In a rotary drier, the average retention time of solid is(where Z = length of the drier, metres = apparent solid density, kg/m3 L = flow rate of dry solids, kg/see. m2 drier cross-section H = hold up of solid.)

In a rotary drier, the average retention time of solid is(where Z = le

1.	In a rotary drier, the average retention time of solid is(where Z = length of the drier, metres = apparent solid density, kg/m3 L = flow rate of dry solids, kg/see. m2 drier cross-section H = hold up of solid.)
A.	<img src="/_files/images/chemical-engineering/process-equipment-and-plant-design/569-134-1.png">
B.	<img src="/_files/images/chemical-engineering/process-equipment-and-plant-design/569-134-2.png">
C.	<img src="/_files/images/chemical-engineering/process-equipment-and-plant-design/569-134-3.png">
D.	<img src="/_files/images/chemical-engineering/process-equipment-and-plant-design/569-134-4.png">
Answer» B. <img src="/_files/images/chemical-engineering/process-equipment-and-plant-design/569-134-2.png">