During winter in northern China or in low-temperature workshops (temperatures below 5°C), ring die granulators are prone to low pelletizing efficiency and poor pellet formation due to decreased raw material viscosity and insufficient lubrication of equipment components. Targeted adjustments are required to ensure proper operation.
During raw material processing, an electric heater can be added to the conditioner to preheat the raw materials to 15-20°C. This increases raw material molecular activity and viscosity, preventing low-temperature conditions that can lead to agglomeration and difficulty in extrusion.
Also, the steam saturation can be appropriately increased (from 80% to over 90%) to utilize steam heat to assist in heating the raw materials and prevent moisture from freezing at low temperatures, which can affect pelletizing. During raw material storage, insulation should be installed in the silo to prevent the raw materials from cooling too low during storage and avoid wasted energy from secondary heating.
Before operating the ring die granulator, preheat the ring die and rollers for 30 minutes. This can be done by running the machine at no load to allow frictional heating, or by wrapping the outer ring die with an electric heat tracer. The temperature should be set between 25-30°C to prevent the raw material from solidifying and clogging the die bore due to low temperatures. The lubricant should also be replaced with a low-temperature-specific lubricant (viscosity grade 46#) to prevent freezing and potentially blocking transmission components. The lubricant fluidity should be checked every two hours to ensure proper lubrication.
These adjustments can effectively mitigate the effects of low temperatures on the ring die granulator, ensuring a pellet formation rate above 95% and preventing material waste due to low temperatures.
