Biomass fuel processing pellet mills and control methods thereof

A biomass fuel processing pellet mill, comprising:

• a conditioner, a conveyor, and a pressing unit connected in series;
• wherein the pressing unit includes a pressing housing, a ring die, a roller assembly, and an adjustment component, and a negative pressure fan;
• wherein
• the ring die is disposed within the pressing housing;
• the roller assembly is arranged inside the ring die, and the roller assembly and the ring die form an extrusion gap;
• the roller assembly includes a roller body and shift lever components, wherein the shift lever components are located inside the roller body, the shift lever components periodically extend to agitate material as the ring die rotates, and an extension duration and a retraction duration of the shift lever components are controlled in real time based on an inner diameter of the ring die, a diameter of the roller body, a gap between the ring die and the roller body, and a real-time angular velocity of the roller body;
• and
• the adjustment component is connected to the roller assembly and configured to adjust the extrusion gap between the roller assembly and the ring die;
• and
• the negative pressure fan is mechanically connected to an interior of the pressing housing via a suction pipe, wherein the negative pressure fan is configured to generate a negative pressure driving force by extracting gas from the interior of the pressing housing to drive the material after pressing is completed to be discharged from die holes, and an operating parameter of the negative pressure fan is related to a material pellet size distribution and the extrusion gap.