The wet mechanically dewatered product is continuously fed in top of the dryer through a distribution hopper that separates the product evenly on the belt. Products such as sewage sludge must be granulated first in order to increase the surface area of the material to obtain more efficient heat transfer and evaporation.
A perforated stainless belt transports the product gently through the dryer to avoid friction of the product and thereby reducing dust explosion risk.
As the product passes through the successive chambers, the internal air temperature increases progressively heating up the sludge to the desired temperature (approximately 70-130°C). At the end of the top belt the product transfers to the second belt where the evaporation process is completed. The product is cooled down as it passes back to the exit of the dryer. The temperatures inside the dryer chambers are constantly monitored, these measurements automatically control the speed of the belt and the feeding device, and this gives the most efficient drying time and consistent quality of product.
Direct or indirect Heated Dryer
The belt dryer is a flexible construction that can be adapted to a variety of site requirements. Direct or indirect heating is possible as well as several heating alternatives: Fuel oil, natural gas, digester gas, exhaust gas, steam, hot water, thermal oil.