Common Problems in NPK Fertilizer Granulator Production

As a core piece of equipment in an NPK fertilizer production line, the granulator's operating status directly impacts product quality and production efficiency. Three common operational issues often arise, causing significant trouble for companies.

Substandard granule quality is the most obvious problem, primarily manifesting in strength and size. Some granules break or disintegrate after even a brief handling or storage period. This is often due to improper control of the raw material moisture content. When the moisture content is below 15%, the material lacks viscosity, making it difficult to cohere and resulting in a loose structure after molding. Moisture levels above 20% cause granules to stick together and crack easily after drying. Significant variations in granule size are also common. If the rotary drum granulator's speed is below 18 rpm, the material remains in the drum for an extended period, easily resulting in oversized granules. Speeds exceeding 22 rpm result in excessive centrifugal force, resulting in a large amount of fine powder and uneven material discharge from the feed port, further exacerbating granule size variations.

Sudden drops in production are a key issue hindering production efficiency. Most often, this is related to an imbalance in the NPK raw material ratio. If the potassium content is too high, the material's fluidity will be compromised, leading to accumulation in the pelletizing chamber and reduced throughput per unit time. Excessive nitrogen content can cause the material to clump and clog the pelletizing channel. Furthermore, wear and tear on the pelletizer's core components can also lead to reduced production. Dents or wear on the roller surface of a roller pelletizer reduce the effective compression area, resulting in a decrease in the number of pellets formed per unit time. Insufficient fan volume prevents the timely removal of dust and semi-finished products from the pelletizing chamber, leading to accumulation and similarly slowing production.

Equipment blockages can directly interrupt production, and can occur at both the inlet and outlet. Blockage at the feed inlet is often caused by incomplete raw material pretreatment. This leads to agglomerates or impurities larger than 5mm in diameter being mixed into the mixed material, becoming lodged in the feed channel and obstructing subsequent material flow. Blockage at the discharge outlet is often related to the drying process. If the drying temperature is below 80°C, the granules will have a high moisture content and easily adhere to the inner wall of the discharge pipe. As production progresses, this adhered material accumulates, eventually blocking the channel and preventing proper discharge.

In summary, pellet quality, yield, and blockage issues in NPK fertilizer granulators are often related to raw material control, parameter settings, and equipment maintenance.