Spray drying is used for production of pharmaceutical powder. (1) Select the best type of spray dryer configuration (co-current or counter-current) to avoid the temperature degradation of pharmaceutical ingredient during the process. Briefly describe the reasons for your selection. [5 points] (2) Briefly discuss the drying mechanism of liquid droplet (constant and falling drying rate periods, etc.). [5 points] (3) Briefly discuss the possibilities of energy recovery in spray drying process. Illustrate your discussion with simplified diagrams of spray drying process. [5 points]