The feed pelletizer requires raw materials with a moisture content of approximately 13% to 18% (14% to 16% is the optimal range), while the biomass pelletizer has a higher requirement for moisture content, needing to be controlled between 8% and 12%. The moisture content of freshly cut grass is usually 70% to 85%. If directly put into the machine in its green state, the raw materials cannot be compressed into dense pellets - instead, they will flow and clog the mold holes, and at the same time, the motor current on the wet material will rise sharply. The worst case is that you can only stop the machine to clean the mold; the worst consequence is burning the motor. The opposite problem also exists: if hay or hay has a moisture content lower than 10%, it is too dry and difficult to bond, resulting in a lot of dust and fragility in the finished product. At this time, steam or water pre-treatment is needed to raise the moisture content before pelletizing.

 

Therefore, for high-moisture materials, an additional step must be added before crushing and pelletizing: drying. For grass, this practical operation process is very simple. Remove the surface moisture of the fresh grass in the field, cut it or crush it - shorter materials dry faster and more evenly - and then dry them through a rotating drum dryer to reduce the moisture content to approximately 15%–17%. Then it enters the pelletizer, where the dried and pre-ground materials are stably sent into the mold and pressed into dense pellets by the rollers. The freshly pressed pellets come out of the mold still at a high temperature, with a moisture content of 15%–20%, so a cooling stage is needed to lower the temperature to below room temperature and the moisture content to less than 12% to ensure safe storage.