the fluid mixture has a dust particulate size smaller than a size of the size reduced fraction;
• and
• wherein:
• the dust collection system is configured for separating the dust from the air and returning the dust to the outlet conveyor;
• and
• the outlet conveyor is configured to redirect at least a portion of the size reduced fraction to the inlet when the at least a portion of the size reduced fraction meets a predetermined condition.