2026/04/27
Double roller press granulators are dry cold-press granulation equipment with strict standards for material moisture content. Appropriate moisture content directly affects granulation rate, particle hardness, and equipment operational stability. The moisture control range varies depending on the type of raw material.
When producing inorganic compound fertilizers and NPK dry powder raw materials, the moisture requirement is most stringent, generally controlled between 2% and 5%, and should not exceed 6%. These raw materials are inherently less viscous; excessive moisture will cause them to stick to the pressure rollers and clog the molds, resulting in poorly formed granules or flakes instead of granules, and will also increase roller wear. Conversely, insufficient moisture will result in excessive powder, making it difficult to bind during extrusion, significantly reducing the granulation rate and increasing recycled material.
For fermented organic fertilizers, humic acid, sludge, and oilseed cake, the moisture content needs to be controlled between 12% and 18%. The criterion is that the material can be formed into a clump when squeezed in the hand, but crumbles easily upon light contact, and no water seeps through the fingers. If the moisture content exceeds 20%, the material will adhere to the roller surface, causing roller sticking, clumping, poor discharge, or even machine blockage. If the moisture content is below 10%, the material is too dry and loose, resulting in easily broken and fragmented particles after extrusion, insufficient strength, and poor molding effect.
For organic-inorganic compound materials, the suitable moisture content is 10%–15%. Before production, the moisture content can be evenly adjusted using a mixer. If the material is too wet, it can be absorbed by adding dry materials such as fly ash or diatomaceous earth; if it is too dry, a small amount of water can be sprayed evenly to humidify it. Strictly controlling the material moisture content ensures smooth and hard particles, high yield, and reduces problems such as roller sticking, machine blockage, and loose particles, guaranteeing continuous and stable operation of the roller press granualtor production line and improving production efficiency.
