Mass Transfer
Use of raschig rings in place of crushed stones as packing in packed beds (other things being same)

Decreases pressure drop, decreases surface area
Decreases pressure drop, increases surface area
Increases pressure drop, increases surface area
Increases pressure drop, decreases surface area

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Mass Transfer
Blowdown in a cooling tower

Increases the scale forming tendencies of water
Means discarding a small fraction of circulating water to prevent and limit the concentration of salt and impurities
Is undesirable
All of these

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