This value is also very important in selecting fabrication material for dryer. The drum, knife, spreader are the vulnerable component to high temperature. So design temperature is very much valuable data when those components are being designed. The strength of metals decreases when increasing temperature. Design stress is evaluated should be taken as the maximum temperature of the material with due allowances for any uncertainty. That is why design temperature value is very much critical in design stage. Normally the design temperature for pressure vessel is taken as more than 25% of operating range.
Design temperature = Maximum operating temperature + 25% operating temperature