Because the drying equipment is to conduct the drying process by thermal energy, the heating and cooling process consumes time and energy, which is a non-productive process. At the same time, because the sludge is a high organic matter ultrafine powder, for the sake of safety, the frequent emptying process increases safety expenditures of the system in vain. In addition, since sludge is a low value-added product, equipment utilization efficiency should be increased as much as possible to reduce its depreciation costs. Therefore, the drying system is not recommended for part-time production design. There is also no economic feasibility.
In general, the heating process of a drying system takes 30-40 minutes, the cooling process takes 20-30 minutes, and if it is a cold machine, the required time may be longer. Frequent emptying, both the heating and cooling process need to be deactivated, the cost of using nitrogen will be relatively high and the cost of using steam (water) will be less, but the equipment is ultimately in non-production state. If the device startup utilization rate is reduced (from 340x24=8200 hours per year to 360x8=3000 hours), the depreciation and overhaul of the equipment will increase exponentially.